JP3215254B2 - High power semiconductor devices - Google Patents

Abstract

PURPOSE:To enhance the lifetime in TFT test by making a groove for fitting a board in the lower part of an enclosure on the inside of the side wall, fitting a board comprising a ceramic board having a recessed cross-section and a metal part formed on the main surface on the opposite side to the recessed side into the groove and providing a bottom cover for the enclosure thereby eliminating the need of a metal heat plate and a soldering material. CONSTITUTION:A ceramic board la having cross-section protruding downward is bonded selectively with a copper plate 1b on the flat surface on the opposite side and a power element 3 is bonded to a predetermined part on the surface of the copper plate 1b through a high melting point solder 2. A terminal holder 6 built in an outer electrode is then bonded to the copper plate 1b. The ceramic board la is fitted, at the peripheral end part, in a groove 8 made in the lower board of a resin enclosure 7 and then the ceramic board 1a is urged downward by means of a stop metal 9 fixed to the upper face part of the groove 8. Furthermore, the board 1 is bonded to the enclosure 7 through an adhesive 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high power semiconductor device equipped with a power element for controlling high power.

[0002]

2. Description of the Related Art A large power semiconductor device (hereinafter, simply referred to as a module) on which a plurality of power elements for controlling a large power is mounted generates a large amount of heat in the power element portion during operation, and this heat is efficiently removed to the outside. Dissipation to the module is an important factor in improving the reliability of the module.

As a conventional module having an envelope structure that satisfies these functions, a module shown in FIG. 11 is generally used.

[0006] In FIG. 11, reference numeral 101 denotes a DBC substrate, and copper plates 103 selectively patterned are formed on both surfaces of a ceramic plate 102. The DBC substrate generates an alloy layer between the ceramic plate 102 and the copper plate 103 and uses the alloy layer as an adhesive. A power element 105 is fixed on the surface of a predetermined portion of the patterned copper plate 103 via a high melting point solder 104.

Also, electrodes are taken out from the upper surface of the power element 105 to the copper plate 103 on the DBC substrate 101 by bonding wires 106. further,
The terminal holder 1 with a built-in external electrode terminal is provided on the copper plate 103 on the upper surface side of the DBC substrate 101 by the low melting point solder 107.
08, and a metal heat sink 109 is fixed to the copper plate 103 on the lower surface side.

[0006] These components are the resin case 1
The resin case 110 is fixed to the metal heat sink 109 with an adhesive 111. Further, the space inside the resin case 110 is filled with a silicone resin gel agent 112 as a lower layer filler and an epoxy resin casting agent 113 as an upper layer filler, and the inside of the resin case 110 is sealed.

[0007]

SUMMARY OF THE INVENTION In the module having the above structure, a reliability life test (TFT test) of the module is performed.
In this case, there is a problem that the low-melting-point solder 107 fixing the DBC substrate 101 and the metal heat sink 109 is fatigued and cracked.

More specifically, in this TFT test, ON / OFF is repeated in a fixed cycle, and the influence of the temperature rise due to the energization of the power element 105 when ON and the cooling effect due to forced cooling when OFF is evaluated. It is a test. When a temperature change is applied to two types of materials having different coefficients of thermal expansion, the two types of materials repeatedly expand and contract in volume according to their own coefficients of thermal expansion.

This phenomenon is basically the same even when two types of materials are bonded via an intermediate such as solder. In this case, the difference between the coefficients of thermal expansion of the two types of materials is determined by the bonding intermediate. The result is that the material accumulates as stress (strain). This accumulated stress causes the material to fatigue. In particular, solder materials are susceptible to fatigue due to thermal energy.

The low-melting point solder 107, which is an intermediate between the conventional DBC substrate 101 and the metal heat sink 109, is located in a path through which heat generated by the power element 105 escapes to the outside of the module, and has another solder (power Since the bonding area is larger than that of the high melting point 104 for fixing the element and the low melting point solder 107) for fixing the terminal holder, it is the most fatigued part in the TFT test.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a high-power semiconductor device having a significantly improved life in a TFT test. Another object is to provide a high-quality high-power semiconductor device with excellent durability.

[0012]

Means for Solving the Problems To achieve the above object, a first aspect of the present invention is a ceramic plate having an inverted convex cross section and a metal formed on a main surface opposite to the convex side of the ceramic plate. And a power element mounted on the surface of the metal member of the substrate.

[0013] In order to achieve the above object, a second aspect of the invention is characterized in that a substrate on which a power element is mounted, a terminal holder electrically connected to the power element, the power element and the terminal holder are provided. An envelope to be casing,
In a high-power semiconductor device in which a resin is filled in a space inside the envelope formed by the envelope and the substrate so as to lead the terminal holder to the outside, a lower portion inside a sidewall of the envelope is provided. A substrate mounting groove, wherein the substrate is mounted in the substrate mounting groove to serve as a bottom cover of the envelope.

