JPH05293846A - Molding apparatus - Google Patents

Abstract

PURPOSE:To provide a multi-pot type transfer molding apparatus constituted so that the injection pressures of the resin in respective cavities are made uniform and no resin flash is formed on the end surface of a multiple lead frame. CONSTITUTION:Runners 27 are mutually connected by connection runners 27A and the connection runners 27A are arranged so as to be adjacent to the end surfaces of multiple lead frames. By this constitution, the pressures of the resin in respective cavities 23 become uniform by the connection runners 27A. Since the connection runner parts are formed on the end surfaces of the multiple lead frames, no resin flash is formed on the end surfaces of the frames.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to resin molding technology,
A transfer molding technique for transferring a resin as a molding material melted in a pot and a cull region to a cavity through a runner and a gate. For example, it is effective for molding a resin-sealed package in a semiconductor device manufacturing process. Related technology.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, as a transfer molding apparatus for molding a resin-sealed package,
Multiple pots into which tablets of molding material are put,
Heating means for heating and melting the tablets placed in these pots, a plurality of plungers fitted in the pots and crushing the tablets to press-feed the molding material formed by melting the tablets, and each pot A plurality of culs arranged so as to face each other, a plurality of runners fluidly connected to each cull, and a plurality of cavities fluidly connected to each runner. Some have and.

In this transfer molding apparatus, a tablet placed in each pot is melted in the pot and cull regions in a state where the semiconductor pellets and the leads, which are objects to be sealed with resin, are housed in each cavity. .. Then, a resin (hereinafter, referred to as a resin) as a molding material formed by melting the tablet is transferred to each cavity through each runner and gate by each plunger, so that the semiconductor pellet and the lead are resin-molded in each cavity. The encapsulating package is configured to be molded.

As an example in which such a multi-pot type transfer molding technique is described, Japanese Patent Laid-Open No. 61-61
-292330, JP-B-57-35576, JP-A-56-108236, and JP-A-6-
No. 2-122136.

[0005]

In the transfer molding of the multi-pot method as described above, if the weight of the tablet varies, the injection pressure of the resin fed into each cavity also varies. However, there is a problem that the resin sealing as described above is not uniformly molded.

In view of this, Japanese Patent Application Laid-Open No. 61-292330 discloses a technique in which a resin is injected into each cavity at a uniform pressure by connecting culls with a runner.

Further, in order to make the injection pressure of the resin uniform, a transfer molding device configured to push the plunger via a spring and the plungers are independently driven so that the injection pressure is uniform. There is a transfer molding device that can be used.

[0008] However, all of these transfer molding apparatuses have a problem that the mold is made large, the structure is complicated, and the cost is increased.

By the way, in the conventional transfer molding apparatus, when molding the multiple lead frame, the resin flowing through the runner and the gate leaks through a gap existing between the end surface of the lead frame and the mold, so that the lead is formed. The resin adheres to the gate-side end surface of the frame to form a resin burr.

If this resin burr drops into the cutting / molding machine in the cutting / molding step, which is the next step, it causes problems such as resin dents and resin scraps, and causes transport problems. ..

An object of the present invention is to provide a molding apparatus which can make the injection pressure of the resin in each cavity uniform.

Another object of the present invention is to prevent the formation of resin burrs on the end face on the gate side of a multiple lead frame having semiconductor pellets and leads, which are objects to be sealed with resin. I am trying.

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

[0014]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, a plurality of pots into which tablets of the molding material are placed, heating means for heating and melting the tablets placed in these pots, and tablets which are inserted into the pots and crushed to form tablets. A plurality of plungers for pumping the molten molding material, a plurality of culls arranged so as to face each pot, and a plurality of claws fluidly connected to each cull. In a molding apparatus including a runner and a plurality of cavities fluidly connected to each runner, the plurality of runners are characterized in that the runners are connected to each other by a connecting runner.

The connecting runner is arranged so as to be adjacent to an end face of the multiple lead frame in which the semiconductor pellets and the leads, which are the resin-sealed objects, are housed in the cavity. ..

[0017]

According to the above-mentioned means, since the runners are connected to each other by the connecting runners, all pots, culls,
The pressure of the runner, the connecting runner, the gate and the resin in the cavity becomes uniform. As a result, the injection pressure of the resin in each cavity becomes uniform without variation, and a uniform molded product can be obtained for each cavity.

