阅读说明：本技术 电磁波传感器 (Electromagnetic wave sensor ) 是由 太田尚城 原晋治 青木进 小村英嗣 海津明政 于 2018-03-07 设计创作，主要内容包括：本发明提供一种电磁波传感器,其能够抑制来自局部热源的热对辐射热计膜造成的影响。电磁波传感器(1)具有：第一基板(2)；与第一基板(2)相对设置的透射红外线的第二基板(3),在第二基板(3)与第一基板(2)之间形成内部空间(7)；设置在内部空间(7)中的、由第二基板(3)支承的多个辐射热计膜(8)；形成于第一基板(2)的局部热源(9)；将第一基板(2)与第二基板(3)连接的第一电连接部件(5)；和在第二基板(3)上或第二基板(3)内延伸的引线(10),其将第一电连接部件(5)与辐射热计膜(8)连接。(The invention provides an electromagnetic wave sensor which can inhibit the influence of heat from a local heat source on a bolometer film. An electromagnetic wave sensor (1) is provided with: a first substrate (2); a second substrate (3) that is arranged opposite to the first substrate (2) and transmits infrared rays, and an internal space (7) is formed between the second substrate (3) and the first substrate (2); a plurality of bolometer films (8) disposed in the inner space (7) and supported by the second substrate (3); a local heat source (9) formed on the first substrate (2); a first electrical connection member (5) that connects the first substrate (2) and the second substrate (3); and leads (10) extending on the second substrate (3) or within the second substrate (3) connecting the first electrical connection member (5) with the bolometer membrane (8).)

1. An electromagnetic wave sensor, comprising:

a first substrate;

a second substrate that is transparent to infrared rays and is disposed opposite to the first substrate, an internal space being formed between the second substrate and the first substrate;

a plurality of bolometer films disposed in the inner space and supported by the second substrate;

a local heat source formed on the first substrate;

a first electrical connection member connecting the first substrate and the second substrate; and

leads extending on or within the second substrate connecting the first electrical connection component with the bolometer film.

2. The electromagnetic wave sensor according to claim 1, characterized in that:

the bolometer includes a second electrical connection member extending from the second substrate toward the first substrate, and the bolometer film is supported by the second electrical connection member at a distance from the second substrate.

3. The electromagnetic wave sensor according to claim 2, characterized in that:

the second electrical connection component has a capacitor.

4. The electromagnetic wave sensor according to any one of claims 1 to 3, characterized in that:

has a plurality of selection transistors formed on the second substrate for selecting one bolometer film from the plurality of bolometer films.

5. The electromagnetic wave sensor according to claim 4, characterized in that:

the selection transistor is disposed so as to avoid a region of the second substrate that opposes the bolometer film.

6. The electromagnetic wave sensor according to claim 4 or 5, characterized in that:

and a filter film formed on an outer surface of the second substrate for attenuating light having an energy larger than an energy band gap of the selection transistor.

7. The electromagnetic wave sensor according to any one of claims 1 to 6, characterized in that:

the plurality of bolometer films are arranged in a row at an interval at least in a first direction, the first electrical connection part is located at one end side or the other end side of the row of the plurality of bolometer films, and a length of the lead wire connecting the first electrical connection part and the bolometer film closest to the first electrical connection part is longer than the interval.

8. The electromagnetic wave sensor according to claim 7, characterized in that:

the plurality of bolometer films are arranged in a plurality of columns at intervals in a second direction crossing the first direction, the plurality of bolometer films form an array constituted by a plurality of the rows and the plurality of columns, the first electrical connection parts of a part of the plurality of first electrical connection parts are alternately located at one end side and the other end side of the plurality of rows, and the first electrical connection parts of the remaining part of the plurality of first electrical connection parts are alternately located at one end side and the other end side of the plurality of columns.

9. The electromagnetic wave sensor according to claim 8, characterized in that:

at least one of the plurality of first electrical connection members located on the one end side of the row and the plurality of first electrical connection members located on the other end side of the row is shifted from each other in the first direction.

10. The electromagnetic wave sensor according to claim 8 or 9, characterized in that:

at least one of the plurality of first electrical connection members located on the one end side of the column and the plurality of first electrical connection members located on the other end side of the column is shifted from each other in the second direction.

11. The electromagnetic wave sensor according to any one of claims 1 to 10, characterized in that:

having a first radiation shield between the bolometer film and the first substrate for attenuating radiation from the first substrate.

12. The electromagnetic wave sensor according to claim 11, characterized in that:

there is a support member extending from the second substrate to the first substrate, the first radiation shield being supported by the support member.

13. The electromagnetic wave sensor according to claim 11 or 12, characterized in that:

the surface of the first radiation shielding member, which is opposite to the bolometer film, is a reflecting surface for reflecting infrared rays, and the interval between the reflecting surface and the bolometer film is 2-3.5 mu m.

14. The electromagnetic wave sensor according to any one of claims 1 to 13, characterized in that:

with a getter film located in said inner space.

15. The electromagnetic wave sensor according to any one of claims 1 to 14, characterized in that:

the display device includes a first antireflection film that forms at least a part of an outer surface of the second substrate.

16. The electromagnetic wave sensor according to any one of claims 1 to 15, characterized in that:

the second substrate has a second antireflection film that forms at least a part of an inner surface of the second substrate.

17. The electromagnetic wave sensor according to claim 16, characterized in that:

the second antireflection film is formed of a laminated film of a plurality of insulating films, and the lead is positioned inside the laminated film.

18. The electromagnetic wave sensor according to any one of claims 1 to 17, characterized in that:

a first convex region is formed in a region of the outer surface of the second substrate that faces the bolometer film.

