JP2561050B2 - Repeat pattern defect inspection system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for extracting defects of an object to be inspected in which portions including repetitive patterns are arranged at a predetermined pitch, and particularly, as an image pickup apparatus, one-dimensionally scanning an electron beam, The present invention relates to a repetitive pattern defect inspection apparatus suitable for appearance inspection of a semiconductor memory (in particular, a highly integrated one having a fine repetitive pattern) integrated on a wafer by detecting the amount of electrons generated thereby.

[0002]

2. Description of the Related Art Conventionally, a semiconductor (silicon or the like) wafer is one of the objects to be inspected for a repeated pattern inspection. The wafer undergoes each wafer processing process such as oxidation, photoresist processing, diffusion, thin film formation, vapor deposition,
A circuit pattern is formed on the wafer.

Particularly, in a wafer in which a semiconductor memory is built, chips having a repetitive pattern are arranged and arranged at a predetermined pitch. Then, between adjacent chips, cutting margins for dividing the wafer into individual chips exist at equal intervals.

Conventionally, this type of inspection apparatus has two image pickup devices 1a and 1b as shown in FIG. 1, one of which picks up a repetitive pattern 5a and the other of which picks up another repetitive pattern 5b having the same pattern. Then, the video signals 2a and 2b are compared by the comparison circuit 3 and the defective portion is estimated from the mismatched portion.

However, when a fine pattern is inspected by such an apparatus, as the image pickup system becomes precise and high magnification,
A slight difference in the image signals, such as a slight positional deviation or a focus deviation between the two image pickup systems, a slight difference in the illumination state, and a difference in the distortion state of the lens system, etc. appear as erroneous detection (false alarm). , Cannot be used as an inspection device,
There was a problem.

A conventional example of this type of technique is described in Japanese Patent Application Laid-Open No. 54-19664.

In addition, there are cases where the object to be inspected has a portion other than the repeated pattern. For example, when the object to be inspected is a wafer, this corresponds to a cutting margin for dividing into individual chips. In this case, it is not necessary to compare the portions other than the repeated pattern and estimate the defective portion from the non-matching portion. This is because the repetitive patterns are not arranged in the portions other than the repetitive pattern, and if the non-repeating portion is also regarded as a defect, error detection (false alarm) will occur.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to use an electron beam in an image pickup device in order to compare extremely fine patterns. For that purpose, the imaging conditions of the two video signals to be compared should be matched as completely as possible.

[0009]

According to the present invention, an object to be inspected is an object to be inspected having a repetitive pattern in which a portion including a fine repetitive pattern such as a semiconductor memory wafer is repeatedly arranged at a predetermined pitch. The above object is achieved by adopting such a configuration.

A first invention of the present application is a defect inspection apparatus for a repetitive pattern, in which portions including repetitive patterns are arranged at a predetermined pitch, for inspecting the appearance of the repetitive pattern. A moving table that moves in the direction in which the parts are arranged and an object to be inspected are scanned by an electron beam in a direction orthogonal to the moving direction of the moving table, and the amount of electrons generated by the irradiation of the electron beam (secondarily generated An image pickup means for obtaining a video signal by detecting an electron amount (for example, a reflected electron amount), a conversion means for converting the video signal obtained by the image pickup means into a multi-valued digital signal, and an object to be inspected is scanned by the image pickup means. The object to be inspected is imaged at a position at least a predetermined pitch away from the scanning position at which the first multi-valued digital signal obtained by converting the obtained video signal by the conversion means and the first multi-valued digital signal. And a comparing means for comparing the digital signals of the second multi-level converted by the conversion means a video signal obtained by scanning in step, characterized by inspecting defects of a repeating pattern.

Furthermore, the second invention of the present application is a defect inspection apparatus for a repetitive pattern for inspecting the appearance of an object to be inspected, wherein portions including the repetitive pattern are arranged at a predetermined pitch.
A movable table that fixes the object to be inspected and moves it in the direction in which the part containing the repeated pattern is arranged, and an electron beam that scans the object to be inspected in a direction orthogonal to the moving direction of the movable table, and then irradiates with the electron beam. Imaging means for obtaining a video signal by detecting the amount of generated electrons, conversion means for converting the video signal obtained by the imaging means into a multivalued digital signal, and moving the multivalued digital signal converted by the conversion means. A delay means for delaying the time when the table moves by a predetermined pitch; a first multi-valued digital signal obtained by converting the video signal obtained by scanning the object to be inspected by the image pickup means by the conversion means and delaying it by the delay means; A second multi-valued digital signal obtained by converting the video signal obtained by scanning the object to be inspected by the image pickup means at a position shifted by a predetermined pitch from the scanning position at which the first multi-valued digital signal is obtained is converted by the converting means. And comparison means for comparing the bets, characterized by inspecting defects of a repeating pattern.

