Semiconductor equipment

Abstract

To provide a semiconductor device that can improve performance. [Solution] The semiconductor device of the embodiment comprises a conductive member 21, a conductive member 23, a semiconductor chip 10 provided between the conductive member 21 and the conductive member 23, a connecting member 32 provided between the semiconductor chip 10 and the conductive member 23, and a thin film 51 provided on the conductive member 23 and containing a material different from that of the connecting member 32. The conductive member 23 has plate portions 23a, 23b, and 23c. Plate portion 23a extends in the X direction along the first surface of the semiconductor chip 10 and is connected to the semiconductor chip 10 via the connecting member 32. Plate portion 23b extends diagonally from plate portion 23a with respect to the X direction. Plate portion 23c extends in the X direction from plate portion 23b. The thin film 51 is arranged on the surface of plate portion 23b that is continuous with the surface on which the connecting member 32 is provided.

Description

Technical Field

[0001] Embodiments of the present invention relate to a semiconductor device.

Background Art

[0002] A semiconductor device including a semiconductor package having a semiconductor chip mounted thereon is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] To provide a semiconductor device capable of improving performance.

Means for Solving the Problems

[0005] The semiconductor device of the embodiment includes a first conductive member, a second conductive member, a semiconductor chip provided between the first conductive member and the second conductive member, a first connection member provided between the semiconductor chip and the second conductive member, and a thin film provided on the second conductive member and including a material different from that of the first connection member. The second conductive member has a first plate portion, a second plate portion, and a third plate portion. The first plate portion extends in a first direction along a first surface of the semiconductor chip and is connected to the semiconductor chip via the first connection member. The second plate portion extends obliquely with respect to the first direction from the first plate portion. The third plate portion extends in the first direction from the second plate portion. The thin film is disposed on a surface of the second plate portion that is continuous with a surface where the first connection member is provided.

Brief Description of the Drawings

[0006] [Figure 1]This is a perspective view showing the external shape of a semiconductor device according to the first embodiment. [Figure 2] This is a plan view showing the external shape of a semiconductor device according to the first embodiment. [Figure 3] This is a cross-sectional view showing the configuration of a semiconductor device according to the first embodiment. [Figure 4] This is a cross-sectional view showing a connection structure between a semiconductor chip and a conductive member according to the first embodiment. [Figure 5] This is a cross-sectional view showing the connection structure between a semiconductor chip and a conductive material in a comparative example. [Figure 6] This is a cross-sectional view showing a connection structure between a semiconductor chip and a conductive member according to the second embodiment. [Figure 7] This is a cross-sectional view showing a connection structure between a semiconductor chip and a conductive member according to the third embodiment. [Modes for carrying out the invention]

[0007] The embodiments will be described below with reference to the drawings. In the following description, components having the same function and configuration will be denoted by the same reference numerals. Furthermore, the embodiments shown below are illustrative examples of devices and methods for realizing the technical concept of this embodiment, and do not specify the materials, shapes, structures, and arrangements of the components as described below.

[0008] 1. First Embodiment A semiconductor device of the first embodiment will now be described. Figure 1 is a perspective view showing the external shape of the semiconductor device of the first embodiment. Figure 2 is a plan view showing the external shape of the semiconductor device of the first embodiment. Figure 3 is a cross-sectional view of the semiconductor device along line III-III in Figures 1 and 2. Figures 1 and 2 are views seen through the resin member covering the semiconductor device. In the following description, in Figures 1 to 3, the direction of the arrow in the X direction will be simply referred to as the X direction, and the direction opposite to the arrow will be referred to as the -X direction. Similarly, for the Y and Z directions, the directions of the arrows in the Y and Z directions will be simply referred to as the Y and Z directions, respectively, and the directions opposite to the arrows will be referred to as the -Y and -Z directions, respectively. In addition, the Z direction may be referred to as up, and the -Z direction as down.

[0009] As shown in Figure 3, the semiconductor device 1 comprises a semiconductor chip 10, conductive members 21-25, connecting members 31-33, and a resin member 40. The semiconductor chip 10 is provided between conductive member 21 and conductive member 23. Furthermore, conductive member 23 is provided on conductive member 22.

