JPS63144886A - Laser beam processing device - Google Patents

Abstract

PURPOSE:To improve the positioning speed and accuracy of a work to a laser beam processing position by providing a stage driving control part and laser beam projection system driving control part. CONSTITUTION:A stage 1 is fed at a high speed by the wafer stage driving control part 53 by which the part PP requiring processing can be quickly brought near to the projecting position of the processing laser beam LB when the part PP is apart largely from the projecting position of the laser beam LB. While the stage 1 is moved at a specified slight speed, the laser beam LB is moved by the laser beam projection system control part 52 toward the part PP when the part PP comes near to the projecting position of the laser beam LB. The positioning of the part PP and the projecting position of the laser beam LB is thus executed at the high speed with the high accuracy.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a laser processing device, and is particularly applicable to a laser processing device that processes a workpiece placed on a movable stage using a laser beam. It is.

[Conventional technology]

As this type of laser processing apparatus, for example, there is one in which a chip that has been processed is reprocessed using a laser beam for the purpose of repairing a defect in a memory chip on a semiconductor wafer. This type of processing apparatus is required to align the wafer with the laser beam processing position at high speed and with high precision.

However, in conventional laser processing equipment, the method of aligning the workpiece to the laser beam processing position is as follows:
Firstly, a method in which a stage on which a workpiece is placed is moved, and secondly, a method in which the position of a laser beam is moved using an optical system (eg, a galvano mirror) has been adopted.

[Problem that the invention seeks to solve]

The method of moving the first stage has the advantage of being able to align the processing position of the laser beam with high precision, but on the other hand,
There is a problem in that the stage on which the workpiece is placed and the mass of its drive mechanism are quite large, making it impossible to increase the positioning speed very much.

Further, while the method of moving the second laser beam has the advantage of increasing the moving speed, it has the problem that the alignment accuracy for aligning the laser beam to a predetermined processing position on the workpiece cannot be very high.

The present invention has been made in consideration of the above points, and attempts to propose a laser processing device that can realize high speed and high precision when positioning a workpiece to the processing position of the laser beam. It is something.

[Means for solving problems]

In order to solve this problem, in the present invention, the processing laser beam LB sent out from the laser beam irradiation system 5 is irradiated onto the required processing portion PP of the workpiece 4 placed on the stage 1. In a laser processing device configured to process a part to be processed PP, the part to be processed P
a stage drive control unit 53 that drives and controls the stage l to bring P closer to the irradiation position of the processing laser beam LB;
A laser beam irradiation system drive control section 52 is provided to drive and control the laser beam irradiation system 5 in order to bring the laser beam irradiation system closer. Then, while the distance XOt between the part to be processed PP and the irradiation position exceeds the predetermined value XI, the stage drive control unit 53 sets the average drive speed of the stage 1 to the first speed, and the part to be processed PP and the irradiation position are When the distance MXI becomes equal to or less than the predetermined value X1, the stage drive control section 53 drives the stage 1 while keeping the second speed constant, which is slower than the first speed, while the laser beam irradiation system drive control section 52 performs the above operation. Let it start.

Still another invention includes a stage l on which a workpiece is placed, a processing laser 13, and a laser beam irradiation system 5 that irradiates the workpiece 4 with a laser beam LB from the processing laser 13. A laser drive control unit 54 that controls laser beam irradiation, and a laser drive control unit 54 that controls the laser beam irradiation, and
, and a stage drive control section 53 that performs drive control in the Y direction. Then, if the distance between the part to be processed and the irradiation position along the Y direction of both axes becomes equal to or less than the set value prior to the distance XDt in the
The drive in the direction is stopped, and then the distance XIl in the X direction is
! The laser drive control unit 54 continues driving in the X direction even if the distance in the X direction becomes less than the set value X.
When the temperature becomes less than t, the laser beam LB is irradiated to process the required processing portion PP.

[Effect]

If configured as in the above invention, when the part to be processed PP is far away from the irradiation position of the processing laser beam LB, the stage 1 is moved at high speed to move the part to be processed PP near the irradiation position of the processing laser beam LB. You can quickly get close to it.

Then, when the part to be processed PP comes close to the irradiation position of the processing laser beam LB, the processing laser beam LB is moved toward the part to be processed PP while moving the stage 1 at a constant minute speed.

