TWI710527B - Oxide dielectric and manufacturing method thereof, and solid-state electronic device and manufacturing method thereof - Google Patents

Abstract

An oxide layer 30 composed of an oxide dielectric substance of the present invention has a pyrochlore-type crystal structure of the crystal phase, and contains oxides composed of bismuth (Bi), niobium (Nb) and titanium (Ti) (It may contain unavoidable impurities). When the number of atoms of bismuth (Bi) is 1, the number of atoms of niobium (Nb) is 0.5 to less than 1.7, and when the number of atoms of bismuth (Bi) When it is 1, the number of atoms of the titanium (Ti) is more than 0 to less than 1.3.

Description

Oxide dielectric and manufacturing method thereof, and solid-state electronic device and manufacturing method thereof

The present invention relates to an oxide dielectric and a manufacturing method thereof, and a solid-state electronic device and a manufacturing method thereof.

In the past, oxide layers composed of various functional compositions have been developed. In addition, as an example of a solid-state electronic device provided with this oxide layer, a device with a ferroelectric thin film that can be expected to operate at high speed has been developed. In addition, the dielectric materials used in solid-state electronic devices have developed BiNbO _{4 in} terms of oxide layers that do not contain lead (Pb) and can be fired at a relatively low temperature. Regarding this BiNbO ₄ , there have been reports indicating the dielectric properties of BiNbO ₄ formed by the solid-phase growth method (Non-Patent Document 1). In addition, patent literature also discloses an oxide layer composed of bismuth (Bi) and niobium (Nb) with a relative permittivity of 60 or more at 1 kHz, that is, a relatively high relative permittivity (Patent Documents 1 to 3) .

Prior art literature Patent literature

Patent Document 1 International Publication No. WO2013/069470

Patent Document 2 International Publication No. WO2013/069471

Patent Document 3 JP 2015-67475 A

Non-patent literature

Non-Patent Document 1 Effect of phase transition on the microwave dielectric properties of BiNbO ₄ , Eung Soo Kim, Woong Choi, Journal of the European Ceramic Society 26(2006)1761-1766

In the industry, in order to achieve high performance of semiconductor devices such as capacitors or condensers (hereinafter collectively referred to as "capacitors"; capacitors) or solid-state electronic devices including micro-motor systems, it is necessary not only to have high relative permittivity And has low dielectric loss (tanδ) electrical characteristics of oxide dielectric and oxide dielectric layer. Furthermore, if the degree of freedom regarding the heating temperature in the manufacturing process of an oxide dielectric with such characteristics can be increased, it will be possible to manufacture an oxide dielectric that is more stable and can achieve high reliability.

In addition, even for other solid-state electronic devices such as high-frequency filters, patch antennas, semiconductor devices, micro-motor systems, or composite components of at least two of RCL, the realization of lower dielectric loss (tanδ) is an important technology One of the topics.

In addition, in the prior art, the use efficiency of raw materials and manufacturing energy is very poor due to the relatively long and/or expensive equipment procedures, such as vacuum procedures and procedures using photolithography. When the above-mentioned manufacturing method is adopted, a lot of processing and a long time are required to manufacture a solid-state electronic device, so it is not preferred from the viewpoint of industrialization and mass production. In addition, the previous technology still has the problem that it is relatively difficult to enlarge the area.

The present invention solves at least one of the above-mentioned problems to achieve high performance of solid-state electronic devices using oxide as at least a dielectric or an insulator (hereinafter collectively referred to as "dielectric"), or Simplification and energy saving of the manufacturing process of such solid-state electronic devices. As a result, the present invention has made a significant contribution to the provision of an oxide dielectric that is excellent in terms of industriality and mass productivity, and solid-state electronic devices equipped with the oxide dielectric.

The inventors of this case have been aiming to improve or improve various characteristics of oxides composed of bismuth (Bi) and niobium (Nb) (hereinafter also referred to as "BNO oxides"), which have relatively high dielectric constants so far. Conduct dedicated review and analysis. However, the inventor considers that not only the BNO oxide is emphasized, but also other elements are taken into consideration to achieve further improvement of the electrical properties of the oxide dielectric (especially very low dielectric loss) is also important.

Therefore, as a result of the inventor’s trial and error and continuous detailed analysis and conversion of ideas, he discovered that among the combinations of many elements, the oxide composed of bismuth (Bi) and niobium (Nb) and titanium (Ti) is at the present time. A very low dielectric loss value can be achieved. What's more interesting is that even if the oxides with the aforementioned composition undergo high-temperature heating treatment that is unimaginable for BNO oxides, they can still generate The present pyrochlore crystal structure is the crystalline phase. As a result, the manufactured oxide can maintain a high relative permittivity while achieving a very low dielectric loss value.

In addition, the inventor found that in the manufacturing method of the oxide dielectric, a cheap and simple manufacturing process can be achieved by using a method that does not require a high vacuum state. The representative of this type of manufacturing process is the screen printing method or the "compression mold" processing method also known as "nanoimprint". The inventors also discovered that the oxide layer composed of the oxide dielectric can be patterned by the aforementioned various methods that are inexpensive and simple. As a result, the inventors have obtained the following insights: the formation of oxide dielectrics, and even the formation of oxide dielectrics, through procedures that can achieve high-performance oxides and which can be greatly simplified or energy-saving and easy to increase in area compared to the past It is possible to manufacture solid-state electronic devices with these oxide dielectrics. The present invention is based on the above viewpoints.

An oxide dielectric of the present invention has a pyrochlore-type crystal structure in the crystalline phase, and contains oxides composed of bismuth (Bi), niobium (Nb) and titanium (Ti) (may contain unavoidable impurities) ; When the number of atoms of the bismuth (Bi) is 1, the number of atoms of the niobium (Nb) is 0.5 to less than 1.7, and when the number of atoms of the bismuth (Bi) is 1, the titanium (Ti The number of atoms in) is more than 0 to less than 1.3.

This oxide dielectric can achieve a very low dielectric loss (tanδ) value (typically less than 0.001 at a frequency of 1kHz) while maintaining a relatively high relative permittivity. On the other hand, this oxide dielectric consists of bismuth (Bi) and niobium (Nb) and titanium (Ti) oxides (may contain unavoidable impurities. The following is the same for all oxides in this case) The crystalline phase of the pyrochlore crystal structure. Furthermore, by adopting the above-mentioned range of atomic composition ratio, even if the aforementioned oxide is heated at a high temperature (for example, 600°C or higher to 800°C or lower, typically more than 620°C to 800°C or lower), the use of CuKα characteristics can be suppressed. X Β-BiNbO ₄ -type crystal structure appeared in XRD measurement of X-ray. In addition, the presence of at least titanium (Ti) in the oxide dielectric is believed to play a specific role in creating the aforementioned crystal structure.

On the other hand, the sum of the number of atoms of the above-mentioned niobium (Nb) and the above-mentioned titanium (Ti) is 1 to 2.6, and since an oxide dielectric can be realized with higher reliability, one side remains relatively High relative permittivity, while achieving extremely low dielectric loss value, is a suitable aspect.

In addition, the method for manufacturing an oxide dielectric of the present invention includes the following process: by using a precursor containing bismuth (Bi), a precursor containing niobium (Nb), and a precursor containing titanium (Ti) The solute precursor solution is used as the starting material, and the precursor layer is heated in an oxygen-containing atmosphere to A layer of oxide dielectric is formed. The oxide dielectric has a pyrochlore-type crystal structure and contains an oxide composed of bismuth (Bi) and niobium (Nb) and titanium (Ti) (may contain Inevitable impurity), when the number of atoms of the bismuth (Bi) is 1, the number of atoms of the niobium (Nb) is 0.5 to less than 1.7, and when the number of atoms of the bismuth (Bi) is 1 , The number of atoms of this titanium (Ti) is more than 0 to less than 1.3.

According to the manufacturing method of this oxide dielectric, the manufactured oxide dielectric can maintain a relatively high relative permittivity and achieve a very low dielectric loss (tanδ) value (typically in Less than 0.001 when the frequency is 1kHz). On the other hand, the oxide dielectric produced by this manufacturing method is an oxide composed of bismuth (Bi), niobium (Nb) and titanium (Ti) (may contain unavoidable impurities. The following is for all of the materials in this case) The same oxide) has a pyrochlore-type crystal structure in a crystalline phase. Furthermore, by adopting the above-mentioned range of atomic composition ratio, even if the aforementioned oxide is heated at high temperature (for example, 600°C or higher to 800°C or lower, typically more than 620°C to 800°C or lower), the use of CuKα characteristics can be suppressed The β-BiNbO ₄ -type crystal structure appeared in X-ray XRD measurement. In addition, the presence of at least titanium (Ti) in the oxide dielectric is believed to play a specific role in creating the aforementioned crystal structure.

