JPH0729299B2 - Method and apparatus for manufacturing resin tablet for semiconductor encapsulation - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a resin tablet used for semiconductor encapsulation with stable quality and high productivity.

Problems to be Solved by Conventional Techniques and Inventions Resin encapsulation of semiconductor elements is usually performed by transfer molding of synthetic resin such as epoxy resin, but the resin used for this molding is obtained by compression molding the powder. Supplied as a tablet.

Conventionally, this tablet is prepared by kneading a resin composition with a kneader such as a roll and a kneader, cooling and pulverizing the powder, and then adding a predetermined amount of the powder into a cylindrical mold and adding the powder with an upper punch and a lower punch. Although it is made by the compression molding method of pressing, the specific gravity becomes lower than that of the molded product due to the air bubbles entrained in the tablet at the time of compression molding, and when performing transfer molding, the molding efficiency decreases and There is a problem that the obtained resin-sealed semiconductor element has a short moisture resistance life. Therefore, if a tablet with a specific gravity of 90% or more of the molded product is used as a countermeasure, the transfer molding efficiency and the resin encapsulation obtained will be higher than when a tablet with a specific gravity of the tablet of 90% or less of the molded product is used. Since the moisture-proof life of the stopped semiconductor element is improved by several steps, it has been attempted to increase the molding pressure of the tablet to increase the specific gravity of the tablet to 90% or more, particularly about 95% of the molded product.

However, when the pressure during tablet molding is increased, the energy applied to the powder during compression molding changes to heat,
Since heat is generated due to the friction between the tablet and the mold when the tablet is removed from the mold, if the production by this method is continued for a long time, the heat of the mold causes the resin powder to melt and adhere to the mold. If the work continues in this state, the surface of the tablet may be rubbed, an inconvenient part such as a chip may be generated, or the tablet may be cracked. And such a phenomenon is particularly remarkable when a resin having a low viscosity is used, and in order to avoid such inconvenience, this molding operation is often interrupted to cool the mold, Since it is necessary to restart the work after removing the compound adhering to the surface, workability deteriorates remarkably.

Furthermore, recently, when a semiconductor device is sealed by a transfer molding method using an epoxy resin, 5 to 10 plungers are attached to the transfer molding machine, and one plunger can form 2 to 4 cavities. The method of filling (multi-plunger method) came to be adopted,
The tablet used for transfer molding by this method has a shape of 16 mmφ or less and a weight of 2 to 10 g. The tablet used in the conventional method (35 mmφ or more, weight 40 ~
It is very small compared to 500g).

When manufacturing small tablets such as those used in this multi-plunger system, the adhesion of resin to the mold becomes a more serious problem than when manufacturing conventional tablets. That is, if a tablet is manufactured with the resin adhered to the mold, not only will the tablet surface be rubbed and chipped, but the weight of the tablet will decrease each time molding is performed, and the resin will eventually be used for the upper and lower punches. Too much adheres to the mold, making it impossible to mold. In order to avoid such inconvenience, the above-described method, that is, the operation is stopped when the manufactured tablet reaches the minimum allowable weight, and the resin adhered to the upper punch and the lower punch is removed to perform the operation. Since it is restarted, the workability is particularly deteriorated when manufacturing a small tablet.

Under these circumstances, small tablets with a specific gravity of 90% or more of the molded product and a shape of 16 mmφ or less and a weight of about 2 to 10 g can be provided with good quality and stability without attaching resin to the upper and lower punches. It is desired to manufacture.

The present invention has been made in view of the above circumstances, and even when manufacturing a tablet having a high specific gravity and a small shape and weight, a tablet of stable quality can be manufactured with good workability. An object of the present invention is to provide a method for producing a resin tablet for semiconductor encapsulation and an apparatus therefor, which are preferably adopted for producing a tablet of an epoxy resin composition used for stopping.

Means and Actions for Solving Problems The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, when a tablet is produced by compression molding a resin powder, a resin is produced by both punches of a tablet production apparatus. By rotating both punches at the time when the maximum pressure is applied to the powder, especially by rotating the punches at 1/64 to 1/2 rotation, and more preferably in the opposite directions to each other, Since the resin can be prevented from adhering, the present invention has been completed by finding that the above-mentioned various problems caused by the resin adhering can be reliably solved.