In this way, the positioning of the part to be processed PP and the irradiation position of the processing laser beam LB can be performed at high speed and with high precision.

Furthermore, if configured as in another invention, when positioning the processing target PP at the irradiation position of the laser beam LB by moving the stage 1 movable in the X and Y ring directions, the direction in which the positioning was completed first is achieved. The movement of the stage 1 is stopped when the positioning is completed, but the movement in the other direction is continued even when the positioning is completed, so that high-speed and high-precision laser processing can be realized.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a semiconductor manufacturing device will be described in detail below with reference to the drawings.

In FIG. 1, 1 is a wafer stage mounted on a base 2, and is driven by a wafer stage drive motor 3.
It is configured to be able to move in the direction and the Y direction.

A wafer 4 is placed on the top surface of the wafer stage 1 as a workpiece.
is mounted, for example, by vacuum suction, and is configured to receive the processing laser beam LB irradiated from the laser beam irradiation system 5.

The laser beam irradiation system 5 is composed of an objective lens system, and is fixed to a laser beam stage 12 provided above a pedestal 11 installed on the base 2 so as to face the wafer stage 1 with the wafer 4 in between. There is.

The laser beam LBX generated from the processing laser 13 is sent to the laser beam irradiation system 5 as a processing laser beam LB after its power is adjusted in the beam power controller 14 via the mirror 15 and the aperture 16. 5. Since the aperture 16 and the wafer 4 are in a conjugate relationship with respect to the laser beam irradiation system 5, the laser beam irradiation system 5 images the processing laser beam LB shaped into the opening shape of the aperture 16 on the wafer 4, and Process the semiconductor wafer portion at the specified position.

The laser beam stage 12 holds the laser beam irradiation system 5 movably in the X direction and the Y direction. On the other hand, a laser beam driving device 20 is provided between the laser beam irradiation system 5 and the pedestal 11 to move the laser beam irradiation system 5 in the X direction or the Y direction.

The laser beam driving device 20 has a bearing 21 fixedly held on the outer surface of the lens barrel of the laser beam irradiation system 5, as shown in the figure in the X-axis direction, and this bearing 21 has a bearing 21 fixedly held at both ends in the X-axis direction. It has a structure in which the part is held from the outside by a laser beam drive element 22 and a compression spring 23. The laser beam drive element 22 has one end connected to the pedestal 11.
It is made up of, for example, a piezo element fixed to the. The bearing 21 is pressed onto the laser beam driving element 22 by a compression spring 23 whose one end is fixed to the frame 11.

Thus, when the laser beam drive element 22 expands and contracts in proportion to the supplied voltage, the laser beam irradiation system 5 is moved in the X direction by an amount corresponding to the amount of compression and expansion of the laser beam drive element 22 due to the biasing force of the compression spring 23. Ru.

Similarly for the Y direction, the laser beam drive element 2
2 and a compression spring 23 are provided so that the laser beam irradiation system 5 can be moved in the Y-axis direction by an amount corresponding to the compression and expansion of the laser beam driving element 22.

In this way, in order to align the predetermined processing portion PP on the wafer 4 with the processing laser beam LB, the wafer stage 1
The first method involves moving the laser beam irradiation system 5 in the X direction and/or the Y direction using the laser beam drive element 22 of the laser beam drive device 20. By using one or both of the above methods, alignment can be performed by changing the relative position of the wafer 4 and the laser beam irradiation system 5.

2 shows an objective lens 5a housed in the laser beam irradiation system 5 and a lens lla fixed in the frame 11, both lenses forming an infinite system. Assume that when the objective lens 5a moves by a distance NXI from the position shown by the solid line in FIG. 2 to the position shown by the broken line in FIG. 2, the beam position on the wafer 4 moves by a distance X1. When the distance X is very small, the light beam passing through the objective lens 5a is considered to mostly pass on the optical axis of the lens, and is therefore not affected by lens aberrations.

This relationship also applies to the Y-axis direction.

Under such conditions, the irradiation position on the XY plane irradiated by the laser beam irradiation system 5 and the position of the wafer 4 on the XY plane are measured by interferometers 25 and 26, respectively.

