KR100884733B1 - Coating method of epoxy release wax on chip package mold and thereby suitable coating seat - Google Patents

Abstract

The present invention relates to a method for applying epoxy release wax to a chip packaging mold and a coating sheet suitable for the same, and more particularly, to prevent the epoxy from sticking to the packaging mold when the semiconductor chip is packaged with epoxy. A method for applying an epoxy release wax to a chip packaging mold capable of effectively applying the release wax and a coating sheet suitable therefor.

The object of the present invention is to shorten the work time for applying wax to the cavity of the upper and lower molds in the encapsulation operation of chip packaging, thereby improving the work efficiency and to facilitate the worker's manual removal of the wax coating agent. A method for applying an epoxy release wax to a removed chip packaging mold and a coating sheet suitable therefor.

In order to realize the above object, the coated sheet according to the present invention is manufactured to a size that can cover the contact surfaces of the upper and lower molds 55 and 53 for chip packaging at the same time, and heat resistance that does not burn by the temperature of the mold. It is characterized by consisting of a support (1) made of a fiber material having a and a wax (2) which is an epoxy releasing agent uniformly applied to the support (1).

In addition, the method according to the present invention is manufactured to a size that can cover the contact surfaces of the upper and lower molds 55 and 53 for chip packaging at the same time, and the support portion 1 uniformly coated with wax 2 which is an epoxy release agent. And seating to cover the entire upper surface of the lower mold (53),

Pressing the support part 1 by lowering the upper mold 55 when the support part 2 is seated on the lower mold 53;

When the support part 1 is pressed, the support part 1 located in the cavity 51 is filled in the cavity 51 to apply the wax 2.

Chip Packaging, Semiconductor Packaging Coating Sheet, Epoxy Molding

Description

COATING METHOD OF EPOXY RELEASE WAX ON CHIP PACKAGE MOLD AND THEREBY SUITABLE COATING SEAT}

The present invention relates to a method for applying epoxy release wax to a chip packaging mold and a coating sheet suitable for the same, and more particularly, to prevent the epoxy from sticking to the packaging mold when the semiconductor chip is packaged with epoxy. A method for applying an epoxy release wax to a chip packaging mold capable of effectively applying the release wax and a coating sheet suitable therefor.

In general, in order to manufacture and use a semiconductor chip, not only a very small size, but also a packaging process in which a lead wire is connected to a chip and then wrapped in epoxy to protect a weak chip.

In the packaging process, chips and lead wires are placed in a mold, and then liquid epoxy is supplied to a plurality of cavities (spaces forming one chip package), and pressurized and encapsulated at a high temperature (about 175 ° C). Will be done.

As an example of the chip manufactured in the above packaging process, as shown in FIG. 4, the lead line L and the chip C are connected by a wire W, and the lead wire L and the wire W are And the chip (C) is protected while being sealed by the epoxy (E), the thickness d of the packaging state is about 3mm or so.

The mold applied to the chip packaging process as described above is not only seated on the base 50 as shown in FIGS. 5 and 6, but also a plurality of cavities 51 are sequentially formed, and each cavity 51 is formed. The lower mold 53 in which the injection path 52 of a complicated shape is formed so that epoxy (E) may be injected into the cavity, and the cavity opposite to the cavity 51 of the lower mold 53 is formed, and the lifting plate 54 is formed. Consists of the upper mold 55 is installed on.

In the above packaging process, the upper and lower molds 55 and 53 are closed and epoxy (E) is injected while the cavity 51 of the upper and lower molds forms a space, and the epoxy (E) is solidified by maintaining it for a predetermined time. At this time, since the temperature of the mold is heated to about 175 ° C, foreign substances such as oxides, dusts, etc., in which the epoxy (E) is oxidized during the solidification of the epoxy (E), are introduced into the cavity 51 of the mold. Sticks.

Therefore, in order to remove the oxides, foreign substances, and the like, a cleaning operation and a wax coating operation are performed after a certain number of encapsulation operations.

In the cleaning operation, a cleaning agent prepared by mixing a predetermined chemical for separating a mold such as epoxy oxide and melamine or rubber is placed between upper and lower molds 55 and 53, and then the upper mold 55 is lowered to lower the lower mold. (53) and keep it for about 5 minutes to keep the foreign substances on the cleaning agent.

In addition, after the above-mentioned cleaning operation, wax is applied to prevent the epoxy oxide, foreign substances, etc. from adhering to the cavity 51 of the mold during encapsulation during chip packaging, and the wax is an epoxy releasing agent, such as melamine and rubber. The wax coating agent 56 mixed with the solid and the like is pressed in the upper and lower molds 55 and 53 so that the wax is buried in the cavity 51.

That is, as shown in FIG. 5, after the wax coating agent 56 is positioned on the upper portion of the cavity 51 of the lower mold 53, the upper mold 55 is lowered to pressurize it, and at the same time, the wax coating agent is melted. Maintaining about 5 minutes to ensure that the wax is sufficiently applied inside the cavity (51).

