CN118231485A - Photoelectric conversion element and gas sensor - Google Patents

Abstract

The invention provides a photoelectric conversion element and a gas sensor, which can inhibit characteristic variation caused by deformation of a semiconductor substrate. The photoelectric conversion element is provided with: a semiconductor module (21) provided with a semiconductor element section (10) and a sealing section (20), wherein the semiconductor element section (10) has a light exit/entrance surface (10 a) from which light is emitted or entered, a semiconductor substrate (111), a semiconductor layer (112), and an electrode (113), and the sealing section (20) covers the side surface of the semiconductor element section; and an insulating layer (31) provided on one surface of the semiconductor module and covering the rewiring between the electrode and the external connection terminal, wherein the insulating layer is configured to include a 1 st insulating layer (311) and a2 nd insulating layer (312) and to have the rewiring provided therebetween, and is formed so as not to cover at least a part of the semiconductor layer or so as to cover at least a part of the semiconductor layer thinner than the thickness of the insulating layer covering the rewiring.

Description

Photoelectric conversion element and gas sensor

Technical Field

The present disclosure relates to photoelectric conversion elements and gas sensors.

Background

As the semiconductor device, an infrared receiving device (infrared sensor) that outputs a signal corresponding to received infrared light and an infrared light emitting device (infrared LED: LIGHT EMITTING diode) that emits infrared light based on input electric power are known. The quantum type infrared receiving element detects infrared rays by a photocurrent generated by absorbing infrared rays by a semiconductor having a PN junction or a PIN junction. The infrared light emitting element emits infrared light by a voltage applied in a forward direction. For example, an NDIR (non DISPERSIVE INFRARED: non-dispersive infrared) type gas sensor is sometimes used as the infrared receiving element and the infrared light emitting element. The NDIR gas sensor can measure the gas concentration using an infrared receiving element that receives infrared light in an absorption band corresponding to the detection target gas and an infrared light emitting element that emits infrared light in the absorption band. For example, patent document 1 discloses a device in which a light source for emitting infrared rays and a detector for detecting infrared rays of a specific wavelength are provided in a housing having an inner surface of an ellipsoid (an ellipsoid reflecting mirror), and the device is configured to introduce a gas to be detected into the housing.

Prior art literature

Patent literature

Patent document 1: U.S. patent application publication No. 2018/0348121 specification

Disclosure of Invention

Problems to be solved by the invention

In a device in which a semiconductor element is arranged on a substrate, stress may be applied to the semiconductor substrate. For example, the semiconductor substrate may warp due to the influence of thermal expansion or the like at the time of mounting the device. When the device is a gas sensor, there is a case where characteristic fluctuation of the gas sensor occurs due to warpage. In particular, in a small-sized gas sensor, since deformation of a semiconductor substrate has a large influence on characteristics, a technique capable of suppressing influence on a semiconductor element is desired.

The present disclosure, which has been made in view of the above, has an object to provide a photoelectric conversion element and a gas sensor capable of suppressing characteristic variations due to deformation of a semiconductor substrate.

Solution for solving the problem

(1) The photoelectric conversion element according to an embodiment of the present disclosure includes:

a semiconductor module including a semiconductor element portion having a light emitting/receiving surface from which light is emitted or received, a semiconductor substrate, a semiconductor layer, and an electrode, and a sealing portion covering a side surface of the semiconductor element portion; and

An insulating layer provided on one side of the semiconductor device and covering the rewiring between the electrode and the external connection terminal,

The insulating layer is configured to include a1 st insulating layer and a2 nd insulating layer with the rewiring interposed therebetween, and is formed so as not to cover at least part of the semiconductor layer or so as to cover at least part of the semiconductor layer thinner than the thickness of the insulating layer covering the rewiring.

(2) As an embodiment of the present disclosure, in (1),

In the case where the insulating layer is formed so as to cover at least part of the semiconductor layer thinly, the 2 nd insulating layer is not provided at the thinly covered portion of the insulating layer.

(3) As an embodiment of the present disclosure, in (1) or (2),

The photoelectric conversion element has a packaging structure of FOWLP.

(4) As an embodiment of the present disclosure, in any one of (1) to (3),

In the case where the semiconductor layer is divided into a connection region where the electrode can be arranged and a central region other than the connection region, the insulating layer is formed so as not to cover a part of the connection region or so as to cover a part of the connection region thinner than the thickness of the insulating layer covering the rewiring.

(5) As an embodiment of the present disclosure, in any one of (1) to (3),

In the case where the semiconductor layer is divided into a connection region where the electrode can be arranged and a central region other than the connection region, the insulating layer is formed so as not to cover the central region or so as to cover the central region thinly as compared with the thickness of the insulating layer covering the rewiring.

