JP2007279021A - Optical defect inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein the surfaces of plane mirrors are deteriorated and reflectances thereof become low and cannot secure sufficient luminous energy, when the same portions of the first plane mirror and the second plane mirror are irradiated with a thin beam of high irradiation density over a long time, in case of using a laser beam as a light source, and to prolong the service life of the each plane mirror, without having to change the optical axis itself. <P>SOLUTION: A path of the laser beam L1, emitted from the laser light source, is deflected by the first and second plane mirrors 4a, 4b to be made incident into a beam expander 5. The surfaces are deteriorated, with the irradiation of the laser beam L1 in the first and second plane mirrors 4a, 4b, to make the reflectances get worse. This optical defect inspection device is formed into structure, capable of rotating specular faces on faces including the respective first and second plane mirrors 4a, 4b, or a structure capable rather than not of rotating but moving the specular faces in parallel, at positions on the first and second plane mirrors 4a, 4b irradiated with the laser beam L1, in order not to bring the luminous energy incident into the expander 5 into a reference value or smaller by the reduction in the reflectance in the each, and in order not to change the optical axis itself, when the irradiation of the laser beam L1 exceeds a fixed time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inspection apparatus and inspection method for an inspection object. For example, it is suitable for a defect inspection apparatus and a defect inspection method for inspecting foreign matters, defects, and the like of an inspection object in a manufacturing process of a semiconductor device, a flat panel display, a magnetic disk, and a mask.

  For example, an optical defect inspection apparatus that irradiates an inspection object such as a semiconductor device or a flat panel display panel, detects reflected or scattered light, and detects defects on the inspection object. In order to detect a simple defect, it is necessary to use a light source with higher brightness. Therefore, the use of laser light as a light source has become the mainstream.

  When laser light is used as a light source, a thin beam having a high irradiation density must be used to avoid an increase in the ND filter mechanism up to the ND filter that adjusts the light amount. Further, in order to ensure the degree of freedom of the device layout, a configuration is generally adopted in which a thin beam having a high irradiation density is reflected a plurality of times in the device housing using a reflecting mirror (for example, a plane mirror). In this case, when the laser beam is irradiated to the same position of the reflecting mirror for a long time, the mirror surface of the irradiated part is deteriorated, and the problem arises that the reflectance decreases and the necessary illumination intensity cannot be maintained.

  If the reflectivity drops, it is necessary to replace the reflector. After the replacement, a slight deviation of the optical axis is inevitable. In order to correct this optical axis shift, Patent Document 1 discloses that a mechanism for changing the angle of a plane mirror (reflecting mirror) is provided.

JP 2004-45111 A

  The conventional apparatus is configured such that the laser beam is irradiated to the same point on the reflecting mirror in order to avoid complicated optical axis adjustment. However, it is problematic in terms of cost to replace the reflecting mirror every time the reflectance decreases. In order to avoid the replacement, it is not easy for the conventional apparatus to change the laser irradiation point on the reflecting mirror.

  In the present invention, when a laser beam is used as a light source, if a thin beam having a high irradiation density is irradiated to the same part of the first reflecting mirror and the second reflecting mirror for a long time, the surface of the reflecting mirror deteriorates and the reflectance decreases. In view of the fact that a sufficient amount of light cannot be secured, the object is to extend the life of the reflecting mirror without changing the optical axis itself.

