JPH0732003B2 - 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 that causes a photochemical reaction, and particularly for improving the heat resistance of a resist when manufacturing a semiconductor. The present invention relates to a metal vapor discharge lamp preferably used for hardening and the like.

[Background of the Invention]

Generally, in the manufacture of semiconductors, after irradiating a resist film applied on a wafer substrate with ultraviolet rays through a predetermined image pattern, the resist film is dissolved with a resist solution or the like to form a resist pattern of a fine image, In order to improve the adhesiveness of the resist, post-baking is performed, but because the heat resistance of the resist is inferior during this post-baking, the resist pattern of the fine image may peel off from the wafer or cause mold deviation. Before or after the 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, it is said to be unfavorable because it causes a bubbling phenomenon depending on the type of resist.

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 emission of light from this 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 emits light outside the wavelength range effective for the above photochemical reaction. So, 330nm
The above long-wavelength spectrum line is blocked by a filter and used for resist hardening, but there is a problem that the effective wavelength region is also attenuated.

Therefore, recently, a metal vapor discharge lamp, for example, a magnesium vapor discharge lamp in which magnesium is enclosed, has been developed in which a metal halide is enclosed as a light emitting substance in the arc tube in addition to mercury as a light emitting substance to increase the emission amount of light of a specific wavelength. There is a problem in that the effect of increasing the spectrum output in the effective wavelength range is small even if magnesium is enclosed.

Under such circumstances, a metal vapor discharge lamp that emits ultraviolet rays that sufficiently causes a desired photochemical reaction with high efficiency has not yet been obtained.

[Object of the Invention]

The object of the present invention is based on the above circumstances, the object is to provide a metal vapor discharge lamp that highly efficiently radiates ultraviolet rays in a wavelength range effective for photochemical reactions, particularly ultraviolet rays of 330 nm or less. To provide.

[Means for solving problems]

The metal vapor discharge lamp of the present invention is a metal vapor discharge lamp in which mercury, magnesium, halogen and a rare gas are enclosed in an arc tube, and at least one of tin and bismuth is enclosed as an auxiliary component for causing the magnesium to emit light. It is characterized by becoming.

[Advantageous effects of the invention]

The metal vapor discharge lamp of the present invention contains mercury, magnesium, halogen and a rare gas inside the arc tube, and since at least one or more of tin and bismuth is enclosed as a light emission assisting component of magnesium, an effective wavelength of 220 to 330 nm. The ultraviolet rays in the range can be efficiently emitted.

As described above, the wavelength range effective for hardening the semiconductor resist is ultraviolet rays in the range of 220 to 330 nm, and it is required to increase the amount of light emission in this range. In addition, magnesium, halogen, and rare gas are sealed, and tin, bismuth alone or a halide is added and sealed as an auxiliary component, so it is difficult for the magnesium to emit light by itself, and it strongly emits light due to the interaction with tin and bismuth. It shows a strong energy distribution in the effective wavelength range for resist hardening.

Although its principle cannot be elucidated at present, tin and bismuth are effective in increasing the output of magnesium at 278, 280, 285 and 309 nm, as will be apparent from the examples described later.

The addition amounts of tin and bismuth may be very small, and for example, the addition of 2 to 5 × 10 ^-8 mol per 1 cc of the inner volume of the arc tube can provide a sufficiently large effect. The same effect can be obtained by using a halide of tin or bismuth instead of the simple substance.

[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.
Shows a 4KW magnesium evaporative discharge lamp with an inner diameter of 22mm,
Arc tube 1 consisting of an ozone-less quartz tube with an internal volume of about 100cc
A pair of electrodes 2 and 2 are located inside each other, and the electrode tube distance is 25
It is 0 mm. Both ends of the arc tube 1 are seal portions 11, and molybdenum foil 3 is enclosed in the seal portions 11, and the outer conducting wire 3 and the electrode 2 are electrically connected via the molybdenum foil 3.

The arc tube 1 is filled with 170 mg of mercury, 1 × 10 ⁻⁵ mol of magnesium iodide and 15 Toor of argon gas. Then, 3 × 10 ^-6 mol of tin iodide was added and encapsulated (Lamp A), and 5 × 10 ^-6 mol of bismuth iodide was encapsulated (Lamp B) and tin iodide was 1 × 10 ^-6. Molar and bismuth iodide at 1 × 10 ⁻⁶ mol (Lamp C), and as comparative examples, tin iodide and bismuth iodide were not added at all (Lamp D). It was measured. 2 is a lamp A, FIG. 3 is a lamp B, FIG. 4 is a lamp C, and FIG.

As can be seen from these figures, a lamp A, a lamp B and a lamp C each containing at least one of tin and bismuth as an auxiliary component for causing the magnesium to emit light in a sealed gas of mercury, magnesium, halogen and a rare gas.
In FIGS. 2, 3, and 4], the emission spectrum of magnesium in the effective wavelength range is greatly increased as compared with the lamp D (FIG. 5) to which tin and bismuth are not added, and the effect You can confirm the big thing.

Therefore, by adding a small amount of at least one of tin and bismuth, or both of them, the output of the emission spectrum of magnesium can be greatly increased. Therefore, for photochemical reaction, especially for resist hardening (stabilization) and curing of printing ink. The discharge lamp for ultraviolet rays is suitable for other uses.

Also, if it is used as a light source for resist hardening by blocking a spectrum of 350 nm or more with a filter or the like, 220
It is effective because it has a strong output at ~ 330 nm.

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 mercury, magnesium, halogen and a rare gas are enclosed in the arc tube, and at least tin and bismuth are used as auxiliary components for causing the magnesium to emit light. Since it is configured to enclose one or more types, it is effective in the photochemical reaction, especially in the resist hardening.
The output of the emission spectrum of nm magnesium can be greatly increased.

[Brief description of drawings]

1 is an explanatory sectional view showing an embodiment of a metal vapor discharge lamp according to the present invention, and FIGS. 2 to 4 are graphs showing an output distribution of an emission spectrum in the metal vapor discharge lamp of the present invention.
FIG. 5 is a graph showing the output distribution of the emission spectrum of the conventional metal vapor discharge lamp. 1 ... Arc tube, 2 ... Electrode 3 ... Molybdenum foil, 4 ... Outer conductor wire 11 ... Seal part

Claims (1)

[Claims] 1. A metal vapor discharge lamp in which mercury, magnesium, halogen and a rare gas are enclosed in an arc tube, wherein at least one of tin and bismuth is enclosed as an auxiliary component for causing the magnesium to emit light. And a metal vapor discharge lamp.