Therefore, the present invention is a method of manufacturing a resin tablet for semiconductor encapsulation by filling resin powder into a cylindrical mold and compressing the resin powder with two punches. A method of manufacturing a resin tablet for semiconductor encapsulation, which comprises rotating both punches when pressure is applied, a cylindrical mold filled with resin powder, and a mold which is insertably inserted into the mold. An apparatus for producing a resin tablet for semiconductor encapsulation by inserting two punches into the mold to compress the resin powder, the punch comprising: An apparatus for manufacturing a resin tablet for semiconductor encapsulation, characterized in that a mechanism for rotating both punches at the time of maximum compression of resin powder by both punches is attached. Subjected to.

Hereinafter, the present invention will be described in more detail.

As shown in FIG. 1, for example, a method for manufacturing a resin tablet for semiconductor encapsulation according to the present invention is such that a resin powder 2 is filled in a cylindrical tablet molding die (mold) 1 and each of them is moved in the vertical direction. A compression molding method is adopted in which the resin powder 2 is compressed by an upper punch 3 and a lower punch 4 that are movably arranged at an appropriate pressure to form a tablet. In this case, although FIG. 1 shows that the resin powder is compressed vertically, it does not matter if the resin powder is compressed in the lateral direction as long as it is a device of the type that compresses the resin powder with two punches.
Either one can be adopted.

Here, this molding pressure varies depending on the type and particle size of the powder, but is usually 1 ton / cm ² or more, and when the specific gravity of the tablet is 90% or more of the true specific gravity, it is 2 ton / cm ² or more, and compressed. The formed tablet is taken out by raising the upper punch 3 and then the lower punch 4 in the case of the apparatus shown in FIG.

In the method of the present invention, both punches are rotated when the maximum pressure is applied to the resin powder by the punches. In this case, the rotation speed is preferably 1/64 to 1/2 rotation, particularly 1/32 to 1/6 rotation. If the rotation speed is less than 1/64, resin may adhere to both punches, and if you try to rotate more than 1/2, you will lose the pressure if you apply pressure of 2 tons / cm ² or more. Both punches may stop rotating. Furthermore, it is preferable to rotate these both punches in opposite directions, which can more reliably prevent the resin from adhering to both punches.

When the resin powder is compressed, the compression force is applied only from one punch. For example, in the apparatus shown in FIG. 1, the upper punch 3 may be compressed by lowering only the upper punch 3, but the compression force is applied from both punches. For example, it is more effective to raise the lower punch 4 at the same time so that pressure is applied to the resin powder 2 from both punches 3 and 4.

Further, according to the present invention, the heat generated by compressing the resin powder by rotating both punches can be extremely reduced, but some heat is inevitable. Therefore,
It is preferable to provide a cooling mechanism in the mold to cool the mold.

Next, the material and surface finish of both punches and dies (molds) used in the method of the present invention are not particularly limited, but an epoxy resin composition for semiconductor encapsulation is used to produce an epoxy resin tablet for semiconductor encapsulation. In this case, since the epoxy resin composition for semiconductor encapsulation usually contains 70% or more of very hard quartz powder, both punches and dies will be worn out when used continuously, resulting in Tablets may become unmanufacturable. For this reason, it is not possible to burn 10
If the molding is performed more than ten thousand times, the wear will be severe, and the tablet having the desired shape may not be manufactured.Therefore, when using the epoxy resin composition for semiconductor encapsulation, it is necessary to use a punch and a mold made of a material with little wear. Preferably, a cemented carbide or ceramic having a Vickus hardness of 1000 or more is suitable for this. However, when both punches and the entire die are manufactured using cemented carbide or ceramics with a Vickus hardness of 1000 or more, the hardness is high, but the mechanical strength is weak, so both punches and metal molds are used during continuous production. There are cases where the mold is worn. For this reason, it is preferable that both punch main bodies and the main body of the die be formed of a normal die steel having a Vickus hardness of 1000 or less, and that a cemented carbide or a ceramic having a Vickus hardness of 1000 or more be used only on the surface contacting the resin powder.

In addition, both punches contacting the resin powder, the surface of the die is 4S (JI
It is preferable to finish the surface above S). If it is less than 4S, the finished surface of the tablet may be deteriorated, and the resin powder may adhere to the punch or die.

The draft of the mold is preferably in the range of 0.01 / 100 to 0.5 / 100, more preferably 0.03 / 100 to 0.3 / 100. If the draft is less than 0.01 / 100, not only a great amount of pressure is required to take out the tablet formed by pressing one punch, but also the tablet may be broken at the time of taking out the tablet. On the other hand, when the draft exceeds 0.5 / 100, when the cylindrical tablet is preheated, the tablet is preheated while rotating, but at this time, the mold may fall off from the rotating roller.

