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An approach to thin MMAP technology using bumpless build up

IP.com Disclosure Number: IPCOM000008385D
Publication Date: 2002-Jun-11
Document File: 4 page(s) / 103K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is an approach to thin mobility management application protocol (MMAP) technology using a bumpless build-up layer (BBUL) process. Benefits include improved functionality and improved reliability.

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An approach to thin MMAP technology using bumpless build up

Disclosed is an approach to thin mobility management application protocol (MMAP) technology using a bumpless build-up layer (BBUL) process. Benefits include improved functionality and improved reliability.

Background

      The trend in non-CPU packages is towards thinner packages with multiple dies stacked on a single substrate form. This goal is conventionally achieved by reducing overall package height, including substrate thickness, die thickness, and bond-line thickness on die attaches and mold caps (see Figure 1). However, thin packages with stacked dies causes stress/warpage problems, leading to delamination of materials at interfaces and potentially poor performance. In addition, the trend to lead-free interconnects increases reflow temperatures to 260°C, adding package stress.

Description

              The disclosed method is a design for thin, multi-stacked packages. This approach extends the BBUL process (see Figure 2). The first die is embedded into the substrate. The second and subsequent dice are stacked using a conventional die attach process, followed by wire bonding and overmolding (see Figures 3, 4, and 5). The result is a thin next-generation package. This approach alleviates the underfilling of the mold compound, as no C4 interconnections exist. The bumps are built directly on the die, using conventional build-up technology. The thickness of the stacked packages is significantly decreased by embedding the first die i...