JPH09181105A - Metal mold for sealing semiconductor resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal mold allowing to obtain products of an excellent property by improving efficiency of resin using together with preventing generation of quality deficiency. SOLUTION: In this metal mold, a lower mold 5, which is one side mold, is provided with a lower cavity 3 resin-sealing a semiconductor chip 9, a gate 1 for flowing molten resin into this lower cavity 3 and a cylindrical pot 2 for injecting resin is provided inside the range of a lead frame mounting part 4 for mounting a lead frame 8 mounting the semiconductor chip 9, however, referring to an upper mold 7, which is the other side type, only an upper cavity 6 is formed correspondingly to the lower cavity 3 of a lower mold 5, an upper cull, which is conventionally a flow path of molten resin formed corresponding to a pot 2 is excluded, provided here a gate 1 in the low mold 5 is provided by communication with the pot 2 so as to supply molten resin from the pot 2 to directly flow into the upper cavity 6 and the lower cavity 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a semiconductor resin encapsulating mold for resin encapsulating a semiconductor element to obtain a semiconductor package.

[0002]

2. Description of the Related Art Conventionally, as this type of resin-sealing mold, for example, there is a type whose schematic structure is shown in FIGS. However, FIG. 9 shows a partial plan view of a lower die main part in a conventional resin sealing die, and FIG. 10 shows a lead frame in which a semiconductor element is mounted on the lower die shown in FIG. It is a partial side sectional view including the upper mold in the state.

In this resin sealing mold, the lower die 5 is mounted on the lead frame mounting portion 4 and the lead frame 8 provided on the lead frame mounting portion 4 and electrically connected by the bonding wires 10. A lower cavity 3 for sealing the semiconductor element 9 with a resin, a runner 1 which plays a role of injecting the molten resin into the lower cavity 3 and an upper cavity 6 provided in the upper mold 7, and the resin is injected. And a cylindrical pot 2 for

On the other hand, as in the case of the lower cavity 3, the upper die 7 arranged to face the lower die 5 has an upper cavity 6 for resin-sealing the semiconductor element 9 and a role of flowing molten resin to the runner 1. And the upper cull 14 that bears the above.

With respect to the resin-sealing die having such a structure, each step of resin-sealing the semiconductor element 9 and taking it out of the die will be described with reference to FIGS. 11 to 13. To do.

In this mold, referring to FIG. 11, a resin tablet 12, which is a cylindrical tablet-shaped resin, is put into the pot 2 before the lead frame 8 is clamped, and serves to compress the resin tablet 12. It is held by the plunger 11. The resin tablet 12 is heated to a softened state suitable for resin sealing after the lead frame 8 on which the semiconductor element 9 is mounted is clamped by the upper mold 7 and the lower mold 5, and then the plunger 11 is raised. It is fluidized by the accompanying compressive force, passes through the runner 1 through the upper cull 14, and flows into the upper cavity 6 and the lower cavity 3.
Therefore, the state is maintained until the resin is cured and the resin filling is completed as shown in FIG. After the resin filling is completed, the upper mold 7 and the lower mold 5 are opened as shown in FIG. 13, and a mold composed of a resin molding runner 15 and a resin molding cull 16 is ejected from the mold by an ejector pin (not shown) provided on the upper mold 7 and the lower mold 5. The semiconductor package 13 including the outer resin molding portion is taken out.

Further, as another resin-sealing die, for example, a type whose schematic structure is shown in FIGS. 14 and 15 can be mentioned. However, FIG. 14 is a partial plan view of a lower die main part in another conventional resin sealing die, and FIG. 15 is a lead frame in which a semiconductor element is mounted on the lower die shown in FIG. It is a partial side cross-sectional view including the upper mold in a state where is set.

This resin sealing mold is
A bifurcated one is provided as the first runner 1a, and the lower die 5 includes a first lower cavity 3a and a second lower cavity 3a.
A second lower cavity 3b and a second lower cavity 3b which communicate with the first lower cavity 3a and the second lower cavity 3b.
Is provided with a runner 1b, and the upper mold 7 has a first upper cavity 6 corresponding to the first lower cavity 3a of the lower mold 5.
a and a second lower cavity 3b corresponding to the second lower cavity 3b.
And the upper cavity 6b is provided.

In this resin encapsulation mold, the steps until the semiconductor element 9 is resin-encapsulated and taken out from the mold are as described below.

