JPH10214930A - Coaxial laminate cooling structure for flat semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact stacked structure of a flat semiconductor device and a liquid-cooling block with high utility. SOLUTION: A laminate of flat semiconductor device 1 is constituted by using liquid-cooling block fins for the element formed to open an inlet of an introducing tube 4 and a discharge port of a discharge tube 5 in the same rotating direction by providing a refrigerant passage in a liquid-cooling block 2 and disposing the tube 4 at a refrigerant introducing side and the tube 5 at the exhaust side at rotary symmetrical position, a cylindrical conductor 3 connected to one main electrode of the entire laminate is concentrically disposed at a central axis of the laminate, the conductor 3 is divided to the central axis symmetrically and connected. The conductor 3 is constituted by the structure divided at the central axis symmetry, the structure covered on a surface of the part except the connecting part of the conductor 3 with an insulator, and the conductor 3 is provided with through holes at positions corresponding to terminals of the device 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for a flat semiconductor device, and more particularly to a coaxial stacked cooling structure for a flat semiconductor device for reducing wiring inductance existing in a current path.

[0002]

2. Description of the Related Art In general, pressure contact and cooling of a flat semiconductor element for the purpose of multi-series connection for high voltage are performed by applying a press contact force to an entire laminate of a plurality of flat semiconductor elements and blocks alternately stacked. A method of cooling by heat radiation from a liquid-cooled block is adopted. In this case, the main electrodes of the entire stack of the flat semiconductor element group are located at both ends of the stack.

[0003] The electrical insulation of the stacked body of flat semiconductor element groups is performed by electrically insulating the semiconductor element groups and main electrodes, etc., which are integrally stacked, and a pressurizing mechanism for applying a predetermined pressing force to the semiconductor elements. In addition, an electrically insulating space for the refrigerant introduced into the block is required. Further, there are peripheral components that need to be arranged close to the semiconductor device, such as a driving circuit for the semiconductor device and a snubber circuit component for protection, around the semiconductor device. The insulation space increases.

Hereinafter, an example of the liquid cooling block according to the prior art will be described with reference to FIGS. 6 and 7. FIG. In the liquid cooling block 211 shown in FIG. 6, two heat transfer holes h are provided in a liquid cooling block made of copper, and a U-shaped heat transfer tube 171 formed of a copper tube is inserted into the heat transfer hole h. Further, the through hole a is an insertion hole for a pressure contact clamp when the plurality of liquid cooling blocks 211 and the flat semiconductor element are pressed against each other with a predetermined pressure.

When a flat semiconductor element is cooled by the liquid cooling block having the conventional structure, it is assembled and used, for example, as shown in FIG. That is, in FIG. 7, the three flat semiconductor elements 1 are sandwiched between four liquid cooling blocks 211 to form a single stacked body, and the entire stacked body is integrally pressed by the press-contact clamp 111. The method of cooling the integrally laminated flat semiconductor element 1 is as follows. A refrigerant is introduced from a refrigerant introduction device provided outside the figure by clamping a refrigerant transport pipe 121 with a clamp 141, and a liquid cooling block 211 at the uppermost part is cooled. Heat transfer tube 17
1 is introduced through the inlet 171a and discharged through the outlet 171b. A connecting pipe 131 made of an insulating material for guiding the refrigerant from the outlet 171b to the inlet 171a of the next liquid cooling block 211 provided at the lower portion is connected using a fastener 141. While securing electrical insulation that can withstand the voltage applied between the semiconductor elements 1,
This is achieved by forming a closed loop piping system that returns from the refrigerant discharge pipe 121 on the refrigerant discharge side to the refrigerant introduction device outside FIG. 7 through the discharge port 171b of the liquid cooling block 211 at the uppermost stage. If the refrigerant is inexpensive and safe, such as water,
The above-mentioned closed loop piping system may be opened to make the refrigerant disposable.

As is clear from the above mechanism, since the integrated liquid cooling block 211 constitutes a single piping system, the heat dissipation characteristics and the thermal resistance of the flat semiconductor element are set to be constant. , The mechanical characteristics of the refrigerant flow rate and pressure loss of each pipe serving as the refrigerant path, and the
The electrical characteristics applied in between are major factors that determine the size of the structure. On the other hand, if a flat semiconductor element and a liquid-cooled block that are integrally laminated are formed as a group of multi-series laminates to form a group of elements for a high-voltage circuit, the number of groups in a series is several times the withstand voltage of the flat semiconductor element. The device can be used with an increased withstand voltage of the entire device. Therefore, when FIG. 7 is used as a multi-series laminate of one flat semiconductor element, the liquid cooling blocks 211 made of copper at the uppermost and lowermost portions in FIG. 7 are used as two main electrodes of the entire switch. At this time, the connection for the circuit configuration of the application device from both main electrodes,
The space around the element such as the above-described press-contact mechanism, liquid cooling block, and each piping system is avoided, and a space for securing electrical insulation is required. In addition, although not particularly shown, generally, a gate circuit or a balancer resistor and a snubber circuit which are connected in parallel close to each flat semiconductor element are used, so that the wiring length is inevitably long and wide. Will be.

