JP2000246757A - Molding method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the use amt. of a molding material at a time of the molding of a resin seal body while ensuring the good transmission of heating and filling pressure to a resin. SOLUTION: A transfer molding apparatus 20 is equipped with a stick pot 24 formed into a slot shape, the cull 26 formed into a shallow and long groove shape in opposed relation to the stick pot 24 and a plurality of runners connected to the cull 26 at one ends thereof and connected to a cavity 23 at the other ends thereof and having large flow passage areas. Therefore, the use amt. of a resin can be reduced and the heat conductivity to the resin becomes efficient because the cull is shallowly formed and, as a result, the resin can be effectively heated to be melted. By largely forming the cross-sectional area of each of the runners, the pressure of a plunger can be effectively transmitted to the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a molding technique,
A transfer molding technique for transferring a resin as a molding material to a runner and filling a cavity to form a resin molded article.For example, in a manufacturing process of a semiconductor device, a method for molding a resin-sealed body of a resin-sealed package. Regarding effective technology to use.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device, as a transfer molding device for molding a resin-sealed body of a resin-sealed package, there is a resin packaging device disclosed in Japanese Patent No. 2683204. In other words, the resin packaging device has a horizontally long runner that substantially matches the outer shape of the thermosetting resin material that has been formed into a horizontally long shape from a predetermined volume, and along the longitudinal direction of the horizontally long runner after the mold device is opened. A pin for positioning and fixing a lead frame to a plurality of cavities disposed at line-symmetric positions, and a resin packaging by pressure-feeding the thermosetting resin material into the cavities with a mold closing operation of a mold device. The thermosetting resin material is pumped through a shape portion provided on the upper die so as to form a runner thin portion at a portion facing the opening portion of the horizontally long runner, and a female shape portion formed of a gate. A movable runner driven in the horizontal runner so as to be integrated with the lead frame after the completion of the resin packaging accompanying the mold opening operation of the mold apparatus. An ejector pin provided on the upper mold so as to press the integrated object to retrieve outside the mold, and a ejector pin disposed in the shaped portion in order to press the runners thin portion.

[0003] The resin packaging device has the following functions and effects. Since the thermosetting resin material supplied to the horizontally long runner is directly filled into each cavity via each gate as the movable runner performs the pumping operation, the amount of resin used can be reduced. Since the surface area is increased by the shape portion provided on the upper mold, preheating can be easily performed. Also, the amount of resin used can be further reduced by the shape portion.

[0004]

However, it has been found by the present inventors that the above-mentioned resin packaging apparatus has the following problems. In order to secure pressure to the cavity while setting the width of the horizontally long runner to be thin, it is necessary to set the shape of the upper die to be smaller than the width of the movable runner. However, if the shape is set to be thin, sufficient preheating of the resin cannot be ensured. Therefore, if this shape is set wide in order to sufficiently secure the preheating of the resin, the filling pressure of the resin into the cavity is not sufficiently transmitted when the horizontally long runner is set to be thin. Since the shape portion projects from the upper mold, it becomes difficult to process the mold.

An object of the present invention is to provide a molding technique capable of reducing the amount of molding material used in molding a resin-sealed body while ensuring good transmission of heating and filling pressure to a resin. .

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0007]

The outline of a typical invention among the inventions disclosed in the present application is as follows.

[0008] That is, the molding apparatus includes a stick pot formed in a long hole shape, a cull formed in a shallow long groove shape opposed to the stick pot, and one end connected to the cul and the other end formed in a cavity. And a plurality of runners each connected to the tee and having a large channel cross-sectional area.

According to the above-described means, since the cull is formed to be shallow, the amount of the resin used can be reduced, and the heat conduction to the resin becomes efficient. Can be melted. Furthermore, since the cross-sectional area of each runner is formed large, the pressurization of the plunger can be effectively transmitted to the resin.

[0010]

FIG. 1 shows a main part of a transfer molding apparatus according to an embodiment of the present invention, wherein (a) is a side sectional view and (b) is a front sectional view. 2A and 2B show the initial stage of molding, wherein FIG. 2A is a side sectional view and FIG. 2B is a front sectional view. 3A and 3B show the middle of the molding, wherein FIG. 3A is a side sectional view and FIG. 3B is a front sectional view. FIG. 4 is a bottom view showing the upper mold. FIG. 5 shows an object to be sealed with resin.
(A) is a plan view, (b) is a cross-sectional view along the line bb of (a). 6A and 6B show a state after resin sealing. FIG. 6A is a partially cutaway plan view with a part omitted, and FIG. 6B is a cross-sectional view taken along line bb of FIG. FIG. 7 is a perspective view showing a transfer molded body.