Next, the resin powder used in the method of the present invention includes a composition containing a thermosetting resin such as an epoxy resin, a phenol resin, and a urea resin, and is not particularly limited. In order to reduce the variation, it is preferable to adjust the particle size of the resin powder, especially when manufacturing small tablets with a diameter of 16 mmφ or less and a weight of 10 g or less used in the multi-plunger method of transfer molding. is there. In this case, the particle size distribution is such that particles with a size of 16 mesh or larger are 5% or less by weight, particles with a size of 200 mesh or less are 15% or less, especially particles with a size of 16 mesh or larger. Is preferably 2% or less and particles having a particle size of 200 mesh or smaller is 5% or less. If the amount of particles of 16 mesh or larger is more than 5%, the weight variation of the tablet becomes large, and if the amount of particles of 200 mesh or less than 15% is more than 15%, the powder in the hopper is made during tablet production. In some cases, a bridge may occur, and the powder may not be smoothly supplied into the mold, or fine powder may enter the gap between the punch and the mold, causing the vertical movement of the punch to stop moving smoothly.

As an apparatus used for manufacturing the above-mentioned resin tablet,
As shown in FIG. 1, a resin having a cylindrical mold 1 filled with resin powder 2 and two punches 3 and 4 that are arranged so as to be insertable into the mold 1 and that compress the resin powder 2. Any device can be used as long as it is a device for tablet production, but in the device of the present invention, a mechanism for rotating both punches 3 and 4 at the time of maximum compression of the resin powder 2 by both punches 3 and 4. Preferably, a mechanism for rotating both punches 3 and 4 by 1/64 to 1/2 and rotating them in opposite directions is additionally provided. In this case, as the rotating mechanism,
A mechanism as shown in the embodiment described later can be employed.

Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.

First Embodiment FIGS. 2 to 5 show an embodiment of the resin tablet manufacturing apparatus of the present invention, in which 1 is a mold, 2 is resin powder, 3 is an upper punch, and 4 is a lower punch.

The mold 1 is formed in a substantially cylindrical shape and has a Vickus hardness of 1000.
It is composed of a smaller outer wall portion 5 and an inner wall portion 6 having a Vickus hardness of 1000 or more, and its cavity 7 (the inner peripheral surface of the inner wall portion 6) is formed so that the draft is in the range of 0.01 / 100 to 0.5 / 100. Has been done. The mold 1 is held by a mold holder 8, and a cooling pipe 9 is arranged in the mold holder 8 so that the cooling medium 9 flowing through the cooling pipe 9 causes the mold 1 to move.
Is to be cooled.

The upper punch 3 is composed of a large-diameter cylindrical base 10 and a small-diameter cylindrical pressing portion 11 protruding from the lower end surface thereof, while the lower punch 4 has a large-diameter cylindrical base 12 and an upper end surface thereof. The punches 3 and 4 are held by an upper punch holder 14 and a lower punch holder 15, respectively. Here, the bases 10 and 12 of the punches 3 and 4 are made of a material having a Vickus hardness of less than 1000, and the pressing portions 11 and 13 are made of a material having a Vickus hardness of 1000 or more.

An upper shaft 16 is fixed to an upper end surface of the upper punch holder 14, and a joint 17 is arranged on the upper shaft 16, and a projecting tip portion of the joint 17 is arranged in the vertical direction. It is rotatably attached to the projecting tip of a joint 19a fixed to the shaft 18a. A keyway is formed on the outer peripheral wall of the upper shaft 16 along the axial direction, and a keyway is also formed on the inner peripheral wall of the joint 17 along the axial direction. 20a is fitted, whereby the upper shaft 16 and the upper punch holder 14 and the upper punch 3 are moved up and down by the operation of a vertical drive mechanism (not shown), and a rotary drive mechanism (not shown). The shaft 18a rotates by the operation of, and the both joints 19a and
The upper shaft 16, the upper punch holder 14 and the upper punch 3 are adapted to rotate via a, 17 and the key 20a. Further, the lower punch holder 15 is also provided with a joint 21, and the protruding tip end of this joint 21 is provided at the tip of a joint 19b fixed to a shaft body 18b arranged along the vertical direction. It is rotatably attached to the small shaft 22, and the key 20b is fitted into the key grooves formed along the axial direction on the outer peripheral wall of the lower punch holder 15 and the inner peripheral wall of the joint 21, respectively. The lower punch holder 15 and the lower punch 4 held by the lower punch holder 15 move up and down by the operation of the vertical movement drive mechanism (not shown), and the rotation of the shaft 18b that rotates by the operation of the rotation drive mechanism (not shown). Fitting 19b, Small shaft 22, Fitting 21,
The keys 20b are sequentially transmitted and rotated.

