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Surface Temperature Monitor for Thin Film Processing Equipment

IP.com Disclosure Number: IPCOM000087853D
Original Publication Date: 1977-Mar-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR [+4]

Abstract

For usual thin-film processing, the monitoring of wafer surface temperature is essential for device quality control. However, the use of ordinary temperature sensing devices, such as thermocouples, is often impossible since it is difficult to use these in processes such as sputtering.

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Surface Temperature Monitor for Thin Film Processing Equipment

For usual thin-film processing, the monitoring of wafer surface temperature is essential for device quality control. However, the use of ordinary temperature sensing devices, such as thermocouples, is often impossible since it is difficult to use these in processes such as sputtering.

In order to overcome this, it is proposed to use monitor wafers which are subjected to the actual processing environment as a measure of the thin-film wafer temperature. The surface changes occurring on the monitor wafers are known to occur at set temperatures, and therefore provide an indication of temperature at the wafer surface. For example, a number of solid-state reactions are useful for this purpose, such as ' the formation of eutectic alloys, melting of binary compounds or alloys and discoloration of surface film due to diffusion of underlying materials.

The following table lists a number of material systems which can be used to provide the monitor wafers, together with the temperature set points and solid-state reactions which are monitored. Material Temperature Solid State Reactions System Set Point (degrees C) to be monitored Au/Si 370 Formation of Au(.75)Si(.25) eutectic (The melt has a silver color)

Al/Si 577 Formation of AlSi eutectic Ag/Si 830 Formation of AgSi eutectic Au/Ge 356 Formation of Au(.73)Ge(.27) eutectic Cu/Si <200 Discoloration of Cu due to CuSi reaction

Bi-Sn alloys 139 to 232 Melting of BiSn...