Wafer retaining ring

Abstract

The utility model relates to the technical field of semiconductor material processing, in particular to a wafer retaining ring which comprises a retaining ring body, and a hollow area defined by the retaining ring body is used for placing a wafer; the retaining ring body is provided with a first surface and a second surface which are oppositely arranged; the first surface is provided with a diversion trench, and the diversion trench is used for introducing a polishing solution into the wafer placement area; a cavity is formed between the first surface and the second surface of the retaining ring body; the cavity is provided with a first opening end facing the inner ring wall of the retaining ring body and a second opening end facing the outer ring wall of the retaining ring body. The plugging assembly is arranged in the cavity; the blocking assembly comprises a baffle, and the baffle is configured to be capable of selectively stretching out and drawing back at the first opening end. The wafer retaining ring is provided with the telescopic baffle, and the baffle can selectively fill the space between the wafer and the wafer retaining ring and is used for preventing the polishing effect from being affected by accumulation of polishing liquid when the wafer is polished.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor material processing, and in particular to a wafer retaining ring. BACKGROUND

[0002] In the field of semiconductor device preparation, a composite substrate formed by bonding two or more wafers through a bonding technology plays a very key role, and its application scenarios are very wide. In the bonding process, a very important prerequisite is that the wafer bonding surface must be atomically flat. Therefore, the existing technology generally uses the process of chemical mechanical polishing to polish the wafer bonding surface, so as to effectively improve the flatness of the bonding interface.

[0003] In the implementation of the chemical mechanical polishing operation, the wafer usually needs to be placed in a special wafer retaining ring for fixation, so as to ensure the stability and accuracy of the polishing process. However, under the existing conventional wafer processing system, the wafer produced is not a standard complete circle. For example, in order to facilitate clear marking and differentiation of the types of wafers, a flat edge is often deliberately cut on the wafer. This wafer structure with a flat edge will cause a specific problem in the polishing process: a relatively independent space will inevitably be formed between the cut edge of the wafer and the side wall of the wafer retaining ring. Since a large amount of polishing liquid is used in the chemical mechanical polishing process, the existence of the space will easily cause the polishing liquid to accumulate therein. This polishing liquid accumulation phenomenon will significantly affect the polishing rate of the wafer in this area, and thus destroy the flatness uniformity of the entire wafer. Because the polishing rates of different areas are inconsistent in the polishing process, the wafer surface will have flatness differences on the atomic scale, which may have a very adverse chain reaction on the subsequent bonding process and the performance and quality of the semiconductor device, such as increasing the defects of the bonding interface, unstable electrical performance of the semiconductor device, and the like. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at providing a wafer retaining ring for fixing the wafer when the wafer is polished by CMP, and the retaining ring has a telescopic baffle that can selectively fill the space between the wafer and the wafer retaining ring to avoid the accumulation of polishing liquid affecting the polishing effect.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] The wafer retaining ring comprises a retaining ring body, and a hollow region enclosed by the retaining ring body is used for placing the wafer.

[0007] The retaining ring body has a first surface and a second surface arranged oppositely.

[0008] The first surface is provided with a flow guide groove for introducing polishing liquid into a wafer placement area;

[0009] A chamber is provided between the first surface and the second surface of the retaining ring body;

[0010] The chamber has a first open end facing the inner ring wall of the retaining ring body and a second open end facing the outer ring wall of the retaining ring body;

[0011] A plugging assembly is provided in the chamber;

[0012] The plugging assembly includes a baffle configured to selectively extend and retract at the first open end.

[0013] Further, the baffle is configured to selectively abut the sidewall of the wafer.

[0014] Further, when the wafer placed in the hollow area has a flat edge, the baffle is configured to selectively abut the flat edge of the wafer.

[0015] Further, a telescopic rod is further included, one end of the telescopic rod extending into the chamber from the second open end;

[0016] The end of the telescopic rod extending into the chamber is connected with the baffle.

[0017] Further, a guide rail is further included, the guide rail being arranged in the chamber.

[0018] Further, an arc-shaped door is slidingly arranged in the guide rail;

[0019] The arc-shaped door is configured to be selectively opened to selectively plug the first open end.

[0020] Further, the guide rail is arranged on both sides of the first open end;

[0021] Two arc-shaped doors are arranged on the guide rails on both sides of the first open end, respectively.

