Vacuum Processing Equipment

Abstract

To enable a position of each conveyance tray existing in a vacuum chamber to be accurately recognized irrespective of whether or not each vacuum chamber is in a state of connected row arrangement through a gate valve when vacuum processing is performed while conveying a conveyance tray in which a processed substrate is arranged.SOLUTION: A vacuum processing apparatus comprises: a long scale 71 that is attached to a conveyance tray; and a plurality of detection units 72a-72o that can read a scale interval of the scale, and each detection unit is arranged having an interval along an x-axis direction within a vacuum chamber, to constitute an absolute encoder using the scale of the conveyance tray and a detection unit confronting the scale. A detection unit that is positioned at a most upstream side where conveyance of the conveyance tray is started is denoted as an original point detection unit, an offset value depending on a distance from the original point detection unit is given to other detection unit except for the original point detection unit, and when a scale interval of the conveyance tray is read using the detection unit by a control unit, a coordinate of the conveyance tray within the vacuum chamber is identified from the read scale interval and the offset value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a (so-called inline) vacuum processing apparatus 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, and more specifically, to an apparatus that enables the coordinates (absolute position) of the transport tray within a vacuum chamber to be accurately determined. [Background technology]

[0002] A vacuum processing apparatus of the above type is known, for example, from Patent Document 1. This apparatus includes a plurality of vacuum chambers arranged in one direction, and a transport means capable of sequentially transporting a plurality of transport trays is provided within the vacuum chambers. As the transport tray passes through each vacuum chamber, various vacuum processes such as film formation, etching, and heat treatment are sequentially performed on the processing surface of the substrate to be processed.

[0003] Here, there may be cases where the vacuum processing in one of the vacuum chambers is stopped or interrupted for some reason. To manage the production status while anticipating such a situation, it is necessary to configure the system so that the coordinates of each transport tray within the vacuum chamber can be accurately determined. In such a case, it is conceivable to mount an encoder on each transport tray and connect the encoder to a control unit (controller) that receives input from the encoder and determines the position of the transport tray within the vacuum chamber via a wired signal cable. However, among these types of vacuum processing equipment, there are some that connect adjacent vacuum chambers via gate valves so that they can be isolated from each other, which makes it difficult to use a signal cable for connection. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-159167 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above, an object of the present invention is to provide a vacuum processing apparatus that can accurately grasp the position of each transport tray present in a vacuum chamber, regardless of whether the vacuum chambers are connected via a gate valve. [Means for solving the problem]

[0006] In order 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 transport tray having a substrate to be processed placed thereon is transported. Two mutually perpendicular directions in a horizontal plane are defined as X-axis and Y-axis directions, and a transport means is provided for transporting the transport tray along the X-axis direction within a vacuum chamber. The vacuum processing apparatus has a long scale attached to the transport tray along the X-axis direction and a plurality of detection units capable of reading the graduations of this scale, and the detection units are arranged at intervals along the X-axis direction within the vacuum chamber, so that the scale on the transport tray 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 a starting point detection unit, and the other detection units except for this starting point detection unit are each assigned an offset value according to the distance from the starting point detection unit, and further comprises a control unit that, when the graduation of the transport tray is read by any of the detection units, identifies the coordinates of the transport tray within the vacuum chamber from the read graduation and the offset value.

[0007] In the present invention, when a plurality of transport trays are simultaneously transported into the vacuum chamber, the transport trays may be provided with scale values ​​so that they do not overlap with each other, i.e., the minimum and maximum scale values ​​of the scale of each transport tray may be set so that they do not overlap with each other. Also, in the present invention, the control unit may be configured to update the position of the transport tray every time a new scale interval is read by any of the detection units.

[0008] According to the above, by connecting each detector fixedly disposed within the vacuum chamber to the control unit via 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. Since there is no need to route a signal cable within the vacuum chamber, determining the coordinates of the transport tray is not hindered even when adjacent vacuum chambers are connected via a gate valve. Furthermore, even when multiple transport trays are transported simultaneously within the vacuum chamber, individual transport trays (types) can be identified using a simple method without the need for additional equipment for identifying each transport tray. When transporting transport trays within a vacuum chamber, the positions of the transport trays are typically determined using sensors or the like, and the operation of the transport units of the transport means, such as transport rollers, is controlled accordingly. However, if the detections of each detector constituting the absolute encoder are also used to control the transport units, the number of parts can be reduced.

