Semiconductor device

Abstract

To enable suppressing an increase in a wire length and heat resistance while suppressing a short-circuit caused by a solder overflow in a semiconductor device in which a semiconductor element to which a wire is connected is joined by solder.SOLUTION: In a semiconductor device, a semiconductor element 2 is mounted on an element mounting part 42 of a substrate 4 by a solder joint material 3. A solder absorption part 44 into which an excessive portion of the solder joint material 3 flows is run from the element mounting part 42. The substrate 4 is arranged separated from the element mounting part 42, and includes a plurality of bonding parts 43 wire-connected to the semiconductor element 2. The solder absorption part 44 has higher solder wettability than other parts of the substrate 4, and is electrically independent from the plurality of bonding parts 43.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a semiconductor device in which a semiconductor element is mounted on a substrate or the like via a bonding material.

Background Art

[0002] Conventionally, a semiconductor device is known in which a semiconductor element is mounted on a circuit board via a bonding material mainly composed of solder, and the semiconductor element and the circuit board are wire-connected. In this type of semiconductor device, when an excess portion occurs in the solder, the overflowed solder may flow into the portion of the circuit board where the wire connection is made, resulting in a short circuit. As a semiconductor device capable of suppressing such a short circuit, for example, the one described in Patent Document 1 can be mentioned.

[0003] The semiconductor device described in Patent Document 1 includes a circuit board having a mounting portion on which a semiconductor element is mounted and a protruding portion that surrounds the mounting portion and protrudes from the upper surface of the semiconductor element, and the semiconductor element is bonded to the mounting portion via solder.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the semiconductor device described in Patent Document 1, while short circuit suppression can be achieved by blocking the excess solder by the protruding portion, since the wire connected to the semiconductor element is connected to a portion located outside the protruding portion, the wire length becomes long. Further, Patent Document 1 also describes a structure in which a groove for passing the wire is provided in the protruding portion in order to shorten the wire length, but this structure requires a separate processing step, resulting in an increase in manufacturing cost.

[0006] Also, as a method for suppressing a short circuit caused by the overflow of the excess solder, a concave portion is provided inside the mounting area of the circuit board on which the semiconductor element is mounted, solder is disposed in the concave portion, and the semiconductor element and the circuit board are solder-bonded. However, in this method, since the solder thickness increases, the thermal resistance between the semiconductor element and the circuit board increases, and the heat dissipation property of the semiconductor element deteriorates.

[0007] In view of the above points, the present invention provides a semiconductor device in which a semiconductor element is mounted on an object to be mounted such as a circuit board via a bonding material, and the semiconductor element is wire-connected to the object to be mounted, and suppresses a short circuit caused by the overflow of the bonding material, while suppressing an increase in wire length and thermal resistance.

Means for Solving the Problems

[0008] To achieve the above object, the semiconductor device according to claim 1 is a semiconductor device, including a semiconductor element (2) having one surface (2a) and the other surface (2b) that are in a front-back relationship, and a plurality of electrode portions (21) on one surface; an element mounting portion (42) to which the other surface of the semiconductor element is bonded via a solder bonding material (3); a plurality of bonding portions (43) that are arranged apart from each other around the mounting portion; a solder absorption portion (44) that extends from the element mounting portion toward the outside and into which an excess portion of the solder bonding material flows, and is electrically independent of the bonding portions; and a wire (5) that connects the electrode portions and the bonding portions. , a lid material (6) mounted on a substrate, covering a semiconductor element and a wire at a distance, and a lid material mounting portion (45) in a frame shape provided on the substrate and surrounding the element mounting portion and a plurality of bonding portions The element mounting portion and the solder absorption portion have higher solder wettability than other portions of the substrate. , wherein the semiconductor element is an optical semiconductor element, at least a part of the portion of the lid material located above the semiconductor element is a light transmission portion (61) that transmits light, and a part of the solder absorption portion is disposed between the bonding portion and the lid material mounting portion .

