Temperature measuring device using oscillating frequency signals
This invention provides a wafer-type temperature sensor capable of eliminating the need for an A/D converter, adapting itself to automation and improving the heat resistance to measure temperature distribution of the upper surface of a wafer, a temperature measuring device using the sensor, a thermal processor having a temperature measurement function and a temperature measurement method. The wafer-type temperature sensor comprises a wafer and a plurality of temperature sensors arranged in regions which are formed by segmenting the upper surface of the wafer into a plurality of regions. Each of the temperature sensors includes an oscillation circuit for oscillating a frequency signal corresponding to the temperature of its own region within a frequency band that is different for every region in response to input of power supply voltage.
1. A temperature measuring device comprising:
a wafer; and
a plurality of temperature sensors arranged in regions formed by segmenting the upper surface of said wafer into a plurality of regions, each of said temperature sensors comprising:
oscillation circuit for oscillating in response to receipt of a signal to output an oscillation frequency signal corresponding to a temperature of its own region, wherein
said signal is power supply voltage; and
wherein said oscillation circuit outputs an oscillation frequency signal corresponding to the temperature of its own region within a frequency band which is different for every region.
2. The temperature measuring device according to claim 1 , wherein
said oscillation circuit includes temperature dependent devices that change their characteristics depending on temperature, and thus changes its oscillation frequency with the characteristics changes of said temperature dependent devices.
3. The temperature measuring device according to claim 1 , wherein
said oscillation circuit outputs an oscillation frequency signal corresponding to the temperature of its own region within a frequency band which is the same for every region.
4. The temperature measuring device according to claim 1 , wherein said signal is a high-frequency signal and said oscillation circuit is a surface acoustic wave device for sending back a frequency signal corresponding to the temperature of its own region within a frequency bandwidth that is different for every region in response to input of the high frequency signal.
5. A temperature measuring device comprising:
a wafer-type temperature sensor including a wafer and a plurality of oscillation circuit, said oscillation circuit being arranged in regions formed by segmenting the upper surface of said wafer into a plurality of regions, and each of said oscillation circuit oscillating in response to receipt of power supply voltage to output an oscillation frequency signal corresponding to the temperature of its own region;
power supply unit for supplying power supply voltage to said oscillation circuit;
determination unit for determining the temperatures of the respective regions on said wafer based on the oscillation frequency signals oscillated by said plurality of oscillation circuit; and
communication unit for outputting the oscillation frequency signals oscillated by said oscillation circuit to said determination unit; and wherein
said plurality of oscillation circuit output oscillation frequency signals corresponding to the temperatures of their own regions within the respective frequency bands which are different for every region,
with reference to the oscillation frequency signals oscillated by the plurality of oscillation circuit, said determination unit determines each frequency band including the oscillation frequency signal to identify the region on the wafer corresponding to the frequency band, and determines the temperature of the region based on the oscillation frequency signal,
said communication unit outputs said oscillation frequency signals in the respective frequency bands by radio to the determination unit.
6. The temperature measuring device according to claim 5 , wherein
said power supply unit generates microwave signals serving as said power supply voltage,
said communication unit comprises:
a communication antenna located at a distance away from said wafer-type temperature sensor;
transmitter circuit for transmitting said microwave signals generated by said power supply unit through said communication antenna; and
receiver circuit for receiving the oscillation frequency signals within said frequency bands oscillated by said oscillation circuit through said communication antenna.
7. The temperature measuring device according to claim 6 , wherein
said wafer-type temperature sensor comprises:
transmitter circuit connected to the output of said oscillation circuit and for transmitting said oscillation frequency signals;
an element antenna connected to said transmitter circuit and for emitting said transmitted oscillation frequency signals by radio.
8. The temperature measuring device according to claim 5 , wherein
said plurality of oscillation circuit output oscillation frequency signals corresponding to the temperature of their own regions within a frequency band that is the same for every region,
said communication unit outputs the oscillation frequency signals within said frequency band to said determination unit by wire.