CN116061083A

CN116061083A - Chemical mechanical polishing device and polishing method

Info

Publication number: CN116061083A
Application number: CN202111269300.6A
Authority: CN
Inventors: 赵德文
Original assignee: Huahaiqingke Co Ltd
Current assignee: Huahaiqingke Co Ltd
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2023-05-05

Abstract

The invention discloses a chemical mechanical polishing device and a polishing method, wherein the chemical mechanical polishing device comprises a polishing disk; the bearing head is used for receiving and loading the wafer on the polishing pad at the upper part of the polishing disc; the top surface of the polishing disk is provided with a groove, the groove and the polishing pad form a sealing cavity, and the pressure adjusting part is communicated with the sealing cavity to adjust the pressure of the cavity so as to deform the polishing pad on the upper side of the groove; so that the carrier head can rotate and move along the radial direction of the polishing pad to control the horizontal distance between the wafer and the grooves and adjust the removal rate of the edge part of the wafer.

Description

Chemical mechanical polishing device and polishing method

Technical Field

The invention belongs to the technical field of chemical mechanical polishing, and particularly relates to a chemical mechanical polishing device 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 technological processes of chip design, wafer manufacturing, wafer processing, electrical measurement, dicing packaging, testing, and the like. Wherein the chemical mechanical polishing belongs to the wafer manufacturing process.

Chemical mechanical polishing (Chemical Mechanical Planarization, CMP) is a globally planarized ultra-precise surface finish technique. Chemical mechanical polishing typically pulls a wafer against the bottom surface of a carrier head, the surface of the wafer with the deposited layer being pressed against the upper surface of the polishing pad, the carrier head rotating in the same direction as the polishing pad under the actuation of a drive assembly and imparting a downward load to the wafer; meanwhile, the polishing solution is supplied to the upper surface of the polishing pad and distributed between the wafer and the polishing pad, so that the wafer is subjected to chemical mechanical polishing under the combined action of chemistry and machinery.

When chemical polishing is performed, the polishing rate of the edge portion of the wafer is greater than that of the center portion of the wafer, which may result in deterioration of polishing uniformity of the wafer. Particularly, in some wafer processes, local thinning treatment is performed on certain areas of the wafer, which puts higher requirements on global planarization of the wafer, and how to control polishing rates of different areas of the wafer, so as to realize global planarization of the wafer is always a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art to a certain extent.

To this end, a first aspect of an embodiment of the present invention provides a chemical mechanical polishing apparatus, comprising:

polishing disk;

the bearing head is used for receiving and loading the wafer on the polishing pad at the upper part of the polishing disc;

the top surface of the polishing disk is provided with a groove, the groove and the polishing pad form a sealing cavity, and the pressure adjusting part is communicated with the sealing cavity to adjust the pressure of the cavity so as to deform the polishing pad on the upper side of the groove;

so that the carrier head can rotate and move along the radial direction of the polishing pad to control the horizontal distance between the wafer and the grooves and adjust the removal rate of the edge part of the wafer.

As a preferred embodiment, the pressure regulating part is communicated with the sealing cavity through a pipeline, and the pressure regulating part comprises a gas source and a regulating valve, and the gas source and the regulating valve are used for evacuating or ventilating the sealing cavity so as to regulate the pressure of the sealing cavity.

As a preferred embodiment, when the sealing cavity is under negative pressure, the polishing pad on the upper side of the groove deforms toward the lower side, so that the rebound height of the polishing pad on the upper side of the groove is reduced in a pressed state.

As a preferred embodiment, the bottom of the groove is provided with a plurality of connecting holes which are uniformly distributed along the circumference; the pressure regulating part is communicated with the connecting hole through the main pipeline and the branch pipeline so as to evacuate or ventilate the sealing cavity.

As a preferred embodiment, the main pipeline is concentrically arranged at the lower part of the polishing disk, and the branch pipeline is arranged between the main pipeline and the connecting hole and is radially distributed with the main pipeline as a center.

