Infrared sensor and method for manufacturing the same

Abstract

The infrared sensor (100) comprises a first semiconductor substrate (1), a second semiconductor substrate (2), a sealing frame (3) and a first connecting portion (4). The first semiconductor substrate (1) comprises a first main surface (1a) and an infrared detection element (11). The second semiconductor substrate (2) comprises a second main surface (2a) and a signal processing circuit (21). The sealing frame (3) surrounds an internal space (IS) together with the first main surface (1a), the infrared detection element (11) and the second main surface (2a). The first connecting portion (4) electrically connects the infrared detection element (11) and the signal processing circuit (21). The internal space (IS) is sealed in a sealed state by the first main surface (1a), the infrared detection element (11), the second main surface (2a) and the sealing frame (3). The sealing frame (3) and the first connecting portion (4) are each sandwiched between the first main surface (1a) and the second main surface (2a).

Description

Technical Field

[0001] The present disclosure relates to an infrared sensor and a method for manufacturing the infrared sensor. Background Art

[0002] Infrared sensors are roughly divided into quantum type (cooling type) and thermal type (non-cooling type). The thermal type infrared sensor converts infrared absorbed by an infrared absorber into heat. The thermal type infrared sensor converts the temperature change caused by the converted heat into an electrical signal. The temperature change caused by infrared rays occurs in the infrared detection part of the thermal type infrared sensor. By the insulating structure in which the infrared detection part and the substrate of the thermal type infrared sensor are thermally isolated, the temperature change of the infrared detection part caused by the infrared detection part absorbing the incident infrared rays becomes larger. Furthermore, the infrared detection part can be maintained in the internal space of the insulating structure that becomes a vacuum. Thereby, the thermal resistance of the insulating structure is reduced by suppressing the heat conduction and convection of the gas caused by the gas in the internal space, so that the thermal insulation is further improved.

[0003] In addition, an infrared sensor is known in which an infrared sensor substrate and a signal processing circuit substrate are arranged in a manner facing each other. A heat-insulating structure is provided between the infrared sensor substrate and the signal processing circuit substrate. The internal space of the heat-insulating structure is configured to be heat-insulated by being sealed in a closed state. The infrared sensor substrate has a pixel array composed of a plurality of pixels including infrared detection elements. The signal processing circuit substrate has a signal processing circuit for processing output signals from each infrared detection element. The signal processing circuit is, for example, an analog / digital conversion circuit.

[0004] As an infrared sensor having the above structure, there is, for example, an optical device (infrared sensor) described in International Publication No. 2006 / 095834 (Patent Document 1). In the optical device described in the above publication, the photoelectric conversion part (infrared detection element) faces the gap (internal space) sealed in a sealed state. The gap is sealed in a sealed state by the first main surface of the substrate (first semiconductor substrate) on which the photoelectric conversion part is formed, the photoelectric conversion part, the second main surface of the signal circuit processing part (second semiconductor substrate), the sealing member, and the connecting wiring (first connecting part).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2006 / 095834 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the optical device described in the above-mentioned publication, after the substrate and the signal processing circuit unit are electrically connected by the connecting wiring, the substrate, the signal processing circuit unit and the connecting wiring are sealed by the sealing member to form a sealed state. The gap is formed by removing the sealing member. Therefore, in the optical device described in the above-mentioned publication, the sealing of the gap and the electrical connection between the substrate and the signal processing circuit unit are performed separately. Therefore, the manufacturing cost of the infrared sensor increases.

[0010] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide an infrared sensor and a method for manufacturing the infrared sensor that can suppress an increase in manufacturing cost.

[0011] Means for solving problems

[0012] The infrared sensor disclosed in the present invention comprises a first semiconductor substrate, a second semiconductor substrate, a sealing frame and a first connecting portion. The first semiconductor substrate includes a first main surface and an infrared detection element. The infrared detection element is arranged on the first main surface. The second semiconductor substrate includes a second main surface and a signal processing circuit. The second main surface faces the first main surface. The signal processing circuit is configured to process the signal of the infrared detection element. The sealing frame is connected to the first semiconductor substrate and the second semiconductor substrate. The sealing frame surrounds an internal space with the first main surface, the infrared detection element and the second main surface. The first connecting portion electrically connects the infrared detection element and the signal processing circuit. The internal space is sealed in a closed state by the first main surface, the infrared detection element, the second main surface and the sealing frame. The sealing frame and the first connecting portion are each sandwiched between the first main surface and the second main surface.

[0013] Effects of the Invention

[0014] According to the infrared sensor of the present disclosure, it is possible to suppress an increase in the manufacturing cost of the infrared sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a cross-sectional view schematically showing the structure of the infrared sensor according to the first embodiment.

[0016] Figure 2 This is a plan view schematically showing the structure of the infrared sensor according to the first embodiment.

[0017] Figure 3 This is a perspective view schematically showing the structure of the infrared sensor according to the first embodiment.

[0018] Figure 4 This is a cross-sectional view schematically showing the structure of an infrared sensor according to a modified example of the first embodiment.

[0019] Figure 5 This is a plan view schematically showing the structure of an infrared sensor according to a modified example of the first embodiment.

[0020] Figure 6 This is a perspective view schematically showing the structure of an infrared sensor according to a modified example of the first embodiment.

[0021] Figure 7 This is a perspective view schematically showing another method of manufacturing the infrared sensor according to the first embodiment.

[0022] Figure 8 This is a circuit diagram schematically showing the structure of the infrared sensor according to the first embodiment.

[0023] Fig. 9 This is a circuit diagram schematically showing the structure of the first semiconductor substrate according to the first embodiment.

[0024] Fig.10 This is a circuit diagram schematically showing the configuration of a voltage regulating circuit of a first semiconductor substrate according to the first embodiment.

[0025] Fig.11 This is a cross-sectional view schematically showing the structure of the infrared sensor according to the second embodiment.

[0026] Fig.12 This is a cross-sectional view schematically showing the structure of an infrared sensor according to Embodiment 3.

[0027] Fig.13 This is a cross-sectional view schematically showing the structure of an infrared sensor according to a fourth embodiment.

[0028] Fig.14 This is a cross-sectional view schematically showing the structure of an infrared sensor according to the fifth embodiment.

[0029] Fig.15 This is a cross-sectional view schematically showing the structure of an infrared sensor according to the sixth embodiment.

[0030] Fig.16 This is a cross-sectional view schematically showing the structure of an infrared sensor according to the sixth embodiment.

[0031] (Description of the accompanying symbols)

[0032] 1: 1st semiconductor substrate; 1a: 1st main surface; 2: 2nd semiconductor substrate; 2a: 2nd main surface; 3: sealing frame; 4: 1st connecting part; 5: 2nd connecting part; 6: anti-reflection film; 11: infrared detection element; 13: 1st substrate part; 21: signal processing circuit; 22: 2nd substrate part; 100: infrared sensor; G: recess; IR: infrared; IS: internal space; IT1: 1st infrared transmission part; IT2: 2nd infrared transmission part; P: 2nd main surface part. DETAILED DESCRIPTION

[0033] Hereinafter, the embodiment will be described based on the drawings. In addition, in the following, the same reference numerals are given to the same or corresponding parts, and the repeated description will not be repeated.

[0034] Implementation method 1.

[0035] use Figure 1 and Figure 2 , the structure of the infrared sensor 100 according to the first embodiment will be described. Figure 1 is along Figure 2 Cross-sectional view of line II.

[0036] The infrared sensor 100 is an infrared sensor for detecting infrared rays IR incident on the infrared sensor 100. The infrared sensor 100 of the present embodiment is a thermal infrared sensor.

[0037] like Figure 1 As shown, the infrared sensor 100 includes a first semiconductor substrate 1, a second semiconductor substrate 2, a sealing frame 3, and a first connection portion 4. The first semiconductor substrate 1 and the second semiconductor substrate 2 are overlapped with a gap therebetween. The sealing frame 3 and the first connection portion 4 are sandwiched between the first semiconductor substrate 1 and the second semiconductor substrate 2, respectively.

