JP2009010161A - Laser machining device and laser machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser machining device capable of performing machining of high quality. <P>SOLUTION: The laser machining device includes: a holding mechanism which holds an object to be machined having a defined surface to be machined movably along the surface to be machined; a laser optical system which makes a laser beam LB incident on a partial region on the surface to be machined of the object to be machined which is held by the holding mechanism; a moving mechanism which moves the object to be machined which is held by the holding mechanism along the surface to be machined; and a height adjusting mechanism 42 which supports the region, where the laser beam from the laser optical system is incident, of the object to be machined which is held by the holding mechanism and displaces the supported region along the height with respect to the surface to be machined. The height adjusting mechanism supports part of the object to be machined so that the object to be machined can move relatively to the height adjusting mechanism in a direction along the surface to be machined. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus that performs processing by irradiating a workpiece with a laser beam, and a laser processing method.

  In one manufacturing process of a liquid crystal panel, an amorphous silicon film formed on a glass substrate is irradiated with a laser beam to crystallize the amorphous silicon film (laser annealing).

  In this laser annealing, the entire surface of the glass substrate is adsorbed to the suction disk, the height of the glass substrate is detected by a height detector, and the glass substrate is placed so that the amorphous silicon film is positioned within the focal depth of the laser beam. Raise and lower with the suction board.

  However, this method requires high flatness of the suction disk. In addition, since the height is adjusted by moving both the glass substrate and the suction disk, the weight of the moving part increases and the controllability is poor. Furthermore, it has been difficult to cope with the waviness and thickness variations of the glass substrate itself.

  Without using a suction board, “By providing a mechanism to blow out air to the work receiver that is the board installation part, a gap is formed between the substrate and the work receiver, and the air flow rate is controlled by the sensor so that the gap is kept at a constant distance. An invention of a “laser processing apparatus provided with a control mechanism” is disclosed (for example, see Patent Document 1).

  The laser processing apparatus described in Patent Document 1 is configured to include a stage including a workpiece receiver on which a substrate is placed. The workpiece receiver includes an air outlet for forming a gap with the substrate, and a gap sensor that is provided corresponding to each air outlet and measures the distance between the substrate and the workpiece receiver.

  By supplying air to the air outlet, a gap is formed between the substrate and the workpiece receiver. The formed gap is measured by a gap sensor, and based on the measurement result, the flow rate of air flowing out from the air outlet is adjusted so that the laser processing focal position becomes constant at a predetermined position, and the gap is adjusted. The adjustment of the air flow rate and the adjustment of the gap are performed by providing a flow rate adjustment mechanism and independently controlling the air valves that supply air to the respective air outlets.

  In the laser processing apparatus described in Patent Document 1, for example, an air outlet that is a mechanism for adjusting a gap between the substrate and the workpiece receiver is disposed at a position corresponding to the entire surface of the substrate.

JP 2001-252784 A

  The objective of this invention is providing the laser processing apparatus which can implement | achieve high quality processing.

  Moreover, it is providing the laser processing apparatus which can be reduced in size.

  Furthermore, it is providing the laser processing method which can implement | achieve high quality processing.

  According to one aspect of the present invention, a workpiece to be processed in which a workpiece surface is defined is held so as to be movable in a direction along the workpiece surface, and a workpiece to be processed held by the holding mechanism is covered. A laser optical system for injecting a laser beam into a partial region of the processing surface, a moving mechanism for moving the processing object held by the holding mechanism in a direction along the processing surface, and the holding mechanism A height adjusting mechanism that supports a region of the workpiece to which the laser beam from the laser optical system is incident and displaces the supported region in a height direction with respect to the processing surface; The height adjusting mechanism is provided with a laser processing apparatus that supports a part of the processing object such that the processing object can move relative to the height adjusting mechanism in a direction along the surface to be processed.

