Gas Sensors

Abstract

To provide a gas sensor having a small size and enabling high-precision measurement.SOLUTION: A gas sensor 1 includes a light receiving element 10, a light emitting element 20, an integrated circuit 30, a lead frame 40, and a sealing member 80 configured to seal these into a package. The lead frame 40 has at least one die pad portion 41 and a plurality of terminal portions 42, the die pad portion 41 includes a first region 41(R1) having a first thickness and a second region 41(R2) having a second thickness thinner than the first thickness, the integrated circuit 30 is disposed on the second region 41(R2) of the die pad portion 41 and is electrically connected to at least one of the plurality of terminal portions 42.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas sensor. [Background technology]

[0002] Conventionally, non-dispersive infrared absorption optical concentration measuring devices have been known as gas measuring devices that measure the concentration of a target gas in the atmosphere. These devices utilize the fact that different types of gas absorb different wavelengths of infrared light and measure the gas concentration by detecting the amount of absorption. For example, Patent Document 1 discloses a gas sensor having a light receiving element and a light emitting element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-136154 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, it is not known what type of gas sensor is preferable that includes an integrated circuit for calculating gas concentration in addition to a light receiving element and a light emitting element, and in particular, no gas sensor that is small and capable of performing high-precision measurement is known. That is, an object of the present invention is to provide a small gas sensor that enables highly accurate measurement. [Means for solving the problem]

[0005] A gas sensor according to one embodiment of the present invention is a gas sensor comprising a light receiving element, a light emitting element, an integrated circuit, a lead frame, and a sealing member for packaging these elements, wherein the lead frame has at least one die pad portion and a plurality of terminal portions, at least the die pad portion has a first region having a first thickness and a second region having a second thickness thinner than the first thickness, and the integrated circuit is disposed on the second region of the die pad portion and is electrically connected to at least one of the plurality of terminal portions.

[0006] Furthermore, a gas sensor according to another embodiment of the present invention is a gas sensor comprising a light receiving element, a light emitting element, an integrated circuit, a lead frame, and a sealing member for packaging these elements, wherein the lead frame has at least one die pad portion and a plurality of terminal portions, the light emitting element is not directly electrically connected to the light receiving element and the integrated circuit, but is electrically connected to at least one of the plurality of terminal portions, the light receiving element is electrically connected to the integrated circuit and is disposed on the opposite side of the integrated circuit from the light emitting element, and the integrated circuit is electrically connected to at least one of the plurality of terminal portions.

[0007] Furthermore, a gas sensor according to another embodiment of the present invention is a gas sensor including a light receiving element, a light emitting element, an integrated circuit, a lead frame, and a sealing member for packaging these elements, wherein the lead frame has at least one die pad portion and a plurality of terminal portions, at least the die pad portion has a first region having a first thickness and a second region having a second thickness thinner than the first thickness, the integrated circuit is disposed on the second region of the die pad portion, the light emitting element is electrically connected to at least one of the plurality of terminal portions, the light receiving element is electrically connected to the integrated circuit and is disposed on the opposite side of the integrated circuit to the light emitting element, the integrated circuit is electrically connected to at least one of the plurality of terminal portions, the first region of the die pad portion is disposed around the second region, and the second region is disposed so as to surround a portion of an end of the first region.

[0008] Furthermore, a gas sensor according to another embodiment of the present invention is a gas sensor comprising a light receiving element, a light emitting element, an integrated circuit, a lead frame, and a sealing member for packaging these elements, wherein the lead frame has at least one die pad portion and a plurality of terminal portions, the light receiving element is electrically connected to the integrated circuit, the plurality of terminal portions are arranged in a line along the die pad portion on both sides of the die pad portion, the integrated circuit is electrically connected to at least one of the plurality of terminal portions, and at least one of the terminal portions electrically connected to the integrated circuit has a region extending in a second direction intersecting a direction in which the plurality of terminal portions are arranged between the integrated circuit and the light emitting element, and a region extending in a first direction intersecting the second direction and approaching the integrated circuit, and has a bonding region at an end of the region extending in the first direction, and the integrated circuit and the bonding region are connected by a conductive wire. Effect of the Invention

[0009] According to one aspect of the present invention, it is possible to provide a small-sized gas sensor that enables highly accurate measurement. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view illustrating an example of a gas sensor according to a first embodiment of the present invention. [Diagram 2] 1 is a plan view illustrating an example of a gas sensor according to a first embodiment of the present invention. [Diagram 3] 1A and 1B are a schematic plan view and a cross-sectional view illustrating an example of a gas sensor according to a first embodiment of the present invention. [Figure 4] 1A and 1B are a schematic back view and a cross-sectional view illustrating an example of a gas sensor according to a first embodiment of the present invention. [Diagram 5] 5A and 5B are a schematic view and a cross-sectional view showing an example of a gas sensor according to a second embodiment of the present invention, as viewed from a light reflecting portion side. [Figure 6] 11A and 11B are a schematic back view and a cross-sectional view showing a modified example of the gas sensor according to the second embodiment of the present invention. [Figure 7] FIG. 11 is a plan view illustrating an example of a gas sensor according to a third embodiment of the present invention. [Figure 8] FIG. 11 is a plan view illustrating an example of a gas sensor according to a fourth embodiment of the present invention. [Figure 9] FIG. 11 is a plan view illustrating an example of a gas sensor according to a fourth embodiment of the present invention. [Figure 10] 3 is a flowchart showing an example of a manufacturing process for the gas sensor according to the first embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are given the same or similar reference numerals. However, the drawings are schematic, and the relationship between thickness and planar dimensions is different from the actual one. In addition, the embodiments shown below are examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, shapes, structures, arrangements, etc. of the components as described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims described in the claims.

