JPS6235630A - Metal mold for molding encapsulated semiconductor device - Google Patents

Abstract

PURPOSE:To enable shortening delivery time and realizing standardization by attaching the top and bottom forces to the base boards as a unit structure each without making the ejector pins and a return pin penetrate the base boards. CONSTITUTION:Ejector pins 31 on upper cavities 30a and ejector pins 32 and a return pin 33 on the upper surface of a subrunner 1a are penetrated a top force 30 and the flange parts thereof are held by a press plate 34 just over the top force upper surface and an ejector plate 35. The press plate 34, the ejector plate 35 and a support pillar 40 are housed in the recessed part 37a of an upper base board 37 and the support pillar 40 prevents the top force 30 from being deformed due to mold clamping pressure. Moreover, both the runner block of the bottom force and the chamber block of the top force are respectively incorporated in the upper and lower base boards as a single unit each in the same structure as those of the bottom force unit and the top force unit. By this constitution, a shortening of delivery date and standardization can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mold used in molding a sealed semiconductor device.

[Conventional technology]

FIG. 7 is a plan view showing a conventional lower mold structure for molding a resin-sealed IC, and FIG. 8 is a sectional view taken along the line i--I in FIG.

In these figures, (1) is a runner block, and when the resin in the chamber of the upper mold is pressurized, a cull (1a) that branches the resin, a branch runner (1b), (
1c) is formed by processing. (2) is the lower mold, which includes a sub-runner (2a), a gate (2b) and a resin-sealed IC.
A large number of lower cavities (2c) having the same shape as the cylindrical shape are formed by processing. (3) is a positioning pin, which is attached to the lower mold (2) so that it fits into the positioning hole machined in the IC lead frame and allows the IC lead frame to be correctly positioned and mounted on the lower mold (2)K. (4) is a lower surface plate, to which a guide pin (5) for positioning with the upper surface plate is fitted and attached. (6) is a heater, and a plurality of heaters are inserted into the lower mold ff (4), and when energized, the temperature of the lower mold (2) is raised to the molding temperature. The launch block (1) and the lower die (2) are properly attached to the lower surface plate (4) with bolts and knock pins.

(The heat insulating plate is attached to the lower surface of the lower surface plate (4) and prevents the heat of the lower surface plate (4) from escaping to the slide table (8) of the press. (9) is the ejector plate,
a [ is the holding plate, aυ is the ejector pin of the cull (1a), a'a is the ejector pin of the lower cavity (2C), and each ejector pin flange (11a) and (12a) is the ejector plate (9) and the holding plate. It is mounted so as to pass through the lower surface plate (4) and the lower mold (2) and eject the cured resin within the cull (1a) and the lower cavity (2c). Ejector plate (9) and holding plate α
1 is a compression spring a3 installed between the lower surface plate (4) and the heat insulating plate (forced), and inserted between the lower surface plate (4) and the holding plate (11).
The insulation plate is always pushed back to the force side and is in contact with the insulation plate (7) when the mold is opened. The α shafts are support pillars, and there are multiple pillars between the lower surface plate (4) and the insulation plate (7). It is inserted to reduce the deflection of the lower surface plate (4) due to press pressure.

α9 uses bolts to attach the lower surface plate (4) to the press slide table (8). α0 is the base of the press, α force is a mold clamping cylinder, which is attached to the base aυ and raises and lowers the slide table (8) mainly by hydraulic pressure. α811/Tsukuoutrondo is attached to the base (1119), and its tip is attached to the slide table (8) and the heat insulating plate (7).
) and push up the ejector plate (9) near the bottom dead center of the press.Next, the structure of the upper mold will be explained with reference to Figures 9 and 10. Since they are similar, only the differences will be considered. Figure 10 is the 9th
FIG. 3 is a cross-sectional view taken along line I-I in the figure. (a) is the chamber block, with the lower mold cull (1a) K facing the chamber (2
1) is installed. (22) is an upper mold, in which an upper cabty (22a) having the same shape as the upper shape of the resin-sealed IC and an escape hole (22b) for the positioning pin (3) are machined. (23) is the upper surface plate, in which multiple heaters (24) are inserted like the lower mold surface plate (4), and the lower mold guide bin (5)
A guide bush (25) is attached so as to be slidably fitted with the guide bush (25).

