JP2001276986A - Laser processing apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-speed, highly stable laser processing system concerning a laser processing apparatus provided for a large-scale glass substrate and the like, in which a focused point for processing is fed back to a subject substrate by measuring a warped amount in advance when occurred a gap of the focused point for processing caused by bending owing to an own weight of the glass substrate and the like, and in which a stable processing performance can be maintained. SOLUTION: The system is provided with a warp measuring portion 6 measuring a warped amount of a processing object in advance, a measuring and feedback controlling portion 2 determining a warped function showing the warped amount at a full range of the processed object, and Z axis portion 5 adjusting a focusing point of a laser beam on the object by moving an object lens focusing the laser beam for processing while referring to the warped function or by moving the object up and down.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus and method, and more particularly, to a laser processing apparatus and method for feedback-controlling the focal point of a processing laser beam along deflection of a substrate or the like due to its own weight.

[0002]

2. Description of the Related Art Conventionally, glass measurement has not been stable and has not been put to practical use. Therefore, a method has been adopted in which the stage is stopped, the image is focused by an image processing method, and processing is performed on the spot.

[0003]

The conventional laser processing apparatus employs a method in which the stage is stopped and the image processing method is used to focus and perform processing on the spot, thereby absorbing a large deflection of the target substrate. As a result, stable laser processing could not be performed at high speed.

[0004] An object of the present invention is to solve the above problems,
In laser processing equipment for large glass substrates, etc., even if the processing focus shifts due to bending due to its own weight of the glass substrate, etc., the processing focus is measured in advance by a sensor to move the processing focus to the target substrate. It is an object of the present invention to provide a high-speed, high-stability laser processing system that can feed back and maintain stable processing performance.

[0005]

SUMMARY OF THE INVENTION A laser processing apparatus according to the present invention comprises: a warp measuring means for measuring a warpage amount of an object to be processed in advance; A warp function determining means for determining a warp deflection function indicating the entire area of the warp, and moving the objective lens for converging the processing laser light while referring to the warp function, or moving the object up and down, Focus control means for focusing the light on the object.

According to the present invention, by measuring the amount of warpage of a substrate in advance, stable processing quality can be obtained even for a substrate having a large warpage, and high-speed control can be performed during processing. Throughput can also be improved.

[0007]

Next, an embodiment of the present invention will be described in detail.

FIG. 1 shows a first embodiment of a laser processing apparatus according to the present invention.
It is a block diagram showing an embodiment.

Referring to FIG. 1, this embodiment includes a main control unit 1, a measurement / feedback control unit 2, a laser control unit 3, an XY stage control unit 4, a Z-axis unit 5, a warp measurement unit. 6, a laser processing unit 7, and an XY stage unit 8.

The main controller 1 outputs a board warpage measurement command to the measurement / feedback controller 2. In addition, the main control unit 1 outputs an operation command to move the substrate 9 to the XY station control unit 4 so that the warp measurement unit 6 can measure the diagonal line of the substrate 9. Further, it controls the laser control unit 3 for controlling the processing laser light.

The warp measuring unit 6 includes an A / D converter 61, a sensor amplifier 62, and a board warpage measuring sensor 63. The substrate warpage measurement sensor 63 measures the distance to the front surface or the back surface of the substrate, and is output from the sensor amplifier 62 as an analog voltage. This output enters the A / D converter 61 and is converted into a digital signal.
Is transmitted to This information and the information of the XY-axis encoder / linear scale pulse high-speed counter 54 of the Z-axis unit 5 are:
The measurement / feedback control unit 2 stores the data in association with the XY coordinate values. By continuously performing these operations, the substrate 9 at a plurality of points on the diagonal line of the substrate 9 is
Is measured in the entire area of the substrate 9, and finally, the measurement / feedback control unit 2 determines a warp function indicating the amount of warpage in the entire area of the substrate 9.

The Z-axis unit 5 includes a Z-axis motor controller 5
1, a Z-axis motor driver 52, and a Z-axis motor 53
And a XY-axis encoder / linear scale pulse high-speed counter 54 and a Z-axis elevating stage 55. Z
The axis motor controller 51 controls the Z-axis motor driver 52 in accordance with the Z-axis command from the higher-order measurement / feedback controller 2. The Z-axis motor 53 is connected to the Z-axis elevating stage 55. When the Z-axis motor 53 is controlled, the slide portion of the Z-axis elevating stage 55 moves up and down. As a result, the objective lens 72 of the laser processing unit 7 moves up and down. . The XY axis encoder / linear scale pulse high-speed counter 54 is used to acquire the current position information of the XY stage as described above. Further, the positional information (XY coordinate values) of the substrate 9 is used to control the Z-axis by the amount of warp and the amount of warp obtained by being applied to the warp warp function. The Z-axis unit 5 has a substrate elevating unit (not shown) that elevates and lowers the substrate 9, moves the objective lens 72 and elevates the substrate 9, and focuses the processing laser light on the substrate. It may be configured as follows. Alternatively, the substrate 9 alone may be moved up and down so that the laser beam for processing is focused on the substrate.

