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WO2003060434A1 - Capteur thermique et son procédé de fabrication - Google Patents

Capteur thermique et son procédé de fabrication Download PDF

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Publication number
WO2003060434A1
WO2003060434A1 PCT/JP2002/000043 JP0200043W WO03060434A1 WO 2003060434 A1 WO2003060434 A1 WO 2003060434A1 JP 0200043 W JP0200043 W JP 0200043W WO 03060434 A1 WO03060434 A1 WO 03060434A1
Authority
WO
WIPO (PCT)
Prior art keywords
wiring
substrate
thermal sensor
film
input
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2002/000043
Other languages
English (en)
Japanese (ja)
Inventor
Naoki Yutani
Tsukasa Matsuura
Kazuhiko Tsutsumi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to PCT/JP2002/000043 priority Critical patent/WO2003060434A1/fr
Priority to JP2003536317A priority patent/JPWO2003060434A1/ja
Publication of WO2003060434A1 publication Critical patent/WO2003060434A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
    • G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
    • G01F1/692—Thin-film arrangements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/6845—Micromachined devices

Definitions

  • the present invention relates to a thermal sensor that measures the amount of heat loss generated by a heating element formed of a thin film resistor formed on a substrate surface using a thermal detection element.
  • FIG. 14 is an external view of an element schematically showing a part of a flow rate detecting element which is one of the thermal sensors disclosed in, for example, Japanese Patent Application Laid-Open No. 11-28145.
  • FIG. 15 is a cross-sectional view including the mounting form of the thermal sensor of FIG. '
  • reference numeral 101 denotes a flat substrate constituting a thermal sensor element 100'0 cut out of a silicon wafer, for example, and 107 and 108 are formed on one surface of the flat substrate 1.
  • the insulating support film is made of, for example, a silicon nitride film.
  • the silicon nitride film 108 also serves as a protective film.
  • a thermal resistor film 102 is formed between the silicon nitride films 107 and 108.
  • the heat-sensitive resistor film 102 corresponds to a heat-generating portion used for a heat-generating resistor and a temperature-measuring resistor, and is made of, for example, platinum.
  • a diaphragm 105 composed of silicon nitride films 107 and 108 is formed.
  • Reference numeral 103 denotes a wiring connecting the heat-sensitive resistive film 102 and the input / output pad 150, and is formed of, for example, the same film as the heat-sensitive resistive film 102.
  • Reference numeral 151 denotes a thermal sensor package, for example, epoxy resin. The substrate 101 of the thermal sensor element 1000 is fixed to the package 151 with an adhesive agent 155.
  • 15 3 is an external I / O lead
  • 15 4 is a wire bond material for electrically connecting the I / O pad 150 and the external I / O lead 15 3, for example, a 25 m diameter gold (Au) wire It is.
  • Reference numeral 152 denotes a cover of the package 151, which covers the wire bond 1554.
  • a silicon nitride film 107 having a thickness of about l ⁇ m is formed on a silicon wafer 101 having a thickness of about 400 / m, which is a plate-like base material, by a method such as a sputtering method.
  • a heat-sensitive resistor film 102 made of, for example, 0.2 ⁇ m-thick white gold is formed thereon by a vapor deposition method, a sputtering method, or the like. After that, anneal for several hours at about 600 ° C for stabilization.
  • This platinum film 102 is patterned using a photoengraving method, an etching method, a dry etching method, or the like, thereby forming a wiring with the heating portion 102 having a pattern as shown in FIG. 103 is formed.
  • a silicon nitride film 108 having a thickness of about 0.8 ⁇ m is formed as a protective film by a sputtering method or the like.
  • a part of the back surface protective film 108 on the wiring 103 is etched using photolithography or the like to form an input / output unit 150.
  • the diaphragm 105 composed of the silicon nitride films 107 and 108 is formed by photolithography on the surface opposite to the surface on which the support films 107 and 108 are disposed. It is formed by performing desired patterning, for example, by performing alkali etching or the like.
  • the thermal sensor element created in this way is fixed to the package 15 1 with adhesive 15 5, and the thermal sensor element input / output pad 150 and external input / output lead 15 3 are connected with a wire bond 15 4 I do. Finally, the package lid 15 2 is bonded and fixed to protect the wire-to-bond portion. Thus, a thermal sensor on which the elements are mounted is completed.
  • Heat generation and temperature measurement may be composed of separate resistors. There is also a reading method in which the current value is increased by an amount corresponding to an increase in the amount of heat taken away due to an increase in the flow rate so that the temperature of the heat generating portion is constantly kept constant, and the change in the control current is used as a signal output. is there. Further, since the output varies depending on the outside air temperature, an outside air temperature sensor for temperature correction may be formed on the substrate 101 in some cases.