In the present embodiment, a molding apparatus according to the present invention is used for molding a resin-sealed body of a semiconductor integrated circuit device (hereinafter, referred to as DIP-IC) having a resin-sealed dual in-line package. It is configured as a transfer molding device.

A resin-sealed object 14 as a work of the transfer molding apparatus according to the present embodiment is configured as shown in FIG. The article to be sealed 14 is provided with a multiple lead frame 1. The multiple lead frame 1 is made of a thin plate made of a copper-based (copper or an alloy thereof) material, and is appropriately punched, pressed or etched. It is integrally molded by means. In the multiple lead frame 1, a plurality of unit lead frames 2 are arranged in a row in the horizontal direction. However, only one unit is shown in the drawings and the following description.

The unit lead frame 2 has a pair of outer frames 3 having positioning holes 3a formed therein.
Are arranged in parallel at a predetermined interval, and the multiple lead frames 1 are respectively extended in a continuous direction. A pair of section frames 4 are arranged between the adjacent unit lead frames 2 and 2 in parallel with each other between the two outer frames 3 and 3 and are integrally built, and substantially formed by these outer frames and section frames. The unit lead frame 2 is formed in a rectangular frame. In each unit lead frame 2, tab suspension leads 7, 7 are respectively disposed in the outer frames 3 and 3 in a right angle direction and integrally protruded therefrom. A tab 8 formed in a substantially square flat plate shape is disposed substantially concentrically with the frame shapes of the outer frames 3 and 3 and the section frames 4 and 4 and is integrally suspended therefrom. The tab 8 is lowered from the surface of the lead 9 group toward the back surface by the thickness of the semiconductor pellet. This is a so-called tab lowering.

A pair of dam members 5 are arranged between the outer frames 3 and 3 so as to extend in a right angle direction on both sides of the tab suspension lead 7, and are integrally built.
A plurality of leads 9 are arranged at equal intervals in the longitudinal direction of the dam members 5, and are integrally formed so as to be parallel to each other and to be orthogonal to the dam member 5. The portion between the adjacent leads 9 and 9 in the dam member 5 substantially constitutes a dam 6 that dams the flow of the resin during molding of the resin sealing body.

The inner end of each lead 9 is disposed so that its tip is close to and surrounds the tab 8, thereby forming an inner portion 9a located inside the resin sealing body. On the other hand, the outer extension of each lead 9 is mechanically connected at its tip to the section frame 4 and constitutes an outer portion 9b located outside the resin sealing body.

A pellet bonding operation and then a wire bonding operation are performed on the multiple lead frames 1 for each unit lead frame 2, and by these operations, the resin-sealed object shown in FIG. The assembly as 14 will be manufactured. These bonding operations are sequentially performed for each unit lead frame 2 by feeding the multiple lead frames 1 in the horizontal direction at a pitch.

First, a semiconductor pellet (hereinafter, referred to as a pellet) 12 as a semiconductor integrated circuit structure manufactured in a so-called previous process in a manufacturing process of a semiconductor device is provided.
Pellet bonding is performed via a bonding layer 11 which is arranged at a substantially central portion on the tab 8 and is formed using a suitable material such as a silver paste. Next, the bonding pad 12a of the pellet 12 and the inner portion 9a of each lead 9 are formed.
The wire 13 formed by using a copper-based, gold-based, or aluminum-based material is wire-bonded between the two by a wire bonding apparatus such as an ultrasonic pressure bonding method. Thus, the integrated circuit formed in the pellet 12 includes the bonding pad 12a, the wire 13, and the lead 9
Is electrically pulled out to the outside via the inner portion 9a and the outer portion 9b.

As shown in FIGS. 1 to 4, the transfer molding apparatus 20 includes a pair of an upper mold 21 and a lower mold 22 which are clamped to each other by a cylinder device or the like.
On the mating surface of the upper mold 21 and the lower mold 22, a plurality of sets of an upper mold cavity concave part 23a and a lower mold cavity concave part 23b are provided.
A pair of members are submerged so as to cooperate with each other to form one cavity 23.

