JP2002314014A - Fixing structure for radiator in semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing structure by which a trouble such as chip cracking can be prevented by making a plate spring press the center of the resin case of a semiconductor device to prevent the concentration of mechanical stress on one side of the semiconductor device, and by which the semiconductor device can be mounted only by simple work such as pushing a bar-like mounting member into an insertion hole at mounting. SOLUTION: When the semiconductor device is mounted on an external radiator, the plate spring, the semiconductor device and the external radiator are arranged at prescribed positions, and the bar-like mounting member, for example, having a expandable/shrinkable tip is inserted into holes of the plate spring, the semiconductor device and the external radiator, and the member is pressed so as to prevent coming-off of the tip to be engaged with the insertion hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiator fixing structure for mounting a power semiconductor device to an external radiator.

[0002]

2. Description of the Related Art Conventionally, power transistors and power M
Generally, in a power semiconductor device such as an OSFET, the semiconductor device itself has a structure in which a heat sink (radiator plate) is integrated. There are quite a few cases where it is attached to a radiator and used.

In order to attach a semiconductor device to an external radiator in this way, as shown in FIG. 4, a screw 4 is passed through a screw through hole 3 provided in a heat sink of the semiconductor device 1 and an external radiator 5 is attached. Is configured to be fastened.

When a semiconductor device is screwed to an external radiator, if a tightening torque is too strong, a resin case (generally referred to as a semiconductor chip) accommodating the semiconductor device is cracked by mechanical stress, or conversely, If it is too weak, the adhesiveness between the semiconductor chip and the external radiator deteriorates, and the problem that the designed heat radiation effect cannot be obtained occurs. Therefore, in order to avoid these, a recommended value of the tightening torque is presented by the manufacturer, and the screw is basically tightened in the board mounting process in accordance with the recommended value.

[0005]

However, in reality, troubles such as chip cracks and insufficient heat radiation effects due to improper tightening torque are unavoidable. Also,
As another problem, there is a current situation that it is difficult to automate the screw tightening work, and the trouble has hindered the efficiency of the board mounting.

The present invention has been made based on the above circumstances, and aims at avoiding chip cracks and improving the heat radiation effect, and furthermore, it is possible to automate the mounting of chips to a radiator. An object of the present invention is to provide a radiator fixing structure for a semiconductor device, which can enhance the efficiency of mounting a substrate.

[0007]

In order to achieve this object,
In the present invention, by the leaf spring and the rod-shaped mounting member,
A radiator fixing structure for a semiconductor device which achieves external heat radiation by elastically contacting and holding a semiconductor device with a plate-shaped heat radiating member (heat sink), wherein the semiconductor device is provided with a resin case serving as an exterior thereof, Toward the contact holding surface of the heat dissipation member,
A screw hole for attachment is formed through the plate spring. The leaf spring has an elastic contact portion on one end, which is opposite to the contact holding surface and elastically contacts the elastic surface of the resin case. A U-shaped curved portion is formed, and a pair of insertion holes that are aligned with the screw hole are formed in the curved portion, and the mounting member penetrates the insertion hole, and It is characterized by being engaged.

According to an embodiment of the present invention, the rod-shaped fixing member has a head for pressing around the fixing member insertion hole of the leaf spring member, an insertion hole of the leaf spring member, a screw hole of the semiconductor device, and a heat radiation. It is preferable to have an expansion / contraction tip so as to prevent the container from coming off when the container is inserted in the order of the mounting holes and penetrated.

[0009]

Embodiments according to the present invention will be specifically described below with reference to the drawings. FIG.
1 is a side sectional view showing an embodiment of the present invention, and FIG. 2 is a front view. 3A is a side view of the leaf spring member 7, and FIG. 3B is a plan view.

1 and 2, reference numeral 1 denotes a resin case of a semiconductor device, 2 denotes a terminal, 5 denotes an external radiator, 6 denotes a substrate,
Reference numeral 7 denotes a holding plate spring, 8 denotes a rod-shaped fixing member, and 9 denotes an expanding / reducing head of the rod-shaped fixing member 8. 3A and 3B, reference numeral 7a denotes a U-shaped curved portion for pressing a heat sink mounting hole portion of the semiconductor device, 7b denotes a leaf spring portion for pressing a central portion of a resin case, and 7c and 7d denote rod-shaped holders. It is a hole through which a member is penetrated.

