JP2000329523A - Position calibration device for alignment scope and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make easily and accurately performable the position calibration of an alignment scope by using a reference mask. SOLUTION: Prior to a specific processing to a printed circuit board S put a mounting table 15 in a processing part 21, the device calibrates the position of an alignment scope 33 for measuring the printed circuit board S. In this case, a reference mask RM where a reference pattern PR is formed is provided on the mounting table 15. After the alignment scope 33 is moved to the reference pattern PR in a specific position, the alignment scope 33 position is calibrated based on the position shift of the cross point of the reference pattern PR from the view center of the alignment scope. No length measurement device such as a linear scale is necessary and the position calibration of the alignment scope can be easily and accurately done with a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alignment scope provided in a manufacturing apparatus or the like for performing a predetermined process on a processing target such as a printed circuit board, and for measuring the processing target prior to the processing. The present invention relates to a position calibration device and a method thereof.

[0002]

2. Description of the Related Art As a conventional apparatus of this type, there is, for example, an apparatus provided in a printed circuit board manufacturing apparatus. The apparatus includes a drawing stage on which a printed circuit board is placed, and a processing unit that deflects and irradiates the drawing stage with a laser beam at a predetermined processing position.
A process for directly drawing a required pattern on a printed circuit board by a laser beam is performed. The drawing stage is, for example, mounted on a linear guide and moved with respect to the processing unit by a feed screw connected to a motor shaft.

Also, two alignment scopes for measuring the positions of reference holes and reference marks formed at the four corners of the substrate are provided above the drawing stage on the processing unit side with the moving direction therebetween. . Each alignment scope is attached to a scope stage arranged above the drawing stage. A linear guide is attached to these scope stages in a direction perpendicular to the direction of movement of the drawing stage, and the alignment scope is moved along the guide rails by a feed screw connected to the motor shaft. . The position of each alignment scope is detected by a linear scale attached to the processing section along the guide rail.

In the apparatus configured as described above, before the drawing stage on which the printed circuit board is mounted is moved with respect to the processing unit to perform the drawing process, the four corners of the board mounted on the drawing stage are processed. The position of the reference hole formed in is measured in advance with an alignment scope. Specifically, by moving the drawing stage to the processing unit side and moving each alignment scope in a direction perpendicular to the moving direction, the alignment scope is aligned above the reference hole of the printed circuit board formed on the processing unit side. Position the scope. At this time, the position of the alignment scope (the center of the optical system) is detected by the above-described linear scale, and the reference position of the alignment scope is determined.

[0005]

However, the prior art having such a structure has the following problems. In other words, the position of the center of the optical system of the alignment scope and the position of the linear scale are structurally separated, and the movement error (rolling, pitching, etc.) generated when the scope stage equipped with the alignment scope operates. For this reason, there is a problem that the accuracy of detecting the position of the center of the optical system of the alignment scope is reduced due to the above-mentioned problem. Therefore, there is a problem that the position measurement accuracy of the reference hole of the printed circuit board measured based on the detected position of the alignment scope is low.

Further, when the mounting posture of the alignment scope with respect to the scope stage is shifted, there is also a problem that it is very difficult to return the mounting posture of the alignment scope to the original state because there is no reference.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an alignment scope position calibration apparatus which can easily and accurately calibrate the position of an alignment scope by using a reference mask. It is intended to provide such a method.

[0008]

The present invention has the following configuration in order to achieve the above object. That is, the alignment scope position calibration device according to claim 1 performs an alignment scope measurement of the processing target object before performing a predetermined process in the processing unit on the processing target object mounted on the mounting table. In the apparatus for calibrating the position of the above, the mounting table is provided with a reference mask in which a two-dimensional reference pattern is formed in a movable range of the alignment scope, and the alignment scope is provided with a reference pattern of a predetermined position formed in the reference mask. After the movement of the alignment scope, the position of the alignment scope is calibrated based on the amount of displacement between the reference pattern at the predetermined position and the alignment scope.

According to a second aspect of the present invention, there is provided an alignment scope position calibrating apparatus according to the first aspect, wherein the reference mask comprises:
It is characterized by being disposed below a processing target placed on the mounting table.