Preferably, in the second invention, the substrate is formed to have an inverted convex cross-section by cutting off a lower portion of a peripheral end thereof, and the peripheral end of the substrate is mounted in the substrate mounting groove. To do it.

[0015] Preferably, in the second aspect of the present invention, a holding member for pressing the substrate is provided in the substrate mounting groove.

Preferably, in the second invention, the substrate is composed of the ceramic member having an inverted convex cross section and a metal member formed on a main surface of the ceramic member opposite to the convex surface. The power element is mounted on a surface of a metal member.

Preferably, in the second invention, a metal guide is embedded in a side wall of the envelope so as to be located below the substrate mounting groove.

Preferably, in the second invention, a screw hole for fixing an outer casing is formed in an outer extension of the envelope extending from an outer wall surface of the envelope in a direction opposite to the substrate. I do.

To achieve the above object, a third aspect of the present invention is characterized in that a substrate on which a power element is mounted, a terminal holder electrically connected to the power element, the power element and the terminal holder are provided. An envelope to be casing,
In a high-power semiconductor device in which a resin is filled into a space inside the envelope formed by the envelope and the substrate so as to lead the terminal holder to the outside, the substrate may be a package of the envelope. That is, it is formed integrally with the envelope so as to be a bottom cover.

In order to achieve the above object, a fourth aspect of the invention is characterized by a substrate on which a power element is mounted, a terminal holder electrically connected to the power element, and a casing comprising the power element and the terminal holder. A high-power semiconductor device in which a resin is filled into a space inside the envelope formed by the envelope and the substrate so as to lead the terminal holder to the outside. The substrate is configured to be larger than the envelope so that the envelope is mounted on the upper surface side thereof, and a screw for fixing an external housing is provided on an extension portion extending to the outside from the envelope. A hole has been drilled.

[0021]

According to the construction as described above, according to the present invention, when an envelope is used, the substrate is fixed by the envelope.
Conventionally, it is possible to omit a metal heat radiating plate used for fixing a substrate and a solder material for fixing the heat radiating plate to the substrate.

[0022]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a configuration of a high-power semiconductor device according to a first embodiment of the present invention.

This module has a high thermal conductive substrate 1 composed of a ceramic plate 1a and a copper plate 1b having an inverted convex cross section. On the main surface side of the ceramic plate 1a, that is, on the flat surface opposite to the convex side of the ceramic plate 1a, a copper plate 1b is selectively disposed and fixed. A power element 3 is provided on the surface of a predetermined portion of the copper plate 1b with a high melting point solder 2 interposed therebetween.
Is fixed.

The electrodes are taken out from the upper surface of the power element 3 to the surface of the copper plate 1b by the bonding wires 4. Further, a terminal holder 6 with a built-in external electrode terminal is fixedly mounted on the copper plate 1b via the low melting point solder 5 to be erected.

The peripheral end of the ceramic plate 1a is mounted in a substrate mounting groove 8 provided in a lower part of a resin case (envelope) 7 made of a resin material.
Is pressed downward by a holding member 9 attached to the upper surface of the substrate mounting groove 8. Then, the substrate 1 and the resin case 7 are fixed by an adhesive 10.

Further, the space inside the resin case formed by the resin case 7 and the substrate 1 is filled with a silicone resin gel agent 11 as a lower layer filler and an epoxy resin casting agent 12 as an upper layer filler. Thus, the inside of the resin case 7 is sealed. The silicone resin gel agent 11 and the epoxy resin casting agent 12 are both curable resins.

A screw hole 13 for fixing an external radiator plate or the like is formed in an extension extending from the outer wall surface of the resin case 7 in a direction opposite to the substrate 1. Here, the external radiator plate is a radiator plate having a large heat capacity and externally attached to the module.

Next, each component of FIG. 1 will be described specifically. FIG. 2 is a cross-sectional view of the high thermal conductive substrate 1 of FIG.
a and a copper plate 1b selectively fixed to the surface thereof.

FIG. 3 is a perspective view showing the shape of the resin case 7 shown in FIG. 1. The resin case 7 has a rectangular box shape. The illustrated resin case 7 has a front side lid (a side lid in a board insertion direction) removed. It shows the state where it was turned on. As shown in FIG.
A substrate mounting groove 8 for inserting the substrate 1 along the side wall is provided at a lower portion on the inner side of the side wall, and a holding member 9 is attached along an upper surface of the substrate mounting groove 8. In addition, screw holes 13 for fixing the outer housing are formed in two externally extending portions of the left and right side walls of the resin case 7, respectively.