[0012] [First embodiment] 1 to 4 are schematic diagrams showing an example of a gas sensor according to a first embodiment of the present invention. Fig. 1 is a schematic diagram showing an example of a gas sensor according to the first embodiment, and is a schematic plan view seen from a mounting surface side to be connected to an external device. Here, the mounting surface side of the gas sensor 1 is referred to as the front surface, and the opposite surface is referred to as the back surface. Note that, for ease of understanding, connection wiring and a sealing member are omitted in Fig. 1.

[0013] 1, 1 denotes a gas sensor, 10 denotes a light receiving element, 20 denotes a light emitting element, 30 denotes an integrated circuit, 41 and 42 denote parts of a conductive lead frame 40, 41 denotes a die pad portion, and 42 denotes a terminal portion. The die pad portion 41 and the terminal portion 42 are spaced apart. In the die pad portion 41 and the terminal portion 42, R1 denotes a first region having a first thickness, and R2 denotes a second region having a second thickness thinner than the first thickness. The gas sensor 1 has a rectangular shape in a plan view, and a die pad portion 41 extending along the longitudinal direction is disposed in the center of the width direction of the gas sensor 1, and a plurality of terminal portions 42 are disposed in a line along the die pad portion 41 on both the left and right sides of the die pad portion 41.

[0014] The die pad portion 41 has a rectangular portion 41a extending along the longitudinal direction of the gas sensor 1 and protruding portions 41b formed at both longitudinal ends of the rectangular portion 41a. Two protruding portions 41b are formed at positions spaced apart from each other on the longitudinal ends of the rectangular portion 41a near the widthwise ends of the rectangular portion 41a, and the protruding portions 41b on both longitudinal ends are formed at positions equidistant from the widthwise center of the rectangular portion 41a, with the ends of the protruding portions 41b reaching the longitudinal ends of the gas sensor 1. A rectangular hole 41c (hereinafter referred to as a light receiving element arrangement region) for arranging the light receiving element 10 is formed at one longitudinal end side of the widthwise center of the rectangular portion 41a, and a rectangular hole 41d (hereinafter referred to as a light emitting element arrangement region) for arranging the light emitting element 20 is formed at the other longitudinal end side.

[0015] The terminal portions 42 are formed in the same shape as long, thin rectangles, and are arranged side by side at equal intervals along the long side of the rectangular portion 41a such that one end of each of the terminal portions 42 faces the long side of the rectangular portion 41a at a fixed interval, and the other end is formed to reach an end portion in the width direction of the gas sensor 1. In addition, the left and right terminal portions 42 sandwiching the die pad portion 41 are arranged to be linearly symmetrical with respect to the center of the gas sensor 1 in the longitudinal direction.

[0016] The rectangular portion 41a of the die pad portion 41 and a region of the protruding portion 41b that is adjacent to the rectangular portion 41a and that is about 1 / 3 of the entire protruding portion 41b form a second region 41(R2) having a second thickness. The region of the protruding portion 41b on the opposite side to the rectangular portion 41a, excluding the second region 41(R2), forms a first region 41(R1) having a first thickness. The region of each terminal 42 that is closer to the rectangular portion 41a and is slightly narrower than half of the entire terminal 42 forms a second region 42(R2) having a second thickness. The region of each terminal 42 on the opposite side to the rectangular portion 41a, excluding the second region 42(R2), that is slightly wider than half of the entire terminal 42 forms a first region 42(R1) having a first thickness.

[0017] The light receiving element 10 is arranged in the light receiving element arrangement region 41c, and the light emitting element 20 is arranged in the light emitting element arrangement region 41d. That is, the light receiving element 10 and the light emitting element 20 are arranged at positions surrounded by the second region 41(R2) of the die pad portion 41. The integrated circuit 30 is arranged in the width direction center, slightly closer to the light receiving element 10 than the longitudinal center of the rectangular portion 41a. That is, the integrated circuit 30 is arranged on the second region 41(R2) of the die pad portion 41. As shown in FIG. 3, which will be described later, a sealing member 80 is provided so as to encompass the entire lead frame 40, thereby packaging the lead frame 40 in a substantially rectangular parallelepiped shape. In addition, in FIG. 1, one integrated circuit 30 is arranged on the second region 41 (R2) of the die pad portion 41, but it is also possible to have multiple integrated circuits 30 and have the multiple integrated circuits 30 arranged on the second region 41 (R2) of the die pad portion 41.