19. The electromagnetic wave sensor according to claim 18, characterized in that:

a second convex region protruding outward from the first convex region is formed in a region of the outer surface of the second substrate that does not face the bolometer film.

20. The electromagnetic wave sensor according to any one of claims 1 to 19, characterized in that:

the bolometer film includes a non-sensing unit for performing temperature correction of an output from the bolometer film, and an electromagnetic wave shielding portion formed in a region of the second substrate opposite to the non-sensing unit.

21. The electromagnetic wave sensor according to claim 20, characterized in that:

a second radiation shield for suppressing radiation from the first substrate is disposed between the non-sensing unit and the first substrate.

22. The electromagnetic wave sensor according to any one of claims 1 to 21, characterized in that:

there is a thermal diffusion plate formed in a region of the first substrate opposite to the plurality of bolometer films and having a higher thermal conductivity than the first substrate.

Technical Field

The present invention relates to an electromagnetic wave sensor, and more particularly to an infrared sensor having a bolometer film.

Background

An infrared sensor having a bolometer film and detecting a temperature distribution of an object in an infrared wavelength range is known. In such an infrared sensor, the bolometer film changes in temperature due to infrared rays that enter the bolometer film from the outside and are absorbed by the bolometer film, and the change in temperature of the bolometer film is extracted as a change in resistance. There is a correlation between the temperature of an object and the emissivity (radiant energy) emitted from the object (Stefan-Boltzmann) law). Therefore, by detecting a temperature change of the bolometer film caused by radiant heat emitted from the object, the temperature distribution of the object can be measured.

As is clear from the above, in an infrared sensor having a bolometer film, it is necessary to exclude the influence of heat other than radiant heat as much as possible. Therefore, in general, in order to suppress the influence of convection, a bolometer film is provided in a vacuum casing having a window that transmits infrared rays. The infrared sensor having the bolometer film includes a component such as an ROIC (Read Out Integrated Circuit) that converts a change in resistance of the bolometer film into an electric signal. Such a member is a local heat source, and therefore, may have a large influence on the measurement result of the bolometer film. That is, in an infrared camera equipped with an infrared sensor, such a local heat source may be captured in an image.

Japanese patent No. 5923617 discloses a MEMS sensor in which an ROIC is formed on a first wafer, and a microbolometer is supported on a second wafer. The microbolometer is supported by the second wafer via a bent lead, and a surface of the second wafer facing the microbolometer is a concave portion. Thereby, the microbolometer is configured to float in the space between the first wafer and the second wafer. The ROIC and the microbolometer are electrically connected by solder material extending between the first and second wafers in a direction orthogonal to the wafers.

Disclosure of Invention

In the MEMS sensor disclosed in japanese patent No. 5923617, the ROIC as a local heat source and the microbolometer are provided on different wafers (substrates), and therefore, the influence of heat generated by the ROIC can be suppressed. However, since heat from the ROIC is transferred to the second wafer via the solder material and further transferred to the microbolometer through the lead, the influence of heat from the ROIC cannot be sufficiently suppressed.

The invention aims to provide an electromagnetic wave sensor which can inhibit the influence of heat from a local heat source on a bolometer film.

The present invention provides an electromagnetic wave sensor, comprising: a first substrate; a second substrate disposed opposite to the first substrate and transmitting an electromagnetic wave, an inner space being formed between the second substrate and the first substrate; a plurality of bolometer films disposed in the inner space and supported by the second substrate; a local heat source formed on the first substrate; a first electrical connection member connecting the first substrate and the second substrate; and leads extending on or within the second substrate connecting the first electrical connection component with the bolometer membrane.

The leads extend on or within the second substrate. In other words, the leads are in physical contact with the second substrate along their paths. The heat transferred from the local heat source to the lead via the first electrical connection member is diffused to the second substrate through the physical contact portion along the path thereof. That is, the second substrate functions as a heat absorbing member that absorbs heat of the lead, and therefore, the influence of heat from the local heat source on the bolometer film can be suppressed.

The above and other objects, features and advantages of the present application will become apparent from the following detailed description, which refers to the accompanying drawings that illustrate the present application.

Drawings

Fig. 1 is a schematic side view of an infrared sensor according to a first embodiment of the present invention.

Fig. 2 is a schematic plan view of the infrared sensor viewed from above in the Z direction of fig. 1.

Fig. 3 is a perspective view of the infrared sensor shown in fig. 1.

Fig. 4 is a schematic cross-sectional view of the second antireflection film.

Fig. 5 is a schematic side view of an infrared sensor according to a second embodiment of the present invention.

Fig. 6 is a schematic plan view of an infrared sensor according to a third embodiment of the present invention.

Fig. 7 is a schematic plan view of an infrared sensor according to a modification of the third embodiment.

Fig. 8 is a schematic side view of an infrared sensor according to a fourth embodiment of the present invention.

Fig. 9 is a schematic side view of an infrared sensor according to a fifth embodiment of the present invention.

Fig. 10 is a schematic side view of an infrared sensor according to a modification of the fifth embodiment.

Fig. 11A is a schematic cross-sectional view of an infrared sensor according to a sixth embodiment of the present invention.

Fig. 11B is a schematic cross-sectional view of an infrared sensor of a comparative example.

Fig. 12 is a schematic cross-sectional view of an infrared sensor according to a seventh embodiment of the present invention.

Fig. 13 is a schematic flowchart showing an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14A is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14B is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14C is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14D is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14E is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14F is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14G is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14H is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14I is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Fig. 14J is a diagram showing a procedure of an example of the method for manufacturing an infrared sensor according to the present invention.

