KR100498831B1 - A method and an apparatus for automatically adjusting irradiation distance - Google Patents

Abstract

(Problem) Since both the laser light for crystallization and the light for distance measurement are guided on the same optical axis, not only are the interferences of both lights easily generated, but also the reflected light or the transmitted light is generated when passing through the half mirror, resulting in a decrease in intensity.

(Solution means) A lifting and lowering drive device 30 which relatively moves the stage 10 relative to the reticle 21 and the objective lens 3, and a predetermined distance L from the pulse laser 4, are provided. 5) Measure the distance h with the irradiation surface in order one by one, and the basic control value H corresponding to the appropriate distance between the irradiated object 5 and the objective lens 3 and outputting the detection value hn. A basic control value setting means (32) to be outputted, wherein the difference value (Δn) between the basic control value (H) and the detected value (hn) is sequentially obtained, and the difference is obtained by the difference between the difference value (Δn-1) obtained last time and the difference value (Δn) obtained this time. The control difference value δ is obtained, and the control difference value δ is delayed and output by the time required to move the predetermined distance L, and the lift drive device 30 is driven in accordance with the control difference value δ to control the distance.

Description

A METHOD AND AN APPARATUS FOR AUTOMATICALLY ADJUSTING IRRADIATION DISTANCE}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method for automatically adjusting the irradiation distance and a device thereof, and more particularly, to a method and an apparatus for automatically adjusting the irradiation distance between an objective lens for focusing pulses and lasers from a laser oscillation device and an irradiated object mounted on a stage. will be.

Conventionally, in the production of crystallized silicon of thin film transistors, a laser beam is irradiated to an irradiated object on which a thin a-Si (amorphous silicon) film is formed on a glass substrate to crystallize the a-Si film to form a thin p-Si (polysilicon) film. I am doing it. As a method of irradiating a laser beam to this a-Si film, a laser beam of uniform intensity is shot on a reticle (mask), which is imaged by projecting onto an s-Si film of an irradiated object with an objective lens of an optical device. There is a method (for example, Japanese Patent No. 3204986).

This is a rectangular line by guiding a laser beam generated by a laser oscillation device that generates an excimer laser to an optical device, directionally changing by a reflecting mirror, shaping and equalizing the intensity, and passing the reticle and the objective lens. It is shaped by a beam (pulse laser) and irradiated to the irradiated object to be transferred. The irradiated object is installed in the vacuum chamber of the laser annealing apparatus.

In such a case, there are three methods of classifying the image of the reticle faithfully into the irradiated object by the objective lens.

Firstly, the distance between the reticle and the objective lens is appropriately formed by changing the position of the reticle to form an object. Secondly, by changing the position of the objective lens, the distance between the reticle and the objective lens is appropriately formed to form an irradiated object. Third, the distance between the reticle and the objective lens is kept constant, and the distance from the objective lens to the irradiated object is appropriately formed by changing the position of the irradiated object to form an image on the irradiated object.

The first and second have the drawback that the size of the image to be imaged is changed. Therefore, the present invention adopts the third method. Here, if the precision of the stage and the shape value of the irradiated object are good, no problem occurs, but in terms of the stage itself, in reality, when the vertical movement (Z axis) is stopped and moved only in the horizontal direction (X), the maximum is 10. The micrometer changes. In addition, the thickness of an irradiated object changes about 30 micrometers at maximum. That is, the change about 40 micrometers in total arises. For this reason, it is necessary to keep the stage up and down to keep the distance from the objective lens to the imaging surface of the irradiated object constant.

However, in order to obtain an appropriate image formation on the entire surface of the irradiated object, it is necessary to measure and control the distance between the objective lens and the optical axis of the irradiated object. There are several conventional ways to accomplish this.

The representative example is shown in FIG. This causes the pulse laser generated by the laser oscillator to pass through the reticle 70, and is appropriately redirected by the reflection mirror 72 made up of the reflection mirror 71 and the half mirror to turn the objective lens 73. After passing through, the surface of the irradiated object 74 is irradiated.

On the other hand, the distance on the optical axis of the objective lens 73 and the to-be-projected object 74 is measured by suitable light. That is, after passing the light 81 through the cylindrical lens 76, it is reflected by the reflection mirror 77 made of a half mirror, while passing through the reflection mirror 72 to pass through the objective lens 73 to focus, The surface of the irradiated object 74 is irradiated and the reflected light is passed through the objective lens 73 and the reflection mirrors 72 and 77 to be received by the measuring instrument 78.

