JPH05162175A - Mold device for resin encapsulation - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to prevent a resin from being left in intimate contact with an air escape groove in a mold device for resin encapsulation. [Structure] A cavity 1 and an air escape groove 2 are provided, and the cavity 1 is for molding a resin-sealed molded product,
The air escape groove 2 is provided in at least one of the lower mold 10 and the upper mold 20 that abut against each other, and the air escape groove 2 has a concave portion 3a carved in a dividing surface 3 that intersects at least one side wall of the cavity 1. , Is formed so as to be surrounded by the abutting surface 4 that abuts and faces each other, and the inner surface is subjected to a non-adhesive treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealing mold device, and particularly to a mold device used for sealing a resin-sealed semiconductor device so that the resin does not remain in close contact with the air escape groove. The present invention relates to a mold device for resin sealing.

In recent years, the progress of semiconductor devices has been remarkable, and the number of semiconductor devices produced has increased dramatically as the fields of use have expanded. And
The mass production of this semiconductor device largely depends on the manufacturing technology of a series of manufacturing processes from the wafer stage to the completion of the product as a semiconductor device.

The manufacturing process of a semiconductor device can be divided into a pre-process and a post-process. The pre-process is from the wafer stage to the formation of many fine elements, and the post-process is
It is from cutting the wafer into chips to finishing the product. The post-process is divided into an assembly process and an inspection process.

In the assembly process, the sealing of the chip is a so-called package for protecting the element and taking out the lead-out terminal. Although various forms and methods are adopted for the package, a plastic package by resin molding to which a molding technique is applied is often used because of high manufacturing efficiency and low cost. Further, there is still room for study on the efficiency of the resin encapsulation technology and the encapsulation device for carrying out it.

[0005]

2. Description of the Related Art For example, in a resin sealing of a semiconductor device, a frame-shaped supporting member called a lead frame is used, a chip is mounted on a stage of the lead frame, and a gold wire is attached to a terminal portion called an inner lead. Wire-bonded by etc. Resin sealing is performed by a kind of insert molding in which this lead frame is set in a sealing die and a sealing resin is poured.

By the way, the resin encapsulation of the semiconductor device needs to be carried out with high precision and low molding pressure, like other electronic parts. Therefore, transfer molding using a thermosetting resin such as an epoxy resin is used. Then, it is generally performed by a low-pressure encapsulation molding method capable of particularly low-pressure molding for electronic parts.

FIG. 3 is an enlarged perspective view of a part of an example of the resin sealing mold device. In the figure, 1 is a cavity,
2 is an air escape groove, 7 is a resin, 8 is a molded product, 9 is a mold device, 10 is a lower mold, 11 is a cull, 12 is a runner, 13 is a gate, 20
Is an upper die, 21 is a pot, 22 is a sprue, and 30 is a lead frame.

The mold device 9 exemplified here is a mold used for sealing electronic parts such as semiconductor devices, and is a mold for low pressure transfer molding using a thermosetting epoxy resin molding material. This is an example. The upper mold 20 abuts on the lower mold 10. Then, for example, when a semiconductor chip is resin-sealed to make a plastic package type semiconductor device, the lead frame on which the chip is mounted is mounted.
30 is carried by a holder called a loading frame, and is sandwiched between two molds 10 and 20, and resin sealing is performed.

The upper die 20 is a pot for heating the injected resin 7 to melt and soften it, plasticize it and push it into the die.
21 (materials room) is provided. Below the pot 21, a cull 11 is provided in the lower mold 10 through an injection hole called a sprue 22.

By the way, in the case of resin sealing of electronic parts including semiconductor devices, so-called multi-cavity picking is performed in which a large number of molded products 8 are obtained by one molding. Therefore,
From the cull 11, for example, two or four, or a runner 12 that is radially expanded by branching from the middle is provided. This runner 12, which is also called a runner, is a path through which the resin melted like letters flow. And runner 12
A large number of cavities 1, such as 20 cavities and 50 cavities, are arranged side by side through the gate 13 at the tip of the.

The concave portion (cavity in a narrow sense) and the convex portion (core) which form the cavity 1 are appropriately provided in the lower mold 10 and the upper mold 20 according to the shape of the molded product, and the two molds 10, 20 are provided. When they are abutted against each other, they are projected upward or downward to give a desired shape of the molded product 8.