Here, the rotation of the upper and lower punches 3 and 4 is 1/64 to 1/2, respectively.
The upper and lower punches 3 and 4 are controlled to rotate when the maximum pressure is applied to the resin powder from the upper and lower punches 3 and 4 while controlling them so that they rotate in opposite directions. ing.

When manufacturing a resin tablet for semiconductor encapsulation using the above-described apparatus, first, the upper and lower punches 3 and 4 are moved up and down to position the upper punch 3 above the cavity 7 of the mold 1 and the lower punch 4. The tip of the pressing portion 13 is inserted into the cavity 7 and positioned below the cavity 7. In this state, the resin powder 2 is introduced into the cavity 7 from the upper end opening of the cavity 7, then the upper punch 3 is lowered to insert the pressing portion 11 into the cavity 7, and the lower punch 4 is raised to raise the cavity. The resin powder 2 in 7 is compressed by these upper and lower punches 3 and 4 to produce a resin tablet.

In this case, when the punches 3 and 4 compress the resin powder 2 at the maximum pressure, the shafts 18a and 18b are 1 / 64th, respectively.
~ 1/2 rotation, the upper punch 3 is connected to the joint 19b, the joint 19b, the key 20a, the upper shaft 16, and the upper punch holder 14 to rotate integrally with the rotation of both shaft bodies 18a, 18b. Through the shaft 22, the joint 21, the key 20b and the lower punch holder 15, the lower punch 4 rotates 1/64 to 1/2 in opposite directions.
As a result, the resin powder is prevented from adhering to the pressing end surfaces of both punches 3 and 4, and small resin tablets can be reliably manufactured without defects such as chipping.

After the tablet is compression-molded in this way, the upper punch 3 rises to come out of the cavity 7, and the lower punch 4 rises to take the tablet out of the cavity 7.

Thus, according to the method for producing a tablet using the apparatus as described above, it is possible to continuously form a tablet having a good appearance by minimizing the variation in quality, and to make the resin powder into the upper and lower punches. Since the adhesion is also prevented, the frequency of cleaning the upper and lower punches and the inside of the mold cavity can be remarkably reduced, and the molding workability and work efficiency are excellent.

The effect of this point will be further shown by the following experimental example.

[Experimental Example 1] Inner diameter is 13 mmφ, gradient in mold is 0.2 / 100, material is Hv1000
The above-mentioned cemented carbide tablet die, upper and lower punches, and a mechanism that the upper punch rotates 1/16 counterclockwise and the lower punch 1/16 clockwise when maximum pressure is applied to the resin powder. Using a tablet manufacturing machine as shown in Fig. 2 to 5, a particle size distribution in which particles of 16 mesh or larger are 2.5% (wt%) and particles of 200 mesh or smaller are 4.8% Epoxy resin composition for semiconductor encapsulation KMC-140 (Shin-Etsu Chemical Co., Ltd.)
2.5g, specific gravity 1.73 (true specific gravity 97
%) Tablets were continuously produced (Example).

Next, with respect to 10000 tablets obtained, variations in specific gravity, height and weight were examined. The results are shown in Table 1.

In addition, as a comparative example, a tablet similar to the above-mentioned example was manufactured under the same conditions and materials as those of the above-mentioned example, using the same tablet-making apparatus as the above-mentioned tablet-making apparatus except that the upper punch and the lower punch did not rotate. As a result, resin adhesion was observed on the upper punch and the lower punch from about 10 shots, and the adhesion amount increased at 50 shots, and further production was impossible.

For the 50 tablets obtained in this comparative example, the same variation as in the above-mentioned example was examined. The results are also shown in Table 1.

[Experimental Example 2] Using the same tablet manufacturing apparatus and materials as in Experimental Example 1,
A tablet similar to that of Experimental Example 1 was prepared in the same manner except that the rotation speeds of the upper punch and the lower punch were changed to those shown in Table 2.
10000 pieces were continuously manufactured, and the adhesion of the resin to the upper punch and the lower punch and the operability (stable operability when pressure was applied to the resin powder at 2 ton / cm ² ) were examined. The results are shown in Table 2.

