JP2008153464A - Semiconductor device - Google Patents

Abstract

A support electrode is fitted into a mounting hole of a heat radiating member without generating mechanical stress in a semiconductor element, and the support electrode is securely held in the mounting hole even when the mounting hole of the heat radiating member expands. .
In a semiconductor device (10) according to the present invention, heat is released by pressing a flange (11d) of a bottom wall (11) against an inner inclined surface (22b) of a mounting hole (22) by a fixing member (31). Since the support electrode (1) is fixed in the mounting hole (22) of the body (21), the pressing force acting radially inward by the fixing member (31) is almost the bottom wall (11) of the support electrode (1). Does not participate. For this reason, when the semiconductor device (10) is fitted into the mounting hole (22) of the radiator (21), mechanical stress is hardly generated in the semiconductor element (2). Also, since the flange (11d) is pressed against the inner inclined surface (22b) of the mounting hole (22) by the fixing member (31), the support electrode (1) is mounted even if the mounting hole (22) expands due to heating. It can be securely held in the hole (22).
[Selection] Figure 1

Description

  The present invention relates to a semiconductor device in which a support electrode can be fitted into a mounting hole of a radiator without generating mechanical stress in a semiconductor element when attached to the radiator.

  A press-fit diode device that press-fits a support electrode to which a semiconductor element is fixed into a mounting hole of a radiator is known. For example, a press-fit diode device disclosed in Patent Document 1 below includes a bottom wall (11) and a cylindrical side wall (12) formed on the outer periphery of the bottom wall (11) as shown in FIG. One of the support electrode (1) forming the dish-shaped recess (14), the semiconductor chip (semiconductor element) (2) disposed in the recess (14) of the support electrode (1), and one of the semiconductor chips (2) A lead electrode (3) fixed to the electrode surface (2c), and a resin cover (4) filled in the recess (14) and covering a part of the semiconductor chip (2) and the lead electrode (3); Is provided. The lead electrode (3) includes a header (13) fixed to one electrode surface (2c) of the semiconductor chip (2) by a brazing material (6) such as solder, and a shaft portion extending upward from the header (13). (17) In the diode device (30) shown in FIG. 8, the inner bottom surface (14b) forming the recess (14) of the support electrode (1) is formed integrally with the bottom wall (11) and protruding from the inner bottom surface (14b). It has a support part (7). The other electrode surface (2b) of the semiconductor chip (2) is fixed to the support portion (7) with a brazing material (6), and electrically connects the semiconductor chip (2) and the support electrode (1).

  The support electrode (1) is formed of a metal with high heat dissipation such as copper, and heat generated by current flowing through the semiconductor chip (2) is released to the outside through the support electrode (1). That is, the support electrode (1) acts as an electrode for the semiconductor chip (2) and also acts as a heat sink. For example, when a large reverse surge voltage is applied to the semiconductor chip (2), if the support electrode (1) does not have a sufficient heat capacity, a sufficient amount of heat is not discharged through the support electrode (1). The chip (2) is heated, and the electrical characteristics of the semiconductor chip (2) may be deteriorated.

  The diode device (30) shown in FIG. 6 is applied to an output rectifier diode of an automotive alternator (alternator), for example. As shown in FIG. 9, a diode device is provided by a pressing jig (20) toward a mounting hole (22) formed in the radiator (21) of the AC generator with an inner diameter smaller than the outer diameter of the side wall (12). By pressing the bottom surface (1c) of the support electrode (1) of (30), the support electrode (1) is press-fitted into the mounting hole (22), and the diode device (30) is mounted on the radiator (21). Retained in the hole (22).

JP 2002-261210 A

  However, in the diode device of Patent Document 1 described above, when the support electrode (1) is forcibly press-fitted into the mounting hole (22) of the radiator (21), the support electrode is formed by the inner wall that forms the mounting hole (22). Since the outer peripheral surface (1a) of (1) is pressed radially inward and compressive force (P) or bending stress is transmitted from the side wall (12) to the center of the bottom wall (11), the semiconductor chip (2 ) May cause mechanical stress to break the semiconductor chip (2), which may deteriorate the electrical characteristics.

