JP2010141190A - Laser crystallization device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser crystallization device such that unevenness of irradiation power is eliminated by reducing increases in light device area and device weight and eliminating a shift in light condensation position of laser light. <P>SOLUTION: A substrate is scanned with laser light in two dimensions through two movements which is a movement of the substrate and a movement of an optical system, and while the movement of the substrate is made through a continuous scan movement in a scanning direction (for example, in an X direction) of the substrate, the movement of the optical system is made through an intermittent stepped movement in a direction (for example, in a Y direction) perpendicular to the scanning direction. Thus, the scanning with the laser light includes two operations, i.e. a scanning operation and a stepping operation and then a stage for conveying the substrate is moved in one scanning direction (for example, in the X direction), so a movement range based upon the movement of the stage is reducible to about a half as compared with a configuration for moving the stage in two scanning directions of the X direction and Y direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser crystallization apparatus, and relates to a crystallization technique in which a non-single crystalline semiconductor thin film is melted and crystallized using laser light.

  There is a technique for crystallizing an amorphous semiconductor layer formed on an insulator such as a glass substrate to obtain a crystalline semiconductor layer, and forming a thin film transistor (TFT) using the crystalline semiconductor layer as an active layer. Are known. For example, in an active matrix liquid crystal display device, a semiconductor film such as a silicon film is provided, a thin film transistor is formed on a glass substrate, and the thin film transistor is used as a switching element for switching display.

  The formation of the thin film transistor includes a crystallization step of crystallizing the non-single crystal semiconductor thin film to generate a crystallized semiconductor film. As this crystallization technique, for example, a laser crystallization technique is known in which an irradiation region of a non-single-crystal semiconductor thin film is melted and crystallized using a high-energy short pulse laser beam.

  In laser crystallization technology, one using excimer laser light as irradiation light and one using continuous wave laser light (CW laser light) are known.

  Laser crystallization using excimer laser light is performed by irradiating amorphous silicon with laser light having a uniform intensity distribution without performing phase modulation (ELA technology) and by irradiating phase-modulated excimer laser light. A technique for crystallizing (PMELA technique) is known.

  Crystallization technology (ELA) using excimer laser light has an extremely short pulse irradiation time of about 30 nsec, and a minute region can be instantaneously heated to 1000 ° C. or higher. Popular as a technology. Since the energy density per pulse is about 0.3 J / cm 2, it is necessary to perform 90 to 99% overlap irradiation. Since the processing time becomes longer due to the multiple irradiation, it is necessary to use a long beam in order to improve the throughput. Therefore, the entire surface is irradiated under the same conditions.

  In laser annealing crystallization using continuous wave laser light (CW laser light) that outputs energy continuously with respect to time, it is necessary to reduce the beam irradiation area to ensure energy density. By narrowing down, the quality of the crystallized region can be selectively controlled. As a result, energy-saving crystallization can be realized while maintaining the quality of TFT characteristics.

  In crystallization using excimer pulse laser light, the mobility is about 150 to 300 (cm 2 / Vs), for example, whereas laser annealing crystallization using continuous wave laser light (CW laser light) The degree can be realized in the range of about 400 to 600 (cm 2 / Vs), which is advantageous for forming high-performance polysilicon (see, for example, Patent Document 1).

In a crystallization apparatus using an excimer laser, a CW laser, or the like, as a technique for irradiating laser light onto a substrate to be processed, a mechanism for driving a transfer stage on which the processing target is mounted in the XY direction, laser light, A mechanism for shaking itself with a galvanometer mirror or the like is known.
Japanese Patent Laying-Open No. 2005-167084

  When a laser beam is scanned and irradiated on a substrate by a stage mechanism that drives a transfer stage on which a substrate to be processed is mounted in the XY directions, the drive range of the transfer stage requires a space at least four times the substrate size. For this reason, there is a problem that the apparatus area is enlarged and the apparatus weight is increased as the substrate size is increased.

  FIG. 9 is a diagram for explaining a driving range of a conventional transfer stage. In FIG. 9, the substrate 30 is placed on the XY transport stage 13, and the laser light source 21 is attached to a fixed gantry (gantry). Laser light irradiation is performed by mounting the substrate 30 on the fixed laser light source 21 and moving the XY transport stage 13 in the X direction and the Y direction. In order to irradiate the entire surface of the substrate 30 with laser light, the XY transport stage 13 needs to move in the range of 13a to 13d in the drawing, and requires a space at least four times the substrate size.