First, before mold clamping, the resin tablet 12 put into the pot 2 is heated to a softened state which is sufficiently suitable for resin sealing, and then fluidized by the pressing force as the plunger 11 rises. , Passes through the first runner 1a via the upper cull 14, and flows into the first upper cavity 6a and the first lower cavity 3a. Further, the resin tablet 12 flows in as a molten resin from the first lower cavity 3a to the second lower cavity 3b via the second runner 1b. After the resin sealing is completed, the semiconductor package 13 is taken out from the mold by ejector pins (not shown) provided on the upper mold 7 and the lower mold 5 as shown in FIG.

Further, as another resin-sealing die, one related to the resin molding apparatus for electronic parts disclosed in Japanese Patent Laid-Open No. 4-246516 can be mentioned. The feature of the mold is that it excludes the culls and runners that are the flow paths for the molten resin from the mold.

As shown in FIG. 17, this resin-sealing die is constructed such that the upper die 7 can be clamped and opened with respect to the lower die 5, and the upper die 7 has an upper portion. A base 18 and a resin injection pin 17 fixedly held by the base 18 are arranged so as to be movable up and down relatively to the upper mold 7.

In this resin encapsulation mold, a lead frame on which a semiconductor element is mounted is installed at a predetermined position on the lower mold 5, and the upper mold 7 is lowered to allow the upper and lower molds 5 and 5 to be connected. Clamp. At this time, the base 18 and the resin injection pin 17 do not exist above the upper mold 7.

After the lead frame is clamped by the upper mold 7 and the lower mold 5, the resin tablet is charged into the resin tablet holding hole 19 in the lower mold 7 by another mechanism (not shown) for charging the resin tablet. After loading the resin tablet, the separate mechanism for loading the resin tablet moves from the upper part of the upper mold 7 to another stage (not shown). Instead, the base 18 and the resin injection pin 17 held by the base 18 move to the upper part of the upper mold 7 and stop after descending to a predetermined proper position. Base 1
8 and the resin injection pin 17 are lowered, the resin tablet in the resin tablet holding hole 19 is compressed, flows into the upper cavity 6 and the lower cavity 3 and is filled, so that the tightened state shown in the drawing is obtained.

[0015]

In the case of the resin encapsulating mold according to the above-mentioned example, the semiconductor package molded after the resin encapsulation includes the resin molded runner formed in the runner, the upper mold and the pot. The molded resin molding cull is attached as an out-of-mold resin molded portion, but such an out-of-mold resin molded portion is removed as an unnecessary portion when a semiconductor package product is obtained.

Therefore, the ratio of the resin used in the semiconductor package product to the total amount of the resin used (hereinafter referred to as resin use efficiency) is relatively low, and generally depends on the size of the semiconductor package 13. But on average 50-60
It is about [%], and there is a drawback that the resin use efficiency is not good.

Further, in the case of the resin sealing die according to another example, the resin use efficiency is not good at 50 to 60% as in the case of the resin sealing die according to the previous example. In addition to the above, there is another problem that deteriorates product quality.

For example, FIG. 21 shows the torque Tr [Kg for a general thermosetting resin heated at a specific temperature.
f · cm] is a resin curing curve showing the characteristic of curing that appears when the [f.

Here, at time t2, the minimum torque a [kg
f · cm], indicating that the resin is in the most molten state at this time t2. Therefore, it is desirable that the time from the start of the resin sealing to the end of the resin sealing is around this time t2. However, strictly speaking, the torque of the resin suitable for resin sealing is obtained by an evaluation experiment, but here, the torque b [kgf · cm] or less corresponding to the times t1 and t3 (t3> t1) is desired. It is in a resin state.

That is, in the heating time t of the resin, a suitable sealing condition is to start and end the resin sealing from the time t1 to the time t3. On the other hand, for example, the torque c [kgf · cm] at time t4 is in the state of exceeding the torque value b [kgf · cm], which indicates the state where the curing of the resin has progressed. If the resin sealing is not completed at this time t4, voids that adversely affect the product quality,
Problems such as unfilling and wire short-circuiting occur.

As a result, in the case of the resin sealing mold according to another example, the first upper cavity and the lower cavity are followed by the second cavity.
Since the molten resin flows into the upper and lower cavities, even if the molten resin flows into the first upper and lower cavities from time t1 to time t3 described in FIG. 21, If the resin sealing is not completed in the second upper cavity and the lower cavity for more than the time t3, the semiconductor package molded in the second upper cavity and the lower cavity has voids, non-filling, wire shorts, etc. There is a problem that product defects occur. Further, if the inflow speed of the molten resin is increased in order to complete the resin sealing of the second upper cavity and the lower cavity between the time t1 and the time t3, a wire short circuit occurs, resulting in a defective product. There is also the problem of being lost.