[0038] In the present embodiment, the Z-axis direction is a direction along the direction in which the first semiconductor substrate 1 and the second semiconductor substrate 2 overlap. The positive Z-axis direction is a direction along the Z-axis direction and from the first semiconductor substrate 1 toward the second semiconductor substrate 2. The negative Z-axis direction is a direction along the Z-axis direction and from the second semiconductor substrate 2 toward the first semiconductor substrate 1. The X-axis direction is a direction perpendicular to the Z-axis direction and extending along the first semiconductor substrate 1. The Y-axis direction is a direction perpendicular to the X-axis direction and the Z-axis direction, respectively. The in-plane direction of the first semiconductor substrate 1 is a direction along the X-axis direction and the Y-axis direction.

[0039] In the present embodiment, the infrared ray IR is incident on the infrared sensor 100 along the negative direction of the Z axis. The infrared sensor 100 is configured to detect the infrared ray IR incident on the infrared sensor 100 along the negative direction of the Z axis. In addition, in the present embodiment, the infrared ray IR is incident on the infrared sensor 100 along a certain direction, which means that the infrared ray IR having a main component along the direction is incident on the infrared sensor 100. Therefore, the infrared ray IR may also have a component along a direction different from the direction.

[0040] The first semiconductor substrate 1 includes a first main surface 1a, a first rear surface 1b, an infrared detection element 11, and a control circuit 12. The first semiconductor substrate 1 may include a plurality of infrared detection elements 11. In the present embodiment, the first semiconductor substrate 1 includes a plurality of infrared detection elements 11.

[0041] The first main surface 1a extends outward from the sealing frame 3 along the in-plane direction (X-axis direction and Y-axis direction) of the first semiconductor substrate 1. The first main surface 1a has a flat surface. The first back surface 1b faces the first main surface 1a. Therefore, the first back surface 1b extends along the in-plane direction (X-axis direction and Y-axis direction) of the first main surface 1a on the opposite side to the second semiconductor substrate 2 with respect to the first main surface 1a.

[0042] The infrared detection element 11 is arranged on the first main surface 1a. The infrared detection element 11 is configured to generate a detection signal when infrared IR is incident on the infrared detection element 11. Thus, the first semiconductor substrate 1 is configured as an infrared sensor substrate. The infrared detection element 11 is, for example, a diode, a resistance bolometer, a thin film ferroelectric, a pyroelectric element, or an element using MEMS (MicroElectro Mechanical Systems) technology.

[0043] In the present embodiment, the infrared ray IR is incident on the infrared detection element 11 through the second semiconductor substrate 2 along the negative direction of the Z axis. Therefore, the infrared detection element 11 is configured to face the second semiconductor substrate 2. The infrared sensor 100 is configured to detect the infrared ray IR incident on the infrared detection element 11 through the second semiconductor substrate 2. In addition, as described later, the infrared sensor 100 may also be configured to detect the infrared ray IR incident on the infrared detection element 11 through the first back surface 1b of the first semiconductor substrate 1.

[0044] In this embodiment, two infrared detection elements 11 are used as one unit to form a pixel PX. A plurality of pixels PX form a pixel array PXA. The control circuit 12 is configured to control the plurality of infrared detection elements 11. The control circuit 12 is configured to control the plurality of pixels PX. In addition, the detailed structure and operation of the pixel PX and the control circuit 12 will be described later.

[0045] The first semiconductor substrate 1 may further include support pins (not shown). The support pins are arranged on the first main surface 1a. The infrared detection element 11 can be hollowly held above the first main surface 1a by the support pins. In other words, the infrared detection element 11 can be arranged away from the first main surface 1a by the support pins.

[0046] The second semiconductor substrate 2 extends along the in-plane direction (X-axis direction and Y-axis direction) of the first main surface 1a. The second semiconductor substrate 2 is arranged away from the first semiconductor substrate 1. The second semiconductor substrate 2 faces the first semiconductor substrate 1. The second semiconductor substrate 2 faces the first semiconductor substrate 1 in parallel. The distance between the first semiconductor substrate 1 and the second semiconductor substrate 2 along the Z-axis direction is the same as the size of the sealing frame 3 and the first connecting portion 4 along the Z-axis direction.

[0047] The second semiconductor substrate 2 includes a second main surface 2a, a second back surface 2b, and a signal processing circuit 21. The second main surface 2a faces the first main surface 1a. The second main surface 2a is separated from the first main surface 1a and faces the first main surface 1a. The second main surface 2a extends outward from the sealing frame 3 along the in-plane direction (X-axis direction and Y-axis direction) of the first main surface 1a. The second back surface 2b faces the second main surface 2a. Therefore, the second back surface 2b extends along the in-plane direction (X-axis direction and Y-axis direction) of the second main surface 2a on the opposite side of the first semiconductor substrate 1 relative to the second main surface 2a.

[0048] The signal processing circuit 21 is configured to process the signal of the infrared detection element 11. Specifically, the signal processing circuit 21 is configured to process the detection signal sent from the infrared detection element 11. In the present embodiment, the signal processing circuit 21 is configured to process the detection signal sent from each of the plurality of infrared detection elements 11. Thus, the second semiconductor substrate 2 is configured as a signal processing circuit substrate.

[0049] The signal processing circuit 21 includes, for example, a readout circuit, an amplifier, a sample-and-hold device, an analog / digital converter, and a digital signal processing circuit. The readout circuit is configured to read out output signals sent from each of the plurality of infrared detection elements 11. The amplifier is configured to amplify the signals sent from each of the plurality of infrared detection elements 11. The detailed structure and operation of the signal processing circuit 21 will be described later.

[0050] In the present embodiment, the second semiconductor substrate 2 includes a second substrate portion 22 and a second infrared-transmitting portion IT2. The second substrate portion 22 and the second infrared-transmitting portion IT2 are configured to transmit infrared rays IR. The second infrared-transmitting portion IT2 is configured to transmit infrared rays IR more than the second substrate portion 22. The second infrared-transmitting portion IT2 faces the infrared detection element 11.

[0051] The second infrared-transmitting portion IT2 is added with impurities such as phosphorus (P) or boron (B). As a result, the second infrared-transmitting portion IT2 has a resistivity of, for example, 1Ω·cm or more. The absorption of infrared rays IR by the second infrared-transmitting portion IT2 is correlated with the resistivity of the second infrared-transmitting portion IT2. Therefore, the greater the resistivity of the second infrared-transmitting portion IT2, the less the second infrared-transmitting portion IT2 absorbs infrared rays IR. Therefore, when the resistivity of the second infrared-transmitting portion IT2 is, for example, 1Ω·cm or more, the infrared IR wavelength is suppressed from being absorbed by the second semiconductor substrate 2.

[0052] like Figure 1 and Figure 2As shown in FIG. 1 , the sealing frame 3 is connected to the first semiconductor substrate 1 and the second semiconductor substrate 2. The sealing frame 3, the first main surface 1a, the infrared detection element 11, and the second main surface 2a surround the internal space IS. The internal space IS is sealed in a sealed state by the first main surface 1a, the infrared detection element 11, the second main surface 2a, and the sealing frame 3. Figure 1 As shown in FIG. 1 , the internal space IS is sandwiched between the first main surface 1a and the infrared detection element 11 and the second main surface 2a along the Z-axis direction. The infrared detection element 11 and the second infrared transmission part IT2 each face the internal space IS. The first connection part 4, the control circuit 12 and the signal processing circuit 21 are arranged in the area outside the internal space IS. Figure 2 As shown, the inner space IS is surrounded by a sealing frame 3 around the Z axis.

[0053] Gas cannot travel back and forth between the internal space IS and the area outside the internal space IS. Therefore, the internal space IS is thermally insulated. In the present embodiment, the internal space IS is sealed in a vacuum state. In the present embodiment, the internal space IS may not be sealed in a complete vacuum state.

