JP2005285896A - Method of automatically adjusting irradiation distance and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of automatically adjusting an irradiation distance that shortens a laser irradiation processing time, and reduces the space where a distance sensor is installed. <P>SOLUTION: The apparatus for automatically adjusting an irradiation distance comprises an elevation driving device 30 for moving a stage 10 up and down; a single distance sensor 31, provided on a laser oscillation device 1 side, for changing and isolating a scan axis line x from a position, from which a pulse laser 4 irradiates the irradiated object 5, to the backside of a traveling direction of a stage 10, measuring a distance h between an irradiation position of the laser 4 and the irradiated surface of the irradiated object 5, which is apart from the irradiation position by a distance corresponding to a predetermined traveling distance L, and outputting a detected value hn; and a basic control value setting means 32 for outputting a basic control value H corresponding to an appropriate value between the irradiated object 5 and an objective 3. A difference value Δn between the basic control value H and the detected value hn is continuously obtained, a control difference value δ derived from a difference between the previously obtained difference value Δn-1 and the difference value Δn obtained thereafter is obtained, the elevation driving device 30 is driven in response to the control difference value δ, and thereby the distance is controlled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an irradiation distance automatic adjustment method and apparatus therefor, and more specifically, an irradiation distance automatic adjustment method between an objective lens for focusing a pulse laser from a laser oscillation apparatus and an irradiation object placed on a stage, and It relates to the device.

  Conventionally, for example, when manufacturing crystallized silicon for a thin film transistor, an irradiated object in which a thin a-Si (amorphous silicon) film is formed on a glass substrate is irradiated with laser light to crystallize the a-Si film to form a thin p- Si (polysilicon) film is used. As one method of irradiating the a-Si film with laser light, a uniform intensity laser light is applied to a reticle (mask) and projected onto the a-Si film of the irradiated object with an objective lens of an optical device. A method of forming an image and irradiating it is known.

  This is because the laser beam generated by a laser oscillation device that generates an excimer laser is guided to an optical device, and the direction is appropriately changed by a reflecting mirror, and after shaping and uniforming the intensity, the reticle and objective lens It is shaped into a square line beam (pulse laser) by passing through, and the object is irradiated and transferred. The irradiated object is installed in a processing chamber in a vacuum atmosphere or a nitrogen atmosphere of a laser annealing apparatus.

  In the case of irradiating a laser while relatively moving such an object to be irradiated, as described in Patent Document 1, as a method of faithfully forming an image of a reticle on an object to be irradiated with an objective lens, a pulse laser is used. A method of installing a distance sensor at a position away from the optical axis is known. This is a method that does not change the size of the image formed on the irradiated object. The distance between the reticle and the objective lens is kept constant, and the irradiated object is irradiated from the objective lens by changing the position of the irradiated object. An image is formed on the irradiated object with an appropriate distance to the object.

That is, as shown in FIG. 6, a laser oscillation device 1, a stage 10 on which an object 5 is placed, and a moving device 20 that moves the stage 10 relative to the laser oscillation device 1 in the X-axis direction are provided. And the irradiation distance automatic adjustment for irradiating the irradiation object 5 placed on the stage 10 with the pulse laser 4 from the laser oscillation device 1 which is sequentially focused through the objective lens 3 and focused by the objective lens 3 at predetermined intervals. In the method
A raising / lowering driving device 30 for moving the stage 10 up and down relatively with respect to the laser oscillation device 1, the reticle 21 and the objective lens 3;
Provided on the side of the laser oscillation device 1 on the base 22 side at a predetermined distance L1 from the irradiation position of the pulse laser 4 to the irradiated object 5 and behind the stage 10 in the traveling direction. The distance h from the irradiation surface of the pulse laser 4 is measured one after another, and the distance sensor 131 that outputs the detection value hn corresponds to an appropriate distance between the object 5 placed on the stage 10 and the objective lens 3. Basic control value setting means 32 for outputting a basic control value H to be
A difference value Δn between the basic control value H and the detected value hn is obtained one after another, and a control difference value δ consisting of a difference between the previously obtained difference value Δn−1 and the next obtained difference value Δn is obtained. The control difference value δ is output after being delayed by the time required for the stage 10 to move the predetermined distance L1,
By driving the lifting / lowering driving device 30 according to the control difference value δ, the pulse of the object 5 placed on the objective lens 3 and the stage 10 is maintained while the distance between the reticle 21 and the objective lens 3 is kept constant. It is an irradiation distance automatic adjustment method characterized by controlling the distance to the irradiation surface of the laser 4.

Therefore, when irradiating the laser while relatively moving the object to be irradiated, a distance sensor is installed at a position away from the optical axis of the pulsed laser, while keeping the distance between the reticle and the objective lens constant, By relatively changing the position of the irradiated object, the distance from the objective lens to the irradiated surface of the irradiated object is adjusted and corrected so as to be appropriate and constant, and the reticle image is satisfactorily covered by the objective lens. An image can be formed on the irradiated object. As a result, it is possible to obtain a high-quality product by relatively accurately irradiating the irradiated object with the pulse laser.
JP 2003-282477 A

  The distance sensor 131 is provided on the laser oscillation device 1 side, and the distance h from the irradiation surface of the pulse laser 4 of the irradiated object 5 at a position separated from the irradiation position of the pulse laser 4 by a predetermined distance L1 by the moving device 20. Are measured one after another, and a detection value hn is output. In the plan view shown in FIG. 7, the detection value hn is disposed on the same scan axis x as the irradiation position of the pulse laser 4, and the pulse laser 4 The scan axis line x and the scan axis line x to the irradiation object 5 are not different from each other. Accordingly, the distance sensor 131 measures the distance h on one scan axis x where the pulse laser 4 is actually irradiated.

