JP2000261074A - Ultraviolet laser system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet laser system, in which a xenon gas can be supplied efficiently to a chamber without remodeling an already existing laser gas supplying facility, when the burst characteristic and spike characteristic of the laser system are improved by adding a trace amount of xenon gas to the gas for excimer laser. SOLUTION: A mixing pipeline, which is partitioned by valves 14-16, is provided on the piping from a chamber 10 to gas cylinders 20 and 21 for excimer laser and is connected to a Xe(xenon) gas cylinder 22. Then a trace amount of Xe gas is additionally supplied to the chamber 10, by controlling the gas discharge through the means of a gas exhaust module 13 and the opening/closing of the valves 14-16 by means of a gas controller 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for adding a very small amount of xenon gas to an ultraviolet laser gas introduced into a chamber.
The present invention relates to an ultraviolet laser device that excites an ultraviolet laser gas by pulse oscillation in the chamber to oscillate a pulse laser, and in particular, efficiently supplies xenon gas into the chamber without modifying existing laser gas supply equipment. The present invention relates to an ultraviolet laser device.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor exposure apparatus using an ultraviolet laser apparatus such as an excimer laser apparatus as a light source, exposure of an IC chip on a semiconductor wafer is performed by repeating exposure and stage movement alternately. A burst operation in which a continuous pulse oscillation operation in which laser light is continuously pulsed for a predetermined number of times and an oscillation pause in which pulse oscillation is suspended for a predetermined time is performed.

However, when such a burst operation is performed,
Burst characteristics and spike characteristics in which energy gradually decreases occur, and the laser output output from the excimer laser device fluctuates in energy for each burst, resulting in a problem that the exposure amount varies.

[0004] For this reason, the applicant of the present invention has disclosed in Japanese Patent Application No.
Japanese Patent No. -23709 proposes a technique for improving a variation in exposure amount due to such burst characteristics and spike characteristics by adding a small amount of xenon gas to an ultraviolet laser gas in a chamber.

[0005]

However, in this prior art, a xenon gas cylinder for supplying xenon gas into a chamber is provided separately from a gas cylinder for an ultraviolet laser, and the xenon gas is supplied to the chamber through a path completely different from the supply path of the ultraviolet laser gas. It is not efficient because it needs to be supplied inside.

In particular, at the site where an excimer laser is installed, only the laser gas supply equipment such as a gas cylinder for an ultraviolet laser, which is originally required, is provided. Therefore, such equipment is only required to supply xenon gas into the chamber. Renovating is not efficient.

[0007] From these facts, when burst characteristics and spike characteristics of an ultraviolet laser device are eliminated by adding a small amount of xenon gas, how efficiently xenon gas is introduced into the chamber without modifying existing laser gas supply equipment. Supply is an extremely important issue.

Accordingly, the present invention solves the above-mentioned problems and efficiently eliminates the burst characteristics and spike characteristics of an ultraviolet laser device without modifying existing laser gas supply equipment when a small amount of xenon gas is added. It is an object to provide an ultraviolet laser device capable of supplying xenon gas into a chamber.

[0009]

In order to achieve the above object, an ultraviolet laser apparatus according to the first aspect of the present invention adds a very small amount of xenon gas to an ultraviolet laser gas introduced into a chamber. An ultraviolet laser device that excites the ultraviolet laser gas by pulse oscillation and oscillates a pulse laser, wherein a xenon gas cylinder enclosing the xenon gas, an ultraviolet laser gas cylinder enclosing the ultraviolet laser gas, An ultraviolet laser gas supply pipe connecting the chamber with the ultraviolet laser gas cylinder, wherein a predetermined position of the ultraviolet laser gas supply pipe and the xenon gas cylinder are connected via a xenon gas pipe. I do.

In the present invention, since a predetermined position of the ultraviolet laser gas supply pipe connecting the ultraviolet laser gas cylinder and the chamber is connected to the xenon gas cylinder via the xenon gas pipe, the existing laser gas supply equipment is used. Without modification, xenon gas can be easily supplied into the chamber. Since the added xenon gas is put into the inside of a trace volume pipe and the xenon gas is quantified using a pressure gauge, the xenon gas can be easily and accurately added to the laser gas. If a xenon gas cylinder is installed near the chamber, the valve can be closed at the time of chamber replacement, and the xenon gas cylinder can be replaced at the same time by removing the pipe joint. The risk of contamination with impurity gas is also reduced.

According to a second aspect of the present invention, in the ultraviolet laser device, a first valve and a second valve are provided on the ultraviolet laser gas supply pipe, and the first valve and the second valve are provided.
A third valve is disposed on a mixing pipe formed by the above-mentioned valve and a pipe therebetween, and the third valve is connected to the xenon gas cylinder and the xenon gas pipe.