On the other hand, the sum of the number of atoms of niobium (Nb) and the number of atoms of titanium (Ti) is 1 to 2.6, and since it is possible to produce an oxide dielectric with higher reliability, one side remains relatively The high relative permittivity and the extremely low dielectric loss value at the same time are suitable.

In addition, the above-mentioned oxide dielectric manufacturing method can be achieved by a relatively simple process (such as inkjet, screen printing, gravure/relief printing, or nanoimprinting) without using photolithography. To form an oxide layer. Thereby, procedures such as those using vacuum procedures that require a relatively long time and/or procedures that require expensive equipment will not be required. As a result, the manufacturing method of each oxide layer described above is excellent in industriality or mass productivity.

In a specific example, the invention of the above-mentioned manufacturing method, before forming the above-mentioned oxide dielectric layer, is subjected to compression molding while heating the above-mentioned precursor layer at a temperature above 80°C to below 250°C in an oxygen-containing atmosphere, by The mold structure for forming the precursor is a suitable aspect that can be adopted based on the viewpoint that a procedure that does not require a vacuum procedure requires a relatively long time and/or a procedure of expensive equipment.

In addition, the "in an oxygen-containing atmosphere" in this application refers to an oxygen atmosphere or the atmosphere. In addition, the "layer" in this application not only refers to the concept of a layer but also a film. Conversely speaking, the "film" in this application not only refers to the concept of a film but also a layer.

The oxide dielectric of the present invention can achieve a very low dielectric loss (tanδ) value while maintaining a relatively high relative permittivity.

In addition, according to the method for manufacturing an oxide dielectric of the present invention, the manufactured oxide dielectric can achieve a very low dielectric loss (tanδ) value while maintaining a relatively high relative permittivity. .

10‧‧‧Substrate

20,320‧‧‧Lower electrode layer

220a, 220b, 220c, 220d, 220e‧‧‧electrode layer

221a‧‧‧Precursor layer for electrode layer

320a‧‧‧Precursor layer for lower electrode layer

30,230a,330‧‧‧Oxide layer (oxide dielectric layer)

30a,330a‧‧‧Precursor layer

340a‧‧‧Precursor layer for upper electrode layer

40,340‧‧‧Upper electrode layer

100,300‧‧‧Film capacitor as an example of solid-state electronic device

200‧‧‧Multilayer capacitors as an example of solid-state electronic devices

400‧‧‧Thin Film Transistor of an Example of Solid State Electronic Device

444‧‧‧channel

456‧‧‧Drain electrode

458‧‧‧Source

M1‧‧‧Mould for lower electrode layer

M2‧‧‧Dielectric layer mold

M3‧‧‧Mould for upper electrode layer

FIG. 1 is a diagram showing the overall structure of a film capacitor as an example of a solid-state electronic device in the first embodiment of the present invention.

2 is a schematic cross-sectional view showing a process of the method of manufacturing the film capacitor in the first embodiment of the present invention.

3 is a schematic cross-sectional view showing a process of the method of manufacturing a film capacitor in the first embodiment of the present invention.

4 is a schematic cross-sectional view showing a process of the method of manufacturing a film capacitor in the first embodiment of the present invention.

Fig. 5 is a schematic cross-sectional view showing a process of a method of manufacturing a film capacitor in the first embodiment of the present invention.

Figure 6 shows the X-ray diffraction of the oxides composed of bismuth (Bi), niobium (Nb) and titanium (Ti) in the reference example due to the difference in heating temperature and the difference in firing time showing the crystal structure of the oxide (XRD) measurement result change graph.

FIG. 7 is a graph showing the change of X-ray diffraction (XRD) measurement results showing the crystal structure of the oxide due to the difference in heating temperature and the difference in firing time in the first embodiment of the present invention.

FIG. 8 is a graph showing the change of X-ray diffraction (XRD) measurement results showing the crystal structure of the oxide due to the difference in heating temperature and the difference in firing time in the first embodiment of the present invention.

9 is a graph showing the correlation between the heating temperature and the dielectric loss (tan δ) of the oxide, the reference example, and the comparative example in the first embodiment of the present invention.

10 is a graph showing the correlation between the heating temperature and the relative permittivity of the oxide, the reference example, and the comparative example in the first embodiment of the present invention.

FIG. 11 is a graph showing the correlation between the heating temperature of other oxides and the dielectric loss (tanδ) in the first embodiment of the present invention.

Fig. 12 is a graph showing the correlation between heating temperature and relative permittivity of other oxides in the first embodiment of the present invention.

13 is a diagram showing the overall configuration of a multilayer capacitor as an example of a solid-state electronic device in the second embodiment of the present invention.

14 is a schematic cross-sectional view showing a process of a manufacturing method of a multilayer capacitor as an example of a solid-state electronic device in the second embodiment of the present invention.

15 is a schematic cross-sectional view showing a process of a manufacturing method of a multilayer capacitor as an example of a solid-state electronic device in the second embodiment of the present invention.

16 is a schematic cross-sectional view showing a process of a manufacturing method of a multilayer capacitor as an example of a solid-state electronic device in the second embodiment of the present invention.

17 is a schematic cross-sectional view showing a process of a manufacturing method of a multilayer capacitor as an example of a solid-state electronic device in the second embodiment of the present invention.

18 is a schematic cross-sectional view showing a process of a manufacturing method of a multilayer capacitor as an example of a solid-state electronic device in the second embodiment of the present invention.

19 is a diagram showing the overall structure of a film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

20 is a schematic cross-sectional view showing a process of a method for manufacturing a thin film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

21 is a schematic cross-sectional view showing a process of a method of manufacturing a film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

22 is a schematic cross-sectional view showing a process of a method of manufacturing a film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

23 is a schematic cross-sectional view showing a process of a method of manufacturing a thin film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

24 is a schematic cross-sectional view showing a process of a method of manufacturing a film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

25 is a schematic cross-sectional view showing a process of a method of manufacturing a film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

26 is a schematic cross-sectional view showing a process of a method of manufacturing a thin film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

27 is a schematic cross-sectional view showing a process of a method for manufacturing a thin film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

28 is a schematic cross-sectional view showing a process of a method of manufacturing a thin film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

29 is a schematic cross-sectional view showing a process of a method of manufacturing a thin film capacitor as an example of a solid-state electronic device in the third embodiment of the present invention.

Fig. 30 is a diagram showing the overall structure of a thin film transistor according to another embodiment of the present invention.

The solid-state electronic device according to the embodiment of the present invention is described in detail based on the drawings. In addition, in the description process, all the drawings are given common reference symbols for the common parts without special mention. In addition, the elements of the present embodiment in the figure are not necessarily described with each other on a scale. Furthermore, some symbols may be omitted in order to facilitate the viewing of the drawings.

<First Embodiment>

1. The overall structure of the film capacitor of this embodiment

FIG. 1 is a diagram showing the overall structure of a film capacitor 100 as an example of a solid-state electronic device in this embodiment. As shown in FIG. 1, the film capacitor 100 is provided with a lower electrode layer 20 and an oxide dielectric layer (hereinafter also referred to as "oxide layer". The same hereinafter) 30 and The upper electrode layer 40.

The substrate 10 can use various insulating substrates, including, for example, high heat-resistant glass, SiO ₂ /Si substrate, alumina (Al ₂ O ₃ ) substrate, STO (SrTiO) substrate, and SiO ₂ layer and Ti layer on the surface of Si substrate. Insulating substrates with STO (SrTiO) layer formed, etc.; insulating substrates with SiO ₂ layers and TiO _X layers laminated on the surface of Si substrates, semiconductor substrates (such as Si substrates, SiC substrates, Ge substrates, resin-made substrates) Substrate, etc.).

The lower electrode layer 20 and the upper electrode layer 40 are made of high melting point metals such as platinum, gold, silver, copper, aluminum, molybdenum, palladium, ruthenium, iridium, and tungsten, or metal materials such as alloys thereof.

In this embodiment, the oxide dielectric layer (oxide layer 30) will be based on a precursor containing bismuth (Bi), a precursor containing niobium (Nb), and a precursor containing titanium (Ti) as the solute. The driver solution is used as the starting material and the precursor is heated in an oxygen-containing atmosphere (hereinafter, the manufacturing method of this process is also referred to as "solution method"). In addition, as the solute in the precursor solution in this embodiment, for example, bismuth 2-ethylhexanoate, niobium 2-ethylhexanoate, and titanium 2-ethylhexanoate can be used.

By using the aforementioned precursor solution as the starting material precursor layer (also referred to as "precursor layer"), an oxide composed of bismuth (Bi), niobium (Nb) and titanium (Ti) is obtained. . More specifically, as will be described later, the oxide layer 30 of the present embodiment obtained by heating at least 800°C or less (more preferably 700°C or less) is an oxide composed of a pyrochlore-type crystal structure. Things. This is based on the interesting analysis result that the oxide layer 30 is measured by X-ray diffraction (XRD), and no peak derived from the β-BiNbO ₄ crystal structure is observed. In addition, the oxide layer 30 of this embodiment may include a microcrystalline phase.

