CN118792636A - A thin film deposition method - Google Patents

Abstract

The present application discloses a thin film deposition method, which includes: S10: sending a wafer boat loaded with wafers into a reaction chamber; S20: heating and keeping the wafers warm so that the temperature of the wafer edge reaches a first preset temperature and is maintained for a first preset time; S30: cooling and keeping the wafers warm so that the temperature of the wafer edge is reduced from the first preset temperature to a second preset temperature and is maintained for a second preset time, wherein, in the process of cooling and keeping the wafers warm, a reaction gas is introduced into the reaction chamber to deposit a thin film on the surface of the wafer, wherein steps S20 and S30 are repeated for a preset number of times. According to the thin film deposition method of the present application, the uniformity of the deposited thin film can be significantly improved.

Description

A thin film deposition method

Technical Field

The present application relates to the technical field of thin film deposition, and in particular to a thin film deposition method.

Background Art

In the low-pressure deposition process, high film thickness inevitably faces the problem of poor uniformity. During the thin film deposition process, the precursor gradually diffuses and is consumed from the edge of the wafer to the center of the wafer, resulting in a gradient distribution of the precursor concentration in the wafer (the precursor concentration gradually decreases from the edge of the wafer to the center of the wafer), which ultimately leads to a gradient difference in the thickness of the deposited film (the thickness of the film gradually decreases from the edge of the wafer to the center of the wafer).

Therefore, improvements are needed to at least partially solve the above problems.

Summary of the invention

A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

In order to at least partially solve the above problems, according to a first aspect of the present invention, a thin film deposition method is provided, comprising:

S10: sending the wafer boat loaded with wafers into the reaction chamber;

S20: heating and keeping the wafer warm so that the temperature of the edge of the wafer reaches a first preset temperature and is maintained for a first preset time;

S30: Cooling and keeping the wafer warm, so that the temperature of the edge of the wafer decreases from the first preset temperature to a second preset temperature, and keeps the temperature for a second preset time. During the cooling and keeping the wafer warm, a reaction gas is introduced into the reaction chamber to perform thin film deposition on the surface of the wafer.

Wherein, step S20 and step S30 are repeated for a preset number of times.

Exemplarily, the first preset temperature, the second preset temperature and the preset number of times are determined by a preset temperature field model formula;

The temperature field model formula is as follows:

b×(Temp1-Temp2)×number of loops/(2×mean)=Uf - Ui

Among them, b is a coefficient, Temp1 is the first preset temperature, Temp2 is the second preset temperature, the number of loops is the preset number of times, mean is the ideal average film thickness, Uf is the ideal uniformity parameter, and Ui is the initial uniformity parameter.

Exemplarily, the method further includes:

S40: During a third preset time, the temperature of the edge of the wafer is maintained at the second preset temperature, and a reaction gas is introduced into the reaction chamber to perform thin film deposition on the surface of the wafer.

Exemplarily, except for the first step S20, before each of the other steps S20, the residual reaction gas in the reaction chamber is exhausted.

Exemplarily, the film is a silicon oxide film.

Exemplarily, the first preset temperature is less than or equal to 710° C.;

The second preset temperature is greater than or equal to 660°C;

The difference between the first preset temperature and the second preset temperature is less than or equal to 40°C.

Exemplarily, the preset number of times is 3-5 times;

The second preset time is 5 min-10 min.

Exemplarily, the film is a silicon nitride film.

Exemplarily, the first preset temperature is less than or equal to 790° C.;

The second preset temperature is greater than or equal to 740°C;

The difference between the first preset temperature and the second preset temperature is less than or equal to 30°C.

Exemplarily, the preset number of times is 2-4 times;

The second preset time is 5 min-10 min.

According to the thin film deposition method of the present invention, by cooling the wafer, a temperature difference can be formed between the center and the edge of the wafer (when the wafer is cooled, the temperature gradually decreases from the edge to the center, and the edge temperature decreases before the center temperature), that is, the center temperature is made higher than the edge temperature. During this process, a reaction gas is introduced into the reaction chamber for thin film deposition, which can make the thin film deposition rate at the center of the wafer higher than the surface deposition rate at the edge, that is, the thickness of the thin film deposited at the center is higher than the thickness of the thin film deposited at the edge. Repeating the process for a preset number of times can offset the uneven film thickness caused by the gradient distribution of the precursor concentration, thereby improving the thickness uniformity of the formed film.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings of the present application are hereby used as part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, and are used to explain the device and principle of the present application. In the drawings,

