JP2007229785A - Laser machining system and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for suppressing deterioration in a mask caused by oxidation in a laser machining system for performing the machining of a work by laser light passed through an opening part provided at the mask in a preset atmosphere. <P>SOLUTION: The laser machining system comprises: a first treatment chamber 13 for setting the circumference of a mask 24 into a first atmosphere; and a second treatment chamber 20 for setting the circumference of the work into a second atmosphere different from the first atmosphere. The laser machining system further comprises: first gas introduction means 16, 17 for introducing gas into the first treatment chamber; second gas introduction means 16, 17 for introducing gas into the second treatment chamber; and a gas control means 18 for performing the control of the gas introduction by the first gas introduction means and the second gas introduction means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a control method, and more particularly to a laser processing apparatus and a control method for realizing a high operating rate.

Conventionally, a processing target such as a semiconductor is processed using a CO ₂ (carbon dioxide) laser, a YAG laser, an excimer laser, or the like. In addition, the laser beam is focused on the processing surface of the object to be processed, and the beam spot diameter is narrowed by passing through an opening (slit) provided in the mask, and welding and cutting utilizing high energy density. It is used for processing such as drilling.

  As another method, annealing (surface modification) that improves the surface function of the material by setting the beam spot diameter to a certain extent (1 to several mm) with a mask and melting only a limited area of the processing surface ) Is also used as a process (for example, see Patent Document 1).

  Note that in the case where the above-described annealing treatment is performed, the processing is performed using a processing chamber such as a chamber in order to process an object to be processed in an atmosphere different from the outside air (air atmosphere). That is, various surface modification reactions can be caused by introducing an inert gas into the processing chamber, reducing the pressure, raising the temperature, applying light, electricity, magnetism, or the like.

For example, when annealing a relatively large substrate such as a liquid crystal substrate, a processing chamber for maintaining an annealing atmosphere such as nitrogen is provided, and the substrate such as an XY stage is moved into the processing chamber. Annealing treatment is performed by moving the object to be processed in various directions in the chamber while irradiating laser light with a laser processing apparatus provided with a mechanism.
JP 2001-44136 A

  By the way, as shown in Patent Document 1, usually, a chamber for providing a predetermined atmosphere around the workpiece is provided, and the mask is installed in the outside air. However, particularly in the case of performing the annealing treatment described above, since the laser light is continuously irradiated for a long time, the mask absorbs the laser energy and the temperature rises, thereby causing deterioration due to oxidation of the mask. Therefore, every time deterioration due to oxidation, it is necessary to change the mask and further adjust the opening to an accurate position. Therefore, since the laser processing cannot be performed when the mask is changed, the operating rate of the laser processing apparatus is lowered.

  In addition, as a technique for suppressing the oxidation of the mask, a technique is also conceivable in which a mask is placed in a processing object chamber shown in Patent Document 1 and an atmosphere for suppressing the oxidation is set. Since it is provided to adjust the atmosphere suitable for processing an object, it is different from the atmosphere suitable for suppressing oxidation of the mask. Further, if the mask is included in the chamber, the space (volume) of the chamber is increased, the amount of inert gas introduced is increased, and it takes time to make the atmosphere in the chamber a predetermined atmosphere. It does not improve the operating rate.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a laser processing apparatus and a control method for realizing a high operating rate.

  In order to achieve the above-mentioned object, the present invention provides a laser processing apparatus for processing a workpiece by laser light that has passed through an opening provided in a mask in a preset atmosphere. A first processing chamber for forming a first atmosphere, and a second processing chamber for forming a second atmosphere around the workpiece to be different from the first atmosphere. To do. Thereby, it can suppress that degradation arises by oxidizing a mask. Therefore, it is possible to realize a high operating rate of the laser processing apparatus.

  Furthermore, a first gas introducing means for introducing gas into the first processing chamber, a second gas introducing means for introducing gas into the second processing chamber, the first gas introducing means, and the first gas introducing means. It is preferable to have gas control means for controlling the gas introduction of the second gas introduction means. Thereby, suppression of the oxidation of the mask and laser processing in an optimum atmosphere can be realized.

  Furthermore, it is preferable that the gas control unit controls the first gas introduction unit so that the first processing chamber has an atmosphere having a high inert gas concentration. Thereby, deterioration due to oxidation of the mask can be suppressed.

  Further, the first processing chamber has a transmission window on at least one surface for allowing laser light to enter the first processing chamber and to pass through the opening and to exit the first processing chamber. It is preferable to have. Thereby, the attenuation | damping by transmission can be suppressed by allowing a laser beam to pass through a transmission window.

