JP7744231B2 - Vacuum Processing Equipment - Google Patents

Description

The present invention relates to a vacuum processing apparatus (so-called inline type) that performs a predetermined vacuum processing on the processing surface of a substrate to be processed while transporting a transport tray on one side of which the substrate is placed. More specifically, it relates to an apparatus that can accurately identify the coordinates (absolute position) of the transport tray within a vacuum chamber.

A vacuum processing apparatus of the above type is known, for example, from Patent Document 1. This apparatus comprises multiple vacuum chambers arranged in one direction, and a transport means capable of transporting multiple transport trays in sequence within the vacuum chambers is provided. As the transport trays pass through each vacuum chamber, various vacuum processes such as film deposition, etching, and heat treatment are sequentially performed on the processing surface of the substrate to be processed.

However, there are cases where the vacuum processing in one of the vacuum chambers is halted or interrupted for some reason. Managing production status while anticipating such events requires a configuration that accurately determines the coordinates of each transport tray within the vacuum chamber. In such cases, one option is to equip each transport tray with an encoder, and connect the transport tray's encoder to a control unit (controller) that receives input from this encoder and determines the transport tray's position within the vacuum chamber via a freely movable signal cable. However, some vacuum processing equipment of this type connects adjacent vacuum chambers via gate valves to isolate them from each other, which poses the problem that a method of connecting using a signal cable cannot be applied to these systems.

JP 2010-159167 A

In view of the above, the present invention aims to provide a vacuum processing apparatus that can accurately determine the position of each transport tray in a vacuum chamber, regardless of whether the vacuum chambers are connected via a gate valve.

To solve the above problems, the vacuum processing apparatus of the present invention performs a predetermined vacuum processing on the processing surface of a transport tray on one side of which a substrate is placed while transporting the transport tray. Two mutually perpendicular directions in a horizontal plane are the X-axis direction and the Y-axis direction. The apparatus is provided with a transport means for transporting the transport tray along the X-axis direction within a vacuum chamber. The apparatus has a long scale attached to the transport tray along the X-axis direction and multiple detection units capable of reading the scale's graduations. The detection units are arranged at intervals along the X-axis direction within the vacuum chamber, and the transport tray scale and the detection units directly facing it constitute an absolute encoder. The detection unit located most upstream from where transport of the transport tray begins is used as the starting point detection unit. All detection units other than this starting point detection unit are assigned offset values according to their distance from the starting point detection unit. The apparatus further includes a control unit that, when the graduation of the transport tray is read by any of the detection units, determines the coordinates of the transport tray within the vacuum chamber from the read graduation and offset value.

In the present invention, when multiple transport trays are simultaneously transported into a vacuum chamber, a configuration can be adopted in which each transport tray is assigned a scale value so that they do not overlap with each other, i.e., the minimum and maximum scale values of the scale of each transport tray are set so that they do not overlap with each other. Furthermore, in the present invention, a configuration can be adopted in which the control unit updates the position of the transport tray each time a new scale interval is read by any of the detection units.

As described above, by connecting each detector fixedly installed within the vacuum chamber to the control unit with a signal cable, the absolute position (coordinates) of the transport tray within the vacuum chamber can be accurately determined from the scale interval and offset value read by each detector. This eliminates the need to route signal cables within the vacuum chamber, so determining the coordinates of the transport tray is not hindered even when adjacent vacuum chambers are connected via gate valves. Furthermore, even when multiple transport trays are being transported simultaneously within the vacuum chamber, individual transport trays (types) can be identified using a simple method without the need for additional equipment to identify each tray. Note that when transporting trays within a vacuum chamber, the position of each transport tray is typically determined using a sensor or other device, and the operation of the transport means, such as transport rollers, is controlled accordingly. However, if the detections from each detector constituting the absolute encoder are also used to control the transport unit, the number of parts can be reduced.

