US5748656A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser having improved beam quality and reduced operating cost
Assignee: Cymer LLC
•
Filing: 1996-01-05
•
Granted: 1998-05-05
•
Expires: 2016-01-05
Abstract
Abstract Disclosed is a laser useful in, e.g., photolithography or medical surgery. In one embodiment, the laser comprises a discharge chamber and heat-generating electronics that are enclosed in a baffled enclosure that requires less cooling air to reliably cool the components in the enclosure than previous unbaffled enclosures. A method of reducing the amount of conditioned air is also provided. In a further embodiment, the laser has a heat-exchange system that acts quickly in response to changes in laser gas temperature by adjusting a flow-proportioning valve regulating water flow through a heat exchanger, thereby providing a continuously variable rate of heat exchange through the heat exchanger to maintain the lasing gas temperature constant. Methods of providing a laser beam and of improving the uniformity of a laser beam are disclosed, as are photolithography methods utilizing a laser and method of this invention.
Inventors
- 👤 Tom A. Watson
- 👤 William N. Partlo
- 👤 Donald G. Larson
- 👤 Igor V. Fomenkov
- 👤 Anthony J. de Ruyter
- 👤 Palash P. Das
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:22
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/02; H01S3/03; H01S3/036; H01S3/04; H01S3/041; F; F28; F28D; F28D21/00; F28D2021/0019; F28D2021/0077; H01S3/14; H01S3/22; H01S3/223; H01S3/225
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
117 words
A laser comprising a) a discharge chamber for generating a laser beam; b) a lasing gas within said discharge chamber; c) a temperature sensor positioned to read the temperature of said lasing gas and thermally optimized by utilizing materials having a small thermal time constant, to generate a real-time temperature signal indicative of the lasing gas temperature; and d) a heat exchange system positioned to add heat to or remove heat from the lasing gas, wherein the heat exchange system comprises a heat exchanger whose rate of heat exchange is continuously variable in response to the temperature signal, and the rate of heat exchange is adjusted in response to a real-time temperature signal from the temperature sensor.
Claim 2
Dependent Claim
117 words
A laser comprising a) a discharge chamber for generating a laser beam; b) a lasing gas within said discharge chamber; c) a temperature sensor positioned to read the temperature of said lasing gas and thermally optimized by utilizing materials having a small thermal time constant, to generate a real-time temperature signal indicative of the lasing gas temperature; and d) a heat exchange system positioned to add heat to or remove heat from the lasing gas, wherein the heat exchange system comprises a heat exchanger whose rate of heat exchange is continuously variable in response to the temperature signal, and the rate of heat exchange is adjusted in response to a real-time temperature signal from the temperature sensor.
Claim 3
Dependent Claim
17 words
The laser of claim 1 wherein the lasing gas comprises a noble gas halide under lasing conditions.
Claim 4
Dependent Claim
24 words
The laser of claim 1 wherein the heat exchange medium of the heat exchanger comprises a liquid which removes heat from the lasing gas.
Claim 5
Dependent Claim
75 words
The laser of claim 3 wherein the laser further comprises a housing and the heat exchange system comprises components through which the heat exchange medium flows, at least one of which components is positioned within the discharge chamber and at least one of which components is positioned outside the discharge chamber but within the housing, and wherein the components that are positioned outside the discharge chamber but within the housing are positioned within a sub-assembly.
Claim 6
Dependent Claim
33 words
The laser of claim 3 wherein the heat exchange system further comprises a flow-proportioning valve through which said liquid flows and wherein the flow of said liquid is controlled by the flow-proportioning valve.
Claim 7
Dependent Claim
13 words
The laser of claim 5 wherein the flow-proportioning valve is a 3-way valve.
Claim 8
Dependent Claim
22 words
The laser of claim 5 wherein the temperature sensor is a temperature sensor located in the lasing gas within the discharge chamber.
Claim 9
Dependent Claim
17 words
The laser of claim 5 wherein the lasing gas comprises a noble gas halide under lasing conditions.
Claim 10
Dependent Claim
17 words
The laser of claim 7 wherein the lasing gas comprises a noble gas halide under lasing conditions.
Claim 11
Dependent Claim
17 words
The laser of claim 1 wherein the temperature sensor is a thermocouple located in the lasing gas.
Claim 12
Dependent Claim
19 words
The laser of claim 1 wherein the temperature sensor is a semiconductor temperature sensor located in the lasing gas.
Claim 13
Dependent Claim
45 words
The laser of claim 1 wherein the temperature sensor is located in the portion of the lasing gas that is representative of the temperature of the bulk of the lasing gas that is being subjected to the energy that pumps electrons to an excited state.