[0010] The semiconductor chip 10 includes, for example, a MOS-type field-effect transistor (metal oxide semiconductor field effect transistor: MOSFET) or an insulated gate bipolar transistor (IGBT). Here, we will explain the case where the semiconductor chip 10 is a MOSFET.

[0011] The semiconductor chip 10 includes, for example, a source electrode 10s, a drain electrode 10d, a gate electrode 10g, and a semiconductor layer 10a. The semiconductor layer 10a is provided between the source electrode 10s and the drain electrode 10d. The source electrode 10s and the drain electrode 10d may be swapped as needed.

[0012] The semiconductor chip 10 has a first surface and a second surface. The first surface is located on the Z-direction side, and the second surface is located on the -Z-direction side. A source electrode 10s is provided on the first surface of the semiconductor chip 10. A drain electrode 10d is provided on the second surface of the semiconductor chip 10.

[0013] The conductive member 21 is part of the lead frame on which the semiconductor chip 10 is mounted. The conductive member 21 has a base portion 21a and a plurality of protrusions 21b. The conductive member 21 mainly contains a conductive material such as copper.

[0014] The base portion 21a is an area where the semiconductor chip 10 is placed. The semiconductor chip 10 is provided on the base portion 21a of the conductive member 21. The conductive member 21 is arranged to face the drain electrode 10d of the semiconductor chip 10 and is electrically connected to the drain electrode 10d.

[0015] The plurality of protruding portions 21b are areas extending in the -X direction from the base portion 21a. The plurality of protruding portions 21b function as lead terminals (for example, drain terminals) capable of connection to the outside.

[0016] A connection member 31 is provided between the semiconductor chip 10 and the conductive member 21. The connection member 31 fixes the semiconductor chip 10 to the base portion 21a of the conductive member 21. Thereby, the drain electrode 10d of the semiconductor chip 10 is electrically connected to the conductive member 21 via the connection member 31. The connection member 31 mainly contains a conductive material such as solder or silver.

[0017] The plurality of conductive members 22 are provided at a distance in the X direction from the conductive member 21 and are arranged in the Y direction. The conductive member 22 is a part of the lead frame. The conductive member 22 functions as a lead terminal (for example, source terminal) capable of connection to the outside. The conductive member 22 mainly contains a conductive material such as copper, for example.

[0018] A conductive member 23 is provided on the source electrode 10s of the semiconductor chip 10 and the conductive member 22. The conductive member 23 is arranged to face the source electrode 10s of the semiconductor chip 10 and the conductive member 22 and is electrically connected to the source electrode 10s and the conductive member 22. The conductive member 23 mainly contains a conductive material such as copper, for example.

[0019] The conductive member 23 has a portion (or first plate portion) 23a, a portion (or second plate portion) 23b, a portion (or third plate portion) 23c, and a portion (or fourth plate portion) 23d. The portion 23a is an area that faces the semiconductor chip 10 and is electrically connected to the semiconductor chip 10. The portion 23a is an area that extends along the first surface of the semiconductor chip 10, that is, an area that linearly extends in the X direction. The portion 23d is an area that faces the conductive member 22 and is electrically connected to the conductive member 22. The portions 23b and 23c are areas between the portion 23a and the portion 23d, and are areas that do not face either the semiconductor chip 10 or the conductive member 22. The portion 23b is continuous with the portion 23a and is an area that linearly extends obliquely with respect to the X direction and the Z direction from the portion 23a. The portion 23c is continuous with the portion 23b and is an area that linearly extends in the X direction from the portion 23b. Further, the portion 23d is continuous with the portion 23c, bends from the portion 23c in the -Z direction, and further extends along the upper surface of the conductive member 22, that is, an area that linearly extends in the X direction. With such a structure, by increasing the distance between the portion 23c of the conductive member 23 and the conductive member 21, the insulation between the conductive member 23 and the conductive member 21 can be enhanced.

[0020] A thin film 51 is provided on the lower surface of the portion 23b of the conductive member 23. Details of the thin film 51 will be described later.