In a typical absolute encoder control component (servo amplifier), which consists of a single detector and scale, an alarm (serious failure) is issued based on a detection error if the detector moves outside the scale range. In other words, if the absolute encoder is unable to detect position while a drive unit equipped with an absolute encoder is in operation, the drive unit is typically stopped and an alarm is output to prompt, for example, encoder replacement. In such a case, the alarm can only be cleared (error reset) by cycling power to the control component. For this reason, when attempting to determine the coordinates of transport trays being transported sequentially within a vacuum chamber using a control unit including an existing absolute encoder control component, an alarm is always issued, and power must be cycled to clear the alarm, preventing the transport trays from being transported smoothly.

In this invention, therefore, even if the detection unit that constitutes the absolute encoder and faces the scale of the transport tray moves out of the scale range as the transport tray is transported, it does not issue a detection error, but instead returns a specific value, such as -1, to the control unit, or holds and returns the final value read. If another detection unit reads a new scale interval (in other words, when the other detection unit returns to within the scale range), the coordinates are updated. If the control unit includes control components for an existing absolute encoder, there is no need for the control unit to issue an alarm or reset an error, and there is no impact on identifying the coordinates of the transport tray within the vacuum chamber.

In addition, the control component (servo amplifier) can be configured so that when any of the detection components goes outside the scale range, the alarm is not treated as a serious malfunction, but can be cleared by a signal from the control unit. When another detection component reads the scale interval anew, i.e., when the detection error signal of the detection component drops (turns off), the control unit can clear the alarm of the control component and return to control.

However, if the vacuum process in one of the vacuum chambers is stopped or interrupted for some reason, power may be cut off to the detectors, control unit, and control components that make up the absolute encoder. In this case, the control components of a typical incremental encoder do not retain the coordinates of the transport tray at the time power was cut off. This necessitates some kind of reset operation after power is restored, which can hinder production. In contrast, in this invention, the absolute encoder is made up of the transport tray scale and the detector directly facing it. Therefore, simply by reading the scale graduations again with one of the detectors after power is restored, the control unit can accurately determine the coordinates and type of each transport tray within the vacuum chamber, which is advantageous because it allows reset operations to be performed as quickly as possible.

1 is a vertical cross-sectional view of an in-line vacuum processing apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the in-line vacuum processing apparatus shown in FIG. 1 . FIG. 3 is a cross-sectional view taken along line III-III in FIG. 6A to 6E are diagrams for explaining how to identify the position of each transport tray transported on the first transport path.

With reference to the drawings, an embodiment of the vacuum processing apparatus VM of the present invention will be described below, taking as an example an in-line vacuum processing apparatus capable of performing various vacuum processes, such as film formation, heat treatment, and etching, on one surface (processing surface) of a substrate Sw to be processed, where the substrate is a large-area glass substrate (hereinafter referred to as "substrate Sw") used in the manufacture of flat panel displays. Hereinafter, the direction of movement of the transport tray Tr along the transport paths Tp1 and Tp2 is referred to as the X-axis, the direction of gravitational acceleration perpendicular to the X-axis is referred to as the Z-axis, and the direction perpendicular to the X-axis and Z-axis is referred to as the Y-axis. Furthermore, the position of the transport tray Tr (and substrate Sw) in which one surface (processing surface) of the substrate Sw placed on the transport tray Tr faces in one direction in the Y-axis direction is referred to as an upright position (including a position in which the transport tray Tr is tilted at a predetermined angle with respect to the Z-axis), and the position of the transport tray Tr (and substrate Sw) in which the processing surface of the substrate Sw placed on the transport tray Tr faces upward in the Z-axis direction is referred to as a horizontal position.

Referring to Figures 1 to 3, the inline vacuum processing apparatus VM includes a position chamber Pc in which a transport robot (not shown) places an unprocessed substrate Sw in a horizontal position on one side of a transport tray Tr, or removes a processed substrate Sw from a horizontally positioned transport tray Tr. The transport tray Tr is composed of a plate-like body 11 with an outline slightly larger than the substrate Sw. The plate-like body 11 is provided with a substrate receiving portion 12 against which the bottom edge of the substrate Sw abuts when in an upright position, and a pressing portion (not shown) such as a clamp that locally presses the edge of the substrate Sw against the plate-like body 11, allowing the upright substrate Sw to be held on the transport tray Tr during vacuum processing. Depending on the vacuum processing of the substrate Sw, a mask plate may be attached along with the substrate Sw.