  Further, in order to perform high-speed continuous scanning irradiation on the substrate with continuous wave laser light (CW laser light), it is necessary to reciprocate the stage on which the substrate is placed at high speed. For example, to accelerate at an average acceleration of 0.1 G and scan the substrate at a constant speed of 2000 mm / s, it is necessary to move about 2 m in the acceleration region and about 2 m in the deceleration region. A total distance of about 4m is required.

  For example, when high-speed continuous scanning irradiation is performed on a liquid crystal glass liquid crystal substrate having a size of 730 mm × 920 mm, a stage size of about 4 m is required as the acceleration / deceleration region of about 1 m as the length of the substrate, and the stage on which this stage is installed The surface plate needs a size of about 6m when margins at both ends are added.

  Thus, when performing high-speed continuous scan irradiation by driving a stage, there are problems that the size of the stage and the stage surface plate is increased, and the installation area for installing the liquid crystal display device is also increased.

  On the other hand, when scanning irradiation is performed on the substrate by shaking the laser beam, variations in the beam condensing density and a decrease occur due to uneven irradiation speed on the substrate and deviation of the condensing position of the laser beam from the substrate surface. There is a problem.

  FIG. 10 is a diagram for explaining unevenness in the irradiation speed of the laser light and deviation of the condensing position from the substrate surface.

  In FIG. 10, when the laser beam is irradiated onto the substrate by shaking the laser beam at a constant angular velocity at the point a, the moving speed of the irradiated laser beam on the substrate is not equal, but the central portion (in the drawing) The speed at the a position) is reduced, and the speed at the peripheral side (the c position in the figure) is increased. As described above, when unevenness occurs in the irradiation speed of the laser light on the substrate, the beam condensing density is lowered, and uniform crystallization cannot be expected.

  Further, the focused position of the irradiated laser beam is not necessarily on the substrate. When the condensing position is matched with the central part (position a in the figure), no light is collected on the substrate on the peripheral side (position c in the figure), and the condensing position is the front position of the board (position b in the figure). ) On the other hand, when the condensing position is adjusted to the peripheral side, the condensing position is the rear position of the substrate in the center (not shown). As described above, when the condensing position is deviated from the surface of the substrate, the beam condensing density is lowered, the irradiation power of the laser light becomes non-uniform, and uniform crystallization cannot be expected.

  Therefore, the present invention solves the above-described conventional problems, and in a crystallization apparatus using laser light irradiation, the apparatus area is enlarged and the weight of the apparatus is increased, the laser light condensing position is shifted, and the irradiation power is reduced. An object of the present invention is to solve the problem of uniformity, reduce an increase in apparatus area and apparatus weight, eliminate the deviation of the laser beam focusing position, and eliminate unevenness in irradiation power.

  The present invention is divided into two movements, the movement of the substrate and the movement of the optical system, when the laser beam is scanned two-dimensionally on the substrate. The movement of the substrate is in the scanning direction of the substrate (for example, the X direction). The optical system is moved by intermittent step movement in a direction orthogonal to the scanning direction (for example, Y direction). By adopting a configuration in which the scanning of the laser beam is performed by two operations, a scanning operation and a step operation, the stage moves so that the moving direction of the stage carrying the substrate is only one scanning direction (for example, the X direction). The moving range can be reduced, and the moving range can be reduced to about ½ as compared with the configuration in which the stage has two scanning directions of the X direction and the Y direction.

  Further, according to the present invention, an optical system for emitting laser light is provided in the gantry, and the optical system is moved relative to the gantry, or the gantry with the optical system is moved. With this configuration, the positional relationship between the optical system and the stage is not changed by the moving operation and is kept constant, so that it is possible to suppress the occurrence of a focal position shift and make the laser irradiation power uniform. .

  Further, since the optical system can be moved step by step during the stage folding operation, the process tact time required for scanning can be shortened.

  A laser crystallization apparatus according to the present invention includes a stage on which a substrate is placed, an optical system that emits laser light toward the stage, and a stage that continuously scans the stage in a reciprocating manner along the scanning direction of the laser light. A scanning mechanism; and an optical system step feeding mechanism that intermittently steps the optical system in a direction orthogonal to the scanning direction with a predetermined step width.

