JP2002187175A - Method for taking out semiconductor resin sealed molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly release the resin sealed molded objects 11 and 13 of a semiconductor element 7 from the molding surface of a mold without using an ejector pin. SOLUTION: After the resin sealing molding of the semiconductor element 7, preparatory mold opening is performed in a state forming a gap 30 of several ten - several hundred μm between the molding surfaces (parting line) of molds. Thereafter, compressed air 21 is introduced into the gap between the molding surfaces under pressure and guided to the gaps between the resin molded objects 11 and 13 and the molding surfaces to release the resin molded objects 11 and 13 by the pressure of compressed air 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of sealing and molding a semiconductor element with a resin using a mold for molding and sealing a semiconductor resin. The present invention relates to an improvement in a method for removing a semiconductor-resin-encapsulated molded product, which allows a semiconductor-resin-encapsulated molded product to be easily removed from a mold by reliably releasing a resin-encapsulated molded product from a mold surface.

[0002]

2. Description of the Related Art A so-called transfer molding method is widely known as a method for molding a semiconductor element with a resin using a semiconductor resin molding apparatus equipped with a mold for semiconductor resin molding. . As a general configuration of this semiconductor resin sealing molding apparatus, for example, FIG.
As shown in (B), a fixed upper mold 1, a movable lower mold 2 opposed to below the fixed upper mold 1, a pot 3 disposed on the movable lower mold 2, The pot 3 and the cavity 5 disposed in the vicinity of the pot 3 are provided with a plunger 4 for pressing a resin material to be fitted into
When the upper and lower dies 1 and 2 are closed as shown in FIG. Resin encapsulation of a semiconductor element using such a molding apparatus is generally performed as follows. First, in a state in which the movable lower mold 2 is moved downward to open the upper and lower molds 1 and 2 (see FIG. 3B), the semiconductor is placed at a predetermined position on the mold surface of the upper and lower molds 1 and 2. A board on which the element 7 is mounted, a lead frame 8 and the like are supplied and set, and a resin material 9 is supplied into the pot 3. Next, the movable lower mold 2 is moved upward to clamp the upper and lower molds 1 and 2 (see FIG. 3A). At this time, the resin material 9 supplied into the pot 3 is heated and melted by the heaters 10 provided in the upper and lower molds 1 and 2. Next, when the resin material melted in the pot 3 is pressurized by the plunger 4, the molten resin material is injected into the cavity 5 from the position of the pot 3 through the transfer passage 6 and filled therein. Will be. Next, after a required curing time, the movable lower mold 2 is moved down again to open the upper and lower molds 1 and 2, and the resin molded body 11 in the transfer passage 6 and the cavity 5 is removed by the ejector pins 12 and the like. It protrudes out of the mold via the mold release mechanism and is released. next,
By removing unnecessary portions of the resin molded body 11 and unnecessary parts such as the lead frame 8, the resin in which the semiconductor element 7 is sealed in a resin molded body (mold package) 13 molded corresponding to the shape of the cavity 5. A sealed molded product can be obtained.

As another method of releasing the resin molded body, for example, a valve pin is provided at a cavity position (not shown), and compressed air is introduced into the cavity after resin molding. It is known that the resin molding is forcibly released from the mold.

[0004]

In this type of mold configuration, as described above, a release mechanism having an ejector pin 12 at the position of the cavity 5 or the transfer passage 6, or a compressed air is used. The release mechanism used is adopted,
Therefore, when the mold is opened, the resin molded body 11 can be forcibly protruded from the mold surface via these release mechanisms. In such a release mechanism, the function and effect that the resin molded body can be reliably projected can be obtained. However, the following problems have been pointed out. For example, when an ejector pin is used, a scar or a crack may be generated on the surface of the resin molded body due to a pin tip surface, and in this case, there is a problem in resin molding that the product is defective. Further, when the ejector pin is used, the mold structure becomes extremely complicated due to the small size of the semiconductor resin-encapsulated molded product, and the timing of projecting the resin molded body by the ejector pin is adjusted. And the cost of designing and manufacturing the mold is increased. Further, when using the release mechanism using the above-described compressed air, there is an advantage that the mold structure can be simplified, but in that the resin molded body is forcibly protruded from the mold surface, It is similar to the case of using an ejector pin, and no special countermeasures have been taken. Therefore, at present, when the resin molded product is released from the mold surface, a micro crack is formed on the surface of the resin molded product. However, it has not been possible to reliably solve the problems in resin molding, such as the occurrence of defects or partial loss of the product, resulting in defective products.

