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A Transfer Mold Compound Sheet with Embedded Solder Paste

IP.com Disclosure Number: IPCOM000126993D
Publication Date: 2005-Aug-16
Document File: 5 page(s) / 457K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a square-shaped transfer mold compound (TMC) sheet (for use as an underfill sheet) with an embedded solder paste. Benefits include simplifying the connection between the die and substrate, and eliminating delamination issues.

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A Transfer Mold Compound Sheet with Embedded Solder Paste

Disclosed is a method for a square-shaped transfer mold compound (TMC) sheet (for use as an underfill sheet) with an embedded solder paste. Benefits include simplifying the connection between the die and substrate, and eliminating delamination issues.

Background

Currently, delamination occurs on the contact surface between the underfill and the over mold, during post reliability testing of the Flip Chip Matrix Molded Array Package (FCMMAP). This is caused by an CTE or material composition mismatch between the underfill and over mold materials (see Figure 1).

There is currently no adequate solution for delamination. To minimize this issue, an underfill and over mold are chosen that have a similar CTE and chemical composition.

General Description

Currently, the flip chip package interconnection between the die and substrate has a complicated structure. Bumps are formed on both the die and substrate sides, then the die is flipped and placed onto the substrate. The conductive interconnection is made via the reflow process. Afterward, the interconnect is encapsulated within the underfill.

In the disclosed method, the interconnect structure between the die and substrate is simplified, and the assembly process is conducted by processing the

CAM

and underfill encapsulation simultaneously. The square shape of the TMC sheet and an example of the final package are shown in Figure 2. This invention consists of two elements:

1.      Forming the square shape TMC sheet. The sheet is formed with through-holes by using a  transfer mold compound powder and compress without chemical reaction. Figure 3 shows the typical transfer mold compound manufacturing process...