JPH06281425A - Method and device for inspecting pattern hole - Google Patents

Abstract

PURPOSE:To provide a method for inspecting the pattern hole where the mechanical inspection free from subject point of view of a person is realized, the inspection time can be short, the manufacturing cost of the inspecting device is inexpensive, and the stable inspection results with high reproducibility can be obtained. CONSTITUTION:The laser beam L emitted from a laser oscillator 1 is reflected by a mirror 3, and radiated toward a shadow mask 2 having a number of pattern holes 6, and the refracted light which is refracted by one pattern hole and emitted therefrom is divided into two directions by a half mirror 4. The individual refracted light is linearly taken out by passing linear slits 8a, 8b, and the intensity of the linear refracted light is continuously detected by each unit of the charge element by CCD line sensors 9a, 9b. The diameter of the pattern hole or the like is inspected by measuring the pitch of the light and shade fringe of the refracted light from the inspection results.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object having a plurality of regularly arranged fine holes, that is, pattern holes, such as a shadow mask used in a color television.
The present invention relates to a pattern hole inspection method and device for inspecting whether or not the shape of a pattern hole is formed as specified.

[0002]

2. Description of the Related Art Conventionally, in many cases, inspection of pattern holes on a pattern hole carrier such as a shadow mask is performed.
It was not mechanically performed, and visual inspection was common. In this visual inspection, there are problems that the determination results vary due to individual differences, the examiner is extremely tired, and the like.

Further, although it is still in an experimental stage and has not been put into practical use, an inspection apparatus constituted by a combination of a microscope and an image processor has been proposed. However, with this inspection apparatus, the inspection time is very long and the manufacturing cost is very high. Therefore, the practical value is currently questioned.

On the other hand, for example, JP-A-58-35407,
According to Japanese Patent Laid-Open No. 58-35408, there is also proposed a pattern hole inspection method using optical information processing of a spatial filtering method. However, regarding this inspection method, it is difficult to obtain an ideal light source, and therefore it is difficult to obtain accuracy in the frequency domain, so that the reproduced image after filtering is very similar to the differential image, and the inspection result is not stable. was there. In addition, this conventional method does not focus on individual fine holes, but attempts to measure a set of a large number of fine holes as a whole. Therefore, from this point as well, reliable inspection is not possible. I couldn't expect it.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and realizes a mechanical inspection independent of human subjectivity, and the inspection time is short. An object of the present invention is to provide a pattern hole inspection method and an apparatus, which are low in manufacturing cost of an inspection device and can obtain stable inspection results with high reproducibility.

[0006]

As shown in FIG. 12, when coherent parallel light, that is, light with large coherence, such as laser light L, passes through a minute hole, for example, a pinhole 102 formed in a light shielding plate 101. , That pinhole 10
A diffraction pattern P is generated behind 2. Looking at the light intensity distribution along the line AA ′ for this diffraction pattern P,
An intensity waveform as shown in FIG. 13 is obtained. In this intensity waveform diagram, the interval between peaks or peaks or valleys and valleys is the pitch of light and dark stripes obtained as a result of interference due to diffraction, and this pitch value is a function of the hole diameter of the pinhole 102. Further, the shape of the diffraction pattern P has a correlation with the shape of the pinhole 102. Therefore, conversely, the shape of the pinhole 102 can be determined by obtaining the light / dark cycle or shape of the diffraction pattern P. Diffraction for the pinhole 102 occurs even if the pinhole has a circular shape or a rectangular shape. However, when the pinhole is rectangular, the diffraction width in the long side direction is narrow and the diffraction width in the short side direction is wide.

The pattern hole inspection method according to the present invention utilizes the above-described light diffraction phenomenon. Specifically, the pattern hole is irradiated with laser light toward an object to be inspected. The diffracted light diffracted by the hole and emitted is linearly extracted by passing it through a linear slit, and the intensity of the linear diffracted light is continuously detected for each minute area by a line sensor. The feature is that the shape of the pattern hole is inspected by obtaining the pitch of light and dark. Regarding the linear extraction of the diffracted light, for example, one line along the line AA 'in FIG. 12 may be extracted, or A-
Another one along the line BB ′ orthogonal to the line A ′ may be added to take out a total of two. Extraction of such two diffracted lights can be achieved, for example, by disposing a half mirror on the optical path of the diffracted lights.