Second Embodiment FIGS. 6 and 7 show another embodiment of the present invention. The apparatus according to this embodiment is an example of a hydraulic tablet manufacturing apparatus, and in order to rotate the left and right punches, a slip joint is provided on the shafts of the left and right punches to provide a mechanism for imparting rotational movement from the left and right punch rotation axes to the left and right punches. It was done.

That is, in the apparatus shown in FIGS. 6 and 7, the cylindrical mold 1 having the hopper 23 is disposed so as to be movable in the lateral direction, and the resin powder 2
Is introduced into the cavity of the mold 1 from the hopper 23 by its own weight. The left punch 3'and the right punch 4'are connected to pistons 26, 27 slidably arranged on the left and right hydraulic cylinders 24, 25, respectively, via attachments 28, 29 and sliding joints 30, 31. The pistons 25 and 26 are moved to the left and right integrally with the left and right to be inserted into the cavity of the mold 1. The resin powder in the cavity of the mold 1 is compressed by the left and right punches 3'and 4 '. Then, the tablet is formed.

The compression-molded tablet is taken out by ejecting it out of the die 1 by moving the left punch 3'to the left by the operation of the left hydraulic cylinder 24 and moving the die 1 to the right. Be done.

Here, the attachments 28 and 29 are configured such that the shafts 34 and 35 project from the central portions of the distal end surfaces of the cylindrical base portions 32 and 33 whose distal end surfaces are closed, and the slide joints 30 and 31 have the distal end surfaces closed. Two guide elongated holes 38, 39 facing each other along the circumferential direction are formed in the peripheral wall of the cylindrical main portions 36, 37 formed. Then, the tip ends of the pistons 26, 27 are inserted and fixed in the base parts 32, 33 of the attachments 28, 29, and the shafts 34, 35 of these attachments 28, 29 are the main parts 36 of the sliding joints 30, 31. Axis 3 of these joints 30 and 31 in 37
It is inserted so that it can rotate with respect to 4,35, and the shaft
Pins 4 protruding from the outer peripheral surfaces of 34 and 35, offset from each other by 180 °
0,41 are engaged with the guide slots 38,39, and the joints 30,31
Is controlled to rotate 1/64 to 1/2. Furthermore,
The base ends of the left and right punches 3 ', 4'are connected and fixed to the central portions of the front end surfaces of the main parts 36, 37, and joints 42, 43 are fixed to these punches 3', 4 '. The tip ends of 42 and 43 are rotatably attached to the tip ends of joints 46 and 47 fixed to rotary shafts 44 and 45 connected to a rotary drive mechanism (not shown), and the rotary shafts 44 and 45 are The rotation of the punches allows the punches 3 ', 4'to rotate integrally therewith via the joints 46, 47 and the joints 42, 43. In this case, the slide joints 30 and 31 also rotate together with the rotation of the punches 3'and 4 ',
These joints 30,31 are the shafts 34,3 of the attachments 28,29.
By simply sliding the outer peripheral surface of 5 in the circumferential direction, this rotation is not transmitted to the attachments 28 and 29, and therefore the pistons 26 and 27 are prevented from rotating.

The rotation drive mechanism rotates the rotary shafts 44, 45 so that the tips of the left and right punches 3 ', 4'are inserted into the cavities of the mold 1 and the resin powder 2 is rotated by the pistons 26, 25 of the hydraulic cylinders 24, 25.
It is controlled so that it takes place when maximum pressure is applied from the left side punch 3 ', 4'to the left and right punches 3', 4'rotate 1/64 to 1/2 according to the length of the guide slots 38, 39. The left and right punches 3'and 4'are controlled so as to rotate in opposite directions.

Therefore, in the apparatus shown in FIGS. 6 and 7, the resin powder 2 is compressed by the left and right punches 3'and 4'to form tablets as in the apparatus shown in FIGS. Punches 3 ', 4'of 1/64 in opposite directions
~ 1/2 turn, which allows the left and right punches 3 ',
The resin powder is prevented from adhering to the tip surface of 4 '.

Although not shown, the structure of the die and the tip of the left and right punches in the apparatus shown in FIGS. 6 and 7 is the same as that shown in FIG. 3, and the portion in contact with the resin powder is made of a material of Hv1000 or more. , The other parts are made of a material smaller than Hv1000, and the cavity has a draft of 0.01 / 100 to 0.5 / 100 on the tablet extraction side (left side in Fig. 6), and As shown in FIG. 2, the mold is cooled by a refrigerant passing through a cooling pipe arranged in a mold holder.

