JPH06244228A - Lead frame and resin sealing mold thereof - Google Patents

Abstract

PURPOSE:To provide the title resin sealing mold of semiconductor element having excellent molding capacity and lead frame shape while settling the point at issue of running resin into a gap between lead frame outside and a mold force during the resin molding step of the semiconductor element. CONSTITUTION:Within the mold top and bottom forces A, B and a lead frame D during the resin sealing step of a semiconductor element, a protrusion J shapedly provided inside the lead frame D side in the same level as that of the frame thickness is arranged on the bottom force B in both end parts of a runner part G. Furthermore, a recession K opposing to a projection J of the bottom force B is provided in the lead frame outside while a crushing space M protruding in the gap L between the projection J of the bottom B and the lead frame outside recession K is provided in both parts of the runner G of the lead frame outside recession K so that a projection to cruch the crushing space M may be provided in the top force A when the mold top and bottom forces A, B are engaged with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing process, and more particularly to the shapes of a mold and a lead frame in a resin sealing process for a semiconductor element.

[0002]

2. Description of the Related Art A conventional semiconductor element sealing process will be described with reference to FIGS. 2 is a sectional view showing a conventional method for sealing a semiconductor element, FIG. 3 is a plan view of a conventional lead frame after resin encapsulation seen from above, and FIG. 4 is a plan view of FIG. 2 seen from above. 5 is an external view of the resin-sealed semiconductor device.

As shown in FIG. 2, in a conventional semiconductor element encapsulation process, first, a lead having a semiconductor element mounted in a cavity C formed when an upper mold A and a lower mold B of a mold are closed together. The frame D is positioned at a predetermined position of the mold, and then the upper mold A and the lower mold B of the mold are fitted together.
Then, after holding the upper and lower molds A and B in a state of being heated to a constant temperature, a cylindrical solidified epoxy resin is put into the pot E, and the plunger F presses the runner portion G to the gate H, and further the semiconductor element. Epoxy resin is injected into the set cavity portion C. The resin injected into the cavity C requires a certain time (about 45 to 60 seconds) after the filling is completed and before it is molded (solidified). During this time, the plunger F is in the pressed state. After resin molding is completed,
The upper and lower molds A and B are opened and the molded product is taken out.

FIG. 3 shows the shape of the lead frame after molding with resin. 1 is a mold resin package,
Reference numeral 2 is a tie bar, 3 is an external lead, 4 is an outer frame of a lead frame, 5 is a dam portion for collecting unnecessary resin, and 6 is a positioning guide hole.

FIG. 4 shows the relationship between the lead frame and the mold. As for the method of positioning the lower die B and the lead frame, guide pins (not shown) provided on the lower die B are provided with four circular positioning guide holes 6 provided at both ends of the outer frame 4 of the lead frame. As a result, the lower die B and the lead frame are positioned. In the state where the frame and the mold are positioned, a gap I of about 0.05 mm is provided between the outer side of the outer frame 4 of the frame and the lower mold B in consideration of manufacturing tolerances of the lead frame. ing.

Here, the resin-molded semiconductor device shown in FIG. 3 is then subjected to processes (not shown) such as removing unnecessary resin debris from the dam portion 5, punching the tie bar 2, punching the outer periphery of the outer frame 4, and lead bending. A semiconductor device having the appearance shown in FIGS. 5A to 5C is manufactured.

[0007]

However, when the resin molding process is performed with the mold and the lead frame having the above-described structure, a gap of about 0.05 mm generated between the outside of the frame outer frame and the mold is obtained. The resin flows out to the width and the height corresponding to the frame thickness, and the resin that has flowed out remains on the lead frame. The remaining resin drops off during the subsequent processing steps such as tie bar punching, lead frame outer peripheral punching, lead bending, etc., and during frame transfer, causing cracks and scratches that cause equipment defects. However, there is a problem in that the quality of the semiconductor device is deteriorated due to adverse effects such as bending or bending of the frame.

As described above, the present invention eliminates the problem that the resin flows out into the gap between the outside of the lead frame and the mold during the molding of the semiconductor device by molding resin, and the semiconductor device excellent in molding is obtained. An object is to provide a mold for resin sealing and a lead frame shape.

[0009]

A lead frame resin-sealed by a resin-sealing mold having a cavity formed on a lead frame for accommodating a semiconductor element and a runner for introducing resin into the cavity from the outside. In the lead frame, the runner has convex portions formed at both ends of the crossing portion on the lead frame.