  • the package 151 is designed in a wing shape so that there is no turbulence in the air flow near the detection unit 102 of the thermal sensor, and is designed to have no irregularities around the detection unit. Therefore, the distance X (shown in Fig. 15) from the detector to the package lid 152 needs to be sufficiently large so that the air flow is not disturbed, and it is desirable that it is approximately 2 mm or more.
  • the signal output unit 150 is formed on the same surface as the detection unit 102 of the substrate 101 constituting the sensor element, The output section had to be sufficiently separated from the detection section so as not to affect it, and it was necessary to make the wiring area from the detection section to the output section long.
  • problems such as an increase in the element size and an increase in the manufacturing cost of the element, and also in the mounting, the package structure is complicated and large, and the number of assembling steps and component costs increase.
  • the present invention has been made to solve the above problems, and has as its object to obtain a thermal sensor having a small and simple mounting structure. Disclosure of the invention
  • the thermal sensor according to the present invention is a heat sensor comprising: an insulating support film disposed on a first surface of a flat substrate having a thickness of 150 zm or more; And a body, and the diaphragm is formed by partially removing the base material below the region where the heating element is formed. Is connected to an input / output wiring portion formed on the second surface of the substrate via a through wiring formed so as to penetrate from the first surface to the second surface of the substrate. As a result, it is possible to connect the input / output wiring of each element of the thermal sensor formed on the surface of the substrate to the wiring on the back surface of the substrate using through wiring.
  • the input / output section which had to be formed sufficiently apart, can now be formed on the back side of the board.
  • the output can be taken out from the surface opposite to the detection surface, the size of the mounting form can be reduced and the cost can be reduced.
  • the thickness of the board is 150 m or more and the distance from the back of the diaphragm of the heating element to the mounting board is 150 jum or more, the heat loss from the back of the diaphragm can be ignored for the output signal. This has the effect of improving signal accuracy and reducing power consumption.
  • the thermal insulation between the substrate and the heating element is reduced. Since the distance from the heating element to the opening of the substrate can be reduced, the size of the element can be reduced, and the manufacturing cost can be reduced.
  • conductive bumps are formed on the input / output wiring part on the second surface of the board, so that conductive bumps can be connected to the wiring on the back side to enable bump connection to packages and circuit boards.
  • the mounting structure is small This has the effect of simplifying and reducing the number of assembly steps and the number of mounted components, thus reducing costs.
  • the through wiring is silicon containing a high concentration of P-type or N-type impurities, and an insulating layer made of silicon oxide is provided around the through wiring.
  • the periphery of a part of the silicon substrate containing high concentration of P-type or N-type impurities is oxidized in a ring shape to form an insulating layer, and the part surrounded by the insulating layer is used as a through-wiring.
  • a thermal sensor can be formed using the substrate on which the thermal sensor is formed, and a thermal sensor having a back surface output can be easily obtained, which has the effect of reducing manufacturing costs.
  • a first portion of the substrate may be penetrated to a partial region of the wiring formed on the first surface of the substrate.
  • a through-hole is opened from the surface of No. 2, and a droplet of molten metal is selectively introduced into the through-hole, and the droplet is embedded in the through-hole and hardened to form the above-mentioned through wiring. It was made by embedding and hardening the conductive paste droplets into the through-holes by the ink jet method. There is an effect that a thermal sensor with a back side output can be obtained which can be easily buried in the device and which does not require a manufacturing cost.
  • silicon containing a high concentration of P-type or N-type impurities is used as a substrate, and a partial region of the silicon substrate is cylindrical.
  • the substrate is oxidized from the first surface to the second surface of the substrate to form a cylindrical insulating layer, and the portion surrounded by the insulating layer is used as the through wiring, so that the through wiring is formed in advance. Since the thermal sensor is formed using the substrate, a thermal sensor having a back side output can be easily obtained, and the production cost can be reduced.
  • FIG. 1 is a schematic view showing an appearance of a thermal sensor (flow sensor) according to a first embodiment of the present invention
  • FIG. 2 is a cross-sectional view showing a mounting form of the thermal sensor.
  • FIG. 3 is a schematic view of a sensor element different from FIG.
  • FIG. 4 is a schematic top view of an element portion of a thermal sensor according to a second embodiment of the present invention, showing a layout of a heating element and a through wiring.
  • FIG. 5 is a schematic diagram showing an appearance of an element portion of a thermal sensor according to a third embodiment of the present invention.
  • FIG. 6 is a cross-sectional view showing a mounting form of the thermal sensor according to the fourth embodiment of the present invention, showing a specific example of the mounting form of the thermal sensor shown in the first to third embodiments. is there.
  • FIG. 5 is a cross-sectional view showing a mounting mode of the thermal sensor according to the fifth embodiment of the present invention.
  • bump connection is shown. This is an example.
  • FIG. 8 shows the steps of manufacturing a thermal sensor according to the sixth embodiment of the present invention in the order of (a) to (el) to (e2), particularly for showing the process of forming through wiring.
  • FIG. 9 is a process diagram showing an example in which a through hole and a diaphragm are formed by a wet etching method different from the plasma etching of FIG.
