KR100924210B1 - Apparatus for inspecting pattern of film work - Google Patents

Abstract

In the pattern inspection apparatus of the film workpiece which scans an imaging unit in the width direction of a long film workpiece, acquires the image of the pattern formed in the workpiece, and performs inspection, even if the curvature of the width direction arises in a film workpiece, An apparatus is provided so as to scan a unit so that a focal position does not shift along a curvature and acquire a pattern image without blurring.

In the vicinity of the imaging unit, a distance sensor for measuring the distance to the workpiece surface is provided, and when the imaging unit is scanned in the width direction of the workpiece, the imaging unit is moved from the distance sensor to the film work based on the distance information. Move the distance to be the focal length. You may move a film workpiece.

Description

Pattern inspection apparatus of film work {APPARATUS FOR INSPECTING PATTERN OF FILM WORK}

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the pattern inspection apparatus of the film work which is an Example of this invention.

Fig. 2 is a diagram showing the detailed configuration of the inspection section of the pattern inspection apparatus (first embodiment).

3 is a view for explaining the operation of the imaging unit in the first embodiment.

Fig. 4 is a diagram showing the detailed configuration of the inspection section of the pattern inspection apparatus (second embodiment).

5 is a view for explaining the operation of the imaging unit in the second embodiment.

Fig. 6 is a diagram showing the detailed configuration of the inspection section of the pattern inspection apparatus (third embodiment).

7 is a diagram (1) illustrating the operation of the imaging unit in the third embodiment.

8 is a diagram for explaining the operation of the imaging unit in the third embodiment (No. 2).

9 is a diagram showing the detailed configuration of the inspection section of the pattern inspection apparatus (fourth embodiment).

<Description of the symbols for the main parts of the drawings>

10: film work conveyance mechanism

11: delivery reel

12: reel reel

21: reflective lighting means

22: transmission lighting means

3: marker part

4: control unit

5: inspection unit

51: imaging unit

52: CCD line sensor

53: lens unit

54: imaging unit holder

55: scan moving motor

56: rail

57: optical axis moving motor

58: shaft

59: distance sensor

61, 62: prop

71: conveying roller

72: brake roller

80: injection means

90: work edge holding mechanism

91: plate

92: plate moving mechanism

F: focal length of the imaging unit

W: Film Walk

L: optical axis of the imaging unit

The present invention relates to an inspection apparatus for a film work that automatically inspects a pattern formed on a long film work such as a TAB tape or an FPC (flexible printed circuit board).

In particular, when the film work is loosened (curved) in the width direction, it is related with the inspection apparatus of the film workpiece which picks up and performs automatic inspection, performing autofocus (autofocus).

By visually inspecting a pattern of a circuit or the like formed on a long film work (hereinafter referred to as a work) such as a TAB tape or an FPC (Flexible Printed Substrate), an image of the pattern is captured by an imaging device such as a CCD. Background Art A pattern inspection apparatus is known which determines the quality of a product in comparison with a master pattern acquired in advance.

In Patent Document 1, in the inspection apparatus for a film work as described above, a CCD line sensor for acquiring image data is arranged in the longitudinal direction of the film work in response to a change in the width of the film work being widened. The device which scans in the width direction of a film workpiece, and acquires an image is shown.

However, the film work as described above is warped in the width direction by treatment in a process such as exposure phenomenon or etching for forming a pattern, and also loosens due to its own weight. In this case, the shape is not flat but curved.

In the case of inspecting such curved film workpieces using the above-described apparatus, the surface of the workpiece is shifted from the focal position of the imaging element during scanning only by simply scanning the imaging element in the width direction of the workpiece. The image of the acquired pattern is blurred and cannot be inspected.

When the back surface of the field work is absorbed by the planar stage, the curved shape of the work is corrected, and the above problem can be solved. However, when the stage is used, it is difficult to inspect the light by the transmitted illumination light which irradiates the illumination light from the back side of the work and acquires an image of the pattern by the light transmitted through the work, or the scratch may occur on the back side of the work. In some cases, it is necessary to inspect without using a stage.

Therefore, as in Patent Document 2 or Patent Document 3, the film workpiece is held at the focal position of the imaging device by mechanically holding the edge in the width direction of the film work, applying tension to correct the curvature of the work, and keeping the surface flat. It is proposed to keep as.

However, film workpieces such as TAB tapes and FPCs are getting wider and thinner every year. When the width is thin and thin, only the edges of the workpiece are tensioned and the curvature of the film workpiece may not be completely eliminated, and it may not be maintained at the focal position of the imaging device.

In patent document 4, when examining the film workpiece which shows a curved shape in the width direction as mentioned above, scanning the line sensor which is an imaging element in the width direction of a film workpiece twice in the same location, and obtaining an image is mentioned. Is shown.

