Positioning method for semiconductor chip suspending arm encapsulation

Abstract

A positioning method for cantilever packaging of semiconductor chips. Aiming at the unilateral design of pins, the pins or the frame edge of the lead frame are clamped by the clamping pressure of the upper and lower molds, so that the bare chip components are in a cantilever support state in the mold cavity, and the Positioning in the X and Y directions is characterized in that the positioning in the Z direction is as follows: in the upper mold cavity or the lower mold cavity, a positioning pin for controlling the distance is set in the Z direction for the bare chip or lead frame, and at the same time on the suspended lead frame A guide slope is provided, the guide slope is inclined toward the positioning pin side, and the injection inlet of the packaging material is directed to the guide slope. When the molten packaging material is poured through the injection inlet pressure, a lateral component force is generated on the guide slope, pushing the bare chip assembly on the guide slope. In the Z direction, it is attached to the end face of the positioning pin, so as to realize the positioning in the Z direction. The method is simple, reliable, low in cost and ingenious in conception, and solves the difficult problem of positioning the bare chip component supported by the cantilever in the Z direction of the mold cavity.

Description

technical field [0001] The invention relates to the technical field of packaging of semiconductor devices, in particular to a positioning method for cantilever packaging of semiconductor chips. Background technique [0002] The packaging of semiconductor electronic components not only plays the role of connecting the internal semiconductor chip with the external electrical components, but also plays the role of mechanical protection and environmental sealing. Therefore, the quality of packaging is closely related to the overall performance of semiconductor devices. [0003] There are various packaging methods for semiconductor devices, among which there is a packaging method suitable for ordinary semiconductor devices, that is, injection molding. This method usually uses epoxy resin as the packaging material, and forms a cavity through pressure clamping of the upper and lower molds, while the bare chip component is positioned in the center of the cavity, and then pressure-i...

AI Technical Summary

Problems solved by technology

It is conceivable that if the bare chip assembly has front-to-back or left-right bidirectional pins, it is easy for the mold to press the pins from both ends to position the bare chip in the X, Y, and Z directions of the cavity; if a bare chip assembly has only one The positioning of pins in one direction on the side will be in a cantilever state in the cavity. In this state, the positioning of the bare chip component relative to the cavity space in the X and Y directions can be controlled by the cooperation of the pins and the mold, but the z direction The positioning of the arm becomes difficult to control as the arm length increases

Especially for thin or flat semiconductor devices, not only the positioning in the z direction is very necessary but also very difficult to control

Because, if the position of a bare chip component in the z direction in the cavity cannot be fixed, the distance from the chip to the surface of the body in the Z direction cannot be controlled. If the distance from the surface is too close, the insulation and voltage resistance of the device will be poor, which will directly affect the product quality. and pass rate

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