Browse Prior Art Database

Method for a substrate interposer in a stacked package

IP.com Disclosure Number: IPCOM000012352D
Publication Date: 2003-Apr-30
Document File: 3 page(s) / 93K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a substrate interposer in a stacked package. Benefits include improved functionality.

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Method for a substrate interposer in a stacked package

Disclosed is a method for a substrate interposer in a stacked package. Benefits include improved functionality.

Background

        � � � � � Conventionally, a single logic die is mounted on silicon using a ball grid array (BGA) package (see Figure 1). A synchronous dynamic random access memory (SDRAM) or other piece of silicon may not be wire-bonded to the bottom substrate due to the package stack configuration. When used in conjunction with a flash die and a logic die, the SDRAM can be stacked and aligned using a stack chip scale package (see Figure 2). However, if a customer asks for additional functionality, such as flash added to the package stack, the die pads are in the wrong orientation relative to the substrate (see Figure 3).

        � � � � � Conventional solutions are price prohibitive and are not easily manufactured. One solution is to use redistribution layer (RDL) technology to reroute the die pads. The other solution is to influence the silicon manufacture to redesign and manufacture new silicon stepping. Both of these solutions may not be feasible.

General description

        � � � � � The disclosed method uses a substrate as an interposer to realign routing in a way more conducive to wire-bonding, improving routing and wire-bonding options within a stacked package.

        � � � � � The key elements of the method include:

•        � � � � Placement of a substrate within the stacked package as a spacer (within the stack) or placed on top of the package stack

•        � � � � Substrate design and routing so that it acts similar to an RDL, enabling a die to be wire-bonded within the package stack to redistribute the final wire-bonding to the bottom substrate

Advantages

        � � � � � The disclosed method provides advantages, including:

•        � � � � Improved functionality due to using a substrate as an interposer to realign routing and improve wire-bonding options for a stacked package

Detailed description

        � � � � � A low-cost substrate to the package stack enables package wire-bonding. The SDRAM bond pattern is rerouted to enable wire-bonding with the bottom substrate that c...