The interferometer 25 for the laser beam irradiation system 5 fixes the parallel output beam irradiated from the wavelength-stabilized measurement laser 31 to the outer surface of the laser beam irradiation system 5 by sequentially activating beam splitters 32 and 33. detected mirror 34
The reflected light is received by the beam splinter 33. At the same time, the interferometer 25 transfers the output beam of the measurement laser 31 to the beam splitter 732.3.
3. It is configured so that the light enters a reference mirror 36 provided at a reference position of the pedestal 11 via a mirror 35, and the reflected light is returned to the beam splinter 33 via the mirror 35. Note that the nodal point on the exit side of the laser beam irradiation system 5 is set to be located on the extension line of the output beam reciprocating between the beam splinter 33 and the mirror 34. As a result, when the beam irradiation system 5 is displaced in the direction perpendicular to the optical axis and the laser beam LB is displaced in the same direction on the wafer 4, the amount of displacement of both will match, and the amount of displacement of the beam LB will be the same. The accuracy of displacement detection increases.

Thus, the beam splinter 33 is connected to the reference mirror 36.
An interference beam is obtained by causing interference between the reflected beam reflected from the detection mirror 34 and the reflected beam reflected from the detection mirror 34, and this interference beam is incident on the photoelectric sensor 37. This interference beam is generated based on the difference between the X-direction position of the reference mirror 36 and the X-direction position of the detection mirror 34 and hence the laser beam irradiation system 5. The brightness changes, and in response to this change in brightness, the photoelectric sensor 37 sends out a detection pulse DTI corresponding to the feed amount.

On the other hand, the interferometer 26 for detecting the position of the wafer 4 connects the output beam of the measurement laser 31 to the beam splinter 32,
The beam enters a detection mirror 43 fixed to the side surface of the wafer stage 1 via a mirror 41 and a beam splitter 42, and its reflected beam is received by a beam splitter 42. At the same time, the output beam of the measurement laser 31 is transferred to the beam splitter 32, the mirror 41, the beam splitter 42, and the mirror 44.
The detection beam is made incident on the above-mentioned reference mirror 36 via the mirror 44, and the reflected beam is returned to the beam splinter 42 via the mirror 44.

Thus, an interference beam is formed in the beam splitter 42 by the reflected beam from the detection mirror 43 and the reflected beam from the reference mirror 36, and a change in brightness of this interference beam is detected by the photoelectric sensor 45. The photoelectric sensor 45 receives a detection pulse D corresponding to the movement of the detection mirror 43, that is, the wafer 4 with respect to the reference position of the reference mirror 36.
T2 occurs.

In this way, from the interferometers 25 and 26, the reference mirror 3
It is possible to obtain detection pulses DTI and DT2 corresponding to the movement amount of the laser beam irradiation system 5 and the movement amount of the wafer 4, respectively, with respect to the reference position where the laser beam irradiation system 6 is provided. By controlling the drive control section of the beam irradiation system 5 and the wafer stage drive control section, the processing laser beam LB
The processed portion on the wafer 4 can be aligned to the irradiation position.

In other words, the position of the processing laser beam LB when the laser beam irradiation system 5 is at the origin on the XY plane and the position of the reference mark formed on the wafer 4 on the XYY plane are determined in advance by the processing apparatus shown in FIG. Before processing the wafer 4, the measurement is performed in advance using a separate measuring device. In addition, the positional relationship between the part to be processed PP on the wafer 4 and the reference mark formed on the wafer 4 is accurately measured in advance as a design value or as a result of measurement. Therefore, since the positional relationship on the XYY plane between the part to be processed PP on the wafer 4 and the processing laser beam LB is known in advance, the distance in the X-axis direction and Y-axis direction corresponding to the positional deviation is set as the target value. The positioning control may be performed by setting the target value and moving the wafer 4 (therefore, the wafer stage 1) and the laser beam irradiation system 5 relatively in the X direction and the Y direction so as to reach this target value.

Such alignment control is performed by a drive control device 5 shown in FIG.
1 is executed. In FIG. 3, only the drive control system in the X direction is shown, but it is assumed that the drive control system in the Y axis direction is similarly configured.

The drive control device 51 includes a laser beam irradiation system drive control section 52 for the laser beam irradiation system 5, a wafer stage drive control section 53 for the wafer stage 1, and a laser drive control section 54 for the processing laser beam a13. .

In the wafer stage drive control section 53, a counter 55
receives the detection pulse DT2 obtained from the photoelectric sensor 45, generates a count output Xc representing the current position of the stage I on the X-axis, and sends it to the subtraction input terminal of the subtraction circuit 56. A target value X0 representing the feed amount in the X-axis direction is input to the addition input terminal of the subtraction circuit 56, and the difference M
The subtraction output MDI formed by DI""X@-X- (5) is supplied to the comparison circuit 57.

