CN116175398A

CN116175398A - Chemical mechanical polishing system and polishing method

Info

Publication number: CN116175398A
Application number: CN202211702251.5A
Authority: CN
Inventors: 王剑; 路新春; 王同庆
Original assignee: Huahaiqingke Co Ltd
Current assignee: Huahaiqingke Co Ltd
Priority date: 2022-12-29
Filing date: 2022-12-29
Publication date: 2023-05-30

Abstract

The invention discloses a chemical mechanical polishing system and a polishing method, wherein the chemical mechanical polishing system comprises: a front unit; a polishing unit; the cleaning unit is arranged between the front unit and the polishing unit; the cleaning unit comprises a first cleaning unit and a second cleaning unit, the first cleaning unit and the second cleaning unit are symmetrically arranged relative to the transverse center line of the cleaning unit, a transverse transmission manipulator, a first buffer device and a second buffer device are arranged between the first cleaning unit and the second cleaning unit, and the first buffer device and the second buffer device are arranged on two sides of the transverse transmission manipulator; the first cleaning unit and the second cleaning unit comprise a post-processing module and a vertical transmission manipulator, and the post-processing module is arranged around the vertical transmission manipulator.

Description

Chemical mechanical polishing system and polishing method

Technical Field

The invention belongs to the technical field of chemical mechanical polishing, and particularly relates to a chemical mechanical polishing system and a polishing method.

Background

The integrated circuit industry is the core of the information technology industry and plays a key role in the process of converting and upgrading the boosting manufacturing industry into digital and intelligent conversion. The chip is a carrier of an integrated circuit, and the chip manufacturing involves the process flows of integrated circuit design, wafer manufacturing, wafer processing, electrical measurement, dicing packaging, testing, and the like. Among them, chemical mechanical polishing belongs to one of five main core processes in the wafer manufacturing process.

Chemical mechanical polishing (Chemical Mechanical Polishing, CMP) is a global polishing ultra-precise surface machining technique, which is one of the core processes in wafer fabrication processes. CMP systems typically include a pre-unit, a polishing unit, and a cleaning unit, which enable a wafer to be obtained that meets process requirements by chemical mechanical polishing.

Because the functions of the front unit and the polishing unit are relatively fixed, the process of the cleaning unit is complex, and the cleaning unit involves the procedures of pre-cleaning, brushing, drying and the like; the arrangement of each module in the cleaning unit is compact, so that the maintenance space of the cleaning unit is reduced, and the normal maintenance operation of operators is not facilitated.

Disclosure of Invention

The embodiment of the invention provides a chemical mechanical polishing system and a polishing method, which aim to at least solve one of the technical problems in the prior art.

In a first aspect of an embodiment of the present invention, there is provided a chemical mechanical polishing system comprising:

a front unit;

a polishing unit;

the cleaning unit is arranged between the front unit and the polishing unit;

the cleaning unit comprises a first cleaning unit and a second cleaning unit, the first cleaning unit and the second cleaning unit are symmetrically arranged relative to the transverse center line of the cleaning unit, a transverse transmission manipulator, a first buffer device and a second buffer device are arranged between the first cleaning unit and the second cleaning unit, and the first buffer device and the second buffer device are arranged on two sides of the transverse transmission manipulator; the first cleaning unit and the second cleaning unit comprise a post-processing module and a vertical transmission manipulator, and the post-processing module is arranged around the vertical transmission manipulator.

In one embodiment, the post-treatment modules are vertically stacked to form stacked modules, with the vertical transfer robot disposed between the stacked modules.

In one embodiment, the first cleaning unit and the second cleaning unit further comprise a third buffer device, and the third buffer device is disposed between the transverse transmission manipulator and the vertical transmission manipulator.

In one embodiment, the lateral transfer robot is configured with a lateral slide rail that is capable of transferring wafers between the first buffer device and the second buffer device.