As a preferred embodiment, the groove is an annular structure, and is concentrically disposed on the top surface of the polishing disk.

As a preferred embodiment, the polishing device further comprises an adjusting piece, which is arranged in the groove of the polishing disk; the regulating member extends to the top surface of the polishing disk toward the upper side.

A second aspect of an embodiment of the present invention provides a chemical mechanical polishing method using the chemical mechanical polishing apparatus described above, comprising the steps of:

a carrier head that receives the wafer rotates and loads the wafer to the rotating polishing pad;

performing chemical mechanical polishing according to a polishing process and detecting the surface morphology of the wafer;

the pressure adjusting part adjusts the pressure of a sealing cavity formed by the groove and the polishing pad, so that the polishing pad on the upper side of the groove deforms towards the lower side;

the horizontal distance of the wafer relative to the groove is controlled according to the wafer surface morphology and the material removal rate profile to adjust the removal rate of the wafer edge portion.

As a preferred embodiment, the wafer is controlled to move toward the recess when the removal rate of the wafer edge is higher than the set removal rate.

As a preferred embodiment, the wafer is moved over the surface of the polishing pad, and the outer edge of the wafer is moved within 1/2 of the width of the recess.

The beneficial effects of the invention include: an annular groove is formed in the top of the polishing disc, and a pressure adjusting part is arranged on the groove to adjust the pressure of a sealing cavity formed by the groove and the polishing pad on the upper part, so that the polishing pad on the upper side of the groove is deformed; the polishing pad on the upper side of the groove is provided with a region with low rebound height, the horizontal position of the wafer and the polishing time at the position are determined according to the surface appearance of the wafer and the contour line of the material removal rate, and the material removal amount of the edge part of the wafer is regulated to realize the global planarization of the wafer.

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 view of a chemical mechanical polishing apparatus 100 according to the present invention;

FIG. 2 is a schematic view of the structure of the carrier head 30 according to the present invention;

figure 3 is a schematic view of a polishing pad 10 of the present invention configured with a polishing pad 20;

FIG. 4 is a top view corresponding to FIG. 3;

FIG. 5 (a) is a schematic view of the rounded edges of the grooves of the present invention and a deformation trend of the polishing pad thereon;

FIG. 5 (b) is a schematic view of the placement of the right angle at the edges of the grooves and the deformation trend of the polishing pad thereon according to the present invention;

FIG. 5 (c) is a schematic view of the cross-section of the groove of the present invention in a trapezoid shape and a deformation trend of the polishing pad thereon;

FIG. 6 is a schematic view of the internal configuration of the grooves and a deformation trend of the polishing pad thereon according to the present invention;

FIG. 7 is a schematic view of another embodiment of a chemical mechanical polishing apparatus 100 according to the present invention;

FIG. 8 is a schematic view of a connection hole in a groove according to the present invention;

FIG. 9 is a schematic representation of the deformation of the polishing pad after inflation of the seal chamber 10C in accordance with the present invention;

FIG. 10 (a) is a prior art deformation of a polishing pad of a wafer edge portion when a wafer W is pressed against the polishing pad;

FIG. 10 (b) shows the deformation of the polishing pad at the edge portion of the wafer W when the wafer W is pressed against the polishing pad according to the present invention;

FIG. 11 is a material removal rate profile of an edge portion of a wafer in accordance with the present invention;

fig. 12 is a prior art material removal rate profile corresponding to 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 of which are equivalent; material removal rate (Material Remove Rate, MRR); the wafer edge portion may also be referred to as a wafer edge.