However, as described above, in order to apply wax to the cavity of the mold, the wax coating agent is placed on the cavity of the mold, and then the upper mold is lowered and pressurized, and if the pressure is maintained for 5 minutes or more, the mold is high temperature (about 175 ° C). There is a problem that the operation time is not only dangerous to put the wax coating agent on each of the cavity is formed in multiple lines in close proximity to the worker because the work time is about 10 minutes.

In other words, the preparation time required to place the wax coating agent on the mold and heat the mold to a high temperature takes about 5 minutes, and it takes about 5 minutes to pressurize the wax coating agent between the upper and lower molds.

In addition, when the melamine or rubber wax coating agent is pressed into the upper and lower molds of high temperature, they stick to the cavity of the mold and do not fall well, resulting in chemical smoke as the product burns. It is difficult to remove the wax coating agent, resulting in a burn or the like.

Accordingly, an object of the present invention is to solve the above problems, and in the encapsulation operation of the chip packaging operation, the work time for applying wax to the cavity of the upper and lower molds is reduced to about 10 seconds to improve the work efficiency and the operator The present invention provides a method for applying an epoxy release wax to a chip packaging mold which eliminates the risk of easy removal of the wax coating agent and a coating sheet suitable therefor.

In order to realize the above object, the coated sheet according to the present invention is manufactured to a size that can cover the contact surface of the upper and lower molds for chip packaging at once or formed to a size that covers the upper surface of each cavity group and the mold It is characterized by comprising a support made of a fiber material having a heat resistance that does not burn by the temperature of and a wax which is an epoxy releasing agent uniformly applied to the support.

In addition, the method according to the present invention is manufactured to a size large enough to cover the contact surface of the upper and lower molds for chip packaging at the same time, and seating the support portion coated with wax, which is an epoxy releasing agent, to cover the entire upper surface of the lower mold. Steps,

Pressing the support by lowering the upper mold when the support is seated on the lower mold;

When the support is pressed, the support located in the cavity is filled in the cavity, characterized in that configured to apply a wax.

As described above, the present invention forms a supporting part with a nonwoven fabric, carbon fiber, plastic, and the like, and applies wax, which is an epoxy releasing agent, so that the wax can be applied to the entire upper and lower molds by one operation when wax is applied to the cavity. This has the advantage of improving work efficiency and eliminating the risk of burns to workers.

1 and 2 are cross-sectional views showing a perspective view showing an application sheet for applying epoxy release wax to a chip packaging mold according to the present invention, and a state positioned between upper and lower molds, wherein the upper and lower molds 55 and 53 are in contact with each other. The support part 1 and the support part made of a fiber material which is formed to a size enough to cover the surface or cover the upper surface of each cavity group and is made of a fiber material which is excellent in heat resistance and does not stick to the mold. It consists of the wax (2) which is an epoxy mold release agent apply | coated uniformly to (1).

That is, the size of the support is formed to the size to cover the entire cavity formed in the upper and lower molds at a time or to cover the cavity group formed by dividing into a plurality of groups, which is to adjust the size of the support for convenience in the process Produce it.

Since the support part 1 must be able to withstand at about 175 degreeC which is the working temperature of a metal mold | die, it is good to select the support part 1 which has heat resistance about 200 degreeC.

The support part 1 may be made of natural fiber (paper, cotton, etc.), chemical fiber (nonwoven fabric, glass fiber, carbon fiber, nylon, etc.), plastic, etc., and the plastic is made of heat-resistant plastic on a sheet. Is used.

In particular, the thickness D of the support 1 is formed slightly thicker (approximately 3.5 mm) than the average thickness d (approximately 3 mm) of the packaged chip, thereby closing the cavity 51 when the upper and lower molds 55 and 53 are closed. It is set to such an extent that it can be filled into the wax 2 and apply | coated inside.

The wax 2 applied to the support 1 is formed in a liquid, solid (powder) or the like, in the case of a liquid, the wax 2 is formed by being buried in the wax 2. It is mixed with a separate bonding material (not shown) and applied to the support 1.

In particular, when the wax 2 is applied to the support 1, the wax 2 is applied very uniformly so that the wax 2 is uniformly applied to the cavity 51 while the upper and lower molds 55 and 53 are in contact with each other. .

When applying the wax (2) to the support (1), in the case of a liquid is applied to an amount that does not flow in the support (1), in the case of powder, the support (1) after the bonding of the wax (2) When the amount does not flow down, the above-described amount is applied by applying a predetermined amount to prevent the wax (2) from boiling in the mold at high temperature does not overflow to the outside and is too insufficient to be applied to the inside of the mold.

Referring to the operation and effect of the present invention as described above, if the chip packaging operation is repeated a certain number of times, the oxide stuck to the cavity 51 of the mold due to the properties of the epoxy (E), as well as the foreign matter is burned.

If an oxide or the like is generated in the cavity 51 of the mold, the cleaning agent is to be cleaned by placing a cleaning agent between the upper and lower molds 55 and 53 and pressing the cleaning agent. In the state in which 55 is raised, the operator places the support part 1 coated with wax 2 on the upper surface of the lower mold 53.

