dmc2005,
This is a difficult question to answer with any certainty. The HK5467 has an outline area of 3" X 5" which presumably is larger than the silicon wafer that needs to be heated to 65°C. A flexible heater that is going to be sandwiched to the wafer would likely need to have a compliant backing of some type (closed cell foam maybe) to hold the heater uniformly against the wafer during warming. On the subject of uniformity, the catalog heater design likely has lead terminations within the 3" X 5" area, leaving a portion of the surface inactive as a heater. So many silicon wafer heating applications require very tight temperature uniformity, which leads to the conclusion to use a custom design heater with profiling of the wattage to match the heat losses of the wafer.
One thing that can be stated with a fair degree of certainty is that the heater will not likely warm to 65°C in 5 minutes with a 12 volt source and 77.7 ohm resistance. That translates to about 2 watts total and about 0.13 watts/square inch of surface area. Without any heat load applied (i.e. hanging in still air), this heater would not likely rise to 65°C. Add any heat losses from the wafer and the problem is worse. It would be best to get a rough idea of the wattage requirement by using a heater with a variable voltage supply and keep upping the voltage until tthermal response is achieved.
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