JPH0732000B2 - Metal vapor discharge lamp - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a metal vapor discharge lamp used as an ultraviolet light source for causing a photochemical reaction, and particularly for improving heat resistance of a resist when manufacturing a semiconductor. The present invention relates to a metal vapor discharge lamp preferably used for hardening performed.

BACKGROUND OF THE INVENTION In general, in the manufacture of semiconductors, a resist film coated on a wafer substrate is irradiated with ultraviolet rays through a predetermined image pattern and then dissolved in a resist solution or the like to form a fine image resist pattern. Then, post-baking is performed to improve the adhesiveness of the resist, but because the heat resistance of the resist is poor during this post-baking, the resist pattern of the fine image may peel off from the wafer or be misaligned. Before or after post-baking, the resist remaining on the wafer substrate is further irradiated with ultraviolet rays to be cured (hereinafter referred to as "hardening").
Then, the exposed wafer is subjected to a process such as impurity ion implantation. The hardening of this resist is due to the photochemical reaction of the polymer compound by light absorption, and the most effective wavelength range of light is the ultraviolet range of about 220 to 330 nm and the output of 330 to 450 nm. If it is strong, a foaming phenomenon may occur depending on the type of resist, which is not preferable.

Conventionally, a low-pressure mercury lamp or a high-pressure mercury lamp has been generally used as a light source lamp for irradiating this ultraviolet ray, but the former high-pressure mercury lamp is mainly used because the arc length becomes long and a large output cannot be obtained. ing.

[Problems to be solved by the invention]

However, the light emitted from the high-pressure mercury lamp is composed of a large number of emission line spectra, and each spectrum is dispersed over a considerably wide wavelength range, so that it strongly radiates other than the wavelength range effective for the above-mentioned hardening. Especially, since the long-wavelength spectrum line of 330 nm or more is harmful, it is blocked by a filter and used for resist hardening.
The filter has a problem that it also attenuates the effective wavelength range.

Therefore, recently, a metal vapor discharge lamp that emits light of a specific wavelength by encapsulating another metal halide as a light emitting substance without adding mercury in the arc tube has been developed. The output is lower than that of mercury.

Under such circumstances, a metal vapor discharge lamp that sufficiently causes a desired photochemical reaction without using mercury, particularly a semiconductor manufacturing resist that is cured, emits ultraviolet rays in a range of 220 to 330 nm with high efficiency is a metal vapor discharge lamp. However, the fact is that it has not been obtained yet.

[Object of the Invention]

The object of the present invention is based on the above-mentioned circumstances, and the object thereof is to achieve high efficiency of ultraviolet rays in a wavelength range effective in photochemical reaction, particularly in hardening for improving the heat resistance of a semiconductor resist. It is to provide a metal vapor discharge lamp that does not add radiating mercury.

[Means for solving problems]

The metal vapor discharge lamp of the present invention is a metal vapor discharge lamp in which a halogen, a buffer gas, and at least one or more of tin and bismuth as a luminescent material are enclosed in a mercury-free arc tube.
It is characterized by enclosing 300 Toor of xenon gas.

[Advantageous effects of the invention]

The metal vapor discharge lamp of the present invention is 330 nm without using mercury.
Since at least one of tin and bismuth having the main emission line spectrum is encapsulated below, it is possible to efficiently emit ultraviolet rays in the effective wavelength range of 220 to 330 nm. Moreover, since xenon gas is used as the filling gas, the output in the effective wavelength range of 220 to 330 nm can be significantly increased as compared with the argon gas. The xenon gas tends to increase the spectral intensities of tin and bismuth in proportion to the enclosed amount (partial pressure of the xenon gas), but the enclosed amount of the xenon gas is preferably in the range of 5 to 300 Toor at room temperature. If it is less than 5Toor, the effect of increasing the output in the effective wavelength range is small, and if it exceeds 300Toor, the arc between the electrodes of the arc tube becomes thin and begins to rise, and further the arc contacts the arc tube and devitrification occurs. Is not preferred.

