JPH1158454A - Thermosetting resin molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of void, due to rolling of air, or the lack of resin, due to unloaded resin, and permit stabilized molding suitable for the sealing of resin through low-pressure molding by a method wherein the flow passage of resin is structured so as to be communicated with a runner unit through a resin reservoir from a pot unit. SOLUTION: The flow passage of molten resin is formed of a pot unit 2a, provided on a bottom force 2, and a gap 3, formed of the end face of the tip end unit 2b of the pot, which is formed of the parting surface of the bottom force 2 so as to have a projected configuration, and the bottom surface of a recessed part 1a, which is provided on a top force 1 and whose outer periphery is overlapped with a runner unit 5. Further, the flow passage of molten resin is formed in the sequence of a resin reservoir 4, provided on the side of the top force 1 so as to be surrounded by the inner peripheral surface of the recessed part 1a of the top force 1 and the runner unit 5, communicated with the resin reservoir 4. The flow passage of resin is structured so as to be communicated with the runner unit 5 from the pot unit 2a through the resin reservoir 4 in such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin molding die, and more particularly to a resin molding of a semiconductor or the like by low-pressure molding, which does not cause voids due to entrainment of air and chipping due to unfilling during molding. The present invention relates to a thermosetting resin molding die capable of performing suitable stable molding.

[0002]

2. Description of the Related Art Due to recent miniaturization of electronic equipment, the density of semiconductor components has been increased, the degree of integration of circuit components has been increased, and the demand for improved reliability of each component has become strict. Along with this, low pressure sealing of electronic components such as semiconductors with a thermosetting resin is generally performed by a transfer molding method. This method is performed as follows using the curing characteristics of the resin used.

The prior art will be described below with reference to the drawings. FIG. 6 is a plan view of a main part of a lower mold showing a resin flow channel structure of a single-pot type thermosetting resin molding mold having one pot in one general mold, and FIG. FIG. 4 shows a diagram of a curing characteristic of a resin in a molding step using a resin molding die. In FIG. 6, reference numeral 51 denotes a cull portion in which a solidified resin remains after a plunger (not shown) in the pot is actuated and molten resin is pumped, and 52 denotes a cull portion in which the flowing resin flows.
A runner section, which is a flow path when branching and flowing from 1, 5
3 is a gate, and 54 is a cavity into which resin is injected from the gate 53.

In FIG. 7, at c, a resin tablet is put into a pot of a high-temperature mold. At d, a lead frame is set after c and the lower mold is raised, and the upper mold and the lower mold are closed and clamped. I do. The resin starts to melt at e, raises the plunger at f, starts thickening the resin at g, and stops the plunger at h. i is a gel point at which the resin cannot flow, and j is a mold that is opened by opening the upper mold and the lower mold to take out a solidified molded product. a
Indicates the gelation time from the start of heating to the gelling point i at which the tablet-shaped resin put into the pot softens from the start of heating and becomes non-flowable, and b indicates the optimum viscosity range in which the viscosity of the resin becomes the lowest. Is shown.

[0005] A transfer molding process using a conventional single pot type will be described with reference to Figs. A resin tablet is put into a heated lower mold pot of a thermosetting resin molding die (hereinafter referred to as a molding die) (c), and then a lead frame on which components are mounted is set, and the lower die and the upper die are set. Align the mold, close the mold and close the mold (d),
Further, the operation of the plunger is started according to the setting conditions of the molding machine at the stage (e) at which the resin starts to melt in the sealed pot (f). The molten resin pumped by the plunger flows through the runner section 52 and reaches the gate 53. At this time, the viscosity of the resin becomes the optimum viscosity range (b) in the lowest state, the resin passes through the gate 53, fills the cavity 54, and the operation of the plunger stops (h). In the process of filling the cavity 54, the resin starts to thicken (g), and the molded product starts to solidify from the gel point (i) where the resin cannot flow. The molding die is opened at the point (j) at which the molded product is hardly deformed, and the molded product is taken out to complete the molding process.

Various techniques have been disclosed for the purpose of improving the above-mentioned conventional techniques. In the resin sealing device described in Japanese Utility Model Publication No. 3-45781, in a single pot type molding die, a dummy cavity into which resin is injected from a gate of a runner branched first from a main runner branched from a cull portion is formed. Also, there is disclosed a technique for concentrating the occurrence of molding defects.