Then, it is determined whether or not the distance between the objective lens 73 and the irradiated object 74 on the optical axis is appropriate from the shape of the light 81 received by the measuring device 78, and the lifting drive device (not shown) so as to be in an appropriate state. The stage 79 and the irradiated object 74 are moved up and down by this. The distance error (B-A) on the optical axis of the objective lens 73 and the irradiated object 74 is preferably within 5 μm. The shape of the light 81 received by the measuring device 78 is as shown in FIG. 6, and FIG. 6 (a) shows that the objective lens 73 is close to the irradiated object 74. 6C shows that the objective lens 73 is far from the irradiated object 74.

However, in the case of irradiating a laser beam for the production of crystallized silicon of the thin film transistor, a laser beam 80 having a very strong intensity is required, and the strength decreases due to reflection in the reflection mirror 72 or the like made of a half mirror. In addition, when the distance measuring light 81 passes through the reflecting mirrors 72 and 77 made of the half mirror, not only the reflected light or the transmitted light is generated, but also the intensity decreases, and the distance measuring light 81 In the case where the wavelength such as ultraviolet rays is short, interference with the laser light 80 is likely to occur, and thus there is a side that is difficult to adopt. In addition, even when the half mirror which passes the light 81 of a predetermined wavelength is used as the reflection mirrors 72 and 77, since the reflection mirror 77 reflects and transmits the light 81 of the same wavelength, it is transmitted light or reflected light. Induces the decrease in strength. In addition, since the laser light 80 and the light 81 have different wavelengths, it is difficult to determine whether or not the distance is correctly formed by shifting the image forming position after passing through the objective lens 73. This is attributable to guiding both the crystallization laser light 80 and the distance measuring light 81 on the same optical axis.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic irradiation distance adjusting method and a device in which a distance meter is provided at a position away from the optical axis of a pulse laser when irradiating a laser while moving the irradiated object relative to each other. I am doing it.

This invention is made | formed in view of such a conventional technical subject, and its structure is as follows.

The invention of claim 1 is a movement for relatively moving the laser oscillation apparatus 1, the stage 10 on which the irradiated object 5 is mounted, and the stage 10 relative to the laser oscillation apparatus 1 in a predetermined direction X. The stage 20 includes a pulse laser from the laser oscillation apparatus 1 having an apparatus 20 and focused through the reticle 21 and the objective lens 3 sequentially and focused by the objective lens 3. In the irradiation distance automatic adjustment method to irradiate the irradiation target (5) mounted on the

A lift driving device 30 for lifting and lowering the stage 10 relative to the laser oscillation device 1, the reticle 21 and the objective lens 3,

It is provided on the side of the laser oscillation apparatus 1 with the predetermined distance L behind the advancing direction of the stage 10 from the irradiation position of the pulse laser 4 to the said to-be-projected object 5, The said to-be-projected object 5 The distance meter 31 which measures the distance h from the irradiation surface of the pulse-laser 4 of the laser beam 4 sequentially and outputs the detection value hn, the irradiated object 5 mounted on the stage 10 and the objective lens. (3) has a basic control value setting means 32 for outputting a basic control value H corresponding to an appropriate distance therebetween,

The control difference value which consists of the difference of the difference value (DELTA) n-1 calculated | required previously, and the difference value (DELTA) n calculated | required next, while obtaining the difference value (DELTA) n between the basic control value (H) and the detected value (hn) in order. (delta) is calculated | required, and this control difference value (delta) is made to delay and output the said predetermined distance L by the time required for the stage 10 to move,

By driving the elevating drive device 30 in accordance with the control difference value δ, the target mounted on the objective lens 3 and the stage 10 while keeping the distance between the reticle 21 and the objective lens 3 constant. A method of automatically adjusting the irradiation distance, characterized by controlling the distance of the irradiation surface of the pulse laser (4) of the object (5).

