JPS63229412A - Correcting device for optical path position - Google Patents

Abstract

PURPOSE:To eliminate the need for troublesome adjusting operation and to correct a shift in optical path position automatically by providing a means which detects the shift from a specific optical path position and controlling the attitude of a mirror system according to the detected shift so that the shift is canceled. CONSTITUTION:A control system 17 computes a control variable required to the shift in the optical path position of a laser beam according to an electric signal corresponding to the optical path position shift detected by a horizontal shift detector 15 and a vertical shift detector 16, and outputs the variable as a control signal, and a driving system 18 has four motors coupled with the horizontal main shaft and vertical main shaft of mirrors 2 and 3 and controls the attitudes of the mirrors 2 and 3 in response to the control signal from the control system 17 so as to cancel the optical path position shift. Consequently, the troublesome adjusting operation is made unnecessary to correct the shift in the optical path position automatically and an unexpected optical path position shift of the optical system is handled sufficiently.

Description

[Detailed Description of the Invention] [Summary] An optical path position correction device, which is a beam extractor disposed on an optical path between a mirror system and an irradiation system to extract a part of a light beam and reflect it in a predetermined direction. and means for receiving a portion of the reflected light beam and detecting deviation from a predetermined optical path position in the first and second directions in a plane perpendicular to the traveling direction of the light beam, By controlling the attitude of the mirror system based on the detected deviation so that the deviation is canceled out, complicated adjustment work is unnecessary and it is possible to deal with unpredictable deviations in the optical path position of the optical system. It is something to do.

[Industrial application field]

The present invention relates to an optical path position correction device, and more particularly to a device that automatically corrects a deviation in the optical path position in a device using an optical system, such as a laser annealing device used in semiconductor processing.

[Prior art and problems to be solved by the invention]

FIG. 3 schematically shows the configuration of a laser annealing apparatus as an example of a conventional type. In this device, a laser beam LB oscillated from a laser oscillator 31 is transmitted to a mirror 32.
and 33, the mirror 35 in the irradiation system 34
The sample, i.e., the wafer 3 on the stage 36, is
7, to recrystallize a predetermined portion of the wafer. In this case, since this predetermined portion is an extremely fine and small area, when irradiating the laser beam, the optical path, that is, the optical path from the output end of the laser oscillator 31 to the input end of the irradiation system 34, is set in advance to a predetermined optical path. Must be maintained accurately to pass position.

However, during use of the device, the optical path changes and the laser
The beam position may shift. The causes of deviation due to fluctuations in the optical path include: (1) deviation of the oscillation mirror in the laser oscillator 31 caused by heat, fluctuations in power supply voltage, vibration of the device itself, etc.; (2) deviation of the mirror caused by vibration of the device itself. 32.33 positional deviations are considered.

Conventionally, when the optical path position shifts, the mirrors 32 and 33
The optical path position was corrected by either slightly moving the pinhole and adjusting it by feel, or by visually adjusting the laser beam so that it passed through the pinhole. As described above, it is possible to correct the optical path position for deviations caused by vibrations of the apparatus itself, although the adjustment work is extremely complicated. However, it is difficult to deal with deviations caused by the laser oscillator itself due to heat, voltage fluctuations, etc. Additionally, the laser beams used in laser annealing equipment are extremely intense and can be dangerous to the eyes.

The above was explained using a laser annealing device as an example.
Generally, in a device using an optical system, in addition to deviations in the optical path position caused by vibrations of the device itself, there are also deviations in the optical path position caused by the light source itself, which cannot be adequately addressed by manual adjustment.

The present invention was created in view of the problems in the prior art described above, and an object of the present invention is to provide an optical path position correction device that can automatically correct deviations in optical path position without requiring complicated adjustment work. It is said that

[Means for solving problems]

The problems with the above-mentioned conventional technology are that the mirror system disposed on the optical path, the irradiation system that irradiates the object with the light beam reflected by the mirror system, and the light beam between the mirror system and the irradiation system. a beam extractor disposed on a road, which allows most of the light beam to pass through while extracting a part of the light beam and reflecting it in a predetermined direction; and a part of the light beam reflected by the beam extractor. means for detecting deviations from a predetermined optical path position in a first direction and a second direction in a plane perpendicular to the traveling direction of the light beam, and canceling the deviations based on the detected deviations; The problem is solved by providing an optical path position correcting device comprising means for controlling the attitude of the mirror system so as to correct the deviation of the optical path position.