The position chamber Pc, maintained in an atmospheric environment, is equipped with a tilting unit 2 that can tilt while holding the transport tray Tr from the other side, allowing the transport tray Tr to be changed between a horizontal and an upright position. The tilting unit 2 includes a holding plate 21, and a holding mechanism such as a vacuum chuck (not shown) is provided at a predetermined position on the holding plate 21 to prevent the substrate Sw from detaching from the holding plate 21 even when the transport tray Tr is in the upright position. The holding plate 21 is connected to a rotating shaft 23 attached to two frames 22 that are spaced apart in the X-axis direction and can be synchronously extended and retracted up and down in the Z-axis direction by a mechanism such as a single-axis robot (not shown). When the rotating shaft 23 is driven in one direction by a motor Mt, the holding plate 21 rotates around the rotating shaft 23, tilting the transport tray Tr. The lower end of each frame 22 is connected to a single-axis robot movement mechanism 24 installed in the position chamber Pc so that it extends in the Y-axis direction, allowing it to move back and forth freely left and right along the Y-axis.

When a substrate Sw is placed on a horizontally oriented transport tray Tr in the position chamber Pc, the tilting unit 2 rotates the transport tray Tr while lifting it up to place it in an upright position, and then moves it in one direction along the Y axis by the movement mechanism 24 to a position above the transport unit (described below) in the Z axis direction, after which the transport tray Tr is inserted and handed over to the transport unit. On the other hand, when receiving a transport tray Tr containing a processed substrate Sw from the transport unit (described below), the tilting unit 2 holds the transport tray Tr from the other side, then lifts the upright transport tray Tr by pulling it upward in the Z axis direction, then rotates the transport tray Tr while lowering it to place it in a horizontal position, and moves it in the other direction along the Y axis to a predetermined position, allowing the processed substrate Sw to be recovered from the transport tray Tr.

A load lock chamber Lc is connected to the position chamber Pc in the X-axis direction via a gate valve Gv1. Although not specifically shown or described, the load lock chamber Lc is connected to an exhaust pipe from a vacuum pump and a vent gas line for introducing vent gas, allowing the load lock chamber Lc to be switched between a vacuum atmosphere and an air atmosphere as needed. Two processing chambers, for example, Vc1 and Vc2, are connected to the load lock chamber Lc in the X-axis direction via gate valves Gv2 and Gv3, depending on the type of vacuum processing to be performed on the processing surface of the substrate Sw. Each processing chamber Vc1 and Vc2 is separated into two chambers, one on the left and one on the right, in the Y-axis direction by a partition wall 31 extending along the X-axis. Each chamber 31a and 31b is equipped with a device 32 required for performing various vacuum processing, such as a sputtering cathode. The transport tray Tr passes through the chambers 31a and 31b of the processing chambers Vc1 and Vc2 in an upright position with the processing surface of the substrate Sw facing in one direction in the Y-axis direction (downward in Figure 2), and various vacuum processes are performed on the processing surface of the substrate Sw. A turnback chamber Bc is connected to the processing chamber Vc2, which is located at the front and most downstream side in the X-axis direction, via a gate valve Gv4. The position chamber Pc, load lock chamber Lc, processing chambers Vc1 and Vc2, and turnback chamber Bc constitute the vacuum chamber of this embodiment.