According to a third aspect of the present invention, there is provided an alignment scope position calibrating device according to the second aspect, further comprising an elevating mechanism for elevating the reference mask in the optical axis direction of the alignment scope. In addition, the apparatus is characterized in that the reference mask is moved so as to be away from the focus of the alignment scope at the time of measurement by the alignment scope on the processing object.

According to a fourth aspect of the present invention, in the method for calibrating the position of the alignment scope, the measurement of the processing target object is performed before the processing unit performs predetermined processing on the processing target object mounted on the mounting table. In the method of calibrating the position of the alignment scope to be performed, a step of disposing a reference mask on which a two-dimensional reference pattern is formed on the upper or lower part of the mounting table in a movable range of the alignment scope,
Moving the alignment scope to a reference pattern at a predetermined position formed on the reference mask, and calibrating the position of the alignment scope based on the amount of displacement between the alignment pattern and the reference pattern at the predetermined position formed on the reference mask. And performing the steps sequentially.

[0012]

The operation of the first aspect of the present invention is as follows. Prior to the processing, the alignment scope is moved to a reference pattern at a predetermined position of a reference mask provided on the mounting table, and then the amount of displacement between the reference pattern and the alignment scope is obtained, and the position is calibrated based thereon.

For example, the "position shift amount" between the reference pattern at a predetermined position and the center of the optical system of the alignment scope is obtained by image processing, and the difference (the distance in the moving direction of the drawing stage and the distance in the direction orthogonal thereto) is calculated. Find and memorize. As a result, the "position shift amount" of the alignment scope can be determined, so that the position where the alignment scope is actually moved when the alignment scope is moved can be accurately determined based on the reference mask of the mounting table.

According to the second aspect of the present invention, since the reference mask is disposed below the processing object mounted on the mounting table, the reference mask is removed when the processing object is replaced. No need.

According to the third aspect of the present invention, when measuring the object to be processed by the alignment scope, the reference mask is moved away from the focal position by the elevating mechanism, thereby making it possible to measure the object to be processed. Measurement of the reference pattern of the reference mask during subsequent processing can be prevented.

According to a fourth aspect of the present invention, prior to the processing, the alignment scope is moved to a reference pattern at a predetermined position of a reference mask provided on the lower or upper part of the mounting table, and the reference pattern and the reference pattern are moved. The position is calibrated based on the amount of displacement from the alignment scope.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view for explaining the outline of a printed circuit board manufacturing apparatus provided with an alignment scope position calibrating apparatus according to the present invention, FIG. 2 is a detailed plan view, and FIG. 3 is a detailed side view.

On the upper surface of the base 1, a pair of linear guides 3
Are arranged, and between those linear guides 3,
A feed screw 9 driven to rotate by a servomotor 7 is provided. The drawing stage 5 is screwed to the feed screw 9 at its lower part. The drawing stage 5 includes a rotating mechanism 11 for rotating the mounting table 15 around a vertical z-axis and an elevating mechanism 13 for raising and lowering the mounting table 15 in the vertical z-direction, from the bottom. . The mounting table 15 is for mounting the printed circuit board S (processing object) on the top.

A mounting table 1 corresponding to the mounting table of the present invention
5 is configured as shown in the sectional view of FIG. That is, the reference mask RM is provided on the upper surface of the base 15a of the mounting table 15, and the suction table 17 is provided thereon. Although a grid-like reference pattern PR is formed on the entire upper surface of the reference mask RM as shown in FIG. 5, it may be formed only in a movable range of an alignment scope described later. Reference mask RM
The upper reference pattern PR has, for example, a line width of 50 μm and a width of 5 μm.
It is formed at mm intervals.

On the upper surface of the suction table 17, a suction groove 17a is provided at a position which does not overlap with the lower reference pattern PR in plan view.
Is pierced. A vacuum suction source (not shown) is connected to the suction groove 17a, and sucks and holds the lower surface of the printed circuit board S mounted on the upper surface through the suction groove 17a. In this embodiment, the above-described reference mask RM and the suction table 17 are both formed of transparent glass.
Irradiation light from a backlight (not shown) incorporated in the lowermost base 15a is applied to the printed circuit board S so that the reference hole SR emerges.

