Wafer Polishing System

Abstract

The wafer polishing system includes at least one polishing unit, which includes a fixed work position and at least two polishing modules. The polishing modules located on both sides of the fixed work position include a polishing platform and a polishing arm. The polishing arm transports the wafer to the polishing platform to perform the polishing process. The polishing arms of the polishing modules on both sides are located diagonally opposite to the fixed work position, and each of them swings between the fixed work position and the polishing platform to transport the wafer, and the movable areas of each polishing arm have an overlapping portion. The polishing arms of each polishing module of the present invention are individually controlled, which is more stable and more flexible. With only one fixed work position, multiple polishing modules can work together to realize the polishing process of a single or multiple wafers, which greatly shortens the moving path of the polishing process, minimizes the transport process time, and improves the polishing efficiency.

Description

[Technical Field]

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

[0002] Chemical mechanical planarization (CMP) is one of the seven important tools in integrated circuit manufacturing.

[0003] Currently, chemical mechanical polishing technology has evolved into a technology that integrates online measurement, online endpoint detection, cleaning, and other technologies, and is a product of the development of integrated circuit miniaturization, multi-layering, thinning, and planarization processes. It is also a process technology necessary for improving productivity, reducing manufacturing costs, and globally planarizing substrates as wafers move from 200mm to 300mm and even larger diameters.

[0004] A chemical mechanical polishing (CMP) system typically consists of a semiconductor device front-end module (FEM), a cleaning unit, and a polishing unit. The FEM primarily includes a wafer cassette, a sheet transport robot arm, and an air purification system. The cleaning unit primarily includes a variable number of megasonic cleaning elements, a roll brush cleaning element, a drying element, and a device for transporting wafers between these elements. The polishing unit typically includes components such as a table, a polishing disk, a polishing head, a polishing arm, a dresser, and a polishing liquid arm, with each component positioned on the table according to its processing position. In actual wafer processing, the spatial arrangement of the polishing unit and modules such as cleaning and wafer transport has been found to have a significant impact on the overall polishing production of the CMP system. Wafer transport between the polishing unit and the outside, and between polishing units, is typically achieved using a removable stage.

[0005] Regarding the spatial layout of the loading table and polishing units, most commercially available systems have a loading table and three polishing units arranged in a square. As shown in Figure 1, four polishing heads are mounted on a cross-shaped rotary table, meaning that each wafer is loaded into the polishing area of ​​each polishing head one by one. Each loading table must provide loading and unloading services for three polishing units. This means that the number of polishing heads and polishing tables cannot be adjusted, and the polishing time of each polishing head cannot be controlled individually. This results in poor time efficiency, low flexibility, and a tendency for liquids on different polishing tables to splash and interact with each other, affecting the polishing results and complicating the process. Summary of the Invention [Problem to be solved by the invention]

[0006] To solve the technical problems of the prior art, the present invention provides a wafer polishing system in which each polishing module is individually controlled, allowing for flexible control, the polishing modules share a fixed working position, the equipment space is compact, and the wafer movement trajectory is designed to improve the transport efficiency and polishing efficiency. [Means for solving the problem]

[0007] The technical solutions adopted by the present invention to solve the conventional technical problems are as follows: A wafer polishing system includes at least one polishing unit. The polishing unit includes a fixed working position and at least two polishing modules, the polishing modules being located on either side of the fixed working position. Each of the polishing modules includes a polishing platform and a polishing arm. The polishing arm is configured to move the wafer relative to the polishing platform to accomplish the polishing process. The polishing arms of the polishing modules on both sides are positioned diagonally to the fixed working position, and the polishing arms can each swing between the fixed working position and the polishing platform to realize wafer transportation, and the movable areas of each of the polishing arms have an overlapping portion.

[0008] Furthermore, the polishing arm of one of the polishing modules retrieves the wafer from the fixed working position, completes the polishing process, and returns the wafer to the fixed working position along a first locus. The polishing arm of the other polishing module retrieves the wafer from the fixed working position, completes the polishing process, and returns the wafer to the fixed working position along a second locus. The running directions of the first locus and the second locus are approximately S-shaped.

[0009] Furthermore, the overlapping portion of the movable area is eye-shaped, and the central axis of the fixed working position passes through the center of the overlapping portion.

[0010] Furthermore, the movable locus along which the center of the wafer passes in the first locus and the movable locus along which the center of the wafer passes in the second locus have only one contact point.

[0011] Furthermore, the swing angle of the polishing arm is less than 180°.

[0012] Furthermore, the fixed working position is a lifting structure, and when the fixed working position does not interact with the polishing arm to load or unload a wafer, it is located at a position below the plane where the polishing platform is located.

