JPH0590460A - Method for manufacturing semiconductor device - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the thermal stress of power semiconductor devices and simplify the bonding to metal insulating substrates. [Structure] A solder material 14 is pressure-bonded to both surfaces of the heat spreader 12 by a solder clad technique, the heat spreader 12 is mounted on a metal insulating substrate 13, and the power semiconductor element 11 is mounted on the heat spreader 12. These are put into a heating step, and the power semiconductor element 11, the heat spreader 12, and the metal insulating substrate 13 are soldered at the same time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a power semiconductor device, and more particularly to a process for joining a power semiconductor element and a heat sink and a process for joining a heat sink and a metal insulating substrate.

[0002]

2. Description of the Related Art FIG. 3 is a process flow chart of a conventional semiconductor device, FIG. 4 is a schematic view showing a conventional semiconductor device manufacturing method, and FIG. 5 is a sectional view of the semiconductor device.

A conventional method of manufacturing a resin-sealed semiconductor device will be described with reference to FIG.

[1] In the die-bonding process, as shown in FIG. 4, a cream solder 2 (Ag / Su / Pb) 3 is screen-printed on a heat spreader 1 made of Cu material, and a power semiconductor element 3 made of Si material is formed thereon. Set (S
01).

[2] In the first reflow step, the die-bonded members are passed through an infrared heating type reflow furnace to be soldered and joined (S02).

[3] In the component mounting step, cream solder 6 is screen-printed on the electrode 5 on the metal insulating substrate 4,
A heat spreader on which the power semiconductor element 3 is mounted is mounted (S03).

[4] In the second reflow step, the metal insulating substrate 4 on which the heat spreader 1 is mounted is soldered and bonded through an infrared heating type reflow furnace (S0).
4).

[5] In the cleaning step, the material passed through the above steps is washed. Here, the reason why the cleaning is necessary is that the cream solders 2 and 6 use the flux of the rosin thread (S05).

[6] In the subsequent steps, as shown in FIG. 5, the power semiconductor element 3 and the electrode 5 on the metal insulating substrate 4 are wired by the aluminum wire 7 in the wire bonding step (S).
06), the electrode 5 on the metal insulating substrate 4 in the terminal attaching step
Then, the tab terminal 8 is set and joined (S07).

[7] Also, in the framing process, the outer frame case 9
Is bonded to the metal insulating substrate 4 (S08), and then the silicone gel agent 10 for protecting the power semiconductor element 3 and the electrode 5 on the metal insulating substrate 4 is injected and heat-cured (S8).
09), and then an epoxy resin 11 for isolating the inside and the outside of the semiconductor device is injected and heat curing is performed (S10),
Completed as shown in FIG. After that, an inspection is performed (S1
1) The product is shipped (S12).

[0011]

In the manufacturing method shown in the process flow chart of FIG. 3, the power semiconductor element 3 is soldered and bonded on the heat spreader 1, so that the power semiconductor element 3 is subjected to the heat reflow process again. It will add stress.

At this time, since the heat spreader material, the solder material, and the power semiconductor element material have different thermal expansion coefficients, the power semiconductor element 3 is distorted and sometimes destroyed, which results in high quality and high reliability. It was difficult to realize.

Further, the process is complicated, which is an obstacle to the reduction of manufacturing cost.

In view of the above problems, the present invention aims to provide a method of manufacturing a semiconductor device which can reduce the thermal stress of a power semiconductor element to reduce the stress between members and simplify the joining process thereof. And

[0015]

As shown in FIGS. 1 and 2, a means for solving the problems according to the present invention is a power semiconductor element 11, a heat radiating plate 12 for cooling the power semiconductor element 11, and a heat radiating plate 12.
In a method for manufacturing a semiconductor device, in which a metal insulating substrate 13 for cooling a semiconductor is bonded to each other, before the bonding, the heat sink 1
The soldering material 14 is joined to both surfaces of the two, the power semiconductor element 11 is brought into contact with the soldering material 14 on one side, and the metal insulating substrate 13 is brought into contact with the soldering material 14 on the other side, and these are heated and simultaneously soldered and joined. It is a feature.

[0016]

In the means for solving the above problems, the solder material 14 is pressure-bonded to both surfaces of the heat dissipation plate 12 by the solder clad technique to form the heat dissipation plate 1.
2 is mounted on the metal insulating substrate 13, and the power semiconductor element 11 is mounted on the heat dissipation plate 12. These are put into a heating step, and the power semiconductor element 11, the heat sink 12 and the metal insulating substrate 13 are soldered at the same time.