  For this reason, a reciprocating scanning method in which the pulse laser 4 is irradiated in a reciprocating manner is adopted to measure the distance h on the entire surface of the irradiation object 5 (or the irradiation range of the irradiation object 5), that is, on all the scan axes x. In this case, distance sensors 131 (S1, S2) must be provided before and after the irradiation position of the pulse laser 4, respectively, and the number of distance sensors 131 is not only two but two distance sensors 131 (S1). , S2) needs to be secured. Specifically, the distance sensor 131 (S1, S2) is symmetrically applied to the irradiation position of the pulse laser 4 on the irradiation object 5, that is, from the optical axis of the reticle 21 and the objective lens 3 to both the front and rear sides in the traveling direction of the stage 10. Therefore, the structure becomes complicated.

  In addition, when the dedicated distance sensors 131 (S1, S2) are used for the forward path and the return path, it is not only necessary to switch the distance sensors 131 (S1, S2) used for the forward path and the return path, but also the irradiated object. 5, when the distance h is measured by the distance sensor 131 (S1, S2) for each of the outward path and the return path, the two distance sensors 131 (S1, S2) are measured so that the same value is obtained. The value needs to be calibrated, which complicates.

  Further, when the distance sensor 131 (S1, S2) is used to measure from the end of the irradiation object 5 (or the irradiation range of the irradiation object 5), the laser irradiation position is determined from the measurement position by the distance sensor 131 (S1, S2). The irradiated object 5 has to be relatively moved by an extra distance up to (4), which requires a lot of useless irradiation processing time. That is, in FIG. 6, since the distance sensor 131 starts measurement from the distance h of the left end portion of the irradiated object 5, the pulse laser 4 starts irradiation from a position separated from the left end of the irradiated object 5 by the distance L1. . Therefore, when two distance sensors 131 (S1, S2) are provided and a reciprocating scanning method in which the pulse laser 4 is emitted in a reciprocating manner is adopted, a place deviated from the irradiated object 5 serving as each front end portion of the forward path and the return path This is accompanied by an extra irradiation process (parts D1 and D2 indicated by hatching in FIG. 8), which increases the useless irradiation process time.

  The present invention has been made to solve such a conventional technical problem, and from the irradiation position of the pulse laser 4 on the scan axis x of the object 5 to be irradiated to the rear side in the traveling direction of the stage 10. Automatic adjustment of the irradiation distance with a short distance between the scanning axes and by providing only one distance sensor in a direction substantially perpendicular to the scanning direction of the laser in the irradiation range. Its purpose is to provide a method.

The configuration of the present invention is as follows.
The invention of claim 1 includes a laser oscillation device 1, a stage 10 on which an object 5 is placed, and a moving device 20 that relatively moves the stage 10 in the X-axis direction and the Y-axis direction orthogonal to the laser oscillation device 1. With
The reticle 21 and the objective lens 3 are sequentially moved while the stage 10 is moved in the forward direction in the X-axis direction and then moved in the Y-axis direction according to the scan interval y to continuously move the return path in the X-axis direction. In a method for automatically adjusting the irradiation distance, the pulse laser 4 from the laser oscillation device 1 focused through the objective lens 3 is irradiated onto the scan axis x of the irradiation object 5 placed on the stage 10 at predetermined intervals. ,
A raising / lowering driving device 30 for moving the stage 10 up and down relatively with respect to the laser oscillation device 1, the reticle 21 and the objective lens 3;
Provided on the laser oscillation device 1 side, the scan axis x is different from the irradiation position of the pulse laser 4 on the scan axis x of the irradiated object 5 on the scan axis x and moved backward in the direction of travel of the stage 10, and the movement The distance h between the irradiation object 5 and the irradiation surface of the pulse laser 4 at a position separated from the irradiation position of the pulse laser 4 by a distance corresponding to the predetermined distance L by the apparatus 20 is measured one after another, and a detection value hn is obtained. A single distance sensor 31 to output;
Basic control value setting means 32 for outputting a basic control value H corresponding to an appropriate distance between the irradiation object 5 placed on the stage 10 and the objective lens 3;
A difference value Δn between the basic control value H and the detected value hn is obtained one after another, and a control difference value δ consisting of a difference between the previously obtained difference value Δn−1 and the next obtained difference value Δn is obtained. The control difference value δ is output with a delay according to the time required for the stage 10 to move the predetermined distance L,
By driving the lifting / lowering driving device 30 according to the control difference value δ, the pulse of the object 5 placed on the objective lens 3 and the stage 10 is maintained while the distance between the reticle 21 and the objective lens 3 is kept constant. It is an irradiation distance automatic adjustment method characterized by controlling the distance to the irradiation surface of the laser 4.
The invention of claim 2 includes a laser oscillation device 1, a stage 10 on which an object 5 is placed, and a moving device 20 that relatively moves the stage 10 in the X-axis direction and the Y-axis direction orthogonal to the laser oscillation device 1. And moving the stage 10 in the X-axis direction and then displacing the stage 10 in the Y-axis direction according to the scan interval y to continuously move the X-axis direction in the X-axis direction. 3 is sequentially irradiated with a pulse laser 4 from the laser oscillation device 1 focused by the objective lens 3 onto the scanning axis x of the object 5 placed on the stage 10 at predetermined intervals. In the adjustment device,
A raising / lowering driving device 30 for moving the stage 10 up and down relatively with respect to the laser oscillation device 1, the reticle 21 and the objective lens 3;
Provided on the laser oscillation apparatus 1 side, the scan axis line x is different from the irradiation position of the pulse laser 4 on the scan axis line x of the irradiated object 5 to the rear side in the traveling direction of the stage 10, and the movement The distance h from the irradiation surface of the pulse laser 4 of the irradiated object 5 at a position separated from the irradiation position of the pulse laser 4 by a distance corresponding to the predetermined distance L by the apparatus 20 is measured one after another, and the detected value hn is obtained. A single distance sensor 31 to output;
Basic control value setting means 32 for outputting a basic control value H corresponding to an appropriate distance between the irradiation object 5 placed on the stage 10 and the objective lens 3;
First calculating means 33 for successively obtaining a difference value Δn between the basic control value H and the detected value hn;
Storage means 35 for storing the previously obtained difference value Δn−1;
A second calculating means 36 for obtaining a control difference value δ comprising a difference between the previously obtained difference value Δn−1 and the next obtained difference value Δn;
Delay means 34 for outputting the control difference value δ with a delay in accordance with the time required for the stage 10 to move the predetermined distance L;
The raising / lowering driving device 30 is driven according to the control difference value δ, and the pulse laser 4 of the irradiation object 5 placed on the objective lens 3 and the stage 10 is maintained while keeping the distance between the reticle 21 and the objective lens 3 constant. It is an irradiation distance automatic adjustment device characterized by controlling the distance to the irradiation surface.
According to the third aspect of the present invention, the delay means 34 is constituted by the first FIFO memory 45, and the detection value hn is output after being delayed according to the time required for the stage 10 to move the predetermined distance L. 3. The irradiation distance automatic adjustment device according to claim 2, wherein the output of the control difference value δ is delayed.
The invention according to claim 4 is the irradiation distance automatic adjusting device according to claim 2 or 3, wherein the storage means 35 is constituted by the second FIFO memory 46.

