Wafer polishing system

Abstract

The wafer polishing system includes a wafer transport path and at least one polishing unit including at least two polishing modules. The polishing modules located on both sides of the wafer transport path include a polishing platform and a polishing arm. The polishing arm transports the wafer to the polishing platform to perform a polishing process. The wafer transport device can move between at least two working positions of the wafer transport path. The polishing arm of the polishing module retrieves the wafer from the working position in the wafer transport path, completes the polishing process, returns the wafer to the wafer transport path along a first track, and transports the wafer to another working position by the wafer transport device. The polishing arm of the other polishing module retrieves the wafer from the working position along a second track and completes another polishing process. The running directions of the first track, the moving track of the wafer transport device, and the second track are approximately Z-shaped. The present invention has higher stability, higher flexibility, and better polishing effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor integrated circuit chip manufacturing, and particularly relates to a wafer polishing system.

Background Art

[0002] A Chemical Mechanical Planarization (CMP) apparatus is one of the seven important apparatuses in the field of integrated circuit manufacturing.

[0003] Currently, chemical mechanical polishing technology has developed into a chemical mechanical polishing technology that integrates technologies such as on-line measurement, on-line endpoint detection, and cleaning. It is the product of the development of the miniaturization, multi-layerization, thinning, and planarization processes of integrated circuits. Also, the wafer has shifted from 200 mm to 300 mm and even to a larger diameter, and it is also a process technology necessary for improving productivity, reducing manufacturing costs, and global planarization of the substrate.

[0004] A chemical mechanical polishing apparatus generally consists of a front-end module for semiconductor devices, a cleaning unit, and a polishing unit. The front-end module for semiconductor devices mainly includes a sheet cassette for storing wafers, a sheet transfer robot arm, and an air purification system, etc. The cleaning unit mainly includes different numbers of megasonic cleaning members, roll brush cleaning members, drying members, and a device for transferring wafers between each member, etc. The polishing unit generally includes components such as a table, a polishing disk, a polishing head, a polishing arm, a dresser, and a polishing liquid arm, and each component is arranged on the table according to the process processing position. In the actual wafer processing process, it has been found that the spatial arrangement of the polishing unit and modules such as cleaning and wafer transportation has a great impact on the overall polishing production of the chemical mechanical polishing apparatus. The transfer of wafers between the polishing unit and the outside, and the transfer of wafers between the polishing units are generally realized by a detachable platform.

[0005] Regarding the space layout between the loading / unloading table and the polishing unit, a form in which the loading / unloading table and three polishing units are arranged in a square is often commercially available. As shown in FIG. 1, four polishing heads are fixed to a cross-rotating table, which means that one wafer is carried into the polishing area of each polishing head one by one, and one loading / unloading table needs to provide loading / unloading services for three polishing units. Therefore, the number of polishing heads and polishing tables cannot be adjusted, the polishing time of each polishing head cannot be individually controlled, the time efficiency is poor, the flexibility is low, the liquid on different polishing tables is likely to scatter and cause mutual influence, which affects the polishing effect, and the process is complex.

Summary of the Invention

Problems to be Solved by the Invention

[0006] In order to solve the conventional technical problems, the present invention provides a wafer polishing system in which each polishing module included in the wafer polishing system is individually controlled and has high control flexibility. In the wafer polishing system of the present invention, since the polishing modules share a wafer transfer path, the device space becomes compact, and the transfer efficiency can be improved by designing the wafer movement trajectory, and further the polishing efficiency can be improved.