In addition, the general pyrochlore-type crystal structure known so far is the structure observed in oxides composed of bismuth (Bi), niobium (Nb), and zinc (Zn), but the inventors have obtained the analysis As a result, the oxide layer 30 of the present embodiment composed of bismuth (Bi), niobium (Nb), and titanium (Ti) has a pyrochlore type crystal structure. It is currently unknown why the oxide layer 30 has a pyrochlore crystal structure. However, as described later, it is known that the crystalline phase system with a pyrochlore-type crystal structure and the dielectric layer as a thin film capacitor, the dielectric layer of a multilayer capacitor, or other various solid-state electronic devices (such as semiconductor devices or It is related to the good dielectric properties (especially very low dielectric loss) required for the insulating layer of the micro-motor system.

In addition, it was confirmed that the oxide layer 30 of this embodiment has, depending on the composition ratio and/or heating temperature, in addition to the first crystal phase and/or the second crystal phase, it also has an amorphous phase and a Bi ₃ NbO ₇ type crystal structure. Crystal phase (third crystal phase) (However, in the case of the Nb-rich oxide layer, no Bi ₃ NbO ₇ type crystal was found). In this way, there are various crystalline phases and amorphous phases, and it is appropriate from the viewpoint of preventing the deterioration and fluctuation of electrical properties caused by unnecessary grain boundary formation with a high probability.

In addition, this embodiment is not limited to the structure shown in FIG. 1. In addition, in order to simplify the drawing, the description of the patterning of the lead electrode layer from each electrode layer is omitted.

2. Manufacturing method of film capacitor 100

Next, the method of manufacturing the film capacitor 100 will be described. In addition, the temperature display of this patent application indicates the set temperature of the heater. FIG. 2 and FIG. 5 are cross-sectional schematic diagrams of a process of manufacturing the film capacitor 100 respectively. As shown in FIG. 2, first, the lower electrode layer 20 is formed on the substrate 10. Next, an oxide layer 30 is formed on the lower electrode layer 20, and then, an upper electrode layer 40 is formed on the oxide layer 30.

(1) Formation of the lower electrode layer

FIG. 2 shows a process diagram of the formation of the lower electrode layer 20. In this embodiment, an example in which the lower electrode layer 20 of the film capacitor 100 is formed of platinum (Pt) will be described. The lower electrode layer 20 is formed by forming a layer (for example, 200 nm thick) made of platinum (Pt) on the substrate 10 by a well-known sputtering method.

(2) Formation of oxide layer as insulating layer

Next, an oxide layer 30 is formed on the lower electrode layer 20. The oxide layer 30 is formed in the order of (A) precursor layer formation and preliminary firing process, and (B) formal firing process. 3 and 4 are diagrams showing the formation process of the oxide layer 30. In this embodiment, the oxide layer 30 of the manufacturing process of the film capacitor 100 is a pyrochlore crystal structure with a crystal phase, an oxide composed of bismuth (Bi), niobium (Nb) and titanium (Ti) The examples formed to illustrate.

(A) Formation of precursor layer and preparation for firing

As shown in FIG. 3, on the lower electrode layer 20, a bismuth (Bi)-containing precursor (also referred to as precursor A) and a niobium (Nb)-containing precursor ( Also called precursor B), and titanium (Ti)-containing precursor (also called precursor C) is the solute precursor solution (hereinafter referred to as the ``precursor solution'') as the starting material precursor layer ( Also called "precursor layer") 30a.

Here, examples of the precursor A required for the oxide layer 30 in addition to the above-mentioned bismuth 2-ethylhexanoate, bismuth octylate, bismuth chloride, bismuth nitrate, or various bismuth alkoxides (such as Bismuth propoxide, bismuth butoxide, bismuth ethoxide, bismuth methoxyethoxide). In addition, in the example of the precursor B in this embodiment, in addition to the above 2-ethylhexanoate niobium, niobium octylate, niobium chloride, niobium nitrate, Or various niobium alkoxides (for example, niobium isopropoxide, niobium butoxide, niobium ethoxide, niobium ethoxylate). In addition, in the example of the precursor C in this embodiment, in addition to the above-mentioned titanium 2-ethylhexanoate, titanium octylate, titanium chloride, titanium nitrate, or various titanium alkoxides (such as titanium isopropoxide) , Titanium butoxide, titanium ethoxide, titanium methoxyethoxide).

In addition, the solvent of the precursor solution is at least one alcohol solvent selected from the group consisting of ethanol, propanol, butanol, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol, or It is preferably at least one carboxylic acid solvent selected from the group of acetic acid, propionic acid, caprylic acid, and 2-ethylhexanoic acid. Therefore, regarding the solvent of the precursor solution, a mixed solvent of the above-mentioned two or more kinds of alcohol solvents and a mixed solvent of the above-mentioned two or more kinds of carboxylic acids can also be adopted.

In addition, the precursor solution of this embodiment is produced by mixing the first solution shown in (1) below, the second solution shown in (2) below, and the third solution shown in (3) below. .

(1) The first solution obtained by mixing the solution of bismuth 2-ethylhexanoate diluted with 1-butanol and the solution of bismuth 2-ethylhexanoate diluted with 2-methoxyethanol, Or the first solution of bismuth 2-ethylhexanoate diluted with 2-ethylhexanoic acid

(2) The second solution obtained by mixing the solution of niobium 2-ethylhexanoate diluted with 1-butanol and the solution of niobium 2-ethylhexanoate diluted with 2-methoxyethanol, Or the second solution of niobium ethoxide diluted with 2-ethylhexanoic acid

(3) The third solution obtained by mixing the solution of titanium 2-ethylhexanoate diluted with 1-butanol and the solution of titanium 2-ethylhexanoate diluted with 2-methoxyethanol, Or the third solution of titanium 2-ethylhexanoate diluted with 2-ethylhexanoic acid

In addition, in this embodiment, when the number of atoms of bismuth (Bi) is 1.5, the number of atoms of niobium (Nb) is 1 to 2, and the number of atoms of titanium (Ti) is 0.5 to 1.5, the precursor is prepared. Body solution.

After that, as a preliminary firing, the preliminary firing is carried out in an oxygen-containing atmosphere for a predetermined time at a temperature ranging from 80°C to 250°C. In the preliminary firing, the solvent (typically the main solvent) in the precursor layer 30a is fully evaporated, and a better gel state that can exhibit plastic deformation characteristics in the future is formed (it is considered that it remains in the residual state before thermal decomposition). The state of the organic chain). The formation of the gel state in such a state makes it easier to form a film by the compression molding method or the screen printing method, which is one of the film forming processes described later. In addition, in order to realize the aforementioned viewpoint with higher reliability, the preliminary firing temperature is preferably 80°C or higher and 250°C or lower. In addition, by making the aforementioned spin coating method a precursor The formation of the bulk layer 30a and the preliminary firing are repeated several times to obtain the desired thickness of the oxide layer 30.

(B) Formal firing

Then, in this embodiment, as the heating process required for the main firing, the precursor layer 30a is exposed to an oxygen atmosphere (for example, 100% by volume, but not limited to this) for a predetermined time (for example, 20 minutes), at 550°C The heating process is carried out by heating at a temperature (the first temperature) in the range above to below 800℃. As a result, as shown in FIG. 4, an oxide layer (oxide layer 30) composed of bismuth (Bi), niobium (Nb) and titanium (Ti) (for example, 170 nm thick) is formed on the electrode layer.

In addition, the thickness range of the oxide layer 30 is preferably 30 nm or more. If the film thickness of the oxide layer 30 is less than 30 nm, the leakage current and the dielectric loss increase due to the decrease of the film thickness, which is not suitable for practical use but not preferred when applied to solid-state electronic devices.

(3) Formation of the upper electrode layer

Next, an upper electrode layer 40 is formed on the oxide layer 30. FIG. 5 is a diagram showing the formation process of the upper electrode layer 40. In this embodiment, an example in which the upper electrode layer 40 of the film capacitor 100 is formed of platinum (Pt) will be described. The upper electrode layer 40 and the lower electrode layer 20 are similarly formed with a platinum (Pt) layer (for example, 150 nm thick) on the oxide layer 30 by a well-known sputtering method. With the formation of the upper electrode layer 40, the film capacitor 100 shown in FIG. 1 is manufactured.

On the other hand, in the present embodiment, the main firing temperature (first temperature) when forming the oxide layer 30 is set at 550°C or higher and 800°C or lower, but the first temperature is not limited to the aforementioned temperature range. On the other hand, it is quite interesting that the inventor found that if the temperature range is above 550℃~800℃, especially above 600℃~800℃ (typically more than 620℃~800℃, or 650℃~800℃ below) to change the formal firing temperature or heating temperature, not only can change the relative dielectric of oxides composed of bismuth (Bi) and niobium (Nb) and titanium (Ti) The value of the coefficient can also change its dielectric loss.