In this way, the subtraction output XDI obtained from the subtraction circuit 56 is calculated based on the position of the processing laser beam LB at the reference position, which will be described later, and the part to be processed P on the wafer 4, as shown in FIG. 4(A).
This relative difference MDI represents the relative difference from the position of P, and this relative difference MDI is calculated as follows: 1=1. The value of Xet=Xo
From this, the count output X of the counter 55 increases and this becomes the target value X.

It becomes smaller as it approaches 5, and eventually reaches the counter 5.
When the count output Xc of 5 reaches the target value X0, the difference output XO+ becomes O, indicating that the positioning operation is completed.

The comparison circuit 57 compares the difference output X□ with the reference signal X1,
When the content of the difference output X111 is greater than the content of the reference signal X+, as shown in FIG. 4(B), a comparison output C0M1 that maintains the logic rLJ level is sent out. Here, the reference signal X1 switches from a mode in which positioning is performed by moving the wafer stage 1, ie, a wafer stage transport mode, to a mode in which positioning is performed by moving the laser beam irradiation system 5, ie, a laser beam irradiation system transport mode. It represents the content of the difference output XDI at the timing, and as shown in Figure 4, the difference output XDI is
When it approaches and becomes smaller than 4fi X +, the logic level of the comparison output COMI of the comparison circuit 57 is
The value is selected to invert the signal to the J level. The comparison output COMI is sent to the gate circuit 5 via the inverter 58.
given to 9.

The gate circuit 59 also receives a Y-axis positioning completion signal cy, which is inverted to the logic rHJ level when the positioning of the stage 1 and the laser beam irradiation system 5 in the Y-axis direction is completed.

The gate circuit 59 is controlled to be open regardless of the logic level of the Y-axis orientation completion signal Cy as long as the comparison output COMI is at the logic rLJ level, and both the comparison output COMI and the Y-axis orientation completion signal cy are at the logic rHJ level. When the level is reached, it is controlled to close.

When the gate circuit 59 is opened, the difference output MDI is sent to the gate circuit 5.
9. Hold circuit 81. The signal is supplied to the motor drive circuit 60 via the D/A converter 79 and the speed control circuit 82, thereby continuing to drive the wafer stage drive motor 3 (FIG. 1).

The hold circuit 81 holds the difference output X□ from the gate circuit 59 and sends it as it is to the D/A converter 79, but the comparison outputs C0M1 and C0M3 are both logic rH.
When it rises to the J level and the gate circuit 59 is controlled to close and the difference output X□ is no longer sent, the difference output Xn+ held just before is sent to the D/A converter 79.

The difference output XOI of the subtraction circuit 56 is applied to the addition input terminal of the subtraction circuit 62 through the gate circuit 61 of the laser beam irradiation system drive control section 52.

The laser beam irradiation system drive control section 52 includes a photoelectric sensor 37
The counter 63 counts the detection pulses DTI, and the count output X is applied to the subtraction input terminal of the subtraction circuit 62. The subtraction output XOX thus obtained at the output terminal of the subtraction circuit 62 is applied to the laser beam drive circuit 64 via the D/A converter 80. At this time, the laser beam drive circuit 64 is connected to the laser beam drive element 2 made of a piezo element.
2, the drive output DR2 is sent out. As a result, the laser beam irradiation system 5 is driven and controlled until the count output X of the counter 63 is equal to the value at the addition input terminal. Thus, when the difference output XDI of the subtraction circuit 56 reaches the mode switching level X shown in FIG. 4(A), the data of the relative difference remaining between the target value x0 and the position (=Xl> is given to the subtraction circuit 62 as an addition input, so that the count output X of the counter 63
The laser beam irradiation system 5 is driven until the difference output Xot (≦X+) matches the remaining difference output Xot (≦X+).

In addition to the above configuration, the laser beam irradiation system drive control section 52 inputs the reference position data X of the reference position data generation circuit 71 to the addition input terminal of the subtraction circuit 62. , has a configuration given through gate circuit l572.

The comparison output C0M1 of the comparison circuit 57 is applied to the gate circuit 72 as an open control signal via an inverter 73, so that the gate circuit 72 operates in the opposite direction to that of the gate circuit 61.

