JP2568272B2 - Glass substrate carrier - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass substrate transfer apparatus, and more particularly to an apparatus for conveniently transferring a mask or reticle in a semiconductor exposure apparatus.

[Conventional technology]

One of the problems to be solved in manufacturing semiconductor devices such as ICs, LSIs, and VLSIs is the problem of dust adhesion to a mask or reticle. When transferring the ultra-fine circuit pattern formed on the mask to the wafer, if dust is attached to the mask, the circuit pattern transferred to the wafer will be damaged, and LSI etc. that have been commercialized through post-processes Not only does the performance of the semiconductor device deteriorate, but in the worst case, the entire function of the semiconductor device is impaired.

However, in the conventional semiconductor manufacturing apparatus, a worker must directly load the mask or reticle into the mask holder by hand, and therefore dust from a human body is likely to adhere to the mask or reticle. Further, as the diameter of the mask has increased in recent years, it has become difficult to handle by hand, and there is a risk of scratching or damage to the mask due to careless handling by an operator.

Therefore, in order to solve such a problem, some automatic transfer devices for masks or reticles (hereinafter referred to as masks) have been developed and used.

In these automatic transfer devices, when the mask is transferred to a stage on the transfer destination device, it is necessary to deliver the mask between at least two stages. The at least two stages referred to here are, for example, in a semiconductor manufacturing apparatus, a pre-alignment stage and an exposure position stage. The conventional apparatus is mainly composed of a first transfer unit that transfers between the storage position and the pre-alignment stage, a pre-alignment stage, and a second transfer unit that transfers between the exposure position stage. there were. Such delivery is often performed by vacuum suction of the mask surface. This mask vacuum suction method is often provided by molding rubber or resin into a suction cup shape, but these materials deteriorate or
Since it is easy to cause dust by scraping,
A metal suction cup is desirable.

However, since a metal sucker has almost no elasticity, a vacuum leak (hereinafter referred to as a VAC leak) occurs if the sucker surface is slightly inclined with respect to the object to be adsorbed, and therefore it is necessary to support the elastic body.

The supporting means cannot improve the transport accuracy unless it has a structure that has elasticity in the vertical direction and is constrained in the horizontal direction. For this reason, a coil spring or the like having elasticity in the lateral direction is not desirable, and a leaf spring that does not allow a large amount of vertical deflection is often used because it is lowered.

Further, the mask hand often has a structure that also serves as a positioning mechanism when the mask is positioned.

[Problems that the invention is trying to solve]

However, in the above conventional example, 1) the second mask used for transferring the mask between stages
The stop position at the time of descending for checking the transport means of
Since it is performed with reference to the sensor in the drive mechanism section in the mounting section of the second transport means, if there are several stop positions,
The number of sensors required for the stop position was required.

In addition, even if the pulse motor drive is used and the stop position is determined by the number of pulses sent, the vertical stroke of the suction cup is small, so the required number of drive pulses will vary from unit to unit unless the distance accuracy between stages is severe. There must be.

When the mask thickness is further changed, it is necessary to input the mask thickness for each sheet or to adjust the position of the stop position sensor for each sheet.

2) The metal sucker for avoiding foreign matter attached to the mask is
It must have a sinking mechanism at the stop position for adsorption. In the conventional example, in the leaf spring used here, when the sinking stroke becomes large, the suction surface is tilted (Figs. 9 and 10) and rotated (Figs. 11 and 12).
(Fig.), Which caused a VAC leak.

3) Since the mask is positioned with reference to the second carrying means (hand), the stopping accuracy for carrying is added to the positioning accuracy, and it is disadvantageous in terms of weight.

Therefore, it is difficult for the conventional apparatus as described above to accurately transfer the glass substrate between the two stages.

The present invention has been made in view of such circumstances,
An object of the present invention is to provide a glass substrate transfer device that can accurately transfer a glass substrate in a glass substrate transfer device that transfers a glass substrate taken out from a dustproof container to a desired position via a temporary positioning stage. .

[Means and Actions for Solving Problems]

In order to achieve the above-mentioned object, the present invention is a glass substrate carrying device for carrying a glass substrate taken out from a dustproof container to a desired position through a temporary positioning stage, wherein the glass substrate pulled out from the dustproof container is used. It comprises a first transporting means for transporting to the vicinity of the temporary positioning stage, and a second transporting means for holding the glass substrate passing through the temporary positioning stage with a hand and transporting the glass substrate to a desired position, wherein the second transporting means is A metal suction cup for sucking a glass substrate, a support mechanism for supporting the suction cup with elasticity in the vertical direction and a binding force in the horizontal direction with respect to the hand, and the glass of the hand A distance detection mechanism for detecting a distance to the substrate surface, and a drive mechanism for raising or lowering the hand relative to the glass substrate. It is.