Fig. 1 is a schematic view of a chemical mechanical polishing apparatus according to the present invention, wherein a chemical mechanical polishing apparatus 100 includes a polishing platen 10, a polishing pad 20, a carrier head 30, a conditioner 40, and a liquid supply portion 50; the polishing pad 20 is provided on the upper surface of the polishing disk 10 and rotates together therewith along the axis Ax; a horizontally movable carrier head 30 disposed above the polishing pad 20, the lower surface of which receives a wafer to be polished; the dresser 40 includes a dressing arm and a dressing head, which are provided on one side of the polishing disk 10, the dressing arm driving the rotating dressing head to swing to dress the surface of the polishing pad 20; the liquid supply part 50 is disposed at an upper side of the polishing pad 20 to spread the polishing liquid on the surface of the polishing pad 20.

During polishing operation, the carrier head 30 presses the surface to be polished of the wafer against the surface of the polishing pad 20, and the carrier head 30 performs rotary motion and reciprocating motion along the radial direction of the polishing disk 10 so that the surface of the wafer contacted with the polishing pad 20 is gradually polished; simultaneously, the polishing disk 10 rotates, and the liquid supply part 50 sprays the polishing liquid onto the surface of the polishing pad 20. The wafer is rubbed against the polishing pad 20 by the relative motion of the carrier head 30 and the polishing platen 10 under the chemical action of the polishing liquid to perform polishing.

The polishing solution composed of submicron or nanometer abrasive particles and chemical solution flows between the wafer and the polishing pad 20, the polishing solution is uniformly distributed under the action of the transmission and rotation centrifugal force of the polishing pad 20 to form a layer of liquid film between the wafer and the polishing pad 20, 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 the micro-mechanical friction of the abrasive particles and dissolved into the flowing liquid to be taken away, namely, surface materials are removed in the alternating process of chemical film formation and mechanical film removal to realize surface planarization treatment, so that the aim of global planarization is achieved.

The conditioner 40 is used to condition and activate the surface topography of the polishing pad 20 during chemical mechanical polishing. The use of the dresser 40 can remove impurity particles remaining on the surface of the polishing pad, such as abrasive particles in the polishing liquid, and waste material falling off from the wafer surface, and can planarize the deformation of the surface of the polishing pad 20 due to the polishing, ensuring the uniformity of the surface topography of the polishing pad 20 during polishing, and further maintaining a stable polishing removal rate.

To improve the integration level, the feature line width of the logic chip has been reduced to below 10nm, such as 7nm, 5nm, and even 3nm; the number of stacked layers of memory chips has also progressed from 64 layers to 128 layers or more. The improvement of chip integration level puts higher demands on polishing uniformity.

To meet polishing uniformity requirements, chemical mechanical polishing is currently performed using a multi-chamber carrier head, shown schematically in FIG. 2 as carrier head 30. The carrier head 30 is configured with an elastic membrane having a plurality of chambers to precisely adjust the polishing pressure of each portion of the wafer, control the material removal amount of the wafer, and achieve global planarization. In fig. 2, the carrier head 30 is configured with 5 chambers, and it is understood that the number of chambers of the elastic membrane may be 3, 6, 7, 9, etc.

However, the linear velocity of the edge portion of the wafer is greater than that of the center of the wafer during polishing, and the edge portion of the wafer is more likely to contact the polishing liquid, so that the removal rate of the edge portion of the wafer is greater than that of the center of the wafer. In addition, due to the superposition effect of the adjacent chambers, the pressure regulation capability of the edge part of the wafer is improved only by adding the chambers of the edge part of the elastic film, the difficulty of pressure regulation is increased intangibly, and the removal rate of the edge part of the wafer can not be controlled accurately.

Aiming at the technical problems, the invention starts from the polishing pad, controls the rebound height of the polishing pad under the pressed state, improves the pressure regulating and controlling capability of the edge part of the wafer, and improves the polishing uniformity of the wafer.

The polishing disk 10 of the present invention is provided with a polishing pad 20 on its top surface as shown in fig. 3 in a cross-sectional view. The polishing disk 10 is provided with a groove 10a on the top surface, and the groove 10a is of an annular structure and is arranged concentrically with the polishing disk 10. Fig. 4 is a top view of the polishing pad 10 shown in fig. 3.