In one embodiment, the first buffer device is configured with at least one buffer station; the second buffer device is provided with a plurality of buffer stations, and the buffer stations are vertically arranged at intervals.

In one embodiment, the vertical transfer robot is configured with vertical slide rails that are capable of transferring wafers between post-processing modules in the first cleaning unit or the second cleaning unit.

In one embodiment, the post-processing module includes a brush module, a pre-rinse module, and a dry module that process the wafer surface in a horizontal manner.

In one embodiment, the brush module is disposed adjacent to the polishing unit at an upper portion and/or a lower portion of the stack module.

In one embodiment, the drying module is arranged adjacent to the front unit, which is located at the upper and/or lower part of the stack module.

In one embodiment, a side of the aftertreatment module is configured with a switch door disposed toward the vertical transfer robot.

In a second aspect of embodiments of the present invention, there is provided a chemical mechanical polishing method using the chemical mechanical polishing system described above, comprising:

s1, a transverse transmission manipulator, a first buffer device and a second buffer device are combined to transmit a wafer from a front unit to a polishing unit;

s2, performing chemical mechanical polishing on the wafer by a polishing unit;

s3, combining the transverse transmission manipulator, the third buffer device and the vertical transmission manipulator, and transmitting the polished wafer to a post-processing module of the cleaning unit so as to carry out post-processing on the wafer;

and S4, if a first cleaning unit in the cleaning units fails, combining the vertical transmission manipulator, the third buffer device and the horizontal transmission manipulator, and moving the wafers with the interrupted processing to a second cleaning unit so as to continuously carry out post-processing on the wafers.

The beneficial effects of the invention include:

a. the transverse transmission manipulator, the first buffer device and the second buffer device are combined to transmit the wafer to be polished of the front unit to the polishing unit, so that the transmission efficiency is effectively improved;

b. the post-treatment modules in the cleaning unit are vertically stacked to form a stacked module, so that the space occupation is effectively reduced, and the compactness of the cleaning unit structure is improved;

c. the vertical transmission manipulator and the third buffer device are combined to realize the transmission between the post-processing modules, and the wafer after being dried can be directly transmitted to the front unit, so that the process pollution is avoided, and the effect of the post-processing of the wafer is ensured.

Drawings

The advantages of the present invention will become more apparent and more readily appreciated from the detailed description given in conjunction with the following drawings, which are meant to be illustrative only and not limiting of the scope of the invention, wherein:

FIG. 1 is a schematic diagram of a chemical mechanical polishing system provided in accordance with one embodiment of the present invention;

FIG. 2 is a front view of a chemical mechanical polishing system provided in accordance with one embodiment of the present invention;

FIG. 3 is a schematic diagram of another view of a chemical mechanical polishing system according to one embodiment of the present invention;

FIG. 4 is a transmission route diagram of a wafer in the chemical mechanical polishing system provided by the present invention;

FIG. 5 is a flow chart of a chemical mechanical polishing method according to an embodiment of the present invention.

Detailed Description

The following describes the technical scheme of the present invention in detail with reference to specific embodiments and drawings thereof. The examples described herein are specific embodiments of the present invention for illustrating the concept of the present invention; the description is intended to be illustrative and exemplary in nature and should not be construed as limiting the scope of the invention in its aspects. In addition to the embodiments described herein, those skilled in the art can adopt other obvious solutions based on the disclosure of the claims of the present application and the specification thereof, including those adopting any obvious substitutions and modifications to the embodiments described herein.

The drawings in the present specification are schematic views, which assist in explaining the concept of the present invention, and schematically show the shapes of the respective parts and their interrelationships. It should be understood that for the purpose of clearly showing the structure of various parts of embodiments of the present invention, the drawings are not drawn to the same scale and like reference numerals are used to designate like parts in the drawings.

In the present invention, "chemical mechanical polishing (Chemical Mechanical Polishing, CMP)" is also referred to as "chemical mechanical planarization (Chemical Mechanical Planarization, CMP)", and Wafer (W) is also referred to as Substrate (Substrate), the meaning and actual function are equivalent.