[0009] Here, the control components (servo amplifiers) of a typical absolute encoder, which are composed of a single detector and scale, issue an alarm (serious failure) based on a detection error when the detector moves outside the scale range. In other words, if the absolute encoder becomes unable to detect position while a drive device equipped with an absolute encoder is in operation, the drive device is typically stopped and an alarm is output to prompt, for example, encoder replacement. In such cases, the alarm can only be cleared (error reset) by re-applying power to the control component. For this reason, when an attempt is made to identify 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 the power must be re-applied to clear the alarm, preventing smooth transport of the transport trays.

[0010] Therefore, in the present invention, 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, for example -1, to the control unit, or holds and returns the final value that it read.If a new scale interval is read by another detection unit (in other words, when the other detection unit returns to the scale range), the coordinates are updated.If the control unit includes control components for an existing absolute encoder, it is no longer necessary for the control unit to issue an alarm or reset an error to the control components, and therefore there is no impact on the identification of the coordinates of the transport tray within the vacuum chamber.

[0011] Furthermore, the control component (servo amplifier) ​​may be configured so that the alarm generated when any of the detection components goes outside the scale range is not treated as a serious malfunction, but can be cleared by a signal from the control unit, and 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 clears the alarm of the control component and returns to control.

[0012] 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 of power cutoff. This necessitates some kind of reset operation after power is restored (power is restored), which can hinder production. In contrast, in the present invention, the absolute encoder is configured with the transport tray scale and the detector directly facing it. Therefore, after power is restored (power is restored), the control unit can accurately determine the coordinates and type of each transport tray in the vacuum chamber simply by reading the scale graduations again with one of the detectors. This advantageously allows the reset operation to be performed as quickly as possible. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a vertical cross-sectional view of an in-line vacuum processing apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the in-line vacuum processing apparatus shown in FIG. 1. [Figure 3] Cross-sectional view along line III-III in Figure 1. [Figure 4] 10(a) to 10(e) are diagrams for explaining how to identify the position of each transport tray transported on the first transport path. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, with reference to the drawings, an embodiment of the vacuum processing apparatus VM of the present invention will be described, 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 large-area glass substrate (hereinafter referred to as "substrate Sw") used in the manufacture of flat panel displays as a substrate to be processed. In the following, the direction of movement of the transport tray Tr along the transport paths Tp1 and Tp2 is defined as the X-axis direction, the direction of gravitational acceleration perpendicular to the X-axis direction as the Z-axis direction, and the direction perpendicular to the X-axis and Z-axis directions as the Y-axis direction. Furthermore, the position of the transport tray Tr (and the substrate Sw) in which one surface (processing surface) of the substrate Sw placed on the transport tray Tr faces one side in the Y-axis direction is defined 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 the 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 defined as a horizontal position.

[0015] 1 to 3, an inline vacuum processing apparatus VM includes a position chamber Pc in which a transfer robot (not shown) places an unprocessed substrate Sw in a horizontal position on one side of a transfer tray Tr, or removes a processed substrate Sw from a horizontally positioned transfer tray Tr. The transfer tray Tr is composed of a plate-like body 11 having an outline slightly larger than that of the substrate Sw. The plate-like body 11 is provided with a substrate receiving portion 12 against which the lower edge of the substrate Sw abuts when the substrate Sw is 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, so that the upright substrate Sw can be held on the transfer tray Tr during vacuum processing. Depending on the vacuum processing to be performed on the substrate Sw, a mask plate may be attached together with the substrate Sw.

[0016] 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. 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 moving mechanism 24 of a single-axis robot provided in the position chamber Pc so as to extend in the Y-axis direction, allowing for reciprocating movement left and right along the Y-axis direction.