[0018] Fig. 2 is a schematic plan view of the gas sensor 1 shown in Fig. 1, with electrical connections also shown. In the gas sensor 1, electrical connections are realized using conductive wires LW. As shown in FIG. 2, the light emitting element 20 has two terminals on each side along the longitudinal direction of the die pad portion 41. Each terminal of the light emitting element 20 is connected to a total of four terminal portions 42, two on each side, arranged on the end side of the light emitting element 20 side, among a plurality of terminal portions 42 arranged along the longitudinal direction of the die pad portion 41. Each terminal of the light emitting element 20 is connected only to the second region 42 (R2) of the terminal portion 42, and these are directly connected by a conductive wire LW. The light emitting element 20 is not directly connected to the light receiving element 10 or the integrated circuit 30. Here, "directly connected" means connected only by a single conductive wire LW.

[0019] 2, the light receiving element 10 has one terminal on the right end side of the end on the integrated circuit 30 side and one terminal on the left end side of the end opposite the integrated circuit 30. The light receiving element 10 is connected only to the integrated circuit 30, and each terminal of the light receiving element 10 is connected by conductive wires LW to two terminals provided on the end of the integrated circuit 30 on the light receiving element 10 side.

[0020] As shown in FIG. 2, the integrated circuit 30 has, for example, six terminals on each of the right and left ends of the integrated circuit 30, totaling 12 terminals, and two terminals on the light receiving element 10 side. The twelve terminals formed on the left and right sides of the integrated circuit 30 are connected to the remaining twelve terminals 42, excluding the terminals 42 connected to the light emitting element 20, among the multiple terminals 42 arranged on both sides of the die pad portion 41 along the longitudinal direction. Specifically, the terminals formed on the left and right ends of the integrated circuit 30 are connected to the second region 42 (R2) of the terminal portion 42 by the conductive wire LW. The second region 42 (R2) of the terminal portion 42 is a bonding region 42 (R3). The bonding region 42 (R3) is not particularly limited as long as it is thinner than the first region 42 (R1). From the viewpoint of ease of processing, it may be preferable that the bonding region 42 (R3) has the same thickness as the second region 41 (R2) of the die pad portion 41 as shown in FIG. 2. The surface of the bonding region 42(R3) (that is, the second region 42(R2)) may be plated.

[0021] Fig. 3 is a diagram in which a sealing member 80 is added to the gas sensor 1 shown in Fig. 2, and Fig. 3(a) is a schematic plan view of the gas sensor 1. Fig. 3(b) is a schematic cross-sectional view taken along line AA' in Fig. 3(a), Fig. 3(c) is a schematic cross-sectional view taken along line BB' in Fig. 3(a), and Fig. 3(d) is a schematic cross-sectional view taken along line CC' in Fig. 3(a). As shown in FIG. 3, the sealing member 80 covers the light receiving element 10, the light emitting element 20, the integrated circuit 30, the conductive wire LW, and the second regions 41 (R2) and 42 (R2) of the lead frame 40, except for the first regions 41 (R1) and 42 (R1) of the lead frame 40, and is formed so as to be flush with the surfaces of the first regions 41 (R1) and 42 (R1) of the lead frame 40.

[0022] As a result, in the schematic plan view shown in FIG. 3(a), it can be understood that the surface of the gas sensor 1 in plan view, that is, the surface that is the upper side in the schematic cross-sectional views shown in FIGS. 3(b) to (d), is in a state in which only the sealing member 80, the first region 41(R1) (not shown) of the die pad portion 41, and the first region (R1) of the terminal portion 42 are exposed.

[0023] Fig. 4 is a schematic back view (Fig. 4(a)) of the gas sensor 1 shown in Fig. 3, seen from the back side, that is, from the side where each of the light receiving element 10 and the light emitting element 20 is partially exposed. Fig. 4(b) is a schematic cross-sectional view in plane AA' in Fig. 4(a), and Fig. 4(c) is a schematic cross-sectional view in plane BB' in Fig. 4(a). For simplification, the conductive wire LW is omitted from the illustration. It can be understood that the back surface of the gas sensor 1 shown in FIG. 4(a), i.e., the upper surface in the schematic cross-sectional views shown in FIGS. 4(b) and 4(c), exposes the back surface of the die pad portion 41, the back surface of the terminal portion 42, the back surface of the light receiving element 10, the back surface of the light emitting element 20, and the sealing member 80.

[0024] As shown in FIG. 4, a die pad portion 41 is exposed between the light receiving element 10 and the light emitting element 20 on the back surface of the gas sensor 1. By forming the die pad portion 41 from a conductive material with high reflectivity, it may be preferable in a configuration having an optical path as shown in the second embodiment described later, since infrared rays emitted from the light emitting element 20 can reach the light receiving element 10 more efficiently.

[0025] In addition, when the gas sensor 1 is viewed from above as shown in FIG. 3, the light receiving element 10 and the light emitting element 20 are surrounded by the second region 41(R2) of the die pad portion 41, and the integrated circuit 30 is disposed on the second region 41(R2) of the die pad portion 41. Therefore, by forming the die pad portion 41, i.e., the lead frame 40, from a material with high thermal conductivity, the temperature inside the package is made uniform. This enables more accurate compensation of temperature characteristics, and more accurate concentration measurement. When the gas sensor 1 is configured to measure the temperature inside the package using the diode characteristics inside the integrated circuit 30, the effect of making the temperature inside the package uniform is more effectively achieved.