[0054] like Figure 1 As shown, the sealing frame 3 is sandwiched between the first semiconductor substrate 1 and the second semiconductor substrate 2 along the direction in which the first semiconductor substrate 1 and the second semiconductor substrate 2 overlap (Z-axis direction). The first end of the sealing frame 3 in the Z-axis direction is in contact with the first main surface 1a. The second end of the sealing frame 3 in the Z-axis direction is in contact with the second main surface 2a. The sealing frame 3 supports the first semiconductor substrate 1 and the second semiconductor substrate 2 along the Z-axis direction. Therefore, the sealing frame 3 mechanically connects the first semiconductor substrate 1 and the second semiconductor substrate 2. In addition, the sealing frame 3 does not electrically connect the first semiconductor substrate 1 and the second semiconductor substrate 2.

[0055] The material of the sealing frame 3 is conductive. The material of the sealing frame 3 is, for example, metal. The shape of the sealing frame 3 is annular. The sealing frame 3 has, for example, a hollow prism shape. The shape and size of the sealing frame 3 may be appropriately determined as long as they surround the infrared detection element 11. The sealing frame 3 may further surround the control circuit 12, for example.

[0056] The first connection portion 4 electrically connects the first semiconductor substrate 1 and the second semiconductor substrate 2. Specifically, the first connection portion 4 electrically connects the infrared detection element 11 and the signal processing circuit 21. The material of the first connection portion 4 has conductivity. The first connection portion 4 is configured as a bump, for example.

[0057] The first connection portion 4 is sandwiched between the first semiconductor substrate 1 and the second semiconductor substrate 2 along the direction in which the first semiconductor substrate 1 and the second semiconductor substrate 2 overlap (Z-axis direction). The first end of the first connection portion 4 in the Z-axis direction is in contact with the first main surface 1a. The second end of the first connection portion 4 in the Z-axis direction is in contact with the second main surface 2a. Therefore, the first connection portion 4 supports the first semiconductor substrate 1 and the second semiconductor substrate 2 along the Z-axis direction. The first connection portion 4 mechanically connects the first semiconductor substrate 1 and the second semiconductor substrate 2.

[0058] The sealing frame 3 and the first connecting portion 4 are each sandwiched between the first main surface 1a and the second main surface 2a. The sealing frame 3 and the first connecting portion 4 have the same size along the direction in which the first semiconductor substrate 1 and the second semiconductor substrate 2 overlap (Z-axis direction).

[0059] In the present embodiment, the material of the first connecting portion 4 is the same as the material of the sealing frame 3. Therefore, the melting point of the first connecting portion 4 is the same as the melting point of the sealing frame 3.

[0060] The infrared sensor 100 further includes a second connecting portion 5. The second connecting portion 5 is sandwiched between the first main surface 1a and the second main surface 2a. The first end of the second connecting portion 5 in the Z-axis direction is in contact with the first main surface 1a. The second end of the second connecting portion 5 in the Z-axis direction is in contact with the second main surface 2a. Therefore, the second connecting portion 5 supports the first semiconductor substrate 1 and the second semiconductor substrate 2 along the Z-axis direction. The second connecting portion 5 mechanically connects the first semiconductor substrate 1 and the second semiconductor substrate 2. In addition, the second connecting portion 5 does not electrically connect the first semiconductor substrate 1 and the second semiconductor substrate 2. The second connecting portion 5 is configured as a dummy bump.

[0061] In this embodiment, the second connection part 5 has a higher melting point than the first connection part 4 and the sealing frame 3. For example, when the first connection part 4 and the sealing frame 3 are made of indium (In) or an indium alloy, the second connection part 5 is made of nickel (Ni) or copper (Cu).

[0062] The infrared sensor 100 further includes an anti-reflection film 6. In the present embodiment, the anti-reflection film 6 is arranged on the side opposite to the first semiconductor substrate 1 with respect to the second main surface 2a. The anti-reflection film 6 covers the second back surface 2b. The anti-reflection film 6 overlaps with the infrared detection element 11 along the Z-axis direction. Therefore, the infrared IR passes through the anti-reflection film 6 and enters the infrared detection element 11.

[0063] The antireflection film 6 is configured to prevent reflection of infrared rays IR. In the present embodiment, the antireflection film 6 does not necessarily have to completely prevent reflection of infrared rays IR. The antireflection film 6 may be configured to suppress reflection of infrared rays IR incident on the antireflection film 6.

[0064] The anti-reflection film 6 is, for example, an anti-reflection coating (AR coating, AR: Anti Reflection) such as diamond-like carbon (DLC: Diamond Like Carbon) or zinc sulfide (ZnS: Zinc Sulfide).

[0065] like Figure 2 As shown, the first connection portion 4 includes a plurality of first connection portions 41. Each of the plurality of first connection portions 41 electrically connects the first semiconductor substrate 1 and the second semiconductor substrate 2. Each of the plurality of first connection portions 41 has, for example, a cylindrical shape. Each of the plurality of first connection portions 41 may have the same outer diameter.

[0066] The second connection portion 5 includes a plurality of second connection portions 51. Each of the plurality of second connection portions 51 does not electrically connect the first semiconductor substrate 1 and the second semiconductor substrate 2. Each of the plurality of second connection portions 51 has, for example, a cylindrical shape. Each of the plurality of second connection portions 51 may have the same outer diameter.

[0067] The second infrared-transmitting portion IT2 overlaps the infrared detection element 11 along the direction (Z-axis direction) in which the first semiconductor substrate 1 and the second semiconductor substrate 2 overlap. The control circuit 12 and the signal processing circuit 21 do not overlap the infrared detection element 11 along the direction (Z-axis direction) in which the first semiconductor substrate 1 and the second semiconductor substrate 2 overlap. The signal processing circuit 21 is located between the first connecting portion 4 and the second connecting portion 5 along the Y-axis direction.

[0068] like Figure 2 and Figure 3 As shown in FIG. 1 , the size of the first semiconductor substrate 1 in the in-plane direction (X-axis direction and Y-axis direction) may be larger than the size of the second semiconductor substrate 2 in the in-plane direction (X-axis direction and Y-axis direction). In this embodiment, the control circuit 12 is arranged to overlap with the second semiconductor substrate 2 along the Z-axis direction. The control circuit 12 may also be arranged not to overlap with the second semiconductor substrate 2 along the Z-axis direction. Figure 3 In FIG. 1 , for the convenience of explanation, the infrared sensor 100 is shown in an appropriately simplified manner.

[0069] Next, use Figures 4 to 6 , a structure of infrared sensor 100 according to a modified example of embodiment 1 is described. Figure 4 is along Figure 5 Cross-sectional view along line IV-IV.

[0070] like Figure 4 As shown, the control circuit 12 of the modification of Embodiment 1 faces the second main surface 2a. Specifically, the control circuit 12 faces the signal processing circuit 21. The control circuit 12 overlaps the signal processing circuit 21 in the Z-axis direction.

[0071] like Figure 5 As shown, the control circuit 12 includes a first control circuit portion 12a and a second control circuit portion 12b. The first control circuit portion 12a and the second control circuit portion 12b are electrically connected via wiring (not shown). The first control circuit portion 12a and the signal processing circuit 21 are located between the first connection portion 4 and the second connection portion 5 along the Y-axis direction. Figure 5 and Figure 4 As shown, the first control circuit unit 12 a faces the signal processing circuit 21 .

[0072] like Figure 5 and Figure 6 As shown, the dimensions of the first semiconductor substrate 1 along the X-axis direction and the Y-axis direction can be the same as the dimensions of the second semiconductor substrate 2 along the X-axis direction and the Y-axis direction. Figure 6 In FIG. 1 , for the convenience of explanation, the infrared sensor 100 is shown in an appropriately simplified manner.

[0073] Next, use Figure 1 and Figure 7 , a method for manufacturing the infrared sensor 100 according to the first embodiment is described.

[0074] The method for manufacturing the infrared sensor 100 includes a preparation step S101 and an electrical connection step S102 .

[0075] like Figure 1 As shown in FIG. 1 , a first semiconductor substrate 1, a second semiconductor substrate 2, a sealing frame 3, and a first connecting portion 4 are prepared. In this embodiment, a second connecting portion 5 is also prepared.

[0076] Specifically, the first semiconductor substrate 1 and the second semiconductor substrate 2 are prepared in accordance with the following process. First, a silicon (Si) substrate serving as the first semiconductor substrate 1 is used in a wafer process to form a pixel array PXA (see FIG. 1 ). Figure 1 ) and control circuit 12.