For example, when using a support manufactured to a size that can cover the entire upper and lower mold, when the support 1 is seated on the upper surface of the lower mold 53 as shown in FIG. It is lowered and brought into close contact with the lower mold 53. In this state, since the support 1 is squeezed between the upper and lower molds 55 and 53 as shown in Fig. 3, the thickness of the supporting part 1 is remarkably increased. Although reduced, the support 1 located in the cavity 51 is only slightly pressurized (by the difference between the thickness D of the support and the thickness d of the package (and consequently the width of the cavity)), thereby filling the interior of the cavity 51 to the edge. do.

When the support 1 is filled in the cavity 51, the wax 2 applied to the support 1 is applied to the inner surface of the cavity 51, and the upper mold 55 is lowered and the wax is lowered. About 10 seconds are enough to apply and release again, The wax 2 is apply | coated inside the cavity 51 enough.

That is, since the thickness D of the support part 1 is thicker than the height of the space of the cavity 51 formed when the upper and lower molds 55 and 53 are closed, for example, a nonwoven fabric or the like is used where the cavity 51 is not formed. While the support part 1 is made of a lot of compression, while the part of the cavity 51 is slightly compressed, the inside of the cavity 51 is filled tightly, which causes wax 2 to be applied to the corner of the inside of the cavity 51. It will be possible.

In particular, since the support 1 is in close contact with the entire upper and lower molds 55 and 53, the wax 2 is applied to the injection path 52 for injecting the epoxy E in one operation, thereby providing epoxy to this portion. And it is possible to prevent the adhesion of foreign matter.

That is, when using a wax coating agent 56 made of conventional rubber or melamine, it is not easy to apply wax to the injection path 52, because one wax coating agent must be placed on each of the cavities 51. It is possible to apply the wax (2) to the cavity 51 and the injection path 52 in the operation of.

Of course, the same effect can be obtained even if wax is applied to the cavity of the mold by using a plurality of support parts each having a size formed to cover each cavity group of the upper and lower molds.

1 is a perspective view showing a state in which wax is applied to fibers as an application sheet for applying epoxy release wax to a chip packaging mold according to the present invention;

Figure 2 is a schematic cross-sectional view showing a state where the wax-coated fiber according to Figure 1 is located between the upper and lower molds;

3 is a partially enlarged cross-sectional view showing a state when the upper and lower molds are engaged in FIG.

4 is a cross-sectional view showing an example of a chip generally packaged with epoxy;

5 is a schematic diagram showing a mold used in the chip packaging process of FIG.

FIG. 6 is a perspective view showing an example of a lower mold in FIG. 5; FIG.

* Explanation of symbols for the main parts of the drawings

1: support portion 2: wax

51: cavity 52: with injection

53: lower mold 55: upper mold

Claims (8)

Manufactured to be large enough to cover the contact surfaces of the upper and lower molds for chip packaging at once, or to the size to cover the upper surface of each cavity group, and made of a fiber material with heat resistance that does not burn by the temperature of the mold. And wax, which is an epoxy releasing agent that is uniformly applied to the above-described support part, The thickness of the support is thicker than the height of the cavity, which is the average thickness of the chip being packaged, so that when the upper and lower molds are closed, the support is filled into the cavity to apply wax to the chip packaging mold, characterized in that Application sheet for applying epoxy release wax. It is manufactured to a size that can cover the contact surfaces of the upper and lower molds for chip packaging at once, or is formed to a size that covers the upper surface of each cavity group, and has a heat resistance that does not burn due to the temperature of the mold. And a wax, which is an epoxy releasing agent, which is uniformly coated on the support, The thickness of the support is thicker than the height of the cavity, which is the average thickness of the chip being packaged, so that when the upper and lower molds are closed, the support is filled into the cavity to apply wax to the chip packaging mold, characterized in that Application sheet for applying epoxy release wax. The method of claim 1, The support sheet for applying the epoxy release wax to the chip packaging mold, characterized in that the support is composed of natural fibers. The method of claim 1, An application sheet for applying the epoxy release wax to the chip packaging mold, characterized in that the support portion is composed of chemical fibers. delete The method according to any one of claims 1 to 4, An application sheet for applying epoxy release wax to the chip packaging mold, characterized in that the wax applied to the support is in a liquid state. The method according to any one of claims 1 to 4, The wax applied to the support portion is a coating sheet for applying epoxy release wax to the chip packaging mold, characterized in that the solid powder state that can be attached to the support portion. The average thickness of the chip that is packaged to be large enough to cover the contact surfaces of the upper and lower molds for chip packaging or to cover the upper surface of each cavity group, and the wax, which is an epoxy release agent, is uniformly coated Seating the support formed in the lower mold thicker than the height of the in-cavity, Pressing the support by lowering the upper mold when the support is seated on the lower mold; And when the support is pressurized, the support located in the cavity is filled into the cavity to apply the wax, thereby applying epoxy release wax to the chip packaging mold.

Images