JPH05335442A - Resin molding method for semiconductor - Google Patents

Abstract

PURPOSE:To restrain generation of burr to a minimum, and prevent generation of void, by forming a metal-plated layer in the manner in which the layer thickness in a resin seal space and a specified region exceeding the space is made larger than the layer in a tip region protruding from the specified region. CONSTITUTION:After a space containing a semiconductor element is formed by making a punch 1 abut against a lower die 2, resin is injected in a resin seal space 5 and cured. Metal-plated layers 10a, 10b are formed in the manner in which the layer thickness in the resin seal space 5 and a specified region exceeding the resin seal space 5 is made larger than the layer in a tip region protruding from the specified region. That is, a step-difference is formed in the parts of the metal plated layers 10a, 10b of the upper surface and the lower surface of an outside lead frame 7 exceeding the resin seal space 5 to be resin sealed. By the effect of the step-difference, a gap is formed between the punch 1 and the lower die 2, and gas generated from sealing resin is discharged from the gap to the outside.

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 for semiconductor devices, and more particularly to a transfer molding method for molding a resin such as a light emitting diode using a transparent resin or a colored resin.

[0002]

2. Description of the Related Art FIG. 4 is a schematic sectional view of a conventional example, and FIG. 5 is a schematic plan view thereof. A semiconductor element (not shown) such as a light emitting diode is placed on a mounting table (not shown) on the lead frame 17, and resin molding is performed in a state in which the semiconductor element and the lead terminal are wired. .. First, the resin injection gate 16 and the molding resin are injected by joining the upper mold 11 having the upper package 13 and the lower mold 12 having the lower package 14 with the lead frame 17 interposed therebetween. The resin sealed space 19 is formed. Further, an air vent 18 is formed in the upper package 13, and the gas in the resin injected into the resin sealing space 19 is exhausted through the air vent 18.

Resin sealing is performed using the mold having the above structure. That is, the resin is injected into the resin sealing space 19 from the resin injection gate 16 via the runner 15. At this time,
The air bubbles that have entered the resin-sealed space 19, that is, the product portion, are discharged through the air vent 18 by the resin pressure. In this way, it is possible to prevent air bubbles from entering the product section.
Conventionally, such a method has been used to prevent the occurrence of voids in the product and improve the quality.

Further, as shown in FIG. 6, the lead frame 1
A method of forming a metal plating layer 60 on each of the upper surface and the lower surface of 7 with a uniform thickness, mounting a semiconductor element on the metal plating layer 60, and performing resin sealing in the same manner as above is also performed. There is.

[0005]

Although the conventional technique is effective as a method for preventing the occurrence of voids,
This is a problem in that it causes the generation of resin burr. In other words, it is effective when a resin that does not flow easily is used, but there is a problem that resin burr is likely to occur when a resin that flows easily and that enters even a small gap is used.
Further, even if the resin burrs can be sufficiently prevented when the molding dies are new, there is a problem that resin burrs are likely to occur due to wear of the dies and variations in the die surface pressure due to aging. ..

The present invention has been made in view of these points, and it is an object of the present invention to provide a resin molding method for a semiconductor device capable of minimizing the generation of resin burrs and preventing the generation of voids. To aim.

[0007]

In order to achieve the above object, in the resin molding method for a semiconductor device of the present invention, a semiconductor element is placed on a lead frame and the semiconductor element and the lead terminal are connected. In this state, a space containing the semiconductor element is formed by abutting an upper die and a lower die, and then a resin is injected into the resin encapsulation space and the resin is encapsulated by curing the resin mold of a semiconductor device. In the method, before the resin sealing, the metal plating layer to be formed on the upper surface and the lower surface of the lead frame is projected from the predetermined region beyond the thickness of the resin sealing space and the predetermined region exceeding the resin sealing space. Characterized by making the thickness in the tip region thin.

[0008]

A step is formed in the metal plating layer portion on the upper surface and the lower surface of the lead frame outside the resin-sealed space to be resin-sealed, and the step forms a gap between the die and the lead frame. The gas generated from the resin to be sealed is discharged to the outside through this gap.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of an essential part for explaining an embodiment of the present invention, and FIG. 2 is a plan view for explaining an embodiment of the present invention. 3 is a sectional view for explaining the method of the embodiment of the present invention, showing a state in which a metal plating layer is formed on the lead frame.

