JPH04216614A - Laser beam irradiation device - Google Patents

Abstract

PURPOSE:To manufacture the title laser irradiation device capable of irradiating a semiconductor with stable laser beams not to be affected by the oscillation of a movable part during the laser scanning step. CONSTITUTION:A stage whereon a galvanoscanner 6 as a movable part for laser scanning step and an ftheta lens 7 are arranged is mounted on a stage rack 15 provided independently of another stage rack 14 whereon a semiconductor wafer 9 etc., and other parts are arranged to be composed so that the oscillation may not be transferred between the two racks 14 and 15 from each other.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam irradiation device for processing using laser light, and more particularly to a laser beam irradiation device applied to the manufacture of semiconductor devices.

0002

[Prior Art] So-called SOI (Silicon OnIns), which forms a single crystal semiconductor layer on an insulator, has conventionally been used.
ulator) technology has been developed. Among these, laser annealing technology, which melts polycrystalline silicon deposited on an insulator using narrowly focused laser light and turns it into a single crystal, is
Since it is possible to keep the temperature of the semiconductor substrate low during processing, it has been developed as an SOI formation technology for three-dimensional circuit elements. Furthermore, laser annealing technology is also applied to activation of ion-implanted impurities and laser CVD (chemical vapor deposition) technology, which selectively forms a film on a semiconductor substrate using laser light.

FIG. 2 shows a block diagram of a conventional laser annealing apparatus. In FIG. 2, 1 is a 20W output argon ion laser oscillator (hereinafter referred to as a laser), 2 is a light blocking shutter (hereinafter referred to as a shutter) provided on the optical path of the laser beam, and 2b is a rotating mirror type. It is a galvano scanner that takes only 10 msec to rotate through an angle of about 20 degrees. Further, 2a is a cooling unit that absorbs the laser beam reflected by the galvano scanner 2b and cools it by forced cooling, and is made of an aluminum heat sink treated with black alumite, and turns the laser beam oscillated from the laser 1 on and off at high speed. can do. 3 is a beam expander that exists to expand the diameter of the laser beam that was not blocked by the shutter 2 to about 3 times, making it easier to narrow down the beam diameter of the laser beam during processing, and is composed of two lenses. has been done. 4a to 4d are fixed mirrors. 5 is λ/2
It is a wavelength plate, and by rotating it as an optical axis, the power of the laser light passing through it is adjusted. 6 is a galvano scanner, which is a rotating mirror for scanning the laser beam in the λ direction. 7 is an fθ lens, which directs the laser beam to 5
This lens focuses the beam to a diameter of 0 μm to 100 μm, and is set so that the beam diameter and scanning speed do not change due to scanning in the X direction. 8 is galvano scanner 6 and f
This is a stage on which a θ lens 7 is installed, and is a single-axis precision stage movable in the Y-axis direction. 9 is a semiconductor wafer, and 10 is a stand for holding the semiconductor wafer 9. Usually, the semiconductor wafer 9 is held on the stand 10 by a vacuum chuck. 11 is an infrared lamp, and installation stand 1
It is provided to heat the semiconductor wafer 9 held at zero temperature to a temperature of 400 to 500°C. Reference numeral 12 denotes a chamber that surrounds the semiconductor wafer 9, the installation stand 10, and the infrared lamp 11. Inside the chamber 12, an N2 gas introduction pipe 13 is provided to prevent the surface of the semiconductor wafer 9 from being oxidized during laser beam irradiation. The inside is filled with N2 atmosphere.

Next, the operation will be explained. A laser beam oscillated from a laser 1 is expanded into a beam with a diameter of about 10 mm by a beam expander 3, adjusted to an appropriate power by a λ/2 wavelength plate 5, and then guided to a galvano scanner 6. The laser beam reflected by the galvano scanner 6 is narrowed down to a diameter of 100 μm by the fθ lens 7 and
The semiconductor wafer 9 heated to 0° C. is irradiated. As the galvano scanner 6 rotates, the laser beam is directed onto the semiconductor wafer 9.
A predetermined area is scanned in the X direction. When one scan is completed, the shutter 2 is closed (the galvano shutter 2b rotates and the laser beam is applied to the cooling unit 2a to block the optical path). While the shutter 2 is operating and cutting off the laser beam, the galvano scanner 6 is returned to the initial scanning position, and the stage 8 is moved by 80 μm in the Y direction. After the stage 8 moves in the Y direction and comes to a complete standstill, the shutter 2 opens again, the galvano scanner 6 rotates, and the second laser beam scan begins. In this way, the entire area of the semiconductor wafer 9 is irradiated with laser light while scanning, and processing is performed.

