JP4869612B2 - Substrate transport system and substrate transport method - Google Patents

Description

  The present invention relates to a substrate transfer system for transferring a substrate while levitating the substrate and a transfer method thereof.

  In recent years, with the increase in size of flat panel displays (FPDs) and the like, the glass substrates used for these displays have become large and thin, for example, with an area of 1500 mm × 1500 mm and a thickness of 0.5 mm. ing. When a substrate having such a shape is processed by a processing apparatus, the substrate is supported by the fork-shaped arm and the lower surface thereof is conveyed to the inside of the processing apparatus, so that the substrate warps due to contact with the arm. There was a problem.

  In order to solve this problem, a technique has been proposed in which a mechanism for blowing air from a perforation provided in a transfer stage for transferring a substrate is provided, and the substrate is transferred while being lifted by the air pressure (for example, Patent Document 1). reference.).

JP 2004-182378 A

  However, this transport method is a method of transporting a substrate at atmospheric pressure, and a method of transporting a substrate under reduced pressure has not been considered. Therefore, even if the substrate is transported in the air in a non-contact manner using a conventional transport method, the substrate and the arm are contacted when transported inside the processing apparatus under reduced pressure. . For this reason, the conventional transfer method has not yet solved the problem of warping of the substrate during transfer.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a substrate transfer system and a transfer method for transferring a substrate in a non-contact manner from atmospheric pressure to reduced pressure. It is in.

  In order to solve at least one of the above problems, according to an aspect of the present invention, a substrate is formed by injecting gas from a transport stage formed of a porous plate and a hole formed in the transport stage. There is provided a substrate transfer system including a levitation transfer device that transfers the substrate while floating.

  The levitation transfer device of this system is such that the pressure on the lower surface of the substrate and the pressure on the upper surface of the substrate have a certain relationship with respect to the substrate located in a predetermined container whose interior is depressurized from atmospheric pressure. Further, the substrate under reduced pressure is floated by controlling the gas injected into the lower surface of the substrate and the gas injected into the upper surface of the substrate.

  According to this, the substrate under reduced pressure can be levitated by controlling the gas injected into the lower surface of the substrate and the gas injected into the upper surface of the substrate. Accordingly, the substrate can be continuously levitated in the process of reducing the pressure in the processing vessel from the atmospheric pressure to the vacuum pressure in order to process the substrate floated and transferred under atmospheric pressure under reduced pressure. it can.

  Here, it is preferable that the gas entering and exiting under the reduced pressure is an inert gas. When the pressure on the lower surface of the substrate is P1 and the pressure on the upper surface is P2, the fact that the lower surface pressure P1 and the upper surface pressure P2 are in a certain relationship means a certain relationship in which P1> P2.

  The levitation transfer device may control the gas jetted into the lower surface of the substrate so that the pressure on the rear lower surface of the substrate is higher than the pressure on the front lower surface of the substrate in the transfer direction.

  According to this, by making the pressure on the rear lower surface of the substrate higher than the pressure on the front lower surface of the substrate in the transport direction, the front of the substrate is lowered from the rear of the substrate. As a result, the substrate is levitated and conveyed while being inclined forward with respect to the conveying direction under reduced pressure. As a result, the substrate can be continuously transferred in a non-contact manner in all substrate transfer processes from atmospheric pressure to a reduced pressure state. As a result, there is no need to transport the substrate by the arm. As a result, it is possible to avoid warping of the substrate during conveyance.

  In addition, since an arm for transporting the substrate is not necessary, the loading / unloading port of a container such as a load lock chamber can be made extremely small as compared with the conventional case. Thereby, containers, such as a load lock room, can be made very small. As a result, the exhaust volume is reduced, so that the interior of the container can be quickly evacuated even by inexpensive equipment such as an ejector. As a result, the tact time can be greatly shortened, and the productivity of the substrate can be improved.

  Further, the gas ejected to the substrate by the levitation transfer device may be clean hot dry air. According to this, the substrate can be transported while effectively removing moisture near the substrate. In particular, it is very important to remove moisture near the glass substrate for flat panel displays. Therefore, ejecting clean hot dry air is particularly effective when transporting a glass substrate for a flat panel display.

  Further, the transport stage includes an electromagnet and a magnetic body at a predetermined position, and the levitating transport device controls the current passed through the electromagnet when the substrate is positioned above the magnetic body. The substrate may be levitated by a repulsive force generated between an electromagnet and the magnetic body.

  According to this, the substrate can be magnetically levitated by the repulsive force generated between the electromagnet and the magnetic body by controlling the current applied to the electromagnet. As a result, the substrate can be levitated and conveyed by the levitating force caused by gas ejection and the repulsive force caused by magnetism. As a result, the risk of warping of the substrate during conveyance can be further reduced.

  According to another aspect of the present invention, from a atmospheric pressure to a reduced pressure state while the substrate is levitated using a conveyance stage formed of a porous plate and a levitating conveyance device that conveys the substrate while levitating. A method of transporting a substrate that is transported in a non-contact manner is provided.