Embodiments of the present invention will be described below with reference to these drawings. First, as shown in FIG. 3, metal plating is applied to the upper surface and the lower surface of the lead frame 7. This metal plating is applied thickly on the top and bottom surfaces of the lead frame 7 inside and outside the resin-sealed space 5 including the portion where the semiconductor element is molded, and on the top and bottom surfaces of the lead frame 7 outside thereof. By applying, the thick plating layer M1 and the thin plating layer M2 are formed, respectively. Therefore, the boundary between the thick plated layer M1 and the thin plated layer M2 has a stepped structure.

Next, a semiconductor element such as an LED is mounted on the thick plated layer M1 (not shown), and the semiconductor element and a lead terminal (not shown) are internally connected. Thereafter, as described below, the semiconductor element in this state is sealed with resin.

First, as shown in FIG. 1, a resin sealing space 5 is formed.
Forming an upper package 3 and a lower package 4, respectively, and forming a metal plating layer 1 on the upper mold 1 and the lower mold 2.
The lead frames 7 on which 0a and 10b are formed are abutted with each other in a sandwiched state. By abutting the two molds 1 and 2 in this manner, gaps 10a and 10b are formed between the thin plating layer M2 and the upper mold 1 and between the thin plating layer M2 and the lower mold 2, respectively. .. In this state, the resin sealing space 5
The resin is injected through the runner 15 into the resin injection gate 16
The resin is injected from above and the resin is sealed. At the time of this resin sealing,
The resin in the resin sealing space 5 oozes into the gap between the external lead frames 7, and a frame thickness resin burr 21 is generated.
On the other hand, the gas in the resin is gradually discharged through the frame thickness resin burr 21 due to the high resin pressure resistance and further through the gaps 10a and 10b.

As described above, although resin burrs are generated in the embodiment of the present invention, they are not generated on the lead frame. Therefore, it is easy to remove burrs in a later step.
It does not cause quality deterioration such as scratching the product.

Further, the resin applied in this embodiment is effective for resin encapsulation using a resin having a good flowability such as a transparent resin, so that it can be applied particularly to a light emitting diode and a light receiving element.

[0015]

As described above, according to the resin molding method of the present invention, a step is formed in the metal plating layer on the outer side of the resin-sealed space to be resin-sealed. Since a gap is formed between the lead frame and the lead frame and the gas generated from the resin is discharged to the outside through this gap, the resin does not seep out onto the lead frame during resin encapsulation and the resin burr is greatly removed. Can be reduced to Therefore,
The work such as the removal of the resin burr is not reduced, and the process can be simplified. Further, it is possible to avoid troubles in the transfer system due to resin burr. In addition, when manufacturing the mold, there is no need for a processing step to provide an air vent, so the processing cost is reduced, and by applying differential thickness plating to the lead frame, the cost of the lead frame can also be reduced. The manufacturing cost can be reduced as a whole.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part for explaining an embodiment of the present invention.

FIG. 2 is a plan view of a main part for explaining an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state where a metal plating layer is formed on the lead frame used in the example of the present invention.

FIG. 4 is a sectional view of a main part for explaining a conventional example.

FIG. 5 is a plan view of a main part for explaining a conventional example.

FIG. 6 is a sectional view of an essential part for explaining another conventional example.

[Explanation of symbols]

 1 ... ・ Upper mold 2 ・ ・ ・ ・ Lower mold 3 ・ ・ ・ ・ Upper package 4 ・ ・ ・ ・ Lower package 5 ・ ・ ・ ・ Resin-sealed space 7, 9 10b ... Metal plating layer

Claims (1)

[Claims] 1. A semiconductor element is mounted on a lead frame,
After the semiconductor element and the lead terminal are connected, a space containing the semiconductor element is formed by abutting the upper die and the lower die, and then a resin is injected into the resin-sealed space and cured. In a resin molding method for a semiconductor device which is resin-sealed by means of the above, before the resin-sealing, a metal plating layer to be formed on the upper and lower surfaces of the lead frame is formed in the resin-sealing space and a predetermined region exceeding the resin-sealing space. A resin molding method for a semiconductor device, characterized in that a thickness in a tip region protruding from a predetermined region is formed thinner than a thickness.