According to the present invention, a third valve is provided on a mixing pipe formed by the first valve, the second valve, and a pipe therebetween, and the third valve and the xenon gas cylinder are connected to each other for xenon gas. Since it is configured to be connected by a pipe, there is an effect that xenon gas or ultraviolet laser gas can be easily introduced into the chamber only by opening and closing the first to third valves.

According to a third aspect of the present invention, there is provided an ultraviolet laser apparatus, wherein the second valve and the third valve located on the side of the ultraviolet laser gas cylinder of the mixing pipe are closed, and a chamber of the mixing pipe is provided. After the chamber is evacuated while the first valve located on the side is opened, the third valve is opened while closing the first valve to supply xenon gas into the mixing pipe, and the mixing is performed. If it is measured that the gas pressure on the pipe has reached a predetermined gas pressure, the third
And closing the first valve and the second valve.

According to the present invention, the second valve and the third valve located on the side of the ultraviolet laser gas cylinder of the mixing pipe are closed, and the first valve located on the chamber side of the mixing pipe is opened. After evacuating the chamber, the first
If the third valve is released while closing the valve and xenon gas is supplied into the mixing pipe, and it is measured that the gas pressure on the mixing pipe has reached a predetermined gas pressure, the third valve Is closed and the first valve and the second valve are opened, so that the xenon gas or the ultraviolet laser gas can be more easily supplied to the chamber by using the vacuum of the chamber and the opening and closing of the first to third valves. It has the effect of being able to be introduced inside.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the ultraviolet laser device according to the present invention will be described below in detail with reference to the accompanying drawings. Hereinafter, a case where the present invention is applied to an excimer laser device will be described.

FIG. 1 is a block diagram showing the overall configuration of the excimer laser device used in the first embodiment.

The excimer laser device shown in FIG. 1 comprises a buffer gas such as Ne, a rare gas such as Ar or Kr,
A small amount of xenon (Xe) gas is added to an excimer laser gas composed of a halogen gas such as 2 and sealed in the chamber 10, and the excimer laser gas is excited by a discharge (not shown) between discharge electrodes to generate a laser pulse. It is a device for performing. The reason why the xenon gas was introduced into the chamber 10 instead of simply introducing only the excimer laser gas into the chamber 10 is that the presence of the xenon gas improves the burst characteristics and spike characteristics of the excimer laser output. Because it is done.

Here, this excimer laser device is a Xe
Instead of connecting the gas cylinder 22 directly to the chamber 10,
The Xe gas cylinder 22 is connected to a valve 16 of a pipe (this pipe is called a “mixing pipe”) partitioned by three valves 14 to 16 (hereinafter, referred to as a first valve, a second valve, and a third valve). Is characterized by the fact that they are combined.

That is, conventionally, a laser gas supply facility is provided at the site, but if the laser gas supply facility is modified so that the excimer gas can be supplied from the Xe gas cylinder 22 into the chamber 10, the existing facility will be greatly improved. As a result, it is not efficient. In particular, there are laser devices that do not require the addition of xenon gas. Therefore, the gas supply equipment at the site where optical processing using a laser is performed only for the addition of xenon gas (such as a clean room where a semiconductor wafer exposure stepper is installed) is significantly increased. It is not realistic to renovate.

Therefore, in the present embodiment, xenon gas can be introduced into the chamber 10 without modifying the laser gas supply equipment and without increasing the number of piping ports provided in the chamber 10.

As shown in FIG. 1, this excimer laser device will be described using an ArF excimer laser as an example.
2, a gas exhaust module 13, and valves 14 to 16
, Pressure gauge 17, pipe joint 18, and air supply module 1
9, Ar / Ne mixed gas cylinder 20, Ar / Ne /
An F2 mixed gas cylinder 21, a Xe gas cylinder 22, and a gas controller 23 are provided.

The chamber 10 is an encapsulation medium for encapsulating a gas for excimer laser composed of Ne gas, Ar gas and F2 gas by adding a very small amount of xenon gas. And is formed by a prism beam expander or grating (not shown). In addition, the partially transmitting mirror 1
Reference numeral 2 denotes a mirror that transmits and outputs only a part of the oscillation laser and returns another part into the chamber 10.

The gas exhaust module 13 is provided in the chamber 10
A module that exhausts gas inside to the outside.
Reference numerals 4 to 16 are provided on pipes from the chamber 10 to each gas cylinder.

The pressure gauge 17 is a measuring device for measuring the pressure in the mixing pipe separated by the valves 14 to 16 and the pressure in the chamber 10. The pipe joint 18 is used to connect the laser gas supply equipment and the pipe toward the chamber 10. It is a connecting part to be connected.

The air supply module 19 is a module for controlling the supply amount of the Ar / Ne gas in the Ar / Ne mixed gas cylinder 20 and the Ar / Ne / F2 gas in the Ar / Ne / F2 mixed gas cylinder 21 to the pipe. .

