JP3004548B2 - Semiconductor stack - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor stack in which a flat semiconductor element and a heat sink are laminated and an insulating band is used to apply elastic pressing force.

[0002]

2. Description of the Related Art In general, a semiconductor converter has a plurality of semiconductor elements and heat sinks for cooling the elements alternately stacked, and a holding plate, stud, and the like for holding an elastic pressing force (pressing force). A plurality of units called modules, each containing a semiconductor stack (hereinafter simply referred to as a stack) made of springs or the like, are mounted.

FIG. 7 shows a circuit in a typical module. The module 1 includes a plurality of semiconductor elements 3 (six in the figure) and ancillary circuits such as an anode reactor 6, a voltage dividing resistor 4A, a snubber resistor 4B, and a snubber capacitor 5. , The portion indicated by the broken line is the stack 2.

FIG. 8A is a front view showing a conventional stack 2, and FIG. 8B is a side view of the stack 2. As shown in FIG. 8, an insulating flat plate 11 made of a glass cloth laminated material or the like is fixed to the holding plate 10 with bolts 19 to form a frame for stacking. The holding plates 10 at both ends constitute the element 3 and the heat sink. 7, a through hole 17 of one of the holding plates is provided with a freely movable pressure rod 15, a thread is formed on the pressure rod 15, and a lock nut 18 is attached. A disc spring rod 16 which is freely movable and has a disc spring 12 is provided in a through hole 17 of the other holding plate. In addition, the through hole 17 of the holding plate 10 and the pressure rod 1
5. The laminated body of the element 3, the heat sink 7, and the like, and the disc spring rod 16 are arranged so as to coincide with the pressing axis. Pressing during stacking is performed by attaching a pressing unit 22 (not shown) to the holding plate 10 by an appropriate method.

The holding plate 10 is electrically at the potentials A and K in FIG. 7 and is insulated from the stage 8 by an insulator 21. Further, since the insulating plate 11 itself is an insulator, it is insulated from each of the holding plates 10.

[0006]

In recent years, as the capacity of a thyristor element has been increased, the diameter of the element has increased, and the pressure contact force of the element has increased. This is to reduce the contact thermal resistance and the electrical resistance at the flat semiconductor element post surface, and the magnitude of the pressure contact force is proportional to the contact area.

FIG. 9A is a view for explaining the breakage of the insulating flat plate 11, and FIG. 9B is a partial sectional view for explaining the force acting on the mounting portion between the insulating flat plate 11 and the holding plate 10. When the element 3 is pressurized and maintained by the above-described method, a shear force due to the element pressure contact force acts on the fitting portion between the holding plate 10 and the fixing bolt 19 as shown in FIG. 9B. Further, as shown in FIG. 9A, a shear force as shown in FIG. In particular, when a shearing force exceeding the designed value acts on the mounting hole for the fixing bolt 19 on the insulating flat plate 11, the break occurs at "X" or "Y" in FIG. 9A. Even if the insulating plate 11 is optimally designed, its breaking load Fa is at most a value given by the following equation.

[0008]

## EQU1 ## Fa = .sigma.a.times. (W-2d) .times.t (1) .sigma.a: Tensile breaking stress of insulating plate w: Width of insulating plate d: Diameter of fixing hole of insulating plate t: Plate of insulating plate Thickness Actually, stress concentration occurs in the fixing holes formed in the insulating plate 11, so that the breaking load Fa is less than the value obtained by the equation (1).

In order to design a stack corresponding to an increase in the capacity of the element, it is necessary to design a stack that sufficiently withstands the pressing force of the element. As a matter of course, in order to increase the breaking load of the equation (1), the thickness t and the width w of the insulating plate must be increased. However, if the diameter of the fixing bolt 19 is not large, the bolt is broken by the applied load, so that the insulating plate 11 becomes larger. In addition, the holding plate 10 is also fitted with the thick fixing bolt 19, so that the holding plate 10 becomes large in size, which is a factor contradictory to the demand for compactness and light weight.

It is an object of the present invention to provide a semiconductor stack using an insulating band which overcomes the above-mentioned problems, is simple, lightweight and easy to press-connect, and can maintain a press-contact force for a long period of time.