That is, as described above, the wavelength range effective for hardening the semiconductor resist is ultraviolet rays in the range of 220 to 330 nm, and in order to increase the emission amount in this range, tin or bismuth is used instead of mercury. At least one of the above is pressure-sealed in the photoelectric tube, and 5-300 Too as a buffer gas.
The metal vapor discharge lamp of the present invention in which xenon gas is sealed in r can be used as a light source that emits an ultraviolet ray output effective for resist hardening.

When tin or bismuth is sealed in the arc tube,
A simple metal and a halogen or a halide thereof are used. Tin and bismuth may be enclosed in a very small amount, and for example, a sufficiently large effect can be obtained by adding 3 to 5 × 10 ^-8 mol per 1 cc of internal volume of the arc tube.

When manganese and lead are enclosed, the output of 220 to 330 nm can be increased, but the output of 330 to 450 nm that causes the phenomenon of bubbling of the resist is also increased, which is not preferable for hardening the resist.

[Specific configuration of the invention]

 Hereinafter, the present invention will be specifically described.

〔Example〕

Figure 1 shows the rating used as a light source in photochemical reactions.
A metal vapor discharge lamp of 4 KW is shown, in which a pair of electrodes 2 and 2 are opposed to each other in an arc tube 1 made of an ozoneless quartz tube having an inner diameter of 22 mm and an internal volume of about 100 cc, and the distance between the electrodes is 250 mm. Both ends of the arc tube 1 are seal portions 11, and molybdenum foil 3 is sealed on the seal portions 11, and the external lead rods 4 and the electrodes 2 are electrically connected via the molybdenum foil 3.

2.6 m of tin iodide is placed in the arc tube 1 constructed as described above.
g, a mixture of 0.25 mg tin and 0.7 mg bismuth iodide, 150 T
A metal vapor discharge lamp was produced by enclosing oor xenon gas. Further, for comparison, another one was prepared in which argon, a buffer gas, and argon gas were enclosed at a pressure of 150 Toor, with the same amounts of tin, bismuth, and halides, for comparison.

FIG. 2 and FIG. 3 are graphs showing the spectral distribution of the emission spectrum of the metal vapor discharge lamp of the present invention and the spectral distribution of the emission spectrum of the metal vapor discharge lamp of the comparative example, with the horizontal line representing the emission line spectrum. The wavelength (nm) is shown and the output relative value (%) is shown on the vertical axis. The absolute energy value at 100% is the same in both figures.

As is clear from these figures, the effective wavelength range 220 to 3 of the xenon gas-containing metal vapor discharge lamp of the present invention shown in FIG.
The output relative value of 30 nm is 10 relative to the output relative value of the effective wavelength range 220 to 330 nm of the metal vapor discharge lamp containing argon gas shown in FIG.
If it is 0, it is 189, which is up to about 1.9 times, but the increase rate in the region of 330 to 450 nm, which is harmful to resist hardening, is 1.35 times in relative output value, and the effective wavelength range increases. Is remarkable.

Furthermore, the output relative value in the harmful spectrum region can be drastically reduced as compared with the conventional mercury lamp, and a metal vapor discharge lamp suitable for resist hardening can be provided.

Further, the addition of tin or bismuth has almost no effect on the electrical characteristics such as the starting voltage and the re-ignition voltage.

As described above, the metal vapor discharge lamp of the present invention is a metal vapor discharge lamp in which at least one or more of tin and bismuth as a luminescent substance is enclosed in an arc tube containing no mercury, Since the xenon gas of 5 to 300 Toor is filled as the buffer gas, the emission spectrum output in the wavelength range 220 to 330 nm, which is effective for the photochemical reaction, particularly the hardening of the resist, can be greatly increased.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view showing an embodiment of a metal vapor discharge lamp according to the present invention, FIG. 2 is a graph showing a spectral distribution of an emission spectrum in the metal vapor discharge lamp of the present invention, and FIG. 3 is a comparison. It is a graph which shows the spectral distribution of the example metal vapor discharge lamp. 1 ... Arc tube, 2 ... Electrode 3 ... Molybdenum foil, 4 ... Outer conductor 11 ... Seal part

Claims (1)

[Claims] 1. A metal vapor discharge lamp in which a halogen, a buffer gas, and at least one of tin and bismuth as a luminescent material are enclosed in a mercury-free arc tube, wherein the buffer gas is 5 to 300 Toor xenon gas. A metal vapor discharge lamp, characterized in that