  • FIGS. 10 and 11 are views for explaining a manufacturing process of a thermal sensor according to a seventh embodiment of the present invention, and FIG. 10 is a part for explaining the formation of a through hole.
  • FIG. 11 is a perspective view showing the process of forming through wirings in the order of (a) to (el) to (e2) using the through holes formed in FIG.
  • FIG. 12 is a schematic view showing an appearance of an element portion of a thermal sensor (pressure sensor) according to an eighth embodiment of the present invention, and FIG. 13 is a cross-sectional view showing a mounting form of the sensor.
  • FIG. 14 is an external view of a sensor element showing the appearance of a conventional thermal sensor.
  • FIG. 15 is a schematic cross-sectional view including a mounting form of the thermal sensor of FIG. BEST MODE FOR CARRYING OUT THE INVENTION
  • FIG. 1 is an external view of an element when a thermal sensor according to an embodiment of the present invention is used as a gas flow sensor.
  • FIG. 2 is a cross-sectional view showing a mounting form of the flow sensor shown in FIG.
  • reference numeral 1 denotes a plate-like substrate for forming a thermal sensor element 100 cut out of, for example, a silicon wafer, and has a thickness of 150 / m or more.
  • Reference numerals 7 and 8 denote insulating support films formed on one surface of the flat substrate 1 and are made of, for example, a silicon nitride film.
  • the silicon nitride film 8 also serves as a protective film.
  • the thermal resistor film 2 is formed between the silicon nitride films 7 and 8.
  • the heat-sensitive resistor film 2 corresponds to a heat-generating portion used for a heat-generating resistor and a temperature-measuring resistor, and is made of, for example, platinum (Pt).
  • the lower silicon substrate 1 including the periphery of the thermal resistor film 2 is removed so that the heat generated in the thermal resistor film 2 does not escape to the silicon substrate 1 and the temperature of the heat generating portion rises, and the cavity 1a is removed. None, a diaphragm 5 composed of silicon nitride films 7 and 8 is formed in that portion.
  • Reference numeral 3 denotes a wiring on the front side that connects the thermal resistance film 2 and the through wiring 4, and is formed of, for example, a film of the same material as the thermal resistance film 2.
  • Reference numeral 6 denotes an insulating layer for electrically insulating the through wiring 4 from the substrate 1.
  • Reference numeral 9 denotes an insulating layer for electrically insulating the wiring layer 10 on the back surface of the substrate from the substrate 1 and is, for example, a silicon nitride film.
  • Reference numeral 11 denotes a backside protective film, for example, a silicon nitride film.
  • Reference numeral 12 denotes an opening of the backside protective film 11, which is a back surface input / output pad of the thermal sensor.
  • 21 is a thermal sensor package, for example, epoxy resin. The thermal sensor element 100 is fixed to the package 21 with an adhesive 18.
  • I / O lead 23 is an external I / O lead
  • 24 is an electrical connection between I / O pad 12 and external I / O lead 23
  • a gold (Au) wire having a diameter of 25 ⁇ m is used as a bonding material.
  • Reference numeral 22 denotes a lid of the package 21 covering the wire bond 24, which is made of epoxy resin similarly to the package 21.
  • the arrow Y in the figure indicates the direction of the airflow.
  • a silicon nitride film 7 having a thickness of, for example, 1 / m is formed on a silicon wafer 1 having a thickness of about 400 m, which is a plate-like base material, by a method such as a sputtering method.
  • a heat-sensitive resistor film 2 made of 2 zm platinum or the like is formed by a vapor deposition method, a sputtering method, or the like. After that, anneal for several hours at about 600 ° C for stabilization.
  • the platinum film 2 is subjected to patterning using a photoengraving method, a wet etching method, a dry etching method, or the like, thereby forming a heating portion 2 and a surface wiring 3 having a pattern as shown in FIG. You.
  • a silicon nitride film 8 having a thickness of about 0.8 ⁇ m is formed as a protective film by a sputtering method or the like.
  • the through wiring 4 is formed by being electrically insulated from the substrate 1 by the insulating layer 6.
  • the surface wiring 3 is electrically connected to the through wiring at the opening of the support film 7.
  • the back wiring 10 is formed, for example, as follows.
  • a silicon nitride film 9 having a thickness of about 0.5 m is formed on the back surface by a sputtering method or the like.
  • an AlSi film for example, is formed as a wiring film on the back surface by a spatula method or the like.
  • the backside wiring film is subjected to desired patterning using photolithography or the like and etched to form backside wiring 10.
  • a silicon nitride film having a thickness of about 0.8 jm is formed as a back surface protective film 11 by a sputtering method or the like.
  • a part of the back surface protection film 11 on the back surface wiring 10 is etched using a photolithography method or the like to form an output portion 12.
  • the through wiring 4 and the back wiring 10 enable the input and output of various sensors such as a heating section and a signal detection section formed on the front surface to be taken out from the back output section 12.
