JP3198026B2 - Tablet resin supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tablet resin supply device.

[0002]

2. Description of the Related Art Currently used auto-molding systems for semiconductor resin encapsulation are to set a predetermined amount of tablet resin (compacted resin powder before thermosetting molding by pressing) or an assembly lead frame before a molding process. As long as there is no equipment trouble or running out of supply material, automatic continuous molding work can be performed without using an operator's hand.

Hereinafter, a process of an auto molding system for sealing a semiconductor resin will be described.

First, an assembly lead frame is set in a state of being aligned with a magazine, and the assembly lead frame is transported to a loading frame and set in a mold. In the tablet resin supply device,
Dozens of tablet resins are stocked in a tablet magazine, and the required number of tablet resins for one molding process are taken out of them and sent to the high-frequency preheater, where the tablet resin is preheated (preheated). Then, it is automatically conveyed to the mold for molding (pot for charging the tablet resin).

[0005] Next, after molding and taking out the molded product, mold cleaning (brushing, dust collection) is performed, gate breaks and side burrs are removed, and the products are stored in a vertical magazine.

FIG. 3 shows a part of a mechanism of a tablet resin supply device of a conventional auto-molding system for semiconductor resin sealing, and FIG. 2B shows a plan view of a tablet magazine in the tablet resin supply device. .

Referring to FIG. 3, from the state where dozens of conventional tablet resins are stocked in the tablet resin supply device, the required number of tablet resins for one molding operation is taken out and the high-frequency preheater section is taken out. Will be described.

First, the tablet resin supply device arranges a plurality of the tablet magazines 2 in a circular shape upright and when the tablet resin in one tablet magazine 2 is exhausted,
The system rotates around the circumference, sequentially transports each tablet magazine to the discharge position of the tablet resin, and sequentially sends out the required number of tablet resins from the tablet magazine. In addition, a plurality of columnar tablet resins 1 used for sealing a semiconductor device with a resin are vertically stacked in a cylindrical tablet magazine 2.

Next, in order to carry out only the number of tablet resins 1 used for one molding, the pusher 3 in contact with the lower surface of the lowermost tablet resin 1 of the vertically stacked tablet resins rises vertically. Then, the number of tablet resins 1 used for one molding is moved upward to a position higher than the upper end of the tablet magazine 2.

[0010] Next, the arm 4 holds and holds the tablet resin 1 in the number used for one molding just above the tablet magazine 2. From this state, the pusher 3 moves down to the squeeze position, the arm 4 holding the tablet resin 1 conveyed to the preheater moves horizontally, and automatically conveys the tablet resin 1 to the high frequency preheater.

In addition to the above-described tablet resin holding mechanism, there is also a technique in which a suction mechanism having a vertical movement mechanism is used to suck and hold the tablet resin that has been moved upward and transport it to the pre-heater section (Japanese Patent Laid-Open No. 4-120743). issue).

[0012]

The board mounting method of a surface mount type semiconductor device mainly uses a heating method for the entire package such as reflow, VPS (vapor phase soldering), and flow soldering. Package cracking during mounting due to moisture absorption
It is regarded as a problem, and various countermeasures are taken.

One of the measures against package crack resistance is to improve the molding resin. In order to improve the package crack resistance, the physical properties required of the mold resin are improved adhesion, higher strength, and lower moisture absorption.

At present, the molding resin is E as a base resin.
The mainstream is one using an OCN (orthocresol novolac) type epoxy resin (hereinafter referred to as “EOCN-based resin”), but an improved resin is a biphenyl-type epoxy resin having a lower melt viscosity (hereinafter referred to as “biphenyl-based resin”). Resin ”).

As a result, the biphenyl-based resin has a good adhesion to the insert (a chip or a lead frame) by EOCN.
It is higher than the base resin. In addition, by using this high fluidity (low melt viscosity) to increase the filler loading,
High strength and low moisture absorption are possible. Therefore, in order to improve package crack resistance, the use of biphenyl-based resins in surface-mounted semiconductor devices will increase in the future.

FIG. 4 shows the mechanism of the tablet resin supply device when biphenyl resin tablets are vertically stacked in a tablet magazine. The biphenyl-based resin has a crystal structure, and when the crystal structure is broken by pressure or heat, the viscosity suddenly decreases. For this reason, if the biphenyl-based resin tablet is left in the tablet magazine for a relatively long time (for example, about 5 hours), the pusher 3 moves downward to a position as shown in FIG. Where the tablet resin conveyed to the preheater and the tablet resin 1 waiting for the next mold are separated, the vertically stacked tablet resins 1 are adhered to each other, and the arm holding the tablet resin 1 in the state of being adhered remains. 4
Is moved horizontally, the tablet resin 1 comes into contact with the tablet magazine 2, causing a problem on the auto-molding device, which is a problem. However, the adhesion between the tablet resins 1 is not a phenomenon limited to the biphenyl-based resin.