The method of attaching an external radiator to a semiconductor device according to the present invention will be described below. As shown in FIG. 1, a rod-shaped attachment member 8 has a head 8a and an expansion / contraction tip 8b. Is formed with a groove. Therefore, it is possible to reduce the thickness by the width of the groove, and when it is passed through a hole of a size that can be penetrated at the time of reduction, after the tip portion passes through the hole, it expands to the original thickness, and it stops retaining. Become.

In a state where the leaf spring 7, the semiconductor device 1, and the external radiator 5 are stacked, the rod-shaped mounting member 8 is inserted into the hole 7 of the leaf spring 7.
c, 7d, the holes of the radiating fins of the semiconductor device, and the mounting holes of the external radiator are pierced in this order, and the head 8a is pushed and inserted until the enlarged / reduced distal end 8b is prevented from falling off by the external radiator. As a result, as shown in FIG.
Is attached to the external radiator 5. After that, the terminal 2 is inserted into the through hole of the substrate 6 and soldered.
The mounting on the board is completed.

Here, the rod-shaped mounting member 8 is set to such a length that the enlarged / reduced head cannot be prevented from falling out unless the U-shaped curved portion 7a of the leaf spring 7 is crushed to some extent when the penetration is performed. I have. Therefore, in the process of inserting the rod-shaped mounting member 8, the leaf spring portion 7 b functions to press the semiconductor device 1 against the external radiator 5. Due to this pressing force, the back surface of the semiconductor device 1 and the external radiator 5 come into close contact with each other,
The required heat dissipation is obtained.

The leaf spring 7 has a required shape and dimensions such that the arc-shaped contact point is located at a position where the semiconductor device 1 is pressed, that is, substantially at the center of the resin case.

[0015]

As described above, according to the present invention, when the semiconductor device is mounted on the external radiator, the plate spring, the semiconductor device, and the external radiator are arranged in a predetermined arrangement, and, for example, a rod-shaped mounting member having an expansion / contraction tip portion. Is inserted into each hole, and pushed in until the enlarged / reduced tip portion stops retaining, and is locked in the insertion hole, so that the leaf spring presses the center of the resin case of the semiconductor device. like,
Mechanical stress is not concentrated on one side of the semiconductor device, and troubles such as chip cracks can be prevented.

Further, when mounting, it is only necessary to push the rod-shaped mounting member into the insertion hole until it stops, so that the efficiency of the operation is greatly improved as compared with screwing.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a front view showing the embodiment of the present invention.

FIG. 3 is a side view (a) and a front view (b) of the leaf spring member 7;

FIG. 4 is a side sectional view showing a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor device 2 terminal 3 heat sink screw hole 4 mounting screw 5 external radiator 6 substrate 7 leaf spring member 7a U-shaped curved portion 7b semiconductor device body pressing portion 7c, 7d rod-shaped mounting member insertion hole 8 rod-shaped mounting member 8a Head 8b Expansion / contraction tip

Claims (3)

[Claims] 1. A radiator fixing structure for a semiconductor device which achieves external heat radiation by elastically contacting and holding a semiconductor device with a plate-shaped heat radiating member (heat sink) by a plate spring and a rod-shaped mounting member. In the semiconductor device, a resin case serving as an exterior thereof has a screw hole for attachment formed therethrough toward a contact holding surface of the heat radiating member, and the leaf spring is provided on a side opposite to the contact holding surface. An elastic contact portion elastically contacting the elastic surface of the resin case is formed on one end side, and U
Forming a pair of insertion holes that are aligned with the screw holes, and the mounting member penetrates the insertion holes and engages with the screw holes. A radiator fixing structure for a semiconductor device, wherein the radiator is fixed to a semiconductor device. 2. The radiator fixing structure for a semiconductor device according to claim 1, wherein said plate spring has an elastic contact portion elastically contacting with an elastic surface of said resin case. 3. The rod-shaped mounting member has a head at its base end, which is engaged with the leaf spring, and a hook at its front end, which engages with the outer edge of the screw hole. The radiator fixing structure for a semiconductor device according to claim 1, wherein a split groove for elastic deformation is formed so as to pass through the screw hole.