In this way, while the comparison output COMI is logic rLJ and therefore the gate circuit 61 is in the closing operation, the gate circuit 72 is in the closing operation and the reference position data X is sent to the subtraction circuit 62. ll is supplied, and as a result, the laser beam drive circuit 64 drives the laser beam drive element 22, thereby bringing the irradiation position of the processing laser beam LB to a reference position as a home position. In this embodiment, reference position data X. R is selected to a value that causes the processing laser beam LB to irradiate the coordinate origin on the 52, the processing laser beam LB positions the origin on the X-axis at a position where it can be irradiated.

Subtraction output XI1 of the subtraction circuit 62. is given to the comparison circuit 75 of the laser drive control section 54. The comparison circuit 75 outputs a comparison output C0M2 (fourth
(C)) and supplies it to the input terminal of the gate circuit 76. Here, the value of the reference signal X2 is the stage l
The signal level is preselected to represent a permissible range in which it can be considered that the alignment of the laser beam 1 and the irradiation system 5 on the X axis is completed.

The gate circuit 76 receives the above-mentioned comparison outputs COMI and C0M2.
When the positioning of the stage 1 and the laser beam irradiation system 5 is completed on the X-axis and both comparison outputs C0M1 and C0M2 reach the logic rHJ level, the X-axis positioning completion signal CX at the logic rHJ level is sent to the gate circuit 77. send to

The gate circuit 77 is also supplied with the aforementioned Y-axis direction positioning completion signal cy, which becomes the logic rHJ level when the positioning of the stage 1 and the laser beam irradiation system 5 is completed on the Y-axis. When the beam LB becomes available for irradiation and both positioning signals Cx and Cy reach the logic rHJ level, the gate circuit 77 becomes open. As a result, the trigger output TR of the laser Q-switch trigger oscillator 78
G is supplied to the processing laser 13. As a result, the processing laser 13 generates a laser beam LBX (FIG. 1) and irradiates the wafer 4 with the processing laser beam LB.

In the above configuration, at time t in FIG. 4, the positioning on the Y axis has already been completed, and the stage 1 and the beam irradiation system 5 are
stops the displacement in the Y-axis direction, so the logic rH
It is assumed that the Y-axis direction positioning completion signal cy of J level is input to the gate circuit 59.77. At this time again,
Processing laser beam LM (located at the origin 0 position on the X axis,
In addition, the part to be processed PP of the wafer 4 is at the position of the target value X0, and from this state the wafer stage drive control unit 53 starts driving.
Start M control operation. In other words, it's time. In this case, when the wafer stage 1 has not started operating, the photoelectric sensor 45 has not yet sent out the detection pulse DT2, so the counter 55 output X is O, and therefore the difference output X of the subtraction circuit 56 is O. , , is the target value X0, and has a larger value than the reference signal X of the comparison circuit 57.

Therefore, the comparison output COMI of the comparison circuit 57 is at the logic rLJ level, so the gate circuits 59 and 72 open.
And the gate circuits 61 and 76 are in a closed state.

As a result, the difference output X111 from the subtraction circuit 56 is converted into an analog signal by the D/A converter 79 via the gate circuit 59 and the hold circuit 81, and
added to. The speed control circuit 82 generates a speed control signal corresponding to this analog signal, and the motor drive circuit 6o
send to The motor drive circuit 60 amplifies this speed control signal to generate a drive output DR, and sends it to the wafer stage drive morph 3. As a result, the drive motor 3 is started, and the target portion PP of the wafer 4 starts moving toward the point where it can be irradiated with the processing laser beam LB, that is, the origin 0 on the X-axis. Eventually, the photoelectric sensor 45 generates a detection pulse DT2 representing the amount of movement of the part to be processed PP.
The speed control circuit 8 in which the count output X of 5 increases and the difference output XDI decreases toward 0.
2 receives a speed signal indicating the rotational speed of the motor 3 from a tacho generator built in the drive motor 3 while the stage drive motor 3 is rotating, and generates a speed control signal generated based on the difference output X, . This speed control signal is controlled so that the speed signal corresponds to the motor 3, that is, the stage l, as the distance difference indicated by the difference output
This signal tends to drive the stage 1 at a low speed, and finally stops the stage 1 when the distance difference disappears.