[0077] Next, metallization patterns are formed in the region where the sealing frame 3 is arranged on the silicon substrate serving as the first semiconductor substrate 1 and the region where the sealing frame 3 is arranged on the silicon substrate serving as the second semiconductor substrate 2. The region where the sealing frame 3 is arranged is located outside the pixel array.

[0078] Specifically, for example, titanium (Ti) or chromium (Cr) and copper (Cu) are formed in sequence on the entire surface of the first main surface 1a of the first semiconductor substrate 1 by sputtering. Then, a resist pattern is formed by photolithography (photolithography). Next, nickel (Ni) and gold (Au) are formed in sequence on the first main surface 1a by electrolytic plating. Then, the resist pattern is removed. The base film is removed. Thus, a metallization pattern is formed on the first semiconductor substrate 1.

[0079] The second semiconductor substrate 2 is provided with a metallization pattern similar to the first semiconductor substrate 1. The second semiconductor substrate 2 may be manufactured independently of the first semiconductor substrate 1. Thus, the second semiconductor substrate 2 may be manufactured by a conventional general silicon wafer process.

[0080] Next, silicon etching or the like is performed on each of the silicon substrates to be the first semiconductor substrate 1 and the second semiconductor substrate 2 by micromachining technology. Thus, the first semiconductor substrate 1 and the second semiconductor substrate 2 are manufactured.

[0081] Next, the sealing frame 3 and the first connecting portion 4 are sandwiched between the first main surface 1a, the infrared detection element 11, and the second main surface 2a, respectively, so that the internal space IS is surrounded by the first main surface 1a, the infrared detection element 11, the second main surface 2a, and the sealing frame 3, and the internal space IS is sealed in a sealed state. In addition, the second connecting portion 5 is sandwiched between the first main surface 1a and the second main surface 2a together with the sealing frame 3 and the first connecting portion 4.

[0082] Specifically, the first end of the sealing frame 3 is bonded to the first main surface 1a. The first end of the first connecting portion 4 is bonded to the first main surface 1a. The second end of the sealing frame 3 is bonded to the second main surface 2a. The second end of the first connecting portion 4 is bonded to the second main surface 2a. Thus, the internal space IS is sealed. The first semiconductor substrate 1 and the second semiconductor substrate 2 are connected to each other via the sealing frame 3, the first connecting portion 4, and the second connecting portion 5. The first semiconductor substrate 1 and the second semiconductor substrate 2 are configured to be separated by the dimension of the sealing frame 3, the first connecting portion 4, and the second connecting portion 5 along the Z-axis direction.

[0083] In the present embodiment, the internal space IS is sealed in a vacuum atmosphere by the first main surface 1a, the infrared detection element 11, the second main surface 2a, and the sealing frame 3. Specifically, in the vacuum atmosphere, the first main surface 1a and the second main surface 2a are bonded to the sealing frame 3 while the temperatures of the first semiconductor substrate 1 and the second semiconductor substrate 2 are maintained at a temperature higher than the melting point of the material of the sealing frame 3.

[0084] The sealing frame 3 and the first connecting portion 4 are respectively sandwiched between the first main surface 1a, the infrared detection element 11, and the second main surface 2a, and the infrared detection element 11 and the signal processing circuit 21 are electrically connected by the first connecting portion 4. Specifically, the first end of the first connecting portion 4 is electrically connected to the infrared detection element 11 or the wiring (not shown) connected to the infrared detection element 11. The second end of the first connecting portion 4 is electrically connected to the signal processing circuit 21 or the wiring (not shown) connected to the signal processing circuit 21.

[0085] like Figure 7As shown, during the manufacturing process, a first semiconductor substrate 1 (see Figure 1 ) and the first wafer 10 and the second semiconductor substrate 2 (refer to Figure 1 ) of the second wafer 20. The first semiconductor substrate 1 can be manufactured by processing in a wafer form (see Figure 1 ) and the second semiconductor substrate 2 (refer to Figure 1 ).exist Figure 7 In the figure, only one sealing frame 3, first connecting portion 4, and second connecting portion 5 are shown, but a plurality of sealing frames 3, first connecting portion 4, and second connecting portion 5 are prepared.

[0086] According to the above, the sealing of the internal space IS and the electrical connection of the infrared detection element 11 and the signal processing circuit 21 are performed together.

[0087] Next, use Figure 1 , the operating principle and sensitivity of the infrared sensor 100 according to the first embodiment are described.

[0088] The infrared sensor 100 is configured to convert infrared IR absorbed by the infrared sensor 100 into heat. Specifically, the infrared detection element 11 is configured to convert infrared IR absorbed by the infrared detection element 11 into heat. The infrared sensor 100 is configured to convert the temperature change caused by the converted heat into an electrical signal. Therefore, the infrared sensor 100 is configured to detect infrared IR based on the temperature change of the infrared detection element 11.

[0089] Thus, the sensitivity of the infrared sensor 100 is improved by suppressing the temperature change of the infrared detection element 11 due to the temperature change of the internal space IS.

[0090] Specifically, if Figure 1 As shown, the infrared detection element 11 faces the internal space IS, so when the temperature of the internal space IS changes, the temperature of the infrared detection element 11 also changes. The temperature of the internal space IS changes, for example, by convection and heat conduction of the gas filled in the internal space IS.

[0091] When the internal space IS is sealed in a vacuum state, gas convection and heat conduction are suppressed, thereby suppressing temperature changes of the infrared detection element 11 due to temperature changes in the internal space IS. Therefore, the infrared sensor 100 of this embodiment has high sensitivity.

[0092] Next, use Figure 8 to Figure 10 , a circuit structure of the infrared sensor 100 according to the first embodiment is described.

[0093] like Figure 8 and Fig. 9As shown, the first semiconductor substrate 1 includes a plurality of column signal lines 1C, a plurality of row signal lines 1L, and a plurality of pixels PX. The plurality of column signal lines 1C are each arranged along the Y-axis direction (see Figure 1 ) are extended. One end of each of the plurality of column signal lines 1C is connected to a plurality of output terminals 4a. Each of the plurality of output terminals 4a is connected to the second semiconductor substrate 2 via each of the plurality of first connection portions 41.

[0094] Each of the plurality of row signal lines 1L extends in the X-axis direction (see Figure 1 )extend.

[0095] A plurality of pixels PX are arranged along the Y-axis direction (refer to Figure 1 ) and the X-axis direction (refer to Figure 2 ) are arranged in a two-dimensional array. Thus, a pixel array PXA is formed. Each of the plurality of pixels PX includes two infrared detection elements 11 connected to each other. One of the two infrared detection elements 11 is connected to one column signal line 1C among the plurality of column signal lines 1C. The other of the two infrared detection elements 11 is connected to one row signal line 1L among the plurality of row signal lines 1L.

[0096] The control circuit 12 includes a plurality of first switching elements S1, a plurality of first current sources P1, a first column selection circuit 106, a row selection circuit 107, and a voltage adjustment circuit 108. Each of the plurality of first switching elements S1 is connected to each of the plurality of column signal lines 1C.

[0097] Each of the plurality of first current sources P1 is connected to each of the plurality of column signal lines 1C. Each of the plurality of first current sources P1 is connected to the column signal line 1C via a first switch element S1. Each of the plurality of first current sources P1 is connected to a plurality of pixels PX via the column signal line 1C.

[0098] The first column selection circuit 106 is configured to selectively connect each of the plurality of first current sources P1 to the infrared detection element 11 via the corresponding column signal line 1C. The first column selection circuit 106 is configured to selectively connect each of the plurality of first current sources P1 to the corresponding infrared detection element 11 via the first switch element S1.

[0099] The row selection circuit 107 is configured to selectively apply voltage to the plurality of infrared detection elements 11 through the plurality of row signal lines 1L. The voltage adjustment circuit 108 is configured to apply a variable voltage to the two infrared detection elements 11 of each of the plurality of pixels PX through the plurality of row signal lines 1L. The row selection circuit 107 and the voltage adjustment circuit 108 constitute a first voltage source.