In order to solve the above object, the beam irradiation position on the first reflecting mirror and the second reflecting mirror for folding the beam is rotated on the surface including the reflecting mirror so that the optical axis itself does not change. A mechanism that uses a portion where the reflectance is not lowered by changing the reflection position on the reflecting mirror by performing parallel movement or both is installed. These mechanisms can be performed manually, automatically, or in a preprogrammed procedure based on the irradiation intensity measured before and after the reflecting mirror.
One feature of the present invention is that the laser source, the first reflecting mirror that folds the beam emitted from the laser source at a predetermined angle, and the beam folded by the first reflecting mirror are folded again to A surface inspection apparatus having a beam deflection mechanism comprising: a second reflecting mirror that generates a beam traveling in a predetermined direction with respect to a beam emitted from a laser source, wherein the first reflecting mirror is provided. In addition, a reflecting mirror moving mechanism for moving at least one of the second reflecting mirrors while maintaining the incident angle and the reflecting angle of the laser beam is provided.
Another feature of the present invention is that at least one of the predetermined folding angle of the laser beam of the first reflecting mirror or the predetermined folding angle of the laser beam of the second reflecting mirror is approximately 90 degrees. The reflecting mirror moving mechanism includes a mechanism for moving the reflecting mirror to be moved substantially parallel to the reflecting surface.
Still another feature of the present invention is that at least one of the predetermined folding angle of the laser beam of the first reflecting mirror or the predetermined folding angle of the laser beam of the second reflecting mirror is substantially The reflecting mirror moving mechanism includes a mechanism for rotating the first reflecting mirror or the second reflecting mirror while maintaining substantially parallel to the mirror surface.
Still another feature of the present invention is that the reflecting mirror moving mechanism further includes a mechanism for linearly moving while maintaining substantially parallel to the mirror surface.
Still another feature of the present invention is that a light intensity measuring mechanism for measuring the light intensity of the laser beam reflected from at least one of the first reflecting mirror and the second reflecting mirror is provided.

  By providing the reflecting mirror of the present invention with a translation mechanism and a rotating mechanism that do not displace the optical axis, the frequency of component replacement can be reduced, and optical axis correction of the reflecting mirror (for example, a plane mirror) becomes unnecessary.

  The defect inspection apparatus of the present invention includes a parallel movement mechanism and a rotation mechanism that do not displace the optical axis of a reflecting mirror (for example, a plane mirror), so that fluctuations such as a decrease in light amount due to deterioration of the reflecting mirror (for example, a plane mirror) can be achieved. It is realized to suppress.

FIG. 1 shows an embodiment of the apparatus of the present invention. From a laser light source 3 that generates illumination light such as visible laser light and ultraviolet laser light, and a plurality of plane mirrors (reflecting mirrors) such as a first plane mirror 4a and a second plane mirror 4b that deflect the path of the oscillated laser beam L1. The configured beam deflection mechanism 4, the ND filter 6 for adjusting the amount of light, the expander 5 for adjusting the beam diameter, the beam splitter 30 for branching the laser beam L1, and the one of the branched laser beams L1 with the beam shape adjusted to be inspected It comprises an objective lens 11 that irradiates the surface of the object 2, a beam profile observation camera 31 that images the other branched laser beam L1, a host computer 71 that controls the entire apparatus, and the like.
The first plane mirror 4a is disposed so as to fold the laser beam L1 at a predetermined angle, and the second plane mirror 4b folds the folded laser beam L1 again at a predetermined angle, so that the laser light source 3 The laser beam L1 is configured to travel in a predetermined direction with respect to the emission direction. In this embodiment, the turning angles of the laser light L1 are both approximately 90 °, and the laser light source 3 and the optical element can be arranged in a different manner, for example, adjustment of the optical system or the laser light source 3 Maintenance such as replacement due to the service life of the product has been improved.
The folding angle of the two laser beams L1 is not limited to being set to approximately 90 °, and it is sufficient that at least one of them is approximately 90 °. Further, if the turning angle of the laser beam L1 is other than 90 °, a plurality of plane mirrors may be alternately arranged to capture the irradiation and reflection laser beam L1. Even if the angle of the plane mirror is substantially parallel or the angle of the plane mirror in the middle is changed, any configuration that can deflect in a predetermined course direction may be used.

