System and method for contactless handling of semiconductor wafers

Abstract

This disclosure relates to a system (100) and a method (400) for non-contact handling of a semiconductor wafer (200). The system (100) comprises a wafer table (300) that supports a semiconductor wafer (200) without physical contact and has a fluid outlet for exhausting gas; an air pipe (140) that supplies gas to the fluid outlet; and an air controller (150) that controls the gas flow in the air pipe (140) and thereby selectively exhausts gas from the fluid outlet. A first set of fluid outlets exhausts gas so that the exhausted gas supports the semiconductor wafer (200) non-contact with the wafer table (300). A second set of fluid outlets exhausts gas so that the exhausted gas rotates the semiconductor wafer (200) while the semiconductor wafer (200) is non-contact supported by the wafer table (300). The air controller (150) controls the discharge of gas from the first and second sets of fluid outlets, thereby controlling the support and rotation of the semiconductor wafer (200).

Description

Cross - reference to related applications

[0001] This specification claims priority to Singapore Patent Application No. 10202300962, filed on April 6, 2023, the entire content of which is incorporated herein by reference.

Technical Field

[0002] This disclosure relates to the non - contact handling of semiconductor wafers. More specifically, this disclosure describes various embodiments of systems and methods for the non - contact handling of semiconductor wafers using gas.

Background Art

[0003] In semiconductor wafer processing steps, various types of processing steps and a series of treatments are performed on semiconductor wafers. In a wide variety of semiconductor device processing steps, multiple handling systems are involved in the wafer handling operation of safely and selectively transporting semiconductor wafers from one place to another. In particular, the handling system has to take out the semiconductor wafer from the wafer cassette and transfer it to another station such as another wafer cassette or a wafer table.

[0004] For example, the handling system transfers the semiconductor wafer from the wafer cassette to the wafer table. The wafer table securely holds the semiconductor wafer before semiconductor processes such as inspection and releases the wafer after the semiconductor process is completed. To fix the semiconductor wafer to the surface of the wafer table, usually, vacuum suction, gentle holding on the end effector, or edge grip is used. Therefore, the flatness of the wafer table surface is important to securely hold the semiconductor wafer on the wafer table surface. In the case of very thin semiconductor wafers, it is important that the wafer table is ultra - flat, otherwise one or more dies on the semiconductor wafer are likely to be out of the depth of focus during inspection.

[0005] In addition to ensuring the flatness of the wafer table surface, it is crucial to ensure that no particulate matter is present that could affect the retention of semiconductor wafers on the table surface. The presence of particulate matter such as dust can prevent semiconductor wafers from being properly and uniformly placed on the table surface. This dust can contaminate the table surface and subsequently contaminate the semiconductor wafers placed on the wafer table surface, leading to yield and reliability problems.

[0006] Furthermore, because semiconductor wafers come in various shapes and sizes, handling systems are configured to align the semiconductor wafers when transporting them to another location. This alignment process may involve rotating the semiconductor wafer during transport. One known alignment device for rotating semiconductor wafers is a pre-aligner, which secures the wafer to a chuck using edge gripping, vacuum chucking, or electrostatic chucking. Alignment is then possible by rotating the wafer on the chuck. [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem with existing handling systems is that semiconductor wafers must be in physical contact with a wafer table to be secured by vacuum chucks or edge grips. Another problem is that alignment devices must be in physical contact with the semiconductor wafers to rotate and align them. This increases the risk of contamination and damage to the semiconductor wafers, leading to yield and quality problems. For example, physical contact can cause unwanted dust particles to adhere to the wafer surface or microscopic cracks to form within the wafer material.

[0008] Therefore, in order to address or mitigate at least one of the aforementioned problems and / or drawbacks, there is a need to provide improved systems and methods for handling semiconductor wafers. [Means for solving the problem]

[0009] According to a first aspect of this disclosure, a system for contactless handling of semiconductor wafers is provided. This system is A wafer table configured to support semiconductor wafers without physical contact and including multiple fluid outlets configured to discharge gases, A plurality of air pipes, which are fluidically connected to the fluid outlet in order to supply gas to the fluid outlet, The system includes an air controller configured to control the gas flow within the air piping and thereby selectively discharge gas from the fluid outlet, The first set of fluid outlets is configured to discharge gas flowing from the air piping, thereby supporting the semiconductor wafer against the wafer table without causing physical contact between the semiconductor wafer and the wafer table. The second set of fluid outlets is configured to discharge gas flowing from the air piping, thereby causing the gas discharged from the second set of fluid outlets to rotate the semiconductor wafer while the semiconductor wafer is supported by the wafer table without physical contact. The air controller is configured to control the discharge of gas from the first and second sets of fluid outlets, thereby controlling the support and rotation of the semiconductor wafer.

[0010] According to a second aspect of this disclosure, a method for contactless handling of semiconductor wafers is provided. This method is A step of aligning a semiconductor wafer and a wafer table relative to each other, wherein the wafer table includes a plurality of fluid outlets configured to discharge gases, The steps include using an air controller to control the gas flow in multiple air pipes fluidly connected to the fluid outlet, thereby selectively discharging gas from the fluid outlet, The steps include: discharging gas flowing from the air piping from the first set of fluid outlets, thereby supporting the semiconductor wafer against the wafer table without the gas discharged from the first set of fluid outlets causing physical contact between the semiconductor wafer and the wafer table; The steps include: discharging gas flowing from the air piping from a second set of fluid outlets, thereby causing the gas discharged from the second set of fluid outlets to rotate the semiconductor wafer while the semiconductor wafer is supported by the wafer table without physical contact; The method includes the step of using the air controller to control the discharge of gas from the first and second sets of fluid outlets, thereby controlling the support and rotation of the semiconductor wafer.