When the connecting runner is arranged so as to be adjacent to the end face of the multiple lead frame in which the semiconductor pellets and the leads, which are the resin-sealed objects, are housed in the cavity, the multiple runners are formed at the time of molding. A connecting runner portion is formed on the end surface of the lead frame. As a result, the resin burr is not formed on the end surface of the multiple lead frame, and the connecting runner part formed by being attached to the end surface of the multiple lead frame removes the resin burr at the time of the gate break after molding. It can be easily removed without forming.

[0019]

1 is a plan view showing a lower die of a transfer molding apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged partial front sectional view showing a main part of a transfer molding apparatus according to an embodiment of the present invention. 3 is a perspective view showing a tablet, and FIG.
(A), (b) is a top view and b- which show a to-be-sealed object.
Sectional drawing which follows the b line, FIG.5 (a), (b) is a partially omitted enlarged partial plan view which shows after resin sealing, and sectional drawing which follows the bb line, FIG.6 is a perspective view which shows a molded object. It is a figure.

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

In the present embodiment, the resin-sealed object 14 as a work of this transfer molding apparatus is as shown in FIG.
It is configured as shown in (a) and (b),
The resin-sealed object 14 includes the multiple lead frame 1. The multiple lead frame 1 is made of a thin plate made of a copper-based (copper or its alloy) material and is integrally formed by an appropriate means such as punching press working or etching working. In this multiple lead frame 1, a plurality of unit lead frames 2 are arranged side by side in a row in the lateral direction. However, only one unit is shown in the drawing.

The unit lead frame 2 is provided with a pair of outer frames 3 each having a positioning hole 3a. Both outer frames 3 are arranged in parallel at a predetermined interval so that the multiple lead frame 1 is continuous. It is extended in a series in the direction to do. A pair of section frames 4 are disposed between the unit lead frames 2 and 2 adjacent to each other so as to be parallel to each other between the outer frames 3 and 3 and are integrally installed. The unit lead frame 2 is formed in a rectangular frame.

In each of the unit lead frames 2, tab suspension leads 7, 7 are arranged at right angles to both outer frames 3 and 3 and integrally project therefrom, and the tips of the tab suspension leads 7, 7 are integrally formed. A tab 8 formed in a substantially square flat plate shape is disposed between the outer frames 3 and 3 and the section frames 4 and 4 so as to be substantially concentric with the frame and is integrally suspended. The tab 8 is lowered toward the back surface by the thickness of the semiconductor pellet (described later) from the surface of a group of leads 9 described later (so-called tab lowering).

A pair of dam members 5 are arranged between the outer frames 3 and 3 so as to extend at right angles on both sides of the tab suspension lead 7 and are integrally erected.
A plurality of leads 9 are arranged at equal intervals in the longitudinal direction on both dam members 5, 5, and are integrally projected so as to be parallel to each other and orthogonal to the dam member 5.

The inner ends of the leads 9 are arranged such that the tips are close to the tabs 8 and surround the tabs 8 so that the inner parts 9 are located inside the resin-sealed package described later.
a respectively. On the other hand, the outer extension of each lead 9 has its tip mechanically connected to the section frame 4 and constitutes an outer portion 9b located outside the resin-sealed package described later.

The portion of the dam member 5 between the adjacent leads 9 and 9 substantially constitutes a dam 6 for stopping the flow of the resin at the time of molding a package which will be described later.

The multiple lead frame 1 constructed as described above is subjected to pellet bonding work and then wire bonding work for each unit lead frame 2 (not shown). As a result of these operations,
As a result, the assembly as the resin-sealed object 14 which is the work as shown in (a) and (b) is manufactured.
These bonding operations are sequentially carried out for each unit lead frame 2 by laterally pitching multiple lead frames.

First, by pellet bonding work,
In a so-called pre-process in the manufacturing process of a semiconductor device, a pellet 12 as a semiconductor integrated circuit structure in which a bipolar type integrated circuit element (not shown) is formed is formed in a substantially central portion on a tab 8 in each unit lead frame 2. And are fixed to each other via a bonding layer 11 formed of an appropriate material such as silver paste.

The silver paste is formed by mixing an epoxy resin adhesive, a curing accelerator, and a solvent with silver powder. After the silver paste applied onto the lead frame is pressed with the pellets, The bonding layer 11 is formed by being cured at an appropriate temperature.