[0022] Further, a spring is arranged on the side of the arc-shaped door away from the first open end;

[0023] The spring is arranged between the arc-shaped door and the wall of the chamber with an elastic force;

[0024] The elastic force is directed towards the first open end along the direction of the guide rail.

[0025] Further, a pulley transmission assembly includes a plurality of pulleys and a flexible connecting member;

[0026] One end of the flexible connecting member is connected to a driving source;

[0027] The other end of the flexible connecting piece is connected to the arc-shaped door;

[0028] The flexible connecting piece cooperates with the pulley;

[0029] The driving source drives the arc-shaped door to open through the pulley transmission assembly.

[0030] Further, the driving source is the telescopic rod;

[0031] The telescopic rod is configured to have a state one and a state two;

[0032] The state one includes: when the telescopic rod moves towards the first opening end, the flexible connecting piece is pulled, the arc-shaped door moves away from the first opening end along the guide rail, and the spring is compressed;

[0033] The state two includes: when the telescopic rod moves away from the first opening end, the flexible connecting piece is released, the spring is elongated, and the arc-shaped door moves towards the first opening end along the guide rail.

[0034] The utility model discloses beneficial effects:

[0035] The wafer retaining ring is used for fixing the wafer when the wafer is subjected to CMP polishing, the retaining ring has the telescopic baffle, the baffle can selectively fill the space between the wafer and the wafer retaining ring, and the polishing liquid accumulation is avoided to influence the polishing effect. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is the retaining ring body structure schematic view of the utility model;

[0037] Figure 2 It is the plugging assembly structure schematic view of the utility model;

[0038] In the drawing: 1, retaining ring body;11, first opening end;12, second opening end;2, flow guide groove;3, plugging assembly;4, baffle;5, driving part;6, flexible connecting piece;7, pulley;8, guide rail;9, arc-shaped door;10, spring. DETAILED DESCRIPTION

[0039] The utility model will be further explained in detail in combination with the drawings and examples. It can be understood that the specific examples described here are only used to explain the utility model, and not limited to the utility model. In addition, it should be noted that, in order to facilitate the description, only the part related to the utility model is shown in the drawing, not all structures.

[0040] In the description of the utility model, unless another definite provision and limitation, the term "link", "connection", "fix" should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through the intermediate medium, can be two elements inside the communication or two element's interaction relationship.For the ordinary skill in the art, the specific meaning of the above-mentioned terms in the utility model can be understood according to the specific circumstances.

[0041] In the utility model, unless another definite provision and limitation, the first feature is "on" or "under" the second feature can include the first and second features direct contact, also can include the first and second features are not direct contact but contact through the additional feature between them.Moreover, the first feature is "on", "above" and "on" the second feature includes the first feature is directly above and obliquely above the second feature, or just indicates that the horizontal height of the first feature is higher than the second feature.The first feature is "under", "below" and "under" the second feature includes the first feature is directly below and obliquely below the second feature, or just indicates that the horizontal height of the first feature is less than the second feature.

[0042] In the description of the embodiment, the terms "on", "under", "right", etc. Orientation or positional relationship is based on the orientation or positional relationship shown in the drawing, only for the convenience of description and simplification operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the utility model.In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0043] Reference Figure 1 Figure 2 The embodiment of the application provides a wafer retaining ring, and the traditional wafer retaining ring is prone to the problem of polishing liquid accumulation in the space between the wafer and the retaining ring when processing wafers with non-circular features (such as wafers with flat edges), thereby affecting the polishing uniformity and overall quality of the wafer. The wafer retaining ring of the embodiment aims to solve this problem, and effectively controls the polishing liquid accumulation through innovative structural design.

[0044] The retaining ring body 1 is annular in structure, and the hollow area enclosed thereby is specially used for placing wafers. The retaining ring body 1 has oppositely arranged first and second surfaces. The first surface is designed with flow guide grooves 2, which are used to accurately introduce polishing liquid into the wafer placement area, ensuring that the polishing liquid can be uniformly distributed on the wafer surface, thereby realizing an efficient polishing process.

[0045] A cavity is provided between the first surface and the second surface of the retaining ring body 1. The cavity has a first open end 11 facing the inner ring wall of the retaining ring body and a second open end 12 facing the outer ring wall of the retaining ring body. This cavity structure provides a space basis for the subsequent sealing assembly 3 to be arranged and operated.

