US-12622085-B2 - Gas sensor

US12622085B2US 12622085 B2US12622085 B2US 12622085B2US-12622085-B2

Abstract

Provided is a gas sensor that can suppress characteristic variation caused by deformation of a semiconductor substrate. The gas sensor ( 1 ) includes a substrate (redistribution layer 30 ), a light-emitting element ( 11 ) provided at a front surface ( 30 a ) or embedded in the substrate, a light-receiving element ( 12 ) that is provided at the front surface or embedded in the substrate and that receives light emitted from the light-emitting element, and a plurality of external connection terminals ( 40 ) at a rear surface ( 30 b ) that is an opposite surface to the front surface of the substrate. At least a portion of the plurality of external connection terminals is electrically connected to the light-emitting element and the light-receiving element. The plurality of external connection terminals is arranged such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two external connection terminals.

Inventors

Toshiaki Fukunaka
Takaaki Furuya

Assignees

ASAHI KASEI MICRODEVICES CORPORATION

Dates

Publication Date: 20260505
Application Date: 20230309
Priority Date: 20220318

Claims (10)

1 . A gas sensor comprising: a substrate; a light-emitting element provided at a front surface that is one surface of the substrate or embedded in the substrate; a light-receiving element that is provided at the front surface of the substrate or embedded in the substrate and that receives light emitted from the light-emitting element; and a plurality of external connection terminals at a rear surface that is an opposite surface to the front surface of the substrate, with at least a portion of the plurality of external connection terminals electrically connected to the light-emitting element and the light-receiving element, wherein the plurality of external connection terminals is arranged such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two external connection terminals, the center of gravity of the substrate is located, in plan view, within a region in which the plurality of external connection terminals is arranged.
2 . The gas sensor according to claim 1 , wherein the plurality of external connection terminals is arranged in a region that is in one direction relative to each of the light-emitting element and the light-receiving element in plan view.
3 . The gas sensor according to claim 1 , wherein the light-emitting element and the light-receiving element are partially covered by a seal.
4 . The gas sensor according to claim 1 , wherein the substrate includes a redistribution layer formed at an electrode formation surface side of the light-emitting element and the light-receiving element, and the light-emitting element and the light-receiving element are electrically connected to at least a portion of the plurality of external connection terminals via the redistribution layer.
5 . The gas sensor according to claim 1 , further comprising an optical filter provided at an emission surface of the light-emitting element or a reception surface of the light-receiving element.
6 . The gas sensor according to claim 1 , wherein the plurality of external connection terminals is an LGA or a BGA.
7 . The gas sensor according to claim 1 , wherein the light-emitting element and the light-receiving element are embedded in the substrate, and a surface opposite to an electrode formation surface of the light-emitting element and the light-receiving element is exposed from the substrate.
8 . A gas sensor comprising: a substrate; a light-emitting element provided at a front surface that is one surface of the substrate or embedded in the substrate; a light-receiving element that is provided at the front surface of the substrate or embedded in the substrate and that receives light emitted from the light-emitting element; a light guide that guides light emitted from the light-emitting element to the light-receiving element, and a plurality of external connection terminals at a rear surface that is an opposite surface to the front surface of the substrate, with at least a portion of the plurality of external connection terminals electrically connected to the light-emitting element and the light-receiving element, wherein the plurality of external connection terminals is arranged such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two external connection terminals, and the light guide is adhered to the substrate at an adhesion surface of the front surface of the substrate, and the adhesion surface is provided such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two points in the adhesion surface.
9 . The gas sensor according to claim 8 , wherein the adhesion surface is included in a region of the front surface that corresponds to a region where the plurality of external connection terminals is arranged at the rear surface.