FIG1 is a schematic diagram of the precursor concentration distribution in the reaction chamber;

FIG2 is a graph showing the relationship between the concentration of precursors in the reaction chamber and the position of the wafer;

FIG3 is a graph showing the relationship between the deposited film thickness and the wafer position affected by the precursor concentration;

FIG4 is a schematic diagram of a process of a thin film deposition method according to an embodiment of the present application;

FIG5 is a schematic diagram of temperature distribution in a reaction chamber during a deposition process according to an embodiment of the present application;

FIG6 is a graph showing the relationship between the temperature in the reaction chamber and the position of the wafer;

FIG7 is a graph showing the relationship between the thickness of the deposited film and the position of the wafer affected by temperature;

FIG8 is a schematic diagram of temperature changes at the edge and center of a wafer during a cooling process according to an embodiment of the present application;

FIG9 is a schematic diagram showing the change of wafer edge temperature over time in a thin film deposition method according to an embodiment of the present application;

FIG. 10 is a schematic diagram showing the variation of wafer edge temperature over time in a thin film deposition method of the related art.

Description of reference numerals:

10-wafer, 20-reaction chamber;

Temp1-first preset temperature, Temp2-second preset temperature, Temp3-deposition temperature, t1-first preset time, t2-second preset time, t3-third preset time, t4-deposition time.

DETAILED DESCRIPTION

In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

It should be understood that the present application can be implemented in different forms and should not be construed as being limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and/or parts, these elements, components, regions, layers and/or parts should not be limited by these terms. These terms are only used to distinguish an element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as a second element, component, region, layer or part.

Spatially relative terms such as "under", "beneath", "below", "under", "above", "above", etc., may be used herein for convenience of description to describe the relationship of one element or feature to other elements or features shown in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation shown in the figures.

The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said/the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and/or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and/or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and/or groups. When used herein, the term "and/or" includes any and all combinations of the relevant listed items.

Embodiments of the invention are described herein with reference to cross-sectional views as schematic diagrams of ideal embodiments (and intermediate structures) of the present application. Thus, variations in the shapes shown due to, for example, manufacturing techniques and/or tolerances can be expected. Therefore, embodiments of the present application should not be limited to the specific shapes shown herein, but include shape deviations due to, for example, manufacturing. Therefore, what is shown in the figures is schematic in nature, and their shapes are not intended to display the actual shape of the device and are not intended to limit the scope of the present application.

Referring to Figures 1-3, in a thin film deposition process including but not limited to a low-pressure chemical vapor deposition process, a wafer boat (not shown in the figure) loaded with wafers 10 is located in a reaction chamber 20, and the wafers 10 are placed flat in the vertically placed wafer boat. A reaction gas containing a precursor is introduced into the reaction chamber 20, and the precursor gradually diffuses and is consumed from the edge of the wafer 10 to the center of the wafer 10, resulting in a gradient distribution of the precursor concentration within the wafer 10, that is, the precursor concentration gradually decreases from the edge of the wafer 10 to the center of the wafer 10 (as shown in Figure 2). As a result, due to the uneven distribution of the precursor concentration, a gradient difference in the thickness of the deposited thin film is ultimately caused, that is, the thickness of the thin film gradually decreases from the edge of the wafer 10 to the center of the wafer 10, and the film has poor in-wafer uniformity.

In order to solve the above problems, the present application provides a thin film deposition method, which can be applied to various chemical vapor deposition (CVD) processes, including but not limited to low pressure chemical vapor deposition (LPCVD) processes. Referring to Figures 1-9, the thin film deposition method includes the following steps:

S10 : sending the wafer boat loaded with the wafers 10 into the reaction chamber 20 .

Specifically, there may be a plurality of wafers 10 , and the wafers 10 are placed flat in a vertically placed wafer boat and are spaced a certain distance apart from each other.

S20: heating and keeping the wafer 10 in the reaction chamber 20 so that the temperature of the edge of the wafer 10 reaches a first preset temperature Temp1 and is maintained for a first preset time t1.

