JP3147967B2 - Lead frame resin molding method and molding die - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding method and a mold for a lead frame.

[0002]

2. Description of the Related Art In a transfer molding apparatus which is generally used as an apparatus for resin-molding a lead frame, a molding die having a cavity for sealing a semiconductor element and a resin path connecting a pot and the cavity is provided. And resin molding. The resin path extends in the width direction on the lead frame from one side edge of the lead frame and communicates with the cavity. By the way, in the case of a matrix frame in which a plurality of rows of resin mold sections are formed on one lead frame, a plurality of resin mold sections are arranged in the width direction. It is necessary to extend the resin path from one side edge of the frame in the width direction. FIG. 1 shows an example of this type of lead frame, in which a runner extends in the width direction in the middle of an adjacent resin mold portion, and a gate is branched from the runner to each cavity to connect the pot and the cavity.

[0003] As described above, the cavity and the pot are connected to each other through the resin path extending on the lead frame as described above, and each cavity is filled with molten resin from the pot and resin-molded. After the resin molding, the resin cured in the resin path on the cull and the lead frame remains attached to the lead frame. For this reason, after performing resin molding, these unnecessary resins are peeled and removed from the lead frame. In this peeling and removing step, the resin (runner, gate) cured on the lead frame in addition to the curl is peeled and removed, and only the resin mold portion remains on the lead frame.

[0004]

In the above-described degate process, if the resin adheres to an unnecessary portion and remains, the die may be damaged by lead forming or the like in a later process. Unnecessary resin must be removed. In the case of the above-described matrix frame and the like, there is a problem that degate is difficult because a long runner adheres to the lead frame after resin molding, and in order to solve this, the degate is performed by protruding the runner portion with pins at a plurality of places. Method (JP-A-3-184351)
Etc. have been proposed. However, depending on the mold resin, the adhesion between the lead frame and the resin is high. If the resin path remains on the lead frame for a long time such as in a matrix frame, it becomes more difficult to remove and remove the cured resin. And the lead frame is deformed during peeling and removal. Therefore,
The present invention has been made to solve the above problems,
An object of the present invention is to provide a resin molding method for a lead frame and a molding die, which can solve the problem of peeling and removing the cured resin from the lead frame after the resin molding.

[0005]

The present invention has the following arrangement to achieve the above object. That is, when a resin path is extended from one side edge of the lead frame to the lead frame in the width direction on the lead frame, and the resin is molded, a cured resin cured in the runner path near the side edge of the lead frame is formed. A constricted portion for forming a V-notch portion is provided to transfer the resin, and after the resin is cured, the V-notch portion is bent as a bending position between the cull and the cured resin cured in the runner path to form a runner on the lead frame. The cull is separated and removed from the lead frame while the cured resin is adhered in the resin path such as a path. Further, in a mold for extending a runner path connecting the pot and the cavity from one side edge of the lead frame in the width direction, and clamping the lead frame and performing resin molding, in a mold near the one side edge of the lead frame, In the runner path, after the resin is cured, a constricted part for forming a V notch part in the cured resin for separating and removing the cull while attaching the resin cured in the resin path such as the runner path on the lead frame on the lead frame is provided. It is characterized by having. Further, as a mold, a runner path having the constricted portion is provided on one of a pair of molds for resin molding by clamping a lead frame, and a position facing the other mold with the lead frame interposed therebetween. The one provided with a runner path for preventing warpage having substantially the same volume as the one runner path, the runner path provided in the mold,
In order to release the distortion between the lead frame and the hardened resin after the hardening of the resin, it is effective to provide a V-projection for bending the hardened resin in the runner path to form a V-groove for cracking the hardened resin. It is.