Resin 7 which is heated and melted in a pot 21 to be plasticized
Is extruded into the cull 11 through the sprue 22 while being pressurized by a plunger (not shown). Then, the resin 7 passes through the runners 12 radially branched from the cull 11 and is filled in the respective cavities 1 through the gates 13 branched further into small branches from the runners 12.

By the way, the thermosetting resin molding process is carried out through three steps of plasticizing, shaping and curing. Then, applying these three steps to the transfer molding method, first, in the first step, the solid resin 7 shaped into pellets is heated in the pot 21 and plasticized to lower the viscosity. Easy to flow, nozzle-shaped sprue 22
It is once discharged up to Cull 11 through. Then, the cavity 1 is filled through a plurality of runners 12. In the second stage, the resin 7 is sufficiently filled in every corner of the cavity 1 to reach a predetermined molding pressure, and a desired shape according to the shape of the cavity 1 is imparted. In the third stage, the thermosetting resin 7 is cured by a chemical reaction such as condensation polymerization or addition polymerization.

In the transfer molding, the resin 7 spreads over all of the many cavities 1, and a predetermined molding pressure is uniformly applied to all the cavities 1, and after the second step is completed, the third step of curing is performed. It is desirable to start. In order for the resin 7 to reach every corner of the cavity 1, it is essential to completely remove the air generated in the cavity 1 and the gas generated from the resin 7.

Therefore, an air escape groove 2 which is also called an air vent is provided in a part of the cavity 1. The air escape groove 2 may be provided at a place where air and gas are most unlikely to escape, and is generally provided at a position farthest from the gate 13 on the dividing surface of the mold.

The air escape groove 2 is designed so that only the air and gas components escape and the resin component does not flow out as a flash. For example, the depth is 30 to 50 μm and the width is 3 to 5.
The groove is about mm.

[0017]

As described above, in the transfer molding performed by resin sealing of the semiconductor device, the cavity 1 is provided with the air escape groove 2 for letting air or gas escape. And this air escape groove 2
It is unavoidable that the resin 7 becomes a flash and gets into the resin to some extent.

By the way, the abutting surfaces of the die unit 9 are plated with hard chrome generally called hard chrome. Although this hard chrome has a high abrasion resistance, it has a strong adhesiveness to, for example, an epoxy resin molding material and does not have a good releasability.

On the other hand, the epoxy resin molding material that is often used for resin encapsulation has excellent adhesiveness as it is used as an adhesive material, and also has good adhesiveness to the lead frame 30 and the like.

Therefore, the molded product 8 itself having a large thickness formed in the cavity 1 can be released from the mold relatively easily, but the resin 7 that has entered thinly into the air escape groove 2 adheres and sticks. It often happens that they are left without being released.

If the residue of the adhered resin 7 is not removed, defects such as voids (cavities) and chippings will occur in the molded product 8, or a space will be taken to separate the adhered resin 7, resulting in work efficiency. There was a problem of deterioration.

Therefore, an object of the present invention is to provide a resin-sealing mold device which is subjected to a non-adhesive treatment so that the resin does not remain in close contact with the air escape groove.

[0023]

[Means for Solving the Problems] The above-mentioned problem has a cavity and an air escape groove, and the cavity is for molding a resin-sealed molded product, and the lower mold is abutting against each other. And the air escape groove is provided in at least one of the upper molds, and the air escape groove is surrounded by an abutting surface that abuts against a recess carved in a dividing surface that intersects at least one side wall of the cavity. This is solved by a resin-sealing mold device configured so that it is formed with a non-adhesive treatment on its inner surface.

[0024]

In the conventional mold device for resin encapsulation, the resin enters into the air escape groove, and the resin remains in intimate contact and remains peeled off. However, in the present invention,
The inner surface of the air escape groove is non-adhesive processed so that the resin that has entered does not adhere.

Then, when the molded product is taken out from the cavity, the resin which has entered the air escape groove and hardened can also be peeled off and taken out at the same time, so that the efficiency of the resin sealing step and the reduction of defects can be achieved.