In addition, if the oxide layer manufacturing method of this embodiment is used, since there is no need to use a vacuum process as long as the oxide layer precursor solution is heated in an oxygen-containing atmosphere, it can be easily achieved compared to the conventional sputtering method. Large area, and can especially improve industrial or mass production.

3. Electrical characteristics of film capacitor 100

According to the research and analysis of the present inventors, it is found that if the precursor layer 30a becomes the oxide layer 30 in the above heating process, the heating temperature (main firing temperature) increases from 550°C to 800°C. In addition, if at least The longer the heating time within the predetermined time zone, the more clearly the pyrochlore-type crystal structure of the crystal phase appears. In addition, it is interesting that the crystal structure of β-BiNbO ₄ , which was originally confirmed to exist in the case of the BNO oxide formed by the heat treatment above 590℃, was found to be above 600℃~800 It does not appear in the oxide layer 30 of the present embodiment formed by heat treatment at temperatures below 650°C and above 800°C.

Furthermore, it was confirmed that the oxide layer 30 of the present embodiment can achieve a very low dielectric loss value especially when one of the conditions shown in (X1) and (Y1) is satisfied as described later.

The analysis results of the inventors are described in more detail below.

<X-ray diffraction (XRD) measurement results>

6 to 8 show the difference in heating temperature and firing time of the oxide (oxide layer 30) composed of bismuth (Bi), niobium (Nb) and titanium (Ti) in this embodiment. The crystal structure shows the change in the measurement result of X-ray diffraction (XRD) using CuKα characteristic X-rays. In addition, Fig. 6 to Fig. 8(a) show the results measured after heating at the first temperature for 20 minutes in terms of main firing. In addition, FIG. 6 to FIG. 8(b) show the results of the measurement after the post-annealing treatment is added to the oxide layer 30 at the same temperature for 20 minutes after the main firing. In addition, FIGS. 7 and 8 show examples of this embodiment, and FIG. 6 shows a reference example.

In addition, the atomic ratios of bismuth (Bi), niobium (Nb), and titanium (Ti) of the oxide 30 (the sample to be measured) used in FIGS. 6 to 8 are as follows (Sample a)~( Sample c) as shown.

(Sample a) Regarding Figure 6, bismuth (Bi): niobium (Nb): titanium (Ti) = 1.5: 2: 0.5

(Sample b) Regarding Figure 7, bismuth (Bi): niobium (Nb): titanium (Ti) = 1.5: 1.5:1

(Sample c) Regarding Figure 8, bismuth (Bi): niobium (Nb): titanium (Ti) = 1.5:1: 1.5

First of all, as shown in Figures 6 to 8, even in the case where only the heat treatment for main firing is performed, as long as the heating temperature is at least 600°C or higher, the pyrochlore-type crystal structure of the crystalline phase will appear. The 2θ value of the X axis is a peak near 28°~30° (the peak is shown by Q in the figure). Therefore, it can be seen that even at high temperatures (600°C or higher to 800°C or lower (typically exceeding 620°C to 800°C or lower, or 650°C to 800°C or lower)) that is unimaginable for BNO oxides based on public information Advance Heat treatment can also find the pyrochlore crystal structure crystal phase. This means that the manufacturing process of oxides with a pyrochlore-type crystal structure (showing a relatively high relative permittivity) crystal phase can particularly increase the degree of freedom in the temperature range of the heat treatment.

In addition, especially in the case of using sample b and sample c, the relationship between the main firing after heating at 550°C and the annealing treatment after additional heating at the same temperature is clearly shown. When the phenomenon of the peak shown in Q in the figure appears newly, or the phenomenon that the intensity of the peak increases. Therefore, it can be seen that even in a state where the heating temperature is not changed, by extending the heating time, the crystal phase of the pyrochlore-type crystal structure can be found in the oxide 30 with higher certainty.

On the other hand, as shown in Fig. 6, when sample a is used, either after the main firing by heating at 550°C or after the annealing treatment after additional heating at the same temperature. No peaks with the 2θ value of the X axis derived from the pyrochlore crystal structure in the vicinity of 28°-30° are seen.

On the other hand, for example, as shown in the graph of 600°C shown in Figure 9 of Patent Document 3, which is part of the inventors of the present invention, as a prior invention, observe the peak of the 2θ value of the X axis near 13°, It will become the crystalline phase where the crystalline structure of β-BiNbO ₄ appears. However, what is interesting is that no matter it is in any of the graphs of Figs. 6-8, there is no peak of the 2θ value of the X-axis derived from the crystal structure of β-BiNbO ₄ near 13°. Therefore, even if heat treatment is performed at high temperature (600°C or higher to 800°C or less (typically exceeding 620°C to 800°C or lower, or 650°C or higher to 800°C or lower)), no β-derived from β is observed. -The peak of the BiNbO ₄ -type crystal structure is a characteristic fact. This means that during the manufacturing process including the formally fired oxide 30, suppressing or preventing the appearance of the β-BiNbO4 crystal structure, which exhibits a relatively low relative permittivity, will allow the discovery of the pyrochlore-type crystal structure in particular. The temperature range.

<Measurement results of dielectric loss (tanδ) and relative permittivity>

9 is a graph showing the correlation between the dielectric loss (tanδ) value and the heating temperature (°C) of the above-mentioned sample a, sample b, and sample c after the main firing and post-annealing treatments. In addition, FIG. 10 is a graph showing the correlation between the relative permittivity and the heating temperature (°C) of the sample a, the sample b, and the sample c after the main firing and post-annealing treatment. In addition, the comparative example uses BNO oxide with a relatively high relative permittivity. Specifically, when the number of atoms of bismuth (Bi) is 1, and the number of atoms of niobium (Nb) is about 1.7 Things. In addition, Figure 9 and In FIG. 10, the sample a shows the reference example, the sample b shows the example 1, and the sample c shows the example 2. Furthermore, in FIGS. 9 and 10, the heating temperature of the main firing and the post-annealing treatment is the same.

In addition, the relative permittivity was measured by applying a voltage of 0.1V and an AC voltage of 1kHz between the lower electrode layer and the upper electrode layer. For this measurement, the Toyo Technology Co., Ltd. 1260-SYS wide-area permittivity measurement system was used. In addition, the dielectric loss (tanδ) was measured by applying a voltage of 0.1V and an AC voltage of 1kHz between the lower electrode layer and the upper electrode layer at room temperature. This measurement uses the Toyo Technology Corporation 1260-SYS wide-area permittivity measurement system.

As shown in FIG. 9, it can be seen that the dielectric loss (tan δ) values of Example 1 and Example 2 are extremely low values (typically 0.001 or less) regardless of the heating temperature. On the other hand, it was confirmed that the dielectric loss (tanδ) value of the comparative example exceeds 0.01. Based on the above results and the analysis of the inventor of the present case, the following insights are obtained: as long as at least one of the following conditions (X1) and (Y1) can be satisfied, extremely low dielectric loss (tanδ) can be achieved. ).

(X1) When the number of atoms of bismuth (Bi) is 1.5, the number of atoms of niobium (Nb) is 1 to less than 2, or when the number of atoms of bismuth (Bi) is 1.5, titanium (Ti) The number of atoms is more than 0.5 to 1.5.

In addition, in the conditions of X1, in addition to the above-mentioned conditions, a more suitable condition is that the sum of the number of atoms of the niobium (Nb) and the number of atoms of the titanium (Ti) is 1.5 to 3.9.

(Y1) When the number of atoms of bismuth (Bi) is 1.5, the number of atoms of niobium (Nb) is 1 to 2 and the number of atoms of titanium (Ti) is 0.5 to 1.5, and when titanium (Ti) When) is 1, niobium (Nb) is less than 4.

In addition, based on the viewpoint that a higher relative permittivity and a lower dielectric loss value can be obtained at the same time, the numerical ranges of (X1) and (Y1) above are satisfied when the atomic number of bismuth (Bi) is 1.5 , The condition that the number of atoms of niobium (Nb) is from 1 to 1.9 and/or when the number of atoms of bismuth (Bi) is 1.5, the condition that the number of atoms of titanium (Ti) is from 0.6 to 1.4 is suitable The same state.

On the other hand, although the dielectric loss (tanδ) value of the reference example is inferior to the values of Example 1 and Example 2, but because the dielectric loss (tanδ) value of the reference example does not reach 0.01 at 600°C or higher, Therefore, the dielectric loss (tanδ) value of this reference example can also be said to be a good value.

In addition, as shown in FIG. 10, it can be seen that, for all samples and comparative examples, a relatively high relative permittivity can be obtained by heat treatment at least 600°C or higher. In particular, regarding Example 1 And in Example 2, it was confirmed that relatively high relative permittivity can be obtained by heat treatment at 550°C or higher.