  Specifically, the present transport method includes a step of floating the substrate by injecting a gas from a perforation formed in the transport stage, and a pressure on a rear lower surface of the substrate with respect to the transport direction. The step of transporting the substrate into a predetermined container by controlling the gas injected into the lower surface of the substrate to be higher than the pressure of the front lower surface, the step of depressurizing the inside of the container, and the depressurization Inert gas injected into the lower surface of the substrate and jetted onto the upper surface of the substrate so that the pressure on the lower surface of the substrate and the pressure on the upper surface of the substrate have a certain relationship with respect to the substrate located in the container A step of levitating the substrate under reduced pressure by controlling each of the inert gas to enter, and a pressure on the rear lower surface of the substrate higher than a pressure on the front lower surface of the substrate in the transport direction in front And a step of transporting the substrate under reduced pressure by controlling the inert gas inlet jet to the lower surface of the substrate.

  According to this, the substrate can be continuously transferred in a non-contact manner in all substrate transfer processes from atmospheric pressure to a reduced pressure state. As a result, it is possible to avoid warping of the substrate due to contact between the substrate and the arm. In addition, since an arm for transporting the substrate is not required, a container such as a load lock chamber can be made smaller, and as a result, the exhaust volume can be reduced. As a result, the interior of the container can be evacuated quickly even with inexpensive equipment such as an ejector. As a result, the tact time can be greatly shortened and the productivity of the substrate can be improved.

  As described above, according to the present invention, it is possible to provide a substrate transfer system and a transfer method for transferring a substrate in a non-contact manner from atmospheric pressure to reduced pressure.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
(Overview of transport system configuration)
First, an outline of the configuration of the substrate transfer system according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing a part of a transport system according to the present embodiment, and FIG. 2 is a plan view showing an outline of the transport system.

  The transfer system 10 is provided in a production line for transferring a substrate in order to process the substrate with a processing apparatus. In this embodiment, as an example of processing a substrate, a system for transporting the glass substrate 105 for plasma processing will be described as an example.

  As shown in FIG. 1, the transfer system 10 includes a transfer stage 100, and a plurality of air ejection devices 110 a and a plurality of air suction devices 110 b arranged in multiple stages below the transfer stage 100. .

  The transfer stage 100 is a table for transferring the glass substrate 105 while floating. The transfer stage 100 is composed of a porous plate 101 provided with a plurality of fine holes. A plurality of holes (perforations) provided in the porous plate 101 penetrate the porous plate 101 substantially perpendicularly to the transport surface.

  The transfer stage 100 is provided with an exhaust groove 102a and an exhaust groove 102b along the portion where the vicinity of both ends is located when the glass substrate 105 is transferred. Further, an exhaust port (not shown) is provided at the bottom of each exhaust groove 102, and the transport stage is connected to the transport stage 100 so as to be balanced with the air (gas) ejected from the perforations provided in the transport stage 100. The air near the outer periphery of 100 is discharged.

  A plurality of position sensors 103 a and 103 b for detecting the position of the glass substrate 105 are embedded at both ends of the transport stage 100, and the position of the glass substrate is specified by each position sensor 103.

  In addition, a plurality of air ejection devices 110a are arranged in multiple stages toward the conveyance direction on the lower left side of the conveyance stage 100 with respect to the conveyance direction. The plurality of air ejection devices 110a are configured to control the flow rate of air ejected from the perforations communicated with each of the air ejection devices 110a onto the upper surface of the transfer stage 100.

  In addition, a plurality of air suction devices 110b are arranged in multiple stages toward the transport direction below the right side of the transport stage 100 with respect to the transport direction. The plurality of air suction devices 110b are configured to control the flow rate of air sucked from the upper surface of the transfer stage 100 into the perforations communicated with each of the air suction devices 110b.

  As shown in FIG. 2, the transfer system 10 transfers the glass substrate 105 in the order of the load lock chamber 120, the process chamber 130, and the load lock chamber 140. The transfer stage 100 passes through a loading port 121, a loading port 122, a loading port 131, a loading port 132, a loading port 141, and a loading port 142 provided in the load lock chamber 120, the process chamber 130, and the load lock chamber 140, respectively. Yes. Each loading / unloading port is provided with valves 151 to 154 for opening and closing each loading / unloading port. Normally, the valves 151 to 154 are closed.

  The load lock chamber 120 and the load lock chamber 140 are installed to temporarily store the glass substrate 105 before the plasma processing in the process chamber 130 and after the processing. The process chamber 130 is an example of a processing apparatus, and the glass substrate 105 is processed by plasma generated in the process chamber 130, for example, an etching process, a CVD (Chemical Vapor Deposition) process, or the like. Is given.

(Outline of transport method)
Next, the outline of the transport method according to the present embodiment will be described with reference to FIG. 3 which is a cross section of the transport system 10 taken along the plane 1-1 of FIG.

  The plurality of air ejection devices 110a (air ejection devices 110a1, air ejection devices 110a2,...) Eject air from the perforations communicating with the air ejection devices onto the transfer stage 100. The plurality of air suction devices 110b sucks air on the transport stage 100 from the perforations communicating with the air suction devices.

  In this way, the glass substrate 105 moves the area A1 in the direction indicated by the arrow (by the cooperation between the air ejection devices 110a1, a2 and the like near the lower part of the transfer stage 100 where the glass substrate 105 is located and the air suction devices 110b1, b2 and the like ( It is conveyed while ascending toward the x-axis direction.

  When the glass substrate 105 is transported to just before the load lock chamber 120, the valve 151 is opened, the glass substrate 105 is transported into the load lock chamber 120 from the carry-in port 121, and then the valve 151 is closed.