[0012]

According to the present invention, an electron beam is used in the image pickup device,
By making it possible to compare two images under exactly the same imaging conditions, it becomes possible to effectively compare two repetitive patterns with much higher precision than in the prior art, and it is possible to compare two repetitive patterns. It becomes possible to extract fine pattern defects.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 is an overall configuration diagram of this embodiment. Four
Reference numeral 10 denotes an image pickup system for picking up an image of the object to be inspected and converting it into an electric signal, 4 is an object to be inspected, 5a and 5b are repetitive patterns on the object to be inspected, and 6 is a movement for fixing and moving the object to be inspected. A platform, 7 is a position detector, 8 is a moving platform control circuit, 9 is an illuminator, and 10 is a line sensor which scans an image of an inspection object one-dimensionally and converts it into an electric signal. That is, the inspection object 4
Is fixed on the moving table 6, and the moving table is moved at a constant speed in the X direction by the moving table control circuit 8. Repeating pattern 5a
Is illuminated by the illuminator 9, and its image is detected by the line sensor 1
Image on 0. Therefore, by repeatedly driving the line sensor, the image of the repeated pattern 5a is output as the video signal S10. At this time, if the same repetitive pattern 5b as 5a is arranged in the X direction, exactly the same video signal is output as the video signal S10 with a delay of the difference between the positions of 5a and 5b. Generally, in a semiconductor memory, portions including the same repetitive pattern are arranged at a predetermined pitch. Therefore, if the video signal delayed by the predetermined pitch is compared with the video signal at that time, a mismatched portion is found. The defect of the repetitive pattern can be detected. The circuit block shown in FIG. 2 is for realizing such a function.

The output signal S10 of the line sensor 10 is AD
It is converted into a digital signal S11 by the converter 11. This is because the following processing is easier for digital signals than for analog signals. The digital video signal 11 is electrically delayed by a predetermined pitch of the repeating pattern by the delay circuit 12, and is compared with the original signal S11 by the comparison circuit 13. The comparison circuit 13 outputs the signal S1
A binary video signal S13 that takes the difference between 1 and S12 and becomes "1" when the difference is larger than a certain threshold value and "0" when the difference is smaller than the threshold value.
Is a circuit for outputting. That is, the video signal S13 is a defect video signal in which only the defect candidate area is "1".

In many cases, the defective video signal S13 actually contains noise due to minute shape variations of the repeated pattern, alignment error, and the like. Defect determination circuit 1
Reference numeral 4 is a circuit for extracting only a defective portion to be trusted from the defective image S13 including such noise. This function can be realized, for example, by determining that the area of the defect is equal to or larger than a certain threshold value as described later in detail.

Reference numeral 15 denotes a defect data storage circuit, which receives a defect detection signal S14 from the defect determination circuit, and detects the position of the moving table and the scanning coordinate y in the line sensor at that time from the position detector 7 and the timing circuit 16, respectively. It is a circuit for inputting and storing it in a memory circuit. This stored data is read by the computer 19 after the image input of the object to be inspected is finished, and is used for displaying it as defect position data to the operator.

Reference numeral 16 denotes a timing generation circuit, which is a circuit for generating various kinds of timing pulses necessary for each circuit of the device such as a synchronizing signal of the line sensor 10 and a signal scanning coordinate y on the line sensor and supplying them to each circuit. is there.

A start control circuit 17 stores the inspection start coordinates and the inspection end coordinates set by the computer 19 in advance, and "1" when the moving table position X from the position detector 7 coincides with the start coordinates. It has a function of giving an inspection start signal which becomes “0” when it coincides with the end coordinate to the timing generation circuit to notify the inspection time.

