A practical method for low temperature rapid thermal process (RTP) monitoring, ranging from 400°C to 650°C, has been demonstrated. Conventional RTP monitoring methods such as implant wafer annealing or rapid thermal oxidation (RTO) can only be used for monitoring the temperature range over 650°C. However, with the physical characteristics of cobalt silicide (CoSix) and by an indirect parallel monitoring method, we are able to monitor the lower RTP processing temperature at which the CoSix phase transforms. Depending on the sheet resistance (RS) of CoSix after RTP thermal treatment, we can precisely indicate how much the RTP processing temperature shifts from its target value. Furthermore, the non-uniformity of RS is also an index to check the stability of RTP system working at low temperature. Within the phase transformation temperature region, the RS non-uniformity raises suddenly; otherwise, the RS shows a very good uniformity.
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