  • the flam 5 is formed by subjecting the surface opposite to the surface on which the support films 7 and 8 are arranged to a desired patterning using a photolithography method or the like, for example, by applying alkali etching or the like. You.
  • the thermal sensor element 100 created in this way is fixed to the package 21 with an adhesive 18, and the thermal sensor element I / O pad 12 is connected to the external I / O lead 23 with a wire bond 24. . Finally, the lid 22 of the package is bonded and fixed to protect the wire bond portion.
  • the thermal sensor that measures the flow rate of the gas measures the flow rate by using the fact that the amount of heat taken by the gas flowing over the heating section 2 of the sensor changes according to the flow rate. Therefore, the amount of heat lost from the back surface of the diaphragm 5 to the package 21 must be negligible with respect to the amount of heat taken from the front surface of the diaphragm 5 by the gas flow. This heat loss can be reduced by increasing the distance L (in FIG. 2) from the back side of the diaphragm 5 to the circuit board.
  • FIG. 3 shows an external view of the sensor element according to the present embodiment.
  • the direction Y of the airflow matches the direction of the wiring outlet.
  • the upstream and downstream of the detection unit with respect to the airflow direction Y The side could not arrange the input / output unit.
  • the through wire 4 can be arranged also in the direction of the air flow as shown in FIG. 3 and the element size is reduced. can do.
  • Example 2
  • FIG. 4 is a schematic top view of a thermal sensor according to another embodiment of the present invention, showing a layout of a heat generating body 2, a through wiring 4, and the like.
  • Reference numeral 26 denotes a temperature sensor element arranged on the sensor element substrate 1.
  • a plurality of heating elements 2 are arranged in the diaphragm 5.
  • the wiring between the heating element 2 and the temperature sensor 26 can be taken out from the back surface by the through wiring 4.
  • the through wirings may be arranged on the upper, lower, left and right around the diaphragm 5, may be arranged on one side only, or may be arranged at any position on the substrate 1 on which the sensor element is formed. Therefore, it is possible to select an arrangement in which the size of the element is minimized and the output to the back surface is easily taken out.
  • FIG. 5 is an external view of a thermal sensor according to another embodiment of the present invention.
  • reference numeral 19 denotes an opening from which not only the substrate 1 but also a part of the diaphragm 5 in FIG. 3 is removed, and the heating element 2 is held by a bridge-shaped support film 27.
  • the thermal resistance in the horizontal direction can be increased as compared with the diaphragm structure, so that the size of the cavity 1a formed in the substrate 1 can be reduced, so that the element size can be reduced.
  • Example 4
  • FIG. 6 is a cross-sectional view showing a mounting mode of a thermal sensor according to another embodiment of the present invention.
  • 1 5 connects the I / O pad 1 2 on the back and the external I / O lead 2 3
  • the bumps are connected by air and are formed of, for example, molten metal such as solder or gold.
  • Reference numeral 18 denotes a sealing material such as an epoxy resin for fixing and sealing the element and the circuit board. Other configurations are the same as those in FIG. 2 of the first embodiment.
  • FIG. 2 of the first embodiment an example is described in which the input / output pad 12 on the back surface and the external input / output lead 23 of the package 21 are connected by the wire bond 24.
  • Use bumps instead of.
  • a mounting method of the thermal sensor of FIG. 6 will be described.
  • a gold bump having a height of several tens / m is formed on one or both of the input / output pad 12 of the thermal sensor element and the pad of the external input / output lead 23 of the package 21.
  • the gold bump is fixed to the individual pads 12 and 23a (the pad portions of the external input / output leads 23) by pressing and fixing the gold or using a wire bonder. Formed in the groove.
  • a molten metal such as solder
  • the bump 15 it is prepared as follows. For example, a solder bump of several tens of meters in size is formed on both or one of the input / output pad 12 of the thermal sensor element and the pad 23 a of the external input / output lead 23 of the package 21.
  • the thermal sensor element is aligned so that the pad 12 is directly above the pad 23 of the external input / output lead 23, then heated to a temperature at which the solder melts, and the pads are electrically connected with solder bumps.
  • a sealing material 18 such as an epoxy resin is put between the element and the package and hardened.
  • the use of a bump structure simplifies the structure of the package, and also allows for downsizing.
  • the above mounting method is an alternative to the mounting method of the first embodiment, and is also applicable to the second and third embodiments.
  • Embodiment 5 is an alternative to the mounting method of the first embodiment, and is also applicable to the second and third embodiments. Embodiment 5.
  • FIG. 7 is a sectional view showing a mounting mode of a thermal sensor according to another embodiment of the present invention using bump connection.
  • a wiring board 13 connects the thermal sensor element 100 and the signal processing circuit element 1, and is formed of, for example, glass epoxy resin.