Further, the pattern hole inspection apparatus according to the present invention is arranged at a rear position of the inspection object with respect to the traveling direction of the laser beam and the laser oscillator for irradiating the inspection object having the pattern hole with the laser beam. And a linear slit that linearly extracts the diffracted light emitted from the pattern hole,
The line sensor is provided at a position behind the linear slit and takes in the diffracted light linearly extracted and outputs it as a continuous light intensity signal for each minute region. Then, the shape of the pattern hole or the like is inspected by obtaining the pitch of the light and dark of the diffracted light based on the output signal of the line sensor.

As the line sensor, for example, CCD (Ch
A CCD line sensor composed of a large coupled device (1024 bits) type can be used.

[0010]

The line sensor reads the light intensity corresponding to each position in the horizontal axis direction on a charge element basis with respect to the light intensity waveform as shown in FIG. From the read result, the pitch of light and dark of the diffraction pattern P (FIG. 12) is calculated, and the hole diameter of the pattern hole or the like is obtained from the calculated pitch value. Then, it is determined whether or not the hole diameter is within an allowable range with respect to the desired hole diameter, and the quality of the pattern hole is inspected.
The above-described series of operations can be automatically performed by well-known electrical processing, and therefore, variations in determination results due to individual differences, such as those observed in visual inspection, and extreme fatigue that occurs in the inspector, etc. It can be resolved.

Further, according to the present invention, rather than collectively measuring a set of a large number of pattern holes as a whole, the diameter and shape of each pattern hole are measured by paying attention to each pattern hole. Therefore, stable and highly reproducible inspection results can be obtained. Moreover, since a microscope and a complicated image processor are not required, the manufacturing cost of the inspection device can be reduced. Further, since the linear portion of the diffraction pattern is taken out and read using the line sensor, the inspection time can be shortened.

[0012]

【Example】

(Embodiment 1) FIG. 1 shows an embodiment of a pattern hole inspection apparatus according to the present invention. This pattern hole inspection device
A laser oscillator 1 for generating a laser beam L, a plane mirror 3 for reflecting the laser beam L toward a shadow mask (inspection object) 2, a half mirror 4 arranged below the shadow mask 2, and horizontal light detection. It has a unit 5a and a vertical light detection unit 5b. Shadow mask 2
As is well known, a large number of circular minute holes for selecting an electron beam, that is, pattern holes 6, are formed in the. These pattern holes 6 are inspection targets of this pattern hole inspection device.

Each of the light detection units 5a and 5b is
It has a condenser lens 7, linear slits 8a and 8b, and CCD line sensors 9a and 9b. The linear slits 8a in the horizontal light detection unit 5a are long in the front-rear horizontal direction, while the linear slits 8b in the vertical light detection unit 5b are long in the left-right horizontal direction. That is,
Both linear slits 8a and 8b are arranged at right angles to each other.

Since the pattern hole inspection apparatus of this embodiment is configured as described above, the laser light L emitted from the laser oscillator 1 is reflected by the reflection mirror 3 and travels toward the shadow mask 2. It passes through one pattern hole 6. The laser light that has passed through the pattern hole 6 is emitted as diffracted light, which is branched in two directions by the action of the half mirror 4, and one of the branched lights is incident on the horizontal light detection unit 5a.
The other branched light enters the vertical light detection unit 5b. The laser light that has entered each of the photodetection units 5a and 5b is condensed by the condenser lens 7, and the linear slits 8a and
It is taken out as a linear light beam by 8b and taken into CCD line sensors 9a and 9b.

