This application is based on and incorporates herein by reference Japanese Patent Application No. 2002-84434 filed on Mar. 26, 2003.
The present invention relates to a semiconductor device used in a three-phase inverter circuit or the like.
A semiconductor power element used in an inverter circuit for driving an automobile motor is available as a power element package integrated with a mold resin, where a power element is sandwiched between heat sink plates of radiating members (refer to JP-A-2001-156225 or USP-2003/0132530 A1). The power element includes an IGBT (Insulated Gate Bipolar Transistor) as a typical power element. The power element of the IGBT is sandwiched between the heat sink plates while an emitter or collector of the power element is connected using solder with the heat sink plate directly or via a spacer. Here, the heat sink plate functions as a path of a large electric current. A gate (control electrode) of the power element is electrically connected with a lead terminal for control signals that is outwardly protruding from the mold resin via a bonding wire. The power element is thus constructed as a power element package. A plurality of the power element packages is assembled to constitute a module of inverter circuit.
In addition, increase of the dimensions of the heat sink plate is proposed to further reduce thermal resistance of the power element package. This proposal involves problem in connection structure where a power element is connected using the boding wire, as explained above, with a lead terminal for control signals to the power element. Here, to maintain connection reliability a wire length is required to be at most 10 mm. The wire length of more than 10 mm potentially involves, during the resin molding, mutual contact between the adjoining wires or breakage of the wire. The connection structure using the bonding wire is therefore improper for increasing the dimensions of the heat sink.
It is an object of the present invention to a resin molded semiconductor device suitable for increased dimensions of a heat sink.
To achieve the above object, a semiconductor device is provided with the following. An element of a semiconductor switching element is provided such that the element includes two of a first and second surfaces. A first electrode is exposed on the first surface; a second electrode is exposed on the second surface; and a control electrode is exposed on a control-electrode-exposing surface that is one of the first and second surfaces. Two radiating members are provided such that the element is disposed between the two radiating members. The two radiating members are electrically connected with the first and second electrodes, respectively. Each of the two radiating members has an inward surface that is closer to the element than the other surface. A mold resin member fills a space between the two radiating members. An insulating layer is formed on at least one of the inward surfaces of the two radiating members. A conductive layer is formed on the insulating layer and electrically connected with the control electrode and an input portion protruding from the mold resin member. Further, one of the first and second electrodes is electrically connected with a non-insulating portion of the inward surface where the insulating layer is formed, wherein no insulating layer is formed on the non-insulating portion.
This structure enables a semiconductor switching element of a semiconductor package to be cooled from both top and bottom surfaces. In particular, in this structure, an insulating layer is formed on an inward surface of a radiating member, and a conductive layer is then formed on the insulating layer. This conductive layer functions as an intermediate wiring that exists between the semiconductor chip and a signal terminal as a lead terminal that is outwardly protruding from a mold resin member. This structure is useful in a case that the radiating member becomes large and a distance between a control electrode of the semiconductor switching element and the peripheral surface of the radiating member becomes long. Namely, by appropriately designing the conductive layer, electrical connection is easily secured between the semiconductor chip and the signal terminal.
The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
The present invention is directed to a power element package as a semiconductor device. Referring to
The power element package 100 includes a semiconductor chip 7, radiating members 1, 4, a mold resin member 11, a lead terminal 8 for control signals, and lead terminals 9, 10 for large electric current. The semiconductor chip 7 is electrically connected with the radiating members 1, 4 through solder connection members 5, 6. On a heat accepting surface 1p of the radiating member 1, an insulating layer 2 and a conductive layer 3 are disposed. The lead terminal 8 for control signals is electrically connected with a gate 7g of the semiconductor chip 7 through the conductive layer 3.
As shown in an enlarged main part in
As explained above, the pair of radiating members 1, 4 is disposed as sandwiching the semiconductor 7. The emitter 7e of the semiconductor 7 is electrically connected with the radiating member 1 of the pair through the solder connection member 6. By contrast, the collector 7c is electrically connected with the other radiating member 4 through the solder connection member 5. With respect to the solder connection members 5, 6, their solder amounts are controlled such that the solder connection members coat the entire surfaces of the collector 7c and emitter 7e. The solder as a conductive connection member can be replaced with a known Ag brazing material.
The radiating members 1, 4 have compressed or plate shapes; each has an inward heat accepting surface 1p, 4p and an outward heat radiating surface 1q, 4q, both of which are substantially plane and parallel with each other. The dimensions of the heat accepting surfaces 1p, 4p and radiating surfaces 1q, 4q are much larger than those of the surfaces of the semiconductor chip 7. This increases cooling capability to thereby control the thermal resistance of the power element package 100 for being small. The radiating member 1, 4 is favorably formed of a pure metal selected from a group of Cu, W, Mo, and Al or an alloy that is mainly composed of the metals selected from the group from the view point of thermal and electrical conductivity.
