JPS6399539A - Manufacture of resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the inclusion of bubbles in a resin layer and yield of pinholes, by providing a main injection port toward a space in a mold in one surface of the mold, which is vertical to the surface of a substrate on the side of the element of the substrate, and providing an auxiliary injecting port toward the space in a mold in the surface of the neighboring mold, which is vertical to the surface of the substrate on the opposite side of the element of the substrate. CONSTITUTION:Resin is injected through a main gate 6, which is communicated to a main runner 7, and an auxiliary gate 61, which is communicated to an auxiliary runner 71 branched from the main runner 7 and provided in the side surface in a neighboring mold at the close side to the main gate 6. The main gate 6 is directed toward a wide space in the mold having a thickness of d1 on the side of a semiconductor chip 1 of a substrate 2. The auxiliary gate 6 is directed toward a space in the narrow mold having a thickness d2 on the opposite side of the chip of the substrate 2. When the resin is injected through the main gate 6 and the auxiliary gate 61, the space in the narrow mold having the thickness d2 is filled with the resin through both gates in fanwise shapes. Therefore, the resin, which flows into the space in the thin mold, is molded in the direction so as to push out air in the space based on the positional relationship between the main gate 6 and the auxiliary gate 61.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

In the present invention, a metal substrate to which a semiconductor element is fixed is covered with a substantially rectangular resin layer, and in this case, the resin layer covering the surface of the substrate opposite to the element support is made smaller than the resin layer covering the element in order to improve the heat dissipation effect. The present invention relates to a method of manufacturing a resin-sealed semiconductor device that can be made thinner.

[Prior art and its problems]

In a semiconductor device in which a metal substrate supporting a semiconductor element is exposed on the surface and sealed with resin, if it is insulated and fixed on a grounded heat sink, an insulating plate such as mica should be placed between the substrate and the heat sink. I was intervening. In order to eliminate the need for such an insulating plate, a resin-sealed semiconductor device in which an insulating layer is provided on the substrate on the side fixed to the heat sink is shown in Fig. 2 (al is an external view. (b) ) is a cross-sectional view of FIG. 0, a semiconductor chip 1 is brazed to a mounting portion 2 of a lead frame serving as a supporting substrate, and is connected to an external lead portion 21 by a conductive wire 3, with the external lead portion 21 exposed. It is sealed by a resin layer 4 having a mounting hole 8. At this time, the resin layer 4
The thickness d on the opposite side is significantly thinner than the thickness d on the chip side, which improves heat dissipation when this semiconductor device is fixed on a heat sink by the surface 5. Shigashi,
In order to mold such a resin layer 4, when a lead frame is supported in the mold space and resin is injected from the gate 6 provided on the mold surface perpendicular to the mount section 21, due to the difference in layer thickness. The resistance to the resin flow is different, and the resin is
The resin layer with a thickness of d is molded quickly, and the resin layer with a thickness of d on the anti-chip side of the substrate 2 is molded slowly. Since the resin entering directly from the gate 6 on the side and the resin coming from the mold space on the chip side of the substrate 2 meet in the mold space on the opposite chip side, the air in the mold space can be sufficiently removed. No cutting,
Bubbles and pinholes are generated in the resin layer 4. This phenomenon becomes more pronounced as the thickness d2 of the thin resin layer becomes smaller and as the sealing area becomes larger.