As an embodiment of the present invention, at least one of the number of grooves 10a may be provided near the edge of the polishing pad 10, as shown in fig. 3. It will be appreciated that the grooves 10a may also be located near the center of the polishing pad 10. As a variation of the present invention, the top surface of the polishing pad 10 may be provided with two grooves 10a, one groove 10a being provided near the edge position of the polishing pad 10 and the other groove 10a being provided near the center position of the polishing pad 10.

In the embodiment shown in fig. 4, the number of grooves 10a is one, which is provided near the edge position of the polishing pad 10. In fig. 4, the grooves 10a are 120mm from the edge of the polishing pad 10. The position of the groove 10a can be flexibly configured according to the polishing process of the wafer, and the distance between the groove 10a and the edge position of the polishing disk 10 can be 10mm-150mm. In fig. 4, the width of the groove 10a is 15mm, and it is understood that the width of the groove 10a is about to cover the edge position of the wafer and the acting position of the retaining ring of the carrier head 30, and the width of the groove 10a may be greater than 5mm and not greater than 30mm.

In fig. 3, the tendency of the polishing pad 10 on the upper side of the groove 10a to deform in a pressed state is indicated by a broken line. The exaggerated technique used in the figures shows the tendency of the polishing pad 10 to deform. In chemical mechanical polishing, the deformation of the polishing pad is about 10 μm.

The arrangement of the grooves 10a effectively improves the stress distribution of the polishing pad 20 under the pressed state, reduces or eliminates the rebound height of the polishing pad 20, is beneficial to reducing the reaction force of the polishing pad 20 to the wafer, improves the stress concentration of the edge part of the wafer, improves the pressure control capability of the edge part of the wafer, and balances the removal rates of the edge part and the central part of the wafer. I.e., the horizontal position of the wafer with respect to the recess 10a is controlled so that the wafer is moved to a region where the rebound height of the polishing pad is moderate, to adjust the removal rate of the edge portion of the wafer.

It will be appreciated that the grooves 10a may also be of non-annular configuration, such as an array of grooves along the top surface of the polishing platen 10, with a circular, rectangular or triangular cross-section, etc., to control the rebound height of localized areas of the polishing pad 20 mounted on the upper portion of the platen 10, and to assist in controlling the wafer polishing removal rate.

In order to further optimize the stress distribution of the polishing pad 20 on the upper side of the groove 10a and improve the rebound height of the polishing pad in a pressed state, the top edge of the groove 10a is provided with a rounded corner or chamfer, as shown in fig. 5 (a) and 5 (b). In fig. 5 (a), the top edge of the groove 10a is provided with rounded corners; in fig. 5 (b), the top edge of the groove 10a is provided with a chamfer. The arrangement of the round corners or the chamfers reduces the rebound height of the wafer edge part corresponding to the polishing pad by 30% -50%, which is beneficial to improving the pressure control capability of the wafer edge part.

As another embodiment of the present invention, the cross section of the groove 10a is trapezoidal, and the upper width of the groove 10a is larger than the lower width thereof, as shown in fig. 5 (c). The provision of the grooves 10a enables optimization of the stress distribution of the polishing pad 20 in a pressed state on the upper side of the grooves 10a so that the polishing pad has a region of reduced rebound height in a localized region. The material removal amount of the wafer edge portion can be controlled by controlling the horizontal position of the wafer so that the wafer edge portion contacts the region of the polishing pad having a lower rebound height.

Figure 6 is a schematic view of another embodiment of a groove 10a corresponding to the polishing disk 10 according to the present invention. The chemical mechanical polishing apparatus further includes an adjusting member 60 disposed in the recess 10 a; the top surface of the protruding portion 60a of the regulating member 60 is flush with the top surface of the polishing pad 10.