  Accordingly, an object of the present invention is to provide a semiconductor device in which a support electrode can be fitted into a mounting hole of a heat radiating body without generating mechanical stress in the semiconductor element.

  The semiconductor device (10) of the present invention includes a support electrode (1) that forms a dish-shaped recess (14) by a bottom wall (11) and a cylindrical side wall (12) formed on the outer periphery of the bottom wall (11). ), The semiconductor element (2) disposed on the bottom wall (11) in the recess (14), the lead electrode (3) fixed to the semiconductor element (2), and the recess (14) filled. And a resin coating (4) that covers a part of the semiconductor element (2) and the lead electrode (3). In this semiconductor device (10), the bottom wall (11) of the support electrode (1) includes an outer inclined surface (11c) formed in a tapered cone shape toward the bottom surface (11a) of the bottom wall (11), The outer inclined surface (11c) protrudes radially outward from the side wall (12) at the connection portion with the side wall (12) to form a flange (11d) having the maximum diameter of the bottom wall (11), and is a metal radiator. When the support electrode (1) is fitted into the mounting hole (22) formed in (21), the outer inclined surface (11c) is an inner inclined surface that forms the mounting hole (22) of the radiator (21) ( 22b), and is fixed between the inner wall (22d) and the side wall (12) of the large diameter portion (22a) formed above the inner inclined surface (22b) of the mounting hole (22). By (31), the flange (11d) of the bottom wall (11) is pressed against the inner inclined surface (22b) of the mounting hole (22).

  The supporting member is inserted into the mounting hole (22) of the radiator (21) by pressing the flange (11d) of the bottom wall (11) against the inner inclined surface (22b) of the mounting hole (22) by the fixing member (31). Since (1) is fixed, almost no pressing force acting radially inward by the fixing member (31) is applied to the bottom wall (11) of the support electrode (1). For this reason, when the semiconductor device (10) is fitted into the mounting hole (22) of the radiator (21), mechanical stress is hardly generated in the semiconductor element (2). Further, since the fixing member (31) presses the flange (11d) of the support electrode (1) against the inner inclined surface (22b) of the mounting hole (22) of the radiator (21), the support electrode (1) is Compared with the conventional structure in which the support electrode is pressed into the mounting hole (22) of (21) and the support electrode is fixed in the mounting hole using friction, the support electrode (1) is inserted into the mounting hole (22). It can be held securely.

  In the present invention, since the support electrode can be fitted into the mounting hole of the heat sink without generating mechanical stress in the semiconductor element at the time of mounting to the heat sink, a highly reliable semiconductor that does not deteriorate the electrical characteristics of the semiconductor element. An apparatus can be provided.

  1 to 7 show an embodiment of a semiconductor device according to the present invention applied to an output rectifier diode of an automotive alternator. However, in FIGS. 1-7, the part substantially the same as the location shown in FIG.8 and FIG.9 is attached | subjected the same code | symbol, and the description is abbreviate | omitted.

  As shown in FIG. 1, the diode device (10) of the present embodiment includes a bottom wall (11) and a cylindrical side wall (12) formed so as to protrude upward from the outer peripheral portion of the bottom wall (11). Fixed to the support electrode (1) forming the concave recess (14) and the support portion (7) formed on the bottom wall (11) in the recess (14) by the brazing material (6) such as solder. The semiconductor chip (2), the lead electrode (3) having the header (13) and the shaft portion (17) fixed to the upper surface of the semiconductor chip (2) by the brazing material (6), and the recess (14) are filled. The semiconductor chip (2) and the resin coating (4) covering the header (13) of the lead electrode (3) and a part of the shaft portion (17) are provided. The support electrode (1) is made of, for example, a material having high thermal conductivity and high conductivity (for example, copper or copper alloy), and is formed in a dish shape by a known press working or the like. The bottom wall (11) of the support electrode (1) includes an outer inclined surface (11c) formed in a tapered cone shape from the upper surface (11b) toward the bottom surface (11a). The outer inclined surface (11c) protrudes radially outward from the side wall (12) at the connection portion with the side wall (12) to form a flange (11d) having the maximum diameter of the bottom wall (11). That is, as viewed in a plan view, the outer inclined surface (11c) extends outward from the side wall (12), and a flange (11d) is formed in an annular shape on the outer periphery of the side wall (12). The side wall (12) is formed higher than the upper surface of the semiconductor chip (2). The semiconductor chip (2) is formed, for example, by forming a semiconductor crystal such as silicon in a disc shape or a thin plate shape, and constitutes a known PN junction diode. The lead electrode (3) is formed of, for example, copper or a copper alloy, and the header (13) is formed in a columnar shape, a disc shape, or a conical shape, and a rod-shaped shaft portion (17 ) Is formed by extending upward. The support electrode (1) and the lead electrode (3) made of a metal having high thermal conductivity absorb heat generated in the semiconductor chip (2) and release it to the outside of the diode device (10). The resin coating (4) is formed of a resin having high heat resistance such as an epoxy resin or a silicone resin. Other configurations are substantially the same as those of the conventional diode device (30) shown in FIG.