The laser light L1 oscillated from the laser light source 3 is changed by about 90 ° by the first plane mirror 4a and deflected downward in the course direction, and further changed by about 90 ° by the second plane mirror 4b, and the course direction is changed to the horizontal direction. To deflect. The laser light L1 whose trajectory is deflected is adjusted in light quantity by the ND filter 6, and then enters the beam expander 5 to adjust the beam diameter.
The first plane mirror 4a and the second plane mirror 4b are controlled by the plane mirror moving mechanism control unit 41, and the laser beam is maintained while maintaining the incident angle and the reflection angle by the plane mirror moving mechanism 40a and the plane mirror moving mechanism 40b corresponding to each plane mirror. The irradiation site of L1 can be moved. That is, the irradiated portions of the plane mirror 4a and the plane mirror 4b irradiated with the laser beam L1 can be changed without displacing the optical axis. The light amount adjustment of the ND filter 6 is controlled by the ND filter moving mechanism control unit 60 via the ND filter moving mechanism 61, and the beam diameter adjustment of the beam expander 5 is adjusted via the beam expander adjusting mechanism 50. It is controlled by the panda adjustment mechanism control unit 51.
Next, the laser light L1 that has passed through various optical elements and whose beam state such as the polarization state and the beam diameter is controlled is branched into two by the beam splitter 30. One of the branched laser beams L1 passes through several optical elements to adjust the shape and state of the beam, and is irradiated onto the surface of the inspection object 2 through the objective lens 11. The other branched laser beam L1 is imaged by the beam profile observation camera 31, and the position of the beam of the laser beam L1 and the illuminance distribution in the beam are displayed on the monitor.
The host computer 71 receives data between the plane mirror movement mechanism control unit 41, the ND filter movable mechanism control unit 60, the beam expander adjustment mechanism control unit 51, and the like based on commands from an input device (not shown) such as a keyboard and a mouse. , And the mechanism parts such as the plane mirror moving mechanisms 40a and 40b, the ND filter movable mechanism 61, and the beam expander adjusting mechanism 50 corresponding to them are driven to control the beam state of the laser light L1. In addition, control of the entire defect inspection apparatus such as setting registration of various setting conditions, inspection results, the operation state of the inspection apparatus, etc. are displayed on the monitor 70, and further the information is output to an output device (not shown) Do.

FIG. 2 shows a schematic configuration of the plane mirror moving mechanism 40a. Since the plane mirror moving mechanism 40b has the same configuration, the plane mirror moving mechanism 40a is shown as a representative.
The plane mirror moving mechanism 40a includes a stage 45a for fixing the plane mirror 4a, an advancing / retreating drive mechanism (linear drive mechanism) 42a for moving the reflecting surface of the plane mirror 4a substantially in parallel, and a plane mirror while maintaining substantially parallel to the reflecting surface. The rotation drive mechanism 43a that rotates 4a, the angle correction mechanism 46a that corrects the angle of the reflecting surface, and the distance correction mechanism 47a that corrects the distance between the laser light source 3 and the plane mirror 4a or the plane mirrors 4a and 4b. Each of the advance / retreat drive mechanism 42a, the rotation drive mechanism 43a, the angle correction mechanism 46a, and the distance correction mechanism 47a is provided with a position detection device (not shown).
The plane mirror moving mechanism control unit 41 calculates the position coordinates of the plane mirror 4a based on a signal from a position detection device (not shown), and moves the advance / retreat drive mechanism 42a and the rotation drive mechanism 43a to the position coordinates indicated by the host computer 71. Control through. The calculation of the position coordinates may be performed by the host computer 71. The position of the plane mirror 4a fixed to the stage 45a is changed by rotating the rotation drive mechanism 43a and moving in one axial direction of the advance / retreat drive mechanism 42a with the start point irradiated with the laser light L1 as the approximate center of the plane mirror 4a. The Therefore, the irradiation part of the laser beam L1 moves relative to the reflection surface of the plane mirror 4a in a spiral shape, a spiral shape, or a circle shape while maintaining the state of the optical axis, and enlarges the usable area of the reflection surface. This usable area is controlled by the movement pitch of the advance / retreat drive mechanism 42a, and the life of the plane mirror 4a is dramatically improved. Further, by providing the position detection device, it is possible to accurately capture the coordinates of the irradiated region, and it is possible to restore the past examination state and to search and select a good reflection surface in the plane mirror 4a. Furthermore, by providing the angle correction mechanism 46a and the distance correction mechanism 47a, it is possible to absorb individual differences such as the mounting accuracy of the flat mirror 4a, thickness, parallelism, and surface deflection, and to easily correct the optical axis when replacing parts. (Automation) and stable optical axis state can be maintained.