(6) As an embodiment of the present disclosure, in any one of (1) to (3),

In the case where the semiconductor layer is divided into a connection region where the electrode can be arranged and a central region other than the connection region, the insulating layer is formed so as not to cover a part of the connection region and the central region, or so as to cover a part of the connection region and the central region thinner than the thickness of the insulating layer covering the rewiring.

(7) As an embodiment of the present disclosure, in any one of the embodiments (1) to (6), the external connection terminals are plural and constitute an LGA or a BGA.

(8) As an embodiment of the present disclosure, in any one of (1) to (7),

In the case where the insulating layer is formed so as to cover at least part of the semiconductor layer thinly, the thickness of the thinly covered portion of the insulating layer is 1/2 or less of the thickness of the 1 st insulating layer and the 2 nd insulating layer added up.

(9) A gas sensor according to an embodiment of the present disclosure includes:

a light-emitting element which is the photoelectric conversion element described in any one of (1) to (7), and the light-emitting-entrance surface emits light; and

A light receiving element which is the photoelectric conversion element described in any one of (1) to (7), the light exit/entrance surface being configured to enter light,

A detected gas contained in the gas is detected based on a light receiving amount of the light emitted from the light emitting element and passing through the gas and detected by the light receiving element.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present disclosure, a photoelectric conversion element and a gas sensor capable of suppressing characteristic variations due to deformation of a semiconductor substrate can be provided.

Drawings

Fig. 1 is a schematic diagram showing an example of a configuration of a gas sensor according to an embodiment of the present disclosure.

Fig. 2 is a cross-sectional view showing a cross section of the gas sensor of fig. 1.

Fig. 3 is a plan view showing the upper surface of the gas sensor of fig. 1, from which the light guide member is removed.

Fig. 4 is a plan view showing an upper surface of the gas sensor of fig. 1.

Fig. 5 is a cross-sectional view showing a part of the gas sensor of fig. 1 including the photoelectric conversion element in an enlarged cross section.

Fig. 6 is a diagram illustrating stress applied to the photoelectric conversion element.

Fig. 7 is a plan view of the case where the photoelectric conversion element is a light emitting element.

Fig. 8 is a plan view of the case where the photoelectric conversion element is a light receiving element.

Fig. 9A is a cross-sectional view showing an example of the structure of an insulating layer of a photoelectric conversion element.

Fig. 9B is a cross-sectional view showing an example of the structure of an insulating layer of the photoelectric conversion element.

Fig. 9C is a cross-sectional view showing an example of the structure of an insulating layer of the photoelectric conversion element.

Fig. 9D is a cross-sectional view showing an example of the structure of the insulating layer of the photoelectric conversion element.

Fig. 9E is a cross-sectional view showing an example of the structure of the insulating layer of the photoelectric conversion element.

Fig. 9F is a cross-sectional view showing an example of the structure of an insulating layer of the photoelectric conversion element.

Fig. 9G is a cross-sectional view showing an example of the structure of an insulating layer of a photoelectric conversion element.

Description of the reference numerals

1. A gas sensor; 10. a semiconductor element section; 10a, a light exit entrance surface; 10b, electrode forming surface; 11. a light emitting element; 12. a light receiving element; 13. an IC; 14. a memory; 15. a light guide member; 16. an optical filter; 16a, a filter block; 17. an adhesive surface; 20. a sealing part; 21. a semiconductor component; 30. a rewiring layer; 30a, a surface; 30b, back; 31. an insulating layer; 32. rewiring; 33. a bonding pad; 40. an external connection terminal; 101. a central region; 102. a connection region; 111. a semiconductor substrate; 112. a semiconductor layer; 113. an electrode; 311. a 1 st insulating layer; 312. a 2 nd insulating layer; 1001. a gas sensor; 1010. a semiconductor element section; 1031. an insulating layer; 1040. and an external connection terminal.

Detailed Description

Hereinafter, a photoelectric conversion element and a gas sensor according to an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals. In the description of the present embodiment, the same or corresponding portions will be omitted or simplified as appropriate.

Fig. 1 is a schematic diagram showing an example of the structure of a gas sensor 1 according to the present embodiment. In fig. 1, in order to show the positions of the light emitting element 11, the light receiving element 12, and the like, the positions are shown to be transparent to the substrate. Fig. 2 is a cross-sectional view showing a cross section of the gas sensor 1 at a virtual line b in the center of fig. 1. Fig. 3 and 4 are plan views showing the upper surface of the gas sensor 1. Fig. 3 shows the gas sensor 1 with the light guide member 15 removed (transmitted).

