Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Method of Measuring C4 Gap in a Flip Chip Package Using an Ordinary CMM

IP.com Disclosure Number: IPCOM000245420D
Publication Date: 2016-Mar-08
Document File: 1 page(s) / 23K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to use a Coordinate Measurement Machine (CMM) to accurately measure the C4 gap between the die and the laminate of a flip-chip module.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 54% of the total text.

Page 01 of 1

Method of Measuring C4 Gap in a Flip Chip Package Using an Ordinary CMM

A method is needed for accurately measuring the C4 gap between the die and the laminate of a flip-chip module.

One known solution is a Failure Analysis (FA) cross section. However, FA is a destructive procedure to the sample being measured and has a lengthy turnaround time to complete. Another option is to manually perform the measurement using a micrometer; however, this method is slow, tedious, and inaccurate.

The novel solution is to use a Coordinate Measurement Machine (CMM) to measure the backside of the laminate, the front side of the laminate, and the top side of the joined die. Using known values for the die thickness, one can calculate the C4 gap. Performing this in multiple locations generates a map of C4 gap height.

To implement this solution in a preferred embodiment:

1. Measure the thickness of the module die/chip for use in calculations later. If the nominal die thickness is used, the resulting thickness variation map is still valid, but the absolute value may not be accurate.

2. Configure the CMM with a five (5)-pointed cross probe, capable of measuring X, Y, and Z values on multiple sides of the module without having to change measurement tools

3. Mount the module in a fixture that permits measurement on all sides without requiring re-mounting during the measurement sequence. In this case, the module is mounted on its side to permit full access to top and bottom surfaces. (La...