(26) is the ejector play), (27) is the presser plate, (
28) are the branch runners (1b) and (1c) of the lower mold (2).
The ejector pin (29) on the upper surface of O is the upper cavity (2
2a) is the ejector pin. (60) is a return pin, which is attached in the same way as the ejector pins (28) and (29). Ejector pin (28), (2
9) The return pin (30) passes through the upper surface plate (23) similarly to the lower die. (31) is a heat insulating plate that prevents heat from the upper surface plate (23) from escaping to the press upper platen (32). (63) attaches the upper surface plate (23) to the upper platen (32) with bolts. Ejector plate (
26), the holding plate (27) is connected to the upper surface plate (23) and the heat insulating plate (
31), and is always pushed back toward the upper surface plate (26) by a compression spring (34), and when the mold is opened, the presser plate (2
7) and the upper surface plate (23) are in contact with each other.

(35) is a support pillar.

A conventional mold for molding a resin-sealed semiconductor device is constructed as described above, and a resin-sealed IC is molded using the above-described lower mold and upper mold. First, the lower mold and upper mold are heated by heaters (6) and (24) K, and the resin to be used,
For example, the temperature is raised to the molding temperature of epoxy resin or silicone resin, and the IC lead frame is set in the lower mold (2). The slide table (8
) is raised and the lower mold (2) and upper mold (22) are clamped. Just before mold clamping, the return pin (30) of the upper mold is attached to the lower mold (
2), lift the ejector plate (26) and remove the ejector pins (28) and (29) of the upper mold.
) to the position of 1N during molding.

Next, the preheated resin is loaded into the chamber (21), and the transfer plunger attached to the upper platen [
(not shown) is lowered into the chamber (21), the resin is melted by heat, and the cull (1a), branch lunch (1b)
, (1c), Subrunner (2a), Gate (2b)
, cavities (2c), and (22a) are injected and filled in this order. When the mold is opened after waiting for the resin to harden, the ejector pin (28) is released by the force of the compression spring (34) in the upper mold.
, (29) are activated to make the upper mold cavity (22a) and the branch runners (1b), (1c) m-shaped with the upper mold, so that the molded product descends together with the lower mold. When the temperature reaches near the bottom dead center, the knockout rod a8 moves the ejector plate (
9) is pushed upwards, ejecta pin υ, az
The molded product is separated from the lower mold. The molded product is taken out and one cycle of work is completed.

[Problem that the invention seeks to solve]

As mentioned above, in conventional molds for molding resin-sealed semiconductor devices, the ejector pin and return pin do not have a structure that allows them to move freely through the surface plate. If the pitch changes, it will be necessary to design and manufacture a new set of surface plates to match the pitch, which will hinder delivery times, etc.
To replace the ejector pin if it is damaged, it is necessary to remove the hot and heavy mold from the press and disassemble it for maintenance.It takes time to raise the temperature after it is placed on the press after maintenance, and it also increases production volume. There were various problems, such as the fact that it was almost impossible to switch models in a way that was appropriate for the current situation.

This invention was made to solve these problems, and can contribute to shortening delivery times and standardization, and facilitates maintenance.
A further object of the present invention is to obtain a mold for molding resin-sealed semiconductor devices that can simultaneously mold a plurality of models commensurate with the production volume.

[Means for solving problems]

The mold for molding a resin-sealed semiconductor device according to the present invention has a unit structure in which an ejector pin, an ejector plate, a presser plate, a compression spring, etc. are incorporated in the upper mold and the lower mold, respectively, and the ejector pin and return pin are fixed. The mold has a structure that does not penetrate the board.

[For production]

In this invention, the ejector pin, return pin, etc. do not pass through the surface plate, but are incorporated into the block, so that by replacing this block, the model can be changed or maintained.

〔Example〕

FIG. 1 is a plan view showing the lower mold structure of an embodiment of the present invention;
Figure 2 is like Figure 1! Fig. 6 is a sectional view taken along the -'1 line and the ■-n line. In these figures, (1) is a lower mold, in which a large number of sub-runners (1a), gates (1b), and lower cavities (1c) are formed. (2) is a positioning pin that is attached to the lower mold (1) and fits into the positioning hole of the IC lead frame to connect the IC lead frame to the lower mold (1).
), position and place it correctly. (3) is the lower cavity (
1c) is the ejecta pin, (4) is the subrunner (1a)
The flanges (3a) and (4a) of the ejector pin are held by a presser plate (5) and an ejector plate (6) located directly below the lower mold (1).