[0017]

1 is a schematic diagram showing the operation of a method of manufacturing a semiconductor device showing an embodiment of the present invention, and FIG. 2 is a process flow chart thereof.

As shown in the figure, the semiconductor device of this embodiment includes a power semiconductor element 11, a heat radiating plate 12 for cooling the power semiconductor element 11 (hereinafter referred to as a heat spreader), and a metal insulating substrate 13 for cooling the heat spreader 12. And
They are joined to each other via the solder material 14.

The power semiconductor element 11 is a Si material, the heat spreader 12 is a Cu material, and the solder material 14 is Ag /
This is the same as the conventional example in which the Su / Pb material or the like is used.

In FIG. 1, 15 is a metal base of the metal insulating substrate 13, 16 is an insulating layer, and 17 is an electrode pattern made of copper foil.

Next, a method of manufacturing the above semiconductor device will be described with reference to FIG.

First, as a preparatory step, the solder material 14 is pressure-welded to the entire regions of both surfaces of the heat spreader 12 by using an existing clad technique, in particular, a cold rolling pressure welding method.

Then, in the die bonding process, the heat spreader 12 having the solder material 14 on both sides is placed on the electrode pattern 17 on the metal insulating substrate 13. Further, the power semiconductor element 11 is placed on the heat spreader 12 (S21).

Next, in the reflow step, the above semiconductor device is passed through an infrared heating type reflow furnace and soldering is performed. However, since the solder material 14 is formed in the entire region of the heat spreader 12, it is not necessary to melt and spread the solder itself by the flux at the time of reflow, and thus the flux is unnecessary. Therefore, the inside of the furnace is limited to the reducing atmosphere, and the conventional cleaning process is omitted here (S
22).

The following is the same as the conventional process, and the power semiconductor element 11 and the electrode pattern 17 on the metal insulating substrate 13 are connected by an aluminum wire in the wire bonding process (S2).
3) In the terminal attaching step, tab terminals are set and bonded to the electrodes 17 on the metal insulating substrate 13 (S24). In the framing process, the outer frame case is bonded to the metal insulating substrate 13 (S2
5) In the gel injection step, a silicone gel agent for protecting the power semiconductor element 11 and the electrode 17 on the metal insulating substrate 13 is injected and heat-cured (S26). Epoxy resin 9 is injected to shield the semiconductor device from the outside and heat-cured (S27) to complete the semiconductor device. Then, the semiconductor device goes through an inspection process (S28) and is shipped (S29).

By the above manufacturing method, the reflow process, which has been conventionally two steps, is performed simultaneously, and the heating process is only required once, so that the heat spreader 12 can be prevented from being oxidized and the thermal stress applied to the power semiconductor element 11 can be reduced. The reliability of the power semiconductor element 11 itself can be improved, and the quality and performance of the power semiconductor device can be improved.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

[0028]

As is apparent from the above description, according to the present invention, conventionally, only two reflow steps are required, and the steps can be simplified and the cost can be reduced at the same time.

Further, since the number of times of heating in the reflow step is reduced, the thermal stress applied to the power semiconductor element is reduced, the element destruction failure due to heating is reduced, the manufacturing yield is improved, and the quality and reliability are high. If it becomes possible to supply the above semiconductor device, there will be an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an operation of a method of manufacturing a semiconductor device showing an embodiment of the present invention.

FIG. 2 is a process flow chart of the same.

FIG. 3 is a process flow chart showing a conventional method for manufacturing a semiconductor device.

FIG. 4 is a schematic view showing the same operation.

FIG. 5 is a completed view of a general semiconductor device.

[Explanation of symbols]

 11 power semiconductor element 12 heat sink 13 metal insulating substrate 14 solder material

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor device in which a power semiconductor element, a heat dissipation plate for cooling the power semiconductor element, and a metal insulating substrate for cooling the heat dissipation plate are bonded to each other, and before the bonding, the heat dissipation plate is provided. Of the semiconductor device, wherein the solder material is joined to both surfaces of the power semiconductor element, the solder material on one side is brought into contact with the metal insulating substrate on the solder material on the other side, and these are heated and soldered at the same time. Production method.