In fig. 1 to 4, orthogonal coordinates corresponding to the orientation of the gas sensor 1 are set. The orthogonal coordinates are also used in fig. 5, 7 to 9G to be referred to later. The z-axis direction is the height direction of the gas sensor 1. The y-axis direction corresponds to the longitudinal direction of the gas sensor 1, and in the present embodiment, corresponds to the longitudinal direction of the rectangular substrate. The x-axis direction corresponds to the lateral direction (width direction) of the gas sensor 1, and in the present embodiment, corresponds to the short side direction of the rectangular substrate. Here, the substrate may have a square shape, and in this case, the x-axis direction may correspond to the direction of one side, and the y-axis direction may correspond to the direction orthogonal to the one side. Hereinafter, the positional relationship may be described using the axes of the orthogonal coordinates.

As shown in fig. 1 to 4, the gas sensor 1 includes a substrate, a light emitting element 11, a light receiving element 12, and a plurality of external connection terminals 40. In the present embodiment, the gas sensor 1 further includes: a light guide member 15 that guides light emitted from the light emitting element 11 toward the light receiving element 12; and a filter block 16a formed by resin molding the optical filter 16 provided on the emission surface of the light emitting element 11. In the present embodiment, the gas sensor 1 further includes: an IC13 (INTEGRATED CIRCUIT: integrated circuit) for controlling the operation of the light-emitting element 11 and the light-receiving element 12 and calculating the concentration of the detected gas; and a memory 14 that stores data, programs, and the like used in the IC13. At least a part of the plurality of external connection terminals 40 is electrically connected to the light emitting element 11 and the light receiving element 12. A part of the plurality of external connection terminals 40 may be electrically connected to the IC13 or the memory 14. In addition, one or both of the light emitting element 11 and the light receiving element 12 may also be directly electrically connected to the IC13. Further, if the memory 14 can be provided in an IC, the memory 14 may not be provided. In the case where the IC13 is provided outside, the gas sensor 1 may not include the IC13. In the case where the memory 14 is provided outside, the gas sensor 1 may not be provided with the memory 14.

Here, in a device in which a semiconductor element is sealed with a resin, a Package structure such as FOWLP (Fan Out WAFER LEVEL PACKAGE: fan-Out wafer level Package) or WLCSP (WAFER LEVEL CHIP Size Package: wafer level chip Size Package) is sometimes used for downsizing the device. In the present embodiment, the light emitting element 11, the light receiving element 12, the IC13, and the memory 14 are semiconductor elements, and the gas sensor 1 realizes a small-sized detection device having a FOWLP package structure. For example, the light emitting element 11 and the light receiving element 12 may each have a packaging structure of FOWLP. The rebuilt substrate is mounted with the above-described semiconductor elements and is electrically connected, and in the present embodiment, includes a rewiring layer 30 formed on the electrode formation surface side of the light emitting element 11 and the light receiving element 12. Details of the rewiring layer 30 will be described later. In the following description, the surface of the substrate on the side where the semiconductor element is provided and the light emitted or incident thereto is referred to as a surface 30a. The surface of the substrate opposite to the surface 30a and on the side where the plurality of external connection terminals 40 are located is referred to as a back surface 30b. The light-emitting element 11, the light-receiving element 12, and the like also have a substrate in which the elements are formed as a single body, and the substrate of the element is referred to as a semiconductor substrate 111 (see fig. 5). Further, a product using the gas sensor 1 as a component also has a substrate, and the substrate of the product is referred to as a product substrate. The term "on the back surface 30b" herein means not only a state where it is directly provided on the back surface 30b but also a state where it is indirectly provided on the back surface 30b. For example, the plurality of external connection terminals 40 may be provided on the back surface 30b via another layer or the like, and in such a case, the indirect arrangement is also described as "on the back surface 30b".

The light emission surface 10a (i.e., light emission surface) of the light emitting element 11 is provided on the surface 30a of the substrate, and emits light for detecting the gas to be detected. The light emitting element 11 is not particularly limited as long as it outputs light including a wavelength absorbed by the gas to be detected. In the present embodiment, the light emitted from the light emitting element 11 is infrared, but the present invention is not limited thereto. In the present embodiment, the light emitting element 11 is an LED, but other examples may be a semiconductor laser, a MEMS (Micro Electro MECHANICAL SYSTEMS: micro Electro mechanical system) heater, or the like. Here, "provided on the surface 30a" means not only the case of directly provided on the surface 30a but also the case of indirectly provided on the surface 30 a. For example, the filter block 16a may be provided on the surface 30a of the substrate via an adhesive material or the like, and such an indirect arrangement is also described as "provided on the surface 30a".