[0046] When the wafer is placed in the hollow area, the retaining ring body 1 can be adapted to the shape characteristics of the wafer (such as whether there is a flat side). For wafers with flat sides, the sealing assembly 3 of the retaining ring body 1 can seal the gap between the flat side of the wafer and the inner ring wall of the retaining ring body 1.

[0047] The sealing assembly 3 includes a baffle plate 4, which is configured to be selectively extended and retracted at the first open end 11. When it is necessary to prevent the accumulation of polishing liquid between the wafer and the retaining ring, the baffle plate 4 can be extended and can selectively abut the sidewall of the wafer or the flat side of the wafer. For example, when the wafer placed in the hollow area has a flat side, the baffle plate 4 can be extended and abut at the flat side of the wafer, which effectively fills the space that may be formed between the wafer and the retaining ring, avoiding the accumulation of polishing liquid in this area.

[0048] In order to realize the extension and retraction function of the baffle plate 4, a telescopic rod is also provided. One end of the telescopic rod extends into the cavity from the second open end 12, and the end extending into the cavity is connected with the baffle plate 4. By controlling the extension and retraction movement of the telescopic rod, the extension and retraction position of the baffle plate 4 at the first open end 11 can be accurately controlled. The telescopic rod is driven to extend and retract by a driving part 5, which is a driving motor in this embodiment.

[0049] A guide rail 8 is also provided in the cavity, which provides guidance for the sliding of the arc-shaped door 9. The arc-shaped door 9 is slidably arranged on the guide rail 8 and is configured to be selectively opened to selectively seal the first open end 11. The guide rail 8 is arranged on both sides of the first open end 11, and the two arc-shaped doors 9 are arranged on the guide rails 8 on both sides of the first open end 11. This double-arc-shaped door design can more stably and accurately control the opening and closing state of the first open end 11.

[0050] A spring 10 is arranged on the side of the arc-shaped door 9 away from the first open end 11. The spring 10 is arranged between the arc-shaped door 9 and the wall of the cavity with a spring force, which points to the first open end 11 along the direction of the guide rail 8. The arrangement of the spring 10 provides power for the automatic reset of the arc-shaped door 9. When the external driving force disappears, the spring 10 can promote the arc-shaped door 9 to move along the guide rail towards the first open end 11, and restore to the initial sealing state or the predetermined position state.

[0051] In order to realize the drive of the arc-shaped door 9, a pulley transmission assembly is arranged. The pulley transmission assembly comprises a plurality of pulleys 7 and a flexible connecting piece 6. One end of the flexible connecting piece 6 is connected to a driving source (in this embodiment, the driving source is a telescopic rod), and the other end of the flexible connecting piece 6 is connected to the arc-shaped door 9. The flexible connecting piece 6 cooperates with the pulleys 7. When the telescopic rod is in different motion states, the arc-shaped door 9 can be driven to open or close through the pulley transmission assembly. Specifically, when the telescopic rod is in state one, i.e., the telescopic rod moves towards the first opening end 11, the flexible connecting piece 6 is pulled, the arc-shaped door 9 moves away from the first opening end 11 along the guide rail, and the spring 10 is compressed; when the telescopic rod is in state two, i.e., the telescopic rod moves away from the first opening end 11, the flexible connecting piece 6 is released, the spring 10 is elongated, and the arc-shaped door 9 moves towards the first opening end 11 along the guide rail 8.

[0052] When it is necessary to polish a wafer with a flat edge, the driving program of the telescopic rod is started, and the telescopic rod is brought into state one, i.e., the telescopic rod moves towards the first opening end 11. At this time, the flexible connecting piece 6 is pulled, the arc-shaped door is driven to move away from the first opening end along the guide rail through the pulley transmission assembly, the spring is compressed, and the first opening end 11 is gradually opened.

[0053] With the opening of the first opening end 11, the baffle 4 is gradually extended out of the first opening end 11 under the pushing of the telescopic rod, and abuts against the flat edge of the wafer, filling the space between the wafer and the retaining ring.

[0054] Then the CMP polishing operation is started, and the polishing liquid flows uniformly to the surface of the wafer through the flow guide grooves 2 on the first surface of the retaining ring body 1. Since the baffle has blocked the space that may cause the accumulation of the polishing liquid, the polishing liquid can uniformly perform the chemical mechanical polishing action on the surface of the wafer, and the problem of abnormal local polishing rate caused by the accumulation of the polishing liquid does not occur.