Further, in the embodiment shown in FIGS. 6 and 7, transmission of rotation from the rotary shafts 44 and 45 to the punches 3'and 4'can be achieved by using gears or belts instead of using the joints as shown in the drawing. Of course, various other changes are possible.

Next, the following experimental examples show the effects of actually manufacturing tablets using the hydraulic tablet manufacturing apparatus as shown in FIGS.

[Experimental Example 3] Inner diameter is 48 mmφ, draft in the mold is 0.2 / 100, and H is on the inner wall.
Molds made of cemented carbide of v1000 or more, left and right punches made of cemented carbide for each pressing part, and the left punch is counterclockwise when the maximum pressure (2.0 ton / cm ₂ ) is applied to the resin powder by the hydraulic cylinder. The same semiconductor encapsulation as that used in Experimental Example 1 was used, using a hydraulic tablet manufacturing device as shown in FIGS. 5 and 6 having a mechanism in which the right punch rotates 1/32 rotation clockwise and the right punch rotates 1/32 clockwise. 100 g by weight using the epoxy resin composition for
10 tablets with a specific gravity of 1.70 (95% of true specific gravity)
000 pieces were continuously produced (Example).

Next, with respect to 10000 tablets obtained, variations in specific gravity, height and weight were examined. The results are shown in Table 3.

As a comparative example, a tablet similar to the above example was manufactured under the same conditions and materials as in the above example, using the same tablet manufacturing apparatus as the above tablet manufacturing apparatus except that the left punch and the right punch did not rotate. As a result, the resin adhered to the pressing parts of the left and right punches at the stage of 20 shot molding, and the adhesion amount increased after 100 shot molding, making it impossible to manufacture a good product.

The 100 tablets obtained in this comparative example were examined for the same variations as in the above-mentioned example. The results are also shown in Table 3.

[Example 4] Using the same tablet manufacturing apparatus and materials as in Example 3,
A tablet similar to that of Experimental Example 3 was prepared in the same manner except that the rotation speeds of the left punch and the right punch were changed to those shown in Table 3.
10000 pieces were continuously produced, and the adhesion of the resin to the left punch and the right punch and the operability (stable operability when a pressure of 2 ton / cm ² was applied to the resin powder) were examined. The results are shown in Table 4.

Third Embodiment FIGS. 8 and 9 show still another embodiment of the present invention, and the manufacturing apparatus according to this embodiment is a rotary type in which a number of molds are attached to a turntable. .

That is, reference numeral 48 in FIG. 8 denotes a rotary main shaft connected to a rotary drive mechanism (not shown), and the rotary main shaft 48 is arranged in the up-down direction, and the rotary main shaft 48 has a mold table 49, The upper punch table 50 and the lower punch table 51 are fixed to the upper and lower portions of the rotary spindle by a predetermined distance.
These tables 49, 50 and 51 can rotate together with the rotation of 48.

A large number of cylindrical molds 1 are attached to the mold table in a state of being separated from each other by a predetermined distance along the circumferential direction, and the upper and lower punch tables 50, 51 are
A large number of upper punches 3 and lower punches 4 are provided above and below the respective dies so as to be vertically movable. An upper pressure roller 52 and a lower pressure roller 53 are arranged above and below the upper and lower punches 3 and 4, respectively, and are in contact with the upper and lower punches.

Here, although not shown, guide rails are provided above the upper pressure roller 52 and below the lower pressure roller 53, and cams are fixed to these guide rails, respectively. The vertical pressing rollers 52, 53 slide along these cam surfaces to allow the vertical punching.
3 and 4 move up and down corresponding to the cam surface. In this case, the vertical movement cycle of the vertical punches 3 and 4 is the 9th.
As shown in the figure, the upper and lower punch tables 50 and 51 rotate together with the rotation of the rotary spindle 48, and the upper and lower punch tables 3 and 4 move in unison with the rotation of the upper and lower punch tables 50 and 51 to move the tablet while moving vertically. These upper and lower punches reach the pressure forming position.
The upper pressure roller 52 and the lower pressure roller 53, which are arranged above and below the upper and lower parts 3 and 4, compress the resin powder through the upper and lower punches 3 and 4, so that the resin powder 2 is separated by these upper and lower punches 3 and 4. It is designed to be pressurized and compressed.

