JPS60206141A - Resin sealing metallic mold - Google Patents

Abstract

PURPOSE:To prevent a gap between upper and lower metallic molds as well as a burr in a formed product from happening by a method wherein, in resin sealing metallic molds of a semiconductor product, a post provided in the guide of lower mold is depressed into the lower mold during molding operation. CONSTITUTION:A bush 34 is fixed to an upper mold base 31 while another bush is mounted in the hole 35 of lower mold 32 to make a post 37 free-slide up and down. The top end of spring 39 abuts against the bottom end of post 37 to lift the post upward. In the molding process, the upper and lower molds are aligned by means of inserting the tapered surface of post 37 into the tapered surface of bush 34 before the opposite surfaces B of upper and lower molds come into contact with each other. When both metallic molds are pressurized to make the opposite surfaces B come into contact with each other, the post 37 is depressed into the lower mold base 32 against the elastic energy of spring 39 for molding operation. Through these procedures, any gap between the upper and lower metallic molds may be prevented from happening since the overall molding forces are exerted on the opposite surfaces B with the guide of lower mold having no influence upon the molding operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a resin sealing mold used in the assembly process of semiconductor devices.

[Technical Background of the Invention] In the manufacturing process of semiconductor devices, a mold is used to seal the circuit with resin after the circuit is completed. The occurrence of was becoming a problem. Conventionally, this mold has been used, for example, in figures 1 to 3.
It was configured as shown in the figure. In FIGS. 1 to 3, 11 is an upper mold, and 12 is a lower mold. The upper mold 11 has an upper mold base 14 fixed to an upper mold spacer block 13, and the lower mold 12 has a lower mold base 1 fixed to a lower mold spacer block 15.
6 is fixed. This upper mold base 14 and lower mold base 1
A semiconductor device in a frame state is sandwiched between G and G. In FIGS. 1 and 2, A indicates a mating surface between the upper mold base 14 and the lower mold base 16.

In addition, in Fig. 3, the right half shows the cross-sectional state of the upper mold base 14, and the left half shows the cross-sectional state of the lower mold base 16. It is being At each of the four corners surrounding the joint between the upper mold base 14 and the lower mold base 16, the upper mold base 1 is placed opposite to each other.
A bushing 18 is provided on the 4 side, and a post 19 that fits into the bushing 18 is provided on the lower die base 16 side. That is, when clamping the mold, positioning is performed by fitting the posts 19 into the bushes 18 from about 10 minutes before the mating surfaces A of the upper mold 11 and the lower mold 12 come into contact with each other,
After that, the process moves to mold clamping.

[Problems with blue slip technology] Conventionally, in the above mold, as a measure to prevent the occurrence of resin flakes on the frame surface, attention was paid to the cavity part and the overall flatness and parallelism were improved. This was done by letting people know.

However, in this mold, when the mold is clamped, 200
Since they are used after being heated to nearly 100°C, simply improving parallelism and flatness was not sufficient as a countermeasure against resin flakes. That is, the pitch between the guides before heating (a in Fig. 1,
The accuracy of (denoted by b) is, for example, 1. Inside, the gap between the post 19 and the bushing 18 (shown as b in Figure 4)
is within 0.02 ar, but when heated to nearly 200 degrees, the pitch between the guides is 0.001 trun/1 ar
The upper mold 11 and the lower mold 12 are positioned in the expanded state. Further, although the upper die base 14 and the lower die base 16 are made of the same material and have the same shape, there is a difference in elongation between the two due to differences in the processing locations. For this reason,
There are so-called galling marks between the post 19 and bush 18 of the mold that has been used to some extent, and as a result, the upper and lower mating surfaces A
A gap was created between the two, which was one of the causes of resin flakes.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to prevent the formation of gaps between the upper and lower mating surfaces due to heating during mold clamping, and to prevent the formation of gaps in molded products. It is an object of the present invention to provide a resin sealing mold capable of preventing the occurrence of resin flakes.