[0009] This semiconductor device is formed by mounting a semiconductor element on a substrate having an element mounting portion on which the semiconductor element is mounted, a bonding portion wire-connected to the semiconductor element, and a solder absorption portion extending from the element mounting portion via a solder bonding material. The solder absorption portion is electrically independent of the bonding portion and has higher solder wettability than other parts of the substrate. Therefore, even when an excess portion occurs in the solder bonding material, the excess portion flows into the solder absorption portion having higher solder wettability than other parts of the substrate, thereby suppressing the occurrence of a short circuit due to contact with the bonding portion. Further, this semiconductor device has a structure in which the solder absorption portion extends from the element mounting portion, and there is no need to provide a protruding portion for suppressing solder overflow between the element mounting portion and the bonding portion, and the thickness of the solder bonding material does not increase. As a result, this semiconductor device can achieve both suppression of short circuits caused by overflow of excess solder and suppression of increase in wire length and thermal resistance.

[0010] Note that the reference numerals in parentheses attached to each component etc. show an example of the correspondence relationship between the component etc. and the specific components etc. described in the embodiments described later.

Brief Description of Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each of the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals for description.

[0013] (First Embodiment) The semiconductor device 1 of the first embodiment will be described with reference to the drawings.

[0014] In FIG. 4, in order to clearly show the overflow of the excess solder bonding material 3 in the semiconductor device 100 of the comparative example described later, although a cross-section is not shown, hatching is applied to the solder bonding material 3 and the lid member 6 is omitted. In FIG. 5, the spreading direction of the excess solder bonding material 3 to the solder absorption portion 44 described later is indicated by a white arrow.

[0015] As shown in FIG. 1, for example, the semiconductor device 1 of the present embodiment includes a semiconductor element 2, a solder bonding material 3, a substrate 4, a wire 5, a lid member 6, and a heat dissipation member 7. In the semiconductor device 1, the semiconductor element 2 is bonded to the substrate 4 by the solder bonding material 3, and the semiconductor element 2 is connected to the substrate 4 by a plurality of wires 5. For example, in the semiconductor device 1, the semiconductor element 2 is an optical semiconductor element, and in a state where the region connected by the wire 5 among the semiconductor element 2 and the substrate 4 is covered and sealed by the lid member 6, it is an optical semiconductor device that irradiates light to the outside and receives light from the outside.

[0016] In this specification, the case where the semiconductor device 1 is configured as an optical semiconductor device is described as a representative example, but the present invention is not limited to this configuration.

[0017] The semiconductor element 2 is, for example, in a plate shape having a front surface 2a and a back surface 2b that are in a front-back relationship, and is manufactured by a known semiconductor process using a semiconductor material such as Si (silicon) or SiC (silicon carbide). The semiconductor element 2 includes, for example, a plurality of electrodes 21 and a laser diode 22 on one surface 2a, and is an optical semiconductor element capable of irradiating laser light of a predetermined wavelength to the outside. The semiconductor element 2 can be configured to include, for example, a light receiving portion (not shown), receive the reflected light of the laser light irradiated to the outside, and output a signal corresponding to the amount of the light. The other surface 2b of the semiconductor element 2 is bonded to the element mounting portion 42 of the substrate 4 by the solder bonding material 3. In the semiconductor element 2, for example, the wire 5 is connected to the plurality of electrodes 21 and the laser diode 22 on the one surface 2a, and is electrically connected to the bonding portion 43 of the substrate 4 via the wire 5.

[0018] The plurality of electrodes 21 are made of a conductive material such as Al (aluminum), and are formed by a vacuum process such as vapor deposition. The plurality of electrodes 21 are arranged, for example, apart from each other on one surface 2a, and different wires 5 are connected thereto by wire bonding.

[0019] The laser diode 22 includes, for example, an N-type region, a P-type region, and a light-emitting layer (not shown), and has a double heterostructure in which the light-emitting layer is sandwiched between these two regions. When a voltage is applied to the laser diode 22 via the wire 5, laser light of a predetermined wavelength is generated. The laser light generated by the laser diode 22 is irradiated outward from the one surface 2a through a light guide path (not shown) of the semiconductor element 2, for example. Note that the material of the light-emitting layer of the laser diode 22 is, for example, InGaN (wavelength: 400 nm to 530 nm), AlGaInP (wavelength: 635 nm to 680 nm), AlGaAs (wavelength: 780 nm to 850 nm), etc., and is appropriately changed according to the wavelength of the laser light. In addition, the constituent materials of the laser diode 22 when generating visible light are not limited to the above examples, and may have a configuration for generating infrared light having a wavelength of 900 nm or more.

