WO2021188122A1

WO2021188122A1 - Substrate tray transfer system for substrate process equipment

Info

Publication number: WO2021188122A1
Application number: PCT/US2020/024947
Authority: WO
Inventors: Shinichi Kurita; Shinobu Abe; Chang Hee Shin; Masahiko Kowaka; Yong Kee Chae
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2020-03-20
Filing date: 2020-03-26
Publication date: 2021-09-23
Anticipated expiration: 2022-09-20
Also published as: JP2023517711A; EP4122005A1; JP7539993B2; TW202141676A; KR20220154807A; CN115335977A; EP4122005A4; TWI878497B; KR102863993B1

Abstract

A method and apparatus for a transfer robot for a substrate processing system is provided that includes a transfer chamber coupled to a plurality of processing chambers. The transfer chamber comprises a transfer robot comprising a base coupled to a support stem, and a tray cassette fixed to the base, wherein the tray cassette comprises a first tray carrier for holding and transferring a first tray from the tray cassette to a susceptor in one of the plurality of processing chambers and a second tray carrier stacked on the first tray carrier, the second tray carrier for holding a second tray, wherein each of the first tray carrier and the second tray carrier includes a plurality of friction reducing devices.

Description

SUBSTRATE TRAY TRANSFER SYSTEM FOR SUBSTRATE PROCESS EQUIPMENT

BACKGROUND

Field

[0001] Embodiments of the disclosure generally relate to a transfer system for transferring substrate trays in a processing system. More specifically, embodiments herein relate to a tray transfer system for transporting solar cell substrates in a processing system.

Description of the Related Art

[0002] Solar cells are photovoltaic (PV) devices that convert sunlight directly into electrical power. The most common solar cell material is silicon, in the form of single or multicrystalline substrates. Because the amortized cost of forming silicon-based solar cells to generate electricity is currently higher than the cost of generating electricity using traditional methods, it is desirable to reduce the cost to form solar cells using silicon substrates.

[0003] Currently, to form film layers on silicon substrates used for PV applications, multiple such substrates are positioned on a carrier or tray that is transferred between various processing chambers used to process the substrates or form film layers thereon. The tray of substrates is moved by using a robot having an end effector configured to convey thin, large surface area, substrates between process chambers in which film layers used in forming flat panel displays are formed on the large area substrate. However, the trays and silicon substrates are heavier than the large area substrates, and the end effectors repurposed from the flat panel display fabrication apparatus may fail, or must be reinforced to support and transfer the trays.

[0004] Thus, there is a need for an improved method and apparatus for transferring substrate trays and the substrates loaded thereon or therein. SUMMARY

[0005] Embodiments described herein provides a method and apparatus for a transfer robot for a substrate processing system that includes a transfer chamber coupled to a plurality of processing chambers. The transfer chamber comprises a transfer robot comprising a base coupled to a support stem, and a tray cassette fixed to the base, wherein the tray cassette comprises a first tray carrier for holding and transferring a first tray from the tray cassette to a susceptor in one of the plurality of processing chambers and a second tray carrier stacked on the first tray carrier, the second tray carrier for holding a second tray, wherein each of the first tray carrier and the second tray carrier includes a plurality of friction reducing devices.

[0006] In another embodiment, a transfer robot is provided that includes a base coupled to a support stem, and a tray cassette fixed to the base, wherein the tray cassette comprises a first tray carrier for holding and transferring a first tray from the tray cassette to a susceptor and a second tray carrier for holding a second tray, wherein each of the first tray carrier and the second tray carrier are stacked vertically and include a magnetic levitation assembly.

[0007] In another embodiment, a transfer robot is provided that includes a base coupled to a support stem, and a tray cassette fixed to the base, wherein the tray cassette comprises a first tray carrier for holding and transferring a first tray from the tray cassette to a susceptor and a second tray carrier for holding a second tray, wherein each of the first tray carrier and the second tray carrier are stacked vertically and include a roller assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. [0009] Figure 1 is a top plan view of a multi-chamber substrate processing system suitable for solar cell fabrication on substrates.

[0010] Figures 2A-2E are isometric views of a transfer robot showing various movement of the robot arms and trays.

[0011] Figure 3A is an isometric view of a tray cassette.

[0012] Figure 3B is a (front or rear) side view of the tray cassette.

[0013] Figure 3C is an enlarged detail view of a portion of the tray cassette of Figure 3B.

[0014] Figure 4A is a side view (front or rear) of the transfer robot with the tray cassette thereon.

[0015] Figure 4B is an enlarged view of a portion of the tray cassette shown in Figure 4A.

[0016] Figure 4C is an enlarged view of another portion of the tray cassette shown in Figure 4A.

[0017] Figures 5A and 5B are sectional views of a portion of the tray cassette, particularly a sectional view of the first tray carrier and the tray cassette, along lines 5A-5A and 5B-5B of Figure 3A, respectively.

[0018] Figure 6 is a schematic top view of the tray cassette and the tray showing a connection interface between the tray and the robot arm.

[0019] Figures 7A-7C are sectional views of the substrate processing system showing one embodiment of a tray transfer process.

[0020] Figures 8A and 8B are sectional views of the substrate processing system showing other portions of a tray transfer process.

[0021] Figures 9A-9D are schematic sectional views of the processing chamber showing one embodiment of the interaction of the lift pins and the magnet rail in the transfer process as described above.

[0022] Figure 9E is a schematic top plan view of the susceptor shown in Figures 9A and 9C showing the magnet rails thereof.

[0023] Figures 10A and 10B are sectional views of the substrate processing system showing another embodiment of a tray transfer process.