Specifically, the chamber and the wafer 10 therein are heated by a heater arranged outside the chamber, and the temperature of the edge of the wafer 10 is detected by a temperature sensor. When the temperature of the edge of the wafer 10 reaches a first preset temperature Temp1, the heating power of the heater is appropriately adjusted to keep the temperature of the edge of the wafer 10 at the first preset temperature Temp1 for a first preset time t1, and further, the temperature of the center of the wafer 10 also reaches and is maintained at the first preset temperature Temp1.

When the wafer 10 is heated by the heater, heat is gradually transferred from the edge of the wafer 10 to the center of the wafer 10. When the temperature of the edge of the wafer 10 reaches the first preset temperature Temp1, the temperature of the center of the wafer 10 has not reached the first preset temperature Temp1. Therefore, it is necessary to keep the temperature of the edge of the wafer 10 at the first preset temperature Temp1 for a first preset time t1 so that the temperature of the center of the wafer 10 can also reach the first preset temperature Temp1, so that the temperature of the entire wafer 10 is evenly distributed.

It should be noted that in step S20 , no reaction gas is introduced into the reaction chamber 20 , and no thin film deposition is performed.

S30: Cooling and keeping the wafer 10 warm so that the temperature of the edge of the wafer 10 drops from the first preset temperature Temp1 to the second preset temperature Temp2 and is maintained for the second preset time t2. During the cooling and keeping the wafer 10 warm, a reaction gas (including a precursor gas) is introduced into the reaction chamber 20 to perform thin film deposition on the surface of the wafer 10.

Specifically, the temperature of the wafer 10 is lowered by reducing the heating power of the heater, and the temperature of the edge of the wafer 10 is detected by the temperature sensor, so that the temperature of the edge of the wafer 10 is reduced from the first preset temperature Temp1 to the second preset temperature Temp2, and maintained at the second preset temperature Temp2 for the second preset time t2. Since the temperature of the edge of the wafer 10 will decrease before the temperature of the center of the wafer 10 when the wafer 10 is cooled (as shown in FIG8), a temperature gradient will be formed from the edge of the wafer 10 to the center of the wafer 10, that is, the temperature gradually increases from the edge of the wafer 10 to the center of the wafer 10 (as shown in FIG5 and FIG6). Since the temperature gradually increases from the edge of the wafer 10 to the center of the wafer 10, the temperature of the wafer 10 will directly affect the reaction rate, that is, the deposition rate of the thin film. The deposition rate of the thin film is high where the temperature is high, and the deposition rate of the thin film is low where the temperature is low. Therefore, affected by the uneven temperature distribution, the thickness of the deposited film gradually increases from the edge of the wafer 10 to the center of the wafer 10 (as shown in FIG7). Therefore, the thickness of the film gradually increases from the edge of the wafer 10 to the center of the wafer 10 due to the uneven temperature distribution, which can complement the thickness of the film gradually decreases from the edge of the wafer 10 to the center of the wafer 10 due to the uneven precursor concentration distribution. Through the combined effect of temperature and precursor concentration, the thickness uniformity of the final film is improved.

When the temperature of the edge of the wafer 10 reaches the second preset temperature Temp2, the temperature of the center of the wafer 10 has not reached the second preset temperature Temp2, and there is still a temperature difference between the edge of the wafer 10 and the center of the wafer 10. Therefore, it is necessary to keep the temperature of the edge of the wafer 10 at the second preset temperature Temp2 for a second preset time t2 so that the temperature of the center of the wafer 10 can also be reduced to the second preset temperature Temp2, so that the temperature of the entire wafer 10 is evenly distributed.

Step S20 and step S30 are repeated for a preset number of times. Each time the step is repeated, step S20 is performed first, and then step S30 is performed. A temperature gradient is formed from the edge of the wafer 10 to the center of the wafer 10 by cooling the temperature multiple times, so as to improve the thickness uniformity of the film finally formed by the uneven film thickness caused by the uneven final concentration. It should be noted that the preset number of times includes the first time. Exemplarily, the preset number of times can be 3 times. When the preset number of times is 3 times, the steps of the thin film deposition method are S10→S20→S30→S20→S30→S20→S30 in sequence.

In this embodiment, the first preset temperature Temp1, the second preset temperature Temp2 and the preset number of times are determined by a preset temperature field model formula;

The temperature field model formula is as follows:

b×(Temp1-Temp2)×number of loops/(2×mean)=Uf - Ui

Wherein, b is a coefficient. Affected by the thermal conductivity of the wafer 10, the gas flow rate in the reaction chamber 20, etc., the coefficient b at different positions of the reaction chamber is different and can be determined through experiments. Temp1 is the first preset temperature, Temp2 is the second preset temperature, the number of loops is the preset number, mean is the ideal average film thickness, Uf is the ideal uniformity parameter, and Ui is the initial uniformity parameter.

