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Method for a flip-chip bump pull test method using a soldered copper wire

IP.com Disclosure Number: IPCOM000006276D
Publication Date: 2001-Dec-19
Document File: 3 page(s) / 1K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a flip-chip bump pull-test method using a soldered copper wire. Benefits include evaluation of bump integrity without the use of a dedicated tool.

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Method for a flip-chip bump pull test method using a soldered copper wire

Disclosed is a method for a flip-chip bump pull-test method using a soldered copper wire. Benefits include evaluation of bump integrity without the use of a dedicated tool.

Background

No conventional method exists for determining the adhesion strength of flip-chip bumps or for determining the weakest interface between the bump and underlying layers under tensile/peeling stresses.

The bump shear test is conventionally used industry wide (see Figure 1). However, this test has serious limitations, including:

·        The test applies a shear stress on the bumps and not a peeling or tensile stress.

·        The shear test usually results in cohesive failure within the bump region because the bump is very soft.

·        Failure mode is very sensitive to the test set up parameters such as shear tool stand off distance.

General description

The disclosed method determines the adhesion strength of flip-chip bumps on the device or package surface. The method involves soldering a copper wire on the bump or bumps and using a pull test to determine the adhesion strength. The method can be used to identify the adhesion strength of the weakest interface in the flip-chip bump attach region.

 The key elements of the method include:

·        The flip-chip bump can be made with different compositions such as copper, lead/tin solders or lead free solders.

·        Copper wire or other metallic wires is attached to the flip-chip bumps with a solder that forms a strong solid-state bond between the wire and the bump.

·        A pull or peel ...