[0017] When a substrate Sw is placed on a transport tray Tr in a horizontal position in the position chamber Pc, the tilting unit 2 rotates the transport tray Tr while lifting it up to put it in an upright position, and then moves it in one direction in the Y-axis direction to a position above the transport unit (described later) in the Z-axis direction by the moving mechanism 24, and then hands over the transport tray Tr to the transport unit by inserting it. On the other hand, when receiving a transport tray Tr containing a processed substrate Sw from the transport unit (described later), the tilting unit 2 holds the transport tray Tr from the other side, then lifts the transport tray Tr in the upright position by pulling it out upward in the Z-axis direction, and then rotates the transport tray Tr while holding it down to change it to a horizontal position, and moves it in the other direction in the Y-axis direction to a predetermined position, making it possible to recover the processed substrate Sw from the transport tray Tr.

[0018] 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 Vc1 and Vc2, for example, 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 left and right chambers in the Y-axis direction by a partition wall 31 extending along the X-axis direction. 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 one side in the Y-axis direction (downward in FIG. 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.

[0019] Although not specifically shown or described, the turnback chamber Bc is provided with a moving stage with transport rollers on its upper surface that is movable in the Y-axis direction (vertical direction in FIG. 2), and the transport tray Tr received from the chamber 31a on the left side of the processing chamber Vc2 in the Y-axis direction can be returned to the chamber 31b on the right side of the processing chamber Vc2 in the Y-axis direction. Transport means Tm are provided so that the transport tray Tr can be transported 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, through 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 forward transport path Tp1. Conversely, the path that connects the turnback chamber Tc through the chamber 31b on the right side of the Y-axis direction, through 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.

[0020] The transport means Tm includes a first guide unit 4 that guides the transport tray Tr in an upright position to move forward or backward in the X axis direction while pulling it upward in the Z axis direction without contact, a transport unit 5 that contacts and supports the remaining weight of the transport tray Tr after part of its weight has been pulled by the first guide unit 4 and transports the transport tray Tr forward or backward in the X axis direction, and a second guide unit 6 that guides the transport tray Tr in a forward or backward direction while pulling it upward in the Z axis direction without contact at a lower part of the Z axis direction of the transport tray Tr. The first guide unit 4 includes a first magnet 41 that is elongated in the X axis direction and is attached along the upper edge of the plate-like body 11 of the transport tray Tr on the upper surface of the Z axis direction of the plate-like body 11, and second magnets 42 that are arranged along the forward transport path Tp1 and the return transport path Tp2, respectively, at the upper part of the Z axis direction in the position chamber Pc, the load lock chamber Lc, and each of the processing chambers Vc1 and Vc2. The first magnet 41 and the second magnet 42 are magnetized so that the polarities of their opposing surfaces are different, thereby respectively guiding 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 the second magnets 42 can also be provided 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 the second magnets 42 that face each other.

[0021] The transport unit 5 includes a plurality of transport rollers 51 serving as rolling elements, which are provided at intervals in the X-axis direction 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. Each transport roller 51 is composed of a shaft 51a journaled at a predetermined position in the position chamber Pc, the 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, so that the wheel 51b makes 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 each of the forward conveying path Tp1 and the return conveying path Tp2.

[0022] 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, Vc2 along the outgoing 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 the lower end on the other surface side (left side in FIG. 3) facing away from the one surface on which the substrates Sw are 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 position chamber Pc, the load lock chamber Lc, and each of the processing chambers Vc1 and Vc2, at the lower part in the Z-axis direction, 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, 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 part of the 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 also includes an absolute encoder so that the position of each transport tray Tr present in the position chamber Pc, the load lock chamber Lc, the processing chambers Vc1 and Vc2, and the turnback chamber Bc can be grasped.

[0023] Referring also to FIG. 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, a plurality of detectors 72a-72o are arranged at predetermined intervals along the X-axis direction on support walls 63 elongated in the X-axis direction provided in each of 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 starts) is referred to as the starting point detector 72a below. The determination of the coordinates of the transport tray Tr will be described using an example in which the transport tray Tr is transported from the transfer position of the outgoing transport path Tp1 toward the turnback chamber Bc.

