JPH0732001B2 - 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 the heat resistance of a resist when manufacturing a semiconductor. The present invention relates to a metal vapor discharge lamp used for hardening.

[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.

The emission of light from this high-pressure mercury lamp consists of a number of emission line spectra, and each spectrum is dispersed over a fairly wide wavelength range. Spectral lines are blocked by a filter and used for resist hardening.

Furthermore, recently, a metal vapor discharge lamp has been developed in which a metal halide is enclosed as a luminescent substance in the arc tube without adding mercury to obtain light emission of a specific wavelength.

[Problems to be solved by the invention]

However, for example, in a metal vapor discharge lamp in which magnesium, halogen, and a rare gas are enclosed without enclosing mercury in the arc tube, the output of the spectrum in the effective wavelength range due to the encapsulation of magnesium is low, and the conventional mercury lamp is rather used. Compared with this, there is a problem that the output of the spectrum in the effective wavelength region is small.

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 has been made based on the above circumstances, and the object is to highly efficiently treat 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 magnesium and halogen are enclosed in a mercury-free arc tube, which is characterized in that tin and xenon gas of 5 to 300 Toor are enclosed.

[Advantageous effects of the invention]

Since the metal vapor discharge lamp of the present invention does not use mercury, it has a small output of 350 nm or more and can efficiently emit ultraviolet rays in the effective wavelength range of 220 to 330 nm.

Mercury is generally used as a light-emitting substance enclosed in a mercury lamp, but it is rather harmful to resist hardening due to its high spectral output of 350 nm or more. Magnesium is used as a light emitting material instead of mercury, and tin is enclosed in an arc tube together with halogen and xenon as an auxiliary component.

Although this magnesium has a small spectral output when used alone, it emits light with high efficiency in the coexistence state of tin and xenon gas, and is particularly effective in the hardening of semiconductor manufacturing resists. The amount of light emission increases.

In the present invention, xenon is used instead of argon as the rare gas for starting the arc discharge, and the effective wavelength range 220
It increases the UV radiation energy output of ˜330 nm, and the enclosed amount is preferably in the range of 5 to 300 Toor at room temperature. Effective wavelength range 2 when xenon gas is less than 5Toor
There is little effect of increasing the output of 20 to 330 nm, and when it exceeds 300Toor, the arc becomes thin and a lifting phenomenon occurs,
Further, the arc comes into contact with the photoelectric tube, causing devitrification of the arc, which is not preferable.

As the auxiliary component tin, it is preferable to encapsulate in the form of a simple metal or a halide thereof. At present, it is not possible to elucidate the principle, but tin, as can be seen from the examples described later, is
Useful for increasing the output at 285 and 309 nm. The amount of tin added may be extremely small, for example, the internal volume of the arc tube.
A sufficiently large effect can be obtained with an addition amount of 2 to 5 × 10 ^-8 mol per cc.

[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 4KW is shown, in which a pair of electrodes 2 and 2 are positioned opposite 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 an electrode tube distance is 250 mm. Both ends of the arc tube 1 are seal portions 11, and molybdenum foil 3 is sealed in the seal portion 11, and the molybdenum foil is electrically connected to the external lead rod 4 and the electrode 2.

1 × 10 ⁻⁵ mol of magnesium iodide, 5 × 10 ⁻⁶ mol of antimony iodide in the arc tube 1 having the above-mentioned structure,
A metal vapor discharge lamp (lamp A) filled with 5 × 10 ⁻⁶ mol of tin iodide and 150 Toor of xenon gas was produced.

FIG. 2 is a graph showing the spectral distribution of the emission spectrum of the metal vapor discharge lamp (lamp A) of the present invention, where the horizontal axis shows the wavelength (nm) of the bright line spectrum and the vertical axis shows the relative spectral intensity ( %), And the absolute energy value at 100% is the same in all of FIGS. 3, 4, and 5 below.

On the other hand, for comparison, a metal vapor discharge lamp excluding tin iodide from Lamp A (Lamp B) and a metal vapor discharge lamp containing only magnesium iodide (Lamp C) were prepared and the output relative value of the emission spectrum was measured. Is shown in FIGS. 3 and 4.

As is clear from these figures, the metal vapor discharge lamp of the present invention (Lamp A) has a bright line spectrum of magnesium, particularly an effective wavelength, as compared with the metal vapor discharge lamps without addition of tin (Lamp B) and (Lamp C). It can be seen that the output relative value in the region 220 to 330 nm is increasing. Looking at the effect of tin by comparing FIG. 2 with FIG. 3 and FIG. 4, it can be seen that
As is clear from the figure, the emission line spectrum of magnesium increases, and it is understood that tin contributes to magnesium as a light emission auxiliary component.

Furthermore, the present invention is 35% more efficient than conventional mercury lamps (see FIG. 5).
Since the output relative value in the harmful spectral region of 0 nm or more can be drastically reduced, a metal vapor discharge lamp suitable for resist hardening can be provided.

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

As described above, the metal vapor discharge lamp of the present invention is a metal vapor discharge lamp in which magnesium and halogen are enclosed in a mercury-free arc tube, and tin and 5-300T
By enclosing oor xenon gas, it is possible to provide a light source that efficiently emits ultraviolet light in the wavelength range of 220 to 330 nm, which is effective for photochemical reaction, particularly for resist hardening.

[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, and FIG. 2 is a graph showing a relationship with a spectral distribution of an emission spectrum in the metal vapor discharge lamp of the present invention.
3 and 4 are graphs showing the spectral distribution of the emission spectrum of a conventional metal vapor discharge lamp, and FIG. 5 is a graph showing the spectral distribution of the emission spectrum of a conventional high pressure mercury 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 a mercury-free arc tube is filled with magnesium and a halogen, wherein tin and xenon gas of 5 to 300 Toor are filled. .