  When the inside of the container is depressurized by evacuating the inside of the load lock chamber 120 using a vacuum pump (not shown) (for example, a dry pump), the valve 152 is opened and the glass substrate 105 is inhaled with the air ejection devices 110a10, 110a11 and the like. In cooperation with the apparatuses 110b10, 110b11, etc. (not shown), the wafer is transferred into the process chamber 130, placed on the mounting table 133, and the valve 152 is closed.

  The mounting table 133 is arranged to be movable up and down in the z-axis direction (height direction). In addition, the mounting table 133 is provided with a plurality of fine holes in the same manner as the transfer stage 100. The plurality of fine holes communicate with an air ejection device 110a21 provided below the mounting table 133 and an air suction device 110b21 (not shown). The air ejection device 110a21 and the air suction device 110b21 eject air from the perforations provided on the mounting table 133 onto the mounting table 133.

  When the inside of the process chamber 130 is evacuated using a vacuum pump (for example, a turbomolecular pump) (not shown) and the glass substrate 105 is subjected to plasma processing, the mounting table 133 is raised to a height suitable for the processing. . Further, when the glass substrate 105 is transported after the plasma processing, the mounting table 133 is lowered to a height near the transport stage 100. Thereafter, the valve 153 is opened, and the air ejection device 110a21, the air suction device 110b21, and the like float and convey the glass substrate 105 to the load lock chamber 140 by the air that is ejected from the pores communicating with these devices.

  When the glass substrate 105 is transferred into the load lock chamber 140, the valve 153 is closed and then the valve 154 is opened. In this way, the load lock chamber 140 is released from the reduced pressure state to the atmosphere. The air ejection device 110a40 and the like levitates and conveys the region A2 in the direction of the arrow (x-axis direction) by the air that is ejected from the holes communicating with these devices.

  In such a process, the region A1 and the region A2 are in the atmospheric pressure state, the region B1 and the region B2 are changed from the atmospheric pressure state to the reduced pressure state, and the region C is in the vacuum state. Therefore, the glass substrate 105 is levitated and conveyed under atmospheric pressure in the regions A1 to B1, and is levitated and conveyed under reduced pressure or vacuum in the regions B1 to C and B to B2, and again in the regions B2 to A2. It is levitated and conveyed under atmospheric pressure. In the following description, the air (gas) injected into the atmosphere is not limited to the type of gas, and may be air, for example. On the other hand, air (gas) injected under reduced pressure such as in the load lock chamber 120 or the process chamber 130 is inert gas (for example, for example) so as not to affect the processing when the processing gas is turned into plasma. Argon, helium) is preferable.

(Configuration of air ejection device and air suction device)
Next, the internal configuration of the air ejection device 110a and the air suction device 110b disposed in the region A1 or the region A2 will be described with reference to FIG. FIG. 4 shows a cross section of the transport system 10 taken along the plane 2-2 in FIG. The air ejection device 110 a is a device on the side that pressurizes the gas between the glass substrate 105 and the transfer stage 100. The air suction device 110 b is a device on the side for decompressing the gas between the glass substrate 105 and the transfer stage 100.

  The air ejection device 110a includes a pressure gauge 111a, a pressure control circuit 112a, an electropneumatic proportional control circuit 113a, an actuator 114a1, a valve 114a2, a pressure adjustment regulator 115a, a gauge 116a, a pressure switch 117a, a filter 118a, and a conduit 119a. . The air ejection device 110a is connected to a perforation for ejecting air onto the transfer stage 100 via a conduit 104a communicating with the conduit 119a.

  The pressure gauge 111a measures the pressure of the air in the conduit 104a corresponding to the pressure of the gas between the glass substrate 105 and the transfer stage 100 (on the higher pressure side than atmospheric pressure). The pressure gauge 111a is an example of a pressure sensor.

  The pressure control circuit 112a inputs an actual pressure value measured by the pressure gauge 111a and a control signal indicating a target pressurization value output from a computer (not shown), and a difference between the input actual pressure value and the target pressurization value. A pressurization signal (electric signal) indicating the value is output. The pressure control circuit 112a is built in, for example, a comparator that outputs a result of comparing two input values.

  The electropneumatic proportional control circuit 113a automatically controls the flow rate of air taken in from a compressed air line (not shown) corresponding to the pressurization signal. The electropneumatic proportional control circuit 113a is built in, for example, an electropneumatic regulator that converts an electrical signal into an air flow rate.

  The actuator 114a1 opens and closes the valve 114a2 based on the air flow rate automatically controlled by the electropneumatic proportional control circuit 113a. Specifically, the actuator 114a1 opens the valve 114a2 when air is input, adjusts the opening degree of the valve 114a2 according to the amount of air, and closes the valve 114a2 when no air is input.

  The pressure adjustment regulator 115a is connected to the conduit 119a and adjusts the pressure of clean hot dry air input to the conduit 119a. Clean hot dry air is high-quality air from which molecular contaminants (water) have been removed.

  The gauge 116a monitors whether or not the input clean hot dry air pressure is within a predetermined range, and the pressure switch 117a is an alarm when the input clean hot dry air pressure is outside the predetermined range. Is output. The filter 118a is a filter that removes dust in the air flowing in the conduit 119a.

