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EVAPORATION TECHNIQUE TO PREVENT LARGE A12Cu INTERMETALLIC GROWTH

IP.com Disclosure Number: IPCOM000046389D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Agajanian, AH: AUTHOR [+4]

Abstract

A process is described which pre-establishes the size of the Al2Cu intermetallic compounds during the processing of semiconductor wafers. Excessively large Al2Cu intermetallic particles can cause interlevel shorts.

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EVAPORATION TECHNIQUE TO PREVENT LARGE A12Cu INTERMETALLIC GROWTH

A process is described which pre-establishes the size of the Al2Cu intermetallic compounds during the processing of semiconductor wafers. Excessively large Al2Cu intermetallic particles can cause interlevel shorts.

Standard semiconductor processing, including the steps of sintering, quartz deposition, and metal deposition develop temperatures conducive to the growth of large Al2Cu intermetallic compound particles.

To investigate this growth phenomenon wafers were subjected to four consecutive depositons of 3.5 K~ thick layers of Al-Cu with system venting after each deposition. The wafers were then heat treated for 2 hours at 500OEC in an N2 atmosphere to induce particle growth.

Microscopic examination (after sectioning and etching) revealed that the oxide layers produced by the venting effectively constrained the growth of the Al2Cu particles in the vertical direction to the thickness (3.5 K~) of the Al-Cu layer. Horizontal growth was not so inhibited.

For actual device fabrication only a single venting of the system is required to prevent full-film growth of the Al2Cu compounds. Alternatively, in lieu of venting, oxygen or oxygen-rich gases may be introduced into the system to form the oxide film. The two thus-produced Al-Cu metallized stripes separated by the oxide layer are connected in parallel at their terminations by via holes or other terminations. While the oxide layer is indeed resistive,...