The linear slit 8a in the horizontal light detecting unit 5a has, for example, the diffraction pattern P in FIG.
Along the line A ′, the linear slit 8b in the vertical light detection unit 5b takes out the diffraction pattern P along the line BB ′ orthogonal to the line AA ′. The CCD line sensors 9a and 9b measure the intensity of the extracted linear diffracted light as C
The signal is read in units of CD elements and output as an electric signal, and the output signal is, for example, A / D converted and then stored in an appropriate storage device via a shift register or the like. Therefore, in this storage device, the light intensity waveform (FIG. 13) along both the lines AA ′ and BB ′ regarding the diffraction pattern P in FIG. 12 is stored in the form of a digital signal. Then, the pitches of the bright and dark stripes of the diffraction pattern P are calculated from these waveform signals in two orthogonal directions, and the size and distortion of the pattern holes 6 are obtained from the calculation result. When the pattern hole 6 is a square hole, the dimensions of the long side and the short side are obtained.

(Embodiment 2) FIG. 2 shows a second embodiment of the pattern hole inspection apparatus according to the present invention. This embodiment differs from the first embodiment shown in FIG. 1 in that the collimator lens 10 and the dove prism (Dove Pris) are provided between the shadow mask 2 and the linear slit 8 in accordance with the traveling direction of the laser light.
sm) 11 and a condensing optical system 12 are provided.
Further, in this embodiment, only one set of the linear slit 8 and the CCD line sensor 9 is prepared, and the horizontal light detection unit 5a in FIG. 1 is omitted.

The condensing optical system 12 is composed of a concave lens 13 and a convex lens 14. Dove prism 11
Is a columnar prism formed in a trapezoidal shape when viewed from the side (C direction), and emits the laser light incident from the hypotenuse face 11a from the opposite hypotenuse face 11b. The Dove prism 11 is an optical element having a property that the optical image on the incident side can be rotated twice by rotating once around the optical axis L1 as shown by an arrow D. The dove prism 11 is provided with a prism rotating device 15 constituted by a well-known rotation driving mechanism, and the dove prism 11 has an optical axis L1, that is, an optical axis of laser light. Is driven to rotate.

Since the present embodiment is constructed as described above, the light intensity is measured by the line sensor 9 with the Dove prism 11 placed at the initial angular position, and then the Dove prism 11 is moved by the prism rotating device 15. Eg 4
After rotating the diffracted light image by 5 ° and rotating the diffracted light image by 90 °, the light intensity is measured again by the line sensor 9. As in the embodiment shown in FIG. 1, the diffracted light intensity waveforms in two mutually orthogonal directions ( 13) is required. Moreover, if detection is performed at an arbitrary rotation angle with respect to the Dove prism 11, the entire area of the diffracted light can be captured in the polar coordinate system. Furthermore, in addition to detecting both circular holes and square holes, if you change the measurement mode and capture the image over the entire range until the Dove prism 11 rotates 180 °, and perform numerical processing of the inverse transformation, you can use the microscope altogether. Without doing so, a magnified real image of the hole itself can be reproduced.

(Embodiment 3) FIG. 3 shows a third embodiment of the pattern hole inspection apparatus according to the present invention. This embodiment is different from the first embodiment shown in FIG. 1 in that an XY stage 16 for supporting the shadow mask 2 is arranged between the reflection mirror 3 and the half mirror 4. . The other components are the same as those of the embodiment of FIG. 1, and the same components are given the same reference numerals and the description thereof is omitted.

The XY stage 16 is driven by an X-axis motor 18 to rotate and a feed screw 17, and is driven by the feed screw 17 to move in parallel to the horizontal direction of the drawing orthogonal to the optical axis L1 of the laser beam. X-axis stage 19 and X
A feed screw 21 (extending in a direction perpendicular to the paper surface) that is driven and rotated by a Y-axis motor 20 fixed on the axis stage 19 and a moving direction of the X-axis stage 19 that is driven by the feed screw 21. At right angles (ie
It has a Y-axis stage 22 that translates in the direction perpendicular to the plane of the drawing. The shadow mask 2 to be measured is placed on the Y-axis stage 22.