  In the present embodiment, the plane mirror moving mechanism 40a is shown in which the use efficiency of the plane mirror 4a is high and the optical axis is held with high precision. However, the plane mirror 4a may be configured only by a moving mechanism that moves the reflecting surface of the plane mirror 4a substantially in parallel. good. Moreover, you may comprise only the moving mechanism which rotates the plane mirror 4a in the state which maintained substantially parallel with respect to the reflective surface of the plane mirror 4a. Although use efficiency is inferior to the present embodiment, there is an advantage that the size and manufacturing cost of the plane mirror moving mechanism 40a can be reduced. Further, the position detection device disposed in the advance / retreat drive mechanism 42a and the rotation drive mechanism 43a is necessary for restoring past inspection conditions and selecting a good reflection surface, but expands the use area of the reflection surface. Above is not an indispensable mechanism. A simple movement mechanism that moves the irradiation site by a predetermined amount may be used by using a mechanism known to those skilled in the art that is configured by a gear, a belt, or the like.

When the first plane mirror 4a and the second plane mirror 4b are irradiated with the laser light L1, the surfaces are deteriorated and the reflectance is lowered. In order to prevent the amount of light entering the beam expander 5 from falling below the reference value due to this decrease, for example, when the irradiation with the laser light L1 exceeds a certain time, the plane mirror moving mechanism 40a The plane mirror moving mechanism 40b is driven to change the positions on the first plane mirror 4a and the second plane mirror 4b to which the laser light L1 emitted from the laser light source 3 is irradiated. Alternatively, the host computer 71 may control the plane mirror moving mechanism control unit 41 to change the irradiation site at a time when the light intensity becomes equal to or less than a pre-recorded threshold while monitoring the change in the amount of light.
As described above, the structure in which the mirror surface of each plane mirror of the beam deflection mechanism 4 can be rotated, the structure in which the mirror surface can be moved in parallel, or a structure provided with both of them can dramatically increase the frequency of replacement of the plane mirror. In addition to reduction, optical axis adjustment is not necessary. In addition, dust can be prevented from being mixed into the optical mechanism part due to component replacement, and an increase in foreign matter caused by the optical mechanism part can be suppressed.

  FIG. 3 shows one specific practical example. Between the laser light source 3 and the first plane mirror 4a which can be rotated and translated without changing the optical axis, a pre-stage light quantity monitor 13 capable of measuring the light quantity is arranged (first light intensity measuring means). Further, a post-stage light quantity monitor 14 for measuring the quantity of reflected light is disposed after the second plane mirror 4b that can be rotated and translated without changing the optical axis (second light intensity measuring means). In the present embodiment, the total deterioration amount of the surfaces of the first plane mirror 4a and the second plane mirror 4b is measured. However, since the degree of deterioration progresses substantially equally, at least one of the reflected lights can be measured. It ’s fine. For example, the same function can be obtained even if the second light quantity measuring means is arranged between the first plane mirror 4a and the second plane mirror 4b. Further, if the amount of light does not change due to the movement of the irradiated part, it can be determined that the laser light source 3 has been changed. You may add and measure degradation of the plane mirror 4a and the 2nd plane mirror 4b. The plurality of light intensity measuring mechanisms including the front-stage light quantity monitor 13 and the rear-stage light quantity monitor 14 can be used only when measuring the light quantity by the corresponding front-stage light quantity monitor drive mechanism (not shown) and rear-stage light quantity monitor drive mechanism (not shown). When moving on the optical axis and inspecting the defect of the inspection object 2, it is removed from the optical axis.