[0026] The integrated circuit 30 is not particularly limited as long as it is electrically connected to at least one of the light receiving element 10 and the terminal portion 42. The integrated circuit 30 preferably includes at least one, and preferably all of the following: (1) a circuit that stores calibration parameters of each part requiring calibration, such as the light receiving element 10 and the light emitting element 20, and is capable of outputting the calibration parameters, (2) a circuit that amplifies a signal from the light receiving element 10 and performs AD conversion, (3) a circuit that outputs a drive signal that drives the light emitting element 20, (4) a circuit that performs intermittent drive control of the light receiving element 10 and the light emitting element 20, and (5) an interface circuit with an external device (e.g., a signal processing circuit).

[0027] In the gas sensor 1 configured in this manner, the light-emitting element 20 is driven in a space in which the gas to be measured is present, and the light irradiated from the light-emitting element 20 is received by the light-receiving element 10. The integrated circuit 30 performs calibration of parameter signals of the light-receiving element 10 and the light-emitting element 20 based on the received signal, and then outputs the result as a sensor signal to an external device, and the external device performs calculations of the concentration of the gas to be measured based on the sensor signal.

[0028] [Effects of the first embodiment] The gas sensor 1 according to the first embodiment has the configuration shown in Fig. 1 to Fig. 4. Therefore, the die pad portion 41 with good thermal conductivity can equalize the temperatures of the light receiving element 10, the light emitting element 20, and the integrated circuit 30 in the package. As a result, by calibrating a parameter signal corresponding to at least one characteristic of each portion, such as the light receiving element 10, the light emitting element 20, etc., based on the temperature of the integrated circuit 30, it is possible to compensate for the temperature characteristics with higher accuracy, and as a result, it is possible to perform concentration measurement with higher accuracy. In addition, the die pad portion 41 has a first region 42 (R1) having a first thickness and a second region 41 (R2) having a second thickness thinner than the first thickness, and the integrated circuit 30 is placed on the thinner second region 41 (R2), thereby enabling high-precision measurements while still achieving miniaturization.

[0029] In addition, by performing calibration based on the temperature of the integrated circuit 30 in the package, it is possible to compensate for temperature characteristics, and by incorporating an external integrated circuit in the same package, the entire gas sensor 1 can be made smaller. Furthermore, since the light-emitting element 20 is not directly electrically connected to the light-receiving element 10 and the integrated circuit 30, there is a high degree of freedom in layout, which enables high-precision compensation of temperature characteristics due to layout and the realization of a smaller gas sensor 1.

[0030] [Second embodiment] Next, a second embodiment of the present invention will be described. FIG. 5 is a schematic diagram of a gas sensor 1a according to a second embodiment, in which a light reflecting portion 60 having a dome-shaped space portion 60a on the inside is further provided on the back side of the gas sensor 1 shown in FIG. The light reflecting portion 60 has a rectangular parallelepiped shape in a plan view, and is formed with a width that covers the second region 42(R2) of each terminal portion 42 and a part of the second region 42(R2) side of the first region 42(R1), and is formed with a length that covers the entire first region 41(R1) of the die pad portion 41. The light reflecting portion 60 has an ellipsoid surface facing the light receiving surface of the light receiving element 10 and the light emitting surface of the light emitting element 20, and has a dome-shaped reflecting surface 60b on the inside, and the space portion 60a is formed to a size that the light receiving element 10 and the light emitting element 20 can fit within the space portion 60a when viewed from the back side. The material of the portion that becomes the reflecting surface 60b of the light reflecting portion 60 is preferably a metal or a multilayer dielectric film. In this embodiment, one integrated circuit 30 is arranged on the second region 41 (R2) of the die pad portion 41, but it is also possible to have multiple integrated circuits 30 and arrange the multiple integrated circuits 30 on the second region 41 (R2) of the die pad portion 41.

[0031] Furthermore, the light reflecting portion 60 may have any overall shape as long as it has a dome-shaped reflecting surface 60b. Further, the light reflecting portion 60 is formed with a vent hole (not shown) penetrating the light reflecting portion 60, through which the gas to be measured is introduced into the space portion 60a and is discharged to the outside of the space portion 60a. In the gas sensor 1a, the integrated circuit 30 performs a predetermined process based on a detection signal from the light receiving element 10 when the gas to be measured is introduced into the space portion 60a, and outputs a signal corresponding to the detection signal, and an external device (not shown) electrically connected to the integrated circuit 30 performs concentration calculations and the like based on the detection signal input from the integrated circuit 30.

[0032] In this way, in the second embodiment, the light reflecting portion 60 having the dome-shaped reflecting surface 60b on the inside is provided. As a result, it may be preferable because it is possible to easily guide the infrared ray emitted from the light emitting element 20 to the light receiving element 10. In addition, by forming the die pad portion 41 from a conductive material with high reflectivity, the infrared ray emitted from the light emitting element 20 can reach the light receiving element 10 more efficiently.

[0033] [Modification of the second embodiment] Fig. 6 is a schematic diagram showing a modified example of the gas sensor 1a according to the second embodiment, which further includes an optical member 70 and a mounting substrate 100 in addition to the gas sensor 1a including the light reflecting portion 60 shown in Fig. 5. Fig. 6(a) is a schematic diagram showing the gas sensor 1b in the modified example, as viewed from the side opposite to the light reflecting portion 60, i.e., the back surface side, Fig. 6(b) is a schematic cross-sectional view taken along the DD' plane in Fig. 6(a), and Fig. 6(c) is a schematic cross-sectional view taken along the EE' plane in Fig. 6(a).