  When the diode device (10) having the above configuration is fixed in the mounting hole (22) formed in the radiator (21) of the automotive alternator made of aluminum or aluminum alloy, the support electrode (1) When fitted into the mounting hole (22) of the radiator (21), the outer inclined surface (11c) of the support electrode (1) is a conical inner slope that forms the mounting hole (22) of the radiator (21). It contacts the surface (22b). In the present embodiment, the bottom surface (11a) of the support electrode (1) protrudes from the bottom surface (21a) of the radiator (21), but the bottom surface (11a) of the support electrode (1) and the bottom surface of the radiator (21a) (21a) may be flush with each other, and the bottom surface (11a) of the support electrode (1) may be recessed from the bottom surface (21a) of the radiator (21a). Next, as shown in FIGS. 2 and 3, a cylindrical large diameter formed above the inner inclined surface (22b) of the mounting hole (22) of the radiator (21) via a step portion (22c). An annular fixing member (31) having an outer diameter larger than the inner diameter of the large diameter portion (22a) is press-fitted between the inner wall (22d) and the side wall (12) of the portion (22a) with a press machine or the like. It adheres by. Thereby, the flange (11d) of the bottom wall (11) of the support electrode (1) is pressed against the inner inclined surface (22b) of the mounting hole (22) of the radiator (21), and the diode device (10) The support electrode (1) is fixed in the mounting hole (22) of the heat radiating body (21), and the support electrode (1) and the heat radiating body (21) are brought into contact with each other to obtain good thermal conductivity. The fixing member (31) is made of a metal having the same elastic modulus as that of the radiator (21) or a plate material made of a soft metal having a lower elastic modulus than that of the support electrode (1). It is formed by punching or the like. By forming the fixing member (31) from metal, heat generated in the semiconductor chip (2) can be radiated through the fixing member (31). Further, since the support electrode (1) is fixed to the heat radiating body (21) by fitting the fixing member (31), the diode device (10) can be connected to the heat radiating body (2) without generating mechanical stress on the semiconductor chip (2). 21) can be fitted into the mounting hole (22).

  In the diode device (10) of the present embodiment, the flange (11d) of the bottom wall (11) of the support electrode (1) is attached to the mounting hole (22) of the radiator (21) by the annular fixing member (31). Since the supporting electrode (1) is fixed to the mounting hole (22) by pressing against the inner inclined surface (22b), the pressing force acting radially inward by the fixing member (31) is reduced to the bottom wall (11 ) Does not participate. That is, the support electrode (1) is not pressed radially inward by the heat radiating body (21). For this reason, when the diode device (10) is fitted into the mounting hole (22) of the radiator (21), mechanical stress is hardly generated in the semiconductor chip (2). When fixing the fixing member (31) between the large diameter portion (22a) formed in the mounting hole (22) of the radiator (21) and the side wall (12) of the support electrode (1), the fixing member ( In order to make it difficult for the pressing force applied from 31) to be applied to the semiconductor chip (2) through the side wall (12), it is desirable to form the side wall (12) to a thickness that elastically deforms to some extent radially inward. Further, since the fixing member (31) presses the flange (11d) of the support electrode (1) against the inner inclined surface (22b) of the mounting hole (22) of the radiator (21), the support electrode (1) is Compared with the conventional diode device (30) shown in FIG. 8 in which the support electrode (1) is fixed in the mounting hole (22) using the friction generated when it is press-fitted into the mounting hole (22) of (21). Even if the mounting hole (22) of the radiator (21) expands and expands due to heat generated during the operation of the diode device (10), the support electrode (1) remains in the mounting hole (22). The diode device (10) can be securely held and can be prevented from falling off the radiator (21). Furthermore, when the fixing member (31) is formed of the same kind of metal material as that of the heat radiating body (21), the above-described effects can be satisfactorily exhibited.

  Embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made. For example, in the above-described embodiment, the annular fixing member (31) is formed of the same kind of metal as the heat dissipating body (21) or the elastic coefficient lower than that of the support electrode (1), that is, a soft metal. When the heat generation amount of the tip (2) is small or the heat capacity of the support electrode (1) is sufficiently large, as shown in FIG. 4, the inner wall (22d) of the large diameter portion (22a) of the mounting hole (22) A resin-made fixing member (41) formed in an annular shape with a predetermined dimension may be press-fitted between the side wall (12) and fixed. Instead of press-fitting the resin fixing member (41), the resin in a fluid state between the inner wall (22d) and the side wall (12) of the large-diameter portion (22a) of the mounting hole (22) of the radiator (21) The resin fixing member (41) may be formed by pouring and curing. In the above embodiment, the inner wall of the annular fixing member (31) is in contact with the side wall (12) of the support electrode (1). However, as shown in FIG. The side wall (12) of the electrode (1) may not be in contact. In this case, an annular fixing member having an outer diameter larger than the inner diameter of the large-diameter portion (22a) of the radiator (21) and an inner diameter larger than the outer diameter of the side wall (12) of the support electrode (1). Use (31). When the fixing member (31) is press-fitted and fixed into the inner wall (22d) of the large-diameter portion (22a) of the radiator (21), the bottom wall of the support electrode (1) is fixed by the fixing member (31). 11) The flange (11d) is only pressed against the inner inclined surface (22b) of the mounting hole (22) of the radiator (21), and the pressing force acting radially inward through the side wall (12) is supported. It is possible to completely prevent the electrode (1) from being applied. Further, as shown in FIG. 6, on the outer peripheral surface of the internal thread (22e) formed on the inner wall (22d) of the large diameter portion (22a) of the mounting hole (22) of the radiator (21) and the fixing member (51). The fixing member (51) is fixed between the inner wall (22d) and the side wall (12) of the large-diameter portion (22a) of the mounting hole (22) by screwing the formed male screw (51a). May be. Further, the outer peripheral surface of the fixing member (31) is subjected to a known knurling process so that the outer wall of the large-diameter portion (22a) of the mounting hole (22) of the radiator (21) and the outer periphery of the fixing member (31). The surface may be further adhered. In addition, a gap formed between the outer inclined surface (11c) of the support electrode (1) and the inner inclined surface (22b) of the mounting hole (22) of the radiator (21) when the fixing member (31) is press-fitted is soldered or the like. It may be filled with brazing material. In this case, there is an advantage that the thermal conductivity and electrical connection between the support electrode (1) and the radiator (21) can be obtained stably. Furthermore, as shown in FIG. 7, the present invention can also be applied to a diode device (40) having a structure in which a semiconductor chip (2) is fixed on a flat support electrode (1). The shapes and structures of the semiconductor chip (2), the lead electrode (3), and the resin coating (4) shown in the figure do not limit the present invention.

  The present invention can be favorably applied to a diode device that requires high heat dissipation, such as an output rectifier diode used in an automotive alternator.