With the above arrangement, the repetitive patterns 5a and 5b on the object to be inspected can be inspected as follows. First, the computer 19 calculates the moving position of the movable table and the start and end coordinates of the inspection from the position of the repeated pattern, operates the movable table by the movable table control circuit 8, and causes the start control circuit 17 to perform the inspection start coordinate and the end coordinate. Set. The timing generation circuit 16 constantly sends a timing signal required for each circuit to drive the circuit, but when the inspection start signal S17 is received from the start control circuit 17, the defective data storage circuit starts storing defective data.
When the activation control circuit 17 detects the end of the inspection, the computer 19
To notify that the inspection is completed. When the inspection end is detected, the computer 19 reads out the defect coordinates from the defect data storage circuit 15 and records or displays them to the operator to end the inspection operation for one unit. By repeating this series of operations a required number of times, it is possible to inspect the entire surface of the inspection object.

In the above description, the digital video signal S11 and the signal S12 passing through the delay circuit 12 are
Although it is ideally assumed that the positions perfectly match, in reality, there are many cases where they do not match due to the speed fluctuation of the moving table and the inclination of the moving direction. The position shift detection circuit 18 is an effective additional circuit in such a case. That is, when there is a slight difference in position, correction can be made by adjusting the delay time of the delay circuit. Therefore, the position shift detection circuit, which will be described in more detail later, detects the amount of position shift between the two images, and the delay circuit The delay amount of 12 should be corrected.

Hereinafter, the delay circuit 12 and the position shift detection circuit 1
8. Detailed examples of the start control circuit 17, the defect determination circuit 14, and the defect data storage circuit 15 will be described to clarify that the present invention can be implemented.

First, a detailed embodiment of the delay circuit 12 will be described with reference to FIGS.

The digital video signal S11 is a clock signal CLK not shown in the shift registers 21a-21b.
The data is input one by one. The output signal of each shift register is set to 4 by the timing pulse S124.
It is set in the registers 22a to 22d every clock, and is written in the memory circuit 23 by the timing signal S122 which follows it. The write address at this time is given by the signal S123, but the counter S29 is operated by the timing signal S120 and the operation of the selection circuit 27.
Matches the content of. The counter 29 uses the timing signal S1
21 is incremented by 1 every 4 clocks. That is, by these operations, the data of the input signal S11 is grouped into four continuous data, and the data is stored in parallel in the storage circuit 2.
It will be sequentially written in 3.

In reading data, the read data from the memory circuit is set in parallel in the shift registers 24a to 24d at the rise of the timing signal S124 and is output as the signal S125 while being shifted by the clock signal CLK (not shown). Another shift register 25a
Is input to ~ 25d. Since the reading from the memory circuit 23 to the shift register is performed once every 4 clocks by the timing pulse S124, the shift register becomes just dense and 4 data are input at the same time. The parallel output from the shift registers 25a to 25d is the selection circuit 26.
Output by the delay circuit output signal S12. The address S123 of the memory circuit at the time of reading is obtained by subtracting the data of the upper bits except the lower 2 bits of the delay amount designation data S18 from the outside from the contents of the counter 29. The upper bit data excluding the lower 2 bits is the number obtained by dividing the delay amount by 4 and discarding the remainder, and is written just by the delay time in the memory circuit by subtracting from the contents of the counter. It will indicate the address of the data. By inputting the lower 2 bits as a selection signal of the selection circuit 26, the lower 2 bits are used to correct the data delay amount of 3 clocks or less. By doing so, the input signal S11 is output as the output signal S12 after being accurately delayed by an amount obtained by adding eight clocks to the delay amount designation data S18. The extra delay of 8 clocks does not cause any problem if a small amount of 8 clocks is designated at the time of use. In this embodiment, the data is read out and written in parallel every 4 clocks, but this has the advantage that the speed of the memory circuit is slower than the data clock, which is more practical. . Of course, when the data clock is faster, it is obvious that it can be dealt with by increasing the number of parallel data.