Further, in the case of a mold for resin encapsulation according to another example in which culls and runners are eliminated in order to improve the resin use efficiency,
The elimination of these causes a contradictory problem.

Specifically, as shown in FIG. 18, since the resin injection portion is above the lead frame 8, the lead frame 8 and the bonding wire 10 are deformed downward due to the flow-in of the resin. . In these cases,
The bonding wire 1 is deformed by the deformation of the lead frame 8.
When 0 and the semiconductor element 9 contact each other, a product defect occurs, and when the bonding wires 10 contact each other, a wire short occurs, causing a product defect. In addition, if the weight of the resin tablets used is uneven, the inflow resin 20 may be unfilled, and conversely, an extra protrusion may be formed at the resin injection port on the product surface. There are also problems that arise.

FIG. 19 shows a state of the unfilled portion 21 that occurs when the weight of the resin tablet used is small with respect to the required resin amount, and FIG. 20 is the resin tablet used with respect to the required resin amount. 3 shows a state of the protruding portion 22 that occurs when the weight of the item varies.

The present invention has been made to solve the above problems, and its technical problem is to improve the efficiency of resin use and prevent defects such as unfilling, voids, and wire shorts. It is to provide a mold for semiconductor resin encapsulation that can obtain a product of excellent quality.

[0026]

According to the present invention, the mold is composed of two molds that are openably and closably opposed to each other, and one mold has a cavity for resin-sealing a semiconductor element, and a molten resin flows into the cavity. A runner and a cylindrical pot for introducing resin are provided, and the other mold has a cavity formed corresponding to the cavity of one mold and the melting formed corresponding to the pot of one mold. In the mold for semiconductor resin encapsulation provided with cull which is a resin flow path,
A mold for semiconductor resin encapsulation is obtained in which one mold is provided with a runner in communication with the pot and the other mold is free of cull.

Further, according to the present invention, in the above-mentioned semiconductor resin encapsulating mold, the pot and the runner are the semiconductor resin encapsulating mold formed within the mounting range of the lead frame on which the semiconductor element is mounted. To be

Furthermore, according to the present invention, in any one of the above-mentioned molds for encapsulating a semiconductor resin, a plurality of cavities of one mold and a plurality of cavities of the other mold are provided, and one runner is used as a pot and one is used as a pot. A mold for semiconductor resin encapsulation is provided which is provided in a plurality so as to communicate with a plurality of cavities in the mold and is formed so that the molten resin has the same flow rate.

In addition, according to the present invention, in the above-mentioned semiconductor resin sealing mold, a plurality of runners can be obtained which have the same cross-sectional shape and area and the same length dimension. .

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The semiconductor resin encapsulating mold of the present invention will be described in detail below with reference to the accompanying drawings with reference to some examples. [Embodiment 1] FIGS. 1 and 2 show a schematic structure of a resin encapsulating mold according to Embodiment 1 of the present invention. However,
FIG. 1 is a partial plan view of a lower die main part in a resin sealing die, and FIG. 2 shows a state in which a lead frame having a semiconductor element mounted on the lower die shown in FIG. 1 is set. It is a partial side sectional view including an upper mold.

This resin encapsulation mold is also composed of two upper and lower molds 7 and 5, which are arranged to face each other so as to be openable and closable, and one of the lower molds 5 is resin-sealed with the semiconductor element 9. The lower cavity 3, the runner 1 for flowing the molten resin into the lower cavity 3, and the cylindrical pot 2 for charging the tablet-shaped or granular resin to mount the lead frame 8 on which the semiconductor element 9 is mounted. Although it is provided within the range of the lead frame mounting portion 4 of the above, only the upper cavity 6 is formed corresponding to the lower cavity 3 of the lower die 5 with respect to the upper die 7 which is the other die. Cull, which is a correspondingly formed molten resin channel, is eliminated.

However, here, the runner 1 in the lower die 5 is used.
Is provided so as to communicate with the pot 2, and the molten resin supplied from the pot 2 directly flows into the upper cavity 6 and the lower cavity 3.

With respect to the resin-sealing die having such a structure, the semiconductor element 9 is resin-sealed and the respective steps until the semiconductor element 9 is taken out from the die in that state will be described with reference to FIGS. explain.