[Effect]

According to the above-described configuration, the beam extraction means disposed on the optical path extracts a part of the light beam without interfering with the passage of the light beam, and the detection means extracts a part of the extracted light beam. Based on this, a deviation from a predetermined optical path position in a plane perpendicular to the traveling direction of the light beam is detected. This deviation is
a first direction (for example, horizontal direction) within the orthogonal plane;
and a second direction (for example, vertical direction).

Then, based on this detected deviation, the mirror system is attitude controlled so that the 8° deviation is canceled out.

In this way, the device of the present invention eliminates the need for complicated adjustment work and automatically corrects optical path position deviations, and can also adequately deal with unpredictable optical path position deviations in the optical system. It is something.

〔Example〕

FIG. 1 shows the configuration of an optical path position correction device as an embodiment of the present invention. In the figure, 1 is a laser oscillator;
2 is the laser beam LB emitted from the laser oscillator 1
3 is a mirror that reflects the laser beam LB reflected by the mirror 2 in a predetermined direction, and 4 is an irradiation system. The irradiation system 4 has a mirror 5 and has a function of causing most of the laser beam LB reflected by the mirror 3 to be reflected by the mirror 5 and irradiated onto the wafer 7 on the stage 6 . Furthermore, the mirrors 2 and 3 are each disposed rotatably around a vertical axis so that the laser beam can be scanned horizontally in a plane perpendicular to the direction in which the laser beam travels, and at the same time, the mirrors 2 and 3 are - It is rotatably arranged around a horizontal axis so that the laser beam can be scanned vertically within a plane perpendicular to the direction of beam travel.

Four beam extractors 11 to 14 are arranged on the optical path between the mirror 3 and the irradiation system 4, and each beam extractor extracts the laser beam without interfering with the passage of the laser beam. It has a function of reflecting a part of the beam (approximately 2 to 3% of the total beam amount, hereinafter referred to as LB2) in a predetermined direction. In this case, the beam extractors 11 and 13 are
It is arranged so as to reflect a portion of the laser beam horizontally in a plane perpendicular to the direction in which the laser beam travels.

Similarly, beam extractors 12 and 14 are arranged to reflect a portion of the laser beam vertically in a plane orthogonal to the direction of travel of the laser beam. Reference numeral 15 denotes a horizontal displacement detector, which has a group of pinholes (not shown) provided in a grid pattern at predetermined intervals, and detects a portion of the laser beam LB2 reflected by the beam extractors 11 and 13. detects which part of the pinhole group the laser beam has passed through, and thereby detects the laser beam from a predetermined optical path position.
It has a function of detecting the horizontal deviation of the beam and outputting an electrical signal corresponding to the detected amount. Reference numeral 16 denotes a vertical displacement detector, which similarly has a group of pinholes (not shown) provided in a grid pattern at predetermined intervals, and detects the laser beam reflected by the beam extractors 12 and 14. It detects which part of the pinhole group the part LB2 has passed through, and thereby the laser beam from a predetermined optical path position is detected.
It has a function of detecting the vertical deviation of the beam and outputting an electrical signal corresponding to the detected amount.

Reference numeral 17 denotes a control system, which performs control necessary to cancel the deviation based on electrical signals corresponding to deviations in the optical path position of the laser beam detected by the horizontal deviation detector 15 and the vertical deviation detector 16, respectively. It has the function of calculating the amount and outputting it as a control signal. Reference numeral 18 denotes a drive system, which is connected to the horizontal and vertical main axes of the mirrors 2 and 3, respectively.
It has a function of controlling the attitude of the mirrors 2 and 3 in response to a control signal from the control system 17 so that the optical path position shift is offset.

