JP7618466B2 - Semiconductor Device - Google Patents

Description

The present invention relates to a semiconductor device.

The semiconductor device described in Patent Document 1 below has been known for some time. In this semiconductor device, a semiconductor element arranged on the surface of a wiring board, an element mounting portion, a portion of the lead wires, a portion of the hanging pin portion, a die attachment material, and a bonding wire are resin-sealed with a resin sealant made of epoxy resin or the like.

JP 2007-42702 A

Incidentally, when mounting a semiconductor light-emitting element (LED light source) on a substrate and sealing the semiconductor light-emitting element with resin, it is common to use a transparent resin so as not to impede the light emission of the semiconductor light-emitting element. However, it is difficult to add substances to the transparent resin, for example, substances that mitigate the thermal expansion difference with the substrate, in order to ensure the translucency of the transparent resin. If a thermal expansion difference occurs between the transparent resin and the substrate, and shear stress is applied to the connection interface between the semiconductor light-emitting element and the land of the substrate, the thermal stress may cause the semiconductor light-emitting element to peel off from the land.

The present invention was made in consideration of the above problems, and aims to provide a semiconductor device that reduces the stress of the transparent resin applied to the semiconductor light-emitting element and prevents the semiconductor light-emitting element from peeling off from the land.

A semiconductor device according to one aspect of the present invention includes a substrate having a land, a semiconductor light-emitting element attached to the land, a transparent resin covering the semiconductor light-emitting element, and a protrusion that protrudes from the periphery of the land higher than the upper end of the semiconductor light-emitting element and contacts the transparent resin.

In the semiconductor device, the protrusions may be provided in pairs, sandwiching the land.

In the semiconductor device, the protrusion may extend linearly along the land in a plan view.

In the semiconductor device, the protrusions may be provided in a spot shape along the land in a plan view.

In the above semiconductor device, the substrate may have a first plane and a second plane recessed relative to the first plane, and the land may be provided on the second plane.

In the above semiconductor device, the land may have an outer shape smaller than a fillet of conductive adhesive that connects the semiconductor light-emitting element to the land.

According to one aspect of the present invention, it is possible to provide a semiconductor device that can reduce the stress of the transparent resin applied to the semiconductor light-emitting element and prevent the semiconductor light-emitting element from peeling off from the land.

1 is a plan view showing a semiconductor device according to a first embodiment of the present invention; 2 is a cross-sectional view taken along line II-II of FIG. 1. FIG. 11 is a plan view showing a modified example of the protrusion according to the first embodiment of the present invention. FIG. 11 is a plan view showing a modified example of the protrusion according to the first embodiment of the present invention. 11 is a cross-sectional view showing a main part of a semiconductor device according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view showing a main part of a semiconductor device according to a third embodiment of the present invention. 1 is a cross-sectional view showing a modified example of a main part of the semiconductor device according to the first embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings.

First Embodiment
1 is a plan view showing a semiconductor device 1 according to a first embodiment of the present invention, and FIG 2 is a cross-sectional view taken along line II-II of FIG 1.
1 is a reflective optical encoder. The semiconductor device 1 includes a housing 2 having a rectangular shape in a plan view, a light projecting unit 3 and a light receiving unit 4 housed in the housing 2, and a partition wall 5 that separates the light projecting unit 3 and the light receiving unit 4 within the housing 2.

The partition 5 is provided on a substrate 6 housed in the housing 2, and the light-projecting unit 3 and the light-receiving unit 4 are mounted on one substrate 6, separated by the partition 5. Note that the light-projecting unit 3 and the light-receiving unit 4 may be mounted on two separate substrates.

The light receiving unit 4 includes a semiconductor light receiving element 10. The semiconductor light receiving element 10 is, for example, a CMOS amplifier IC equipped with a light sensor. A plurality of connection electrodes are provided on the surface of the semiconductor light receiving element 10, and are electrically connected to a plurality of bonding pads 11 provided on the substrate 6 via bonding wires 12.