Description of the reference numerals

1 … … infrared ray sensor (electromagnetic wave sensor), 2 … … first substrate, 3 … … second substrate, 4 … … side wall, 5 … … first electric connection part, 5a … … first row electric connection part, 5b … … first column electric connection part, 6 … … second electric connection part, 6a … … second row electric connection part, 6b … … second column electric connection part, 7 … … internal space, 8 … … bolometer film, 9 … … local heat source, 10 … … lead wire, 10a … … row lead wire, 10b … … column lead wire, 11 … … selection transistor, 12 … … radiation shield, 13 … … support part, 14 … … first anti-reflection film, 15 … … second anti-reflection film, 16 … … thermal diffusion plate, 17 … … air suction film, 21 … … reflection film, 31 … … filter film, 41 … … first convex region, 43 … … second convex region, 51 … … non-sensing unit, 53 … … infrared shield, 61 … … capacitor, X … … first direction, Y … … second direction, Z … … third direction.

Detailed Description

Various embodiments of the electromagnetic wave sensor according to the present invention will be described below with reference to the drawings. In the following description and the drawings, the first direction X and the second direction Y are directions parallel to the main surfaces of the first substrate 2 and the second substrate 3, the first direction X corresponding to the rows of the array of the bolometer films 8, and the second direction Y corresponding to the columns of the array of the bolometer films 8. The third direction Z is a direction orthogonal to the first direction X and the second direction Y, and is a direction perpendicular to the main surfaces of the first substrate 2 and the second substrate 3.

In the following embodiments, an infrared sensor in which a plurality of bolometer films are arranged in a two-dimensional array is used as a target. Such an infrared sensor is mainly used as an imaging element of an infrared camera. The infrared camera can be used not only as a night vision device and a night vision mirror in a dark place, but also for measuring the temperature of a person or an object. In addition, an infrared sensor in which a plurality of bolometer films are arranged in a one-dimensional shape can be used as a sensor for measuring various temperatures or temperature distributions. Although the explanation is omitted, an infrared sensor in which a plurality of bolometer films are arranged in one dimension is also included in the scope of the present invention. The electromagnetic wave to be detected is not limited to infrared rays, and the electromagnetic wave sensor of the present invention may be a sensor for detecting a terahertz wave having a wavelength of 100 μm to 1mm, for example.

(first embodiment)

Fig. 1 is a schematic side view of an infrared sensor 1 according to a first embodiment of the present invention, and fig. 2 is a plan view of the infrared sensor 1 of fig. 1, showing only a bolometer film 8, a lead wire 10, and first and second electrical connection members 5 and 6, as viewed from above in the Z direction. Fig. 3 is an exploded perspective view of the infrared sensor 1 of fig. 1, showing the first substrate 2 and the second substrate 3 separately. The infrared sensor 1 includes a first substrate 2, a second substrate 3 provided to face the first substrate 2, and a side wall 4 connecting the first substrate 2 and the second substrate 3. The first substrate 2, the second substrate 3, and the side wall 4 form a sealed internal space 7, and the internal space 7 is made to be a negative pressure or vacuum. This can prevent or suppress convection of the gas in the internal space 7, and can reduce the thermal influence on the bolometer film 8. The internal space 7 may be at atmospheric pressure. In this case, the thermal influence on the bolometer film 8 increases, but the effect of the present invention can be achieved.

The first substrate 2 includes a silicon substrate 2a and an insulating film 2b, and various elements and wirings are formed on the surface of the silicon substrate 2a or inside the insulating film 2 b. The second substrate 3 has: a silicon substrate 3 a; and a first antireflection film 14 and a second antireflection film 15 covering both surfaces of the silicon substrate 3 a. The second substrate 3 functions as a window substrate that transmits long-wavelength infrared rays, and therefore, a germanium substrate or the like may be used instead of the silicon substrate 3a, but the silicon substrate 3a is more preferably used for the reason described later. The wavelength of the long-wavelength infrared ray is approximately 8 to 14 μm.

A plurality of bolometer films 8 of a substantially square shape are provided in the internal space 7. The plurality of bolometer films 8 form a two-dimensional lattice array composed of a plurality of rows R arranged at a constant interval Ax along the first direction X and a plurality of columns C arranged at a constant interval Ay along a direction intersecting the first direction X, preferably along the second direction Y orthogonal to the first direction X. Each bolometer film 8 constitutes a cell or pixel in the array. Examples of the number of rows and columns of the array include, but are not limited to, 640 rows × 480 columns, 1024 rows × 768 columns, and the like. The bolometer film 8 has: a silicon substrate; and a vanadium oxide (VOx) or amorphous silicon (a-Si) film formed on the silicon substrate. The bolometer film 8 also has a getter film 17 for maintaining the degree of vacuum of the internal space 7.

Elements such as an ROIC, a regulator, an a/D converter, and a multiplexer are formed inside the first substrate 2. The ROIC is an integrated circuit that converts the resistance change of the plurality of bolometer films 8 into an electrical signal. These elements are local heat sources 9 provided at predetermined positions on the first substrate 2. The first substrate 2 and the second substrate 3 are connected by a first electrical connection member 5. These elements are connected to the first electrical connection member 5 via the internal wiring 18 of the first substrate 2, a conduction path 19 connected to the internal wiring 18, and a terminal 20 connected to the conduction path 19.

The first electrical connection member 5 is a conductor having a columnar shape with a circular cross section, and can be produced by plating, for example. The dimension in the Z direction of the first electrical connection member 5 is larger (higher) than the dimension in the Z direction of the second electrical connection member 6 described later, and therefore, in view of manufacturability, the first electrical connection member 5 has a larger cross-sectional area than the second electrical connection member 6. The first electrical connection members 5 are composed of first row electrical connection members 5a and first column electrical connection members 5b, wherein the first row electrical connection members 5a are connected to later-described row leads 10a on the second substrate 3, and the first column electrical connection members 5b are connected to later-described column leads 10b on the second substrate 3. As shown in fig. 2, the plurality of first row electrical connection members 5a are collectively arranged on one end side of the row R of the bolometer films 8, and the plurality of first column electrical connection members 5b are collectively arranged on one end side of the column C of the bolometer films 8.

