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Browse Prior Art Database

Chrome Copper Chrome Metallization

IP.com Disclosure Number: IPCOM000073397D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Enichen, WA: AUTHOR [+5]

Abstract

Uniform contouring of the metallization layer over contact holes in semiconductor devices is necessary to provide the proper current carrying capacity and to prevent undesired interaction between overlying metallurgy such as lead-tin solder pads with underlying metallurgy containing a high conductivity metal. An overcoating such as chromium is used to prevent interaction between lead-tin and copper or silver. Failure to contour the topology involved usually results in incomplete shielding of the high conductivity metal. The method disclosed provides full coverage of the copper or silver by introducing an atmosphere of argon or any other heavy inert gas during the evaporation of chromium. The heavy inert gas molecules serve to scatter the evaporant. A description of the technique follows.

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Chrome Copper Chrome Metallization

Uniform contouring of the metallization layer over contact holes in semiconductor devices is necessary to provide the proper current carrying capacity and to prevent undesired interaction between overlying metallurgy such as lead-tin solder pads with underlying metallurgy containing a high conductivity metal. An overcoating such as chromium is used to prevent interaction between lead-tin and copper or silver. Failure to contour the topology involved usually results in incomplete shielding of the high conductivity metal. The method disclosed provides full coverage of the copper or silver by introducing an atmosphere of argon or any other heavy inert gas during the evaporation of chromium. The heavy inert gas molecules serve to scatter the evaporant. A description of the technique follows.

To deposit the metallization, an evaporator is pumped down to 3 x 10/-6/ Torr and chromium is deposited to a thickness of about 500 to 1500 angstroms. A second level metallization or copper is phased into the first metallization and the copper is evaporated to a thickness of about 2 microns. The top level metallization or chromium is obtained by backfilling the evaporator with argon or any other heavy inert gas to a pressure of 1 x 10/-1/ to 10/-4/ Torr as measured by an ionization gauge. The top level chromium is evaporated to a thickness of 1500 angstroms to complete the metallization.

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