The invention according to claim 2 is a movement for relatively moving the laser oscillation apparatus 1, the stage 10 on which the irradiated object 5 is mounted, and the stage 10 relative to the laser oscillation apparatus 1 in a predetermined direction X. The stage 20 includes a pulse laser from the laser oscillation apparatus 1 having an apparatus 20 and focused through the reticle 21 and the objective lens 3 sequentially and focused by the objective lens 3. In the irradiation distance automatic control device for irradiating the irradiated object (5) mounted on the at every predetermined interval,

A lift driving device 30 for lifting and lowering the stage 10 relative to the laser oscillation device 1, the reticle 21 and the objective lens 3,

It is provided on the side of the laser oscillation apparatus 1 with the predetermined distance L behind the advancing direction of the stage 10 from the irradiation position of the pulse laser 4 to the said to-be-projected object 5, The said to-be-projected object 5 The distance meter 31 which measures the distance (h) from the irradiation surface of the pulse laser (4) one by one, and outputs the detection value (hn),

Basic control value setting means (32) for outputting a basic control value (H) corresponding to the distance between the irradiated object (5) mounted on the stage (10) and the objective lens (3);

First calculating means 33 which sequentially obtains the difference value Δn between the basic control value H and the detected value hn;

Storage means 35 for storing the previously obtained difference value? N-1;

Second calculating means 36 for obtaining a control difference value δ consisting of a difference between the previously obtained difference value? N-1 and the next difference value? N;

Has a delay means 34 for delaying and outputting this control difference value δ by the time required for the stage 10 to move, and outputting the predetermined distance L,

The lift drive device 30 is driven in accordance with the control difference value δ so as to be mounted on the objective lens 3 and the stage 10 while keeping the distance between the reticle 21 and the objective lens 3 constant. An irradiation distance automatic control device characterized in that the distance of the irradiation surface of the pulse laser (4) of the irradiated object (5) is controlled.

According to the invention of claim 3, the delay means 34 is constituted by the first FIFO memory 45, and the detection value hn is delayed by the time required for the stage 10 to move the predetermined distance L. And outputting the delayed output of the control difference value δ.

The invention according to claim 4 is the irradiation distance automatic adjustment device according to claim 2 or 3, wherein the storage means 35 is constituted by the second FIFO memory 46.

Embodiment of the invention

1 to 4 show one embodiment of the automatic irradiation distance adjusting device according to the present invention. In the drawing, reference numeral 10 is a stage, and as shown in FIG. 3, the stage 10 is moved by the moving device 20 to the laser oscillation apparatus 1 in a state where the projected object 5 made of a substrate is mounted on the stage 10. Relative to the pulse laser 4 from the laser beam 4). In addition, the stage 10 is actually reciprocated in the predetermined direction X. FIG.

 As shown in Fig. 4A, the laser oscillation apparatus 1 is fixed to the base 22 to generate an excimer laser made of a pulse laser, and the generated laser light A1 is reticle 21 and Guided to the optical device 9 including the objective lens 3, the direction is changed to the reflecting mirror 7, and passed through the long axis homogenizer 2a and the single axis homogenizer 2b to form a uniform strength. Afterwards, the object is irradiated to the reflective mirror 8 again and passed through the reticle 21 and the objective lens 3 to form a pulse laser 4 made of a rectangular line beam, and to be mounted on the stage 10. (5) is irradiated so that it may project and image. The reticle 21 and the objective lens 3 are arranged to coincide with the optical axes and fixed at predetermined intervals, and the optical axes are orthogonal to the irradiation surface of the irradiated object 5. The irradiated object 5 is provided in a vacuum chamber of the laser annealing apparatus.

The irradiated object 5 formed the thin a-Si (amorphous silicon) film | membrane 5a on the glass substrate 6 as shown in FIG. 4, The pulse-laser 4 was formed in this a-Si film | membrane 5a. The a-Si film 5a is crystallized by irradiating to give a thin p-Si (polysilicon) film 5b. While the stage 10 is reciprocated, the pulse laser 4 is irradiated over the entire width of the predetermined direction X of the irradiated object 5. In reality, after that, the stage 10 is displaced in a direction orthogonal to the predetermined direction X, and the irradiated object is irradiated with the pulse laser 4 over the entire width of the predetermined direction X of the irradiated object 5. Pulse-laser 4 is irradiated on the entire surface of (5), and the irradiated object 5 whose total surface reaches a predetermined number of irradiation times (10 to 20 times) is replaced, and pulses are irradiated on the irradiated object 5 in turn. The laser 4 is irradiated.

The moving device 20 has the X axis servo 55 specifically shown in FIG. That is, the servo motor 40 is provided, and the stage 10 is intermittently or continuously moved at predetermined intervals through the ball screw mechanism (not shown) by the forward and reverse rotation of the servomotor 40.

