Device and method for adjusting ring cavity of excimer laser device

Abstract

The invention belongs to the technical field of excimer lasers and provides a device and a method for adjusting a ring cavity of an excimer laser device. The device comprises a reference light source, reflecting mirrors, a small-hole diaphragm and a screen, wherein the reference light source is used for producing reference light beams for calibration. The method is particularly applicable to a ring cavity adjustment reference light and excimer laser coaxial method. According to the method, a discharging chamber optical axis position can be determined with fluorescent light spot centers of a discharging chamber outside two sealing windows serving as references, and two reflecting mirrors inside the ring cavity are adjusted to enable reference light to circle the ring cavity by one circle and then coincide with a far point light spot at a near point with secondary reflection light of the reference light which just enters a coupling mirror, so that a cavity body of the ring cavity of the excimer laser device can be adjusted. According to the method and the device, limitations of traditional methods are broken through, the adjustment of the ring cavity is simplified into the adjustment of coincidence of two light beams outside the cavity, the adjustment precision is high, sealing windows are not required to be removed, additional measurement instruments are not required, and the operation is simple.

Description

technical field [0001] The invention belongs to the field of excimer laser technology and provides an excimer laser ring cavity adjustment device and method. Background technique [0002] ArF excimer lasers are still the main light source for lithography machines. With the continuous reduction of lithography nodes, it is difficult for single-cavity excimer lasers to meet the requirements of lithography for light source power and line width at the same time. Foreign companies first adopted MOPA (Master oscillator power amplifier) ​​technology to solve this contradiction. However, this technology requires a large energy discharge excitation, which makes the life of the MO (Master oscillator) cavity significantly lower. In addition, the output of the amplifier cavity is greatly affected by the synchronous jitter of MO and PA (power amplifier). Cymer has developed the Recirculating ring technology to solve the problems caused by the MOPA technology. The improved structure ma...

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Problems solved by technology

However, for the excimer laser ring cavity, the cross-sectional area of ​​the discharge area is small, and the traditional method to determine the optical axis position will cause a large error

On the other hand, the excimer laser discharge cavity contains strong corrosive gases such as halogens, and the sealed window is generally not disassembled at will. The mirror is generally a multi-layer dielectric film, which only has high reflection for a specific laser wavelength. Both the window and the mirror are The reference light has a large loss, and the reference light can hardly find the position of the beam after it propagates in the ring cavity and is reflected by the coupling mirror.

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