Further, a mold resin member 11 is formed so as to cover or coat the peripheral sides of the semiconductor chip 7 and filling the space formed by the radiating members 1, 4. The mold resin member 11 is formed of, e.g., an epoxy resin. The radiating member 1 is integrated with the lead terminal 9 for large electric current outwardly protruding from the mold resin member 11, while the radiating member 4 is integrated with the lead terminal 10 for large electric current outwardly protruding from the mold resin member 11, as shown in
The semiconductor chip 7 is disposed between the radiating members approximately in a center position in a lateral direction (rightward-leftward direction in
In the present invention, the conductive layer 3 functions as a relaying wiring between the gate 7g and the lead terminal 8; the conductive layer 3 is formed on the heat accepting member 1p of the radiating member 1 via the insulating layer 2. The lead terminal 8 for control signals is a strip-shaped or linear member of a highly conductive metal material such as copper or copper alloy.
As shown in
The relative position of the semiconductor chip 7 and the insulating layer 2 that is formed on the radiating member 1 is shown in
The insulating layer 2 is formed of a heat resisting resin preferably having a higher heat resisting temperature (thermal decomposition start temperature) than the reachable temperature (approximately 260° C. in the typical lead flow soldering) in the reflow soldering. This is required in the view of preventing insulation deterioration during the reflow soldering or aged insulation deterioration. In detail, a polyamide resin is a suitable material for the insulating layer 2. The thickness of the insulating layer 2 needs to be greater than 10 μm for securing the insulation. The insulating layer 2 is formed by attaching a resin film on the heat accepting surface 1p of the radiating member 1, the resin film where the opening 2p is previously formed.
The conductive layer 3 is favorably formed by pattern wiring of high conductive material such as copper or copper alloy. The pattern wiring is relatively easily formed on the insulating layer, so that manufacturing costs can be reduced. The thickness of the conductive layer 3 needs to be greater than 20 μm for securing the appropriate connection with the soldering. The conductive layer 3 is formed by attaching a copper foil on the insulating layer 2 and then pattern etching the cupper foil. Otherwise, it can be also formed by pattern metal plating.
The thickness of the soldering connection member 6 is controlled for being 80 to 150 μm posterior to the reflow soldering. When the thickness exceeds 150 μm, the control of the solder amount becomes difficult, which may involve a short-circuit between the gate 7g and emitter 7e. Further, the semiconductor chip 7 is potentially fixed such that the semiconductor chip 7 inclines to a large extent against both the radiating members 1, 4, so that the thickness of the soldering connection member 6 is favorably from 80 to 150 μm, as assumed from
As shown in
As explained above, in the power element package 100, eliminating the bonding wire results in decrease of space in a vertical direction in
Further, when the insulating layer 2 and the conductive layer 3 are provided, a component 14 such as an IC, a resistor, or a capacitor can be also disposed on the insulating layer 2, as shown in a dotted line in
As shown in
The power element package 101 includes a pair of semiconductor chips 7x, 7y having circuits equivalent to each other; individual radiating members 21, 22 corresponding to the semiconductor chips 7x, 7y, respectively; a radiating member 20 used in common for both the semiconductor chips 7x, 7y; a mold resin member 23 that covers the peripheral sides of the chips 7x, 7y and fills the space formed by the radiating members 20, 21, 22. The radiating members 21, 22 can be formed of the same member. The semiconductor chip 7x and the semiconductor chip 7y are disposed such that both are apart from each other horizontally in
The semiconductor chip 7x disposed between the radiating members 20, 21 are directly connected with the radiating members 20, 21 using the solder connection members 24, 25. By contrast, the semiconductor chip 7y disposed between the radiating members 20, 22 are directly connected with the radiating members 20, 22 using the solder connection members 28, 29. Here, the semiconductor chip 7y is disposed so that the front and rear surfaces of the semiconductor chip 7y is reverse to those of the semiconductor chip 7x. Namely, a top and bottom relationship with respect to the front and rear surfaces (or the first and second surfaces) of the semiconductor chip 7x is reverse to that of the semiconductor chip 7y. Therefore, the emitter of the semiconductor chip 7x is electrically connected with the collector of the semiconductor 7y via the radiating member 20, so that two IGBTs are serially connected. The forming structure of the gate, emitter, and collector are equivalent to that in
As shown in
The common use radiating member 20 has an inward heat accepting surface 20p and an outward radiating surface 20q. On the heat accepting surface 20p, an insulating layer 36 and conductive layer 38 are disposed. The insulating layer 36 has openings 36s, 36t within which solder connection members 25, 29 are formed. On the surface facing the radiating member 20, the semiconductor chip 7x has a gate whose exposed gate area is overlapped and electrically connected with the conductive layer 38 using a solder connection member 27.