A long hole-shaped pot (hereinafter referred to as a stick pot) 24 for accommodating a tablet 31 as a molding material is opened on the mating surface of the lower mold 22, and the stick pot 24 is moved forward and backward by a cylinder device. The plunger 25 is inserted so that a liquid resin (hereinafter, referred to as a resin) 32 formed by melting the tablet 31 can be fed. The cross-sectional shape of the plunger 25 is formed in a rectangular shape corresponding to the stick pot 24. The tablet 31 is previously formed into a stick shape smaller than the stick pot 24 by squeezing resin powder composed of an epoxy resin, a filler or the like. The volume of the stick-shaped tablet (hereinafter referred to as “stick tablet”) 31 is the cavity 2.
It is set slightly larger than the total volume of all three groups.

On the mating surface of the upper mold 21, a long groove-shaped cull 26 corresponding to the stick pot 24 is submerged at a position facing the stick pot 24, and the center line of the cull 26 is the center line of the stick pot 24. It is parallel to. Long side A of long groove shaped cul 26 is stick pot 2
4 is set slightly larger than the long side a, and the short side B of the long groove-shaped cull 26 is set to be about 1.2 to 1.8 times larger than the short side b of the stick pot 24. . The depth C of the cull 26 is set to be extremely shallow.

As shown in FIG. 4, a plurality of runners 27 are arranged at both sides of the long side of the cull 26 at intervals in the longitudinal direction, and one end of each runner 27 is a gate. 28, each is connected to each cavity 23,
The other end of each runner 27 is connected to the cull 26. By setting the depth D of the runner 27 sufficiently deeper than the depth C of the cull 26, the flow path cross-sectional area of the runner 27 is set sufficiently large. For example, the depth D of the runner 27
Is set to 2 to 5 times the depth C of the cull 26. A terminal 27 a of the end of each runner 27 connected to the cull 26 is closer to the inside than the longer side of the stick pot 24. Therefore, the cross-sectional area of the flow path at the connection portion between the runner 27 and the cull 26 is large despite the cull 26 being formed shallow.

In the area of the cavity group row on the mating surface of the lower mold 22, an escape recess 29 has a rectangular shape slightly larger than the outer shape of the multiple lead frame 1 and has a constant depth substantially equal to its thickness. Has been submerged. That is, the escape recess 29 is configured to allow the thickness of the multiple lead frame 1 to escape.

An upper heat block and a lower heat block are provided outside the upper mold 21 and the lower mold 22, respectively. An electric heater is provided in the upper and lower heat blocks by stick pots 24 in the upper mold 21 and the lower mold 22,
It is laid so as to heat the cull 26, the runner 27 and the stick tablet 31 and the resin 32 in the cavity 23. By this heating, the stick tablet 31 is melted, and the resin formed by melting the stick tablet 31 is reduced to a predetermined viscosity.

Next, a transfer molding method according to an embodiment of the present invention will be described by describing the operation of the transfer molding apparatus according to the above configuration.

When the resin molded body is molded by the transfer molding apparatus 20 according to the above-described configuration, the resin-encapsulated object 14 according to the above-described configuration, which is a work, is inserted into the relief recess 29 of the lower mold 22 as shown in FIG. The pellets 12 in each unit lead frame 2 are accommodated in each cavity 23. Also, a stick tablet 3 in which powdery resin is pressed into a panel shape.
1 is put into the stick pot 24 as shown in FIG.

Subsequently, the upper mold 21 and the lower mold 22 are clamped. The stick tablet 31 put in the stick pot 24 is heated by the heat block and melted to become a liquid resin 32. At this time, since the area of the bottom surface of the cull 26 is set to be larger than the area of the cross section of the stick tablet 31,
The heat is effectively transferred by the cull 26 to efficiently melt and turn into a liquid resin 32.

When the plunger 25 is raised in the stick pot 24 as shown in FIG. 3, the resin 32 in a liquid state pushes the plunger 25 out of the cull 26 laid down opposite the stick pot 24. By force
Each of the runners 27 is extruded, flows through the runner 27, and is filled into each cavity 23 from each gate 28.

When the resin 32 flows into each runner 27 from the stick pot 24 and the cull 26, the short side B of the cull 26 is set to be sufficiently larger than the short side b of the stick pot 24. Immediately after the start of feeding, the resin 32 has a long groove-shaped
The resin 32 is in much contact with the surface and receives much heat conduction, so that the viscosity of the resin 32 is further softened,
Flows into each runner 27 smoothly.

Moreover, since the cross-sectional area of the flow path of each runner 27 is set to be large so that the depth D is large.
Since the flow resistance of each runner 27 is small, the resin 32 that has received the pushing force of the plunger 25 is
7, and the pushing force of the plunger 25 is effectively transmitted to the resin 32. As a result, even though the depth C of the cull 26 is set to be shallow, the resin 32 smoothly flows into each runner 27 and receives the pressing force of the plunger 25 in each runner 27 efficiently. Each cavity 23 is filled through each gate 28 and compacted.