  The laser crystallization apparatus of the present invention crystallizes a substrate by two-dimensionally irradiating a laser beam on the substrate by a stage scan movement by a stage scanning mechanism and an optical system step movement by an optical system step feed mechanism. .

  The optical system step feed mechanism of the present invention includes a gantry having a beam member extending in the direction perpendicular to the scanning direction at an upper position of the stage and a step driving unit.

  In one form of the optical system step feed mechanism, an optical system is slidably mounted on a girder member of a gantry, and a step driving unit moves the optical system stepwise in a direction orthogonal to the scanning direction.

  In another form of the optical system step feed mechanism, the optical system is fixedly attached to a predetermined position of the beam member of the gantry, and the step drive unit steps the gantry in a direction perpendicular to the scanning direction to move the optical system. Step moves in a direction perpendicular to the scanning direction.

  The stage scanning mechanism and the optical system step feed mechanism of the present invention are driven and controlled by a drive control unit. The drive control unit performs the step movement by the amount of movement of the step width determined in the optical system step feeding mechanism during the operation of reversing the moving direction of the stage scanning mechanism. As a result, the optical system is stepped during the stage folding operation, thereby shortening the process tact time required for scanning.

  The optical system attached to the gantry of the present invention can be a laser light source or a laser emitting unit connected to the laser light source via an optical fiber. When attaching the laser emitting part to the gantry, the positional relationship between the laser emitting part and the laser light source changes when the laser emitting part is moved relative to the gantry or when the gantry itself to which the laser emitting part is attached is moved. However, since the laser emitting portion and the laser light source are connected by an optical conductor such as an optical fiber, troubles due to movement can be avoided.

  According to the present invention, an increase in device area and device weight can be reduced. In addition, it is possible to eliminate the deviation of the condensing position of the laser beam and to eliminate the unevenness of the irradiation power.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram for explaining a configuration example of a laser crystallization apparatus of the present invention.

  In FIG. 1, a laser crystallization apparatus 1 of the present invention includes a substrate stage 10 on which a substrate 30 to be processed is placed, an optical system 20 that emits laser light toward the substrate stage 10, and a transport provided in the substrate stage 10. The stage scanning mechanism 2 that scans and moves the stage 11 (X stage) continuously in a reciprocating manner along the scanning direction of the laser beam, and the optical system 20 are stepped intermittently at a predetermined step width in a direction orthogonal to the scanning direction. And an optical system step feed mechanism 3.

  The laser crystallization apparatus 1 irradiates a laser beam two-dimensionally on the substrate 30 by the scanning movement of the transport stage 11 by the stage scanning mechanism 2 and the step movement of the optical system 20 by the optical system step feed mechanism 3. 30 is annealed and crystallized. The substrate stage 10 may include a Z stage 12 that changes the height of the placed substrate 30 in addition to the transport stage 11 that transports the placed substrate 30.

  The stage scan mechanism 2 includes a scan drive unit 2 a that scans and moves the transport stage 11. The scan driving unit 2a continuously scans and moves the transport stage 11 along the scanning direction of the laser beam, and can also reverse the moving direction of the transport stage 11 and reverse the moving direction of the transport stage 11. Thus, the transfer stage 11 can be reciprocated.

  During the scanning movement of the transport stage 11 by the stage scanning mechanism 2, the laser light emitted from the optical system 20 scans the laser light along the scanning direction on the substrate 30 mounted on the transport stage 11. Crystallize.

  The optical system step feed mechanism 3 scans the optical system 20 with a gantry 3b having a beam member 3c extending in the direction (Y direction) perpendicular to the scanning direction (X direction) at the position above the transport stage 11. A step drive unit 3a that performs step movement in a direction (Y direction) orthogonal to the direction (X direction).

  After the transfer stage 11 is moved to one end by the stage scanning mechanism 2, the transfer stage 11 is reversed in the same scanning direction (X direction). At this time, the optical system step feed mechanism 3 moves the optical system 20 stepwise in a direction (Y direction) orthogonal to the scanning direction (X direction) by a predetermined scan width. By this step movement, the optical system 20 is ready for laser light irradiation on the next scanning line, and the stage scanning mechanism 2 again moves the transport stage 11 in the moving direction opposite to the previous scanning. By this movement of the transport stage 11, the substrate 30 is irradiated with laser light on a scanning line adjacent to the previous scanning line of laser light.