Each bolometer film 8 is supported on the second substrate 3 via a pair of second electrical connection members 6. The second electrical connection member 6 is also a conductor having a columnar shape with a circular cross section, and can be produced by plating, for example. The pair of second electrical connection members 6 is constituted by a second row electrical connection member 6a connected to the row lead 10a and a second column electrical connection member 6b connected to the column lead 10 b. The second row 6a and column 6b electrical connection members extend downward in the Z-direction from the row 10a and column 10b leads, respectively, toward the first substrate 2, terminating between the first 2 and second 3 substrates. Therefore, the bolometer film 8 is suspended within the internal space 7 with a space in the Z direction from the first substrate 2 and the second substrate 3. The bolometer films 8 are supported at 2 corners on diagonal lines thereof by the second row of electrical connection parts 6a and the second column of electrical connection parts 6 b. The second electrical connection member 6 supports the bolometer film 8, and supplies a detection current to the bolometer film 8.

A lead wire 10 that connects the first electrical connection member 5 and the bolometer film 8 and supplies a detection current to the bolometer film 8 is formed on the second substrate 3. The lead 10 is formed of a conductor such as copper. The lead wires 10 are formed in each row R and each column C of the bolometer film 8, and are formed in a lattice shape. That is, the lead 10 is composed of a row lead 10a extending in a row direction (first direction X) and a column lead 10b extending in a column direction (second direction Y). The row leads 10a connect the first row electrical connection members 5a with the second row electrical connection members 6a, and the column leads 10b connect the first column electrical connection members 5b with the second column electrical connection members 6 b. The row leads 10a sequentially connect the bolometer films 8 included in the corresponding rows R, and the column leads 10b sequentially connect the bolometer films 8 included in the corresponding columns C. In fig. 1, the row lead 10a is broken at a position opposite to the bolometer film 8 for convenience, but the row lead 10a is continuously extended as shown in fig. 2 and 3. The same applies to the column lead 10 b.

The lead wires 10 extend between the bolometer films 8 adjacent to each other. This can avoid interference between the lead wire 10 and the bolometer film 8, and can suppress an influence on the bolometer film 8 due to the lead wire 10 being heated by radiant heat of infrared rays. The row lead 10a and the column lead 10b extend at different positions in the Z direction with an insulating film 152 (see fig. 4) interposed therebetween so as to cross each other in a non-conductive manner. In the present embodiment, the row leads 10a extend above the column leads 10b, i.e., at positions closer to the second substrate 3 in the Z direction, but the row leads 10a may be positioned below the column leads 10 b. Further, since the silicon substrate 3a has some conductivity, the silicon substrate 3a and the row lead 10a are also insulated from each other by an insulating film 151 (see fig. 4). As described later, these insulating films 151 and 152 constitute a part of the second antireflection film 15.

The wiring length Bx of the row lead 10a between the first row electrical connection member 5a and the bolometer film 8 closest to the first row electrical connection member 5a is longer than the arrangement interval Ax in the first direction X of the bolometer films 8. Similarly, the wiring length By of the column lead 10b between the first column electrical connection member 5b and the bolometer film 8 closest to the first column electrical connection member 5b is longer than the arrangement interval Ay in the second direction Y of the bolometer films 8. Here, the wiring lengths Bx, By are not the straight-line distances between the bolometer film 8 and the first row electrical connection parts 5a or the first column electrical connection parts 5b, but the lengths along the paths of the row leads 10a or the column leads 10b, that is, the lengths of the center lines of the row leads 10a or the column leads 10 b. In the illustrated example, the lead 10 extends linearly in the first direction X and the second direction Y, but may extend in a meandering shape or a bent shape in order to secure the wiring lengths Bx and By.

A plurality of selection transistors 11 for selecting one bolometer film 8 from the plurality of bolometer films 8 are formed on the silicon substrate 3a of the second substrate 3. Each selection transistor 11 corresponds to each bolometer film 8. The selection transistor 11 is disposed so as to avoid a region (hereinafter referred to as a window region 3c) of the second substrate 3 facing the bolometer film 8. This can avoid diffuse reflection of infrared rays and a decrease in incidence efficiency. Further, the reason why the second substrate 3 has the silicon substrate 3a is not only that the silicon substrate 3a has infrared transmittance. Note that, by the second substrate 3 having the silicon substrate 3a, the selection transistor 11 can be formed on the second substrate 3.

At least a part of the outer surface of the second substrate 3 is preferably entirely formed of the first antireflection film 14. Here, the outer surface of the second substrate 3 refers to a surface of the second substrate 3 extending along the X-Y plane including the window region 3c, and does not include a side surface of the second substrate 3. The inner surface of the second substrate 3 is formed by a second antireflection film 15. Here, the inner surface of the second substrate 3 refers to a surface of the second substrate 3 which is in contact with the internal space 7. In other words, the outer surface and the inner surface of the silicon substrate 3a are covered with the first antireflection film 14 and the second antireflection film 15, respectively. The first antireflection film 14 can prevent or suppress reflection of incident light, and improve incidence efficiency of infrared rays. The second antireflection film 15 can prevent the infrared rays passing through the second substrate 3 from being reflected on the inner surface of the second substrate 3, and can allow the infrared rays to be smoothly incident on the bolometer film 8. The first antireflection film 14 and the second antireflection film 15 are laminated films in which layers having different refractive indices are alternately laminated, and the reflectance of light in a specific wavelength range is reduced by interference of waves reflected by the respective layers. The first antireflection film 14 and the second antireflection film 15 are a laminated film of a plurality of insulating films formed by laminating, for example, an oxide film, a nitride film, a sulfide film, a fluoride film, a boride film, a bromide film, a chloride film, a selenide film, a Ge film, a diamond film, a chalcogenide film, a Si film, or the like.