FIG. 4 shows an embodiment of an electric control system used in the pattern hole inspection apparatus of this embodiment. According to this control system, the X-axis motor control unit 24 and the Y-axis motor control unit 25 are based on the synchronization signal sent from the synchronization control unit 23.
Is activated, the X-axis motor 18 and the Y-axis motor 20 are repeatedly rotated and stopped at a predetermined timing, and the pattern holes 6 (see FIG. 1) of the shadow mask 2 (FIG. 3) are sequentially placed on the optical path of the laser beam. carry. Rotational position information of each motor 18, 20, that is, X-axis stage 19 and Y-axis stage 2
The address information 2 is sent to the pseudo code generator 26.

Both horizontal and vertical line sensors 9a and 9
The line b performs self-scanning for reading in accordance with commands from the line sensor control units 31 and 32, and linearly reads the diffracted light emitted from one pattern hole that is the measurement target. In the embodiment, reading scanning is repeated about three times for the same diffracted light. The read output signal is A / D converted by the A / D converters 27 and 28, integrated by the integration processors 29 and 30, and then sent to the arithmetic processor 33. The reason why the outputs of the line sensors 9a and 9b are integrated is to improve the S / N ratio.

The arithmetic processing unit 33 includes line sensors 9a and 9a.
The periodic pitch T in the diffracted light intensity waveform (FIG. 13) is calculated based on the output signal of b. Further, in the arithmetic processing unit 33, data about the value of the hole diameter of the pattern hole with respect to each periodic pitch T which is previously obtained by experiment or calculation is stored as a so-called look-up table (LUT). The arithmetic processing unit 33 selects a hole diameter value corresponding to the output signal of each line sensor 9a, 9b based on this LUT and uses it as horizontal axis dimension data S (h) and vertical dimension data S (v) in pseudo code. Generator 26
Output to.

The pseudo code generation unit 26 follows the X-axis address signal S (a
dx), the Y-axis address signal S (ady), the horizontal-axis dimension data signal S (h), and the vertical-axis dimension data signal S (v) are output at appropriate timing. The size determination unit 34 uses the size data S (h) and S (v) output from the pseudo code generation unit 26 as the reference level setting unit 35.
The display unit 36 displays how much the measured pattern hole size deviates from the reference value by comparison with the reference signal sent from the device. When it is necessary to activate a buzzer or other alarms, the determination result S (r) is separately output.

The synthetic data output from the pseudo code generating unit 26 is converted into an image signal by the pseudo image generating unit 37 and displayed as an image on the display unit 38 such as a CRT. For example, an image corresponding to the shadow mask is displayed on the screen, and which position of the pattern hole is defective is displayed by blinking, display by color, or another identification method. The comprehensive data is stored in the data recording unit 40.

As is apparent from the above description, according to the present embodiment, the parallel movement of the shadow mask by the action of the XY stage 16 automatically inspects the pattern holes over the entire area of the shadow mask. .

(Embodiment 4) FIG. 5 shows a fourth embodiment of the pattern hole inspection apparatus according to the present invention. In this embodiment, the shadow mask 2 placed on the XY stage 16
A quadratic prism-shaped sweeping prism 41 is provided at a front position (a front position with respect to the traveling direction of the laser light) of, and a condenser lens 42 as a Fourier transform optical unit is provided at a rear position thereof.
Is provided. The light receiving surface 9c of the CCD line sensor 9 is arranged so as to match the focal plane E-E 'of the condenser lens 42. When diffracted light emitted from some different pattern holes 6 of the plurality of pattern holes 6 formed in the shadow mask 2 is made incident on the condenser lens 42 and converted into the frequency domain, that is, Fourier transform, the position factor is determined. It can be seen that all of the diffracted beams pass through the same place after disappearing. Above focal plane E-E '
Is the same place where all the diffracted beams emitted from the condenser lens 42 pass.

The sweeping prism 41 is additionally provided with a prism rotation device 43 constituted by a known rotation drive mechanism. The prism rotation device 43 continuously rotates the sweep prism 41 in a constant direction at a predetermined speed around the central axis L2 (extending in the direction perpendicular to the paper surface).