Between the bonding pad 12a of the pellet 12 fixedly bonded to the tab 8 and the inner portion 9a of each lead 9 in the unit lead frame 2, a copper-based, gold-based or aluminum-based material is used. The wire 13 formed and used is bridged by wire-bonding both ends thereof by using an appropriate wire-bonding device (not shown) such as an ultrasonic thermocompression bonding type. ..

As a result, the integrated circuit built in the pellet 12 includes the bonding pad 12a and the wire 1.
3, the inner portion 9a of the lead 9 and the outer portion 9b electrically lead to the outside.

In the multiple lead frame as the work which is the resin-sealed object 14 pelletized and wire-bonded in this way, a package group for resin-sealing each unit lead frame is as follows. Simultaneous molding is performed on a unit lead frame group using the configured transfer molding device.

The transfer molding apparatus 20 according to this embodiment.
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 (not shown). A plurality of sets of upper mold cavity recesses 23a and lower mold cavity recesses 23b are formed on the mating surface of the upper mold 21 and the lower mold 22, and a pair of members cooperate with each other to form one cavity 23. It is buried in.

When the resin-sealed object 14 as a work having the above structure is used to transfer-mold a resin-sealed package, each cavity 23 in the upper mold 21 and the lower mold 22 has a multiple lead frame 1. The unit lead frames 2 are arranged so as to correspond to the spaces between the pair of dam members 5 and 5, respectively.

A plurality of pots 2 are provided on the mating surface of the upper mold 21.
4 are arranged so as to correspond to a plurality of cavities 23, respectively, and a plunger 25 that is advanced and retracted by a cylinder device (not shown) is provided in each pot 24.
Are squeezed into a tablet 41 (described later) as a molding material, and are inserted so that a liquid resin (hereinafter, referred to as a resin) obtained by melting the tablet can be fed.

A plurality of culls 26 are provided on the mating surface of the lower mold 22.
Are arranged at positions facing the respective pots 24 and are buried therein, and a pair of runners 27 are respectively connected to the respective culls 26 so as to be opposed to each other with the culls 26 sandwiched therebetween.

The other end of each runner 27 is connected to each lower cavity recess 23b.
7 is provided at the connecting portion between the cavity 7 and the cavity recess 23b.
Are formed so that the resin can be injected into the cavity 23.

A connecting runner 27 is provided on both sides of the cull 26.
One A is formed for each, and each connected runner 2
Reference numeral 7 is orthogonal to a plurality of runners 27 arranged in parallel, and is formed so as to connect the runners 27 to each other.

Further, the relief recess 2 is formed on the mating surface of the lower mold 22.
In order to allow the lead frame 9 to escape the thickness of the lead frame, the rectangle 9 is slightly larger than the outer shape of the multiple lead frame 1 and is recessed at a constant depth of a dimension substantially equal to the thickness.

The connecting runner 27A is disposed adjacent to the side of the escape recess 29, and the connecting runner 27A and the escape recess 29 communicate with each other.

An upper heat block 31 and a lower heat block 32 are provided outside the upper mold 21 and the lower mold 22, respectively, and the upper and lower heat blocks 31, 32 are provided.
An electric heater 33 is laid so as to heat the pots, culls, runners and tablets and resins in the cavities of the upper mold 21 and the lower mold 22. By this heating, the tablets are melted, and the resin formed by melting the tablets is reduced to a predetermined viscosity.

In the transfer molding method in which the transfer molding apparatus 20 is used, a tablet 41 made of epoxy resin or the like (hereinafter referred to as resin) as a molding material is used.

As shown in FIG. 3, the tablet 41 is formed by compacting a powdery resin 42 into a cylindrical shape, and has a diameter slightly smaller than the inner diameter of the pot 24 of the transfer molding apparatus 20. It is formed to have an outer diameter, is put into the pot 24, and is heated and melted.

Next, the operation will be described. At the time of transfer molding, the resin-sealed object 1 according to the above-described structure which is a work
4 is arranged so that the multiple lead frames 1 are housed in the escape recesses 29 that are buried in the lower mold 22, and the pellets 12 of each unit lead frame 2 are housed in each cavity 23. Is set.

Subsequently, the tablets 41 are put into the pots 24, respectively, and the upper die 21 and the lower die 22 are clamped.

The tablet 41 put in the pot 24 is crushed by the plunger 25. In addition, after being placed in the pot 24, the upper and lower heat blocks 31, 3 arranged outside the upper mold 21 and the lower mold 22, respectively.
Since it is heated by 2, the tablet 41 is melted and liquefied.