Embodiments of the present disclosure relate generally to Chemical Mechanical Polishing (CMP) systems used in the semiconductor device manufacturing industry. When in chemical mechanical polishing, polishing solution composed of submicron or nanometer abrasive particles and chemical solution flows between a wafer and a polishing pad, the polishing solution is uniformly distributed under the action of transmission and rotation centrifugal force of the polishing pad to form a layer of liquid film between the wafer and the polishing pad, chemical components in the liquid react with the wafer to convert insoluble substances into soluble substances, then the chemical reactants are removed from the surface of the wafer through micro-mechanical friction of the abrasive particles and dissolved in the flowing liquid to be taken away, namely surface materials are removed in the alternating process of chemical film forming and mechanical film removing to realize surface planarization treatment, so that the aim of global planarization is achieved.

FIG. 1 is a schematic diagram of a chemical mechanical polishing system according to one embodiment of the present invention, comprising:

a front unit 1, also called EFEM (Equipment Front End Module), for storing wafers to be polished and polished;

a polishing unit 3 for performing chemical mechanical polishing to accomplish material removal of the wafer surface;

the cleaning unit 2 is arranged between the front unit 1 and the polishing unit 3 to remove particles remained on the surface of the wafer in the polishing process, so as to ensure that the cleanliness of the surface of the wafer meets the process requirements.

In fig. 1, the front unit 1 includes four front opening unified pods 1a, and the front opening unified pods 1a (Front Opening Unified Pod, FOUP) are used for storing wafers. A front robot 1b is disposed at one side of the front opening unified pod 1a, and the front robot 1b is used for transferring wafers between the front unit 1 and the cleaning unit 2. The front-end robot 1b is generally configured with an upper clamping jaw and a lower clamping jaw to respectively grasp a polished wafer and a wafer to be polished, so as to avoid cross contamination during wafer clamping.

Further, the cleaning unit 2 includes a first cleaning unit 2A and a second cleaning unit 2B, and as shown in fig. 1, the first cleaning unit 2A and the second cleaning unit 2B are symmetrically disposed with respect to a lateral center line of the cleaning unit 2. A transverse transmission manipulator 4, a first buffer device 5 and a second buffer device 6 are arranged between the first cleaning unit 2A and the second cleaning unit 2B. The transverse transmission manipulator 4 is disposed along a length direction of the CMP system, and the first buffer device 5 and the second buffer device 6 are disposed on two sides of the transverse transmission manipulator 4, so that the transverse transmission manipulator 4 transmits the wafer of the first buffer device 5 to the second buffer device 6. And the second buffer means 6 is arranged next to the polishing unit 3 in order to transfer the wafer to the polishing module of the polishing unit 3 by means of a transfer mechanism.

In fig. 1, the first cleaning unit 2A and the second cleaning unit 2B include a post-processing module 7 and a vertical transfer robot 8. Wherein the post-processing modules 7 are arranged around the vertical transfer robot 8 to facilitate transfer of wafers between the respective post-processing modules 7.

Further, the lateral transfer robot 4 is provided with a lateral slide rail 41, which is capable of transferring the wafers of the first buffer device 5 to the second buffer device 6. Specifically, the lateral slide rail 41 is disposed along the length direction of the CMP system and is disposed close to the second cleaning unit 2B, so that the clamping jaws of the lateral transfer robot 4 can be located approximately at the lateral center line of the cleaning unit 2 to facilitate transfer of the wafer.

It will be appreciated that the lateral slide rail 41 may be disposed close to the first cleaning unit 2A shown in fig. 1, and the clamping jaw configured by the lateral transfer robot 4 may be disposed on the lateral center line of the cleaning unit 2.

Fig. 2 is a side view of the chemical mechanical polishing system shown in fig. 1, with the post-treatment modules 7 stacked in a vertical direction to form a stacked module. The vertical transfer robot 8 is disposed between the lamination modules to transfer the wafers between the post-processing modules 7 within the lamination modules or between the post-processing modules 7 between the lamination modules.

In some embodiments, the stacking module may also be configured with only one post-processing module 7, that is, the post-processing module 7 includes a housing and a matched electrical liquid path module, where the housing is configured with a wafer post-processing device, and the housing and the electrical liquid path module are stacked in a vertical direction, and the housing is disposed above the electrical liquid path module.

As an embodiment of the present invention, the first cleaning unit 2A further includes a third buffer device 9, and the third buffer device 9 is disposed between the lateral transfer robot 4 and the vertical transfer robot 8.

Specifically, the horizontal transfer robot 4 may place the polished wafer in the third buffer device 9, and then the vertical transfer robot 8 transfers the wafer in the third buffer device 9 to the post-processing module 7 in the first cleaning unit 2A, so as to complete the post-processing of the wafer.

In the present invention, the third buffer device 9 is provided with at least one buffer station. In some embodiments, the third buffer device may be configured with a plurality of buffer stations, where the buffer stations are stacked in a vertical direction, so as to buffer a small number of wafers stacked due to unequal process times between modules.

Fig. 3 is a schematic diagram of a cleaning unit according to an embodiment of the present invention, in which a first buffer device 5 is configured with a buffer station for placing a wafer to be processed. That is, the pre-robot 1b (shown in fig. 1) in the pre-unit 1 may previously place the wafer in the first buffer device 5 so that the lateral transfer robot 4 clamps the wafer to transfer toward the polishing unit.

It can be appreciated that the first buffer device 5 may also be configured with a plurality of buffer stations, where the buffer stations may be disposed along a vertical direction, so as to reduce space occupation and improve compactness of the configuration inside the cleaning unit.

Further, the second buffer device 6 is configured with a plurality of buffer stations, and the buffer stations are vertically spaced to respectively store the wafer to be polished and the wafer after polishing. The wafer to be polished is generated to a polishing module by the aid of a manipulator in the polishing unit 3, the polished wafer is transferred to the third buffer device 9 in advance by the transverse transfer manipulator 4, and then the wafer on the third buffer device 9 is transferred to the post-processing module 7 in the cleaning unit 2 by the vertical transfer manipulator 8.

In fig. 3, the vertical transfer robot 8 is provided with a vertical slide rail 81, and a clamping jaw provided thereon is slidably connected to the vertical slide rail 81. The clamping jaws can be moved in a vertical direction in order to transfer wafers between the stacked post-processing modules 7.

Specifically, the vertical slide rail 81 is provided on the frame of the cleaning unit 2, and, between the adjacent stacked modules, the holding claws are provided toward the inside of the cleaning unit 2 so as to transfer the wafer between the post-processing modules 7 in the first cleaning unit 2A or the second cleaning unit 2B.

In the embodiment shown in fig. 1, the post-processing module 7 includes a brushing module, a pre-cleaning module, and a drying module, which support the wafer in a horizontal manner to remove residual particles and chemicals on the surface of the wafer and obtain a clean surface wafer.

As one embodiment of the present invention, the brush module is provided with a housing, and a support roller is provided inside the housing to horizontally support a wafer to be processed. Under the action of friction force between the supporting roller and the edge of the wafer, the wafer rotates around the central axis, the cleaning brush and the liquid supply part are arranged on the front surface and the back surface of the wafer, the cleaning brush rotates around the axis, and meanwhile, the liquid supply part supplies cleaning liquid to the cleaning brush and/or the surface of the wafer so as to remove larger-volume particles on the surface of the wafer and realize rough cleaning of the wafer.

In fig. 1, a brush module in the post-treatment module 7 may be provided adjacent to the polishing unit 3, and the brush module may be located at an upper portion and/or a lower portion of the stack module.