[0100] Fig.101 is a circuit diagram showing the structure of the voltage regulating circuit 108 in detail. Figure 8 and Fig. 9 In FIG. 1 , the voltage adjustment circuit 108 is shown on the right side of the paper relative to the row selection circuit 107, but in FIG. Fig.10 In FIG. 1 , the voltage adjustment circuit 108 is shown on the left side of the paper relative to the row selection circuit 107 .

[0101] like Fig.10 As shown in FIG. 1 , the voltage adjustment circuit 108 includes a plurality of second switch elements S2, a plurality of first amplifiers A1, and a plurality of second amplifiers A2. Each second switch element S2 of the plurality of second switch elements S2, each first amplifier A1 of the plurality of first amplifiers A1, and each second amplifier A2 of the plurality of second amplifiers A2 are connected to each row signal line 1L of the plurality of row signal lines 1L, respectively. The plurality of second switch elements S2, the first amplifier A1, and the plurality of second amplifiers A2 constitute a buffer circuit. The output voltage of the buffer circuit changes according to the voltage value input from the power supply of the pixel.

[0102] As described above, the first semiconductor substrate 1 has at least a unit capable of applying a voltage to the pixel array PXA and causing a current to flow in the pixel array PXA. Figure 8 As shown in FIG. 1 , as a unit for applying voltage to the pixel array PXA and causing current to flow, the first semiconductor substrate 1 includes a first current source P1, a first column selection circuit 106, a row selection circuit 107, and a voltage adjustment circuit 108. The first column selection circuit 106 and the row selection circuit 107 enable the selection of a plurality of pixels PX arranged in a two-dimensional array one by one. The row selection circuit 107 and the voltage adjustment circuit 108 enable the application of a variable voltage to the two infrared detection elements 11 of each of the plurality of pixels PX.

[0103] like Figure 8 As shown, the second semiconductor substrate 2 includes a plurality of input terminals 4b, a plurality of third switch elements S3, a plurality of fourth switch elements S4, a plurality of second current sources P2, a plurality of operational amplifiers OA, a second column selection circuit 206, and a third amplifier A3.

[0104] Each of the plurality of input terminals 4b of the signal processing circuit 21 is connected to each of the plurality of output terminals 4a of the first semiconductor substrate 1 through the first connection portion 41. Each of the third switch elements S3 of the plurality of third switch elements S3, each of the fourth switch elements S4 of the plurality of fourth switch elements S4, each of the second current sources P2 of the plurality of second current sources P2, and each of the operational amplifiers OA of the plurality of operational amplifiers OA are connected to each of the input terminals 4b of the plurality of input terminals 4b. Each of the plurality of input terminals 4b is connected to an inverting input terminal of the operational amplifier OA. Each of the plurality of input terminals 4b is connected to a non-inverting input terminal of the operational amplifier OA through the third switch element S3 and the second current source P2. Therefore, the plurality of second current sources P2 are connected to two infrared detection elements 11 of each of the plurality of pixels PX through the plurality of input terminals 4b, the plurality of first connection portions 41, the plurality of output terminals 4a, and the plurality of column signal lines 1C.

[0105] A bias voltage is applied to the non-inverting input terminal of the operational amplifier OA via the first external terminal 213. The third switch element S3 connects or disconnects the plurality of input terminals 4b and the plurality of second power supplies according to the control voltage input via the second external terminal 212. The third switch element S3 is connected (turned on) when the infrared sensor 100 operates and takes an image. The third external terminal 214 is connected to the outside.

[0106] The plurality of operational amplifiers OA are configured to operate as an integrating circuit. The second column selection circuit 206 is configured to selectively send output signals from the plurality of operational amplifiers OA to the third amplifier A3 through the plurality of fourth switch elements S4. The third amplifier A3 is configured to amplify the signal. The third amplifier A3 is configured to finally output the amplified signal from the infrared sensor 100.

[0107] When the infrared sensor 100 is in operation and photographing, the plurality of pixels PX arranged in a two-dimensional array can be selected one by one through the second column selection circuit 206 of the second semiconductor substrate 2 and the row selection circuit 107 of the first semiconductor substrate 1. When the infrared sensor 100 is in operation and photographing, the second current source P2 of the second semiconductor substrate 2 is connected to the infrared detection element 11. In addition, when the infrared sensor 100 is in operation and photographing, the first current source P1 of the first semiconductor substrate 1 is not connected to the infrared detection element 11. A variable voltage is applied to the infrared detection element 11 through the row selection circuit 107 and the voltage adjustment circuit 108.

[0108] The operational amplifier OA receives the voltage across the second current source P2 connected to the infrared detection element 11 and the voltage across the second current source P2 connected to the input terminal 4b. As a result, the third amplifier A3 finally outputs a signal from which the voltage drop distribution due to the horizontal wiring resistance has been subtracted.

[0109] The second semiconductor substrate 2 is configured to differentially amplify and output the output signals of the plurality of infrared detection elements 11 input from the first semiconductor substrate 1 through the plurality of first connection portions 41 through the integration circuit of the operational amplifier OA. The output signals of the plurality of infrared detection elements 11 are amplified and converted into digital data through an analog / digital converter (not shown), thereby being able to output a good output signal without being affected by the subsequent circuit.

[0110] In addition, the second semiconductor substrate 2 may also process the output signals of the plurality of infrared detection elements 11 in a digital signal processing circuit (not shown) after converting them into digital data through an analog / digital converter (not shown). Digital data has high noise resistance and is therefore suitable for calculation processing. The digital signal processing circuit (not shown) is mounted on the second semiconductor substrate 2.

[0111] In addition, the second semiconductor substrate 2 of the infrared sensor 100 may be fed back based on the output signal of the digital signal processing circuit (not shown) so as to be further optimally controlled. The output signal of the digital signal processing circuit (not shown) may be converted into an analog voltage signal by a digital / analog converter (not shown) and then sent to the first semiconductor substrate 1 through the first connecting portion 41. The digital / analog converter (not shown) may be mounted on the first semiconductor substrate 1. The digital / analog converter (not shown) mounted on the first semiconductor substrate 1 can transmit the signal as a digital signal.

[0112] In addition, the structure in which each of the plurality of output terminals 4a connected to each of the plurality of column signal lines 1C of the first semiconductor substrate 1 is connected to the input terminal 4b of the second semiconductor substrate 2 via the first connection portion 41 has been described, but the circuit structure of each of the first semiconductor substrate 1 and the second semiconductor substrate 2 is not limited thereto and can be appropriately selected according to the application. For example, each of the plurality of output terminals 4a connected to each of the plurality of row signal lines 1L of the first semiconductor substrate 1 may be connected to the input terminal 4b of the second semiconductor substrate 2 via the first connection portion 41.

[0113] Next, the effects of this embodiment will be described.

[0114] According to the infrared sensor 100 of this embodiment, as Figure 1As shown, the sealing frame 3 and the first connecting portion 4 are each sandwiched between the first main surface 1a and the second main surface 2a. Therefore, the sealing frame 3 and the first connecting portion 4 can be sandwiched by the first main surface 1a and the second main surface 2a. Therefore, the sealing frame 3 and the first connecting portion 4 can be sandwiched together by the first main surface 1a and the second main surface 2a. Therefore, the sealing of the internal space IS and the electrical connection of the first semiconductor substrate 1 and the second semiconductor substrate 2 can be performed together. Therefore, the increase in the manufacturing cost of the infrared sensor 100 can be suppressed.

[0115] like Figure 1 As shown, the infrared sensor 100 further includes an anti-reflection film 6. The anti-reflection film 6 is configured to prevent reflection of infrared rays IR. Therefore, compared with a case where the anti-reflection film 6 is not provided, it is possible to suppress the occurrence of stray light components due to reflected light of incident infrared rays IR. In addition, the stray light component is a component generated due to unnecessary scattering of infrared rays. Therefore, it is possible to suppress the sensitivity of the infrared sensor 100 from being reduced due to the stray light component.