  According to another aspect of the present invention, there is provided an atmosphere control method in a laser processing apparatus for processing an object to be processed by laser light that has passed through an opening provided in a mask in a preset atmosphere. A first gas introduction step for bringing the atmosphere into one atmosphere, and a second gas introduction step for bringing the periphery of the workpiece into a second atmosphere, and further including the first gas introduction step and the second gas introduction step. And a gas control step for performing gas introduction control in the gas introduction step. Thereby, deterioration due to oxidation of the mask can be suppressed. Therefore, it is possible to realize a high operating rate of the laser processing apparatus.

  Furthermore, it is preferable that the gas control step means controls the introduction of gas so that the first atmosphere becomes an atmosphere having a high inert gas concentration. Thereby, deterioration due to oxidation of the mask can be suppressed.

  According to the present invention, it is possible to suppress deterioration due to oxidation of the mask. Thereby, the high operating rate of the laser processing apparatus can be realized.

  Hereinafter, preferred embodiments of a laser processing apparatus and a control method according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of a schematic configuration of a laser processing apparatus according to the present invention. A laser processing apparatus 10 shown in FIG. 1 includes a laser oscillator 11, a reflection mirror 12, a first chamber (first processing chamber) 13, a mask stage 14, a mask stage driving unit 15, and a gas introduction unit 16. The gas discharge unit 17, the gas control unit 18, the imaging lens 19, the second chamber (second processing chamber) 20, the processing stage 21, the processing stage driving unit 22, and the control unit 23. It is configured.

The laser oscillator 11 emits pulsed laser light at a predetermined timing according to a control signal obtained from the control means 23. Here, in this embodiment, as the laser light, for example, an XeCl excimer laser having 1 pulse energy of 1 J, an oscillation frequency of 300 Hz, and a wavelength of 308 nm can be used. The type of laser light in the present invention is not particularly limited, and for example, a KrF excimer laser with a wavelength of 248 nm, a KrCl excimer laser with a wavelength of 222 nm, a YAG laser, a CO ₂ laser, or the like can be used.

  The reflection mirror 12 reflects the laser light emitted from the laser oscillator 11 to the first chamber 13 side.

  The first chamber 13 is adjusted so that the atmosphere around the mask 24 has an inert gas having a predetermined concentration, or the mask has a predetermined pressure. Further, the first chamber 13 allows laser light to enter the chamber, pass through an opening (slit) having a predetermined shape formed in the mask 24, and emit light outside the first chamber 13. A transmission window made of a transparent material such as quartz glass is provided on at least one surface of the first chamber 13. Thereby, attenuation during transmission of laser light can be suppressed. Details of the installation position of the transmission window will be described later.

  The mask stage 14 is a stage for moving the mask 24 to a predetermined position. For example, the mask 24 is fixed on the mask stage 14 by vacuum suction or the like. As the mask 24, for example, a chrome mask that can be manufactured inexpensively and can be manufactured in a short time can be used. The mask 24 has an opening (slit) for making the laser beam into a predetermined shape.

  Here, the mask stage 14 has an opening at a position where the laser beam passes so that the laser beam that has passed through the slit of the mask 24 does not come into contact with the laser beam when passing through the mask stage. Details of the mask stage 14 will be described later.

  Further, the mask stage driving means 15 moves the mask stage 14 in the vertical direction (X, Y direction) or the optical axis direction (Z direction) with respect to the optical axis of the laser beam shown in FIG. And the mask 24 is moved to a predetermined position by moving it in a predetermined inclination angle θ direction with respect to the optical axis.

  Further, the mask stage driving means 15 performs driving such as taking the mask 24 out of the first chamber 13 together with the mask stage 14 when the mask 24 is replaced. When positioning the mask 24 when the mask 24 is replaced, etc., a plurality of alignment marks provided on the mask 24 are confirmed by a CCD camera (not shown) provided on the laser processing apparatus 10 or the like. The mask 24 can be positioned at an accurate position.

  Further, the gas introduction means (first gas introduction means) 16-1 is inactivated by a control signal obtained from the gas control means 18 so that the inside of the first chamber 13 has an atmosphere of a predetermined inert gas concentration. Introduce gas. The inert gas is preferably inexpensive nitrogen gas, but is not particularly limited in the present invention. For example, other inert gases such as argon gas and helium gas can be used.

  The gas discharge means 17-1 discharges the gas in the first chamber 13 by a control signal obtained from the gas control means 18 when the inside of the first chamber 13 is evacuated.

