Exposure method of semiconductor wafer by rare gas-mercury discharge lamp

In a method for producing with high resolution a pattern image on a semiconductor wafer, one side of which has been coated with an ultraviolet sensitive material, by exposing the wafer to light emitted from a discharge lamp, the improvement comprising;

• filling the discharge lamp with fill consisting essentially of 0.1-5 atmospheres of zenon at room temperature and with 1-30 milligrams of mercury per cubic centimeter, at room temperature, of the interior space of the envelope of said discharge lamp;
• radiating from the lamp light having a peak wavelength of 365 nm;
• projecting said light through a lens system having a high transmittance for light having a wavelength of 365 nm, through a photomask defining a pattern and through a filter having a transmittance of at least 90% for light having a wavelength of 365 nm;
• and
• exposing the coated side of the semiconductor wafer to the projected light so as to print a reduced image of the photomask pattern on the coated side of the wafer wherein the minimum line width of the image is 0.8 .mu.m.