Method for manufacturing an infrared sensor and infrared sensor

Abstract

To provide a method for manufacturing an infrared sensor that can simplify a manufacturing process.SOLUTION: An infrared sensor comprising an umbrella-shaped infrared absorbing section, a temperature detecting section formed on a substrate and connected to the infrared absorbing section, and a control section formed on the substrate and processing a signal related to temperature of the temperature detecting section, is manufactured by a method including detecting section forming step S10 in which the temperature detecting section is formed, sacrificial layer forming step S20 in which a sacrificial layer is formed from a metal material, wiring forming step S30 in which a sacrificial layer is molded to form a wiring layer for the control section, and infrared absorbing section forming step S40 in which the infrared absorbing section is formed on the sacrificial layer.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an infrared sensor and an infrared sensor.

Background Art

[0002] Conventionally, as a thermal infrared sensor, there is one in which an umbrella-shaped infrared absorption part is connected to a temperature detection part (see, for example, Patent Document 1). In the manufacturing method of this type of infrared sensor, a sacrificial layer is formed on a substrate on which a temperature detection part is formed, an infrared absorption part is formed on the sacrificial layer, and then the sacrificial layer is removed to form the infrared absorption part in an umbrella shape.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional method for manufacturing an infrared sensor, it is necessary to provide a dedicated sacrificial layer in order to form the infrared absorption part in an umbrella shape. Providing a dedicated sacrificial layer may complicate the process and increase the manufacturing cost.

[0005] Therefore, the present invention provides a method for manufacturing an infrared sensor and an infrared sensor that can simplify the manufacturing process.

Means for Solving the Problems

[0006] A method for manufacturing an infrared sensor according to a first aspect of the present invention comprises: an umbrella-shaped infrared absorbing section; a temperature detection section formed on a substrate and connected to the infrared absorbing section; and a control section formed on the substrate and processing a temperature signal from the temperature detection section, the method for manufacturing an infrared sensor comprising: a detection section forming step for forming the temperature detection section; a sacrificial layer forming step for forming a sacrificial layer from a metallic material; a wiring forming step for forming the wiring of the control section by shaping the sacrificial layer; and an infrared absorbing section forming step for forming the infrared absorbing section on the sacrificial layer.

[0007] According to the first embodiment, a sacrificial layer for forming an umbrella-shaped infrared absorbing portion can be formed using a film that forms the wiring of the control unit. Therefore, the manufacturing process can be simplified compared to the case where a sacrificial layer for forming an umbrella-shaped infrared absorbing portion is provided specifically for this purpose.

[0008] A second aspect of the present invention relates to a method for manufacturing an infrared sensor, wherein, in the method for manufacturing an infrared sensor according to the first aspect, the infrared sensor includes a support column connecting the infrared absorbing part and the temperature detecting part, and in the wiring formation step, through holes in the sacrificial layer in which the support column is formed may be formed.

[0009] According to the second embodiment, since the through-holes for the support column can be formed at the same time as the wiring for the control unit is formed, a dedicated process for forming the through-holes for the support column can be omitted. Therefore, an increase in the manufacturing process can be suppressed.

[0010] A third aspect of the present invention relates to a method for manufacturing an infrared sensor, wherein, in the method for manufacturing an infrared sensor according to the first or second aspect described above, a cavity is formed in the substrate that overlaps with the temperature detection portion in a plan view, and the infrared absorption portion formation step comprises a film formation step of forming a film and a patterning step of forming the film to form the infrared absorption portion, wherein a through hole is formed in the patterning step to connect the cavity to the outside.

[0011] According to the third embodiment, since through holes can be formed at the same time as the infrared absorbing portion is formed, a dedicated step for forming through holes can be omitted. Therefore, an increase in the number of manufacturing steps can be suppressed.

[0012] A fourth aspect of the present invention relates to a method for manufacturing an infrared sensor, wherein, in the method for manufacturing an infrared sensor according to the third aspect described above, the infrared sensor includes a support column connecting the infrared absorption portion and the temperature detection portion, and the through-holes may be formed in the support column and the temperature detection portion during the patterning step.

[0013] According to the fourth embodiment, when an etching solution or etching gas is introduced into a through-hole to form a cavity in the substrate, the cavity is formed so as to spread out from the support column in a plan view. For this reason, it is suitable for forming a relatively small cavity that covers the entire temperature detection unit connected to the support column.