  According to the first and second aspects, the reciprocating scanning method in which the pulse laser 4 is irradiated in a reciprocating manner only by providing the single distance sensor 31 with respect to the irradiation position of the pulse laser 4 is employed. The distance h on the entire surface, that is, on all the scan axes x can be measured. As a result, the number of distance sensors 31 is reduced, switching between a plurality of distance sensors 31 to be used and calibration of measured values are not required, and the structure is remarkably simplified. In addition, since only one distance sensor 31 is required, the installation space, and thus the volume of the processing chamber that accommodates the stage 10 can be reduced.

  Furthermore, it is possible to reduce the measurement by the extra distance sensor 31 and the irradiation of the pulse laser 4 to a place off the irradiated object 5, and the measurement / irradiation processing time can be shortened.

  1 to 5 show an embodiment of an automatic irradiation distance adjusting device according to the present invention. 2 and 4, reference numeral 10 denotes a stage. As shown in FIG. 2, the stage 10 is moved from the laser oscillation device 1 by the moving device 20 with the irradiated object 5 made of a substrate placed on the stage 10. Relative movement is performed in the X-axis direction and the Y-axis direction orthogonal to the pulse laser 4.

  The laser oscillation device 1 is fixed to a base 22 as shown in FIG. 4A, generates an excimer laser composed of a pulsed laser, and the generated laser light A1 includes an optical system including a reticle 21 and an objective lens 3. The light is guided to the device 9, changed in direction by the reflection mirror 7, shaped through the long axis homogenizer 2 a and the short axis homogenizer 2 b to equalize the intensity, and then again changed in direction by the reflection mirror 8, the reticle 21 and the objective lens 3. By passing through, the laser beam is shaped into a pulse laser 4 composed of a square line beam, and irradiated so as to be projected and imaged onto the irradiated object 5 placed on the stage 10. The reticle 21 and the objective lens 3 are arranged with their optical axes aligned and fixed at a predetermined interval, and this optical axis (Z-axis direction) is orthogonal to the irradiation surface of the irradiated object 5. The irradiated object 5 is installed in a processing chamber in a vacuum atmosphere or a nitrogen atmosphere of a laser annealing apparatus.

  As shown in FIG. 4, the irradiated object 5 is formed by forming a thin a-Si (amorphous silicon) film 5a on a glass substrate 6. By irradiating the a-Si film 5a with a pulse laser 4, The a-Si film 5a is crystallized to form a thin p-Si (polysilicon) film 5b.

  The stage 10 irradiates the pulse laser 4 while moving along the forward path or the backward path consisting of the scan axis x in the X-axis direction, and then the stage 10 is scanned by the scan interval y in the Y-axis direction orthogonal to the scan axis x. A reciprocating scanning method is performed in which the object 5 is irradiated with the pulse laser 4 over the entire width of the return path or the forward path. By continuation of this operation, the entire surface (irradiation range) of the irradiation object 5 is irradiated with the pulsed laser 4, and the irradiation object 5 whose entire surface has reached the predetermined number of irradiations (1 to 20 times) is exchanged. The pulsed laser 4 is irradiated on the object 5 to be irradiated. Accordingly, the X-axis direction coincides with the direction of the horizontal scan axis x passing through the irradiation site of the pulse laser 4 consisting of a series of shots, and the scan axis x which is the width of the pulse laser 4 in the Y-axis direction. Has a scan interval y, which is the amount of displacement of the pulse laser 4 in the Y-axis direction, or larger, and the pulse lasers 4 overlap each other in the Y-axis direction.