  With such a configuration, the air ejection device 110a controls the flow rate of clean hot dry air that passes through the conduit 119a, thereby allowing air of a desired flow rate from the perforation of the transfer stage 100 via the conduit 104a communicating with the conduit 119a. Is supposed to spout.

  The air suction device 110b includes a pressure gauge 111b, a pressure control circuit 112b, an electropneumatic proportional control circuit 113b, an actuator 114b1, a valve 114b2, an electromagnetic valve 115b, an ejector 116b, and a conduit 117b. The air suction device 110b is connected to a hole for sucking air on the transfer stage 100 via a conduit 104b communicating with the conduit 117b.

  The pressure gauge 111b measures the pressure of the air in the conduit 104b corresponding to the pressure of the gas between the glass substrate 105 and the transfer stage 100 (at a lower pressure side than the atmospheric pressure). The pressure gauge 111b is an example of a pressure sensor.

  The pressure control circuit 112b inputs an actual pressure value measured by the pressure gauge 111b and a control signal indicating a target decompression value output from a computer (not shown), and calculates a difference value between the input target decompression value and the actual pressure value. A decompression signal (electrical signal) is output. The pressure control circuit 112b is built in, for example, a comparator that outputs a result of comparing two input values.

  The electro-pneumatic proportional control circuit 113b automatically controls the flow rate of air sucked from the compressed air line based on the pressure reduction signal. The electropneumatic proportional control circuit 113b is built in, for example, an electropneumatic regulator that converts an electric signal into an air flow rate.

  The actuator 114b1 opens and closes the valve 114b2 based on the flow rate of air automatically controlled by the electropneumatic proportional control circuit 113b. Specifically, the actuator 114b1 opens the valve 114b2 when air is input, adjusts the opening degree of the valve 114b2 according to the amount of air, and closes the valve 114b2 when no air is input.

  When the solenoid valve 115b is energized in conjunction with the opening / closing timing of the valve 114b2, the solenoid valve 115b is moved to the operating position against the elastic force of the elastic body using the electromagnetic force obtained by the energization. The valve body communicates or blocks the air flow path to the ejector 116b.

  The ejector 116b is connected to the conduit 117b, and blows air from the nozzle toward the atmosphere so that the air between the glass substrate 105 and the transport stage 100 is perforated in the transport stage 100, the conduit 104b, the conduit It sucks through 117b.

  With such a configuration, the air suction 110b controls the flow rate of the air drawn into the conduit 117b, thereby sucking in a desired flow rate of air from the perforation of the transfer stage 100 via the conduit 104b connected to the conduit 117b. It is like that.

  In this way, the air ejection device 110a and the air suction device 110b float the glass substrate 105 by controlling the flow rate of air while monitoring the pressure at the ejection port and the suction port of the transfer stage 100, respectively. Further, the floating position (height) of the glass substrate 105 is controlled by the balance between the amount of air ejected by the air ejecting device 110a and the flow rate of air sucked by the air suction device 110b.

  In the area A1 and the area A2, the levitation transport device 110 is configured by the air ejection device 110a and the air suction device 110b described above. Further, the porous diameter provided in the transfer stage 100 is designed such that the suction side is larger than the blowout side.

(Floating transfer operation under atmospheric pressure)
Next, an operation in which the levitation conveyance device 110 disposed in the area A1 and the area A2 levitates and conveys the glass substrate 105 in the atmosphere will be described with reference to FIG. FIG. 5 shows the transport system 10 of FIG. 2 from the left side with respect to the transport direction.

  As described above, a plurality of air ejection devices 110a (air ejection devices 110a1, air ejection devices 110a2,...) Are installed on the lower left side of the transportation stage 100 with respect to the transportation direction. A plurality of air suction devices 110b (only the air suction device 110b1 is shown) are installed below the right end of the transfer stage 100.

  Note that the air ejection device 110a2 to the air ejection device 110a4 have the same internal configuration as the air ejection device 110a1, and thus are partially omitted. Further, the internal configuration of the air ejection device 110a1 to the air ejection device 110a4 is the same as that of the air ejection device 110a and the air suction device 110b shown in FIG. 4, and the internal configuration of the air suction device 110b1 is shown in FIG. Since it is the same as that of the air suction device 110b, the code | symbol which shows each component is abbreviate | omitted.

  When the glass substrate 105 is levitated and conveyed in the direction of the arrow, the air ejection device 110a1 to the air ejection device 110a4 use the position sensors 103a1 to 103a4 embedded in the conveyance stage 100 at regular intervals. Check each position.

  Thereby, when any one of the air ejection devices 110a confirms that the front side of the glass substrate 105 has been transported, the air ejection device 110a ejects desired air onto the transport stage 100. Thereafter, the air ejection device 110 a continuously increases the flow rate of the ejected air in conjunction with the movement of the glass substrate 105.

  As shown in FIG. 1, each air suction device 110b also confirms the position of the glass substrate 105 using each position sensor 103 embedded in the transfer stage 100 at regular intervals, similarly to the air ejection device 110a. .

  When one of the air suction devices 110b confirms that the front of the glass substrate 105 has been transported, the air suction device 110b sucks the air on the transport stage 100. Thereafter, the air suction device 110b continuously decreases the flow rate of the air to be sucked in conjunction with the movement of the glass substrate 105.

