Mercury vapor high-pressure discharge lamp and irradiation method, particularly for mask pattern exposure of semiconductor wafers

US5650630A · kind A · utility

Assignee

• Patent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH · DE

Inventors

• Joern Dierks · Berlin, DE
• Juergen Maier · Weitersweiler, DE

Key dates

• Filing date: Mar 27, 1995
• Grant date: Jul 22, 1997
• Expiry date: Mar 27, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01J61/822
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

To eliminate radiation from the mercury high-pressure discharge lamp of wlengths below 365 nm, the lamp includes a discharge vessel of quartz glass which is doped with vanadium in a quantity of up to about only 250 ppm, by weight, with respect to 1 mm of wall thickness of the quartz glass. This absorbed radiation also heats the quartz glass, so that the outside wall temperature of the vessel can be maintained between about 400.degree. and 950.degree. C. The effect can be enhanced by adding, additionally, titanium and/or tin to provide metal ions to the doping substance, in an overall quantity of up to 500 ppm, by weight. Alternatively, the quartz glass can be coated with TiO.sub.2 or SnO.sub.2. Suitable wall thicknesses for the discharge vessel are between 1 and 5 mm, and the fill therein is preferably mercury in a quantity of between 0.5 and 15 mg/cm.sup.3 and xenon with a cold fill pressure of 0.1 to 2.5 bar. Electrode spacing of the lamp is preferably between 2 and 5 mm. The vanadium portion preferably is less than 200 ppm and may, most desirably, be between 20 and 150 ppm, with respect to 1 mm wall thickness of the quartz glass of the discharge vessel.