Browse Prior Art Database

Edge Coverage Measurement

IP.com Disclosure Number: IPCOM000089907D
Original Publication Date: 1968-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Pileur, P: AUTHOR

Abstract

This method accurately measures the thickness of a layer deposited on a conductor configuration formed on a surface, particularly on the top surface of a passivated semiconductor wafer. After the first level of metallization, quartz layer 5 is deposited. It is required to have an exact measurement of the thickness of layer 5 at the edge of the metallic lands, because this is where the quartz deposition is the thinnest.

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Edge Coverage Measurement

This method accurately measures the thickness of a layer deposited on a conductor configuration formed on a surface, particularly on the top surface of a passivated semiconductor wafer. After the first level of metallization, quartz layer 5 is deposited. It is required to have an exact measurement of the thickness of layer 5 at the edge of the metallic lands, because this is where the quartz deposition is the thinnest.

A test wafer which has been submitted to the same process steps is prepared with a special pattern of equally spaced parallel conducting lands 1...4, etc. Next, a progressive chemical etching is conducted in a transverse direction on an unmasked portion of the test wafer surface. Due to the progressive etching, quartz surface 6 becomes surface 7.

Next, from right to left, surface 7 is tested to determine which is the last conducting land that is not completely covered by the quartz layer. If the last land is land number 3, the thickness X of the quartz on the edge of the land is equal to the distance between the original quartz surface 6 and the actual one 7 on this edge. This measurement can be carried out by infrared interferometry.

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