JPH0230837Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an apparatus for manufacturing semiconductor devices, and in particular to a stirring device for blending a solder member well with a substrate prior to mounting a semiconductor element on the substrate.

[Background technology]

Generally, in a semiconductor device, as shown in FIG. 1, a semiconductor element B is fixed to a substrate A such as a heat sink using a solder member c, and the electrodes of the semiconductor element B and leads D are connected using thin metal wires E. The main portion including the semiconductor element B is molded and covered with a resin material F.

In this semiconductor device, a nickel plating layer is formed on the entire surface of the substrate A, and a silver plating layer is further formed on the nickel plating layer on the fixed portion of the semiconductor element B by a partial plating method. The solder member C exhibits good conformability to the substrate A. For this reason, the semiconductor element B can be securely fixed to the substrate A without adversely affecting the characteristics.

However, in recent years, the cost of semiconductor devices has tended to increase due to the high prices of precious metals such as silver, so it is possible to omit the silver plating layer and directly fix the semiconductor element B to the nickel plating layer. Although these methods have been studied, the following problems have not resulted in fully satisfactory results.

That is, the nickel plating layer does not have as good compatibility with the solder member C as the silver plating layer does, so before fixing the semiconductor element B to the substrate A, the solder member C is attached to the substrate A. It is necessary to forcibly adapt it to the Nickelmetsuki layer.

For this purpose, a stirring rod made of a heat-resistant material such as that disclosed in Japanese Patent Publication No. 57-24928 is used, and the lower end of the rod is pressed against the molten solder material and rotated. However, the temperature of the solder member tends to drop during stirring, making it impossible to obtain sufficient effects.

Therefore, for example, as shown in FIG.
It has been proposed to integrate the body part Ga and the stirring part Gb at the center by a connecting part Gc, but in reality, the board A is placed on the heating rail H and the molten solder is heated. When the stirring bar Gb is pressed against the member C and rotated, as shown in Fig. 3, a part of the solder member C that is difficult to fit in with the substrate A tends to form in the center, and even if the semiconductor element B is fixed, the thermal resistance characteristics will deteriorate. It is significantly impaired and practical problems remain.

We investigated the cause of this and found that because the main body Ga and the stirring part Gb are connected at the center by an extremely short connecting part Gc, the heat of the solder member C is transferred to the stirring part Gb and the connecting part during stirring. Main body Ga through Gc
It has become clear that the compatibility of the center portion of the solder member C with the substrate A is impaired as a result of the solder member C being easily moved, and the solder member C being not sufficiently stirred at the center of rotation.

However, if the rotation speed of the stirring rod G is increased in order to improve the compatibility of the solder member C with the substrate A, the solder member C will be blown off by the stirring rod G and will spread more than necessary. On the contrary, the fixation of the semiconductor element B is impaired, which is not preferable.

[Disclosure of invention]

Therefore, the purpose of the present invention is to provide a semiconductor device manufacturing apparatus that has a simple configuration that prevents the solder material from spreading more than necessary even when the rotational speed of the stirring bar is increased, and that can effectively improve the compatibility with the substrate. It's about doing.

The feature of the present invention is that the lower end of the stirring rod made of a heat-resistant material is placed on the substrate and is pressed against the molten solder material and rotated to blend the solder material with the substrate. A ring-shaped protrusion is formed on the periphery of the lower end surface, and stirring blades are formed in the recess surrounded by the protrusion.

According to this invention, the solder material is stirred by the blades within the space surrounded by the protrusion of the stirring rod, so even if the rotation speed of the stirring rod increases, the solder material will not spread more than necessary. Never. For this reason, the semiconductor element can be fixed to the substrate with a required amount of solder material, and sufficient fixation can be ensured.

Further, since the solder member is stirred by the blade within the space surrounded by the protrusion, the overall compatibility of the solder member with the substrate can be made good. Therefore, when a semiconductor element is fixed, its thermal resistance can be improved.

[Best form for implementing the idea]

Next, an embodiment of the present invention will be described with reference to FIGS. 4 and 5.

In the figure, 1 is a heating rail, above which a stirring device 2 is disposed. This stirring device 2 includes a wire 3 extending from a drive system such as a motor, a bottomed cylindrical support member 4 fixed to the end of the wire 3, and a stirring device fixed by inserting the upper end into the support member 4. It consists of a rod 5. The stirring rod 5 is made of ceramic, for example, and has a ring-shaped protrusion 6 formed at the peripheral edge of its lower end surface. A plurality of arc-shaped blades 8 are formed in the recess 7 surrounded by the protrusion 6. In particular, the protrusion 6 and the lower end surfaces of the blades 8 are formed to be approximately on the same plane, but the blades 8
The lower end surface of the protrusion 6 can also be made lower than the lower end surface of the protrusion 6.

Next, a method of stirring the solder member will be explained with reference to FIG. 6. First, a substrate A made of copper with a nickel plating layer formed on the entire surface is placed on the heating rail 1, and a tin-antimony (Sn-Sb) based solder material C is supplied to the portion of the substrate A where the semiconductor element is to be fixed. do. Then, the substrate A is intermittently transferred in a fixed direction, and during this time the solder member C becomes molten. When the substrate A is moved to a predetermined position and stopped, the stirring device 2 rotates at a rotation speed of about 2 to 3 times per second and descends, placing the solder member C in the space surrounded by the protrusion 6. Store it. In this state, the solder member C located in the space (recess) 7 is forcibly rotated by the plurality of blades 8. As a result, the solder member C adapts to the nickel plating layer of the substrate A.

Since the solder member C is stirred while being held in the space surrounded by the protrusion 6 of the stirring rod 5, it is possible to prevent the solder member C from spreading more than necessary, and it is possible to prevent the solder member C from spreading more than necessary. can improve fixation.

Furthermore, since the solder member C is forcibly stirred by the blades 8 in the space 7, the compatibility with the substrate A can be made good throughout. Therefore, when the semiconductor element is fixed, deterioration of thermal resistance characteristics can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the semiconductor device, FIG. 2 is a partial sectional view for explaining the method of stirring the solder material, FIG. 3 is a plan view showing how the solder material is adapted to the substrate, and FIG. 4 5 is a side sectional view showing an embodiment of the present invention, FIG. 5 is a bottom view of FIG. 4, and FIG. 6 is a partial sectional view for explaining a method of stirring a solder member. In the figure, A is a substrate, C is a solder member, 2 is a stirring device, 5 is a stirring rod, 6 is a protrusion, 7 is a recess (space), and 8 is a blade.

Claims (1)

[Scope of utility model registration request] The lower end surface of the stirring rod made of a heat-resistant material is placed on the substrate and rotates while pressing against the molten solder material to blend the solder member onto the substrate, the peripheral edge of the lower end surface of the stirring rod being rotated. 1. An apparatus for manufacturing a semiconductor device, characterized in that a ring-shaped protrusion is formed in the protrusion, and a stirring blade is formed in a recess surrounded by the protrusion.