The light projecting unit 3 is equipped with a semiconductor light emitting element 20. The semiconductor light emitting element 20 is, for example, an LED light source. A connection electrode is provided on the surface of the semiconductor light emitting element 20, and is electrically connected to a plurality of bonding pads 21 provided on the substrate 6 via bonding wires 22.

A connection electrode is provided on the back surface of the semiconductor light-emitting element 20 by Au deposition or the like, and is electrically connected to a land 23 provided on the substrate 6 via a conductive adhesive 24. The conductive adhesive 24 is, for example, an Ag paste adhesive (main component is epoxy resin). Note that instead of the conductive adhesive 24, the semiconductor light-emitting element 20 may be connected to the land 23 by soldering.

As shown in the cross-sectional view of FIG. 2, the semiconductor light-emitting element 20 is covered with a transparent resin 40. The transparent resin 40 seals the semiconductor light-emitting element 20, the land 23, the conductive adhesive 24, the surface 7 of the substrate 6, and the protrusions 30 described below. This transparent resin 40 has a higher thermal expansion coefficient than the substrate 6 (e.g., a glass epoxy substrate), and is, for example, a transparent epoxy resin or silicone resin.

A protrusion 30 (dam) is erected around the periphery of the land 23. The protrusion 30 protrudes from the surface 7 of the substrate 6 to a position higher than the upper end 20a of the semiconductor light-emitting element 20. Note that the "upper end 20a of the semiconductor light-emitting element 20" referred to here is the chip surface (top surface) of the semiconductor light-emitting element 20, but it may also be the upper end of a connection electrode (not shown) protruding from the chip surface.

The transparent resin 40 is molded up to a position higher than the upper end 30a of the protrusion 30. The transparent resin 40 is in contact with the upper end 30a and the side 30b of the protrusion 30. The side 30b of the protrusion 30 faces the connection interface 25 between the back surface 20b (Au vapor deposition surface) of the semiconductor light emitting element 20 and the land 23 by the conductive adhesive 24, and the side 20c of the semiconductor light emitting element 20, across the transparent resin 40, in the plate surface direction along the surface 7 of the substrate 6.

As shown in FIG. 1, the protrusions 30 are provided in pairs, sandwiching the land 23. In addition, the protrusions 30 extend linearly and parallel to the land 23 in a plan view. The longitudinal dimension of the protrusions 30 is longer than the land 23. The protrusions 30 can be formed by, for example, attaching a plate-shaped member that is rectangular in a plan view to the substrate 6.

As shown in FIG. 2, in the semiconductor device 1 having the above configuration, the protrusions 30 protruding from the periphery of the land 23 higher than the upper end 20a of the semiconductor light-emitting element 20 suppress the movement of the transparent resin 40 that tends to spread along the plate surface direction of the substrate 6 due to the difference in thermal expansion with the substrate 6, thereby mitigating the thermal stress applied to the side surface 20c of the semiconductor light-emitting element 20. This reduces the shear stress applied to the connection interface 25 between the semiconductor light-emitting element 20 and the land 23 by the conductive adhesive 24, and suppresses the semiconductor light-emitting element 20 from peeling off from the land 23.

In particular, epoxy, the main component of Ag paste, as in the conductive adhesive 24 of this embodiment, bonds by combining its own -OH group (hydroxy group) with the -O group (carbonyl group) on the surface to be bonded, but when Au is vapor-deposited, as in the case of the back surface 20b of the semiconductor light-emitting element 20 of this embodiment, the back surface 20b does not oxidize, so it is assumed that the Ag paste does not bond it, but rather that the adhesive strength of the main component epoxy is the only factor that holds it in place. This configuration is particularly effective under conditions in which such semiconductor light-emitting element 20 is prone to peeling off from the land 23.