Among them, uniformity parameter = (maximum thickness within the chip - minimum thickness within the chip) / 2 / average film thickness within the chip. The average film thickness within the chip can be the average value of the film thickness measured at all film thickness measurement points within the chip (that is, on the wafer).

Specifically, the coefficient b, the ideal average film thickness mean, the ideal uniformity parameter Uf, and the initial uniformity parameter Ui can all be determined in advance by those skilled in the art. Then, the number of loops (i.e., the preset number of times) can be determined first. The number of loops is usually 2-5 times. Too many loops will lead to complex processes, reduce process stability and hardware service life; too few loops will reduce the effectiveness of adjusting the film thickness by forming a temperature gradient through cooling. Those skilled in the art can select a suitable number of loops through experience, and then determine the temperature difference between the first preset temperature Temp1 and the second preset temperature Temp2 through the above-mentioned temperature field model formula. Finally, the first preset temperature Temp1 and the second preset temperature Temp2 can be determined according to the reasonable temperature range of thin film deposition.

By using the first preset temperature Temp1, the second preset temperature Temp2 and the preset number of times determined based on the above formula, thin film deposition is performed using the above thin film deposition method, which can significantly improve the in-wafer uniformity of the deposited thin film.

It should be noted that, for the wafer 10 at different positions from the reaction chamber 20 , the corresponding first preset temperature Temp1 and the second preset temperature Temp2 may be different, and the coefficient b in the corresponding temperature field model formula may also be different.

In the embodiment of the present application, after step S20 and step S30 are repeated for a preset number of times, the thin film deposition method further includes the following steps:

S40 : within the third preset time t3 , maintaining the temperature of the edge of the wafer 10 at the second preset temperature Temp2 , while introducing reaction gas into the reaction chamber 20 to perform thin film deposition on the surface of the wafer 10 .

Step S40 is used to introduce reaction gas to make final adjustment of film thickness when the temperature of wafer 10 is low, so that the thickness of wafer 10 reaches the target thickness. The third preset time t3 can be determined according to the difference between the film thickness of wafer 10 before step S40 and the target film thickness.

Exemplarily, referring to FIG. 9 , in one embodiment of the present application, step S20 and step S30 are repeated three times, and then step S40 is performed, that is, the steps performed are S10→S20→S30→S20→S30→S20→S30→S40 in sequence.

Exemplarily, except for the first step S20, before each other step S20 (i.e., before the second and subsequent steps S20), the residual reaction gas in the reaction chamber 20 is exhausted to prevent the residual reaction gas in the reaction chamber 20 from affecting the concentration distribution of the precursor in the reaction chamber 20 and affecting the effect of adjusting the film thickness by forming a temperature gradient through cooling.

In one embodiment of the present application, the thin film deposited by the above steps is a silicon oxide thin film. For the wafers in the five regions in the reaction chamber, the first preset temperature Temp1, the second preset temperature Temp2 and the preset number are determined according to the following five model formulas:

Region 1 model formula: -218.6×(Temp1-Temp2)×number of loops/(2×6000)=1.6–3.6

Region 2 model formula: -147.5×(Temp1-Temp2)×number of loops/(2×6000)=1.6–2.7

Region 3 model formula: -177×(Temp1-Temp2)×number of loops/(2×6000)=1.1–2.3

Region 4 model formula: -75×((Temp1-Temp2)×number of loops/(2×6000)=1.1–1.5

Region 5 model formula: -60×(Temp1-Temp2)×number of loops/(2×6000)=1.3–1.5

That is, the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 1 are -218.6, 6000 (in angstroms, i.e. 600nm), 1.6, and 3.6, respectively; the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 2 are -147.5, 6000 (in angstroms, i.e. 600nm), 1.6, and 2.7, respectively; the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 3 are -147.5, 6000 (in angstroms, i.e. 600nm), 1.6, and 2.7, respectively. The initial uniformity parameter Ui is -177, 6000 (in angstroms, i.e. 600nm), 1.1, and 2.3 respectively; the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 4 are -75, 6000 (in angstroms, i.e. 600nm), 1.1, and 1.5 respectively; the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 5 are -60, 6000 (in angstroms, i.e. 600nm), 1.3, and 1.5 respectively.

