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Mold Cap Back-Grind for Expose Die Backside

IP.com Disclosure Number: IPCOM000008483D
Publication Date: 2002-Jun-17
Document File: 3 page(s) / 53K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses a back-grinding process to remove excess mold compound from the mold cap; this results in an exposed die backside which enables thermal dissipation.

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Mold Cap Back-Grind for Expose Die Backside

Disclosed is a method that uses a back-grinding process to remove excess mold compound from the mold cap; this results in an exposed die backside which enables thermal dissipation.

Background

Molding an exposed die backside of a Flip-Chip Matrix Molded Array Package (FC-MMAP) requires the die backside in the matrix to be as level as possible; however, bump height can alter the final die height from the substrate surface (see Figure 1).

Based on current bump height specifications, the variation between the die backside surfaces may be greater that what is tolerable by the current film-type or floating plunger exposed die molding technology. In the current technology, this height may be compensated by using a floating plunger and/or polymer film to protected the die backside during molding (see Figure 2). Both technologies depends on the protection of the die backside during the molding process.

General Description

The disclosed method involves back-grinding the mold cap of the package after molding. The package is first over-molded, then the mold cap is ground down to expose the die backside (see Figure 3 and 4).

Advantages

The disclosed method is a very robust exposed die backside molding process that can accommodate different wafer thickness, tilt, and under-fill gap height. The disclosed method

also enables thermal dissipation.

Figure 1. Current specification allows for +/- 0.9 mils difference in the solder bump height.

Figure 2....