Thus, the position of the required processing part PP of the wafer 4 approaches the irradiation position of the processing laser beam LB together with the wafer stage 1. In this operation mode, the subtraction circuit 62 of the laser beam irradiation system drive control section 52 has a reference position Reference position data X of the data generation circuit 71. 1 is given, and the laser beam drive circuit 64 outputs a drive output to the laser beam drive element 22 so that the value of the counter 63 matches the origin position on the X axis represented by this reference position data XOI. DR1 is given, and the processing laser beam LB maintains a state in which it can irradiate the origin.

Eventually, at time t1 in FIG. 4(A), when the difference output X becomes smaller than the reference signal X1, the comparison output C0M1 of the comparison circuit 57 rises to the logic rHJ level (the fourth
(B)), the gate circuits 59 and 72 are thereby controlled to close, and the gate circuit 61 is controlled to be opened.

Therefore, the hold circuit 81 sends the difference output X'DI held just before to the D/A converter 79, and as a result, after time t1, the drive output D R+ for the wafer stage drive motor 3 is switched to a constant voltage, The position of the required processing portion PP of the wafer 4 moves at a constant minute speed. This speed is set to a value that allows the laser beam irradiation system 5, which is driven as described later, to sufficiently follow the movement of the processing target PP.

On the other hand, the subtraction circuit 62 of the laser beam irradiation system drive control section 52
, the subtraction circuit 5 is used instead of the reference position data X0II.
The state is switched to a state where the difference output X of 6 is given through the gate circuit 61. As a result, the difference output XDz of the subtraction circuit 62
suddenly changes to a value corresponding to the difference between the irradiation position of the processing laser beam LB (that is, the origin) and the value of the difference output XDI of the subtraction circuit 56, and as a result, the laser beam from the laser beam drive circuit 64 A drive output D Rt to the drive element 22 is sent out. Therefore, laser beam LB
The position that can be irradiated starts moving toward the position of the part to be processed PP from time t, and the amount of movement is detected by the photoelectric sensor 37.
As a result, the count output XF of the counter 63 increases and the value of the difference output XOZ decreases.

Eventually, at time 1t, the difference output XIl of the subtraction circuit 62
! When the comparison output C0M2 becomes smaller than the reference signal X2 of the comparison circuit 75, the comparison output C0M2 of the comparison circuit 75 rises to the logic rHJ level (FIG. 4(C)). Given. At this time, since the Y-axis direction positioning completion signal cy at the logic rHJ level has already been applied to the gate circuit 77, the gate circuit 77 is controlled to open, and the processing laser 13
A drive output DR3 is sent out.

As a result, the processing laser beam LB is irradiated onto the wafer 4. The position of the processing laser beam LB at this time is within the laser irradiation permissible range represented by the reference signal X2, and thus the required processing portion PP of the wafer 4 is processed by the processing laser beam LB.

At time t after this machining is completed, the machining operation for one processing target portion PP is completed, and then the target position manual power X of the wafer stage drive control section 53 is reached. is changed to a target value xe' (assuming that the value in the Y-axis direction does not change) that specifies the position of the next part to be processed PP'. At this time, the difference output X between the target position human power Xe' and the counter output XC representing the current position of stage l is larger than the reference signal X, so the comparison output COMI of the comparison circuit 57 is set to logic rL.
J level, and positioning for a new target position X, l is started by the motor drive circuit 60 in the same way as the operation between times t and t.

Further, since the comparison output C0M1 is the logic rLJ, while the gate circuit 61 is closed, the gate circuit 72 is closed, and the reference position data XOI is supplied to the subtraction circuit 62.
As a result, the laser beam drive circuit 64 drives the laser beam drive element 22, thereby starting the operation of returning the irradiation position of the processing laser beam LB to the origin position as the home position.

At time t, the difference output X is the reference signal X.

When the temperature drops below this point, the laser beam irradiation system drive control section 52 and the wafer stage drive control section 53 start the same operation as between times t1 and tz. That is, at time t4, the comparison output COMI of the comparison circuit 57 rises to the logic "I(" level) (FIG. 4(B)), thereby controlling the gate circuits 59 and 72 to close and controlling the gate circuit 61 to open. Ru.