As one aspect of this embodiment, the modulus of elasticity of the conditioning element 60 is less than the modulus of elasticity of the polishing pad 10. Preferably, the regulator 60 is made of polyurethane. It will be appreciated that the conditioning element 60 may also be formed from other non-metallic and/or metallic materials having a modulus of elasticity that is lower than the modulus of elasticity of the polishing pad 10. Preferably, the regulator 60 is selected from a non-metallic material such as polytetrafluoroethylene. The polishing disk 60 is generally made of a metal material, and the adjusting piece 60 is made of a non-metal material, so that mutual friction or ion diffusion and mutual adhesion caused by vibration between metals are effectively avoided, and metal ion pollution generated by a chemical mechanical polishing device is avoided.

As an aspect of this embodiment, the top surface of the protruding portion 60a may be slightly lower than the top surface of the polishing pad 10, for example, the difference in height between the two is 3mm to 5mm, so as to control the rebound deformation of the polishing pad on the upper side of the groove 10a in a pressed state.

As another aspect of this embodiment, the width of the projection 60a is 1/10-1/5 of the width of the recess 10 a. The width of the protruding portion 60a is related to its elastic modulus, and the width of the protruding portion 60a can be flexibly determined according to the material of the regulating member 60.

Fig. 5 (a), 5 (b) and 5 (c) are views of the structure of the groove 10a, which improve the rebound height of the polishing pad 20 under compression on the upper side of the groove 10a, and weaken the stress concentration of the polishing pad 20. It is to be understood that the chemical mechanical polishing apparatus 100 may be provided with a pressure adjusting portion 70, and the pressure of the seal chamber 10C formed by the groove 10a and the upper polishing pad 20 may be changed by the pressure adjusting portion 70, as shown in fig. 7, so as to weaken the stress concentration of the polishing pad 20 in a pressed state.

In the embodiment shown in fig. 7, the pressure adjusting part 70 is communicated with the seal chamber 10C through a pipe and a rotary joint 10b provided at the lower part of the polishing disk 10, and evacuates the seal chamber 10C by a vacuum source or introduces air into the seal chamber 10C by an air source to adjust the pressure of the seal chamber 10C.

As an aspect of the present embodiment, the pressure regulating portion 70 discharges the gas of the seal chamber 10C through the vacuum source to make the seal chamber 10C form a negative pressure; alternatively, the seal chamber 10C is not inflated and its pressure gradually decreases; due to the evacuation, the polishing pad 20 on the upper side of the groove 10a is deformed toward the lower side, and the polishing pad 20 on the upper side of the groove 10a comes to have a region of low rebound height shown in fig. 5 (a), 5 (b) and 5 (c) in a pressed state. The horizontal position of the wafer with respect to the grooves 10a is changed so that the edge portion of the wafer overlaps with the region of low rebound height of the polishing pad 20 to adjust the removal rate of the edge portion of the wafer and promote the uniformity of the wafer polishing.

In order to improve the adhesive strength of the polishing pad 20 and the polishing pad 10 at the groove 10a, the top surface of the polishing pad 10 corresponding to the outer peripheral side of the groove 10a may be roughened to increase the roughness of this area. The texturing zone may be provided as an annular face which is arranged concentrically with the groove 10 a. As an embodiment of the present invention, the roughened area on the top surface of the polishing disk 10 may be provided with no non-metal coating, and other areas are normally coated with a non-metal coating such as polytetrafluoroethylene, so as to ensure the reliability of the adhesion of the polishing pad 20 to the polishing disk 10 without affecting the convenience of replacement and detachment of the polishing pad.

It will be appreciated that the greater the negative pressure created by the sealed chamber 10C, the greater the downward-facing deformation of the polishing pad 20. The pressure of the sealing cavity 10C and the horizontal position of the wafer are regulated, so that the edge part of the wafer is overlapped with the area with moderate rebound height of the polishing pad, and the control of the material removal rate of the edge part of the wafer is realized.