The plunger 25 almost pushes out the resin 32 from the stick pot 24, and
When the resin 32 filled in 3 reaches a so-called substantially barreled state in which the compaction of the resin 32 has been completed, the resin 32 hardly remains in the stick pot 24 as shown in FIG. Moreover, since the depth C of the cull 26 is set to be extremely shallow, the resin 32 hardly remains on the cull 26. That is, the stick pot 24 and the cull 26
All of the resins 32 in the inside are effectively used, and the resin 32 is in a state in which waste is minimized.

After the resin 32 is filled in the cavities 23 and so-called compaction is performed, when the liquid resin 32 is thermally cured, the resin sealing body 15 is formed by the cavities 23. . When the resin sealing body 15 is molded, the upper mold 21 and the lower mold 22 are opened, and the group of the resin sealing bodies 15 is released by the ejector pins. The transfer molded product released from the mold is discharged from the transfer molding device 20 by automatic operation or manual operation of the handler.

The transfer molded body 40 molded as described above is configured as shown in FIG. 6 and FIG. That is, the transfer molded body 40 includes one cull part 46, eight runner parts 47, and the same number of gate parts 48. As shown in FIG. 6, the tab 8, the pellet 12, the inner portion 9 a of the lead 9, and the wire 13 are in a resin-sealed state inside the resin-sealed body 15.

The two multiple lead frames 1, 1 are integrally provided on both sides of the cull portion 46 in a state of being arranged in parallel with each other. One end of the runner 47 is connected to the cull 46 at a right angle, and the other end of the runner 47 is connected to the gate 48. The cull portion 46, the runner portion 47, and the gate portion 48 are portions formed by a solid portion in which the resin 32 is filled in the cull 26, the runner 27, and the gate 28, respectively, and cured. In this state, the cull portion 46
Is thinner than in the case of the conventional example, and the thinner portion is the amount of waste of the resin 32.

The transfer molded body 40 constructed as described above is sent to a molded article separating step. In the molded article separating step, the multiple lead frames 1 in a state in which the resin sealing body 15 is molded by being separated in each gate section 48, and a molded body in a state in which the runner section 47 group is connected to the cull section 46 And are separated.

By setting the depth C of the cull 26 to be small, the thickness of the cull 46 formed by the cull 26 becomes thin. As a result, there is a risk that separation failure may occur during the separation work from the multiple lead frames 1. Therefore, when setting the depth C of the cull 26, it is desirable to consider the point of avoiding this danger.

The multiple lead frame 1 from which the molded body of the cull part and the runner part has been separated in the molded article separating step is cut off the outer frame 3, the section frame 4 and the dam 6 in the lead cutting and forming step. The outer portion 9b of each lead 9 is bent and formed into a gull-wing shape. By the above manufacturing steps, the DIP IC has been manufactured.

According to the above embodiment, the following effects can be obtained.

1) The amount of resin used can be reduced by forming the groove of the long groove facing the stick pot formed in the shape of a long hole to be shallow, so that the effective use efficiency of the resin can be increased. As a result, it is possible to reduce the manufacturing cost of the semiconductor device including the resin-sealed package.

2) By making the cull of the long groove shallow and widening the groove, the heat conduction area with respect to the resin immediately after the start of feeding by the plunger can be comprehensively increased, so that the resin can be heated effectively. The stick tablet and the resin can be efficiently melted and softened.

3) According to the above 2), the liquid resin can be sufficiently heated and softened so as to have a predetermined viscosity, so that the flow of wires and the generation of voids inside the resin sealing body are prevented. In addition, the wear of the culls, runners, gates and cavities can be reduced, and the life of the mold can be extended.

4) By forming the runner connected to the cull having a shallow long groove shape deeply, the flow path resistance at the connection portion with the cull can be suppressed small, so that the plunger is added to the resin flowing through the runner. Pressure can be transmitted effectively. As a result, it is possible to prevent insufficient filling and void formation in the resin sealing body.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Needless to say.

For example, the direction in which the flow path cross-sectional area of the runner is increased is not limited to the vertical direction, but may be the horizontal direction, or both may be used in combination.

The present invention is not limited to the arrangement in which the stick pot is provided in the lower mold and the cull is provided in the upper mold, but the stick pot may be provided in the upper mold and the cull may be provided in the lower mold.