Fig. 4 is a schematic cross-sectional view of the second antireflection film 15. The row and column leads 10a and 10b are embedded in the second antireflection film 15. The second antireflection film 15 is composed of insulating layers 151 to 155, and the row leads 10a are embedded between the insulating layer 151 and the insulating layer 152, and the column leads 10b are embedded between the insulating layer 152 and the insulating layer 153. Each of the insulating layers 151 to 155 may be made of ZnS or SiO₂AlOx, SiN, AlN, MgF, CaF, Ge, YF, ZnSe, KBr, NaCl, BaF, diamond, chalcogenide, Si, etc. The insulating layers 154 and 155 are provided to improve the function of the second antireflection film 15, and may have a multilayer structure of 3 or more layers.

Either one or both of the first antireflection film 14 and the second antireflection film 15 may be omitted. Even in the case where the second antireflection film 15 is omitted, the row leads 10a and the column leads 10b need to be insulated by an insulating layer. Either one of the row lead 10a and the column lead 10b may also be exposed to the internal space 7. That is, one of the row lead 10a and the column lead 10b may extend inside the second substrate 3, and the other may extend on the surface of the second substrate 3.

A radiation shield 12 for attenuating or shielding radiation from the first substrate 2 is provided between each bolometer film 8 and the first substrate 2. The radiation shield 12 is supported by a plurality of (e.g., 4) support members 13 extending downward in the Z direction from the second substrate 3 to the first substrate 2. One end of the support member 13 is connected to the corner of the radiation shield 12, and the other end is connected to the second substrate 3. When the support member 13 is formed of a material having low thermal conductivity, the first substrate 2 may support the support member 13.

The radiation shield 12 is formed of a material having high reflectance to infrared rays, such as Au, Cu, Al, or the like. In order to maintain the structural strength, SiO may be formed on the opposite surface of the radiation shield 12 to the first substrate 2₂AlOx, SiN, AlN, MgF, CaF, Ge, etc. The face 12a of the radiation shield 12 opposite the bolometer film 8 reflects infrared rays. A portion of the infrared transmitting bolometer film 8. The radiation shield 12 reflects the infrared rays transmitted through the bolometer film 8 so as to be incident on the bolometer film 8 from the back side. This can improve the incidence efficiency of infrared rays to the bolometer film 8. The interval between the bolometer film 8 and the radiation shield 12 is around 1/4 times the wavelength λ of the incident infrared rays. Therefore, interference between the incident infrared ray and the reflected infrared ray can be avoided, and the infrared ray can be efficiently absorbed into the bolometer film 8. Since the wavelength λ of the infrared ray is approximately 8 to 14 μm, the distance between the bolometer film 8 and the radiation shield 12 is preferably about 2 to 3.5 μm, and more preferably about 2.5 to 3.0 μm in which the incidence efficiency of the infrared ray is the maximum.

A heat diffusion plate 16 is formed in a region of the first substrate 2 opposing the bolometer film 8. The thermal diffusion plate 16 is preferably a 1-piece continuous metal layer opposite all the bolometer films 8, and has a thermal conductivity higher than that of the first substrate 2. The heat diffusion plate 16 may be formed of a metal having high thermal conductivity, such as copper. The heat diffusion plate 16 is used to efficiently diffuse heat emitted from the local heat source 9 such as an ROIC located immediately below the heat diffusion plate, and to smooth the temperature distribution on the surface of the first substrate 2.

A getter film 17 is formed on a surface of the radiation shield 12 facing the first substrate 2. The getter film 17 is formed of Ti, TiW, Zn, ZnCo, or the like, and adsorbs residual gas in the internal space 7, thereby suppressing a decrease in the degree of vacuum of the internal space 7. The getter film 17 may be disposed anywhere in the internal space 7, and may be formed on the heat diffusion plate 16 of the first substrate 2, for example.

The infrared rays incident on the infrared sensor 1 from the window region 3c of the second substrate 3 are incident on the array of the bolometer films 8. The detection current flows in the first row electrical connection member 5a, the row lead 10a, the second row electrical connection member 6a, the selected bolometer film 8, the second column electrical connection member 6b, the column lead 10b, and the first column electrical connection member 5b in this order. The resistance change of the detection current is taken out as a change in voltage, and an electric signal (voltage signal) is supplied to the ROIC of the first substrate 2. The ROIC converts the voltage signal into a luminance temperature. The bolometer films 8 are sequentially selected in time series by the selection transistor 11, and the resistance change taken out from the selected bolometer films 8 is sequentially converted into a luminance temperature. This makes it possible to scan all the bolometer films 8 and obtain 1-screen image data.

In the infrared sensor 1 of the present embodiment, the influence of heat generated by the local heat source 9 such as ROIC on the bolometer film 8 is suppressed. First, the bolometer film 8 is supported not by the first substrate 2 provided with the local heat source 9 but by the second substrate 3. The heat transfer generated by the heat conduction from the local heat source 9 is substantially limited to the path through the first substrate 2, the first electrical connection part 5, the lead 10, the second electrical connection part 6 (there may also be heat conduction through the side wall 4, but the heat is negligible). Therefore, compared to the conventional structure in which the bolometer film 8 is supported by the first substrate 2, the heat transfer path length is long, and the heat from the local heat source 9 is difficult to transfer to the bolometer film 8.