The Ar / Ne mixed gas cylinder 20 is a gas cylinder for storing a mixed gas of argon and neon.
The / Ne / F2 mixed gas cylinder 21 is a gas cylinder that stores a mixed gas of argon, neon, and fluorine.
The gas cylinder 22 is a small gas cylinder that stores xenon gas.

The gas controller 23 is a control unit for controlling the exhaust by the gas exhaust module 13 and controlling the opening and closing of the valves 14 to 16.

As described above, in this excimer laser apparatus, the Xe gas cylinder 22 is connected to the mixing pipe, and the gas controller 23 controls the gas exhaust module 13 and the valves 14 to 16 to add a small amount of xenon gas to the excimer laser gas. It is configured to do.

Next, a control procedure of the gas exhaust module 13 and the valves 14 to 16 by the gas controller 23 shown in FIG. 1 will be described.

FIG. 2 shows the gas controller 23 shown in FIG.
Is a flowchart showing a control procedure of the gas exhaust module 13 and the valves 14 to 16 according to the first embodiment.

As shown in the figure, the gas controller 23 first opens the valve 14, closes the valves 15 and 16 (step 201), and then exhausts the inside of the chamber 10 by the gas exhaust module 13 (step 201). 2
02).

The gas exhaust module 13 exhausts the gas in the mixing pipe as well as in the chamber 10, so that the chamber 10 and the mixing pipe are almost in a vacuum state.

When the valve 14 is closed and the valve 16 is opened (steps 203 to 204), the Xe gas cylinder 22 is opened.
The xenon gas in the Xe gas cylinder 22 flows into the mixing pipe due to the gas pressure and the vacuum in the mixing pipe.

Thereafter, the gas pressure in the mixing pipe is measured by a pressure gauge 17, and when the measured value of the pressure gauge 17 exceeds a predetermined target value (step 205), the valve 16 is closed and the xenon gas is removed. Stop supplying (Step 20)
6).

When the valve 14 is opened in this state, the xenon gas in the mixing pipe is introduced into the chamber 10 due to the vacuum in the chamber 10, and the xenon gas is supplied to the chamber 1.
It is spread into 0 (step 207).

Thereafter, when the valve 15 is opened to introduce the excimer laser gas supplied from the air supply module 19 into the chamber 10 (step 208), the diffused xenon gas is added to the excimer laser gas.

As described above, in the present embodiment,
A mixing pipe partitioned by valves 14 to 16 is provided on a pipe from the chamber 10 to the gas cylinders 20 and 21 for the excimer laser, and the mixing pipe and the Xe gas cylinder 22 are connected to each other. Gas exhaust and valve 14-1
By controlling the opening and closing of the excimer laser gas, a small amount of xenon gas can be added to the gas for the excimer laser. Can be added in a small amount.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an excimer laser device according to a first embodiment.

FIG. 2 is a flowchart showing a control procedure of the gas controller shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Chamber 11 Band narrowing unit 12 Partial transmission mirror 13 Gas exhaust module 14, 15, 16 Valve 17 Pressure gauge 18 Piping joint 19 Air supply module 20 Ar / Ne mixed gas cylinder 21 Ar / Ne / F2 mixed gas cylinder 22 Xe gas cylinder 23 Gas controller

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Katsuchi Terashima 1200 Manda, Hiratsuka-shi, Kanagawa F-term in the Komatsu Ltd. Research Laboratory 5F071 AA06 BB01 FF09 JJ05

Claims (3)

[Claims] 1. An ultraviolet laser device, wherein a very small amount of xenon gas is added to an ultraviolet laser gas introduced into a chamber, and the ultraviolet laser gas is excited by pulse oscillation in the chamber to oscillate a pulse laser. A xenon gas cylinder containing xenon gas, an ultraviolet laser gas cylinder containing the ultraviolet laser gas, and an ultraviolet laser gas supply pipe connecting the ultraviolet laser gas cylinder and the chamber. An ultraviolet laser apparatus, wherein a predetermined position of a pipe and the xenon gas cylinder are connected via a xenon gas pipe. 2. A first valve and a second valve are provided on the ultraviolet laser gas supply pipe, and a first valve and a second valve are provided on a mixing pipe formed by the first valve, the second valve, and a pipe between them. 3. The ultraviolet laser device according to claim 1, wherein a third valve is provided, and the third valve and the xenon gas cylinder are connected by the xenon gas pipe. 3. A state in which the second valve and the third valve located on the side of the ultraviolet laser gas cylinder of the mixing pipe are closed, and the first valve located on the chamber side of the mixing pipe is opened. After the chamber is evacuated, the third valve is released while closing the first valve to supply xenon gas into the mixing pipe, and the gas pressure on the mixing pipe becomes a predetermined gas pressure. 3. The ultraviolet laser device according to claim 2, wherein when the measurement is performed, the third valve is closed and the first valve and the second valve are opened. 4.