JP2001018086A - Method and device for laser beam machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability and productivity of film forming. SOLUTION: A laser beam machining device 1 forms a film on an object A to be machined by irradiating the object to be worked with laser beams (a), (b) emitted from laser beam oscillators 2a, 2b and transmitting an aperture 9 and by supplying a raw material gas for film forming. The device 1 is provided with an image pickup device 5 to pick up the image of a face to be machined of the object to be machined as well as the region including a beam irradiation position and a controller to control a beam transmitting position and beam intensity for the aperture of the laser beam (b) on the basis of the photograph signal from the photograph device 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus and method suitable for use in correcting, for example, a defect in a photomask pattern.

[0002]

2. Description of the Related Art Generally, for example, an integrated circuit device (LSI)
When forming a wiring pattern of a liquid crystal display element (LCD), a photomask is used in an exposure process.

[0003] Such a pattern of a photomask is formed through a lithography process by forming a chromium film on a glass substrate, applying a resist, drawing by an electron beam, developing, etching, and removing the resist. . Defects may occur on the photomask formed through the lithography process due to a defect in the manufacturing process such as adhesion of dust or the like. There are two types of such defects. A defect in which an unnecessary pattern remains is called a residual defect (black defect), and a defect that is not formed in a portion where a desired pattern should be located is called a defect defect (white defect).

[0004] By the way, FIG.
In the case where a defect shown in FIG. 1 occurs, one of the repair methods is laser CVD (Chemical Vapor).
This is performed by forming a film of chromium (Cr) and its oxide as a film formation material on a glass substrate by using a deposition method. That is, a metal organic compound such as Cr is vaporized and supplied as a raw material gas onto an object to be processed (glass substrate), and a pattern is formed by thermally or photolytically decomposing the raw material gas. In the figure, reference numerals 31 and 32 denote a mask pattern and a defective portion, respectively.

Conventionally, in order to correct this kind of defective defect portion, a laser beam emitted from a laser oscillator and transmitted through an aperture is irradiated on an object to be processed, and a raw material gas for film formation is supplied. 2. Description of the Related Art A laser processing apparatus for forming a film on a processing target is employed.

[0006]

However, the conventional laser processing apparatus does not have a function of controlling the intensity distribution in the laser beam irradiated on the object to be processed. As shown in FIG. 4A, when the laser beam R is irradiated not only on the defective defect portion 32 (glass substrate) but also on a portion (existing film) 31 that does not require defect defect correction, the laser beam absorption amount of the existing film 31 is increased. Since the absorption amount of the laser beam by the glass substrate is smaller than that of the glass substrate, the film formation progress speed of the defect defect portion 32 is slower than the film formation progress speed of the existing film 31 as shown in FIG. . Further, in this type of laser processing apparatus, even when a pattern is newly formed on a glass substrate, unevenness of beam light irradiation intensity or the like occurs, and the film formation progress speed may vary depending on the beam light irradiation position.

Further, in the conventional laser processing apparatus, when the existing film 31 excessively absorbs the condensed spot of the laser beam, the deformation amount (tensile / compressive force) acting on the object to be processed due to the difference in thermal expansion of each material. Thermal stress corresponding to the strain was generated in the existing film 31.

As a result, there has been a problem that a uniform film thickness cannot be obtained at the time of film formation, or the existing film 31 is peeled off from the glass substrate, thereby lowering the reliability of film formation.

Therefore, in order to obtain a uniform film thickness, it is conceivable to irradiate the laser beam light again to a portion where the film formation progressing speed is slow to form a film. In this case, a long processing time (laser light irradiation time) is required. ), And there is a problem that productivity is reduced.

[0010] Japanese Patent Application Laid-Open Nos. Sho 61-268021 and Japanese Patent Publication No. Hei 3-79861 disclose "Photo CVD".
Prior arts are disclosed as "a method of manufacturing a thin film by using the method" and "a composite beam annealing method", but the above-mentioned problem has not been solved.