The servo motor 40 of the moving device 20 is driven by the servo control device 60 based on the drive signal R4 shown in FIG. 3, and subtracts the moving signal Zn from the drive signal R4 to zero. When is stopped, the stage 10 and the irradiated object 5 are also stopped. In reality, after that, the servomotor 40 is driven in reverse rotation, and when the servo signal 40 becomes zero by subtracting the movement signal Zn from the drive signal R4, the servo motor 40 is stopped again, and the stage 10 and the irradiated object 5 are also stopped. do. By this repetition, the irradiated object 5 on the stage 10 is relatively reciprocated in the predetermined direction X with respect to the pulse laser 4 from the laser oscillation apparatus 1. For this reason, the rangefinder 31 mentioned later is actually the irradiation position of the pulse laser 4 to the said to-be-projected object 5, ie, the front-back direction of the advancing direction of the stage 10 from the optical axis of the reticle and the objective lens 3. It is installed symmetrically on both sides.

The movement signal Zn detects the rotation speed (rotation angle) of the servomotor 40 by the rotary encoder 41, the detection pulse is counted by the first counter 42, and the movement of the stage 10 is carried out. Each time the length becomes a predetermined value, it is obtained as a pulse signal. Therefore, the movement signal Zn corresponds to the predetermined movement length of the stage 10 for every one pulse.

The specific speed of the stage 10 moving from the right to the left in FIG. 2 by the X-axis servo 55 is about 100 to 800 mm / sec. The pulse laser 4 to be irradiated intermittently emits 50 to 1,000 times per second, for example, and the light emitting time is about 2 nsec to 10 μsec. Thus, since the time which the pulse laser 4 emits light is very short compared with the movement speed of the stage 10, it is formed in the X-axis servo 55 even if the stage 10 is continuously moved, and it is made into the predetermined direction X The pulse laser 4 can be irradiated at equal intervals by the value of the 1st counter 42 which shows the position of. That is, the drive of the stage 10 by the servomotor 40 can be irradiated without a problem even if it does not perform intermittent irradiation which stops and irradiates once at the place irradiated one by one.

This movement signal Zn is counted by the second counter 43, and the signal for oscillating the pulse laser 4 at every movement of the predetermined interval of the stage 10 whenever it becomes the count value 1 / N1 ( I) is output and the laser oscillation apparatus 1 is driven by this signal I to irradiate the pulse laser 4. Therefore, the pulse laser 4 is irradiated to the irradiated object 5 on the stage 10 in sequence at a distance and a position of predetermined intervals.

As shown in FIG. 1, the lift drive device 30, the rangefinder 31, the basic control value setting means 32, the first calculation means 33, the delay means 34, the storage means 35, and the like. The second calculating means 36 is provided.

The lift drive device 30 has a function of relatively elevating and moving the stage 10 relative to the laser oscillation device 1, the reticle 21, and the objective lens 3, and the servo is rotated in the forward and reverse directions shown in FIG. By the motor 36, the first inclined block 38 is driven and retracted in the horizontal direction via the ball screw mechanism 37. As a result, since the second inclined block 39 engaging with the first inclined block 38 on the inclined surface is elevated, the stage 10 integrated with the second inclined block 39 is raised and lowered. The first inclined block 38 is freely supported in the horizontal direction on the side of the base 22, and the stage 10 is freely supported in the up and down direction on the side of the base 22. As shown in FIG.

As shown in FIG. 2, the distance meter 31 has a predetermined distance L behind the traveling direction of the stage 10 from the irradiation position to the irradiated object 5 mounted on the stage 10 of the pulse laser 4. And the laser oscillation apparatus 1 side which becomes the base stage 22 side, and measure the distance h of the said irradiation object 5 with the pulse laser 4 irradiation surface. The distance h measured by the rangefinder 31 is located in parallel with the optical axis of the pulse laser 4 irradiated to the object 5 after passing through the reticle 21 and the objective lens 3. The distance meter 31 measures the distance h with the irradiation surface of the pulse laser 4 of the irradiated object 5 one by one at predetermined intervals, and the detection value hn is sequentially 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 constituted by a microcomputer. The basic control value setting means 32 is provided at an appropriate distance between the object 5 and the objective lens 3 mounted on the stage 10 having a uniform thickness when the surface of the object 5 is flat without irregularities. Output the corresponding basic control value (H). In other words, the basic control value H is a positioning value of the initial state of the irradiated object 5 mounted on the stage 10 when the reticle 21 is correctly imaged on the irradiated object 5, and once. If set, no change is required. The appropriate distance between the irradiation surface of the pulse laser 4 of this irradiated object 5 and the objective lens 3 corresponds to the appropriate distance h measured by the rangefinder 31.