[0014] A fifth aspect of the present invention relates to a method for manufacturing an infrared sensor, in which, in the method for manufacturing an infrared sensor according to the third or fourth aspect described above, the infrared sensor includes a support column connecting the infrared absorbing part and the temperature detecting part, and a plurality of through holes may be formed around the support column in the patterning step.

[0015] According to the fifth embodiment, when an etching solution or etching gas is introduced into a through-hole to form a cavity in the substrate, the cavity is formed to spread outwards from the through-hole towards the support column in a plan view, and also to the opposite side from the support column. For this reason, it is suitable for forming a relatively large cavity that spreads outwards from the temperature detection section in a plan view.

[0016] An infrared sensor according to a sixth aspect of the present invention comprises a substrate, a temperature detection unit formed on the substrate, a support column connected to the temperature detection unit, an umbrella-shaped infrared absorption unit connected to the temperature detection unit via the support column, and a control unit formed on the substrate for processing signals related to the temperature of the temperature detection unit, wherein the height of the support column corresponds to the thickness of the wiring included in the control unit.

[0017] According to the sixth aspect, since the distance between the temperature detection unit and the umbrella-shaped infrared absorption unit matches the film thickness of the wiring of the control unit, the sacrificial layer for forming the infrared absorption unit in an umbrella shape can be made of the same film as the wiring of the control unit. As a result, an umbrella-shaped infrared absorption unit can be formed without providing a dedicated sacrificial layer, and thus the infrared sensor can be manufactured at a low cost by simplifying the manufacturing process.

[0018] The infrared sensor according to the seventh aspect of the present invention is the infrared sensor according to the sixth aspect, wherein the support column and the infrared absorption unit are integrally formed and may be the same film as the insulating film provided on a layer above the wiring.

[0019] According to the seventh aspect, since the support column and the infrared absorption unit can be formed simultaneously with the control unit, the manufacturing process can be simplified as compared with a configuration in which the support column or the infrared absorption unit is formed by a dedicated film.

Advantages of the Invention

[0020] According to the present invention, the manufacturing process of the infrared sensor can be simplified.

Brief Description of the Drawings

[0021] [Figure 1] It is a plan view of the infrared sensor of the first embodiment. [Figure 2] It is a cross-sectional view taken along line II-II of FIG. 1. [[ID=2S]] [Figure 3] It is a cross-sectional view of the infrared sensor of the first embodiment. [Figure 4] It is a flowchart showing a manufacturing method of the infrared sensor of the first embodiment. [Figure 5] It is a cross-sectional view of the infrared sensor in the detection unit forming step of the first embodiment. [Figure 6] It is a cross-sectional view of the infrared sensor in the sacrificial layer film forming step of the first embodiment. [Figure 7] It is a cross-sectional view of the infrared sensor in the wiring forming step of the first embodiment. [Figure 8]This is a cross-sectional view of the infrared sensor in the infrared absorption section formation process of the first embodiment. [Figure 9] This is a cross-sectional view of the infrared sensor in the infrared absorption section formation process of the first embodiment. [Figure 10] This is a cross-sectional view of the infrared sensor in the infrared absorption section formation process of the first embodiment. [Figure 11] This is a cross-sectional view of the infrared sensor in the cavity formation process of the first embodiment. [Figure 12] This is a cross-sectional view of the infrared sensor in the sacrificial layer removal process of the first embodiment. [Figure 13] This is a plan view of the infrared sensor according to the second embodiment. [Figure 14] Figure 13 shows a cross-sectional view along the line XIII-XIII. [Figure 15] This is a cross-sectional view of the infrared sensor in the wiring formation process of the second embodiment. [Figure 16] This is a cross-sectional view of the infrared sensor in the infrared absorption section formation process of the second embodiment. [Figure 17] This is a cross-sectional view of the infrared sensor in the infrared absorption section formation process of the second embodiment. [Figure 18] This is a cross-sectional view of the infrared sensor in the infrared absorption section formation process of the second embodiment. [Figure 19] This is a cross-sectional view of the infrared sensor in the cavity formation process of the second embodiment. [Figure 20] This is a cross-sectional view of the infrared sensor in the sacrificial layer removal process of the second embodiment. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described below with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplication of these components may be omitted.