[0011] A system and method for contactless handling of semiconductor wafers are disclosed herein. Various features and advantages of this disclosure will become more apparent from the following detailed description of embodiments of this disclosure, along with the accompanying drawings, only as non-limiting examples. [Brief explanation of the drawing]

[0012] [Figure 1A] This is a diagram of a system for contactless handling of semiconductor wafers according to an embodiment of the present disclosure. [Figure 1B] This is a diagram of a system for contactless handling of semiconductor wafers according to an embodiment of the present disclosure. [Figure 1C] This is a diagram of a system for contactless handling of semiconductor wafers according to an embodiment of the present disclosure. [Figure 2A] This is a diagram of the wafer table for the system in question. [Figure 2B] This is a diagram of the wafer table for the system in question. [Figure 3A] Figures 2A and 2B show semiconductor wafers floating above the wafer table. [Figure 3B]It is a view of a semiconductor wafer floating above the wafer tables of FIGS. 2A and 2B. [Figure 4] It is a flowchart diagram of a method for non-contact handling of a semiconductor wafer according to an embodiment of the present disclosure. [Figure 5A] It is a view showing another wafer table of the system. [Figure 5B] It is a view showing another wafer table of the system. [Figure 5C] It is a view showing another wafer table of the system. [Figure 5D] It is a view showing another wafer table of the system. [Figure 6A] It is a view of a semiconductor wafer gripped below the wafer tables of FIGS. 5A to 5D. [Figure 6B] It is a view of a semiconductor wafer gripped below the wafer tables of FIGS. 5A to 5D.

Mode for Carrying Out the Invention

[0013] For the purposes of brevity and clarity, the description of the embodiments of the present disclosure focuses on systems and methods for non-contact handling of semiconductor wafers based on the drawings. It should be understood that although some parts of the present disclosure are described in combination with the embodiments provided herein, they are not intended to limit the present disclosure to these embodiments. Rather, the present disclosure is intended to include alternatives, modifications, and equivalents to the embodiments described herein that are within the scope defined by the appended claims. Further, in the following detailed description, specific details are set forth in order to provide a thorough understanding of the present disclosure. However, those of ordinary skill in the art, i.e., those skilled in the art, will recognize that the present disclosure can be implemented without specific details and / or with multiple details resulting from combinations of the features of specific embodiments. In many cases, well-known systems, methods, procedures, and components are not described in detail so as not to unnecessarily obscure the features of the embodiments of the present disclosure.

[0014] In embodiments of the present disclosure, the depiction of a given element or consideration in a particular drawing, or the use of a particular element number, or reference thereto in the corresponding description, can include the same element, equivalent element, or similar element or element number specified in other drawings or related descriptions.

[0015] Expressions such as "one embodiment / example", "another embodiment / example", "some embodiments / examples", "some other embodiments / examples", etc. indicate that the embodiments / examples so described may include certain functions, structures, characteristics, properties, elements, or limitations, but not all embodiments / examples necessarily include those specific functions, structures, characteristics, properties, elements, or limitations. Further, repeated use of the expressions "in one embodiment / example" or "in another embodiment / example" does not necessarily refer to the same embodiment / example.

[0016] Terms such as "include", "comprise", "have", etc. do not exclude the presence of features / elements / steps other than those described in the examples. The fact that a particular feature / element / step is described in different examples does not indicate that a combination of these features / elements / steps cannot be used in the examples. In this specification, the terms "one" and "one or more" mean one or more. The use of " / " in the drawings or related text is understood to mean "and / or" unless otherwise specified. The term "set" is defined according to the known mathematical definition as a non-empty finite organization of elements, indicating a mathematical cardinality of at least one (for example, in this definition, a set can correspond to a singleton set, a single-element set, or a multi-element set). Terms such as "first", "second", etc. are used merely as labels or identifiers and are not intended to impose numerical requirements on related terms.

[0017] A representative or exemplary embodiment of the present disclosure describes a system 100 for non-contact handling of a substrate with reference to Figures 1A to 1C. The term “substrate” as used herein may include semiconductor wafers, partial wafers, or film frames on which wafers or parts thereof are mounted. The term “wafer” as used herein may include whole wafers, partial wafers, or other types of whole or partial objects or components (e.g., solar cells).

[0018] In many embodiments, system 100 is configured for non-contact handling of semiconductor wafers 200. System 100 includes a wafer table 300 configured to transport the semiconductor wafers 200 without physical contact. This is achieved, in particular, by utilizing gas exhaust as described later. Furthermore, as used herein, the term “wafer table” also includes devices for holding semiconductor wafers 200 or film frames during semiconductor processes (e.g., wafer inspection processes or film frame inspection processes).

[0019] In one embodiment, the system 100 includes an arm mechanism 110 connected to a wafer table 300 and configured to move the wafer table 300, on which semiconductor wafers 200 are placed, from a first station 120 to a second station 130. In particular, the wafer table 300 is configured to transport the semiconductor wafers 200 non-contact during the move from the first station 120 to the second station 130. The stations 120, 130 can be located at any suitable position within a semiconductor process designed to perform various semiconductor operations and processes. For example, the first station 120 may be a wafer cassette that houses a stack of semiconductor wafers 200. The second station 130 may be another wafer cassette that receives a stack of semiconductor wafers 200. Alternatively, the second station 130 may be an inspection station that inspects the semiconductor wafers 200. In yet another example, the second station 130 may be a process chamber or a standby station. It will be understood that the first station 120 and the second station 130 can be any station in the semiconductor process.

[0020] The arm mechanism 110 may include a set of one or more robotic arms 112 configured to move the wafer table 300 in up to three mutually orthogonal directions, i.e., the x, y, and z directions. The wafer table 300 is configured to support a semiconductor wafer 200 during its movement from a first station 120 to a second station 130. In particular, as shown in Figure 1B, the arm mechanism 110 and the wafer table 300 pick up the semiconductor wafer 200 from the first station 120, support the semiconductor wafer on the wafer table 200 without the semiconductor wafer 200 physically contacting the surface of the wafer table 200, and move the semiconductor wafer 200 to the second station 130 non-contact. The wafer table 300 securely holds the semiconductor wafer 200 picked up from the first station 120 and releases the semiconductor wafer 200 at the second station 130.

[0021] In one embodiment, the system 100 does not include an arm mechanism 110. For example, the wafer table 300 is positioned on a fixed chuck and is configured to transport the semiconductor wafer 200 without physical contact with the semiconductor wafer 200.

[0022] As described above, the wafer table 300 is configured to transport semiconductor wafers 200 non-contact using gas discharge. The wafer table 300 has multiple fluid outlets, such as the fluid channels 310 shown in Figures 2A and 2B. The system 100 includes multiple air pipes 140 that are fluidically connected to the fluid outlets to supply gas to the fluid outlets. For example, the fluid outlets are fluid channels configured to discharge the gas flowing from the air pipes 140 through the longitudinal shape of the fluid channels. The gas flowing in the air pipes 140 may include any suitable gas, such as air (e.g., clean dry air) or nitrogen. Furthermore, the gas should be supplied from a clean gas source so as not to contaminate the semiconductor wafers 200.

[0023] The system 100 further includes an air controller 150 configured to control the flow of gas in the air piping 140, thereby selectively discharging gas from the fluid outlet. The system 100 may also include appropriate fluid components 160, such as pumps and valves, connected to the air piping 140 and the air controller 150, to supply gas and regulate the gas flow rate in the air piping 140.

[0024] The first set of fluid outlets is configured to discharge gas from the air piping 140. This allows the gas discharged from the first set of fluid outlets to support the semiconductor wafer 200 against the wafer table 300. No physical contact occurs between the two. For example, the first set of fluid outlets includes a first fluid channel 310a. Figures 3A and 3B show the semiconductor wafer 200 floating above the surface of the wafer table 300 with a spatial gap 320.

[0025] A second set of fluid outlets is configured to discharge gas from the air piping 140. This causes the gas discharged from the second set of fluid outlets to rotate the semiconductor wafer 200. During this time, the semiconductor wafer 200 is supported by the wafer table 300, and there is no physical contact between the two. For example, the second set of fluid outlets includes a second fluid channel 310b. The air controller 150 is configured to control the discharge of gas from the first and second sets of fluid outlets, namely the first fluid channel 310a and the second fluid channel 310b, thereby controlling the support and rotation of the semiconductor wafer 200.

[0026] The embodiments of this disclosure also describe a method 400 for handling a substrate such as a semiconductor wafer 200 in a non-contact manner, with reference to Figure 4.

[0027] Method 400 includes step 410 of aligning a semiconductor wafer 200 and a wafer table 300 relative to each other. The wafer table 300 has a plurality of fluid outlets configured to discharge gas. Method 400 includes step 420 of using an air controller 150 to control the flow of gas in a plurality of air pipes 140 that are fluidly connected to the fluid outlets, thereby selectively discharging gas from the fluid outlets. Method 400 includes step 430 of discharging gas flowing from the air pipes 140 from a first set of fluid outlets. This causes the gas discharged from the first set of fluid outlets to support the semiconductor wafer 200 against the wafer table 300 without causing physical contact between them. Method 400 includes step 440 of discharging gas flowing from the air pipes 140 from a second set of fluid outlets. This causes the gas discharged from the second set of fluid outlets to rotate the semiconductor wafer 200 while the semiconductor wafer 200 is supported by the wafer table 300 without physical contact. Method 400 includes step 450 of controlling gas discharge from first and second sets of fluid outlets using an air controller 150. This controls the support and rotation of the semiconductor wafer 200.

[0028] As shown in Figure 2B, in one embodiment, the first set of fluid outlets includes a first fluid channel 310a, and the second set of fluid outlets includes a second fluid channel 310b. The first fluid channel 310a has a shape that allows the exhaust gas to levitate the semiconductor wafer 200 above the wafer table 300, as shown in Figures 3A and 3B. The second fluid channel 310b has a shape that rotates the semiconductor wafer 200, which is levitating above the wafer table 300, with the exhaust gas.

[0029] For example, the first fluid channel 310a includes one or more linear fluid channels. The linear fluid channels may extend radially outward from the center of the wafer table 300. The linear fluid channels may be arranged at equal intervals around the center of the wafer table 300. Alternatively, the first fluid channel 310a may include one or more circular channels concentric with the center of the wafer table 300.

[0030] For example, the second fluid channel 310b may include one or more bendable fluid channels. The bendable fluid channels have a bending angle and may take the form of a curved or curved channel. For example, the bendable fluid channels may include straight sections that are bent at angles to each other. For example, the bendable fluid channels may include both curved and straight sections.

[0031] More specifically, the second fluid channel 310b is bent toward the desired rotational direction, i.e., clockwise or counterclockwise. For example, as shown in Figure 2B, the second fluid channel 310b includes a curved channel that is convexly curved toward the counterclockwise rotational direction. The curvature of the second fluid channel 310b allows the exhaust gas to maintain a floating state above the wafer table 300 while rotating the semiconductor wafer 200 counterclockwise. It will be understood that if the second fluid channel 310b is bent toward the clockwise rotational direction, the semiconductor wafer 200 may rotate clockwise.

[0032] The wafer table 300 may include an additional set of fluid outlets, in addition to the first and second sets of fluid outlets, to assist in supporting and / or rotating the semiconductor wafer 200. For example, the second fluid channel 310b is bent to rotate the semiconductor wafer 200 clockwise. The wafer table 300 may also include a third set of fluid outlets, for example, a third fluid channel bent in a different direction to rotate the semiconductor wafer 200 counterclockwise. Different sets of fluid outlets, such as different sets of bent fluid channels, may also be provided to vary the rotational speed of the semiconductor wafer 200. For example, the second fluid channel 310b can rotate the semiconductor wafer 200 clockwise at a constant speed, while the third fluid channel can rotate the semiconductor wafer 200 clockwise at a higher speed. The second and third fluid channels may complement each other to increase the rotational speed of the semiconductor wafer 200.

[0033] As described above, system 100 includes an air pipe 140 that is fluidly connected to a fluid outlet. For example, the air pipe 140 includes a first air pipe that is fluidly connected to a first fluid channel 310a in the wafer table 300. The first fluid channel 310a is configured to discharge gas flowing from the first air pipe. The first fluid channel 310a has a shape that allows the discharged gas to levitate the semiconductor wafer 200 above the wafer table 300. For example, the first fluid channel 310a has a linear shape and consists of linear fluid channels evenly distributed on the wafer table 300. The gas discharged from the first fluid channel 310a pushes the semiconductor wafer 200 upward and levitates it above the surface of the wafer table 300, as shown in Figures 3A and 3B.

[0034] The air piping 140 may include a second air piping fluidly connected to a second fluid channel 310b in the wafer table 300. The second fluid channel 310b is configured to discharge gas flowing from the second air piping. The second fluid channel 310b has a shape that allows the discharged gas to rotate the semiconductor wafer 200 while it is suspended above the wafer table 300. For example, the second fluid channel 310b has a bent shape and is composed of a bent fluid channel. The gas discharged from the second fluid channel 310b pushes the suspended semiconductor wafer clockwise or counterclockwise, thereby rotating the semiconductor wafer that is suspended on the surface of the wafer table 300.

[0035] In one example shown in Figure 2B, the first fluid channel 310a includes six straight fluid channels evenly distributed on the wafer table 300, and the second fluid channel 310b includes six curved fluid channels evenly distributed on the wafer table 300. The second fluid channels 310b are curved or bent at an angle to allow the exhaust gas to rotate the semiconductor wafer 200. More specifically, each second fluid channel 310b is convex in the counterclockwise direction, thereby causing the exhaust gas to rotate the semiconductor wafer 200 counterclockwise. The curved or bent shape of the second fluid channels 310b causes the exhaust gas to act on the semiconductor wafer 200 at an angle, resulting in its rotation. The rotation speed can be adjusted by changing this curved or bent shape and angle. For example, by bending the second fluid channels 310b more convexly and at a sharper angle, the rotation speed can be increased at the same gas flow rate in the second air piping.

[0036] It will be understood that the flow rate of the gas circulating through the air piping 140 for suspending / rotating the semiconductor wafer 200 and discharged from the fluid outlet may vary depending on the intended end use of the wafer table 300. For example, the flow rate may be in the range of 10 L / min to 200 L / min, but is not limited to this range.

[0037] In one embodiment, the air piping 140 includes a third air piping configured to brake the rotation of the semiconductor wafer 200, which is fluidly connected to the wafer table 300. For example, the third air piping discharges gas to activate a braking device and stop the rotation.

[0038] As described above, the air controller 150 is configured to control the discharge of gas from the fluid outlet, thereby controlling the support and rotation of the semiconductor wafer 200. The controlled rotation makes it possible to rotate the semiconductor wafer 200 for various semiconductor processing steps. For example, the controlled rotation makes it possible to position the semiconductor wafer 200, such as aligning it to a second station 130. For example, the air controller 150 controls fluid components 160 such as pumps and valves, thereby adjusting the gas flow rate in the air piping 140. For example, the air controller controls the flow rate of gas discharged from the first fluid channel 310a, thereby controlling the floating state of the semiconductor wafer 200. Specifically, it controls the size of the spatial gap 320 between the semiconductor wafer 200 and the surface of the wafer table 300. For example, the air controller 150 controls the flow rate of gas discharged from the second fluid channel 310b, thereby controlling the rotation of the floating semiconductor wafer 200. Increasing the gas flow rate increases the gas discharge speed and thus the rotation speed.

[0039] In one embodiment, the system 100 may include a set of one or more alignment sensors for controlling the alignment of the semiconductor wafer 200. Specifically, the alignment sensors are configured to detect alignment elements of the semiconductor wafer 200. The air controller 150 may be configured to stop the rotation of the semiconductor wafer 200 in response to the alignment sensors detecting alignment elements. For example, the air controller 150 stops the gas flow in an air pipe (e.g., a second air pipe) to stop the rotation of the semiconductor wafer 200. The alignment sensors may include optical sensors.

[0040] The system 100 may further include a set of auxiliary sensors that cooperate with the alignment sensor to control the alignment of the semiconductor wafer 200. Specifically, the auxiliary sensors are configured to detect alignment elements on the semiconductor wafer 200 before the alignment sensor detects the alignment elements. The air controller 150 may be configured to slow down the rotation of the semiconductor wafer 200 in response to the auxiliary sensors detecting the alignment elements. For example, the air controller 150 slows down the rotation of the semiconductor wafer 200 by adjusting the gas flow rate in the air piping (e.g., a second air piping). The auxiliary sensors may include optical sensors.

[0041] As an example, the alignment element of the semiconductor wafer 200 includes a notch on the edge of the semiconductor wafer 200. As the semiconductor wafer rotates, a preliminary sensor detects the notch, and the air controller 150 reduces the gas flow rate in the second air pipe, thereby reducing gas discharge from the second fluid channel 310b and slowing down the rotation of the semiconductor wafer 200. The semiconductor wafer 200 continues to rotate slowly until the alignment sensor detects the notch. When the alignment sensor detects the notch, the air controller 150 stops the gas flow in the second air pipe, thereby stopping gas discharge from the second fluid channel 310b and stopping the rotation of the semiconductor wafer 200. The slow rotation of the semiconductor wafer 200 from detection by the preliminary sensor to detection by the alignment sensor allows the notch to be more accurately aligned with the alignment sensor. This ensures that the semiconductor wafer 200 is accurately aligned with the second station 130.

[0042] For example, system 100 does not have a backup sensor. The air controller 150 controls the gas flow rate in the second air pipe to cause the semiconductor wafer 200 to rotate at a relatively low speed. The semiconductor wafer 200 continues to rotate at a low speed until the alignment sensor detects a notch. When the alignment sensor detects a notch, the air controller 150 stops the gas flow in the second air pipe and stops the rotation of the semiconductor wafer 200.

[0043] As an example, the alignment element of the semiconductor wafer 200 includes a straight edge on the semiconductor wafer. As the semiconductor wafer 200 rotates, a preliminary sensor detects the straight edge, and the air controller 150 reduces the gas flow rate in the second air pipe, thereby slowing down the rotation of the semiconductor wafer 200. For example, the preliminary sensor may include a pair of sensors arranged to detect the straight edge. The semiconductor wafer 200 continues to rotate slowly until the alignment sensor detects the straight edge. Once the alignment sensor detects the straight edge, the air controller 150 stops the gas flow in the second air pipe, stopping the rotation of the semiconductor wafer 200. For example, the alignment sensor may include a pair of sensors arranged to detect the straight edge.

[0044] For example, system 100 does not have a backup sensor. The air controller 150 controls the gas flow rate in the second air pipe so that the semiconductor wafer 200 rotates at a relatively low speed. The semiconductor wafer 200 continues to rotate at a low speed until the alignment sensor detects a straight edge. When the alignment sensor detects a straight edge, the air controller 150 stops the gas flow in the second air pipe, thereby stopping the rotation of the semiconductor wafer 200.

[0045] An embodiment of method 400 performed using system 100 is described below. System 100 includes an arm mechanism 110 for moving a wafer table 300. 1. The wafer table 300 is moved to the first station 120 using the arm mechanism 110 and the semiconductor wafer 200 is received. The arm mechanism 110 includes a robotic arm 112 programmed to align with the first station 120 (in the x, y, and z directions) and lift the semiconductor wafer 200. 2. At the first station 120, a wafer table 300 is positioned below the semiconductor wafer 200. For example, the first station 120 is a wafer cassette, and an arm mechanism 110 (such as programming of a robot arm 112) is used to position the wafer table 300 below a wafer unit or slot in the wafer cassette 120. In particular, the wafer table 300 does not physically contact the semiconductor wafer 200 at any point. For example, the wafer table 300 may be equipped with guide elements or pins to assist in the alignment of the semiconductor wafer 200, but these guide elements or pins do not physically contact the semiconductor wafer 200. 3. Gas is discharged from the first air piping to the first fluid channel 310a in the wafer table 300. 4. The semiconductor wafer 200 is suspended above the wafer table 300 using the gas discharged from the first fluid channel 310a. 5. The semiconductor wafer 200 is transported using the wafer table 300 without physical contact. 6. The arm mechanism 110 is used to move the wafer table 300, on which the semiconductor wafer 200 is placed, toward the second station 130. For example, the robot arm 112 is programmed to align itself with the second station (in the x, y, and z directions) and transport the semiconductor wafer 200. 7. Gas is discharged from the second air pipe into the second fluid channel 310b within the wafer table 300. 8. Using the gas discharged from the second fluid channel 310b, the semiconductor wafer 200 is rotated while suspended above the surface of the wafer table 300. 9. The gas flow rate in the air piping 140 is controlled to control the rotation of the semiconductor wafer 200. 10. The controlled rotation of the semiconductor wafer 200 aligns the semiconductor wafer 200 with respect to the second station 130. 11. During the alignment of the auxiliary sensor, the gas flow rate in the second air pipe is arbitrarily reduced to slow down the rotation of the semiconductor wafer 200. 12. When the alignment sensor is being aligned, the gas flow in the second air pipe is stopped, and the rotation of the semiconductor wafer 200 is stopped. 13. The wafer table 300 is placed in the second station 130. For example, the second station 130 is another wafer cassette, and the wafer table 300 is placed below the wafer receiving unit or slot in the wafer cassette using the arm mechanism 110, through programming of the robot arm 112, etc. 14. The gas flow in the first air piping is stopped, preventing the semiconductor wafer 200 from floating, and causing the semiconductor wafer 200 to fall into the wafer receiver. In particular, since the surface of the wafer table 300 is slightly lower than the wafer receiver, the semiconductor wafer 200 does not physically come into contact with the wafer table 300 even when it falls.

[0046] Another embodiment of method 400, which is carried out using system 100, is described below. System 100 does not include an arm mechanism 110, and the wafer table 300 is placed on a fixed chuck. 1. A wafer table 300 is placed below the semiconductor wafer 200. The wafer table 300 may have guide elements or pins to assist in the alignment of the semiconductor wafer 200, but these guide elements or pins do not physically contact the semiconductor wafer 200. 2. Gas is discharged from the first air piping to the first fluid channel 310a in the wafer table 300. 3. The semiconductor wafer 200 is suspended above the wafer table 300 using the gas discharged from the first fluid channel 310a. 4. The semiconductor wafer 200 is transported using the wafer table 300 without physical contact. 5. Gas is discharged from the second air piping to the second fluid channel 310b in the wafer table 300. 6. The semiconductor wafer 200 is rotated while suspended above the surface of the wafer table 300 using the gas discharged from the second fluid channel 310b. The fixed chuck may include a rotational speed sensor or RPM sensor for measuring the rotational speed of the semiconductor wafer 200. 7. The gas flow rate in the air piping 140 is controlled to control the rotation of the semiconductor wafer 200. 8. The controlled rotation of the semiconductor wafer 200 aligns the semiconductor wafer 200 with respect to the second station 130. 9. During the alignment of the auxiliary sensor, the gas flow rate in the second air pipe is arbitrarily reduced to slow down the rotation of the semiconductor wafer 200. 10. When the alignment sensor is being aligned, the gas flow in the second air pipe is stopped, and the rotation of the semiconductor wafer 200 is stopped.

[0047] In one embodiment, the wafer table 300 of system 100 is replaceable with another wafer table 500 which has a similar configuration for gas evacuation for supporting and rotating semiconductor wafers 200.

[0048] As shown in Figures 5A to 5D, the wafer table 500 includes an array of outlet assemblies 510, each outlet assembly 510 including a pair of fluid channels 512, 514 for venting gas in opposite directions (indicated by arrows in Figure 5A) to support the semiconductor wafer 200. Specifically, each outlet assembly 510 includes a first fluid channel 512 configured to vent gas in a first direction and a second fluid channel 514 configured to vent gas in a second direction opposite to the first direction.

[0049] As described above, the first set of fluid outlets is configured to discharge gas so that the exhaust gas supports the semiconductor wafer 200 without physical contact with the wafer table 500, and the second set of fluid outlets is configured to discharge gas so that the exhaust gas rotates the semiconductor wafer 200 while it is supporting it.

[0050] For example, the first set of fluid outlets includes a pair of fluid channels 512, 514 in the outlet assembly 510, and the gas discharged from the pair of fluid channels 512, 514 supports the semiconductor wafer 200 against the wafer table 500. For example, the second set of fluid outlets includes fluid channels 512, 514 in each outlet assembly 510, which discharge gas in their respective directions, thereby rotating the semiconductor wafer 200 supported by the wafer table 500. The air controller 150 is configured to control the gas discharge from the first and second sets of fluid outlets, i.e., the fluid channels 512, 514, thereby controlling the support and rotation of the semiconductor wafer 200.

[0051] In one embodiment, the gas discharged from the first set of fluid outlets, i.e., the pair of fluid channels 512 and 514, causes the semiconductor wafer 200 to float above the wafer table 500. A spatial gap 520 is formed between the floating semiconductor wafer 200 and the surface of the wafer table 500. Furthermore, the gas discharged from the second set of fluid outlets, i.e., the fluid channels 512 and 514, rotates the semiconductor wafer 200 while it is floating above the wafer table 500. Therefore, the wafer table 500 floats and rotates the semiconductor wafer 200 by discharging gas in the same manner as the wafer table 300 described above.

[0052] In one embodiment shown in Figures 6A and 6B, the gas discharged from a first set of fluid outlets, i.e., the pair of fluid channels 512 and 514, grips the semiconductor wafer 200 below the wafer table 500. A spatial gap 520 is formed between the gripped semiconductor wafer 200 and the surface of the wafer table 500. Furthermore, the gas discharged from a second set of fluid outlets, i.e., the fluid channels 512 and 514, rotates the semiconductor wafer 200 while it is gripped below the wafer table 500.

[0053] The non-contact gripping of the semiconductor wafer 200 beneath the wafer table 500 is based on Bernoulli's principle in fluid dynamics. According to Bernoulli's principle, when gas flows at high speed over the surface of an object, the local pressure on the object's surface decreases. If high pressure exists on the opposite side of the object, the high-speed airflow becomes a resultant force toward the object's surface. If this force exceeds the weight of the object, the object is pulled toward the low-pressure side. The wafer table 500 creates a local low-pressure side by flowing gas across the entire upper surface of the semiconductor wafer 200. The lower surface of the semiconductor wafer 200 is at ambient pressure, such as atmospheric pressure, which is higher than the low-pressure side. This creates a resultant force from the lower surface to the upper surface of the semiconductor wafer 200. Since this resultant force exceeds the weight of the semiconductor wafer 200, the semiconductor wafer 200 is pulled toward the wafer table 500. In this way, the wafer table 500 uses the gas flow to grip the semiconductor wafer 200 beneath it without physical contact, maintaining a spatial gap 520 between them.

[0054] For example, referring to Figure 5B, gas is discharged from the first pair 512a, 514a of the fluid channels, the second pair 512b, 514b of the fluid channels, the third pair 512c, 514c of the fluid channels, and the fourth pair 512d, 514d of the fluid channels, thereby causing the semiconductor wafer 200 to float above the wafer table 500 or to grip the semiconductor wafer 200 below the wafer table 500.

[0055] For example, gas is discharged from the first fluid channels 512a, 512b and the second fluid channels 514c, 514d, causing the suspended / gripped semiconductor wafer 200 to rotate counterclockwise. For example, in the first outlet assembly 510a, the gas flow rate from the first fluid channel 512a is made higher than that from the second fluid channel 514a, thereby enabling the counterclockwise rotation of the suspended / gripped semiconductor wafer 200. Alternatively, the gas flow from the second fluid channel 514a may be blocked.

[0056] For example, gas is discharged from the first fluid channels 512c, 512d and the second fluid channels 514a, 514b, causing the suspended / gripped semiconductor wafer 200 to rotate clockwise. For example, in the first outlet assembly 510a, the gas flow rate from the second fluid channel 512b is made higher than that from the first fluid channel 512a to enable the floating / gripped semiconductor wafer 200 to rotate clockwise. Alternatively, the gas flow from the first fluid channel 512a may be blocked.

[0057] It will be understood that the flow rate of the gas circulating through the air piping 140 for levitating / grasping / rotating the semiconductor wafer 200 and discharged from the fluid outlet may vary depending on the intended end use of the wafer table 500. For example, the flow rate may be in the range of 10 L / min to 200 L / min, but is not limited to this range.

[0058] The various aspects of the wafer table 300 described above are also applicable to the wafer table 500, and for the sake of brevity, further details will be omitted.

[0059] As described above with respect to the wafer table 300, the system 100 includes air piping 140 that is fluidically connected to the fluid outlet of the wafer table 500. For example, as shown in Figure 6A, the air piping 140 may include separate air pipes that are fluidically connected to each of the fluid channels 512 and 514 in the wafer table 500. Similarly, the air controller 150 controls the gas discharge from the fluid channels 512 and 514, thereby controlling the support and rotation of the semiconductor wafer 200.

[0060] The system 100 and method 400 described herein advantageously enable contactless handling of semiconductor wafers 200. That is, no physical contact occurs between the semiconductor wafer 200 and the wafer tables 300, 500. Furthermore, the system 100 can rotate and align the semiconductor wafer 200 without any physical contact with it. This prevents the adhesion of unwanted dust particles that can adhere to the semiconductor wafer 200 and cause contamination and quality degradation. Because there is no physical contact, accidental damage to the semiconductor wafer 200 is also prevented. The risk of contamination and damage to the semiconductor wafer 200 is reduced, resulting in improved quality and yield. The processing time of the semiconductor wafer 200 in semiconductor manufacturing is also shortened, and the yield output and chip yield of each semiconductor wafer 200 are improved.

[0061] In the detailed description above, embodiments of the present disclosure relating to systems and methods for non-contact handling of semiconductor wafers have been described with reference to the accompanying drawings. The descriptions of various embodiments herein are not intended to point out or limit any particular expression of the present disclosure, but merely to illustrate non-limiting examples of the present disclosure. The present disclosure aims to address at least one of the problems and challenges relating to the prior art described above. Although only some embodiments of the present disclosure are disclosed herein, those skilled in the art will understand that various changes and / or modifications can be made to the disclosed embodiments based on the present disclosure, and that these will not depart from the scope of the present disclosure. Accordingly, the scope of the present disclosure and the scope of the following claims are not limited to the embodiments described herein.

Claims

1. A system for contactless handling of semiconductor wafers, A wafer table configured to support semiconductor wafers without physical contact and including multiple fluid outlets configured to discharge gases, A plurality of air pipes, which are fluidically connected to the fluid outlet in order to supply gas to the fluid outlet, The system includes an air controller configured to control the gas flow within the air piping and thereby selectively discharge gas from the fluid outlet, The first set of fluid outlets is configured to discharge gas flowing from the air piping, thereby supporting the semiconductor wafer against the wafer table without causing physical contact between the semiconductor wafer and the wafer table. The second set of fluid outlets is configured to discharge gas flowing from the air piping, thereby causing the gas discharged from the second set of fluid outlets to rotate the semiconductor wafer while the semiconductor wafer is supported by the wafer table without physical contact. The air controller is configured to control the discharge of gas from the first and second sets of fluid outlets, thereby controlling the support and rotation of the semiconductor wafer.

2. The first set of fluid outlets includes a first fluid channel having a shape that causes the exhaust gas to levitate the semiconductor wafer above the wafer table. The system according to claim 1, wherein the second set of fluid outlets includes a second fluid channel having a shape that causes the exhaust gas to rotate the semiconductor wafer while it is suspended above the wafer table.

3. The system according to claim 2, wherein the first fluid channel includes one or more linear fluid channels.

4. The system according to claim 2 or 3, wherein the second fluid channel includes one or more bending fluid channels.

5. The system according to claim 1, wherein the wafer table comprises an array of exit assemblies, each exit assembly comprising a pair of fluid channels for discharging gas in opposite directions to support the semiconductor wafer.

6. The first set of fluid outlets comprises the pair of fluid channels of the outlet assembly, and the gas discharged from the pair of fluid channels supports the semiconductor wafer against the wafer table. The system according to claim 5, wherein the second set of fluid outlets comprises fluid channels of each outlet assembly that discharge gas in each direction, and the gas discharged from each fluid channel in each direction rotates the semiconductor wafer supported by the wafer table.

7. The gas discharged from the first set of fluid outlets causes the semiconductor wafer to float above the wafer table. The system according to claim 6, wherein the gas discharged from the second set of fluid outlets is suspended above the wafer table while the semiconductor wafer is rotated.

8. The gas discharged from the first set of fluid outlets grips the semiconductor wafer below the wafer table. The system according to claim 6, wherein the gas discharged from the second set of fluid outlets rotates the semiconductor wafer while it is held below the wafer table.

9. The system according to any one of claims 1 to 8, wherein the air piping includes air piping configured to brake the rotation of the semiconductor wafer.

10. The system according to any one of claims 1 to 9, wherein the wafer table is placed on a fixed chuck.

11. The system according to claim 10, wherein the fixed chuck is equipped with a rotational speed sensor for measuring the rotational speed of the semiconductor wafer.

12. The system according to any one of claims 1 to 9, further comprising an arm mechanism connected to the wafer table and configured to move the wafer table on which the semiconductor wafer is placed from a first station to a second station.

13. The system according to claim 12, wherein the controlled rotation of the semiconductor wafer enables alignment of the semiconductor wafer with respect to the second station.

14. The system according to claim 13, further comprising a set of alignment sensors for controlling the alignment of the semiconductor wafer.

15. The system according to claim 14, wherein the alignment sensor is configured to detect alignment elements of the semiconductor wafer, and the air controller is configured to stop the rotation of the semiconductor wafer in response to the alignment sensor detecting the alignment elements.

16. The system according to claim 15, further comprising a set of auxiliary sensors that cooperate with the alignment sensor to control the alignment of the semiconductor wafer.

17. The system according to claim 16, wherein the auxiliary sensor is configured to detect the alignment element of the semiconductor wafer prior to the alignment sensor, and the air controller is configured to decelerate the rotation of the semiconductor wafer in response to the auxiliary sensor detecting the alignment element.

18. The system according to any one of claims 15 to 17, wherein the alignment element includes a notch at the edge of the semiconductor wafer.

19. The system according to any one of claims 1 to 18, wherein the gas circulating in the air piping contains clean dry air or nitrogen.

20. A method for non-contact handling of semiconductor wafers, A step of aligning a semiconductor wafer and a wafer table relative to each other, wherein the wafer table includes a plurality of fluid outlets configured to discharge gases, The steps include using an air controller to control the gas flow in multiple air pipes fluidly connected to the fluid outlet, thereby selectively discharging gas from the fluid outlet, The steps include: discharging gas flowing from the air piping from the first set of fluid outlets, thereby supporting the semiconductor wafer against the wafer table without the gas discharged from the first set of fluid outlets causing physical contact between the semiconductor wafer and the wafer table; The steps include: discharging gas flowing from the air piping from the second set of fluid outlets, thereby causing the gas discharged from the second set of fluid outlets to rotate the semiconductor wafer while the semiconductor wafer is supported by the wafer table without physical contact; A method comprising the steps of controlling the discharge of gas from the first and second sets of fluid outlets using the air controller, thereby controlling the support and rotation of the semiconductor wafer.

21. A step of suspending the semiconductor wafer above the wafer table using gas discharged from a first set of fluid outlets, wherein the first set of fluid outlets includes a first fluid channel, The method according to claim 18, further comprising the step of rotating the semiconductor wafer, which is suspended above the wafer table, using gas discharged from a second set of fluid outlets, wherein the second set of fluid outlets includes a second fluid channel.

22. A step of suspending the semiconductor wafer above the wafer table using gas discharged from a first set of fluid outlets, wherein the first set of fluid outlets comprises a pair of fluid channels in an array of outlet assemblies of the wafer table. The method according to claim 18, further comprising the steps of rotating a semiconductor wafer while it is suspended above the wafer table using gas discharged in each direction from a second set of fluid outlets, wherein the second set of fluid outlets comprises fluid channels of each outlet assembly that discharge gas in each direction.

23. A step of gripping the semiconductor wafer below the wafer table using gas discharged from a first set of fluid outlets, wherein the first set of fluid outlets comprises a pair of fluid channels in an array of outlet assemblies of the wafer table; The method according to claim 18, further comprising the step of rotating the semiconductor wafer, which is held below the wafer table, using gas discharged in each direction from a second set of fluid outlets, wherein the second set of fluid outlets includes fluid channels of each outlet assembly that discharge gas in each direction.

24. The method according to any one of claims 20 to 23, further comprising the step of placing the wafer table on a fixed chuck.

25. The method according to claim 24, further comprising the step of measuring the rotational speed of the semiconductor wafer.

26. A step of moving an arm mechanism to a first station, aligning the wafer table with the semiconductor wafer, and receiving the semiconductor wafer, wherein the arm mechanism is connected to the wafer table. The method according to any one of claims 20 to 23, further comprising the step of moving the wafer table from the first station to the second station while the semiconductor wafer is supported by the wafer table without physical contact.

27. The method according to claim 26, further comprising the step of aligning the semiconductor wafer with respect to the second station by controlled rotation of the semiconductor wafer.

28. A step of detecting the alignment elements of the semiconductor wafer using an alignment sensor, The method according to claim 27, further comprising the step of stopping the rotation of the semiconductor wafer in response to the detection of the alignment element.

29. The steps include: first detecting the alignment elements of the semiconductor wafer using a set of alignment sensors; The steps include: Decelerating the rotation of the semiconductor wafer in response to the detection of the alignment element; The steps include: using a set of spare sensors to re-detect the alignment elements of the semiconductor wafer; The method according to claim 27, further comprising the step of stopping the rotation of the semiconductor wafer in response to the re-detection of the alignment element.

30. The method according to claim 28 or 29, wherein the alignment element includes a notch at the edge of the semiconductor wafer.

31. The method according to any one of claims 20 to 30, wherein the gas circulating in the air piping contains clean dry air or nitrogen.

Images