The delay means 34 delays and outputs the detected value hn of the rangefinder 31 by a predetermined time necessary for the stage 10 to move the predetermined distance L. FIG. However, the delay means 34 may be provided so as to finally delay the control difference value δ which will be described later by a predetermined time and output the lift drive device 30. Therefore, the delay means 34 can also be arranged between the second calculation means 36 and the lift drive device 30.

The first calculating means 33 sets the 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 rangefinder 31 to H-hn = Δn. It calculates | requires by and outputs the difference value (DELTA) n.

The storage means 35 sequentially stores the difference value Δn-1 obtained last time among the difference values Δn that are sequentially output from the first calculation means 33. The second calculating means 36 sets the control difference value δ consisting of the difference between the difference value Δn-1 obtained before the memory means 35 is stored and the difference value Δn obtained next, Δn − (Δn). -1) = computed by δ.

Then, the elevating drive device 30 is driven in accordance with the control difference value δ, and the irradiated object mounted on the stage 10 is kept constant while the distance between the reticle 21 and the objective lens 3 is maintained. 5) the distance h between the irradiation surface of the pulse laser 4 and the distance between the objective lens 3 and the irradiation surface of the pulse laser 4 of the irradiated object 5 mounted on the stage 10. To be appropriate.

A detailed configuration of the automatic irradiation distance adjusting device will be described with reference to FIG. 3. The irradiation distance automatic control device is a Z-axis servo 56 for driving the signal processing unit 57 and the stage 10 in the vertical direction using the first FIFO (First In First Out) memory 45 and the second FIFO memory 46. ) And a rangefinder 31. The FIFO memories 45 and 46 are also referred to as field image memories, and are memories that can be taken out from previous data in the order of storage when data is stored and retrieved and used.

In the signal processing unit 57 using the FIFO memories 45 and 46, the movement signal Zn is counted in advance by the third counter 44, and outputs a pulse signal J whenever the count value 1 / N2 is reached. When the pulse signal J is outputted, the signal processing unit 57 operates to perform calculations using the FIFO memories 45 and 46 and the like. Therefore, the pulse signal J is generated based on the drive signal R4.

Here, when the stage 10 is moved in the predetermined direction X (X axis direction) by the moving device 20, a pulse of the movement signal Zn is generated, and the stage 10 per one pulse P is generated. The moving distance of is about 0.01 to 10 µm / P. For example, the description will be continued in the case where the moving signal Zn is 1 mu m / P. The second counter 43 counts the pulse of the moving signal Zn, outputs one pulse signal I to the laser oscillator 1 for every N1 counts, and causes the pulse laser 4 to emit light. As a specific example, N1 is 1,000 and the pulse laser 4 is irradiated at intervals of 1 mm. On the other hand, the third counter 44 outputs a pulse signal J every N2 counts, and performs calculation of the signal processing unit 57 and the like when the pulse signal J is output.

In general, the number of stages of the first FIFO memory 45 (four stages in the first FIFO memory 45 of FIG. 3) is set to M, and the detected value of the rangefinder 31 every L / M mm from the distance L mm of FIG. 2. When (hn) is taken out from the first FIFO memory 45 and calculated, the detected value hn of the rangefinder 31 is calculated by delaying the predetermined distance L by the time required for the stage 10 to move. Can be. Therefore, when the value of the count number N2 of the 3rd counter 44 is set to L / M / 1micrometer, the drive of the elevation drive device 30 can be performed according to the movement of the stage 10. If the value of N2 is made equal to the value of N1, it is possible to drive the lift drive device 30 based on the detected value hn of the distance meter 31 in accordance with the light emission of the pulse laser 4. However, it is not essential to drive the lift drive device 30 in accordance with the light emission of the pulse laser 4.

The first FIFO memory 45 inputs the detected value hn of the rangefinder 31 every predetermined time period (every N2 counts), which sequentially moves to M1, M2, M3, M4, and detects the detected value hn. ) Is delayed by a predetermined time and output from M4. Therefore, the first FIFO memory 45 is a delay means 34 for delaying and outputting the detected value hn of the rangefinder 31 by the time required for the stage 10 to move the predetermined distance L. Function. However, since the detected value hn of this rangefinder 31 is later converted into the control difference value δ, it is necessary for the stage 10 to move the control difference value δ to the predetermined distance L. The operation is the same even if the output is delayed by time.

