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Junction Delineation by Plasma Etching

IP.com Disclosure Number: IPCOM000052505D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 3 page(s) / 156K

Publishing Venue

IBM

Related People

Blake, HH: AUTHOR [+2]

Abstract

With the semiconductor industry moving to shrink geometries and also making junctions that are extremely shallow, conventional techniques, such as chemical etching do not delineate diffused or implanted junctions for precise measurements. The technique and procedure outlined in this article successfully delineates and measures a junction only 3000 angstroms deep. In addition, a SI(3)N(4) layer 1600 angstroms in thickness, a SiO(2) laye angstroms in thickness and a TiW layer 1600 angstroms in thickness can also be d with a single plasma etch. The following details the procedure which can be used on both bipolar and memory devices.

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Junction Delineation by Plasma Etching

With the semiconductor industry moving to shrink geometries and also making junctions that are extremely shallow, conventional techniques, such as chemical etching do not delineate diffused or implanted junctions for precise measurements. The technique and procedure outlined in this article successfully delineates and measures a junction only 3000 angstroms deep. In addition, a SI(3)N(4) layer 1600 angstroms in thickness, a SiO(2) laye angstroms in thickness and a TiW layer 1600 angstroms in thickness can also be d with a single plasma etch. The following details the procedure which can be used on both bipolar and memory devices.

Plasma etching with the Tegal Plasmaline etcher can be employed on sectioned 1-micron product. In the preparation of samples for SEM (Scanning Electron Microscopy) examination, 90 degrees sections are prepared on a glass wheel into emitter, collector and base contacts. The chip contains a TiW layer which is used for low barrier Schottky diodes.

With the chip still on the stainless steel block, it is placed within the plasma chamber. A gas of 100% oxygen with 2.5 psi, 1 torr pressure average RF power of 200 watts and vacuum pumping speed of 160 liters/minute can be utilized. The above conditions are used to clean the Si surfaces of all organic contaminants to make the surface conductive to etching.

In order to obtain Si, Si(3)N(4), SiO(2) and metal etching, the gas mixture is changed to 10% oxygen an...