The holding plate (5) and ejector plate (6) are connected by bolts (
Fastened by force. Ejector pins (3) and (4) pass through the lower mold (1) and reach the cavity (1C) and subrunner (1a). (8) is a support pillar with a flange, and the narrow diameter part is the ejector plate (6) and the holding plate (5).
) and abuts the bottom of the lower die (1), and the bolt (9)
Installed by. 0IIS is a compression spring, and the lower mold (1
) and the holding plate (5), and the ejector plate (6) is always in contact with the flange of the flanged support pillar (8). The lower die (1) is attached to the lower surface plate α■ by bolt αD and dowel pin α2.

Figure 4 is a cross-sectional view showing the overall structure of the lower mold, in which the lower mold unit configured as a unit as described above is attached to the lower surface plate 0Q, and shows the presser plate (5) and ejector incorporated in the lower mold (1). The plate (6) has a recess (
13a). 0 is a guide pin at the bottom! The 0 (15) that is fitted and attached to H is a heater). By inserting multiple pieces into the lower surface plate α and energizing, the lower mold (1)
Raise the temperature to the molding temperature. αe is the ejector rod,
It penetrates the 6th floor of the lower surface plate and is arranged so that 2 to 4 ejector plates (6) per piece operate from a few positions before the bottom dead center of the press to push up the ejector plate (6) and eject the molded resin. ing. αη is a knockout plate stored at the bottom of the 6th floor of the lower surface plate, and the ejector rod α
υ is fixedly attached.

(18 is a heat insulating plate, and the lower surface plate (13 is attached to the bottom surface with bolts α9. The table (21) is fixed to the lower part 111 (1.
3) and the heat insulating plate OQ to prevent the lower surface plate from deflecting. (26) is a compression spring installed between the lower surface plate α■ and the knockout plate ση, and when the mold is opened, the knockout brake (17) is pushed back toward the heat insulating plate αgI side and brought into contact with it. (24) is the base of the press,
(25) is a mold clamping cylinder, which is attached to the base (24) and raises and lowers the slide table (20). (26) is a knockout rod, which is attached to the base (24), and its tip is attached to the slide table ('20). ) and insulation board 0
Ejector plate (6) passes through the barrel and is located at the bottom dead center of the press.
The length is such that the thrust is completed.

Next, the structure of the upper mold will be explained with reference to FIG. (60) is the upper mold, the upper cavity (30a) and the positioning bin (2)
A hole (30b) is machined. (31) is the ejector pin of the upper cavity (30a), (32) is the ejector pin on the upper surface of the u sub-runner (1a), and (33) is the return pin, each of which passes through the upper mold (30), and the flange is It is held by a presser plate (64) and an ejector plate (35) directly above the upper surface of the upper mold. The holding plate (34) and the ejector plate (35) are fastened together with bolts (66). (37) is an upper surface plate into which a plurality of heaters (68) are inserted and gasket bushes (39) are fitted and attached. The upper die (30) is attached to the upper surface plate (67) with bolts and seven pins. (40) is a support pillar, which passes through the ejector plate (35) and the holding plate (34), and is attached to the upper surface of the upper mold with a pole (41).

The holding plate (34), the ejector plate (35), and the support pillar (4o) are attached to the four parts (37a) of the upper surface plate (67).
), and the support pillar (40) prevents the Q upper mold (60) from deforming due to mold clamping pressure. (42) is a heat insulating plate, which is attached to the top surface of the upper surface plate (67) with a pole (43). The upper surface plate (67) is attached to the upper platen (45) of the press with a pole (44). (46) is a compression spring, (47) is a flanged knockout rod, which is attached as shown in the figure, and always presses the ejector plate (35) downward. It touches when the mold is opened.

Furthermore, the lower mold runner block has the same structure as the lower mold unit, and the upper mold chamber block has the same structure as the upper mold unit.
Each is incorporated into the upper and lower surface plates as individual units. Detailed explanation will be omitted.

FIG. 6 is a diagram showing a state in which the upper and lower molds according to the present invention are mounted on a press and clamped.
The unit is installed.

When the mold is clamped, the ejector plate (6) is pushed down by the compression spring αQ built into the lower mold (1), and the bottom surface of the ejector plate (6) is in contact with the lower surface plate (1■ concave! IS (13a) K in contact with the ejector pin (3), (4) is in the molded state position. Also, a compression spring (23) pushes down the lockout plate (L7) so that it comes into contact with the heat insulating plate mark a.

The return pin (33) of the upper mold is brought into contact with the lower mold (1) and the ejector pin (35) is pushed upward to set the ejector pins (31), (32) (r) in the mold state position. are doing. Upper mold compression spring (48
) is deflecting by the amount of return and is trying to push (35) back downwards with a stronger return play than in the set state.