The wavelength of the infrared ray may be 2 μm to 12. Mu.m. The region of 2 μm to 12 μm has a plurality of intrinsic absorption bands in various gases, and is a band particularly suitable for use in the gas sensor 1. For example, there is an absorption band of methane at a wavelength of 3.3 μm, an absorption band of carbon dioxide at a wavelength of 4.3 μm, and an absorption band of alcohol (ethanol) at a wavelength of 9.5 μm.

The light emitting surface 10a (i.e., light incident surface) of the light receiving element 12 is provided on the surface 30a of the substrate, and receives light emitted from the light emitting element 11. The light receiving element 12 is not particularly limited as long as it has sensitivity in a frequency band including light of a wavelength absorbed by the detected gas. In the present embodiment, the light received by the light receiving element 12 is infrared, but the present invention is not limited thereto. The light receiving element 12 converts the received light into an electrical signal, and outputs the converted electrical signal. The electrical signal is output to the IC13, for example. The IC13 that receives the electric signal calculates the concentration of the gas to be detected based on the transmittance of light or the like.

The light guide member 15 guides light emitted from the light emitting surface of the light emitting element 11 toward the light receiving element 12 having the light incident surface. The light guide member 15 is an optical system of the gas sensor 1. The light guide member 15 includes an optical member and forms an optical path from the light emitting element 11 to the light receiving element 12. The optical member is, for example, a mirror, a lens, or the like. In the present embodiment, the light guide member 15 is bonded to the substrate by the bonding surface 17 of the surface 30a of the substrate, and a space into which the gas is introduced is formed. The light emitted from the light emitting element 11 passes through the gas in the space via the light guide member 15 and is received by the light receiving element 12. If the gas to be detected is contained in the space, light of a specific wavelength is absorbed according to the concentration, and therefore, the concentration of the gas to be detected can be measured by detecting the absorption amount.

The optical filter 16 is a member having a wavelength selection function. The optical filter 16 may be a band-pass filter that transmits light in the absorption band of the gas to be detected. In the present embodiment, the optical filter 16 is provided on the emission surface of the light emitting element 11, but the present invention is not limited thereto. The optical filter 16 may be provided on a light receiving surface (incident surface) of the light receiving element 12, for example.

Fig. 5 is a cross-sectional view showing a part of the gas sensor 1 of fig. 1 including the photoelectric conversion element in an enlarged cross section. The photoelectric conversion element is a light emitting element 11 or a light receiving element 12. In the description of the structure common to the light emitting element 11 and the light receiving element 12, the term of the photoelectric conversion element may be used for the description. The enlarged cross section in fig. 5 is a cross section at a virtual line intersecting the external connection terminal 40 of the light emitting element 11 or the light receiving element 12 as shown in fig. 7 or 8.

As shown in fig. 5, an electrode 113 is provided on a surface of the semiconductor element portion 10 included in the photoelectric conversion element, which surface is opposite to the light emission surface 10 a. The electrode forming surface 10b, which is the surface of the semiconductor element portion 10 on which the electrode 113 is formed, is in contact with the rewiring layer 30. The semiconductor element portion 10 is electrically connected to the redistribution layer 30 via the electrode 113.

The semiconductor substrate 111 is a substrate on which elements of the semiconductor layer 112 of the photodiode structure having a PN junction or a PIN junction can be formed. The semiconductor substrate 111 is not particularly limited as long as it has light transmittance of infrared rays or the like. The semiconductor substrate 111 may contain a material containing a semiconductor, or may be insulating. As an example, the semiconductor substrate 111 is formed of silicon (Si), gallium arsenide (GaAs), sapphire, indium phosphide (InP), or the like. In the case where the semiconductor layer 112 is formed of a material containing a narrow band gap semiconductor material (for example, inSb) including In, sb, as, al or the like, it is preferable to use a GaAs substrate as the semiconductor substrate 111 from the viewpoint of forming the semiconductor layer 112 having few lattice defects. In this case, the semiconductor substrate 111 has a high transmittance for light, and high-quality crystalline growth can be performed on the semiconductor substrate 111. The surface of the semiconductor substrate 111 on the light emission surface 10a side may be formed with irregularities or an antireflection film such as TiO ₂. The extraction of light can be improved.

The semiconductor layer 112 has a photodiode structure having a PIN junction formed of, for example, a1 st conductive semiconductor layer, an active layer, and a2 nd conductive semiconductor layer. The semiconductor layer 112 is not limited to a specific structure as long as it has a photodiode structure or an LED structure having a PIN junction or a PN junction. The semiconductor layer 112 can be formed using a known substance having sensitivity to light of a specific wavelength such as infrared light, and can be formed using InSb, for example. An electrode 113 is formed on the semiconductor layer 112.