[0024] Figures 11A-11 D are schematic sectional views of the processing chamber showing another embodiment of the interaction of the lift pins and the tray rollers in the transfer process as described in Figures 10A and 10B. [0025] Figures 12A and 12B are sectional views of the substrate processing system showing another embodiment of a tray transfer process.

[0026] Figures 13A-13D are schematic sectional views of the processing chamber showing another embodiment of the interaction of the lift pins and the pin rollers in the transfer process shown in Figures 12A and 12B.

[0027] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION

[0028] Embodiments described herein provide a method and an apparatus for transferring trays that contain multiple substrates, such as a solar cell substrates made of silicon or other material suitable for photovoltaic device formation.

[0029] Figure 1 is a top plan view of a multi-chamber substrate processing system 100 suitable for solar cell fabrication on substrates. The system 100 includes a plurality of processing chambers 105 and one or more load lock chambers 110 positioned around a central transfer chamber 115. The processing chambers 105 are each configured to complete at least one of a number of different processing steps to achieve a desired processing of a plurality of substrates that are positioned on a tray (not shown). Each process chamber 105 may be configured to provide the same process, or a different process, as compared to another processing chamber 105. The tray is positioned on a tray carrier 120 (one is shown in dashed lines) that supports and transfers the tray. Another tray carrier is positioned below the tray carrier 120 that supports a tray with another plurality of substrates.

[0030] Positioned within the transfer chamber 115 is a transfer robot 125 having a multi-arm transfer assembly 128. One tray carrier 120, or two tray carriers 120, are positioned in a tray cassette (described below) positioned on the transfer robot 125. The transfer assembly 128 has two arms 130 and 135 that are independently operated to move an equal number of tray carriers 120 thereon (each capable of holding a single tray in a horizontal direction (X and/or Y directions)). The transfer robot 125 is movable about a rotational axis (in the Z direction). The transfer assembly 128 is configured to be supported and move independently of the transfer robot 125. Each of the arms 130 and 135 engage one of the tray carriers 120 to transfer individual trays.

[0031] The tray carrier 120 includes a plurality of friction reducing devices 140 adapted to support and facilitate movement of a tray supported thereon. In one embodiment, the transfer robot 125 is configured to be rotated about a vertical axis and/or linearly driven in a vertical direction (Z direction) while the arms 130 and 135 are configured to move linearly in a horizontal direction (X and/or Y direction) independent of and relative to the transfer robot 125. The movement of the arms 130 and 135 moves the respective tray carrier 120 relative to the friction reducing devices 140. The transfer robot 125 is adapted to align the one of the tray carriers 120 with sealable openings in the processing chambers 105 and the load lock chambers 110. When the transfer robot 125 is at a suitable elevation, one of the arms 130 and 135 is extended horizontally (X direction, Y direction or a combination thereof in a typically straight line path) to transfer and/or position a tray carrier 120, and transfer the supported tray thereon selectively into or out of any one of the processing chambers 105 and the load lock chambers 110. Additionally, the transfer robot 125 may be rotated to align the arms 130 and 135 and/or tray carriers 120 with others of the processing chambers 105 and the load lock chambers 110.

[0032] A portion of the interior of one of the processing chambers 105 is shownin Figure 1 to expose a substrate support or susceptor 150 therein that is adapted to receive and support one of the trays during processing. The susceptor 150 includes a plurality of lift pins 155, the tops of which are shown, that are movable relative to an upper surface of the susceptor 150 to facilitate transfer of the trays by lifting a tray of the tray carrier 120, or place it on the tray carrier 120, within the processing chamber 105 (or within the load lock chambers 110).

[0033] A portion of the processing chambers 105 has one or more friction reducing devices 160 at or near a chamber opening 170. The orientation of a friction reducing device 160 is the same as (e.g., parallel to), or orthogonal to, the orientation of the friction reducing devices 140 on the tray carrier 120 when in a transfer position therewith. The friction reducing device 140 provides movement of the trays off or onto the tray carrier 120, and into and out of the processing chambers 105 (i.e., off of and onto the tray carrier 120). The friction reducing device 160 enables movement of the trays into and out of the processing chambers 105, at least at the chamber opening 170, to facilitate movement of the trays onto or off of the susceptor 150.

[0034] The environment in the substrate processing system 100 is isolated from ambient pressure (i.e. pressure outside the system 100) and is maintained at a negative pressure (i.e., at a vacuum pressure compared to the outer environment) by one or more vacuum pumps (not shown). During processing, the processing chambers 105 are pumped down to pre-determined vacuum pressures configured to facilitate thin film deposition and other processes. Likewise, the transfer chamber 115 is held at a reduced or vacuum pressure during transfer of the trays to facilitate a minimal pressure gradient between the processing chambers 105 and the transfer chamber 115. In one embodiment, the pressure in the transfer chamber 115 is maintained at a pressure lower than ambient pressure. For example, the pressure in the transfer chamber may be about 7 Torr to about 10 Torr while the pressure in the processing chambers 105 may be lower. In one embodiment, the maintained pressure within the transfer chamber 115 is substantially equal to the pressure within the processing chambers 105 and/or load lock chambers 110 to facilitate a substantially equalized pressure in the system 100