[0023] [First Embodiment] (Infrared sensor configuration) Figure 1 is a plan view of the infrared sensor according to the first embodiment. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. As shown in Figures 1 and 2, the infrared sensor 1 is a thermal infrared sensor. The infrared sensor 1 includes a substrate 10. Hereinafter, the thickness direction of the substrate 10 is referred to as the vertical direction. Furthermore, within the vertical direction, the side of the substrate 10 on which the sensor element described later is formed is defined as the upper side, and the opposite side is defined as the lower side.

[0024] The infrared sensor 1 comprises a substrate 10, a sensor layer 20 formed on the substrate 10, a support column 30 protruding upward from the sensor layer 20, and an umbrella-shaped infrared absorbing part 40 supported by the support column 30.

[0025] The substrate 10 is a semiconductor substrate such as silicon. A cavity 12 that is open upwards is formed on the upper surface 11 of the substrate 10.

[0026] The sensor layer 20 covers the upper surface 11 of the substrate 10. The sensor layer 20 is directly laminated onto the substrate 10. The sensor layer 20 as a whole extends in a direction perpendicular to the vertical direction. In a plan view from above, the sensor layer 20 overlaps with the cavity 12. The portion of the sensor layer 20 that overlaps with the cavity 12 in a plan view from above is the membrane 21 that is floating above the upper surface 11 of the substrate 10.

[0027] The sensor layer 20 comprises a thermopile-type sensor element consisting of a temperature detection unit 22, a peripheral unit 23, and a thermocouple (not shown). The temperature detection unit 22 is the portion demarcated by the dashed line in the figure relative to the peripheral unit 23. The temperature detection unit 22 is provided on the membrane 21 and, in a plan view, overlaps the center of the cavity 12. The entire temperature detection unit 22 is positioned inward from the opening edge of the cavity 12 in a plan view. As a result, the temperature detection unit 22 is non-contact with the substrate 10. The peripheral unit 23 is provided so as to surround the temperature detection unit 22. The peripheral unit 23 supports the temperature detection unit 22. The peripheral unit 23 covers the upper surface 11 of the substrate 10. The peripheral unit 23 is directly laminated to the substrate 10 in a location outside the cavity 12 in a plan view.

[0028] The temperature detection section 22 and the peripheral section 23 are insulating films such as silicon oxide or silicon nitride. The temperature detection section 22 and the peripheral section 23 may be formed from the same material or from different materials. At least one of the temperature detection section 22 and the peripheral section 23 may be formed from a multilayer film. In this embodiment, the temperature detection section 22 and the peripheral section 23 are integrally formed two-layer films, each having a first insulating layer 24 and a second insulating layer 25. Thermocouples are embedded in the temperature detection section 22 and the peripheral section 23. The thermocouples are positioned to straddle the boundary between the temperature detection section 22 and the peripheral section 23. The thermocouples have a hot junction and a cold junction. The hot junction is provided in the temperature detection section 22. The cold junction is provided in the peripheral section 23.

[0029] The support column 30 is positioned above the temperature detection unit 22. The support column 30 extends vertically. The lower end of the support column 30 is directly connected to the temperature detection unit 22. In a plan view, the support column 30 is positioned at the center of the cavity 12. The support column 30 is made of an insulating material. For example, the support column 30 is an insulating film such as a silicon oxide film or a silicon nitride film.

[0030] The infrared absorbing section 40 is directly connected to the upper end of the support column 30. The infrared absorbing section 40 is connected to the temperature detection section 22 via the support column 30. The infrared absorbing section 40 extends in a direction perpendicular to the vertical direction from the connection point with the support column 30. The infrared absorbing section 40 is formed in a plate shape with thickness in the vertical direction. The infrared absorbing section 40 is formed in a rectangular shape in plan view. The center of the infrared absorbing section 40 is connected to the upper end of the support column 30. The entire infrared absorbing section 40 has a substantially constant gap with respect to the upper surface of the sensor layer 20. A space is provided between the infrared absorbing section 40 and the sensor layer 20 in which no other members are arranged except for the support column 30. The infrared absorbing section 40 is an insulating film such as a silicon oxide film or a silicon nitride film. In this embodiment, the infrared absorbing section 40 is integrally formed from the same material as the support column 30. As a result, the infrared absorbing section 40 and the support column 30 have continuity.