In the y-direction (sub-scanning direction) in which the drawing stage 5 is moved by the drive of the servomotor 7, the processing position E
A processing unit 21 is provided which irradiates the laser beam LB for drawing with P downward while deflecting it in the x direction (main scanning direction). The processing unit 21 is disposed above the base 1 with a gate-shaped frame, and the drawing stage 5 moves forward and backward with respect to the processing unit 21 when the servo motor 7 is driven.

As shown in FIG. 3, the lifting mechanism 13 is
5a, a slant member 13a having a slanted upper surface, a screw shaft 13b with which the screw member 13a is screwed, and a screw shaft 1b.
And a pulse motor 13c for rotatingly driving the motor 3b. The free wheel attached to the lower surface of the base 15a,
By driving the pulse motor 13c, the ascending and descending surfaces of the inclined member 13a which moves forward and backward in the y direction are moved up and down in the z direction along guide rails (not shown).

As shown in FIGS. 2 and 3, the base 1 is provided with an alignment scope unit 31 so as to cover above the drawing stage 5 at the standby position. The alignment scope unit 31 includes four alignment scopes 33 and 3 that can move independently in a horizontal plane.
5, 37 and 39 are provided. Each of the alignment scopes 33, 35, 37, 39 is a CCD camera 33a, 35
a, 37a, 39a and lens portions 33b, 35b, 37
b, 39b.

The alignment scope unit 31 has a scope stage 41 erected on the base 1, and a left stage 43 on which alignment scopes 33 and 39 are mounted and a right stage 45 on which alignment scopes 35 and 37 are mounted. And The left stage 43
Linear guide 41 disposed on scope stage 41
a is slidably fitted in the x direction and is screwed to a feed screw 41c rotated by a pulse motor 41b. A linear guide 43a is disposed in the upper part in the y direction, and a moving block 43b to which the alignment scope 39 is attached is fitted to the linear guide 43a. The moving block 43b is screwed to a feed screw 43d rotated by a pulse motor 43c. Therefore, when the pulse motor 41b is driven, the alignment scopes 33 and 39 are moved together with the left stage 43 in the x direction. When the pulse motor 43c is driven, the alignment scope 33 fixed to the linear guide 43a is moved. Does not move, only alignment scope 39 is y
It is to be moved in the direction.

The right stage 45 is the scope stage 41
It is slidably mounted in the x direction with respect to the linear guide 41a provided thereon, and is screwed to a feed screw 41e rotated by a pulse motor 41d. A linear guide 45a is provided on the upper part, and a moving block 45b to which the alignment scope 37 is attached is mounted on the linear guide 45a. The moving block 45b includes a pulse motor 45.
It is screwed with the feed screw 45d rotated by c. Therefore, when the pulse motor 41d is driven,
When the alignment scopes 35 and 37 are moved in the x-direction together with the right stage 45, when the pulse motor 45c is driven, only the alignment scope 37 is alone y.
Moved in the direction.

Referring to the block diagram of FIG. CCD camera 3 for each alignment scope 33, 35, 37, 39
3a, 35a, 37a, and 39a are all connected to the image processing unit 49, where each video signal is processed to calculate the position of the center of gravity and to calculate the "position shift amount". In addition, the image processing unit 49 includes a keyboard 51 for instructing the start of processing and the like, the alignment scopes 33 and 35,
A CRT 53 for displaying images captured by 37 and 39 and displaying processing contents is connected.

The system control unit 55 controls the entire apparatus. Here, the main scanning control circuit 57
, A sub-scanning control circuit 59, a calibration data storage unit 61, and the like.

At the time of drawing, the system control section 55 sets a main scanning control circuit 57 for setting the position of the laser beam LB in the x direction based on the raster data sequentially sent from the raster conversion circuit 63 to the main scanning control circuit 57. Control.
The main scanning control circuit 57 controls the electronic shutter based on an instruction from the system control unit 55 and the raster data. Further, an optical signal from an X linear scale (not shown) arranged in the x direction is detected, and the deflection distance of the laser beam LB in the main scanning direction is measured. The signal from here is appropriately processed before being taken into the system control unit 55, and a clock pulse for the sub-scanning control circuit 59 is generated based on this signal.