[0035] Figures 2A-2E are isometric views of the transfer robot 125 showing various movements of the arms 130 and 135 thereof. The transfer robot 125 includes a base 202 that is supported in an elevated position on a support stem 203. One or more tray carriers 120 (shown as a first (upper) tray carrier 200A and a second (lower) tray carrier 200B) is supported by the base 202. Each of the first tray carrier 200A and the second tray carrier 200B is adapted to support and facilitate transfer of a single tray, shown in Figure 2D and Figure 2E as reference numeral 204A and 204B, respectively. While not shown for clarity in some Figures, the first tray carrier 200A and the second tray carrier 200B each are configured to operate with the trays 204A and 204B, respectively. Each of the trays 204A and 204B contain a plurality of substrates 205. [0036] Both of the first tray carrier 200A and the second tray carrier 200B comprise a tray cassette 206 that is configured to selectively simultaneously contain both of a tray 204A and a tray 204B. The tray cassette 206 includes an upper portion and a lower portion that each includes one or more friction reducing devices 140 as described in Figure 1 and will be discussed in further detail with respect to Figures 3A to 3C. The upper portion of the tray cassette 206 holds the first tray carrier 200A while the lower portion of the tray cassette 206 holds the second tray carrier 200B. The tray cassette 206, including the one or more friction reducing devices 140 (Figures 3A to 3C) for both of the upper portion and the lower portion, guides and facilitates transfer of the trays 204A and 204B, respectively, during movement of the arms 130 and 135, respectively. Movement of the tray 204A within the tray cassette 206 is independent of movement of the tray 204B, and vice versa, utilizing independent motion of the arms 130 and 135.

[0037] The support stem 203 is coupled to a motor (not shown) providing rotational movement of the base 202 (and the tray cassette 206) about a rotational axis 210. The support stem 203 is also adapted to move the base 202 (and the tray cassette 206) in a vertical (Z direction). Each of the arms 130 and 135 are coupled to individual drive systems (not shown) that enable movement thereof laterally across a length of the base 202 (in an X/Y plane). [0038] In Figure 2A, an extended member 207 of the arm 130 is adapted to contact the tray 204A (not shown) disposed on the first tray carrier 200A to move the tray 204A within the first tray carrier 200A laterally across the base 202 (X direction). Movement of the arm 130 and the extended member 207 coupled thereto across the tray cassette 206 in the -X and +X directions moves the tray 204A in the same direction. For example, movement of the arm 130 in the -X direction pushes the tray 204A out of the tray cassette 206. Likewise, movement of the arm 130 in the +X direction pulls the tray 204A into the tray cassette 206.

[0039] In Figure 2B, the arm 135 is adapted to contact the tray 204B (not shown) disposed on the second tray carrier 200B to move the tray 204B within the second tray carrier 200B laterally across the base 202 (X direction). Movement of the arm 135 across the tray cassette 206 in the -X and +X directions moves the tray 204B in the same direction. For example, movement of the arm 135 in the -X direction pushes the tray 204B out of the tray cassette 206. Likewise, movement of the arm 135 in the +X direction pulls the tray 204B into the tray cassette 206.

[0040] In Figure 2C, both of the arms 130 and 135 are in a “home” position. When present, the tray 204A (disposed on the first tray carrier 200A) and the tray 204B (disposed on the second tray carrier 200B) are fixed in the tray cassette 206. In this position, the transfer robot 125 can rotate and move both of the first tray carrier 200A (and tray 204A) and the second tray carrier 200B (and tray 204B) in the tray cassette 206 in a rotational motion. Additionally, the transfer robot 125 can move both of the first tray carrier 200A (and tray 204A) and the second tray carrier 200B (and tray 204B) in the tray cassette 206 vertically (+Z or -Z directions) to change the elevation of the base 202 and the tray cassette 206 located thereon.

[0041] In Figure 2D, the arm 130 is at maximum extension (and the arm 135 is at the home position shown in Figure 2C) which, in a transfer operation to deliver the tray 204A into a processing chamber 105 (a portion thereof is shown in dashed lines), moves the tray 204A to an end of the base 202 and out of the tray cassette 206 (i.e. , into the processing chamber 105). A portion of the arm 130 is sized to pass over and/or around the tray cassette 206. In a transfer operation to remove the tray 204A from the processing chamber 105, the arm 130 contacts the tray 204A in this position and moves (in the +X direction) the tray 204A back into the tray cassette 206 when the arm 130 is actuated.

[0042] In Figure 2E, the arm 135 is at maximum extension (and the arm 130 is at the home position shown in Figure 2C) which, in a transfer operation to deliver the tray 204B into a processing chamber 105 (shown in dashed lines), moves the tray 204B to an end of the base 202 and out of the tray cassette 206 (i.e., into the processing chamber 105). The arm 135 is sized to pass through the tray cassette 206. In a transfer operation to remove the tray 204B from the processing chamber 105, the arm 135 contacts the tray 204B in this position and moves the tray 204B back into the tray cassette 206 when the arm 135 is actuated (in the +X direction). [0043] Figures 3A-3C are various views of details of the tray cassette 206 as described herein. Figure 3A is an isometric view of the tray cassette 206. Figure 3B is a (front or rear) side view of the tray cassette 206. Figure 3C is an enlarged detail view of Figure 3B.

[0044] The tray cassette 206 includes a body 300 having two opposing major sides 302 and two opposing minor sides 304 extending between the opposed major sides 302. In one embodiment, the major sides 302 are larger, i.e., longer, than the length of the minor sides 304. However, in other embodiments, the major sides 302 are substantially equal in length to the length of the minor sides 304. The body 300 of the tray cassette 206 includes an upper portion 305 and a lower portion 310. The upper portion 305 and the lower portion 310 comprise the first tray carrier 200A and the second tray carrier 200B, respectively. As more clearly seen in Figure 3C, the tray 204A is positioned in the volume of the first tray carrier 200A and the tray 204B is positioned in the volume of the second tray carrier 200B.

[0045] The body 300 also includes a dimension 315A (length or width) that allows the arm 130 to pass thereacross or therearound. At least the lower portion 310 (first tray carrier 200A) of the body 300 includes a gap 312 having a width or length of that includes a sub-dimension 315B that allows the arm 135 to pass through the tray cassette 206.