Although not specifically shown or described, the turnback chamber Bc is equipped with a movable stage with transport rollers on its upper surface that can move freely in the Y-axis direction (up and down in Figure 2), allowing the transport tray Tr received from the chamber 31a on the left side of the processing chamber Vc2 in the Y-axis direction to be returned to the chamber 31b on the right side of the processing chamber Vc2 in the Y-axis direction. Transport means Tm are also provided to transport the transport tray Tr in an upright position along two transport paths Tp1, Tp2 extending in the X-axis direction between the position chamber Pc and the turnback chamber Bc. In the following, the path that connects the position chamber Pc, which is connected to each other in the X-axis direction, via the load lock chamber Lc and the chamber 31a on the left side of each processing chamber Vc1, Vc2 in the Y-axis direction, to the turnback chamber Bc, and through which the transport tray Tr is transported forward in the X-axis direction (from left to right in Figures 1 and 2), is referred to as the outgoing transport path Tp1. Conversely, the path that connects the turnback chamber Tc to the chamber 31b on the right side of the Y-axis direction, via the load lock chamber Lc, and through which the transport tray Tr is transported backward in the X-axis direction (from right to left in Figure 1), ... is referred to as the return transport path Tp2.

The transport means Tm includes a first guide unit 4 that guides the upright transport tray Tr in its forward or backward movement in the X-axis direction while pulling it upward in the Z-axis direction without contact; a transport unit 5 that contact-supports the remaining weight of the transport tray Tr, part of whose weight has been pulled by the first guide unit 4, and transports the transport tray Tr in its forward or backward movement in the X-axis direction; and a second guide unit 6 that guides the transport tray Tr in its forward or backward movement in the X-axis direction while pulling it upward in the Z-axis direction without contact below the Z-axis. The first guide unit 4 includes a first magnet 41 that is elongated in the X-axis direction and attached along the upper edge of the Z-axis upper surface of the plate-like body 11 of the transport tray Tr; and second magnets 42 that are arranged along the forward transport path Tp1 and the return transport path Tp2, respectively, at the upper Z-axis positions within the position chamber Pc, the load lock chamber Lc, and each of the processing chambers Vc1 and Vc2. The first magnets 41 and second magnets 42 are magnetized so that the polarities of their opposing surfaces are different, thereby guiding the movement of the transport tray Tr back and forth in the X-axis direction while pulling it upward in the Z-axis direction without contact. The first magnets 41 and second magnets 42 can also be arranged in multiple rows spaced apart in the Y-axis direction, in which case it is preferable to alternate the polarities of the first magnets 41 and second magnets 42 facing each other.

The transport unit 5 includes a plurality of transport rollers 51 serving as rolling elements, spaced apart in the X-axis direction at the bottom of the position chamber Pc, load lock chamber Lc, and each of the processing chambers Vc1 and Vc2 along the forward transport path Tp1 and the return transport path Tp2. Each transport roller 51 is composed of a shaft 51a journaled at a predetermined position within the position chamber Pc, load lock chamber Lc, and each of the processing chambers Vc1 and Vc2, and a wheel 51b fitted onto each shaft 51a and in contact with the underside of the transport tray Tr in the Z-axis direction. In this case, at least two wheel 51b are attached to a single shaft 51a at intervals in the Y-axis direction, and the tips of the wheel 51b are elliptical and tapered radially outward, allowing the wheel 51b to make point contact with the underside of the transport tray Tr in the Z-axis direction. Although not specifically shown or described, the shaft 51a of each conveying roller 51 is connected to a known power transmission mechanism such as a pulley, gear, drive belt, or motor, and each conveying roller 51 is driven to rotate in the same direction in synchronization for the forward conveying path Tp1 and the return conveying path Tp2.