  Specifically, the moving device 20 has an X-axis servo 55 shown in FIG. In other words, the servo motor 40 is provided, and the stage 10 is moved in the X-axis direction intermittently or continuously at predetermined intervals via a ball screw mechanism (not shown) by forward and reverse rotation of the servo motor 40.

  The servo motor 40 of the moving device 20 is driven by the servo control device 60 based on the driving signal R4 shown in FIG. 3, and stops when the moving signal Zn is subtracted from the driving signal R4 to become zero, The stage 10 and the irradiated object 5 are also stopped. Thereafter, the stage 10 is intermittently moved to one side in the Y-axis direction at a scan interval y by a Y-axis servo (not shown).

  Subsequently, the servo motor 40 is driven in reverse rotation, and when the movement signal Zn is subtracted from the drive signal R4 and becomes zero, the servo motor 40 stops again, and the stage 10 and the irradiated object 5 that move in the backward direction also stop. Thereafter, the stage 10 is intermittently moved to one side in the Y-axis direction at a scan interval y by a Y-axis servo (not shown).

  By repeating this, the irradiated object 5 on the stage 10 reciprocates relative to the pulse laser 4 from the laser oscillation device 1 in the X-axis direction.

  The movement signal Zn detects the number of rotations (rotation angle) of the servo motor 40 by the rotary encoder 41, the detection pulse is counted by the first counter 42, and the movement length of the stage 10 becomes a predetermined value. It is obtained as a pulse signal every time. Therefore, the movement signal Zn corresponds to a predetermined movement length of the stage 10 for each pulse.

  The specific speed of the stage 10 that moves from left to right in FIG. 4 (a) by the X-axis servo 55 is about 100 to 800 mm / sec. The pulsed laser 4 irradiated intermittently emits, for example, 50 to 1,000 times per second, and the time during which one shot is emitted is about 2 nsec to 10 μsec. Thus, since the time during which the pulse laser 4 emits light is very short compared to the moving speed of the stage 10, the X-axis servo 55 is provided in the X-axis direction even when the stage 10 is continuously moved. Depending on the value of the first counter 42 indicating the position, the pulse laser 4 can be irradiated at equal intervals. That is, the drive of the stage 10 by the servo motor 40 can irradiate practically without any problem even if intermittent irradiation is performed by stopping and irradiating at a place where irradiation is performed one by one.

  This movement signal Zn is counted by the second counter 43 and outputs a signal I for oscillating the pulse laser 4 every time the stage 10 moves at a predetermined interval every time the count value 1 / N1 is reached. The laser I is driven by this signal I, and the pulse laser 4 is irradiated. Accordingly, the pulse laser 4 is irradiated one after another on the object 5 on the stage 10 at a predetermined distance and position.

  And as shown in FIG. 1, the raising / lowering drive apparatus 30, the distance sensor 31, the basic control value setting means 32, the 1st calculating means 33, the delay means 34, the memory | storage means 35, and the 2nd calculating means 36 are provided.

  The raising / lowering drive device 30 has a function of moving the stage 10 up and down relatively with respect to the laser oscillation device 1, the reticle 21 and the objective lens 3, and is driven by a servo motor 53 that is rotated in the forward and reverse directions shown in FIG. The first inclined block 38 is driven forward and backward in the horizontal direction via the ball screw mechanism 37. As a result, the second inclined block 39 engaged with the first inclined block 38 on the inclined surface moves up and down, so that the stage 10 integrated with the second inclined block 39 moves up and down in the Z-axis direction. The first inclined block 38 is supported slidably in the horizontal direction on the base 22 side, and the stage 10 is supported slidable in the vertical direction on the base 22 side.

  The distance sensor 31 is positioned in a direction perpendicular to the scan axis x in plan view with respect to the irradiation position of the pulse laser 4 to the irradiation object 5, and is placed on the stage 10 of the pulse laser 4 as shown in FIG. The pulse laser 4 of the irradiated object 5 is provided on the laser oscillation device 1 side, which is the base 22 side, with a predetermined distance L from the irradiation position of the irradiated object 5 to the rear side in the traveling direction of the stage 10. The distance h in the Z-axis direction from the irradiation surface is measured. The predetermined distance L is a distance that the stage 10 is moved by the moving device 20, and specifically, is a distance corresponding to the length of two scan axes x and two scan intervals y as shown in FIG. If the predetermined distance L is accurately matched with an integral multiple of the moving distance of the stage 10 that is advanced by light emission (one shot) of the pulse laser 4, the pulse laser 4 can be irradiated to the measurement position by the distance sensor 31. However, it is not essential to match the integer multiple exactly. Further, the distance in the Y-axis direction between the distance sensor 31 and the irradiation position of the pulse laser 4 on the object 5 to be irradiated is accurately matched with an integral multiple of the interval of the scan axis x (scan interval y) in plan view. Then, it becomes possible to irradiate the measurement position by the distance sensor 31 with the pulsed laser 4, but it is not essential to accurately match the integral multiple.

  The distance h measured by the distance sensor 31 is positioned in parallel with the optical axis of the pulsed laser 4 irradiated to the irradiated object 5 after passing through the reticle 21 and the objective lens 3. The distance sensor 31 sequentially measures the distance h between the irradiation object 5 and the irradiation surface of the pulse laser 4 at predetermined intervals, and outputs the detection values hn one after another. Thus, the distance sensor 31 is provided on the laser oscillation device 1 side, and the scan axis line x is changed from the irradiation position of the pulse laser 4 on the scan axis line x of the irradiated object 5 to the rear side in the traveling direction of the stage 10. The distance h from the irradiation surface of the pulse laser 4 of the irradiated object 5 at a position separated from the irradiation position of the pulse laser 4 by a distance corresponding to the predetermined distance L by the moving device 20 is measured one after another. The detection value hn is output.

