JPH0518780U - Laser beam positioning device - Google Patents

Abstract

(57) [Abstract] [Purpose] Correct the positional deviation of the laser beam accurately without deteriorating the processing capability. [Configuration] Laser beam emitted from the laser oscillator 1
The light intensity of 100 is weakened by the optical attenuator 2 so that the sample 6 is not processed. The laser beam 100 whose light intensity has been weakened by the optical attenuator 2 passes through the scanning mechanism 4 and the objective lens 5 and the sample 6
Irradiated on. The reflected light of the laser beam 100 from the sample 6 is detected by the TV camera 9 and sent to the image processing apparatus 10 as an image signal. The image processing device 10 processes the image signal from the TV camera 9 by pattern recognition, and obtains the deviation amount of the irradiation position of the laser beam 100. The controller 12 controls the drive device 7 based on the shift amount obtained by the image processing device 10.

Description

[Detailed description of the device]

[0001]

【Technical field】

 The present invention relates to a laser beam positioning apparatus, and more particularly, to a method for correcting a deviation of an irradiation position due to a laser beam axis deviation in a laser processing apparatus.

[0002]

[Prior art]

 Conventionally, in a laser processing apparatus, when irradiating a laser beam on a small-sized workpiece, the irradiation position of the laser beam is generally corrected by some method.

As a method of this correction, first, an image processing device is added to the observation optical system attached to the processing optical system, and the image processing device is made to process the image signal from the TV camera of the observation optical system to be processed. There is a method of correcting the deviation of the irradiation position of the laser beam with respect to the pattern.

There is also a so-called edge sensing method in which the area including the pattern to be processed is scanned with a laser beam used for processing and the position of the true pattern to be processed is detected by detecting a change in reflected light. ..

Further, so-called teaching, in which the operator of the apparatus adjusts the crosshairs indicating the laser irradiation position to the pattern to be processed while looking at the TV screen of the observation optical system before actually performing the processing. There is also a method.

The above-mentioned first and third methods are the reference position designed to emit the laser beam in the laser beam positioning apparatus, generally the relative displacement between the center of the objective lens and the pattern to be processed. Is intended to be corrected. However, if the laser beam deviates from the center of the objective lens, it does not mean that the positional deviation has been corrected. The above method is sufficient if the size of the pattern to be processed is about 1 mm or more and the positioning accuracy of the positioning device is about 100 μm.

On the other hand, if the dimension and position accuracy are smaller than this, for example, in a device for processing a thin film pattern, the size of the pattern to be processed is 100 μm or less and the positioning accuracy of the positioning device is 5 μm or less. It is not enough to correct the relative positional deviation between the laser beam emitting position and the pattern to be processed in the design of the objective lens, and it is necessary to correct the actual positional deviation from the laser beam emitting position. This is because the laser beam moves due to mechanical deformation such as thermal expansion of the optical system mechanism section including the objective lens.

The positional deviation of the laser beam on the sample surface due to the movement of the laser beam varies depending on the focal length of the object lens, the structure and material of the mechanical part constituting the optical system, etc., but is generally several μm to several tens μm. There may be deviation. This positional deviation is too large for processing a 100 μm pattern, for example, and the first and third methods described above correct this positional deviation, that is, the deviation of the laser beam from the center of the objective lens. There is a problem that you can not.

In the second method described above, since the edge of the pattern to be processed is sensed by the laser beam that has passed through the objective lens, it has the property of essentially solving the above problem. Since the region including the pattern to be processed has to be manipulated multiple times, there is a problem that the processing capacity is inevitably deteriorated.

[0010]

[The purpose of the device]

 The present invention has been made in order to eliminate the above-mentioned problems of the conventional ones, and provides a laser beam positioning device capable of accurately correcting a positional deviation of a laser beam without deteriorating the processing capacity. To aim.

[0011]

[Device configuration]

 The laser beam positioning device according to the present invention is a laser beam positioning device of a laser processing device that focuses a laser beam emitted from a light source onto a sample by an optical system and processes the sample. Adjusting means for adjusting the light intensity of the laser beam, and the laser beam whose light intensity is weakened by the adjusting means is focused on the sample by the optical system, the reflected light from the sample is imaged. Image data collecting means for collecting data, and calculation for calculating the amount of deviation between the irradiation position of the laser beam on the sample and the preset processing position from the image data collected by the image data collecting means Means for controlling the converging position of the laser beam by the optical system based on the shift amount calculated by the calculating means. Characterized in that a means.

[0012]

【Example】

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, a laser beam 100 emitted from a laser oscillator 1 passes through an optical attenuator 2 and a reflecting mirror 3 and enters a scanning mechanism 4. The laser beam 100 further passes through the objective lens 5 and is focused on the sample 6. Further, the laser beam 100 is scanned on the sample 6 in the x-axis and y-axis directions by driving the scanning mechanism 4 by the driving device 7.

The laser beam 100 irradiated on the sample 6 is reflected on the sample 6 and is incident on the TV camera 9 through the reflecting mirror 8 together with the irradiation point of the laser beam and the pattern in the vicinity thereof. The TV camera 9 converts the pattern of the laser beam irradiation point and its vicinity into an image signal, and sends the image signal to the image processing apparatus 10. The image processing device 10 processes the image signal from the TV camera 9 and also transmits the image signal to the television 11. Therefore, the operator can see the irradiation point of the laser beam and the pattern in the vicinity thereof through the television 11. The optical attenuator 2, the driving device 7, and the image processing device 10 are controlled by the controller 12, respectively.

