JPS58154229A - Inspecting apparatus for both surfaces of masked substrate - Google Patents

Abstract

PURPOSE:To simultaneously inspect both surfaces of a masked substrate as well as eliminate the adhesion of dust and the production of any minute flaw during inspection, by supporting only peripheral parts of the masked substrate, projecting a spot of light from each side of the substrate, and providing TV cameras. CONSTITUTION:The inspection apparatus has support members 16 for supporting a masked substrate B through the engagement with only respective peripheral parts of the substrate B; projectors 21, 22 for projecting spots of light onto different parts on both surfaces of the substrate B, respectively; and a pair of TV cameras 23, 24 disposed facing the light incident positions on the masked substrate B, respectively. By this constitution, it is possible to inspect both surfaces of the masked substrate simultaneously and automatically. In addition, there is absolutely no possibility of the adhesion of dust to the reverse surface of the masked substrate as well as the production of any minute flaw during inspection.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a mask substrate inspection apparatus used in phosphorography, etc., and more particularly to a mask substrate double-sided inspection apparatus that can automatically inspect both sides of a mask substrate at the same time.

[Technical background of the invention]

Mask substrates used for photolithography in the manufacturing process of ICs, etc. are manufactured by vapor-depositing or sputtering chromium or metals such as chromium and chromium oxide on one surface of an extremely flat glass plate, and circuit patterns are printed on the wire mesh surface. After patterning is done mainly by optical methods, it is used as a mask. The circuit diagram drawn on this mask is transferred onto the wafer in a photolithography process, so if there is minute dust or scratches on the mask substrate, the circuit in that area will be damaged and ICs etc. This causes a large amount of defective convex metal to be generated in the manufacturing process. Therefore, it is necessary to inspect the surface of the mask substrate before patterning the circuit 7 figure.

Until very recently, this test was performed by visual methods, as described below. In other words, in this method, a spotlight "t" is directed diagonally above the mask substrate using a projector in a dark room, and if there is dust or scratches on the area that is being illuminated, the spot light is removed. It is based on the principle that because light is diffusely reflected, the area can be recognized as a point of high brightness when viewed with the naked eye. This method has the following problems: (a) Judgments vary depending on the individual differences of the measurer;
Lack of accuracy. (C) Eyes get tired easily because of looking at high brightness in a dark room, and judgment becomes incorrect when inspecting a large number of mask substrates. (C) Mask substrates are contaminated by dust generated by the tester. (d) The inspection speed is slow.

Therefore, the inventor filed a separate patent application, but the recent I
With the increasing integration of C and LSI, the transfer ability of the mask aligner that transfers the mask pattern onto the wafer has improved. It has become necessary to further improve the cleanliness of mask substrates, and it has become difficult for the above-mentioned apparatuses to satisfy this need.

[Problems with background technology]

FIG. 1 shows a schematic configuration of an inspection apparatus disclosed in a separate application that automates the surface inspection of a mask substrate. In the same figure, τ1 is a mask substrate mounting table, and this mounting table 1 can move in the left-right direction and in the direction perpendicular to the plane of the paper.
It is designed to be driven by a drive device 6 such as a pulse motor via the motor. The mask substrate B to be inspected is placed on the mask substrate mounting table 1 with its metal vapor deposition surface mf facing upward.
The back surface of the glass portion g is in full contact with the upper surface of the mask substrate mounting table 1. A projector 6' having a built-in light source 4 and a focusing lens 5 is disposed obliquely above the mask substrate mounting table 1, and the projector 6 faces the incident point P of the spot light projected onto the mask substrate B. A television camera 7 is installed. Reference numeral 8 denotes a position detector for detecting the position of the mask substrate mounting table 1, and the movement of the mask substrate mounting table 1 is transmitted to this position detector, for example, via a suitable mechanical coupling means 9. . 10 is a mask substrate mounting table control device that controls the drive device 6; 11 is a camera control device that controls the optical system and photoelectric conversion unit of the television camera 7; the mask substrate mounting table control device 10, the camera control device 11, and Position detector 8 is electrically connected to main controller 12 .

