JPH0452271A - Laser vapor deposition device - Google Patents

Abstract

PURPOSE:To occasionally monitor a laser power and to uniformly consume a target by extending the distance at which the target moves back and forth to remove the target once from the laser beam. CONSTITUTION:The distance at which the target 4 moves back and forth is extended to remove the target once from the irradiation with the laser. The target 4 is not irradiated with the laser and the vapor deposition does not progress while the target 4 exists at the left end of the forward and backward motion. The laser is absorbed in a power monitor 11 behind the target 4 and the output thereof is recorded. The target 4 moves rightward while rotating and the vapor deposition is started simultaneously when the target begins to be irradiated with the laser beam 8. The laser power is not detected when the evaporation starts. The laser power can be detected again while the target 4 exists at the right end. The detection of the laser power is not required to be executed at every inversion of the target 4 and may be executed at every proper interval.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for forming a thin film using a laser as a heat source, and particularly relates to an improvement in the method of moving a target.

[Conventional technology]

FIG. 4 is a sectional view showing a conventional laser evaporation apparatus disclosed in, for example, Japanese Patent Application No. 1-118199.

In the figure, a vacuum chamber 2 equipped with a laser transmission window 1 is equipped with evacuation equipment 3. 4 is a cylindrical target made of a material on which film formation is desired, for example, ceramics such as A110:+S i O□. A heater 6 for heating is attached to the back of the substrate 5. 7 is a laser oscillator that emits a laser beam 8 that serves as a heat source;
If Affi, O, is used as a target, a Cot laser oscillator is suitable. 9 is a mirror that changes the optical path of the laser beam 8; 10 is a focusing lens.

Next, the operation will be explained.

The pressure inside the vacuum chamber 2 is normally reduced to 10-
It is kept in the range of 4 to 10-' Torr.

The target 4 repeats rotation and reciprocation as shown in FIG. As you can see from the figure, the distance of the reciprocating movement is set to be slightly narrower than the width of the target.

The speed of rotation and reciprocation is determined by the melting point of the target used,
It varies greatly depending on the laser power, but for example, when the target is 5iOz and the power is 30W, each speed is 5 rpm.
, is a relatively small value of about 50 mm/min.

A laser beam 8 emitted from an oscillator 7 is focused by a focusing lens 10, passes through a transmission window 1, and then irradiates a target 4. The beam diameter on the Tarquent 4 varies depending on the focal length f of the lens 10, but for example, when f=400 mm, it is about 1 mm.

Because the spot diameter is small in this way, a very large power density is generated at the laser irradiation point, and SiO2 and AAz03
High-melting-point substances such as substances easily melt and become vapor and scatter. Among the scattered vapors, those that fly to the substrate 5 are condensed to form a thin film.

If evaporation occurs, the number of points will gradually decrease, but since the target 4 is rotating and reciprocating, only the - points will not be consumed. Furthermore, since the distance over which the target reciprocates is narrower than the width of the target, the target is constantly irradiated with the laser, and the deposition progresses without any trace.

[Problem to be solved by the invention]

Incidentally, although the evaporated particles from the target 4 are not large in quantity, they adhere to the transmission window 1, so if evaporation is performed for a long time, the particles absorbed by the deposits will actually contribute to the evaporation. The available laser power is reduced. Along with this, the deposition rate also decreases.

Therefore, in order to keep the evaporation rate constant, it is necessary to constantly monitor the laser power, but with conventional equipment, the laser constantly irradiates the target, making it impossible to monitor. Ta.

Furthermore, in order to prevent the vapor deposition from being cut, both ends of the target 4 are not irradiated with the laser. For this reason, target 4
As shown in Fig. 6, the number of targets decreased like a pincushion, and some expensive targets had to be discarded without being used.

This invention was made to solve the above-mentioned problems, and aims to provide a laser evaporation apparatus that can monitor the laser power that actually contributes to evaporation at any time and that can consume the target uniformly.

[Means to solve the problem]

In the laser vapor deposition apparatus according to the present invention, the distance over which the target reciprocates is extended so that the target always comes off the laser once when the target moves back and forth.