FIG. 8 is a plan view of a main portion showing a resin flow path of a resin sealing mold for a multi-plunger described in Japanese Patent Application Laid-Open No. 63-72516. In the figure, 71 is a cull portion, 72 is a runner portion, 73 is a gate, and 74 is a cavity. Cavities 74 on the left and right of the cull (pot) 71
The runner 72 branching right from the cull portion 71 bypasses the cull portion 71 and the gate 7 of the cavity 74 on the left side.
It communicates with 3. Similarly, a runner part 72 branched to the left from the cull part 71 bypasses the cull part 71 and communicates with the gate 73 of the cavity 74 on the right side. With this structure, low-viscosity resin completely melted by receiving heat from a high-temperature molding die while the resin flows through the long runner portion 72 of the flow path passes through the gate 73 and fills the cavity 74.

As another conventional technique, Japanese Utility Model 3-40
In the resin sealing mold described in Japanese Patent Application Publication No. 579, a plurality of pots of a multi-pot type molding die are communicated with each other by a runner so that a plurality of pots are pressure-fed by a plurality of plungers. There is disclosed a technique for adjusting the pressure transmitted to the applied resin in the same manner.

FIG. 5 is a sectional view of a main part of a conventional multi-pot type molding die. In the figure, 21 is an upper mold, 22 is a lower mold, 26 is an upper cavity provided in the upper mold 21, 27 is a lower cavity provided in the lower mold 22, and 11 is a plunger for feeding molten resin by pressure. , 12 is a resin tablet before melting, 22a is a resin tablet 12
, A pot portion where the remainder of the resin pumped by the plunger solidifies, a runner portion 24 which is a resin flow path from the cull portion 21a to the gate, and 25 a resin for filling the cavities 26 and 27. Gate 13 as an entrance, 13 is a lead frame on which electronic components are mounted and loaded into a lower mold, 8 is a temperature control hole into which a heater is inserted, 9 is an ejector pin that projects a molded product, and 10 is an ejector that projects a runner and a gate. Pins are shown.

[0010]
Resin sealing using the above-described molding die is performed as follows. After the molding die is heated to a predetermined molding temperature by heating the temperature-adjusted heater inserted into the temperature-adjusting hole 8 of the clamped molding die, the molding die is opened and the lead is led to the lower die. The frame 13 is set, and the pot portion 22a is set.
The resin tablet 12 is put in the mold and the mold is clamped again. When the softening (partially melting) of the resin tablet 12 starts, the plunger 11 rises and the resin tablet 12 is
a. As the plunger 11 rises, the resin tablet is compressed and the softening and melting of the resin progress, and the resin in the flowing state flows from the cull portion 21 a to the runner portion 24 sequentially. Further, the plunger 11 rises to feed the resin under pressure, and the resin in which the melt viscosity is reduced in the runner portion 24 to be in an optimal flow state passes through the gate 25 and is filled into the upper cavity 26 and the lower cavity 27. After the molded product is solidified while maintaining this state, the molding die is opened, the plunger 11 is further raised to the upper surface of the pot portion 22a, and at the same time, the ejector pins 9 and 10 are raised to remove the cull, the runner and the molded product from the lower mold. Type 2
Release from 2.

[0011]

However, in the above-mentioned mold structure of the prior art, since all the runner portions are directly branched from the cull portion, the resin flowing through the runner is insufficiently melted, or the resin flowing through the runner is not sufficiently melted. And a portion of the resin that has been cured by contact with air in a molten state in the resin. In the conventional example of FIG. 6, molding conditions (long mold temperature) with a long gelling time (a) shown in FIG. 7 are adopted in order to enable molding. As a result, the injection filling process is performed in a state in which the resin is still mixed with unmelted parts, and it is difficult to mold with stable quality due to quality variations of the molded product and reduction in yield. Had.

In the above-mentioned molding die, the cavity 5 filled with resin from the gate 53 first branched from the runner 52.
It is known that molding defects such as voids due to entrainment of air and chipping of resin due to unfilling frequently occur. As an improvement technique, a resin sealing device disclosed in Japanese Utility Model Publication No. 3-45781 is disclosed. However, also in this technique, the runner has a structure directly branched from the cull portion, and the resin flowing through the runner contains air or air therein. Since the resin reaches the gate while containing insufficiently molten resin, variation in molding quality is inevitable.