  The basic control value setting means 32, the delay means 34, the first calculation means 33, the storage means 35, and the second calculation means 36 are configured by a microcomputer. The basic control value setting means 32 corresponds to an appropriate distance between the irradiation object 5 placed on the stage 10 having a uniform thickness and the objective lens 3 when the surface of the irradiation object 5 is flat without unevenness. The basic control value H to be output is output. That is, the basic control value H is a position setting value in the initial state of the irradiation object 5 placed on the stage 10 when the reticle 21 is correctly imaged on the irradiation object 5, and is changed once set. There is no need. The appropriate distance between the irradiation surface of the pulse laser 4 of the irradiation object 5 and the objective lens 3 corresponds to the appropriate distance h measured by the distance sensor 31.

  The delay means 34 outputs the detection value hn of the distance sensor 31 by delaying the predetermined distance L according to a predetermined time required for the stage 10 to move, and when the stage 10 has moved the predetermined distance L. The distance h from the irradiation surface of the object 5 to be irradiated with the pulse laser 4 is made appropriate. However, the delay means 34 may be provided so that a control difference value δ, which will be described later, is finally delayed by a predetermined time and output to the elevating drive device 30. Therefore, the delay means 34 can be disposed between the second calculation means 36 and the elevating drive device 30.

  The first calculation means 33 obtains a difference value Δn between the basic control value H set by the basic control value setting means 32 and the detected value hn of the distance sensor 31 by H−hn = Δn, and the difference value Δn is output.

  The storage means 35 successively stores the difference value Δn−1 obtained last time among the difference values Δn output one after another from the first calculation means 33. The second calculation means 36 obtains a control difference value δ, which is the difference between the difference value Δn−1 obtained before being stored in the storage means 35 and the difference value Δn obtained next, by Δn− (Δn−1). = Δ is calculated.

  Then, the raising / lowering driving device 30 is driven in accordance with the control difference value δ, and the pulse laser 4 of the irradiation object 5 placed on the stage 10 while maintaining the distance between the reticle 21 and the objective lens 3 constant. And the distance h between the objective lens 3 and the irradiation surface of the pulse laser 4 of the irradiation object 5 placed on the stage 10 is controlled appropriately.

  A specific configuration of the irradiation distance automatic adjusting device will be described with reference to FIG. The automatic irradiation distance adjustment device includes a signal processing unit 57 using a first FIFO (First In First Out) memory 45 and a second FIFO memory 46, a Z-axis servo 56 that drives the stage 10 in the vertical direction, and a distance sensor 31. Have The FIFO memories 45 and 46 are also called field image memories. When storing, retrieving, and using data, the FIFO memories 45 and 46 are memories that can be retrieved from the previous data in the order of storage.

  In the signal processing unit 57 using the FIFO memories 45 and 46, the movement signal Zn is previously counted by the third counter 44, and the pulse signal J is output every time the count value 1 / N2 is reached. Is output, the signal processing unit 57 operates and performs calculations using the FIFO memories 45 and 46. Therefore, the pulse signal J is generated based on the drive signal R4.

  Here, if the stage 10 is moved in the X-axis direction by the moving device 20, a pulse of the movement signal Zn is generated, and the movement distance of the stage 10 per one pulse (P) is 0.01 to 10 μm / It is about P. For example, the description is continued when the movement signal Zn is 1 μm / P. The second counter 43 counts the pulses of the movement signal Zn and outputs one pulse signal I to the laser oscillation device 1 every N1 counts to cause the pulse laser 4 to emit light. As a specific example, N1 is 1,000 and the pulse laser 4 is irradiated every 1 mm. On the other hand, the third counter 44 outputs a pulse signal J every N2 counts, and when the pulse signal J is output, the signal processing unit 57 performs calculations.

  In general, the number of stages of the first FIFO memory 45 (n stages in the first FIFO memory 45 in FIG. 3) is M, and the distance sensor 31 of each distance sensor 31 is determined from the distance Lmm (2x + y) in FIG. If the detection value hn is extracted from the first FIFO memory 45 and calculated, the detection value hn of the distance sensor 31 can be calculated by delaying the predetermined distance L according to the time required for the stage 10 to move. it can. Therefore, if the value of the count number N2 of the third counter 44 is set to L / M / 1 μm, the lifting drive device 30 can be driven in accordance with the movement of the stage 10. If the value of N2 is made equal to the value of N1, the elevation drive device 30 can be driven based on the detection value hn of the distance sensor 31 in accordance with the light emission of the pulse laser 4. However, it is not essential to drive the elevating drive device 30 in accordance with the light emission (one shot) of the pulse laser 4.

  In the first FIFO memory 45, the detection value hn of the distance sensor 31 is inputted every predetermined time (every N2 count), and this is sequentially moved to M1, M2, M3. The output is outputted from Mn with a delay according to a predetermined time. Accordingly, the first FIFO memory 45 functions as a delay means 34 that outputs the detection value hn of the distance sensor 31 with a delay in accordance with the time required for the stage 10 to move the predetermined distance L. However, since the detection value hn of the distance sensor 31 is changed to the control difference value δ later, the control difference value δ is output after being delayed according to the time required for the stage 10 to move the predetermined distance L. The action is the same.