Next, a more detailed embodiment of the positional deviation detection circuit 18 will be described with reference to FIGS. In FIG. 5, there are two systems of space differentiating circuits on the left side, and there is a position shift detecting circuit on the right side. First, the space differentiating circuit will be described. Blocks 31a to 31c are one line shift registers having the number of pixels for one scan of the line sensor, and 32a to 32c and 33.
Reference characters a to 33c each represent a shift register for one pixel. 1
The shift register for pixels is composed of flip-flops for the number of bits of the input signal because the input signal is a multivalued digital signal. When the input video signal S11 is input to this circuit and each shift register is driven by the sampling clock of a line sensor (not shown), the nine signals output from each shift register consist of 3 × 3 pixels in the video plane. It corresponds to the signal of each pixel of the two-dimensional local image. Moreover, the local area of 3 × 3 pixels scans the entire image plane in synchronization with the input image signal. Therefore, the data of the peripheral 8 pixels of this 3 × 3 pixel is fully added by the adder circuit 34, and the data of the central pixel is subtracted by the signal S35 obtained through the 8 × circuit 35 and the subtractor circuit 36 to obtain the spatial differentiation, that is, The bright and dark change points can be emphasized. This spatial differential signal S36 is compared with the threshold value θ by the comparison circuit 37, and if the signal S36 is binarized so as to be “1” when the signal S36 is larger than the threshold value θ, the signal S37 will have only the light-dark boundary portion in the image. The differential binarized signal becomes "1". On the other hand, the other input video signal S12 is also converted into the differential binarized video signal S57 by a completely similar circuit. The misregistration is detected by checking the degree of coincidence with the one of the differential binarized signals obtained by slightly shifting the position on the screen, and detecting the shift amount of the image that is most in agreement.

Next, the position shift detection circuit on the right side will be described. In the figure, 38a to 38c, 58a and 58b are 1
Line shift registers, 39a to 39c, 40a, 59
a is a 1-pixel shift register. 41a to 41f
Is an EOR (exclusive OR) gate, and 42a to 42f are A
The ND gates 43a to 43f are counters. In this case, the signals S39a, S39c, S38b, and S40a are S-based for the same reason as described in the explanation of the spatial differentiation circuit.
Pixel signals that are adjacent to each other in four directions on the video centering on 39b are shown. Here, since S39b and S59a are delayed by the shift register by exactly the same time, if the input signals S11 and S12 are exactly the same, they are exactly the same signals, and S39a, S39c, and S38.
a and S40a are output signals of images obtained by spatially shifting S39b by one pixel. Therefore, the EOR gates 41a to 41f respectively determine the number of pixels that are coincident with S59a and do not coincide, that is, "1", for a certain period of time.
3a to 43f, the pattern with the smallest count value is the best matched pattern. Therefore, by checking the position of the counter with the smallest count value, the signals S11 and S1
You can know the most plausible amount of 2. The control signals S181 and S182 are control signals for moving the counter in a constant cycle, and are signals as shown in FIG. 6, for example. That is, the counter is reset in S182, and then the gate 42 is reset for a certain time in S181.
A-42f are opened and the number of "1" of the output of the EOR gates 41a-41f is counted. S183 is a result set signal to the next register 48, which sets the final result of the positional deviation detection.

The blocks 44a and 44b are minimum position detecting circuits, which are circuits for detecting and outputting the position of the counter showing the minimum value among the counters. For example, if the value of the counter 43a is the smallest, the minimum position detection circuit 44a indicates "-".
1 ", 43b" 0 ", 43c" +1 "
Is output as a signal S44a, and the result indicates the amount of positional deviation in the vertical direction. Similarly 44
b indicates the amount of positional deviation in the horizontal direction as a signal S44b, "-
Outputs 1 "," 0 "," +1 ". Blocks 45 and 4
Reference numeral 6 denotes a circuit for converting the vertical two-dimensional positional deviation amount into a one-dimensional positional deviation amount. The vertical direction positional deviation amount is multiplied by the number of pixels of one raster by a constant multiplication circuit 45, and the horizontal direction positional deviation amount is further calculated. The shift amount is added by the counter circuit 46.
Blocks 47 and 48 are an adder circuit and a register, respectively.
This is a circuit for adding a newly detected position shift amount to the current position shift amount stored in the register 48 and setting the new position shift amount in the register 48. Register 4
8 is set by the control signal S183, and its content is input to the delay circuit 12 as S18 as described above.
With the above circuit, two images S11 and S
The positional deviation amount between 12 is detected, and the delay amount can be adjusted so that S11 and S12 match.