The sealing portion 20 is made of a resin material, and covers the side surface of the semiconductor element portion 10 so as to expose the light exit surface 10a of the semiconductor element portion 10. The electrode forming surface 10b of the semiconductor element portion 10 is exposed to the rewiring layer 30. That is, in the gas sensor 1 of the present embodiment, the semiconductor element portion 10 is sealed by the sealing portion 20 except for the light emission incident surface 10a and the electrode forming surface 10 b. The portion including the semiconductor element portion 10 and the sealing portion 20 is sometimes referred to herein as a semiconductor element 21. The sealing portion 20 may be formed so as to be capable of emitting light such as infrared rays into the semiconductor layer 112 via the semiconductor substrate 111, and the surface to be covered is not particularly limited. For example, the sealing portion 20 may cover a part of the electrode forming surface 10b of the semiconductor element portion 10, or may not cover a part of the side surface of the semiconductor element portion 10. The upper surface of the portion of the sealing portion 20 covering the side surface of the semiconductor element portion 10 may be lower than the light emission incident surface 10a, or may be flush with the light emission incident surface 10 a.

As the sealing portion 20, a resin material having a linear expansion coefficient similar to that of the rewiring layer 30 is preferably used from the viewpoints of mass productivity, mechanical strength, and stress of the semiconductor element portion 10. The sealing portion 20 may be formed of a resin material such as epoxy resin, for example.

The material constituting the sealing portion 20 may contain a filler, unavoidable impurities, and the like, in addition to a resin material such as an epoxy resin. As the filler, for example, silica, alumina, or the like is preferably used.

The rewiring layer 30 is formed on the electrode formation surface 10b side of the semiconductor element portion 10 and the sealing portion 20. The rewiring layer 30 includes: an insulating layer 31 including a1 st insulating layer 311 and a 2 nd insulating layer 312 with the rewiring 32 interposed therebetween; a rewiring 32 electrically connected to the electrode 113 of the semiconductor element section 10; and a pad 33 for connecting the external connection terminal 40. In the present embodiment, the rewiring 32 is connected to the electrode 113, and the rewiring 32 is connected to the external connection terminal 40. The insulating layer 31 is provided on one surface of the semiconductor module 21, and covers at least the rewiring 32 between the electrode 113 and the external connection terminal 40.

The 1 st insulating layer 311 is formed on the electrode forming surface 10b side of the semiconductor element portion 10 and the sealing portion 20. The 1 st insulating layer 311 is formed of a material having small warpage, excellent adhesion to the rewiring 32, and high heat resistance, specifically, a resin material such as polyimide. The 1 st insulating layer 311 has an opening penetrating the 1 st insulating layer 311 at the position of the electrode 113 of the semiconductor element portion 10. The rewiring 32 can be electrically connected to the electrode 113 via the opening.

The rewiring 32 is provided between the 1 st insulating layer 311 and the 2 nd insulating layer 312. The re-wiring 32 covers the surface of the electrode 113 exposed from the opening of the 1 st insulating layer 311, extending from the sidewall of the opening to the pad 33 on the surface of the 1 st insulating layer 311.

The redistribution line 32 may be configured such that a conductor layer is formed on a base layer formed by electroless plating or sputtering, for example. The base layer also functions to improve adhesion between the 1 st insulating layer 311 and the conductor layer. The base layer is formed of copper (Cu), for example. The conductor layer is formed by, for example, electrolytic plating. The conductor layer is formed of copper (Cu), for example.

The 2 nd insulating layer 312 is formed on the surface of the 1 st insulating layer 311. The 2 nd insulating layer 312 is formed of a resin material such as polyimide, for example, similarly to the 1 st insulating layer 311. The 2 nd insulating layer 312 has an opening penetrating the 2 nd insulating layer 312 in a region which does not overlap with the opening of the 1 st insulating layer 311 in a plan view. The pad 33 can be electrically connected to the rewiring 32 via the opening. The 1 st insulating layer 311 and the 2 nd insulating layer 312 may be formed of the same material, in which case the insulating layer at a height from the semiconductor element 21 to the side of the semiconductor element 21 of the rewiring layer 32 is the 1 st insulating layer 311, and the insulating layer at the side opposite to the semiconductor element 21 from the side of the semiconductor element 21 of the rewiring layer 32 is the 2 nd insulating layer 312.

The pad 33 is provided for connecting the external connection terminal 40 to the rewiring 32. The pad 33 is formed of, for example, a laminated film of a Ni layer and an Au layer. The pad 33 covers the surface of the re-wiring 32 exposed from the opening of the 2 nd insulating layer 312.