The pressure of the seal chamber 10C is set to 0.1psi-2psi, it being understood that the pressure of the seal chamber 10C is related to the useful life of the polishing pad 20, and thus the pressure of the seal chamber 10C needs to be flexibly set according to the useful life of the polishing pad 20. In the initial stage of use of the polishing pad 20, the performance of the polishing pad 20 is stable, and the pressure of the seal cavity 10C can be set higher; at the end of the use of the polishing pad 20, the performance of the polishing pad 20 is degraded and the pressure of the seal chamber 10C can be set lower.

As an embodiment of the present invention, the gas may be introduced into the seal chamber 10C through the gas source of the pressure adjusting portion 70 to change the pressure of the seal chamber 10C. I.e., the seal chamber 10C is inflated and deformed toward the upper side to increase the rebound height of the upper side polishing pad 20 of the recess 10a, and to increase the removal rate of this area to balance the material removal rate of the respective portions of the wafer.

In order to ensure uniform contraction or expansion of the seal chamber 10C, a plurality of junctions need to be provided for the groove 10 a. In fig. 8, a plurality of connection holes 10d are provided at the bottom of the groove 10a, and the connection holes 10d are uniformly distributed along the circumference to ensure uniformity of pressure variation of the sealing chamber 10C. In the embodiment shown in fig. 8, the connection hole 10d is located at an intermediate position of the bottom of the recess 10 a. When the groove 10a is provided at the edge position of the polishing pad 10, the coupling hole 10d may be provided near the inner sidewall of the groove 10a so as to rapidly adjust the rebound height of the polishing pad corresponding to the edge position of the wafer. The number of the connecting holes 10d is 4, and it is understood that the number of the connecting holes 10d may be other numbers, such as 8, 12, 16, etc.

Further, the pressure adjusting portion 70 communicates with the connection holes 10d through the main pipe 81 and the branch pipe 82, the number of the branch pipes 82 matches the number of the connection holes 10d, and the branch pipes 82 are arranged in a radial shape to connect the main pipe 81 and the connection holes 10d. The main pipe 81 is disposed at an intermediate position of the lower portion of the polishing platen 10, and fluid can enter the seal chamber 10C through the main pipe 81, the branch pipe 82, and the connection hole 10d.

Fig. 9 is a schematic view showing the deformation of the polishing pad 20 after the inflation of the seal chamber 10C, wherein the broken line indicates that the polishing pad 20 is deformed after the ventilation of the seal chamber 10C, and the rebound height of the polishing pad 20 is increased. By changing the horizontal position of the wafer relative to the recess 10a, a certain portion of the wafer is brought into contact with the region to increase the material removal rate of the contact region, equalizing the global material removal rate of the wafer.

Fig. 10 (a) shows a tendency of the polishing pad to deform at an edge portion of the wafer W when the wafer W is pressed against the polishing pad 20 in the related art, and the deformation of the polishing pad 20 at this portion is indicated by a broken line. Since the polishing pad 20 has a rebound phenomenon, the polishing pad 20 bulges at the wafer edge portion, thereby affecting the polishing pressure control at that portion.

In contrast, fig. 10 (b) shows the deformation of the polishing pad at the edge portion of the wafer W when the wafer W is pressed against the polishing pad 20 in the present invention. Since the grooves 10a are provided on the top surface of the polishing pad 10, the stress distribution of the polishing pad 20 on the upper side of the grooves 10a is optimized, and the bulge of the wafer edge portion becomes low or moves forward, thereby improving the pressure control capability of the wafer edge portion.