In the present embodiment, the lead 10 is in physical contact with the second substrate 3 (more precisely, the second antireflection film 15) over the entire length thereof, and therefore the heat transferred through the lead 10 is diffused to the second substrate 3. The amount of heat diffused is positively correlated with the length of the lead 10, and the longer the lead 10, that is, the longer the lead 10 is in contact with the second substrate 3, the more heat is diffused toward the second substrate 3, and the more heat is difficult to be transferred to the bolometer film 8. The bolometer films 8 closest to the first electrical connection member 5 are most susceptible to the influence of heat even in the array of the bolometer films 8, but as described above, the wiring length bx (by) to the first electrical connection member 5 is longer than the arrangement interval ax (ay) of the bolometer films 8. Therefore, even the bolometer film 8 closest to the first electrical connection part 5 is less susceptible to heat conduction. In addition, the lead 10 need not be in physical contact with the second substrate 3 throughout its entire length, as long as it is in physical contact with the second substrate 3 at least in the section between the first electrical connection member 5 and the bolometer film 8 closest to the first electrical connection member 5 (i.e., most susceptible to thermal influence).

Further, the second substrate 3 is substantially uniformly heated by radiant heat of infrared rays (and visible light in a bright place). The influence of the radiant heat that heats the entire second substrate 3 is likely to be handled as background noise. In the infrared sensor 1, a phenomenon is problematic in which a part of the bolometer films 8 is locally heated to a high temperature relative to the other bolometer films 8 by the local heat source 9. However, as described above, in the infrared sensor 1 of the present embodiment, the influence of such local heating can be effectively reduced. In addition, the selection transistor 11 provided on the second substrate 3 is provided over a wide range and is sequentially driven, and therefore, a property as a local heat source is not exhibited, and only a detection current flows, and therefore, the amount of heat generation is small. Therefore, the thermal influence of the selection transistor 11 on the bolometer film 8 is of a substantially negligible level.

Further, in the present embodiment, a radiation shield 12 is provided between the bolometer film 8 and the first substrate 2. The radiation shield 12 thermally shields the radiation generated by the local heat source 9, so that the influence of the radiation heat on the bolometer film 8 is mitigated. In addition, since the temperature of the region of the first substrate 2 facing the array of bolometer films 8 is uniformized by the heat diffusion plate 16, the influence of the local heat source 9 can be further reduced.

In the present embodiment, the bolometer membrane 8 is suspended in the inner space 7 by the second electrical connection member 6. However, as described above, in the present embodiment, the length of the heat transfer path from the first substrate 2 to the bolometer film 8 is long, and therefore, the second electrical connection member 6 may be omitted. In this case, the bolometer film 8 is supported by the second substrate 3 in a state of being in direct contact with the second substrate 3.

(second embodiment)

Fig. 5 is a schematic side view of an infrared sensor 1 according to a second embodiment of the present invention. Here, differences from the first embodiment will be mainly described. The configuration and effects described above are omitted, and the same as those in the first embodiment. The infrared sensor 1 has a reflection film 21 formed on a surface 8a of the bolometer film 8 facing the first substrate 2. The infrared ray incident from the window region 3c of the second substrate 3 is absorbed by the bolometer film 8, but a part of the infrared ray transmits the bolometer film 8. The reflection film 21 reflects the transmitted infrared rays so as to be incident on the bolometer film 8 from the back side. This improves the incidence efficiency of infrared rays. The distance between the reflective film 21 and the second substrate 3 is preferably about 1/4, i.e., about 2 to 3.5 μm, of the wavelength λ of the incident infrared ray, and more preferably about 2.5 to 3.0 μm, where the incident efficiency of the infrared ray is the maximum. Therefore, interference between the incident infrared ray and the reflected infrared ray can be avoided, and the infrared ray can be efficiently absorbed into the bolometer film 8. As described later, the bolometer film 8 can be manufactured in the same wafer process as the second substrate 3, and therefore, the Z-direction interval between the bolometer film 8 and the second substrate 3 can be precisely controlled. Therefore, the distance between the reflection film 21 laminated on the bolometer film 8 and the second substrate 3 can be also precisely controlled.

(third embodiment)

Fig. 6 is a plan view similar to fig. 2 of an infrared sensor 1 according to a third embodiment of the present invention. Here, differences from the first embodiment will be mainly described. The configuration and effects described above are omitted, and the same as those in the first embodiment. The bolometer films 8 are formed in an array of rows R and columns C as in the first embodiment. In the present embodiment, some of the plurality of first-row electrical connection members 5a connected to the rows R of the plurality of row leads 10a are positioned on one end side of the rows R, and the other first-row electrical connection members 5a are positioned on the other end side of the rows R. The plurality of first row electrical connection members 5a are alternately located on one end side and the other end side of the plurality of rows R. Similarly, some of the first-column electrical connection members 5b connected to the column C of the plurality of column leads 10b are positioned on one end side of the column C, and the other first-column electrical connection members 5b are positioned on the other end side of the column C. The plurality of first-column electrical connection members 5b are alternately located on one end side and the other end side of the plurality of columns C. As described above, the sectional area of the first electrical connection part 5 is larger than that of the second electrical connection part 6. Therefore, depending on the size (interval) of the bolometer films 8, there is a possibility that the first electrical connection member 5 cannot secure a sufficient sectional area. When the interval of the bolometer films 8 is enlarged in order to secure a sufficient sectional area, there is a possibility that noise of the infrared sensor 1 increases. In the present embodiment, since the plurality of first electrical connection members 5a (5b) are arranged (alternately) on one end side and the other end side of the plurality of rows R (columns C) of the lead 10a (10b) every other one, one first electrical connection member 5a (5b) can be provided in the region of 2 rows R (columns C). Therefore, the installation area of the first electrical connection member 5 becomes substantially 2 times as large as the original area. Therefore, in the present embodiment, it is possible to suppress an increase in noise of the infrared sensor 1 while securing a sufficient cross-sectional area of the first electrical connection member 5.