[Summary of the Invention] The present invention provides a resin sealing mold for resin-sealing a semiconductor product by clamping a first mold and a second mold. a bushing having a tapered part on the inner wall surface of the tip thereof and fixed to the guide part of the first type; and a bushing provided to the guide part of the second type. a hole, a post having a tapered part on the outer wall surface of the tip to fit into the tip of the bushing, and slidably provided in the hole of the second type; It comprises a spring that biases the post in the direction of the bushing, and an engaging part that is provided on the post and the second mold and prevents the post from coming off from the second mold, and the second mold. The post is fitted into the bush before the mating surfaces of the two molds come into contact with each other, and the post is then sunk into the second mold at the same time as the molds are clamped.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 5 shows the configuration of the guide portion of the mold according to the present invention, and as in the conventional mold, the guide portions are provided at each of the four corners around the mating portion of the upper mold and the lower mold. 18
In FIG. 1, 31 is an upper die base fixed to an upper die spacer block (not shown), and 32 is a lower die base fixed to a lower die spacer block 33. A bushing 34 is fixed to the surface of the upper mold base 31 facing the lower mold base 32. An inner wall surface 34'a at the tip of this bushing 34 is formed into a tapered shape. On the other hand, a hole 35 is provided in the lower die base 32 so as to face the bush 34 . A gunmetal bushing 36 is mounted within this hole 32. A post 37 is vertically slidable within this gunmetal bushing 36. The tip end 37a of this post 37 is also formed in a tapered shape, and can be fitted into the tapered part of the bush 34. A hole 38 having a smaller diameter than the circumferential hole 35 is provided in the lower mold spacer block 33 in succession to the hole 35, and a base end portion of a spring 39 is fixed in the hole 38. The tip of the spring 39 comes into contact with the lower surface of the post 37, and its elastic force urges the post 37 upward. The total load capacity of these three springs is, for example, 1 t, and in a state where no load is applied, when the upper and lower molds are overlapped, they support the upper mold. Furthermore, stepped portions 37b and 36 are provided at the lower end of the post 37 and the upper end of the gunmetal bushing 3G, respectively.
a is provided, and the two engage to prevent the post 37 from separating from the lower mold base 33. Note that B is a mating surface between the upper mold and the lower mold.

In the above mold, the spring 39 is set so that the gap (indicated by d in FIG. 5) between the post 37 and the gunmetal bushing 36 is 1M when the mold is opened. Thus, during mold clamping, the tapered surface of the is flat front post 37, with which the mating surfaces B of the upper and lower molds come into contact, is fitted into the tapered surface of the bushing 34 and positioned. After that, apply 100 to 200 to both molds.
A load of t is applied, the mating surfaces B come into contact, and the post 37 resists the elastic force of the spring 39 to push against the lower die base 3.
2, and the mold is clamped. After that, resin sealing is performed.

In conventional molds, the kites (posts and bushings) that were originally intended for positioning are involved even after the mold has been clamped due to the influence of heating, resulting in gaps between the upper and lower mating surfaces, which causes resin flaking. It was causing this. On the other hand, in the mold of the present invention, the post 37 sinks at the same time as the mold clamping, so the guide does not take part in the mold clamping. For this reason,
All of the mold clamping force is applied to the upper and lower mating surfaces B, and no gaps are created.2 Therefore, no resin flakes occur in the molded product.

In addition, since the upper mold is supported by the elastic force of the spring 39, the upper mold does not come into contact with the cavity part due to its own weight before applying the mold clamping force, and therefore the product (frame)
There will be no scratches.

[Effects of the Invention] As described above, according to the present invention, no gap is generated between the upper and lower mating surfaces due to the influence of heating during mold clamping, and therefore a molded product without resin flash can be obtained.

[Brief explanation of the drawing]

Figure 1 is a side view showing the configuration of a conventional resin sealing mold;
The figure is a front view of the same, Figure 3 is a sectional view showing the same plane state, and Figure 4 is a sectional view showing the same plane state.
The figure is a cross-sectional view showing the guide portion of the mold, and FIG. 5 is a cross-sectional view showing the guide portion of the resin-sealed mold according to an embodiment of the present invention. 31... Upper mold base, 32... Lower mold base, 34.
...button, 35...hole, 36...gunmetal bush, 37...bost. 39...Spring. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In a resin sealing mold for resin-sealing a semiconductor product by clamping the first mold and the second mold, a guide provided opposite to the first mold and the second mold, respectively. a bush having a tapered portion on the inner wall surface of the tip and fixed to the guide portion of the first type; a hole provided in the guide portion of the second type; and a bush having a tapered portion on the inner wall surface of the tip; a post having a tapered portion that fits into the tapered portion of the bushing and slidably provided in the hole of the second mold; and a spring disposed in the hole that urges the post in the direction of the bushing. and an engaging portion provided on the post and the second mold to prevent the boss from separating from the second mold, and before the mating surfaces of the two molds come into contact. A resin-sealed mold characterized in that the post fits into the bushing, and the post sinks into the second mold at the same time as the mold is clamped.