[0046] The body 300 also includes a plurality of cross-members 320 between the major sides 302 thereof. Each of the first tray carrier 200A and the second tray carrier 200B include the plurality of cross-members 320. While the cross-members 320 of the first tray carrier 200A are one-piece (unitary) and extend between and are connected a their opposed ends to the opposed major sides 302, at least the cross-members 320 of the second tray carrier 200B are smaller and extend partially toward the opposed major sides 302 from a connection thereof with one of the major sides 302, and thus are formed as two- piece structures which include the gap 312 of dimension 315B between opposed, inwardly positioned, ends thereof. Thus, the gap 312 extends from a first end 325A of the body 300 to a second end 325B of the body 300 at least in the lower portion 310. [0047] Also shown in Figures 3A-3C are a plurality of friction reducing devices 140. The friction reducing devices 140 are included on both of the first tray carrier 200A and the second tray carrier 200B. Each of the friction reducing devices 140 may be magnetic devices, rollers (e.g., one or more roller assemblies) or wheels, or combinations thereof. The friction reducing devices 140 include outer, with respect to the width of the tray carries in the direction between the opposed major sides 302, friction reducing devices 330 and inner with respect to the width of the tray carries in the direction between the opposed major sides 302, friction reducing devices 335. The friction reducing devices 140 may be continuously or discontinuously formed from the first end 325A of the body 300 to the second end 325B of the body 300. For example, the friction reducing devices 140 may comprise a solid strip or linear pattern across the body 300, or discrete devices at specific locations across the body 300from the first end 325A to the second end 325B thereof. The friction reducing devices 140 enable reduced friction or no friction movement of the tray 204A and the tray 204B within the tray cassette 206 relative to the first tray carrier 200A and the second tray carrier 200B, respectively.

[0048] Figures 4A-4C are various views of the transfer robot 125 and tray cassette 206 showing one embodiment of the friction reducing devices 140 of the tray cassette 206 as described herein. Figure 4A is a side view (front or rear) of the transfer robot 125 with the tray cassette 206 thereon. Figure 4B is an enlarged view of a portion of the tray cassette 206 shown in Figure 4A. Figure 4C is an enlarged view of another portion of the tray cassette 206 shown in Figure 4A.

[0049] In this embodiment, the friction reducing devices 140 include a plurality of magnetic devices 400. The magnetic devices 400 are positioned in each of the first tray carrier 200A and the second tray carrier 200B. As will be described further herein, tray 204A is shown in the first tray carrier 200A and is magnetically levitated (i.e. , floating) relative to the cross-member 320 as shown in Figures 4B and 4C. The second tray carrier 200B shown in Figure 4A is empty but includes the magnetic devices 400 in order to support a tray (i.e., the tray 204B). [0050] Referring again to Figure 4A, the base 202 of the transfer robot 125 is coupled to the support stem 203 as described above, and the support stem 203 is coupled to an actuator 405. The actuator 405 moves the base 202 and supported tray cassette 206 in a vertical (Z direction) as well as turning it around the rotational axis 210. The arm 130 (for moving the tray 204A in first tray carrier 200A) is coupled to a first linear drive 410. The arm 135 (for moving a tray (not shown) in the second tray carrier 200B) is coupled to a second linear drive 415. The first linear drive 410 and the second linear drive 415 include stepper motors, belt drives, lead screws attached to motors such as stepper motors or other linear motors or devices to move the arms 130 and 135 in the X direction. Each of the first linear drive 410 and the second linear drive 415 as well as the actuator 405, is coupled to a controller 420. The controller 420 controls movement of the arms 130 and 135 independently in the X direction, the base 202 in the Z direction, and rotation of the base 202.

[0051] Also shown in Figure 4A, the arm 130 is coupled to a rectangular frame 425. The rectangular frame 425 defines a space 430 that is sized to pass over and around the tray cassette 206.

[0052] The rectangular frame 425 also positions the arm 130 vertically (in the Z direction) such that the arm 130 is aligned vertically with the tray 204A for pushing or pulling the tray laterally (in the X direction). The rectangular frame 425 is coupled to the first linear drive 410 to move the arm 135 and the tray 204A in the X direction. The arm 130 is disposed on a spacer 440. The spacer 440 is coupled to the second linear drive 415 to move the arm 130 and a tray (not shown) in the X direction. The spacer 440 also positions the arm 135 vertically (in the Z direction) such that the arm 135 is aligned with the tray (when a tray is present) vertically for pushing or pulling the tray laterally (in the X direction). The spacer 440 is coupled to the second linear drive 415 to move the arm 130 and a tray in the X direction.

[0053] Materials for the transfer robot 125 and the tray cassette 206 includes materials with low thermal conductivity as well as low coefficients of thermal expansion. Example materials for the transfer robot 125 and the tray cassette 206 includes stainless steel, aluminum, carbon fiber or graphite. In one specific example, the arms 130 and 135 and the tray cassette 206 can be stainless steel, aluminum or carbon fiber. The tray 204A and the tray 204B should be made of a material that has good mechanical stiffness and thermal conductance, and a lower CTE. In one example, the tray 204A and the tray 204B may be made of a carbon composite material, an Al-SiC composite material, Al, Invar®, or some combination or alloy thereof.