Next, an example of the optical path position correction method using the apparatus shown in FIG. 1 will be explained with reference to FIG. The example shown in FIG. 2 shows a case where a vertical optical path position shift is corrected. In the figure, P is the optical path position detected by the vertical shift detector 16 based on the part LB2 of the laser beam extracted by the beam extractor 12, and 22 is the laser beam position extracted by the beam extractor I4. The optical path position detected by the vertical deviation detector 16 based on the beam portion LB2, solid line Q
o indicates a regular optical path. Assume now that for some reason a positional shift of the laser beam occurs in the vertical direction and the optical path changes as shown by a broken line Q in the figure.

In this case, the magnitude of the deviation of the optical path position P1 from the normal optical path is ΔP l , and the magnitude of the deviation of the optical path position P2 from the normal optical path is ΔP2. When the vertical deviation detector 16 detects the deviations of ΔP1 and ΔP2, the control system 17 first calculates a control amount corresponding to one ΔP1, and the drive system 18 adjusts the deviation of ΔP to zero based on this control amount. The posture of the mirror 3 is controlled so that the In this case, the mirror 3 is controlled to rotate around the main axis in the horizontal direction. As a result, the optical path position is corrected as shown by the broken line Q2 in the figure.

Next, the control system 17 calculates a control amount corresponding to -(ΔP2-Δp+), and the drive system 18 calculates (ΔP2-Δp+) based on this control amount.
The mirror 2 is attitude controlled so that P2-ΔP+) becomes zero. In this case, the mirror 2 is controlled to rotate around the main axis in the horizontal direction. As a result, the optical path position is set to the solid line Q in the figure. amended as shown. However, in reality, some deviation occurs in the optical path value l P 1, so the drive system 18
further controls the attitude of the mirrors so that this deviation becomes zero, and thereafter the attitude control of mirrors 3 and 2 is repeated until the deviated optical path is completely defeated by the original optical path Qo.

The above-described correction method can be similarly applied to correction of optical path position shift in the horizontal direction. However, in this case, mirrors 2 and 3 are each controlled to rotate around a vertical main axis.

In this way, the correction of the vertical optical path position deviation and the correction of the horizontal optical path position deviation can be performed independently without interfering with each other.
It is extremely effective for beam annealing equipment.

〔Effect of the invention〕

As explained above, according to the optical path position correction device of the present invention, it is possible to automatically correct deviations in the optical path position without the need for complicated adjustment work, and it is also possible to correct deviations in the optical path position that cannot be predicted in the optical system. However, it can be dealt with adequately.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an optical path position correction device as an embodiment of the present invention, FIG. 2 is a diagram for explaining an example of a correction method using the device shown in FIG. 1, and FIG. 3 is an example of a conventional type. This is a schematic diagram of a laser annealing device as shown in FIG. (Explanation of symbols) 1...Laser oscillator, 2.3...Mirror, 4...
Irradiation system, 5...mirror, 6...stage,
7... Wafer, 11.12.13.14... Beam extractor, 15... Horizontal direction shift detector, 16... Vertical direction shift detector, 17... Control system, 18...・Drive system. Fig. 2 Schematic diagram of a conventional -911 laser annealing apparatus 34... Irradiation system 36... Stage 37... Wafer LB... Laser beam

Claims (1)

[Scope of Claims] A mirror system (2, 3) disposed on an optical path, an irradiation system (4) that irradiates a target object (7) with a light beam reflected by the mirror system, and the mirror system. and the irradiation system, and allows most of the light beam to pass through, while extracting a part of the light beam and reflecting it in a predetermined direction.
, 12, 13, 14), and predetermined optical path positions in a first direction and a second direction in a plane that receives a portion of the light beam reflected by the beam extraction means and is orthogonal to the traveling direction of the light beam. means (15,
16); and means (17, 18) for correcting a deviation in the optical path position by controlling the attitude of the mirror system so that the deviation is offset based on the detected deviation. Device.