JPS61217216A - Forming of tablet - Google Patents

Abstract

PURPOSE:To provide the manufacturing method of tablet, low in content of air and high in density, by forming powdered resin through a plurality of pressing processes. CONSTITUTION:The desired amount of powdered resin 2 is supplied into the receiving hole 4 of a die 3 to fill it. A pair of punches 5, whose respective tip ends are faced to the receiving hole 4 of the die 3, are advanced mutually to effect primary press and form the powdered resin 2, being supplied between the punches 5, by compression and whereby the tablet 1, having bulk density of about 90%, is obtained. This tablet 1 is taken out of the receiving hole 4 and is thrown into the receiving hole 7 of another forming machine. The receiv ing hole 7 is provided with a rectangular section and the lengthwise length of the rectangle is the length of the diameter of the tablet 1 substantially while the widthwise length of the same is the thickness of the tablet 1 substantially. The tablet 1, thrown into the receiving hole 7, is pressed again by the secondary press effected by the mutual advance movements of a pair of punches 8, whose tip ends are faced to the receiving hole 7, therefore, the very high bulk density of about 99% of the tablet 1 may be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing tablets, which are solid materials used in transfer resin molds.

[Background technology]

2. Description of the Related Art In the manufacture of semiconductor devices, transfer molding using resin is often used as a technique for sealing the main parts of chips and the like. In this transfer resin mold method, for example, "Electronic Materials J, March 1973 issue, published by Kogyo Kenkyukai, March 1, 1973, P4
As described in pages 8 to 54, tablets obtained by press-molding and solidifying resin are used as the sealing material.

By the way, in tablet molding as described in the above-mentioned document, powdered resin accommodated in a die is molded by a pair of punches.

However, since tablets are formed by unidirectional pressure molding, the bulk density during tablet molding is as low as 90% of the density of the resin after curing, and approximately 10% of air exists inside. This air remains (traps) as voids (bubbles) inside the package during molding, reducing the moisture resistance of the product, or, due to the high air content, the mechanical strength of the tablet itself decreases, causing cracks and chips. It has been found by the inventor that the bulk density is easy.The bulk density is given by the following equation.

[Object of the Invention] An object of the present invention is to provide a method for producing a high-density tablet with a low air content.

Another object of the present invention is to provide a tablet that makes it possible to manufacture semiconductor devices with high moisture resistance.

Another object of the present invention is to provide a tablet that has high mechanical strength and does not crack or chip.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, in the method for manufacturing a tablet of the present invention,
After the powder resin is firstly pressurized from one direction, it is secondly pressurized from a direction perpendicular to the first pressurization direction, so the powder resin is pressurized as a whole and has a low air content. It becomes a dense tablet.

Therefore, the mechanical strength of the tablet itself is high,
It becomes less likely to crack or chip when handled, and
Since the air content is low, semiconductor devices manufactured using this tablet will have almost no voids in the package, resulting in better moisture content and higher reliability.

〔Example〕

FIG. 1 is a flowchart showing a method for manufacturing a tablet according to an embodiment of the present invention, FIG.
The figure is a cross-sectional view showing the second pressurized state of the powdered resin during tablet production, and FIG. 4 is a perspective view showing the tablet.

In this embodiment, the disk-shaped tablet 1 as shown in FIG. Manufactured through. Powdered resin 2 that is the material for tablet 1
A lot of things such as a base resin, a hardening agent, a curing accelerator, a filler 2, a coloring agent, a coupling agent, a flame retardant additive, a plasticizer, a diluent, a mold release agent, etc. are kneaded to form a tablet 1. When used in transfer molding equipment, it meets various requirements. That is, the base resin undergoes a crosslinking reaction and is cured by the action of a curing agent. Further, the curing accelerator has the effect of accelerating the curing reaction. The filler has the effect of adjusting viscosity, coefficient of thermal expansion, and mechanical strength.

The colorant colors the entire powdered resin and determines the color of the pancage formed by the resin mold. The coupling agent has the effect of improving wetting and adhesion between the resin and the inorganic substance. The flame retardant additive has the effect of making the resin flame retardant.

The plasticizer acts on the internal distortion, relaxation, and crack resistance of the resin. The diluent has the effect of determining the flow rate of melted resin during resin molding. The mold release agent has the effect of making it easier for the cured resin to be released from the mold after resin molding.