When the parallel laser light L is incident on the continuously rotating sweeping prism 41, the laser light L moves in parallel to the left direction in the drawing as the prism 41 rotates and sweeps the surface of the shadow mask 2. By this sweeping, the laser light L passes through different pattern holes 6 one after another, and diffracted light is emitted one after another from these holes. All of these diffracted lights are collected at the same location on the focal plane E-E ', taken into the line sensor 9, and the light intensity thereof is read. Thus, the inspection for the plurality of pattern holes 6 existing in the sweep area by the prism 41 is continuously performed. Prism 41
When one side surface of the laser beam has passed through the optical path of the laser beam and the adjacent side surface comes out to the optical path, the laser beam passing through the prism 41 instantly returns to the initial position (the right end position in the figure), and the prism 41 again. The leftward sweep is repeated at a speed corresponding to the rotation of the.

XY for supporting the shadow mask 2
In-plane translation by the stage 16 and the prism 41 described above.
The entire area of the shadow mask 2 can be swept with the laser light L in a short time by combining with the sweep of. That is, as shown in FIG. 6, first, A of the shadow mask 2 is
The block (1) row is placed on the optical path of the laser beam, and the sweeping prism 41 is rotated to perform sweeping within a predetermined range in the block A. After that, the shadow mask 2 is moved to the arrow G by the parallel movement (for example, X axis movement) of the XY stage 16.
The step (2) is carried in the optical path by stepwise moving in one direction, and the prism 41 again performs the sweep. afterwards,
After step-moving to the (n) th column which is the last column, X
-By moving the Y stage 16 in parallel (for example, moving in the Y-axis), the shadow mask 2 is moved in the direction of the arrow F by the block B.
Carry the book on the light path. Then, the sweep by the prism 41 and the step movement in the G2 direction by the XY stage 16 are repeatedly executed. By repeating such prism sweep, step movement (G) and block movement (F) repeatedly, the entire area of the shadow mask 2 is swept at high speed by the laser light.

If the beam sweep width is 5 cm,
In the case of a shadow mask having a pitch of 0.3 mm, since 160 or more pattern holes 6 can be swept by the prism sweep, if shadow masks of the same size are inspected at the same time, the parallel movement by the XY stage 16 is required. Compared to sweeping the entire shadow mask just by moving,
The moving speed of the block movement (F) and the step movement (G) can be reduced to 1/160. This is nothing but the fact that the XY stage 16 can be moved slowly, so that a stable sweep and thus a stable inspection is achieved.

If the error when measuring the intensity distribution as shown in FIG. 13 is set to 0.5% or less and the effective operating area of the line sensor is set to 50% or more of all elements, 1024 pixels are considered in consideration of Nyquist rate. It is sufficient to use the CCD of. Many of the CCDs currently in widespread use have a clock rate of 20 MHz. Considering this as a reference, the sweep speed per time is about 1024 / (20 × 10 ⁶ ) ≈1 / (20 × 10 ³ ). Become.

If a shadow mask of 640 × 400 dots is considered, then 640 × 400 × {1 / (20 × 10 ³ )} seconds = 12.
It is 8 seconds, and a 14-inch shadow mask can be realized by moving 5 blocks x 400 steps, so practical values are 0.2 seconds per block movement and 0.05 seconds per step movement. For example, 0.2 x 5 + 0.05 x 400 x 5 = 101 seconds ≈ 1 minute 4
It will be 0 seconds. If data can be collected in the entire area in this time, the inspection can be performed almost twice as fast as the visual inspection by a person.

As a method for sweeping the laser light on the surface of the shadow mask, other than the method using the prism-shaped rotating prism 41, as shown in FIG. 7, the laser light L is reflected and emitted. Plane mirror 45 that guides to the object mirror 46
It is possible to adopt a method of forming a swept reference beam by causing the motor 44 to reciprocally swing and rotate. Further, as shown in FIG. 8, a method is also adopted in which a laser beam L is reflected by a polygon mirror 48 that is continuously driven to rotate in a certain direction by a motor 47 and guided to a parabolic mirror 46 to form a swept reference beam. it can. Further, as shown in FIG. 9, the laser beam L is passed through the hologram disk 5 via a hologram disk 50 driven by a motor 49 and continuously rotating in a fixed direction.
It is also possible to adopt a method of leading to 1 to form a swept beam.