[0054] Each of the magnetic devices 400 include a linear rail 445 according to one embodiment. The linear rails 445 are continuous along the X direction of each of the first tray carrier 200A and the second tray carrier 200B. Referring to Figure 4B, the linear rails 445 are coupled to a sidewall 450 of the tray cassette 206 by a bracket 455. The bracket 455 includes a first magnet 460A and the tray 204A includes a second magnet 460B. The second magnet 460B is disposed in a housing 465 (shown in Figure 4C) that is fastened to the tray 204A. As shown in Figure 4C, the magnetic devices 400 interior of the magnetic devices 400 adjacent to the sidewalls 450 of the tray cassette 206 are disposed in a housing 470 that is fastened to the cross-members 320. The first magnet 460A and the second magnet 460B are positioned such that the poles thereof repel each other. In some embodiments, the second magnets 460B include a coating 475. As the tray 204A (and the tray 204B) are subject to processing environments that include plasma conditions, the coating 475 is a plasma resistant or plasma compatible material, such as aluminum.

[0055] Figures 5A and 5B are sectional views of a portion of the tray cassette 206, particularly a sectional view of the first tray carrier 200A and the tray cassette 206, along lines 5A-5A and 5B-5B of Figure 3A, respectively. Figures 5A and 5B show one embodiment of a magnetic levitation assembly 500 for the tray 204A. While not shown, the second tray carrier 200B and tray 204B includes the magnetic levitation assembly 500.

[0056] The sections of the tray cassette 206 and the first tray carrier 200A are shown at different locations thereof in Figures 5A and 5B to show different portions of the magnetic levitation assembly 500. The magnetic levitation assembly 500 shown in Figure 5A may alternate with the magnetic levitation assembly 500 shown in Figure 5B along a length (X direction) of the sidewall 450 of the tray cassette 206. [0057] The magnetic levitation assembly 500 shown in Figures 5A and 5B includes the first magnet 460A embedded in the bracket 455 that is coupled to the sidewall 450 of the tray cassette 206. The first magnet 460A may be a continuous strip along the length (X direction) of the sidewall 450 of the tray cassette 206 and or the bracket 455.

[0058] In Figure 5A, the magnetic levitation assembly 500 includes the second magnet 460B positioned within a housing 505 (a magnet housing) that is coupled to a first (lower) surface 510 of the tray 204A. The first surface 510 of the tray 204A is opposite to a second (upper) surface 515 thereof. The second surface 515 includes a plurality of pockets 520 formed therein that each pocket defines a recess in the outline of a substrate to support a substrate (not shown) therein. In Figure 5B, the magnetic levitation assembly 500 includes a side roller 525. The side roller 525 is coupled to the housing 505 (a roller housing). The side roller 525 is utilized to reduce contact, and thus friction, between the bracket 455 and the tray 204A as well as maintain a spacing therebetween when the tray 204A is moving within the tray cassette 206. The housing 505 extends along a length (X direction) of the tray 204A and includes a plurality of magnet housings that alternate with a plurality of roller housings. Thus, the tray 204A includes a plurality of second magnets 460B and a plurality of side rollers 525.

[0059] The housing 505 may be made of a non-ferrous material such as aluminum in order to protect the second magnet 460B from processing conditions where the tray 204A will be placed for processing of the substrates. The housing 505 is coupled to the tray 204A using fasteners 530 or other suitable joining method.

[0060] The magnetic levitation assembly 500 shown in figure 5A forms a lateral offset distance 535 between the first magnet 460A and the second magnet 460B. The lateral offset distance 535 may be about 2 millimeters (mm) to about 3 mm. The first magnet 460A and the second magnet 460B provide a gap 540 between the bracket 455 and the housing 505. The gap 540 may be about 1 mm to about 3 mm and is based on the strength of the magnets 460A, B and the mass of the tray 204A or B and the substrates thereon, and can be modified or chosen based on those parameters. [0061] Figure 6 is a schematic top view of the tray cassette 206 and the tray 204A showing a connection interface 600 between the tray 204A and the arm 130. While not shown, the tray 204B and the arm 135 includes the connection interface 600.

[0062] The connection interface 600 includes one or more coupling devices 605 that enable a secure connection between the arm 130 and an end 610 of the tray 204A. The connection interface 600 can selectively connect or disconnect the arm 130 from the tray 204A to enable movement of or securing the tray 204A relative to the tray cassette 206. Each of the one or more coupling devices 605 include a magnetic connection or a mechanical connection. The magnetic connection may include an electromagnet positioned on the arm 130 or the tray 204A that is selectively attracted to a magnetic component positioned in an opposing relationship on the tray 204A or the arm 130. A controller is utilized to control the actuation of the electromagnet. The mechanical connection may be a pin/slot arrangement on the tray 204A and/or the arm 130. The mechanical connection may be controlled by moving the tray 204A relative to the arm 130 to connect/disconnect the pin and the slot.

[0063] Figures 7A-7C are sectional views of the substrate processing system 100 showing one embodiment of a tray transfer process. The substrate processing system 100 shown in Figures 7A and 7C includes a processing chamber 105 and a load lock chamber 110 coupled to the central transfer chamber 115. Figure 7B is an enlarged view of the central transfer chamber 115 and the processing chamber 105 shown in Figure 7A.

[0064] The processing chamber 105 includes a susceptor 150 having a plurality of lift pins 155 provided in openings in the susceptor 150. The susceptor 150 is coupled to support stem 700 and a motor 755. The motor 755 moves the susceptor 150 vertically (in the Z direction) to lower and raise it within the processing chamber 105.

[0065] The central transfer chamber 115 includes the transfer robot 125 and the tray cassette 206 mounted thereon. Figures 7A and 7B show the arm 130 extended through the chamber opening 170 to transfer the tray 204A out of the tray cassette 206 and into the processing chamber 105. [0066] As shown in Figure 7B, the lift pins 155 are extended a distance above a support surface 710 of the susceptor 150 when the susceptor is in the lowered position within the process chamber 105 of Figure 7B. The support surface 710 is at least partially surrounded by a shoulder 715 where the tray 204A will be placed.

