JPH036410Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a transfer molding mold for molding packages of semiconductor products such as IC elements and transistors.

"Prior Art" Generally, this type of transfer molding mold is molded at a mold temperature of 170 to 180° C. depending on the characteristics of the resin (thermosetting resin) used. Therefore, the mold has a structure that incorporates a heating device and insulation material, and the resin used has extremely high fluidity, and the viscosity of the injection molding resin (thermoplastic resin)
Its viscosity is 250 to 300 poise, which is about 1/10 or less compared to 3000 poise.

Incidentally, in recent years, there has been a tendency for transfer molding molds such as those described above to have a large number of molds and to become larger in size. Furthermore, as the degree of integration of IC elements increases year by year, the elements themselves are becoming thinner and more fragile, requiring low-pressure molding, and as a result, more fluid resins are being used.

``Problems that the invention aims to solve'' However, when using highly fluid resins like this, there are problems such as variations in processing dimensions in the thickness direction of upper and lower cheeses with cavities formed on the mating surfaces, and heat distribution. Resin tends to leak from the cavity due to changes in mold thickness due to defects or variations in the thickness of the inserted lead frame, and as shown in FIG. There is a problem in that so-called flash 3 occurs, in which the resin adheres in the form of burrs.

Conventionally, in order to prevent the occurrence of burrs, the cavity insert 5 on which the cavity 4 is formed is inserted into the chase 6, and the cavity insert 5 of the An elastic member 7 is attached to the opposite side of the insert, or a spring (or disc spring) 8 is interposed between the cavity insert 5 and the chase 6 as shown in Fig. 5. Alternatively, as shown in FIG. 6, the chain 9 is curved to provide a spring effect. However, in the case where the elastic member 7 is attached to the chain 6 shown in FIG. 4, there is a problem that the effect is small because the position of the elastic member 7 is far from the cavity insert 5. Furthermore, in the case where a spring (disc spring) 8 is interposed between the cavity insert 5 and the chase 6 shown in FIG. 5, it is effective at the beginning of the interposition, but
The problem is that it has a short lifespan and quickly loses its effectiveness. Furthermore, if the chain 9 shown in FIG. 6 itself has a spring effect, there is a problem that it is difficult to process and the manufacturing cost increases.

This invention was made in view of the above circumstances,
The purpose of this is to prevent burrs from forming on the molded product even if the resin used is highly fluid, to make it possible to mold a molded product of good quality, and to have a simple structure. The purpose of the present invention is to provide a mold for transfer molding that is easy to manufacture and has a long-lasting effect.

"Means for Solving the Problems" In order to achieve the above object, the present invention involves fitting a pair of cavity inserts each having a cavity formed on their mating surfaces into a cheese, and fitting the cavity insert and the cheese into a pair of cavity inserts. In addition to forming a recess for inserting an insert component, an elastic member is attached to the back side of the cavity insert by protruding from the chase with a fixing bolt, and a template is attached to the chase.

"Operation" In the transfer molding mold of the present invention, the elastic material placed on the back side of the cavity insert protruding from the cheese is pressed by the template attached to the cheese. The elastic material firmly presses the cavity inserts together,
By forming a cavity and firmly and reliably holding the part of the insert parts inserted into the recesses formed in the cavity insert and the cheese between the cavity inserts, the machining dimensions of the cheese can be improved. variation,
Absorbs changes in mold thickness due to poor heat distribution, variations in the thickness of the inserted lead frame, etc., and prevents the resin in the cavity from flowing out along the insert parts and preventing it from becoming burrs and sticking. .

"Embodiment" Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 and 2.

Reference numeral 10 in the figure is an upper mounting plate, and an upper mold plate 13 is fixed to the lower surface of this upper mounting plate 10 via an upper spacer 11 and an upper heat insulating plate 12. Then, on the lower surface of this upper mold plate 13, an upper cheese 1 is provided.
4 is fixed, and an upper cabinet insert 15 is fitted into the lower part of this upper chase 14. A recess (upper cavity) 16 is formed at a predetermined location on the lower surface of the upper cavity insert 15. Further, on the upper surface (back surface) of the upper cavity insert 15, an elastic material 17 is attached to the upper cavity with a fixing bolt 18 with the upper surface slightly (for example, about 0.01 to 0.02 mm) protruding from the upper chain 14. It is attached to the vinyl insert 15.

An upper protruding plate 19 and an upper protruding plate retainer 20 are provided between the upper mounting plate 10 and the upper mold plate 13 so as to be movable up and down while holding the collar of the upper protruding pin 21. . And these upper protruding plates 19
The upper protruding pin 21 penetrates the upper die plate 13 and the upper chase 14 and protrudes and retracts into the upper cavity 16 by means of the upper protruding plate retainer 20. Further, a spring 22 is provided for causing the upper protruding pin 21 to protrude into the upper cavity 16 when the mold is opened.
is arranged on the upper surface of the upper protruding plate 19.