[0011]

In order to achieve the above object, the invention according to claim 1 provides a laminate in which a plurality of flat semiconductor elements and heat sinks are alternately laminated, and one of the laminates. A pressing-side pressing block provided at one end, a disc spring-side pressing block provided at the other end, and a pressure rod mounted on the pressing-side pressing block and having a threaded process capable of freely moving in the stacking direction. A lock nut attached to the pressure rod, a disc spring rod attached to the disc spring-side holding block, movable in the stacking direction, and fitted with a disc spring, the stacked body and the press-side presser. The insulating band is made of a glass fiber reinforced plastic insulating material surrounding the block and the disc spring side holding block, and the radius of the curved portion of the insulating band is between 2 and 12 times the thickness of the curved portion. It is obtained by and sets to one.

According to a second aspect of the present invention, a protrusion is provided at an edge of the insulating band, and the sectional shape is a U-shape or H-shaped.
Or a L-shape, wherein the projecting portion is provided with a hole or a groove for mounting a component.

Further, the invention according to claim 3 is characterized in that the insulating band is provided with an insulating member for mounting components. Further, the invention according to claim 4 is characterized in that a plurality of the insulating bands are laminated and bonded.

[0014]

According to the first aspect of the present invention, the tensile strength of the insulating band is based on the fact that the tensile strength is changed by the ratio of the radius of the curved portion of the insulating band to the thickness of the insulating band. If the ratio is between 2 and 12, an optimal semiconductor stack can be provided.

According to the second aspect of the present invention, in addition to the effects of the first aspect, the insulating band is used as a component mounting member by utilizing a hole or a groove provided in a protruding portion of the insulating band. It can also be used.

Further, according to the third aspect of the present invention, in addition to the effects of the first aspect, the insulating band can be used as a component mounting member without providing a protruding portion on the insulating band.

Further, according to the invention described in claim 4,
When the thickness of the insulating band is reduced, the ratio of the thickness to the radius of the curved portion becomes large and the strength becomes high even if the radius of the curved portion is small. Since the insulating bands thus formed are laminated, an insulating band having extremely high strength is obtained.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an insulation band according to the present invention. FIG. 1 in which the same parts as in FIG. 8 are assigned the same reference numerals is a configuration diagram showing one embodiment of the semiconductor stack according to the first aspect of the present invention.
(B) is a side view.

The stack 2 has a plurality of elements 3 (six in the figure) and heat sinks 7 alternately stacked, and a conductor 14 serving as an electric circuit connection terminal is disposed at both ends thereof, and a holding seat 13 is disposed outside the conductor 14. And a pressure rod 1 made of a U-shaped block provided at one end of the laminate and screwed to the center of the opening side so as to be movable in the laminating direction.
5 and a lock nut 1 screwed onto the pressure rod 15
And a U-shaped block provided at the other end of the laminated body, which is screwed to the center of the opening side movably in the laminating direction, and on which a disk spring 12 is mounted. A holding block provided with a spring rod 16 and an insulating band 2 made of, for example, glass fiber reinforced plastic insulation, surrounding the laminate and the pair of holding blocks.
3

In order to maintain an elastic pressing force on the semiconductor stack configured as described above, a predetermined pressing force F is applied by a press (not shown) as shown in FIG. 1B. Thereafter, the pressure rod 15 is lowered until it comes into contact with the presser seat 13, and is raised until the lock nut 18 comes into contact with the opening surface of the U-shaped block. In this state, no tensile force is applied to the insulating band 23, but when the press (not shown) is removed, the tensile force F is applied to the race track-shaped insulating band 23 as a reaction force of the pressing force. That is, the insulation band 2 has a structure in which the pressure contact force is confined inside the insulation band 23.
3, a tensile force as a reaction force of the pressing force is applied.

In the semiconductor stack configured as described above, as a result of an experiment, it was found that a breakdown due to a tensile force occurred near the boundary between the curved portion of the insulating band 23 and the direct portion.
Further, the ratio between the radius r of the curved portion of the insulating band 23 shown in FIG. 1 and the thickness t, and the tensile strength at break (MPa) “megapascal”
It has been clarified that the relationship shown in FIG.

As is clear from this characteristic, if the plate thickness is fixed, the tensile strength at break varies with the radius r of the curved portion of the insulating band 23. If the radius is twice as large as the plate thickness t, the insulating band 23 becomes insulated. Has a value S1 which is about half of the tensile strength of the base material. If the radius is 12 times the thickness t of the insulating band 23, the tensile strength of the insulating band becomes almost the same value S2 as the tensile strength of the base material.