The second guide section 6 includes a third magnet (one of the magnets) 61 provided at the bottom of the transport tray Tr in the Z-axis direction, and a fourth magnet 62 arranged at the bottom of the position chamber Pc, the load lock chamber Lc, and each of the processing chambers Vc1 and Vc2 along the forward transport path Tp1 and the return transport path Tp2. A support plate section 13 is formed on the plate-like body 11 of the transport tray Tr, extending outward from its lower end on the other side (left side in Figure 3) opposite the one side on which the substrate Sw is placed, and the third magnet 61 is provided on the upper surface of the support plate section 13 in the Z-axis direction. Meanwhile, along the forward transport path Tp1 and the return transport path Tp2, in the lower Z-axis direction within the position chamber Pc, the load lock chamber Lc, and each of the processing chambers Vc1 and Vc2, a support wall 63 having a horizontal wall portion 63a facing the support plate portion 13 of the transport tray Tr at a distance in the Z-axis direction is provided so as to extend along the X-axis direction, and a fourth magnet 62 is provided on the underside of the horizontal wall portion 63a. The third magnet 61 and the fourth magnet 62 are magnetized so that the polarities of their opposing surfaces are different, thereby guiding the movement of the transport tray Tr back and forth in the X-axis direction while pulling the lower Z-axis direction of the transport tray Tr upward in the Z-axis direction without contact. Note that the third magnets 61 and the fourth magnets 62 can also be provided in multiple rows spaced apart in the Y-axis direction, as described above. In this case, it is preferable to alternate the polarities of the third magnets 61 and the fourth magnets 62 facing each other. The transport means Tm is also equipped with an absolute encoder so that the position of each transport tray Tr present in the position chamber Pc, load lock chamber Lc, processing chambers Vc1 and Vc2, and turnback chamber Bc can be determined.

Referring also to Figure 4, a long scale (code plate) 71 is attached to the bottom of each transport tray Tr along its entire length in the X-axis direction. Furthermore, multiple detectors 72a-72o are arranged at predetermined intervals along the X-axis direction on the support walls 63 elongated in the X-axis direction provided in the position chamber Pc, load lock chamber Lc, processing chambers Vc1 and Vc2, and turnback chamber Bc. The scale 71 of each transport tray Tr and the detectors 72a-72o form an absolute encoder. For ease of explanation, the most upstream detector located at the transfer position of the outgoing transport path Tp1 in the position chamber Pc (i.e., where the transport of the upright transport tray Tr begins) is referred to as the starting point detector 72a below. Determining the coordinates of a transport tray Tr will be described using the example of transporting a transport tray Tr from the transfer position of the outgoing transport path Tp1 toward the turnback chamber Bc.

Each of the detectors 72a-72o may be of a known type, such as an optical or magnetic type, and the scale 71 attached to each transport tray Tr may be of a known type that corresponds to the type of detector 72a-72o. For example, if optical detectors 72a-72o are used, the scale 71 may have multiple layers with different reflectivities patterned on its surface (hereinafter, as shown in Figure 4, the scale 71 has a scale length (obtained by subtracting the minimum scale value from the maximum scale value) of 999 mm, with a scale interval of 1 mm, but the scale interval can be set appropriately depending on the required accuracy). In this case, for example, the scale values on the scale 71 for each of the transport trays Tr1, Tr2, and Tr3 are set so that they do not overlap with each other, such as 0 to 999 mm for the first transport tray (this will be referred to as the "first transport tray Tr1"), 1000 mm to 1999 mm for the next transport tray (this will be referred to as the "second transport tray Tr2"), and 2000 mm to 2999 mm for the next transport tray (this will be referred to as the "third transport tray Tr3").

The spacing between adjacent detectors 72a-72o on the outbound transport path Tp1 and the return transport path Tp2 is set to be smaller (e.g., 800 mm) than the length of the scale 71 graduations (0-999 mm). Each detector 72a-72o is connected to a control unit Cu installed in the atmosphere via a signal cable Sk, and the scale 71 graduations read by each detector 72a-72o are output to the control unit Cu. The absolute encoder 7 itself is a publicly known device, except for when the combination of the scale 71 and detector 72 is changed or when the detector 72 is not directly facing the scale 71. Therefore, further detailed explanations, including the scale format, the method of outputting the read graduations (encoder values) to the control unit Cu (output as a digital signal or analog signal), and the method of calculating coordinates on the outbound transport path Tp1 from the read graduations, are omitted.