Therefore, according to Figs. 6-10, the following insights can be obtained: especially when at least one of the condition groups selected from the above (X1) and (Y1) is satisfied, a relatively high relative permittivity and a Achieve very low dielectric loss values. In addition, the above (X1) can be rewritten as the following (X2).

(X2) When the number of atoms of bismuth (Bi) is 1, the number of atoms of niobium (Nb) is from 0.666 to 1.333; or when the number of atoms of bismuth (Bi) is 1, titanium (Ti) is The number of atoms is 0.334 or more to 1 or less.

In addition, in the conditions of X2, in addition to the above-mentioned conditions, a more suitable condition is that the sum of the number of atoms of the niobium (Nb) and the number of atoms of the titanium (Ti) is 1 to 2.6.

In addition, even with respect to the oxide 30 (the sample to be measured) of the sample other than the above, the inventors' research and analysis confirmed that the effect of very low dielectric loss value can be exerted.

Representatively, the atomic ratios of bismuth (Bi), niobium (Nb), and titanium (Ti) are shown as examples of (sample d-1) and (sample d-2) under the conditions shown below.

(Sample d-1) Bismuth (Bi): Niobium (Nb): Titanium (Ti) = 1.5: 1.5: 0.5

(Sample d-2) Bismuth (Bi): Niobium (Nb): Titanium (Ti) = 1.5: 1.5: 0.12

In particular, for the sample d-2, when the number of atoms of the bismuth (Bi) is 1, even if the number of atoms of the titanium (Ti) is 0.08 (that is, less than 0.1), the small value remains relatively high. In the case of relative permittivity (for example, 190 or more), achieving a low dielectric loss value (for example, 0.002 or less at a frequency of 1kHz) is a very interesting discovery.

Fig. 11 is a graph showing the correlation between the dielectric loss (tanδ) value and the heating temperature (°C) of the sample d after the main firing and post-annealing treatments. In addition, FIG. 12 is a graph showing the correlation between the relative permittivity and the heating temperature (°C) of the sample d after the main firing and post-annealing treatment. In addition, in FIGS. 11 and 12, sample d is shown as Example 3. In addition, the measurement conditions are the same as those of (sample a) to (sample c).

As shown in FIG. 11, it can be seen that the dielectric loss (tanδ) value of Example 3 becomes extremely low (typically 0.002 or less) especially by using a heating temperature of 700°C or higher. Therefore, when at least one member selected from the group of the conditions shown in (X1) and (Y1) is satisfied, extremely low dielectric loss (tanδ) can be achieved.

In addition, as shown in FIG. 12, it can be seen that in Example 3, a relatively high relative permittivity can be obtained by a heat treatment of at least 600°C or higher.

In addition, in other examples, it is shown that the atomic ratio of bismuth (Bi), niobium (Nb), and titanium (Ti) is under the conditions shown below (Sample e).

(Sample e) Bismuth (Bi): Niobium (Nb): Titanium (Ti) = 1.5: 2: 1.2

Regarding the correlation between the dielectric loss (tanδ) value and the heating temperature (℃) of the above sample e after the main firing and post-annealing treatment, and the correlation between the relative dielectric coefficient and the heating temperature (℃), and The conditions of (sample a) to (sample c) are the results of investigation under the same measurement conditions, and the following findings (X3) and (Y3) were obtained.

(X3) The heating temperature is at least 600℃~800℃, and the dielectric loss (tanδ) value is less than 0.005. (In particular, the dielectric loss (tanδ) value is 0.001 or less at about 700°C.)

(Y3) The heating temperature is at least 600℃~800℃, and the relative permittivity is above 120. (In particular, at about 700°C, the relative permittivity becomes 160 or more.)

Furthermore, according to the inventor’s review and analysis, if the atomic number of bismuth (Bi) is 1, the atomic number of niobium (Nb) is 0.5 to less than 1.7, and when the atomic number of bismuth (Bi) When it is 1, the number of atoms of the titanium (Ti) is more than 0 to less than 1.3 (preferably more than 0.08 to less than 1.3, more preferably more than 0.3 to less than 1.3), which can be manufactured to maintain a relatively high The relative permittivity of the oxide (or oxide dielectric) with extremely low dielectric loss value. More preferably, if the sum of the number of atoms of the niobium (Nb) and the number of atoms of the titanium (Ti) becomes 1 or more to 2.6 or less, a relatively high relative permittivity can be manufactured with higher certainty. And to achieve extremely low dielectric loss value oxide (or oxide dielectric). In addition, in particular, although the value of the sum of the number of atoms of the niobium (Nb) and the number of atoms of the titanium (Ti) is not dominating the physical properties of the oxide of this embodiment (that is, the relative permittivity and the dielectric loss) However, when the sum is less than 1 or exceeds 2.6, it is considered difficult to obtain an oxidation that maintains a relatively high relative permittivity and achieves a very low dielectric loss value with high certainty. Substance (or oxide dielectric).

In addition, in FIGS. 6 to 12, as described above, an example of performing post-annealing treatment is shown, but in order to achieve the effect of the embodiment, post-annealing treatment is not necessary. However, post-annealing treatment is a suitable aspect that can be adopted. For example, after stamping and patterning are completed, post-annealing treatment can be performed.

In a more specific example of post-annealing, the oxide layer 30 of the first embodiment is formed by a formal firing process at a first temperature (an example is 650°C), and then it takes about 20 minutes to perform the first annealing in an oxygen-containing atmosphere. It is formed by heating at a second temperature below 1 temperature (typically 350°C or higher to 650°C or lower). As a result, as shown in FIGS. 6 to 8, the crystal phase of the pyrochlore type crystal structure in the oxide 30 in the film capacitor 100 can be found with higher certainty. In addition, an effect of further improving the adhesion between the oxide layer 30 and the bottom layer (ie, the lower electrode layer 20) and/or the upper electrode layer 40 can be created.

On the other hand, the second temperature of the post-annealing treatment is preferably a temperature below the first temperature. This is because if the second temperature is higher than the first temperature, the possibility that the second temperature will affect the physical properties of the oxide layer 30a will increase. Therefore, the second temperature is preferably a temperature that does not become a dominant factor for the physical properties of the oxide layer 30a. On the other hand, the second lower temperature limit in the post-annealing process is determined based on the viewpoint of further improving the adhesion to the bottom layer (ie, the lower electrode layer 20) and/or the upper electrode layer 40 as described above. .

<Measurement result of leakage current>

The inventors further investigated the leakage current value of the oxide layer 30 obtained by heating at 700°C as the main firing when 50 kV/cm is applied. As a result, the leakage current value can be used as a capacitor. An example of a representative result, the leakage current value of the above sample b is 10 ^-8 A/cm ² ~10 ^-7 A/cm ² . In addition, this leakage current is measured by applying the above voltage between the lower electrode layer and the upper electrode layer. In addition, the 4156C instrument manufactured by Agilent Technologies was used in this measurement. Furthermore, at least the main firing temperature is within the range of 600°C to 800°C, and a low leakage current value that is the same level as the result of the aforementioned representative leakage current value can be obtained. In addition, with regard to the leakage current value, at least sample c can achieve the same effect as sample b.

As described above, the oxide (oxide layer 30) composed of bismuth (Bi) and niobium (Nb) and titanium (Ti) in this embodiment can maintain a relatively high atomic ratio by adopting a predetermined range of atomic ratios. Relative dielectric coefficient, one side realizes low dielectric loss value. Therefore, it has been confirmed that it is particularly suitable for various solid-state electronic devices (such as capacitors, semiconductor devices, or micro-motor systems, or composite components including at least two of high-frequency filters, patch antennas, and RCL).

<Second Embodiment>

In this embodiment, a multilayer capacitor 200 as an example of a solid-state electronic device will be described. In addition, at least a part of the layers of the multilayer capacitor 200 are formed by a screen printing method. In addition, in this embodiment, the oxide system composed of bismuth (Bi), niobium (Nb) and titanium (Ti) among the materials forming the multilayer capacitor 200 is the same as the oxide layer 30 of the first embodiment. Therefore, the description overlapping with the first embodiment is omitted.

[Structure of multilayer capacitor 200]

FIG. 13 is a schematic cross-sectional view showing the structure of the multilayer capacitor 200 in this embodiment. As shown in FIG. 13, the multilayer capacitor 200 of this embodiment has a structure in which a total of 5 electrode layers and a total of 4 dielectric layers are alternately laminated. In addition, the alternately laminated part of the non-electrode layer and the dielectric layer is the electrode layer on the lower layer side (for example, the electrode layer 220a of the first stage) and the electrode layer on the upper layer side (for example, the electrode layer 220e of the fifth stage). Each electrode layer is formed by means of sexual connection. In addition, the material and composition of each electrode layer 220a, 220b, 220c, 220d, 220e, and the material and composition of the oxide layer 230a, 230b, 230c, 230d of each dielectric layer are disclosed in the following description of this embodiment In the description of the manufacturing method of the multilayer capacitor 200.