In the resin mold for multi-plunger described in Japanese Patent Application Laid-Open No. 63-72516, the runner 72 having a longer resin flow path is formed in the mold, so that the mold becomes larger. In addition, the resin that has been melted to have a low viscosity due to the melting of the portion touching the mold flows through the runner 72 at a stretch, and when it reaches the gate 73, the air or the insufficiently melted resin is contained inside. It was in a state and quality control was difficult.

Further, in the resin sealing mold described in Japanese Utility Model Publication No. 3-40579, each pot is communicated with a runner in order to equalize the filling pressure in the plurality of pots. , The runner to the cavity side is pot (cull part)
Branches directly from. Therefore, similar to the conventional example described above,
Since the resin flows through the runner before the resin viscosity reaches the optimum viscosity range shown in FIG. 7B, the quality problem that occurs is also the same as that of the above-described conventional technology, and it is difficult to maintain stable quality. Had.

The molding die of the multi-pot type shown in FIG.
Is raised to compress the resin tablet 12 to advance the melting of the resin and flow the resin directly from the cull portion 21a to the runner portion 24. The resin flowing through the runner portion 24 has insufficient air and insufficient melting. The quality problems (occurrence of voids, chipping of the resin) that occur due to the mixture of the resins are the same as those of the above-mentioned conventional molding die.

The present invention solves the above-mentioned problems, and does not cause voids due to entrainment of air and chipping of resin due to unfilling.
An object of the present invention is to provide a thermosetting resin molding die capable of performing stable molding suitable for resin sealing by low-pressure molding.

[0017]

According to the present invention, there is provided a thermosetting resin molding die according to the present invention, wherein a resin flow path heated and melted in a pot portion and fed by a plunger is provided in a lower die. Part, the gap formed by the end face of the pot tip formed in a convex shape from the parting surface of the lower mold and the bottom surface of the concave part in which the outer periphery provided in the upper mold overlaps the runner part, A resin reservoir which is a space provided on the upper mold side surrounded by the inner peripheral surface of the concave portion of the upper mold, the parting surface of the lower mold, and the outer peripheral side surface of the tip of the pot, and a runner portion communicating with the resin reservoir. It is characterized by being formed in order.

A single-pot type thermosetting resin molding die having one pot in one die, wherein at least one mating surface of an upper die and a lower die near an outer periphery of the resin reservoir. , An air vent is provided.

A multi-pot type thermosetting resin molding die having a plurality of pots in one die, wherein all of the resin reservoirs communicate with each other.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a main part of a thermosetting resin molding die according to the first embodiment. FIG.
FIG. 2A is a plan view of a main part of a lower mold of a single pot type molding die according to a second embodiment, and FIG. 2B is a view of FIG. 2A in which an upper mold is set on the lower mold. It is sectional drawing in the AA position. FIG. 3A is a plan view of a main part of a lower die of a multi-pot type molding die according to a third embodiment.
3B is a cross-sectional view taken along the line AA in FIG. 3A, and FIG. 4 is a plan view of a main part in which an upper cavity surface of an upper mold paired with the lower mold is an upper surface.

Embodiment 1 will be described. In FIG. 1, 1 is an upper mold, 2 is a lower mold, 12 is a resin tablet before melting, 2a is a pot portion for heating and melting the resin tablet, and 4 is a ring-shaped space provided on the upper mold side. Is a gate through which the molten resin flows from the pot portion 2a to the resin pool 4, 0.1 mm to 0.5 mm.
A gap having an optimum dimension of 0.2 mm to 0.3 mm, 1a is a receiving surface of the resin tablet, an upper surface of the gap 3 and a concave portion forming an upper surface and an outer wall surface of the resin reservoir 4, and 2b is a gap 3 in which molten resin flows. 2c is a convex portion that forms the inner wall surface of the resin reservoir 4, 5 is a runner portion that is a resin flow path from the resin reservoir 4 to the gate, 6 is a gate that injects resin into the cavity, Reference numeral 8 denotes a temperature control hole into which a heat medium such as a heater for raising the temperature of a molding die is inserted, 9 denotes an ejector pin for discharging a molded product, 10 denotes an ejector pin for discharging a runner portion, 11 denotes a plunger for feeding resin. 13
Is a lead frame on which an IC is mounted, and is loaded in the lead frame guide groove 2a. In other words, the flow path of the molten resin is such that the pot portion provided in the lower mold, the end face of the pot tip formed in a convex shape from the parting surface of the lower mold, and the outer periphery provided in the upper mold overlap the runner portion. A space formed on the upper mold side surrounded by a gap formed by the bottom surface of the wrapped concave portion, the inner peripheral surface of the concave portion of the upper mold, the parting surface of the lower mold, and the outer peripheral side surface of the tip of the pot. And the resin puddle
It is characterized in that it is formed in the order of runner portions communicating with the resin reservoir.