As described above, the semiconductor device 1 of the first embodiment includes a substrate 6 having lands 23, a semiconductor light-emitting element 20 attached to the lands 23, a transparent resin 40 covering the semiconductor light-emitting element 20, and a protrusion 30 that protrudes from the periphery of the land 23 higher than the upper end 20a of the semiconductor light-emitting element 20 and contacts the transparent resin 40. This configuration reduces the stress of the transparent resin 40 applied to the semiconductor light-emitting element 20, and prevents the semiconductor light-emitting element 20 from peeling off from the land 23.

In addition, in the first embodiment, the protrusions 30 are provided in pairs, sandwiching the land 23. With this configuration, the stress of the transparent resin 40 applied to the side surface 20c of the semiconductor light emitting element 20 can be alleviated from either the left or right.

In the first embodiment, the protrusion 30 extends linearly along the land 23 in the plan view shown in FIG. 1. With this configuration, the protrusion 30 can be formed by, for example, attaching a plate-shaped member to the substrate 6.

In the first embodiment described above, the following modifications can be made:

FIG. 3 is a plan view showing a modified example of the protrusion 30 according to the first embodiment of the present invention.
3 are provided in spots along the lands 23 in a plan view. With this configuration, the protrusions 30 can be formed by potting a liquid resin onto the substrate 6 or the like.

FIG. 4 is a plan view showing a modified example of the protrusion 30 according to the first embodiment of the present invention.
4 is integral with the partition wall 5. With this configuration, when the partition wall 5 is formed by a resin mold or the like, the protrusion portion 30 can be formed at the same time.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

FIG. 5 is a cross-sectional view showing a main part of a semiconductor device 1 according to a second embodiment of the present invention.
5, in the second embodiment, the substrate 6 has a first plane 7a and a second plane 7b recessed relative to the first plane 7a, and the land 23 is provided on the second plane 7b. That is, a step is provided on the front surface 7 of the substrate 6 in the second embodiment, and the land 23 is formed in the thinner portion where the step is provided.

The reference numeral 8 in FIG. 5 denotes a resist provided on the substrate 6. Although not shown in FIG. 5, a pair of protrusions 30 are formed on both sides of the land 23, as in the first embodiment. Incidentally, if the second plane 7b is formed deep and the upper end 20a of the semiconductor light emitting element 20 is at a height below the surface of the resist 8, it is not necessary to provide a wall acting as a dam on the substrate 6.

According to the second embodiment of the above configuration, the land 23 is provided on the second plane 7b recessed from the first plane 7a of the substrate 6, so that the connection interface 25 between the semiconductor light-emitting element 20 and the land 23 by the conductive adhesive 24 is not flush with the surface of the resist 8 and the first plane 7a, which are subjected to shear stress due to the stress of the transparent resin 40. This reduces the shear stress applied to the connection interface 25 between the semiconductor light-emitting element 20 and the land 23 by the conductive adhesive 24, and prevents the semiconductor light-emitting element 20 from peeling off from the land 23.

Third Embodiment
Next, a third embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

FIG. 6 is a cross-sectional view showing a main part of a semiconductor device 1 according to a third embodiment of the present invention.
6, in the third embodiment, the land 23 has an outer shape smaller than the fillet of the conductive adhesive 24 that connects the semiconductor light emitting element 20 to the land 23. In the third embodiment, a pair of protrusions 30 are formed on both sides of the land 23, similar to the first embodiment, although not shown in FIG.

The fillet of the conductive adhesive 24 is the portion that fills the corner between the side surface 20c of the semiconductor light-emitting element 20 and the surface of the land 23. The conductive adhesive 24 becomes gradually thinner as it moves away from the side surface 20c of the semiconductor light-emitting element 20. The fillet of the conductive adhesive 24 extends outward from the surface of the land 23 and contacts (adheres to) the side surface 23a of the land 23. In addition, the outer portion of the fillet of the conductive adhesive 24 extends to the surface 7 of the substrate 6 and contacts (adheres to) this surface 7.

According to the third embodiment having the above configuration, since the land 23 has a smaller outer shape than the fillet of the conductive adhesive 24, the fillet of the conductive adhesive 24 embraces the side surface 23a of the land 23, providing an anchor effect. Therefore, even if stress is applied to the semiconductor light-emitting element 20 from the transparent resin 40 due to the difference in thermal expansion with the substrate 6, it is possible to prevent the semiconductor light-emitting element 20 from peeling off from the land 23.