[0031] The infrared sensor 1 has a through-hole 3 that connects the cavity 12 to the outside of the infrared sensor 1. The through-hole 3 penetrates at least the sensor layer 20. In this embodiment, the through-hole 3 penetrates the infrared absorbing section 40, the support column 30, and the sensor layer 20 together in the vertical direction. In this case, the through-hole 3 penetrates the temperature detection section 22 of the sensor layer 20.

[0032] Figure 3 is a cross-sectional view of the infrared sensor of the first embodiment, showing a different location from the one shown in Figure 2. As shown in Figure 3, the infrared sensor 1 includes a control unit 50. The control unit 50 processes the temperature signal from the temperature detection unit 22. Specifically, the control unit 50 measures the electromotive force of the thermocouple in the sensor layer 20. The control unit 50 is formed at a position offset in a plan view from the sensor area, which includes the sensor layer 20, the support column 30, and the infrared absorption unit 40.

[0033] The control unit 50 includes a transistor 51, a first insulating film 52 laminated on the transistor 51, a first wiring layer 53 laminated on the first insulating film 52, a second insulating film 54 covering the first wiring layer 53, a second wiring layer 55 laminated on the second insulating film 54, and a third insulating film 56 covering the second wiring layer 55. The transistor 51 is a MOSFET. However, the transistor 51 may have a structure other than a MOSFET. Reference numeral 57 in the figure indicates an element isolation region such as LOCOS (Local Oxidation of Silicon) that insulates the transistors 51 from each other.

[0034] The first insulating film 52 is directly laminated onto the transistor 51 and covers the gate, source, and drain of the transistor 51. The first insulating film 52 is the same film as the first insulating layer 24 of the sensor layer 20. In this embodiment, the same film is a film formed in the same process.

[0035] The first wiring layer 53 is directly laminated onto the first insulating film 52. The first wiring layer 53 is electrically connected to the electrodes of the transistor 51 through contacts in contact holes 52h formed in the first insulating film 52.

[0036] The second insulating film 54 is provided above the first wiring layer 53. In this embodiment, the upper layer is a layer deposited in a later process than the target structure. The second insulating film 54 covers the first wiring layer 53 and is directly laminated on the first insulating film 52 around the first wiring layer 53. The second insulating film 54 is the same film as the second insulating layer 25 of the sensor layer 20. As a result, the two-layer film consisting of the first insulating film 52 and the second insulating film 54 has a film thickness corresponding to the two insulating films that form the temperature detection section 22 and the peripheral section 23. The corresponding film thicknesses include not only cases where the film thicknesses are equal, but also cases where the film thicknesses differ due to differences in deposition rates during film formation caused by differences in the peripheral structure.

[0037] The second wiring layer 55 is directly laminated onto the second insulating film 54. The second wiring layer 55 is electrically connected to the first wiring layer 53 through through electrodes in contact holes 54h formed in the second insulating film 54. The thickness of the second wiring layer 55 on the second insulating film 54 corresponds to the height of the support column 30.

[0038] The third insulating film 56 is provided above the second wiring layer 55. The third insulating film 56 covers the second wiring layer 55 and is directly laminated on the second insulating film 54 around the second wiring layer 55. The third insulating film 56 is the same film as the structure consisting of the support column 30 and the infrared absorbing part 40, and has a film thickness corresponding to the structure consisting of the support column 30 and the infrared absorbing part 40.

[0039] (Method of manufacturing an infrared sensor) Figure 4 is a flowchart showing the manufacturing method of the infrared sensor according to the first embodiment. As shown in Figure 4, the manufacturing method of the infrared sensor 1 of this embodiment comprises a detection unit formation step S10, a sacrificial layer film formation step S20, a wiring formation step S30, an infrared absorption unit formation step S40, a cavity formation step S50, and a sacrificial layer removal step S60.

[0040] Figure 5 is a cross-sectional view of the infrared sensor in the detection unit formation process of the first embodiment. As shown in Figure 5, in the detection unit formation step S10, a sensor layer 20 is formed on the semiconductor substrate 70 which will become the substrate 10. That is, the temperature detection unit 22, peripheral part 23, and thermocouple are formed on the semiconductor substrate 70. Furthermore, in the detection unit formation step S10, the first insulating film 52, first wiring layer 53, second insulating film 54, and second wiring layer 55 of the control unit 50 are formed. Note that the transistor 51 of the control unit 50 is formed in a step prior to the detection unit formation step S10.