The detection value hn taken out from the first FIFO memory 45 reaches the first calculation means 33 shown in FIG. 3 and is detected with the basic control value H output from the basic control value setting means 32. The difference value Δn of the value hn is sequentially obtained as H − hn = Δn.

The second FIFO memory 46 sequentially stores and stores the difference value Δn outputted from the first calculating means 33. Then, when the next pulse signal J is outputted, the difference value Δn between the detected value hn and the basic control value of the rangefinder 31 outputted from the first FIFO memory 45 at this time is obtained. The difference value? N is stored and stored in the second FIFO memory 46, and bypasses the second FIFO memory 46 to reach the second calculating means 36 shown in FIG.

In the second calculating means 36, the control difference value δ consisting of the difference between the previous difference value Δn-1 and the current difference value Δn taken out from the second FIFO memory 46 is Δn-(Δn). -1) = sequentially obtained as δ. Therefore, the second FIFO memory 46 functions as the storage means 35 for storing 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 36, and moves the stage 10 up and down through the ball screw mechanism 37 shown in FIG. 2 by rotating the servo motor 36 forward or reverse.

The servomotor 36 of the Z-axis servo 56 is driven while being controlled by the servo controller 61 based on the control difference value δ shown in FIG. 3, and is controlled from the control difference value δ that becomes a drive signal. It stops when the lifting movement signal Zn2 is subtracted to zero, and the stage 10 and the irradiated object 5 are also stopped. The lifting movement signal Zn2 detects the rotation speed (rotation angle) of the servomotor 36 by the rotary encoder 51, and the detection pulse is counted by the fourth counter 52, and the stage 10 Every time the lifting movement length becomes a predetermined value, it is obtained as a pulse signal. Therefore, the lift movement signal Zn2 corresponds to the predetermined lift movement length of the stage 10 for each pulse.

Next, the effect | action of the said 1 Embodiment is demonstrated.

Initially, the basic control value H is set in the basic control value setting means 32, and the distance between the irradiated object 5 mounted on the stage 10 and the objective lens 3 is basically the same in number of sheets. It is in an appropriate state with respect to the irradiated object (5). Therefore, the height position of the rangefinder 31 is in the state of the appropriate distance h, and a measurement starts from the distance h of the left end part of the to-be-projected object 5 in FIG.

Then, 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 mounted on the stage 10 is moved to the left side in FIG. The laser oscillation apparatus 1 is driven by the signal I to irradiate the pulse laser 4 at the same time. Since the rangefinder 31 starts the measurement from the distance h of the left end of the irradiated object 5, the pulse laser 4 starts irradiation from a position separated by the distance L from the left end of the irradiated object 5. do.

On the other hand, the distance h with the irradiation surface of the pulse laser 4 of the to-be-projected object 5 is measured by the distance meter 31 at predetermined intervals, and the detection value hn is sequentially delayed means 34 Is output by delaying the predetermined distance L by the time required for the stage 10 to move, input to the first calculating means 33, and the basic value from the basic control value setting means 32. The control value H is input to the first calculating means 33. The first calculation means 33 sequentially calculates the difference value? N between the basic control value H and the detection value hn whenever the detection value hn occurs.

This difference value Δn is sequentially stored in the storage means 35, and is also input to the second calculation means 36, and the difference value (previously obtained from the storage means 36 in the second calculation means 36) ( The control difference value δ (Δn− (Δn−1) = δ) consisting of the difference between Δn-1 and the difference Δn obtained thereafter is sequentially calculated.

 Then, the elevating driving device 30 is sequentially driven based on the control difference value δ obtained sequentially, and the stage 10 is applied to the laser oscillator 1, the reticle 21, and the objective lens 3. Is moved up and down relatively, and the pulse laser 4 is irradiated while making the height of the irradiation part of the irradiated object 5 on the stage 10 appropriate.

For example, when the irradiated surface of the irradiated object 5 forms a concave portion, and the difference value Δn is a negative value, the elevating drive device 30 causes the stage 10 to the reticle 21 and the objective lens 3. ) Is moved up relatively, and the height position of the irradiation surface of the irradiated object 5 at the time of irradiation of the pulse laser 4 is matched with the appropriate height by the basic control value (H). On the other hand, when the irradiated surface of the irradiated object 5 forms a convex portion and the difference value Δn is a positive value, the stage 10 is mounted on the reticle 21 and the objective lens 3 by the lifting and lowering drive device 30. It moves relatively downward, and makes the height position of the irradiation surface of the to-be-irradiated object 5 at the time of irradiation of the pulse laser 4 correspond to the suitable height by the basic control value H. Thereby, the pulse laser 4 is continuously irradiated with the reticle 21 and the objective lens 3 in a state where the height position of the irradiation surface of the irradiated object 5 is appropriate.