[0007]

Therefore, as described above, in the laminated structure according to the prior art, when the main electrodes at both ends are connected to an external circuit (including a gate circuit, a balancer resistor and a snubber circuit). In addition, it is necessary to secure the electrical insulation distance by avoiding the arrangement of the piping and peripheral parts forming the above-described press-contact mechanism and the refrigerant path, and to connect the laminate of the flat semiconductor elements to the external circuit. The connection loop with the circuit expands. As a result, the wiring route when the stacked body of the flat semiconductor element and the liquid cooling block is incorporated into the circuit of the application device becomes longer, and the wiring inductance increases. In particular, it is difficult to apply the present invention to applications in which the oscillation cycle of the resonance circuit with the capacitance included in the external circuit is extremely narrow and a current pulse having a large peak value needs to be generated, such as a pulse power supply application. Was. Therefore, in the conventional pulse power supply application, the purpose has been achieved by a technique of installing two to three auxiliary circuits called a magnetic compression circuit at the subsequent stage of a switching circuit using a semiconductor element to compress the pulse width narrowly.

[0008] The same applies to a general power conversion device and the like. A power conversion device is formed by using a plurality of stacked bodies formed of the above-described flat semiconductor element groups, and thus, a mounting space and high-voltage insulation are required. However, there has been a problem that the distance between the semiconductor devices has increased, the size of the device has been increased, and the withstand voltage of the semiconductor element has to be increased due to an unnecessary increase in wiring inductance.
An object of the present invention is to improve the disadvantages of the conventional structure and to provide a compact and highly practical stack structure of a flat semiconductor element and a liquid cooling block.

[0009]

Means for achieving the object of the present invention are as follows: (1) In the first aspect, a refrigerant passage is provided inside the liquid cooling block, and an inlet pipe and a discharge pipe are provided on the refrigerant introduction side. On the side, the discharge pipes are arranged so as to be rotated relative to each other, and a liquid cooling block in which the introduction port of the introduction pipe and the discharge port of the discharge pipe open in the same rotation direction is used. And a cylindrical conductor connected concentrically to the central axis of the laminate and connected to one main electrode of the laminate.

(2) In claim 2, the entire surface is covered with an insulator over the inner and outer peripheral portions of the cylindrical conductor, except for the connection portion between the flat semiconductor element and the liquid cooling block laminate and the other main electrode portion. I covered it.

(3) In the third aspect, the cylindrical conductor is divided into a plurality of conductor pieces symmetrical with respect to the central axis, and portions other than the connection portion are covered with an insulator, and a predetermined interval is provided between the respective conductor pieces. It has been provided.

(4) In claim 4, a through hole is provided in the cylindrical portion of the cylindrical conductor at a position facing the auxiliary electrode of the laminated flat semiconductor element, and the through hole is provided outside the coaxial laminated body of the flat semiconductor element. It has a through hole for connection with a peripheral circuit element of a semiconductor element.

Next, the operation will be described. The cooling pipe system of the flat semiconductor element and the liquid cooling block is rotationally symmetric, using a liquid cooling block in which the refrigerant inlet pipe and the discharge pipe are at the positions to be rotated with each other and does not cause interference in connection with the communication pipe. , So that it is arranged concentrically with the central axis of the laminate of the flat semiconductor element and the liquid cooling block, and a cylindrical conductor connected to one main electrode of the laminate can be easily installed, and the wiring path Can be made a reciprocating conductor. That is, the direction of the main current in the conduction path formed by the stacked body of the flat semiconductor element and the liquid-cooled block and the direction of the main current flowing in the cylindrical conductor have a relationship opposite to each other. Therefore, the wiring inductance caused by the reciprocating wiring configuration between the entire stack and the tubular conductor formed by the flat semiconductor element and the liquid cooling block can be reduced.

