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Method for tape automated bonding stacked chip scale packaging

IP.com Disclosure Number: IPCOM000007943D
Publication Date: 2002-May-07
Document File: 3 page(s) / 56K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for tape automated boding stacked chip scale packaging (TAB-stacked CSP). Benefits include improved throughput, improved test environment, and reduction of defects.

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Method for tape automated bonding stacked chip scale packaging

Disclosed is a method for tape automated boding stacked chip scale packaging (TAB-stacked CSP). Benefits include improved throughput, improved test environment, and reduction of defects.

Background

              The thinnest package possible is required for stacking chip scale packaging (CSP). This requirement is not met by the conventional approach. It limits the number of die stacks for a given package height. A number of sequential process steps are affected.

              For example, a stack of five die-attach layers requires five spacers, five sequential die attach steps, and three sequential wire-bonding steps. These spacers and die attach layers increase the overall package thickness. The first die is attached to the substrate and then wire bonded. Because of the high loops and fragile nature of bonded wires, a spacer is die attached to the first die to provide clearance and avoid damage of the wires. The second die is then die attached and then wire bonded. This process is then repeated until all of the die are attached and bonded.

General description

              The disclosed method interconnects vertically stacked dice (including dice of the same size) using tape automated bonding (TAB) and wire bonding as methods of interconnection. The method enables the reduction of the overall package height by eliminating the need for spacers between die and by the inherent thinness of TAB. It enables interconnection from die to package as well as from die to die.

              The key elements of the method are:

§         TAB tape with wire bond pads and a rigid enough insulation ring to support wire bonding

§         TAB bonding to die

Advantages

      The thinnest package possible is achieved by utilizing tape automated bonding (TAB) as the interconnect method, directly to the die. The requirement for spacers (which increases package height) is eliminated. Sequential and multiple die attach and wire bond steps can be reduced to one of each step thus simplifying the assembly process. Interconnect from die to die or from die to package is made possible, providing much more flexibility in the interconnection scheme. Testing of the TAB bonded die is also enabled so that known good die are as...