FIG. 7 shows a more detailed embodiment of the activation control circuit 17. The blocks 63 and 64 are registers, and the inspection start coordinate X _S and the inspection stop coordinate X _E are written from the computer 19 as a signal S191 prior to the inspection. S
7 is an output signal of the position detector, which is the current position X of the mobile base.
Is always input to the coincidence circuits 61 and 62 as S7. The block 65 is the output signals S61 and S62 of the coincidence circuit.
It is a flip-flop that is set and reset by. With the start of the inspection, the movable table starts moving in the X direction,
When the position X of S7 coincides with the inspection start coordinate X _S of the register 63, the flip-flop 65 is set and the output signal S17 becomes "1" to notify the timing generation circuit 16 that the inspection is being performed. When the movable table further moves and coincides with the inspection stop coordinate X _E of the register 64, the flip-flop 65 is reset and S17 becomes “0” to notify the timing generation circuit that the inspection is stopped. In this way, the activation of the whole inspection circuit is controlled.

FIG. 8 shows a more detailed embodiment of the defect judgment circuit 14 and the defect data storage circuit 15. In the figure, 71
a to 71e are 1-line shift registers, and 72a to 72e.
e, 73a to 73e, 74a to 74e, 75a to 75e
Is a 1-pixel shift register. If this circuit is activated by the line sensor sampling clock, the "defective" video signal S13 can be input and the 5 × 5 local area video signal can be output in parallel. Blocks 76a-76e and 77
Is an adder, which sums up the number of "1" s from the parallel output 5 × 5 pixel local image. Since the input signal S13 is a "defect" image in which the defective portion is "1", the number of "1" indicates the defect area in the 5 × 5 local image. Therefore, if the defect area signal S77 is compared with the threshold value S781 by the comparator 78, the detection signal S78 becomes "1" only when the defect is large to some extent, and becomes "0" in other cases, and the "defect signal" caused by a slight noise is generated. It is possible to perform a stable defect determination without being mistaken as a defect. When "1" is output by the defect determination circuit, the moving platform coordinate signal S7 at that time is output.
(X, Y) and the scanning position signal y of the line sensor are set in the register 79, and are further stored in the storage circuit 81 at a timed timing by the one-shot circuit 80. Since the one-shot circuit 80 stores in the memory circuit 81 only at the rising of S78, it is possible to prevent each pixel coordinate of a large defect from being continuously written in the memory circuit 81. The contents of the memory circuit are read by the computer 19 as a signal S191.

From the above description, it is made clear that the present invention can be concretely implemented.

The present invention can be modified in various ways other than the above embodiment. For example, the delay circuit in FIG. 2 may be used as a simple memory circuit, and a repeating pattern may be stored in advance and repeatedly read during inspection. Also, when another pattern is sandwiched between repeated patterns, a function to temporarily stop the shift register clock by the moving platform coordinates calculated from the design data is added, and the input of another pattern is ignored. You can also make it possible to inspect. Further, instead of using a line sensor as the image pickup device, the same effect can be obtained by scanning the object to be inspected one-dimensionally with light or an electron beam that is narrowed down and detecting the amount of reflected light or the amount of reflected electrons. To be

[0033]

According to the present invention, it is possible to compare two images under exactly the same image capturing conditions by using an electron beam in the image capturing apparatus, which is much more precise than the prior art. It becomes possible to effectively compare two repetitive patterns, and it becomes possible to extract defects of a fine pattern such as a VLSI.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a conventional technique.

FIG. 2 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a delay circuit 12.

FIG. 4 is a diagram showing timing of control signals.

FIG. 5 is a detailed explanatory diagram of the positional deviation detection circuit 18.

FIG. 6 is a diagram showing timing of control signals.

FIG. 7 is a detailed explanatory diagram of a startup control circuit 17.

FIG. 8 is a detailed explanatory diagram of a defect determination circuit 14 and a defect data storage circuit 15.

[Explanation of symbols]

1a, 1b ... Imaging device, 3 ... Comparison circuit, 4 ... Inspected object,
5a, 5b ... Repeating pattern, 6 ... Moving base, 7 ... Position detector, 9 ... Illuminator, 10 ... Line sensor, S10 ... Video signal, 11 ... AD converter, 12 ... Delay circuit, 13 ... Comparison circuit, 14 Defect determination circuit, 15 Defect data storage circuit, 16 Timing generation circuit, 17 Start control circuit,
18 ... Position shift detection circuit, 19 ... Calculator.