That is, based on the detection signal of the line sensor acquired by the 1st drive scan, the distance from a film work to a line sensor is calculated | required continuously, and in a 2nd drive scan, it is a film based on the distance data obtained by the 1st drive scan. A drive scan of the line sensor is performed along the curvature of the workpiece to obtain a pattern image without blurring.

However, in the case where the line sensor is scanned twice in one inspection, the inspection processing takes a long time and the throughput decreases.

This invention is made | formed in view of the said situation, The objective is the pattern inspection apparatus of the film work which scans an image pick-up element in the width direction of a long film workpiece, and acquires the image of a pattern, WHEREIN: Scanning only once of an image pick-up element is carried out. It is an object of the present invention to provide an apparatus capable of acquiring a pattern image without blurring.

(Patent Document 1) Japanese Patent Application Laid-Open No. 2001-160571

(Patent Document 2) Japanese Patent Application Laid-Open No. 2004-28597

(Patent Document 3) Japanese Patent Application Laid-Open No. 2002-217249

(Patent Document 4) Japanese Patent Application Laid-Open No. 2002-372503

In this invention, the said subject is solved as follows.

In the pattern inspection apparatus of the film workpiece which scans an imaging unit in the width direction of a elongate film workpiece | work, and acquires and examines the image of the pattern formed on this film workpiece, it moves an imaging unit or a film workpiece to the optical axis direction of an imaging unit. An optical axis direction moving mechanism is installed.

Moreover, while providing the distance sensor which measures the distance to a film workpiece in the vicinity of an imaging unit, and measuring the distance to a film workpiece, it moves to the width direction of a film workpiece with an imaging unit.

The apparatus control unit moves the imaging unit or the film work in the optical axis direction of the imaging unit by the optical axis direction moving mechanism based on the distance information to the film work measured by the distance sensor, and focuses on the curved film work. Keep it in position.

The position at which the distance sensor is provided may be a position extending in the longitudinal direction of the CCD line sensor arranged along the longitudinal direction of the film work which is the imaging element, and the imaging unit scans as a direction perpendicular to the longitudinal direction of the CCD line sensor. It may be a forward direction.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the pattern inspection apparatus of the film work which is an Example of this invention.

The pattern inspection apparatus (henceforth a pattern inspection apparatus) of the film workpiece | work of this embodiment is equipped with the film workpiece conveyance mechanism 10, and the film workpiece | work W (hereafter also called a workpiece | work), such as TAB tape and FPC in which the pattern was formed. ) Is unwound from the delivery reel 11 of the tape conveyance mechanism 10 and wound around the winding reel 12.

In the vicinity of the winding reel 12, the marker part 3 which attaches a mark to a defective pattern is provided. In the marker part 3, markers, such as perforation and coloring by a punch, are written on the pattern judged to be defective, and visually confirm that the part is defective.

The film work W sent out from the delivery reel 11 is sent to the inspection part 5. The conveyance roller 71 is provided in the conveyance downstream of the test | inspection part 5, The brake roller 72 is provided in the conveyance upstream of the test | inspection part 5, and the film workpiece W is tensioned in the longitudinal direction, It is conveyed intermittently.

The inspection unit 5 is provided with an imaging unit 51 for imaging a pattern such as a circuit formed on the workpiece W by the reflective illumination means 21 and the illumination light reflected by the film workpiece W. As shown in FIG.

Moreover, the illuminating means may be provided on the opposite side to the imaging unit 51 with respect to the film work W, and may be set as the transmissive illuminating means 22 (shown with the dotted line in drawing). In this case, the imaging unit 51 images the pattern of the circuit etc. which are formed in the workpiece | work W by the illumination light which permeate | transmitted the film workpiece W. As shown in FIG.

The scanning means 80 is attached to the imaging unit 51, and the scanning means moves the imaging unit 51 and the reflective illuminating means 21 to the width of the workpiece W on the inspection pattern of the film work W. FIG. It moves to the direction (similar to FIG. Front inside), and the image of the whole inspection area | region (the area | region in which the pattern is formed) of the film workpiece W is obtained.

 In addition, the structure of this scanning means 80 and the detailed operation | movement when the imaging unit 51 acquires an image are mentioned later.

 In addition, when the pattern image is acquired by the imaging unit 51, the test | inspection part 5 hold | maintains the both ends (edge) of the width direction of the film workpiece W, and pulls the workpiece | work W in the width direction, The work edge holding mechanism 90 which applies tension and reduces loosening is also provided.

The control part 4 of an apparatus image-processes the image pattern picked up by the imaging unit 51, and determines the quality of a product compared with the master pattern used as the reference | standard of the test memorize | stored beforehand. Moreover, the operation | movement of the whole pattern inspection apparatus, such as the inspection part 5, the marker part 3, and the tape conveyance mechanism 10, is controlled.