Further, the drive mechanism stops the descent of the hand toward the glass substrate according to the detection output of the distance detection mechanism, or the second transfer means is at a desired position from the temporary positioning stage. The glass substrate is held by the suction cups and conveyed to the next stage, or the second conveying means has a pressing mechanism for pressing the glass substrate to a positioning reference on the hand. Is provided only on the temporary positioning stage, or the support mechanism has a structure that does not tilt the suction cup with respect to the hand even when it is bent in the vertical direction.

As described above, it is possible to accurately detect the descending stop position of the second transfer means even with respect to the change in the mask thickness and the vertical position of the stage with time, and the positioning reference provided at the final transfer destination. By pressing the mask against, it is possible to ignore the transport error that occurs during transport.

In addition, if the suction plate is one that tilts and rotates when it sinks, the suction plate will sink because the amount of tilt and rotation is fixed by vacuum (VAC) suction after sinking. It remains as it is, and the amount of subduction is also saved. However, by using a leaf spring (FIG. 3) that does not tilt or rotate when it is submerged, the second conveying means is provided by a mechanism for detecting the distance to the mask surface provided on the second conveying means. The descending stop position of can be accurately indexed.

〔Example〕

(I) FIG. 1 is a perspective view showing a schematic configuration of an automatic mask carrier according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a mask transferred between stages in the automatic carrier. It is sectional drawing of a frog mechanism.

In FIG. 1, 1 is a dust-proof cassette for containing the mask 13, 2 is a cassette carrier for containing the dust-proof cassette, 3
Is a fork that draws out the upper pig that constitutes the dust-proof cassette and the mask that contains only the lower plate of the lower plate inside,
Horizontally driven by 30 DC motors in the direction of the cassette carrier. 4 is an elevator for moving the fork portion up and down by a DC motor (not shown), 5 is an index plate used for indexing the vertical position of the elevator, 6 is a light quantity switch for reading the shape of the index plate, and 7 is a mask between each stage. The mask hand is moved, and is driven in a vertical direction and a rotation direction by a motor (not shown). Reference numeral 8 denotes a PA stage that temporarily positions the mask, and is driven by the cylinder 31 in the same horizontal direction as the direction in which the fork moves. Reference numerals 16 to 19 denote rollers that are pressed against the mask to temporarily position the x, y, and θ positions. The details are shown in FIG. 9 is a metal sucker for vacuum-adsorbing the mask, 10
22 is a mask surface sensor driving unit for detecting the distance between the mask surface and the mask hand, and 11 is a mask pressing mechanism.
Is driven to rotate about an axis parallel to the ridge of the mask. Reference numeral 12 is on the loader mechanism of 15, and 15 is a mask chuck for adsorbing and moving the mask up to the exposure stage (not shown). A hole for optically transferring the mask pattern onto the wafer is formed in the center. I am open. Reference numeral 13 is a mask chucked onto the mask chuck by vacuum suction, and reference numeral 14 is a reference roller provided on the mask chuck for positioning the mask. The 14 mask checks are moved from the position shown to the exposure position by the 15 mask loader. In FIG. 2, 20 is a light-shielding plate driven by movement of 10, 21 is a photoelectric switch whose optical path is opened and closed by 20, and 22 is an air cylinder for rotationally driving the mask pressing portion. In the figure, 23 is a leaf spring that supports a metal suction cup. 5 to 7 are schematic diagrams showing changes in state when the second conveying means indexes the lowering stop position, and FIG. 8 shows a flow chart of a main part. Further, FIGS. 9 to 12 are examples of suction plates that cause tilting and rotation due to sinking, and FIG. 13 is a detailed view of the pressing roller (16 to 18) part shown in FIG. is there.