  According to another aspect of the present invention, (a) a surface to be processed is defined, and a portion in the path of the laser beam is moved with respect to the surface to be processed by bending a flexible workpiece. There is provided a laser processing method including a step of displacing in the height direction, and (b) a step of causing a laser beam to enter the displaced portion after displacing the portion in the path of the laser beam.

  ADVANTAGE OF THE INVENTION According to this invention, the laser processing apparatus which implement | achieves a high quality process can be provided.

  In addition, a miniaturized laser processing apparatus can be provided.

  Furthermore, a laser processing method that realizes high-quality processing can be provided.

  FIG. 1 is a schematic diagram illustrating a laser processing apparatus according to an embodiment.

  A laser beam LB is emitted from the laser light source 30. The laser beam LB is reflected by the folding mirrors 31 a and 31 b and enters the homogenizer 32. The homogenizer 32 includes a focus lens 32a.

  The homogenizer 32 shapes the beam cross section of the laser beam LB into a long shape on the homogenization surface, and uniformizes the light intensity distribution in the long direction within the beam cross section.

  A flexible substrate 50 is held above the substrate floating pad 40. The substrate 50 has a glass substrate and an amorphous silicon film formed thereon. The substrate 50 is held, for example, at a position where the surface (amorphous silicon film surface) is equal to the height of the homogenized surface of the homogenizer 32. The amorphous silicon film is irradiated with a long laser beam LB having a uniform light intensity distribution, and the amorphous silicon film is crystallized (laser annealing).

  FIG. 2 is a schematic view showing the vicinity of the substrate floating pad. For convenience of explanation, an XZ orthogonal coordinate system is defined in which the right direction in the figure is the X-axis direction and the upward direction is the Z-axis direction.

  The substrate floating pads 40a to 40c blow out air 60 from the upper surface thereof, and cause the substrate 50 to air float (air bearing). For example, the air 60 is blown out so that the gap amount between the substrate floating pads 40a to 40c and the substrate 50 is constant. The substrate 50 is held so that the perpendicular direction (height direction) and the Z-axis direction are parallel to each other. Since the substrate 50 and the upper surfaces of the substrate floating pads 40a to 40c are not in contact with each other, the substrate 50 is prevented from being damaged.

  The laser beam LB emitted from the homogenizer is incident on the surface of the substrate 50 held above the substrate floating pad 40b. The optical axis direction of the laser beam LB is, for example, parallel to the Z-axis direction.

  The height detector 41 is disposed in the vicinity of the substrate floating pad 40b, and detects the position (height) along the Z-axis direction of the surface of the substrate 50 in the region where the laser beam LB is incident above the substrate floating pad 40b.

  A height control mechanism 42 is provided on the substrate floating pad 40b. Along with the substrate floating pad 40b, the height control mechanism 42 is a part of the substrate 50 (substrate floating) so that the substrate 50 can move relative to the height control mechanism 42 and the substrate floating pad 40b in the direction along the surface of the substrate 50. The upper portion of the pad 40b is supported.

  The height control mechanism 42 moves the substrate floating pad 40b along the Z-axis direction based on the height of the surface of the substrate 50 detected by the height detector 41. By the movement of the substrate floating pad 40b, the substrate 50 at the position where the laser beam LB is incident moves along the Z-axis direction. The height control mechanism 42 moves the substrate 50 up and down via the substrate floating pad 40b so that the height of the substrate 50 at the position where the laser beam LB enters coincides with the height of the homogenization surface of the homogenizer.

  When the laser processing apparatus according to the embodiment is used, the incident height of the laser beam LB on the substrate 50 can be made to coincide with the height of the homogenized surface regardless of the undulation or thickness variation of the substrate 50. Processing can be realized. Further, since only a part of the substrate 50 is moved up and down, the alignment of the surface of the substrate 50 and the homogenized surface can be performed at high speed and with high accuracy. Furthermore, since the rigidity of the substrate 50 only needs to be maintained at the irradiation position of the laser beam LB, the laser processing apparatus can be reduced in size.

