JPH06196625A - Power module - Google Patents

Abstract

PURPOSE:To enlarge the contact area between a substrate and a heat radiating body and to improve the heat dissipating efficiency of a power chip, which is attached to the substrate. CONSTITUTION:In a power module 29, a power chip 19 is mounted, and the power chip 19 can be connected to a heat radiating body 25 thermally and mechanically. In this power module, a substrate 11, which is formed of a heat conducting member in the approximately cylindrical shape, and the power chip 19, which is attached to the edge of the substrate 11, are provided. A male screw part 24 of the substrate is screwed into a female screw part 27 formed in the heat dissipating body 25. Thus the heat dissipation of the power chip 19 is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power module, and more particularly to a power IC, a power transistor or the like (hereinafter referred to as a power chip) mounted thereon, which can be easily mounted on a housing or a radiator while maintaining high heat radiation efficiency. Regarding possible power modules.

[0002]

2. Description of the Related Art A power chip used for electric power is generally attached to a radiator (heat sink), a base having a large heat capacity, a casing or the like in order to prevent a temperature rise. FIG. 3 is a perspective view showing a conventional power module. The power module shown in FIG. 3 has a pedestal portion 1 having a rectangular shape on which an unillustrated power chip is mounted on its upper surface, and a male screw portion 3 formed on the lower surface of the pedestal portion 1. The male screw part 3 is adapted to be screwed into a female screw part 7 formed on the radiator 5. Therefore, when the male screw portion 3 is screwed into the female screw portion 7 of the heat radiator 5, the pedestal portion 1 is fixed while being placed on the heat radiator 5. In the power module thus configured, when the power chip generates heat, the heat is conducted to the pedestal 1, and the heat conducted to the pedestal 1 is conducted to the radiator 5 via the male screw portion 3 and the female screw portion 7. Radiating body 5
The heat is radiated from the device and the temperature rise of the power chip is prevented.

[0003]

However, in such a conventional power module, the pedestal portion 1 is
Since it was fixed to the radiator 5 via the male screw portion 3 protruding from a part of the lower surface, it was not possible to secure a sufficient contact area with the radiator 5. Therefore, the power chip can transfer the heat to the radiator 5 only with a small contact area only from the male screw part 3, and the heat stays in the pedestal part 1, so that the heat dissipation efficiency can be sufficiently enhanced. There was a problem of not having. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power module capable of increasing a contact area between a pedestal portion and a heat radiator, thereby improving heat radiation efficiency of a power chip. .

[0004]

In order to achieve the above object, according to the present invention, there is provided a power module having a power chip mounted thereon and capable of thermally and mechanically coupling the power chip to a radiator. In the power module,
A base formed of a substantially columnar heat conductive member and having a male screw portion on the outer peripheral surface thereof and a power chip attached to an end face of the base body are provided, and the male screw portion of the base body is formed on a radiator. The power chip is radiated by being screwed into the female screw portion.

[0005]

In the power module having the above structure,
Most or all of the outer surface of the base body excluding both end surfaces can be male screw parts, and the entire male screw parts are screwed into the female screw parts of the radiator. Therefore, the contact area between the base on which the power chip is mounted and the radiator is large, the heat conduction path of the power chip is sufficiently secured, and heat is efficiently radiated.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the power module according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view of a power module according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view of the power module. Cylindrical base 1
A recess 13 is formed on the end face of the recess 1.
a is a flat surface. An insulating film (such as aluminum nitride AN) 15 (see FIG. 2) is formed on the bottom surface 13a, and a circuit (circuit pattern) 17 is formed on the insulating film 15. That is, the bottom surface 13a is itself a circuit board. A power chip 19 is mounted on the circuit pattern 17, and the power chip 19 has a flat bottom surface for conducting heat to the bottom surface 13a.
Each electrode on the power chip 19 on the circuit pattern 17 is
Wire bonding is performed on a predetermined electrode pad of the circuit pattern 17. The circuit pattern 17 may be directly formed on the bottom surface 13a as described above, or may be a circuit board that is a separate body attached to the bottom surface 13a.

A male screw portion 21 is formed on the outer periphery of the base 11 in the direction of the central axis of the base 11, and the outer peripheral surface of the base 11 is mostly or entirely a screw surface. Also, the base 1
A concave groove 23 (see FIG. 2) is formed on the lower surface of 1 and the concave groove 23 is adapted to be fitted with a driver, a jig, or the like. On the other hand, the radiator 25 is formed with a female screw portion 27 with which the male screw portion 21 is screwed, and the female screw portion 27 has a depth for accommodating at least most of the base 11. That is, by screwing the male screw portion 21 into the female screw portion 27, the base 11
Is inserted into the female screw 27. Then, the base body 11 is inserted into the radiator 25 and then wire-bonded to an external circuit. As described above, the base 1
The power module 29 is configured with the power chip 19, the power chip 19, and the male screw portion 21 as main members.

[0008] The power module 2 configured in this way
In No. 9, when the base 11 is screwed into the female screw portion 27, the entire outer peripheral surface of the base 11 contacts the inner peripheral surface of the radiator 25, and the base 11 contacts the radiator 25 in a large area. Therefore, the heat conduction path is sufficiently secured. Therefore, the heat from the power chip 19 is quickly conducted to the radiator 25, and the heat is not accumulated in the base 11. If a step portion or the like is formed at a predetermined depth of the female screw 27, when the base 11 is screwed into the female screw 27, the base 11 can be positioned at a predetermined position.

[0009]

As described above in detail, in the power module according to the present invention, the power chip is provided on the end face of the base body, and the male screw portion to be screwed into the female screw portion of the radiator is formed on the outer peripheral surface of the base body. Therefore, the contact area between the base and the radiator becomes large, and the heat conduction path of the power chip can be sufficiently secured. As a result, it becomes possible to significantly improve the heat dissipation efficiency of the power chip.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a power module according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a detailed configuration of the power module in FIG.

FIG. 3 is a perspective view showing an external structure of a conventional power module.

[Explanation of symbols]

 11 Base 13 Recess 13a Bottom 15 Insulating Film 17 Circuit Pattern 19 Power Chip 21 Male Screw Part 23 Recessed Groove 25 Heat Dissipator 27 Female Screw Part 29 Power Module

Claims (1)

[Claims] 1. A power module having a power chip mounted thereon, the power chip being capable of being thermally and mechanically coupled to a heat radiator, the power module being composed of a substantially columnar heat conductive member and having a male screw portion on an outer peripheral surface thereof. And a power chip attached to an end surface of the base, and the male chip portion of the base is screwed into a female screw portion formed on the radiator to radiate heat from the power chip. A power module characterized in that.