Further, the pre-cleaning module is provided with a housing, a plurality of claws are arranged in the housing, and the wafer is horizontally clamped by the plurality of claws and is driven to rotate by a rotary driving device which is not shown. Further, the pre-cleaning module comprises a double-fluid pipe and a cleaning head, wherein the double-fluid pipe sprays cleaning liquid, N2 and/or deionized water towards the wafer so as to remove particles with smaller surfaces of the wafer, and fine cleaning of the wafer is realized; the brush head is arranged above the wafer through a swing arm, and the swing arm can swing around a fixed point so as to drive the brush head to move on the surface of the wafer to clean tiny particles on the surface of the wafer.

In the drying module, the wafer is horizontally clamped by the clamping jaws and driven to rotate at a high speed, and a drying mechanism, not shown, such as a marangoni drying mechanism, is arranged above the wafer to integrally strip a water film on the surface of the wafer, so that the wafer is dried.

In the embodiment shown in fig. 1, the drying modules configured by the first cleaning unit 2A and the second cleaning unit 2B need to be horizontally adjacent to the front unit 1, so that the front robot 1B in the front unit 1 can directly place the dried wafers in the front open type wafer transfer box 1a, thereby reducing the turnover transmission times of the wafers and avoiding pollution in the transmission process.

In fig. 1, the drying module is located at the upper part of the lamination module, i.e. the post-processing module located at the upper part of the lamination module is the drying module. This is because the drying module needs to be provided with a Fan Filter Unit (FFU) that circulates the supplied drying gas. If the drying module is disposed at the post-processing module corresponding to the lower part of the stacking module, the fan filter unit occupies a certain space, i.e., the vertical height of the cleaning unit 2 is increased.

It will be appreciated that the drying module may be placed in the lower portion of the stack module if the vertical height of the cmp system is not limited.

In order to facilitate the transfer of wafers, the side of the post-processing module 7 is provided with a switch door, which is arranged towards the vertical transfer robot 8.

It should be noted that, the housing of the drying module in the post-processing module 7 needs to be provided with one more switch door, and the switch door is provided toward the front unit 1, so that the front robot 1b directly transfers the wafers in the drying module into the front opening unified pod 1a.

In the invention, the first cleaning unit 2A and the second cleaning unit 2B operate independently, namely, one of the cleaning units fails to stop, the operation of the other cleaning unit is not influenced, and the fault tolerance of the chemical mechanical polishing system is effectively improved.

As an embodiment of the present invention, the drying module in the post-processing module 7 needs to be disposed adjacent to the pre-unit 1, and other modules of the post-processing module 7 may be freely matched according to the wafer process requirement.

Fig. 4 is a corresponding wafer transfer path diagram during operation of the cmp system, and the general transfer of wafers between the head unit 1, the cleaning unit 2, and the polishing unit 3 will be described in brief with reference to fig. 4. The transfer path of the wafer from the front unit 1 to the polishing unit 3 is indicated by a chain line.

Firstly, a front manipulator 1b in a front unit 1 transfers wafers of a front opening wafer transfer box 1a to a first buffer device 5; next, the transverse transfer robot 4 transfers the wafer on the first buffer device 5 to the second buffer device 6 to perform chemical mechanical polishing on the unit to be polished 3.

After the polishing unit 3 finishes polishing treatment on the wafer, a manipulator in the polishing unit 3 places the polished wafer in the second buffer device 6; next, the transverse transfer robot 4 transfers the polished wafer to the third buffer device 9; then, the vertical transmission manipulator 8 transmits the wafer placed by the third buffer device 9 to the post-processing module 7 in the cleaning unit 2 so as to complete the cleaning and drying treatment of the wafer; after the wafer is dried, the front robot 1b directly transfers the dried wafer to the front opening unified pod 1a.

In addition, the invention also provides a chemical mechanical polishing method, and a flow chart of the chemical mechanical polishing method is shown in fig. 5. The method is performed on the chemical mechanical polishing system described above, and the steps of the polishing method are described below in connection with the embodiment shown in fig. 1, which includes:

s1, a transverse transmission manipulator 4, a first buffer device 5 and a second buffer device 6 are combined to transmit a wafer from a front unit 1 to a polishing unit 3;

s2, the polishing unit 3 performs chemical mechanical polishing on the wafer;

s3, combining the transverse transmission manipulator 4, the third buffer device 9 and the vertical transmission manipulator 8, and transmitting the polished wafer to a post-processing module 7 of the cleaning unit 2 so as to carry out post-processing on the wafer;

s4, if the first cleaning unit 2A in the cleaning units 2 fails, the vertical transmission manipulator 8, the third buffer device 9 and the horizontal transmission manipulator 4 are combined to move the wafer with the interrupted processing to the second cleaning unit 2B so as to continuously carry out post-processing on the wafer.

That is, the first cleaning unit 2A and the second cleaning unit 2B in the cleaning units 2 are independent from each other, and if one unit module fails, the wafers with the process interruption can be transferred to the unit module with the normal operation, so as to avoid the influence of manual wafer taking on the wafer processing efficiency.

In step S4, the vertical transfer robot 8 in the first cleaning unit 2A may transfer the wafers subjected to the interrupt process to the third buffer device 9, then the horizontal transfer robot 4 transfers the wafers placed in the third buffer device 9 in the first cleaning unit 2A to the third buffer device 9 in the second cleaning unit 2B, and then the vertical transfer robot 8 in the second cleaning unit 2B clamps the wafers of the third buffer device 9 to continue to perform the cleaning and drying process on the wafers.

As a variant of this embodiment, the wafers may be transferred from the first cleaning unit 2A to the second cleaning unit 2B by means of the transverse transfer robot, the first buffer device 5 and/or the second buffer device 6, so as to continuously perform post-processing on the interrupted wafers, remove particles and water films on the surfaces of the wafers, and realize dry in/dry out of the wafers.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A chemical mechanical polishing system comprising:

a front unit;

a polishing unit;

the cleaning unit is arranged between the front unit and the polishing unit;

2. The chemical mechanical polishing system of claim 1 wherein the post-processing modules are vertically stacked to form stacked modules, the vertical transfer robot being disposed between the stacked modules.

3. The chemical mechanical polishing system of claim 1, wherein the first cleaning unit and the second cleaning unit further comprise a third buffer device disposed between the lateral transfer robot and the vertical transfer robot.

4. The chemical mechanical polishing system of claim 1, wherein the lateral transfer robot is configured with a lateral slide rail capable of transferring wafers between the first buffer and the second buffer.

5. The chemical mechanical polishing system of claim 1 wherein the first buffer is configured with at least one buffer station; the second buffer device is provided with a plurality of buffer stations, and the buffer stations are vertically arranged at intervals.

6. The chemical mechanical polishing system of claim 1, wherein the vertical transport robot is configured with a vertical slide rail capable of transporting wafers between post-processing modules in the first cleaning unit or the second cleaning unit.

7. The chemical mechanical polishing system of claim 2, wherein the post-processing module comprises a brush module, a pre-rinse module, and a dry module that process the wafer surface in a horizontal manner.

8. The chemical mechanical polishing system of claim 7, wherein the brush module is disposed adjacent to the polishing unit at an upper portion and/or a lower portion of the stack module.

9. A chemical mechanical polishing system according to claim 7, wherein the drying module is disposed adjacent to the head unit at an upper portion and/or a lower portion of the stack module.

10. The chemical mechanical polishing system of claim 1, wherein a side of the post-processing module is configured with an opening and closing door disposed toward the vertical transfer robot.

11. A chemical mechanical polishing method, characterized by using the chemical mechanical polishing system according to any one of claims 1 to 10, comprising:

s2, performing chemical mechanical polishing on the wafer by a polishing unit;