[0067] When the susceptor 150 is lowered as shown in Figure 7B, the lift pins 155 contact a bottom 720 of the processing chamber 105 which results in the upper ends of the lift pins 155 extending above the support surface 710. The lift pins 155 support a magnet rail 725 in one embodiment. The magnet rail 725, in conjunction with the magnets 460B in the trays (tray 204A, B) magnetically levitates the tray 204A in the processing chamber 105. When the susceptor 150 is lifted (in the Z direction), the lift pins 155, which are movably disposed in openings 730 formed through the susceptor 150, and the magnet rail 725 moves closer to the support surface 710. When the susceptor 150 is raised to a certain distance, the tray 204A will contact the support surface 710, and the shoulder 715 prevents movement of the tray 204A during processing. The magnet rail 725 is configured to contact the support surface 710 as the tray contacts the surface of the susceptor 150.

[0068] Transfer of the tray 204A from the arm 130 to the magnet rail 725 on the susceptor 150 is provided by detaching the connection interface 600. When the connection interface 600 is magnetic, electromagnets (i.e., the coupling devices 605) are denergized to release the tray 204A from the arm 130. When the connection interface 600 is a mechanical connection, a pin/hole connection (i.e., the coupling devices 605) is decoupled. Decoupling is provided by relative vertical movement (in the Z direction) by moving the transfer robot 125 and arm 130 upward (in the Z direction). Once the tray 204A is decoupled at the connection interface 600, the arm 130 is retracted back into the central transfer chamber 115 as shown in Figure 7C. A valve 735, such as a slit valve mechanism, then seals the processing chamber 105 from the central transfer chamber 115 to enable processing in the processing chamber 105. Removing the tray 204A is accomplished by reversing the transfer steps as described above. [0069] In one embodiment, the chamber opening 170 includes friction reducing devices 160 embedded in or disposed on a body thereof. For example, a magnet device 740 is included in or on a body 745 of the central transfer chamber 115 adjacent to the chamber opening 170. A magnet device 740 is also shown in body 750 of the processing chamber 105 adjacent to the chamber opening 170. The friction reducing devices 160 provide a magnetic repulsion to levitate the tray 204A when passing through the chamber opening 170.

[0070] Figures 8A and 8B are sectional views of the substrate processing system 100 showing other portions of a tray transfer process. Figure 8A shows the transfer robot 125 in a vertical position to align the tray cassette 206 such that the second tray carrier 200B is aligned with the chamber opening 170. In this position, in which the transfer robot 125 is at a higher elevation than that shown in Figure 7A, the tray 204B (not shown but inside the second tray carrier 200B) may be transferred into the processing chamber 105 through the chamber opening 170. The transfer process is similar to the process described in Figures 7A-7C. Figure 8B shows the transfer robot 125 rotated along the rotational axis 210 to transfer the tray 204B into a slot of the load lock chamber 110. As shown, the arm 135 is extended into a chamber opening 800 to place the tray 204B therein.

[0071] Figures 9A-9D are schematic sectional views of the processing chamber 105 showing one embodiment of the interaction of the lift pins 155 and the magnet rail 725 in the transfer process as described above. In these Figures, a tray 900 is shown which may be either of the trays 204A and 204B as described herein. The view of the processing chamber 105 in Figures 9A-9D is rotated 90 degrees from the view shown in Figures 7A-8C.

[0072] Figure 9E is a schematic top plan view of the susceptor 150 shown in Figures 9A and 9C showing the magnet rails 725.

[0073] Figure 9A shows the susceptor 150 in a transfer position wherein the lift pins 155 are contacting the bottom 720 and the magnet rails 725, positioned on each of the lift pins 155, are elevated from the support surface 710 of the susceptor 150. Figure 9B is an enlarged view of a portion of the susceptor 150 and the tray 900 of Figure 9A. Figure 9C shows the susceptor 150 in a processing position wherein the tray 900 is resting on the support surface 710 of the susceptor 150. Figure 9D is an enlarged view of a portion of the susceptor 150 and the tray 900 of Figure 9C.

[0074] The magnet rail 725 includes a plurality of magnets 905 attached to an upper surface of each of the lift pins 155. The lift pins 155 include central or inner lift pins 910 and peripheral or outer lift pins 915. In one embodiment, each of the rows include a plurality of magnets 905 (in the X direction) and each of the rows of outer lift pins 915 include a plurality of magnets 905 (in the X direction).

[0075] In some embodiments, the plurality of magnets 905 form a magnet rail as described above and the susceptor 150 includes a plurality of grooves formed therein to receive the magnet rail. A portion of the lift pins 155 are coupled to each other by a connector plate 920. For example, at least a portion of the inner lift pins 910 are coupled to a portion of the outer lift pins 915 to keep the position of the plurality of magnets 905 parallel to a groove formed in the susceptor 150.

[0076] In Figure 9C, the susceptor 150 is raised in the Z direction which allows the magnets 905 to recess into the openings 730 formed through the susceptor 150. This allows the tray 900 to rest on the support surface 710 of the susceptor 150 for processing.

[0077] In Figures 9B and 9D, the outer lift pins 915 include a bracket 925 attached thereto. The bracket 925 includes a magnet 930. The bracket 925 may span the length of the tray 900 (in the X direction) or be discrete segments attached to each of the outer lift pins 915. In one embodiment, the bracket 925 is couplable with the arms 130 or 135 (shown in other Figures) such that the bracket 925 (on both sides of the tray 900 in some embodiments) moves with the tray 900 during transfer using the transfer robot 125. In Figure 9E, the bracket 925 is slightly longer than the magnet rail 725. This allows the bracket 925 to be accessible to the robot arms 130 or 135.