In this mold, referring to FIG. 3, the resin tablet 12 put in the pot 2 is replaced by the plunger 11.
It is held in the pot 2 by means of preheated to a softened state suitable for resin sealing, then fluidized by the compressive force associated with the rise of the plunger 11, and the upper cavity 6 via the runner 1 in direct communication with the pot 2. And flows into the lower cavity 3. However, regarding the method of charging the resin tablet 12 into the pot 2, the resin tablet 12 is previously charged into the pot 2 before the lead frame 8 is set on the lower mold 5 with the upper mold 7 and the lower mold 5 opened. Alternatively, after the lead frame 8 is set on the lower mold 5 using the lead frame 8 (not shown) that has been subjected to the hole processing for resin tablet insertion, the hole for resin tablet insertion of the lead frame 8 is formed. The resin tablet 12 may be put into the pot 2 via the.

Therefore, the state is maintained until the resin is softened and the resin filling is completed as shown in FIG. After the resin filling is completed, as shown in FIG. 5, the upper mold 7 and the lower mold 5
The mold is opened, and the semiconductor package 13 having a small out-of-mold resin molding portion is taken out from the mold by ejector pins (not shown) provided on the mold.

If this resin encapsulation mold is used, the extra out-of-mold resin molding portion of the resin-cured semiconductor package 13 is extremely small, so that the average is 50 to 60 [%] in the past. Average resin usage is 80-9
Improves to 0%. Further, in the case of this resin sealing mold, since the molten resin is smoothly supplied from the pot 2 into the upper cavity 6 and the lower cavity 3 from the side wall direction of the lower cavity 3, the resin flow-in is performed. As a result, the lead frame 8 and the bonding wire 10 are less likely to be deformed, defects due to unfilling, voids, wire shorts, etc. are prevented, and the semiconductor package 13 is obtained with excellent quality. [Embodiment 2] FIG. 6 and FIG. 7 show a schematic structure of a resin sealing mold according to Embodiment 2 of the present invention. However,
FIG. 6 is a partial plan view of a lower die main part of a resin sealing die, and FIG. 7 shows a state in which a lead frame having a semiconductor element mounted on the lower die shown in FIG. 6 is set. It is a partial side sectional view including an upper mold.

In comparison with the resin mold of the first embodiment, this resin molding die is provided with a plurality of lower cavities 3 of the lower die 5 and upper cavities 6 of the upper die 7 (four in this case), and A plurality of (four in this case) runners 1 are provided to communicate the pot 2 with each lower cavity 3 of the lower die 5 and one point of the die 5 for resin sealing. In addition, it is different in that the molten resin is formed to have an equal flow rate.

Here, each runner 1 has the same cross-sectional shape and area, and the same length dimension.
That is, in FIG. 6, the distance from the center of the pot 2 to the resin inlet of each lower cavity 3 is equal.

Also in this resin-sealing die, the steps until the semiconductor element 9 is resin-sealed and taken out from the die in this state are the same as those in the first embodiment.
After completion of the resin filling, the four semiconductor packages 13 integrated by sharing the small out-of-mold resin molding portion are taken out from the mold as shown in FIG.

Also in the case of this resin encapsulation mold, since the out-of-mold resin molding portion of each semiconductor package 13 is extremely small, the resin use efficiency is improved as in the case of Embodiment 1, and the molten resin Is smoothly supplied from the side wall of each lower cavity 3, the lead frame 8 and the bonding wire 10 are not easily deformed by the resin flow input, and defects such as unfilling, voids, and wire shorts occur. Semiconductor package 1
3 is obtained with excellent quality.

In the second embodiment, the structure for obtaining the four semiconductor packages 13 has been described, but the same effect can be obtained even with a structure for obtaining a plurality of semiconductor packages 13 other than this.

[0042]

As described above, according to the present invention, the conventional resin sealing mold composed of one mold and the other mold is improved, and the other mold is provided with a resin flow path. In addition to eliminating the void, the runner that flows the molten resin into the cavity for resin sealing is directly connected to the pot that puts the resin in one mold, and the lead frame of one mold is used for the lead frame on which the semiconductor element is mounted. Since they are located within the mounting area and the molten resin is smoothly supplied from the pot into the cavity from the side wall of the cavity of one mold, the resin molding part outside the mold becomes extremely small and resin is used. The efficiency is remarkably improved, and the lead frame and the bonding wire are not deformed by the resin flow input, so that there is no filling, void, or wire short circuit. Generation is prevented, so that a semiconductor package is obtained in excellent quality. Also, in a resin sealing mold for obtaining a plurality of semiconductor packages,
Since a plurality of cavities are provided in one mold and the other mold and the cavities of the one mold and the pot are connected by a plurality of runners, the same effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial plan view showing a main part of a lower mold in a resin sealing mold according to a first embodiment of the present invention.

FIG. 2 is a partial side cross-sectional view including an upper mold in a state where a lead frame having a semiconductor element mounted thereon is set in the lower mold shown in FIG.