2 and 3 are diagrams showing examples of images on the television 11 of FIG. FIG. 2 shows a case where the intersection of the crosshair 21 in the television 11 and the irradiation position 20 of the laser beam 100 coincide with each other, and FIG. 3 shows the intersection of the crosshair 21 in the television 11 and the irradiation of the laser beam 100. The case where the position 20 does not match is shown.

In a normal state, as shown in FIG. 2, the intersection of the cross hairs 21 and the irradiation position 20 of the laser beam 100 coincide with each other, so the controller 12 controls the drive unit 7 to drive it. The scanning mechanism 4 driven by moves the laser beam 100 to the position of the pattern 22 to be processed and processes the pattern to be processed.

On the other hand, as shown in FIG. 3, when the irradiation position 20 of the laser beam 100 is deviated from the intersection of the cross hairs 21, when the positioning is performed in the same manner as in the normal state, the pattern 22 to be processed is moved. It is not possible to process the regular part.

Therefore, first, the light intensity of the laser beam 100 is weakened and irradiated so that the sample 6 is not processed by the optical attenuator 2. At this time, if the laser oscillator 1 is an Nd: YAG laser that is generally used for processing, the wavelength is 1.06 μm. Therefore, if the TV camera 9 is a business or CCD, the reflected light of the laser beam 100 from the sample 6 is It can be detected.

Therefore, if the image signal from the TV camera 9 is processed by the image processing apparatus 10 by pattern recognition, it is possible to obtain the deviation from the intersection of the cross lines 21 of the irradiation position 20 of the laser beam 100. .. If the controller 12 controls the drive device 7 so as to correct the amount of deviation obtained from the image processing device 10, even if the irradiation position 20 of the laser beam 100 is deviated, the regular part of the processed pattern 22 is processed. You can

In this case, when the amount of displacement is large and passes through the peripheral portion of the objective lens 5, the shape of the laser beam 100 is distorted by the aberration of the object lens 5. Since it is not preferable to perform machining in such a state, if the controller 12 outputs an alarm depending on the amount of deviation, it is possible to manage the machining yield.

FIG. 4 is a block diagram showing another embodiment of the present invention. In the figure, in another embodiment of the present invention, the reflected light from the sample 6 is branched by the dichroic mirror 13, and the branched light is reflected by the infrared detection plate 15 and branched by the dichroic mirror 13. The configuration is the same as that of one embodiment of the present invention except that and are combined by using the half mirrors 14 and 17 and the reflecting mirror 16 and are incident on the TV camera 9. Is attached. Also, the operation of those same components is the same as that of the embodiment of the present invention.

Another embodiment of the present invention is an example in which a CO ₂ laser is used for the laser oscillator 1. That is, since the wavelength of the CO ₂ laser is 10.6 μm, the reflected light of the laser beam 100 from the sample 6 cannot be detected when the TV camera 9 is a vidicon or CCD.

Therefore, in the observation optical system, the reflected light of the laser beam 100 from the sample 6 is branched by the dichroic mirror 13, and the branched light is infrared light sensitive to the light having a wavelength of 10.6 μm. It is reflected by the detection plate 15. By combining the light reflected by the infrared detection plate 15 and the light branched by the dichroic mirror 13 using the half mirrors 14 and 17 and the reflecting mirror 16, the reflected light of the laser beam 100 from the sample 6 is combined. It can be detected by the TV camera 9.

As described above, the sample 6 is irradiated with the laser beam 100 that is sufficiently weakened by the optical attenuator 2, and the reflected light of the laser beam 100 from the sample 6 is converted into an image signal by the TV camera 9 and the image processing apparatus 10 is operated. The true irradiation position of the laser beam 100 can be obtained by performing the image processing with, and the correct position can always be processed.

This effect can be obtained by edge sensing using a laser beam for processing, but in edge sensing, it is necessary to scan about 10 times in order to obtain sufficient accuracy. For example, if a distance of 200 μm is scanned with an acceleration of 0.1 G, one scan requires 0.3 s, which results in a processing time of 3 s or more. On the other hand, in the present invention, only one image processing is required, and the typical processing time of commercially available image processing devices is 0.1 to 0.3 s, so the processing time should be increased by one digit or more. You can Therefore, the displacement of the laser beam can be accurately corrected without deteriorating the processing capacity.

[0026]

[Effect of the device]

 As described above, according to the present invention, when a laser beam whose light intensity is weakened is focused on a sample, the reflected light from the sample is collected as image data, and the laser beam calculated from this image data is collected. The laser beam focusing position is controlled by the optical system based on the amount of deviation between the irradiation position on the sample and the preset processing position, so that the laser beam There is an effect that the positional deviation can be accurately corrected.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an image on the television of FIG.

3 is a diagram showing an example of an image on the television of FIG.

FIG. 4 is a block diagram showing another embodiment of the present invention.

[Explanation of symbols]

 1 Laser Oscillator 2 Optical Attenuator 4 Scanning Mechanism 5 Objective Lens 6 Sample 7 Driving Device 9 TV Camera 10 Image Processing Device 12 Controller

Claims (1)

[Scope of utility model registration request] 1. A laser beam positioning device of a laser processing apparatus for processing a laser beam emitted from a light source onto a sample by an optical system and processing the sample, wherein the laser beam emitted from the light source is Adjusting means for adjusting the light intensity, and when the laser beam whose light intensity is weakened by the adjusting means is focused on the sample by the optical system, the reflected light from the sample is collected as image data. Image data collecting means, calculating means for calculating a deviation amount between the irradiation position of the laser beam on the sample and a preset processing position from the image data collected by the image data collecting means, and the calculating means. Control means for controlling the converging position of the laser beam by the optical system on the basis of the shift amount calculated in step 1. Laser beam positioning device.