[0026]

1 is an enlarged perspective view of a part of an embodiment of the present invention, and FIG. 2 is an enlarged perspective view of a main portion of another embodiment of the present invention. In the figure, 1 is a cavity, 2 is an air escape groove,
3 is a dividing surface, 3a is a concave portion, 4 is an abutting surface, 5 is a release film, 6 is a nest, 7 is resin, 8 is a molded product, 10 is a lower mold, 20 is an upper mold,
30 is a lead frame.

Embodiment 1 In FIG. 1, a cavity 1 is for shaping a package of a resin-sealed semiconductor device, for example. In the case where the leads are projected from the side wall of the package, the cavity 1 is carved so as to face both the lower mold 10 and the upper mold 20. Then, the lead frame 30 on which the chip is mounted is sandwiched between the lower mold 10 and the upper mold 20, and resin sealing is performed.

The air escape groove 2 is often provided as a recess 3a in the dividing surface 3 that intersects at least one side wall of the cavity 1 of the lower mold 10. The recess 3a has a depth of 30 μm.
The air escape groove 2 is formed by being carved to have a width of about m and a width of about 5 mm, and is surrounded by the recess 3a and the abutting surface 4 of the upper die 20 facing the recess 3a.

The inner surface of the concave portion 3a forming the air escape groove 2 and the abutting surface 4 that abuts the concave portion 3a are covered with a release film 5 made of, for example, baking coated with fluororesin or silicon resin. It is worn.

In this way, the resin sealing is completed and the upper and lower molds are
When releasing 10 and 20 by releasing the molded product 8, the air escape groove 2
The resin 7 that has flowed into the mold will not be left in close contact, and can be released as a flash together with the molded product 8.

Embodiment 2 In FIG. 2, a fluorine resin resin insert 6 having a recess 3a is fitted so as to be continuous with the side wall of the cavity 1 of the lower mold 10. Further, a fluorine resin nest 6 is fitted on the abutting surface 4 of the upper mold 20 facing each other.

The fluorine-based resin used here is preferably polytetrafluoroethylene, which is the most excellent in heat resistance and non-adhesiveness, and is a material that is filled with glass fiber or carbon fiber to improve abrasion resistance. Is preferred. Then, the nest 6 is manufactured by, for example, cutting, and is adhered or screwed to the mold so that the predetermined air escape groove 2 can be formed.

In this way, since the inner surface of the air escape groove 2 is made of a fluorine-based resin, the resin that has flowed into the air escape groove 2 comes into close contact when the molded product is released after the resin sealing is completed. Will not be left behind.

[0034]

EFFECT OF THE INVENTION In a mold for transfer molding used for resin sealing of a semiconductor device or the like, if the resin flows into the air escape groove provided in the cavity, the resin adheres to the cavity and is difficult to remove. According to the invention, the inner surface of the air escape groove is subjected to a non-adhesive treatment so that the resin does not adhere to it.

Then, it is possible to prevent the molded product from becoming defective due to the residue of the resin adhered to the air escape groove, and to prevent the work efficiency from being lowered due to a hand gap for removing the residue. As a result, the present invention greatly contributes particularly to the efficiency improvement of the resin sealing process of the semiconductor device.

[Brief description of drawings]

FIG. 1 is a partially enlarged perspective view of an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a main part of another embodiment of the present invention.

FIG. 3 is an enlarged perspective view of a part of an example of a resin sealing mold device.

[Explanation of symbols]

1 Cavity 2 Air escape groove 3 Dividing surface 3a Recess 4 Abutting surface 5 Release film 6
Nesting 7 Resin 8 Molded product 9
Mold device 10 Lower mold 20 Upper mold 30
Lead frame

Claims (3)

[Claims] 1. A cavity (1) and an air escape groove (2) are provided, wherein the cavity (1) is for molding a resin-sealed molded product, and is a lower mold (10) that abuts each other. ) And the upper mold (20), and the air escape groove (2) is a recess carved in the dividing surface (3) intersecting at least one side wall of the cavity (1). (3a)
And an abutting surface (4) that abuts and faces each other, and a non-adhesive treatment is applied to the inner surface of the resin-sealing mold device. 2. The resin sealing mold according to claim 1, wherein the air escape groove (2) has a release film (5) made of a fluorine resin or a silicon resin adhered to an inner surface thereof. Mold equipment. 3. The air escape groove (2) is provided with the dividing surface (3).
The mold device for resin encapsulation according to claim 1, further comprising a nest (6) made of a fluororesin fitted to the abutting surface (4).