Means for Solving the Problems

[0007] The technical solutions adopted by the present invention to solve the conventional technical problems are as follows. A wafer polishing system, including at least one polishing unit, The polishing unit includes a wafer transfer path and at least two polishing modules, The polishing modules are located on both sides of the wafer transfer path. The polishing module includes a polishing platform and a polishing arm. The polishing arm is configured to be movable relative to the polishing platform to perform a polishing process on the wafer, The wafer transfer path has at least two working positions, and the wafer transfer device is configured to be movable between the working positions. After the polishing arm of the one polishing module acquires a wafer from one of the working positions in the wafer transfer path, the polishing process is completed, and after the wafer is returned to the wafer transfer path along the first trajectory, the wafer transfer device is moved to transfer the wafer to another working position. The polishing arm of the other polishing module is configured to complete the other polishing process after acquiring a wafer from the other working position along the second trajectory. The traveling directions of the first trajectory, the movement trajectory of the wafer transfer device, and the second trajectory are substantially Z-shaped.

[0008] Furthermore, the number of the working positions is the same as the number of the polishing arms.

[0009] Furthermore, the polishing arms of the polishing module are symmetrically provided about the center point of the line connecting the first working position and the last working position in the wafer transfer path.

[0010] Furthermore, the first trajectory is an arc, or the first trajectory is a straight line, or the first trajectory is an approximate straight line. The second trajectory is an arc, or the second trajectory is a straight line, or the second trajectory is an approximate straight line.

[0011] Furthermore, in order to execute the polishing process, the polishing arm transports the wafer with respect to the polishing platform while reciprocating along an arc-shaped trajectory, and the arc-shaped trajectory is concentric with the arc-shaped first trajectory or the second trajectory.

[0012] Furthermore, the number of the wafer transfer devices is one.

[0013] Furthermore, the number of the polishing modules is two, and the polishing arms of the two polishing modules are both provided close to the wafer transfer path and are provided at diagonal positions across the wafer transfer path.

[0014] Furthermore, after the first polishing arm acquires the wafer from the first working position, it polishes the wafer on the first polishing platform. After completing the polishing process of the polishing module, the first polishing arm returns the wafer to the first working position. The wafer transfer device moves the wafer from the first working position to the second working position. The second polishing arm acquires the wafer from the second working position and polishes it on the second polishing platform. At the same time, another wafer is moved from the second working position to the first working position by the wafer transfer device, so that the first polishing arm continuously acquires and polishes the other wafer.

[0015] Furthermore, the wafer transfer device moves the wafer from the first working position to the second working position. Subsequently, after the cleaning is completed at the first working position, the first polishing arm acquires a new wafer and transports the new wafer to the first polishing platform for polishing.

[0016] Furthermore, after the first polishing arm acquires the wafer from the first working position, it polishes the wafer on the first polishing platform. After completing the polishing process of the polishing module, the first polishing arm returns the wafer to the first working position. The first polishing arm moves to the first polishing platform. The wafer transfer device moves the wafer from the first working position to the second working position. The second polishing arm acquires the wafer from the second working position and polishes it on the second polishing platform. The wafer transfer device moves from the second working position to the first working position. Another wafer is arranged on the wafer transfer device and waits for the first polishing arm to move to the first working position to acquire the arranged other wafer.

[0017] Furthermore, after the wafer transfer device moves from the first working position, the first polishing arm is cleaned at the first working position and then moves to the first polishing platform.

[0018] Furthermore, after the first polishing arm acquires the wafer from the first working position, it polishes the wafer on the first polishing platform. After completing the polishing process of the polishing module, the first polishing arm returns the wafer to the first working position, and the wafer transfer device moves the wafer from the first working position to the second working position. The second polishing arm acquires the wafer from the second working position and polishes it on the second polishing platform. The wafer transfer device moves from the second working position to the first working position, the first polishing arm moves to the first polishing platform, another wafer is placed on the wafer transfer device, and the first polishing arm waits to move to the first working position to acquire the placed another wafer.

[0019] Furthermore, before another wafer is placed on the wafer transfer device, the first polishing arm is cleaned.

[0020] Furthermore, the number of the polishing units is two or more, and the two or more polishing units are arranged in sequence along the direction in which the wafer transfer path extends.

[0021] The beneficial effects of the present invention are as follows. 1) The polishing arms of each polishing module are individually controlled, with higher stability and flexibility. 2) The operating time of each polishing module can be individually controlled to adapt to different polishing requirements. 3) The polishing liquids between different polishing modules do not affect each other, resulting in a higher polishing effect. 4) The overall trajectory of the operation flow is simple and smooth, the moving stroke of the entire polishing process is compact, and the polishing efficiency is high. 5) The layout in which a plurality of polishing units are arranged in sequence along the wafer transfer path allows any number of polishing units to be selected as needed, or any number of polishing modules can be selected to perform the entire polishing flow, and it can adapt to the demands of different processes.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

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Figure 8

Modes for Carrying Out the Invention

[0023] In order to enable those skilled in the art to better understand the present invention, hereinafter, the technical aspects in the embodiments of the present invention will be clearly and completely described in combination with the accompanying drawings. However, it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained on the premise that those skilled in the art do not perform creative labor shall fall within the protection scope of the present invention.

[0024] First Embodiment A wafer polishing system, including at least one polishing unit 1. As shown in Figure 2, the polishing unit 1 includes a wafer transfer path 2 and at least two polishing modules 3. The polishing modules 3 are located on both sides of the wafer transfer path 2. The polishing module 3 includes a polishing platform and a polishing arm. The polishing arm is configured to be movable relative to the polishing platform for executing the polishing process. The movement here includes the wafer moving synchronously with the polishing arm, and also includes the relative movement between the wafer and the polishing arm. The wafer transfer path 2 has at least two working positions, and the wafer transfer device is configured to be movable between at least two working positions.

[0025] In this embodiment, the number of working positions is the same as the number of polishing arms. The polishing arms of the polishing module 3 are symmetrically provided around the central point of the line connecting the first working position and the last working position.

[0026] The polishing arm of one polishing module 3 acquires a wafer from a working position in the wafer transfer path 2 along the first trajectory 51, and then completes the polishing process on the polishing platform of the polishing module 3. Subsequently, the polished wafer is returned to the wafer transfer path 2 along the first trajectory 51, the wafer transfer device is moved, and the wafer in the wafer transfer path 2 is transferred to another working position. The polishing arms of other polishing modules 3 acquire wafers from other working positions in the wafer transfer path 2 along the second trajectory 53, and then complete the current polishing process on the polishing platform of the polishing module 3.

[0027] As shown in FIG. 3, the traveling directions of the first trajectory 51, the moving trajectory 52 of the wafer transfer device, and the second trajectory 53 are substantially Z-shaped. Here, "substantially" means that the first trajectory 51, the moving trajectory 52 of the wafer transfer device, and the second trajectory 53 do not necessarily have to be perfectly straight, and may be curves with small waves, arcs, etc., but when magnified, they are linearly moving as a whole tendency.

[0028] In this embodiment, the number of wafer transfer devices is one. The number of polishing modules 3 in one polishing unit 1 is two, and the polishing arms of the two polishing modules 3 are both provided close to the wafer transfer path 2 and along the corners at diagonal positions across the wafer transfer path 2. As shown in FIG. 2, the working positions include a first working position 41 and a second working position 42, the polishing arms include a first polishing arm 321 and a second polishing arm 322, and the polishing platforms include a first polishing platform 311 and a second polishing platform 312.

[0029] As shown in FIG. 3, the first trajectory 51 is an arc, and the second trajectory 53 is also an arc. At this time, in order to execute the polishing process, the first polishing arm 321 reciprocates along the arc-shaped trajectory while transporting the wafer with respect to the first polishing platform 311. The arc-shaped trajectory is concentric with the first trajectory 51, and thus on the same circumference. Alternatively, relative movement occurs between the first polishing arm 321 and the wafer to form an arc-shaped trajectory, and then the relative movement between the two stops, and the wafer is transported along the first trajectory 51 by the first polishing arm 321. The second polishing arm 322 transports the wafer with respect to the second polishing platform 312 while reciprocating along the arc-shaped trajectory in order to execute the polishing process. The arc-shaped trajectory is concentric with the second trajectory 53, and thus on the same circumference. Alternatively, relative movement occurs between the second polishing arm 322 and the wafer to form an arc-shaped trajectory, and then the relative movement between the two stops, and the wafer is transported along the first trajectory 51 by the second polishing arm 322.

[0030] As shown in FIG. 4, the first trajectory 51 is a straight line, and precisely it may be an approximate straight line. At this time, while the first polishing arm 321 transports and moves the wafer, relative movement occurs between the wafer and the first polishing arm 321 to make the first trajectory 51 a straight line. The second trajectory 53 is also a straight line, and precisely it is an approximate straight line. At this time, while the second polishing arm 322 transports and moves the wafer, relative movement occurs between the wafer and the second polishing arm 322 to make the second trajectory 53 a straight line. The first trajectory 51 and the second trajectory 53 are straight lines, minimizing the relative movement stroke of the wafer and resulting in higher polishing efficiency.

[0031] Also, while the first polishing arm 321 transports and moves the wafer, relative movement occurs between the wafer and the first polishing arm 321, and the distance of the relative movement is configured to be settable as required, making the first trajectory 51 an irregular line. Similarly, the second trajectory 53 can also be an irregular line.

[0032] As shown in FIG. 5, the number of polishing units 1 may be two or more, and they are arranged in order along the direction in which the wafer transfer path 2 extends.

[0033] As shown in FIG. 6, on the premise of the system layout, the operation flow of the wafer polishing system may be as follows. After the first polishing arm 321 acquires a wafer at the first working position 41, it polishes the wafer on the first polishing platform 311. After completing the polishing process of the polishing module 3, the first polishing arm 321 returns the wafer to the first working position 41, and the wafer transfer device (not shown) moves from the first working position 41 to the second working position 42. The first polishing arm 321 may continue to be left at the first working position 41, or the cleaning may be completed here. After the second polishing arm 322 acquires a wafer from the second working position 42, it performs polishing on the second polishing platform 312. At the same time, another wafer is placed on the wafer transfer device, which may be assisted by the robot arm. When the wafer transfer device moves from the second working position 42 to the first working position 41, the first polishing arm 321 continues to acquire and polish other wafers at the first working position 41.

[0034] By executing the above operation flow, the following effects are achieved. 1) When it is not necessary to reverse the first polishing arm 321, it is possible to realize the continuous transfer of the wafer between the first working position 41 and the second working position 42. Each time the first polishing arm 321 rotates in the wafer transfer path 2, it completes the unloading of one wafer and the loading of one wafer with respect to the polishing platform. 2) The wafer transfer device realizes flexible movement between the first working position 41 and the second working position 42, and the wafer transfer device is utilized to the maximum extent to complete the unloading of one wafer and the loading of one wafer with respect to the polishing platform at each working position. 3) The first polishing arm 321, the second polishing arm 322, and the wafer transfer device all do not take an idle stroke. Through a clever design, the utilization rates of space, time, and components are all maximized.

[0035] Second Embodiment As shown in Fig. 7, this embodiment has the same layout as the first embodiment, and the difference lies in the operation flow of the wafer polishing system. The operation flow is as follows. After the first polishing arm 321 acquires the wafer at the first working position 41, it polishes the wafer on the first polishing platform 311. After completing the polishing process of the polishing module 3, the first polishing arm 321 returns the wafer to the first working position 41, the first polishing arm 321 returns to the first polishing platform 311, and the wafer transfer device moves from the first working position 41 to the second working position 42. After the second polishing arm 322 acquires the wafer from the second working position 42, it performs polishing on the second polishing platform 312. The empty wafer transfer device moves from the second working position 42 to the first working position 41, and another wafer is placed on the wafer transfer device. The first polishing arm 321 rotates from the first polishing platform 311 to the first working position 41 to acquire and polish another wafer.

[0036] After the wafer transfer device moves from the first working position 41, the first polishing arm 321 can rotate from the first polishing platform 311 to the first working position 41 and be cleaned. After the cleaning is completed, the first polishing arm 321 returns to the first polishing platform 311 again and waits to rotate to the first working position 41 next. Naturally, after the wafer transfer device moves from the first working position 41, the first polishing arm 321 still stays on the first polishing platform 311. Before the empty wafer transfer device moves from the second working position 42 to the first working position 41, the first polishing arm 321 rotates from the first polishing platform 311 to the first working position 41 and is cleaned. After the cleaning is completed, the wafer transfer device moves to the first working position 41, and the first polishing arm 321 directly acquires and polishes the wafer.

[0037] With the above setting of the operation flow, after returning the first polishing arm 321 to the first polishing platform 311, it can rotate to the first working position 41 to obtain the wafer. There is one avoidance process in the first polishing arm 321, and there are many possibilities in the process of placing the wafer at the first working position 41, without causing spatial obstacles due to the stay of the first polishing arm 321.

[0038] Third Embodiment As shown in FIG. 8, this embodiment has the same layout as the first embodiment, and the difference lies in the operation flow of the wafer polishing system. The operation flow is as follows. After the first polishing arm 321 obtains the wafer at the first working position 41, it polishes at the first polishing platform 311. After completing the polishing process of the polishing module 3, the first polishing arm 321 returns the wafer to the first working position 41, and the wafer transfer device moves from the first working position 41 to the second working position 42. After the second polishing arm 322 obtains the wafer from the second working position 42, it performs polishing at the second polishing platform 312. The empty wafer transfer device moves from the second working position 42 to the first working position 41, the first polishing arm 321 is returned to the first polishing platform 311, another wafer is placed on the wafer transfer device, and the first polishing arm 321 rotates from the first polishing platform 311 to the first working position 41 to obtain and polish the wafer.

[0039] Before another wafer is placed on the wafer transfer device, the first polishing arm 321 may just complete the cleaning, which may be during the time when the wafer transfer device moves from the first working position 41 to the second working position 42, or during the time when the wafer is polished at the second polishing platform 312, or even during the time when the wafer transfer device moves from the second working position 42 to the first working position 41.

[0040] With the setting of the above operation flow, after returning the first polishing arm 321 to the first polishing platform 311, it can be rotated to the first operation position 41 to obtain the wafer. There is one avoidance process in the first polishing arm 321, and there are more possibilities in the process of placing the wafer at the first operation position 41. No spatial obstacle will occur due to the stay of the first polishing arm 321, and the adaptability will be better.

[0041] The above specific embodiments do not limit the present invention, but are used to explain the present invention. Any modification and change added to the present invention within the purpose of the present invention and the protection scope of the claims are included within the protection scope of the present invention.

Explanation of Reference Numerals

[0042] 1: Polishing unit, 2: Wafer transfer path, 3: Polishing module, 311: First polishing platform, 312: Second polishing platform, 321: First polishing arm, 322: Second polishing arm, 41: First working position, 42: Second working position, 51: First trajectory, 52: Movement trajectory of wafer transfer device, 53: Second trajectory