However, it is considered that the swing mirror system shown in FIG. 7 and the polygon mirror system shown in FIG. 8 have complicated mechanisms and are likely to cause an error. Further, the hologram system shown in FIG. 9 has a small error, but the manufacturing cost may be high. On the other hand, the rotating prism method shown in FIG. 5 has the advantages that the mechanism is simple, the manufacturing cost is low, and the error is small.

(Embodiment 5) According to the embodiment using the rotating prism as shown in FIG. 5, it is possible to inspect a large number of pattern holes at a very high speed. And in this case X
-If the Y stage 16 is moved at a higher speed, a higher speed inspection can be realized. However, in this case, the high speed movement of the stage 16 causes the shadow mask 2 on the stage 16 to vibrate or be displaced,
There is a risk of errors in the inspection results. When the flatness of the shadow mask 2 is not accurately obtained and deformation such as warpage remains, this is particularly likely.

The embodiment shown in FIGS. 10 and 11 is intended to prevent the above-mentioned inspection error from occurring by firmly fixing the shadow mask on the XY stage. In this embodiment, the XY stage 16
The inspection target support device 52 is installed on the above. The inspection target support device 52 includes a mask support part 53 and a lift drive part 54.

As shown in FIG. 11, the mask supporting portion 53 has a mask mounting glass plate (holding transparent member) 56 fixed to a frame 55 integral with the XY stage 16.
And a mask holder 57 that moves up and down with respect to the glass plate 56. The mask mounting glass plate 56,
It is formed of a glass material that can transmit the laser light L. The mask holder 57 includes a frame frame 58, a mask pressing glass plate (holding transparent member) 59 supported by the frame frame 58, and an auxiliary glass plate (auxiliary transparent member) 60 also supported by the frame frame 58. have. Both of the glass plates 59 and 60 are made of a glass material capable of transmitting the laser light L. Further, the auxiliary glass plate 60 is formed thicker than the mask pressing glass plate 59 and is less likely to bend than the mask pressing glass plate 59.

A closed space R is formed between the mask pressing glass plate 59 and the auxiliary glass plate 60, and the air supply pipe 6 is provided.
The compressed air supplied by 2 can be introduced into the hermetically sealed space R via the air introduction path 61 provided in the frame 58. The elevation drive unit 54 is configured by an elevation drive mechanism known per se, and moves the entire mask holder 57 up and down with respect to the stage frame 55.

Since the inspection object support device 52 of this embodiment is constructed as described above, the shadow mask 2 to be used for measurement is placed on the mask mounting glass plate 56. After that, the mask holder 57 is lowered by being driven by the elevating and lowering drive device 54, and the bottom portion of the frame frame 58 is fitted into the ring-shaped concave groove 55 a of the stage frame 55. At this time, the mask pressing glass plate 59 is in a state of being close to or lightly contacting the surface of the shadow mask 2. In this state, compressed air is sent from the air supply pipe 62 into the closed space R, and the mask pressing glass plate 59 is slightly bent downward by the action of the air pressure, that is, in the direction toward the shadow mask 2. Due to this bending, the shadow mask 2 is pressed against the mask mounting glass plate 56, and both glass plates 5 are pressed.
It is clamped under pressure by 9 and 56. Due to this sandwiching, no matter how fast the XY stage 16 moves, the shadow mask 2 does not vibrate or misalign. Further, even when the shadow mask 2 is warped or some other deformation remains, the warpage or the like is corrected and accurate flatness of the shadow mask 2 is obtained.

The present invention has been described above with reference to some preferred embodiments, but the present invention is not limited to these embodiments and can be variously modified within the technical scope described in the claims. Is.