Claims (8)

(57) [Claims] 1. A defect inspection apparatus for a repetitive pattern for inspecting the appearance of an object to be inspected, wherein parts including the repetitive pattern are arranged at a predetermined pitch. The object to be inspected is fixed, and the parts including the repetitive pattern are arranged. A moving table for moving in the direction indicated by the arrow and the object to be inspected by an electron beam in a direction orthogonal to the moving direction of the moving table, and detecting the amount of electrons generated by the irradiation of the electron beam Image pickup means for obtaining the image signal, a conversion means for converting the video signal obtained by the image pickup means into a multivalued digital signal, and a video signal obtained by scanning the object to be inspected by the image pickup means by the conversion means. The object to be inspected is scanned by the image pickup means at a position which is moved at least the predetermined pitch from the scanning position where the first multi-valued digital signal and the first multi-valued digital signal are obtained. The comparing means for comparing the obtained video signal with the second multivalued digital signal converted by the converting means, and the defect to be extracted from the comparison result of the comparing means.
A defect inspection apparatus for a repetitive pattern, comprising: a defect determination means; and inspecting a defect in the repetitive pattern. 2. A storage means for storing defect data obtained as a result of comparison by the comparison means, an inspection start coordinate and an inspection end coordinate of the repeating pattern, and the inspection object fixed to the movable table. Is moved to reach the inspection start coordinate of the repetitive pattern, the storage in the storage means is started, and when the inspection end coordinate of the repetitive pattern is reached, the start control is terminated. 2. A defect inspection apparatus for a repetitive pattern according to claim 1, further comprising: means for inspecting a defect in the repetitive pattern. 3. The inspection start coordinates and the inspection end coordinates of the repetitive pattern are stored, and the imaging is performed when the object to be inspected fixed to the movable table moves to reach the inspection start coordinates of the repetitive pattern. Inspecting a defect of the repetitive pattern, comprising start-up control means for starting capturing of the video signal from the means and terminating the capturing of the video signal from the imaging means when the inspection end coordinate of the repetitive pattern is reached. The defect inspection apparatus for a repetitive pattern according to claim 1. 4. The defect inspection apparatus for a repetitive pattern according to claim 1, wherein the repetitive pattern is a regularly arranged semiconductor memory pattern. 5. A defect inspection apparatus for a repetitive pattern for inspecting the appearance of an object to be inspected, in which portions including the repetitive pattern are arranged at a predetermined pitch. The object to be inspected is fixed, and the portions including the repetitive pattern are arranged. A moving table for moving in the direction indicated by the arrow and the object to be inspected by an electron beam in a direction orthogonal to the moving direction of the moving table, and detecting the amount of electrons generated by the irradiation of the electron beam And a conversion means for converting the video signal obtained by the image pickup means into a multivalued digital signal, and the movable table moves the multivalued digital signal converted by the conversion means by the predetermined pitch. Delay means for delaying by a time, and a first means for converting a video signal obtained by scanning the object to be inspected by the imaging means by the conversion means and delaying it by the delay means. A digital signal of a value and a video signal obtained by scanning the object to be inspected with the image pickup means at a position moved by the predetermined pitch from the scanning position where the first multivalued digital signal is obtained are converted by the converting means. comparison means and the defect judging hand of determining a defect to be removed from the comparison result of comparing the a second multi-level digital signal
And a step for inspecting a defect of the repetitive pattern described above. 6. A storage means for storing defect data obtained as a result of comparison by the comparison means, an inspection start coordinate and an inspection end coordinate of the repetitive pattern, and the inspection object fixed to the movable table. Is moved to reach the inspection start coordinate of the repetitive pattern, the storage in the storage means is started, and when the inspection end coordinate of the repetitive pattern is reached, the start control is terminated. 6. A defect inspection apparatus for a repetitive pattern according to claim 5, further comprising: means for inspecting a defect in the repetitive pattern. 7. The inspection start coordinate and the inspection end coordinate of the repetitive pattern are stored, and the image is picked up when the object to be inspected fixed to the movable table moves to reach the inspection start coordinate of the repetitive pattern. Inspecting a defect of the repetitive pattern, comprising start-up control means for starting capturing of the video signal from the means and terminating the capturing of the video signal from the imaging means when the inspection end coordinate of the repetitive pattern is reached. 6. The defect inspection apparatus for repetitive patterns according to claim 5. 8. The defect inspection apparatus for a repetitive pattern according to claim 5, wherein the repetitive pattern is a pattern of regularly arranged semiconductor memories.