JPH09148350A - Method of resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of resin molding, which produces an extremely smooth surface by coating a jig with fluororesin having a smooth surface, putting it in a container holding liquid epoxy and thermally hardening the epoxy whose surface is in contact with the fluororesin on the jig. SOLUTION: A jig 3 coated with fluororesin 4 having a smooth surface is put in a container 1 holding liquid epoxy 2. The epoxy 2, whose surface is in contact with the fluororesin 4 on the jig 3, is hardened by heat, and the jig is extracted from the container. For example, the fluororesin 4 is sufficiently smoothed by polishing after attached to the work surface of the jig 3. Preferably, the fluororesin 4 is a viscous coating material that has weak adhesion to epoxy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding method used for sealing a semiconductor element with resin, and more particularly to a resin molding method for forming a smooth surface on the surface of a molding resin.

[0002]

2. Description of the Related Art Conventionally, transfer molding method (casting method) and transfer molding method (casting method) are generally known as resin molding methods used for resin sealing of semiconductor elements. Has been.

The transfer molding method is a method in which a powdery or granular molding material is preliminarily preliminarily formed and then put into a molding die, whereas the casting method is a method in which a liquid resin is placed in a resin container. Although it is a method of pouring and molding, a casting method is usually used for a variety of small-quantity production.

FIG. 4 is a process sectional view showing a conventional resin molding method by a casting method.

First, as shown in FIG.
Liquid epoxy resin 102 is poured into 1 to form a smooth jig 1 for obtaining a smooth surface on epoxy resin 102 to be molded.
A release agent 104 made of an oily substance is applied to the pressing portion of 03 with a brush or a spray in order to make it easy to remove it. When the light emitting element, the light receiving element, and the like are resin-sealed, the elements are fixed in the container 101 before this step.

Next, the smoothing jig 103 is lowered from above, pressed against the epoxy resin 102, and cured by heating (FIG. 4B), and then the smoothing jig 103 is removed (see FIG. 4).
(C)). As a result, a smooth surface 102B is obtained on the surface of the molding resin 102A.

[0007]

However, in the above-mentioned conventional resin molding method, the releasing agent applied to the smoothing jig 103 is a kind of oil, so the smoothing jig 103 is pressed against the epoxy resin 102. At this time, an oil film is formed on the resin surface of the pressed portion. Since the oil film is not evenly distributed, it is not smooth, and thus the obtained molding resin 1
The smoothness of the smooth surface 102B of 02A was not sufficiently satisfactory.

Molding resin 10 having poor smoothness as described above
In 2A, for example, when the light emitting element or the light receiving element is resin-sealed, the wavefront of light to be output or input is distorted, and the element function cannot be sufficiently achieved.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a resin molding method capable of forming a highly accurate smooth surface. Another object is to provide a resin molding method capable of forming a thick smooth surface with a small amount of resin. Still another object is to provide a resin molding method capable of easily forming a highly accurate smooth surface.

[0010]

In order to achieve the above object, a feature of the first invention is that a jig is attached with a fluororesin,
The surface of the fluororesin is made smooth beforehand, and after potting a liquid epoxy resin into the container, the epoxy resin is heated by pressing the fluororesin surface of the jig against the liquid surface of the epoxy resin to heat the epoxy resin. Hardening and removing the jig from the hardened epoxy resin.

According to the first aspect of the present invention, attention is paid to the fact that the fluororesin is a coating agent made of a material having a low adhesive force to the epoxy resin and a high viscosity. By substituting the agent and smoothing the surface of the fluororesin in advance, a highly accurate smooth surface is formed.

A feature of the second invention is that, in the first invention, when the liquid level of the epoxy resin rises along the inner wall of the container after potting the epoxy resin, the liquid near the inner wall of the container is close to the inner wall of the container. It is to press the fluororesin surface of the jig against the liquid surface of the epoxy resin to the extent that it touches.

According to the second aspect of the invention, the epoxy resin is sucked up near the wall surface of the container due to the capillary phenomenon, and the capillary phenomenon forms a smooth surface at a higher position than the normal liquid level.

A third aspect of the present invention is the first or second aspect of the invention.
In the invention, the jig is made of a fluororesin.

According to the third invention, in the first or second invention, the step of attaching the fluorine resin to the jig is unnecessary.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional process drawing showing a resin molding method according to the first embodiment of the present invention.

In the resin molding method of the present embodiment, first, as shown in FIG. 3A, the fluorine resin 4 is attached to the pressing portion of the metal smoothing jig 3 for forming a smooth surface, The surface of the fluororesin 4 is polished to be sufficiently smooth.
As the fluorine resin 4, a coating agent (for example, Teflon) made of a material having a low adhesive force to the epoxy resin 2 and a high viscosity is used. Then, the liquid epoxy resin 2 is potted into the container 1 using a syringe, a dispenser or the like.

Then, as shown in FIG. 1B, the smoothing jig 3 is lowered and pressed against the smooth surface forming portion of the epoxy resin 2 in the container 1, and in this state, the entire container 1 is heated and cured. Put in a bath and heat (for example, 125 ° C to 150 ° C),
The epoxy resin 2 is cured.

After that, as shown in FIG. 1 (c), the smoothing jig 3 is lifted and removed from the cured epoxy resin 2, and die cutting is performed. At this time, since the fluorine resin 4 having a low adhesive force to the epoxy resin 2 is used, the die can be easily removed. As a result, the molding resin 2A
A smooth surface 2B having excellent smoothness is formed on the surface.