Therefore, in the wafer stage control unit 53, the hold circuit 81 sends the previously held difference output XDI to the D/A converter 79, and thereafter the drive output DR to the wafer stage drive motor 3 is switched to a constant voltage. , the position of the required processing portion PP' of the wafer 4 moves at a constant minute speed. On the other hand, the subtraction circuit 62 of the laser beam irradiation system drive control section 52 is switched to a state in which the difference output X of the subtraction circuit 56 is applied via the gate circuit 61.

As a result, the difference output XDZ of the subtraction circuit 62 is the difference between the irradiation position of the processing laser beam LB indicated by the counter output XF at time t4 and the difference output XDI of the subtraction circuit 56 (i.e.,
+), and a corresponding drive output DRi is sent out from the laser beam drive circuit 64.

Therefore, the position that can be irradiated with the laser beam LB is at the time t4.
It starts moving toward the position of the part to be processed PP'.

Eventually, at time t, when the difference output X of the subtraction circuit 62 becomes smaller than the reference signal Xt of the comparison circuit 75, the comparison output C0M2 of the comparison circuit 75 rises to the logic rHJ level (FIG. 4(C)). This change in the comparison output C0M2 is given to the gate circuit 77 via the gate circuit 76,
By controlling this to open, the laser Q trigger oscillator 7
A drive output D Rs to the processing laser 13 is sent out based on the trigger output TRG of 8, and the processing laser beam LB is irradiated to the processing target portion PP' on the wafer 4.

At the time t when this machining is completed, the part to be machined PP'
The processing operation for the part P is completed, and then the value of the target position manual force Xo' of the wafer stage drive control unit 53 is set to the next part P to be processed.
The target value is changed to X02, which specifies the position of P', and the same operation as described above is performed. However, since the difference output XDI between the target position human power X,'' and the counter output Xc representing the current position of the stage l is smaller than the reference signal X1, the laser beam irradiation system 5 is used between time points t and t4. The machine immediately starts moving toward the part to be processed PP'' without performing such a return operation to the origin position.

In the above embodiment, the distance between the stage 1 and the laser beam irradiation position is reduced, and the difference output XDI becomes the reference signal X,
Although the moving speed of the stage 1 was fixed at the speed at that point after the value became smaller, the present invention is not limited to this, and the moving speed of the stage 1 is fixed at a constant speed that allows the laser beam irradiation system 5 to follow the movement of the processing target part PP. If so, it may be increased or decreased somewhat. However, the difference output X1ll is it1! The average speed of stage 1 until the signal X1 becomes smaller, ie from time t0 to t.

A necessary condition for obtaining the effect of speeding up is that the average speed of stage 1 up to this point is faster than the constant speed thereafter.

In the above embodiment, when positioning in the Y-axis direction is completed earlier than in the X-axis direction, that is, before the X-axis positioning signal Cx, the Y-axis positioning completion signal cy is inverted to the logic rHJ level. However, in the opposite case, the positioning signal Cx is generated, the stage 1 and the beam irradiation system 5 stop displacement in the X-axis direction, and the position of the part to be processed in the Y-axis direction and the beam After the distance to the position of the irradiation system 5 in the Y-axis direction approaches within a predetermined range, the stage 1 is displaced in the Y-axis direction at a constant slow speed, and in response to the generation of the positioning signal Cy, the laser beam LB is directed to the part to be processed. It becomes C which irradiates to.

According to the configuration of the embodiment described above, when there is a large difference between the irradiation position of the processing target PP and the processing laser beam LB, the wafer stage 1 is driven at high speed, so that the processing target PP of the wafer 4 is irradiated with the processing laser beam LB. As a result, when the position of the part to be processed PP approaches the position near the processing laser beam LB, the processing laser beam LB is moved while moving the wafer stage 1 at a constant minute speed. By switching to the operation mode that moves the wafer stage, it is possible to move the wafer stage with high precision by moving the wafer stage over long distances. By moving the position of the laser beam LB using the beam driving element 22, it is possible to align the laser beam LB on the target part PP at high speed.

In addition, since the driving range of the laser beam driving element 22 can be made sufficiently small, an element suitable for operating in the narrow range with high precision can be selected as the laser beam driving element 22, thereby making it possible to control the processing laser beam LB. Processing part PP
It is possible to perform alignment with a sufficiently high precision for practical use.

In addition, since the stage 3 is driven continuously, the same wafer 4
When continuously machining the above plurality of parts to be processed PP, PP', no time is wasted when moving from one part to be processed PP to another part to be processed PP'. Therefore, high-speed alignment can be performed.