Then, the tablet 43 is crushed, and the resin 43 liquefied by being heated is heated from each cull 26 facing each pot 24 to the plunger 25.
Each runner 27 and connecting runner 27A by the pushing force of
And it is sent to each cavity 23 through the gate 28 and is filled into each cavity 23.

At this time, each runner 27 is connected to the runner 27.
Since they are connected to each other at A, the pressures of all pots 24, culls 26, runners 27, connection runners 27A, gates 28, and resin in the cavities 23 become uniform.
Therefore, the pressure of the resin injected into each cavity 23 becomes uniform, so that the resin-sealed molded product in each cavity 23 is uniform in each cavity 23.

After the injection, when the liquid resin 43 is thermoset and the resin-sealed package 15 is molded, the upper mold 21 and the lower mold 22 are opened, and the packages are ejected by ejector pins (not shown). Fifteen groups are released. In this way, as shown in FIG. 5, the multiple lead frame 1 as a work in which the group of packages 15 is molded is detached from the transfer molding apparatus 20.

Then, inside the resin-molded package 15, as shown in FIG. 5, the tab 8, the pellet 12, the inner portion 9a of the lead 9 and the wire 13 are resin-sealed. It will be.

FIG. 6 shows the molded body 100 detached from the transfer molding apparatus 20. In the multiple leadframe 1 in the molded body 100 shown in FIG. 6, three unit leadframes are arranged in series and integrally connected, and each unit leadframe has a substantially rectangular flat plate shape. The respective packages 15 are molded so that the pellets in which the integrated circuits are built are resin-sealed.

Further, in the molded body 100, three cull portions 126 formed as the feeding passage portions and each cull portion 126 are provided.
6 runner parts 127 connected in pairs to the cull part 12
Two runner portions 127A arranged on both sides of 6 to connect adjacent runner portions 127, and a runner portion 12
7 and the same number of gate portions 128 are provided. The cull portion, the runner portion, the connecting runner portion, and the gate portion are cull 26,
The runner 27, the connecting runner 27A, and the gate 28 are resin-molded portions molded by filling the resin.

A plurality of runner portions 127 connected to each cull portion 126 so as to face each other are arranged in parallel with each other, and the other end of each runner portion 127 is connected to the gate portion 128. The gate portions 128 are connected so that the short sides located inside of the package 15 face outward, and are arranged below the multiple lead frame 1.

The connecting runner portion 127A is arranged orthogonal to the runner portion 127 to connect the runner portions 127 to each other, and one runner portion is formed on each side with the cull portion 126 interposed therebetween. The side surface of the connecting runner portion 127A is connected to the end surface of the cull portion 126 side.

As described above, since the connecting runner portion 127A is connected to the end surface of the multiple lead frame 1 on the side of the cull portion 126, the molded body 100 according to the present invention has the end surface of the multiple lead frame 1. No resin burr is formed on. That is, the resin burr is integrated with the connecting runner portion 127A and is substantially absorbed.

After the molded body 100 is detached from the transfer molding device 20, the resin feed passage portion formed by the cull portion 126, the runner portion 127, the connecting runner portion 127A and the gate portion 128 is removed by the molded product separating device. Separated from the continuous lead frame 1. As a result, the connecting runner portion 127A on the side surface of the multiple lead frame 1 is also separated, so that no resin flash remains on the end surface of the multiple lead frame 1.

Thereafter, in the lead cutting step, the outer frame 3, the section frame 4, and the dam 6 are cut off from the multiple lead frame 1, and the outer portion 9b of each lead 9 is bent downward. At this time, since the resin burr is not formed on the end surface of the multiple lead frame 1, it is possible to prevent the occurrence of defects and conveyance troubles due to resin dents and resin scraps in the cutting and molding process.

DIP / IC1 manufactured in this way
The outer portions 9b of the leads 6 are inserted into the through holes of the printed wiring board, respectively, and are electrically and mechanically connected by solder fillets.

According to the above embodiment, the following effects can be obtained. Since the runners are connected to each other by the connecting runner, the pressure of the resin in all pots, culls, runners, gates, and cavities becomes uniform. Therefore, the injection pressure of the resin in each cavity becomes equal, and a uniform molded product is obtained in each cavity.