According to the present invention, there is provided a semiconductor resin encapsulation that does not cause microcracks or the like on the surface of a resin molded product when it is released from a mold surface, and that can simplify the device structure and reduce costs. An object of the present invention is to solve the above-mentioned conventional problems by providing a method for removing a molded article.

[0006]

According to the present invention, there is provided a method for removing a molded article of a semiconductor resin encapsulation, wherein a molten resin material is injected under pressure into a cavity opposed to a mold surface of a mold. After the semiconductor element fitted and set in the resin mold is molded with the resin, the resin molded body is released from the mold surface of the mold to remove the semiconductor resin mold from the mold. A removal method, wherein a preliminary mold opening step of performing a preliminary mold opening in a state in which a slight gap is formed between the mold surfaces after resin sealing molding of the semiconductor element, and the mold after the preliminary mold opening step A step of releasing a resin molded product of the semiconductor element from the mold surface of the mold by injecting gas between the surfaces. Further, the gap between the mold surfaces in the preliminary mold opening step is set to several tens μm to several hundred μm. Therefore, according to this method, a gas is press-fitted between the mold surfaces in the preliminary mold opening step in which a slight gap is formed between the mold surfaces, and the gas is guided between the resin molded body and the mold surface. Thereby, the resin molded body can be smoothly released from the mold surface by the pressure of the gas.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A feature of an embodiment of the present invention described below is a method for removing a semiconductor resin molded article employing a release mechanism using compressed air. A preliminary mold opening step of performing a preliminary mold opening in a state in which a slight gap is formed between mold surfaces, and after the preliminary mold opening step, gas is injected between the mold surfaces to form a resin-sealed molded body of the semiconductor element. From the mold surface of the mold. Further, the gap between the mold surfaces in the preliminary mold opening step is set to several tens μm to several hundred μm.

[0008]

FIG. 1 shows an example of a mold structure for carrying out a method for removing a semiconductor-resin-sealed molded product according to the present invention, and FIGS. 2A, 2B, 2C and 2C. D) is a process drawing for explaining the process, which will be described below with reference to the drawings.

FIG. 1 shows a main part of the mold structure.
An upper die 1 on a fixed side, a lower die 2 on a movable side opposed to the lower part of the fixed upper die, a pot 3 arranged on the lower die, and a plunger 4 for pressurizing a resin material to be fitted into the pot. And The pot 3 and the cavity 5 disposed near the pot communicate with each other via a passage 6 for transferring the molten resin material when the upper and lower dies 1 and 2 shown in FIG. It is provided as follows. Components substantially the same as those of the conventional mold described above are denoted by the same reference numerals as those described above, reference numeral 7 denotes a semiconductor element, reference numeral 8 denotes a lead frame, reference numeral 9 denotes a resin material, and reference numeral 9 denotes a resin material. Reference numeral 10 denotes a heater, reference numeral 11 denotes a resin molded body, reference numeral 13 denotes a resin molded body (mold package), and reference numeral 14 denotes a concave portion for supplying and setting the lead frame 8. The configuration different from the configuration of the conventional mold is as follows. That is, a mold release mechanism 20 using gas pressure is employed instead of a mold release mechanism using an ejector pin in the configuration of a conventional mold. The release mechanism 20 is connected to an introduction passage 22 for compressed air 21 connected to an air compressor (not shown) and through the introduction passage when the upper and lower dies 1 and 2 are closed (see FIG. 1A). A sealing member 23 for preventing the supplied compressed air 21 from flowing out of the mold surface (PL surface) to the outside; and a sealing member 23 provided between the air compressor and the compressed air introduction passage 22 to be provided. And a control valve (not shown) for opening and closing the valve.