  As a result, the air injected into the lower surface of the glass substrate 105 is controlled such that the pressure on the rear lower surface of the glass substrate 105 is higher than the pressure on the front lower surface of the glass substrate 105 with respect to the transport direction. As a result, the front of the glass substrate 105 is lowered from the rear of the conveyance direction. As a result, the glass substrate 105 is levitated and conveyed in the conveyance direction while being inclined forward.

  That is, when the flow rate of the air ejected by the air ejecting device 110a located rearward with respect to the transport direction is larger than the flow rate of the air ejected by the air ejecting device 110a located in front thereof, the rear lower surface of the glass substrate 105 Is higher than the pressure on the front lower surface of the glass substrate 105.

  Further, when the flow rate of air sucked by the air suction device 110b located rearward with respect to the transport direction is smaller than the flow rate of air sucked by the air suction device 110b located forward of the air suction device 110b, the rear lower surface of the glass substrate 105 Is higher than the pressure on the front lower surface of the glass substrate 105. By such control of the air ejection device 110a and the air suction device 110b, the glass substrate 105 advances while floating.

  Thus, the plurality of air ejection devices 110a and the plurality of air suction devices 110b operate in conjunction with each other according to the position of the glass substrate 105, so that the transport system 10 floats and transports the glass substrate 105 to a predetermined position. Keep doing.

  Further, the pressure (levitation force) between the rear lower surface and the front lower surface of the glass substrate 105 is varied by varying the flow rate of air ejected by each air ejection device 110a and the flow rate of air sucked by each air suction device 110b. be able to. As a result, the transport system 10 can be started and stopped while the glass substrate 105 is floated, and the transport speed can be adjusted according to the inclination angle of the glass substrate 105.

  That is, when the pressure on the rear lower surface of the glass substrate 105 becomes higher than the pressure on the front lower surface of the glass substrate 105 by air control, the glass substrate 105 moves forward while floating. Further, when the pressure on the lower surface of the glass substrate 105 becomes constant, the glass substrate 105 stops. Further, when the pressure on the rear lower surface of the glass substrate 105 becomes lower than the pressure on the front lower surface of the glass substrate 105, the glass substrate 105 moves backward while rising.

  Further, when the difference between the pressure on the front lower surface of the glass substrate 105 and the pressure on the rear lower surface of the glass substrate 105 increases, the conveyance speed of the glass substrate 105 increases, and the pressure on the front lower surface of the glass substrate 105 and the rear of the glass substrate 105 increase. When the difference from the pressure on the lower surface becomes smaller, the conveyance speed of the glass substrate 105 becomes slower.

  By such air control, the glass substrate 105 is levitated and conveyed to the load lock chamber 120, stopped in the load lock chamber 120, and placed on a table provided on the conveyance stage 100.

(Decompression operation)
In this state, the inside of the load lock chamber 120 is depressurized from the atmospheric pressure by roughing the inside of the load lock chamber 120 with a vacuum pump (not shown).

(Floating transfer operation under reduced pressure)
Next, an operation in which the levitation conveyance device 110 disposed in the region B1, the region B2, and the region C causes the glass substrate 105 to float under reduced pressure will be described. As shown in FIG. 6, which is a cross-section of the transport system 10 taken along the 3-3 plane in FIG. 2, the levitation transport device 110 includes an air ejection device 110a, an air suction device 110b, and an air adjustment device 110c. Yes.

  In the load lock chamber 120, the process chamber 130, and the load lock chamber 140, an air adjustment device 110c is required in addition to the air ejection device 110a and the air suction device 110b in order to float and convey the glass substrate 105 under reduced pressure.

  The internal configuration of the air ejection device 110a and the air suction device 110b is the same as that of the air ejection device 110a and the air suction device 110b shown in FIG.

  As described above, the air ejection device 110 a ejects air to the lower surface of the glass substrate 105. The air suction device 110b sucks air on the lower surface of the glass substrate 105. Thereby, the air ejection device 110a and the air suction device 110b adjust the pressure P1 on the lower surface of the glass substrate 105.

  The air adjustment device 110c has the same configuration as the air suction device 110b. Specifically, the pressure gauge 111c, the pressure control circuit 112c, the electropneumatic proportional control circuit 113c, the actuator 114c1, the valve 114c1, the electromagnetic valve 115c, the ejector 116c, and the like It is comprised from the conduit | pipe 117c.

  With such a configuration, the air adjusting device 110c sucks air on the upper surface of the glass substrate 105 in the load lock chamber 120 by a desired flow rate. Thus, the air adjustment device 110c adjusts the pressure P2 on the upper surface of the glass substrate 105. The air adjusting device 110c has the same internal configuration as the air ejecting device 110a, so that a pressure P2 on the upper surface of the glass substrate 105 is ejected by ejecting air at a desired flow rate onto the upper surface of the glass substrate 105 in the load lock chamber 120. May be adjusted.

The relationship between the pressure P1 and the pressure P2 adjusted by the levitation conveyance device 110 in this way is expressed by the following equation (1).
P1 = W _G / A _G × 9.8 × 10 ⁴ + P2 (1)

Here, W _G is the weight (kg) of the glass substrate 105, _AG is the area (cm ² ) of the glass substrate 105, P1 is the pressure (Pa) on the lower surface of the glass substrate 105, and P2 is the pressure (Pa) on the upper surface of the glass substrate 105. ).