[0021] A connection member 32 is provided between the portion 23a of the conductive member 23 and the semiconductor chip 10. The connection member 32 fixes the conductive member 23 to the semiconductor chip 10. Thereby, the source electrode 10s of the semiconductor chip 10 is electrically connected to the conductive member 23 via the connection member 32. The connection member 32 mainly contains a conductive material such as solder or silver.

[0022] A connection member 33 is provided between the portion 23d of the conductive member 23 and the conductive member 22. The connection member 33 fixes the conductive member 23 to the conductive member 22. Thereby, the conductive member 22 is electrically connected to the conductive member 23 via the connection member 33. The connection member 33 mainly contains a conductive material such as solder or silver.

[0023] As shown in Figures 1 and 2, the conductive member 24 is provided at a distance from the conductive member 22 in the Y direction. The conductive member 24 is part of the lead frame. The conductive member 24 functions as a lead terminal (e.g., a gate terminal) that can be connected to the outside. The conductive member 24 mainly contains a conductive material such as copper.

[0024] A conductive member 25 is provided on the gate electrode 10g and conductive member 24 of the semiconductor chip 10. The conductive member 25 is positioned opposite the gate electrode 10g and conductive member 24 of the semiconductor chip 10 and is electrically connected to the gate electrode 10g and conductive member 24. The conductive member 25 mainly contains a conductive material such as copper.

[0025] Furthermore, the resin member 40 covers the semiconductor chip 10, part of the conductive member 21, part of the conductive member 22, conductive member 23, part of the conductive member 24, and conductive member 25. The resin member 40 resin-encapsulates the semiconductor chip 10 and the conductive members 21-25.

[0026] Next, with reference to Figure 4, the connection structure between the semiconductor chip 10 and the conductive member 23 will be described. Figure 4 is an enlarged view of part A in Figure 3, and is a cross-sectional view showing the connection structure between the source electrode 10s of the semiconductor chip 10 and the conductive member 23.

[0027] As described above, the source electrode 10s of the semiconductor chip 10 is connected to portion 23a of the conductive member 23 via a connecting member 32. The conductive member 23 has a portion 23a that extends linearly in the X direction, a portion 23b that extends linearly from portion 23a obliquely to the X and Z directions, and a portion 23c that extends linearly from portion 23b in the X direction.

[0028] A connecting member 32 is provided between the source electrode 10s of the semiconductor chip 10 and portion 23a of the conductive member 23. A thin film 51 is provided on the lower surface of portion 23b of the conductive member 23, that is, on the surface of portion 23b in the X direction (or -Z direction). In other words, the thin film 51 is provided on the lower surface of portion 23b of the conductive member 23 on the connecting member 32, that is, on the surface continuous with the surface on which the connecting member 32 is provided. The thin film 51 is in contact with the connecting member 32.

[0029] The thin film 51 is placed on a linearly extending surface (or region) of portion 23b of the conductive member 23. The thin film 51 is placed from the beginning of the linearly extending surface of portion 23b to partway along the linearly extending surface. For example, the thin film 51 is placed from the beginning of the linearly extending surface of portion 23b to a length of approximately 200 μm. This 200 μm length is a constraint when the film is formed by plating, and if it is possible to form a film shorter or longer than this by plating or other manufacturing methods, the length may be set to less than or greater than 200 μm.

[0030] The thin film 51 may also be positioned from the beginning of the linearly stretched surface of portion 23b to partway through portion 23c, or to the end of portion 23c, or to partway through portion 23d. Preferably, as described above, the thin film 51 is positioned from the beginning of the linearly stretched surface of portion 23b to partway through the linearly stretched surface. Alternatively, the thin film 51 is positioned from the beginning to the end of the linearly stretched surface of portion 23b. In other words, it is positioned from the beginning to the end of the linearly stretched surface of portion 23b.

[0031] Since the adhesion between the resin constituting the resin member 40 and the thin film 51 is inferior to the adhesion between the copper constituting the conductive member 23 and the resin, it is preferable that the area in which the thin film 51 is placed be small. By placing the thin film 51 from the beginning of the linearly extended surface of portion 23b to the middle of the linearly extended surface, or to the end of the linearly extended surface, the contact area between the thin film 51 and the resin can be reduced, thereby suppressing a decrease in the adhesion between the conductive member 23 and the resin.