The external connection terminal 40 is connected to the pad 33, and is electrically connected to the rewiring 32 exposed from the opening of the 2 nd insulating layer 312. In the present embodiment, the external connection terminals 40 are plural and constitute an LGA (LAND GRID ARRAY: land grid array). However, the shape of the external connection terminal 40 is not limited. The external connection terminals 40 are solder balls, for example. For example, the plurality of external connection terminals 40 may constitute a BGA (Ball GRID ARRAY: ball grid array).

The gas sensor 1 includes a light emitting element 11 and a light receiving element 12, and detects a detected gas contained in the gas based on a light receiving amount of light emitted from the light emitting element 11, passing through the gas, and detected by the light receiving element 12. The light emitting element 11 and the light receiving element 12 each have the structure of the semiconductor element section 10 described above. In the light-emitting element 11, the light-emitting entrance surface 10a of the semiconductor element portion 10 emits light. In the light receiving element 12, the light exit/entrance surface 10a of the semiconductor element portion 10 receives light. The gas sensor 1 is used as a component of a product such as a measuring device, for example, and when mounted on a product board, the plurality of external connection terminals 40 are soldered at predetermined positions on the product board by reflow soldering.

Conventionally, an optical device substrate is biased by the influence of thermal expansion due to reflow soldering and shrinkage due to subsequent cooling when the optical device is mounted, and as a result, the optical element may be deformed, and the characteristics of the optical device may be changed. For example, as shown in the upper diagram of fig. 6, when the temperature of the small-sized gas sensor 1001 in which the external connection terminal 1040 of the conventional structure is an LGA is lowered after reflow, the LGA package is contracted by having a linear expansion coefficient larger than that of the product substrate. As a result, a stress is generated that pulls toward the external connection terminal 1040 side connected to the product substrate. Since the insulating layer 1031 connected to the external connection terminals 1040 on both sides covers the semiconductor element portion 1010 of the photoelectric conversion element, stress is applied to the semiconductor element portion 1010 via the insulating layer 1031. Then, the region of the semiconductor element portion 1010 that is involved in receiving the emitted light may be pulled toward the plurality of external connection terminals 1040 and deformed, and the gas sensor 1 may have a characteristic change.

In the gas sensor 1 of the present embodiment, the insulating layer 31 is formed so as not to cover at least part of the semiconductor layer 112 or so as to cover at least part of the semiconductor layer 112 thinner than the thickness of the insulating layer 31 covering the rewiring 32 with respect to the semiconductor element portion 10 of the photoelectric conversion element. For example, as shown in fig. 6, the insulating layer 31 is separated so as not to cover the region of the semiconductor layer 112 which is involved in receiving the emitted light. Therefore, the stress of pulling the semiconductor element portion 10 toward the external connection terminal 40 is reduced, and the deformation of the semiconductor substrate 111 is suppressed, so that the occurrence of characteristic fluctuation of the gas sensor 1 can be suppressed.

Several examples of forming the insulating layer 31 are described below. Fig. 7 is a plan view of the case where the photoelectric conversion element is the light emitting element 11. As shown in fig. 7, the semiconductor layer 112 of the light-emitting element 11 can be divided into a connection region 102 where the electrode 113 can be arranged and a central region 101 other than the connection region 102. The central region 101 is a region of the semiconductor layer 112 that is involved in receiving emitted light. In particular, when the central region 101 is pulled in different directions and deformed, the gas sensor 1 undergoes characteristic fluctuation. Thus, by reducing the stress applied to the central region 101 or not applying the stress to the central region 101 or making the stress applied to the central region 101 mainly one direction, the characteristic variation of the gas sensor 1 can be suppressed. Fig. 8 is a plan view of the case where the photoelectric conversion element is the light receiving element 12. As shown in fig. 8, in the light receiving element 12, the semiconductor layer 112 can also be divided into the connection region 102 and the central region 101.

Fig. 9A to 9G are cross-sectional views showing an example of the structure of the insulating layer 31 of the photoelectric conversion element (i.e., the light emitting element 11 or the light receiving element 12). The cross section of the photoelectric conversion element in fig. 9A to 9G is a cross section at a virtual line intersecting the external connection terminal 40 as shown in fig. 7 or 8.

