Encapsulation structure and method for forming same

Abstract

The present invention relates to a packaging structure and a forming method thereof. The packaging structure includes: a substrate, the substrate has a first surface and a second surface opposite to each other, and the first surface of the substrate has at least one elongated concave Groove, the two ends of the groove extend to the edge of the substrate, which is an open port, the depth of the groove is smaller than the thickness of the substrate; the chip, the chip is flip-chip fixed on the first substrate of the substrate through welding bumps On the surface, an electrical connection is formed between the solder bump and the substrate, the groove is at least partially located within the projection of the chip on the substrate; an underfill layer fills the chip and the substrate a gap between the first surfaces of the substrate; a plastic encapsulation layer covering the underfill layer and wrapping the chip. The encapsulation structure can effectively discharge internal gas during the injection molding process without affecting the connection area on the back of the substrate.

Description

technical field [0001] The invention relates to the field of chip packaging, in particular to a packaging structure and a forming method thereof. Background technique [0002] After the chip is packaged, it needs to be packaged by injection molding to protect the chip. [0003] For a chip packaged by a flip chip process (Flip chip), the chip and the substrate are connected to the circuit on the substrate through solder balls. During the plastic encapsulation process, it is necessary to wrap the entire chip with a plastic encapsulant to fill the gap between the chip and the substrate. Since the chip and the substrate are directly connected by solder balls or other solder bumps, the gap is small, and the distance between the connection points is also small. Therefore, the air is not easy to discharge when the plastic encapsulant is filled, and it is easy to be between the chip and the substrate. Bubbles are generated in the plastic encapsulant, which affects the stability of...

AI Technical Summary

Problems solved by technology

In order to have a better exhaust effect, multiple air holes are usually formed on the substrate, but since most of the area on the substrate is used to connect with the chip, the area where the air holes can be formed is small and a large number of air holes are formed , so that the size of each air hole is smaller. Although the number of air holes increases, the exhaust position can be increased, but due to the small air hole size, it will be easily blocked by the plastic sealant, and the improvement of the exhaust effect is limited.

And because the pores penetrate the substrate, it will occupy the area used to form the circuit in the substrate, resulting in the limitation of the circuit design in the substrate, especially the number and position distribution of solder balls formed on the back of the substrate will be greatly affected, resulting in The connection area on the back is reduced

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