  The detection value hn extracted from the first FIFO memory 45 reaches the first calculation means 33 shown in FIG. 3, and the difference value Δn between the basic control value H output from the basic control value setting means 32 and the detection value hn. Are successively obtained as H−hn = Δn.

  The second FIFO memory 46 stores and stores the difference value Δn output from the first calculation means 33 one after another. When the next pulse signal J is output, a difference value Δn between the detection value hn of the distance sensor 31 output this time and the basic control value H is obtained from the first FIFO memory 45, and this difference value Δn Is stored / stored in the second FIFO memory 46, bypasses the second FIFO memory 46, and reaches the second computing means 36 shown in FIG.

  In the second calculation means 36, the control difference value δ, which is the difference between the previous difference value Δn−1 taken out from the second FIFO memory 46 and the current difference value Δn, is Δn− (Δn−1) = δ. As one after another. Therefore, the second FIFO memory 46 functions as the storage means 35 that stores the previously obtained difference value Δn−1.

  The control difference value δ is input to the Z-axis servo 56. The Z-axis servo 56 includes a servo motor 53, and rotates the servo motor 53 forward or backward to move the stage 10 up and down via the ball screw mechanism 37 shown in FIG.

  The servo motor 53 of the Z-axis servo 56 is driven while being controlled by the servo controller 61 on the basis of the control difference value δ shown in FIG. 3, and subtracts the lifting / lowering movement signal Zn2 from the control difference value δ serving as a drive signal. Then, when it reaches zero, the stage 10 and the irradiated object 5 are also stopped. The up / down movement signal Zn2 is detected by the rotary encoder 51 by detecting the number of rotations (rotation angle) of the servo motor 53, the detected pulses are counted by the fourth counter 52, and the up / down movement length of the stage 10 is predetermined. Every time it becomes a value, it is obtained as a pulse signal. Therefore, the up / down movement signal Zn2 corresponds to a predetermined up / down movement length of the stage 10 for each pulse.

Next, the operation of the first embodiment will be described.
Initially, a basic control value H is set in the basic control value setting means 32, and the distance between the object 5 placed on the stage 10 and the objective lens 3 is a large number of objects having the same basic thickness. 5 is in an appropriate state. Accordingly, the height position of the distance sensor 31 is in an appropriate distance h, and the distance h of the left end portion of the irradiation object 5 in FIG. 4 (a), that is, the forward irradiation start position B1 in FIG. Start measurement. At this time, the pulse laser 4 is at the processing start position D that is out of the irradiation object 5. That is, when the distance sensor 31 is in the left end portion of one scan axis x3 that is the first irradiation position of the pulse laser 4 to the irradiated object 5 in the plan view, that is, at the forward irradiation start position B1, the pulse laser 4 Is separated from the scan axis x3 by a predetermined distance L required for movement on the scan axis x1 obtained by making the two scan axes different from the back in the direction of travel of the stage 10.

  After the measurement of the distance h of one scan axis x3 is completed, the stage 10 is displaced by one scan interval y1 to one side in the Y-axis direction by the Y-axis servo (not shown), and similarly the return irradiation start position The distance h is measured one after another from the right end of the next scan axis x4 including B2. When the distance h to the left end of the scan axis x4 has been measured, the next scan including the forward irradiation start position B3 is similarly performed by displacing the scan axis y1 by the same scan interval y3 as the one scan interval y1. The measurement of the distance h is started from the left end portion of the axis x5.

  Simultaneously with the displacement of the scan interval y2 of the pulse laser 4, the pulse laser 4 reaches the forward irradiation start position B1, so that irradiation of the irradiation object 5 with the pulse laser 4 is continued thereafter. When the irradiation of the pulse laser 4 a predetermined number of times onto the last scan axis line xn on the irradiation object 5 is completed, the processing on the irradiation object 5 is completed.

  That is, based on the drive signal R4, the moving device 20 is driven by the servo control device 60 as described above, and the irradiated object 5 placed on the stage 10 moves left and right on FIG. The distance 31 between the irradiated object 5 and the irradiation surface of the pulse laser 4 is measured one after another at a predetermined interval by the sensor 31, the laser oscillation device 1 is driven by the signal I, and the pulse laser 4 is irradiated. . Since the distance sensor 31 starts measurement from the distance h of the forward irradiation start position B1 of the irradiation object 5, the pulse laser 4 is distanced from one scan axis x3 that is the first irradiation position to the irradiation object 5. Irradiation starts from a position separated by L, that is, a processing start position D on the scan axis x1.

  On the other hand, the distance h between the irradiation object 5 and the irradiation surface of the pulse laser 4 is successively measured by the distance sensor 31 at predetermined intervals, and the detection value hn is successively staged through the delay means 34 to the predetermined distance L. 10 is output after being delayed by the time required for movement, and is input to the first calculation means 33, and the basic control value H from the basic control value setting means 32 is input to the first calculation means 33. The first calculating means 33 obtains a difference value Δn between the basic control value H and the detected value hn one after another every time the detected value hn is generated.

  This difference value Δn is stored one after another in the storage means 35 and also enters the second calculation means 36, and the second calculation means 36 obtains the difference value Δn−1 obtained before being obtained from the storage means 35 and its difference value Δn−1. Next, a control difference value δ (Δn− (Δn−1) = δ) consisting of a difference from the obtained difference value Δn is calculated one after another.