Hereinafter, the resin sealing molding operation of a semiconductor element using the mold will be described. First, the movable lower mold 2 is moved down to open the upper and lower molds 1 and 2 [FIG.
(B)], at a predetermined position (a concave portion 14 formed on the mold surface of the lower mold 2 in the illustrated example) on both upper and lower mold surfaces.
A substrate on which the semiconductor element 7 is mounted, a lead frame 8, and the like are supplied and set via an appropriate transport mechanism (not shown), and a resin material 9 is supplied into the pot 3. Next, the movable lower mold 2 is moved upward to clamp the upper and lower molds 1 and 2. At this time, the resin material 9 supplied into the pot 3 is heated and melted by the heaters 10 provided in the upper and lower molds. Next, when the resin material melted in the pot 3 is pressurized by the plunger 4, the molten resin material is injected into the cavity 5 from the position of the pot 3 through the transfer passage 6 and filled therein. Will be. Next, after a required cure time, as described later, the release mechanism 2
0, the resin molded bodies 11 and 13 in the transfer passage 6 and the cavity 5 are released from the mold surface, and the movable lower mold 2 is moved down again to open the upper and lower molds 1 and 2. . Next, the upper and lower molds 1 and 2 are opened, and the resin molded bodies 11 and 13 in the released state are carried out to the outside via an appropriate take-out mechanism (not shown). Next, by removing unnecessary portions of the resin molded bodies 11 and 13 and unnecessary parts such as the lead frame 8, the semiconductor element 7 is placed in a resin molded body (mold package) 13 molded corresponding to the shape of the cavity 5. Can be obtained.

Hereinafter, the release operation of the resin molded bodies 11 and 13 by the release mechanism 20 will be described in more detail. FIG.
(A), the resin material melted in the pot portion is pressurized by the plunger 4 and the molten resin material 19 is transferred to the transfer passage 6.
The step of resin-molding the semiconductor element 7 on the lead frame 8 fitted and set in the cavity by injecting and filling the cavity 5 under pressure is shown. At the time of the resin encapsulation molding step, a required mold clamping pressure is applied to the lead frame 8 by the upper and lower molds 1 and 2. Is supported in a pinched state. Further, a required resin pressing force by the plunger 4 is applied to the molten resin material 19. FIG. 2B shows a cure time step after the resin sealing molding step.
The resin moldings 11 and 13 are hardened in the transfer passage 6 and the cavity 5 by the curing time step. FIG.
(C) shows a preliminary mold opening step of forming a preliminary mold opening state for forming a slight gap 30 between the mold surfaces (PL surfaces) of the upper and lower molds 1 and 2. In the preliminary mold opening step, to form the gap 30, for example, a mold surface (PL
It is sufficient to open the mold so that the lower mold 2 is moved down to a position where the distance between the two surfaces is several tens μm to several hundred μm.
At least, by releasing the mold clamping pressure by the upper and lower molds 1 and 2, the crimped state between the mold surface and the lead frame 8 and the molded resin molded bodies 11 and 13 is set to a state where the crimped state is released. I just need. Further, as described below, when the gap 30 is formed, the space between the mold surfaces (PL surfaces) of the upper and lower molds 1 and 2 and the outside air are shut off via the seal member 23. Preferably, it is set. Further, the degree of the gap 30 can be appropriately adjusted in width according to a change in a resin material to be used or molding conditions. In FIG. 2D, after the preliminary mold opening step, a gas (in the illustrated example, compressed air 21) is press-fitted between the mold surfaces (PL surfaces) to remove the resin molded bodies 11 and 13 from the mold. 4 shows a resin molding release step of releasing the mold from the inner surface of the cavity 5 and the transfer passage 6 on the surface. In the resin molding release step, as described above, the clamping pressure by the upper and lower molds 1 and 2 is released, and a slight gap is formed between the mold surfaces (PL surfaces) of the upper and lower molds. 30 are configured. Therefore, in this state, when the control valve on the compressed air introduction passage 22 connected to the air compressor side is opened and the compressed air 21 is supplied between the mold surfaces through the introduction passage, the compressed air 21 is As a result, as shown by an arrow in FIG. 3D, the resin is forcibly pressed into the cavity 5 and the transfer passage 6 of the mold surface. Then, the compressed air 21 press-fitted into the resin molding part side is used for the mold surface, the lead frame 8 and the resin molded body 11.
As a result, the lead frame 8 and the resin moldings 11 and 13 are smoothly separated from the mold surface to be released. For this reason, the resin molding 1
When the molds 1 and 13 are released from the mold, no microcracks or the like are generated on the surface thereof, and a part thereof is not lost. Further, the overall structure of the mold apparatus can be simplified.