Except for the connection between the flat semiconductor element and the liquid-cooled block laminate and the other main electrode, the entire surface is covered with an insulator over the inner and outer peripheral parts of the cylindrical conductor, so that the flat semiconductor element and Electrical insulation between each part of the liquid cooling block and each conductive part such as a piping system becomes easy, the insulation distance can be minimized, and a compact device can be obtained. The cylindrical conductor is divided into a plurality of conductor pieces symmetrically with respect to the central axis, and the portions other than the connection portions are covered with an insulator, and the conductor pieces are individually insulated by providing predetermined intervals between the conductor pieces. The gate circuit, balancer resistor and snubber circuit of a flat semiconductor element can be connected using the gap between the pieces, and it can be easily placed close to the outside without increasing the electrical insulation distance and without increasing the wiring inductance. Can be connected to a circuit. By dividing the cylindrical conductor into a plurality of conductor pieces symmetrically with respect to the central axis, it is possible to mount the plurality of conductor pieces after laminating the flat semiconductor element and the liquid cooling block fins and assembling the pressure welding. Is easy. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially sectional side view illustrating a coaxial laminated cooling structure of a flat semiconductor device according to one embodiment of the present invention, and FIG. 2 is a side view of FIG. 3 is a cross-sectional view of a cylindrical conductor, FIG. 4 is a perspective view of a divided cylindrical conductor, and FIG. 5 is a cross-sectional view for assembling the cylindrical conductor of FIG. 1 and 2, a flat semiconductor device 1 and a liquid cooling block 2 are provided at the center of the drawing.
In addition, an inlet pipe 4 for introducing refrigerant into the liquid cooling block and a discharge pipe 5 for discharging refrigerant, a pressure contact clamp 11 for integrally pressing the flat semiconductor element 1 and the liquid cooling block 2 and the like, and a cylindrical tube of the present invention. A conductor 3 is provided. Here, 6 is an insulating seat, 7
Is an insulating plate, 8 is an insulating portion of one main electrode, 9 is a conductor portion of one main electrode, 10 is a conductor portion of the other main electrode, 13 is a communication tube, 14 is a fastening tool, and 15 is another main electrode. It is an insulating part.

That is, a laminated body of a plurality of flat semiconductor elements 1 and a plurality of liquid cooling blocks 2 is formed, and the cooling of each liquid cooling block 2 is performed in a cascade by introducing a cooling medium. In structure, liquid cooling block 2
The liquid cooling block 2 has an inlet pipe 4 on the refrigerant inlet side and an outlet pipe 5 on the outlet side so as to be substantially rotatable relative to each other. A liquid cooling block 2 in which the opening and the discharge port of the discharge pipe 5 are opened in the same rotation direction, and the flat semiconductor element 1 and the liquid cooling block 2 are formed.
Are formed in a plurality of sets, and the outer periphery of the stacked body is covered with a tubular conductor 3 and the conductor 3
And the other main electrode (insulating part 15, conductor part 10) of the laminate.

As shown in FIG. 3, the cylindrical conductor 3 includes an insulating portion 3A of a cylindrical conductor whose surface is insulated and coated, and a cylindrical conductor portion 3A.
B, upper cylindrical conductor 3C, through-hole H of the cylindrical conductor, and conductor part 10 of the other main electrode brazed to cylindrical conductor 3. In addition, the through hole H of the cylindrical conductor is provided at a position corresponding to the auxiliary electrode and the like of the flat semiconductor element 1 and serves as an outlet for connecting a gate circuit, a snubber circuit, and the like and for taking out the refrigerant transport pipe 12. Further, the conductor section 9 of one main electrode whose surface is covered with the insulating section 8 of one main electrode is brazed to the uppermost liquid cooling block 2 shown in FIG.

In the apparatus constructed as described above, a multi-series body is formed in which the upper part of the flat semiconductor element 1 arranged at the center is the anode and the lower part is the cathode, and the bottom of the lowermost liquid cooling block 2 is formed. And the bottom cylindrical conductor 3D are brought into pressure contact with each other on the upper surface of the flat semiconductor element 1
The current flowing through the cylindrical conductor 3 is in a direction opposite to the current direction of the flat semiconductor element 1 with respect to the current flowing from the flat semiconductor element 1 to the bottom. Therefore, the current flowing through the flat semiconductor element 1 and the current flowing through the cylindrical conductor 3 cancel each other's magnetic flux, thereby minimizing the inductance of the entire device.