Claim 14
Dependent Claim
12 words
The laser of claim 12 wherein the temperature sensor is a thermocouple.
Claim 15
Dependent Claim
14 words
The laser of claim 12 wherein the temperature sensor is a semiconductor temperature sensor.
Claim 16
Dependent Claim
18 words
The laser of claim 14 wherein the thermocouple is positioned in the lasing gas within the discharge chamber.
Claim 17
Dependent Claim
20 words
The laser of claim 14 wherein the semiconductor temperature sensor is positioned in the lasing gas within the discharge chamber.
Claim 18
Dependent Claim
27 words
The laser of claim 16 wherein a rod-type heating element is disposed in said discharge chamber to maintain the lasing gas temperature during inoperation of said laser.
Claim 19
Independent Claim
118 words
A method for improving the uniformity of a laser beam of a laser having a discharge chamber, a volume of lasing gas within said discharge chamber, a temperature sensor positioned to read the temperature of said lasing gas and which generates a temperature signal indicative of the lasing gas temperature, and a heat exchanger positioned to add heat to or remove heat from the lasing gas, said method comprising comparing the lasing gas temperature as indicated by the temperature signal to a set-point and adjusting the instantaneous rate of addition or removal of heat through the heat exchanger to maintain the temperature of the lasing gas in the discharge chamber, as read by the temperature sensor, essentially constant.
Claim 20
Independent Claim
118 words
A method for improving the uniformity of a laser beam of a laser having a discharge chamber, a volume of lasing gas within said discharge chamber, a temperature sensor positioned to read the temperature of said lasing gas and which generates a temperature signal indicative of the lasing gas temperature, and a heat exchanger positioned to add heat to or remove heat from the lasing gas, said method comprising comparing the lasing gas temperature as indicated by the temperature signal to a set-point and adjusting the instantaneous rate of addition or removal of heat through the heat exchanger to maintain the temperature of the lasing gas in the discharge chamber, as read by the temperature sensor, essentially constant.
Claim 21
Dependent Claim
29 words
The method of claim 18, wherein the method further comprises maintaining the amount of said lasing gas essentially constant by adding a consumable gas during operation of the laser.
Claim 22
Dependent Claim
20 words
The method of claim 18 wherein the lasing gas of said method comprises a noble gas halide under lasing conditions.
Claim 23
Dependent Claim
60 words
The method of claim 18 wherein the function of adjusting the instantaneous rate of removal of heat through the heat exchanger to maintain the temperature of the lasing gas in the discharge chamber, as read by the temperature sensor, essentially constant comprises passing a heat-exchange liquid through said heat exchanger under conditions sufficient to remove heat from said lasing gas.
Claim 24
Dependent Claim
74 words
The method of claim 21 wherein the heat-exchange liquid used to remove heat from the lasing gas flows through components, at least one of which components is positioned within the discharge chamber and at least one of which components is positioned outside the discharge chamber but within a housing which encloses the discharge chamber, and wherein the components that are positioned outside the discharge chamber but within the housing are positioned within a sub-assembly.
Claim 25
Dependent Claim
77 words
The method of claim 21 wherein the function of adjusting the instantaneous rate of removal of heat through the heat exchanger to maintain the temperature of the lasing gas in the discharge chamber, as read by the temperature sensor, essentially constant is performed by controlling the flow of said heat-exchange liquid through said heat exchanger by passing the heat-exchange liquid through a flow-proportioning valve and regulating the flow rate of said heat-exchange fluid using said flow-proportioning valve.
Claim 26
Dependent Claim
19 words
The method of claim 23 wherein the flow-proportioning valve through which said heat-exchange fluid passes is a 3-way valve.
Claim 27
Dependent Claim
22 words
The method of claim 23 wherein the temperature sensor is a temperature sensor located in the lasing gas within the discharge chamber.
Claim 28
Dependent Claim
27 words
The method of claim 23 wherein the method further comprises selecting the lasing gas such that the lasing gas produces a noble metal halide under lasing conditions.
Claim 29
Dependent Claim
12 words
The method of claim 25 wherein the laser is an excimer laser.
Claim 30
Dependent Claim
18 words
The method of claim 18 wherein the temperature sensor is a temperature sensor located in the lasing gas.
Claim 31
Dependent Claim
45 words
The method of claim 18 wherein the temperature sensor is located in the portion of the lasing gas that is representative of the temperature of the bulk of the lasing gas that is being subjected to the energy that pumps electrons to an excited state.
Claim 32
Dependent Claim
12 words
The method of claim 29 wherein the temperature sensor is a thermocouple.
Claim 33
Dependent Claim
18 words
The method of claim 30 wherein the thermocouple is positioned in the lasing gas within the discharge chamber.