[0020] The solder joint material 3 is made of a joint material mainly composed of Sn (tin), and is used for joining between the constituent members of the semiconductor device 1. The solder joint material 3 is, for example, SnAg (tin-silver), SnCu (tin-copper), SnAgCu (tin-silver-copper), etc., but is not limited thereto.

[0021] The substrate 4 includes, for example, as shown in FIGS. 1 and 2, a base material 41, an element mounting portion 42, a plurality of bonding portions 43, a solder absorption portion 44, and a lid material mounting portion 45. For example, on the surface 41a of the base material 41, the element mounting portion 42, the plurality of bonding portions 43, the solder absorption portion 44, and the lid material mounting portion 45 are formed, and on the back surface 41b of the base material 41, a heat dissipation member 7 is joined by an adhesive (not shown). Note that other electronic components or the like may be mounted in the outer region of the lid material 6 on the substrate 4.

[0022] The base material 41 is made of an insulating ceramic material such as alumina or alumina zirconia, but may be made of other insulating materials such as glass epoxy resin.

[0023] The element mounting portion 42 is a portion where the semiconductor element 2 is mounted by the solder bonding material 3, and has a shape that conforms to the outer shape of the semiconductor element 2. The element mounting portion 42 is, for example, substantially square-shaped, and all of the sides forming the outer contour face a plurality of bonding portions 43. Hereinafter, for convenience of explanation, the side of the outer contour of the element mounting portion 42 that faces the bonding portion 43 is referred to as the "opposing side 42a". In FIG. 2, an example is shown in which all four sides forming the outer contour of the element mounting portion 42 are opposing sides 42a, but the present invention is not limited to this example. Further, the element mounting portion 42 is not limited to a substantially square shape, and may be a polygonal shape having a plurality of sides forming the outer contour, and the shape thereof can be appropriately changed according to the outer shape of the semiconductor element 2 and the like.

[0024] The solder absorption portion 44 extends at least at one end located outside the region facing one or a plurality of bonding portions 43 among the opposing sides 42a of the element mounting portion 42. The element mounting portion 42, together with the solder absorption portion 44, has a configuration with higher solder wettability than other portions of the substrate 4. The element mounting portion 42 has, for example, a structure in which a metal film 422 with high solder wettability is laminated on a conductive portion 421 made of a conductive material such as Cu or an alloy thereof, as shown in FIG. 3. Here, the "high solder wettability" means a state where the contact angle of the solder is smaller than that of Cu (contact angle: about 43°).

[0025] The metal film 422 is made of a metal material with high solder wettability, such as Au (gold) on the outermost surface, for example. The metal film 422 is, for example, a single Au film or a laminated film laminated in the order of Ni (nickel) / Au or Ni / Pd (palladium) / Au from the base material 41 side, but is not limited to these configurations and materials.

[0026] The bonding portion 43 is the part to which the wire 5 is connected and is made of, for example, a conductive material such as Cu or Au. The bonding portions 43 are arranged in plurality, separated from each other so as to surround the element mounting portion 42, and are all electrically independent of the element mounting portion 42 and the solder absorbing portion 44. The bonding portion 43 is connected to the wire 5 by wire bonding and is also connected to a circuit wiring (not shown) of the substrate 4.

[0027] The solder absorbing portion 44 is a member integral with the element mounting portion 42 and is a part that absorbs the surplus portion when a surplus portion occurs in the solder bonding material 3 disposed on the element mounting portion 42. The solder absorbing portion 44, together with the element mounting portion 42, is configured to have a higher wettability of solder than other parts of the substrate 4.

[0028] Here, for example, as shown in FIG. 4, a semiconductor device 100 of a comparative example without the solder absorbing portion 44 will be described. In the semiconductor device 1 of the comparative example, when a surplus portion occurs in the solder bonding material 3 disposed on the element mounting portion 42, since there is no place for the surplus portion to go, the surplus portion overflows outside the element mounting portion 42. When this overflow of the solder bonding material 3 occurs, the element mounting portion 42 and the bonding portion 43 to which the wire 5 is connected are electrically connected by the solder bonding material 3, resulting in a short circuit.