FIG. 2 is a diagram showing a detailed configuration of an inspection unit of the pattern inspection apparatus of FIG. 1, and a first embodiment of the present invention will be described with reference to the drawing. In addition, the reflective illuminating means 21 and the workpiece | work holding mechanism 90 are abbreviate | omitted and shown in figure.

FIG. 2 (a) is a plan view of the inspection portion viewed in a direction orthogonal to the surface on which the film work is conveyed, FIG. 2 (b) is a view seen from the conveying direction of the film work, and FIG. 2 (c) is a width direction of the film work. This is the figure.

51 is an imaging unit, The imaging unit 51 is an optical element (single or plural) which forms the pattern on the film work W on the CCD line sensor 52 which is an imaging element, and the CCD line sensor 52. Lens unit 53).

As shown to Fig.2 (a), the CCD line sensor 52 is provided so that the longitudinal direction may be parallel to the longitudinal direction of the film workpiece W, ie, parallel to the conveyance direction of the film workpiece W. As shown to FIG. .

In addition, as shown in FIG.2 (b) (c), the imaging unit 51 has the width | variety of the film work W so that the positional relationship of the CCD line sensor 52 and the lens unit 53 may not change. It is comprised so that it may move independently to a direction (X direction) and the optical axis L direction (Z direction) of the imaging unit 51, respectively.

The optical axis L of the imaging unit 51 is a virtual straight line which connected the center of the CCD line sensor 32 provided in the imaging unit 51, and the center of the optical element arrange | positioned in the lens unit 53, and is a film workpiece It is orthogonal to the conveyance plane of (W).

The imaging unit 51 is attached to the imaging unit holder 54 via the shaft 58 which is a stretchable material, and is arranged in the optical axis L direction by the optical axis direction moving motor 57 provided in the imaging unit holder 54. Move to (Z direction). Thereby, the imaging unit 51 approaches or spaces apart from the film work W. As shown in FIG.

In addition, the imaging unit support 54 moves along the rail 56 by the scan movement motor 55.

The rail 56 extends and is set in the direction orthogonal to the conveyance direction of the film work W, and thus the imaging unit 51 moves by the imaging unit holder 54 moving along the rail 56. Scanning movement in the width direction (X direction) of the film work (W).

In addition, a distance sensor 59 is mounted on the lens unit 53 of the imaging unit 51, the distance to the surface of the film work W is measured, and the measured distance data to the film work W is Is sent to the control unit 4 of the apparatus.

The distance sensor 59 uses the commercially available side length measuring instrument which reflects the red light of wavelength 700nm to an object, and measures a distance.

The reason why the output of light of this wavelength is used as the distance sensor is because polyimide is well used as the material of the resin used for the TAB tape and the FPC, and the polyimide efficiently reflects red light having a long wavelength.

In the first embodiment, the distance sensor 59 is mounted at a position that is a longitudinal extension of the CCD line sensor 52 of the lens unit 53 of the imaging unit 51.

Therefore, the position where the distance sensor 59 measures the distance to the film work W becomes an extended position of the longitudinal direction of the film work W with respect to the position imaged by the CCD line sensor 52. .

The distance sensor 59 moves with the imaging unit 51 when the imaging unit 51 moves to the width direction (X direction) of the workpiece | work and the optical axis L direction (Z direction).

FIG. 3 is a view for explaining the operation of the imaging unit in the first embodiment, and similarly to FIG. 2B, the imaging unit is viewed from the conveyance direction of the film work.

An operation of controlling the imaging unit at the focal length with respect to the film work at the time of pattern imaging will be described using the same drawing.

Prior to performing the pattern inspection of the film work W, as a preparation, the relationship between the focal position of the imaging unit 51 and the distance to the surface of the film work W by the distance sensor 59 is as follows. Get it.

In the direction of the optical axis L of the imaging unit 51, a flat plate on which a test pattern is formed is placed, and the test pattern is focused on the CCD line sensor 52 by focusing on the test pattern.

In that case, the distance to the surface of the film work W is measured by the distance sensor 59, this is made into the focal length F, and the focal length F is memorize | stored in the control part 4 of an apparatus.

In this case, the distance to be measured is the distance from the distance sensor 59 to the surface of the workpiece W, and in an optically exact sense, it is different from the focal length of the optical element of the lens unit 53 of the imaging unit 51. In the present invention, the distance from the distance sensor 59 measured by the distance sensor 59 to the surface of the workpiece W at the position where the pattern is formed on the CCD line sensor 52 of the imaging unit 51 is measured. To define the focal length.

Apart from this, the master pattern serving as the inspection standard is also stored in the control unit.