[0013] Furthermore, the number of the polishing modules is two, and the first polishing arm retrieves the wafer from the fixed working position and polishes it on the first polishing platform, and after completing the polishing process in the polishing module, the first polishing arm returns the wafer to the fixed working position and moves from the fixed working position, and the second polishing arm retrieves the wafer from the fixed working position and polishes it on the second polishing platform, and at the same time, another wafer is placed at the fixed working position.

[0014] Furthermore, the first polishing arm returns the polished wafer to the fixed working position and then rotates to a cleaning position for cleaning, and the second polishing arm returns the polished wafer to the fixed working position and then rotates to a cleaning position for cleaning.

[0015] Furthermore, the number of the polishing modules is at least two, and a first polishing arm picks up a wafer from the fixed working position and polishes it on the first polishing platform, while another wafer is placed at the fixed working position, and then a second polishing arm picks up the other wafer from the fixed working position and polishes it on the second polishing platform.

[0016] Furthermore, the number of the polishing units is three, and the polishing units are arranged adjacent to each other in the longitudinal direction, and each of the polishing units is provided with two of the polishing modules.

[0017] Furthermore, a line connecting the centers of the polishing platforms included in each of the two polishing modules of the single polishing unit intersects with the central axis of the fixed working position.

[0018] The beneficial effects of the present invention are as follows: 1) The polishing arms of each polishing module are individually controlled, resulting in higher stability and flexibility. 2) The operating time of each polishing module can be individually controlled, adapting to different polishing requirements. 3) The polishing fluids of different polishing modules do not affect each other, resulting in higher polishing effectiveness. 4) The overall movement flow is simple and smooth, the movement stroke of the entire polishing process is compact, and polishing efficiency is high. 5) The layout in which multiple polishing units are arranged adjacently in the longitudinal direction allows any number of polishing units or any number of polishing modules to be selected as needed to complete the entire polishing flow, adapting to different process needs. 6) The layout is more compact, leaving more space for cleaning stations. 7) A single fixed working station is sufficient to achieve the polishing process of single or multiple wafers with multiple polishing modules working together, significantly shortening the movement path of the polishing process, minimizing the transfer process time, and improving polishing efficiency. The fixed working station has a simple structure, is easy to maintain, and is the lowest cost. It also allows the working station and polishing modules to be located closer to each other, thereby reducing the overall volume of the device. Furthermore, throughout the entire process, the wafer travels only along an S-shaped trajectory, minimizing the travel distance as much as possible, effectively reducing liquid evaporation from the wafer surface and the possibility of impurities falling onto the wafer. Furthermore, because the two polishing arms only have a common area at the fixed work position, before placing the wafer on the fixed work table, the other robot arm waits to load in a non-common area near the fixed work position, thereby grasping the wafer in the shortest time and maximizing overall polishing efficiency. 8) One fixed work position can realize wafer loading and unloading from the polishing modules on both sides, eliminating the need to move the work position to access the left or right polishing module, and providing more accurate control. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram of a wafer polishing system in the prior art. [Figure 2]FIG. 1 is a schematic view of a polishing unit according to a first embodiment of the present invention. [Figure 3] 10 is a schematic view showing a trajectory of a first polishing arm movable region of the left polishing module in the first embodiment of the present invention. FIG. [Figure 4] FIG. 4 is a schematic view of a first trajectory of the left polishing module in the first embodiment of the present invention. [Figure 5] 3A and 3B are schematic diagrams showing the trajectories of the first and second polishing arm movable regions of the polishing modules on both sides in the first embodiment of the present invention. [Figure 6] FIG. 10 is a schematic view of a second locus of the right polishing module in the first embodiment of the present invention. [Figure 7] 1 is a schematic diagram of a first embodiment of the present invention. [Figure 8] FIG. 1 is a schematic layout diagram of three polishing units according to the present invention. [Figure 9] 1 is a process schematic diagram 1 according to a second embodiment of the present invention. [Figure 10] 2 is a process schematic diagram 2 according to the second embodiment of the present invention. [Figure 11] 3 is a process schematic diagram 3 according to the second embodiment of the present invention. [Figure 12] FIG. 10 is a process schematic diagram according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] In order to allow those skilled in the art to better understand the present invention, the following clearly and completely describes the technical aspects of the embodiments of the present invention in combination with the accompanying drawings, but it is clear that the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without performing creative work shall fall within the scope of protection of the invention.

