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Method for an optical technique to evaluate contact/trench fill quality

IP.com Disclosure Number: IPCOM000029140D
Publication Date: 2004-Jun-16
Document File: 3 page(s) / 110K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an optical technique to evaluate contact/trench fill quality. Benefits include improved functionality, improved throughput, and improved eased of implementation.

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Method for an optical technique to evaluate contact/trench fill quality

Disclosed is a method for an optical technique to evaluate contact/trench fill quality. Benefits include improved functionality, improved throughput, and improved eased of implementation.

Background

      The poor filling of contacts with conducting material causes open circuits or high resistance in integrated circuits ICs). Detection of the poor contact fill is required to improve reliability. 

      The conventional solution to detect poor filling is taking end-of-line device yield measurements. This procedure is  expensive and slow. It is not suited for quick-turn experiments on process modifications or changes to improve fill performance.

General description

      The disclosed method is an optical technique to estimate the quality of contact plug fill.

A wafer with filled contact plugs is chemically etched in a characteristic pattern where the contact or trench fill is poor. The dielectric layer and the conducting layer filling the contact are removed through a stripping process. The locations where the poor fill has been removed can easily be detected through standard optical or scanning electron microscope (SEM) defect inspection equipment.

Advantages

              The disclosed method provides advantages, including:

•             Improved functionality due to unambiguously and quantitatively estimating the quality of contact plug fill

•             Improved throughput due to improving the time required to obtain quantitative data by using large sample areas

•             Improved throughput due to using a short process flow to create the substrate used for the test

•             Improved ease of implementation due to using standard well-known optical or SEM-based defect techniques

Detailed descr...