In the resin sealing molding using the molding die shown in FIG. 1, the molding die attached to the molding machine is
The heater set in the temperature control hole 8 of the molding die is heated.
After the molding die is heated to a predetermined molding temperature, the upper die 1 and the lower die 2 are opened, and the resin tablet 12 is put into the pot portion 2a. Subsequently, a lead frame 13 on which an IC is mounted is loaded into a lead frame guide groove 2d provided in the lower mold 2, and the lower mold 2 is raised to perform mold clamping. At this point, the resin has started to soften due to the heat of the molding die, and the plunger 11 is raised to compress the resin tablet 12.
The resins in the resin tablet 12 adhere to each other and melt. Further, the plunger 11 is raised to feed the resin that has begun to melt. The flowing resin passes through the gap 3 and fills the resin pool 4. During that time, the resin softens and melts, and the viscosity decreases to the optimum viscosity range b shown in FIG.

Subsequently, the resin having the viscosity in the above-mentioned optimum viscosity range b and having improved fluidity is supplied to the runner portion 5 provided in the lower mold 2.
And flow instantaneously through the gate 6 and pass through the upper cavity 61,
The lower cavity 62 is filled. The molded product that has solidified after a holding time for curing is collected by ejecting the ejector pins 9. Further, the runner is discharged by the ejection of the ejector pin 10. The resin remaining in the pot portion 2a after the resin has solidified is moved from the plunger 11 to the pot portion 2a.
The pot is then raised to the position of the tip 2b and discharged to complete the molding process.

Embodiment 2 will be described. FIG.
(A), (b), 2a, 3, 4, 9, 10, 1
1 and 12 are the same components as those in FIG. 1, and the description is omitted using the same reference numerals and names. Reference numeral 20 denotes an upper mold, 30 denotes a lower mold, and 31 denotes a plane portion having a stepped portion which is lower by 10 μm to 30 μm from the parting surface.
An air vent 32 for allowing air to escape from the vicinity of the air vent 32, a stepped portion further lowered by 100 μm to 500 μm from the air vent 31 and an opening for communicating the air vent 31 with the outside and discharging air, and a flow passage 34 for the completely molten resin A runner portion which is a path, 33 is an air vent which allows only air to escape from the end of the runner portion 34, 35 is a gate for filling the cavity with resin, 37 is a product-shaped cavity, 40 is a resin reservoir 4 and the lower mold 30 is in contact with the lower mold 30. The outer peripheral position is shown. The air vent is provided between the upper mold 1 and the lower mold 2 near the outer periphery of the resin reservoir 4.
May be provided on at least one of the mating surfaces.

In the molding using the single-pot type molding die shown in FIG. 2, the steps up to the passage of the resin through the gap 3 are the same as those in the first embodiment. The air in the flow path and the gas generated from the resin are pushed by the molten resin while filling, and the air vent 3
1 to the outside through the opening 32. When the resin pool 4 is completely filled with the resin, the resin is in the optimum viscosity range b. The air in the flow path and the gas contained in the molten resin are continuously discharged to the outside, and the low-viscosity resin easily flows through the runner section 34 and is filled into the cavity 37 from the gate 35 at a low pressure. Air and gas remaining in the runner section 34 are discharged from the air vent 33 to the outside of the mold.