The main control device 12 also includes an input device 16 such as a keyboard or tape reader, an output device 14 such as a printer or a copier, and a monitor television receiver 15.
etc. are electrically connected. In the above device, if a foreign matter M adheres to a point P on the mask substrate B, it scatters light and is photographed by the television camera 7 as a high brightness point, allowing the foreign matter on the substrate to be seen.

In the mask substrate automatic inspection device of the separate application having the above configuration,
Since the surface that can be inspected is only one side of the mask substrate B, there is a drawback that it is not possible to detect adhering dust or scratches on the other side of the mask substrate B.
Since the entire back surface of the mask substrate mounting table 1 contacts the surface of the mask substrate mounting table 1, dust on the mask substrate mounting table 1 may adhere to the back surface of the mask substrate, or the back surface of the mask substrate may cause minute scratches due to contact with the surface of the mask substrate mounting table. There was a fear that I would be exposed to

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks of the mask substrate automatic inspection device of the separate application as described above, to be able to simultaneously inspect the back side of the mask substrate, and to eliminate the risk of dust adhering to the back side of the mask substrate or generation of minute scratches during the inspection. An object of the present invention is to provide a mask substrate double-sided inspection device.

[Summary of the invention]

The mask substrate double-sided inspection device according to the present invention has a supporting member that engages only the peripheral edge of the mask substrate to support the mask substrate, and a light projector that projects spot light onto different locations on both sides of the mask substrate. and a pair of television cameras arranged opposite to the spot light incident position on the mask substrate. - According to the apparatus of the present invention having such a configuration, both sides of the mask substrate can be automatically inspected at the same time, and there is no fear of dust adhesion or minute scratches occurring on the back side of the mask substrate during inspection.

Furthermore, in a preferred embodiment of the present invention, the apparatus is configured so that only the peripheral edge of the mask substrate contacts each part of the apparatus not only during the inspection but also before and after the inspection. There is no fear of dust adhering to both sides of the mask substrate or the generation of minute scratches, not only during the inspection, but also before and after the inspection. Therefore, according to the apparatus of the present invention, reliability can be improved in the manufacturing process of ICs, LSIs, etc. Can provide certain test data.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 2 to 6.

FIG. 2 diagrammatically shows the basic principle common to the first embodiment (FIGS. 6 to 5) and the second embodiment (FIG. 6) of the present invention, mainly related to detection and control. This figure shows the schematic configuration of . As shown in FIG. 2, in the apparatus of the present invention, the mask substrate B is supported by a support member 16 that engages only its peripheral edge, and this support member 16 is operated by a moving and positioning device 17 connected thereto. In the two directions, the direction perpendicular to the paper surface and the left and right direction parallel to the paper surface (
(parallel to the plate surface of the mask substrate). The moving and positioning device 17 includes a connecting member 18 connected directly or indirectly to the supporting member 16, and a driving device 19 connected to the other end of the connecting member 18.

The connecting member 18 can be, for example, a combination of a lead screw and a nut or a simple rod. Further, as the drive device 19, for example, a pulse motor or a hydraulic cylinder device capable of minute feeding is used. (
Since the moving/positioning device 17 needs to be provided for each direction of movement of the support member 16, the actual device is equipped with a pair of moving/positioning devices 17, but only one is shown in FIG.

A movement and positioning control device 20 for electrically controlling the drive device 19 is electrically connected to the drive device 19, and as this control device 20, for example, an NC (numerical control) device or the like is used.