[0055] After the polishing is completed, the driving program of the telescopic rod is started again, and the telescopic rod is brought into state two, i.e., the telescopic rod moves away from the first opening end. At this time, the flexible connecting piece is released, the spring is elongated, the arc-shaped door moves towards the first opening end along the guide rail under the action of the spring, and the first opening end is re-blocked. At the same time, the baffle is retracted into the chamber under the driving of the telescopic rod, and is ready for the next wafer polishing operation.

[0056] If the wafer does not have a flat edge, the baffle 4 does not need to extend into the wafer placement area. In order to prevent the accumulation of the polishing liquid in the chamber, the telescopic rod is in state two, i.e., the telescopic rod together with the baffle is retracted into the chamber, the arc-shaped door is closed, the first opening end 11 is blocked, and the wafer polishing operation can be directly performed.

[0057] It can be seen from the above examples that the wafer retaining ring can effectively solve the polishing liquid accumulation problem caused by the space between the wafer and the retaining ring in the CMP polishing process, significantly improves the polishing quality and uniformity of the wafer, and has important application value in the field of semiconductor manufacturing.

[0058] Obviously, the above examples of the utility model are only for clear illustration of the utility model, and are not a limitation on the implementation mode of the utility model. For ordinary skilled in the art, various obvious changes, re-adjustment and replacement can be made without departing from the protection scope of the utility model. Here, all the implementation modes need not and cannot be exhausted. Any modification, equivalent replacement and improvement within the spirit and principle of the utility model should be included in the protection scope of the utility model claim.

Claims

1. A wafer holding ring, characterized in that, include: A retaining ring body is provided, and the hollow region enclosed by the retaining ring body is used to place the wafer. The retaining ring body has a first surface and a second surface that are disposed opposite to each other; The first surface is provided with a flow channel, which is used to introduce polishing fluid into the wafer placement area; A cavity is provided between the first and second surfaces of the retaining ring body; The chamber has a first opening end facing the inner ring wall of the retaining ring body and a second opening end facing the outer ring wall of the retaining ring body; The sealing assembly is disposed in the chamber; The sealing assembly includes a baffle configured to selectively extend and retract at the first opening end.

2. The wafer holding ring according to claim 1, characterized in that: The baffle is configured to selectively abut against the sidewall of the wafer.

3. The wafer holding ring according to claim 1, characterized in that: When the wafer placed in the hollow region has a flat edge, the baffle is configured to selectively abut against the flat edge of the wafer.

4. The wafer holding ring according to claim 1, characterized in that: It also includes a telescopic rod, one end of which extends into the cavity from the second opening end; One end of the telescopic rod that extends into the chamber is connected to the baffle.

5. The wafer holding ring according to claim 4, characterized in that: It also includes a guide rail disposed in the chamber.

6. The wafer holding ring according to claim 5, characterized in that: The arched door is slidably mounted on the guide rail; The arc-shaped door is configured to be selectively opened, thereby selectively blocking the first opening end.

7. The wafer holding ring according to claim 6, characterized in that: The guide rails are arranged on both sides of the first opening end; The two arc-shaped doors are respectively mounted on guide rails on both sides of the first opening end.

8. The wafer holding ring according to claim 7, characterized in that: A spring is provided on the side of the arc-shaped door away from the first opening end; The spring is provided with elasticity between the arc-shaped door and the chamber wall; The elastic force points towards the first opening end along the guide rail direction.

9. The wafer holding ring according to claim 8, characterized in that: The pulley drive assembly includes multiple pulleys and flexible connecting parts; One end of the flexible connector is connected to the driving source; The other end of the flexible connector is connected to the arc-shaped door; The flexible connector engages with the pulley; The drive source drives the arc-shaped door to open via the pulley transmission assembly.

10. The wafer holding ring according to claim 9, characterized in that: The driving source is the telescopic rod; The telescopic rod is configured to have state one and state two; The state one includes: when the telescopic rod moves toward the first opening end, the flexible connector is stretched, the arc-shaped door moves away from the first opening end along the guide rail, and the spring is compressed; The second state includes: when the telescopic rod moves away from the first opening end, the flexible connector is released, the spring is extended, and the arc-shaped door moves along the guide rail toward the first opening end.

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