Shafts 54 and 55 are arranged along the vertical direction on the outer sides of the upper and lower punches 3 and 4, and gears 56 and 57 are fixed to the shafts 54 and 55. The motors 58 and 59 connected to the shafts 55 and 55 connect the shafts 54 and 55 and the gear 5 integrally with the shafts 54 and 55.
6, 57 are rotated, and the upper and lower punch tables 50, 51 are rotated, and the upper and lower punches 3, 4 reach the pressing position by the upper and lower pressure rollers 52, 53 and are pressed by these rollers 52, 53. When the resin powder 2 is compressed, the gears 60 and 61 fixed to the upper and lower punches 3 and 4 mesh with the gears 56 and 57 at the time of the maximum compression, and the gears 60 and 61 rotate to be integrated with them. The upper and lower punches 3 and 4 are rotatable, and the upper and lower pressure rollers 52 and 53 are also rotatable. In this case, the rotations of the upper and lower punches 3 and 4 are controlled so as to rotate 1/64 to 1/2 in opposite directions.

Therefore, even with the apparatus of FIG. 8, the resin powder 2 does not adhere to the tips of the upper and lower punches 3 and 4 as in the apparatus of the first and second embodiments described above, and efficient tablet forming is performed. Has been. In this case, in particular, in a rotary tablet manufacturing apparatus of the type in which a large number of molds are attached to the turntable as described above, and the vertical punch moves in the vertical direction with the rotation of this table to manufacture tablets, the upper and lower punches are made of resin. However, since the number of upper and lower punches is large, it takes a long time to remove the adhered resin. However, in the apparatus shown in FIG. 8, it is difficult for the resin to adhere to the upper and lower punches. The frequency of cleaning is greatly reduced and productivity is significantly improved.

In the apparatus shown in FIG. 8, the rotating mechanism at the time of compressing the resin powder of the upper and lower punches is not limited to that shown in the drawing. For example, do not connect the shafts 54 and 55 to the motors 58 and 59,
The upper and lower punches 3, 4 which are arranged immovably and which are integrally rotated (revolved) by the rotation of the upper and lower punch tables 50, 51.
When the gear meshes with the gears 56, 57, the punches 3, 4 may be rotated (rotated) by the revolution of the punches 3, 4.

Further, although the above rotating mechanism rotates the punch using the gear, it may be a mechanism utilizing the pin and the guide groove as shown in FIG. That is, FIG. 10 shows a rotating mechanism of the upper punch (of course, the lower punch can also have a similar mechanism), and a spiral guide groove is formed on the outer peripheral surface of the upper punch 3.
Along with forming 62, a through hole 63 is bored in the upper punch holder 14 along the lateral direction, and a pin 64 is inserted into the through hole 63 so that the tip of the pin 64 projects inward from the inner peripheral surface of the upper punch holder 14. It is inserted and fixed so as to be engaged with the guide groove 62, whereby the pin 64 is guided by the spiral guide groove 62 and the upper punch 3 can rotate when the upper punch 3 descends. .

The mold 1 and the upper and lower punches 3 and 4 can have the same structure as that shown in FIG. 3, and other structures can be variously changed.

Next, the effect of forming a tablet using the apparatus as shown in FIG. 8 will be concretely shown by the following examples.

[Experimental Example 5] The inner diameter is 13 mmφ, the draft in the mold is 0.2 / 100, and the inner wall is H
A die made of cemented carbide of v1000 or more, a top and bottom punch made of cemented carbide of Hv1000 or more in the pressing part, and an upper punch counterclockwise when the maximum pressure (1.3 tons / cm ² ) is applied to the resin powder. Epoxy for semiconductor encapsulation similar to that used in Experimental Example 1 using a rotary tablet manufacturing apparatus as shown in FIG. 8 having a mechanism of 1/32 rotation and lower punch rotating 1/32 clockwise. Using the resin composition, 100,000 tablets having a weight of 3.0 g and a tablet specific gravity of 1.73 (97% of true specific gravity) were continuously produced (Example).

Next, with respect to 100000 tablets obtained, variations in specific gravity, height and weight were examined. The results are shown in Table 5.

As a comparative example, a tablet similar to the above-mentioned example was manufactured under the same conditions and materials as those of the above-mentioned example, using the same tablet-making apparatus as the above-mentioned tablet-making apparatus except that the upper punch and the lower punch did not rotate. As a result, the resin adhered to the pressing parts of the upper and lower punches at the stage of 20 shot molding, and the adhesion amount increased after 100 shot molding, making it impossible to manufacture a good product.