The sub-scanning control circuit 59 outputs the laser beam LB
The servo motor 7 is driven based on the clock pulse generated in accordance with the main scanning of FIG. This makes the drawing stage 5
Is moved in the y direction (sub-scanning direction). The moving position is detected by a sensor that detects an optical signal from a Y linear scale (not shown), converted into a signal corresponding to the moving position, and provided to the system control unit 55. The system control unit 55 feeds back the drive of the servomotor 7 according to the signal.

The calibration data storage unit 61 stores a reference mask RM.
When the drawing stage 5 provided below the suction table 17 is moved to the standby position, the image processing unit 49 processes the video signals from the two alignment scopes 33 and 35 provided on the processing unit 21 side. This stores the “position shift amount” between the center position of each alignment scope 33 and 35 and the reference pattern PR.

The "position shift amount" will be described more specifically with reference to FIG. For example, alignment scope 3
Center of the visual field image V captured by the third CCD camera 33a
And the deviation from the intersection of the reference pattern PR at the predetermined position are determined for the x direction (Δx) and the y direction (Δy). If the “position shift amount” at this time is “0” in both the xy directions, the intersection of the reference pattern PR and the visual field center C in FIG.
Will match. The above-described calibration data storage unit 6
1 stores the above Δx and Δy. That is, even when the position of the alignment scope 33 is displaced for some reason, the amount of displacement from the position is stored with reference to the reference pattern PR of the reference mask RM, which is design-invariant. Therefore, this "position shift amount"
Is read and corrected by that amount, the actual position at the field center C of the alignment scope 33 can be accurately determined.

Each of the alignment scopes 33, 3
The drive units 65, 37, and 39 are provided for each of the alignment scopes 33, 35, 37, and 39, but only the pulse motors are different. . The drive section 65 includes a drive circuit 65a that controls the pulse motor 41b based on an instruction from the system control section 55.
Note that, in FIG. 6, blocks other than the alignment scope 33 are not illustrated for the drive units.

The elevation control circuit 67 controls the elevation of the mounting table 15 in the z direction. System control unit 5
Reference numeral 5 controls the rotation of the pulse motor 13c via the drive circuit 69 in accordance with the processing as described later. Pulse motor 1
The mounting table 15 is moved up and down by the driving of 3c. The height at this time is detected by a height detecting circuit 73 including a Z linear scale (not shown), and is fed back to the system control unit 55.

Next, the position calibration processing in the apparatus of this embodiment will be described with reference to the flowchart of FIG.

Step S1 The system controller 55 sets the printed circuit board S to be processed.
Is read from a computer (not shown).

Step S2 The system controller 55 moves the alignment scopes 33, 35, 37, 39 to the positions based on the position data of the reference holes SR of the printed circuit board S in the received CAD data (coarse position adjustment). ).

That is, the alignment scopes 33, 3
When the printed circuit board S is mounted on the mounting table 15 by controlling the driving units 65 corresponding to 5, 37, and 39, the alignment scopes 33, 35, 37, and 39 are controlled by the reference holes SR (normally). (Formed at the four corners of the substrate). In addition, only the drive circuit 65 of the alignment scopes 33, 35, 37, and 39 has the alignment scopes 33, 35, and 35 near the reference hole SR.
If it is not possible to move 37 and 39, the servo motor 7 may be driven via the sub-scanning control circuit 59 to move the mounting table 15.

More specifically, a required pulse is given to the pulse motor 41b via the drive circuit 65a of the alignment scope 33 to move the alignment scopes 33 and 39 toward the feed screw 9 side. A required pulse is given to the pulse motor 43c via the 65a, the alignment scope 39 is moved to the processing position EP side, and a required pulse is given to the pulse motor 41d via the drive circuit 65a of the alignment scope 35, so that the feed screw 9 is provided. The alignment scopes 35 and 37 are moved toward
7, a required pulse is given to the pulse motor 45c via the drive circuit 65a of FIG.
7 is moved. Thereby, the alignment scope 3
In each of the fields of view 3, 35, 37, and 39, the intersection of the reference pattern PR at a predetermined position of the reference mask RM is located although it is out of focus.