Next, another embodiment of the cylindrical conductor of the present invention will be described with reference to FIGS. FIG. 4 is a perspective view showing a conductor 31 having a structure formed by dividing the cylindrical conductor 3 shown in FIG.
1B and an insulating portion 31D of a plurality of divided tubular conductors 31C. The insulating portion 31D of each of the divided tubular conductors 31C is assembled to the bottom tubular conductor 31A and the upper tubular conductor 31B by screwing, respectively, but can be similarly configured by means such as brazing. If the tubular conductor 31 obtained in this way is replaced with the tubular conductor 3 of FIG. 1, a slight leakage of magnetic flux will occur, but it acts exactly as in FIG. The gap can be used as a connection of an auxiliary circuit such as a gate circuit and a snubber circuit to the flat semiconductor element 1 and as an outlet of the refrigerant transport pipe 12.

FIG. 5 is a cross-sectional view in which an insulating cap 16 for insulating the conductor portion 10 of the other main electrode and the conductor portion 9 of one main electrode shown in FIG. 2 is provided.
FIG. 3 is a cross-sectional view which also serves as a conductor 31 of the first embodiment, and performs insulation protection against high voltage. In addition, the lower divided tubular conductor 3E can also perform insulation protection in the same manner as the insulation cap 16, but FIG. As explained above,
The present invention provides a coaxial laminated cooling structure of a flat semiconductor element having a low inductance, which is obtained by skillfully combining the laminated structure of the flat semiconductor element 1 and the liquid cooling block 2 with the cylindrical conductors 3 and 31. .

[0021]

As described above, according to the present invention, the wiring structure is extremely small for a high voltage circuit by skillfully combining the laminated structure of the flat semiconductor element and the liquid cooling block and the cylindrical conductor. In addition, the heat dissipation efficiency and the mounting density are high, and a compact cooling structure of a flat semiconductor element as a whole can be obtained. In addition, the cylindrical conductor can be mounted and assembled after lamination pressure welding of flat semiconductor elements and liquid cooling blocks,
From this structure, it is possible to obtain a laminated cooling structure of a flat semiconductor element which can be easily connected to gate circuits and snubber circuit components installed around the flat semiconductor element, and is extremely useful in practical use.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view showing one embodiment of the present invention.

FIG. 2 is a side view of the embodiment of FIG. 1 of the present invention rotated 90 degrees.

FIG. 3 is a sectional view showing a cylindrical conductor of the present invention.

FIG. 4 is a perspective view showing another embodiment of the present invention.

FIG. 5 is a perspective view of the assembled cylindrical conductor of the present invention.

FIG. 6 is a perspective view of a conventional liquid cooling block fin.

FIG. 7 is an explanatory diagram showing one example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flat semiconductor element 2,211 Liquid cooling block 3,31 Conductor 4 Inlet pipe 5 Discharge pipe 6 Insulation seat 7 Insulating plate 8,15 Main electrode insulating part 9,10 Main electrode conductor part 11,111 Pressure contact clamp 12 Refrigerant transportation Pipes 13,131 Connecting pipes 14,141 Clamping tool 16 Insulating cap 171 Heat transfer pipe

Claims (4)

[Claims] An indirect cooling structure of a flat semiconductor element, comprising a stacked body of a plurality of flat semiconductor elements and a plurality of liquid cooling blocks, wherein the cooling of each liquid cooling block is performed in a cascade by introducing a refrigerant. A coolant passage is provided inside the cold block, and the liquid cooling block has an inlet pipe on the coolant inlet side,
On the discharge side, the discharge pipes are arranged so as to be substantially rotatable with each other, and a liquid cooling block in which the inlet of the inlet pipe and the outlet of the discharge pipe open in the same rotation direction with each other is formed. A laminated body is formed by laminating a plurality of pairs of liquid-cooling blocks in pairs, and the outer periphery of the laminated body is covered with a cylindrical conductor, and the conductor is connected to one main electrode of the laminated body. Coaxial laminated structure of a flat semiconductor element. 2. A structure in which the entire surface is covered with an insulator over the inner and outer peripheral portions of a cylindrical conductor, except for a connection portion between the flat semiconductor element and the liquid cooling block laminate and the other main electrode portion. 2. A coaxial laminated cooling structure for a flat semiconductor device according to claim 1, wherein: 3. The method according to claim 1, wherein the cylindrical conductor is divided into a plurality of conductor pieces symmetrically with respect to the central axis, a portion excluding a connection portion is covered with an insulator, and a predetermined interval is provided between the conductor pieces. 2. The coaxial laminated cooling structure for a flat semiconductor device according to claim 1. 4. A through hole is provided in the cylindrical portion of the cylindrical conductor at a position facing the auxiliary electrode of the stacked flat semiconductor element,
4. The cooling structure according to claim 1, further comprising a through hole for connection to a peripheral circuit element of the semiconductor element provided outside the coaxial stacked body of the flat semiconductor element. .