In the above-mentioned resin molded product releasing step,
Room temperature or cooled air may be pressed between the mold surfaces. In this case, a synergistic mold release effect by cooling the surfaces of the lead frame and the resin molded body can be expected in addition to the mold release function of the lead frame and the resin molded body by the gas injection described above. Further, another appropriate gas capable of obtaining the same effect as the above-described compressed air or cooling air may be press-fitted between the mold surfaces.

[0013]

According to the method of the present invention, the resin molded body can be smoothly released from the mold surface, so that microcracks and the like do not occur on the surface of the resin molded body at the time of mold release. In addition, it is possible to prevent adverse effects such as the occurrence of defective molding due to partial loss. In addition, since the resin molded body can be smoothly released from the mold surface, a part of the resin molded body is lost at the time of mold release and remains on and adheres to the mold surface. Such adverse effects can be eliminated beforehand. Furthermore,
The overall structure of a mold apparatus for performing the method of the present invention is
The present invention has excellent practical effects such as simplification as compared with the conventional mold structure and cost reduction.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a main part of a mold in a semiconductor resin encapsulation molding apparatus for carrying out a method of the present invention.
FIG. 1A shows a mold clamping state of the mold, and FIG. 1B shows a mold open state of the mold.

2 (A), 2 (B), 2 (C), 2 (D) are process diagrams for explaining each process of the method of the present invention.

FIG. 3 is a partially cut-away longitudinal front view showing a main part of a general mold structure in a semiconductor resin encapsulation molding apparatus. FIG. 3 (A) shows a mold clamping state of the mold, and FIG. Indicates a mold open state of the mold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper mold 2 Lower mold 3 Pot 4 Plunger 5 Cavity 6 Transfer passage 7 Semiconductor element 8 Lead frame 9 Resin material 10 Heater 11 Resin molding 13 Resin molding (mold package) 14 Concave 19 Molten resin material 20 Release mechanism 21 Compressed air 22 Introducing passage 23 Seal member 30 Gap

Claims (2)

[Claims] 1. A molten resin material is injected under pressure into a cavity facing a mold surface of a mold, and a semiconductor element fitted and set in the cavity is subjected to resin sealing molding. By releasing the resin molded body from the mold surface, a method for removing a semiconductor resin molded article from the mold, the semiconductor resin molded article, after the resin sealing molding of the semiconductor element, A preliminary mold opening step of performing a preliminary mold opening in a state where a slight gap is formed between the mold surfaces; and after the preliminary mold opening step, gas is injected between the mold surfaces to seal the semiconductor element with a resin. A resin molding release step of releasing the molding from the mold surface of the mold. 2. The method according to claim 1, wherein a gap between the mold surfaces in the preliminary mold opening step is set to several tens μm to several hundred μm.