After the above preparation is completed, inspection of the pattern is started. The film work W which inspects is wound by a delivery reel, and is installed in the pattern inspection apparatus shown in FIG.

As mentioned above, the film workpiece W is conveyed and the part which inspects stops in the inspection part 5 of an apparatus.

As shown to Fig.3 (a), with respect to the film workpiece W conveyed to the test | inspection part 5, the distance sensor 59 measures the distance to the surface of the film workpiece W, and measured distance The data of A is sent to the controller 4 of the apparatus.

 The control part 4 compares the measured distance A with the focal length F memorize | stored above, computes the difference A-F, and moves the imaging unit 51 to the optical axis L direction by the distance of this difference A-F. The optical axis direction moving motor 57 is driven so as to descend.

Thereby, as shown in FIG.3 (b), the imaging unit 51 descends by the distance A-F along the optical axis L direction to the direction (Z direction) which approaches the film work W. As shown to FIG.

Since the distance sensor 59 is attached to the lens unit 53 of the imaging unit 51, the distance A-F is lowered together with the imaging unit 51.

 The distance sensor 59 repeats the measurement of the distance to the film work W at a specific short period, and continues to send the distance data to the control part 4.

The control unit 4 lowers the imaging unit 51 until the distance A-F becomes zero.

When the imaging unit 51 reaches the focal length F, the difference between the measurement distance data A and the focal length F disappears, so that the control unit 4 stops the driving of the optical axis direction moving motor 57 and the imaging unit 51 Is maintained at the focal length F.

The pattern formed in the film work W on the CCD line sensor 52 forms an image. The CCD line sensor 52 acquires this formed pattern image and sends it to the control part 4, The control part 4 image-processes and stores this.

Next, the scan movement motor 55 is driven, and the imaging unit 51 and the distance sensor 59 are scanned in the width direction (X direction) of the film work W together with the imaging unit holder 54. .

The imaging unit 51 acquires the pattern image of the film work W by the CCD line sensor 52 while scanning, and the distance sensor 59 measures the distance to the film work W. As shown in FIG.

If the film work W is loosened in the curved shape with respect to the width direction, as the imaging unit 51 is scanned, it will again to the film work W measured by the distance sensor 59 as shown in FIG.3 (a). The distance A becomes longer.

The control unit compares the measured distance A with the focal length F, calculates the difference A-F, and again, as shown in FIG. 3 (b), the imaging unit 51 moves the optical axis L direction (Z) by this difference A-F. Direction, the optical axis direction movement motor 57 is driven, and the position of the imaging unit 51 is maintained at the focal length F.

As a result, the CCD line sensor 32 can always acquire a pattern image without blurring of an image.

The looseness of the film work W is considered to be the most loose in the vicinity of the center portion with respect to the workpiece width direction. When the scanning of the imaging unit 51 passes through the center portion of the workpiece width direction, this time by the distance sensor 59. The distance A to the film work W to be measured becomes short.

In that case, the control part 4 raises the imaging unit 51 to the optical axis L direction (Z direction) by the measured distance A and focal length F difference A-F minutes, and focuses the position of the imaging unit 51. Keep at distance F.

In this way, the imaging unit 51 scans the inspection area in the width direction of the film work W, and the CCD line sensor 32 acquires image data without blurring of the pattern, and the data is controlled by the control unit 4. Is sent).

The control part 4 image-processes the image data sent after the scanning movement of the imaging unit 51 is completed, and compares it with the master pattern memorize | stored, and judges a good or bad.

In the case of this embodiment, the position where the distance is measured by the distance sensor 59 and the position where the CCD line sensor 32 acquires an image differ with respect to the longitudinal direction of the film work W. FIG.

However, the distance sensor 59 is attached to the lens unit 53 of the imaging unit 51, and corresponds to the position immediately next to the longitudinal direction of the CCD line sensor 32, and also the curvature of the film work W. FIG. The amount of is considered to be not significantly different with respect to the longitudinal direction of the workpiece.

Therefore, even if the distance of the imaging unit 51 is adjusted based on the distance to the workpiece | work W measured at this position, the CCD line sensor 32 can acquire the image of the pattern in which the focus is not blurred.

Fig. 4 is a diagram showing the configuration of the second embodiment of the inspection section of the pattern inspection apparatus, and the second embodiment of the present invention will be described using the same drawing.

In addition, like the case of FIG. 2, the reflective illuminating means 21 is abbreviate | omitted, and is shown with the same code | symbol about the structure similar to FIG.

In this embodiment, the distance at which the image is acquired by the CCD line sensor can be measured by the distance sensor.

The distance sensor 59 is different from the first embodiment, is supported on the imaging unit holder 54 by a support 61, and is independent of the imaging unit 51.

