Abstract: A discharge lamp including a bulb hermetically filled with mercury and an anode and cathode facing each other within the light emitting space of the bulb. A thermal conductor plate is arranged at the end of the cathode where it contacts the electrode rod bearing the cathode. The anode is positioned above the cathode and almost all the mercury in the light emitting space of the bulb is condensed on the thermal conductor plate in the light emitting space when the discharge lamp is not lit. When the discharge lamp is lit, the heat generated at the cathode is transmitted to the thermal conductor plate through electrode rods. Simultaneously, the radiated heat is discharged from within the arc so that the mercury condensed on the thermal conductor plate is evaporated early resulting in the stabilization of the light emitting intensity of the radiated light within a short period of time.

Abstract: To provide a discharge lamp in which, by a simple procedure, the tip of the electrode support bar can be fitted easily into a concavity formed in the base of the electrode, and can be stably fixed to the electrode with high holding power, the discharge lamp has an electrode (13) supported by an electrode support bar (15) via the tip (15a) of the electrode support bar (15) engaging in a concavity (13a) formed in the base of the electrode, the tip of the electrode support bar (15) being provided with a slit (S) into which a spreader piece (20) is pressed to spread the slit (S). It is preferable that the electrode support bar (15) be made of molybdenum.

Abstract: A discharge lamp having an emission part with a roughly spherical external shape and tube arms extending from opposite sides of the emission part, hermetically sealing parts formed on an end of each robe arm, and a lead pin extending parallel to a longitudinal axis of the tube arm, a tip of each lead carrying an electrode in the emission part, so that a pair of electrodes are arranged opposite one another in the emission part. Within each babe arm, in the vicinity of the emission part, a plate-shaped holding part which is made of a metal with a high melting point and through which the lead pin penetrates, is arranged roughly perpendicularly to the lead pin and serves for positioning of the electrodes.

Abstract: A discharge lamp in which vaporization and melting of a cathode tip are prevented and which has stable luminous operation over a long is achieved according to the invention by the fact that the discharge lamp has a cathode in which a sintered body made of a powdered metal with a high melting point and a powdered emitter material is inserted in the tip, and the relationship:(-0.002d+0.01).ltoreq.D/W.ltoreq.(-0.002d+0.04)is fulfilled, where D is an outside diameter of the sintered body in millimeters (mm), W is a lamp input power in watts (w) and d is a distance between the anode and cathode in millimeters (mm). Furthermore, these benefits are achieved according to the invention by encapsulating mercury in an amount of 10 mg to 80 mg/cc of fluorescent tube internal volume and inert gas with at least 2 atm air pressure (at a reference temperature of 25.degree. C.).

Abstract: A semiconductor wafer one side of which has been coated with an ultraviolet sensitive material is exposed to light radiated from a rare gas-mercury discharge lamp. A rare gas-mercury discharge lamp filled with a rare gas such as xenon and mercury as principal luminous components thereof and capable of radiating light having the maximum peak wavelength at 365 nm is used as the lamp, and the coated side of the wafer is exposed, through a lens system having a high transmittance for light having a wavelength of 365 nm and a photomask, to the light radiated from the lamp so as to print a reduced image of the mask pattern on the coated side of the wafer. Use of the above-described rare gas-mercury discharge lamp allows to print a highly-integrated pattern having a narrow linewidth efficiently and in shorter exposure time owing to its high radiation intensity at 365 nm.

Abstract: Through a pattern mask, small sections of a semiconductor wafer are exposed successively to light radiated from a mercury-vapor lamp in high-level steps, during each of which the power consumption of the mercury-vapor lamp is at a high level, by continuously lighting the mercury-vapor lamp and repeatedly alternating each of the high-level steps and a low-level step during which the power consumption of the mercury-vapor lamp is at a low level. As the mercury-vapor lamp, there is used a mercury-vapor lamp in which mercury is filled in such a large amount that when lit in the low-level step, the mercury vapor pressure in its envelope is below 96% of the saturated mercury vapor pressure at that time. Use of such a mercury-vapor lamp is effective in avoiding the occurrence of incomplete lighting state when its power consumption is changed from the low-level step to the high-level step.

Abstract: Through a pattern mask, small sections of a semiconductor wafer are exposed successively to light radiated from a mercury-vapor lamp in high-level steps, during each of which the power consumption and discharge current of the mercury-vapor lamp are at a high level, by continuously lighting the mercury-vapor lamp and repeatedly alternating each of the high-level steps and a low-level step during which the power consumption and discharge current of the mercury-vapor lamp are at a low level. The alternation of the high-level step and low-level step is effected while controlling the magnitude of each of the overshoot and undershoot in the waveform of the discharge current for the mercury-vapor lamp below 10%. The exposure method of this invention is effective in avoiding or minimizing the wearing of electrodes of a mercury-vapor lamp. Thus, the mercury-vapor lamp can enjoy long service life while permitting stable exposure over a long period of time.

Abstract: A discharge lamp of the type which seals mercury and a rare gas in a bulb having sealed therein a pair of electrodes and in which both the mercury and the rare gas contribute to discharge radiation. Letting the value of the quantity of mercury (mg/cc.) sealed per 1 cc. of the volume of the bulb and the value of the (atmospheric) pressure of the rare gas be represented by X and Y, respectively, the values X and Y are selected to be in the ranges of 1.ltoreq.X.ltoreq.13 and 2.ltoreq.Y.ltoreq.10, respectively, whereby to abundantly emit ultraviolet rays of the wavelengths between 2000 to 2500 A. The discharge lamp is employed as a light source for photolithography in the manufacture of semiconductor devices to achieve the formation of a fine pattern in a short time.