[0078] The openings 730 of the susceptor 150 for the outer lift pins 915 include an enlarged opening or channel 935 that receives the bracket 925 when the susceptor 150 is in a processing position. When the bracket 925 is disposed in the channel 935 as shown in Figure 9D, the tray 900 is resting on the support surface 710 of the susceptor 150 for processing.

[0079] Figures 10A and 10B are sectional views of the substrate processing system 100 showing another embodiment of a tray transfer process. The substrate processing system 100 shown in Figures 10A and 10B is similar to the embodiment shown in Figures 7A and 7B except the magnet devices (e.g., the magnetic levitation assembly 500 (shown in figure 5A)) is replaced with a plurality of tray rollers 1000 (e.g., a roller assembly). Thus, the plurality of friction reducing devices 140 described in Figures 1-2E includes the tray rollers 1000. Similar to Figure 7A, the substrate processing system 100 includes a processing chamber 105 and a load lock chamber 110 coupled to the central transfer chamber 115. Figure 10B is an enlarged view of the central transfer chamber 115 and the processing chamber 105 shown in Figure 10A. Reference numerals that are common to Figures 7A and 7B will not be repeated for brevity. Additionally, other views of the tray transfer process shown in Figures 7C-9D (using the magnetic levitation system) are not shown as the tray transfer process described in the following Figures will operate similarly unless otherwise noted.

[0080] In Figures 10A and 10B, the tray rollers 1000 are shown coupled to the trays 204A and 204B. However, in other Figures below, rollers are coupled to the tray cassette 206 (in the central transfer chamber 115) and coupled to each of the lift pins 155 (in the processing chamber 105).

[0081] Figures 10A and 10B show the arm 130 extended through the chamber opening 170 to transfer the tray 204A out of the tray cassette 206 and into the processing chamber 105.

[0082] As shown in Figure 10B, the tray rollers 1000 on the tray 204A are aligned with the lift pins 155 of the susceptor 150. When the susceptor 150 is lifted (in the Z direction), the lift pins 155, which are movably disposed in openings 730 formed through the susceptor 150, the tray rollers 1000 retract into the openings 730. Thus, the tray 204A will contact the support surface 710 for processing. Before releasing the tray 204A, the susceptor 150 can be actuated vertically (up) a small distance to position the tray rollers at least partially into the openings 730 to prevent the tray 204A from rolling off of the susceptor 150.

[0083] Transfer of the tray 204A from the arm 130 to the susceptor 150 is provided by detaching the connection interface 600. In this embodiment, the connection interface 600 is a mechanical connection, for example, a pin/hole connection. Decoupling is provided by relative vertical movement (in the Z direction) by moving the transfer robot 125 and arm 130 upward (in the Z direction). Once the tray 204A is decoupled at the connection interface 600, the arm 130 is retracted back into the central transfer chamber 115. The valve 735, such as a slit valve mechanism, then seals the processing chamber 105 from the central transfer chamber 115 to enable processing in the processing chamber 105. Removing the tray 204A is accomplished by reversing the transfer steps as described above.

[0084] Figures 11A-11 D are schematic sectional views of the processing chamber 105 showing one embodiment of the interaction of the lift pins 155 and the tray rollers 1000 in the transfer process as described above. In these Figures, a tray 900 is shown which may be either of the trays 204A and 204B as described herein. The view of the processing chamber 105 in Figures 11A-11 D is the same as the orientation shown in Figures 10A-10B. Figures 11A-11 D are similar to the embodiment shown in Figures 9A-9D and reference numerals common to both sets of Figures will not be explained in detail for brevity.

[0085] Figure 11A shows the susceptor 150 in a transfer position wherein the tray rollers 1000 are positioned over the lift pins 155, which are elevated from the support surface 710 of the susceptor 150. Figure 11 B is an enlarged view of a portion of the susceptor 150 and the tray 900 of Figure 11 A. Figure 11 C shows the susceptor 150 in a processing position wherein the tray 900 is resting on the support surface 710 of the susceptor 150. Figure 11 D is an enlarged view of a portion of the susceptor 150 and the tray 900 of Figure 11 C. .

[0086] In contrast to the detailed Figures 9B and 9D described above, the susceptor 150 includes a ramp 1100. The ramp 1100 smooths the transition between the susceptor 150 and a surface 1105 of the chamber opening 170. For example, the ramp 1100 allows the tray rollers 1000 to move from an elevation of the chamber opening 170 to an elevation of the susceptor 150 if the elevations are different. The ramp 1100 may also form a portion of the shoulder 715 (shown in Figure 7B).

[0087] As shown in Figure 11 B, the tray rollers 1000 are coupled to the tray 204A by a bracket 1110. The tray rollers 1000 are coupled to the bracket 1110 by an axle 1115.

[0088] In Figure 11 C and 11 D, the tray 204A is resting on the susceptor 150 in a processing position. The tray rollers 1000 are recessed into the openings 730 formed in the susceptor 150. As shown in Figure 11 D, a gap 1120 is provided between the upper surface of the lift pins 155 and the outer surface of the tray rollers 1000. The gap 1120 may be about 3 mm to about 6 mm, such as about 5 mm.

[0089] Figures 12A and 12B are sectional views of the substrate processing system 100 showing another embodiment of a tray transfer process. The substrate processing system 100 shown in Figures 12A and 12B is similar to the embodiment shown in Figures 10A and 10B except the tray rollers 1000 are replaced with a plurality of tray cassette rollers 1200 in the transfer robot 125. Thus, the plurality of friction reducing devices 140 described in Figures 1-2E includes the tray cassette rollers 1200. Similar to Figures 7A and 10A, the substrate processing system 100 includes a processing chamber 105 and a load lock chamber 110 coupled to the central transfer chamber 115. Figure 12B is an enlarged view of the central transfer chamber 115 and the processing chamber 105 shown in Figure 12A. Reference numerals that are common to Figures 7A and 7B (and/or Figures 10A and 10B) will not be repeated for brevity. Additionally, other views of the tray transfer process shown in Figures 7C-9D (using the magnetic levitation system) are not shown as the tray transfer process described in the following Figures will operate similarly unless otherwise noted.