The present invention has been made in view of such circumstances, and in forming a film, an image of an area including a beam irradiation position, which is a processing target surface of a processing target, is formed based on the image pickup signal. It is an object of the present invention to provide a laser processing apparatus and method capable of improving reliability and productivity in film formation by controlling a beam transmission position and a beam intensity with respect to a beam aperture.

[0012]

In order to achieve the above object, a laser processing apparatus according to a first aspect of the present invention irradiates a laser beam emitted from a laser oscillator and transmitted through an aperture onto an object to be processed. A laser processing apparatus for forming a film on a processing object by supplying a source gas for film formation, an imaging apparatus for imaging an area including a beam irradiation position on a processing target surface of the processing object; The configuration includes a controller that controls a beam transmission position and a beam intensity with respect to an aperture of a laser beam based on an imaging signal from an imaging device. Therefore, at the time of film formation, a region including the beam irradiation position on the processing target surface of the processing target is imaged by the imaging device, and based on an imaging signal from the imaging device, the beam transmission position and the beam intensity with respect to the aperture of the laser beam are controlled by the controller. Is controlled by

According to a second aspect of the present invention, in the laser processing apparatus of the first aspect, the laser oscillator includes a plurality of laser oscillators that emit laser beams independently of each other. Therefore, an area including the beam irradiation position on the processing target surface of the processing target at the time of film formation is imaged by the imaging device, and the beam transmission of the laser beam emitted from each laser oscillator to the aperture based on the imaging signal from the imaging device is performed. The position and beam intensity are controlled by a controller.

According to a third aspect of the present invention, in the laser processing apparatus of the second aspect, a driving mirror that reflects at least one laser beam among the laser beams, and a reflected beam from the driving mirror and another laser beam are used. The configuration has a beam combiner for combining. Therefore,
After at least one of the laser beams reflects off the drive mirror, the reflected beam and another laser beam are combined in a beam combiner.

According to a fourth aspect of the present invention, in the laser processing apparatus of the first aspect, a beam splitter for splitting a laser beam emitted from a laser oscillator into a plurality of laser beams is provided. Therefore, an area including the beam irradiation position, which is the processing target surface of the processing target at the time of film formation, is imaged by the imaging device, and the beam transmission position with respect to the aperture of the laser beam divided by the beam splitter based on the imaging signal from the imaging device. And beam intensity are controlled by a controller.

According to a fifth aspect of the present invention, in the laser processing apparatus according to any one of the first to fourth aspects, an X-Y capable of moving an object to be processed in two directions perpendicular to each other within a laser beam irradiation surface. It has a configuration having a table. Therefore, the object to be processed is transferred in two directions perpendicular to each other by the XY table during film formation.

The invention according to claim 6 (laser processing method)
In the laser processing method of irradiating a laser beam emitted from a laser oscillator and passing through an aperture onto a processing object and supplying a source gas for film formation, a film is formed on the processing object. In doing so, there is a method in which a region including a beam irradiation position on a processing target surface of a processing target is imaged, and a beam transmission position with respect to an aperture of a laser beam and a beam intensity are controlled based on the imaged signal. Therefore, film formation on the object to be processed is
This is performed by imaging a region including the beam irradiation position on the processing target surface of the processing target, and controlling the beam transmission position and the beam intensity with respect to the aperture of the laser beam based on the imaging signal.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a block diagram schematically showing a laser processing apparatus according to the first embodiment of the present invention.
In FIG. 1, a CVD laser processing apparatus denoted by reference numeral 1 includes a laser oscillator 2, a first optical system 3, a second optical system 4, an imaging device 5, and a controller 6. As a result, a laser beam a is irradiated onto a processing target A in a chamber (not shown), and a raw material gas G is supplied. When the raw material gas G is supplied, a thin film using the raw material gas (for example, chromium carbonyl gas) G as a film forming material is formed. Is formed.

The workpiece A is conveyed from the outside of the chamber into the chamber during film formation, and is positioned on an XY table (not shown). Thereby, the workpiece A
Are transported in the chamber in two directions perpendicular to each other according to the processing target position (film formation position).