Claims

1. A wafer polishing system, comprising: at least one polishing unit, wherein the polishing unit includes a wafer transfer path and at least two polishing modules, the polishing modules are located on both sides of the wafer transfer path, each of the polishing modules includes a polishing platform and a polishing arm, the polishing arm is configured to be movable relative to the polishing platform to perform a polishing process on the wafer, the wafer transfer path has at least two working positions, and a wafer transfer device is configured to be movable between the working positions, the number of the working positions is the same as the number of the polishing arms, the number of the polishing modules is two, and the polishing arms of the two polishing modules are both provided close to the wafer transfer path and are provided at diagonal positions sandwiching the wafer transfer path, after the polishing arm of one of the polishing modules obtains a wafer from one of the working positions in the wafer transfer path, completes the polishing process, and returns the wafer to the wafer transfer path along a first trajectory, the wafer transfer device is moved to transfer the wafer to another working position, and after the polishing arm of the other polishing module obtains the wafer from the other working position along a second trajectory, it is configured to complete another polishing process, the running directions of the first trajectory, the moving trajectory of the wafer transfer device, and the second trajectory are substantially Z-shaped, a wafer polishing system, characterized by satisfying the following condition (I) or (II). Condition (I): After the first polishing arm obtains the wafer from the first working position, polishes it on the first polishing platform, and completes the polishing process of the polishing module, the first polishing arm returns the wafer to the first working position, the first polishing arm moves to the first polishing platform, the wafer transfer device moves the wafer from the first working position to the second working position, the second polishing arm obtains the wafer from the second working position, and polishes it on the second polishing platform. The wafer transfer device moves from the second working position to the first working position, and after waiting for another wafer to be placed on the wafer transfer device and for the first polishing arm to move to the first working position, the other wafer thus placed is acquired. Condition (II): After the first polishing arm acquires the wafer from the first working position, it polishes the wafer on the first polishing platform. After the polishing process of the polishing module is completed, the first polishing arm returns the wafer to the first working position, the wafer transfer device moves the wafer from the first working position to the second working position, the second polishing arm acquires the wafer from the second working position, and polishes the wafer on the second polishing platform. The wafer transfer device moves from the second working position to the first working position, the first polishing arm moves to the first polishing platform, another wafer is placed on the wafer transfer device, and after waiting for the first polishing arm to move to the first working position, the other wafer thus placed is acquired.

2. The polishing arm of the polishing module is symmetrically provided about the center point of the line connecting the first working position and the last working position in the wafer transfer path. The wafer polishing system according to claim 1, characterized in that.

3. The first trajectory is an arc, or the first trajectory is a straight line, or the first trajectory is an approximate straight line. The second trajectory is an arc, or the second trajectory is a straight line, or the second trajectory is an approximate straight line. The wafer polishing system according to claim 1, characterized in that.

4. In order to execute the polishing process, the polishing arm reciprocates along an arc-shaped trajectory while transporting the wafer with respect to the polishing platform, and the arc-shaped trajectory is concentric with the arc-shaped first trajectory or the second trajectory. The wafer polishing system according to claim 3, characterized in that.

5. The number of the wafer transfer devices is one. The wafer polishing system according to claim 1, characterized in that.

6. After the first polishing arm acquires the wafer from the first working position, it polishes the wafer on the first polishing platform. After completing the polishing process of the polishing module, the first polishing arm returns the wafer to the first working position. The wafer transfer device moves the wafer from the first working position to the second working position. The second polishing arm acquires the wafer from the second working position and polishes it on the second polishing platform. At the same time, by moving another wafer from the second working position to the first working position by the wafer transfer device, the first polishing arm continuously acquires and polishes the other wafer. The wafer polishing system according to claim 1, characterized in that.

7. The wafer transfer device moves the wafer from the first working position to the second working position. Subsequently, after the cleaning is completed at the first working position, the first polishing arm acquires a new wafer and transports the new wafer to the first polishing platform for polishing. The wafer polishing system according to claim 6, characterized in that.

8. The wafer polishing system according to claim 1, characterized in that it satisfies the condition (I).

9. After the wafer transfer device moves from the first working position, the first polishing arm is cleaned at the first working position and then moves to the first polishing platform. The wafer polishing system according to claim 8, characterized in that.

10. The wafer polishing system according to claim 1, characterized in that it satisfies the condition (II).

11. Before another wafer is placed on the wafer transfer device, the first polishing arm is cleaned. The wafer polishing system according to claim 10, characterized in that.

12. The number of the polishing units is two or more, and the two or more polishing units are arranged in sequence along the direction in which the wafer transfer path extends. The wafer polishing system according to claim 1, characterized in that.

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