  • Reference numeral 14 denotes a wiring layer of the wiring board 13 which is electrically connected to the input / output pads 12 of the thermal sensor by bumps 15 and connected to the input / output pads 17 a of the signal processing circuit element 17. Even bumps 16 are connected.
  • the bumps 15 and 16 are made of, for example, molten metal such as solder or gold.
  • Reference numeral 18 denotes a sealing material such as an epoxy resin for fixing and sealing the element and the circuit board. 25 is a mold resin.
  • the method of connecting the bumps is the same as in the case of FIG. 6 of the fourth embodiment.
  • the sealing material 18 such as epoxy resin is used to connect the sensor element 100 and the signal. It is put between the processing circuit element 1 ⁇ and the circuit board 13 to cure. Finally, the entire surface except the detection surface is sealed with mold resin 25.
  • This structure enables downsizing including the signal processing circuit. Needless to say, the above mounting method can be applied to any of the thermal sensors of the first to third embodiments. Embodiment 6.
  • a through hole is formed in a substrate, an insulating film is formed on the inner wall of the hole, and then a metal is filled in the through hole by plating.
  • the thermal sensor requires a substrate thickness of more than 150 zm, so the length of the through wiring passing through this substrate is also more than 150 m. Considering the process, the smaller the substrate thickness, the better.
  • 150 m or more is required. Therefore, it is difficult with the conventional method, and a special method is required for forming the through wiring.
  • the aspect ratio (hole length / diameter) of the through hole is relatively small at 4, so normal plasma anisotropy is used.
  • Through holes can be easily formed by etching.
  • trying to completely fill a large through-hole with metal by the plating method increases the working time and material cost. If the through hole cannot be completely filled, a concave part will be formed on the back surface, making it difficult to perform photolithography after the through wiring.
  • the through hole is made as small as about 4 / m in diameter, for example, it becomes possible to cover the surface of the through hole with a conductive material by a general metal film forming method such as a CVD method or a plating method. Therefore, it is difficult to embed the conductive material uniformly over the entire length of the through hole. At this large aspect ratio, etching of the through hole becomes difficult.
  • FIGS. 8 (a) to (el, 2) are diagrams for explaining a method of forming a through wiring according to one embodiment of the present invention. Hereinafter, a method of forming the through wiring will be described with reference to the drawings.
  • a silicon nitride film 7 having a thickness of, for example, about 1 is formed on a plate-like base material silicon wafer 1 having a thickness of about 400 ⁇ m by a method such as a sputtering method.
  • a contact hole 30 is formed by opening a part of the silicon nitride film 7 in a region where a through wiring is to be formed.
  • the surface wiring 3 is electrically connected to the through wiring via the contact hole 30.
  • a heat-sensitive resistor film 2 made of platinum or the like having a thickness of 0.2 zm is formed by an evaporation method, a sputtering method, or the like.
  • This platinum film 2 is patterned by photolithography, wet etching, dry etching, or the like to form a heating portion (thermosensitive resistive film) 2 and a surface wiring 3 having the pattern shown in FIG. You.
  • silicon nitride with a thickness of about 0.8 / m
  • the film 8 is formed by a sputtering method or the like.
  • a desired patterning is performed on the surface opposite to the surface on which the support films 7 and 8 are disposed by using a photoengraving method or the like, for example, the silicon film 7 is exposed by reactive ion beam etching.
  • a through hole 31 having a size of about 100 m is formed. At this time, etching is performed until the surface wiring 3 of the contact hole portion 30 is exposed. Since the aspect ratio of the through hole is as small as about 4, the through hole can be easily formed by ordinary plasma anisotropic etching.
  • an insulating film 32 such as a silicon nitride film is formed on the wall surface of the through hole 31 and the back surface of the substrate 1 by a sputtering method or a CVD method, for example.
  • the insulating film 32 in the contact hole 30 is removed.
  • the contact hole 30 formed before the formation of the surface wiring may be formed by etching the insulating film 7 from the side of the through hole 31 when part of the insulating film 32 is removed.
  • a droplet 33 of molten metal such as solder having a diameter of about 70 zm is selectively driven into the through-hole 31 by using, for example, an ink jet method, and the through-hole is formed.
  • the molten metal is buried up to the front surface of the back surface by adjusting the number of droplets to be injected into the through hole, and a through wiring 34 shown in the figure is formed.
  • the droplets may be stored in the through-holes while being melted, and then cooled and cured.
  • the substrate 1 may be heated and melted and hardened after the appropriate amount of droplets are injected without heating.
  • an AlSi film is formed as a wiring film on the back surface by a sputtering method or the like.
  • the back wiring film is subjected to a desired patterning using a photoengraving method or the like and etched to form a back wiring 10.
  • a part of the back surface protective film 11 on the back surface wiring 10 is etched using a photolithography method or the like to form an output part 12.
  • the through wiring 34 and the back wiring 10 allow the input and output of various sensors such as a heating section and a signal detection section formed on the front surface to be extracted from the back output section 12. If the connection bump 35 is formed directly on the through wiring portion as shown in (e2) in the figure, the back wiring 10 becomes unnecessary.