[0032] The length of the thin film 51 in the Y direction is set to be equal to or less than the length of portion 23b of the conductive member 23 in the Y direction, as shown in Figure 2.

[0033] As mentioned above, the conductive member 23 contains, for example, copper. The thin film 51 mainly comprises a material different from that of the connecting member 32 and the conductive member 23. The thin film 51 includes a metal whose wettability of the connecting member 32 is worse than that of copper; in other words, it includes a metal that does not wet the connecting member 32 as easily as copper. The thin film 51 mainly comprises, for example, nickel (Ni) or aluminum (Al). The thin film 51 containing nickel or aluminum is formed, for example, by plating.

[0034] The thin film 51 may also contain a metal oxide film, such as copper oxide, nickel oxide, or aluminum oxide. The thickness of the metal oxide film is, for example, about 30 nm. The thin film 51 may also be an organic film, such as solder resist.

[0035] Furthermore, if the thin film 51 is copper oxide and the conductive member 23 is copper, copper oxide will form as a native oxide film on the surface of the conductive member 23 that is not in contact with the thin film 51 or other components. The thin film 51 is distinct from such a native oxide film. For example, the thickness of the native oxide film is about 2 nm, while the thickness of the thin film 51 is about 30 nm. The thin film 51 is thicker than the native oxide film. Moreover, the oxygen density contained in the thin film 51 is higher than that of the native oxide film.

[0036] The following describes the problems in the comparative example semiconductor device 100 with reference to Figure 5, and then the effects of this embodiment. Figure 5 is an enlarged cross-sectional view showing the connection structure between the semiconductor chip 10 and the conductive member 23 in the comparative example semiconductor device 100.

[0037] In the comparative example semiconductor device 100, a thin film is not provided on the underside of portion 23b of the conductive member 23. In such a structure, as shown in Figure 5, the connecting member 32 may creep up from the edge of the region where the semiconductor chip 10 and portion 23a are connected to portion 23b, forming a large fillet 32f of the connecting member 32. When such a fillet 32f is formed, the amount of connecting member 32 becomes insufficient, which may result in the formation of a cavity between the semiconductor chip 10 and the conductive member 23 where no connecting member 32 exists. In this case, the connection area between the semiconductor chip 10 and the conductive member 23 becomes insufficient, and the resistance value at the source electrode increases. Furthermore, the amount of current supplied to the semiconductor chip 10 decreases, resulting in problems such as the semiconductor chip 10 not being able to fully perform.

[0038] Furthermore, if there is a cavity between the semiconductor chip 10 and the conductive member 23, some of the resin from the resin member 40 may enter the cavity during its formation. When resin enters the cavity, thermal stress such as temperature changes due to the external environment or heat generated in the semiconductor device may increase the thermal stress on the tip of the semiconductor chip 10 and the conductive member 23 where the resin has entered. This increase in thermal stress may cause fracture at the interface between the semiconductor chip 10 and the connecting member 32, and at the interface between the conductive member 23 and the connecting member 32.

[0039] In the semiconductor device 1 of this embodiment, a thin film 51 is provided on the lower surface of portion 23b of the conductive member 23, that is, on the same surface as the surface on which the connecting member (for example, solder) 32 is provided.

[0040] By providing a thin film 51 on portion 23b of the conductive member 23, the amount of the connecting member 32 creeping up onto portion 23b can be limited, and the size of the fillet formed at the end of portion 23a can be controlled. Since the thin film 51 is a film with worse wettability than the copper that constitutes the conductive member 23, it can prevent the connecting member 32 from creeping up onto portion 23b.

[0041] This reduces the formation of cavities between the semiconductor chip 10 and the conductive member 23. As a result, sufficient connection area between the semiconductor chip 10 and the conductive member 23 can be secured, preventing an increase in resistance. Furthermore, a decrease in the amount of current supplied to the semiconductor chip 10 can be prevented, allowing the semiconductor chip 10 to perform to its full potential.