[0034] The optical member 70 is made of a filter block in which the side of an optical filter (not shown) is covered with a sealing portion. The optical filter has a function of selectively transmitting light in a desired wavelength range (i.e., with high transmittance). Materials that transmit light in a preset wavelength range, such as silicon (Si) and glass (SiO2), are used as materials for the optical member that constitutes the optical filter. The optical filter is not limited to this, and may be configured such that a thin film is provided on the optical member by deposition or the like, or may be a dielectric multilayer filter in which dielectrics having different refractive indices are layered on the optical member.

[0035] As shown in Figure 6(a), the optical member 70 is formed in an approximately square shape when viewed from the back surface side, one side of the optical member 70 has a length equal to both ends of the two convex portions 41b of the die pad portion 41, and the optical member 70 is arranged so that one side of the optical member 70 overlaps with the boundary between the first region 41 (R1) and the second region 41 (R2) of the convex portion 41b provided at the end of the die pad portion 41 on the light-emitting element 20 side when viewed from the back surface side, and further overlaps on the light-emitting element 20. As shown in FIG. 6, the inclusion of an optical member 70 may be preferable since it can easily realize emission and / or reception of infrared rays of a specific wavelength.

[0036] Although FIG. 6 shows an example in which the optical member 70 is disposed on the light-emitting element 20 side, it may be disposed on the light-receiving element 10 side. The optical member 70 may directly cover the surfaces of the light-emitting element 20 and the light-receiving element 10, or may indirectly cover them with another substance or space therebetween. In other words, the optical member 70 may be disposed in the optical path from the light emitted from the light-emitting element 20 to the light-receiving element 10. The mounting substrate 100 is larger than the package integrated by the sealing member 80, and has mounting terminals 110 at positions facing the first regions 42(R1) of the terminal portions 42. FIG. 6 shows a case where eight mounting terminals 110 are provided on one side, for a total of 16 mounting terminals 110 on both sides. The mounting terminals 110 are electrically connected to the first regions 42(R1) of the terminal portions 42 via metal bumps 200 (FIG. 6(c)). Although not shown, it is preferable that the light-emitting element 20 is electrically connected to the integrated circuit 30 via the mounting substrate 100 by electrically connecting the mounting substrate 100 and the terminal portions 42 via the metal bumps 200.

[0037] [Third embodiment] Next, a third embodiment of the present invention will be described. Fig. 7 is a schematic plan view showing an example of a gas sensor 1c according to the third embodiment, in which the conductive wire LW and the sealing member 80 are omitted. The gas sensor 1c according to the third embodiment is different from the gas sensor 1 according to the first embodiment shown in Fig. 1 in the shape of the first region and the second region of the die pad portion 41. Specifically, in the gas sensor 1 shown in Fig. 1, the boundary line BL between the first region 41(R1) and the second region 41(R2) of the die pad portion 41 is a single straight line in a plan view, whereas in Fig. 7, the boundary line BL between the first region 41ba(R1) and the second region 41aa(R2) of the die pad portion 41 is not a single straight line but is composed of three line segments. That is, the die pad portion 41 includes a rectangular portion 41a and a protruding portion 41b, and the first region 41ba(R1) of the die pad portion 41 is composed of the protruding portion 41b and a part of the rectangular portion 41a that is continuous with the protruding portion 41b, and forms a region having a first thickness that is rectangular in shape in a plan view to which the protruding portion 41b is extended. In other words, as shown in FIG. 7, in the die pad portion 41, the boundary between a first region 41ba (R1) having a first thickness and a second region 41aa (R2) having a second thickness thinner than the first thickness is formed by three line segments along three sides of the end portion of the first region 41ba (R1) on the second region 41aa (R2) side, and the three sides of the end portion of the first region 41ba (R1) are surrounded by the second region 41aa (R2).

[0038] This improves the shape stability of the second region 41aa (R2) of the die pad portion 41 and the positional stability during processing, making it easier to position the light receiving element 10 and the light emitting element 20 in the designed position, which can contribute to improving measurement accuracy. It is sufficient that at least one of the four protruding parts 41b of the die pad part 41 is a first region 41ba (R1) in which the protruding part 41b and a part of the rectangular part 41a have a first thickness, and the boundary line BL between the first region 41ba (R1) and the second region 41aa (R2) is formed by a plurality of straight lines, but it is preferable that each of the four protruding parts 41b of the die pad part 41 and a part of the rectangular part 41a is a first region 41ba (R1), and each of the boundary lines BL with the second region 41aa (R2) is formed by a plurality of straight lines rather than a single straight line. Also, the boundary line BL does not necessarily have to be a straight line, and it is sufficient that the second region 41aa (R2) is formed so as to surround the periphery of the end of the first region 41ba (R1). In this embodiment, one integrated circuit 30 is arranged on the second region 41 (R2) of the die pad portion 41, but it is also possible to have multiple integrated circuits 30 and arrange the multiple integrated circuits 30 on the second region 41 (R2) of the die pad portion 41.