In a molding die for resin encapsulation, which has a cavity for accommodating a semiconductor element formed on a lead frame and a runner for introducing a resin into the cavity from the outside, the molding die defines the shape of the cavity. A resin encapsulation having an upper die and a lower die, wherein the upper die has a close contact portion that is in close contact with a convex portion formed at both ends of a crossing portion on the lead frame across which the runner crosses. Mold for use.

[0011]

With the above construction, in the resin encapsulation step, the present invention first comprises a lower mold die having convex portions on both end portions of the runner portion on the resin injection side, and a lead frame having concave portions at positions facing the convex portions. Perform predetermined positioning with. After the positioning is performed, the lower mold and the upper mold are fitted together. At that time, the crushing space provided on the outer frame of the lead frame is crushed by the protrusions provided on the upper mold, so that a gap between the lower mold protrusions and the lead frame concave portion, that is, the lead frame manufacturing process. A gap that is set in advance in consideration of tolerances and the like is closed, and resin outflow to the outside of the lead frame is prevented.

[0012]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is a plan view showing an embodiment of the present invention. The same parts as those in the conventional example are designated by the same reference numerals.

As shown in FIG. 1, when sealing with resin,
First, the lead frame D on which the semiconductor element is mounted is set in the lower mold B of the mold. At this time, at both end portions of the runner portion located on the runner portion G on the resin injection side, the lower mold B is provided with the convex portion J having the same height as the lead frame D thickness. Further, the lead frame D on the resin injection side is provided with a concave portion K facing the convex portion of the lower mold B. And
A gap L of about 0.05 mm is previously provided between the convex portion J of the lower mold B and the concave portion K of the lead frame D in consideration of manufacturing tolerances of the lead frame D. Further, both end portions of the runner portion located on the runner portion G on the resin injection side of the lead frame D are crushed by the upper die A (see FIG. 2) when the upper and lower sides of the molding die are fitted, and the resin is filled in the gap L. A crushing space M is provided to prevent outflow. Further, when fitting the upper and lower molds, although not shown here, the upper mold A (see FIG. 2)
Is provided with a convex portion that can crush the position of the crushing space M provided at both ends of the runner portion of the lead frame D by about 0.02 to 0.05 mm.

The crushing space M of the lead frame D is
The gap L between the convex portion J of the upper mold A and the convex portion J of the lower mold B is crushed.
To close. 0.02-0.05mm depending on the upper mold protrusion
The state of the crushed space M is shown as N. The N portion prevents the resin from flowing out between the lower mold B and the lead frame D.

In the subsequent steps, the upper and lower molds A and B are heated to a constant temperature in the same manner as in the conventional steps, and then the epoxy resin is applied to the gate from the runner section G to the semiconductor element by pressing the plunger. It is injected into the inside of the stored cavity. After filling the injected resin,
Hold the plunger in the pressed state for a certain period of time (45-60 seconds) until it is molded (solidified), and then press the upper and lower molds A, B.
Open and take out the molded product.

[0016]

As described in the above embodiments, according to the present invention, when the lead frame is set in the upper and lower molds of the mold, the gap formed between the lead frame and the upper and lower molds (clearance in manufacturing the lead frame) is set in the upper and lower molds. Since it has a shape of a lead frame and a mold which are closed when the resin is fitted, it is possible to prevent the resin from flowing out to the outside of the lead frame during the subsequent resin injection. Therefore, it is possible to prevent adverse effects such as cracks, scratches, and bending of the frame that are caused by the resin portion that has flowed out excessively, and it is possible to improve the stable quality and yield of the semiconductor device in the subsequent steps. .

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional method for sealing a semiconductor element.

FIG. 3 is a plan view showing a conventional lead frame shape after resin sealing.

FIG. 4 is a plan view of FIG. 2 viewed from the upper side.

FIG. 5 is an external view of a resin-sealed semiconductor device.

[Explanation of symbols]

 A Upper mold B Lower mold D Lead frame G Runner part J Lower mold protrusion K Lead frame recess L Gap M Space for crushing

Claims (2)

[Claims] 1. A lead frame resin-sealed by a resin-sealing mold having a cavity for housing a semiconductor element formed on the lead frame and a runner for introducing resin into the cavity from outside. 2. A lead frame, characterized in that convex portions are formed at both ends of the crossing portion on the lead frame crossing. 2. A resin sealing mold having a cavity formed on a lead frame for accommodating a semiconductor element, and a runner for introducing resin into the cavity from the outside, wherein the mold has a shape of the cavity. A resin having an upper die and a lower die that define the resin, wherein the upper die has a close contact portion that is in close contact with a convex portion formed at both ends of a crossing portion on the lead frame that the runner traverses. Mold for sealing.