[0042] Furthermore, since the formation of cavities can be reduced, it is possible to prevent resin from entering the cavities and suppress thermal stress on the tip of the semiconductor chip 10 and the conductive member 23.

[0043] Furthermore, in this embodiment, the thin film 51 is provided on the surface of portion 23b of the conductive member 23 from the beginning of the linearly extending region to the middle of the linearly extending region. In addition, the thin film 51 is not provided on the surface of portion 23c of the conductive member 23. This reduces the contact area between the resin constituting the resin member 40 and the thin film 51. Since the adhesion between the thin film 51 and the resin is inferior to the adhesion between the copper constituting the conductive member 23 and the resin, reducing the contact area between the thin film 51 and the resin can suppress the decrease in adhesion between the conductive member 23 and the resin. This reduces the occurrence of delamination between the conductive member 23 and the resin, thereby improving the reliability of the semiconductor device.

[0044] Furthermore, if there is no problem with the adhesion between the conductive member 23 and the resin, the thin film 51 may be provided from the beginning to the end of the linearly extending surface of portion 23b of the conductive member 23. In addition, the thin film 51 may also be provided on the surface of portion 23c of the conductive member 23.

[0045] 2. Second Embodiment Next, a semiconductor device of the second embodiment will be described. In the second embodiment, the thin film 51 is provided in a region extending linearly from the bent portion between portion 23a and portion 23b of the conductive member 23 to portion 23b. The second embodiment will mainly be described in terms of differences from the first embodiment. Other configurations that are not described are the same as those of the first embodiment.

[0046] Referring to Figure 6, the connection structure between the semiconductor chip 10 and the conductive member 23 in the second embodiment will be described. Figure 6 is an enlarged view of part A in Figure 3, and is a cross-sectional view showing the connection structure between the source electrode 10s of the semiconductor chip 10 and the conductive member 23.

[0047] A connecting member 32 is provided between the source electrode 10s of the semiconductor chip 10 and portion 23a of the conductive member 23. A thin film 51 is provided on the lower surface of portion 23b of the conductive member 23, that is, on the surface of portion 23b in the X direction (or -Z direction).

[0048] A bent portion (or curved portion) 23ab is provided between (or at the boundary between) portion 23a and portion 23b of the conductive member 23. The bent portion 23ab is a region (or surface) provided in a curved shape between portion 23a and portion 23b.

[0049] The thin film 51 is positioned on the linearly extending surface (or region) of the conductive member 23 from the bent portion 23ab between portion 23a and portion 23b. That is, the thin film 51 is positioned on a portion of the bent portion 23ab between portion 23a and portion 23b, and on the linearly extending surface of portion 23b. The thin film 51 is positioned from the bent portion 23ab to partway along the linearly extending surface of portion 23b. The thin film 51 may also be positioned from the bent portion 23ab to the end of the linearly extending surface of portion 23b, i.e., to a position where it reaches portion 23c.

[0050] In the second embodiment, the thin film 51 is positioned on a portion of the bent portion 23ab between portion 23a and portion 23b, and on the linearly extending surface of portion 23b. Therefore, the amount of upward movement of the connecting member (e.g., solder) 32 to portion 23b can be limited compared to the first embodiment, and the size of the fillet formed at the end of portion 23a can be controlled. Other effects of the second embodiment are the same as those of the first embodiment.

[0051] 3. Third Embodiment Next, a semiconductor device of the third embodiment will be described. In the third embodiment, the thin film 51 is provided only on the bent portion 23ab between portion 23b and portion 23c of the conductive member 23. The third embodiment will mainly be described in terms of differences from the first embodiment. Other configurations that are not described are the same as those of the first embodiment.

[0052] Referring to Figure 7, the connection structure between the semiconductor chip 10 and the conductive member 23 in the third embodiment will be described. Figure 7 is an enlarged view of part A in Figure 3, and is a cross-sectional view showing the connection structure between the source electrode 10s of the semiconductor chip 10 and the conductive member 23.

[0053] The thin film 51 is positioned only on the surface of the bent portion 23ab between portion 23a and portion 23b of the conductive member 23, and not on the linearly extending surface of portion 23b.