14 and 18 are schematic cross-sectional views of one process of the manufacturing method of the multilayer capacitor 200. In addition, FIG. 14, FIG. 15, FIG. 16, FIG. 17, and FIG. 18 show a part of the structure of the multilayer capacitor 200 shown in FIG. 13 for convenience of description. In addition, the temperature display in this application indicates the set temperature of the heater.

(1) Formation of the electrode layer 220a in the first stage

In this embodiment, first, as shown in FIG. 14, as in the first embodiment, a precursor layer 221a for an electrode layer (a precursor containing lanthanum (La)) is formed on the substrate 10 by screen printing. The precursor and the precursor containing nickel (Ni) are the solute precursor solution (called the precursor solution for the electrode layer. The following is the same as the solution of the precursor for the electrode layer in the first to fifth paragraphs) as the starting material ). After that, as a preliminary firing system, heating is carried out for about 5 minutes at 150°C or higher to 250°C or lower. In addition, this preliminary firing is performed in an oxygen-containing atmosphere.

In addition, by this preliminary firing, the solvent (typically the main solvent) in the electrode layer precursor layer 221a can be fully evaporated, and a better gel state that can exhibit plastic deformation characteristics in the future can be formed (it is considered to be It is in a state where organic chains remain before thermal decomposition). From the viewpoint of achieving the aforementioned viewpoints with higher certainty, the pre-firing temperature is preferably 80°C or higher to 250°C or lower. As a result, the first-stage electrode layer precursor layer 221a having a layer thickness of about 2 μm to about 3 μm is formed. In addition, not limited to Even if the electrode layer 220a of the first stage is screen printing of each layer described later, a well-known material (ethyl cellulose, etc.) can be suitably used to adjust the screen printing properties (viscosity, etc.).

After that, as the main firing, the electrode layer precursor layer 221a of the first stage is heated in an oxygen atmosphere at 580°C for about 15 minutes, and as shown in FIG. 15, a lanthanum ( An oxide layer for the electrode layer of the first stage composed of La) and nickel (Ni) (which may contain unavoidable impurities. The following is the same. In addition, it is also only referred to as the "first stage electrode layer") 220a. In addition, an electrode oxide layer composed of lanthanum (La) and nickel (Ni) (not only the first stage electrode oxide layer, but also other electrode oxide layers) is also referred to as an LNO layer.

In addition, an example of a lanthanum (La)-containing precursor used in the electrode layer 220a of the first stage in this embodiment is lanthanum acetate. In other examples, lanthanum nitrate, lanthanum chloride, or various lanthanum alkoxides (such as lanthanum isopropoxide, lanthanum butoxide, lanthanum ethoxide, lanthanum methoxyethoxide) can be used. In addition, an example of the nickel (Ni)-containing precursor used in the electrode layer 220a of the first stage in this embodiment is nickel acetate. Other examples can be nickel nitrate, nickel chloride, or various nickel alkoxides (such as nickel isopropoxide, nickel butoxide, nickel ethoxide, nickel methoxyethoxide).

Furthermore, in this embodiment, although the first-stage electrode layer 220a composed of lanthanum (La) and nickel (Ni) is used, the first-stage electrode layer 220a is not limited to this composition. For example, a first-stage electrode layer composed of antimony (Sb) and tin (Sn) (which may contain unavoidable impurities. The same applies below). In this case, as examples of antimony (Sb)-containing precursors, antimony acetate, antimony nitrate, antimony chloride, or various antimony alkoxides (such as antimony isopropoxide, antimony butoxide, antimony ethoxide, Antimony ethoxylate). In addition, as an example of the precursor containing tin (Sn), tin acetate, tin nitrate, tin chloride, or various tin alkoxides (such as tin isopropoxide, tin butoxide, tin ethoxide, methoxy Ethoxylate). In addition, an oxide composed of indium (In) and tin (Sn) (which may contain unavoidable impurities. The same applies below). In this case, examples of indium (In)-containing precursors can be indium acetate, indium nitrate, indium chloride, or various indium alkoxides (such as indium isopropoxide, indium butoxide, indium ethoxide, methoxy Indium ethoxylate). In addition, the example of the precursor containing tin (Sn) is the same as the previous example.

(2) The formation of the dielectric layer (oxide layer) 230a of the first stage

Afterwards, as shown in FIG. 16, on the substrate 10 and the electrode layer 220a of the first stage, a bismuth (Bi)-containing precursor, a niobium (Nb)-containing precursor, and a bismuth (Nb)-containing precursor are formed by a screen printing method. The titanium (Ti) precursor is a patterned precursor layer with a solute precursor solution as a starting material. After In terms of preliminary firing, heating is performed at 250°C for about 5 minutes. In addition, this preliminary firing is performed in an oxygen-containing atmosphere.

In addition, through this preliminary firing, the solvent (typically the main solvent) in the precursor layer can be fully evaporated, and a better gel state that can exhibit plastic deformation characteristics in the future can be formed (it is considered to be before thermal decomposition). In a state where the organic chain remains). From the viewpoint of realizing the aforementioned viewpoints with higher reliability, the pre-firing temperature is preferably from 80°C to 250°C. In this embodiment, in order to obtain a sufficient thickness (for example, about 2 μm to about 3 μm) of the oxide layer 230a as a dielectric layer, the formation of the precursor layer and the preliminary firing are performed by the aforementioned screen printing method.

After that, as a heating process for the formal firing, the precursor layer of the oxide layer 230a is heated in an oxygen atmosphere for a predetermined time (for example, about 20 minutes) at 650°C, and as shown in FIG. 16, the substrate 10 And a patterned oxide layer (oxide layer 230a) composed of bismuth (Bi), niobium (Nb) and titanium (Ti) is formed on the electrode layer 220a of the first stage. Here, by performing the main firing under the aforementioned conditions, or performing the main firing, and the post-annealing treatment shown in the first embodiment, it is possible to produce a relatively high relative permittivity and achieve extremely low dielectric loss. Value of the oxide layer 230a.

(3) The formation of electrode layer and dielectric layer after the second stage

After that, using the manufacturing process of the electrode layer (the electrode layer 220a of the first stage) and the oxide layer 230a of the dielectric layer described so far, the patterned electrode layer and the dielectric layer are made by screen printing. The electrical layer is alternately stacked.

Specifically, after the first-stage oxide layer 230a is patterned, the second-stage electrode layer is patterned by screen printing on the oxide layer 230a and the first-stage electrode layer 220a The precursor layer is formed in the same manner as the electrode layer precursor layer 221a of the first stage. Thereafter, as shown in FIG. 17, the patterned second-stage electrode layer 220b is formed.

Then, as shown in FIG. 18, on the second-stage electrode layer 220b and the first-stage dielectric layer oxide layer 230a, a patterned second-stage dielectric is formed by screen printing. The dielectric layer 230b.

In this way, the patterned electrode layer and the dielectric layer are alternately laminated by the screen printing method, and finally the multilayer capacitor 200 shown in FIG. 13 is manufactured.

As described above, in the multilayer capacitor 200 of this embodiment, each electrode layer and each dielectric layer (oxide layer) are formed of metal oxide, which is particularly worth mentioning. Furthermore, in this embodiment, Since each electrode layer and each dielectric layer (oxide layer) are formed by heating various precursor solutions in an oxygen-containing atmosphere, compared with the conventional method, it is easy to increase the area, and can improve the industrial Sex and even mass production.

In addition, by knowing the content of the present application, the formation process of each electrode layer and each dielectric layer (oxide layer) described above and then alternately and repeatedly stacked up and down is understood by those in the industry.

<The third embodiment>

1. The overall structure of the film capacitor of this embodiment

In this embodiment, a compression molding process is applied during the formation of all layers of a thin film capacitor as an example of a solid-state electronic device. The overall structure of a film capacitor 300 as an example of a solid-state electronic device in this embodiment is shown in FIG. 19. In this embodiment, the lower electrode layer, the oxide layer, and the upper electrode layer are the same as in the first embodiment except that they are stamped. Therefore, the overlapping description with the first embodiment is omitted.

As shown in FIG. 19, the film capacitor 300 of this embodiment is formed on the substrate 10 in the same manner as in the first embodiment. In addition, the film capacitor 300 is provided with a lower electrode layer 320 from the side of the substrate 10, an oxide layer 330 made of an oxide composed of bismuth (Bi), niobium (Nb) and titanium (Ti), and an upper electrode layer 340.

2. Manufacturing process of film capacitor 300

Next, the manufacturing method of the film capacitor 300 will be described. 20 to 29 are schematic cross-sectional views of one process of the manufacturing method of the film capacitor 300, respectively. When the film capacitor 300 is manufactured, first, the lower electrode layer 320 subjected to compression molding is formed on the substrate 10. Next, an oxide layer 330 subjected to compression molding is formed on the lower electrode layer 320. After that, the upper electrode layer 340 subjected to compression molding is formed on the oxide layer 330. The description of the manufacturing process of the film capacitor 300 and the first embodiment is repeated and omitted.