  Then, on the basis of the control difference value δ obtained one after another, after the irradiation position of the pulse laser 4 passes the forward irradiation start position B1, the elevating drive device 30 is driven one after another, and the laser oscillation device 1, reticle 21 and The stage 10 is moved up and down relatively with respect to the objective lens 3, and the pulse laser 4 is irradiated while making the height of the irradiation range of the irradiation object 5 on the stage 10 appropriate.

  For example, when the irradiation surface of the irradiation object 5 forms a recess and the difference value Δn is a negative value, the stage 10 is moved up and down relative to the reticle 21 and the objective lens 3 by the elevating drive device 30. Then, the height position of the irradiated surface of the irradiated object 5 at the time of irradiation with the pulse laser 4 is matched with the appropriate height based on the basic control value H. On the other hand, when the irradiated surface of the irradiation object 5 forms a convex portion and the difference value Δn is a positive value, the stage 10 is lowered relative to the reticle 21 and the objective lens 3 by the lifting drive device 30. The height position of the irradiated surface of the irradiation object 5 at the time of irradiation with the pulse laser 4 is matched with the appropriate height based on the basic control value H. Thus, the pulse laser 4 continues to be irradiated while the height position of the irradiation surface of the irradiation object 5 is appropriate with respect to the reticle 21 and the objective lens 3. Of course, the moving device 20 does not hinder the lifting / lowering operation of the stage 10.

  In this way, the adjustment of the height of the irradiation range of the irradiation object 5 is started after passing the forward irradiation start position B1, and the pulse laser 4 is moved onto the last scan axis line xn on the irradiation object 5. This is continued until the irradiation is completed. As a result, the irradiation of the pulse laser 4 is started simultaneously with the start of the measurement of the height of the irradiation range of the irradiation object 5 and the irradiation of all the pulse lasers 4 in the irradiation range of the irradiation object 5 is completed. Thus, the useless range in which the irradiation of the pulse laser 4 deviates from the irradiation range of the irradiation object 5 can be limited to the irradiation on the two scan axes x1 and x2. Thus, the wasteful range in which the irradiation of the pulse laser 4 deviates from the irradiation range of the irradiated object 5 is only one side of the irradiated object 5 (upper side in FIG. 5), thereby narrowing the irradiated object. It is possible to enable efficient processing of the object 5 in a short time.

  Next, the case where the detection value hn of the distance sensor 31 is input to the FIFO memory 45 shown in FIG. 3 will be described. At this time, the distance h between the irradiation object 5 and the irradiation surface of the pulse laser 4 is measured by the distance sensor 31, and when the pulse signal J is output, the detection values hn are successively obtained from the signal processing unit 57. While being input to the first FIFO memory 45, calculation using the FIFO memories 45 and 46 is performed. That is, while the detection value hn is sequentially input to the first FIFO memory 45 that is the delay means 33, the stage 10 and the irradiated object 5 move, and the first FIFO memory is simultaneously input with the input of the (n + 1) th detection value hn. 45, the detection value hn input for the first time is output. The delayed detection value hn reaches the calculating means 33, the basic control value H of the basic control value setting means 32 is obtained, and the difference value Δn is calculated. This difference value Δn is stored in the second FIFO memory 46 which is the storage means 35.

  Subsequently, when the next pulse signal J is output, the next detection value hn is output from the first FIFO memory 45, and the difference value Δn stored in the second FIFO memory 46 is previously obtained. The second calculation means 36 enters the second calculation means 36 as a difference value Δn−1, and the second calculation means 36 controls the difference between the previous difference value Δn−1 obtained from the second FIFO memory 46 and the current difference value Δn. The difference value δ (Δn− (Δn−1) = δ) is calculated.

  Based on this control difference value δ, the elevation drive device 30 is driven, and the stage 10 is moved up and down relative to the laser oscillation device 1, the reticle 21 and the objective lens 3, and the irradiation object 5 on the stage 10 is moved. The pulse laser 4 is irradiated while appropriately controlling the height of the irradiated portion (after passing the forward irradiation start position B1).

  Thereby, the distance from the objective lens 3 to the irradiated object 5 is adjusted / corrected by relatively changing the position of the irradiated object 5 while keeping the distance between the reticle 21 and the objective lens 3 constant. Thus, the image of the reticle 21 can be faithfully formed on the irradiated object 5 by the objective lens 3. In addition, the distance sensor 31 is arranged away from the optical axis of the reticle 21 and the objective lens 3 so that the distance from the objective lens 3 on the optical axis to the imaging surface (irradiation surface) of the irradiated object 5 is always controlled to be constant. can do.

  By the way, in the first embodiment, the stage 10 is moved by the moving device 20 in the horizontal X-axis direction and the Y-axis direction with respect to the pulse laser 4 from the laser oscillation device 1. It is also possible to move the laser oscillation device 1, the optical device 9, the reticle 21 and the objective lens 3 together in the direction opposite to the X axis direction and the Y axis direction. Further, instead of moving the stage 10 up and down with respect to the laser oscillation device 1, the optical device 9, the reticle 21, and the objective lens 3 by the elevation drive device 30, the laser oscillation device 1, the optical device 9, the reticle 21, and the objective are moved. It is also possible to move the lens 3 up and down as a unit.

The figure which shows the component of the irradiation distance automatic adjustment apparatus which concerns on 1 embodiment of this invention. The side view which similarly shows the principal part. The figure which similarly shows the structure for obtaining in connection with the drive of the X-axis servo which moves a stage, the Z-axis servo which operates an irradiation distance automatic adjustment apparatus, and a laser oscillation apparatus. The state which irradiates the irradiation object on a stage similarly with the pulse laser from a laser oscillation apparatus is shown, (A) is a front view, (B) is a right view. The top view for action explanation similarly. The front view which shows the apparatus which measures the distance on the optical axis of the conventional objective lens and to-be-irradiated object. FIG. FIG.