FIG. 3 is a partial side sectional view showing a state before resin sealing after the lead frame is clamped in the resin sealing mold according to the first embodiment described with reference to FIGS. 1 and 2.

FIG. 4 is a partial side cross-sectional view showing a resin filling completed state in the resin sealing die according to the first embodiment described with reference to FIGS. 1 and 2.

FIG. 5 is a partial side cross-sectional view showing a state in which a product is taken out after completion of resin sealing in the resin sealing die according to the first embodiment described with reference to FIGS. 1 and 2.

FIG. 6 is a partial plan view showing a main part of a lower mold of a resin sealing mold according to a second embodiment of the present invention.

FIG. 7 is a partial side cross-sectional view including an upper mold in a state where a lead frame having a semiconductor element mounted on the lower mold described in FIG. 6 is set.

8 is a partial side cross-sectional view showing a state where a product is taken out after completion of resin sealing in the resin sealing die according to the second embodiment including the lower die described in FIG.

FIG. 9 is a partial plan view showing an essential part of a lower mold in a resin sealing mold according to a conventional example.

10 is a partial side cross-sectional view including an upper mold in a state where a lead frame having a semiconductor element mounted thereon is set in the lower mold shown in FIG.

FIG. 11 is a partial side cross-sectional view showing a state before resin sealing after the lead frame is clamped in the resin sealing mold according to the conventional example described in FIGS. 9 and 10.

FIG. 12 is a partial side sectional view showing a resin filling completed state in the resin sealing die according to the conventional example described in FIGS. 9 and 10.

FIG. 13 is a partial side cross-sectional view showing a state in which a product is taken out after completion of resin sealing in the resin sealing die according to the conventional example described with reference to FIGS. 9 and 10.

FIG. 14 is a partial plan view showing a lower die main part of a resin sealing die according to another conventional example.

15 is a partial side cross-sectional view including the upper mold in a state where the lead frame having the semiconductor element mounted thereon is set in the lower mold shown in FIG.

FIG. 16 is a partial side cross-sectional view showing a product taking-out state after completion of resin sealing in the resin sealing die according to another example of the related art described in FIGS. 15 and 15.

FIG. 17 is a partial side cross-sectional view showing a resin filling completion state in a resin sealing die according to another conventional example.

FIG. 18 is a partial side cross-sectional view shown for explaining a problem associated with resin filling in a resin sealing die according to another conventional example.

FIG. 19 is a partial side cross-sectional view shown for explaining another problem associated with resin filling in a resin sealing die according to another conventional example.

FIG. 20 is a partial side cross-sectional view shown for explaining another problem associated with resin filling in a resin sealing mold according to another conventional example.

FIG. 21 is a resin curing curve showing the characteristic of curing that appears when a torque test is performed on a thermosetting resin heated at a specific temperature in relation to the heating time.

[Explanation of symbols]

 1, 1a, 1b Runner 2 Pot 3, 3a, 3b Lower cavity 4 Lead frame mounting part 5 Lower mold 6, 6a, 6b Upper cavity 7 Upper mold 8 Lead frame 9 Semiconductor element 10 Bonding wire 11 Plunger 12 Resin tablet 13 Semiconductor Package 14 Upper cull 15 Resin molding runner 16 Resin molding cull 17 Resin injection pin 18 Base 19 Resin tablet holding hole 20 Inflow resin 21 Unfilled part 22 Projected part

Claims (4)

[Claims] 1. A cavity for sealing a semiconductor element with a resin, a runner for flowing a molten resin into the cavity, and a cylinder for injecting the resin, the cavity being composed of two molds that are openably and closably opposed to each other. A pot of shape is provided,
The other mold is a semiconductor resin seal provided with a cavity formed corresponding to the cavity of the one mold, and a cull which is a flow path of molten resin formed corresponding to the pot of the one mold. A die for semiconductor resin encapsulation, wherein the runner is provided in the one die in communication with the pot, and the cull is excluded from the other die. 2. The semiconductor resin encapsulating mold according to claim 1, wherein the pot and the runner are formed within a mounting range of a lead frame on which the semiconductor element is mounted. Stopping mold. 3. The semiconductor resin encapsulating mold according to claim 1, wherein a plurality of cavities of the one mold and a plurality of cavities of the other mold are provided, and the runner is one as the pot. A semiconductor resin encapsulating mold, wherein a plurality of cavities in one mold are provided so as to communicate with the plurality of cavities and are formed so that the molten resin has an equal flow rate. 4. The mold for semiconductor resin encapsulation according to claim 3, wherein each of the plurality of runners has the same cross-sectional shape and area and the same length dimension. .