(1) Formation of the lower electrode layer

In this embodiment, an example is described in which the lower electrode layer 320 of the film capacitor 300 is formed of a conductive oxide layer composed of lanthanum (La) and nickel (Ni). The lower electrode layer 320 is formed in the order of (A) precursor layer formation and preliminary firing process, (B) stamper processing process, and (C) formal firing process.

(A) Precursor layer formation and preparation process for firing

First, a well-known spin coating method is used to form a lower electrode layer with a precursor containing lanthanum (La) and a precursor containing nickel (Ni) as the solute on the substrate 10, and the lower electrode layer with the precursor solution as the starting material. The layer precursor layer 320a.

After that, in terms of preliminary firing, the lower electrode layer precursor layer 320a is heated in a temperature range of 80°C or higher to 250°C or lower in an oxygen-containing atmosphere for a predetermined time. In addition, by repeating the formation of the precursor layer 320a for the lower electrode layer by the aforementioned spin coating method and the preliminary firing multiple times, the desired thickness of the lower electrode layer 320 can be obtained.

(B) Die processing

Next, in order to pattern the precursor layer 320a for the lower electrode layer, as shown in FIG. 20, use the mold M1 for the lower electrode layer under the condition of heating in the range of 80°C or higher to 300°C or less, and the pressure is 0.1MPa or higher. ~20MPa pressure below to perform compression molding processing. Examples of heating methods in the molding process include: a method of using a chamber, a furnace, etc. to achieve a predetermined temperature atmosphere; a method of heating the substrate on which the substrate is placed from below with a heater; or, using a prior Heat the mold above 80°C to below 300°C for compression molding. In this case, combining the method of heating the base with a heater from the bottom and the method of using a mold that has been heated to a temperature above 80°C and below 300°C are better in terms of workability.

In addition, the reason why the heating temperature of the mold is set to 80°C or higher to 300°C or lower is based on the following reasons. When the heating temperature of the stamper processing is less than 80°C, the lower electrode layer precursor layer 320a will have a lower plastic deformation ability due to the decrease in temperature of the lower electrode layer precursor layer 320a, and the molding of the stamper structure will be lacking. Realization of molding, or reliability or stability after molding. In addition, when the heating temperature during the molding process exceeds 300°C, the decomposition of the organic chain (oxidative thermal decomposition) that is the source of the plastic deformability will progress, and the plastic deformability will be reduced. Furthermore, from the foregoing viewpoint, it is more preferable to heat the precursor layer 320a for the lower electrode layer in the range of 100°C or higher to 250°C or lower during the compression molding process.

In addition, as long as the pressure of the press molding is within the range of 0.1 MPa to 20 MPa, the precursor layer 320a for the lower electrode layer can be deformed following the surface shape of the mold, and the desired press mold structure can be formed with high precision. . In addition, the pressure applied when the die is applied The force system is set to a low pressure range of 0.1MPa or more to 20MPa or less (especially less than 1MPa). As a result, the mold is less likely to be damaged when the press molding is performed, and it is advantageous to increase the area.

After that, the precursor layer 320a for the lower electrode layer is etched all over. As a result, as shown in FIG. 21, the lower electrode layer precursor layer 320a is completely removed from the area other than the area corresponding to the lower electrode layer (the entire etching process of the lower electrode layer precursor layer 320a).

In addition, in the above-mentioned stamping process, the surface of each precursor layer that will be the surface of the stamper is subjected to mold release treatment and/or the stamper surface of the mold is subjected to release treatment beforehand, and then each precursor layer is applied Die processing is better. By performing such a treatment, the friction between each precursor layer and the mold can be reduced, and higher precision compression molding processing can be performed on each precursor layer. In addition, the mold release agent that can be used for mold release treatment includes surfactants (for example, fluorine-based surfactants, silicon-based surfactants, non-ionic surfactants, etc.), fluorine-containing diamond carbon, and the like.

(C) Formal firing

Next, the precursor layer 320a for the lower electrode layer is subjected to main firing in the atmosphere. The heating temperature during the main firing is 550°C or higher to 650°C or lower. As a result, as shown in FIG. 22, a lower electrode layer 320 composed of lanthanum (La) and nickel (Ni) is formed on the substrate 10 (which may contain unavoidable impurities. The same applies below).

(2) Formation of the oxide layer that becomes the dielectric layer

Next, an oxide layer 330 that becomes a dielectric layer is formed on the lower electrode layer 320. The oxide layer 330 is formed in the order of (A) precursor layer formation and preliminary firing process, (B) compression molding process, and (C) formal firing process. FIG. 23 and FIG. 26 are diagrams showing the formation process of the oxide layer 330.

(A) Formation and preliminary firing of oxide precursor layer composed of bismuth (Bi), niobium (Nb) and titanium (Ti)

As shown in FIG. 23, a bismuth (Bi)-containing precursor, a niobium (Nb)-containing precursor, and a titanium-containing precursor are formed on the substrate 10 and the patterned lower electrode layer 320 in the same manner as in the second embodiment. The (Ti) precursor is a solute precursor solution as the starting material precursor layer 330a. After that, in the present embodiment, preliminary firing is performed in a state of heating to 80°C or higher to 250°C or lower in an oxygen-containing atmosphere. In addition, according to the inventor’s research, in this embodiment, by heating the precursor layer 330a in the range of 80°C or higher to 250°C or lower, the plastic deformability of the precursor layer 330a Will become higher, and the solvent can be fully removed (typically the main solvent).

(B) Die processing

In this embodiment, as shown in FIG. 24, the precursor layer 330a that has only undergone preliminary firing is subjected to compression molding. Specifically, in order to pattern the oxide layer, the die M2 for the dielectric layer is used to perform compression molding with a pressure of 0.1 MPa to 20 MPa under the state of heating to 80°C or higher to 250°C or lower .

After that, the precursor layer 330a is fully etched. As a result, as shown in FIG. 25, the precursor layer 330a is completely removed from the area other than the area corresponding to the oxide layer 330 (the entire precursor layer 330a is etched). In addition, although the etching process of the precursor layer 330a of the present embodiment is performed using a wet etching technique without a vacuum process, it may be etched by a so-called dry etching technique using plasma.

(C) Formal firing

After that, the precursor layer 330a is subjected to main firing in the same manner as in the second embodiment. In addition, the post-annealing treatment shown in the first embodiment may be additionally performed depending on necessity. As a result, as shown in FIG. 26, an oxide layer 330 that becomes a dielectric layer is formed on the lower electrode layer 320 (which may contain unavoidable impurities. The same applies below). Regarding the heating process required for the main firing, the precursor layer 330a is heated in an oxygen atmosphere for a predetermined time (for example, about 20 minutes) at 650°C.

Here, by performing the main firing under the aforementioned conditions, or by performing the main firing and the post-annealing treatment shown in the first embodiment, the oxide layer 230a can be manufactured, which can maintain a relatively high relative dielectric. Coefficient, and can achieve extremely low dielectric loss value.

In addition, the overall etching process for the precursor layer 330a can also be performed after the formal firing. However, as described above, it is more preferable to include a process of etching the entire precursor layer between the compression molding process and the formal firing process. One way. This is because it is easier to remove the unwanted area precursor layer than etching each precursor layer after the formal firing.

(3) Formation of the upper electrode layer

After that, similar to the lower electrode layer 320, a well-known spin coating method is used to form a precursor solution containing lanthanum (La) and nickel (Ni) as the solute on the oxide layer 330. The precursor layer 340a for the upper electrode layer of the starting material. After that, the upper electrode layer precursor layer 340a is heated in an oxygen-containing atmosphere in a temperature range of 80° C. or higher to 250° C. or lower to perform preliminary firing.

Next, as shown in FIG. 27, in order to pattern the upper electrode layer precursor layer 340a after preliminary firing, the upper electrode layer precursor layer 340a is heated to 80°C or higher to 300°C or lower, The upper electrode layer mold M3 is used to perform compression molding on the upper electrode layer precursor layer 340a at a pressure of 0.1 MPa to 20 MPa. After that, the upper electrode layer precursor layer 340a is completely etched, and as shown in FIG. 28, the upper electrode layer precursor layer 340a is completely removed from the area other than the area corresponding to the upper electrode layer 340.

After that, as shown in FIG. 29, as the main firing system, the upper electrode layer precursor layer 340a is heated at 520°C to 600°C for a predetermined time in an oxygen atmosphere, and lanthanum ( The upper electrode layer 340 is composed of La) and nickel (Ni) (which may contain unavoidable impurities. The same applies below).