Sectional drawing which shows one Embodiment which applied the semiconductor device by this invention to the output rectifier diode of the alternating current generator for motor vehicles Sectional drawing which shows the state which attached the fixing member Plan view of the diode device of FIG. Sectional drawing which shows the 1st modified embodiment of the diode apparatus by this invention Sectional drawing which shows 2nd modified embodiment of the diode apparatus by this invention Sectional drawing which shows the 3rd modification embodiment of the diode apparatus by this invention Sectional drawing which shows other embodiment of the diode apparatus by this invention. Sectional view showing a conventional press-fit diode device 8 is a cross-sectional view of the diode device shown in FIG.

Explanation of symbols

  (1) ・ ・ Support electrode, (1a) ・ ・ Outer peripheral surface, (1b) ・ ・ Top surface, (1c) ・ ・ Bottom surface, (1d) ・ ・ Rim, (1e) ・ ・ Outer inclined surface, (2)・ ・ Semiconductor chip (semiconductor element), (2b) ・ ・ Other electrode surface, (2c) ・ ・ One electrode surface, (3) ・ ・ Lead electrode, (4) ・ ・ Resin coating, (6) ・· Brazing material, (7) · · Support, (10,40) · · Diode device, (11) · · Bottom wall, (11a) · · Bottom, (11b) · · Top surface, (11c) · · Outside Inclined surface, (11d) ・ ・ Flange, (12) ・ ・ Side wall, (13) ・ ・ Header, (14) ・ ・ Recess, (14b) ・ ・ Inner bottom, (17) ・ ・ Shaft, (21)・ ・ Heat radiator, (21a) ・ ・ Bottom, (22) ・ ・ Mounting hole, (22a) ・ ・ Large diameter part, (22b) ・ ・ Inner inclined surface, (22c) ・ ・ Step, (22d) ・・ Inner wall, (22e) ・ ・ Female screw, (30) ・ ・ Conventional diode device (31,51) ・ ・ Fixing member, (41) ・ ・ Resin fixing member, (51a) ・ ・ Male screw,

Claims (5)

A support electrode forming a dish-shaped recess by a bottom wall and a cylindrical side wall formed on the outer periphery of the bottom wall, a semiconductor element disposed on the bottom wall in the recess, and fixed to the semiconductor element A lead electrode, and a resin coating that fills the recess and covers a part of the semiconductor element and the lead electrode,
The bottom wall of the support electrode includes an outer inclined surface formed in a conical shape tapered toward the bottom surface of the bottom wall;
The outer inclined surface forms a flange having a maximum diameter of the bottom wall projecting radially outward from the side wall at a connection portion with the side wall;
When the support electrode is fitted in a mounting hole formed in a metal radiator, the outer inclined surface is in contact with an inner inclined surface that forms the mounting hole of the radiator,
The flange of the bottom wall is pressed against the inner inclined surface of the mounting hole by an annular fixing member fixed between the inner wall of the large diameter portion formed above the inner inclined surface of the mounting hole and the side wall. A semiconductor device comprising:   The fixing member is press-fitted into the inner wall of the large-diameter portion formed in the mounting hole, or the fixing member is fixed by screws formed on the inner wall of the large-diameter portion and the outer peripheral surface of the fixing member. Item 14. The semiconductor device according to Item 1.   The semiconductor device according to claim 1, wherein the fixing member is formed of a metal that is the same type as the heat radiating body or has a lower elastic coefficient than the support electrode.   The side wall is elastically deformed radially inward when the fixing member is fixed between the large-diameter portion formed in the mounting hole of the radiator and the side wall of the support electrode. 2. A semiconductor device according to item 1. A plate-like support electrode having a semiconductor element fixed on the upper surface, a lead electrode fixed to the semiconductor element, and a resin coating covering a part of the semiconductor element and the lead electrode,
The peripheral edge portion of the support electrode includes an outer inclined surface formed in a conical shape tapered toward the bottom surface of the support electrode,
When the support electrode is fitted in a mounting hole formed in a metal radiator, the outer inclined surface is in contact with an inner inclined surface that forms the mounting hole of the radiator,
The peripheral portion of the support electrode is pressed against the inner inclined surface of the mounting hole by an annular fixing member press-fitted into the inner wall of the large diameter portion formed above the inner inclined surface of the mounting hole. A semiconductor device.

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