Explanation of symbols

1: Laser oscillation device 3: Objective lens 4: Pulse laser 5: Irradiated object 10: Stage 20: Moving device 21: Reticle 30: Lifting drive device 31: Distance sensor 32: Basic control value setting means 33: First calculation Means 34: Delay means 35: Storage means 36: Second computing means 45: First FIFO memory 46: Second FIFO memory H: Basic control value h: Distance hn: Detection value L: Predetermined distance δ: Control difference value Δn: difference value Δn-1: previously obtained difference value x: scan axis y: scan interval

Claims (4)

The laser oscillation device (1), the stage (10) on which the object (5) is placed, and the stage (10) are moved relative to the laser oscillation device (1) in the X-axis direction and the Y-axis direction. A device (20),
While continuously moving the stage (10) in the X-axis direction and then displacing it in the Y-axis direction according to the scan interval (y) and moving the return path in the X-axis direction, the reticle (21) And an object to be irradiated (5) on which a pulse laser (4) from the laser oscillation device (1) which is sequentially passed through the objective lens (3) and focused by the objective lens (3) is placed on the stage (10). In the irradiation distance automatic adjustment method of irradiating the scan axis line (x) at predetermined intervals,
An elevating drive device (30) for moving the stage (10) up and down relatively with respect to the laser oscillation device (1), the reticle (21) and the objective lens (3);
Provided on the laser oscillation device (1) side, the scan axis line from the irradiation position of the pulse laser (4) onto the scan axis (x) of the irradiated object (5) to the rear side in the traveling direction of the stage (10) The pulse of the object to be irradiated (5) at a position separated from the irradiation position of the pulsed laser (4) by a distance corresponding to a predetermined distance (L) by the moving device (20) with different (x). A single distance sensor (31) for measuring the distance (h) to the irradiation surface of the laser (4) one after another and outputting a detection value (hn);
A basic control value setting means (32) for outputting a basic control value (H) corresponding to an appropriate distance between the object to be irradiated (5) placed on the stage (10) and the objective lens (3); ,
The difference value (Δn) between the basic control value (H) and the detected value (hn) is obtained one after another, and the difference between the previously obtained difference value (Δn−1) and the next obtained difference value (Δn). A control difference value (δ) comprising: the control difference value (δ) is output with a delay in accordance with the time required for the stage (10) to move the predetermined distance (L),
By driving the lifting / lowering drive device (30) according to the control difference value (δ), the objective lens (3) and the stage (3) are maintained while keeping the distance between the reticle (21) and the objective lens (3) constant. 10. A method for automatically adjusting an irradiation distance, comprising controlling the distance of the irradiated object (5) placed on 10) to the irradiation surface of the pulse laser (4). The laser oscillation device (1), the stage (10) on which the object (5) is placed, and the stage (10) are moved relative to the laser oscillation device (1) in the X-axis direction and the Y-axis direction. And an apparatus (20) for continuously moving the stage (10) in the X-axis direction and then moving the return path in the X-axis direction by displacing the stage (10) in the Y-axis direction according to the scan interval (y). The pulse laser (4) from the laser oscillation device (1) focused by the objective lens (3) through the reticle (21) and the objective lens (3) in sequence is applied to the stage (10). In the irradiation distance automatic adjustment device that irradiates the scanning object (5) on the scanning axis (x) at predetermined intervals,
An elevating drive device (30) for moving the stage (10) up and down relatively with respect to the laser oscillation device (1), the reticle (21) and the objective lens (3);
Provided on the laser oscillation device (1) side, the scan axis line from the irradiation position of the pulse laser (4) onto the scan axis (x) of the irradiated object (5) to the rear side in the traveling direction of the stage (10) The pulse of the object to be irradiated (5) at a position separated from the irradiation position of the pulsed laser (4) by a distance corresponding to a predetermined distance (L) by the moving device (20) with different (x). A single distance sensor (31) for measuring the distance (h) to the irradiation surface of the laser (4) one after another and outputting a detection value (hn);
A basic control value setting means (32) for outputting a basic control value (H) corresponding to an appropriate distance between the irradiated object (5) placed on the stage (10) and the objective lens (3);
First calculating means (33) for successively obtaining a difference value (Δn) between the basic control value (H) and the detected value (hn);
Storage means (35) for storing the previously obtained difference value (Δn−1);
Second calculating means (36) for obtaining a control difference value (δ) comprising a difference between a previously obtained difference value (Δn−1) and a difference value (Δn) obtained next;
Delay means (34) for delaying and outputting the control difference value (δ) according to the time required for the stage (10) to move the predetermined distance (L);
The lifting / lowering driving device (30) is driven according to the control difference value (δ), and the objective lens (3) and the stage (10) are maintained while maintaining a constant distance between the reticle (21) and the objective lens (3). The irradiation distance automatic adjustment apparatus characterized by controlling the distance of the to-be-irradiated object (5) mounted on the irradiation surface of the pulse laser (4). The delay means (34) is constituted by the first FIFO memory (45), and delays the detection value (hn) according to the time required for the stage (10) to move the predetermined distance (L). 3. The irradiation distance automatic adjusting device according to claim 2, wherein the output of the control difference value (δ) is delayed. 4. The automatic irradiation distance adjusting device according to claim 2, wherein the storage means (35) is constituted by a second FIFO memory (46).

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