Floodlights 21 and 22 and television cameras 23 and 24 are provided on both sides of the mask substrate B held by the support member 16, respectively.
(may be one projector using a -7 mirror), and the incident points of the light beams projected onto both sides of the mask substrate B from the projectors 21 and 22 are monitored by the respective television cameras 26 and 24. It is supposed to be done. The respective arrangement positions of the projectors 21 and 22 are different so that the incident points P1 and P2 of the light projected onto the mask substrate B from the projectors 21 and 22 are different from each other on both sides of the mask substrate. 26 and 24 are also installed at different positions (positions not facing each other) toward the respective incident points P□ and P2. Camera controllers 25 and 26 are electrically connected to each television camera 26 and 24, respectively, and the camera controllers 25 and 26 are connected to a main controller 27 along with a movement and positioning controller 20.
electrically connected to. The main controller 27 also includes:
Position detector 2 for detecting the moving position of the support member 16
8 are electrically connected, and the output signal of the position detector 28 is applied thereto. For example, a laser interference type detector may be used as the position detector, but if feedback is not required, the position detector 28 may not be provided.

The main control device 27 is a device such as a minicomputer having a calculation function and a storage function, and is connected to an input device 29 such as a keyboard or a tape reader, as well as an output device such as a printer.

and two television receivers 31, also serving as output devices.
32 etc. are connected. This TV receiver 31.62
are for displaying the output signals of the television cameras 23 and 24 as images, and serve as monitors for monitoring the surface condition of each surface of the mask substrate B.

6 to 5 show a first embodiment of the apparatus of the present invention shown in FIG. 2, and particularly show the main structure of a double-sided mask substrate inspection apparatus of a type in which the mask substrate B't is horizontally supported. It is something that In this embodiment, a pair of supporting members 36 are attached to the first slide 34, holding only the side edges of the mask substrate B, so that the mask substrate B is held by the supporting members 33. It has become. The support member 66 is movable relative to the first slide 64 in the direction of arrow a in FIG. 4 by means of an air cylinder or solenoid fixed to the first slide 64. The support member 66 constitutes a gripping device for gripping the mask substrate B. The tip portion 33a of the support member 63 is made of a flexible material such as rubber so as to engage with the side edge of the mask substrate BO, and a recess is formed in the tip portion corresponding to the side edge of the mask substrate. There is.

A nut 65 is fixed to the first slide 64 so that it can only rotate, and as shown in FIG. 6, a feed screw 66 driven by a pulse motor 67 is screwed into the nut. The first slide 64 can be moved in the direction of the arrow in FIGS. 6 and 4. The feed screw 66 is rotatably supported by a fixed frame (not shown). The first slide slide 64 is divided into two parts separated by the mask substrate B't, and both parts are separated by a pair of connecting arms (only one of which is shown in FIG. 5) that bypasses the mask substrate B. They are mutually VC-connected by A) and can move together as one. A second slide 38, which has a guide on the top surface for guiding the first slide 34 in the direction of the arrow, is connected to the first slide 6.
This second slide 68 also supports the sixth slide.
As seen in FIGS. 5 to 5, a pair of connecting arms 68A (only one of which is shown in FIG. 5) is divided into two parts with the mask substrate B in between and bypasses the mask substrate B. Both subcommittees are integrally connected.

This second slide 68 is a frame 6 divided into left and right parts.
9 and can be moved in the direction of arrow C in FIG. 6 along guides 39a on the frame. A nut 40 (see FIG. 4), which is attached to the second slide 58 so that it can rotate only by K, is threaded onto a feed screw 41, and the feed screw 41 is connected to be rotated by a pulse motor 42. This feed and screw 41 are connected to the frame 69
It is supported so that it can only be rotated.

The two pulse motors 37 and 42 for driving the first and second slides 64 and 68, respectively, are controlled by the control device 20 described above.

At the upper and lower positions of the frame 69, projectors 21 and 22 and a television camera 2 are installed facing both sides of the mask substrate B.
These projectors 21 and 22 and television cameras 26 and 24 are arranged facing different positions on the mask substrate B, as previously explained in FIG. 2. .