The control unit Cu is a well-known device that includes a microcomputer, sequencer, memory, etc., and controls the overall operation of the vacuum pump, transport means Tm, and other operating parts installed in the vacuum processing device VM. The control unit Cu also controls the operation of each of the detection units 72a-72o (i.e., the control unit Cu includes control components (e.g., servo amplifiers) similar to a general absolute encoder (not shown)), and receives output from each of the detection units 72a-72o to determine the coordinates of each transport tray Tr on the forward transport path Tp1 and return transport path Tp2. The determined positions can then be output to external devices such as displays or to a higher-level overall control device that controls the production line including the vacuum processing device VM.

Specifically, as shown in FIG. 4, assuming that the detection units 72a-72o are arranged at equal intervals of, for example, 800 mm, when the first transport tray Tr1 is transported along the outbound transport path Tp1, the start point detection unit 72a first faces the scale 71 of the first transport tray Tr1 and reads the start point (e.g., the minimum scale value 0) of the scale 71 of the first transport tray Tr1. As the first transport tray Tr1 continues to be transported, the scale interval (e.g., 200) read by the start point detection unit 72a is output to the control unit Cu. At this time, the control unit Cu determines the coordinates of the first transport tray Tr1 on the outbound transport path Tp1 from the read scale interval (200) (see FIG. 4(a)). In this case, the control unit Cu stores the coordinates of the first transport tray Tr determined based on the scale interval of the scale 71 read by the starting point detection unit 72a, and updates the coordinates of the first transport tray Tr each time a new scale interval is read by the starting point detection unit 72a.

As the first transport tray Tr1 continues to be transported along the outbound transport path Tp1, the start point detection unit 72a and the adjacent next detection unit 72b each face the scale 71 of the first transport tray Tr1, and the start point (minimum scale value 0) of the scale 71 of the first transport tray Tr1 is read by the next detection unit 72b. At this time, the start point detection unit 72a also reads the scale 71's graduation (800), but the control unit Cu identifies and retains the coordinates of the transport tray Tr1 based on the graduation of the scale 71 read by the detection unit 72b. The control unit Cu also stores an offset value (800) corresponding to the distance between the starting point detection unit 72a and the detection unit 72b. When the starting point (minimum scale value 0) of the first transport tray Tr1 is read by the detection unit 72b, the control unit Cu determines the coordinates of the first transport tray Tr1 on the outbound transport path Tr1 from the read scale interval (0) of the scale 71 and the offset value (800) (see FIG. 4(b)). In this way, an offset value (the distance between the detection units 72 (an integer multiple of 800)) corresponding to the distance from the starting point detection unit 72a is assigned to each of the detection units 72 other than the starting point detection unit 72a and stored in the control unit Cu.

As the first transport tray Tr1 continues to travel along the transport path Tp1, the control unit Cu determines the coordinates of the first transport tray Tr1 based on the scale interval (e.g., 500) and offset value (800) of the scale 71 read by the detection unit 72b (see Figure 4(c)). If the first transport tray Tr1 continues to travel, the starting point detection unit 72a will move out of the scale range of the transport tray Tr (the scale 71 and the detection unit 72 will no longer be directly facing each other). However, the control components of the absolute encoder 7 do not issue a detection error but instead return a specific value of -1 to the control unit Cu. Because the detection unit 72b has read the scale interval of the scale 71, there is no need for the control unit Cu to issue an alarm or reset the error to the control components of the absolute encoder 7. This does not affect the determination of the absolute positions (coordinates) of the transport trays Tr1 to Tr3 on the outbound transport path Tp1. Thereafter, while repeating the above operation, the control unit Cu reads the scale interval of the first transport tray Tr1 using each of the detection units 72c, 72d, 72e, 72f, 72g, and 72h, and determines the coordinates of the transport tray Tr1 on the outgoing transport path Tp1 from the read scale interval and offset value of the scale 71 (see Figure 4(d), coordinates of the first transport tray Tr1).