  The present invention includes two forms as the step drive unit 3 a of the optical system step feed mechanism 3.

  The first form of the step drive unit 3a of the optical system step feed mechanism 3 is configured to move the optical system 20 in steps. In the first embodiment, the optical system 20 is slidably mounted on the beam member 3c of the gantry 3b. The step drive unit 3a moves the optical system 20 stepwise along the beam member 3c with a predetermined step width.

  The movement direction of the step movement of the step driving unit 3a is a direction (Y direction) orthogonal to the scanning direction (X direction) by the stage scanning mechanism 2, and the step movement is performed by a predetermined step width in this direction.

  The second form of the step drive unit 3a of the optical system step feed mechanism 3 is configured to move the optical system 20 stepwise together with the gantry 3b. In the second embodiment, the optical system 20 is fixedly mounted on the beam member 3c of the gantry 3b. The step driving unit 3a steps the optical system 20 attached to the beam member 3c of the gantry 3b by step-moving the gantry 3b with a predetermined step width.

  The moving direction of the step movement of the step driving unit 3a is the direction (Y direction) orthogonal to the scanning direction (X direction) by the stage scanning mechanism 2 as in the first embodiment, and the step is predetermined in this direction. Step by step in the width.

  The scan driving unit 2 a of the stage scanning mechanism 2 receives the drive signal output from each axis driver 6 and moves the transport stage 11. Each axis driver 6 is controlled by a control signal from the drive control unit 5.

  Each axis driver 6 outputs a drive signal for driving the Z stage 12 in addition to the transport stage 11, and adjusts the height of the Z stage 12 by a drive unit (not shown). The focal position of the laser beam can be aligned with the surface of the substrate 30 by adjusting the height of the Z stage 12. The height adjustment by the Z stage 12 is not necessarily required for the laser beam scanning operation, and the alignment of the focal position of the laser beam can be adjusted by an optical system (not shown).

  The step drive unit 3 a of the optical system scan feed mechanism 3 is controlled by a control signal from the drive control unit 5.

  The drive control unit 5 controls the operation of reversing the moving direction of the stage scanning mechanism 2, and during this reversing operation, moves the step by the amount of movement of the step width determined in the optical system step feed mechanism 3. To control. As a result, the drive control unit 5 controls the drive of the scan drive unit 2a of the stage scan mechanism 2 and the step drive unit 3a of the optical system step feed mechanism 3 to two-dimensionally direct the laser beam on the substrate 30 in the XY directions. Irradiate.

  The drive control unit 5 is controlled by the host control unit 4. The host controller 4 controls the overall operation of the laser crystallization apparatus in addition to controlling the drive controller 5.

  The optical system 20 can be a laser light source 21 or a laser light emitting unit 22 connected to the laser light source via an optical fiber (not shown).

  FIG. 2 is a view for explaining scanning of laser light by the laser crystallization apparatus of the present invention. 2A shows scanning movement by the stage scanning mechanism 2 and step movement by the optical system step feed mechanism 3, and FIG. 2B shows a locus of laser light on the substrate 30. FIG.

  FIG. 2A shows an example in which the horizontal direction in the figure is the stage scanning direction a (X direction) and the vertical direction is the step feed direction b (Y direction).

  The stage 11 is moved by the stage scanning mechanism 2 in the stage scanning direction a1. At this time, since the optical system 20 is fixed, the laser light emitted from the optical system 20 moves on the substrate 30 in the direction opposite to the movement direction of the transport stage 11 (direction A1 in the drawing) by the scanning movement. It will be.

  While the transfer stage 11 is scanned to one end, the laser beam can be scanned on one line. When the transfer stage 11 reaches one end, scanning of the laser beam on one line is completed. At the end position, the optical system step feed mechanism 3 moves the optical system 20 stepwise in the downward direction in FIG. 2A (the b direction in FIG. 2A). By this step operation, the laser beam emitted from the optical system 20 is step-moved on the substrate 30 in the same direction as the movement direction of the optical system 20 (direction B in the drawing). By this step movement, the optical system 20 is ready to scan the laser beam on the next line.

  Thereafter, the stage 11 is moved by the stage scanning mechanism 2 in the stage scanning direction a2. By this scanning movement, the laser light emitted from the optical system 20 moves on the substrate 30 in the direction opposite to the movement direction of the transport stage 11 (direction A2 in the drawing).