  The initial light amount of the laser light L1 oscillated from the laser light source 3 is measured by the front light amount monitor 13, and is input to the first A / D converter 22a instead of an electric signal (analog signal). The laser light L1 attenuated by the reflection at the first plane mirror 4a and the second plane mirror 4b is measured by the post-stage light amount monitor 14, and is converted into an electric signal (analog signal) and input to the second A / D converter 22b. Is done. The respective light amounts of the laser light L1 measured by the front light amount monitor 13 and the rear light amount monitor 14 are displayed on the monitor 70. In addition to the attenuation of the amount of light by the beam deflection mechanism 4, the deterioration state of the laser light source 3 can be confirmed.

  The analog signals input to the first A / D converter 22 a and the second A / D converter 22 b are converted into digital signals here and input to the comparator 23. Based on the signal from the first A / D converter 22a, which is the initial light amount of the laser light L1, and the signal from the second A / D converter 22b, which is the laser light L1 attenuated by the beam deflection mechanism 4, The amount of deterioration of the one plane mirror 4 a and the second plane mirror 4 b is calculated by the comparator 23, and data is transmitted to the CPU 24. The deterioration amount is displayed on the monitor 70 via the CPU 24.

  The recording device 25 stores in advance a threshold value that serves as a reference for the deterioration amount through an input device (not shown). The CPU 24 compares the amount of deterioration calculated by the comparator 23, and when the threshold value is exceeded, displays a warning on the monitor 70 prompting the movement of the irradiated portions of the first plane mirror 4a and the second plane mirror 4b (on the plane mirror). Warning display means). Similarly, when the deterioration state of the laser light source 3 exceeds a predetermined value, a warning prompting replacement of the laser light source 3 is displayed (laser light source warning display means).

  The front-stage light quantity monitor 13 and the rear-stage light quantity monitor 14 installed in the above display a selection function on the display screen so that it can be executed before or at the start of alignment.

  The measurement start of the front-stage light quantity monitor 13 and the rear-stage light quantity monitor 14 installed in the above can be executed by a button or an icon displayed on the maintenance screen.

  In the above, the display on the monitor 70 is always displayed on a part of the screen after the measurement or until the movement is performed, and the movement is promoted.

  In the above, the term display is performed as the life judgment.

  When the plane mirrors 4a and 4b are moved, the operator arbitrarily sets the movement distance and operates it.

  When moving the plane mirrors 4a and 4b, the plane mirrors 4a and 4b are operated for each pitch set in the parameters.

  When the plane mirrors 4a and 4b are moved, the plane mirrors 4a and 4b are automatically operated so as to obtain an optimum light amount.

  FIG. 4 shows the setting screen of this embodiment. The diagnosis condition setting means 80 is incorporated in a setting screen for maintenance displayed on the monitor 70. The screen is not particularly limited, and the screen may be displayed using buttons and icons provided on the main screen. The diagnosis condition setting means 80 includes a measurement timing setting means 81 for setting a time point at which the light intensity is measured, a diagnosis condition setting means 82 for setting a criterion for determining whether to accept or deteriorate the diagnosis, the first plane mirror 4a, and the second The moving condition setting unit 83 sets the moving condition of the plane mirror 4b, and the light amount adjustment condition setting unit 112 sets whether to adjust the light amount of the laser light L1 when the plane mirror is moved.

  The measurement timing setting unit 81 includes an alignment time instruction unit 84 that performs measurement during the alignment process of the inspection object 2, a transfer time instruction unit 85 that performs measurement during the substrate transfer process, and a measurement at a predetermined time. It is comprised including the scheduled measurement instruction | indication means 86 which implements. The alignment time instruction means 84 includes an alignment step selection means 87 for selecting a step of whether the measurement start (starting point) is before the start of the alignment process, at the start of the alignment process, or after the completion. Further, the conveying time instruction means 85 selects the step of whether the measurement start (starting point) is to search the inspection object 2 in the cassette or the hoop, when the inspection object 2 is carried in, or when the inspection object 2 is carried out. Step selection means 88 is provided. The scheduled measurement instruction means 86 is provided with one or more time input spaces 89 for inputting measurement times, and includes time selection means 90 for selecting one or more measurement times. The measurement time can be input to the space via an input device such as a keyboard or a mouse (not shown). The timing at which the measurement is performed can be selected from among the alignment processing, the substrate transfer processing, the scheduled measurement, or a plurality of measurement timings.

