Arrangement for feeding or dissipating heat to/from a semiconductor substrate for the purpose of preparing or post-processing a lithographic projection step
View Patent ↗The arrangement comprises a hot or cool plate ( 12 ) that has a substantially planar surface for accommodating the semiconductor substrate and for transmitting heat between the hot or cool plate and the semiconductor substrate, a source ( 10 ) of heat or cold that is connected to the hot or cool plate ( 12 ) for the purpose of heating or cooling, a device ( 25 ) for depositing or lifting the semiconductor substrate ( 8 ) onto/from the surface of the hot or cool plate ( 12 ). A light source ( 200 ) can be used to generate a focused light beam ( 80 ), preferably a laser beam, which is detected by a detector ( 100 ) with at least one sensor ( 110–140 ) after reflection by a wafer ( 8 ) deposited on the hot or cool plate ( 12 ). A control unit that is connected to the detector ( 100 ) for the purpose of evaluating a position of the reflected light beam determines a possible deposition error by comparing the position with one of a wafer ( 8 ) deposited with its entire surface on the hot or cool plate ( 12 ). A device ( 25 ) for depositing or lifting the semiconductor substrate is controlled in this case, the wafer being lifted and redeposited again.
1. An arrangement for feeding or dissipating heat to/from a semiconductor substrate for the purpose of preparing or post-processing a lithographic process, comprising:
at least one plate that has a substantially planar surface for accommodating the semiconductor substrate and for transmitting heat between the plate and the semiconductor substrate;
a source of heat or cold that is coupled to the plate for the purpose of heating or cooling the plate;
a light source for generating a focused light beam and directing the light beam toward an upper surface of the semiconductor substrate, wherein the upper surface of the substrate is coated with photosensitive resist and wherein the light source for generating the focused light beam is a laser diode that emits a light beam with a wavelength of more than 600 nanometers;
a detector with at least one sensor for detecting the light beam generated by the light source and reflected by the semiconductor substrate; and
a control unit coupled to the detector for the purpose of evaluating a position of the reflected light beam.
2. The arrangement as claimed in claim 1 , wherein the detector comprises a four-fold photodiode with four photodiodes arranged around a midpoint.
3. The arrangement as claimed in claim 2 , wherein each of the four photodiodes is connected as a resistor in a bridge circuit.
4. The arrangement as claimed in claim 1 , wherein the detector comprises a CCD chip.
5. The arrangement as claimed in claim 1 and further comprising a device for moving the semiconductor substrate relative to the surface of the plate.
6. The arrangement as claimed in claim 5 wherein the control unit is coupled to the device for moving the semiconductor substrate.
7. The arrangement as claimed in claim 1 wherein the plate comprises a hot plate.
8. The arrangement as claimed in claim 1 wherein the plate comprises a cool plate.
9. The arrangement as claimed in claim 1 wherein the light source comprises a laser light source.
10. A method of processing a semiconductor wafer, the method comprising:
placing a semiconductor wafer on a thermal plate;
irradiating a focused light beam onto an upper surface of the semiconductor wafer, wherein the upper surface of the wafer is coated with photosensitive resist and wherein the focused light beam has a wavelength of more than 600 nanometers;
reflecting the light beam from the upper surface of the semiconductor wafer in the direction of a detector;
detecting the light beam in order to establish an oblique position of the semiconductor wafer on the thermal plate;
raising and once again placing the semiconductor wafer on the thermal plate as a function of a result of detection; and
comprising heating or cooling the thermal plate in order to feed or dissipate heat to/from the semiconductor substrate.
11. The method of claim 10 wherein placing a semiconductor wafer on a plate comprises placing a semiconductor wafer on a hot plate.
12. The method of claim 10 wherein placing a semiconductor wafer on a plate comprises placing a semiconductor wafer on a cool plate.
13. The method of claim 10 and further comprising, after raising and once again placing, repeating the steps of irradiating, reflecting and detecting.
14. The method of claim 10 wherein the detecting step comprises detecting a semiconductor wafer deposited at least partially on a projecting position mark of the plate.