The 100 tablets obtained in this comparative example were examined for the same variations as in the above-mentioned example. The results are also shown in Table 5.

[Experimental Example 6] Using the same tablet manufacturing apparatus and materials as in Experimental Example 5,
A tablet similar to that of Experimental Example 5 was prepared in the same manner except that the rotation speeds of the upper punch and the lower punch were set to the respective rotation speeds shown in Table 6.
10000 pieces were continuously manufactured, and the adhesion of the resin to the upper punch and the lower punch and the operability (stable operability when pressure was applied to the resin powder at 2 ton / cm ² ) were examined. The results are shown in Table 6.

From the results of Table 1, Table 3 and Table 5 described above, the tablets manufactured by the method and apparatus of the present invention have a higher specific gravity, weight, size (higher) than those manufactured by the conventional method and apparatus. S), there was little variation and the quality was stable. Moreover, the appearance of the tablet was also good according to the method and apparatus of the present invention.

It was also confirmed from the results shown in Tables 2, 4, and 6 that the resin adhered to the punch when the rotation speed was low, and the operability deteriorated when the rotation speed was too high.

EFFECTS OF THE INVENTION According to the present invention, the true specific gravity is 90% or more of the molded product, and the shape is 16 mmφ or less, even in the case of producing a small tablet having a weight of about 2 g to 10 g, the surface gloss is excellent and excellent. Quality tablets can be manufactured stably with little quality variation and without sticking resin to the punch. In addition, since there is no sticking of resin to the punch, it is generated by pressing during tablet molding. The generated heat is very small, and therefore, the phenomenon that the resin powder is melted by the heat generated during the continuous operation and does not adhere to the mold is eliminated, and the cleaning frequency of the mold and the punch can be reduced and the workability can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing the outline of a mold part of an apparatus used for carrying out the method of the present invention, FIG. 2 is a schematic side view showing an embodiment of the apparatus of the present invention, and FIG. FIG. 4 is an enlarged cross-sectional view of a die part, FIG. 4 is an enlarged perspective view of an upper punch rotation mechanism of the same example,
FIG. 5 is an enlarged perspective view of a lower punch rotating mechanism of the same example, FIG. 6 is a schematic sectional view showing another embodiment of the device of the present invention, FIG. 7 is an enlarged perspective view of part A of FIG. 6 and FIG. FIG. 9 is a schematic perspective view showing still another embodiment of the present invention, FIG. 9 is a cam diagram for explaining the vertical movement cycle of the upper and lower punches in the same embodiment, and FIG. 10 is another rotation in the embodiment of FIG. It is an expansion perspective view which shows a mechanism. 1 ... Mold (mold), 2 ... Resin powder, 3, 3 '... Top (left) punch, 4, 4' ... Bottom (right) punch.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shinichi Shimizu, 13-1, Isobe, Gunma Prefecture, Annaka City, Isobe Plant, Shin-Etsu Kagaku Kogyo Co., Ltd. 13-1 Shin-Etsu Chemical Co., Ltd. Silicon Silicon Electronic Materials Research Laboratory (72) Inventor Yasuhiko Kato 2-13-1 Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd. Isobe Factory

Claims (6)

[Claims] 1. A method for producing a resin tablet for semiconductor encapsulation by filling resin powder in a cylindrical mold and compressing the resin powder with two punches, wherein the maximum pressure is applied to the resin powder by the both punches. A method for producing a resin tablet for semiconductor encapsulation, which comprises rotating both punches when they are pressed. 2. The manufacturing method according to claim 1, wherein both punches are respectively rotated 1/64 to 1/2. 3. The manufacturing method according to claim 1 or 2, wherein the rotational directions of both punches are opposite to each other. 4. A cylindrical mold filled with resin powder,
Two punches which are arranged so that they can be inserted into the mold and which compress the resin powder in the mold, are inserted into the mold and the resin powder is compressed to seal the semiconductor. An apparatus for manufacturing a resin tablet for semiconductors, which is provided with a mechanism for rotating both punches at the time of maximum compression of the resin powder by the punches. 5. The manufacturing apparatus according to claim 4, wherein the mechanism for rotating both punches is configured to rotate each punch by 1/64 to 1/2. 6. The manufacturing apparatus according to claim 4 or 5, wherein the mechanism for rotating both punches is configured to rotate both punches in opposite directions.