For example, the force required to float the 1 (m ² ) glass substrate 105 is 0.11 (g / cm ² ), and the differential pressure is about 10 (Pa). In this way, as a result of controlling the ejection and suction of air so as to satisfy a certain relationship (the relationship of the expression (1)) where the pressure P1> the pressure P2, the glass substrate 105 is under load lock. Ascend inside the chamber 120.

  The method for transporting the glass substrate 105 under reduced pressure is basically the same as the method for transporting the glass substrate 105 under atmospheric pressure. That is, the air ejection device 110a adjusts the flow rate of the air ejected to the front and rear of the glass substrate 105 with respect to the transport method, and the air suction device 110b includes the front and rear of the glass substrate 105 with respect to the transport method. Adjust the flow rate of the air to be sucked into. Thereby, the glass substrate 105 is levitated and conveyed in the conveyance direction while being inclined forward.

  In this way, the glass substrate 105 is levitated and transferred from the load lock chamber 120 to the process chamber 130, subjected to plasma processing in the process chamber 130, and again from the process chamber 130 via the load lock chamber 140, again to a large size. It is levitated and conveyed under atmospheric pressure.

  According to the transport system 10 described above, the glass substrate 105 is levitated and transported not only under atmospheric pressure but also under reduced pressure. Therefore, the glass substrate 105 can be continuously transferred in a non-contact manner in all substrate transfer processes from atmospheric pressure to a reduced pressure state. This eliminates the need to transport the glass substrate 105 by the arm. As a result, it is possible to avoid warping of the glass substrate 105 during conveyance, and to improve the yield of products using the glass substrate 105.

  Further, since no arm is required for transporting the glass substrate 105, the loading / unloading port (frontage) of a container such as a load lock chamber can be made extremely small, for example, about 1/10 of the conventional one. Thereby, a chamber such as a load lock chamber can be made very small. As a result, the exhaust volume is reduced, and the interior of the chamber can be quickly evacuated even by inexpensive equipment such as an ejector. As a result, the tact time can be greatly shortened, and the productivity of the glass substrate 105 can be improved.

For example, the time T until the inside of the chamber reaches a vacuum is expressed by the following equation (2).
T = (L / C) ^{1 / α} (2)
Here, L is the chamber volume, C is a constant according to the degree of vacuum, and α is an index according to the model number of the ejector.

  When each constant is L = 11.25, C = 0.24, α = 1.06, and the load lock chamber 120 is evacuated by eight ejectors, the vacuum reaches in the load lock chamber according to equation (2). The time T is 4.7 (sec). Similarly, the vacuum arrival times T of the process chamber 130 and the load lock chamber 140 are 52 (sec) and 3 (sec), respectively.

  Therefore, if the transport system 10 of this embodiment is used, the tact time can be reduced to a very short time of about 60 (sec).

  Further, according to the transfer system 10, the chamber is downsized (thinned) as described above, and a large exhaust facility is not required. Further, since the glass substrate 105 is continuously conveyed in a non-contact manner, no transfer space is required. As a result, the cost for system construction can be greatly reduced, and the cost for exhaust can be reduced.

  Further, since the transfer system 10 can be applied to an in-line method, the productivity of the glass substrate 105 can be improved by sequentially transferring the glass substrate 105 at a predetermined time interval.

  Further, according to the transport system 10, clean hot dry air is jetted to the lower surface of the glass substrate 105. Thereby, the water | moisture content of the glass substrate 105 vicinity can be removed effectively. In particular, it is very important to remove moisture near the glass substrate for flat panel displays. Therefore, the transport system 10 is particularly effective when transporting a glass substrate for a flat panel display.

  According to the present embodiment, each chamber is exhausted by the ejector disposed in the chamber. For this reason, the ultimate vacuum in the chamber is about 100 (torr). Therefore, when the ultimate vacuum in the chamber is desired to be lower than this, the vacuum may be further reduced using a small auxiliary pump (not shown).

(Configuration and operation of transfer start device and transfer stop device)
Further, when starting the conveyance of the glass substrate 105 and when stopping the conveyance, the conveyance starting device 700a and the conveyance stopping device 700b shown in FIG. 7 may be used. The conveyance starter 700a is used to start conveyance of the glass substrate 105 in a contact manner. The transfer starter 700a includes a pressure gauge 701a, a pressure control circuit 702a, an electropneumatic proportional control circuit 703a, and an air cylinder 704a.

  The pressure gauge 701a measures the pressure in the air cylinder 704a. The pressure control circuit 702a inputs an actual pressure value measured by the pressure gauge 701a and a control signal indicating a target start pressurization value output from a computer (not shown), and a difference between the target start pressurization value and the actual pressure value. A pressurization signal (electric signal) indicating the value is output. The electropneumatic proportional control circuit 703a converts the pressurization signal into an air flow rate. The electropneumatic proportional control circuit 703a is built in, for example, an electropneumatic regulator that converts an electrical signal into an air flow rate.

  When air is input into the air cylinder 704a, the piston inside the cylinder extends to the outside, so that the air cylinder 704a has a rear end portion (conveying direction) of the glass substrate 105 that is levitated by the levitating conveyance device 110 (not shown). On the other hand, the rear portion of the glass substrate 105 is softly pressed. In this way, the conveyance of the glass substrate 105 is started in a contact manner by the conveyance starter 700a.