  By repeating the scanning movement of the transfer stage 11 by the stage scanning mechanism 2 and the step movement of the optical system 20 by the optical system step feeding mechanism 3, the laser beam is scanned two-dimensionally on the substrate 30.

  Next, configuration examples of the stage scanning mechanism 2 and the optical system step feed mechanism 3 according to the present invention will be described with reference to FIGS. 3 to 6, and operation examples will be described with reference to the flowchart of FIG. 7 and the timing chart of FIG. 8. . 3 and 4 show a first configuration example, and FIGS. 5 and 6 show a second configuration example.

  First, a first configuration example of the stage scanning mechanism and the optical system step feeding mechanism of the present invention will be described.

  FIG. 3 is a schematic perspective view of a first configuration example of the stage scanning mechanism and the optical system step feeding mechanism. The stage scan mechanism 2A includes a scan drive unit 2a that scans and moves the transport stage 11 in the X direction. In the optical system step feed mechanism 3A, a gantry 3b including a beam member 3c extending in the Y direction orthogonal to the X direction is installed at a position above the transport stage 11, and the beam member 3c is stepped in the Y direction. A step driving unit 3a is provided. The beam member 3c is installed so that the distance from the transfer stage 11 is constant.

  The optical system 20 is a mechanism that emits laser light onto a substrate 30 that is a processing target placed on the transport stage 11, and can be a laser light source 21 or a laser light emitting unit 22.

  FIG. 3A shows an example in which the optical system 20 is configured by a laser light source 21, and FIG. 3B shows an example in which the optical system 20 is configured by a laser light emitting unit 22. The laser light source 21 emits laser light from a power source (not shown). The laser light emitting unit 22 receives and emits laser light transmitted from a laser light source (not shown) through an optical fiber 23.

  The optical system 20 is moved stepwise in the Y direction by the step driving unit 3a along the beam member 3c of the gantry 3b. By moving the optical system 20 along the beam member 3c, the distance from the transport stage 11 is kept constant. Thereby, the focal position of the laser light emitted from the optical system 20 can always be on the substrate 30 regardless of the step movement.

  In this step movement, the movement is performed with a predetermined step width. This step width can be determined by the distance between the laser beam and the adjacent scanning line in scanning.

  FIG. 4 is a schematic plan view of a first configuration example of the stage scanning mechanism and the optical system step feeding mechanism. The transport stage 11 scans in the X direction by the stage scanning mechanism 2A, and the optical system 20 steps in the Y direction by the optical system step feed mechanism 3A. Laser light is irradiated two-dimensionally onto the substrate 30 placed on the transport stage 11 by the scanning movement of the transport stage 11 in the X direction and the step movement of the optical system 20 in the Y direction.

  Next, a second configuration example of the stage scanning mechanism 2 and the optical system step feeding mechanism 3 according to the present invention will be described.

  FIG. 5 is a schematic perspective view of a second configuration example of the stage scanning mechanism and the optical system step feeding mechanism. The stage scan mechanism 2B has the same configuration as the stage scan mechanism 2A described above, and includes a scan drive unit 2a that scans and moves the transport stage 11 in the X direction. In the optical system step feed mechanism 3B, a gantry 3b including a beam member 3c extending in the X direction is installed at a position above the transport stage 11, and an optical system 20 is fixed to the beam member 3c. The gantry 3b is capable of step movement freely in the Y direction orthogonal to the X direction by the step drive unit 3a. The beam member 3c is installed so that the distance from the transfer stage 11 is constant.

  The optical system 20 is a mechanism that emits laser light onto the substrate 30 that is a processing target placed on the transport stage 11, as in the case of the stage scanning mechanism 2 </ b> A, and is a laser light source 21 or a laser light emitting unit 22. It can be.

  In the configuration in which the laser light source 21 is installed, laser light is emitted by a power source (not shown), and in the configuration in which the laser light emitting unit 22 is installed, laser light transmitted from a laser light source (not shown) is received via an optical fiber. Eject.

  The optical system 20 is moved stepwise in the Y direction together with the gantry 3b by the step drive unit 3a. By moving the optical system 20 while being fixed on the beam member 3c, the distance from the transport stage 11 is kept constant. Thereby, the focal position of the laser light emitted from the optical system 20 can always be on the substrate 30 regardless of the step movement.

