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Reduction of the Brittle Intermetallic Compound Layer Formation Through the Reduction of Halide Content in Polymers

IP.com Disclosure Number: IPCOM000022011D
Publication Date: 2004-Feb-18
Document File: 3 page(s) / 103K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that reduces halides in the polymers used in assembly packaging, resulting in the reduction of the brittle intermetallic layer (IMC) during chip attach reflow and gold wire bonding. Benefits include using the current equipment and direct materials.

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Reduction of the Brittle Intermetallic Compound Layer Formation Through the Reduction of Halide Content in Polymers

Disclosed is a method that reduces halides in the polymers used in assembly packaging, resulting in the reduction of the brittle intermetallic layer (IMC) during chip attach reflow and gold wire bonding. Benefits include using the current equipment and direct materials.

Background

Currently, the presence of halides (e.g. Br- and Cl-) promotes the formation of metal oxides (e.g. Al2O3) that form lamellar structures in the IMC brittle layer, causing separation between the IMC layers. As a result of the separation, Bin 15 (open) failures are usually observed. In addition, failures are further accelerated during reliability stressing (i.e. at high moisture and temperature conditions).

Halide content in the resins is typically controlled during the polymer manufacturing process by using ionic trappers/ionic catchers as an additive (see Figure 1).

General Description

In the disclosed method, the unpurified epoxy resin is purged into an ion exchanger tower that consists of small beads with highly active surfaces coated with hydroxyls (see Figure 2). During the process, halides from the resins are exchanged with hydroxyl groups from the beads (see Figure 3). After the exchange, the halides remain in the ion exchange tower until all the hydroxyls are consumed. The rate of the ion exchange reaction can be accelerated with an increase in temperature. A heating jacket is u...