Step S3: The mounting table 15 is raised in the z direction via the lifting control circuit 67, and the alignment scopes 33, 35, 37, 3
9 is focused on a reference pattern PR at a predetermined position.

Step S4 Image processing is performed on the visual field image V of each of the alignment scopes 33, 35, 37, and 39, and a difference between the visual field center C and the intersection of the reference pattern PR is obtained (see FIG. 7).

Step S5 The difference (Δx, Δy) obtained in the above step S4
Is stored in the calibration data storage unit 61 as the “position shift amount” of each of the alignment scopes 33, 35, 37, and 39. Here, if the "position shift amount" is stored in the calibration data storage unit 61, when the alignment scopes 33, 35, 37, and 39 are moved in the subsequent processing, it is calculated from the number of pulses given to the pulse motor. The position of the center of the field of view is shifted from the position by the “position shift amount” and handled as an actual position.

Step S5 corresponds to the process of performing the position calibration of the present invention.

Step S6 The mounting table 15 raised in step S3 is
The alignment scopes 33, 35, 37, and 39 are lowered to standby positions so as to be away from the focal positions. This allows the alignment scope 33,
It is possible to prevent the inconvenience that the measurement is performed erroneously on the reference pattern PR instead of the printed circuit board S.

As described above, the alignment scope 3
After finishing the position calibration processes of 3, 35, 37, and 39, for example, the process for the printed circuit board S is performed as follows.

That is, the printed circuit board S is mounted on the mounting table 15 by a loader (not shown), and the substrate S is suction-held by vacuum suction. Each of the alignment scopes 33, 35, 37, and 39 moves above the reference holes SR formed at the four corners based on the CAD data of the substrate S. The positions of the reference holes SR at the four corners are measured by image processing, and the mounting position of the printed circuit board S is measured by obtaining their centers of gravity. At this time, the “position shift amount” stored in the calibration data storage unit 61 is obtained. Is read out,
The position of the center of the visual field of each alignment scope 33, 35, 37, 39 is corrected. The posture is measured in this manner, and the mounting table 15 is rotated in the θ direction in accordance with the posture to be parallel to the laser beam LB. Then, the drawing process is performed at the processing position EP while moving toward the processing unit 21. Apply.

As described above, according to the apparatus of the present embodiment, the reference mask RM of the mounting table 15 is
When the alignment scopes 33, 35, 37, and 39 are moved, it is possible to know exactly where they are actually located. Therefore, unlike the conventional example, there is no need to provide a length measuring device such as a linear scale, and the position of the alignment scopes 33, 35, 37, and 39 can be easily and highly accurately calibrated with a relatively simple configuration. .

The present invention can be modified as follows.

(1) Place the reference mask RM on the mounting table 15
Instead of being fixed at the position, it may be detachable. That is, the position calibration process described above may be performed with the reference mask RM attached to the mounting table 15 prior to the process, and the reference mask RM may be removed before processing the substrate.

(2) The reference pattern formed on the reference mask RM is not limited to the above-described lattice shape, and may have any shape as long as a specific position of the pattern is obtained.

(3) In the above description, the mounting table 15 is lowered after the position calibration processing. However, if there is no inconvenience in the subsequent processing, it is not necessary to lower the mounting table 15.

The electronic aperture provided in the CCD camera may be opened so as to focus only on the vicinity of the printed circuit board S without lowering the mounting table 15, so as to reduce the depth of the subject.

(4) The number of alignment scopes is not limited to four as in the embodiment, and the present invention can be applied to at least one alignment scope.

However, when there is only one alignment scope, the position calibration process is performed with the printed circuit board mounted on the mounting table 15. Then, the alignment scope is sequentially moved to the reference holes at the four corners to measure the amount of displacement between the center of the visual field and the intersection of the reference pattern PR at each position, and at the same time, the center of gravity of the reference hole SR is obtained to determine the intersection of the reference pattern PR. It is necessary to obtain a relative position error with respect to the above.