[0006]

After the lead frame is molded with resin, the cured resin is bent at the V-notch portion of the cured resin cured in the runner path in the decal removal step, and the cull is separated from the cured resin and removed from the lead frame. By bending the cured resin at the V-notch portion, cracks are easily formed and the cull can be separated. The resin cured in the resin path, such as a runner, remains on the lead frame as it is, and in this state, it is transferred to a subsequent process. In a post-process such as lead forming, work can be performed by removing the cured resin from the lead frame. By providing a runner path for preventing warpage with respect to the runner path connecting to the cavity in the opposite mold, it is possible to prevent the cured resin remaining on the lead frame from peeling off from the lead frame and dropping, The warpage of the lead frame is suitably prevented. When resin molding is performed by providing a V-groove, by bending the cured resin at the V-groove portion after the resin molding and cracking the resin, the warp stress of the lead frame can be released.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a state in which the lead frame is resin-molded and the mold is opened by the resin molding method for a lead frame according to the present invention. Lead frame 1
Reference numeral 0 denotes a product in which the resin mold portions 14 are arranged in two rows. The runner 16 extends from one side edge of the lead frame 10 on the side of the pot 12 to the middle of the adjacent resin mold portion 14, and enters each cavity via the gate 18. I'm in contact. The gate 18 is connected to a corner of the resin mold section 14.

In the embodiment, the gate 18 is the lead frame 1
The runner 16 running on the upper surface of the lead frame 10 once branches laterally, descends from the lock hole 20 to the lower surface side of the lead frame 10, and communicates with the cavity from below. The lock hole 20 is formed in the lead frame 10 so as to fill the cavity with resin from the lower side of the lead frame 10. The resin hole injected into the cavity is provided by bending the resin path from the upper surface to the lower surface. The purpose is to increase the kneadability of the resin and to provide a resin path on the lower surface of the lead frame 10 to make it difficult for the resin cured on the lead frame 10 to fall from the lead frame 10. In the resin molding method for a lead frame according to the present invention, the resin cured in the resin path such as a runner path is kept attached to the lead frame, so that the resin attached to the lead frame may damage the mold in a later process. It is necessary to ensure that it adheres to the lead frame in order to prevent it from occurring.

FIG. 2 is a sectional view showing a state in which the lead frame 10 is resin-molded. The pot 12 is filled with resin by a runner path 16a running on the upper surface of the lead frame 10, but in this embodiment, the upper mold runner path 16a is used.
A runner path 22a for preventing warpage of the lead frame is provided in the lower die in accordance with the arrangement position of the lead frame. In order to allow the resin to enter the runner path 22a, a square hole 24 (broken line) communicating with the runner path 22a is previously formed in the lead frame 10 as shown in FIG. In the embodiment, the square holes 24 are provided at substantially the same width as the runner path 16, and the runner paths 22a are provided at two places as shown in FIG. In the conventional resin molding method, the runner path is provided on one side of the lead frame to separate and remove the resin cured in the runner path from the lead frame after the resin molding, but in this embodiment, the runner path is sandwiched between the lead frame 10 and the runner path. By providing the paths 16a and 22a, the resin cured on the lead frame 10 is hardly peeled off from the lead frame 10 positively. In addition, if the cured resin is applied only to one side of the lead frame 10, the lead frame warps after the resin is cured,
By arranging the runner passages 22a so as to face each other with substantially the same thickness as that of the runner passages 16, warpage of the lead frame can be prevented. Reference numeral 26 denotes an eject pin provided on the upper mold, and reference numeral 28 denotes an eject pin provided on the lower mold.

In the resin molding method for a lead frame according to the present invention, after the resin is transferred to cure the resin, the cull is removed from the lead frame and sent to a subsequent process.
Therefore, the connecting portion between the cull 12a and the runner 16 has V
Resin molding is performed so as to provide the notch portion 30. As shown in FIG. 2, the V-notch portion 30 is a portion where the cross-sectional shape of the runner path 16 is narrowed in a V-shape, and a constriction portion for providing the V-notch portion 30 is provided in a mold. After the resin is cured, the curl 12a can be easily separated and removed from the lead frame 10 by bending the cured resin with the V-notch portion 30 as a bending position in a cull removing step. The V-notch portion 30 is preferably provided at a position slightly inside from the side edge of the lead frame 10 as shown in FIG. By providing the lead frame near the side edge, the cull can be easily separated simply by twisting the lead frame 10.

FIG. 3 shows a state where the cull is removed from the lead frame 10 after the resin is cured. The cull is removed at the V-notch portion 30, and the runner 16 and the warp prevention runner 22 are attached on the lead frame 10. The gate 18 is also attached to the lower surface of the lead frame 10. Since the runners 16 and 22 and the gate 18 are attached to both sides of the lead frame 10, these resins do not separate from the lead frame 10, and the resin separates when the lead frame is transferred to a subsequent process. Problems caused by falling can be solved. In a post-process such as lead forming, first, unnecessary runners 16 and 22 and gate 1
After removing the resin of the eight portions and removing these resin portions, a process such as ordinary lead forming may be performed. In some cases, it is also possible to process while the cured resin is attached to the lead frame 10.