Next, the case where the detected value hn of the rangefinder 31 is input to the 1st FIFO memory 45 shown in FIG. 3 is demonstrated. In this case, the distance h with the irradiation surface of the pulse laser 4 of the irradiated object 5 is measured by the rangefinder 31, and when the pulse signal J is outputted, the detected value hn is sequentially turned on. It is input to the first FIFO memory 45 of the turn signal processing section 57 and the calculation using the FIFO memories 45 and 46 is executed. In other words, while the detection value hn is sequentially input to the first FIFO memory 45 which is the delay means 33, the stage 10 and the irradiated object 5 are moved, and the detection value hn of the fifth time is moved. Simultaneously with the input, the first detected value hn is output to the first FIFO memory 45. This delayed detection value hn reaches the calculation means 33, obtains the basic control value H of the basic control value setting means 32, and calculates the difference value? N. 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 outputted, 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. The difference value Δn-1 obtained as before is entered into the second calculating means 36, and the previous difference value Δn-1 obtained from the second FIFO memory 46 in the second calculating means 36 and the present time. The control difference value δ (Δn− (Δn−1) = δ) is calculated from the difference of the difference value Δn.

The lifting drive device 30 is driven based on this control difference value δ, and the stage 10 is moved up and down relative to the laser oscillation device 1, the reticle 21 and the objective lens 3, The pulse laser 4 is irradiated, controlling the height of the irradiation part of the to-be-projected object 5 on the stage 10 suitably.

Thus, the distance between the objective lens 3 and the irradiated object 5 is adjusted and 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. do. In this way, the image of the reticle 21 can be faithfully imaged onto the irradiated object 5 by the objective lens 3. Further, the distance meter 31 is disposed away from the optical axes of the reticle 21 and the objective lens 3, and always the distance from the objective lens 3 on the optical axis to the imaging surface (irradiation surface) of the irradiated object 5. Can be controlled constantly.

By the way, in the said 1 Embodiment, although the stage 10 was moved in the horizontal predetermined direction X with respect to the pulse laser 4 from the laser oscillation apparatus 1 by the moving apparatus 20, the stage 10 It is also possible to move the laser oscillation device 1, the optical device 9, the reticle 21, and the objective lens 3 integrally in a predetermined opposite direction X instead of moving the c). Moreover, although the stage 10 is moved up and down with respect to the laser oscillation apparatus 1, the optical apparatus 9, the reticle 21, and the objective lens 3 by the lifting drive apparatus 30, the laser oscillation apparatus 1 The optical apparatus 9, the reticle 21, and the objective lens 3 can be moved up and down as one body.

As understood by the above description, the method of automatically adjusting the irradiation distance and the apparatus according to the present invention can produce the following effects.

In the case of irradiating a laser while moving the irradiated object relative to each other, the distance meter is provided at a position away from the optical axis of the pulse laser, and the position of the irradiated object is relatively changed while keeping the distance between the reticle and the objective lens constant. The distance from the objective lens to the irradiated surface of the irradiated object can be adjusted and corrected so as to be appropriate and constant, and the image of the reticle can be faithfully imaged onto the irradiated object by the objective lens. As a result, it is possible to accurately irradiate the irradiated object with the pulse laser to obtain a high quality product.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the component of the irradiation distance automatic adjustment apparatus which concerns on one Embodiment of this invention.

Fig. 2 is a diagram similarly showing the main parts.

Fig. 3 is a diagram showing a structure for obtaining the X-axis servo for moving the stage, the Z-axis servo for operating the irradiation distance automatic control device, and the driving of the laser oscillator.

Fig.4 (a) is a front view similarly showing the state which irradiates the irradiated object on a stage with the pulse laser from a laser oscillation apparatus.

Fig. 4B is a right side view showing a state in which the pulse laser beam from the laser oscillation device is irradiated to the irradiated object on the stage.

Fig. 5 is a front view showing a device for measuring the distance between the conventional objective lens and the optical axis of the irradiated object.

Fig. 6 is a diagram showing the shape of light received by the measuring instrument in the same manner.