Accordingly, the distance sensor 59 is scanned by the imaging unit holder 54 in the width direction (X direction) of the film work W together with the imaging unit 51, but the optical axis L direction (Z direction). ) Does not move.

The distance sensor 59 is a direction orthogonal to the longitudinal direction of the CCD line sensor 32, and is provided in the front direction (the front of the X direction) in which the imaging unit 51 is scanned and moved, and the workpiece W surface at the position. Measure the distance to.

From the position where the distance sensor 59 measures the distance to the film work W (sensor position) to the position where the pattern image is acquired by the CCD line sensor 32 (optical axis L of the imaging unit 52). The space | interval B is measured and measured at the time of manufacturing a pattern inspection apparatus, and the value B is memorize | stored in a control part.

In addition, the scan movement motor 55 and the optical axis direction movement motor 57 of the imaging unit holder 54 are equipped with an encoder or the like, and move from each reference position (home position) and reference position (home position). Install a mechanism to detect the distance.

FIG. 5 is a diagram illustrating an operation of the imaging unit in the second embodiment, and an operation of controlling the imaging unit at the focal length with respect to the film work at the time of pattern imaging will be described using the same figure.

Similarly to the first embodiment, a flat plate on which a test pattern is formed is placed below the imaging unit 51 and the distance sensor 59, and the focal point in which a pattern image is formed on the CCD line sensor 32 by the distance sensor 59 is formed. The distance F is obtained and stored in the controller of the device.

The film workpiece | work W in which an inspection is performed is provided in a pattern inspection apparatus, the film workpiece W is conveyed, and the part which inspects is stopped by the inspection part of an apparatus.

As shown in FIG. 5A, the imaging unit holder 54 is moved in the width direction (X direction) of the work by the scan movement motor 55.

However, it is necessary to start the movement of the imaging unit holder 54 before the distance B or more with respect to the test | inspection area | region in which the pattern is formed.

The scanning direction (X direction) movement distance Xn (X0, X1, X2, X3 ...) with respect to the reference position (origin position XO) of the scanning movement motor 55 is detected by the encoder of the scanning movement motor 55. Then, it is sent to the control part 4.

In response to the scanning direction (X direction) moving distance Xn (X0, X1, X2, X3 ...), the distance sensor 59 is the distance An (A0, Al, A2, A3 ...) to the workpiece surface. Is measured and sent to the control unit 4 of the apparatus.

The control unit 4 compares the measured distance data An with the stored focal length F and calculates the difference An-F = an (a0, a1, a2, a3 ...). The calculated an is memorize | stored in the memory | storage part of the control part 4 corresponding to the scanning direction (X direction) movement distance Xn at that time.

As shown in FIG.5 (b), the scanning movement of the imaging unit holder 54 to the workpiece width direction continues, and the scanning direction (X direction) movement distance X of the distance sensor 59 and the imaging unit is It reaches the distance B of the optical axis L. That is, X = B = Xb.

At this time, the control part 4 calls out the A0-F value a0 memorize | stored corresponding to X0, and from the origin position Z0 of the optical axis L direction (Z direction) of the imaging unit 51, for a0 minutes, The optical axis direction moving motor 57 is driven so that the imaging unit 51 descends in the optical axis L direction.

Thereafter, the imaging unit 51 scans and moves in the workpiece width direction. When the scanning direction (X direction) movement distance X of the imaging unit holder 54 turns into X (b + n), the control part 4 stores the An-F value an corresponding to the value of Xn. The optical axis direction moving motor 57 is driven so that the imaging unit 51 is lowered by an minute from the origin position Z0 in the optical axis L direction.

Thereby, the imaging unit 51 is maintained by the focal length F in the position which image | photographs a pattern image.

In the case of this embodiment, since the distance to the workpiece surface can be measured by the distance sensor 59 with respect to the position where the image is acquired by the CCD line sensor 32, the amount of curvature of the film work W is Even if the case is different in the longitudinal direction of the workpiece, the pattern to be inspected is highly focused with high precision.

In addition, since the distance sensor 59 is provided in the direction (X direction) which scan-moves with respect to the imaging unit 51, the imaging unit is located in the position where the distance sensor 59 measured the distance to the workpiece surface. Until 51 arrives, a time delay (time difference) occurs.

Since the control part 4 can calculate the optical axis L direction (Z direction) movement distance of the imaging unit 51 between this grace time, even if it speeds up a scanning (X direction) movement, it focuses on an imaging unit. By moving to the distance F, an image pattern image formed can be acquired, and the inspection processing time can be shortened.

Fig. 6 is a diagram showing the configuration of the third embodiment of the inspection section of the pattern inspection apparatus, and the third embodiment of the present invention will be described using the same drawing.

2, the reflective illuminating means 21 is omitted, and the same components as those in FIG. 2 are denoted by the same reference numerals.