Therefore, an optimum semiconductor stack can be provided from the radius r of the curved portion of the insulating band 23 which depends on the capacitance of the semiconductor stack, the pressure contact of the semiconductor element, and the like.

FIG. 3 is a perspective view of an insulating band according to another embodiment of the present invention. This embodiment shows that, when the capacity of the semiconductor stack is further increased, the insulating band 23 can be dealt with by providing four curved portions having a radius r. Also in this case, the relationship between the ratio of the radius r of the curved portion of the insulating band 23 to the plate thickness t and the tensile breaking strength (MPa) “megapascal” shows the characteristics shown in FIG.

FIG. 4 is a perspective view of an insulating band according to an embodiment of the present invention. This embodiment is shown in FIG.
As shown in the figure, a projecting portion is provided at a side end portion of the insulating band 23, the cross-sectional shape is U-shaped, and a hole 24 or a groove 25 for attaching a component is provided at the projecting portion. It is designed to attach various parts.

The protruding portion may be formed of the same material as the insulating band 23, or may be formed by any method such as casting a resin containing no glass fiber with a mold. Further, the cross-sectional shape may be a shape such as an H shape or an L shape. Also, the cross-sectional shape of the insulating band 23 is U-shaped (groove-shaped) or H-shaped.
By adopting the shape and the L shape, bending and deformation at the time of manufacturing can be prevented in addition to improvement in strength.

FIG. 5 is a perspective view of an insulating band according to an embodiment of the present invention. In this embodiment, wiring and piping components are mounted by attaching or fitting an insulating member 26 for mounting components to the insulating band 23. The stack can be fixed by attaching an insulating support member 27 for fixing the stack itself and supporting the insulating band 23.

FIG. 6 is a perspective view of an insulating band according to an embodiment of the present invention. Figure 6 shows the insulation band 2
3, an insulating band 23a of a thin plate having a curved portion with a radius r is manufactured, and an insulating band 23b having a larger radius of a curved portion than the insulating band 23a and an insulating band 2
3b, the insulating band 23c having a larger radius of one round curve portion is coated with the same resin as the FRP beforehand and inserted, so that the minute gaps between the large and small insulating bands are filled with the same resin as the FRP and bonded. I do. The same effect can be obtained by performing this operation in a resin tank. Alternatively, the same effect can be obtained even when the layers are laminated without bonding.

When thin insulating bands are laminated to form an insulating band, the tensile strength becomes the sum of the tensile strength of each of the laminated insulating bands, and a high-strength insulating band can be produced. Further, since the plate thickness is small, the radius of the curved portion can be reduced, so that an insulating band having a shape close to a square can be formed. Alternatively, even if the innermost insulating band breaks, the progress of the break can be stopped at the next insulating band.

[0030]

As described above, according to the first aspect of the present invention, the radius r of the curved portion of the insulating band 23, which depends on the capacitance of the semiconductor stack, and the pressing force of the semiconductor element are taken into consideration. Thus, a semiconductor stack having an optimal shape can be provided.

Further, in the inventions according to the second and third aspects, in addition to the effects of the first aspect, the insulating band can be used as a member for mounting components. Furthermore,
According to the invention as set forth in claim 4, by forming the insulating bands by laminating the insulating bands of the thin plates, the tensile strength becomes the sum of the tensile strength of each of the laminated insulating bands, thereby providing a high-strength insulating band. can do.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a semiconductor stack showing one embodiment of the invention described in claim 1, wherein (a) is a front view and (b) is a side view.

FIG. 2 is a diagram showing a relationship between a radius of a curved portion and a thickness of the semiconductor band on a tensile breaking strength of an insulating band of a semiconductor stack.

FIG. 3 is a perspective view showing another embodiment of the insulating band according to the present invention.

FIG. 4 is a perspective view of the insulating band according to the second embodiment;

FIG. 5 is a perspective view of the insulating band according to the third embodiment;

FIG. 6 is a perspective view of the insulating band according to the invention of claim 4;

FIG. 7 is a circuit diagram of a module unit constituting the conversion device.

