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CATHODE COUPLING ALL MODE PLASMA ETCHER

IP.com Disclosure Number: IPCOM000005688D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2001-Oct-26
Document File: 1 page(s) / 49K

Publishing Venue

Motorola

Related People

Shinichi Nakajima: AUTHOR

Abstract

In PPE. plasma etching an R.F. supply is connected to one electrode and the wafer is placed on a second, grounded electrode. Anisotropic etching is very difficult to realize in this device. P.P.E. etching is best suited to isotropic etching with very little damage caused by ion etching.

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MOTOROLA Technical Developments Volume 7 October 1987

CATHODE COUPLING ALL MODE PLASMA ETCHER

by Shinichi Nakajima

   In PPE. plasma etching an R.F. supply is connected to one electrode and the wafer is placed on a second, grounded electrode. Anisotropic etching is very difficult to realize in this device. P.P.E. etching is best suited to isotropic etching with very little damage caused by ion etching.

   In R.I.E. etching the wafer is mounted on the electrode having the R.F. supply connected thereto. A negative self-bias voltage is developed with the application of the R.F. voltage which accelerates the positive ions to vertically enter the wafer and perform the etching. Therefore, anisotropic etching can be done easily but the accelerated ions damage the wafer.

   The present plasma etcher is basically the R.I.E. configuration with one end of an R.F. choke coil 10 con- nected to the wafer bearing electrode and the other end connected through a capacitor 11 to ground and to a contact 12 of an SPST switch 13, the other contact 14 of which is connected to ground. When switch 13 is open the self-bias is generated and the device operates in the R.I.E. mode. When switch 13 is closed a D.C. path to ground is completed through the R.F. filter and the self-bias becomes 0 v. so that the device operates in the PPE. mode. Because the switching can be performed without turning of the R.F supply, the modes are switched instantly and easy control of the etching profile is possible.

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