[0116] like Figure 1 As shown, the second semiconductor substrate 2 includes a second substrate portion 22 and a second infrared-transmitting portion IT2. The second infrared-transmitting portion IT2 is configured to transmit infrared rays IR more than the second substrate portion 22. Therefore, compared with the case where the infrared rays IR are incident on the infrared detection element 11 through the second substrate portion 22, the intensity of the infrared rays IR incident on the infrared detection element 11 can be increased. Therefore, the sensitivity of the infrared sensor 100 can be improved.

[0117] like Figure 1 As shown in FIG. 1 , the infrared sensor 100 further includes a second connection portion 5. Therefore, compared with a case where only the sealing frame 3 and the first connection portion 4 are sandwiched between the first main surface 1a and the second main surface 2a, the load applied to the sealing frame 3 and the first connection portion 4 is dispersed. Therefore, even if a load is applied to the sealing frame 3 and the first connection portion 4, the first semiconductor substrate 1 and the second semiconductor substrate 2 can be arranged so that they face each other in parallel.

[0118] like Figure 1 As shown, the infrared sensor 100 further includes the second connecting portion 5. Therefore, the first main surface 1a and the second main surface 2a can be connected more firmly than when only the sealing frame 3 and the first connecting portion 4 are sandwiched between the first main surface 1a and the second main surface 2a.

[0119] The second connection portion 5 has a higher melting point than the first connection portion 4. Therefore, the mechanical strength of the bond between the first semiconductor substrate 1 and the second semiconductor substrate 2 can be improved.

[0120] In more detail, the first semiconductor substrate 1 and the second semiconductor substrate 2 are bonded by the sealing frame 3, the first connection part 4 and the second connection part 5 according to the following process. First, the sealing frame 3, the first connection part 4 and the second connection part 5 are arranged between the first semiconductor substrate 1 and the second semiconductor substrate 2. The sealing frame 3 and the first connection part 4 are melted by heating at a temperature higher than the melting point of the sealing frame 3 and the first connection part 4 and lower than the melting point of the second connection part 5. In a state where the first semiconductor substrate 1 and the second semiconductor substrate 2 are separated by the size of the second connection part 5, the first semiconductor substrate 1 and the second semiconductor substrate 2 are mechanically and electrically connected by the sealing frame 3 and the first connection part 4. On the other hand, when the first connection part 4 is melted, the second connection part 5 is not melted. Therefore, it is possible to suppress the strength of the second connection part 5 from being reduced due to the melting of the second connection part 5. In addition, it is possible to suppress the parallelism (uniformity of the interval) of the first semiconductor substrate 1 and the second semiconductor substrate 2 from being reduced due to the melting of the second connection part 5. Therefore, the mechanical strength of the first semiconductor substrate 1 and the second semiconductor substrate 2 can be improved. In addition, the positional deviation of the second connecting portion 5 due to melting of the second connecting portion 5 can be suppressed. Therefore, the first semiconductor substrate 1 and the second semiconductor substrate 2 can be bonded to each other with high accuracy.

[0121] The material of the sealing frame 3 is conductive. Therefore, the sealing frame 3 can be melted at the temperature at which the material of the conductive first connecting portion 4 melts. Therefore, the sealing frame 3 and the first connecting portion 4 can be melted at the same temperature. Therefore, compared with the case where the sealing frame 3 and the first connecting portion 4 melt at different temperatures, the manufacturing process can be simplified.

[0122] The material of the first connection part 4 is the same as that of the sealing frame 3. Therefore, the melting point of the first connection part 4 is the same as that of the sealing frame 3. Therefore, the sealing frame 3 and the first connection part 4 can be melted at the same temperature. Therefore, compared with the case where the sealing frame 3 and the first connection part 4 melt at different temperatures, the manufacturing process can be simplified.

[0123] like Figure 1 As shown, the internal space IS is sealed in a vacuum state. Therefore, compared with the case where the pressure in the internal space IS is atmospheric pressure, heat conduction and convection caused by gas generated in the internal space IS can be suppressed. Therefore, the reduction in thermal resistance of the internal space IS can be suppressed. As a result, it is possible to suppress heat from escaping from the infrared detection element 11 to the internal space IS through heat conduction. Therefore, the sensitivity of the infrared sensor 100 can be improved.

[0124] like Figure 1As shown, the second connection portion 5 does not electrically connect the first semiconductor substrate 1 and the second semiconductor substrate 2. Therefore, the second connection portion 5 does not contact the electrode materials of the first semiconductor substrate 1 and the second semiconductor substrate 2. Therefore, diffusion of the second connection portion 5 into the electrode materials of the first semiconductor substrate 1 and the second semiconductor substrate 2 can be suppressed.

[0125] According to the infrared sensor 100 of the modified example of the present embodiment, Figure 4 As shown, the control circuit 12 faces the signal processing circuit 21. Therefore, the size along the in-plane direction (X-axis direction and Y-axis direction) of the first semiconductor substrate 1 can be reduced compared to a case where the control circuit 12 does not face the signal processing circuit 21. Therefore, the size of the infrared sensor 100 along the X-axis direction and the Y-axis direction can be reduced.

[0126] According to the manufacturing method of the infrared sensor 100 of this embodiment, Figure 1 As shown, by sandwiching the sealing frame 3 and the first connecting portion 4 between the first main surface 1a, the infrared detection element 11 and the second main surface 2a, the internal space IS is surrounded by the first main surface 1a, the infrared detection element 11, the second main surface 2a and the sealing frame 3, and the internal space IS is sealed in a closed state. By sandwiching the sealing frame 3 and the first connecting portion 4 between the first main surface 1a, the infrared detection element 11 and the second main surface 2a, the infrared detection element 11 and the signal processing circuit 21 are electrically connected by the first connecting portion 4. Therefore, the sealing of the internal space IS and the electrical connection between the first semiconductor substrate 1 and the second semiconductor substrate 2 can be performed at the same time. As a result, the manufacturing process of the infrared sensor 100 can be simplified. Therefore, the increase in the manufacturing cost of the infrared sensor 100 can be suppressed.

[0127] like Figure 1 As shown, the internal space IS is sealed in a vacuum atmosphere by the first main surface 1a, the infrared detection element 11, the second main surface 2a and the sealing frame 3. Therefore, the internal space IS can be sealed in a vacuum state. Therefore, the sensitivity of the infrared sensor 100 can be improved.

[0128] like Figure 1 As shown in the figure, a second connection portion 5 is also prepared. The second connection portion 5 is sandwiched between the first main surface 1a and the second main surface 2a together with the sealing frame 3 and the first connection portion 4. Therefore, compared with the case where the first main surface 1a and the second main surface 2a are only sandwiched by the sealing frame 3 and the first connection portion 4, the load applied to the sealing frame 3 and the first connection portion 4 is dispersed. Therefore, the first semiconductor substrate 1 and the second semiconductor substrate 2 can be arranged in a manner that the first semiconductor substrate 1 and the second semiconductor substrate 2 face each other in parallel.

[0129] Implementation method 2.

[0130] Next, use Fig.11 , the structure of the infrared sensor 100 of Embodiment 2 is described. Unless otherwise specified, Embodiment 2 has the same structure, manufacturing method, and effects as the modified example of Embodiment 1 described above. Therefore, the same reference numerals are given to the same structures as the modified example of Embodiment 1 described above, and the description is not repeated.

[0131] like Fig.11 As shown, the second main surface 2a of the present embodiment includes a second main surface P and a recessed portion G. The second main surface P and the recessed portion G face the internal space IS. The second main surface P is a flat surface. The recessed portion G is arranged to be recessed from the second main surface P at a position facing the infrared detection element 11. Specifically, the recessed portion G is arranged to be recessed from the second main surface P at a position facing the infrared detection element 11 along the direction (Z-axis direction) in which the first semiconductor substrate 1 and the second semiconductor substrate 2 overlap. The recessed portion G overlaps with the infrared detection element 11 along the Z-axis direction. In the present embodiment, the recessed portion G is arranged in the second infrared-transmitting portion IT2.

[0132] Next, the effects of this embodiment will be described.

[0133] According to the infrared sensor 100 of this embodiment, as Fig.11 As shown, the recess G is provided so as to be recessed from the second main surface P at a position facing the infrared detection element 11. Therefore, the volume of the internal space IS is larger than when the second main surface 2a is completely flat. The larger the volume of the internal space IS, the more the temperature change of the internal space IS can be suppressed. Therefore, the sensitivity of the infrared sensor 100 can be improved.