[0021] First embodiment The wafer polishing system includes at least one polishing unit. As shown in FIG. 2, the polishing unit 1 includes one fixed work position 2 and at least two polishing modules 3, which are located on both sides of the fixed work position 2. Each polishing module 3 includes a polishing platform and a polishing arm. The polishing arm is configured to move the wafer relative to the polishing platform to perform 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 polishing arms of the polishing modules 3 on both sides are positioned diagonally opposite to the fixed work position 2, and each polishing arm can swing between the fixed work position 2 and the polishing platform to transport wafers. The movable areas of the polishing arms overlap. The polishing arm here includes a rotating arm and a polishing head for wafer suction. Because the polishing head moves relative to the rotating arm, more precisely, when the polishing module 3 is polishing a wafer, its polishing arm is positioned diagonally opposite to the fixed work position 2. That is, the rotating arm is always positioned diagonally opposite to the fixed work position 2.

[0022] In this embodiment, the number of polishing modules 3 is two, that is, one polishing module 3 is provided on each side of the fixed work position 2. Taking the direction shown in FIG. 2 as an example, the first polishing module located on the left side of the fixed work position 2 includes a first polishing platform 311 and a first polishing arm 321, and the second polishing module located on the right side includes a second polishing platform 312 and a second polishing arm 322.

[0023] 3 and 4, after the first polishing arm 321 of the first polishing module retrieves the wafer from the fixed working position 2, it rotates counterclockwise to the first polishing platform 311, and after completing the polishing process of the first polishing module, it returns the wafer to the fixed working position 2 along the first locus 41. At this time, the first polishing arm 321 rotates clockwise, and its swing angle is less than 180°.

[0024] Of course, in other embodiments, the first polishing arm 321 also rotates clockwise to move to the first polishing platform 311, and after completing the polishing process of the first polishing module, further rotates counterclockwise to return the wafer to the fixed working position 2.

[0025] 5 and 6, after the second polishing arm 322 of the second polishing module retrieves the wafer from the fixed working position 2, it rotates clockwise to the second polishing platform 321, and after completing the polishing process of the second polishing module, it returns the wafer to the fixed working position 2 along the second locus 42. At this time, the second polishing arm 322 rotates counterclockwise, and its swing angle is less than 180°.

[0026] Of course, in other embodiments, the second polishing arm 322 also rotates counterclockwise to move to the second polishing platform 321, and after completing the polishing process of the second polishing module, rotates further clockwise to return the wafer to the fixed working position 2.

[0027] The first and second loci 41, 42 run in a roughly S-shape, with the central portion of the S-shape located at the fixed work position 2. As shown in FIG. 5, the overlapping portion 5 of the movable area is shaped like an eye, with the central axis of the fixed work position 2 passing through the center 51 of the overlapping portion. The first and second loci 41, 42 are loci with a relatively wide stroke, which includes not only the locus of movement traversed by the outer edge of the polishing arm, but also the locus of movement traversed by any point on the wafer, including the locus of movement traversed by the center of the wafer. In this case, the locus of movement traversed by the center of the wafer has only one contact point, as shown in FIG. 7.

[0028] To prevent the fixed working position 2 from interfering with the movements of the first polishing arm 321 and the second polishing arm 322 of the two polishing modules, the fixed working position 2 is designed to have a lifting structure. When the fixed working position 2 does not interact with the first polishing arm 321 and is not loading or unloading a wafer, the fixed working position 2 is located at a position below the plane on which the first polishing platform 311 is located. When the fixed working position 2 does not interact with the second polishing arm 322 and is not loading or unloading a wafer, the fixed working position 2 is located at a position below the plane on which the second polishing platform 321 is located. The specific lifting structure of the fixed working position 2 can be realized by conventional technology, and therefore will not be described here.

[0029] As shown in FIG. 8, in this embodiment, the number of polishing units 1 is three, and they are arranged adjacent to each other in the longitudinal direction, and each polishing unit 1 is provided with two polishing modules 3 .

[0030] A line connecting the centers of the polishing platforms of the two polishing modules 3 in a single polishing unit 1 intersects with the central axis of the fixed work position 2. That is, a line connecting the center of the first polishing platform 311 and the center of the second polishing platform 321 passes through an extension of the central axis of the fixed work position 2.

[0031] Second embodiment In this embodiment, there are also two polishing modules 3. The first polishing arm 321 of the first polishing module picks up the wafer from the fixed working position 2 and polishes it on the first polishing platform 311, as shown in Fig. 9 . After the polishing process of the first polishing module is completed, the wafer is returned to the fixed working position 2 along the first trajectory 41 and then moved from the fixed working position 2 to the cleaning position while continuing to rotate in the same direction, as shown in Fig. 10 , for cleaning.