  • the substrate 1 is etched from the side where the back wiring is formed, and the portion where the thermal resistor film 2 is formed is finished into the diaphragm portion 5.
  • solder is used as the molten metal, but this may be another molten metal.
  • FIG. 9 shows a schematic cross-sectional view of a process in which etching of the through hole and the substrate of the diaphragm portion are simultaneously performed by wet etching.
  • a silicon nitride film 7 having a thickness of about 1 m is formed on a plate-like base material silicon wafer 1 having a thickness of about 400 m by a method such as a sputtering method.
  • a contact hole 30 is formed by opening a part of the silicon nitride film 7 in a region where a through wiring is to be formed.
  • the contact hole 30 electrically connects the surface wiring 3 to the through wiring.
  • a heat-sensitive resistor film 2 made of, for example, platinum and having a thickness of 0.2 zm is formed by an evaporation method, a sputtering method, or the like. After that, anneal for several hours at about 600 ° C for stabilization.
  • the platinum film 2 is patterned by photolithography, wet etching, dry etching, or the like to form a heating portion (thermosensitive resistor film) 2 and a surface wiring 3 having a pattern as shown in FIG. It is.
  • a silicon nitride film 8 is formed by a sputtering method or the like.
  • a desired pattern is formed on the surface opposite to the surface on which the support films 7 and 8 are arranged, using a photoengraving method or the like so that the portion between the through hole and the diaphragm is etched.
  • anisotropic etching of Si is performed by a wet etching method using an alkaline solution such as KOH until the silicon nitride film 7 is exposed, and a through hole 31 having a size of about 600 ⁇ m and a diaphragm 5 are formed.
  • the surface wiring 3 in the contact hole 30 is also exposed.
  • the etching stops at the (111) plane, so a slope of 54.7 degrees is formed as shown in the figure. Therefore, if the opening on the back side of the through hole is designed to be 600 zm square, the opening on the front side will be 34 zm square.
  • an insulating film 32 such as a silicon nitride film is formed on the wall surface of the through hole 31 and the back surface of the substrate 1 by a sputtering method or a CVD method. Then, the insulating film 32 of the contact hole 30 and the diaphragm 5 is removed. As described in FIG. 8B, the contact hole 30 formed before the formation of the surface wiring may be formed by simultaneously etching the insulating film 32 and the insulating film 7 at this time.
  • a droplet 33 of a molten metal such as a solder having a diameter of about 70 m, for example, is selectively driven into the through-hole 31 by using, for example, an ink jet method. Fill through hole 32 with molten metal.
  • the number of droplets to be injected into the through hole is adjusted to fill the molten metal up to the surface of the back surface to form the through wiring 34.
  • the substrate 1 is removed.
  • the substrate may be heated and stored in a through-hole with the molten metal droplets being melted, then cooled and stiffened, or the substrate 1 may be heated after the appropriate amount of droplets are injected without heating. It may be melted and hardened.
  • an AlSi film is formed as a wiring film on the back surface by a sputtering method or the like.
  • the backside wiring film can be made to the desired Perform evening etching to form backside wiring 10.
  • a silicon nitride film having a thickness of about 0.8 m is formed as a back surface protective film 11 by a sputtering method or the like.
  • a part of the back surface protective film 11 on the back surface wiring 10 is etched using a photolithography method or the like to form an output part 12.
  • the through wiring 4 and the back wiring 10 allow the input and output of various sensors formed on the front surface, such as a heating section and a signal detection section, to be extracted from the back output section 12.
  • connection bump 35 is formed directly on the through wiring portion as shown in (e2) in the figure, the back wiring 10 becomes unnecessary.
  • FIG. 10 and FIG. 11 are diagrams for explaining an example of another method for forming a through wiring according to the embodiment of the present invention.
  • FIG. 10 is a perspective view
  • FIG. 11 is a process diagram according to a forming procedure.
  • the forming method will be described with reference to the drawings.
  • the base material 1 use a silicon wafer containing a high concentration of N-type or: P-type impurities.
  • an array of fine through holes 41 with a width of about 5 ⁇ m surrounding the through wiring formation area of a silicon wafer 1 of about 400 m thickness, which is a plate-shaped substrate.
  • the pitch of the arrangement of the fine through holes 41 is set so that the silicon wall between the adjacent fine through holes becomes thin.
  • the Si wall is about 2 zm.
  • These fine through-holes can be formed, for example, by dry etching of silicon using ICP-R (E (Inductively Coupled Plasma Reaction Ion Etching) or chemical etching of electoric mouth using electrochemical reaction between silicon and hydrofluoric acid aqueous solution. Formed in a simple manner.
  • the periphery of the fine through-hole 41 is oxidized by oxidizing the substrate 1 in an oxygen atmosphere at 900 ° C. or more. Here, the oxidized substrate surface is removed, but may be left as necessary.