In addition to the above, when the second transport tray Tr2 is transported along the outbound transport path Tp1 in addition to the first transport tray Tr1, the start point detector 72a reads the start point (minimum scale value 1000) of the second transport tray Tr2. Then, when the second transport tray Tr2 is further transported, the scale interval (e.g., 1200) of the scale 71 read by the start point detector 72a is output to the control unit Cu, and the coordinates of the second transport tray Tr2 along the outbound transport path Tp1 are determined. Note that, when determining the coordinates, a process of subtracting the minimum scale value is required. In this embodiment, since the minimum scale value increases in units of 1000, for example, the read scale interval can be divided by 1000, the quotient can be used to identify each transport tray Tr1-Tr3, and the remainder can be used to determine the coordinates. In this case, it is preferable for the minimum scale value of the scale 71 attached to each transport tray Tr1-Tr3 to be an integer multiple, from a computational perspective.

Here, the scale values of 1000 (minimum scale value) to 1999 (maximum scale value) on the scale 71 are assigned to the second transport tray Tr2. Therefore, for example, when the starting point detector 72a reads the starting point of the second transport tray Tr2, the transport tray is identified as the second transport tray Tr2. Then, when the second transport tray Tr2 is further transported, the scale interval (e.g., 1200) of the scale 71 read by the starting point detector 72a allows the control unit Cu to determine that the second transport tray Tr2 is currently at coordinate 200 on the outgoing transport path Tp1 (see FIG. 4(d) for the coordinates of the second transport tray Tr2). Furthermore, when the third transport tray Tr3 is transported, the scale interval (e.g., 2200) read by the starting point detector 72a is similarly output to the control unit Cu, and the coordinates and type of the third transport tray Tr3 on the outgoing transport path Tp1 are identified (see FIG. 4(e)). In this way, by ensuring that the scale values on the scale 71 for each transport tray Tr1-Tr3 do not overlap, the control unit Cu can determine the type of each transport tray Tr1-Tr3 from the scale intervals read by each detection unit 72. Thereafter, by repeating the above operation, the control unit Cu can identify each transport tray Tr (Tr1-Tr3) being transported on the outgoing transport path Tp1 and the returning transport path Tp2, and determine the coordinates of each transport tray Tr on the outgoing transport path Tp1 and the returning transport path Tp2.

In the above embodiment, by connecting the detection units 72a-72o fixedly arranged in the position chamber Pc, load lock chamber Lc, processing chambers Vc1 and Vc2, and turnback chamber Bc to the control unit Cu via signal cables Sk, the absolute position (coordinates) of the transport tray Tr on the forward transport path Tp1 or the return transport path Tp2 can be determined from the scale intervals and offset values read by each detection unit 72. This eliminates the need to route signal cables within each chamber Pc, Lc, Vc1, Vc2, and Bc, so determining the absolute position of the transport tray Tr is not hindered even when adjacent chambers are connected via gate valves Gv1-Gv4. Furthermore, by having the control unit Cu perform feedback control of the operation of the transport unit 5, i.e., the transport of the transport tray Tr, based on the scale intervals read by each detection unit 72, the number of parts can be reduced, which is advantageous.

Furthermore, if the vacuum processing in one of the vacuum chambers is stopped or interrupted for some reason, causing power supply to the detectors 72a-72o, control unit Cu, and control components to be cut off, simply by reading the scale 71 again using one of the detectors 72a-72o after power supply is restored (power restored), the control unit Cu can accurately determine the coordinates and type of each transport tray Tr1-Tr3, advantageously allowing for a return operation to be performed as quickly as possible. In other words, in this embodiment, by dividing the scale interval obtained from each detector 72 after power supply is restored by 1,000, which is an integer multiple of the minimum scale value, the identification and position of each transport tray Tr1-Tr3 can be immediately obtained without performing a return-to-origin operation, resulting in a vacuum processing apparatus VM that is advantageous in terms of production efficiency. This can be said to be a transport tray identification and absolute position detection system that takes advantage of the changeable combination of scale 71 and detection unit 72 to instantly determine the identification and absolute position of each transport tray Tr1 to Tr3.