[0029] On the other hand, when the substrate 4 having the solder absorbing portion 44 is used, the solder bonding material 3 on the element mounting portion 42 will wet and spread to the solder absorbing portion 44 having a relatively higher wettability of solder with respect to the surplus portion. That is, the solder absorbing portion 44 plays a role of suppressing the surplus portion of the solder bonding material 3 from preferentially wetting and spreading and flowing in, and the surplus portion from overflowing outside the element mounting portion 42, as indicated by the white arrow in FIG. 5 for example. Thereby, it is possible to suppress the occurrence of a short circuit due to the overflow of the solder bonding material 3 on the element mounting portion 42 and the wetting and spreading to the bonding portion 43 disposed around it.

[0030] The solder absorption part 44 has the same configuration as the element mounting part 42, that is, a configuration in which a metal film 442 is laminated on a conductive part 441, as shown in FIG. 6, for example. The solder absorption part 44 is formed by electrolytic plating or electroless plating, for example, simultaneously with the element mounting part 42. The conductive part 441 is made of the same conductive material as the conductive part 421. The metal film 442 is formed of the same conductive material as the metal film 422 and has a single-layer or laminated structure.

[0031] The solder absorption part 44 is provided on at least one of the opposing sides 42a when there are a plurality of opposing sides 42a in the element mounting part 42, as shown in FIG. 2, for example. The solder absorption part 44 may be provided only one in the element mounting part 42, or a plurality of solder absorption parts 44 may be provided, for example, two, three, four, etc. as shown in FIGS. 7 to 9. When a plurality of solder absorption parts 44 are provided in the element mounting part 42, it is only necessary that they be arranged outside at least one or a plurality of portions facing the bonding parts 43 among the opposing sides 42a, and the arrangement may be appropriately changed. In other words, the solder absorption part 44 is provided at at least one of the plurality of corner parts of the element mounting part 42, which are adjacent to the opposing sides 42a.

[0032] The lid material mounting part 45 is a part where the lid material 6 is mounted by a solder bonding material 3 or the like. The lid material mounting part 45 is arranged outside the element mounting part 42 and a plurality of bonding parts 43 arranged around it, and has a frame shape surrounding them. The lid material mounting part 45 has the same configuration as the element mounting part 42 or the bonding part 43, for example, and is formed by electrolytic plating or electroless plating.

[0033] The wire 5 is made of a conductive material such as Au, for example. The wire 5 is connected to the semiconductor element 2 and the bonding part 43 by wire bonding to electrically connect them.

[0034] The lid member 6 is, for example, as shown in FIG. 1, a box-shaped member that forms an enclosed space covering the region where the semiconductor element 2 and the wire 5 are connected when mounted on the lid member mounting portion 45, and can also be referred to as a "lid". The lid member 6 is made such that a laser beam can be irradiated from the semiconductor element 2 to the outside. For example, a part of the top plate portion located on one surface 2a of the semiconductor element 2 is a light-transmitting portion 61. The lid member 6 is, for example, a metal lid whose base is made of a metal material such as an alloy of Fe (iron) and Ni, and has a configuration in which a light-transmitting portion 61 made of a light-transmitting material such as glass is attached to the recess. Note that the enclosed space formed when the lid member 6 is attached to the lid member mounting portion 45 is in an inert gas atmosphere such as N2.

[0035] The heat radiating member 7 is, for example, a heat sink, and is attached to the back surface 41b of the base material 41 by an adhesive or the like (not shown), and is a member that radiates the heat of the semiconductor element 2 transmitted to the base material 41 to the outside. The heat radiating member 7 has, for example, a shape having a large number of fins of an arbitrary shape.

[0036] The above is the basic configuration of the semiconductor device 1 of the present embodiment.