[0024] Each of the detectors 72a to 72o can be of a known type, such as an optical type or a magnetic type, and a known type corresponding to the type of each of the detectors 72a to 72o is used as the scale 71 attached to each of the transport trays Tr. For example, when optical detectors 72a to 72o are used, the scale 71 has, for example, a plurality of layers with different reflectances patterned on its surface (hereinafter, as shown in FIG. 4, the length of the scale 71 (obtained by subtracting the minimum scale value from the maximum scale value) is set to 999 mm, and the intervals are set at 1 mm intervals, but the intervals can be set appropriately depending on the accuracy). In this case, for example, the scale values ​​of the scale 71 for each of the transport trays Tr1, Tr2, and Tr3 are set so that they do not overlap with each other, i.e., the minimum and maximum scale values ​​of 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 transport tray after that (this will be referred to as the "third transport tray Tr3").

[0025] The intervals between adjacent detectors 72a-72o on the forward conveyance path Tp1 and the return conveyance path Tp2 are set to be smaller (e.g., 800 mm) than the length of the graduations on the scale 71 (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 graduations of the scale 71 read by each detector 72a-72o are output to the control unit Cu. The absolute encoder 7 itself is a known one, 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 form of the graduations, 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 the coordinates on the forward conveyance path Tp1 from the read graduations, are omitted.

[0026] The control unit Cu is a known device having a microcomputer, a sequencer, a memory, etc., and controls the overall operation of the operating parts provided in the vacuum processing device VM, such as the vacuum pump, the transport means Tm, etc. The control unit Cu also controls the operation of each of the detection units 72a-72o (i.e., the control unit Cu includes control parts (e.g., servo amplifiers) similar to a general absolute encoder (not shown)), receives outputs from each of the detection units 72a-72o, identifies the coordinates of each of the transport trays Tr on the outgoing transport path Tp1 and the return transport path Tp2, and then outputs the identified positions to an external device such as a display, or to a higher-level overall control device that controls a production line including the vacuum processing device VM.

[0027] Specifically, as shown in Fig. 4, assuming that the detectors 72a to 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 detector 72a first faces the scale 71 of the first transport tray Tr1, and reads the start point (for example, the minimum scale value 0) of the scale 71 of the first transport tray Tr1. When the first transport tray Tr1 is further transported, the scale interval (for example, 200) read by the start point detector 72a is output to the control unit Cu. At this time, the control unit Cu identifies 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 graduation 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 graduation is read by the starting point detection unit 72a.

[0028] When the first transport tray Tr1 is further transported along the outbound transport path Tp1, in addition to the starting point detection unit 72a, the next adjacent detection unit 72b also faces the scale 71 of the first transport tray Tr1, and the next detection unit 72b reads the starting point (minimum scale value 0) of the scale 71 of the first transport tray Tr1. At this time, the starting point detection unit 72a also reads the graduation (800) of the scale 71, but the control unit Cu identifies and stores the coordinates of the transport tray Tr1 based on the graduation of the scale 71 read by the detection unit 72b. Furthermore, the control unit Cu stores an offset value (800) according to the distance between the starting point detector 72a and the detector 72b, and when the detector 72b reads the starting point (minimum scale value 0) of the first transport tray Tr1, the control unit Cu identifies 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 (an integer multiple of the interval between the detectors 72 (800)) according to the distance from the starting point detector 72a is assigned to each of the detectors 72 other than the starting point detector 72a and is stored in the control unit Cu.

[0029] When the first transport tray Tr1 is further transported along the transport path Tp1, the control unit Cu identifies the coordinates of the first transport tray Tr1 from the scale interval (e.g., 500) and offset value (800) of the scale 71 read by the detection unit 72b at that time (see FIG. 4(c)). Here, when the first transport tray Tr1 is further transported, the origin detection unit 72a moves out of the scale range of the transport tray Tr (the scale 71 and the detection unit 72 are not directly facing each other), but 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. At this time, because the detection unit 72b has read the scale interval of the scale 71, it is not necessary for the control unit Cu to issue an alarm or reset the error to the control components of the absolute encoder 7, and therefore there is no effect on identifying 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 graduations of the first transport tray Tr1 using each detection unit 72c, 72d, 72e, 72f, 72g, and 72h, and determines the coordinates of the transport tray Tr1 on the outgoing transport path Tp1 from the graduations and offset values ​​of the read scale 71 (see Figure 4(d), coordinates of the first transport tray Tr1).