[0041] Specifically, the detection unit formation process S10 includes the following steps. First, the first insulating layer 24 of the sensor layer 20 is formed simultaneously with the first insulating film 52. Next, the hot and cold junctions of the thermocouple are formed simultaneously with the first wiring layer 53. At this time, the contacts in the contact holes 52h of the first insulating film 52 are formed together with the first wiring layer 53. Note that a part of the thermocouple may be formed before the formation of the first insulating layer 24. Finally, the second insulating layer 25 of the sensor layer 20 is formed simultaneously with the second insulating film 54. As a result, the two-layer film consisting of the first insulating film 52 and the second insulating film 54 becomes the same film as the two insulating films forming the temperature detection unit 22 and the peripheral part 23, and has corresponding film thicknesses. Note that each insulating film is subjected to a planarization treatment after film formation. Next, the sacrificial layer formation process S20 is performed.

[0042] Figure 6 is a cross-sectional view of the infrared sensor in the sacrificial layer deposition process of the first embodiment. As shown in Figure 6, in the sacrificial layer deposition process S20, a sacrificial layer 60 is deposited on the sensor layer 20. The sacrificial layer 60 is formed from a metallic material. For example, the metallic material used to form the sacrificial layer 60 is aluminum, aluminum alloy, copper, copper alloy, etc. The sacrificial layer 60 is also deposited in the formation region of the control unit 50. In the formation region of the control unit 50, the sacrificial layer 60 is deposited on the second insulating film 54. The through-electrode in the contact hole 54h of the second insulating film 54 is formed together with the sacrificial layer 60. As a result, the through-electrode has the same film type as the sacrificial layer 60. Next, the wiring formation process S30 is performed.

[0043] Figure 7 is a cross-sectional view of the infrared sensor in the wiring formation process of the first embodiment. As shown in Figure 7, in the wiring formation process S30, the sacrificial layer 60 is formed in the sensor area and the formation area of ​​the control unit 50. This forms the second wiring layer 55 of the control unit 50, and the sacrificial layer 60 in the sensor area becomes the same film as the second wiring layer 55. Furthermore, in the wiring formation process S30, through-holes 61 are formed in the sacrificial layer 60. The through-holes 61 penetrate the sacrificial layer 60 in the vertical direction. In a plan view, the through-holes 61 overlap the temperature detection unit 22. In the wiring formation process S30, the sacrificial layer 60 is formed by dry etching or the like. Next, the infrared absorption unit formation process S40 is performed.

[0044] Figures 8 to 10 are cross-sectional views of the infrared sensor in the infrared absorption section formation process of the first embodiment. As shown in Figures 8 to 10, in the infrared absorption part formation step S40, the infrared absorption part 40 is formed on the sacrificial layer 60. The infrared absorption part formation step S40 comprises, in order, a film formation step S41 and a patterning step S42.

[0045] As shown in Figure 8, in the film formation process S41, the material that forms the infrared absorbing portion 40 is deposited on the sacrificial layer 60. Hereinafter, the material that forms the infrared absorbing portion 40 will be referred to as the absorbing portion material 71. The absorbing portion material 71 is deposited on the sacrificial layer 60 so as to accumulate in the through-holes 61. This forms pillars 30 in the through-holes 61. Since the height of the pillars 30 matches the depth of the through-holes 61 in the sacrificial layer 60, the height of the pillars 30 corresponds to the film thickness of the second wiring layer 55, which is the same film as the sacrificial layer 60.

[0046] The absorption material 71 is also deposited in the formation area of ​​the control unit 50. The absorption material 71 becomes the third insulating film 56. As a result, the structure consisting of the support column 30 and the infrared absorption part 40 and the third insulating film 56 become the same film. In the film deposition process S41, the absorption material 71 is deposited by CVD or the like.

[0047] As shown in Figures 9 and 10, in the patterning step S42, the infrared absorbing portion 40 is formed by shaping the deposited absorbing portion material 71. Specifically, the patterning step S42 includes, in order, the steps of forming a resist pattern 73, shaping the absorbing portion material 71 by etching, and removing the resist material. As shown in Figure 9, in the step of forming the resist pattern 73, a resist material is coated onto the film of the absorbing portion material 71 deposited in the film deposition step S41, and the resist pattern 73 is created by lithography. As shown in Figure 10, in the step of shaping the absorbing portion material 71, the sacrificial layer 60 is used as an etching stopper layer. In the step of shaping the absorbing portion material 71, through holes 3 are formed in the film of the absorbing portion material 71 and the temperature detection portion 22. The through holes 3 penetrate the support columns 30. After that, the resist material is peeled off. Next, the cavity formation step S50 is performed.