Below the upper mounting plate 10, the upper mounting plate 10
A lower mounting plate 23 is provided facing the lower mounting plate 23, and the mounting plates 10 and 23 come close to each other during mold clamping.
They are designed to be separated when the mold is opened. Then, on the upper surface of this lower mounting plate 23, a lower spacer 24,
Lower template 2 via support 25 and lower insulation material 26
7 are arranged. Further, a lower chase 28 is fixed to the upper surface of the lower mold plate 27, and a lower cavity insert 29 is attached to the upper part of the lower chase 28.
is embedded. This lower cabinet insert 2
9 and the upper surface of the lower chase 28, there is a recess (lower cavity) 30 and a lead frame (insert part).
31 insertion recesses 32 are formed at predetermined locations, and gates 33 and runners 34 communicating with the lower cavity 30 are formed, respectively. And the above upper and lower cavities 16,30
A cavity for a package of a semiconductor product is formed by this. Further, on the lower surface (back surface) of the lower cavity insert 29, an elastic material 35 is attached to the lower cavity with a fixing bolt 36 with the lower surface slightly (for example, 0.01 to 0.02 mm) protruding from the lower chase 28. It is attached to the insert 29.

Further, between the lower mounting plate 23 and the lower mold plate 27, a lower protruding plate 37 and a lower protruding plate retainer 38 are installed along the support 25 while holding the collar of the lower protruding pin 39. It is movable up and down. By means of the lower protruding plate 37 and the lower protruding plate retainer 38, the lower protruding pin 39 penetrates the lower die plate 27 and the lower chase 28 and comes to protrude and retract into the lower cavity 30. There is. moreover,
A spring 40 is installed between the lower protruding plate 37 and the lower mold plate 27 to urge the lower protruding plate 37 downward, and a stopper 4 is mounted on the lower surface of the lower protruding plate 37.
1 is installed.

In the transfer molding mold configured as described above, as shown in FIG. Chase 1
After the mating surfaces 4 and 28 are packed together, resin is supplied into the cavity through the runner 34 and gate 33 as in the conventional method, and a plastic package of the semiconductor product is molded. In this case, the upper and lower chases 14, 28 are attached to the back side of the upper and lower cavity inserters 15, 29 forming the upper and lower cavities 16, 30.
Since the elastic members 17 and 35 are installed so as to protrude vertically from the
Even if there are variations in the processing dimensions in the thickness direction of the elastic materials 1 and 28, changes in mold thickness due to poor heat distribution, or variations in the thickness of the lead frame 31 to be inserted, these
7, 35, the lead frame 3
1 is sufficiently pressed by the upper and lower chases 14 and 28. Therefore, the resin does not leak to the outside along the lead frame 31, so-called flashing can be prevented, and a product of good quality can be molded.

"Effects of the Invention" As explained above, according to the invention, a pair of cavity inserts each having a cavity formed on their mating surfaces are fitted into each cheese, and the cavity insert and the cheese are provided with a hole for inserting an insert component. In addition to forming a recess, an elastic material is attached to the back side of the cavity insert by protruding from the cheese using a fixing bolt, and a template is attached to the cheese. An elastic material placed on the side protruding from the cheese is pressed by a template attached to the cheese, and this elastic material strongly presses the cavity inserts together to form a cavity and By firmly and reliably holding the parts of the insert parts inserted into the recesses formed in the cavity insert and the cavity between the cavity inserts, it is possible to prevent variations in machining dimensions of the chain and poor heat distribution. Changes in mold thickness and variations in the thickness of the inserted lead frame can be smoothly absorbed, and the resin in the cavity does not flow out along the insert parts, preventing them from becoming burrs and sticking. This method has excellent effects such as being able to reliably prevent the problem, being able to mold products of good quality, having a simple structure and being easy to manufacture, and maintaining the effect for a long period of time.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention, with Figure 1 being a cross-sectional view of the main parts of the mold, Figure 2 being a schematic cross-sectional view with some parts omitted, and Figure 3 being a flat part. 4 to 6 show conventional transfer molding molds. FIG. 4 is a sectional view of an example using an elastic material, and FIG. Cross-sectional view of an example used, No. 6
The figure is a sectional view of an example of a curved chain. 13...Upper template, 14...Upper chase, 15...
...Upper cabinet insert, 16...Recess (upper cabinet), 17...Elastic material, 18...Fixing bolt, 2
7...Lower template, 28...Lower cheese, 29...Lower cavity insert, 30...Recess (lower cavity),
31...Lead frame (insert part), 3
2... recess, 35... elastic material, 36... fixing bolt.

Claims (1)

[Scope of utility model registration request] A pair of cavity inserts each having a cavity formed on their mating surfaces are fitted into the respective cheeses, and a recess for inserting the insert component is formed in the cavity insert and the cheese, and with the above-mentioned respective cheeses together, the above-mentioned In a transfer molding mold for molding by supplying resin into a cavity, an elastic material is attached to the back side of the cavity insert by a fixing bolt so as to protrude from the chain;
A mold for transfer molding, characterized in that a template is attached to the above-mentioned cheese.