  That is, the laser beam irradiated in the first chamber 13 passes through a slit provided in the mask 24 to become a laser beam having a predetermined shape and is irradiated from the first chamber 13 to the imaging lens 19. The imaging lens 19 is an imaging lens that focuses the laser light in order to form an image with a predetermined intensity of the laser light applied to the workpiece (workpiece) 25. The laser light that has passed through the imaging lens 19 is irradiated to the second chamber 20.

  The second chamber 20 is adjusted so that the atmosphere around the workpiece 25 has an inert gas having a predetermined concentration, or the mask has a predetermined pressure. The second chamber 20 is provided with a transmission window made of a transparent material such as quartz glass on at least one surface in order to allow laser light to enter the chamber.

  The processing stage 21 is a stage for moving the processing object 25 to a predetermined position. For example, the mask 24 is fixed on the mask stage 14 by vacuum suction or the like. The processing object 25 used in the present embodiment includes, for example, a resin substrate, glass, ceramic or Si semiconductor material, metal, plastic, etc., but is not particularly limited in the present invention. In addition, a transmission window made of a transparent material such as quartz glass is provided on the light incident surface of the laser beam in the second chamber 20.

  The processing stage drive unit 22 is configured to control the processing stage 21 in a direction perpendicular to the optical axis of the laser beam shown in FIG. And the workpiece 25 is moved to a predetermined position by moving it in the direction of a predetermined inclination angle θ with respect to the optical axis. Further, during the laser irradiation, laser processing such as annealing can be performed on the surface of the workpiece 25 by moving the laser beam in a predetermined direction at a predetermined speed.

  Further, the processing stage driving means 22 drives the processing target 25 to be moved out of the second chamber 20 together with the processing stage 21 when the processing target 25 is replaced. When positioning the processing object 25 when the processing object 25 is replaced, a plurality of alignment marks provided on the processing stage 21 are provided with a CCD camera (not shown) provided on the laser processing apparatus 10 or the like. By confirming according to the above, it is possible to position the processing object 25 at an accurate position.

  Further, the gas introduction means (second gas introduction means) 16-2 is inactivated by a control signal obtained from the gas control means 18 so that the inside of the second chamber 20 has an atmosphere of a predetermined inert gas concentration. Introduce gas. The inert gas is preferably inexpensive nitrogen gas, but is not particularly limited in the present invention. For example, other inert gases such as argon gas and helium gas can be used.

  Further, the gas discharge means 17-2 discharges the gas in the second chamber 20 by a control signal obtained from the gas control means 18 when the inside of the second chamber 20 is evacuated.

  Note that the gas control means 18 can adjust the inert gas in the first chamber 13 and the second chamber 20 as described above. Specifically, the gas control means 18 measures the concentration of the inert gas in the atmosphere (first atmosphere) in the first chamber 13 and the atmosphere (second atmosphere) in the second chamber 20 (see FIG. (Not shown) or the like, and control is performed so that a predetermined atmosphere is obtained.

  At this time, the inert gas concentration in the first chamber 13 is set so that the inert gas has a high concentration so that the oxidation rate of the mask is as slow as possible (or not oxidized). For example, when nitrogen gas is used, it is set so that about 99.99% of the total atmosphere becomes nitrogen gas. On the other hand, the inert gas concentration in the second chamber 20 is set to be an inert gas concentration suitable for processing such as annealing of the workpiece 25. For example, when nitrogen gas is used, it is set so that about 85 to 99% of the total atmosphere becomes nitrogen gas.

  Thereby, deterioration due to oxidation of the mask can be suppressed. Therefore, the number of mask replacements is reduced, and high efficiency of the laser processing apparatus can be realized. In addition, by controlling the inside of each chamber to an optimum atmosphere, high-precision laser processing can be realized.

  The control means 23 also oscillates the laser light from the laser oscillator 11, drives the mask stage 14 by the mask stage driving means 15, drives the processing stage 21 by the processing stage driving means 22, and gas in the gas control means 18. Control introduction and discharge timing.

<First chamber 13>
Here, an installation example of the transmission window in the first chamber 13 in the embodiment shown in FIG. 1 will be described with reference to the drawings. FIG. 2 is a diagram illustrating an example of installation of a transmission window in the first chamber.

  As shown in FIG. 2A, the first chamber 13 crosses the optical axis of the laser light through transmission windows 31 and 32 for allowing the laser light to pass through the first chamber 13 through a mask. It is provided on the opposite side of the chamber 13. As a result, the laser light that has passed through the transmission window 31 and entered the first chamber 13 can be emitted from the transmission window 32 to the outside of the first chamber 13 through the mask 24 in a predetermined shape.