The determined first preset temperature Temp1, the second preset temperature Temp2, the preset times and other parameters in the thin film deposition process are shown in Table 1 below:

Table 1 Parameter settings

In the related art, the method for depositing silicon oxide thin film is as follows: first, the temperature of the edge of the wafer is heated to the deposition temperature Temp3, and maintained at the deposition temperature Temp3, and then the reaction gas is introduced within the deposition time t4 to deposit the silicon oxide thin film (as shown in Figure 10). For the wafers in the five areas of the above reaction chamber (i.e., the wafers in areas 1-5), the deposition temperatures Temp3 are 689.1°C, 689.1°C, 680°C, 674°C, and 676°C, respectively, and the deposition time t4 is 160 minutes.

The average thickness and uniformity of the thin films deposited by the thin film deposition method of this embodiment and the deposition method of the related art are shown in Table 2 below:

Table 2 Average thickness and uniformity of the film

It can be determined without a doubt from Table 2 that the thickness uniformity of the thin film deposited by the thin film deposition method of this embodiment is significantly improved compared with the prior art.

Thin film deposition methods for silicon oxide:

1) The preset number of times can be controlled within 3 to 5 times. Too many cycles will lead to complex processes, reduce process stability and hardware life. Too few cycles will reduce the effectiveness of adjusting the film thickness by forming a temperature gradient through cooling.

2) The first preset temperature Temp1 and the second preset temperature Temp2 should be set to an average value of about 680 degrees Celsius, the temperature difference between the first preset temperature Temp1 and the second preset temperature Temp2 should be within 40 degrees Celsius (including 40°C), the first preset temperature Temp1 should not exceed 710 degrees Celsius, and the second preset temperature Temp2 should not be lower than 660 degrees Celsius. The specific difference is determined by the uniformity requirements. The greater the temperature difference, the stronger the improvement effect on uniformity. Conversely, the weaker it is.

3) The second preset time t2 is controlled within 5-10 minutes, and the cooling rate from the first preset temperature Temp1 to the second preset temperature Temp2 is controlled within 0.5°C/s-2°C/s.

In another embodiment of the present application, the thin film deposited by the above steps is a silicon nitride thin film. For wafers in five regions in the reaction chamber, the first preset temperature Temp1, the second preset temperature Temp2 and the preset number of times are determined according to the following five model formulas:

Region 1 model formula: -23.75×(Temp1-Temp2)×number of loops/(2×1500)=2.6–4.5

Region 2 model formula: -26.56×(Temp1-Temp2)×number of loops/(2×1500)=1.8–3.5

Region 3 model formula: -27.5×(Temp1-Temp2)×number of loops/(2×1500)=2–3.1

Region 4 model formula: -6.25×((Temp1-Temp2)×number of loops/(2×1500)=1.2–1.4

Region 5 model formula: -5×(Temp1-Temp2)×number of loops/(2×1500)=1.8–2.1

That is, the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 1 are -23.75, 1500 (in angstroms, i.e. 150nm), 2.6, and 4.5, respectively; the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 2 are -26.56, 1500 (in angstroms, i.e. 150nm), 1.8, and 3.5, respectively; the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 3 are -26.56, 1500 (in angstroms, i.e. 150nm), 1.8, and 3.5, respectively. The initial uniformity parameter Ui is -27.5, 1500 (in angstroms, i.e. 150nm), 2, and 3.1 respectively; the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 4 are -6.25, 1500 (in angstroms, i.e. 150nm), 1.2, and 1.4 respectively; the coefficient b, ideal average film thickness mean, ideal uniformity parameter Uf, and initial uniformity parameter Ui corresponding to region 5 are -5, 1500 (in angstroms, i.e. 150nm), 1.8, and 2.1 respectively.

The determined first preset temperature Temp1, the second preset temperature Temp2, the preset times and other parameters in the thin film deposition process are shown in Table 3 below:

Table 3 Parameter settings

In the related art, the method for depositing silicon nitride film is as follows: first, the temperature of the edge of the wafer is heated to the deposition temperature Temp3, and maintained at the deposition temperature Temp3, and then the reaction gas is introduced within the deposition time t4 to deposit the silicon nitride film (as shown in Figure 10). For the wafers in the five areas of the above reaction chamber (i.e., the wafers in areas 1-5), the deposition temperatures Temp3 are 765°C, 763°C, 760°C, 758°C, and 756°C, respectively, and the deposition time t4 is 50 minutes.