Between the pair of support members 66 that grip both side lines of the mask substrate B, from above and below in FIGS. 3 and 5,
The loader 46 and the unloader 44 can enter as shown by arrows d and e, and the mask substrate before inspection is mounted on the loader 46 and supplied between both supporting members 66, and the mask substrate after inspection is carried by the unloader 44. It is taken out from between both support members 63 by. In this case, the loader 43 and the unloader 44 move up and down between the support members 63, and the mask substrate is transferred between the support members 66. The mask substrate is transferred by moving forward and backward to grip or release the mask substrate.

(The schematic control system of the first embodiment shown in FIGS. 3 to 5 is as shown in FIG. 2, but the control system related to the loader and unloader is omitted in FIG. 2, 11C.) In the second embodiment shown in FIG. 6, each part of the apparatus is constructed in accordance with a more rational mask substrate handling method than in the first embodiment shown in FIGS. 6 to 5.

That is, in the embodiment shown in FIG. 6, the mask substrate is held only at its peripheral edge during the inspection and before and after the inspection, and is always held in a vertical state. It can effectively prevent the occurrence of small scratches. Further, the device has the advantage that the area occupied by the device is small and the mechanism for receiving and transferring the mask substrate is simple.

In FIG. 6, numeral 45 is an uninspected product storage cassette that stores mask substrates Bt before inspection, and this uninspected product storage cassette 45 is designed to store a large number of mask substrates B in an upright state. The top plate 46 and the bottom plate 47 are provided with a large number of parallel mask substrate storage grooves, and the top plate 46 is connected to the bottom plate 47.
It is mounted on several pillars 48 erected above. The bottom plate 47 is fixed on a slide 49 that can move in a direction perpendicular to the respective mask substrate storage grooves of the top plate 46 and the bottom plate 47, and the slide 49 is configured to move the mask substrate by a feed device composed of a feed screw 50 and a pulse motor 51. It is intermittently fed in a direction perpendicular to the surface of the substrate B by a constant distance. Behind the uninspected product storage cassette 45 (
That is, in the left position in FIG. 6), there is installed an extrusion device 56 for feeding uninspected mask substrates Bt one by one from the uninspected product storage cassette 45 to the inspection apparatus main body 52.

This extrusion device 56 has a cylinder 5 fixed at a predetermined position.
4 and a mask substrate engaging member 56 fixed to the tip of the rod 55 of the cylinder, and the cylinder 54 is operated in synchronization with the movement of the slide 49. This extrusion device 53 and the cassette 45 constitute a so-called mouth.

A first connection rail 57 that is stationary with respect to the cassette 45 is arranged on the front side of the uninspected product storage cassette 45, that is, on the right side in FIG. A single groove is provided that aligns with the storage groove. This connecting rail 57 serves as a guide for passing the mask substrate B pushed out by the extrusion device 53 from the uninspected product storage cassette 45 to the inspection device main body 52, and every time the slide 49 is sent in the direction of the arrow shown in the figure. is aligned with one of the mask substrate storage grooves in the uninspected product storage cassette 45.

The inspection device main body 52 disposed adjacent to the first connection rail 57 includes a first slide 58 that also serves as a mask substrate support member, and a second slide 58 that supports the first slide 58 and is movable in the vertical direction. It has a slide 59. The first slide 58 is provided with a groove 58a (FIG. 7) on its upper surface that is aligned with the groove of the first connecting lever 57, and this groove 58a
It has a pillar 60 erected on the side, and an engagement piece 61 that engages only with the upper edge of the mask substrate is provided at the top end of the pillar 60. As shown in FIG. 7, a groove 61a parallel to the groove 58a on the slide 58 is provided at the lower end of the retaining piece 61 so as to pass through the groove 61a.
The upper edge of the can pass through. The first slide 58 is screwed into a feed screw 62 disposed parallel to the groove 58a thereon, and rotates along the axis of the feed screw 62 in accordance with the rotation of a pulse motor 66 connected to the feed screw 62. It moves me.