  FIG. 3 is a schematic plan view of the laser processing apparatus viewed from a direction parallel to the optical axis of the laser beam LB (Z-axis direction). The Y-axis direction perpendicular to the X-axis direction and the Z-axis direction shown in FIG. 2 is defined upward in the figure.

  Although only the substrate floating pads 40a to 40c are shown in FIG. 2, the laser processing apparatus according to the embodiment has a number of substrate floating pads including the substrate floating pads 40d to 40f. Further, in this drawing, the incident position of the laser beam LB on the substrate 50 is shown as a beam incident position 55 with hatching.

  In the laser processing apparatus according to the embodiment, the substrate floating pad 40e is also provided with a height control mechanism. In addition, a height detector that detects the height of the surface of the substrate 50 at the beam incident position 55 above the substrate floating pad 40e is disposed in the vicinity of the substrate floating pad 40e. In this figure, the height of the surface of the substrate 50 is detected from the lower side of the substrate 50, but may be detected from the upper side of the substrate 50.

  The height control mechanism provided on the substrate floating pad 40e moves the substrate floating pad 40e along the Z-axis direction based on the height of the surface of the substrate 50 detected by the height detector. Is made to coincide with the height of the homogenization surface of the homogenizer (the beam incident position 55 above the substrate floating pad 40e).

  In the embodiment, the driving of the substrate floating pads 40b and 40e by the height control mechanism is performed in the same manner in conjunction with each other. Depending on the type and form of laser processing, both may be driven independently in different modes.

  As shown in the figure, the laser processing apparatus according to the embodiment includes a substrate transfer means 45. The substrate transfer means 45 includes guides 43a and 43b and substrate holders 44a and 44b.

  The guides 43a and 43b extend in parallel to each other along the X-axis direction. The substrate holders 44a and 44b are supported by the guides 43a and 43b, respectively, so as to be movable in a direction parallel to the X-axis direction. The substrate holders 44a and 44b can clamp both end portions of the substrate 50 and move the clamped substrate 50 along the guides 43a and 43b in a direction parallel to the X-axis direction.

  Laser annealing using the laser processing apparatus according to the embodiment is performed as follows, for example.

  First, the height along the Z-axis direction of the substrate 50 at the beam incident position 55 is detected. Next, based on the detected height, the substrate 50 at the beam incident position 55 is moved along the Z-axis direction by bending the substrate floating pad up and down by the height control mechanism. The height control mechanism is controlled so that the height of the surface of the substrate 50 (amorphous silicon film) at the beam incident position 55 matches the height of the homogenized surface. Then, a laser beam is incident on the substrate 50 at the beam incident position 55 from the Z-axis direction, and the amorphous silicon film at the incident position is crystallized.

  The substrate transport means 45 is driven to move the substrate 50 in the negative X-axis direction. After the movement, the height of the substrate 50 along the Z-axis direction at the beam incident position 55 is detected, and the surface height of the substrate 50 at the beam incident position 55 and the height of the homogenized surface are determined in the same manner as described above. After moving so as to coincide with each other, a laser beam is irradiated to crystallize the amorphous silicon film.

  By moving the substrate 50 by the substrate transfer means 45, laser annealing of a predetermined region along the direction parallel to the X-axis direction of the substrate 50 can be performed with high quality.

  The substrate transfer means 45 moves the substrate 50 that has been air levitation. Therefore, the load applied to the drive unit that drives the substrate transport means 45 to move the substrate 50 is small. For this reason, the drive part of the board | substrate conveyance means 45 can be reduced in size.

  FIG. 4 shows a modification of the substrate transfer means.

  3 moves the substrate 50 in a one-dimensional direction (direction parallel to the X-axis direction). However, the substrate transfer means shown in FIG. 3 moves the substrate 50 in a two-dimensional direction (X-axis direction). Direction and a direction parallel to the Y-axis direction).

  The substrate transfer unit according to the modification includes an X-axis direction substrate transfer unit 72 and a Y-axis direction substrate transfer unit 75.