Similarly to the second embodiment, this embodiment is configured such that the distance can be measured by the distance sensor at the position where the image is acquired by the CCD line sensor.

The distance sensor 59 is a direction orthogonal to the longitudinal direction of the CCD line sensor 32, and is a post 62 from the lens unit 53 in the front direction (the front in the X direction) in which the imaging unit 51 is scanned and moved. It is supported by and installed, and the distance from the position to the workpiece surface is measured.

Therefore, similarly to the second embodiment, the distance to the work can be measured with respect to the position at which the image is acquired by the CCD line sensor, but the distance sensor moves in the optical axis direction together with the imaging unit as in the first embodiment. do.

Similarly to the second embodiment, from the position (sensor position) where the distance sensor 59 measures the distance to the film work W, the position at which the pattern image is acquired by the CCD line sensor 32 (imaging unit 52 The distance B up to the optical axis L) is measured when the pattern inspection apparatus is manufactured, and the value B is stored in the control unit.

In addition, the scan movement motor 55 and the optical axis direction movement motor 57 are provided with mechanisms, such as an encoder which can detect the movement distance from a reference position (home position) and a reference position (home position).

7 and 8 are diagrams for explaining the operation of the imaging unit in the third embodiment, and the operation for controlling the imaging unit at the focal length with respect to the film work at the time of pattern imaging will be described using the same figure below. do.

Similar to the first and second embodiments, using the test pattern, the distance sensor 59 obtains a focal length F in which a pattern image forms on the CCD line sensor 32, and stores it in the controller 4 of the apparatus. .

The film workpiece | work W by which inspection is performed is provided in a pattern inspection apparatus, the film workpiece W is conveyed, and the part which inspects is stopped by the inspection part of an apparatus.

As shown in FIG. 7A, the imaging unit holder 54 moves in the width direction (X direction) of the workpiece W by the scan movement motor 55, but as in the second embodiment, As with the second embodiment, the movement of the imaging unit holder 54 needs to start movement before the distance B or more with respect to the image acquisition start position of the pattern.

The scanning direction (X direction) movement distance Xn (X0, X1, X2, X3 ...) with respect to the reference position (origin position X0) of the scanning movement motor 55 is detected by the encoder of the scanning movement motor 55. Then, it is sent to the control part 4.

 In response to the scanning direction (X direction) moving distance Xn (X0, X1, X2, X3 ...), the distance sensor 59 is the distance An (A0, A1, A2, A3 ...) to the work surface. Is measured and sent to the control unit 4 of the apparatus.

The control unit 4 compares the measured distance data An with the stored focal length F and calculates the difference An-F = an (a0, a1, a2, a3 ...).

The calculated an is memorize | stored in the memory | storage part of the control part 4 corresponding to the scanning direction (X direction) movement distance Xn at that time.

Moreover, the optical axis L direction (Z direction) movement distance Zn (Z0, Z1, Z2, Z3 ...) with respect to the reference position (origin position Z0) of the imaging unit holder 54 is also the optical axis direction movement motor 57 Is detected by the encoder and sent to the controller 4.

The control part 4 stores the optical axis L direction (Z direction) movement distance Zn in the storage part corresponding to the scanning movement distance Xn.

In accordance with the above, the value an of An-F and the movement distance Zn in the optical axis L direction (Z direction) are stored corresponding to the scan movement distance Xn of the imaging unit holder 54.

As shown in FIG.7 (b), the scanning movement of the imaging unit holder 54 to the workpiece width direction is continued, and the scanning direction (X direction) movement distance X becomes the distance sensor 59 of an imaging unit. It reaches the distance B of the optical axis L. That is, X = B = Xb.

At this time, the control part 4 calls out A0-F value a0 memorize | stored corresponding to X0, and the movement distance Z0 of an optical axis L direction (Z direction).

And from the origin position Z0 of the optical axis L direction (Z direction) of the imaging unit 51, the optical axis direction movement motor 57 so that the imaging unit 51 may descend to the optical axis L direction (Z direction) by a0 + Z0 minutes. ).

In FIG. 7B, Z0 = 0, and the amount of movement in the Z direction of the imaging unit 51 is a0.

In addition, in FIG.7 (b), since the movement amount of a scanning direction (X direction) is Xb, the difference ab with the focal length F obtained by distance data ab at this time, and Z movement distance Zb = corresponding to Xb Remember aO

Thereafter, the imaging unit 51 scans and moves in the workpiece width direction.

When the scanning direction (X direction) movement distance X of the imaging unit holder 54 becomes X (b + n), the control part 4 stores the value An-F an corresponding to the value of Xn, and The optical axis direction movement motor which calls out the optical axis L direction (Z direction) moving distance Zn, and moves the imaging unit 51 to the optical axis L direction by an + Zn minutes from the origin position Z0 of the imaging unit holder 54. Drive 57.