As shown in fig. 9A, the insulating layer 31 may be formed so as not to cover a part of the connection region 102. Since the insulating layers 31 are separated, the stress applied to the central region 101 can be made mainly in one direction. In the example of fig. 9A, the stress in the positive x-axis direction is applied to the central region 101, but since the insulating layer 31 is separated, the stress in the negative x-axis direction is hardly applied. Therefore, the deformation of the semiconductor substrate 111 is suppressed, and the occurrence of characteristic fluctuation of the gas sensor 1 can be suppressed. In the semiconductor element portion 10 of the photoelectric conversion element, a portion not covered with the insulating layer 31 is in contact with gas (air), and the reflectance is increased as compared with the case of being in contact with the insulating layer 31. Therefore, light going in the negative z-axis direction is reflected at a portion in contact with the gas and returned to the light emission entrance surface 10a or the semiconductor layer 112, and therefore, the light emission efficiency of the light emitting element 11 or the light receiving sensitivity of the light receiving element 12 can be improved.

As shown in fig. 9B, the insulating layer 31 may be formed so as to cover a part of the connection region 102 thinner than the thickness of the insulating layer 31 covering the rewiring 32. Even if the insulating layer 31 is not completely separated, the stress applied to the central region 101 can be reduced by locally thinning it. Here, the thickness of the insulating layer 31 covering the rewiring 32 is shown by "T" in fig. 5, and is the thickness obtained by adding up the 1 st insulating layer 311 and the 2 nd insulating layer 312. In the case where the insulating layer 31 is formed so as to cover at least part of the semiconductor layer 112 thinly, it is preferable that the thickness of the thinly covered portion of the insulating layer 31 is 1/2 or less (T/2 or less) of the thickness of the 1 st insulating layer 311 and the 2 nd insulating layer 312 added up. In the example of fig. 9B, the thickness of the 1 st insulating layer 311 is equal to or less than the thickness of the 2 nd insulating layer 312. Further, the insulating layer 31 covers a part of the connection region 102 in a thin manner, and is covered with only the 1 st insulating layer 311, and is T/2 or less.

As shown in fig. 9C, the insulating layer 31 may be formed so as not to cover the central region 101. In this way, since the insulating layer 31 is separated, stress can be applied to the central region 101. Therefore, the deformation of the semiconductor substrate 111 is suppressed, and the occurrence of characteristic fluctuation of the gas sensor 1 can be suppressed. Further, as in the case of fig. 9A, the light emission efficiency of the light emitting element 11 or the light receiving sensitivity of the light receiving element 12 can be improved.

As shown in fig. 9D, the insulating layer 31 may be formed so as to cover the central region 101 thinner than the thickness of the insulating layer 31 covering the rewiring 32. Even if the insulating layer 31 is not completely separated, the stress applied to the central region 101 can be reduced by locally thinning it. Here, as in fig. 9B, the thickness of the portion of the insulating layer 31 that is thinly covered is preferably 1/2 or less (T/2 or less) of the thickness of the 1 st insulating layer 311 and the 2 nd insulating layer 312 added up. In the example of fig. 9D, the insulating layer 31 is not provided with the 2 nd insulating layer 312 at a portion where the central region 101 is thinly covered, and is covered only with the 1 st insulating layer 311. Therefore, the thickness of the portion of the insulating layer 31 that thinly covers the central region 101 is T/2 or less.

As shown in fig. 9E, the insulating layer 31 may be formed so as not to cover the local and central regions 101 of the connection region 102. In this way, since the insulating layer 31 is separated, stress can be applied to the central region 101. Therefore, the deformation of the semiconductor substrate 111 is suppressed, and the occurrence of characteristic fluctuation of the gas sensor 1 can be suppressed. Further, as in the case of fig. 9A, the light emission efficiency of the light emitting element 11 or the light receiving sensitivity of the light receiving element 12 can be improved.

As shown in fig. 9F, the insulating layer 31 may be formed so as to cover the local and central regions 101 of the connection region 102 thinner than the thickness of the insulating layer 31 covering the rewiring 32. Even if the insulating layer 31 is not completely separated, the stress applied to the central region 101 can be reduced by locally thinning it. Here, as in fig. 9B, the thickness of the portion of the insulating layer 31 that is thinly covered is preferably 1/2 or less (T/2 or less) of the thickness of the 1 st insulating layer 311 and the 2 nd insulating layer 312 added up. In the example of fig. 9F, the insulating layer 31 covers only the 1 st insulating layer 311 in a portion where the local and central regions 101 of the connection region 102 are thinly formed, and T/2 or less.