Claim 34
Dependent Claim
14 words
The method of claim 29 wherein the temperature sensor is a semiconductor temperature sensor.
Claim 35
Dependent Claim
20 words
The method of claim 32 wherein the semiconductor temperature sensor is positioned in the lasing gas within the discharge chamber.
Claim 36
Independent Claim
116 words
A method for generating a laser beam having improved uniformity from a laser having a discharge chamber, a volume of lasing gas, a temperature sensor that generates a temperature signal indicative of the lasing gas temperature, and a heat exchanger for adding heat to or removing heat from the lasing gas, said method comprising a) stimulating photon emission from the lasing gas in the discharge chamber of the laser, b) comparing the lasing gas temperature as indicated by the temperature signal to a set-point, and c) adjusting the instantaneous rate of addition or removal of heat through the heat exchanger to maintain the temperature of the lasing gas, as read by the temperature sensor, essentially constant.
Claim 37
Independent Claim
116 words
A method for generating a laser beam having improved uniformity from a laser having a discharge chamber, a volume of lasing gas, a temperature sensor that generates a temperature signal indicative of the lasing gas temperature, and a heat exchanger for adding heat to or removing heat from the lasing gas, said method comprising a) stimulating photon emission from the lasing gas in the discharge chamber of the laser, b) comparing the lasing gas temperature as indicated by the temperature signal to a set-point, and c) adjusting the instantaneous rate of addition or removal of heat through the heat exchanger to maintain the temperature of the lasing gas, as read by the temperature sensor, essentially constant.
Claim 38
Dependent Claim
137 words
A photolithography method comprising a) placing a photoresist on a substrate, and b) patterning the photoresist with a laser beam, wherein the laser beam is generated by a laser having a discharge chamber, a volume of lasing gas, a temperature sensor that generates a temperature signal indicative of the lasing gas temperature, and a heat exchanger for adding heat to or removing heat from the lasing gas, and wherein the laser beam is generated by the method comprising stimulating photo emission from the lasing gas in the discharge chamber of the laser; comparing the lasing gas temperature as indicated by the temperature signal to a set-point; and adjusting the instantaneous rate of addition or removal of heat through the heat exchanger to maintain the temperature of the lasing gas, as read by the temperature sensor, essentially constant.
Claim 39
Dependent Claim
137 words
A photolithography method comprising a) placing a photoresist on a substrate, and b) patterning the photoresist with a laser beam, wherein the laser beam is generated by a laser having a discharge chamber, a volume of lasing gas, a temperature sensor that generates a temperature signal indicative of the lasing gas temperature, and a heat exchanger for adding heat to or removing heat from the lasing gas, and wherein the laser beam is generated by the method comprising stimulating photo emission from the lasing gas in the discharge chamber of the laser; comparing the lasing gas temperature as indicated by the temperature signal to a set-point; and adjusting the instantaneous rate of addition or removal of heat through the heat exchanger to maintain the temperature of the lasing gas, as read by the temperature sensor, essentially constant.
Claim 40
Dependent Claim
136 words
A photolithography method comprising a) placing a photoresist on a substrate, and b) patterning the photoresist with a laser beam generated by a laser which comprises a discharge chamber for generating a laser beam; a lasing gas within said discharge chamber; a temperature sensor positioned to read the temperature of said lasing gas and thermally optimized by utilizing materials having a small thermal time constant, to generate a real-time temperature signal indicative of the lasing gas temperature; and a heat exchange system positioned to add heat to or remove heat from the lasing gas, wherein the heat exchange system comprises a heat exchanger whose rate of heat exchange is continuously variable in response to the temperature signal, and the rate of heat exchange is adjusted in response to a real-time temperature signal from the temperature sensor.
Claim 41
Dependent Claim
136 words
A photolithography method comprising a) placing a photoresist on a substrate, and b) patterning the photoresist with a laser beam generated by a laser which comprises a discharge chamber for generating a laser beam; a lasing gas within said discharge chamber; a temperature sensor positioned to read the temperature of said lasing gas and thermally optimized by utilizing materials having a small thermal time constant, to generate a real-time temperature signal indicative of the lasing gas temperature; and a heat exchange system positioned to add heat to or remove heat from the lasing gas, wherein the heat exchange system comprises a heat exchanger whose rate of heat exchange is continuously variable in response to the temperature signal, and the rate of heat exchange is adjusted in response to a real-time temperature signal from the temperature sensor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-05-04 | 2001-11-03 | 2002-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-04 | 2005-11-03 | 2006-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-04 | 2009-11-03 | 2010-05-05 | $7700.00 | Window Closed / Lapsed |