That is, as shown in Fig. 8C, for example, when the imaging unit holder 54 moves from Xb to a distance B and reaches Xm, the control unit 4 stores corresponding to the value of Xb. Ab-F value ab and the optical axis L direction (Z direction) moving distance Zb (= a0 + Z0) are called out, and the imaging unit 51 moves in the optical axis L direction by ab + Zb minutes, and the optical axis direction The moving motor 57 is driven.

As a result, the imaging unit 51 is maintained at the focal length F. FIG.

Thereby, the imaging unit 51 is maintained by the focal length F in the position which image | photographs a pattern image.

In the case of this embodiment, since the distance to the workpiece surface can be measured by the distance sensor 59 with respect to the position where the image is acquired by the CCD line sensor 32, similarly to the second embodiment, the film work ( Even if the amount of curvature of W) is different from that in the longitudinal direction of the work, the precision is focused highly with respect to the pattern to be inspected.

In addition, the distance sensor 59 is provided at intervals in the direction (X direction) which scan-moves with respect to the imaging unit 51, and the imaging unit (at the position where the distance sensor 59 measured the distance to the workpiece surface ( Since the time delay (time difference) arises until 51, and the control part 4 can calculate the optical axis L direction (Z direction) movement distance of the imaging unit 51 between these grace time, Even if the speed of the scanning (X-direction) movement is increased, the imaging unit can be moved to the focal length F to acquire an image pattern image, and the inspection processing time can be shortened.

Moreover, in the said Example, although the mechanism and operation | movement which move the imaging unit 51 to the optical axis L direction in order to hold the imaging unit 51 to the focal position F with respect to the film work W were demonstrated, the imaging unit was demonstrated. The position of the optical axis L direction of 51 may be fixed, and the film workpiece W may be moved to the optical axis L direction, and the same effect can be acquired.

In particular, when high resolution is required, the imaging unit 51 may become heavy by increasing the number of lenses of the lens unit 53, and in such a case, the imaging unit 51 moves in the optical axis L direction. Rather than making it move, the structure of a drive mechanism etc. becomes simpler to move the film workpiece W. FIG.

FIG. 9 is a diagram showing the configuration of the fourth embodiment of the inspection section of the pattern inspection apparatus, and an embodiment of moving the film work in the optical axis direction of the imaging unit will be described using the same drawing. In addition, in the same figure, the structure similar to the said Example is shown with the same code | symbol.

The distance sensor 59 is supported by the support 61 on the imaging unit holder 54 and is orthogonal to the longitudinal direction of the CCD line sensor 32 as in the second embodiment. 51 is provided in the front direction (X direction forward) to which a scanning movement is carried out, and the distance from the position to the workpiece | work W surface is measured.

Moreover, from the position (sensor position) which the distance sensor 59 measures the distance to the film work W, the position where the pattern image is acquired by the CCD line sensor 32 (optical axis L of the imaging unit 52). The interval up to is set and measured at the time of manufacturing a pattern inspection apparatus, and is memorize | stored in the control part.

Unlike the first to third embodiments, only the scan movement motor 55 is set in the imaging unit holder 54, and the imaging unit holder 54 is provided with the rail 56 by the scan movement motor 55. As it moves along), the imaging unit 51 scan-moves in the width direction (X direction) of the film work W. As shown in FIG.

Moreover, the encoder etc. are attached to the scanning movement motor 55, and the movement distance from a reference position (origin position) regarding a X direction, and a reference position (origin position) is detected.

The work edge holding mechanism 90 which hold | maintains both ends (edge) of the workpiece | work W, and pulls the workpiece | work W in the width direction on both sides of the width direction of the film workpiece W of the test | inspection part 5, and gives tension On one plate 91. Moreover, regarding this work edge holding mechanism 90, the detailed structural example is shown by the Japanese Patent Application No. 2004-197595, for example.

The plate 91 is provided with a plate moving mechanism 92 for moving the plate 91 in the optical axis L direction (Z direction) of the imaging unit 51, and as the plate 91 moves, the work edge holding mechanism 90 is in the optical axis L direction (Z direction).

Therefore, as the workpiece edge holding mechanism 90 moves in the optical axis L direction (Z direction) while holding the film workpiece W, the film workpiece W approaches or is separated from the imaging unit 51. .

 Next, the operation of controlling the film work at the focal length with respect to the imaging unit during pattern imaging will be described.

Similarly to the above embodiment, a flat plate on which a test pattern is formed is placed below the imaging unit 51 and the distance sensor 59, and the focal length at which the pattern image is formed on the CCD line sensor 32 by the distance sensor 59 is set. Is obtained and stored in the control unit of the device.