In the above embodiment, the runner path 16a and the warp prevention runner path 22a are provided and resin-molded in order to prevent the cured resin adhering to the lead frame 10 from being separated and dropped from the lead frame 10. In the case where the resin thickness of the upper and lower surfaces of the lead frame must be unbalanced due to the design of the lead frame, or when the runner is provided only on one side of the lead frame as in the conventional example, as shown in FIG. V on the way to runner 16
A method of providing the groove 32 and performing resin molding is effective. In this case, a V-projection is provided in the runner path of the mold, and resin molding is performed. According to this method, when the lead frame warps as shown in FIG. 4B after the resin molding, the lead frame is pushed and bent in the opposite direction to crack the V-groove 32 to eliminate the warping stress. By cracking the cured resin, stress can be eliminated and warpage can be prevented.

[0013]

According to the lead frame resin molding method of the present invention, as described above, the resin cured on the lead frame is directly adhered to the lead frame to cure the runner or the like from the lead frame. The problem of removing and removing the resin can be eliminated. In addition, it is possible to solve the problem that the unnecessary resin remains on the lead frame after the peeling and removal, or the unnecessary resin drops into the mold during transportation and damages the mold. Further, by providing a runner path on both surfaces of the lead frame and performing resin molding, or by providing a V groove in the runner, it is possible to prevent the cured resin from peeling and falling from the lead frame, and to prevent warpage of the lead frame. It has significant effects such as being able to do.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a resin molding method for a lead frame.

FIG. 2 is a cross-sectional view of a state where a lead frame is resin-molded.

FIG. 3 is a sectional view showing a state where a cull is removed from a lead frame.

FIG. 4 is an explanatory view showing an example in which a runner is provided with a V-groove.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lead frame 12 Pot 12a Cul 14 Resin mold part 16 Runner 16a Runner path 18 Gate 20 Lock hole 22 Warpage prevention runner 22a Runner path 24 Square holes 26 and 28 Eject pin 30 V notch part 32 V groove

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-210838 (JP, A) JP-A-2-9142 (JP, A) JP-A-2-5538 (JP, A) JP-A-60-1985 43836 (JP, A) JP-A-3-255639 (JP, A) JP-A-58-20427 (JP, A) JP-A-3-297613 (JP, A) Japanese Utility Model Publication No. 54-65968 (JP, U) Shokai Sho 63-37211 (JP, U) JP-B Sho 53-21 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/02

Claims (4)

(57) [Claims] When a resin path is extended from one side edge of the lead frame to the lead frame in the width direction and molded with resin, the resin is hardened in the runner path near the side edge of the lead frame in the runner path. By providing a constricted portion for forming a V-notch portion in the cured resin and transferring the resin, after the resin is cured, the V-notch portion is bent as a bending position between the cull and the cured resin cured in the runner path, thereby forming a lead frame. A resin molding method for a lead frame, wherein a cull is separated and removed from a lead frame while a resin cured in a resin path such as a runner path is adhered thereon. 2. A mold for extending a runner path connecting a pot and a cavity from one side edge of a lead frame in a width direction, clamping the lead frame, and resin-molding the lead frame. A constriction for forming a V-notch portion for separating and removing the cull in the runner path at the position after the resin is cured and the resin cured in the resin path such as the runner path on the lead frame on the lead frame. A mold provided with a part. 3. A runner path having the constricted portion is provided in one of a pair of mold dies for clamping and molding the lead frame with a resin, and the other mold die is provided at a position facing the sandwiched lead frame with the other mold. 3. A mold according to claim 2, further comprising a runner path for preventing warpage having substantially the same volume as that of said runner path. 4. A V-groove for cracking the cured resin by bending the cured resin in the runner path so as to release the distortion between the lead frame and the cured resin after curing the resin in the runner path provided in the mold. 3. The mold according to claim 2, further comprising a V-projection for forming a groove.