10 . A gas sensor comprising: a substrate; a light-emitting element provided at a front surface that is one surface of the substrate or embedded in the substrate; a light-receiving element that is provided at the front surface of the substrate or embedded in the substrate and that receives light emitted from the light-emitting element; and a plurality of external connection terminals at a rear surface that is an opposite surface to the front surface of the substrate, with at least a portion of the plurality of external connection terminals electrically connected to the light-emitting element and the light-receiving element, wherein the plurality of external connection terminals is arranged such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two external connection terminals, an integrated circuit that computes a concentration of a gas is located, in plan view, within a region in which the plurality of external connection terminals is arranged.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority of Japanese Patent Application No. 2022-044703 (filed Mar. 18, 2022) and Japanese Patent Application No. 2023-031414 (filed Mar. 1, 2023), the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to a gas sensor. BACKGROUND An infrared light-receiving element (infrared sensor) that outputs a signal in accordance with received infrared light and an infrared light-emitting element (infrared light-emitting diode (LED)) that emits infrared light in response to input electrical power are known semiconductor elements. A quantum infrared light-receiving element detects infrared light through photoelectric current generated when a semiconductor having a pn junction or pin junction absorbs infrared light. An infrared light-emitting element emits infrared light through voltage applied in a forward direction. Infrared light-receiving elements and infrared light-emitting elements may be used in non-dispersive infrared (NDIR) gas sensors, for example. An NDIR gas sensor can measure gas concentration using an infrared light-receiving element that receives infrared light of an absorption wavelength band in accordance with a detection target gas and an infrared light-emitting element that emits infrared light of this absorption wavelength band. For example, Patent Literature (PTL) 1 discloses a small NDIR gas sensor that is covered by a cap having a mirror provided in an inner part and that has constituent components arranged on a substrate. CITATION LIST Patent Literature PTL 1: WO 2018/222764 A1 SUMMARY In a device having a configuration in which a semiconductor element is arranged on a substrate, a semiconductor substrate may also be subjected to stress. For example, warping of the semiconductor substrate may occur under the influence of thermal expansion during device mounting or the like. In a case in which the device is a gas sensor, this warping may cause characteristic variation of the gas sensor. Particularly with regard to small gas sensors, deformation of a semiconductor substrate has a significant effect on characteristics, and thus there is demand for a technique that can suppress the effect on semiconductor elements. In view of the situation set forth above, an object of the present disclosure is to provide a gas sensor that can suppress characteristic variation caused by deformation of a semiconductor substrate. (1) A gas sensor according to an embodiment of the present disclosure comprises: a substrate;a light-emitting element provided at a front surface that is one surface of the substrate or embedded in the substrate;a light-receiving element that is provided at the front surface of the substrate or embedded in the substrate and that receives light emitted from the light-emitting element; anda plurality of external connection terminals at a rear surface that is an opposite surface to the front surface of the substrate, with at least a portion of the plurality of external connection terminals electrically connected to the light-emitting element and the light-receiving element, whereinthe plurality of external connection terminals is arranged such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two external connection terminals. (2) As an embodiment of the present disclosure, in the foregoing (1), the plurality of external connection terminals is arranged in a region that is in one direction relative to each of the light-emitting element and the light-receiving element in plan view. (3) As an embodiment of the present disclosure, in the foregoing (1) or (2), the light-emitting element and the light-receiving element are partially covered by a seal. (4) As an embodiment of the present disclosure, in any one of the foregoing (1) to (3), the substrate includes a redistribution layer formed at an electrode formation surface side of the light-emitting element and the light-receiving element, and the light-emitting element and the light-receiving element are electrically connected to at least a portion of the plurality of external connection terminals via the redistribution layer. (5) As an embodiment of the present disclosure, in any one of the foregoing (1) to (4), the gas sensor further comprises a light guide that guides light emitted from the light-emitting element to the light-receiving element, wherein the light guide is adhered to the substrate at an adhesion surface of the front surface of the substrate, and the adhesion surface is provided such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two points in the adhesion surface. (6) As an embodiment of the present disclosure, in the foregoing (5), the adhesion surface is included in a region of the front surface that corresponds to a region where the plurality of external connection te