Although preferred embodiments of the present invention have been described and illustrated above, it should be understood that these are illustrative of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Thus, the present invention should not be considered as limited by the foregoing description, but rather by the scope of the claims.

For example, in the above embodiment, as shown in FIG. 2, the transparent resin 40 is molded up to a position higher than the upper end 30a of the protrusion 30. However, as shown in FIG. 7, the transparent resin 40 may be molded up to a position lower than the upper end 30a of the protrusion 30 and higher than the upper end 20a of the semiconductor light-emitting element 20. Even with such a configuration, the protrusion 30 can prevent the semiconductor light-emitting element 20 from peeling off from the land 23.

In addition, for example, the above second embodiment has been described on the assumption that there is a protrusion 30 (not shown), but even if there is no protrusion 30 and only the configuration shown in FIG. 5 is used, the peeling prevention effect of the semiconductor light emitting element 20 can be obtained. Therefore, a part or all of the above-mentioned second embodiment can be described as in the following supplementary note 1, but is not limited to the following.

(Appendix 1)
A substrate having lands;
A semiconductor light emitting element attached to the land;
A transparent resin that covers the semiconductor light emitting element,
the substrate has a first plane and a second plane recessed relative to the first plane;
The semiconductor device, wherein the land is provided on the second plane.

For example, the above third embodiment has been described on the assumption that there is a protrusion 30 (not shown), but even if there is no protrusion 30 and only the configuration shown in FIG. 6 is used, the peeling prevention effect of the semiconductor light emitting element 20 can be obtained. Therefore, a part or all of the above-mentioned third embodiment can be described as in Supplementary Note 2 below, but is not limited to the following.

(Appendix 2)
A substrate having lands;
A semiconductor light emitting element attached to the land;
A transparent resin that covers the semiconductor light emitting element,
The semiconductor device according to claim 1, wherein the land has an outer shape smaller than a fillet of a conductive adhesive material that connects the semiconductor light emitting element to the land.

1...semiconductor device, 2...housing, 3...light-emitting section, 4...light-receiving section, 5...partition wall, 6...substrate, 7...surface, 7a...first plane, 7b...second plane, 8...resist, 10...semiconductor light-receiving element, 11...bonding pad, 12...bonding wire, 20...semiconductor light-emitting element, 20a...top end, 20b...back side, 20c...side, 21...bonding pad, 22...bonding wire, 23...land, 23a...side, 24...conductive adhesive, 25...connection interface, 30...projection, 30a...top end, 30b...side, 40...transparent resin

Claims (6)

A substrate having lands;
A housing that encloses the substrate;
A semiconductor light emitting element attached to the land;
A transparent resin that covers the semiconductor light emitting element;
a protrusion disposed inside the housing, protruding from a periphery of the land higher than an upper end of the semiconductor light emitting element and in contact with the transparent resin;
The transparent resin is molded to a position higher than the upper end of the protrusion,
a side surface of the protrusion portion facing a side surface of the semiconductor light emitting element across the transparent resin in a plate surface direction along the surface of the substrate, the side surface of the protrusion portion being opposed to a side surface of the semiconductor light emitting element across the transparent resin. The semiconductor device according to claim 1, characterized in that the protrusions are provided in pairs, sandwiching the land. The semiconductor device according to claim 1 or 2, characterized in that the protrusion extends linearly along the land in a plan view. The semiconductor device according to claim 1 or 2, characterized in that the protrusions are provided in a spot shape along the land in a plan view. the substrate has a first plane and a second plane recessed relative to the first plane;
5. The semiconductor device according to claim 1, wherein the land is provided on the second plane. The semiconductor device according to any one of claims 1 to 5, characterized in that the land has an outer shape smaller than a fillet of conductive adhesive that connects the semiconductor light-emitting element to the land.

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