  The diagnosis condition setting unit 82 includes a front-stage light amount monitor setting unit 91, a rear-stage light amount monitor setting unit 92, and a deterioration reference setting unit 93. The pre-stage light quantity monitor setting means 91 includes a first light intensity measurement instruction means 115 for instructing whether or not the light quantity measurement by the pre-stage light quantity monitor 13 is necessary, and a first threshold value input space 94 for inputting a light quantity threshold value. . When the light quantity of the laser light L1 does not satisfy the first threshold value, a warning of deterioration of the laser light source 3 and a display prompting replacement are displayed on the monitor 70. Similarly, the post-stage light intensity monitor setting unit 92 includes a second light intensity measurement instruction unit 95 and a second threshold value input space 96. When the deterioration reference setting means 93 is not used, deterioration diagnosis of the first plane mirror 4a and the second plane mirror 4b may be performed based on the light amount measurement value of the rear-stage light amount monitor 14 and the second threshold value. In the deterioration reference setting means 93, a deterioration diagnosis instructing means 97 for instructing whether or not to perform deterioration diagnosis of the first plane mirror 4a and the second plane mirror 4b, and a third threshold value input space for inputting a reference value for deterioration determination. 98. When the deterioration amount calculated by the comparator 23 does not satisfy the third threshold value, a deterioration warning for the first plane mirror 4a and the second plane mirror 4b and a display for prompting the change of the irradiated part are displayed on the monitor 70. The

The movement condition setting unit 83 includes a movement distance setting unit 99 that sets a movement distance of the first plane mirror 4a and the second plane mirror 4b, and a determination criterion setting unit 100 that sets a determination criterion for movement. The movement distance setting unit 99 includes a movement state instruction unit 101 that specifies the movement state of the first plane mirror 4a, a movement angle specification unit 102 that specifies a pitch in the rotation direction and the linear direction, and a movement distance specification unit 103. . The movement mode can be selected from three modes: rotational movement, parallel movement, and combined use of rotational movement and parallel movement (spiral movement). According to the pitches designated by the movement angle designation means 102 and the movement distance designation means 103, the movement mode can be selected. One plane mirror 4a is driven. The second plane mirror 4b is similarly configured. The criterion setting unit 100 includes a manual operation instruction unit 104 and an automatic operation instruction unit 105.
The manual operation instruction unit 104 includes a setting condition selection unit 106 that moves the first plane mirror 4a and the second plane mirror 4b under the conditions specified by the movement distance setting unit 99, and an arbitrary condition selection that moves according to the operator's instruction. It is possible to select from two modes of the means 107. When the setting condition selection means 106 is selected, a movement necessity confirmation screen is displayed when the irradiation site change warning is displayed on the monitor 70. By clicking the necessary (OK) button, One plane mirror 4a and the second plane mirror 4b move. In the case of the optional condition selection means 107, a setting screen similar to that of the movement distance setting means 99 is displayed, and movement is performed by inputting each movement pitch and clicking a button of the movement instruction means on the screen. The automatic operation instruction means 105 can be selected from two modes: a periodic movement designation means 108 that automatically moves based on a designated time limit, and a deterioration diagnosis result designation means 109 that moves based on the result of deterioration diagnosis. Yes. In the automatic operation mode, the first plane mirror 4a and the second plane mirror 4b are moved based on the conditions of the movement distance setting means 99 in both modes. The periodic movement designation means 108 is provided with a time limit designation means 110 for moving the first plane mirror 4a and the second plane mirror 4b. In this embodiment, this time limit is set as the accumulated actual irradiation time of the laser light L1 from the previous movement. Although not particularly limited to this, it may be set according to the calendar or schedule such as the elapsed time from the previous movement, the date of periodic diagnosis of the apparatus, the date of maintenance, and several hours before the start of the inspection. When the inspection cumulative actual irradiation time exceeds the time specified by the deadline specifying means 110, the first plane mirror 4a and the second plane mirror 4b are moved. The accumulated actual irradiation time (elapsed time) and the remaining time until the movement are always displayed by the term display means 111 provided in a part on the monitor 70. Further, when the condition for moving the plane mirror is selected based on the diagnosis result by the deterioration diagnosis result specifying means 109, the CPU 24 makes a determination based on the setting conditions of the measurement timing setting means 81 and the diagnosis condition setting means 82, and sets the movement distance. The conditions set in the means 99 are implemented.