On the other hand, the thin film capacitor 300 of the present embodiment is provided with a lower electrode layer 320, an oxide layer 330 as an insulating layer, and an upper electrode layer 340 on the substrate 10 from the substrate 10 side. In addition, each of the aforementioned layers forms a stamper structure by performing stamping processing. As a result, procedures requiring relatively long time and/or expensive equipment such as vacuum procedures, procedures using photolithography, or ultraviolet irradiation procedures will become unnecessary. Furthermore, both the electrode layer and the oxide layer can be easily patterned. Therefore, the film capacitor 300 of this embodiment is extremely excellent in industriality or mass production.

In addition, as a modification of this embodiment, a precursor layer for the lower electrode layer 320, which is a precursor layer for the lower electrode layer 320a, a precursor layer for the oxide layer 330, which is a precursor layer for the oxide layer 330, and an upper electrode are formed on the substrate 10. After the layer 340 is a precursor layer, that is, a laminate obtained by using a precursor layer 340a for the upper electrode layer, it is also possible to apply compression molding to the laminate. After that, the formal firing is carried out. If such a method is adopted, although this aspect is different from the film capacitor 300, it is impossible to form an individual stamper structure for each layer of monomer, but the number of stamper processing processes can be reduced.

<Other embodiments (1)>

In addition, the oxide layer in each of the above embodiments is suitable for various solid-state electronic devices that use a low driving voltage to control a large current. As the solid-state electronic device provided with the oxide layer in each of the above embodiments, it can be applied to many devices in addition to the above-mentioned film capacitor. For example, the oxide layer in each of the above embodiments can also be applied to various capacitors such as variable capacitance film capacitors, metal oxide semiconductor junction field effect transistors (MOSFET), non-volatile memory and other semiconductors. Body devices, or MEMS (microelectromechanical systems) such as micro-TAS (Total Analysis System), micro-chemical chips, DNA chips, etc., or components of micro-motor systems represented by NEMS (nanoelectromechanical system), and others that include high-frequency filters , Patch antennas or composite components of at least 2 types of RCL.

The following describes the structure of a thin film transistor 400 as an example of a solid-state electronic device.

<The overall structure of the thin film transistor of this embodiment>

FIG. 30 is a diagram showing the overall structure of the thin film transistor 400. As shown in FIG. 30, the thin film transistor 400 in this embodiment is laminated on the substrate 10 from the lower layer to a lower electrode layer (gate) 320, an oxide layer (gate insulating layer) 330, channels 444, Source 458 and drain 456. The manufacturing methods of the lower electrode layer (gate) 320 and the oxide layer (gate insulating layer) 330 are the same as the individual manufacturing methods of the third embodiment, so they are omitted.

In addition, the thin film transistor 400 adopts a so-called bottom gate structure, but this embodiment is not limited to this structure. In addition, as in the first embodiment, in order to simplify the drawing, the description of the patterning of the lead electrode from each electrode is omitted.

The channel 444 of this embodiment is composed of channel oxides containing indium (In), zinc (Zn), and zirconium (Zr). In addition, in this embodiment, other well-known channel materials may also be used. In addition, the thickness of the channel 444 is from 5nm to 80nm, and the thickness of the channel 444 is from 5nm to 80nm. The thin film transistor is based on the viewpoint that it can cover the oxide layer (gate insulating layer) with high reliability and make the channel conductive Sexual tune becomes an easy point of view as an appropriate aspect.

In addition, the source 458 and the drain electrode 456 of this embodiment are made of ITO (Indium Tin Oxide).

In addition, in the thin-film transistor 400 of an example of a solid-state electronic device, an insulating layer that performs functions other than the oxide layer (gate insulating layer) 330 can also be made of bismuth (Bi) and niobium (Nb) and titanium (Ti). ) Formed by the oxide.

<Other embodiments (2)>

In addition, in the above-mentioned embodiment, the reason why the pressure during the compression molding process is set within the range of "0.1 MPa or more to 20 MPa or less" in the state where the compression molding process is performed is based on the following reasons. First, when the pressure is less than 1 MPa, the pressure may be too low to be able to compression mold each precursor layer. On the other hand, as long as the pressure reaches 20MPa, the precursor layer can be fully compression molded. There is no need to apply higher pressure. From the foregoing point of view, it is better to perform compression molding with a pressure in the range of 0.1 MPa to 10 MPa in the compression molding process.

As described above, the disclosure of each of the above-mentioned embodiments is described for describing these embodiments, and is not intended to limit the description of the present invention. Furthermore, modifications that exist within the scope of the present invention including other combinations of the respective embodiments are also included in the scope of patent applications.

10‧‧‧Substrate

20‧‧‧Lower electrode layer

30‧‧‧Oxide layer (oxide dielectric layer)

40‧‧‧Upper electrode layer

100‧‧‧Film capacitors as an example of solid-state electronic devices

Claims (13)

An oxide dielectric with a pyrochlore-type crystal structure in the crystalline phase, containing oxides composed of bismuth (Bi), niobium (Nb) and titanium (Ti) (may contain unavoidable impurities); When the number of atoms of bismuth (Bi) is 1, the number of atoms of niobium (Nb) is 0.5 to less than 1.7, and when the number of atoms of bismuth (Bi) is 1, the atoms of titanium (Ti) The number is over 0 to less than 1.3. For example, the oxide dielectric of item 1 in the scope of patent application, wherein the sum of the number of atoms of the niobium (Nb) and the number of atoms of the titanium (Ti) is 1 to 2.6. For example, the oxide dielectric of item 1 or 2 in the scope of patent application, in which the oxide dielectric is measured by X-ray diffraction (XRD) at 25°C, there is no peak derived from the β-BiNbO ₄ crystal structure . For example, the oxide dielectric of item 1 or 2 of the patent application, and when the number of atoms of the bismuth (Bi) is 1, the number of atoms of the niobium (Nb) is from 0.666 to 1.334, or when the When the number of atoms of bismuth (Bi) is 1, the number of atoms of this titanium (Ti) is 0.333 or more and 1 or less. For example, the oxide dielectric of item 1 or 2 in the scope of patent application, when heated at 700°C, the oxide dielectric is measured by X-ray diffraction (XRD), and the pyrochlore-type crystal structure appears The peak of β-BiNbO ₄ type crystal structure does not appear. A solid-state electronic device is provided with an oxide dielectric as in any one of items 1 to 5 in the scope of the patent application. For example, the solid-state electronic device of the sixth item of the scope of patent application, wherein the solid-state electronic device is selected from one of the group consisting of capacitors, semiconductor devices, and micro-motor systems. A manufacturing method of an oxide dielectric, including the following process: by using a bismuth (Bi)-containing precursor, a niobium (Nb)-containing precursor, and a titanium (Ti)-containing precursor as the solute precursor The solution is used as the starting material, and the precursor layer is heated in an oxygen-containing atmosphere to form an oxide dielectric layer. The oxide dielectric has a pyrochlore-type crystal structure of the crystal phase, containing bismuth (Bi) and niobium (Nb) and titanium (Ti) composed of oxides (may contain unavoidable impurities). When the number of atoms of bismuth (Bi) is 1, the number of atoms of niobium (Nb) is 0.5 or more to less than 1.7, and when the number of atoms of the bismuth (Bi) is 1, the number of atoms of the titanium (Ti) is more than 0 to less than 1.3. For example, the method for manufacturing an oxide dielectric in the scope of patent application, wherein the process of forming the oxide dielectric layer is further to form the number of atoms of the niobium (Nb) and the number of atoms of the titanium (Ti) The manufacturing process of the oxide dielectric layer whose sum is above 1 to below 2.6. For example, the method for manufacturing an oxide dielectric of item 8 or 9 in the scope of the patent application, wherein the oxide dielectric layer formed by the heating treatment at 700°C uses X-ray diffraction (XRD) ) When the oxide dielectric is measured, a peak derived from the pyrochlore type crystal structure appears, and no peak derived from the β-BiNbO ₄ type crystal structure appears. For example, the method for manufacturing an oxide dielectric of item 8 or 9 of the scope of patent application, wherein the process of forming the oxide dielectric layer is further to form when the number of atoms of the bismuth (Bi) is 1, the niobium The number of atoms of (Nb) is from 0.666 to 1.334, or when the number of atoms of bismuth (Bi) is 1, the number of atoms of titanium (Ti) is from 0.333 to less than 1 The manufacturing process of the layers. For example, the method for manufacturing an oxide dielectric of item 8 or 9 of the scope of patent application, wherein before forming the oxide dielectric layer, the precursor layer is heated at a temperature above 80°C to below 250°C in an oxygen-containing atmosphere In this state, compression molding is performed to form a compression molding structure of the precursor layer. A method for manufacturing a solid-state electronic device has the following manufacturing process: manufacturing a solid-state electronic device with an oxide dielectric, the oxide dielectric is made of an oxide as in any one of the patent applications 8-12 Formed by the manufacturing method of the dielectric.

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