[Object of the invention] The present invention solves the above-mentioned problems, and solves the difference in molding speed between the thick resin layer on the semiconductor element side of the substrate and the thin resin layer on the opposite side, and the difference in molding speed in the resin layer that occurs based on the difference in molding speed. It is an object of the present invention to provide a method for manufacturing a resin-sealed semiconductor device that can prevent the inclusion of air bubbles and the generation of pinholes. [Summary of the Invention] The present invention is directed to a main mold which is provided on one of the mold surfaces perpendicular to the substrate surface of a mold having an approximately rectangular parallelepiped space, facing the mold space on the semiconductor element side of the substrate. Injection is performed by an inlet and an auxiliary injection port provided on a side of the mold surface closer to the main injection port and facing the mold space on the side opposite to the element on the mold surface perpendicular to the adjacent substrate surface. This allows the molding speed of the thin resin layer on the side opposite to the element of the substrate to be synchronized with the molding speed of the thick resin layer on the element side, thereby achieving the above object.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention, (a) is a plan view after resin molding, (bl is a cross-sectional view of the completed semiconductor device, and parts common to those in FIG. 2 are denoted by the same reference numerals. As is clear from the figure, the resin is applied to the main gate 6 communicating with the main runner 7 and the auxiliary runner 7 branched from the main runner 7.
1, and is injected through an auxiliary gate 61 provided on the inner side of the adjacent mold on the side closer to the main gate 6. 1), the main gate 6 faces a wide mold space with a thickness d on the chip 1 side of the substrate 2, and the auxiliary gate 6
1 is directed toward a narrow mold space with a thickness d8 on the side opposite to the chip of the substrate 2. These main gate 6 and auxiliary gate 6
When resin is injected from step 1, the narrow mold space having a thickness d2 is filled with resin from each gate while spreading out in a fan shape. Therefore, the main gate 6 and the auxiliary gate 61
The resin that flows into the thin mold space due to the positional relationship is molded in a direction that pushes out the air in that space. In order to synchronize this molding speed with the molding speed of the wide mold space on the chip side of the substrate, a plurality of auxiliary gates communicating with the auxiliary runner 71 may be provided. FIG. 3 shows an embodiment in which the main gate 6 is provided on the side of the substrate 2 opposite to the external lead portion 21. In FIG. If the auxiliary gate 61 is provided on the side of the adjacent mold that is far from the main gate 6, the above-mentioned air extrusion effect will not occur smoothly. However, when the main gate 6 is provided at the center of the side surface of the mold, it may be provided on any adjacent side surface of the mold. 4 and 5, the main gates 6 are all provided on the front side of the main runner 7 when viewed in the resin press-fitting direction shown by the arrow 9, and the main gates are all provided when the auxiliary runner 71 is viewed in the resin press-fitting direction shown by the arrow 9. The auxiliary runners 71 are all provided on the front side of the runners 6 and 6, respectively.
Although the number of molds increases, the injection pressure into each mold space increases and becomes uniform, which has the advantage that a sound resin layer 4 of each semiconductor device can be uniformly molded.

【Effect of the invention】

According to the present invention, in addition to the injection port directed to the thick mold space on the element side of the substrate that supports the semiconductor device, one or more injection ports directed to the thin mold space on the anti-device side are provided to inject thin resin. By arbitrarily setting the molding speed of the layer, it becomes possible to synchronize the molding speed of a thick resin layer. As a result, the resin layers from the front and back of the substrate are prevented from merging, the resin is completely filled, and the resin layer is prevented from containing bubbles and pinholes, and the appearance defects due to the merging of the resins are also eliminated. The present invention is not limited to semiconductor devices in which individual element chips are sealed with resin, but also applies to monolithic IC chips. It can also be effectively applied to the manufacture of semiconductor devices in which hybrid IC substrates are sealed singly or in combination.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, fa) is a plan view after resin molding, (b) is a cross-sectional view of the completed semiconductor device,
FIG. 2 shows a conventional resin-sealed semiconductor device, (a) is a perspective view, (b) is a sectional view, and FIG. 3 is a different embodiment of the present invention, (a) is a plan view after resin molding. 1: Semiconductor chip, 2: Substrate, 21: External lead, 4:
Resin layer, 6: main gate, 61: auxiliary gate, 7: main runner, 71: auxiliary runner. 1N Kaisho 63-99539 (4) Fig. 4 7O~Rokufu = ・-T←=

Claims (1)

[Claims] 1) When supporting a substrate on which a semiconductor element is fixed in a nearly rectangular parallelepiped space of a mold and injecting resin to form a thick resin layer on the element side of the substrate and a thin resin layer on the opposite side of the substrate, A main injection port is provided on one of the mold surfaces perpendicular to the substrate surface, facing the mold space on the element side of the substrate, and a main injection port is provided on the adjacent substrate surface on the side closer to the mold surface than the main injection port. A method for manufacturing a resin-sealed semiconductor device, characterized in that resin is injected through an auxiliary injection port provided on a vertical mold surface facing a mold space on the side opposite to an element of a substrate.