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Method for molding thin microprocessor MMAP packages for flip-chip dies

IP.com Disclosure Number: IPCOM000010574D
Publication Date: 2002-Dec-18
Document File: 2 page(s) / 72K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for molding thin microprocessor molded matrix array packages (MMAPs) for flip-chip dies. Benefits include improved reliability.

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Method for molding thin microprocessor MMAP packages for flip-chip dies

Disclosed is a method for molding thin microprocessor molded matrix array packages (MMAPs) for flip-chip dies. Benefits include improved reliability.

Background

      Voids and defects form in the package during the transfer molding process. Especially in the case where flip-chips are packaged, the risk of air and bubble entrapment is high in the substrate-die interface (such as the die gap area) when molding compound is used as underfill for MMAP substrates (see Figure 1). The voids are formed mainly because of nonuniform flow fronts inside the mold cavity. The flow fronts meet form knit lines and trap air bubbles.

      Conventionally, this problem is addressed using the following approaches:

•             Venting the substrate by introducing a mechanical hole through the substrate body, using valuable routing silicon surface area

•             Vacuum-assisted molding tooling, which has proven to be costly and requires frequent preventative maintenance (PM)

     

Description

      The disclosed method is molding thin microprocessor MMAP packages for flip-chip dies.

The method includes a mold design that has staggered die cavities for improving mold compound flow and under-die gap filling for flip-chip assemblies constructed by MMAP packaging techniques (see Figure 2). The disclosed method improves thin-package molding.

      To obtain void/defect free molding, a uniform flow front must ...