[Effect]

In this invention, since there is always a time when the laser does not irradiate the target, it is possible to monitor the laser power at any time.

〔Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing only important parts of a laser deposition apparatus according to an embodiment of the present invention.

In the figure, reference numeral 11 indicates a power monitor provided on the optical path of the laser beam 8 behind the target 4.

Next, the operation will be explained.

The principle of vapor deposition is exactly the same as in the conventional example.

The target 4 indicated by a solid line is at the left end of the reciprocating motion. In this state, vapor deposition does not proceed because the target is not irradiated with the laser. Instead, the laser is absorbed by a power monitor and its output is recorded. It usually takes several seconds for the output of the power monitor to show a steady value.

The target at the left end rotates and sequentially moves to the right, and vapor deposition begins as soon as it starts to be hit by the laser beam 8. Once deposition begins, laser power is no longer detected.

The target 4° indicated by the dotted line indicates that the target is at the right end of the reciprocating motion. In this state, laser power can be detected again. Thereafter, the target turns around and repeats the reciprocating motion.

- The time required for a round trip depends on the width of the target 4 and the reciprocating speed. For example, if the width is 50 si and the speed is 50 km/min, one round trip will take about 2 minutes.

As mentioned above, the time required to detect the power is about 10 seconds, so the time during which vapor deposition is not performed is only about a few percent, so the decrease in productivity caused by the lack of vapor deposition is not so large.

FIG. 2 shows the shape of the target obtained after long-term deposition. Since the laser scans the entire target surface, it is consumed evenly, and there is no waste as in the conventional method.

In the above embodiment, the case where the moving speed is constant has been described, but the speed when the laser is irradiating the target and the speed when the laser is not irradiating the target need not be constant.

By slowing the irradiation speed or increasing the irradiation speed when not irradiating, it is possible to suppress the decrease in productivity caused by the slow progress of vapor deposition.

Further, in order to detect whether or not the target is irradiated with the laser, the output of the power monitor 11 may be used, but the light emission generated during laser irradiation may be detected with a photodetector.

FIG. 3 shows an example in which a photodiode is used as a photodetector. In order to prevent vapor from adhering to the detector, it is preferable to place the detector as low as possible within the range where luminescence can be observed.

If the edge of the target remained as in the conventional device, the detector would be placed on the right or left side in Figure 3 (there was a risk that the emission would gradually stop being observed, but with this method, the edge does not remain). There is no need to worry like this.

Needless to say, it is not necessary to detect the laser power every time the target is reversed, and it is sufficient to detect the laser power at appropriate intervals. When the laser power is not detected, the target can be instantly reversed as soon as the detector confirms that the laser is no longer irradiating the target. In this way, the drop in productivity becomes almost negligible.

Note that the present invention is not limited by the type of laser or target used, and similar effects can be achieved by a combination of a YAG laser or excimer laser and a superconducting material.

〔Effect of the invention〕

As described above, according to the laser vapor deposition apparatus according to the present invention, the apparatus is configured so that there is a time when the target is not irradiated with the laser, so the laser power can be monitored at any time, and the target can be used without wasting it. effective.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing the main parts of a laser evaporation apparatus according to an embodiment of the present invention, FIG. 2 is a plan view showing how the target is reduced in the embodiment of the present invention, and FIG. 3 is a diagram showing another embodiment of the present invention. FIGS. 4 and 5 are block diagrams showing an embodiment of the present invention, FIGS. 4 and 5 are block diagrams showing a conventional apparatus, and FIG. 6 is a plan view showing how targets are reduced in the conventional apparatus. In the figure, 4 is a target which is a vapor deposition material, and 7 is a laser oscillator. Note that the same reference numerals in the figures indicate the same or equivalent parts. Figure 1

Claims (1)

[Claims] (1) In an apparatus that performs vapor deposition by rotating and reciprocating a target made of a vapor deposition material and irradiating the target with a laser, the target is subjected to such a reciprocating movement that it always comes off the laser irradiation. A laser evaporation device characterized by: