Patent Application
20240038565
The disclosure of Japanese Patent Application No. 2022-119717 filed on Jul. 27, 2022 including specification, drawings and claims is incorporated herein by reference in its entirety.
This invention relates to a centering technique for horizontally moving and positioning a substrate such that a center of the substrate is aligned with a center of a substrate support with the disk-like substrate provided with a cut such as a notch in a peripheral edge part placed in a horizontal posture on the upper surface of the substrate support and a substrate processing apparatus for processing a substrate using the centering technique. This process includes a bevel etching process.
In a known substrate processing apparatus, a chemical liquid process or a cleaning process is performed by supplying a processing liquid to a peripheral edge part of a substrate such as a semiconductor wafer while rotating the substrate. In an apparatus described in Japanese Patent Application Laid-Open No. 2019-149423, for example, a substrate is held under suction while being supported from below by a spin chuck (corresponding to an example of a “substrate support” of the present invention). In this case, misalignment between the center of the spin chuck and the center of the substrate decreases processing quality. In response to this, the above-described apparatus performs what is called a centering operation of reducing the amount of decentering of the substrate from the spin chuck before implementation of the process on the substrate.
The above-described conventional apparatus performs the centering operation in two stages. First, the amount of decentering i.e. eccentricity of the substrate from the spin chuck is measured. Next, the substrate on the spin chuck is pushed horizontally with a pusher to move the center of the substrate toward the center (rotary axis) of the spin chuck. Hence, room for improvement is left in terms of throughput.
Accordingly, a technique for performing the centering process without measuring the eccentricity amount is being studied. More particularly, three or more contact members are provided to surround the spin chuck in a horizontal plane. The contact members sandwich the substrate by moving toward an end face of the substrate in mutually different directions with the substrate placed on the spin chuck. In this way, the center of the disk-like substrate placed on the upper surface of the spin chuck can be aligned with the center of the spin chuck only by movements of the contact members.
However, if the substrate is provided with the cut such as a notch, centering accuracy is different depending on the configurations of the contact members as described in detail later with reference to
This invention was developed in view of the above problem and aims to enhance centering accuracy in a centering device using three or more contact members provided to surround a substrate support having a disk-like substrate having a cut in a peripheral edge part placed thereon in a horizontal plane and a substrate processing apparatus using the centering device.
A first aspect of the invention is a centering device for horizontally moving and positioning a substrate such that a center of the substrate is aligned with a center of a substrate support with the disk-like substrate provided with a cut in a peripheral edge part placed in a horizontal posture on an upper surface of the substrate support. The device comprises: three or more contact members each having a contact surface capable of contacting an end face of the substrate, the three or more contact members being arranged to surround the substrate support in a horizontal plane in such a posture that the contact surfaces face the end face of the substrate; a moving mechanism configured to move the contact members toward the substrate in mutually different directions; and a controller configured to control the moving mechanism to sandwich the substrate by moving the contact members toward the substrate. Each contact surface is finished such that a contactable region formed to intersect the horizontal plane has a linear shape or a curved shape having a center of curvature on the substrate side and having a radius of curvature larger than a radius of the substrate and is longer than an arc formed by cutting out a circumference of the substrate by the cut.
A second aspect of the invention is a substrate processing apparatus. The apparatus comprises: a substrate support having an upper surface configured to support a disk-like substrate provided with a cut in a peripheral edge part in a horizontal posture; the centering device; a suction unit configured to suck and hold the substrate on the substrate support by exhausting air between the substrate positioned by the centering device and the substrate support; a rotation driver configured to rotate the substrate support sucking and holding the substrate about a center of the substrate support; and a processing liquid supply mechanism configured to supply a processing liquid to the peripheral edge part of the substrate rotated about the center of the substrate support integrally with the substrate support.
In the invention thus configured, three or more contact members each having the contact surface capable of contacting the end face of the substrate are provided. These contact members are arranged to surround the substrate support in the horizontal plane with the contact surfaces facing the end face of the substrate. These contact members move toward the substrate in the mutually different directions to sandwich the substrate. At this time, if the contact surface is facing the cut of the substrate, there is an influence of the cut. However, in the invention, the contact surface is finished such that the contactable region formed to intersect the horizontal plane has the linear shape or the curved shape having the center of curvature located on the substrate side and having the radius of curvature larger than the radius of the substrate and is longer than the arc formed by cutting out the circumference of the substrate by the cut. This can prevent a part of the contact member from entering the cut, with the result that the influence of the cut on centering accuracy is suppressed.
According to the invention, centering accuracy can be enhanced.
All of a plurality of constituent elements of each aspect of the invention described above are not essential and some of the plurality of constituent elements can be appropriately changed, deleted, replaced by other new constituent elements or have limited contents partially deleted in order to solve some or all of the aforementioned problems or to achieve some or all of effects described in this specification. Further, some or all of technical features included in one aspect of the invention described above can be combined with some or all of technical features included in another aspect of the invention described above to obtain one independent form of the invention in order to solve some or all of the aforementioned problems or to achieve some or all of the effects described in this specification.
The indexer robot 122 includes a base 122a fixed to an apparatus housing, an articulated arm 122b provided rotatably about a vertical axis with respect to the base 122a, and a hand 122c mounted on the tip of the articulated arm 122b. The hand 122c is structured such that the substrate S can be placed and held on the upper surface thereof. Such an indexer robot including the articulated arm and the hand for holding the substrate is not described in detail since being known.
The substrate processing station 110 includes a substrate conveyor robot 111 arranged substantially in a center in a plan view and a plurality of processing units 1 arranged to surround this substrate conveyor robot 11. Specifically, the plurality of (eight in this example) processing units 1 are arranged to face a space where the substrate conveyor robot 111 is arranged. The substrate conveyor robot 111 randomly accesses these processing units 1 and transfers the substrates W. On the other hand, each processing unit 1 performs a predetermined processing to the substrate S. In this embodiment, these processing units 1 have the same function. Thus, a plurality of the substrates W can be processed in parallel. In the embodiment, one of the processing units 1 corresponds to the substrate processing apparatus 10 according to the invention.
The substrate holder 2 includes a spin base 21 that is a member of a smaller circular plate shape than the substrate S. The spin base 21 is supported on a rotary support shaft 22 extending downward from a central part of a lower surface of the spin base 21 in such a manner as to locate an upper surface 211 of the spin base 21 horizontally. The rotary support shaft 22 is rotatably supported by a rotary driver 23. The rotary driver 23 includes a built-in rotary motor 231. The rotary motor 231 rotates in response to a control command from the control unit 9. In response to receipt of resultant rotary driving force, the spin base 21 rotates about a vertical axis AX (alternate long and short dashed lines) extending in a vertical direction while passing through a center 21C of the spin base 21. In
The upper surface 211 of the spin base 21 has a dimension by which the substrate S is supportable to allow the substrate S to be placed on the upper surface 211 of the spin base 21. Although not shown in the drawings, the upper surface 211 is provided with a plurality of suction holes or suction grooves, for example. Such suction holes or grooves are connected to a suction pump 24 through a suction pipe 241. In response to a control command from the control unit 9, the suction pump 24 operates to apply suction power from the suction pump 24 to the spin base 21. As a result, air is exhausted from between the upper surface 211 of the spin base 21 and a lower surface of the substrate S, thereby holding the substrate S under suction on the spin base 21. Together with the rotation of the spin base 21, the substrate S held under suction in this way rotates about the vertical axis AX. Hence, the occurrence of misalignment between a center SC of the substrate S and the center 21C of the spin base 21, namely, decentering of the substrate S reduces the quality of the bevel etching process.
In response to this, the centering mechanism 3 is provided in the present embodiment. The centering mechanism 3 performs a centering operation while suction using the suction pump 24 is stopped (namely, while the substrate S is horizontally movable on the upper surface 211 of the spin base 21). As a result of implementation of the centering operation, the above-described decentering is eliminated to make alignment between the center SC of the substrate S and the center 21C of the spin base 21. The configuration and operation of the centering mechanism 3 will be described later in detail.
The processing liquid supply mechanism 4 is provided to perform the bevel etching process on the substrate S after implementation of the centering operation on the substrate S. The processing liquid supply mechanism 4 includes a processing liquid nozzle 41, a nozzle mover 42 that moves the processing liquid nozzle 41, and a processing liquid supplier 43 that supplies a processing liquid to the processing liquid nozzle 41. The nozzle mover 42 moves the processing liquid nozzle 41 between a retreat position to which the processing liquid nozzle 41 retreats laterally from a position above the substrate S as indicated by solid lines in
The processing liquid nozzle 41 is connected to the processing liquid supplier 43. When a suitable processing liquid is supplied from the processing liquid supplier 43 to the processing liquid nozzle 41 located at the processing position, the processing liquid is ejected from the processing liquid nozzle 41 onto a peripheral edge part of the rotating substrate S. By doing so, the bevel etching process with the processing liquid is performed on the entire peripheral edge part of the substrate S.
Although not shown in
The configuration of the centering mechanism 3 will be described next by referring to
The moving mechanism 34 includes a single mover 35 for moving the contact member 31, and a multi-mover 36 for moving the contact members 32 and 33 collectively. The single mover 35 is arranged closer to the X2 direction and the multi-mover 36 is arranged closer to the X1 direction with respect to the center 21C of the spin base 21.
The single mover 35 includes a fixed base 351, a rotary motor 352, a power transmitter 353, and a slider 354. The rotary motor 352 is mounted on the fixed base 351, and the power transmitter 353 and the slider 354 are stacked in this order over the fixed base 351. The rotary motor 352 is a driving source for moving the contact member 31 in the X direction. When the rotary motor 352 operates in response to a control command from the control unit 9, a rotary shaft (not shown in the drawings) rotates. This rotary shaft extends from the top of the fixed base 351 to the power transmitter 353 and rotary driving force generated by the rotary motor 352 is transmitted to the power transmitter 353. Using a rack-and-pinion structure, for example, the power transmitter 353 converts rotary motion responsive to the rotary driving force to liner motion in the X direction, and transmits the linear motion to the slider 354. This makes the slider 354 move back and forth in the X direction by a distance responsive to the amount of the rotation. As a result, in response to the movement of the slider 354, the contact member 31 mounted on the top of the slider 354 is moved in the X direction.
The multi-mover 36 has a configuration basically the same as that of the single mover 35 except that a slider 364 has a partially different structure. Specifically, the multi-mover 36 applies rotary driving force generated by a rotary motor 362 mounted on a fixed base 361 to the slider 364 using a power transmitter 363, thereby moving the slider 364 in the X direction. The slider 364 has a top including two arms 364a and 364b extending in the X2 direction and separated from each other in a Y direction. The top of the slider 364 has a substantially C-shape in a plan view from vertically above. The contact members 32 and 33 are mounted on end portions closer to the X2 direction of the arms 364a and 364b respectively. Thus, when the rotary motor 362 operates in response to a control command from the control unit 9, the slider 364 moves back and forth in the X direction by a distance responsive to the amount of the rotation of the rotary motor 362, like in the single mover 35. As a result, in response to the movement of the slider 364, the contact members 32 and 33 mounted on the slider 364 are moved in the X direction.
The contact members 31 to 33 have contact surfaces 311 to 331 capable of contacting the end face Se of the substrate S, respectively. With these contact surfaces 311 to 331 directed toward the end face Se of the substrate S, the contact members 31 to 33 are arranged so as to surround the substrate holder 2 in the XY plane (horizontal plane). The contact surfaces 311 to 331 have a planar shape, and their surface normals face the vertical axis AX. For example, as shown in section (a) of
When the contact member 31 is moved in the X1 direction by the single mover 35, a contact surface 311 of the contact member 31 goes toward the center 21C of the spin base 21 to contact on the end face Se of the substrate S. As described above, in the present embodiment, a D1 direction in which the contact member 31 moves for abutting on the substrate S is the X1 direction, and this direction corresponds to a “first horizontal direction” of the present invention. After making the abutting contact, the contact member 31 moves further in the D1 direction, thereby moving the substrate S horizontally on the upper surface 211 of the spin base 21 in the X1 direction while pressing the substrate S in the X1 direction. In the present embodiment, to facilitate understanding of the substance of the invention, a virtual line VL extended in the X1 direction from the center 21C of the spin base 21 is additionally illustrated in
A configuration in which the contact members 32 and 33 are moved by the multi-mover 36 partially differs from that of the contact member 31. The reason for this is that the contact members 32 and 33 are arranged line-symmetrically to each other with respect to the virtual line VL in the horizontal plane and are moved in the X direction while being kept in this arrangement state. More specifically, as shown in a section (a) of
To place the substrate S on the upper surface 211 of the spin base 21, the contact surfaces 311, 321 and 331 are desirably positioned at reference positions at least in consideration of a maximum value of an outer diameter tolerance of the substrate S. For example, in the substrate S having a diameter of 300 mm, the outer diameter tolerance is 0.2 mm. Accordingly, the contact surfaces 311, 321 and 331 need to be separated from the center 21C of the spin base 21 by a distance of 150.1 mm or more. This distance is referred to as a “reference distance r0” in this embodiment and, as shown in field (a) of
Next, a case is studied where the contact surfaces 311, 321 and 331 are moved toward the substrate S after the contact members 31 to 33 are so positioned that the contact surfaces 311, 321 and 331 are located on the reference circle. In this case, the position of the contact member 31 for positioning the contact surface 311 on the reference circle corresponds to a “first reference position” of the invention, the position of the contact member 32 for positioning the contact surface 321 on the reference circle corresponds to a “second reference position” of the invention, and the position of the contact member 33 for positioning the contact surface 331 on the reference circle corresponds to a “third reference position” of the invention.
Here, a case is studied next, where the contact members 31 to 33 are located at the first reference position, the second reference position, and the third reference position respectively, the contact member 31 makes a tiny movement by a first movement amount Δd1 in the D1 direction (X1 direction) toward the substrate S. If each of the contact members 32 and 33 makes a tiny movement by the same distance in the D2 direction (X2 direction) in response to the movement of the contact member 31, the contact surfaces 311, 321, and 331 are separated by nonuniform distances from the center 21C of the spin base 21. Hence, repeating the tiny movements of the contact members 31 to 33 while keeping a uniform movement amount per unit time results in the failure to align the center SC of the substrate S with the center 21C of the spin base 21.
In contrast, as shown in field (b) of
As shown in
Thus, a fine moving distance Δd2 (corresponding to a “second movement amount” of the invention) of the contact member 32 and a fine moving distance Δd3 (corresponding to a “third movement amount” of the invention) of the contact member 33 can be set as follows:
In the present embodiment including the centering mechanism 3, the control unit 9 controls each part of the substrate processing apparatus 10 to perform the centering operation described above and the subsequent bevel etching process. The control unit 9 includes an arithmetic processor 91 composed of a computer with a central processing unit (CPU), a random access memory (RAM), etc., a storage 92 such as a hard disk drive, and a motor controller 93.
The arithmetic processor 91 reads a centering program and a bevel etching program as appropriate stored in advance in the storage 92, develops the program in the RAM (not shown in the drawings), and performs the centering operation and the bevel etching process shown in
As described above, in the present embodiment, the contact members 31 to 33 make the tiny movements repeatedly to get closer to the substrate S gradually while distances from the center 21C of the spin base 21 to the contact surfaces 311, 321, and 331 are kept equally. Then, the substrate S is nipped with the three contact members 31 to 33 to align the center SC of the substrate S with the center 21C of the spin base 21. As described above, the centering operation is performed only through the tiny movements of the contact members 31 to 33 made repeatedly. This achieves implementation of the centering operation with excellent throughput (effect A).
The completion of the centering operation is determined on the basis of variation in the load torque and the movements of the contact members 31 to 33 are stopped immediately. This makes it possible to finish the centering operation at appropriate time without damaging the substrate S (effect B). This also applies to embodiments described later.
Further, since the contact members 31 to 33 have linear regions 312, 322 and 332 formed to intersect an XY plane as shown in field (a) of
However, for example, in a comparative example shown in field (b) of
In contrast, in this embodiment, the contact surfaces 311 to 331 of the contact members 31 to 33 have a flat surface shape. Thus, as shown in field (a) of
Here, when an eccentricity amount and an eccentricity direction were measured while a rotation amount of the substrate (semiconductor wafer having a radius of 150 mm) placed on the spin base 21 about the vertical axis AX was switched by 0.25° in a range of 326.25° to 329.75° in the centering mechanism 3 shown in
A combination of the centering mechanism 3 and the control unit 9 corresponds to the first embodiment of the centering device according to the invention, but the configurations of the contact surfaces 311, 321 and 331 in the centering mechanism 3 are not limited to this. For example, the contact surfaces 311, 321 and 331 may be finished such that contactable regions intersecting the XY plane are curved as shown in
As shown in field (a) of
Here, if an eccentric deviation amount by the notch NT (angle of 1.119°) provided in the substrate S (semiconductor wafer having a radius of 150 mm) was obtained while the radius of curvature was changed in multiple stages, an experimental result shown in
As described above, in the substrate processing apparatus 10, a combination of the centering mechanism 3 and the control unit 9 corresponds to the first embodiment of the centering device according to the present invention. Specifically, the contact members 31 to 33 correspond to an example of a “first contact member,” an example of a “second contact member,” and an example of a “third contact member” of the present invention respectively.
The control unit 9 corresponds to an example of a “controller” of the present invention. The spin base 21 and the center 21C correspond to an example of a “substrate support” and an example of the “center of the substrate support” of the present invention respectively. The suction pump 24 corresponds to an example of a “suction unit” of the present invention.
In the first embodiment described above, the two contact members 32 and 33 are moved in the D2 direction (X2 direction) and in the D3 direction (X2 direction) respectively by the multi-mover 36. However, the multi-mover 36 may be replaced with a single mover for the contact member 32 and a single mover for the contact member 33 each having the same configuration as the single mover 35. In this case, the single movers provided for the contact members 31 to 33 correspond to an example of a “first single mover,” an example of a “second single mover,” and an example of a “third single mover” of the present invention respectively.
Like in this case, if the single mover for the contact member 32 and the single mover for the contact member 33 are provided, both the D2 direction and the D3 direction are not required to conform to the X2 direction but at least one of the D2 direction and the D3 direction may be changed from the X2 direction (second embodiment).
Also in the third embodiment having the above-described configuration, the contact members 31 to 33 successively abut on the substrate S so the substrate S is nipped with the contact members 31 to 33 while distances from the center 21C of the spin base 21 to the contact surfaces 311, 321, and 331 are kept equally. By doing so, the center SC of the substrate S is aligned with the center 21C of the spin base 21. In this way, the centering operation is performed only through tiny movements of the contact members 31 to 33 made repeatedly to achieve implementation of the centering operation with excellent throughput.
Note that the invention is not limited to the above embodiments and various changes other than the aforementioned ones can be made without departing from the gist of the invention. For example, in the above-described embodiments, nipping the substrate S with the contact members 31 to 33, namely, completion of the centering operation is detected on the basis of variation in a load torque. The detection may be made by another method. In an exemplary configuration, the single mover 35 or 38 or the multi-mover 36 may be provided with a sensor such as a load cell or a strain gauge, and stress or strain may be detected by the sensor when the substrate S is nipped with the contact members 31 to 33 to output a detection signal. In this case, the control unit 9 determines nipping the substrate S with the contact members 31 to 33 on the basis of the detection signal from the sensor.
In the above-described embodiments, the present invention is applied to the centering device provided to the substrate processing apparatus 10 that performs the bevel etching process. Meanwhile, the centering device according to the present invention is applicable to every type of centering device provided to a substrate processing techniques that performs a process while rotating a substrate of a circular plate shape and to and every type of centering method. Also, the centering device according to the present invention may be used alone.
Further, although the substrate is centered using the three contact members in the above embodiments, the invention can be applied to a centering device using four or more contact members.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as other embodiments of the present invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.
This invention can be applied to a centering technique for horizontally moving and positioning a substrate such that a center of the substrate is aligned with a center of a substrate support with the disk-like substrate provided with a cut such as a notch placed in a horizontal posture on the upper surface of the substrate support, and substrate processing apparatuses in general for processing a substrate utilizing the centering technique.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-119717 | Jul 2022 | JP | national |