[0037] According to this embodiment, the substrate 4 has a solder absorption portion 44 extending from the element mounting portion 42. When the semiconductor element 2 is mounted on the element mounting portion 42, even if an excess portion of the solder bonding material 3 is generated, the semiconductor device 1 has a structure in which the excess portion preferentially wets and spreads on the solder absorption portion 44. As a result, the excess portion of the solder bonding material 3 is prevented from overflowing outside the element mounting portion 42 and coming into contact with the bonding portion 43 connected by the semiconductor element 2 and the wire 5, so that the occurrence of a short circuit due to the solder bonding material 3 can be suppressed. Further, since the solder absorption portion 44 is disposed outside a portion of the opposing side 42a of the element mounting portion 42 that faces the bonding portion 43, the distance between the semiconductor element 2 and the bonding portion 43 does not increase, and the wire length can be shortened. In addition, since the semiconductor device 1 does not have a recess in the region directly below the semiconductor element 2, the thickness of the solder bonding material 3 that joins the semiconductor element 2 and the element mounting portion 42 does not increase compared to the case where such a recess is present, and the structure is such that an increase in thermal resistance is suppressed. Therefore, the semiconductor device 1 of this embodiment can obtain the effects of suppressing a short circuit caused by the solder bonding material 3 for mounting the semiconductor element 2 on the substrate 4, suppressing an increase in wire length, and suppressing an increase in thermal resistance due to the solder bonding material 3.

[0038] (Second Embodiment) The semiconductor device 1 of the second embodiment will be described with reference to the drawings.

[0039] The semiconductor device 1 of this embodiment is different from the first embodiment in that the shape of the solder absorption portion 44 is changed, as shown in FIG. 10, for example. In this embodiment, this difference will be mainly described.

[0040] In this embodiment, the solder absorption portion 44 extends from both ends of the region of the opposing side 42a of the element mounting portion 42 that faces a plurality of bonding portions 43, and has a shape in which the portions extending from both ends are connected. A part of the solder absorption portion 44 is disposed between the bonding portion 43 and the lid member mounting portion 45, and together with the element mounting portion 42, has a frame shape surrounding the plurality of bonding portions 43. Only one solder absorption portion 44 may be formed on the element mounting portion 42, or a plurality of solder absorption portions 44 may be formed, for example, two, three, four, etc. as shown in FIGS. 11 to 13, on the element mounting portion 42. Even in the case of the substrate 4 in which the outer shape of the element mounting portion 42 is substantially rectangular and all four sides thereof are surrounded by a plurality of bonding portions 43, the solder absorption portion 44 does not necessarily have to be provided on all four sides, and the number thereof can be appropriately changed.

[0041] Also according to this embodiment, the semiconductor device 1 that obtains the same effect as the first embodiment is obtained. Further, since the solder absorption portion 44 of the semiconductor device 1 has a frame shape in which it is connected to the element mounting portion 42 at two locations, the number of paths through which the surplus portion of the solder bonding material 3 disposed on the element mounting portion 42 spreads by wetting increases, and the effect of suppressing the overflow of the solder bonding material 3 toward the bonding portion 43 side is further improved.

[0042] (Third Embodiment) The semiconductor device 1 of the third embodiment will be described with reference to the drawings.

[0043] The semiconductor device 1 of this embodiment is different from the first embodiment in that, as shown in FIG. 14 for example, one solder absorption portion 44 has a shape that individually surrounds a plurality of bonding portions 43. In this embodiment, this difference will be mainly described.

[0044] The solder absorption portion 44 is, for example, as shown in FIG. 14, in addition to being in a frame shape surrounding a plurality of bonding portions 43 together with the element mounting portion 42 as in the second embodiment, in this embodiment, it has a lattice shape partitioning the bonding portions 43 from each other. The solder absorption portion 44 may be formed only one on the element mounting portion 42, or may be formed in a plurality, such as two, three, four, etc. on the element mounting portion 42 as shown in FIGS. 15 to 17 for example. The number of solder absorption portions 44 provided on the element mounting portion 42 can be appropriately changed according to the number and arrangement of the bonding portions 43 and the like.

[0045] Also according to this embodiment, the semiconductor device 1 can obtain the same effects as those of the first embodiment. In addition, since the connection points between the solder absorption portion 44 and the element mounting portion 42 are three or more, and the paths for the surplus portion of the solder bonding material 3 to flow in increase further, the semiconductor device 1 has a structure with an even more improved short-circuit suppression effect than the above-described embodiments.