The laser oscillator 2 is composed of two main and sub-laser oscillators 2a and 2b, each of which is parallel to each other, disposed behind the first optical system 3 and connected to the controller 6. Thus, when the laser beam a is emitted from the laser oscillator 2a, the laser beam a is irradiated onto the processing target A via the first optical system 3 and the second optical system 4 (both partially). On the other hand, when the laser beam b is emitted from the laser oscillator 2b, it is irradiated on the processing target A via the first optical system 3 and the second optical system 4 (partly).

The first optical system 3 has a drive mirror 7, a beam combiner 8, an aperture 9, and a relay lens 10,
It is arranged in front of the laser oscillator 2. This allows
When the laser beams a and b from the laser oscillators 2 a and 2 b pass through the first optical system 3, they enter the second optical system 4.

The drive mirror 7 is disposed rotatably in front of the laser oscillator 2b, and is connected to the controller 6 via an actuator 7a. Thus, when the drive mirror 7 (actuator 7a) receives the control signal from the controller 6, it rotates to a predetermined rotation position to convert the laser beam b from the laser oscillator 2b into a beam combiner 8
To reflect.

The beam combiner 8 is arranged in front of the laser oscillator 2a and is arranged in parallel with the drive mirror 7. As a result, when the laser beam a emitted from the laser oscillator 2a passes through the beam combiner 8 and the laser beam b emitted from the laser oscillator 2b is reflected by the drive mirror 7 and enters the beam combiner 8, both of these lasers Beams a and b are combined.

The aperture 9 is composed of an aperture whose aperture size is variable, and includes a beam combiner 8 and a relay lens 10.
It is arranged between and. Thereby, the laser oscillator 2
When the laser beam a from a passes through the aperture 9,
As shown in FIG. 2, the beam is irradiated onto the processing target A with a beam shape (rectangular shape) corresponding to the aperture size of the aperture 9. On the other hand, when the laser beam b from the laser oscillator 2b passes through the aperture 9, the processing object A has the beam shape (circular shape) of the laser beam itself as shown in FIG.
Irradiated on top.

The relay lens 10 is disposed near the second optical system 4. Thereby, both laser oscillators 2a,
When the laser beams a and b from 2 b pass through the relay lens 10, they enter the second optical system 4.

The second optical system 4 has an objective lens 11, a beam splitter 12, and an imaging lens 13, and is disposed above the workpiece A. As a result, the laser beams a and b from the first optical system 3 are
And the reflected light passes through the objective lens 11 to form an image on the processing target A.

The imaging device 5 comprises a CCD camera, is disposed above the second optical system 4, and is connected to the controller 6. Accordingly, an area including the beam irradiation position on the processing target surface of the processing target A is imaged via the second optical system 4. Then, this imaging signal is output to the controller 6 as image data.

The controller 6 has an image processing section (not shown) for performing image processing upon receiving an image signal from the image pickup device 5, and is connected to the laser oscillator 2, the image pickup device 5, the drive mirror 7 and the aperture 9. ing. Thereby, based on the processing result in the image processing unit in the controller 6, the driving mirror 7 is rotated to open the aperture 9 of the laser beam b.
And the beam intensity of the laser beam b is controlled.

Next, a laser processing method according to the first embodiment of the present invention will be described with reference to FIGS. That is, the pattern formation (film formation) on the glass substrate by the laser processing method in the present embodiment irradiates the processing target A with the laser beams a and b emitted from the laser oscillators 2a and 2b and transmitted through the aperture 9. This is performed by supplying a source gas for film formation. At this time, the imaging device 5 captures an image of an area including the beam irradiation position on the processing target surface of the processing target A. Further, the controller 6 performs image processing from an image signal of the imaging device 5, and controls a beam transmission position and a beam intensity of the laser beam b with respect to the aperture 9 based on the image processing result.

On the other hand, as shown in FIG. 2, when a defect defect occurs in the pattern, the laser beam b from the laser oscillator 2b has a beam intensity higher than the beam intensity of the laser beam a and the aperture 9 This is performed by transmitting light through a predetermined opening position in the aperture 9 with a beam shape (circular shape) smaller than the opening size described above, and irradiating the processing object A (glass substrate).

