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Method for a substrate for stacked die and a die-stacking process

IP.com Disclosure Number: IPCOM000010059D
Publication Date: 2002-Oct-16
Document File: 3 page(s) / 137K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a substrate for stacked die and a die-stacking process. Benefits include improved functionality and improved performance.

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Method for a substrate for stacked die and a die-stacking process

 

Disclosed is a method for a substrate for stacked die and a die-stacking process. Benefits include improved functionality and improved performance.

Background

      Package thickness is a factor that conventionally limits the stacking of dies in a package. Wire loop height and mold cap height add to the overall thickness of a stack package.

      The long loop length of wirebond stacking degrades the performance of stack packages.

 

              Conventional stacked package solutions include the following (see Figure 1):

•             Wire-bond stack die packages

•             Wire-bond flip-chip mixed stacks

•             Folded stacks

      Package thickness is conventionally addressed by the following methods:

•             Thinner die

•             Thinner substrate

•             Low loop wirebonding process

•             Thinner moldcap

      Dies are conventionally determined to be good by testing the package after stacking. Substandard dies result in yield loss because the entire stacked package must be scrapped.

General description

              The disclosed method uses a multilayer substrate design that has a cavity of various sizes at each layer (see Figure 2, cross section). This method is an all flip-chip, low thickness stack architecture that utilizes a multitier cavity substrate. The cavities are open in the center of each layer of the substrate. The cavities are of different sizes with the smallest cavity in the bottom. The die at the lowest level is flip-chip bonded to the bottom cavity. The second die is flip-chip bonded to the shelf of the next layer. The third die is flip-chip bonded to the shelf of the next layer, and so on.

              The key elements of the disclosed method include:

•             Multilayered substrate with cavities of various sizes at each substrate layer

•             Multitier organic or ceramic substrate

Adv...