Further, a second aspect of the present invention provides a chemical mechanical polishing method using the chemical mechanical polishing apparatus described above, comprising the steps of:

s1: the carrier head 30, which receives the wafer, rotates and loads the wafer to the rotating polishing pad 20;

specifically, the elastic membrane of the carrier head 30 attracts the wafer to be polished to the lower part of the carrier head 30, the carrier head 30 moves horizontally to the polishing pad 20, and the carrier head 30 and the polishing pad 20 rotate in the same direction and maintain a certain speed difference; the carrier head 30 presses the surface to be polished of the wafer against the surface of the polishing pad 20, and the carrier head 30 makes a rotational motion and reciprocates in the radial direction of the polishing disk 10 so that the surface of the wafer in contact with the polishing pad 20 is gradually polished.

S2: performing chemical mechanical polishing according to a polishing process and detecting the surface morphology of the wafer;

and (3) intelligently adjusting the pressure of each cavity of the elastic film to polish the wafer according to the polishing process, and detecting the surface morphology of the wafer to obtain the material removal information of each part of the wafer. Specifically, a Recipe for chemical mechanical polishing is formulated according to the polishing process, and the material removal amount of each portion of the wafer is controlled.

S3: the pressure adjusting part adjusts the pressure of a sealing cavity formed by the groove and the polishing pad, so that the polishing pad on the upper side of the groove deforms towards the lower side;

depending on the life of the polishing pad 20, the pressure of the seal chamber 10C formed by the grooves 10a and the polishing pad 20 is adjusted so that the polishing pad 20 on the upper side of the grooves 10a deforms toward the lower side to create an area where the rebound height of the polishing pad 20 decreases.

S4: the horizontal distance of the wafer relative to the recess 10a is controlled according to the wafer surface topography and the material removal rate profile to adjust the removal rate of the wafer edge portion.

As one embodiment of the present invention, when the removal rate of the wafer edge is higher than the set removal rate, it is necessary to control the movement of the wafer toward the recess. Specifically, the wafer is moved on the surface of the polishing pad, and the outer edge of the wafer is moved within 1/2 of the width of the groove 10a, so as to prevent the removal rate of the edge of the wafer from fluctuating too much to affect the uniformity of the wafer polishing.

Specifically, the material removal rate profile is a material removal rate profile obtained when the wafer is at different horizontal positions relative to the groove, and is stored in a storage module of the control part.

Because of certain differences in the working conditions of the cmp apparatus, such as polishing pad, polishing liquid, carrier head, and conditioner, a test wafer is required to collect the material removal rate profile applicable to the current cmp apparatus during cmp. It will be appreciated that the material removal rate profile may be obtained off-line or on-line. Since the thickness acquisition error of the wafer edge portion is large in the on-line inspection, it is recommended to measure the film thickness of the wafer in an off-line manner when calculating the material removal rate profile.

Fig. 11 shows material removal rate profiles for corresponding wafer edge portions of a wafer at different horizontal positions. The horizontal distance of the wafer with respect to the recess 10a is denoted by L as shown in fig. 4. The position where the wafer edge coincides with the side of the groove 10a near the center of the polishing pad 20 is set as a zero point, the direction of the zero point toward the center of the polishing pad 20 is set as a positive direction, that is, the horizontal position between the wafer edge and the center of the polishing pad 20 is positive, and the horizontal position between the zero point and the edge position of the polishing pad 20 is negative.

During chemical mechanical polishing, the control part determines the horizontal position of the wafer and the polishing time at the position according to the surface morphology and the material removal rate contour line of the wafer so as to adjust the material removal amount of the edge part of the wafer and even the material removal rate of the central part of the wafer and the edge part of the wafer, thereby realizing the global planarization of the wafer.

In fig. 11, when l=10 mm, l=20 mm, and l=30 mm, the material removal rate profile line of the wafer edge portion has a valley at a position of about 145 mm; the valley value of the material removal rate contour line corresponding to l=10mm is higher than the valley value corresponding to the other two positions, namely, the material removal rate of the position of the wafer about 145mm is higher than the material removal rate of the position close to the center of the wafer; and at a position between 145mm and 150mm, the removal rate of the material is reduced to the extreme value corresponding to the removal rate, which is advantageous for polishing uniformity.