For example, the object to be inspected is not limited to the shadow mask, and any object having a plurality of regularly arranged fine holes, that is, patterned holes can be used as the object to be measured. The shape of the pattern hole is not limited to the circular shape, but may be a square shape or any other shape.

In FIGS. 1 and 3, the diffracted light emitted from the pattern hole of the shadow mask is divided into two directions,
Although the light intensity distribution waveforms (FIG. 13) in two different directions are obtained, it is also possible to obtain the light intensity distribution in one direction without branching the diffracted light.

[0044]

According to the pattern hole inspection method of the first aspect and the pattern inspection apparatus of the third aspect, the inspection of the pattern holes can be automatically performed by a well-known electrical process. It is possible to eliminate the variation in the determination result due to individual differences and the extreme fatigue that occurs in the inspector as seen. Also, instead of collectively measuring a set of a large number of pattern holes as a whole, by focusing on each pattern hole and measuring the hole diameter, shape, etc., stable and highly reproducible inspection results can be obtained. Can be obtained. Moreover, since a microscope and a complicated image processor are not required, the manufacturing cost of the inspection device can be reduced. Further, since the linear portion of the diffraction pattern is taken out and read using the line sensor, the inspection time can be shortened.

According to the pattern hole inspection method of the second aspect, since the data of the linear region portions in two different directions regarding the diffraction pattern can be obtained, the hole diameter and shape of the pattern hole can be inspected more accurately.

According to the pattern hole inspection apparatus of the fourth aspect, since the diffracted light image can be arbitrarily rotated by the rotation of the Dove prism, it is possible to obtain the data of the linear area portion in various angular directions regarding the diffraction pattern. By obtaining data on various directions, the hole diameter of the pattern hole can be inspected more accurately. Moreover, the number of optical systems including the line sensor is only one, which is very economical.

According to the pattern hole inspection apparatus of the fifth and sixth aspects, it is possible to automatically inspect a wide area of the inspection object.

According to the pattern hole inspection apparatus of the seventh aspect, a wide area of the inspection object can be inspected automatically and at a higher speed.

According to the pattern hole inspection apparatus of the eighth aspect, it is possible to provide the laser beam sweeping means which is inexpensive and has a small error.

According to the pattern hole inspection apparatus of the ninth aspect, even if the inspection object is warped or other deformation remains, it is corrected to obtain accurate flatness with respect to the inspection object. As a result, a highly reproducible inspection can be performed.

[0051]

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a pattern hole inspection device according to the present invention.

FIG. 2 is a perspective view showing a second embodiment of the pattern hole inspection device according to the present invention.

FIG. 3 is a perspective view showing a third embodiment of the pattern hole inspection device according to the present invention.

FIG. 4 is a block diagram of an example of an electric control system used in the embodiment of FIG.

FIG. 5 is a perspective view showing a fourth embodiment of the pattern hole inspection device according to the present invention.

FIG. 6 is a diagram schematically showing an example of a laser beam sweeping method in the embodiment of FIG.

FIG. 7 is a perspective view showing a modification of the laser beam sweeping means applicable to the embodiment of FIG.

FIG. 8 is a perspective view showing another modification of the laser beam sweeping means applicable to the embodiment of FIG.

FIG. 9 is a perspective view showing still another modified example of the laser beam sweeping means applicable to the embodiment of FIG.

FIG. 10 is a perspective view showing an essential part of a fifth embodiment of the pattern hole inspection device according to the present invention.

FIG. 11 is a cross-sectional view showing in detail the holding mechanism for the inspection object in the embodiment shown in FIG.

FIG. 12 is a perspective view schematically showing a general laser light diffraction phenomenon.

13 is a waveform diagram in the case where a linear portion of the diffraction pattern P shown in FIG. 12, for example, an AA ′ portion is extracted and shown as an intensity distribution waveform.