  Similarly to the transfer starter 700a, the transfer stop device 700b includes a pressure gauge 701b, a pressure control circuit 702b, an electropneumatic proportional control circuit 703b, and an air cylinder 704b. The air cylinder 704b softly receives the front end portion of the glass substrate 105 (the front portion of the glass substrate 105 with respect to the transport direction) by air automatically controlled by the pressure gauge 701b, the pressure control circuit 702b, and the electropneumatic proportional control circuit 703b. . In this way, the conveyance of the glass substrate 105 is stopped in a contact manner by the conveyance stopping device 700b. Note that an exhaust pipe (not shown) is connected to the air cylinder 704a and the air cylinder 704b so as to exhaust the input air.

  According to the conveyance start device 700a and the conveyance stop device 700b described above, the air supplied into the air cylinder is finely controlled by the electropneumatic regulator. Thereby, the conveyance of the glass substrate 105 can be started extremely softly and stopped very softly. As a result, it is possible to prevent generation of dust while the glass substrate 105 is being transported and damage to the glass substrate 105.

(Modification of the first embodiment)
Next, a modification of the first embodiment will be described. This modification is different from the first embodiment in which an electromagnet and a substrate support frame are provided on the transfer stage 100 and the outer peripheral portion of the glass substrate 105 is magnetically levitated under reduced pressure, so that the entire glass substrate 105 is levitated by air. Therefore, this modification will be described below centering on this difference.

(Floating transfer operation under reduced pressure)
As shown in FIG. 8, which is a cross section of the transfer system 10 taken along the 3-3 plane in FIG. 2, the levitating transfer apparatus 110 of this modification is an air ejection apparatus 110a, an air suction apparatus 110b, and an air adjustment apparatus 110c. It is composed of The internal configuration of each device is the same as in the first embodiment, and the reference numerals are omitted.

  On the transfer stage 100 of this modification, a substrate support frame 124 is provided in the vicinity of the outer periphery of the glass substrate 105 at a position where the glass substrate 105 is transferred or stopped. The substrate support frame 124 has a property as a magnetic material. Further, an electromagnet 125 is embedded in the transfer stage 100 below the substrate support frame 124.

  As shown in FIG. 9A in which the portion H of FIG. 8 is enlarged, when the glass substrate 105 is positioned above the substrate support frame 124, a repulsive force is generated between the electromagnet 125 and the substrate support frame 124. A current is passed through the electromagnet 125. As a result, as shown in FIG. 9B, the outer periphery of the glass substrate 105 is magnetically levitated by the repulsive force generated between the electromagnet 125 and the substrate support frame 124. Further, as in the first embodiment, the central portion of the glass substrate 105 floats by adjusting the pressure on the upper and lower surfaces of the glass substrate 105 with air.

  According to the modification described above, the risk of warping of the glass substrate 105 during the conveyance of the glass substrate 105 can be further reduced. In addition, the gap between the substrate support frame 124 and the transfer stage 100 is reduced by the substrate support frame 124 and the electromagnet 125. Thereby, mixing of the air on the lower surface side of the glass substrate 105 and the air on the upper surface side of the glass substrate 105 can be reduced. As a result, the pressure P1 on the lower surface side of the glass substrate 105 and the pressure P2 on the upper surface side of the glass substrate 105 can be adjusted with higher accuracy.

(Second Embodiment)
(Conveyor system configuration and operation)
In the present embodiment, as shown in FIG. 10, a chamber 170 having a plurality of chambers that can be opened and closed by gate valves (gate valve 161, gate valve 162, gate valve 163, gate valve 164. Is different from the first embodiment in which the chambers are arranged in the order of the load lock chamber, the process chamber, and the load lock chamber. Therefore, hereinafter, the transport system 10 according to the second embodiment will be described focusing on this difference.

  When the glass substrate 105 is levitated and conveyed to the front of the gate valve 161 under the control of the levitating conveyance device 110, the gate valve 161 is opened, and the glass substrate 105 is levitated and conveyed into the chamber 170 without stopping. When the entire glass substrate 105 enters the chamber 170, the gate valve 161 is closed.

  Thereafter, when the glass substrate 105 is levitated and conveyed to the front of the gate valve 162, the gate valve 162 is opened. Therefore, the glass substrate 105 is levitated and conveyed in the chamber 170 without stopping, and then the gate valve 162 is closed.

  By repeating such an operation, a plurality of vacuum pumps (not shown) continue to evacuate the chamber 170 while the glass substrate 105 passes through the plurality of chambers in the chamber 170 without stopping. In this way, the glass substrate 105 is continuously levitated and conveyed from the atmospheric pressure to the vacuum pressure. In addition, after passing through the chamber 170, the glass substrate 105 may be levitated into a process chamber (not shown) and subjected to plasma processing.

  According to this embodiment described above, the inside of the container is continuously depressurized without stopping the floating conveyance of the glass substrate 105. Thereby, compared with 1st Embodiment, the inside of a container can be made into a vacuum state rapidly, carrying the floating conveyance of the glass substrate 105. FIG.

  In all the embodiments, substrate conveyance using only air levitation, substrate conveyance using air and magnetic levitation, and substrate conveyance using only magnetic levitation are possible.

  In each of the above embodiments, the operations of the respective units are related to each other, and can be replaced as a series of operations in consideration of the mutual relationship. Therefore, by replacing in this way, the substrate transport system invention can be an embodiment of the substrate transport method invention.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, the glass substrate 105 is transferred in the order of the load lock chamber 120, the process chamber 130, and the load lock chamber 140, and is etched by plasma in the process chamber 130.