As shown in fig. 9G, the insulating layer 31 may be formed so as to cover the central region 101 and not to cover a part of the connection region 102, as compared with the thickness of the insulating layer 31 covering the rewiring 32. In this way, the stress applied to the central region 101 can be reduced by locally thinning it. Here, as in fig. 9B, the thickness of the portion of the insulating layer 31 that is thinly covered is preferably 1/2 or less (T/2 or less) of the thickness of the 1 st insulating layer 311 and the 2 nd insulating layer 312 added up. In the example of fig. 9G, the insulating layer 31 covers the central region 101 thinly, and is covered with only the 1 st insulating layer 311, and is T/2 or less. Further, since the insulating layers 31 are separated, the stress applied to the central region 101 can be made mainly in one direction. In the example of fig. 9G, the stress in the positive x-axis direction is applied to the central region 101, but since the insulating layer 31 is separated, the stress in the negative x-axis direction is hardly applied. Therefore, the deformation of the semiconductor substrate 111 is suppressed, and the occurrence of characteristic fluctuation of the gas sensor 1 can be suppressed. In the semiconductor element portion 10 of the photoelectric conversion element, a portion not covered with the insulating layer 31 is in contact with gas (air), and the reflectance is increased as compared with the case of being in contact with the insulating layer 31. Therefore, light going in the negative z-axis direction is reflected at a portion in contact with the gas and returned to the light emission entrance surface 10a or the semiconductor layer 112, and therefore, the light emission efficiency of the light emitting element 11 or the light receiving sensitivity of the light receiving element 12 can be improved.

As described above, according to the above-described configuration, the photoelectric conversion element and the gas sensor 1 of the present embodiment can suppress characteristic variations due to deformation of the semiconductor substrate 111, as compared with the conventional configuration.

For the embodiments of the present disclosure, description has been made based on the drawings and examples, but it is noted that various modifications or changes will be readily made based on the present disclosure by those skilled in the art. Thus, it is noted that the above-described variations or modifications are included in the scope of the present disclosure. For example, functions and the like included in each structural part and the like can be rearranged so as not to be in a theoretical contradiction, and a plurality of structural parts and the like can be combined into one or divided.

Claims (9)

1. A photoelectric conversion element, wherein,

The photoelectric conversion element includes:

a semiconductor module including a semiconductor element portion having a light emitting/receiving surface from which light is emitted or received, a semiconductor substrate, a semiconductor layer, and an electrode, and a sealing portion covering a side surface of the semiconductor element portion; and

An insulating layer provided on one side of the semiconductor device and covering the rewiring between the electrode and the external connection terminal,

The insulating layer is configured to include a1 st insulating layer and a2 nd insulating layer with the rewiring interposed therebetween, and is formed so as not to cover at least part of the semiconductor layer or so as to cover at least part of the semiconductor layer thinner than the thickness of the insulating layer covering the rewiring.

2. The photoelectric conversion element according to claim 1, wherein,

In the case where the insulating layer is formed so as to cover at least part of the semiconductor layer thinly, the 2 nd insulating layer is not provided at the thinly covered portion of the insulating layer.

3. The photoelectric conversion element according to claim 1, wherein,

The photoelectric conversion element has a packaging structure of FOWLP.

4. The photoelectric conversion element according to any one of claims 1 to 3, wherein,

In the case where the semiconductor layer is divided into a connection region where the electrode can be arranged and a central region other than the connection region, the insulating layer is formed so as not to cover a part of the connection region or so as to cover a part of the connection region thinner than the thickness of the insulating layer covering the rewiring.

5. The photoelectric conversion element according to any one of claims 1 to 3, wherein,

In the case where the semiconductor layer is divided into a connection region where the electrode can be arranged and a central region other than the connection region, the insulating layer is formed so as not to cover the central region or so as to cover the central region thinly as compared with the thickness of the insulating layer covering the rewiring.

6. The photoelectric conversion element according to any one of claims 1 to 3, wherein,

In the case where the semiconductor layer is divided into a connection region where the electrode can be arranged and a central region other than the connection region, the insulating layer is formed so as not to cover a part of the connection region and the central region, or so as to cover a part of the connection region and the central region thinner than the thickness of the insulating layer covering the rewiring.

7. The photoelectric conversion element according to any one of claims 1 to 3, wherein,

The external connection terminals are plural and constitute an LGA or BGA.

8. The photoelectric conversion element according to any one of claims 1 to 3, wherein,

In the case where the insulating layer is formed so as to cover at least part of the semiconductor layer thinly, the thickness of the thinly covered portion of the insulating layer is 1/2 or less of the thickness of the 1 st insulating layer and the 2 nd insulating layer added up.

9. A gas sensor, wherein,

The gas sensor includes:

a light emitting element which is the photoelectric conversion element according to any one of claims 1 to 3, wherein the light exit/entrance surface emits light; and

A light receiving element which is the photoelectric conversion element according to any one of claims 1 to 3, wherein the light exit/entrance surface is configured to enter light,

A detected gas contained in the gas is detected based on a light receiving amount of the light emitted from the light emitting element and passing through the gas and detected by the light receiving element.