(II) In the above structure, the operation will be described with reference to FIGS. 1 and 2 and other drawings. Fork 3 in Figure 1
Is driven in the horizontal direction by a motor 30, and the lower tray of the dustproof cassette is pulled out together with the mask from the cassette carrier 2, raised to a fixed position, and stopped by a photo sensor (not shown). In the mask PA stage 8, the hand 7 is the mask 13
In order to open a path for adsorbing and advancing, the cylinder 31 is once driven to move backward in the horizontal direction. Here, since a simple flow chart of each operation is shown in FIG. 8, description will be added while correspondingly. This flow chart is sequentially executed by a program of a microcomputer (not shown) connected to the outside of the apparatus. Mask hand 7
Is rotationally driven and is stopped vertically above the forks 3, but is driven vertically downward from this state by a DC motor (not shown) (FIG. 8). After that, in FIG. 2, the mask surface sensor driving unit 10 contacts the mask 13, and the light shielding plate 20 turns off the photoelectric switch 21. As shown in FIG. 8, the photoelectric switch 21 is being monitored while the mask hand 7 is descending, and the sequence proceeds at the same time when the photoelectric switch 21 is turned on. At this time, since the suction cup 9 is supported by the leaf spring 23 shown in FIG. 3, even if the mask 13 is slightly out of parallel with the mask hand 7, it can be depressed to absorb the deviation (FIG. 2). ). When the photoelectric switch 21 detects a signal from the light-transmitting state to the light-blocking state, the descending of the mask hand is stopped by issuing a stop command to a motor (not shown) from a microcomputer (not shown).
(FIG. 8) to suck the mask 13 and then raise the mask hand 7 (FIG. 8).

The relative movements of the mask hand 7, the suction cup 9, the mask surface sensor driving unit 10, and the mask 13 will be described with reference to the schematic diagrams of FIGS. 5 to 7.

When the mask hand 7 descends or the mask 13 rises from the state of FIG. 5, the mask surface detection sensor 10 is pushed up, and the suction cup 9 comes into contact with the mask 13 so that the suction cup surface and the mask 13 are parallel to each other. Abnormality is absorbed. This state corresponds to the state shown in the middle of FIG. But at this time,
Since the arrow is above the switching point of the signal with a circle, it has not been detected.

When the mask hand is further lowered by δ, the drive unit 10 of the mask surface sensor is pushed up as shown in FIG. 7, and the detection unit 24 is changed to the ON state. In the present embodiment, as shown in FIG. 2, when the driving unit 10 of the mask surface sensor is pushed up, the light shielding plate 20 is rotated by the shaft provided at the center, and the photoelectric sensor 21 is turned on. . Although the mask pressing roller 11 provided on the mask hand 7 is drawn in a pressed state, it is rotated by the cylinder 22 and extended in the horizontal direction at the time of suction.

As described above, when the mask surface sensor is turned on, the hand immediately stops descending and the VAC of the suction cup 9 is turned on. Next, when the hand 7 is raised (FIG. 8), the mask 13 is raised because it is vacuum-sucked by the hand 7. When the leaf spring returns to this rise and the distance between the hand and the mask is separated to the regular position, the drive unit 10 of the mask surface sensor is also lowered and the mask surface sensor is also turned off.

When the hand cuts the upper limit switch (not shown) and stops driving, the PA station 8 descends backward in the horizontal direction and is retracted from the ascending / descending path of the hand, but the mask held by the hand 7 moves forward. It is driven by the cylinder 31 up to the vertical underline (Fig. 8). At this time, the photoelectric sensor 21 serving as the mask surface sensor is turned off as described above, which is confirmed in FIG.
This is because when the leaf spring 23 raises the mask hand 7 and the photoelectric sensor 21 of the mask surface sensor is not turned off by any chance, the mask hand 7 shown in FIG.
This is done at the same time as the descent of the above starts, and the mask is dropped to the PA station 8. This is a safety confirmation to prevent this.

After the safety confirmation is performed, the hand 7 descends again and the mask 13 contacts the PA station 8. By the contact between the mask 13 and the PA station 13, the mask is lifted relative to the hand 7, and the mask surface sensor 21 becomes OF.
Switch from F state to ON state.

At the same time when the output of the mask surface sensor 21 is turned on, the hand descent drive motor (not shown) stops rotating and the suction cup 9
Turn off the VAC. The hand is again raised to the upper limit switch (not shown) (Fig. 8), and the mask is temporarily positioned on the PA station 8 (Fig. 8).
First, the reference rollers 16 and 17 are driven toward the center of the PA station 8. A stopper is provided in this drive path, and the drive of the reference roller is stopped at a fixed position.

After that, the pressing side rollers 18 and 19 are driven to position the mask in the x and y directions.

Further, the reference roller 16 is composed of two pieces, and the θ of the mask can be positioned.