Embodiment 3 will be described. FIG.
4A and 4B and FIG. 4, reference numeral 14 denotes a guide groove for releasing the shape of the lead frame so that the surface of the lower mold 2 and the surface of the lead frame coincide with each other; 15 a guide pin for positioning the lead frame to be inserted; Reference numeral 16 denotes an outer peripheral position of the concave portion 1a overlapping the runner portion 5, 41 denotes an upper cavity, and 42 denotes a lower cavity. 1b is a guide pin escape hole corresponding to the above-described guide pin 15, and other parts are the same components as those in FIG. 1, so the description is omitted using the same reference numerals and names.

The molding step of the third embodiment using a multi-pot type molding die is the same as that of the first embodiment, except that the upper mold filled with the resin pressure-fed from the plurality of pot portions 2a is used. Adjacent peripheral portions of the plurality of resin pools 4 formed in the concave portion 1a of the mold 1 overlap with each other,
The plurality of resin reservoirs 4 communicate with each other. The resin flowing from the gap 3 fills the plurality of resin pools 4 on the upper mold 1 side, and the softening and melting proceeds. Before the resin reaches the runner section 5 on the lower mold 2 side, the resin melted in the plurality of resin pools 4 is integrated at the above-mentioned communication portion and flows to the plurality of runner sections 5. At this time, the melt viscosity and the flow pressure of the resin become the same.

[0028]

As described above in detail, the thermosetting resin molding die according to the present invention has a structure in which the resin flow path communicates with the runner part from the pot part through the resin reservoir, so that the resin is During the filling of the resin pool, the softening and melting progresses to the optimum viscosity range, and the resin passes through the gate at the lowest pressure and fills the cavity. In addition, the air vent from the resin pool and the air vent at the end of the runner section ensure that air and gas are removed while the flowing resin reaches the gate of the cavity, so that good molded products without voids and resin chips can be easily obtained. Is now available. In the case of a multi-pot type mold, a plurality of resin reservoirs are connected to each other to form an integrated structure, so that when the resin is completely melted and flows through a plurality of runner portions, the state of the resin becomes the same, and the resin is transferred to a plurality of cavities. Can be filled with the same molding conditions. By employing the above structure, it is possible to provide a thermosetting resin molding die capable of performing stable molding suitable for resin sealing by low-pressure molding without causing voids due to entrainment of air or chipping of resin due to unfilling.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a thermosetting resin molding die according to a first embodiment of the present invention.

FIG. 2 is a plan view and a partial cross-sectional view of a main part of a lower die of a single-pot type molding die according to a second embodiment of the present invention.

FIG. 3 is a plan view and a partial cross-sectional view of a main part of a lower die of a multi-pot type molding die according to a third embodiment of the present invention.

FIG. 4 is a plan view of a main part of the third embodiment of the present invention, in which an upper cavity surface of an upper mold that is paired with the lower mold is an upper surface.

FIG. 5 is a sectional view of a main part of a conventional multi-pot type molding die.

FIG. 6 is a plan view showing a resin flow path of a conventional single-pot type thermosetting resin molding die.

FIG. 7 is a diagram showing a curing characteristic of a resin in a molding step using a thermosetting resin molding die.

FIG. 8 is a plan view showing a resin flow path of a conventional multi-pot type resin sealing mold.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 upper mold 1a recess 2 lower mold 2a pot 2b pot tip 2c convex 3 gap 4 resin pool 5 runner 6 gate 8 temperature control hole 9,10 ejector pin 11 plunger 12 resin tablet 61 upper cavity 62 lower cavity

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 31:34

Claims (3)

[Claims] In a molding die of a thermosetting resin, a resin flow path heated and melted in a pot portion and fed by a plunger is provided.
The bottom portion of the pot portion provided on the lower mold, the end surface of the tip portion of the pot formed in a convex shape from the parting surface of the lower mold, and the outer periphery provided on the upper mold overlap with the runner portion. And a resin pool which is a space provided on the upper mold side surrounded by the inner peripheral surface of the concave portion of the upper mold, the parting surface of the lower mold, and the outer peripheral side surface of the tip of the pot, and the resin A thermosetting resin molding die formed in the order of runner portions communicating with the pool. 2. A single-pot type thermosetting resin molding die having one pot per one die, wherein at least one mating surface of an upper die and a lower die near an outer periphery of the resin reservoir. The thermosetting resin molding die according to claim 1, further comprising an air vent. 3. A thermosetting resin molding die of a multi-pot type having a plurality of pots in one die, wherein all of the resin reservoirs communicate with each other. Curable resin molding die.