[0048] Figure 11 is a cross-sectional view of the infrared sensor in the cavity formation process of the first embodiment. As shown in Figure 11, in the cavity formation process S50, a cavity 12 is formed in the semiconductor substrate 70. The semiconductor substrate 70 becomes substrate 10 when the cavity 12 is formed. The cavity 12 is formed by etching. The cavity 12 is formed when an etching solution or etching gas that enters the through hole 3 comes into contact with the semiconductor substrate 70. For example, in the cavity formation process S50, the cavity 12 is formed by wet etching. However, the cavity 12 may also be formed by dry etching. The cavity 12 is formed to spread out from the lower end opening of the through hole 3. Next, the sacrificial layer removal process S60 is performed.

[0049] Figure 12 is a cross-sectional view of the infrared sensor in the sacrificial layer removal process of the first embodiment. As shown in Figure 12, in the sacrificial layer removal step S60, the sacrificial layer 60 sandwiched between the sensor layer 20 and the infrared absorption section 40 is selectively removed. In the sacrificial layer removal step S60, the sacrificial layer 60 is removed by wet etching or the like. By removing the sacrificial layer 60, the infrared absorption section 40 is formed in an umbrella shape, separated from the sensor layer 20.

[0050] As described above, in this embodiment, the height of the support column 30 corresponds to the film thickness of the second wiring layer 55 included in the control unit 50. With this configuration, the distance between the temperature detection unit 22 and the umbrella-shaped infrared absorption unit 40 matches the film thickness of the second wiring layer 55, so the sacrificial layer 60 for forming the umbrella-shaped infrared absorption unit 40 can be made of the same film as the second wiring layer 55 of the control unit 50. That is, a manufacturing method for the infrared sensor 1 can be employed, comprising a sacrificial layer formation step S20 for forming the sacrificial layer 60 with a metallic material, a wiring formation step S30 for forming the second wiring layer 55 by shaping the sacrificial layer 60, and an infrared absorption unit formation step S40 for forming the infrared absorption unit 40 on the sacrificial layer 60. This makes it possible to form the sacrificial layer 60 for forming the umbrella-shaped infrared absorption unit 40 using the film for forming the second wiring layer 55. Therefore, the manufacturing process can be simplified compared to the case where a dedicated sacrificial layer for forming the umbrella-shaped infrared absorption unit is provided. Furthermore, since the infrared sensor 1 has an umbrella-shaped infrared absorbing section 40 formed without the need for a dedicated sacrificial layer, it can be manufactured at a low cost by simplifying the manufacturing process.

[0051] In the wiring formation process S30, through-holes 61 for forming the support columns 30 are formed in the sacrificial layer 60. This allows the through-holes 61 for the support columns 30 to be formed simultaneously with the formation of the second wiring layer 55, thus eliminating the need for a separate process for forming the through-holes 61 for the support columns 30. Consequently, an increase in the manufacturing process can be suppressed.

[0052] The infrared absorption section formation step S40 includes a patterning step S42 in which the film of the deposited absorption material 71 is molded to form the infrared absorption section 40. In the patterning step S42, a through hole 3 is formed that connects the cavity 12 to the outside of the infrared sensor 1. As a result, the through hole 3 can be formed at the same time as the infrared absorption section 40 is formed, so a separate step for forming the through hole 3 can be omitted. Therefore, an increase in the number of manufacturing steps can be suppressed.

[0053] In the patterning process S42, through holes 3 are formed in the support column 30 and the temperature detection unit 22. With this method, when etching solution is introduced into the through holes 3 to form a cavity 12 in the substrate 10, the cavity 12 is formed so as to spread out from the support column 30 in a plan view. For this reason, it is suitable for forming a relatively small cavity 12 that covers the entire temperature detection unit 22 connected to the support column 30.

[0054] The support column 30 and the infrared absorbing section 40 are made of the same film as the third insulating film 56, which is provided above the second wiring layer 55. With this configuration, the support column 30 and the infrared absorbing section 40 can be formed simultaneously with the control unit 50, thus simplifying the manufacturing process compared to a configuration in which the support column 30 or the infrared absorbing section 40 are formed from a dedicated film.