And the material removal rate contour line corresponding to L= -10mm is positioned at the lower side of the material removal rate contour line corresponding to other positions, so that a proper position exists between-10 mm and 20mm in the horizontal position of the wafer, and the material removal rates of the central part and the edge part of the wafer can be balanced. The control section controls the movement of the carrier head 30 to change the horizontal position of the wafer, and can reduce the amount of material removed from the edge portion of the wafer.

Fig. 12 is a material removal rate profile corresponding to the present invention in the prior art, wherein the solid line is a material removal profile corresponding to the prior art, and the removal rate of the edge portion of the wafer is greater than the removal rate of the center portion of the wafer because the linear velocity of the edge portion of the wafer is greater than the linear velocity of the center portion of the wafer during wafer polishing and the edge portion of the wafer is more easily combined with the polishing liquid. In fig. 12, a dashed line is used to indicate a contour line of a material removal rate corresponding to the cmp method according to the present invention, since the top surface of the polishing disk 10 is provided with the groove 10a, the stress distribution of the polishing pad 20 at the groove 10a is optimized, the rebound height of the polishing pad 20 in a pressed state is reduced or eliminated, the horizontal position of the wafer is controlled, so that the edge portion of the wafer contacts with a position with a moderate rebound height and cmp is performed, the pressure regulation capability of the edge portion of the wafer is effectively improved, the removal rates of the middle portion and the edge portion of the wafer are balanced, and global planarization of the wafer is realized.

It should be understood that the cmp apparatus 100 of the present invention is not limited to the adjustment of the material removal rate at the edge portion of the wafer, but may be applicable to the control of the material removal rate at other portions of the wafer, such as the center portion of the wafer, the middle portion of the wafer, etc. The cmp apparatus 100 is not limited to reducing the removal rate of material, but may also increase the removal rate of material to achieve global planarization of the wafer.

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 apparatus, comprising:

polishing disk;

2. The chemical mechanical polishing apparatus according to claim 1, wherein the pressure adjusting portion is in communication with the seal chamber through a pipe, and the pressure adjusting portion includes a gas source and an adjusting valve that evacuates or vents the seal chamber to adjust the pressure of the seal chamber.

3. The chemical mechanical polishing apparatus according to claim 2, wherein the polishing pad on the upper side of the groove is deformed toward the lower side when the seal chamber is under negative pressure, so that the rebound height of the polishing pad on the upper side of the groove is reduced in a pressed state.

4. The chemical mechanical polishing apparatus according to claim 1, wherein the bottom of the groove is provided with a plurality of connection holes uniformly distributed along the circumference; the pressure regulating part is communicated with the connecting hole through the main pipeline and the branch pipeline so as to evacuate or ventilate the sealing cavity.

5. The chemical mechanical polishing apparatus according to claim 4, wherein the main pipe is concentrically disposed at a lower portion of the polishing platen, and the branch pipe is disposed between the main pipe and the connection hole and is radially distributed centering around the main pipe.

6. The chemical mechanical polishing apparatus according to claim 1, wherein the grooves are ring-shaped structures concentrically disposed on the top surface of the polishing platen.

7. The chemical mechanical polishing apparatus according to claim 1, further comprising an adjustment member disposed in a groove of the polishing platen; the regulating member extends to the top surface of the polishing disk toward the upper side.

8. A chemical mechanical polishing method using the chemical mechanical polishing apparatus according to any one of claims 1 to 7, comprising the steps of:

9. The chemical mechanical polishing method of claim 8, wherein the wafer is controlled to move toward the recess when the removal rate of the edge of the wafer is higher than the set removal rate.

10. The chemical mechanical polishing method of claim 9, wherein the wafer moves across the surface of the polishing pad and the outer edge of the wafer moves within 1/2 of the width of the recess.