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Method for embedded structures in test chips to facilitate the focusing of CSAM at different metal layers

IP.com Disclosure Number: IPCOM000145860D
Publication Date: 2007-Jan-30
Document File: 2 page(s) / 209K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for embedded structures in test chips to facilitate the focusing of C-mode scanning acoustic microscopy (CSAM) at different metal layers. Benefits include improved functionality and improved performance.

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Method for embedded structures in test chips to facilitate the focusing of CSAM at different metal layers

Disclosed is a method for embedded structures in test chips to facilitate the focusing of C-mode scanning acoustic microscopy (CSAM) at different metal layers. Benefits include improved functionality and improved performance.

Background

      The exact metal layer that the CSAM is focused at is difficult to determine. As a result, the exact location of delamination/damage in the third-dimensional direction (Z-direction) is difficult to observe.

      Conventionally, CSAM can be resolved only between the chip joint layer and the top metal layer of a test chip. No points are referenced at lower metal layers. The location of delamination and interlayer dielectric (ILD) damage in Z-direction is verified by time consuming and labor intensive scanning electron microscope (SEM) cross-sections.

Description

      The disclosed method is metal layer structures at every back-end device layer to improve CSAM image resolution in the Z-direction.

      A CSAM image demonstrates resolution better than 100 microns.  Metal traces are 26-microns wide.

      To implement the disclosed method, etch a layer signature at each metal layer. For example, at metal layer 7, the structure would look like ‘7’. Layer-in-focus enables the...