Further, in the above description, a case has been described in which the present invention is applied to wafer repair, but the present invention is not limited to this, and can be widely applied to generally laser processing a predetermined position on a workpiece.

〔Effect of the invention〕

As described above, according to the present invention, while the distance between the required processing part PP processing part and the processing laser beam is large, the stage on which the workpiece is placed is driven by driving the required processing part side. The mechanism can be used to approach the target position at high speed. At the same time, when the distance between the part to be processed and the processing laser beam becomes sufficiently small, the position of the part to be processed is moved by driving the laser beam irradiation system while feeding the part to be processed at a constant micro speed. The processing laser beam can be aligned at high speed and with high accuracy at 9 degrees.

According to still another invention, when positioning the part to be processed at the laser beam irradiation position by moving the stage movable in the X and Y rotation directions, the stage movement in the direction in which the positioning was completed first is the positioning. It stops when positioning is completed, but movement in the other direction is 41 even when positioning is completed! Since the process is continuous, high-speed and high-precision laser processing can be achieved.

Both inventions can provide a laser beam processing device that can easily achieve high-speed and high-precision positioning.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the mechanical structure of the laser processing device according to the present invention, and FIG. 2 is a route diagram showing the state of movement of the laser beam irradiation position when the laser beam irradiation system is moved.
FIG. 3 is a block diagram showing a drive control device that controls the device shown in FIG. 1, and FIG. 4 is a time chart for explaining the positioning operation. 1...Wafer stage, 2...Base, 3...Wafer stage drive motor, 4...
...Wafer, 5...Laser beam irradiation system, 1
1... Frame, 12... Laser beam stage, 13... Processing stage, 14...
... Beam power control section, 20 ... Laser beam drive device, 21 ... Bearing, 22 ...
... Laser beam drive element, 23 ... Compression spring, 25 ... Interferometer for detecting the position of the laser beam irradiation system, 26 ... Interferometer for detecting the position of the wafer stage, 31...Measurement laser, 51...
Drive control device, 52... Laser beam irradiation system drive control unit, 53... Wafer stage drive control unit, 54... Laser drive control unit.

Claims (3)

[Claims] (1) In a laser processing device that processes the required processing portion of a workpiece placed on a stage by irradiating the required processing portion with a processing laser beam sent out from a laser beam irradiation system, a stage drive control unit that drives and controls the stage so as to bring the part closer to the irradiation position of the processing laser beam; and a stage drive control unit that drives and controls the laser beam irradiation system to bring the irradiation position of the processing laser beam closer to the part to be processed. a laser beam irradiation system drive control section, while the distance between the part to be processed and the irradiation position exceeds a predetermined value, the stage drive control section controls the stage so that the average speed becomes a first speed. controlling the drive, and when the distance between the part to be processed and the irradiation position becomes equal to or less than a predetermined value, the stage drive control unit controls the drive of the stage while keeping a constant second speed slower than the first speed; A laser processing apparatus, wherein the laser beam irradiation system drive control section starts the drive control. (2) While the distance between the part to be processed and the irradiation position exceeds a predetermined value, the stage drive control unit controls the drive speed of the stage as the distance between the part to be processed and the irradiation position decreases. Drive-controlling the stage to gradually reduce the speed to a predetermined speed, and when the distance between the target part to be processed and the irradiation position becomes equal to or less than a predetermined value, controlling the drive of the stage at the predetermined speed or a constant speed in the vicinity thereof. A laser processing apparatus according to claim 1, characterized in that: (3) A stage on which a workpiece is placed, a processing laser, a laser beam irradiation system that irradiates a laser beam from the processing laser toward the workpiece, and controls irradiation of the laser beam. a stage drive control unit capable of simultaneously controlling the stage in two orthogonal directions in order to bring the required processing portion of the workpiece closer to the irradiation position of the laser beam; The stage drive control unit stops driving the stage in the one direction when the distance between the part to be processed and the irradiation position along the one direction becomes equal to or less than a set value prior to the distance in the other direction, Thereafter, the drive in the other direction is continued even if the distance in the other direction becomes less than or equal to the set value, and the laser drive control unit controls the laser beam when the distance in the other direction becomes less than or equal to the set value. A laser processing apparatus characterized in that the above-mentioned required processing portion is processed by irradiating the laser beam.