[0134] In addition, the larger the volume of the internal space IS, the smaller the change in vacuum degree caused by the temperature change of the desorbed gas from the first semiconductor substrate 1 and the second semiconductor substrate 2. Therefore, even if the desorbed gas intrudes into the internal space IS, the change in vacuum degree due to the desorbed gas can be suppressed. The desorbed gas is a gas released from a component.

[0135] like Fig.11 As shown, the recess G is provided so as to be recessed from the second main surface P at a position facing the infrared detection element 11. Therefore, the thickness of the second semiconductor substrate 2 in the recess G is thinner than the thickness of the second semiconductor substrate 2 in a region where the recess G is not provided. That is, the second semiconductor substrate 2 is thinned in the recess G. Therefore, the second semiconductor substrate 2 has a high transmittance in the recess G. Thus, the intensity of the infrared IR incident on the infrared detection element 11 can be increased. Therefore, the sensitivity of the infrared sensor 100 can be increased.

[0136] Implementation method 3.

[0137] Next, use Fig.12 , the structure of the infrared sensor 100 of Embodiment 3 is described. Unless otherwise specified, Embodiment 3 has the same structure, manufacturing method, and effects as the modified example of Embodiment 1 described above. Therefore, the same reference numerals are given to the same structures as the modified example of Embodiment 1 described above, and the description is not repeated.

[0138] In this embodiment, infrared IR enters the infrared detection element 11 through the first rear surface 1b in the positive direction of the Z axis. The infrared detection element 11 is configured to detect infrared IR entering the infrared detection element 11 through the first rear surface 1b in the Z axis direction.

[0139] like Fig.12 As shown, the first semiconductor substrate 1 of the present embodiment includes a first substrate portion 13 and a first infrared-transmitting portion IT1. The first substrate portion 13 and the infrared-transmitting portion are configured to transmit infrared rays IR. The first infrared-transmitting portion IT1 is configured to transmit infrared rays IR more than the first substrate portion 13. The first infrared-transmitting portion IT1 faces the infrared detection element 11. The first infrared-transmitting portion IT1 is configured to overlap with the infrared detection element 11 in the Z-axis direction.

[0140] Impurities such as phosphorus (P) and boron (B) are added to the first infrared transmitting portion IT1 , for example. Thus, the first infrared transmitting portion IT1 has a resistivity of, for example, 1 Ω·cm or more.

[0141] The absorption of infrared IR by the first infrared-transmitting portion IT1 is correlated with the resistivity of the first infrared-transmitting portion IT1. Therefore, the greater the resistivity of the first infrared-transmitting portion IT1, the less the first infrared-transmitting portion IT1 absorbs infrared IR. Therefore, when the resistivity of the first infrared-transmitting portion IT1 is, for example, 1Ω·cm or more, the absorption of the infrared IR wavelength by the first semiconductor substrate 1 is suppressed. The structure of the first infrared-transmitting portion IT1 may be the same as the structure of the second infrared-transmitting portion IT2 except for the position of the first infrared-transmitting portion IT1.

[0142] Next, the effects of this embodiment will be described.

[0143] According to the infrared sensor 100 of this embodiment, as Fig.12 As shown, the first semiconductor substrate 1 includes a first substrate portion 13 and a first infrared transmitting portion IT1. The first infrared transmitting portion IT1 is configured to transmit infrared IR more than the first substrate portion 13. Therefore, compared with the case where the infrared IR is incident on the infrared detection element 11 through the first substrate portion 13, the intensity of the infrared IR incident on the infrared detection element 11 can be increased. Therefore, the sensitivity of the infrared sensor 100 can be improved.

[0144] like Fig.12 As shown, the first infrared transmitting portion IT1 is configured to overlap with the infrared detection element 11 in the Z-axis direction. Therefore, even when the infrared IR enters the first semiconductor substrate 1 from the first back surface 1b side of the first semiconductor substrate 1, the infrared IR passes through the first infrared transmitting portion IT1 and enters the infrared detection element 11. Therefore, even when the infrared IR enters the first semiconductor substrate 1 from the first back surface 1b side, the infrared detection element 11 can be detected.

[0145] Implementation method 4.

[0146] Next, use Fig.13 , the structure of the infrared sensor 100 of Embodiment 4 is described. Unless otherwise specified, Embodiment 4 has the same structure, manufacturing method, and effects as those of Embodiment 3 described above. Therefore, the same reference numerals are given to the same structures as those of Embodiment 3 described above, and the description is not repeated.

[0147] like Fig.13 As shown, the second main surface 2a of the present embodiment includes a second main surface P and a recessed portion G. The second main surface P and the recessed portion G face the internal space IS. The second main surface P is a flat surface. The recessed portion G is configured to be recessed from the second main surface P at a position facing the infrared detection element 11. Specifically, the recessed portion G is configured to be recessed from the second main surface P at a position facing the infrared detection element 11 along the direction (Z-axis direction) in which the first semiconductor substrate 1 and the second semiconductor substrate 2 overlap. The recessed portion G overlaps with the infrared detection element 11 along the Z-axis direction. It is sufficient that the recessed portion G at least partially overlaps with the infrared detection element 11 along the Z-axis direction.

[0148] Next, the effects of this embodiment will be described.

[0149] According to the infrared sensor 100 of this embodiment, as Fig.13 As shown in FIG. 1 , the recessed portion G is provided so as to be recessed from the second main surface portion P at a position facing the infrared detection element 11 . Therefore, the sensitivity of the infrared sensor 100 can be improved.

[0150] Thus, even when the infrared ray IR enters the infrared detection element 11 through the first rear surface 1 b , the sensitivity of the infrared sensor 100 can be improved.

[0151] Implementation method 5.

[0152] Next, use Fig.14, the structure of the infrared sensor 100 of the fifth embodiment is described. Unless otherwise specified, the fifth embodiment has the same structure, manufacturing method, and effects as the third embodiment described above. Therefore, the same reference numerals are given to the same structures as the third embodiment described above, and the description is not repeated. .

[0153] like Fig.14 As shown, the infrared sensor 100 of this embodiment further includes an anti-reflection film 6. The anti-reflection film 6 is arranged on the opposite side of the second semiconductor substrate 2 relative to the first main surface 1a. The anti-reflection film 6 covers the first back surface 1b. The anti-reflection film 6 is configured to prevent reflection of infrared rays IR. Except for the position where the anti-reflection film 6 is arranged, the anti-reflection film 6 can have the same structure as the anti-reflection film 6 described in Embodiment 1.

[0154] Next, the effects of this embodiment will be described.

[0155] According to the infrared sensor 100 of the present embodiment, the infrared sensor 100 further includes an anti-reflection film 6. The anti-reflection film 6 is arranged on the opposite side of the second main surface 2a relative to the first main surface 1a. Therefore, the anti-reflection film 6 covers the first back surface 1b. Therefore, even in the case where the infrared IR is incident on the infrared detection element 11 from the first back surface 1b side of the first semiconductor substrate 1, the stray light component generated due to the reflection of the infrared IR can be suppressed. Thus, the infrared IR scattered in the first semiconductor substrate 1 can be suppressed from being incident on the infrared detection element 11. In addition, even in the case where the infrared IR is incident on the infrared detection element 11 from the first back surface 1b side of the first semiconductor substrate 1, the sensitivity of the infrared sensor 100 can be improved.

[0156] Implementation method 6.

[0157] Next, use Fig.15 and Fig.16 , the structure of the infrared sensor 100 according to the sixth embodiment will be described. Fig.15 is along Fig.16 Implementation Example 6 has the same structure, manufacturing method, and effects as the above-mentioned modification of Implementation Example 1 unless otherwise specified. Therefore, the same reference numerals are given to the same structures as the above-mentioned modification of Implementation Example 1, and the description is not repeated.