Details of the above parts will be described with reference to FIG. In FIG. 13, 33a to 33d are air cylinders for driving the pressing arms 35a to 35d, respectively. Pressing roller 16-19
Are rotatably fixed on the pressing arms 35a-d. The supports 36a to 36d are the PA stage 8 (Fig. 1).
And the air cylinders 33a to 33d are held as shown. Pins 38a, 38d for restricting the amount of movement of the rollers 16, 17 supported by the pressing arms 35c, 35d in the central direction 0 are fixed to the support bases 36c, 36d. The rollers 16 and 17 regulated by the 38a and 38d serve as a reference for centering the mask 13 (depicted as a circle in the figure). The roller 18 moves the mask 13 in the X direction,
That is, pressing the mask 13 in the direction of contacting the roller 17,
The roller 19 presses the mask 13 in the Y direction, that is, in the direction of bringing the mask 13 into contact with the roller 16. When the cylinders 33a and 33b move the arms 35a and 35b in the direction of the center 0, the cylinders 3a and 33b support the rollers 18 and 19, respectively.
Springs 37a, 37b that generate a biasing force against the pressing force of 3a, 33b
Is installed. As a result, when the mask 13 is centered, the rollers 19 and 18 are pressed by the rollers 16 and
It is lower than the mask pressing force of 17. This is because if the pressing force of the four rollers is equal, the pressing force will be balanced even before the arms 35c, 35d contact the pins 38a, 38d, and the centering of the mask 13 will be inaccurate. This is to prevent this.

60a, 60b are control valves for controlling the air from the air supply source 61, and the control valve 60a simultaneously controls the movement of the rollers 16, 17 via the cylinders 33c, 33b. The control valves 60a and 60b are used as the reference rollers 16 and 17 when the mask 13 is centered.
The rollers 18 and 19 for contacting the peripheral edges of the mask 13 with the reference rollers 16 and 17 are provided so as to be independently controllable. Cylinder after centering
When the supply air to 33a ~ 33d is cut off at the same time, due to the influence of frictional force etc., the reference rollers 16 and 17 separate from the mask 13 earlier than the pressing rollers 18 and 19, and the mask 13 once positioned is moved. This is to prevent it from being lost. If the mask 13 is rectangular, any one of the reference rollers 16 and 17 may be used so that θ does not occur. Further, at the time of this positioning, air passing through the filter is supplied to the contact portion 32 of the PA station 8 with respect to the mask 13 so that the mask is floated by a small amount to reduce sliding between the mask and the mask receiver. Is desirable.

After the x, y, θ plate positioning of the mask is completed, the hand 7 descends again, and after adsorbing the mask and ascending according to the procedure described so far (from FIG. 8), it rotates to rotate the mask loader 15. Rotate to the top of the mask chuck 14 placed on top. After that, the mask hand 7 descends while adsorbing the mask, and descends the mask onto the mask chuck 12. The above-mentioned sequence is executed again (FIG. 8), and the suction cup 9
VAC is turned off and the hand 7 is raised. At this time, the amount of rise of the mask hand is determined to be a constant amount from the moment the mask surface sensor 21 is turned from ON to OFF. In order to perform this drive, it is desirable to use a pulse motor as the drive source of the hand 7, but it is possible to determine a drive time by a DC motor and perform a fixed amount of drive.

The hand rises above the position where it hits the mask chuck 12 before the pressing roller 11 rotates and contacts the mask, and then the pressing roller 11 is driven to rotate by the cylinder 22 and the mask is placed on the mask chuck as a reference of three. By pressing the roller 14 again, final positioning is performed with respect to the outer shape reference (FIG. 8).
Therefore, a transport error that occurs during mask transport, that is, a shift when the hand 7 picks up the mask 13 and a variation in the rotation angle of the hand are canceled, and high positioning accuracy can be ensured for the mask chuck. After this, the mask hand rises (FIG. 8) and the supply operation is terminated.

In addition, the leaf spring 23 supporting the metal suction cup 9 has a radial shape so that the rotation and inclination generated by the depression are canceled, and the rotation in the circumferential direction is canceled. It is necessary.