The light quantity adjustment condition setting means 112 includes an adjustment acceptance / indication instruction means 113 for instructing acceptance / rejection of light quantity adjustment, and an adjustment light quantity designation means 114 for designating a light quantity value to be adjusted. The adjustment acceptance / rejection instruction means 113 can be selected from two modes of whether or not to adopt the light amount adjustment of the laser light L1 after the movement of the first plane mirror 4a and the second plane mirror 4b. The adjustment light quantity designation means 114 is constituted by an input space, and a target value of the light quantity to be adjusted can be set via the input device.
For example, when the light amount adjustment is adopted, the output of the laser light source 3 is controlled so as to become the set value of the adjustment light amount designation means 114 while measuring the light amount of the laser light L1 with the subsequent light amount monitor 14. When the CPU 24 determines that the set value is substantially the same as the light amount of the laser light L1, the light amount adjustment process ends and the output value of the laser light source 3 is fixed.

  FIG. 5 shows the history of the past light quantity state and the driving state of the plane mirror moving mechanisms 40a and 40b. The history of the light quantity measurement values of the front-stage light quantity monitor 13 and the rear-stage light quantity monitor 14, the deterioration amount calculated by the comparator, the moving dates of the first plane mirror 4a and the second plane mirror 4b, and the coordinates of the irradiated part, etc. It is stored in the storage device 25 through the CPU 24. The history management chart 116 is displayed by clicking the button of the history display means 119 provided on the monitor 70 via the input device. The measurement result of the light quantity and the driving history of the plane mirror moving mechanisms 40a and 40b are displayed as comments by selecting the plotted marks with the pointer 117. By clicking on the comment field 118, the state of the optical system is restored to the state at that time. By causing the scheduled measurement instruction means 86 to perform the scheduled measurement, the change in the optical system can be grasped more accurately.

  In this embodiment, the setting value input and display means are configured using spaces and buttons. However, any device that can input, transmit, and display signals may be used. An icon, a keyboard, or other signal input may be used. Transmission means and display means may be used.

In this embodiment, the defect inspection apparatus for detecting defects (foreign matters, dirt, cracks, crystal defects, COPs, pattern defects, etc.) of the inspection object using laser light has been described. However, the present invention is not limited to this. The present invention can also be applied to a surface inspection device, a foreign matter inspection device, or a disk inspection device.
Further, the present invention can be widely applied not only to laser light but also to an optical system using illumination light such as a halogen lamp, a mercury lamp, or an Xe lamp. For example, any inspection apparatus using light, such as an appearance inspection apparatus, a mask inspection apparatus, or a bevel inspection apparatus, can be applied.
In the present embodiment, the planar mirrors 4a and 4b are used as an example of the reflecting mirror. However, the present invention is not limited to this, and other shapes of reflecting mirrors such as a concave mirror and a convex mirror are also applicable.

The figure which shows the structure of the illumination optical mechanism concerning this invention. It is the figure which showed schematic structure of the plane mirror moving mechanism of this invention It is explanatory drawing which showed the implementation method of the plane mirror moving mechanism part of this invention, and a control part. It is a figure explaining the setting screen which sets the deterioration diagnostic condition of the plane mirror which concerns on this invention. It is a figure explaining the screen which displays the log which concerns on this invention.