[Explanation of symbols]

 1 Laser Oscillator 2 Shadow Mask (Inspection Object) 4 Half Mirror 6 Pattern Holes 8, 8a, 8b Linear Slits 9, 9a, 9b Line Sensor 11 Dove Prism 15 Prism Rotating Device 16 XY Stage 41 Sweeping Prism 42 Collection Optical lens (Fourier transform optical means) 43 Prism rotation device 56 Mask mounting glass plate (holding transparent member) 59 Mask pressing glass plate (holding transparent member) 60 Auxiliary glass plate (auxiliary transparent member) 62 Air supply pipe (Air feeding means) R closed space L laser light

Claims (9)

[Claims] 1. A linear light is extracted by irradiating an inspection object having a pattern hole with laser light, and diffracted light diffracted by the pattern hole and emitted is passed through a linear slit to obtain a linear diffracted light. The method for inspecting a pattern hole is characterized by continuously detecting the intensity of each of the minute areas by a line sensor and measuring the pitch of light and dark of the diffracted light based on the detection result. 2. A laser beam is irradiated toward an inspection object having a pattern hole, and the diffracted light diffracted and emitted by the pattern hole is branched into two directions by a half mirror, and one of the branched diffracted lights is emitted. It is extracted linearly by passing it through the first linear slit, and the intensity of the linear diffracted light is continuously detected for each minute region by the first line sensor, and the other branched diffracted light is detected by the second linear slit. The linearly diffracted light from a region other than the first linear slit, and the intensity of the linear diffracted light is continuously detected by the second line sensor for each minute region. A pattern hole inspection method characterized by inspecting a pattern hole by measuring the pitch of the light and dark of the diffracted light from the detection result by. 3. A laser oscillator for irradiating a laser beam toward an inspection target having a pattern hole, and a diffracted light emitted from the pattern hole, which is arranged at a rear position of the inspection target in the traveling direction of the laser beam. It has a linear slit that takes out linearly and a line sensor that is arranged at the rear position of the linear slit and that takes in the diffracted light taken out linearly and outputs it as a continuous light intensity signal for each minute area. The pattern hole inspection apparatus is characterized in that the pattern hole is inspected by measuring the pitch of the light and dark of the diffracted light based on the output signal of the line sensor. 4. A Dove prism arranged on the optical axis of the laser beam and between the inspection object and the linear slit, and prism rotating means for rotating the Dove prism about the optical axis of the laser beam. The pattern hole inspection apparatus according to claim 3, further comprising a collimating lens disposed between the tab prism and the inspection object. 5. The pattern hole inspection apparatus according to claim 3, further comprising an XY stage that supports an object to be inspected and moves in-plane in a plane orthogonal to an optical axis of laser light. 6. A laser beam sweeping means disposed between the laser oscillator and the inspection object to sweep the laser beam on the inspection object, and arranged at a rear position of the inspection object with respect to a traveling direction of the laser light. 4. The pattern hole inspection apparatus according to claim 3, further comprising: an optical means for Fourier transform, wherein the light receiving surface of the line sensor is arranged on a focal plane of the optical means for Fourier transform. 7. The pattern hole inspection apparatus according to claim 5, wherein the laser beam sweeping means is provided between the laser oscillator and the inspection object and sweeps the laser light on the inspection object. It has an optical means for Fourier transform arranged at a rear position of the inspection object with respect to the traveling direction of light,
The light-receiving surface of the line sensor is arranged on the focal plane of the Fourier transform optical means, and the laser light is swept by the laser light sweeping means and the XY stage is translated to move the laser light in a wide range. A pattern hole inspection device, which irradiates a pattern hole. 8. The laser beam sweeping means comprises a prism having a quadrangular prism shape, and prism rotating means for rotating the prism about an axis extending in a direction perpendicular to the optical axis of the laser light. The pattern hole inspection device according to claim 6. 9. The pattern hole inspection apparatus according to claim 3, further comprising an inspection object support device for supporting the inspection object, the inspection object support device including the inspection object from both front and back surfaces. A pair of holding transparent members sandwiched and held, an auxiliary transparent member that cooperates with at least one of the holding transparent members to form a closed space, and an air feed for supplying air into the closed space. And a pattern hole inspection device.