[0032] The second polishing arm 322 of the second polishing module retrieves the same wafer from the fixed working position 2 and then polishes it on the second polishing platform 321. After completing the polishing process in the second polishing module, the wafer is returned to the fixed working position 2 along the second trajectory 42 and moves from the fixed working position 2 to the cleaning position while continuing to rotate in the same direction, as shown in FIG.

[0033] Third embodiment In the first and second embodiments, the same wafer is processed, but in this embodiment, different wafers are processed.

[0034] In this embodiment, the number of polishing modules 3 is also two, and the first polishing arm 321 of the first polishing module picks up the first wafer from the fixed working position 2, and then polishes it on the first polishing platform 311, completing the polishing process of the first polishing module.

[0035] At the same time, a second wafer is placed at fixed working position 2 by the robot arm.

[0036] As shown in FIG. 12, the second polishing arm 322 of the second polishing module picks up the second wafer from the fixed working position 2 and then polishes it on the second polishing platform 321, completing the polishing process of the second polishing module.

[0037] The above specific embodiments are used to illustrate the present invention rather than limit the present invention, and any modifications and variations made to the present invention within the purpose of the present invention and the protection scope of the claims will also fall within the protection scope of the present invention. [Explanation of symbols]

[0038] 1: polishing unit, 2: fixed working position, 3: polishing module, 311: first polishing platform, 312: second polishing platform, 321: first polishing arm, 322: second polishing arm, 41: first trajectory, 42: second trajectory, 5: overlapping portion of movable area, 51: center of overlapping portion

Claims

1. 1. A wafer polishing system, comprising: at least one polishing unit; The polishing unit includes a fixed working position and at least two polishing modules; The grinding modules are located on both sides of a fixed working position; each of the polishing modules includes a polishing platform and a polishing arm; the polishing arm is configured to move the wafer relative to the polishing platform to perform a polishing process; The polishing arms of the polishing modules on both sides are positioned diagonally to the fixed working position, and each of the polishing arms can swing between the fixed working position and the polishing platform to transport the wafer, and each of the movable areas of the polishing arms has an overlapping portion, the overlapping portion of the movable area is eye-shaped, and the central axis of the fixed working position passes through the center of the overlapping portion; The fixed working position is an elevation structure, and when the fixed working position does not interact with the polishing arm or perform wafer loading / unloading, it is located at a position below the plane on which the polishing platform is located.

2. the polishing arm of one of the polishing modules retrieves the wafer from the fixed working position, completes the polishing process, and returns the wafer to the fixed working position along a first trajectory; the polishing arm of the other polishing module retrieves the wafer from the fixed working position, completes the polishing process, and returns the wafer to the fixed working position along a second trajectory; 2. The wafer polishing system according to claim 1, wherein the first and second loci are arranged in a generally S-shaped direction.

3. 3. The wafer polishing system according to claim 2, wherein the movable locus along which the center of the wafer passes in the first locus and the movable locus along which the center of the wafer passes in the second locus have only one point of contact.

4. 2. The wafer polishing system according to claim 1, wherein the swing angle of the polishing arm is less than 180 degrees.

5. The number of the polishing modules is two, the polishing modules include a first polishing module and a second polishing module, the first polishing module includes a first polishing platform and a first polishing arm, and the second polishing module includes a second polishing platform and a second polishing arm; 2. The wafer polishing system of claim 1, wherein a first polishing arm retrieves a wafer from the fixed working position and polishes it on a first polishing platform; after completing the polishing process in the polishing module, the first polishing arm returns the wafer to the fixed working position and moves from the fixed working position; and a second polishing arm retrieves the wafer from the fixed working position and polishes it on a second polishing platform while another wafer is placed at the fixed working position.

6. The first polishing arm returns the wafer after the polishing is completed to the fixed working position, and then rotates to a cleaning position and cleans the wafer; 6. The wafer polishing system according to claim 5, wherein the second polishing arm returns the wafer after the polishing is completed to the fixed working position, and then rotates and moves to a cleaning position for cleaning.

7. 2. The wafer polishing system of claim 1, wherein the number of polishing modules is at least two, and a first polishing arm picks up a wafer from the fixed working position and polishes it on the first polishing platform while another wafer is placed on the fixed working position, and then a second polishing arm picks up the other wafer from the fixed working position and polishes it on the second polishing platform.

8. 2. The wafer polishing system according to claim 1, wherein the number of the polishing units is three, the polishing units are arranged adjacent to each other in the longitudinal direction, and each of the polishing units is provided with two of the polishing modules.

9. 9. The wafer polishing system of claim 8, wherein a line connecting the centers of the polishing platforms of the two polishing modules of the single polishing unit intersects with a central axis of the fixed working position.

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