※ Explanation of code for main part of drawing ※

1: laser oscillation device 3: objective lens

4: pulse laser 5: irradiated object

10: stage 20: moving device

21: reticle 30: lift drive device

31: Rangefinder 32: Basic control value setting means

33: first calculation means 34: delay means

35: memory means 36: second calculation means

45: first FIFO memory 46: second FIFO memory

H: Basic control value h: Distance

hn: Detection value L: Predetermined distance

X: predetermined direction δ: control difference value

Δn: difference value Δn-1: previously obtained difference value

Claims (4)

The laser oscillation apparatus 1, the stage 10 which mounts the to-be-projected object 5, and the moving apparatus 20 which relatively moves the stage 10 with respect to the laser oscillation apparatus 1 in the predetermined direction X are carried out. And a pulse laser (4) mounted on the stage (10) equipped with a pulse laser (1) from the laser oscillation device (1), which is passed through the reticle (21) and the objective lens (3) sequentially and focused by the objective lens (3). In the irradiation distance automatic adjustment method for irradiating the object (5) at predetermined intervals, A lift driving device 30 for lifting and lowering the stage 10 relative to the laser oscillation device 1, the reticle 21 and the objective lens 3, It is provided on the side of the laser oscillation apparatus 1 with the predetermined distance L behind the advancing direction of the stage 10 from the irradiation position of the pulse laser 4 to the said to-be-projected object 5, The said to-be-projected object 5 The distance meter 31 which sequentially measures the distance h with the irradiation surface of the pulse laser 4 of the laser beam and outputs the detection value hn; Has a basic control value setting means 32 for outputting a basic control value H corresponding to a proper distance between the irradiated object 5 mounted on the stage 10 and the objective lens 3, The control difference value which consists of the difference of the difference value (DELTA) n-1 calculated | required previously, and the difference value (DELTA) n calculated | required next, while obtaining the difference value (DELTA) n between the basic control value (H) and the detected value (hn) in order. (delta) is calculated | required, and this control difference value (delta) is made to delay and output the said predetermined distance L by the time required for the stage 10 to move, By driving the lift drive device 30 according to the control difference value δ, the distance between the reticle 21 and the objective lens 3 is kept constant and is mounted on the objective lens 3 and the stage 10. A method for automatically adjusting the irradiation distance, characterized by controlling the distance of the irradiation surface of the pulse laser (4) of the irradiated object (5). The laser oscillation apparatus 1, the stage 10 which mounts the to-be-projected object 5, and the moving apparatus 20 which relatively moves the stage 10 with respect to the laser oscillation apparatus 1 in the predetermined direction X are carried out. And a pulse laser (4) mounted on the stage (10) equipped with a pulse laser (1) from the laser oscillation device (1), which is passed through the reticle (21) and the objective lens (3) sequentially and focused by the objective lens (3). In the irradiation distance automatic adjustment device for irradiating the object (5) at predetermined intervals, A lift driving device 30 for lifting and lowering the stage 10 relative to the laser oscillation device 1, the reticle 21 and the objective lens 3, It is provided on the side of the laser oscillation apparatus 1 with the predetermined distance L behind the advancing direction of the stage 10 from the irradiation position of the pulse laser 4 to the said to-be-projected object 5, The said to-be-projected object 5 The distance meter 31 which measures the distance (h) from the irradiation surface of the pulse laser (4) one by one, and outputs the detection value (hn), Basic control value setting means (32) for outputting a basic control value (H) corresponding to the distance between the irradiated object (5) mounted on the stage (10) and the objective lens (3); First calculating means 33 which sequentially obtains the difference value Δn between the basic control value H and the detected value hn; Storage means 35 for storing the previously obtained difference value? N-1; Second calculating means 36 for obtaining a control difference value δ consisting of a difference between the previously obtained difference value? N-1 and the next difference value? N; Has a delay means 34 for delaying and outputting this control difference value δ by the time required for the stage 10 to move, and outputting the predetermined distance L, The lift drive device 30 is driven in accordance with the control difference value δ so as to be mounted on the objective lens 3 and the stage 10 while keeping the distance between the reticle 21 and the objective lens 3 constant. A device for automatically adjusting the irradiation distance, characterized by controlling the distance of the irradiation surface of the pulse laser (4) of the irradiated object (5). 3. The delay means (34) according to claim 2, wherein the delay means (34) is constituted by the first FIFO memory (45), and the detection value (hn) is set by the time required for the stage 10 to move the predetermined distance (L). And outputting the delayed output to delay the output of the control difference value δ. 4. The irradiation distance automatic regulation political device according to claim 2 or 3, wherein the storage means (35) is constituted by a second FIFO memory (46).