  However, the transfer system of the present invention is not limited to a system for performing a plasma treatment on a glass substrate, and can be applied to a system for transferring a substrate in order to apply any processing to the substrate.

  Further, as shown in FIG. 11A, the transfer system of the present invention may be a system in which a load lock chamber, a plurality of process chambers, and a load lock chamber are sequentially connected to the transfer stage 100. Further, a system in which a transfer chamber (transfer module) is connected to these devices may be used. According to this, a plurality of processings can be performed on the glass substrate 105.

  Further, as shown in FIG. 11 (b), the transfer system of the present invention branches one transfer stage 100 into two transfer stages connected in the order of a load lock chamber, a process chamber, and a load lock chamber. Again, the system may be combined with one transfer stage 100. According to this, even when a failure occurs in the apparatus on one of the branched transfer stages 100, the processing can be continued by the process chamber connected to the other transfer stage 100.

  Further, as shown in FIG. 11C, the transfer system of the present invention is configured such that the glass substrate is subjected to plasma processing in an arbitrary process chamber among a plurality of process chambers connected to the load lock chamber on the transfer stage 100. It may be a system constructed as described above. According to this, by selecting an arbitrary chamber for performing a specific processing process from a plurality of process chambers, it is possible to perform various types of processing processes with one transfer system.

  The present invention is applicable to a substrate transfer system that transfers a substrate in a non-contact manner from atmospheric pressure to reduced pressure.

It is the perspective view which showed a part of conveyance system concerning 1st Embodiment of this invention. It is the top view which showed the outline of the conveyance system concerning the embodiment. It is sectional drawing which cut | disconnected the conveyance system of the same embodiment in the 1-1 surface of FIG. It is sectional drawing which cut | disconnected the conveyance system of the same embodiment in 2-2 surface of FIG. It is a left view of the conveyance system concerning the embodiment. It is sectional drawing which cut | disconnected the conveyance system of the embodiment in the 3-3 plane of FIG. It is an internal block diagram of the conveyance start apparatus and conveyance stop apparatus which concern on the embodiment. It is sectional drawing which cut | disconnected the conveyance system concerning the modification of 1st Embodiment in the 3-3 plane of FIG. FIG. 9A is an enlarged view of a portion H in FIG. 8, and FIG. 9B is a diagram for explaining magnetic levitation of the glass substrate. It is sectional drawing which cut | disconnected the conveyance system concerning 2nd Embodiment of this invention. It is the figure which showed the other structural example of the conveyance system concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transfer system 100 Transfer stage 105 Substrate 110 Levitation transfer device 110a Air ejection device 110b Air suction device 110c Air adjustment device 120 Load lock chamber 124 Substrate support frame 125 Electromagnet 130 Process chamber 140 Load lock chamber 170 Chamber 700a Transfer start device 700b Transfer stop apparatus

Claims (6)

A substrate transfer system for transferring a substrate by levitating a substrate under reduced pressure,
A transfer stage provided with a plurality of first and second holes ;
An ejection device that communicates with the first plurality of holes and that ejects gas to the lower surface of the substrate;
An inhaler that communicates with the second plurality of holes and that inhales gas from the lower surface of the substrate;
An adjustment device that adjusts the pressure by blowing gas to the upper surface of the substrate;
Controlling the gas ejected and sucked into the lower surface of the substrate and the gas ejected and sucked into the upper surface of the substrate so that the pressure on the lower surface of the substrate and the pressure on the upper surface of the substrate have a certain relationship A substrate transfer system, wherein the substrate under reduced pressure is levitated.   The levitation transfer device
  The substrate is transported by controlling the gas ejected and sucked into the lower surface of the substrate so that the pressure on the rear lower surface of the substrate is higher than the pressure on the front lower surface of the substrate in the transport direction. The substrate transfer system according to claim 1.   The substrate transfer system according to claim 1, wherein the gas is clean hot dry air.   The substrate transport system according to claim 1, further comprising a substrate support frame that supports the vicinity of the outer periphery of the substrate. The substrate support frame is a magnetic body,
The transfer stage is
An electromagnetic stone in place,
The levitation transfer device
When the substrate support frame is positioned on top of the electromagnet, characterized in that for floating the substrate by the repulsive force between said electromagnet caused by controlling the current supplied to the electromagnet the substrate supporting frame radicals Ita搬 delivery system according to claim 1. A transfer stage provided with first and second holes, an ejection device that communicates with the first holes, and jets gas to the lower surface of the substrate, and communicates with the second holes. , a suction device for sucking gas from the lower surface of the substrate, a group Ita搬 delivery method for conveying while floating the substrate using:
Communicating with the first plurality of holes and ejecting gas to the lower surface of the substrate;
Inhaling gas from the lower surface of the substrate in communication with the second plurality of holes;
Adjusting the pressure by blowing gas onto the upper surface of the substrate,
In each of the steps, a gas jetted and sucked into the lower surface of the substrate and a gas jetted and sucked into the upper surface of the substrate so that the pressure on the lower surface of the substrate and the pressure on the upper surface of the substrate have a fixed relationship group Ita搬 delivery method characterized by floating the said substrate which is under reduced pressure by the control, respectively.

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