[0090] In the central transfer chamber 115, the tray cassette rollers 1200 are coupled to the tray cassette 206. In the processing chamber 105, the susceptor 150 includes pin rollers 1205. Thus, the lift pins 155 include a roller head attached to an upper surface thereof. [0091] Figures 12A and 12B show the arm 130 extended through the chamber opening 170 to transfer the tray 204A out of the tray cassette 206 and into the processing chamber 105.

[0092] As shown in Figure 12B, when the susceptor 150 is lifted (in the Z direction), the lift pins 155 and the pin rollers 1205, which are movably disposed in openings 730 formed through the susceptor 150, the pin rollers 1205 retract into the openings 730. Thus, the tray 204A will contact the support surface 710 for processing.

[0093] Transfer of the tray 204A from the arm 130 to the susceptor 150 is provided by detaching the connection interface 600. In this embodiment, the connection interface 600 is a mechanical connection, for example, a pin/hole connection. Decoupling may be provided by relative vertical movement (in the Z direction) by moving the transfer robot 125 and arm 130 upward (in the Z direction). Once the tray 204A is decoupled at the connection interface 600, the arm 130 is retracted back into the central transfer chamber 115. The valve 735, such as a slit valve mechanism, then seals the processing chamber 105 from the central transfer chamber 115 to enable processing in the processing chamber 105. Removing the tray 204A is accomplished by reversing the transfer steps as described above.

[0094] Figures 13A-13D are schematic sectional views of the processing chamber 105 showing one embodiment of the interaction of the lift pins 155 and the pin rollers 1205 in the transfer process as described above. In these Figures, a tray 900 is shown which may be either of the trays 204A and 204B as described herein. The view of the processing chamber 105 in Figures 13A-13D is the same as the orientation shown in Figures 12A-12B. Figures 13A-13D are similar to the embodiment shown in Figures 11A-11 D and reference numerals common to both sets of Figures will not be explained in detail for brevity.

[0095] Figure 13A shows the susceptor 150 in a transfer position wherein the lift pins 155 and the pin rollers 1205 are elevated from the support surface 710 of the susceptor 150. Figure 13B is an enlarged view of a portion of the susceptor 150 and the tray 900 of Figure 13A. Figure 13C shows the susceptor 150 in a processing position wherein the tray 900 is resting on the support surface 710 of the susceptor 150. Figure 13D is an enlarged view of a portion of the susceptor 150 and the tray 900 of Figure 13C.

[0096] In contrast to Figures 11 B and 11 D described above, the chamber opening 170 includes a transition roller 1300. The transition roller 1300 smooths the transition between the susceptor 150 and a surface 1105 of the chamber opening 170. For example, the transition roller 1300 allows the tray 204A to move from an elevation of the chamber opening 170 to an elevation of the susceptor 150 if the elevations are different. The transition roller 1300 is an example of the one or more friction reducing devices 160 described above.

[0097] In Figure 13C and 13D, the tray 204A is resting on the susceptor 150 in a processing position. The pin rollers 1205 are recessed into the openings 730 formed in the susceptor 150.

[0098] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

Claims:

1. A substrate processing system, comprising: a transfer chamber coupled to a processing chamber, wherein the processing chamber includes a susceptor therein, the transfer chamber comprising: a transfer robot comprising a base coupled to a support stem; and a tray cassette fixed to the base, wherein the tray cassette comprises a first tray carrier for holding and transferring a first tray from the tray cassette to a susceptor in the processing chamber and a second tray carrier stacked on the first tray carrier, the second tray carrier for holding a second tray, wherein each of the first tray carrier and the second tray carrier include a plurality of friction reducing devices.

2. The system of claim 1 , wherein each of the plurality of friction reducing devices includes a magnetic levitation assembly.

3. The system of claim 1 , wherein each of the plurality of friction reducing devices includes one or more magnets coupled to each of the first tray carrier and the second tray carrier.

4. The system of claim 3, wherein the one or more magnets comprises a linear rail.

5. The system of claim 4, wherein the linear rail comprises a plurality of linear rails.

6. The system of claim 1 , wherein each of the plurality of friction reducing devices includes a roller assembly.

7. The system of claim 6, wherein the roller assembly comprises a plurality of rollers coupled to each of the first tray carrier and the second tray carrier.

8. The system of claim 1 , wherein the one of the plurality of processing chambers includes an opening having a friction reducing device positioned therein.

9. The system of claim 8, wherein the friction reducing device comprises one or more magnets.

10. The system of claim 8, wherein the friction reducing device comprises one or more rollers.

11. A transfer robot, comprising: a base coupled to a support stem; and a tray cassette fixed to the base, wherein the tray cassette comprises a first tray carrier for holding and transferring a first tray from the tray cassette to a susceptor and a second tray carrier for holding a second tray, wherein each of the first tray carrier and the second tray carrier are stacked vertically and include a magnetic levitation assembly.

12. The system of claim 11 , wherein the magnetic levitation assembly includes one or more magnets coupled to each of the first tray carrier and the second tray carrier.

13. The system of claim 12, wherein the one or more magnets comprises a linear rail.

14. The system of claim 13, wherein the linear rail comprises a plurality of linear rails.

15. The system of claim 11 , wherein each of the first tray carrier and the second tray carrier include a plurality of cross-members.