FIG. 4A shows a cross section taken along line XX ′ of FIG. 3 in a state where the substrate 1 is mounted on the resin case 7 in the direction of the arrow in FIG. FIG. 4B is an enlarged view of the portion A in FIG.

Here, the presser fitting 9 removes the backlash between the board 1 and the resin case 7 after being inserted and fixes the heat radiating surface 1c of the ceramic plate 1 to the external heat radiating plate with screws. It is necessary to contact the external heat sink with a certain pressure or more. Similarly, the thickness 7c of the lower end of the substrate mounting groove 8 in the resin case 7 is reduced with respect to the protruding surface 1d of the substrate 1 for such contact. The presser fitting 9 is attached to the resin case 7 by embedding it when the resin case 7 is molded.

FIGS. 5A and 5B show the resin case 7 of FIG.
3A is a diagram showing the shape of the front lateral lid 7a, FIG. 3A is a top view thereof, and FIG. 3B is a lateral view thereof. FIG.
As shown in FIG. 5A, cutouts 7b are formed at both ends of the front side lid 7a so that one end surfaces of the substrate mounting grooves 8 on the left and right side walls of the resin case 7 are engaged. As shown in the figure, a lower portion of the front side lid 7a is provided with a substrate mounting groove 8a in the same manner as the substrate mounting groove 8 of the resin case 7, and a holding metal 9a is similarly mounted along the upper surface thereof.

Next, a method of assembling a module using these components will be described. First, the power element 3 is placed on the pattern surface of the copper plate 1b on the
And fixed using ultrasonic bonding technology, etc.
The electrode is taken out from the upper surface of the power element 3 to the surface of the copper plate 1b by the bonding wire 4. The processing up to this point is the same as the conventional example using the DBC substrate except that the type of the substrate is different.

Thereafter, the substrate 1 on which the power element 3 is mounted
And the terminal holder 6 are fixed with a low melting point solder 5 using a positioning jig. Then, the structure in which the substrate 1 and the terminal holder 6 are integrated is inserted into the resin case 7 shown in FIG. 3 from the substrate mounting groove 8 and mounted (see FIG. 4A).

In the assembly after inserting the substrate 1 into the resin case 7 as described above, the resin case 7 is covered with the side cover 7a shown in FIG. At this time, the surfaces of the arrows in FIGS. 5A and 5B enter the inside of the resin case 7, and the substrate 1 is inserted into the substrate mounting groove 8 a of the lateral lid 7 a in the same manner as the substrate mounting groove 8 of the resin case 7. It will be.

Thereafter, the substrate 1 and the resin case 7 and the resin case 7 and the side lid 7a are bonded and fixed using an adhesive 10, respectively.

Thereafter, as in the conventional example, the silicone resin gel agent 11 is filled as the lower layer filler and the epoxy resin casting agent 12 is filled as the upper layer filler, and the inside of the resin case 7 is sealed.

FIG. 6 is a sectional view showing a main part of a high power semiconductor device according to a second embodiment of the present invention.

This embodiment is different from the first embodiment in that:
In order to increase the mechanical strength of the lower end of the substrate mounting groove 8 provided in the lower part of the resin case 7, a metal guide 21 made of steel or the like is embedded in this portion. The metal guide 21 is used for the resin case 7 in the same manner as the presser fitting 9.
Is embedded in the mold.

FIG. 7 is a sectional view showing a main part of a high power semiconductor device according to a third embodiment of the present invention.

This embodiment is different from the first embodiment in that
This is a point in which a holding bar 31 is provided to cross the inside of the resin case 7. The holding of the substrate 1 is performed not only around the inside of the resin case 7 but also by the holding bar 31. Thereby, the strength of the resin case 7 is improved.

FIG. 8 is a sectional view showing a main part of a high power semiconductor device according to a fourth embodiment of the present invention.

In this embodiment, the substrate 1 is made of the same DBC as the conventional one.
Instead of the substrate 41, it is possible to use a conventional substrate as described above.

FIG. 9 is a sectional view showing a configuration of a high power semiconductor device according to a fifth embodiment of the present invention.

In this embodiment, a ceramic material is used as a case material without using a resin. In this case, the substrate and the case are integrated by using the same material as the ceramic material of the substrate. The envelope 51 is manufactured. Thereby, the press fitting becomes unnecessary.

FIG. 10 is a sectional view showing a configuration of a high power semiconductor device according to a sixth embodiment of the present invention.