[0046] (Other Embodiments) Although the present disclosure has been described based on the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within an equivalent range. In addition, various combinations and forms, and further, other combinations and forms including only one, more, or less of those elements are also within the scope and spirit of the present disclosure.

[0047] (1) In each of the above embodiments, the semiconductor element 2 is an optical semiconductor element, and the structure in which the lid material 6 surrounding the semiconductor element 2 is attached to the substrate 4 has been described as a representative example. However, the semiconductor device 1 is not limited to this representative example. For example, the semiconductor device 1 may have a structure in which a semiconductor element 2 other than the optical semiconductor element is connected to the substrate 4 having the solder absorption portion 44 by the solder bonding material 3 and the wire 5, and may not have some constituent members such as the lid material 6 and the heat dissipation member 7. In this case, the semiconductor element 2 may have an arbitrary configuration, such as a configuration having a sensor portion that outputs a signal corresponding to a physical quantity when a physical quantity such as acceleration, angular velocity, or pressure is applied, or a configuration having an arbitrary integrated circuit.

[0048] (2) In each of the above embodiments, the solder absorption portion 44 is not limited to the illustrated shape examples, and may be circular, elliptical, an elliptical frame, etc., may be branched, and its shape may be appropriately changed. Further, the semiconductor device 1 may be configured to include two or more types of solder absorption portions 44 in each of the above embodiments.

Explanation of Signs

[0049] 2 ··· semiconductor element, 2a ··· one surface, 2b ··· the other surface, 21 ··· electrode, 3 ··· solder bonding material, 4 ··· substrate, 42 ··· element mounting portion, 42a ··· opposing side, 422 ··· metal film, 43 ··· bonding portion, 44 ··· solder absorption portion, 442 ··· metal film, 45 ··· lid material mounting portion, 5 ··· wire, 6 ··· lid material, 61 ··· light transmission portion

Claims

1. A semiconductor device, comprising: a semiconductor element (2) having a front surface (2a) and a back surface (2b) that are in a front-back relationship, and a plurality of electrodes (21) on the front surface; an element mounting portion (42) to which the back surface of the semiconductor element is joined via a solder bonding material (3); a plurality of bonding portions (43) that are arranged separately from each other around the element mounting portion; and a solder absorption portion (44) that extends from the element mounting portion toward the outside and into which an excess portion of the solder bonding material flows, and that is electrically independent from the bonding portions, on a substrate (4); a wire (5) connecting the electrodes and the bonding portions; a lid member (6) that is mounted on the substrate and covers the semiconductor element and the wire with a distance therebetween; a lid member mounting portion (45) that is provided on the substrate and has a frame shape surrounding the element mounting portion and the plurality of bonding portions; the element mounting portion and the solder absorption portion have higher solder wettability than other portions of the substrate; the semiconductor element is an optical semiconductor element; at least a part of a portion of the lid member located above the semiconductor element is a light transmission portion (61) that transmits light; a part of the solder absorption portion is disposed between the bonding portion and the lid member mounting portion. A semiconductor device.

2. The semiconductor device according to claim 1, wherein the solder absorption portion has a frame shape that surrounds each of a part of the plurality of bonding portions together with the element mounting portion one by one.

3. The semiconductor device according to claim 1 or 2, wherein the element mounting portion and the solder absorption portion are covered with a metal film (422, 442).

4. The semiconductor device according to claim 3, wherein the metal film is either a single Au film or a laminated film laminated in the order of Au / Ni or Au / Pd / Ni from the outermost surface side.

5. The semiconductor device according to any one of claims 1 to 4, wherein the solder bonding material is made of a material containing Sn as a main component.

6. The element mounting portion has a polygonal shape having a plurality of sides forming an outer perimeter, and has at least one solder absorption portion, With a side facing the bonding portion among the plurality of sides as a facing side (42a), the solder absorption portion is disposed at one end or both ends of a portion facing one or more of the bonding portions among the facing sides. The semiconductor device according to any one of claims 1 to 5.

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