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In Process Inspection With E Beam

IP.com Disclosure Number: IPCOM000052518D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Moore, RD: AUTHOR

Abstract

Today, in-process inspection of semiconductor wafers is accomplished, for the most part, with optical inspection by skilled operators. Using a microscope, the operator scans the chip sites of a selected test wafer to determine its acceptability. Unacceptable conditions include: 1. High deflect level. 2. Missing process steps. 3. Gross dimensional inaccuracies.

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In Process Inspection With E Beam

Today, in-process inspection of semiconductor wafers is accomplished, for the most part, with optical inspection by skilled operators. Using a microscope, the operator scans the chip sites of a selected test wafer to determine its acceptability. Unacceptable conditions include: 1. High deflect level.

2. Missing process steps.

3. Gross dimensional inaccuracies.

It is proposed to use a scanning E-beam system to inspect the chip site and compare it to a known "good" chip.

The procedure for this inspection is as follows:
1. A good chip is identified manually at a process level of

interest.
2. The good chip is placed in the E-beam system, and a

registration operation is performed.
3. The good chip is scanned in a raster mode, and the

backscattered signal is measured and recorded as a function

of the scan field.
4. Additional good chips are scanned and recorded, and an

envelope of acceptable signal levels as a function of scan

field is established.
5. Once the acceptable backscatter signal boundaries are

established for a given process level, it is possible to

measure test chips and compare the backscatter signals of the

test chip to the acceptable signals. When the test chip

signals exceed the acceptable signal levels, there is probably

an unacceptable defect at that location. That chip and/or

wafer would be rejected and manually inspected to determine

cause of failure. The E-beam inspection tool allows for the

print-out of the locati...