Therefore, in the present embodiment, at the time of film formation, a region including the beam irradiation position, which is a processing target surface of the processing target A, is imaged by the imaging device 5, and a laser beam is generated based on an imaging signal from the imaging device 5. Since the beam transmission position of the beam b with respect to the aperture 9 and the beam intensity of the laser beam b are controlled by the controller 6, the film formation progress speed at each beam irradiation position is set to the same film formation progress speed, and the defect defect is corrected. Thermal stress sometimes generated in the existing film is suppressed, and a uniform film thickness can be obtained at the time of film formation, and peeling of the existing film can be prevented.
Furthermore, in the present embodiment, the fact that a uniform film thickness is obtained at the time of film formation can reliably reduce the processing time.

In this embodiment, a plurality of laser beams a and b are provided by a plurality of laser oscillators 2a and 2b.
Although the case of emitting a laser beam has been described, the present invention is not limited to this, and a single laser oscillator can emit a plurality of laser beams. In this case, a beam splitter that splits a laser beam emitted from a laser oscillator into a plurality of laser beams is used.

Further, in the present embodiment, the laser beam b is scanned by the
Although the case of irradiating above has been described, the present invention is not limited to this, and the beam may be shaped and irradiated by an aperture separate from the aperture 9.

In addition, in the present invention, the wavelengths and oscillation modes (pulse oscillation and continuous oscillation) of the laser beams emitted from the plurality of laser oscillators may be the same or different.

[0035]

As described above, according to the present invention, at the time of film formation, a region including a beam irradiation position on a processing target surface of a processing target object is imaged by an image pickup device, and an image pickup signal from the image pickup device is generated. The controller controls the beam transmission position and beam intensity with respect to the aperture of the laser beam based on the controller, so the film formation progress speed at each beam irradiation position is set to the same film formation progress speed, and it occurs in the existing film when defect defects are corrected Heat stress is suppressed.

Accordingly, a uniform film thickness can be obtained at the time of film formation, and the occurrence of peeling of the existing film can be prevented, so that the reliability of the film formation can be improved.
In addition, since a uniform film thickness can be obtained at the time of film formation, the processing time can be reliably shortened, and therefore, productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a laser processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a plan view for explaining a laser processing method according to the first embodiment of the present invention.

FIG. 3 is a plan view showing a state in which a defective defect has occurred in a mask pattern.

FIGS. 4A and 4B are plan views illustrating a conventional laser processing example.

[Explanation of symbols]

 Reference Signs List 1 laser processing device 2, 2a, 2b laser oscillator 3 first optical system 4 second optical system 5 imaging device 6 controller 7 drive mirror 8 beam combiner 9 aperture A processing object G raw material gas a, b laser beam

Claims (6)

[Claims] 1. A laser processing apparatus for irradiating a laser beam emitted from a laser oscillator and passing through an aperture onto a processing target object and supplying a source gas for film formation to form a film on the processing target object. An imaging device that images a region including a beam irradiation position on a processing target surface of the processing target, based on an imaging signal from the imaging device, a beam transmission position of the laser beam with respect to the aperture and a beam intensity. A laser processing apparatus characterized by including a controller for controlling. 2. The laser processing apparatus according to claim 1, wherein said laser oscillator comprises a plurality of laser oscillators for emitting laser beams independently of each other. 3. A drive mirror for reflecting at least one of the laser beams, and a beam combiner for combining a reflected beam from the drive mirror with another laser beam. The laser processing apparatus according to the above. 4. The laser processing apparatus according to claim 1, further comprising a beam splitter for dividing a laser beam emitted from the laser oscillator into a plurality of laser beams. 5. The laser processing according to claim 1, further comprising an XY table that can transfer the object to be processed in two directions perpendicular to each other within a laser beam irradiation surface. apparatus. 6. A laser processing method for irradiating a processing object with a laser beam emitted from a laser oscillator and passing through an aperture, and supplying a source gas for film formation, thereby forming a film on the processing object. In forming a film, an image of a region including a beam irradiation position on a processing target surface of the processing target is captured, and a beam transmission position and a beam intensity of the laser beam with respect to the aperture are controlled based on the imaging signal. A laser processing method characterized by the above-mentioned.