The first slide 58 includes a supporting second slide 59
There is a guide groove 59a for guiding the first slide 58.
is provided on its upper surface and is screwed into a feed screw 64 extending in the vertical direction. A pulse motor 65 is connected to the feed screw 64, and as the pulse motor 65 rotates, the second slide 59 is moved up and down along the axis of the feed screw 64. In order to move the second slide 59 up and down accurately and smoothly, a guide bar 66 erected on a fixed frame (not shown) guides the second slide 59'fr.

Projectors 21 and 22 and television cameras 23 and 24 are arranged in pairs in the inspection device main body 52, facing both sides of the mask substrate B on the first slide 58, respectively.
These positional relationships are the same as in FIG.

The first connection rail 5 is located on the right side of the inspection device main body 52.
A second connection rail 67 having the same structure as 7 is arranged, and a good product storage cassette 68 and a defective product storage cassette 69 are arranged in parallel adjacent to the second connection rail 67 on the right side. These double-sided sets 68 and 69 have exactly the same structure as the uninspected product storage cassette 45, and have top plates 70 and 71 and bottom plates 72 and 76, respectively, each having parallel mask substrate storage grooves. 70 and 71
It has pillars 74 and 75 that support it. Furthermore, although the double force sets 68 and 69 have separate slides 76 and 77, since both slides 76 and 77 are screwed together with a common feed screw 78, the pulse motor connected to the feed screw 78 Both cassettes depending on the rotation of 79) 68.69
68. At the rear of 69, that is, at the right position in FIG. 6, are the cylinder 81 and the tip of the cylinder 810 and rod 82. A take-out device 80 is provided which includes a gripping member 86 provided at the top, and this take-out device 80 and the above-mentioned double force set 68 and 69 constitute an unloader.

The gripping member 86 of the extraction device 80 has a pair of fingers that softly grip the edge of the mask substrate B, and these fingers are pivotally attached at their base ends, and their tips can move forward and backward relative to each other. It is composed of

The operation of the apparatus shown in FIG. 6 having the above structure will be briefly explained below.

When inspecting the uninspected mask substrate B stored in the uninspected product storage cassette 45, the slide 49 of the cassette 45 is intermittently fed in the direction of the arrow by the pulse motor 51 and the feed screw 50. The slide 49 is positioned so that one of the uninspected mask substrates B therein is aligned with the connection rail 57. After the slide 49 has stopped, when the extrusion device 56 and the cylinder s4d are activated, the uninspected mask substrate B is moved from the inside of the cassette 45 to the connecting rail 57 by the mask substrate engaging member 56 at the tip of the rod 55.
It is pushed upward, passes over the connection rail 57, and is transferred onto the first slide 58 of the inspection and preparation section main body 52. In this case, the upper edge of the mask substrate is located at the first slide 58.
After entering the groove 61a of the retaining piece 61 provided on the upper pillar 60, the mask substrate engaging member 56 is retracted by the cylinder 54 of the extrusion device 56, so that the mask substrate to be inspected is placed on the first slide 58. Only B is left. Then, the pulse motors 66 and 65 are driven to move the first slide 58.
and the second slide 59 are connected to the feed screws 62 and 6, respectively.
As a result, the spot lights projected onto the mask substrate B from the projectors 21 and 22 sequentially scan the surface of the mask substrate B, and the state on the mask substrate is continuously It is projected onto a television receiver 31, 32 (Fig. 2). On the other hand, in this case, the surface condition of the mask substrate and the scanning position of the spot light are output as a print record by a printer or the like of the output device 60.