  In this step movement, the movement is performed with a predetermined step width. This step width can be determined by the distance between the laser beam and the adjacent scanning line in scanning.

  FIG. 6 is a schematic plan view of a second configuration example of the stage scanning mechanism and the optical system step feeding mechanism. The transport stage 11 is scanned and moved in the X direction by the stage scanning mechanism 2B, and the optical system 20 is stepped in the Y direction by the optical system step feed mechanism 3B. Laser light is irradiated two-dimensionally onto the substrate 30 placed on the transport stage 11 by the scanning movement of the transport stage 11 in the X direction and the step movement of the optical system 20 in the Y direction.

  Next, an example of scanning operation of laser light by the laser crystallization apparatus of the present invention will be described with reference to FIG.

  First, the substrate is mounted on the transfer stage (S1), and the transfer stage and the optical system are moved to the initial positions. The movement to the initial position can be performed based on a command signal output from the drive control unit. The drive control unit stores various data when the substrate is scanned with laser light such as the initial position of the transfer stage, the substrate size of the substrate to be processed, the interval between the laser beams to be irradiated, and the scanning speed of the laser light. (Not shown), and based on this data, the position coordinates of the initial position, the position coordinates at which the conveyance stage is turned back, the scan speed, the step width, and the like are calculated, and the drive signal and step of the scan drive unit are calculated. A signal for controlling each part such as a drive signal of the drive part is generated (S2).

  After the transport stage and the optical system are moved to the initial positions, the scanning movement of the transport stage is started with the position of the optical system fixed. After starting the scanning operation of the transfer stage, the irradiation of the laser beam to the substrate is stopped until the transfer stage moves and the laser beam reaches the position to irradiate the substrate. Is prevented from irradiating the substrate and the apparatus by the laser beam. This laser beam irradiation stop control is performed by, for example, stopping the irradiation of the laser beam outside the irradiation region by a process such as blocking the laser beam optical path by a shutter and guiding the laser beam to a dummy material by a mirror. (S3).

  After the transport stage reaches a predetermined position (S4), irradiation of the laser beam onto the substrate is started. The start of the laser beam irradiation can be performed by, for example, opening the shutter that has been shut off, or performing processing such as guiding the laser beam from the dummy material to the substrate side using a mirror (S5).

  By continuing the scanning operation of the transfer stage with the position of the optical system fixed, the laser beam is irradiated and scanned on one line in the X direction on the substrate. This laser light irradiation is continued in the effective area of the substrate. The substrate effective area is a region where crystallization is performed in the substrate, and is determined by a line irradiated with laser light in the scan movement. After passing the end of the line, which is the effective area of the substrate by the scanning operation (S6), when the transfer stage reaches the return position (S7), it performs the return operation to reverse the direction of movement of the transfer stage and the optical system Stepping is performed to prepare for irradiation with laser light on the next line (S8).

  The reason why the effective substrate area of S6 and the folding position of S7 are provided separately is that within the effective substrate area, it is necessary to scan the carriage stage at a constant speed and decelerate after leaving the effective substrate area. This is because a predetermined distance is required after the transfer stage is accelerated to reach a predetermined transfer speed. The position of the substrate effective area and the position of the return may be determined using a position sensor in addition to determining based on a control signal from the drive control unit.

  In S8, after the operation of folding the transport stage and the step movement of the optical system is completed (S9), the processes of S6 to S9 are repeated until the entire scanning of the laser beam on the substrate is completed. Whether or not the entire scanning of the laser beam has been completed can be determined based on whether or not the position of the transport stage and the position of the optical system have reached the final position, and this determination is based on a control signal from the drive control unit. In addition, the position sensor may be used for detection (S10).

  Next, the relationship between the operation and position of the transport stage and the optical system will be described with reference to FIG. FIG. 8A shows the scanning operation of the transfer stage, FIG. 8B shows the reversing operation of the transfer stage, and FIG. 8C shows the position of the transfer stage. FIG. 8D shows the step operation of the optical system, FIG. 8E shows the position of the optical system, and FIG. 8F shows laser light irradiation.

  The transfer stage repeats the movement of one line in the X direction by the scanning operation (FIG. 8A) and the reversing operation (FIG. 8B). In this repetition, the position of the transfer stage (FIG. 8C) increases linearly by the scanning operation and then reverses and decreases linearly by the next scanning operation. By repeating this operation, the entire surface of the substrate is scanned with laser light.