Fig. 7 is a schematic plan view of an infrared sensor 1 according to a modification of the present embodiment. It is preferable that either one of the plurality of first row electrical connection members 5a located on one end side of the row R of the plurality of row leads 10a and the plurality of first row electrical connection members 5a located on the other end side of the row R is shifted from each other in the first direction X. Although not shown in the drawings, at least one of the plurality of first-column electrical connection members 5b located on one end side of the column C of the plurality of column leads 10b and the plurality of first-column electrical connection members 5b located on the other end side of the column C is preferably shifted from each other in the second direction Y. Since the restriction on the cross-sectional shape of the first electrical connection member 5 can be further reduced as compared with the arrangement pattern of the first electrical connection members 5 shown in fig. 6, it is easier to secure a sufficient cross-sectional area of the first electrical connection members 5.

(fourth embodiment)

Fig. 8 is a schematic side view of an infrared sensor 1 according to a fourth embodiment of the present invention. Here, differences from the first embodiment will be mainly described. The configuration and effects described above are omitted, and the same as those in the first embodiment. In the present embodiment, a filter film 31 for attenuating light having a wavelength having energy larger than the band gap of the selection transistor 11 or blocking the light is formed on the outer surface of the second substrate 3. When the second substrate 3 receives light having energy larger than the energy band gap of the selection transistor 11, the selection transistor 11 formed on the second substrate 3 may malfunction. The filter film 31 blocks or suppresses transmission of such light, and thus malfunction of the selection transistor 11 is less likely to occur. The filter film 31 may be formed on the side surface of the second substrate 3. The filter film 31 may be formed as a part of the second substrate 3. The filter film 31 may be formed of, for example, Ge, Si, chalcogenide, YF, ZnS, ZnSe, or the like. The filter film 31 may be formed as a part of the first antireflection film 14.

(fifth embodiment)

Fig. 9 is a schematic side view of the infrared sensor 1 according to the fifth embodiment of the present invention in the vicinity of the second substrate 3. Here, differences from the first embodiment will be mainly described. The configuration and effects described above are omitted, and the same as those in the first embodiment. The outer surface of the second substrate 3 has a microlens structure in which the first convex regions 41 are arranged in an array. Each first convex region 41 is formed at a position opposing the corresponding bolometer film 8. The first convex region 41 is a minute convex lens, and increases the effective opening diameter Deff of each bolometer film 8 (compared to fig. 1). In the case where the second substrate 3 is a flat plate, the window region 3c is determined by the size of a region where the wiring 10 (the row wiring 10a and the column wiring 10b) and the selection transistor 11 are not provided. In other words, the size of the light receiving portion of the bolometer film 8 is limited by the arrangement space of the lead wire 10 and the selection transistor 11. On the other hand, in the present embodiment in which the second substrate 3 has the microlens structure, infrared rays incident from the region facing the lead 10 and the selection transistor 11, that is, the region where the bolometer film 8 is not provided can be absorbed by the bolometer film 8, and the light receiving efficiency of infrared rays can be improved.

Fig. 10 is a schematic side view showing an infrared sensor 1 according to a modification of the present embodiment. In the present modification, the outer surface of the second substrate 3 has the second convex region 43 protruding outward from the first convex region 41 facing the bolometer film 8. That is, in the first direction X and the second direction Y, the outer surface of the second substrate 3 is repeatedly arranged in the order of the first convex region 41 facing the bolometer film 8, the flat region 42 having the same film thickness as the end portion of the first convex region 41, and the second convex region 43 having a film thickness larger than the film thickness of the top portion of the first convex region 41. As described later, the infrared sensor 1 can be manufactured by manufacturing the first substrate 2 and the second substrate 3 separately and bonding them to each other via the side wall 4 and the first electrical connection member 5. In the fabrication of the second substrate 3, the wafer process is performed with the wafer surface on which the selection transistors 11 and the leads 10 are formed as the upper side, but in the fabrication of the microlenses, the wafer surface on which the microlenses are to be fabricated needs to be the upper side. Therefore, first, microlenses are formed on a wafer, and then the wafer is turned upside down, and the wafer surface on which the microlenses are formed is adsorbed to a holder to form the lead 10 and the like. At this time, in the present embodiment, since only the second convex region 43 is in contact with the holder, the first convex region 41 can be prevented from coming into contact with the stent, and deterioration or damage of the first convex region 41 is less likely to occur.

(sixth embodiment)

Fig. 11A is a schematic side view of an infrared sensor 1 according to a sixth embodiment of the present invention. Here, differences from the first embodiment will be mainly described. The configuration and effects described above are omitted, and the same as those in the first embodiment. The infrared sensor 1 includes a non-sensing cell (blank cell)51 for performing temperature correction of the output of the bolometer film 8 as an active cell 52. The non-sensing element 51 has the same structure as the bolometer film 8 as the effective element 52, and is supported by the second substrate 3 in the same manner as the effective element 52. The non-sensor unit 51 receives the same radiation as the effective unit 52 from the peripheral structures, for example, the first substrate 2 and the second substrate 3, but does not receive the radiation of infrared rays from the outside. Therefore, the non-sensing unit 51 can be used as a correction unit for eliminating background noise caused by a factor other than infrared radiation from the outside. Therefore, the non-sensor unit 51 needs to be configured not to be irradiated with infrared rays from the outside. In the present embodiment, an infrared shielding portion 53 is formed in a region of the second substrate 3 facing the non-sensing unit 51. As shown in the comparative example of fig. 11B, the conventional non-inductive unit 161 is covered with a shield portion 164 formed on the first substrate 2. However, the manufacturing process of the shield portion 164 is complicated, which causes an increase in manufacturing cost. In the present embodiment, the infrared shielding part 53 can be easily formed in the manufacturing process of the second substrate 3, and therefore, the influence on the manufacturing cost can be suppressed.