The laser processing section 7 includes a laser 71 controlled by a laser control section and an objective lens 72. The laser 71 is a main body that processes the substrate 9, and the laser beam output from the laser 71 is transmitted to the objective lens 72 via an expander or the like. The objective lens 72 is fixed to the slide side of the Z-axis elevating stage 55 of the Z-axis unit 5 and moves up and down by controlling the Z-axis motor 53.

The XY stage section 8 includes an XY stage control section 81, a pulse distributor 82, an XY stage encoder / linear scale 83, and an XY stage motor 84. The XY stage encoder / linear scale 83 is attached to the XY stage 10, and transmits the current position information of the stage to the XY stage driver unit 81 in pulses.

The XY stage controller 4 controls an XY stage motor 84 using an XY stage driver 81 in accordance with a command from the main controller 1. The pulse distributor 82 has X
The pulse information enters between the Y stage encoder / linear scale 83 and the XY stage driver unit, and the pulse information is also distributed and transmitted to the Z axis unit XY axis encoder / linear scale pulse high speed counter.

The substrate 9 is fixed on an XY stage 10. Since the back surface of the substrate 9 cannot be touched due to processing restrictions, when the substrate is enlarged to 1 m × 1 m or the like, the deflection due to its own weight cannot be ignored.

Next, the operation of this embodiment will be described in detail with reference to FIG.

FIG. 2 is a flowchart showing the operations of the warpage measurement and the objective lens height control of the substrate of FIG.

First, the main controller 1 issues a board warpage measurement command,
Output to the measurement / feedback control unit 2 (step S1). The main control unit 1 thereafter outputs an operation command to the XY station control unit 4 so that the substrate warpage sensor 63 can measure the diagonal line of the substrate 9 on the substrate 9 with a locus as shown in FIG. (Step S2). At this time, the measurement / feedback control unit 2 controls the Z-axis height to the measurement height to measure the warpage of the substrate 9 by the substrate warpage measurement sensor 63.
This is performed using At the same time, the measurement / feedback control unit 2 recognizes the position of the XY stage 10 from the pulse count value obtained from the Z-axis unit XY-axis encoder / linear scale pulse high-speed counter 54. It is determined whether or not the measurement is completed (step S3).
And this measurement is repeated until the measurement is completed.

The data obtained as a result is as follows. (X-axis position data X1, Y-axis position data Y1, measurement data Z1) (X-axis position data X2, Y-axis position data Y2, measurement data Z2) ... (X-axis position data Xn-1, Y-axis position data Yn- 1, measurement data Zn-1) (X-axis position data Xn, Y-axis position data Yn, measurement data Zn) Next, a substrate warping function is determined based on the obtained data (step S4). Note that the substrate warpage function F (x, y)
Can be generally expressed as: F (x, y) = C (x−a) n (x + a) n (y−b)
n (y + b) n Here, x and y represent arbitrary positions when the center position of the substrate 9 is taken as the origin as shown in FIG. 4, and a and b are の 長 of the vertical and horizontal dimensions of the substrate. Represents In step S4, C and n in the general equation of the substrate warping function F (x, y) are determined from the plural sets of X-axis position data, Y-axis position data, and measurement data.

Then, the machining operation is started (Step S)
5). That is, the main control unit 1 outputs a machining command to the measurement feedback control unit 2. Upon receiving the processing command, the measurement feedback control unit 2 determines the coordinates x, of the processing position from the XY position information from the pulse distributor 82 of the XY stage unit 8 and the relative distance information between the substrate warpage sensor 63 and the objective lens 72. y is calculated (step S6), and this is substituted into the substrate warping function F (x, y) to calculate the amount of warpage at that position (step S7). The pulses corresponding to the correction amount obtained from this result are transmitted to the Z-axis controller 51 to control the Z-axis motor 53 (step S8). Then, it is determined whether or not the processing has been completed (step S9). If not completed, the process returns to step S6, and this is repeated continuously.

By the above operation, the processing can be performed while keeping the distance between the objective lens 72 and the substrate 9 almost constant, and the warpage of the substrate can be expressed as a relatively simple function. Can be reduced, and the number of feedbacks per unit time can be increased, so that high-speed control can be performed at the time of machining and the throughput can be improved.

Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 5, in the present embodiment, the laser processing unit 7 has a multi-beam (see FIG. 1) structure while the laser processing unit in the first embodiment shown in FIG. 5 has four beams). Also,
The same processing is performed for substrate warpage measurement, but when processing is performed,
Since the processing position of each beam is different, the x and y coordinates of the processing point of each beam are respectively calculated for the four points by the following equations. x1 = x + [Delta] xb1 y1 = y + [Delta] yb1 x2 = x + [Delta] xb2 y2 = y + [Delta] yb2 x3 = x + [Delta] xb3 y3 = y + [Delta] yb3 x4 = x + [Delta] xb4 y4 = y + [Delta] yb4 Here, x1, x2, x3, and x4 are x, y at the coordinates of x1, y2, and y at x2. , Y3, y4 are the y coordinates of the processing point of each beam, x, y are the xy coordinates of the measurement point of the measurement sensor, Δxb1, Δxb2, Δxb3, Δ
xb4 is an offset amount in the x-axis direction from the measurement sensor to each beam processing point, and Δyb1, Δyb2, Δyb
3, Δyb4 represents the offset amount in the y-axis direction from the measurement sensor to each beam processing point.

The warp function F (x, y) is such that when the measurement sensor is at the position of (x, y), the Z-axis warp feedback height of each beam is F (x1, y1), F (x
2, y2), F (x3, y3) and F (x4, y4). By continuously repeating this feedback, each beam can be controlled independently.

[0026]

As described above, according to the present invention, by measuring the amount of warpage of a substrate in advance, a stable processing quality can be obtained even for a substrate having a large warpage, Can perform high-speed control, thereby improving the throughput.

The reason is that the warpage of the substrate can be expressed as a relatively simple function, so that the calculation time can be reduced and the number of feedbacks per unit time can be increased.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a flowchart showing operations of measuring the warpage of the substrate and controlling the height of an objective lens in FIG. 1;

FIG. 3 is an explanatory diagram showing the movement of an XY stage at the time of sampling substrate warpage data in step S2 of FIG. 2;

FIG. 4 is an explanatory diagram showing a positional relationship of coordinates (x, y) on a substrate with respect to the outer shape of the substrate.

FIG. 5 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Main control part 2 Measurement / feedback control part 3 Laser control part 4 XY stage control part 5 Z-axis part 6 Warpage measurement part 7 Laser processing part 8 XY stage part 9 Substrate 10 XY stage 51 Z-axis motor controller part 52 Z-axis motor Driver unit 53 Z-axis motor 54 XY-axis encoder / linear scale pulse high-speed counter 55 Z-axis elevating stage 61 A / D conversion unit 62 Sensor amplifier unit 63 Board warpage measurement sensor 71 Laser 72 Objective lens 81 XY stage control unit 82 Pulse distributor 83 XY stage encoder / linear scale 84 XY stage motor

Claims (6)

[Claims] 1. A warp measuring means for measuring the amount of warpage of an object to be processed in advance, and applying a measurement result of the amount of warp to a basic function to determine a warp bending function indicating the entire area of the object to be processed. Warp function determining means, while referring to the warp function, moving the objective lens for converging the processing laser light, or moving the object up and down, focus control means to focus the laser light on the object A laser processing apparatus comprising: 2. A first step of measuring the amount of warpage of an object to be processed such as a glass substrate, and applying the measurement result of the amount of warpage to a basic function to determine a warp function indicating the warpage of the entire object. And a second step. 3. The method according to claim 1, wherein the first step measures a limited area on a diagonal line, and the second step determines the warp function from a measurement result obtained by measuring the limited area on a diagonal line. The laser processing method according to claim 2, wherein 4. A method for controlling the focus of the laser light and the object by moving an objective lens for converging the processing laser light or moving the object up and down while referring to the warp function. The laser processing method according to claim 2, further comprising a third step. 5. The method according to claim 1, wherein the third step includes a step of obtaining an offset amount between the measurement point and the processing point; and a step of calculating a correction amount for warpage at the corresponding measurement point with reference to the warp function. 5. The method according to claim 4, wherein
2. The laser processing method according to 1. above. 6. The method according to claim 1, wherein the third step is a step of obtaining an offset amount between the measurement point and the plurality of processing points, and the step of correcting a warpage at the measurement point for each processing point with reference to the warp function. 5. The laser according to claim 4, further comprising a step of calculating the amount of each laser beam and a step of independently focusing a processing laser beam at each processing point on an object based on a correction amount for each processing point. Processing method.