[0039] From the viewpoint of enhancing the contribution to the improvement of the measurement accuracy, it is preferable that, as in the gas sensor 1c shown in FIG. 7, a part of a line segment of the smallest convex polygon CP among the convex polygons including the entire second region 41aa (R2) of the die pad portion 41 in a plan view intersects with the first region 41ba (R1) of the die pad portion 41. This further improves the stability of the second region 41aa (R2) of the die pad portion 41, and as a result, the measurement accuracy is further improved. Furthermore, as shown in FIG. 6 in the second embodiment, when the gas sensor 1c is mounted on the mounting substrate 100, it is preferable that the first region 41ba (R1) is electrically connected to the mounting substrate 100 as a terminal portion. The metal bump 200 with good thermal conductivity makes it possible to make the temperature of the die pad portion 41 more uniform.

[0040] [Fourth embodiment] Next, a fourth embodiment of the present invention will be described. Fig. 8 is a schematic plan view showing an example of a gas sensor 1d according to the fourth embodiment, in which the sealing member is omitted. The gas sensor 1d according to the fourth embodiment is different from the gas sensor 1 according to the first embodiment shown in Fig. 2 in that the shape of one terminal portion 42L among the multiple terminal portions 42 is different. Also, the shape of the rectangular portion 41aL of the die pad portion 41 is different so as to match the shape of the terminal portion 42L. Specifically, as shown in FIG. 8, when the gas sensor 1d is placed so that the end on the light-emitting element 20 side is on the top and the end on the light-receiving element 10 side is on the bottom in a plan view, a rectangular portion 41aL of the die pad portion 41 is formed, the rectangular portion 41aL is located between the light-emitting element 20 and the integrated circuit 30, and a cutout portion 41aL1 is formed on the right end side of a position slightly closer to the light-emitting element 20 than the longitudinal center of the rectangular portion 41aL, and a first region 41aL(R1) having a first thickness is formed on the left end side.

[0041] In this embodiment, one integrated circuit 30 is disposed on the second region 41 (R2) of the die pad portion 41, but a plurality of integrated circuits 30 may be provided and disposed on the second region 41 (R2) of the die pad portion 41. In this case, it is preferable from the viewpoint of durability to have a first region 41 (R1) having a first thickness in at least a portion between the plurality of integrated circuits 30 in a plan view. In this embodiment, a second region 41(R2) having a second thickness may be provided in a first region 41aL(R1) having a first thickness, and an integrated circuit 30 may be further disposed in this second region 41(R2).

[0042] Furthermore, among the eight terminal portions 42 arranged on the right end side of the gas sensor 1d, the shape of the third terminal portion 42L from the end on the light-emitting element 20 side, which faces the cutout portion 41aL1, is different from the shape of the third terminal portion 42LL from the end on the light-emitting element 20 side, which faces the first region 41aL(R1) of the die pad portion 41aL, of the eight terminal portions 42 arranged on the left end side of the gas sensor 1d.

[0043] As shown in FIG. 8, the terminal portion 42L includes a region 42L(D2) extending in a second direction (D2) that is a direction of the terminal portion 42 toward the die pad portion 41aL in a plan view, and a region 42L(D1) extending in a first direction (D1) perpendicular to the second direction (D2), and has a shape bent in the shape of the letter "L". Note that the first direction (D1) is not necessarily perpendicular to the second direction (D2), and may be a shape in which two directions intersect and bent obliquely. That is, it is sufficient that the second region 42L(R2)b described later can be disposed near the integrated circuit 30. Here, the intersection means that two or more line segments intersect at one point, and does not only mean a shape in which they intersect perpendicularly.

[0044] Similarly to the terminal 42, the terminal 42L has a first region 42L(R1)a having a first thickness and a second region 42L(R2)a having a second thickness from the right end side of the gas sensor 1d. The terminal 42L further includes a first region 42L(R1)b having a first thickness and continuous with the second region 42L(R2)a, and a second region 42L(R2)b having a second thickness and continuous with the first region 42L(R1)b. The first region 42L(R1)b includes a region extending to an end in the second direction continuous with the second region 42L(R2)a, and a region that is continuous with the region extending to the end in the second direction and is about 1 / 8 of the entire region extending in the first direction. The second region 42L(R2)b includes the region extending in the first direction excluding the first region 42L(R1)b. The second region 42L(R2)b having the second thickness forms the bonding region 42L(R3).

[0045] On the other hand, the terminal portion 42LL has a shape in which the second region 42(R2) is extended in the terminal portion 42, and is provided with a first region 42LL(R1) and a second region 42LL(R2) having a second thickness that is continuous with the first region 42LL(R1), and the end of the second region 42LL(R2) opposite the first region 42(R1) is continuous with the first region 41aL(R1) of a first thickness formed in the rectangular portion 41aL.

[0046] 8, the layout of electrical connections via the conductive wire LW becomes easier, and this may be preferable since it may enable the overall size to be reduced. That is, as shown in FIG. 8, the end of the terminal portion 42L on the die pad portion 41 side extends to the vicinity of the center in the width direction of the die pad portion 41. Therefore, if a terminal is provided at the end of the integrated circuit 30 on the light receiving element 10 side and this terminal is connected to the second region 42L(R2)b of the terminal portion 42L, which is the bonding region 42L(R3), with the conductive wire LW, the length of the conductive wire LW can be short, and the wiring can be easily laid out. In addition, a first region 41aL(R1) is provided on the opposite side of the rectangular portion 41aL to the cutout portion 41aL1, and this first region 41aL(R1) is thicker than the second region 41(R2). Therefore, it is possible to suppress a decrease in stability of the rectangular portion 41aL caused by providing the cutout portion 41aL1.

