Browse Prior Art Database

Dynamic Temperature Sensor

IP.com Disclosure Number: IPCOM000093895D
Original Publication Date: 1966-Mar-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Piper, H: AUTHOR

Abstract

In the processing of semiconductor device s through various steps of heating and diffusion, the time -temperature cycle of the furnaces used must be closely controlled. The dynamic response of a furnace, i.e., the time required for the furnace to respond to a given load and come to an equilibrium temperature, is most critical. This apparatus allows the temperature within a furnace to be accurately monitored on a production line basis. The apparatus automatically initiates either under -temperature or over -temperature indicator s if the furnace does not respond properly.

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Dynamic Temperature Sensor

In the processing of semiconductor device s through various steps of heating and diffusion, the time -temperature cycle of the furnaces used must be closely controlled. The dynamic response of a furnace, i.e., the time required for the furnace to respond to a given load and come to an equilibrium temperature, is most critical. This apparatus allows the temperature within a furnace to be accurately monitored on a production line basis. The apparatus automatically initiates either under -temperature or over -temperature indicator s if the furnace does not respond properly.

When semiconductor device 10 is inserted into furnace 12, the temperature within furnace 12 abruptly decreases until device 10 is brought up to temperature. This decrease in temperature is sensed by thermocouple 14 and sent to DC reflecting galvanometer 16. As is normal in such galvanometers, light beam 18 is directed at translucent window 20 and provides a visible indication of the potential applied to the galvanometer. In this case, galvanometer 16 is modified by the placement of two solar cells on window 20. Solar cell 22 is placed at the low end of the scale and solar cell 24 at the high end of the scale. Each cell exhibits a high resistance until it is illuminated by beam 18, at which time its resistance decreases. Cell 22 controls the energization of timer 34. Cell 24 controls overshoot indicator 36.

So long as no load is introduced into furnace 12, beam 18 is cen...