The adhesion of the tablet resins 1 of biphenyl resin vertically stacked in the tablet magazine 2 is affected by the temperature and humidity in the storage of the tablet magazine 2, the tablet compression ratio, the tablet compression ratio, and the like. After investigating and testing the effect of the contact surface roughness, the following Table 1
And the results shown in Table 4 were obtained.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table 4]

Temperature dependence of tablet adhesion (relative humidity 5
Table 1 showing the dependence of the tablet adhesion on humidity (at a relative temperature of 30 ° C.), Table 2 showing the tablet compression ratio dependence of the tablet adhesion, and surface roughness of the tablet contact portion. As is clear from Table 4 showing the degree dependency, in the bonding between phenyl resin tablets, there is no effect on changes in tablet compression ratio or tablet contact surface roughness, but effects on changes in temperature and humidity. Is seen.

Assuming that the device stops due to device trouble, running out of supply material, etc., and the tablet resin is left in the tablet magazine for a certain period of time, even if the tablet resin is vertically stacked in the tablet magazine for 24 hours, If the goal is to avoid problems caused by contact between tablet resins, set the tablet magazine storage temperature to 2
It is necessary to control the temperature to 0 ° C. or less and the humidity to 50% or less.

The actual temperature in the tablet magazine storage
When the humidity is measured, it becomes approximately 27 ° C / 50%,
It is necessary to lower the temperature in the tablet magazine storage by 7 ° C. or more. However, the temperature inside the tablet magazine storage
Reducing the temperature by more than ℃ requires a large capital investment and is not feasible.

The present invention provides a tablet resin supply device for an auto molding system for semiconductor resin encapsulation in which, when tablet resins are vertically stacked in a tablet magazine, the tablet resins adhere to each other and no trouble occurs on the auto molding device. The purpose is to do so.

[0026]

According to a first aspect of the present invention, there is provided a tablet resin supply apparatus comprising: a tablet magazine for accommodating a plurality of tablet resins, the tablet magazine having an inlet and an outlet for tablet resin; First moving means for moving the plurality of tablet resins to the discharge port, and when the tablet resin is moved by the first moving means provided on the side wall of the tablet magazine, one tablet resin is transferred to the tablet Second moving means for moving the tablet resin in contact with the resin in different directions on the same plane.

According to a second aspect of the present invention, there is provided a tablet resin supply device according to the present invention, wherein the second moving means is provided at a plurality of predetermined intervals and projects toward the center of the tablet magazine. 2. The tablet resin supply device according to claim 1, wherein said adjacent jigs face each other with respect to a center of said tablet magazine.

[0028]

According to the above construction, the second moving means moves the contact surface between the tablet resin at the end on the side produced from the tablet magazine and the tablet resin in contact with the tablet by the second moving means.
The shearing force acts to separate the tablet resins from each other.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment.

FIG. 1 is a view showing a tablet resin conveying process using the tablet resin supply device of the present invention, and FIG. 2A is a plan view of a tablet magazine of the present invention.

In FIG. 1, 1 is a tablet resin, 2 is a tablet magazine, 3 is a pusher, 4 is an arm,
a denotes a disk-shaped rotatable first pulley fixed by a central axis, and 5b denotes a disk-shaped rotatable second pulley fixed by a central axis.

Hereinafter, a process of removing the tablet resin from the tablet magazine using the tablet resin supply device of the present invention will be described with reference to FIG.

The tablet resin supply device according to the present invention comprises:
First, a plurality of columnar tablet resins 1 used for sealing a semiconductor device with a resin are vertically stacked on a cylindrical tablet magazine 2. In addition, as shown in FIG. 2A, variations in the tablet resin outer diameter (± 0.3 to ± 0.0.
5 mm), the inner diameter of the tablet magazine 2 is designed to be 1-2 mm larger than the outer shape of the tablet resin. Therefore, the tablet resin 1 can easily move in the tablet magazine 2 in the horizontal direction.

In this embodiment, FIGS. 1 and 2 (a)
As shown in the figure, a first pulley 5a is provided near the discharge port of the tablet magazine 2, and the second pulley 5a is provided below the first pulley 5a at an interval in a range of 1 to 2 times the thickness of the tablet resin 1.
b is provided at a position facing the first pulley 5a. Since the tablet size (height, diameter) differs depending on the type of the tablet resin 1 and the type of the semiconductor device to be resin-sealed, when the tablet resin 1 passes through the first and second pulleys 5a and 5b, the tablet resin 1 and 2 so that the horizontal movement of the left and right 1 is continuous and moves without resistance.
The distance between the pulleys 5a and 5b and the protrusion amount of the pulley tip are adjusted.