During molding, the IC lead frame is set between the lower mold (1) and the upper mold (60), and in this state, preheated resin is loaded into the chamber and pressurized by the transfer plunger, the resin melts. Fill the cavity. Wait for the heat to harden and open the mold to release the compression spring (48).
As a result, the ejector pins (31) and (32) operate to eject the resin portion, so that the molded product descends together with the lower mold. Just before the bottom dead center of the press, the knockout rod (26) pushes up the knockout plate (17),
Also, when the knockout plate αD is pushed up, the ejector rod (1e is the ejector plate (6)
), the ejector pins (3) and (4) operate to release the molded product from the lower mold. After the mold release is completed,
When the molded product is taken out and the slide table (2G) is raised, the shejector plate (6) is moved by the compression spring α [to the knockout plate (1) by the compression spring (23).
7) returns to the original state, and j) becomes the state where the IC lead frame is set.

This completes one cycle.

In the above embodiment, the compression spring (1) and (26) were both incorporated to obtain the return force of the ejector pin of the lower die, but (23) was eliminated and only α1 was used. (17) may be restored by compressive force. Also, ejector plate (6) K T
Machining a groove and sliding the lower die (1,) so that the tip of the ejector rod αQ slides into the T groove,
Ejector plate (6) and ejector lorado (16)
Either of the compression springs may be omitted as long as they can be combined.

In addition, although the compression spring (48) of the upper die has been described as being assembled into the upper surface plate, the bolt that penetrates the ejector plate (65) and the holding plate (64) and is embedded in the upper die (60), A compression spring may be inserted into this bolt, and the compression spring may be tightened with a nut when the upper die (60) and the holding plate (64) come into contact with each other. The upper and lower molds are assembled as a unit without the return pins passing through the surface plate, so with the conventional structure, a new surface plate was designed and manufactured each time the molded product shape or cavity pitch changed. However, in the structure of the present invention, the surface plate is shared,
This can be done by manufacturing only the upper and lower molds, which has a great effect on shortening delivery times and standardizing. Further, even if the ejector pin is damaged, there is an advantage that it can be easily repaired by removing the unit. Furthermore, since it has a unit structure, it has the effect of being able to mold multiple models at the same time depending on the production volume.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a molding die for resin-sealed IC molding according to an embodiment of the present invention, and FIG. 2 is a plan view showing 1--
3 is a sectional view taken along the line II-'TI of the 1st part, FIG. 4 is a sectional view showing the overall structure of the lower mold, FIG. 5 is a sectional view of the upper mold structure, and 6th The figure is a cross-sectional view showing the state in which the upper and lower molds are clamped, Fig. 7 is a plan view showing the lower mold υ4 structure of a conventional resin-sealed IC molding die, and Fig. 8 is a cross-sectional view showing the state where the upper mold and lower mold are clamped. 9 is a plan view showing the upper mold structure, and FIG. 10 is a sectional view taken along line I--I in FIG. 9. In the figure, (1) is the lower die, (3) and (4) are the eject pins of the lower die, (5) is the holding plate, (6) is the ejector plate, (8) is the support pillar with flang, ([0) 03) is the lower surface plate, α is the guide bin, (151 is the heater, 00 is the ejector rod, α force is the knockout plate, α is the cutting i% plate, (21 is the slide table, (22) is the Support pillar, (26) is a compression spring, (
60) is the upper mold, (61), (32) u ejector pin, (33) is the return pin, (54) is the holding plate, (35)
) is the ejector plate, (37) i-11, upper surface plate,
(68) is the heater, (39) is the guide bush, (40)
is a support pillar, (42) is a heat insulating plate, (45) is an upper platen, (46) is a compression spring, (47) is a knock with a flange,
It is an out rod. In addition, the same reference numerals in each figure indicate the same or equivalent parts 0 Agent Patent attorney Masaru Sato 20 Subfu〉A2b Keto2c Lower Ki〒Goti Figure 9 A34! l IQ I! f 220 Nikiγbiti 22b ill hole

Claims (1)

[Claims] A lead frame on which a semiconductor device is assembled, an eject pin for positioning and mounting the lead frame, having a chamber, a pot, a runner, a gate, and a cavity for injecting resin into a portion of the semiconductor device, and ejecting the resin or the lead frame. In a pair of upper and lower molding molds having a return pin for returning the ejector pin, a spring for obtaining return force, and an ejector plate for holding the ejector pin and the return pin,
A resin-sealed mold for semiconductor molding, characterized in that the ejector pin and the return pin do not penetrate the surface plate, and the upper and lower molds are each attached to the surface plate as a unit structure.