The average thickness and uniformity of the thin films deposited by the thin film deposition method of this embodiment and the deposition method of the related art are shown in Table 4 below:

Table 4 Average thickness and uniformity of the film

It can be determined without a doubt from Table 4 that the thickness uniformity of the thin film deposited by the thin film deposition method of this embodiment is significantly improved compared with the prior art.

Thin film deposition methods for silicon nitride:

1) The preset number of times can be controlled within 2-4 times. Too many cycles will lead to complex processes, reduce process stability and hardware life. Too few cycles will reduce the effectiveness of adjusting the film thickness by forming a temperature gradient through cooling.

2) The first preset temperature Temp1 and the second preset temperature Temp2 should be set to an average value of about 760 degrees Celsius, and the temperature difference between the first preset temperature Temp1 and the second preset temperature Temp2 should be controlled within 40 degrees Celsius (including 40 degrees Celsius). Preferably, the temperature difference between the first preset temperature Temp1 and the second preset temperature Temp2 is controlled within 30 degrees Celsius (including 30 degrees Celsius), the first preset temperature Temp1 does not exceed 790 degrees Celsius, and the second preset temperature Temp2 is not less than 740 degrees Celsius. The specific difference is determined by the uniformity requirement. The larger the temperature difference, the stronger the improvement effect on uniformity. Conversely, the weaker it is.

3) The second preset time t2 is controlled within 5-10 minutes, and the cooling rate from the first preset temperature Temp1 to the second preset temperature Temp2 is controlled within 1°C/s-2°C/s.

Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstract and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims.

Claims (10)

1. A method of depositing a thin film, comprising:

S10: feeding a wafer boat loaded with wafers into a reaction chamber;

s20: heating and preserving heat of a wafer in a reaction chamber so that the temperature of the edge of the wafer reaches a first preset temperature and the first preset time is maintained;

s30: cooling and preserving the temperature of the wafer so as to enable the temperature of the edge of the wafer to be reduced from the first preset temperature to the second preset temperature, and maintaining the second preset time, and introducing reaction gas into the reaction chamber in the process of cooling and preserving the temperature of the wafer so as to carry out film deposition on the surface of the wafer;

Wherein, step S20 and step S30 are repeated for a preset number of times.

2. The method for depositing a thin film according to claim 1, wherein,

The first preset temperature, the second preset temperature and the preset times are determined through a preset temperature field model formula;

The temperature field model formula is as follows:

b× (Temp 1-Temp 2) ×loop number/(2×mean) =uf-Ui

Wherein b is a coefficient, temp1 is the first preset temperature, temp2 is the second preset temperature, the loop number is the preset number of times, mean is an ideal average film thickness, uf is an ideal uniformity parameter, and Ui is an initial uniformity parameter.

3. The method for depositing a thin film according to claim 1 or 2, wherein,

The method further comprises the steps of:

S40: and in a third preset time, maintaining the temperature of the edge of the wafer at the second preset temperature, and simultaneously introducing reaction gas into the reaction chamber to perform film deposition on the surface of the wafer.

4. The method for depositing a thin film according to claim 1 or 2, wherein,

The reaction gas remaining in the reaction chamber is exhausted each time before the step S20 is performed except for the first performing step S20.

5. The method for depositing a thin film according to claim 1 or 2, wherein,

The film is a silicon oxide film.

6. The method for depositing a thin film according to claim 5, wherein,

The first preset temperature is less than or equal to 710 ℃;

The second preset temperature is greater than or equal to 660 ℃;

The difference between the first preset temperature and the second preset temperature is less than or equal to 40 ℃.

7. The method for depositing a thin film according to claim 5, wherein,

The preset times are 3-5 times;

the second preset time is 5-10 min.

8. The method for depositing a thin film according to claim 1 or 2, wherein,

The film is a silicon nitride film.

9. The method for depositing a thin film according to claim 8, wherein,

The first preset temperature is less than or equal to 790 ℃;

the second preset temperature is greater than or equal to 740 ℃;

The difference between the first preset temperature and the second preset temperature is less than or equal to 30 ℃.

10. The method for depositing a thin film according to claim 8, wherein,

The preset times are 2-4 times;

the second preset time is 5-10 min.