[0055] [Second Embodiment] Next, a second embodiment will be described with reference to Figures 13 to 20. In the first embodiment, a through hole 3 is formed in the support column 30, which connects the cavity 12 to the outside of the infrared sensor 1. In contrast, the second embodiment differs from the first embodiment in that the through hole 3A is formed avoiding the support column 30. Other than what is described below, the configuration is the same as in the first embodiment.

[0056] (Configuration of infrared sensor 1) Figure 13 is a plan view of the infrared sensor according to the second embodiment. Figure 14 is a cross-sectional view taken along line XIII-XIII in Figure 13. As shown in Figures 13 and 14, the infrared absorbing section 40 is formed in a rectangular shape in plan view, with four corners cut out. Multiple through holes 3A are formed around the support column 30 in plan view. The through holes 3A are formed on the outside of the infrared absorbing section 40 in plan view. The through holes 3A are formed at positions corresponding to the four corner cutouts of the infrared absorbing section 40 in plan view. The through holes 3A penetrate the sensor layer 20 in the vertical direction. In this embodiment, the through holes 3A penetrate only the peripheral portion 23 of the sensor layer 20.

[0057] (Method of manufacturing an infrared sensor) The method for manufacturing the infrared sensor 1 of this embodiment comprises a detection unit formation step, a sacrificial layer formation step, a wiring formation step, an infrared absorption unit formation step, a cavity formation step, and a sacrificial layer removal step. Note that the detection unit formation step and the sacrificial layer formation step are the same as in the first embodiment and therefore will not be described.

[0058] Figure 15 is a cross-sectional view of the infrared sensor in the wiring formation process of the second embodiment. As shown in Figure 15, in the wiring formation process, in addition to the through-hole 61, other through-holes 62 are formed in the sacrificial layer 60. The other through-holes 62 penetrate the sacrificial layer 60 in the vertical direction. In a plan view, the other through-holes 62 are formed around the through-hole 61. In a plan view, the other through-holes 62 overlap the peripheral portion 23 of the sensor layer 20. Next, the infrared absorption section formation process is performed.

[0059] Figures 16 to 18 are cross-sectional views of the infrared sensor in the infrared absorption section formation process of the second embodiment. The infrared absorption section formation process comprises, in order, a film deposition process and a patterning process. As shown in Figure 16, in the film deposition process, the absorption section material 71 is deposited on the sacrificial layer 60. The absorption section material 71 is deposited on the sacrificial layer 60 so as to accumulate in the through-hole 61 and other through-holes 62. This forms the support columns 30 in the through-hole 61.

[0060] As shown in Figures 17 and 18, in the patterning process, the infrared absorbing portion 40 is formed by shaping the deposited absorbing portion material 71. As shown in Figure 17, in the patterning process, a resist pattern 74 is created on the film of the absorbing portion material 71. Subsequently, as shown in Figure 18, the film of the absorbing portion material 71 is etched using the sacrificial layer 60 as an etching stopper layer. At this time, the absorbing portion material 71 deposited in the other through-holes 62 of the sacrificial layer 60 and the peripheral portion 23 of the sensor layer 20 are etched, and through holes 3A are formed in the peripheral portion 23. After that, the resist material is peeled off. Next, a cavity formation process is performed.

[0061] Figure 19 is a cross-sectional view of the infrared sensor in the cavity formation process of the second embodiment. As shown in Figure 19, in the cavity formation process, a cavity 12 is formed in the semiconductor substrate 70. The cavity 12 is formed by etching. The cavity 12 is formed when the etching solution that enters the through hole 3A comes into contact with the semiconductor substrate 70. Next, a sacrificial layer removal process is performed.

[0062] Figure 20 is a cross-sectional view of the infrared sensor in the sacrificial layer removal process of the second embodiment. As shown in Figure 20, in the sacrificial layer removal process, the sacrificial layer 60 sandwiched between the sensor layer 20 and the infrared absorption section 40 is selectively removed.