[0047] In addition, in the terminal portion 42L, it is preferable that the region extending in the second direction has a region with a different thickness. Specifically, as shown in FIG. 8, it is preferable that a part of the region extending in the second direction is a second region 42L(R2)a having a thickness thinner than that of the first region. This makes it possible to smooth the flow of the sealing resin when molding the lead frame 40, the light receiving element 10, the light emitting element 20, and the integrated circuit 30 with the sealing member 80, thereby suppressing the positional deviation of the light receiving element 10 and the light emitting element 20 and suppressing the deterioration of the measurement accuracy. Note that the second region 42L(R2)a is provided for the purpose of smoothing the flow of the sealing resin, and therefore does not necessarily have to have the second thickness, but only needs to be thinner than the first thickness. From the viewpoint of smoothing the flow of the sealing resin, it is preferable to make the film thickness equal to that of the second region 42(R2) of the other terminal portion 42.

[0048] [Modification of the fourth embodiment] Fig. 9 is a schematic plan view showing an example of a gas sensor 1e according to the fourth embodiment. In the gas sensor 1e, two adjacent terminals 42L1 and 42L2 facing the notch 41aL1 in the gas sensor 1d shown in Fig. 8 have regions 42L1(D2) and 42L2(D2) extending in the second direction (D2), respectively, and further, both ends of the regions 42L1(D2) and 42L2(D2) are connected to a region 42L12(D1) extending in the first direction (D1).

[0049] Similarly to the terminal portion 42, the terminal portion 42L1 includes, from the right end side of the gas sensor 1e, a first region 42L1(R1)a having a first thickness, a second region 42L1(R2)a having a second thickness, and a first region 42L1(R1)b and a second region 42L1(R2)b having a second thickness. Similarly to the terminal portion 42, the terminal portion 42L2 includes, from the right end side of the gas sensor 1e, a first region 42L2(R1)a having a first thickness, a second region 42L2(R2)a having a second thickness, and a first region 42L2(R1)b and a second region 42L2(R2)b having a second thickness.

[0050] The region 42L12(D1) includes a first region 42L12(R1) having a first thickness, and a second region 42L12(R2) having a second thickness that is continuous with the first region 42L12(R1). By forming the two terminals 42L1 and 42L2 facing the cutout 41aL1 in the shape shown in Fig. 9, shape stability can be improved, which may be preferable. In Fig. 9, the regions 42L1(D2) and 42L2(D2) extending in the second direction each have two second regions (42L1(R2)a, 42L1(R2)b, 42L2(R2)a, 42L2(R2)b) thinner than the first region R1. This may be preferable because it has the effect of opening the dead end between the two regions 42L1(D2) and 42L2(D2) extending in the second direction to smooth the flow of the sealing resin.

[0051] [Manufacturing method] Next, an example of a method for manufacturing the gas sensor 1 according to this embodiment will be described. Here, the method for manufacturing the gas sensor 1 according to the first embodiment will be described with reference to Fig. 10. Fig. 10 is a schematic cross-sectional view taken along the FF' plane in Fig. 1. First, a lead frame 40 is placed on a heat-resistant tape 201, which has been patterned and half-etched to form a die pad portion 41 having a first region 41 (R1) with a first thickness and a second region 41 (R2) thinner than the first region 41 (R1), and a terminal portion 42 (FIG. 10(a)). To facilitate wire bonding, which will be described later, the surface of the lead frame 40 may be plated.

[0052] Next, the light receiving element 10 and the light emitting element 20 are arranged in the area (light receiving element arrangement area 41c, light emitting element arrangement area 41d) surrounded by the second area 41 (R2) of the die pad part 41 on the heat resistant tape 201 via the adhesive layer of the heat resistant tape 201, and the integrated circuit 30 is arranged in the second area 41 (R2) of the die pad part 41, preferably via an adhesive or film with high thermal conductivity, and the light receiving element 10 and the integrated circuit 30, the light emitting element 20 and the second area 42 (R2) of each terminal part 42, and the integrated circuit 30 and the second area 42 (R2) of each terminal part 42 are wire bonded with conductive wires LW, respectively (FIG. 10(b)). For simplification, FIG. 10(b) shows one conductive wire LW connecting the light receiving element 10 and the integrated circuit 30, and one conductive wire LW connecting the light emitting element 20 and the second area 42 (R2) of the terminal part 42).

[0053] Next, a lower mold 203 is placed on the side where the heat-resistant tape 201 is placed, and an upper mold 202 is placed on the side opposite to the side where the heat-resistant tape 201 is placed, and a sealing resin that will become the sealing member 80 is injected into the space sandwiched between the heat-resistant tape 201 and the upper mold 202 (Figure 10(c)). Next, the upper mold 202 and the lower mold 203 are removed, and the heat-resistant tape 201 is also removed. The region of the kerf width W is then diced by a dicing device into individual pieces and then inverted to obtain the gas sensor 1 with the light-receiving element 10 and a part of the light-emitting element 20 exposed on the upper surface side (FIG. 10(d)).