  • the silicon wall between adjacent fine through-holes is completely oxidized as shown in (b) in the figure, and a donor-shaped insulating layer 42 of silicon oxidized film is formed.
  • the portion of the base material 1 remaining without being oxidized and surrounded by the insulating layer 42 becomes the through wiring 43.
  • the through wiring 43 is formed of the substrate 1, but the other part of the element substrate and the through wiring 43 are electrically separated by the insulating layer 42. If the wiring on the front side and the wiring on the back side of the substrate 1 are connected to the through wiring 43, the input / output of the element formed on the front side can be taken out from the back side.
  • the resistance of this through wiring is determined by the resistance of the substrate 1.
  • the resistance of the through wiring becomes 0.5 ⁇ . This is sufficiently smaller than the resistance value of the heat-sensitive resistive film of several hundreds to several hundred thousand ohms.
  • FIG. 10A a substrate 1 on which a through wiring 43 is formed by the method shown in FIG. 10 is prepared.
  • a silicon nitride film 7 having a thickness of about 1 // m, for example, is formed on the surface of the substrate 1 by a method such as a sputtering method.
  • a contact hole 30 is formed by opening the silicon film 7 on the through wiring 43.
  • the surface wiring 3 is electrically connected to the through wiring 43 via the contact hole 30.
  • a heat-sensitive resistor film 2 made of, for example, platinum having a thickness of 0.2 m is formed by an evaporation method, a sputtering method, or the like. After that, anneal for several hours at about 600 ° C for stabilization.
  • This platinum film 2 is patterned by photolithography, wet etching, dry etching, or the like to form a heat generating portion 2 and a surface wiring 3 having a pattern as shown in FIG.
  • a silicon nitride film 8 having a thickness of about 0.8 / m is formed as a protective film on the platinum films 2 and 3 by a sputtering method or the like. To achieve.
  • a silicon nitride film 9 having a thickness of about 0.5 m is formed on the back surface by a sputtering method or the like, and a part of the insulating film 9 in the portion of the through wiring 43 is formed. 4. Open 3 by photolithography or the like.
  • an AlSi film for example, is formed as a backside wiring film by a sputtering method or the like.
  • the back wiring film is subjected to desired patterning by photolithography or the like and etched to form the back wiring 10.
  • a silicon nitride film having a thickness of about 0.8 ⁇ m is formed as a back surface protective film 11 by a sputtering method or the like.
  • a part of the back surface protection film 11 on the back surface wiring 10 is etched by photolithography or the like to form an output part 12.
  • the substrate 1 is etched from the back surface to form the diaphragm 5.
  • various sensors such as the heat generating portion and the signal detecting portion formed on the front surface by the through wiring 43 and the rear surface wiring 10 can be taken out from the rear surface output portion 12.
  • connection bumps were provided as shown in FIGS. 8 and 9 (e2) in the sixth embodiment. It may be used as an input / output unit.
  • the flow sensor has been described as an example of a thermal sensor.
  • another thermal sensor for example, a thermal pressure sensor in which a pressure receiving diaphragm and a thermal sensor are combined may be used.
  • FIG. 12 is a schematic view showing an appearance when the thermal sensor of the present invention is used as a pressure sensor
  • FIG. 13 is a cross-sectional view showing a mounting form.
  • FIG. 13 shows a mounting mode of the pressure sensor when the same bump connection as the mounting mode of the flow sensor shown in FIG. 7 of the fifth embodiment is used.
  • the structure and manufacturing method of the thermal sensor element 100 can be the same as those of the thermal flow sensor shown in the first to seventh embodiments.
  • Reference numeral 47 denotes a spacer that defines a gap of several tens / zm between the diaphragm 46 and the thermal sensor element 100, and is formed of, for example, a polyimide resin.
  • the upper part of the spacer 47 is a pressure receiving part, and the lower part is a sensor part, which constitutes a pressure sensor.
  • the flow sensor measures the flow rate using the fact that the amount of heat taken by the gas flowing over the heating section 2 of the sensor changes according to the flow rate, whereas the pressure sensor measures the flow rate using the center of the diaphragm 46 and the heat-sensitive resistance film 2.
  • the pressure is measured by using the fact that the distance from the formed heat generating portion changes according to the pressure (P in the figure), and the amount of heat taken from the heat generating portion to the diaphragm 46 changes accordingly.
  • a wiring board 13 connects the thermal sensor element 100 and the signal processing circuit element 17 and is made of, for example, glass epoxy resin.
  • Reference numeral 14 denotes a wiring layer of the wiring board 13 formed on both sides of the wiring board 13, and is electrically connected to the input / output pad 12 of the thermal sensor by bumps 15.
  • the bumps 15 and 16 are formed of, for example, molten metal such as solder or gold.
  • Reference numeral 18 denotes a sealing material such as epoxy resin for fixing and sealing the element and the circuit board.