  In addition, as shown in FIG. 2B, the configuration of the first chamber 13 can be further simplified and made inexpensive by adopting a configuration having only one transmission window 33. In this case, reflecting mirrors 41-1 and 41-2 are provided in the chamber in order to input and output laser light through one transmission window. As a result, the laser light that has entered the first chamber 13 through the transmission window 33 passes through the mask 24 and the reflection mirrors 41-1 and 41-2 in a predetermined shape from the transmission window 33 to the first chamber 13. It can be emitted outside.

  As the transmission windows 31, 32, 33, for example, quartz glass can be used. By using quartz glass, attenuation during transmission of laser light can be reduced. In the present invention, the material of the passing window is not limited to this. Furthermore, parts other than the transmission window of the first chamber 13 are formed of, for example, stainless steel.

<Mask stage 14>
Next, the mask stage 14 will be described. The mask stage 14 passes through a slit having a predetermined shape formed in the mask 24 to prevent attenuation of the laser light having a predetermined shape, so that an opening (mask stage) having a predetermined size is formed at a predetermined position. Opening).

  Here, FIG. 3 is a diagram for explaining the positional relationship between the mask stage and the mask. In FIG. 3, the mask stage 14 and the mask 24 are separated from each other, but the mask 24 is fixed on the mask stage 14 by vacuum suction or the like as described above during use.

  As shown in FIG. 3, the mask 24 has a slit 51 for making the laser beam have a predetermined shape. The mask stage 14 has a mask stage opening 52 having an area larger than the opening area of the slit 51 so that laser light having a predetermined shape that has passed through the mask 24 does not come into contact. The mask stage opening 52 shown in FIG. 3 is formed in a rectangular shape, but is not limited to this in the present invention, and may be, for example, a circle or a polygon. As a result, the laser beam that has passed through the mask shape of the mask 24 can pass without contacting the mask stage 14. Therefore, useless attenuation of the laser beam can be prevented.

  As described above, according to the present invention, deterioration due to oxidation of the mask can be suppressed. Therefore, it is possible to realize a high operating rate of the laser processing apparatus.

  The laser processing in the present invention is not limited to the annealing process, and can be applied to processes other than annealing such as drilling and grooving.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be changed.

It is a figure which shows an example of schematic structure of the laser processing apparatus in this invention. It is a figure of an example for demonstrating the installation example of the permeation | transmission window in a 1st chamber. It is a figure for demonstrating the positional relationship of a mask stage and a mask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laser processing apparatus 11 Laser oscillator 12, 41 Reflection mirror 13 1st chamber (1st processing chamber)
DESCRIPTION OF SYMBOLS 14 Mask stage 15 Mask stage drive means 16 Gas introduction means 17 Gas discharge means 18 Gas control means 19 Imaging lens 20 Second chamber (second processing chamber)
DESCRIPTION OF SYMBOLS 21 Processing stage 22 Processing stage drive means 23 Control means 24 Mask 25 Processing target object 31,32,33 Transmission window 51 Slit 52 Mask stage opening part

Claims (6)

In a laser processing apparatus for processing an object to be processed by laser light that has passed through an opening provided in a mask in a preset atmosphere,
A first processing chamber for providing a first atmosphere around the mask;
A laser processing apparatus, comprising: a second processing chamber for making a periphery of the processing object a second atmosphere different from the first atmosphere. First gas introduction means for introducing gas into the first processing chamber;
Second gas introduction means for introducing gas into the second processing chamber;
The laser processing apparatus according to claim 1, further comprising a gas control unit that controls gas introduction of the first gas introduction unit and the second gas introduction unit. The gas control means includes
3. The laser processing apparatus according to claim 1, wherein the first gas introduction unit is controlled so that the atmosphere in the inert gas concentration is high in the first processing chamber. 4. The first processing chamber is
2. A transmission window for allowing a laser beam to enter the first processing chamber, pass through the opening, and exit the first processing chamber, on at least one surface. 4. The laser processing apparatus according to any one of 3 above. In a method for controlling an atmosphere in a laser processing apparatus that processes an object to be processed by laser light that has passed through an opening provided in a mask in a preset atmosphere,
A first gas introduction step for setting a first atmosphere around the mask;
A second gas introduction step for setting the periphery of the workpiece to a second atmosphere,
And a gas control step for performing gas introduction control in the first gas introduction step and the second gas introduction step. The gas control step means includes
The control method according to claim 5, wherein the introduction of the gas is controlled so that the first atmosphere is an atmosphere having a high inert gas concentration.

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