Since the connecting runner for connecting the runners is arranged so as to be adjacent to the end face on the gate side of the multiple lead frame, the connecting runner portion is formed at the end face of the multiple lead frame during molding. It Therefore, no resin burr is formed on the end surface of the multiple lead frame.

As described above, the connecting runner portion formed on the end surface of the multiple lead frame can be easily removed without forming a resin burr at the time of the gate break after the molding.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the pot is not limited to the upper mold and the cull is arranged in the lower mold, but the pot is arranged in the lower mold and the cull is replaced in the upper mold. May be.

The concrete shapes and structures of the upper and lower molds, pots, plungers, runners, gates, cavities, and other constituent elements are not limited to the above-mentioned configurations, but it is desirable to appropriately select them according to molding conditions and the like. ..

In a molding apparatus having a plurality of pots and a plurality of cavities, each of which is directly connected to the pot, the gates for injecting the resin of the respective cavities are connected to each other by connecting paths. It may be configured to be fluidly connected. Also in this case, the injection pressures of the cavities are equalized, so that a homogeneous molded product can be obtained.

In the above description, the invention mainly made by the present inventor is the field of application which is the background of the invention.
The case where the present invention is applied to a molding device used for molding a resin-sealed package of an IC has been described. It can be applied to general molding equipment.

[0067]

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

Since the runners are connected to each other by the connecting runners, the pressures of all the pots, culls, runners, gates, and resins in the cavities become uniform.
The injection pressure of the resin in each cavity is equal, and the molded product molded in each cavity can be molded with uniform quality.

Further, since the connecting runner for connecting the runners is arranged so as to be adjacent to the end face of the multiple lead frame, the connecting runner portion is formed at the end face of the multiple lead frame during molding. Therefore, it is possible to prevent the resin burr from being formed on the end surface of the multiple lead frame. Further, the connecting runner portion attached to the end face of the multiple lead frame can be easily removed from the multiple lead frame without forming a resin burr at the time of the gate break after molding.

[Brief description of drawings]

FIG. 1 is a plan view showing a lower mold of a transfer molding apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged partial front sectional view showing a main part of a transfer molding apparatus according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a tablet.

FIG. 4 is a plan view showing a resin-sealed object and a sectional view taken along line bb.

5A and 5B are a partially omitted partially cut enlarged plan view showing a state after resin sealing and a cross-sectional view taken along line bb.

FIG. 6 is a perspective view showing a molded body.

[Explanation of symbols]

1 ... Multiple lead frame, 2 ... Unit lead frame, 3
... outer frame, 4 ... section frame, 5 ... dam member, 6 ... dam,
7 ... Tab suspension lead, 8 ... Tab, 9 ... Lead, 9a ... Inner portion, 9b ... Outer portion, 11 ... Bonding layer, 12
... Pellet, 13 ... Wire, 14 ... Resin-sealed object (work), 15 ... Resin-sealed package, 20 ... Transfer molding device, 21 ... Upper mold, 22 ... Lower mold, 23 ... Cavity, 24 ... Pot, 25 ... Plunger, 26 ... Cal, 2
7 ... Runner, 27A ... Connection runner, 28 ... Gate, 29
... Lead frame escape recess, 31 ... Upper heat block, 32 ... Lower heat block, 33 ... Heater, 41 ...
Tablet, 42 ... Powdery resin (molding material), 43 ...
Liquefied resin (molding material), 100 ... Molded body, 126 ...
Cull part, 127 ... Runner part, 127A ... Connection runner part,
128 ... Gate section.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B29L 31:34 4F

Claims (3)

[Claims] 1. A plurality of pots into which tablets of the molding material are placed, heating means for heating the tablets placed in these pots to melt, and tablets which are inserted into the pots and crushed to form tablets. A plurality of plungers for pumping the molten molding material, a plurality of culls arranged so as to face each pot, and a plurality of claws fluidly connected to each cull. A molding apparatus comprising a runner and a plurality of cavities fluidly connected to each runner, wherein the plurality of runners are connected by a runner. apparatus. 2. The connection runner is arranged so as to be adjacent to an end surface of a multiple lead frame in which the semiconductor pellets and the leads, which are objects to be sealed with resin, are housed in the cavity. The molding apparatus according to claim 1. 3. In a molding apparatus comprising a plurality of pots and a plurality of cavities, each cavity being directly connected to the pot, a gate for injecting a molding material of each cavity is a connecting path. A molding device characterized in that they are fluidly connected to each other by.