  • the method of connecting the bumps is the same as in the case of FIG. 6 of the fourth embodiment.
  • the sealing material 18 such as epoxy resin is used to connect the sensor element 100 and the signal. It is inserted between the processing circuit element 17 and the circuit board 13 and hardened.
  • the diaphragm housing 45 and the sensor element 100 are bonded together with an adhesive or the like at the spacer 47 or the circuit board 13 is pressed toward the diaphragm housing 45 with a panel or the like. Attach and fix.
  • the thermal sensor according to the present invention is used for a flow sensor and a pressure sensor for measuring an intake air amount of an internal combustion engine for a vehicle or the like.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)

Abstract

La présente invention concerne un capteur thermique dans lequel des éléments chauffants (2) sont disposés à la surface d'un substrat plan (1) d'au moins 150 νm d'épaisseur et un câblage (3) destiné à un signal de sortie et sont reliés électriquement à travers un câblage (4) traversant depuis la surface jusqu'à une face arrière du substrat (3) et reliés en outre électriquement à une portion de câblage d'entrée/sortie (12) constitué sur la face arrière du substrat. Etant donné que la portion d'entrée/sortie qui doit être suffisamment séparée de la portion de détection à la surface du substrat dans l'art antérieur peut être formée sur la face arrière du substrat et peut être disposée librement par rapport à la partie de détection, on peut réduire la taille de l'élément et les coûts de fabrication également.
PCT/JP2002/000043 2002-01-09 2002-01-09 Capteur thermique et son procédé de fabrication Ceased WO2003060434A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/JP2002/000043 WO2003060434A1 (fr) 2002-01-09 2002-01-09 Capteur thermique et son procédé de fabrication
JP2003536317A JPWO2003060434A1 (ja) 2002-01-09 2002-01-09 熱式センサ及びその製造方法

Applications Claiming Priority (1)

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PCT/JP2002/000043 WO2003060434A1 (fr) 2002-01-09 2002-01-09 Capteur thermique et son procédé de fabrication

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WO2003060434A1 true WO2003060434A1 (fr) 2003-07-24

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007212199A (ja) * 2006-02-07 2007-08-23 Yamatake Corp センサのパッケージ構造及びこれを有するフローセンサ
JP2010230312A (ja) * 2009-03-25 2010-10-14 Fujikura Ltd 半導体センサの製造方法及び半導体センサ
JP2011048165A (ja) * 2009-08-27 2011-03-10 Hitachi Consumer Electronics Co Ltd 投写型表示装置
US8143689B2 (en) 2005-09-20 2012-03-27 Bae Systems Plc Sensor device
JP2014001969A (ja) * 2012-06-15 2014-01-09 Hitachi Automotive Systems Ltd 熱式流量計
JP2014001983A (ja) * 2012-06-15 2014-01-09 Hitachi Automotive Systems Ltd 熱式流量計
JP2020016465A (ja) * 2018-07-23 2020-01-30 ミネベアミツミ株式会社 流体センサ

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6239722A (ja) * 1985-08-16 1987-02-20 Nippon Soken Inc 流量センサ用膜式抵抗
JPS63208717A (ja) * 1987-02-25 1988-08-30 Fuji Electric Co Ltd 質量流量計
JPS643517A (en) * 1987-06-26 1989-01-09 Shimadzu Corp Flow rate sensor and its production
JPH11281445A (ja) * 1998-03-31 1999-10-15 Mitsubishi Electric Corp 流量検出素子及び流量センサ

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6239722A (ja) * 1985-08-16 1987-02-20 Nippon Soken Inc 流量センサ用膜式抵抗
JPS63208717A (ja) * 1987-02-25 1988-08-30 Fuji Electric Co Ltd 質量流量計
JPS643517A (en) * 1987-06-26 1989-01-09 Shimadzu Corp Flow rate sensor and its production
JPH11281445A (ja) * 1998-03-31 1999-10-15 Mitsubishi Electric Corp 流量検出素子及び流量センサ

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8143689B2 (en) 2005-09-20 2012-03-27 Bae Systems Plc Sensor device
JP2007212199A (ja) * 2006-02-07 2007-08-23 Yamatake Corp センサのパッケージ構造及びこれを有するフローセンサ
JP2010230312A (ja) * 2009-03-25 2010-10-14 Fujikura Ltd 半導体センサの製造方法及び半導体センサ
JP2011048165A (ja) * 2009-08-27 2011-03-10 Hitachi Consumer Electronics Co Ltd 投写型表示装置
JP2014001969A (ja) * 2012-06-15 2014-01-09 Hitachi Automotive Systems Ltd 熱式流量計
JP2014001983A (ja) * 2012-06-15 2014-01-09 Hitachi Automotive Systems Ltd 熱式流量計
JP2020016465A (ja) * 2018-07-23 2020-01-30 ミネベアミツミ株式会社 流体センサ

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