Browse Prior Art Database

Vacuum Venting-Evaporator

IP.com Disclosure Number: IPCOM000036648D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Cosgrove, JF: AUTHOR [+2]

Abstract

A simple, low cost, metal-filtering element is used to effectively control inert gas flow during back-fill of a metal evaporator system so as to eliminate undesired turbulence and movement of contaminants to wafers in the system.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 2

Vacuum Venting-Evaporator

A simple, low cost, metal-filtering element is used to effectively control inert gas flow during back-fill of a metal evaporator system so as to eliminate undesired turbulence and movement of contaminants to wafers in the system.

The figure illustrates a typical metal evaporation system. Both an existing, commonly employed, micro valve 1 and the here disclosed SST vent diffuser 2, are used to achieve a reduction in particulate contamination of wafers during the back-fill operation. Other elements in the system are the vacuum chamber 3, the wafer dome 4, the silicon wafer(s) 5, the metal evaporation source 6, a vacuum isolation valve 7, the evaporation (sputter) source area 8 and the vacuum pump assembly 9.

Normal manufacturing procedures call for venting the vacuum chamber from 1 x 10-6 Torr to atmosphere with a controlled flow of an inert gas, e.g., nitrogen. This gas must be bled into the process chamber 3 at a rate consistent with both an acceptable wafer yield and high wafer thru-put.

Current methods for minimizing the unwanted displacement of contaminants make use of a microvalve 1, as shown to the right of the figure, to achieve acceptable control of the back-fill gas introduced to the chamber. This procedure, however, has been determined to add as much as 20 to 25% to processing times, i.e., N15-minute increase in vent time.

The disclosed installation of the SST porous, sintered metal filtering element 2 (Leybold-Harqeus P.N. 1836...