FIG. 2 is a cross-sectional process diagram showing a resin molding method according to the second embodiment of the present invention. Elements common to FIG. 1 are designated by the same reference numerals, and the description of the same contents is omitted.

In the resin molding method of this embodiment, first, as shown in FIG. 3A, the fluororesin 4 is attached to the pressing portion of the metal smoothing jig 3A, and the surface of the fluororesin 4 is polished. And make it smooth enough. Here, when the smoothing jig 3A is pressed against the epoxy resin 2 later, the container 1
The pressing portion of the smoothing jig 3A according to the present embodiment is provided at a position displaced from the center toward the side wall so that the pressing is performed at a position close to the wall surface. And container 1
The epoxy resin 2 is potted inside. It is assumed that the liquid surface of the epoxy resin 2 at the time of completion of the potting is in a state of rising along the inner wall of the container 1 near the side wall of the container 1.

Then, as shown in FIG. 2B, the smoothing jig 3A is lowered. Then, when a part of the smoothing jig 3A is pressed so as to come in contact with a part of the epoxy resin 2, due to a capillary phenomenon, as shown in FIG.
The epoxy resin 2 is sucked up near the side wall of the. The epoxy resin 2 is cured by heating in this state. After that,
As shown in FIG. 2 (d), the smoothing jig 3A is lifted to remove from the cured epoxy resin 2 and die-cutting is performed.

As a result, on the surface of the molding resin 2D,
A smooth surface 2E having excellent smoothness is formed at a position higher than usual.

This embodiment has an advantage that a highly accurate smooth surface having a large thickness can be formed with a small amount of resin.

In the first and second embodiments, the smoothing jig 3 or 3A is made of metal, the fluororesin 4 is attached to the metal smoothing jig, and the surface of the fluororesin 4 is smoothed by polishing. However, the smoothing jig itself may be made of the fluororesin 4 and the surface thereof may be smoothed by polishing or the like.

Next, an example in which the resin molding method shown in the first or second embodiment is applied to resin sealing of a semiconductor element will be described.

FIG. 3 is a cross-sectional view of an essential part showing a resin sealing process of a light emitting element to which the resin molding method of the present invention is applied.

First, for example, a plurality of containers 1 arranged in a column are prepared, and the light emitting elements 11 are fixed in each container 1 as shown in FIG. 3 (a). At this time, the light emitting element 11
It also protects the Then, a liquid epoxy resin 2 to which a curing agent, a filler and the like have been added in advance is poured into the container 1.

After that, the process proceeds to the process shown in FIGS. 1A to 1C or 2A to 2D to complete the resin sealing of the light emitting element 11.

As described above, when the resin molding method described in the first or second embodiment is applied to the resin sealing of the light emitting element 11, the smoothness of the smooth surface of the resin is excellent,
It is possible to take out light without distorting the wavefront.
In particular, when the resin molding method of the second embodiment capable of forming a thick smooth surface is applied, the bonding wire of the light emitting element 11 can be sufficiently sealed with a small amount of resin, which is advantageous.

[0031]

As described above in detail, according to the first aspect of the invention, the jig is coated with the fluororesin, the surface of the fluororesin is preliminarily smoothed, and the liquid epoxy resin is potted in the container. After that, the epoxy resin is heated while the fluororesin surface of the jig is pressed against the liquid surface of the epoxy resin to cure the epoxy resin, and the jig is removed from the cured epoxy resin. It is possible to form a smooth surface of.

According to a second invention, in the first invention, when the liquid level of the epoxy resin rises along the inner wall of the container after potting of the epoxy resin, the epoxy resin near the inner wall of the container Since the fluororesin surface of the jig is pressed against the epoxy resin liquid surface to such an extent that it can be touched, a smooth surface having a large thickness can be formed with a small amount of resin, in addition to the same effect as the first invention. There is an effect.

According to the third invention, the first or second
In the invention, since the jig is made of fluororesin,
The step of attaching the fluororesin to the jig becomes unnecessary, and it becomes possible to easily form a highly accurate smooth surface.

[Brief description of the drawings]

FIG. 1 is a sectional process drawing showing a resin molding method according to a first embodiment of the present invention.

FIG. 2 is a sectional process diagram showing a resin molding method according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of an essential part showing a resin sealing process of a light emitting element to which the resin molding method of the present invention is applied.

FIG. 4 is a process sectional view showing a conventional resin molding method by a casting method.

[Explanation of symbols]

 1 container 2 epoxy resin 2A, 2D molding resin 2B, 2E smooth surface 3, 3A smoothing jig 4 fluororesin 11 light emitting element

Claims (3)

[Claims] 1. A fluororesin is adhered to a jig, the surface of the fluororesin is smoothed in advance, a liquid epoxy resin is potted into a container, and then the fluororesin of the jig is placed on the liquid surface of the epoxy resin. A resin molding method comprising: heating the epoxy resin while pressing the resin surface to cure the epoxy resin; and removing the jig from the cured epoxy resin. 2. When the liquid level of the epoxy resin rises along the inner wall of the container after potting of the epoxy resin, the epoxy resin liquid level near the inner wall of the container is fixed to the fluorine resin of the jig. The resin molding method according to claim 1, wherein the resin molding method comprises pressing the surface to the extent that it touches the surface. 3. The resin molding method according to claim 1 or 2, wherein the jig is made of a fluororesin.