[0054] In the third embodiment, the area in which the thin film 51 is placed is narrower than in the first and second embodiments. However, even with this configuration, the amount of creep of the connecting member (e.g., solder) 32 can be limited, and the size of the fillet formed at the end of portion 23a can be controlled.

[0055] Furthermore, in the third embodiment, the contact area between the resin constituting the resin member 40 and the thin film 51 can be reduced compared to the first and second embodiments. This further suppresses the decrease in adhesion between the conductive member 23 and the resin. Other effects of the third embodiment are the same as those of the first embodiment.

[0056] In the first to third embodiments described above, examples were given in which the semiconductor device constitutes a MOS-type field-effect transistor (i.e., a MOSFET). However, the semiconductor device may also constitute other switching elements, such as an IGBT (insulated gate bipolar transistor). When the semiconductor device constitutes an IGBT, the source corresponds to the emitter and the drain corresponds to the collector.

[0057] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0058] 1... Semiconductor device, 10... Semiconductor chip, 10a... Semiconductor layer, 10d... Drain electrode, 10g... Gate electrode, 10s... Source electrode, 21... Conductive member, 21a... Base part, 21b... Protrusion, 22... Conductive member, 23... Conductive member, 23a... Part, 23b... Part, 23c... Part, 23d... Part, 24... Conductive member, 25... Conductive member, 31... Connecting member, 32... Connecting member, 32f... Fillet, 33... Connecting member, 40... Resin member, 51... Thin film.

Claims

1. First conductive member and The second conductive member and A semiconductor chip provided between the first conductive member and the second conductive member, A first connecting member provided between the semiconductor chip and the second conductive member, A thin film is provided on the second conductive member, which contains a material different from that of the first connecting member, It is equipped with, The second conductive member has a first plate portion, a second plate portion, and a third plate portion, The first plate portion extends in a first direction along the first surface of the semiconductor chip and is connected to the semiconductor chip via the first connecting member. The second plate portion extends diagonally from the first plate portion with respect to the first direction, The third plate portion extends from the second plate portion in the first direction, The thin film is arranged on the surface of the second plate portion that is continuous with the surface on which the first connecting member is provided. Semiconductor equipment.

2. The thin film is in contact with the first connecting member. The semiconductor device according to claim 1.

3. The second conductive member is, A bent portion is provided between the first plate portion and the second plate portion. The thin film is arranged on the surface of the bent portion. The semiconductor device according to claim 1.

4. The bent portion is a region provided in a curved shape between the first plate portion and the second plate portion. The semiconductor device according to claim 3.

5. The second plate portion of the second conductive member has a surface that extends in a straight line, The thin film is arranged on the linearly extending surface, The semiconductor device according to claim 1.

6. The thin film is arranged from the beginning to partway along the linearly extending surface. The semiconductor device according to claim 5.

7. The thin film is arranged from the beginning to the end of the linearly extending surface. The semiconductor device according to claim 5.

8. A third conductive member provided at a distance from the first conductive member, The second connecting member and Furthermore, it is equipped with, The second conductive member has a fourth plate portion, The fourth plate portion extends from the third plate portion in a second direction intersecting the first direction, and further extends in the first direction, The second connecting member is provided between the third conductive member and the fourth plate portion. The semiconductor device according to claim 1.

9. The thin film comprises a material different from that of the second conductive member. The semiconductor device according to claim 1.

10. The thin film contains either nickel or aluminum. The semiconductor device according to claim 1.

11. The thin film includes a metal oxide film. The semiconductor device according to claim 1.

12. The aforementioned metal oxide film contains one of copper oxide, nickel oxide, or aluminum oxide. The semiconductor device according to claim 11.

13. The thin film includes an organic film. The semiconductor device according to claim 1.

14. The first connecting member includes solder. The semiconductor device according to claim 1.

15. The second conductive member contains copper. The semiconductor device according to claim 1.

16. The semiconductor chip includes a MOS-type field-effect transistor. The semiconductor device according to claim 1.

17. The aforementioned semiconductor chip includes an insulated gate bipolar transistor (IGBT), The semiconductor device according to claim 1.

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