In tablet molding, a desired amount of the powdered resin 2 as described above is supplied and filled into the receiving hole 4 of the die 3 as shown in FIG. Thereafter, a pair of bunches 5 whose tips face the accommodation hole 4 of the die 3 are mutually advanced to perform primary pressure, and the powdered resin 2 supplied into the bunches 5 is
is compression molded. In conventional tablet molding, this completes the work, but in this embodiment, a second pressure treatment is performed. The powdered resin 2 is turned into a tablet 1 having a bulk density of about 90% by the first pressure treatment. This tablet 1 is taken out from the accommodation hole 4 and placed into the accommodation hole 7 of the die 6 of another molding machine, as shown in FIG. This accommodation hole 7 is a hole with a rectangular cross section, and the length of the rectangle in the longitudinal direction is approximately the diameter of the tablet 1, and the length in the width direction is approximately the thickness of the tablet 1. , the tablet 1 that has been subjected to the primary pressure treatment can be inserted. The tablet l shown by the two-dot chain line inserted into the accommodation hole 7 is pressurized again by the secondary pressurization caused by the mutual forward movement of the pair of punches 8, each of which has its tip facing into the accommodation hole 7. The bulk density is approximately 99%, which is extremely high density. Further, by this second pressurization treatment, the tablet 1 changes from a perfect circle to an oval shape.

In addition, at the time of the said pressure processing, a tablet is heated to 40-50 degreeC and pressurized. This temperature is a temperature at which the resin does not melt, and at the same time, the resin moves easily and pressure molding becomes easy. In addition, since tablet 1 rises to a temperature of about 100°C due to pressure treatment, it is actually
is subjected to pressure treatment while being cooled.

〔effect〕

(1) According to the present invention, after the powdered resin is compressed in the axial direction of the tablet by the first pressure treatment, the powder resin is compressed in the axial direction of the tablet by the second pressure treatment in a direction perpendicular to the direction at the time of the first pressure treatment. ,
In other words, since pressure is applied in the radial direction of the tablet, the second
During the next pressurization, compression molding is performed again including the insufficiently pressurized areas.

Therefore, the effect of increasing the bulk density of the tablet to 99% can be obtained.

(2) According to the above (1), the tablet according to the present invention has a bulk density as high as about 99%, and the air contained inside is extremely small. Therefore, when used as a pancaging material for a transfer resin mold, it is possible to obtain the effect that voids are almost never trapped inside the package.

(3) According to item 2 (2), when the tablet according to the present invention is used as a pancaging material for a semiconductor device,
The moisture resistance of the package is improved and the reliability of the semiconductor device is increased.

(4) Due to the above (]), the tablet according to the present invention has a high density and therefore has high mechanical strength, making it difficult for the tablet to crack or chip when handled, and to pollute the working atmosphere. The effect is that it disappears.

(5) According to (4) above, the use of the tablet according to the present invention does not cause malfunctions due to adhesion of broken tablet pieces to the driving parts of mechanical devices, and also prevents contamination of the working environment, so semiconductor devices that dislike dirt This is preferable for the production of products, and the yield can be improved.

(6) According to (1) to (5) above, according to the present invention, it is possible to obtain a tablet suitable for manufacturing resin-packaged semiconductor devices, and to reduce the cost of semiconductor devices by improving the yield of semiconductor devices. A synergistic effect can be obtained.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. For example, Figures 5 to 7
As shown in the figure, in order to increase the bulk density of the tablet 1, the pressure treatment may be performed more often from the first to the third. That is, as shown in FIG. 5, the powdered resin 2 is subjected to a primary pressure treatment within the accommodation hole 10 of the die 9 by a pair of punches 11. As a result of this first pressure treatment, the bulk density of the tablet 1 becomes approximately 90%. Next, as shown in FIG. 6, the tablet 1 is rotated 90 degrees and subjected to a second pressure treatment. In this state, the bulk density of the tablet 1 is approximately 99%. Therefore, the seventh
As shown in the figure, the tablet 1 was rotated 90 degrees again and then subjected to a tertiary pressure treatment, resulting in a bulk density of 100%.
It becomes a tablet close to

[Application field]

In the following explanation, we have mainly explained the case where the invention made by the present inventor is applied to the field of application which is the background of the invention, which is the manufacturing technology of tablets that are used as materials for transfer resin molds, but the present invention is not limited thereto. .

The present invention can be applied at least to powder solidification technology.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a method for manufacturing Tabreso i according to an embodiment of the present invention, and FIG.
A cross-sectional view showing the next pressurized state.
4 is a perspective view of the tablet, and FIG. 5 is a sectional view showing the first pressurized state of the powder resin in tablet production according to another embodiment of the present invention. Figure 6 also shows the second stage of powdered resin used in tablet manufacturing.
Figure 7 is a cross-sectional view showing the next pressurized state.
It is a sectional view showing the next pressurization state. DESCRIPTION OF SYMBOLS 1...Tablet, 2...Powder resin, 3...Die, 4...Accommodating hole, 5...Punch, 6...Die, 7
...Accommodating hole, 8...Punch, 9...Die, 10.
...Accommodation hole, 11...P Figure 1
Figure 2 Figure 3

Claims (1)

[Claims] 1. A method of molding a powdered resin under pressure with a punch in a die to form a solid tablet, characterized in that the powdered resin is molded by pressure treatment multiple times. Tablet molding method. 2. The tablet molding method according to claim 1, wherein the powdered resin is molded by first pressurization and second pressurization in which at least insufficiently pressurized portions are pressurized.