[0063] This embodiment provides the same effects as the first embodiment. In addition, in this embodiment, multiple through holes 3A are formed around the support column 30 during the patterning process. With this method, when etching solution is introduced into the through holes 3A to form a cavity 12 in the substrate 10, the cavity 12 is formed to spread from the through holes 3A towards the support column 30 in a plan view, and also to spread on the opposite side from the support column 30. For this reason, it is suitable for forming a relatively large cavity 12 that spreads outside the temperature detection unit 22 in a plan view.

[0064] It should be noted that the present invention is not limited to the embodiments described above with reference to the drawings, and various modifications are conceivable within its technical scope. For example, in the above embodiment, the temperature detection unit forms a thermopile-type sensor element, but the configuration is not limited to this. The temperature detection unit may also form a pyroelectric type or bolometer type sensor element.

[0065] Furthermore, in the above embodiment, the sacrificial layer 60 is the same film as the second wiring layer 55 electrically connected to the electrodes of the transistor 51 of the control unit 50, but the configuration is not limited to this. The sacrificial layer may be the same film as any of the multiple metal wirings of the control unit. The same applies to the film types of the support column 30 and the infrared absorbing section 40. That is, the support column and the infrared absorbing section may be the same film as the film provided above the wiring of the same film as the sacrificial layer in the control unit.

[0066] In the above embodiment, the support column 30 and the infrared absorbing section 40 are formed integrally, but the configuration is not limited to this. That is, the support column and the infrared absorbing section may be formed by different processes. In this case, it is desirable that at least one of the support column and the infrared absorbing section be the same film as the insulating film provided above the second wiring layer 55. This allows one of the support column and the infrared absorbing section to be formed simultaneously with the control unit, thus simplifying the manufacturing process compared to a configuration in which the support column and the infrared absorbing section are formed by separate films.

[0067] Furthermore, without departing from the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate. That is, both through-holes 3 and 3A may be formed in the infrared sensor. [Explanation of symbols]

[0068] 1…Infrared sensor 3,3A…Through hole 10…Substrate 12…Cavity 22…Temperature detection unit 30…Support column 40…Infrared absorption unit 50…Control unit 55…Second wiring layer (wiring) 60…Sacrificial layer 61…Through hole S10…Detection unit formation process S20…Sacrificial layer deposition process S30…Wiring formation process S40…Infrared absorption unit formation process S41…Film deposition process S42…Patterning process

Claims

1. An umbrella-shaped infrared absorbing section, A temperature detection unit formed on the substrate and connected to the infrared absorption unit, A control unit formed on the substrate and processing a temperature signal from the temperature detection unit, A method for manufacturing an infrared sensor comprising: A detection unit forming step for forming the temperature detection unit, A sacrificial layer deposition process in which a sacrificial layer is formed using a metallic material, A wiring formation step involves forming the sacrificial layer to form the wiring of the control unit, An infrared absorbing portion forming step in which the infrared absorbing portion is formed on the sacrificial layer, A method for manufacturing an infrared sensor equipped with [the necessary components].

2. The infrared sensor includes a support column connecting the infrared absorbing section and the temperature detecting section. In the wiring formation step, through holes are formed in the sacrificial layer in which the support columns are formed. A method for manufacturing an infrared sensor according to claim 1.

3. A cavity is formed in the substrate that overlaps with the temperature detection unit in a plan view. The infrared absorbing portion formation step is, The film formation process involves creating a film, A patterning step of forming the aforementioned film to form the infrared absorbing portion, It has, In the patterning process, a through hole is formed that connects the cavity to the outside. A method for manufacturing an infrared sensor according to claim 1 or claim 2.

4. The infrared sensor includes a support column connecting the infrared absorbing section and the temperature detecting section. In the patterning process, the through holes are formed in the support column and the temperature detection section. A method for manufacturing an infrared sensor according to claim 3.

5. The infrared sensor includes a support column connecting the infrared absorbing section and the temperature detecting section. In the patterning process, a plurality of through holes are formed around the support column. A method for manufacturing an infrared sensor according to claim 3.

6. circuit board and A temperature detection unit formed on the substrate, A support column connected to the temperature detection unit, An umbrella-shaped infrared absorbing unit connected to the temperature detection unit via the aforementioned support column, A control unit formed on the substrate for processing signals related to the temperature of the temperature detection unit, Equipped with, The height of the support column corresponds to the thickness of the wiring included in the control unit. Infrared sensor.

7. The support column and the infrared absorbing portion are integrally formed and are the same film as the insulating film provided above the wiring. The infrared sensor according to claim 6.

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