In this embodiment, a leaf spring as shown in FIG. 3 was prepared by etching and used. The leaf spring 23 is designed to have elasticity in the central portion with respect to the circumferential portion in the normal direction to the paper surface, and has high rigidity in the direction parallel to the paper surface. The feature of this leaf spring is that the shape of the four support parts for connecting the central part to the circumferential part has a V shape, and the connecting part to the circumferential part is The connecting portion to the central portion is shifted from the same radiation from the center so that the two straight portions of the V shape have the same length. As a result, even if the center part bends with respect to the circumferential part, the waist part of the "<" shape rotates clockwise,
The central portion does not rotate with respect to the peripheral portion. The metal sucker (FIG. 4) assembled by using the leaf spring 23 having such a shape does not require a guide portion for sinking, and therefore a particle generated by sliding or rolling contact with the guide portion. Does not occur at all.

[Other Examples]

In this embodiment, the hand is always lowered to the suction position of the mask, but the mask may be sucked onto the hand by moving each stage up and down without moving the hand up and down.

Further, the light shielding plate for detecting the mask surface has a mechanism independent of the suction cup, but may be attached to the suction cup.

〔The invention's effect〕

As described above, a metal suction cup supported by a leaf spring that does not rotate or tilt due to sinking in the hand 7,
By providing a sensor for detecting the distance between the surface of the mask and the hand, (a) even if the thickness of the mask varies, dust generation can be suppressed and the conveyance can be performed reliably.

(B) The descending stop position can be accurately detected regardless of whether the mask is held by suction.

(C) Even if there are multiple stages to replace the mask, only one sensor is required to detect the stop position, and at the same time,
It is not necessary to adjust the stop position even with respect to position changes in the height direction of individual stages and assembling errors.

(D) Since the hand has a pressing mechanism for positioning the mask and presses against the standard set at the final destination of conveyance, the allowable range for hand assembly error and play adjustment should be large. You can

[Brief description of drawings]

1 is a perspective view of the entire automatic carrier, FIG. 2 is a sectional view of a mask hand for transferring the mask between stages in FIG. 1, FIG. 3 is a shape of a leaf spring supporting a suction cup, and FIG. Is a cross-sectional view of the suction cup, FIG. 5 is a schematic view showing a state where the mask hand is descending toward the mask, and FIG. 6 is a schematic diagram showing a state where the mask is in contact with the suction cup of the hand and the suction cup is in close contact with the mask. FIG. 7 is a schematic diagram showing a state where the mask is in close contact with the suction cup of the hand and is depressed, and FIG. 8 is a flow chart showing the main part of the entire sequence. FIG. 9 shows an embodiment of a suction cup supported by a leaf spring that tilts due to depression, and FIG. 10 shows a tilt of a suction cup supported by a leaf spring that tilts due to depression. The figure shows an embodiment of a leaf spring that generates rotation due to depression, Fig. 12 shows an embodiment of a suction cup supported by a leaf spring that causes rotation due to depression, and Fig. 13 shows temporary positioning of the mask. Plan view of the mechanism, 3 forks, 7 mask hand, 9 metal suction cup, 10
Is a mask surface sensor driving unit, 11 is a mask pressing mechanism, 14 is a reference, and 23 is a leaf spring supporting a metal suction cup.

Claims (5)

(57) [Claims] 1. A glass substrate carrying device for carrying a glass substrate taken out of a dustproof container to a desired position via a temporary positioning stage, and carrying the glass substrate pulled out from the dustproof container to a position near the temporary positioning stage. A metal for holding the glass substrate that has passed through the temporary positioning stage by a hand and transporting the glass substrate to a desired position by the second transporting means. Made of a suction cup, a support mechanism for supporting the suction cup with elasticity in the vertical direction and a binding force in the horizontal direction with respect to the hand, and a distance for detecting the distance of the hand to the glass substrate surface. A glass substrate transporting device having a detection mechanism and a drive mechanism for raising or lowering the hand relative to the glass substrate. 2. The apparatus for transporting a glass substrate according to claim 1, wherein the drive mechanism stops the descent of the hand toward the glass substrate according to the detection output of the distance detection mechanism. 3. The apparatus for transporting a glass substrate according to claim 1, wherein the second transport means suctions and holds the glass substrate from the temporary positioning stage to the next stage at a desired position by the suction cup. 4. The glass according to claim 1, wherein the second transfer means has a pressing mechanism for pressing the glass substrate as a positioning reference on the hand, and the positioning reference is provided only on the temporary positioning stage. Substrate transfer device. 5. The glass substrate carrying apparatus according to claim 1, wherein the support mechanism has a structure that does not tilt the suction cup with respect to the hand even when the support mechanism bends in the vertical direction.