(5) In the above embodiment, the printed circuit board manufacturing apparatus has been described as an example. However, the present invention can be applied to any apparatus that performs processing such as measurement using an alignment scope. For example, the present invention can be applied to a PDP substrate manufacturing device, a precision measuring device, and the like.

[0055]

As is apparent from the above description, according to the first aspect of the present invention, when the alignment scope is moved by using the reference mask of the mounting table as a position reference, Is exactly known. Therefore,
There is no need to provide a length measuring device such as a linear scale, and the position of the alignment scope can be easily and highly accurately calibrated with a relatively simple configuration.

According to the second aspect of the present invention, since the reference mask is disposed below the processing object mounted on the mounting table, the reference mask is removed when the processing object is replaced. There is no need to perform the processing on the processing object efficiently while calibrating the position of the alignment scope.

According to the third aspect of the present invention, it is possible to prevent the reference mask from being measured by moving the reference mask away from the focal position of the alignment scope by the elevating mechanism. Can be prevented from being provided below the processing target of the mounting table.

According to the fourth aspect of the present invention, the position calibration is performed by moving the alignment scope to the reference pattern at a predetermined position of the reference mask prior to the processing, so that the position calibration can be performed easily and with high accuracy. Can be implemented.

[Brief description of the drawings]

FIG. 1 is a perspective view for providing a brief description of a printed circuit board manufacturing apparatus provided with an alignment scope position calibrating apparatus according to the present invention.

FIG. 2 is a detailed plan view of the printed circuit board manufacturing apparatus.

FIG. 3 is a detailed side view of the printed circuit board manufacturing apparatus.

FIG. 4 is a sectional view of a mounting table.

FIG. 5 is a plan view of a mounting table.

FIG. 6 is a block diagram of a printed circuit board manufacturing apparatus.

FIG. 7 is a schematic diagram showing a visual field image of a CCD camera.

FIG. 8 is a flowchart showing a position calibration process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base 3 ... Linear guide 5 ... Drawing stage 7 ... Servo motor 9 ... Feed screw 11 ... Rotation mechanism 13 ... Elevating mechanism 15 ... Mounting table (mounting table) 17 ... Suction table RM ... Reference mask PR ... Reference pattern S … Printed circuit board (object to be processed) 21… processing part LB… laser beam 33, 35, 37, 39… alignment scope 41… scope stage

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroyuki Shirota 4-chome Tenjin Kitamachi 1-chome, Horikawa-dori-Terauchi, Kamigyo-ku, Kyoto F-term (reference) 2F065 AA03 CC00 FF01 FF04 JJ03 JJ26 PP12 QQ31 RR03 2H097 KA13 KA28 LA09

Claims (4)

[Claims] 1. An apparatus for calibrating a position of an alignment scope for measuring a processing target object before performing a predetermined processing on a processing target object mounted on a mounting table by a processing unit. The mounting table includes a reference mask in which a two-dimensional reference pattern is formed in a movable range, and after moving an alignment scope to a reference pattern in a predetermined position formed in the reference mask, the reference pattern in the predetermined position A position calibration device for an alignment scope, wherein the position of the alignment scope is calibrated based on the amount of displacement between the alignment scope and the alignment scope. 2. The alignment scope according to claim 1, wherein the reference mask is disposed below a processing object mounted on the mounting table. Position calibration device. 3. The position correcting apparatus for an alignment scope according to claim 2, further comprising an elevating mechanism for elevating and lowering the reference mask in a direction of an optical axis of the alignment scope. A position calibration device for an alignment scope, wherein the reference mask is moved away from the focal point of the alignment scope. 4. A method for calibrating the position of an alignment scope for measuring a processing object prior to performing a predetermined process on a processing object mounted on a mounting table by a processing unit, the method comprising: Disposing a reference mask on which a reference pattern is formed on the upper or lower part of the mounting table in a range in which the alignment scope can move; and moving the alignment scope to a reference pattern at a predetermined position formed on the reference mask. A step of calibrating the position of the alignment scope based on the amount of misalignment between the alignment scope and a reference pattern at a predetermined position formed on the reference mask.