A shield 54 for suppressing radiation from the first substrate 2 is provided between the non-sensing unit 51 and the first substrate 2. The shield 54 is integrally formed with the radiation shield 12, but may be separate from the radiation shield 12. By providing the shield 54, the influence of the radiation received from the first substrate 2 can be made the same between the effective cell 52 and the non-sensing cell 51, and the function of the non-sensing cell 51 as a correction cell can be improved.

(seventh embodiment)

Fig. 12 is a schematic side view of an infrared sensor 1 according to a seventh embodiment of the present invention. Here, differences from the first embodiment will be mainly described. The configuration and effects described above are omitted, and the same as those in the first embodiment. The second electrical connection member 6 has a capacitor 61. Specifically, the capacitor 61 is inserted into the second row electrical connection member 6a and the second column electrical connection member 6b, disconnecting the second row electrical connection member 6a and the second column electrical connection member 6b in the Z direction. The second electrical connection members 6a, 6b are formed of an electrically conductive material in order to supply a detection current. Therefore, the thermal conductivity is also higher than that of the insulating material, and it is possible to transfer the heat transferred in the leads 10a, 10b to the bolometer film 8. In the present embodiment, the capacitor 61 cuts off or suppresses heat conduction, and therefore, heat from the leads 10a, 10b is difficult to transfer to the bolometer film 8. In the present embodiment, since the detection current is supplied as an alternating current, the state of the bolometer film 8 is output as a change in the electric field. The capacitors 61 are provided in both the second row electrical connection member 6a and the second column electrical connection member 6b, but may be provided only in either one.

(method for manufacturing Infrared sensor 1)

Next, an example of a method for manufacturing the infrared sensor 1 of the present invention is shown with reference to fig. 13 and 14A to 14J. The infrared sensor 1 can be manufactured by a wafer process, and therefore, in the following description, the first substrate 2, the second substrate 3, and the silicon substrate 3a refer to wafers. Fig. 13 shows a schematic flow of a method for manufacturing the infrared sensor 1. The infrared sensor 1 of the present invention can be manufactured by the following steps 1, 2, and 3: step 1, forming an ROIC or the like on a first substrate 2; a step 2 of forming a bolometer film 8 and the like on the second substrate 3; and a step 3 of bonding the first substrate 2 and the second substrate 3. Step 3 is performed in a vacuum atmosphere. The manufacturing process of the first substrate 2 need not be described in detail, and therefore, the details thereof are omitted. Next, a process of forming the bolometer film 8 and the like on the second substrate 3 will be mainly described.

First, as shown in fig. 14A, the selection transistor 11 is formed on the silicon substrate 3 a. An insulating layer 91 is formed on the side of the selection transistor 11.

Next, as shown in fig. 14B, an insulating film 151 which is a part of the second antireflection film 15 is formed on the silicon substrate 3a in the region lateral to the selection transistor 11. Specifically, an opening is formed in a region of the insulating layer 91 to be the window region 3c by a photoresist (photoresist) step and a polishing step, and the insulating film 151 is formed in the opening by an arc deposition method.

Next, as shown in fig. 14C, row leads 10a are formed. Specifically, an opening of the resist is formed by a photoresist process and a polishing process, and the line lead 10a is formed in the opening by deposition, and the resist is removed.

Next, as shown in fig. 14D, an insulating film 152 which is a part of the second antireflection film 15 is formed above the selection transistor 11. Specifically, an opening of the resist is formed by a photoresist process and a polishing process, and the insulating film 152 is formed in the opening by deposition, thereby removing the resist.

Next, as shown in fig. 14E, a column wiring 10b is formed over the insulating film 152. Specifically, an opening of the resist is formed by a photoresist process and a polishing process, and the column lead 10b is formed in the opening by deposition, and the resist is removed.

Next, as shown in fig. 14F, the lower portion of the first electric wiring member 5 and the second electric wiring member 6 are formed. Specifically, the first sacrificial layer 92 is formed, an opening of the first sacrificial layer 92 is formed by a photoresist process and a polishing process, and the lower portion of the first electric wiring member 5 and the second electric wiring member 6 are formed by plating.

Next, as shown in fig. 14G, the bolometer films 8 are formed on the second electric wiring members 6 adjacent to each other. Specifically, the bolometer films 8 are formed on the second electric wiring members 6 adjacent to each other and the first sacrificial layer 92 therebetween, and the second electric wiring members 6 and the bolometer films 8 adjacent to each other are electrically connected.

Next, as shown in fig. 14H, a second sacrificial layer 93 is formed, an opening of the second sacrificial layer 93 is formed by a photoresist process and a polishing process, and an upper portion of the first electrical wiring member 5 is formed by plating.

Next, as shown in fig. 14I, the first sacrificial layer 92 and the second sacrificial layer 93 are removed by ashing.

Next, as shown in fig. 14J, the second substrate 3 is inverted in the vertical direction and bonded to the first substrate 2. The lower end portion of the first electric wiring member 5 is bonded to a pad 20 connected to the ROIC or the like. Although not shown, the first substrate 2 and the second substrate 3 are bonded to the side walls 4, respectively, to form an internal space 7 between the first substrate 2 and the second substrate 3.

While certain preferred embodiments of the present invention have been illustrated and described in detail above, it should be understood that various changes and modifications may be made without departing from the spirit and scope of the appended claims.