  The optical system moves by one step in the Y direction by the step operation while the transfer stage performs the reversing operation (FIG. 8D). By this step operation, the position in the Y direction increases stepwise with the step width as a unit (FIG. 8E).

  The laser beam irradiation is performed within a laser beam irradiation range set while the transport stage performs a scanning operation. This laser beam irradiation range can be set, for example, in a portion where the conveyance stage is in a constant speed range except for an acceleration / deceleration range when the scanning operation starts and stops.

  According to the aspect of the present invention, it is possible to irradiate a laser beam having a uniform energy density over the entire substrate surface, uniform crystallization quality, and uniform TFT characteristics.

  According to the aspect of the present invention, the size of the substrate stage and the surface plate that supports the substrate stage can be reduced, and the installation area of the crystallization apparatus can be reduced.

It is the schematic for demonstrating the structural example of the laser crystallization apparatus of this invention. It is a figure for demonstrating the scanning of the laser beam by the laser crystallization apparatus of this invention. It is a perspective view for demonstrating the 1st structural example of the stage scan mechanism and optical system step feed mechanism of this invention. It is a top view for demonstrating the 1st structural example of the stage scan mechanism and optical system step feed mechanism of this invention. It is a perspective view for demonstrating the 2nd structural example of the stage scan mechanism and optical system step feed mechanism of this invention. It is a top view for demonstrating the 2nd structural example of the stage scan mechanism and optical system step feed mechanism of this invention. It is a flowchart for demonstrating operation | movement of the stage scan mechanism and optical system step feed mechanism of this invention. It is a timing diagram for demonstrating operation | movement of the stage scan mechanism and optical system step feed mechanism of this invention. It is a figure for demonstrating the drive range of the conventional conveyance stage. It is a figure for demonstrating the nonuniformity of the irradiation speed of a laser beam, and the shift | offset | difference from the substrate surface of a condensing position.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Laser crystallization apparatus, 2 ... Stage scan mechanism, 2A ... Stage scan mechanism, 2B ... Stage scan mechanism, 2a ... Scan drive part, 3, 3A, 3B ... Optical system step feed mechanism, 3a ... Step drive part, 3b ... Gantry, 3c ... Girder part, 4 ... Upper control part, 5 ... Drive control part, 6 ... Each axis driver, 10 ... Substrate stage, 11 ... Transport stage, 12 ... Z stage, 13 ... XY transport stage, 20 ... Optical system, 21... Laser light source, 22... Laser light emitting section, 23.

Claims (5)

A stage on which a substrate is placed;
An optical system for emitting laser light toward the stage;
A stage scanning mechanism that continuously and reciprocally scans the stage along the scanning direction of the laser beam;
An optical system step feed mechanism that intermittently steps the optical system in a direction perpendicular to the scanning direction with a predetermined step width;
A laser crystal characterized in that the substrate is crystallized by two-dimensionally irradiating a laser beam onto the substrate by the stage scan movement by the stage scan mechanism and the optical system step movement by the optical system step feed mechanism. Device. The optical system step feed mechanism is
A gantry having a beam member that extends the optical system in a direction perpendicular to the scanning direction at a position above the stage;
A step drive unit for step-moving an optical system slidably mounted on the gantry girder member;
2. The laser crystallization apparatus according to claim 1, wherein the optical system is stepped in a direction orthogonal to a scanning direction by step movement of the step driving unit. The optical system step feed mechanism is
A gantry having a beam member that extends the optical system in a direction perpendicular to the scanning direction at a position above the stage;
A step drive unit for step-moving the beam member of the gantry,
2. The optical system is fixed to a predetermined position of a beam member of the gantry, and the optical system is stepped in a direction orthogonal to a scanning direction by the movement of the gantry by a step movement of a step driving unit. The laser crystallization apparatus described in 1. A drive control unit for controlling the drive of the stage scan mechanism and the optical system step feed mechanism;
The drive control unit performs step movement by an amount of movement of a step width defined in the optical system step feeding mechanism during an operation of reversing the moving direction of the stage scanning mechanism. The laser crystallization apparatus according to any one of 1 to 3.   5. The laser crystallization apparatus according to claim 1, wherein the optical system is a laser light source or a laser emission unit connected to the laser light source via an optical fiber.