  The X-axis direction substrate transfer means 72 includes guides 70a and 70b and substrate holders 71a and 71b. The guides 70a and 70b extend along the X-axis direction in parallel with each other. The substrate holders 71a and 71b are supported by the guides 70a and 70b, respectively, so as to be movable in a direction parallel to the X-axis direction. The substrate holders 71a and 71b can adsorb the back surface of the substrate 50 and move the adsorbed substrate 50 along the guides 70a and 70b in a direction parallel to the X-axis direction.

  The Y-axis direction substrate transport means 75 includes guides 73a and 73b and substrate holders 74a and 74b. The guides 73a and 73b extend along the Y-axis direction in parallel with each other. The substrate holders 74a and 74b are supported by the guides 73a and 73b, respectively, so as to be movable in a direction parallel to the Y-axis direction. The substrate holders 74a and 74b can adsorb the back surface of the substrate 50 and move the adsorbed substrate 50 along the guides 73a and 73b in a direction parallel to the Y-axis direction. When the substrate 50 adsorbed by the substrate holders 74a and 74b is moved along a direction parallel to the Y-axis direction, the adsorption by the substrate holders 71a and 71b of the X-axis direction substrate transfer means 72 is released. .

  By moving the substrate 50 by the X-axis direction substrate transfer means 72 and the Y-axis direction substrate transfer means 75, laser annealing at an arbitrary position of the substrate 50 can be performed with high quality.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

  It can be generally used for laser processing in which processing is performed by controlling the height of the processing object. In particular, it can be suitably used for laser annealing in which the height of the processed substrate needs to be controlled with high accuracy.

It is the schematic which shows the laser processing apparatus by an Example. It is the schematic which shows the vicinity of a board | substrate floating pad. It is a schematic plan view of the laser processing apparatus seen from the direction parallel to the optical axis of a laser beam (Z-axis direction). It is a figure which shows the modification of a board | substrate conveyance means.

Explanation of symbols

30 Laser light sources 31a, 31b Folding mirror 32 Homogenizer 32a Focus lens 40, 40a-40f Substrate floating pad 41 Height detector 42 Height control mechanism 43a, 43b Guide 44a, 44b Substrate holder 45 Substrate transport means 50 Substrate 55 Beam incidence Position 60 Air 70a, 70b, 73a, 73b Guide 71a, 71b, 74a, 74b Substrate holder 72 X-axis direction substrate transfer means 75 Y-axis direction substrate transfer means LB Laser beam

Claims (6)

A holding mechanism for holding a workpiece to be machined in a movable manner in a direction along the workpiece surface;
A laser optical system that causes a laser beam to be incident on a partial region of the processing surface of the processing object held by the holding mechanism;
A moving mechanism for moving the object to be processed held by the holding mechanism in a direction along the surface to be processed;
A height adjustment for supporting a region where the laser beam from the laser optical system is incident on the workpiece held by the holding mechanism and displacing the supported region in the height direction with respect to the processing surface. A laser that supports a part of the processing object such that the processing object can move relative to the height adjustment mechanism in a direction along the processing surface. Processing equipment.   The laser processing according to claim 1, further comprising a height detector that detects a position of the processing object in a region where a laser beam from the laser optical system is incident with respect to a height direction of a processing surface of the processing object. apparatus.   The laser processing apparatus according to claim 1, wherein the holding mechanism floats and holds the object to be processed with a gas. The height adjustment mechanism is
Air bearings,
The laser processing apparatus of any one of Claims 1-3 including the raising / lowering mechanism which displaces the said air bearing to a height direction with respect to a to-be-processed surface. (A) displacing a portion in the path of the laser beam in a height direction with respect to the processing surface by bending a workpiece to be processed and having a flexible processing target;
(B) a step of displacing a portion in the path of the laser beam and then causing the laser beam to enter the displaced portion.   The laser processing method according to claim 5, further comprising a step of alternately repeating the steps (a) and (b) while moving the object to be processed along a surface to be processed with respect to a laser beam path. .

Images