After the inspection, if the main controller 27 automatically determines that the mask substrate is a good product, the pulse motor 79
and the good product storage cassette 68 by the operation of the feed 9 screw 78.
The slide 76 is positioned such that one of the mask substrate storage grooves is aligned with the connection rail 67. Next, the cylinder 81 of the take-out device 80 is activated, and the gripping member 86 at the tip of the rod 82 advances onto the first slide 58, and the pair of fingers of the gripping member 86 grips the side of the mask substrate on the first slide 58. The edges are gripped. After gripping the mask substrate, the cylinder 81 is moved, and the mask substrate gripped by the gripping member 83 is moved from the top of the first slide 58 to the connecting rail 67.
It passes through and is drawn into the good product storage cassette 68. As described above, the mask substrate after inspection is placed in the non-defective storage cassette 6.
8, the gripping member 83 releases the mask substrate, and the cylinder 81 further pulls the gripping member 83 out of the cassette 68.

In this way, in the device of the second embodiment, of course, during inspection,
Since the mask substrate is maintained vertically before and after the inspection, problems such as dust adhesion and scratches do not occur.

As described above, according to the present invention, both sides of a mark substrate can be automatically inspected at the same time, and the automatic inspection can be performed not only on the front side of the mask substrate but also on the back side without fear of dust adhesion or scratches. A mask substrate double-sided inspection device is obtained.

Although the illustrated embodiment shows an apparatus having a structure in which the mask substrate is moved relative to the projector and the television camera, a structure may be adopted in which the mask substrate is fixed and the projector and the television camera are moved.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a mask substrate single-sided inspection device of a separate application, Figure 2 is a conceptual diagram of a mask substrate double-sided inspection device of the present invention, and Figure 6 is a schematic diagram of a mask substrate double-sided inspection device of the present invention.
Figures 5 to 5 are schematic diagrams of the main parts of the first embodiment of the present invention.
5 and 5 are plan views, FIG. 4 is a sectional view along the TV-IV arrow in FIG. 5, FIG. 6 is a perspective view of the second embodiment of the present invention, and FIG.
The figure is a cross-sectional view of a portion of FIG. 6. B...Mask substrate, 16.67)L (ssj'/book support member, 20...Movement and positioning control device, 34,
38,49,58,59,76°77...slide,
27... Main control device, 21.22... Floodlight, 23
．． 24...TV camera, 31,62...TV receiver, 36,41.50,62,64.78...Feed screw, 37,42,51. 63.65,79... Pulse motor, 45... Uninspected product storage cassette, 68... Good product storage cassette, 69
... Defective product storage cassette, 56 ... Extrusion device, 80
...Take-out device. Patent applicant Tokyo Shibaura Electric Co., Ltd. Figure 1 Figure 92 Figure 3 Figure 4

Claims (1)

[Claims] 1. A support member that engages only the peripheral edge of a mask substrate used for lithography to support the mask substrate, and a support member that moves the mask substrate parallel to the plate surface through the support member. A moving/positioning device for positioning, a projector disposed on both sides of the mask substrate for projecting spot light onto different positions on each plate surface of the mask substrate, and a positioning device for adjusting the incident position of the spot light onto the mask substrate. A pair of television cameras placed on opposite sides of the mask substrate and the moving and positioning device are controlled to scan the entire surface of the mask substrate with the spot light and control the television cameras. A mask substrate double-sided inspection device including a control device, a television receiver connected to the main control device, an input device, and an output device. 2. The mask according to claim 1, which includes a loader that automatically feeds the mask substrate before inspection to the support member, and an unloader that automatically takes out the mask substrate after inspection by the force of the support member. Double-sided board inspection equipment. 6. The mask substrate double-sided inspection apparatus according to claim 1, wherein the support member is configured to support the mask substrate with the surface of the mask substrate facing up and down. 4. The mask substrate double-sided inspection apparatus according to claim 1, wherein the support member is configured to vertically support the mask substrate. 5. Claim 2, wherein the supporting member, the loader, and the unloader are configured to support and move the mask substrate in a vertical position, and the unloader has a defective product sorting function. The mask substrate double-sided inspection device described above.