The film workpiece | work W by which inspection is performed is provided in a pattern inspection apparatus, the film workpiece W is conveyed, and the part which inspects is stopped by the inspection part of an apparatus.

The workpiece edge holding mechanism 90 holds the edges (edges) in the width direction of the film work W. As shown in FIG. The work edge holding mechanism 90 moves minutely in the width direction of the work W, and gives tension to the width direction of the work W to reduce the blur generated in the width direction of the work W. As shown in FIG.

The scan movement motor 55 operates to move the imaging unit holder 54 in the width direction (X direction) of the workpiece.

As in the second embodiment, the scanning direction (X direction) movement distance with respect to the reference position (origin position) of the scanning movement motor 55 is detected by the encoder of the scanning movement motor 55, and the control unit 4 Is sent.

In response to the scanning direction (X direction) moving distance, the distance sensor 59 measures the distance to the workpiece surface and sends it to the controller 4 of the apparatus.

The control unit 4 compares the measured distance data with the stored focal length, calculates the difference, and stores the stored portion in the storage unit of the control unit 4 in response to the scanning direction (X direction) movement distance at that time. do.

Then, when the imaging unit 51 moves in the X direction and reaches the position where the difference with the focal length is calculated, the control unit 4 calls out the difference with the focal length stored, and the plate moving mechanism 92 is moved. By driving, the plate 91 is moved in the optical axis L direction (Z direction) of the imaging unit 51 by a distance portion corresponding to the difference with the focal length.

As the plate 91 moves, the work edge holding mechanism 90 and the film work W held thereon move in the optical axis L direction (Z direction) of the imaging unit 51, and as a result, the film work ( W) is located at a focal length with respect to the imaging unit 51.

Subsequently, in accordance with the scanning movement of the imaging unit 51 in the workpiece width direction (X direction), the distance measurement to the workpiece surface by the distance sensor 59 and the difference between the distance measured by the controller 4 and the focal length are measured. By repeating the calculation and storage of the film workpiece W in the optical axis L direction (Z direction) by the plate moving mechanism 92, the film workpiece W is positioned at the position at which the pattern image is imaged. The focal length is maintained with respect to 51.

In the present invention, when the imaging unit moves in the width direction of the film work to acquire an image of the pattern, the imaging unit or the film work moves in the optical axis direction of the imaging unit based on the distance information from the distance sensor, and the curved shape Since the film is held at the focal position with respect to the film work, the image without blurring can be obtained by one scan.

Further, by providing the distance sensor in a direction orthogonal to the longitudinal direction of the CCD line sensor, which is an imaging element, in the forward direction in which the imaging unit is scanned, the distance can be measured with respect to the portion where the CCD line sensor acquires an image. Therefore, a highly accurate image can be focused and a pattern image without blurring can be obtained.

Claims (3)

In the pattern inspection apparatus of the film workpiece which scans an imaging unit in the width direction of a elongate film workpiece | work, acquires and examines the image of the pattern formed on this film workpiece, The imaging unit includes an imaging device which is a line sensor arranged along the longitudinal direction of the film work, and an optical device that projects the pattern on the film work onto the imaging device, A scanning movement mechanism for moving the imaging unit in the width direction of the film work, an optical axis direction movement mechanism for moving the imaging unit in the optical axis direction of the imaging unit, and scanning movement with the imaging unit by the scanning movement mechanism A distance sensor for measuring the distance to the film work, and a controller for driving the optical axis direction moving mechanism based on the distance information from the distance sensor to maintain the imaging unit at a focal length with respect to the film work. The pattern inspection apparatus of the film work characterized by the above-mentioned. In the pattern inspection apparatus of the film workpiece which scans an imaging unit in the width direction of a elongate film workpiece | work, acquires and examines the image of the pattern formed on this film workpiece, The imaging unit includes an imaging device which is a line sensor arranged along the longitudinal direction of the film work, and an optical device that projects the pattern on the film work onto the imaging device, A scanning movement mechanism for moving the imaging unit in the width direction of the film work, a work edge holding mechanism for holding both ends in the width direction of the film work, and an optical axis direction for moving the work edge holding mechanism in the optical axis direction of the imaging unit The workpiece edge holding mechanism is a film workpiece based on a distance sensor for measuring a distance to the film work while scanning movement with the imaging unit by a movement mechanism, the scanning movement mechanism, and the distance information from the distance sensor. And a control unit for driving the optical axis direction moving mechanism in a state of holding and holding the imaging unit at a focal distance with respect to the film work. The method according to claim 1 or 2, The said distance sensor is a direction orthogonal to the longitudinal direction of the said line sensor, and it is provided in the front direction to which the said imaging unit scans and moves, The pattern inspection apparatus of the film workpiece characterized by the above-mentioned.

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