8A and 8B are configuration diagrams of a conventional semiconductor stack, in which FIG. 8A is a front view and FIG. 8B is a side view.

9A and 9B are diagrams for explaining the shearing force applied to the insulating plate and the holding plate of the conventional semiconductor stack, wherein FIG. 9A is a diagram of the shearing force applied to the insulating plate, and FIG. Diagram of the applied shear force.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Thyristor module 2 ... Semiconductor stack 3 ... Semiconductor element 4A ... Divider resistance 4B ... Snubber resistor 5 ... Snubber capacitor 6 ... Anode reactor 7 ... Heat sink 8 ... Stage 10 ... Holding plate 11 ... Insulating flat plate 12 ... Belleville spring 13 ... Holder 14 ... Conductor 15 ... Pressing rod 16 ... Belleville spring rod 17 ... Through hole 18 ... Lock nut 19 ... Bolt 20 ... Mounting bracket 21 ... Insulator 22 ... Pressing unit 23 ... insulation band 24 ... hole 25 ... groove 26 ... insulation member 27 ... insulation support member

Claims (4)

(57) [Claims] 1. A laminated body in which a plurality of flat semiconductor elements and heat sinks are alternately laminated, a pressing-side pressing block provided at one end of the laminated body, and a disc spring side provided at the other end. A presser block, a pressurized rod attached to the presser-side presser block, and having a threaded process capable of freely moving in the stacking direction, a lock nut mounted on the presser rod, and a disc spring-side presser block. A conical spring rod which is mounted and can be freely moved in the laminating direction and on which a conical spring is mounted, and an insulating band made of a glass fiber reinforced plastic insulating material surrounding the laminate, the pressing side holding block and the conical spring side pressing block. And the radius of the curved portion of the insulating band is set to twice to 12 times the thickness of the curved portion.
A semiconductor stack characterized by being set at any one of the times. 2. A laminated body in which a plurality of flat semiconductor elements and heat sinks are alternately laminated, a pressing-side pressing block provided at one end of the laminated body, and a disc spring side provided at the other end. A presser block, a pressurized rod attached to the presser-side presser block, and having a threaded process capable of freely moving in the stacking direction, a lock nut mounted on the presser rod, and a disc spring-side presser block. A conical spring rod which is mounted and can be freely moved in the laminating direction and on which a conical spring is mounted, and an insulating band made of a glass fiber reinforced plastic insulating material surrounding the laminate, the pressing side holding block and the conical spring side pressing block. And the radius of the curved portion of the insulating band is set to twice to 12 times the thickness of the curved portion.
A semiconductor stack characterized by being provided with four or less protruding portions at an edge portion thereof and provided with holes or grooves for mounting components on the protruding portions. 3. A stacked body in which a plurality of flat semiconductor elements and heat sinks are alternately stacked, a pressing-side pressing block provided at one end of the stacked body, and a disc spring side provided at the other end. A presser block, a pressurized rod attached to the presser-side presser block, and having a threaded process capable of freely moving in the stacking direction, a lock nut mounted on the presser rod, and a disc spring-side presser block. A conical spring rod which is mounted and can be freely moved in the laminating direction and on which a conical spring is mounted, and an insulating band made of a glass fiber reinforced plastic insulating material surrounding the laminate, the pressing side holding block and the conical spring side pressing block. And the radius of the curved portion of the insulating band is set to twice to 12 times the thickness of the curved portion.
A semiconductor stack, wherein the insulating band is set to any one of two times and an insulating member for mounting components is provided on the insulating band. 4. A stacked body in which a plurality of flat semiconductor elements and heat sinks are alternately stacked, a pressing-side pressing block provided at one end of the stacked body, and a disc spring side provided at the other end. A presser block, a pressurized rod attached to the presser-side presser block, and having a threaded process capable of freely moving in the stacking direction, a lock nut mounted on the presser rod, and a disc spring-side presser block. A conical spring rod which is mounted and can be freely moved in the laminating direction and on which a conical spring is mounted, and an insulating band made of a glass fiber reinforced plastic insulating material surrounding the laminate, the pressing side holding block and the conical spring side pressing block. And the radius of the curved portion of the insulating band is set to twice to 12 times the thickness of the curved portion.
A semiconductor stack, wherein a plurality of insulating bands set at any one of two times are laminated and bonded.