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Dual Cavity Folded Flex with Discrete Enabling Option

IP.com Disclosure Number: IPCOM000074587D
Publication Date: 2005-Feb-23
Document File: 3 page(s) / 192K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that enables a dual discrete package or FS-CSP package to be used on the same substrate design, depending on customer requirements. Benefits include improving marketing opportunities and manufacturing flexibility.

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Dual Cavity Folded Flex with Discrete Enabling Option

Disclosed is a method that enables a dual discrete package or FS-CSP package to be used on the same substrate design, depending on customer requirements. Benefits include improving marketing opportunities and manufacturing flexibility.

Background

Currently, there is a need to improve manufacturing flexibility in a logic + memory die stack package.  Once memory and logic are “coupled” together in a stacked package, there is no ability to separate the two and sell them as discrete packages. There are several approaches used today to add memory + logic to a package:

1.      For FS-CSP package stacks, a polyamide flex substrate used in the bottom package (folded flex) and the flash package stacked on top is a UT-Flex package using the same type of substrate (see Figure 1). 

2.      In another version of FS-CSP,  the same folded flex substrate is used to house both the logic + memory die (see Figure 2).

3.      The most common method is a SCSP package configuration (see Figure 3)

General Description

The disclosed method enables a dual discrete package or FS-CSP package, using the same substrate design (depending on customer requirements). The key elements of the disclosed method are:  

§         Using a folded flex substrate design that uses a thin multi-layer polyimide based substrate

§         Routing a folded flex substrate, so that the top fold can work as a stand alone discrete package if the fold is cut

§         Cutting a fold region to allow dis...