The radiating members 21, 22 have inward heat accepting surfaces 21p, 22p and outward radiating surfaces 21q, 22q, respectively. On the heat accepting surface 22p of the radiating member 22, an insulating layer 37 and conductive layer 39 are disposed. The insulating layer 37 has an opening 37p within which a solder connection member 28 is formed. On the surface connected with the radiating member 22, the semiconductor chip 7y has a gate whose exposed gate area is overlapped and electrically connected with the conductive layer 39 using a solder connection member 30.
The above conductive layers 38, 39 are connected with ends of the control signal lead terminals 34, 35 via solder connection members 26, 31, respectively; the other ends of the control signal lead terminals 34, 35 outwardly protrude from the mold resin member 23, respectively. Each of the radiating members 20, 21, 22 is integrated with a large current lead terminal (not shown).
As shown in
On its surface reverse to the surface where the gate is exposed, the semiconductor chip 7 is directly connected with the radiating member 50 via a solder connection member 41. On the surface where the gate is exposed, the semiconductor chip 7 is connected with the radiating member 51 via a spacer 57 and solder connection members 46, 47. The solder connection member 46 connects the semiconductor chip 7 and the spacer 57, while the solder connection member 47 connects the spacer 57 and the radiating member 51.
The radiating members 50, 51 have inward heat accepting surfaces 50p, 51p and outward radiating surfaces 50q, 51q, respectively. On the heat accepting surface 50p of the radiating member 50, an insulating layer 55 is disposed. The insulating layer 55 has an opening 55s within which the semiconductor chip can be accommodated. The insulating layer 55 is thereby disposed so that the insulating layer 55 looks surrounding the semiconductor chip 7 in an overhead view from above in
On the insulating layer 55, a conductive layer 56 is formed. The gate 7g of the semiconductor chip 7 (refer to
As shown in
The semiconductor chips 7, 7 are supplied with the control signals through the gates 7g, 7g from the single lead terminal 40 for control signals. In detail, the conductive layer 56 that connects with the lead terminal 40 branches, so that the control signals are supplied to the semiconductor chips 7, 7 whose number (two in this embodiment) is larger than that of the lead terminal 40. Namely, the control signal line branches within the package.
Further, resistors 62, 62 disposed on the conductive layer 56 are used as balance resistors for preventing difference in a switching speed owing to deviation between the semiconductor chips 7, 7 and for stabilizing operation. It is supposed that multiple semiconductor chips 7, 7 are parallelly connected mutually to be integrated as a package. Here, adopting the structure of the present invention where an insulating layer and conductive layer are formed on a radiating member enables resistors 62, 62 to be easily provided. In addition, an emitter 7 Ke shown in
Further, as shown in
A power element package 103 as a fourth embodiment will be explained in comparison with the first embodiment using
A power element package 104 as a fifth embodiment will be explained in comparison with the first embodiment using
A power element package 105 as a sixth embodiment will be explained in comparison with the first embodiment using
A power element package 106 as a sixth embodiment will be explained in comparison with the first embodiment using
A power element package 107 as a sixth embodiment will be explained in comparison with the first embodiment using
It will be obvious to those skilled in the art that various changes may be made in the above-described embodiments of the present invention. However, the scope of the present invention should be determined by the following claims.
Number | Date | Country | Kind |
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2003-084434 | Mar 2003 | JP | national |
Number | Name | Date | Kind |
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6255672 | Yoshioka et al. | Jul 2001 | B1 |
6542365 | Inoue | Apr 2003 | B2 |
6845012 | Ohkouchi | Jan 2005 | B2 |
7027302 | Inoue | Apr 2006 | B2 |
20030132530 | Teshima et al. | Jul 2003 | A1 |
20050040515 | Inoue et al. | Feb 2005 | A1 |
20060120047 | Inoue | Jun 2006 | A1 |
Number | Date | Country |
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A-08-078599 | Mar 1996 | JP |
A-10-79453 | Mar 1998 | JP |
A-2000-174180 | Jun 2000 | JP |
A-2002-164485 | Jun 2002 | JP |
Number | Date | Country | |
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20040195649 A1 | Oct 2004 | US |