[0158] like Fig.15 As shown, the second connection portion 5 of this embodiment has an outer diameter different from that of the first connection portion 4. In this embodiment, the second connection portion 5 has an outer diameter larger than that of the first connection portion 4. Fig.16As shown, each of the plurality of second connection portions 51 of the second connection part 5 has an outer diameter different from that of each of the plurality of first connection portions 41 of the first connection part 4. The second connection portion 51 has an outer diameter larger than that of the first connection portion 41.

[0159] For example, when the number of the first connection parts 41 is small, for example, 10 or more and 100 or less, the outer diameter of the second connection part 5 can be made larger than the outer diameter of the first connection part 4. Thus, when the first connection part 4 is bonded to the first semiconductor substrate 1 and the second semiconductor substrate 2, the distribution of the load applied to the first connection part 4 and the second connection part 5 is adjusted. In addition, in the present embodiment, the outer diameter of the second connection part 5 is larger than the outer diameter of the first connection part 4, but the outer diameter of the second connection part 5 may be smaller than the outer diameter of the first connection part 4.

[0160] The number of the plurality of second connection parts 51 of the second connection part 5 may be different from the number of the plurality of first connection parts 41 of the first connection part 4. In the present embodiment, the number of the plurality of second connection parts 51 is smaller than the number of the plurality of first connection parts 41.

[0161] For example, when the number of the first connection parts 41 is small, for example, 10 or more and 100 or less, the number of the second connection parts 51 may be larger than the number of the first connection parts 41. Thus, the load applied to the first connection part 4 is dispersed by the second connection part 5. In addition, in the present embodiment, the number of the plurality of second connection parts 51 is smaller than the number of the plurality of first connection parts 41, but the number of the plurality of second connection parts 51 may be larger than the number of the plurality of first connection parts 41.

[0162] Next, the effects of this embodiment will be described.

[0163] According to the infrared sensor 100 of this embodiment, as Fig.15 As shown, the second connection portion 5 has an outer diameter different from that of the first connection portion 4. Therefore, the second connection portion 5 can be configured according to the volume of the internal space IS, the outer diameter of the first connection portion 4, and the plurality of first connection portions 41 (see Fig.16 ) and the like, and adjust the outer diameter of the second connecting portion 5. Thus, when the first semiconductor substrate 1 and the second semiconductor substrate 2 are bonded, it is possible to adjust the distribution of the load applied to the sealing frame 3, the first connecting portion 4, and the second connecting portion 5. Therefore, the first semiconductor substrate 1 and the second semiconductor substrate 2 can be bonded with high precision.

[0164] like Fig.16As shown in FIG. 1 , the number of the plurality of second connection portions 51 is different from the number of the plurality of first connection portions 41. Therefore, the number of the plurality of second connection portions 51 can be adjusted according to the volume of the internal space IS, the outer diameter of the first connection portion 4, the number of the plurality of first connection portions 41, etc. Fig.15 ) and the second semiconductor substrate 2, the distribution of the load applied to the sealing frame 3, the first connecting portion 4 and the second connecting portion 5 can be adjusted. Therefore, the first semiconductor substrate 1 (see Fig.15 ) and the second semiconductor substrate 2 are bonded with high precision.

[0165] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present disclosure is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. An infrared sensor comprising: A first semiconductor substrate including a first main surface and an infrared detection element disposed on the first main surface; a second semiconductor substrate including a second main surface facing the first main surface and a signal processing circuit configured to process a signal of the infrared detection element; a sealing frame mechanically connected to the first semiconductor substrate and the second semiconductor substrate, not electrically connecting the first semiconductor substrate and the second semiconductor substrate, surrounding the infrared detection element disposed on the first main surface, and forming an internal space sealed in a sealed state with the first main surface, the infrared detection element and the second main surface; as well as The first connecting portion is provided on the first main surface outside the sealing frame and electrically connects the infrared detection element and the signal processing circuit. The internal space is sealed in a hermetically sealed state by the first main surface, the infrared detection element, the second main surface, and the sealing frame. The sealing frame and the first connecting portion are each sandwiched between the first main surface and the second main surface. The signal processing circuit is arranged in a region outside the internal space.

2. The infrared sensor according to claim 1, wherein: further comprising a second connecting portion, The second connection portion is sandwiched between the first main surface and the second main surface.

3. An infrared sensor comprising: A first semiconductor substrate including a first main surface and an infrared detection element disposed on the first main surface; a second semiconductor substrate including a second main surface facing the first main surface and a signal processing circuit configured to process a signal of the infrared detection element; a sealing frame connected to the first semiconductor substrate and the second semiconductor substrate and surrounding an internal space together with the first main surface, the infrared detection element and the second main surface; as well as a first connection portion electrically connecting the infrared detection element and the signal processing circuit; The internal space is sealed in a hermetically sealed state by the first main surface, the infrared detection element, the second main surface, and the sealing frame. The sealing frame and the first connecting portion are each sandwiched between the first main surface and the second main surface. The infrared sensor further comprises a second connecting portion. The second connecting portion is sandwiched between the first main surface and the second main surface, The second connection portion has a higher melting point than the first connection portion and the sealing frame.

4. The infrared sensor according to claim 1 or 3, further comprising: an antireflection film disposed on the side opposite to the second semiconductor substrate with respect to the first main surface, The antireflection film is configured to prevent reflection of infrared rays.

5. The infrared sensor according to claim 1 or 3, wherein: The first semiconductor substrate includes a first substrate portion and a first infrared ray transmitting portion configured to transmit infrared rays more than the first substrate portion. The first infrared transmitting portion faces the infrared detecting element.

6. The infrared sensor according to claim 1 or 3, further comprising: an antireflection film disposed on the side opposite to the first semiconductor substrate with respect to the second main surface, The antireflection film is configured to prevent reflection of infrared rays.

7. The infrared sensor according to claim 1 or 3, wherein: The second semiconductor substrate includes a second substrate portion and a second infrared-transmitting portion configured to transmit infrared rays more than the second substrate portion. The second infrared transmitting portion faces the infrared detecting element.

8. The infrared sensor according to claim 1 or 3, wherein: The second main surface includes a second main surface portion and a concave portion, The recessed portion is provided so as to be recessed from the second main surface portion at a position facing the infrared detection element.

9. The infrared sensor according to claim 3, wherein: The second connection portion is sandwiched between the first main surface and the second main surface.

10. The infrared sensor according to claim 2 or 9, wherein: The second connection portion has an outer diameter different from that of the first connection portion.

11. The infrared sensor according to claim 2 or 9, wherein: The second connection portion has a higher melting point than the first connection portion and the sealing frame.

12. The infrared sensor according to any one of claims 1 to 3 and 9, wherein: The first connection portion and the sealing frame are each made of a conductive material.

13. The infrared sensor according to any one of claims 1 to 3 and 9, wherein: The material of the first connecting portion is the same as that of the sealing frame.

14. The infrared sensor according to any one of claims 1 to 3 and 9, wherein: The internal space is sealed in a vacuum state.

15. A method for manufacturing an infrared sensor, comprising: A step of preparing a first semiconductor substrate including a first main surface and an infrared detection element disposed on the first main surface, a second semiconductor substrate including a second main surface and a signal processing circuit configured to process a signal of the infrared detection element, a sealing frame, and a first connecting portion; and A process in which an internal space sealed in a sealed state is formed by the first main surface, the infrared detection element, the second main surface and the sealing frame by sandwiching the sealing frame and the first connecting portion respectively between the first main surface, the infrared detection element and the second main surface, the sealing frame is mechanically connected to the first semiconductor substrate and the second semiconductor substrate, the sealing frame does not electrically connect the first semiconductor substrate and the second semiconductor substrate, the sealing frame surrounds the infrared detection element arranged on the first main surface, the signal processing circuit is arranged in an area outside the internal space, and the infrared detection element and the signal processing circuit are electrically connected outside the sealing frame through the first connecting portion.

16. The method for manufacturing an infrared sensor according to claim 15, wherein: The internal space is sealed in a vacuum atmosphere by the first main surface, the infrared detection element, the second main surface, and the sealing frame.

17. The method for manufacturing an infrared sensor according to claim 15 or 16, wherein: A second connection portion is also prepared. The second connection portion is sandwiched between the first main surface and the second main surface together with the sealing frame and the first connection portion.

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