The material of the first pulley 5a and the second pulley 5b is such that the first and second pulleys 5a and 5b are deformed or chipped by contact with the tablet resin 1 and the first pulley 5 5a and the second pulley 5b are mixed so as not to affect the reliability of the semiconductor device. It is also desirable to reduce the weight as much as possible. In this embodiment, stainless steel is used.

Further, in order to reduce the moving speed of the tablet resin 1 in the horizontal direction and to prevent chipping or cracking of the tablet resin, the first and second pulleys 5a, 5b
It is desirable to increase the diameter of the tablet magazine 2, but if it is too large, it will come into contact with the adjacent tablet magazine 2 (not shown). In the present embodiment, first and second pulleys 5a and 5b having a diameter of 20 mm and a width of 6 mm are used, and the distance between the center of the first pulley 5a and the center of the second pulley 5b is approximately 1 mm of the tablet resin. 0.5 times.

As shown in FIGS. 1A to 1D, the same number of tablet resins 1 used for one molding
When the pusher 3 in contact with the lower surface of the lowermost tablet resin 1 is lifted vertically in order to carry out, the tablet resin 1 moves upward to a position higher than the upper end of the outlet of the tablet magazine 2. And tablet resin 1
Rises and passes through the second pulley 5b, the tablet resin 1 is horizontally moved by the rotating second pulley 5b, and is pushed by the inner wall of the tablet magazine 2 on the opposite side of the second pulley 5b. While moving up.

Next, when the tablet resin 1 further rises and passes through the first pulley 5a, the tablet resin 1 moves in the horizontal direction by the rotating first pulley 5a, and is moved in the opposite direction to the first pulley 5a. It moves upward while being pressed by the inner wall of the tablet magazine 2 on the side. At this time, the tablet resin 1 that is in contact with the tablet resin 1 that is moving in the horizontal direction by the first pulley 5a is in the opposite direction to the tablet resin 1 that is in contact with the first pulley 5a by the second pulley 5b. Since the tablet resin 1 is about to move, a shearing force acts on the adhesive surface of the tablet resin 1 and the tablet resin 1 is separated.

As described above, even if the tablet resins 1 of biphenyl type or the like are vertically stacked in the tablet magazine 2 and the tablet resins 1 are adhered to each other, the tablet resins 1 move left and right in the horizontal direction, and A shearing force is applied to the bonded portion to separate the bonded tablet resins 1 from each other, and the tablet resin 1 is carried out of the tablet magazine 2 by the arm 4.

According to the present invention, as a jig for horizontally moving the tablet resin, in addition to the first and second pulleys 5a and 5b, a wedge-shaped jig which projects gradually upward in the upward direction of the tablet magazine 2 is used. The jig may be installed on the inner wall of the tablet magazine 2 as long as it has a jig that allows the tablet resin 1 to rise inside the tablet magazine 2 without resistance and to move horizontally. Further, the tablet resin is not limited to the biphenyl-based resin, but may be any as long as the tablet resins that come into contact with each other in a vertically stacked state are adhered to each other.

[0041]

As described in detail above, by using the present invention according to the first and second aspects, a shearing force can be applied to the adhered tablet resins to separate them. In the case where the present invention described in claim 2 is used, a plurality of jigs projecting inward from the inner wall of the tablet magazine are alternately arranged at a certain height interval so as to face the center of the tablet magazine. Thereby, a shearing force can be more reliably applied as compared with the case where only one jig is used.

[0042]

[Table 5]

As a result, as shown in Table 5, even when the tablets, such as biphenyl resin, are left in a tablet magazine, they can be separated mechanically even if they adhere to each other. Problems on the molding device do not occur.

[Brief description of the drawings]

FIG. 1 is a view showing a tablet resin conveying step of the present invention.

FIG. 2A is a plan view of a tablet magazine according to an embodiment of the present invention, and FIG. 2B is a plan view of a conventional tablet magazine.

FIG. 3 is a view showing a conventional tablet resin conveying process.

FIG. 4 is a diagram for explaining a problem of a conventional tablet resin conveying process.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 tablet resin 2 tablet magazine 3 pusher 4 arm 5 a first pulley 5 b second pulley

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/18 B29C 31/04 H01L 21/56

Claims (2)

(57) [Claims] 1. A tablet magazine for accommodating a plurality of tablet resins, the tablet magazine having an inlet and an outlet for tablet resin, and a first moving means for moving the plurality of tablet resins from the inlet to the outlet. A step of moving one tablet resin in a different direction on the same plane with respect to the tablet resin in contact with the tablet resin when the tablet resin is moved by the first moving means provided on the tablet magazine side wall; 2. A tablet resin supply device, comprising: 2. The second moving means is a jig provided at a plurality of predetermined intervals and protruding toward the center of the tablet magazine, and the adjacent jigs are connected to each other by the tablet. The tablet resin supply device according to claim 1, wherein the tablet resin supply device faces the center of the magazine.