Explanation of symbols

L1 Laser light 2 Inspected object 3 Laser light source 4 Beam deflection mechanism 4a First plane mirror 4b Second plane mirror 5 Expander 6 ND filter 11 Objective lens 13 Pre-stage light quantity monitor 14 Rear-stage light quantity monitors 22a and 22b A / D converter 23 Comparator 24 CPU
25 storage devices 26a and 26b motor driver 30 beam splitter 31 beam profile observation cameras 40a and 40b plane mirror moving mechanism 41 plane mirror moving mechanism control unit 42 advance / retreat driving mechanism 43 rotation driving mechanism 45 stage 46a angle correction mechanism 47a distance correction mechanism 50 beam expander Adjustment mechanism 51 Beam expander adjustment mechanism control unit 60 ND filter mechanism control unit 61 ND filter movable mechanism 70 Monitor 71 Host computer 80 Diagnostic condition setting means 81 Measurement timing setting means 82 Diagnostic condition setting means 83 Movement condition setting means 84 Alignment instruction Means 85 Transport time instruction means 86 Regular measurement instruction means 87 Arament step selection means 88 Transport step selection means 89 Time input space 90 Time selection means 91 Pre-stage light intensity monitor setting means 92 Subsequent stage Quantity monitor setting means 93 Deterioration reference setting means 94 First threshold input space 95 Second light intensity measurement instruction means 96 Second threshold input space 97 Deterioration diagnosis instruction means 98 Third threshold input space 99 Travel distance setting means 100 Judgment standard setting means 101 Movement state instruction means 102 Movement angle designation means 103 Movement distance designation means 104 Manual operation instruction means 105 Automatic operation instruction means 106 Setting condition selection means 107 Arbitrary condition selection means 108 Periodic movement designation means 109 Deterioration diagnosis result designation means 110 Time limit designation means 111 Time limit display means 112 Light quantity adjustment condition setting means 113 Adjustment acceptance / rejection instruction means 114 Adjustment light quantity designation means 115 First light intensity measurement instruction means 116 History management diagram 117 Pointer 118 Comment field 119 History display means

Claims (5)

A laser source;
A first reflecting mirror that folds the beam emitted from the laser source at a predetermined angle;
A beam deflecting comprising: a second reflecting mirror that folds the beam folded by the first reflecting mirror again to produce a beam traveling in a predetermined direction with respect to the beam emitted from the laser source; An optical defect inspection apparatus equipped with a mechanism,
An optical system comprising a reflecting mirror moving mechanism for moving at least one of the first reflecting mirror and the second reflecting mirror while maintaining the incident angle and the reflecting angle of the laser beam. Defect inspection equipment. The optical defect inspection apparatus according to claim 1,
At least one of the predetermined turning angle of the laser beam of the first reflecting mirror or the turning angle of the predetermined laser beam of the second reflecting mirror is approximately 90 degrees,
The optical defect inspection apparatus, wherein the reflecting mirror moving mechanism is a mechanism for moving a reflecting mirror to be moved substantially parallel to a reflecting surface. The optical defect inspection apparatus according to claim 1,
At least one of the predetermined turning angle of the laser beam of the first reflecting mirror or the turning angle of the predetermined laser beam of the second reflecting mirror is approximately 90 degrees,
The optical defect inspection apparatus, wherein the reflecting mirror moving mechanism is a mechanism for rotating the first reflecting mirror or the second reflecting mirror while maintaining substantially parallel to the mirror surface. In the optical defect inspection apparatus according to claim 3,
The optical defect inspection apparatus, wherein the reflecting mirror moving mechanism further has a mechanism for linearly moving the mirror while maintaining substantially parallel to the mirror surface. In the optical defect inspection apparatus according to any one of claims 1 to 4,
An optical defect inspection apparatus comprising: a light intensity measuring mechanism that measures the light intensity of laser light reflected from at least one of the first reflecting mirror and the second reflecting mirror.

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