A heated process is used to heat a semiconductor wafer operates with first-order dynamics, that is, the

where K has units [?C/Kw] and ? has units [minutes]. The process is at steady state when an engineer changes the power input stepwise from 1 to 1.5 Kw. She notes the following:

(i) The process temperature initially is 80?C.

(ii) Four minutes after changing the power input, the temperature is 230 ?C.

(iii) Thirty minutes later the temperature is 280 ?C.

(a) What are K and tin the process transfer function?

(b) If at another time the engineer changes the power input linearly at a rate of 0.5kW/min, what can you say about the maximum rate of change of process temperature: When will it occur? How large will it be?

Transcribed Image Text:

T(s) P'(s) 1s + 1 к