To attach the module to the external heat sink, it is necessary to fix it with screws.
In the fifth embodiment, all the fixing parts by the screws are on the resin case 7 side. In contrast to this, the present embodiment has a structure in which the ceramic of the substrate is fixed with screws. That is, the substrate 1A is made of ceramic larger than the resin case 7 with the resin case 7 mounted on the upper surface side thereof, and an external radiator plate is provided on an extension extending from the resin case 7 to the outside. A fixing screw hole 13A is formed.

Further, the thickness 61 of the substrate 1A immediately below the power element 3 is set to be thinner than a certain thickness because it becomes a resistance component against heat radiation. Further, the thickness of the portion (extended portion) 62 of the substrate 1A that is compressed by the screw is set to be thicker than that just below the power element 3 in order to enhance the mechanical strength.

In the first to sixth embodiments, the resin case 7 is provided as the envelope. However, the present invention is also applicable to a module in which the resin case 7 is omitted, for example. .

[0050]

As described in detail above, the first to fourth embodiments are described.
According to the invention of the present invention, the metal heat radiating plate conventionally used for fixing the substrate and the solder material for fixing the heat radiating plate to the substrate can be omitted, so that the life in the TFT test is greatly improved. It is possible to do. Further, since the durability is excellent, the reliability in practical use is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a high-power semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the high thermal conductive substrate 1 of FIG.

FIG. 3 is a perspective view showing a shape of a resin case 7 of FIG.

FIG. 4 is a view showing a state where the substrate 1 is mounted on a resin case 7;

FIG. 5 is a view showing a shape of a front side cover 7a of the resin case 7 of FIG.

FIG. 6 is a cross-sectional view showing a configuration of a main part of a high-power semiconductor device according to a second embodiment of the present invention.

FIG. 7 is a sectional view showing a configuration of a main part of a high-power semiconductor device according to a third embodiment of the present invention.

FIG. 8 is a sectional view showing a configuration of a main part of a high power semiconductor device according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing a configuration of a high power semiconductor device according to a fifth embodiment of the present invention.

FIG. 10 is a sectional view showing a configuration of a high-power semiconductor device according to a sixth embodiment of the present invention.

FIG. 11 is a sectional view showing a conventional module.

DESCRIPTION OF SYMBOLS 1a Ceramic plate 1b Copper plate 1, 1A board 3 Power element 6 Terminal holder 7 Resin case 8 Board mounting groove 9, 9a Holding metal 11 Silicon resin gel agent 12 Epoxy resin casting agent 13, 13A Screw hole 21 Metal Guide 31 Presser bar 41 DBC board 51 Envelope

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-142166 (JP, A) JP-A-2-110962 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 25/04

Claims (8)

(57) [Claims] 1. A substrate comprising a ceramic plate having an inverted convex cross section and a metal member formed on a main surface opposite to the convex side of the ceramic plate; and a power element mounted on a surface of the metal member of the substrate. A high-power semiconductor device comprising: 2. The package according to claim 1, further comprising a substrate on which the power element is mounted, a terminal holder electrically connected to the power element, and an envelope for casing the power element and the terminal holder. A high-power semiconductor device in which a resin is filled in a space formed inside the envelope formed by the substrate and the terminal holder so as to lead the terminal holder to the outside, wherein a substrate mounting groove is formed at a lower portion inside the side wall of the envelope. Wherein the substrate is mounted in the substrate mounting groove to serve as a bottom cover of the envelope. 3. The substrate according to claim 1, wherein a lower end of a peripheral end of the substrate is cut out to form an inverted convex cross section, and a peripheral end of the substrate is mounted in the substrate mounting groove. Item 3. A high-power semiconductor device according to item 2. 4. The high-power semiconductor device according to claim 2, wherein a holding member for pressing the substrate is provided on an upper surface of the substrate mounting groove. 5. The substrate comprises: a ceramic member having an inverted convex cross section; and a metal member formed on a main surface of the ceramic member opposite to the convex surface, wherein the power element is provided on a surface of the metal member. The high power semiconductor device according to claim 2, wherein the device is mounted. 6. The high-power semiconductor device according to claim 2, wherein a metal guide is buried in a side wall of the envelope so as to be located below the substrate mounting groove. 7. A screw hole for fixing an outer casing is formed in an outer extension of the envelope extending from an outer wall surface of the envelope in a direction opposite to the substrate. 2 to claim 6
The high-power semiconductor device according to claim 1. 8. A package comprising a substrate on which a power element is mounted, a terminal holder electrically connected to the power element, and an envelope casing the power element and the terminal holder. A high-power semiconductor device in which a resin is filled in a space formed inside the envelope formed by the substrate and the terminal holder so as to lead the terminal holder to the outside, wherein the substrate is a bottom portion of the envelope. A high-power semiconductor device formed integrally with the envelope.