[0054] Although the embodiments of the present invention have been described above, the above embodiments are merely examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the material, shape, structure, arrangement, etc. of the components. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims. [Explanation of symbols]

[0055] 1, 1a to 1e Gas sensors 10 Photodetector 20 Light emitting element 30 Integrated Circuits 40 Lead Frame 41 Die pad section 41a, 41aL rectangular part 41aL1 Notch 41b Convex part 41(R1), 41ba(R1), 41aL(R1) First area of ​​die pad 41(R2), 41aa(R2) Second area of ​​die pad 42, 42L, 42L1, 42L2, 42LL terminal section 42(R1), 42L1(R1) First area of ​​terminal 42(R2), 42L2(R2), second area of ​​terminal 60 Light reflection part 60a Space 60b reflective surface 70 Optical Components 80 Sealing member 100 Mounting Board 110 Mounting terminal 200 Metal Bump BL boundary line LW Conductive Wire

Claims

1. A gas sensor including a light receiving element, a light emitting element, an integrated circuit, a lead frame, and a sealing member for packaging these elements, the lead frame has at least one die pad portion and a plurality of terminal portions, at least the die pad portion having a first region having a first thickness and a second region having a second thickness thinner than the first thickness; the integrated circuit is disposed on the second region of the die pad portion and is electrically connected to at least one of the plurality of terminal portions; A gas sensor in which the first region of the die pad portion is disposed around the second region, and the second region is disposed so as to surround a part of an end portion of the first region.

2. the light emitting element is electrically connected to at least one of the plurality of terminal portions, 2. The gas sensor according to claim 1, wherein the light receiving element is electrically connected to the integrated circuit and is disposed on an opposite side of the integrated circuit from the light emitting element.

3. 3. The gas sensor according to claim 2, wherein the light emitting element is not directly electrically connected to the light receiving element and the integrated circuit.

4. 4. The gas sensor according to claim 3, wherein the light receiving element is electrically connected to the integrated circuit via a conductive wire.

5. the light emitting element and the integrated circuit are mounted on a mounting substrate; 5. The gas sensor according to claim 3, wherein the light emitting element is electrically connected to the integrated circuit via the mounting substrate.

6. 6 . The gas sensor according to claim 1 , wherein the first regions of the die pad portion are arranged such that the second region surrounds a part of an end of the first region.

7. 7. The gas sensor according to claim 6, wherein a part of a line segment of a smallest convex polygon that includes the entire second region of the die pad portion intersects with the first region of the die pad portion in a plan view.

8. A gas sensor including a light receiving element, a light emitting element, an integrated circuit, a lead frame, and a sealing member for packaging these elements, the lead frame has at least one die pad portion and a plurality of terminal portions, at least the die pad portion having a first region having a first thickness and a second region having a second thickness thinner than the first thickness; the integrated circuit is disposed on the second region of the die pad portion and is electrically connected to at least one of the plurality of terminal portions; Furthermore, the plurality of terminal portions are arranged side by side along the die pad portion on both sides of the die pad portion, At least one of the plurality of terminals electrically connected to the integrated circuit has a region extending in a second direction intersecting a direction in which the plurality of terminals are arranged between the integrated circuit and the light-emitting element, and a region extending in a first direction intersecting the second direction and approaching the integrated circuit, and has a bonding region at a tip of the region extending in the first direction; The gas sensor includes a conductive wire connecting the integrated circuit and the bonding region.

9. Each of the plurality of terminal portions electrically connected to the integrated circuit among the plurality of terminal portions has a region extending in the second direction, 9. The gas sensor according to claim 8, wherein the region extending in the second direction of each of the plurality of terminals is connected to a common region extending in the first direction.

10. 10. The gas sensor according to claim 8, wherein the region extending in the second direction has a region with a different thickness therein.

11. The terminal portion has the first region and the second region, 11. The gas sensor according to claim 1, further comprising a first surface from which only a portion of each of the plurality of terminal portions, a portion of the die pad portion, and a portion of the sealing member are exposed.

12. The terminal portion has the first region and the second region, 12. The gas sensor according to claim 1, further comprising a second surface from which only a portion of each of the plurality of terminal portions, a portion of the die pad portion, a portion of the light receiving element, a portion of the light emitting element, and a portion of the sealing member are exposed.

13. The gas sensor according to claim 12 , further comprising a light reflecting portion including a space therein that covers at least a portion of the second surface.

14. 14. The gas sensor according to claim 12, further comprising an optical member that transmits light of a desired wavelength and is arranged so as to directly or indirectly cover an exposed portion of at least one of the partially exposed light-emitting element and the partially exposed light-receiving element.

15. 15. The gas sensor according to claim 1, wherein the integrated circuit is electrically connected to at least one of the plurality of terminal portions via a conductive wire.

16. 16. The gas sensor according to claim 15, wherein the terminal portion to which the conductive wire is connected has a bonding region, and a thickness of the bonding region is smaller than the first thickness.

17. 17. The gas sensor of claim 16, wherein the bonding area has a plating on a surface thereof, and the conductive wire is directly connected to the plating.

18. 18. The gas sensor according to claim 1, wherein the integrated circuit outputs a control signal for controlling the light emitting element, and receives a signal from the light receiving element, amplifies the signal, and performs AD conversion.

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