The above describes an embodiment of the present invention, but various modifications are possible without departing from the scope of the technical concept of the present invention. In the above embodiment, the transport unit 5 includes transport rollers 51 that support the transport tray Tr by making point contact with the underside of the Z-axis direction. However, this is not limited to this, and other known types, such as spherical or magnetically levitated types, can also be used. In addition, while the above embodiment provides two wheel units 51b, a single wheel unit can also be used. Furthermore, the tip of the wheel unit 51b is configured to make point contact with the underside of the transport tray Tr in the Z-axis direction, and this point contact portion is configured to transmit rotational driving force via the shaft 51a. However, if a constant velocity joint, for example, is used at the fitting portion between the wheel unit 51b and the shaft 51a, driving force can be reliably transmitted to the transport tray Tr by rolling contact.

In the above embodiment, the first guide unit 4 and the second guide unit 6 are described as having a pair of magnets 41, 42, 61, 62 arranged to attract each other. However, the first guide unit 4 is not limited to this, as long as it can pull most of the weight of the transport tray Tr (including the weight of the substrate Sw) and can limit to some extent the degrees of freedom in at least the X-axis direction, the Z-axis direction up and down movement, and the Y-axis direction left and right rotation (pitching). Although not specifically illustrated or described, for example, rail members may be provided at the top of the position chamber Pc, load lock chamber Lc, and each processing chamber Vc1, Vc2, sliders may be provided that slidably engage with these rail members, and the transport tray Tr may be pulled and guided by multiple wires suspended from the sliders at intervals in the X-axis direction. On the other hand, the second guide section 6 is also not limited to this, and may have a configuration similar to that of the first guide section, as long as it can limit to some extent the degree of freedom of rotation (roll) of the transport tray Tr around the front-to-back axis in the X-axis direction and left-to-right movement in the Y-axis direction. Also, while the above embodiment has been described using an example in which the transport tray Tr is transported in an upright position, the present invention is not limited to this, and can be applied regardless of the position of the transport tray Tr during transport.

VM...vacuum processing device, Sw...substrate (substrate to be processed), Tr, Tr1-Tr3...transport tray, Tm...transport means, 71...scale, 72a-72o...detection unit, 72a...starting point detection unit, Cu...control unit, Pc...position chamber (vacuum chamber), Lc...load lock chamber (vacuum chamber), Vc1, Vc2...processing chamber (vacuum chamber), Bc...turnback chamber (vacuum chamber).

Claims (2)

A vacuum processing apparatus that performs a predetermined vacuum processing on a processing surface of a substrate to be processed while transporting a transport tray on one surface of which the substrate to be processed is placed,
Two directions orthogonal to each other in a horizontal plane are defined as an X-axis direction and a Y-axis direction, and a conveying means is provided for conveying a conveying tray along the X-axis direction within a vacuum chamber,
an absolute encoder comprising a long scale attached to the carrier tray along the X-axis direction and a plurality of detectors capable of reading the scale graduations, the detectors being arranged at intervals along the X-axis direction within a vacuum chamber, and the scale on the carrier tray and the detectors directly facing it;
a control unit that determines the coordinates of the transport tray in the vacuum chamber from the scale interval and the offset value when the scale interval and the offset value are read by any of the detection units, and that sets an offset value according to the distance from the origin detection unit to each of the detection units other than the origin detection unit as a start point detection unit ;
A vacuum processing apparatus characterized in that, when multiple transport trays are transported simultaneously into a vacuum chamber, each transport tray is assigned a scale value on the scale so that they do not overlap with each other, the minimum scale value of the scale attached to each transport tray is an integer multiple, the scale interval read by the detection unit is divided by the integer multiple increase in the minimum scale value, the quotient is used to identify each transport tray, and the remainder is used to specify the coordinates . 2. The vacuum processing apparatus according to claim 1 , wherein the control unit is configured to update the coordinates of the transport tray from the scale interval at that time each time a new scale interval is read by any of the detection units.