The tablet to be supplied to the stick pot is not limited to a stick tablet formed in a panel shape, but may be a stick tablet formed in a long cylindrical shape. May be used side by side in the longitudinal direction.

In the above description, the invention made mainly by the present inventor is referred to as DIP, which is the application field in which the invention is based.
The case where the present invention is applied to the transfer molding technique used for molding a resin-sealed body of an IC has been described. However, the present invention is not limited to this, and the molding used for molding a resin-sealed body of another IC or transistor. Applicable to all technologies.

[0047]

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

By forming a shallow long groove-shaped cull facing the stick pot formed in a long hole shape, and increasing the cross-sectional area of each of a plurality of runners connected and arranged in the cull in the longitudinal direction, The efficiency of heat conduction to the resin can be increased while reducing the amount of the resin used, and the transmission of the pressing force to the resin can be increased.

[Brief description of the drawings]

FIGS. 1A and 1B show a main part of a transfer molding apparatus according to an embodiment of the present invention, wherein FIG.
Is a front sectional view.

FIG. 2 shows an initial stage of molding, (a) is a side sectional view,
(B) is a front sectional view.

FIGS. 3A and 3B show a molding process, and FIG.
(B) is a front sectional view.

FIG. 4 is a bottom view showing the upper die.

5A and 5B show an object to be sealed with a resin, and FIG.
(B) is sectional drawing which follows the bb line | wire of (a).

6A and 6B show a state after resin sealing, in which FIG. 6A is a partially cutaway plan view with a part omitted, and FIG. 6B is a cross-sectional view taken along line bb of FIG.

FIG. 7 is a perspective view showing a transfer molded body.

[Explanation of symbols]

1 ... multiple lead frame, 2 ... unit lead frame, 3
... Outer frame, 3a ... Positioning hole, 4 ... Section frame, 5 ... Dam member, 6 ... Dam, 7 ... Tab suspension lead, 8 ... Tab, 9
... Lead, 9a ... inner part, 9b ... outer part, 11 ... bonding layer, 12 ... pellet, 12a ... bonding pad, 13 ... wire, 14 ... resin sealed object (work), 15 ... resin sealed body, 20 ... Transfer molding device, 21 ... Upper mold, 22 ... Lower mold, 23 ... Cavity, 2
4, stick pot, 25, plunger, 26, cull, 27, runner, 27a, terminal at connection end, 28, gate, 29, escape recess, 31: stick tablet,
32: resin (molding material), 40: transfer molded body, 46: cull part, 47: runner part, 48: gate part.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Kiyozuka 5-20-1, Josuihonmachi, Kodaira-shi, Tokyo Inside Semiconductor Division, Hitachi, Ltd. (72) Inventor Makoto Nakajima Josui, Kodaira-shi, Tokyo 5-20-1, Honmachi Semiconductor Business Headquarters, Hitachi, Ltd. (72) Inventor Katsuo Arai 5-2-1, Josuihonmachi, Kodaira-shi, Tokyo Semiconductor Business Headquarters, Hitachi, Ltd. (72) Inventor Tetsuya Endo 1-43 Kitakunomoto, Tendo City, Yamagata Prefecture F-term in M-tex Matsumura Corporation 4F206 JA02 JD04 JF01 JM04 JN14 JQ81 5F061 AA01 BA01 CA21 DA03 DA04 DA15

Claims (7)

[Claims] A step of supplying a tablet into a stick pot formed in a long hole shape; a step of supplying and positioning a resin-sealed object between an upper mold and a lower mold; After the lower mold and the mold have been clamped, the liquid resin formed by melting the tablet in the stick pot is advanced by the plunger in the stick pot, and a shallow cull and a flow path having one end connected to the cull are cut off. A step of circulating each of the runners having a large area and filling each of the cavities respectively connected to the other ends of the runners; And a step of releasing the molded body formed by molding. 2. A stick pot formed in a long hole shape, a cull formed in a shallow long groove shape facing the stick pot, and one end connected to the cull and the other end connected to the cavity, respectively. And a plurality of runners having a large flow path cross-sectional area. 3. The molding apparatus according to claim 2, wherein a short side of the cull is set larger than a short side of the stick pot. 4. The molding apparatus according to claim 2, wherein the runner is set deep. 5. The molding apparatus according to claim 2, wherein the width of the runner is set wide. 6. The molding apparatus according to claim 2, wherein a terminal on a cull side of the runner is disposed more inward than an outer edge of the stick pot. 7. The molding apparatus according to claim 2, wherein the stick pot is disposed on a lower die, and the cull is disposed on an upper die.