[0030] In addition to the above, when the second transport tray Tr2 is transported on 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 on the outbound transport path Tp1 are identified. Note that, when identifying 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, and the quotient can be used to identify each transport tray Tr1 to Tr3, with the remainder being used to identify the coordinates. In this case, it is preferable for the minimum scale value of the scale 71 attached to each transport tray Tr1 to Tr3 to be an integer multiple, from the perspective of calculation processing.

[0031] 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 start point detector 72a reads the start 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 control unit Cu can determine that the second transport tray Tr2 is currently at a coordinate of 200 on the outgoing transport path Tp1 from the scale interval (e.g., 1200) read by the start point detector 72a (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 start 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, if the scale values ​​of the scale 71 for each of the transport trays Tr1 to Tr3 are set so as not to overlap with each other, the control unit Cu can determine the type of each of the transport trays Tr1 to Tr3 from the scale intervals read by each of the detection units 72. Thereafter, by repeating the above operation, the control unit Cu can identify the coordinates of each of the transport trays Tr on the outgoing transport path Tp1 and the return transport path Tp2 while identifying each of the transport trays Tr (Tr1 to Tr3) being transported on the outgoing transport path Tp1 and the return transport path Tp2.

[0032] According to the above embodiment, by connecting the detectors 72a-72o fixedly arranged in the position chamber Pc, the load lock chamber Lc, the processing chambers Vc1 and Vc2, and the 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 detector 72. Since this eliminates the need to route signal cables within each chamber Pc, Lc, Vc1, Vc2, and Bc, 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 detector 72, the number of parts can be reduced, which is advantageous.

[0033] 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, the control unit Cu can accurately determine the coordinates and type of each transport tray Tr1-Tr3 simply by reading the scale 71 again using one of the detectors 72a-72o after power supply is restored. This allows the control unit Cu to accurately determine the coordinates and type of each transport tray Tr1-Tr3, thereby advantageously enabling 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 1000, 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 advantageous in terms of production efficiency. This can be said to be a transport tray identification and absolute position detection system that utilizes the changeable combination of the scale 71 and detector 72 to immediately determine the identification and absolute position of each transport tray Tr1-Tr3.

[0034] Although the above describes an embodiment of the present invention, 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 point contact with the underside of the transport tray Tr in the Z-axis direction. However, this is not limited to this configuration, and other known types, such as spherical or magnetic levitation types, can also be used. While the above embodiment includes 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 the 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, the driving force can be reliably transmitted to the transport tray Tr by rolling contact.

[0035] 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 configuration 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 up-and-down movement in the Z-axis direction, and the rotation (pitching) around an axis in the Y-axis direction. Although not specifically illustrated or described, for example, rail members may be provided in the upper parts of the position chamber Pc, the load lock chamber Lc, and each processing chamber Vc1, Vc2, and sliders slidably engaged with the rail members may be provided, 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 unit 6 is also not limited to this configuration as long as it can limit to some extent the degrees of freedom in particular the rotation (roll) of the transport tray Tr around an axis in the front-back direction in the X-axis direction and the left-and-right movement in the Y-axis direction. A configuration similar to that of the first guide unit may be adopted. Furthermore, in the above embodiment, an example was described in which the transport tray Tr is transported in an upright position, but this is not limited to this, and the present invention can be applied regardless of the position of the transport tray Tr during transport. [Explanation of symbols]

[0036] VM...vacuum processing apparatus, Sw...substrate (substrate to be processed), Tr, Tr1 to Tr3...transport tray, Tm...transport means, 71...scale, 72a to 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

1. 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. 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.

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