[0005]

In order to manufacture SOI (three-dimensional circuit elements) at a high yield, it is necessary that beam scanning be uniform and that laser power be stable during processing. However, in the conventional laser beam irradiation device, all the movable parts for scanning the laser beam, including the stage 8 and the galvano scanner 6,
It was installed on a single pedestal (vibration isolator 14). Therefore, there is a problem in that laser scanning is affected by vibrations caused by the movement of the movable part for scanning, causing meandering of the laser beam and non-uniformity in scanning speed. Furthermore, when this vibration is transmitted to the laser, there is a problem in that the output of the laser beam fluctuates.

The present invention was made to solve the above-mentioned problems, and provides a laser that can stably irradiate laser beams without being affected by vibrations of the movable parts during laser beam scanning. The purpose is to provide a light irradiation device.

[0007]

[Means for Solving the Problems] In the laser beam irradiation device according to the present invention, the movable part for laser beam scanning and other parts are installed on independent frames, and vibrations are not transmitted between the two frames. This is what I did.

[0008]

[Operation] In the laser light irradiation device of the present invention,
By installing the movable part for laser beam scanning and other parts on independent mounts and preventing vibrations from being transmitted between the two mounts, it is possible to stably irradiate the sample with laser light.

[0009]

[Embodiment] FIG. 1 is a block diagram of a laser beam irradiation device according to an embodiment of the present invention, in which 1 is a laser, 2 is a shutter,
2a is a cooling unit, 2b is a galvano scanner, 3 is a beam expander, 4a, 4b, 4c, 4d are fixed mirrors, 5 is a λ/2 wavelength plate, 6 is a galvano scanner, 7 is an fθ lens, 8 is a stage, 9 is a semiconductor wafer, 10 is an installation stand, 1
1 is an infrared lamp, 12 is a chamber, 13a and 13b are N2 gas introduction pipes, 13c and 13d are exhaust pipes, 14 is a pedestal, and 15 is a stage pedestal on which the stage 8 is mounted. The operation of each component is exactly the same as that of the conventional laser beam irradiation device. This embodiment is characterized in that a stage pedestal 15 on which the stage 8 that moves during laser scanning is placed and a pedestal 14 on which other parts are placed are provided independently.

Next, the operation will be explained. Since the series of operations of the laser beam irradiation device is exactly the same as that explained in the conventional example, the explanation thereof will be omitted. In this embodiment, a stage pedestal 15 formed independently of the pedestal 14 is moved in the Y direction to scan the entire area of the semiconductor wafer 9 with laser light. The relative position (relative height) between the pedestal 14 and the stage pedestal 15 is controlled to be within ±2 μm using a relative position detector and a computer (not shown).

[0011] In this embodiment, the movable part for laser beam scanning and other parts are installed on independent frames, so that the vibrations of each part do not affect each other.
The laser beam can be stably irradiated onto the sample regardless of the vibration of the stage frame, and the beam can be scanned stably.

0012

Effects of the Invention As described above, according to the laser beam irradiation device according to the present invention, the movable part for laser beam scanning and other parts are installed on independent frames, and the vibrations during laser beam scanning can be applied to the laser beam source. Since the laser beam is prevented from being transmitted to the sample mounting table, stable laser beam irradiation is possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a laser beam irradiation device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional laser beam irradiation device.

[Explanation of symbols]

1 Laser 2 Shutter 2a Cooling section 2b Galvano scanner 3 Beam expander 4a-4d Fixed mirror 5 λ/2 wavelength plate 6 Galvano scanner 7 fθ lens 8 Stage 9 Semiconductor wafer 10 Installation stand 11 Infrared lamp 12 Chamber 13 N2 gas introduction pipe 14 Mount 15 Stage mount

Claims (1)

[Claims] 1. A laser beam irradiation device that processes the substrate by scanning and irradiating a portion of the substrate with a laser beam, the substrate being processed, a light source section for laser light, and a fixed optical system. It has a first pedestal on which the system is installed, and a second pedestal on which a movable part for scanning the laser beam is installed, and the first and second pedestals are installed so that vibrations are not transmitted to each other. A laser beam irradiation device characterized by: