CN113118969A

CN113118969A - Bearing head for chemical mechanical polishing

Info

Publication number: CN113118969A
Application number: CN201911411261.1A
Authority: CN
Inventors: 赵德文; 刘远航; 王宇; 孟松林
Original assignee: Tsinghua University; Huahaiqingke Co Ltd
Current assignee: Tsinghua University; Huahaiqingke Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-07-16

Abstract

A carrier head for chemical mechanical polishing comprises a coupling disc, a balance frame, a carrier disc, a flexible membrane and an annular pressure disc, wherein a middle shaft part of the balance frame is arranged in a central through hole of the coupling disc in a sliding and sealing mode and can drive the carrier disc to move up and down relative to the coupling disc through a bottom disc part and a flange part of the balance frame, the flexible membrane is provided with an edge corrugated wall and at least one inner corrugated wall used for dividing a pressure chamber, at least one of the edge corrugated wall and the innermost inner corrugated wall is tightly and directly clamped to the carrier disc through the annular pressure disc in an airtight mode to form a pressure-adjustable chamber, and therefore pressure applied to a substrate can be adjusted through controlling the horizontal position of the balance frame and the pressure of the pressure chamber.

Description

Bearing head for chemical mechanical polishing

Technical Field

The invention belongs to the technical field of chemical mechanical polishing, and particularly relates to a bearing head for chemical mechanical polishing.

Background

Chemical mechanical polishing is a mainstream method for polishing substrates in the field of chip manufacturing. The polishing method generally attracts and holds the substrate at the lower part of the carrier head, one surface of the substrate with a deposition layer abuts against the rotating polishing pad, and the carrier head rotates in the same direction with the polishing pad under the driving of the driving part and gives a downward load to the substrate; meanwhile, the polishing solution is supplied to the upper surface of the polishing pad and distributed between the substrate and the polishing pad, so that the substrate is subjected to global polishing under the combined action of chemistry and machinery.

On the one hand, as the feature size of electronic devices is continuously reduced, the process requirements of the manufacturing process for chemical mechanical polishing are higher and higher, thereby leading to more and more gas chamber partitions in the carrier head. The structure of the bearing head is gradually complicated, the number and the combination relation of parts reach the unprecedented complexity, the challenges are brought to the assembly operation and the maintenance operation, and the high precision requirement and the cost requirement are provided for the part processing; in addition, the detection accuracy requirement of the chemical mechanical polishing end point detection is also improved along with the continuous reduction of the size of the characteristic structure, so a certain requirement is also put forward on the whole electromagnetic signal reflection performance of the bearing head, and the electromagnetic measurement signals are hopefully reflected by other metal parts on the bearing head as few as possible when the characteristic thickness of the metal structure on the substrate is measured; moreover, the carrier head is required to rapidly pick and place the substrate and reduce the possible influence on the substrate in the process of pressurizing the substrate, so as to prevent the substrate from being damaged.

On the other hand, the bearing head is an important component of the chemical mechanical polishing unit, the bearing head in the related art is equivalent to a universal joint, the balance frame assembly can only absorb the vertical vibration between the clamping piece assembly and the base, and the balance frame assembly does high-speed rotary motion relative to the base under the drive of the rotary driving mechanism, so that the balance frame assembly can deflect to a certain extent, can generate circumferential swing, and has the problems of insufficient centering function and poor adaptability.

Further, it is desirable that the carrier head reduce vibration and oscillation and enhance balance and compliance during operation, and thus a carrier head that improves polishing uniformity and consistency is desired.

Disclosure of Invention

The present invention is directed to solving some of the above problems, and in view of the above, the present invention provides a carrier head for chemical mechanical polishing, comprising a coupling plate, a balance frame, a carrier plate, a flexible membrane, and an annular pressure plate, wherein a middle shaft portion of the balance frame is slidably and sealingly disposed in a central through hole of the coupling plate and can drive the carrier plate to move up and down relative to the coupling plate via a bottom plate portion and a flange portion thereof, the flexible membrane has an edge bellows for partitioning a pressure chamber and at least one inner bellows, and at least one of the edge bellows and the innermost inner bellows is hermetically and directly clamped to the carrier plate by the annular pressure plate to form a pressure-adjustable chamber, so that a pressure applied to a substrate can be adjusted by controlling a horizontal position of the balance frame and a pressure of the pressure chamber.

Preferably, the edge corrugation extends vertically upward along the upper surface of the flexible membrane, the inner corrugation extends upward along the upper surface of the flexible membrane, and the edge sidewall is concentrically disposed with the inner corrugation.

Preferably, the edge corrugation has an annular first horizontal extension extending horizontally radially inwardly from a top end thereof and the first horizontal extension has an annular first sealing projection at a free end thereof, and the inner corrugation has an annular second horizontal extension extending horizontally radially from a top end thereof and the second horizontal extension has an annular second sealing projection at a free end thereof.

Preferably, a portion of the first horizontally extending portion adjacent to the first sealing projection is air-tightly clamped and fixed to the lower surface of the carrier plate together with the first sealing projection by an upper outer edge portion of the annular pressure plate.

Preferably, a portion of the second horizontally extending portion adjacent to the second sealing projection is air-tightly clamped and fixed to the lower surface of the carrier plate together with the second sealing projection by an upper inner edge portion of the annular pressure plate.

Preferably, the upper surface and/or the edge of the annular pressure plate has a second positioning and clamping structure for receiving the second sealing protrusion.

Preferably, the upper surface and/or the edge of the annular pressure plate has a first positioning and clamping structure for receiving the first sealing protrusion.

Preferably, the inner gusset extends upwardly to a vertical height less than the vertical height of the edge gusset.

Preferably, the first and second horizontally extending portions have different lengths.

Preferably, the first sealing protrusion and the second sealing protrusion surface have a roughness structure for enhancing a clamping effect and preventing sticking.

Preferably, the other portions of the flexible membrane except for the first sealing protrusion and the second sealing protrusion are coated with a hydrophobic material.

Preferably, the hydrophobic material is parylene C powder.

According to another aspect of the invention, there is also provided a chemical mechanical polishing apparatus comprising a carrier head as described above.

Benefits of embodiments according to the present invention include, but are not limited to, increased operational consistency and uniformity of the carrier head, improved polishing, more uniform pressurization, and more particularly, to the extent that the gimbal is prevented from transferring lateral forces experienced by the carrier head to the retaining ring of the carrier head when the carrier head is subjected to lateral friction forces.

Drawings

In order to further clearly illustrate the embodiments of the present invention and/or the related technical solutions in the prior art, the drawings and the main contents thereof which are needed to be used in the description of the embodiments and the prior art according to the present invention will be briefly described below, it is obvious that the drawings in the following description are only a part of the embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts according to the provided drawings.

FIG. 1 is a schematic diagram of a chemical mechanical polishing carrier head according to one embodiment of the present invention;

FIG. 2A is a schematic view of a gimbal of a carrier head provided in accordance with one embodiment of the present invention;

FIGS. 2B and 2C respectively illustrate variations of a gimbal of a chemical mechanical polishing carrier head in accordance with the present invention;

FIG. 3 is a schematic view of an adapter plate of a carrier head provided by one embodiment of the invention;

FIG. 4 is a schematic view of a carrier platter of a carrier head provided in accordance with one embodiment of the present invention;

FIG. 5 is a schematic view of a flexible membrane of a carrier head provided by one embodiment of the invention;

FIG. 6 is a schematic diagram illustrating the operation of the eddy current testing apparatus;

FIG. 7 illustrates a variation of a chemical mechanical polishing carrier head in accordance with the present invention;

figure 8 illustrates a variation of a gimbal for a chemical mechanical polishing carrier head in accordance with the present invention.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the following embodiments and accompanying drawings. The embodiments described herein are specific embodiments of the present invention for the purpose of illustrating the concepts of the invention; the description is intended to be illustrative and exemplary and should not be taken to limit the scope of the invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification thereof, and these technical solutions include technical solutions which make any obvious replacement or modification of the embodiments described herein. It should be understood that, unless otherwise specified, the following description of the embodiments of the present invention is made for the convenience of understanding, and the description is made in a natural state where relevant devices, apparatuses, components, etc. are originally at rest and no external control signals and driving forces are given.

One embodiment of a carrier head 1 for chemical mechanical polishing according to the present invention is shown in fig. 1, and includes a balance 11, a coupling disk 12, a carrier disk 13, a flexible membrane 14, and an annular platen 15; the first clamp ring 20 clamp-couples the outer edge of the annular elastic membrane 21 to the carrier disc 13 and the second clamp ring 23 clamp-couples the inner edge of the annular elastic membrane 21 to the coupling disc 12, so that the coupling disc 12 can bring the carrier disc 13 to synchronously and coaxially rotate via the annular elastic membrane 21 when the coupling disc 12 rotates together with the external drive shaft; the third clamping ring 18 and the

annular gaskets

17A, 17B clamp the balance 11 to the carrier plate 13, and the annular pressure plate 15 hermetically clamps the flexible membrane 14 to the lower part of the carrier plate 13 so that the flexible membrane 14 can rotate with the carrier plate 13 and the balance 11 and move up and down relative to the coupling plate 12; the retaining ring 16 is fixedly coupled to the lower surface of the carrier disk 13, and the coupling disk 12 is coupled to the external drive shaft when the carrier head 1 is operated, and the substrate to be processed is received and retained on the lower surface of the flexible film 14 inside the retaining ring 16.

As shown in fig. 2A, the gimbal 11 is composed of a middle shaft portion 111, a bottom plate portion 112, a peripheral wall portion 113 and a flange portion 114, the middle shaft portion 111, the bottom plate portion 112, which is a disk shape, is coaxially formed at the bottom of the middle shaft portion 111 and has a radius at least 3 times of the radius of the middle shaft portion 111, the peripheral wall portion 113 extends vertically upward along the circumferential edge of the bottom plate portion 112 to a height not more than half of the height of the middle shaft portion 111 to form a semi-closed annular cylindrical stroke chamber 116 having a certain height, and the annular flat flange portion 114 is formed by extending horizontally outward from the upper outer surface of the peripheral wall portion 113 and has a thickness equal to or more than the thickness of the bottom plate portion 112 and/. In addition, the middle shaft portion 111 has a first through hole 115 disposed along its axis and penetrating to the lower surface of the bottom plate portion 112, and an external gas source, not shown, may supply gas into the carrier head 1 or extract gas from the carrier head 1 through the first through hole 115 to adjust the pressure of the chamber in the carrier head 1.

Fig. 2B and 2C show an alternative modified gimbal 41 of the gimbal, in which the gimbal 41 is composed of a central shaft 411 extending vertically, a disk-shaped base 412 disposed at a bottom end of the central shaft 411, a ring-shaped peripheral wall 413 extending vertically and upwardly from a circumferential edge of the base 412, and a ring-shaped flange 414 extending horizontally outwardly from an outer surface of the peripheral wall 413 near a top end; wherein a horizontally outwardly extending annular connecting flange 4111 is formed below the center shaft 411 near the bottom end, the connecting flange 4111 divides the main shaft into an upper shaft portion 411A formed at the upper portion of the connecting flange 4111 and a lower shaft portion 411B formed at the lower portion of the connecting flange 4111, and a cylindrical groove 4121 for receiving the lower shaft portion 411B is formed at the center of the upper surface of the base plate 412, the lower shaft portion 411B is inserted into the cylindrical groove 4121 and the connecting flange 4111 is coaxially connected to the upper surface of the base plate 412 via an annular cushion ring 415.

In order to supply gas from the outside of the carrier head 1 to the inside thereof to act on the elastic mold 21, the center shaft 411 and the bottom of the cylindrical groove 4121 are formed with a through-hole 416 composed of a center shaft through-hole 416A formed along the center axis of the center shaft 411 and a bottom plate through-hole 416B formed in the center of the bottom surface of the groove 4121 of the bottom plate 412. It will be readily appreciated that the flexible attachment of the bottom bracket 412 to the bottom bracket 411 is achieved by clamping the connecting flange 4111, the cushion 415 and the bottom bracket 412 together by fasteners such as bolts 417, which have some flexibility and flexibility to maintain balance and reduce vibration when the circumference of the gimbal 41 is loaded. Alternatively, pressure sensitive adhesive may be used to secure the flange 4111, the cushion 415, and the bottom plate 412 together to achieve a flexible attachment of the central shaft 411 to the bottom plate 412. Preferably, the cushion 415 may be made of one, two or more of thermoplastic polyvinyl chloride material, hard or soft plastic, polymer material, PTFE plastic, PPS plastic, PEEK plastic, PET plastic, etc., and carbon fiber, glass fiber, graphene material, etc., may be mixed therein to improve its performance.

Preferably, the upper surface and/or the lower surface of the cushion 415 is provided with a texture and/or a concave-convex structure to improve the contact flexibility thereof, and similarly, the lower surface of the connecting flange 4111 of the central shaft 411 is formed with a texture or a rough structure to further increase the contact flexibility thereof with the cushion 415, and the upper surface of the central annular region of the bottom chassis 412 contacting the cushion 415 is also formed with a texture or a rough structure to increase the contact flexibility thereof with the cushion 415; thereby increasing the stability of the balance frame 41. Further, the outer circumference of the cushion 415 extends in its radial direction to be aligned with the circumferential outer edge of the flange 4111, and the inner circumference of the cushion 415 extends in its radial direction to be aligned with the circumferential wall of the groove 4121. Preferably, the bottom chassis 412 may be formed in a concave structure having a high outer side and a low inner side as shown in fig. 2B, and a downward projection 4122 is formed at the center thereof to prevent the substrate from being locally collided or damaged by concentrated force when the central portion of the elastic mold 21 excessively lifts the substrate.

Further, lower spindle portion 411B is formed to have a radius smaller than that of groove 4121 so that a gap of 1mm to 6mm is formed between the circumferential outer wall of lower spindle portion 411B and the circumferential inner wall of cylindrical groove 4121, and a circumferential edge of the bottom of lower spindle portion 411B is extended outward to form a ring-shaped retaining rim 4114, and a vertical section of retaining rim 4114 is approximately semicircular in shape so that a line contact is formed between the outer edge thereof and the inner wall of cylindrical groove 4121, thereby increasing the flexibility of balance frame 41 in cooperation with cushion ring 415. It should be understood that a plurality of bolt holes 4115 may be uniformly arranged on the connecting flange 4111 along the circumferential direction to fix the connecting flange 4111, the cushion washer 415 and the chassis 412 together by metal bolts or non-metal bolts made of non-metal materials such as plastics, preferably bolts made of aluminum or metal materials with low relative magnetic permeability and/or bolts made of plastics. Further, the main shaft 411 of the balance frame 41 may be made of a metal material with low magnetic permeability such as aluminum, and the chassis 412 is preferably made of a metal material with low magnetic permeability or a non-metal material such as plastic; as a modification, the center shaft 411 may also be formed as in the embodiment described in fig. 8, the details of which will be described later.

As shown in fig. 3, the coupling disc 12 is composed of a cylindrical main body portion 121 and a peripheral edge portion 122, and the main body portion 121 has a second through hole 123 extending therethrough along the central rotational axis thereof and at least one third through hole 124 parallel to the second through hole 123. The outer diameter of the body portion 121 is slightly smaller than the inner diameter of the cylindrical stroke chamber 116 so as to be insertable downward into the cylindrical stroke chamber 116 when the body portion 121 moves downward relative to the balance frame 11, and the inner diameter of the second through-hole 123 matches the outer diameter of the middle shaft portion 111 of the balance frame 11 so that the middle shaft portion 111 can be slidably inserted into the second through-hole 123 and airtightly slide therein in the vertical direction; in other words, the balance frame 11 is vertically movable up and down along the common central rotational axis thereof by being fitted to the second through hole 123 of the coupling disc 12 via the middle shaft portion 111.

As shown in fig. 4, the carrier plate 13 is a circular plate with a certain thickness, and has a step hole 131 extending through along the central rotation axis, and the step hole 131 is composed of a first step hole 131A, a second step hole 131B, a third step hole 131C, and a fourth step hole 131D, wherein the 4 step holes have different radii and increase from bottom to top. The inner diameter of the first step hole 131A is slightly larger than the outer diameter of the bottom plate portion 112 of the balance frame 11, the inner diameter of the second step hole 131B is slightly larger than the distance from the outer end of the flange portion 114 to the central rotation axis, and the inner diameter of the fourth step hole 131D is slightly larger than the outer diameter of the peripheral portion 122 of the coupling disc 12, so that the balance frame 11 is clamped and fixed into the step hole 131 by the

annular washers

17A, 17B and the third clamp ring 18 to form a relatively closed variable-volume first pressure chamber 25 composed of the inner surface of the cylindrical stroke chamber 116, the inner surface and the upper surface of the third clamp ring 18, the bottom surface and the side surface of the fourth step hole 131D, the lower surface of the annular elastic membrane 21, the lower surface and the outer surface of the second clamp ring 23, and the lower surface of the coupling disc 12 not covered by the second clamp ring 23, as shown in fig.

When gas is introduced into the first pressure chamber 25 through the third through-opening 124, the gas pressure in the first pressure chamber 25 increases such that the combined balancing stand 11 and carrier plate 13 moves downwards relative to the coupling plate 12, and the volume of the first pressure chamber 25 increases accordingly; similarly, when gas is drawn out of the first pressure chamber 25 through the third through hole 124, the gas pressure in the first pressure chamber 25 decreases so that the combined balance 11 and carrier plate 13 moves upward relative to the coupling plate 12, and the volume of the first pressure chamber 25 decreases accordingly. Vertical movement of the gimbal 11 and carrier plate 13 translates the flexible membrane 14 and annular platen 15 to actuate and/or hold the substrate.

Further, the lower edge of the peripheral portion 122 of the coupling disc 12 has a recess for receiving the second clamp ring 23, the depth of the recess being configured such that when the second clamp ring 23 and the third clamp ring 18 are fixed to the coupling disc 12 and the carrier disc 13 via fixing members such as bolts (not shown), respectively, the lower surface of the second clamp ring 23 is flush with the lower surface of the peripheral portion 122 of the coupling disc 12 and the upper surface of the third clamp ring 18 is flush with the bottom surface of the fourth step hole 131D of the stepped hole 131.

The flexible membrane 14 functions to cooperate with other portions of the carrier head 1 to form at least one pressure-regulated gas chamber to further fine tune the pressure profile applied to the substrate to improve the uniformity and consistency of the chemical mechanical polishing. To this end, as shown in fig. 5, the flexible film 14 is formed of a circular bottom plate portion 141, an annular edge bellows 142, and at least one annular inner bellows 143, the edge bellows 142 vertically extending upward along the circumferential edge of the circular bottom plate portion 141 and horizontally extending toward the radially inner side at the tip end thereof for a distance to form an annular first horizontal extending portion 144, and the first horizontal extending portion 144 having an annular first sealing projection 145 at the inner edge thereof; similarly, an annular inner corrugated wall 143 is provided concentrically and in parallel with the edge corrugated wall 142 and radially inside thereof, the inner corrugated wall 143 extends vertically upward from the upper surface of the circular bottom plate portion 141 and horizontally extends at a tip end thereof toward the radially outer side by a distance to form an annular second horizontal extending portion 146, and the second horizontal extending portion 146 has an annular second sealing projection 147 at an outer edge thereof. As shown in fig. 1, the first sealing protrusion 145 and its adjacent portion are clamped and fixed by the upper portion of the outer edge of the annular pressure plate 15 into the annular groove of the lower surface of the carrier plate 13 via bolts (not shown), and the second sealing protrusion 147 and its adjacent portion are clamped and fixed by the upper portion of the inner edge of the annular pressure plate 15 into the lower portion of the inner edge near the first step hole 131A, thereby forming a relatively sealed pressure-adjustable second pressure chamber 24A and a third pressure chamber 24B, respectively, whose pressure can be adjusted by introducing or withdrawing gas into or from the second pressure chamber 24A through the first through hole 115, and similarly, gas can be introduced into or withdrawn from the third pressure chamber 24B through other through holes or fluid passages, not shown, to adjust the pressure of the chambers.

As can be seen from the above description, the relative position between the carrier head 1 and the substrate in the vertical direction can be controlled by adjusting the pressure of the first pressure chamber 25, and the pressure profile applied to the substrate can be further adjusted by adjusting the pressures of the second pressure chamber 24A and the third pressure chamber 24B, and in order to monitor the polishing process in real time, the thickness of the polished substrate, i.e., the real-time thickness of the functional film layer on the substrate, needs to be measured by the eddy current sensor and/or the optical sensor.

As shown in fig. 6, when the carrier head 1 presses the substrate 201 against the polishing pad on the polishing pad to perform the polishing operation, the eddy current film thickness measuring device 203 mounted on the polishing pad is required to measure the thickness of the metal film 202 on the surface of the substrate 201 to determine the polishing endpoint, since the metal material has a reflection effect on the electromagnetic wave emitted by the eddy current film thickness measuring device 203 and the non-metal material generally transmits the electromagnetic wave, and the reflection intensity of the electromagnetic wave is substantially positively correlated with the thickness of the metal film within a certain range, the film thickness can be measured by the eddy current film thickness measuring device 203 emitting the electromagnetic wave toward the metal film 202 on the substrate 201 and measuring the intensity of the electromagnetic wave reflected by the metal film 202. The gimbal 11 is usually made of a metal material having a high strength such as stainless steel so as to satisfy the strength requirement, however, when the bottom plate portion 112 of the gimbal 11 is made of a metal material, since it is closer to the eddy current film thickness measuring device 203 than the flange portion 114 so that it reflects the electromagnetic wave emitted from the eddy current film thickness measuring device 203 to a large extent, it has a hardly negligible influence on the thickness measurement accuracy of the metal film layer 202, thereby affecting the detection of the polishing end point.

For this reason, it is preferable to manufacture the gimbal 11 from a material having a low relative permeability and/or electric conductivity (closer to 1), such as austenitic stainless steel of 304, aluminum-magnesium alloy, and/or titanium alloy, and since the relative permeability of such a material is less than 1.01, the reflection of electromagnetic waves is very weak, and the influence on the measurement accuracy of the film thickness is acceptable. It should be understood that the dimensions of the substrate 201, the metal film layer 202, and the eddy current film thickness measuring device 203 in fig. 6 do not represent actual dimensions thereof, nor do they represent a proportional relationship between the dimensions thereof, and are shown only for the purpose of embodying their functions.

Although the metal material having a low relative magnetic permeability can reduce the influence of the bottom plate portion 112 of the balance frame 11 on the measurement signal of the eddy current sensor, since the thickness of the metal film layer is as thin as up to 1000nm and the error requirement on the measurement accuracy is generally less than 10nm, it is necessary in some cases to further reduce the influence of the material of the balance frame 11 on the film thickness measurement result, that is, to further reduce the reflection of the electromagnetic wave by the bottom plate portion 112 of the balance frame 11. Preferably, as shown in fig. 7, a wave-absorbing layer 204 may be disposed on the lower surface of the chassis part 112 of the balance frame 11, the wave-absorbing layer 204 has a thickness of generally 0.05mm to 1mm, and the wave-absorbing layer 204 is generally made of a material such as ferrite, barium titanate, silicon carbide, graphite, metal powder, conductive fiber, chiral material, or the like. As will be readily appreciated, the wave-absorbing layer 204 can be bonded to the entire lower surface of the chassis portion 112 by various coating methods such as adhering wave-absorbing patches, painting an adhesive containing wave-absorbing powder material, vapor depositing wave-absorbing material, electroplating wave-absorbing material, etc., and preferably, the radius of the wave-absorbing layer 204 is larger than the radius of the chassis portion 112 to cover adjacent areas at the edge of the chassis portion, thereby further reducing the potential impact of the gimbal 11 on film thickness measurement; it is easily understood that the wave-damping layer 204 does not cover the first through-hole 115.

In the foregoing embodiment, the balance frame 11 is generally integrally machined from a metal material to meet the requirements of strength and machining precision, but in order to further reduce the influence of the chassis portion of the balance frame on the film thickness measurement, it may alternatively be formed as the scheme shown in fig. 8, wherein the middle shaft portion 311 of the balance frame 31 is composed of a middle shaft core 311A and a middle shaft sleeve 311B, the middle shaft core 311A is integrally formed with the chassis portion 312, the peripheral wall portion 313, and the flange portion 314 by the same non-metal material, the middle shaft sleeve 311B is made of a metal material and has, thereunder, a connecting hole for combining the middle shaft core 311A, the size of the connecting hole is matched with that of the middle shaft core 311A so that the middle shaft core 311A can be completely coaxially inserted and adhesively fixed in the connecting hole and an airtight combination between the inner surface of the connecting hole and the outer surface of the middle shaft core 311A is ensured; the center shaft core 311A has a center shaft core through hole 315A extending therethrough along an axis thereof, the center shaft sleeve 311B has a center shaft sleeve through hole 315B extending therethrough along an axis thereof, and when the center shaft sleeve 311B is coupled to the center shaft core 311A, the center shaft core through hole 315A and the center shaft sleeve through hole 315B having the same radius are aligned with each other to form a gimbal through hole 315 extending therethrough along a rotation axis of the gimbal 31.

As shown in fig. 8, in consideration of the processing technology and strength requirements, the height of the middle shaft core 311A may be 30% to 60% of the total height of the middle shaft sleeve 311B, but in some application scenarios, the middle shaft core 311A may also extend vertically upward to the upper surface of the middle shaft sleeve 311B, that is, the height of the middle shaft core 311A is equivalent to the height of the middle shaft sleeve 311B; in consideration of the requirements for reflection and intensity of electromagnetic waves, the radius of the central shaft core 311A should be at least not less than 50% of the radius of the central shaft sleeve 311B, in other words, the thickness of the hole wall of the connection hole at the lower portion of the central shaft sleeve 311B should not exceed 50% of the entire radius of the central shaft sleeve 311B. Preferably, in order to ensure the action tolerance between different parts of the gimbal 31, the gimbal through hole 315 formed by the central axis through hole 315A and the central bushing through hole 315B is formed by machining after fixedly bonding the central axis core 311A and the central bushing 311B together, and at least one of the bottom plate part 312, the peripheral wall part 313 and the flange part 314 is also formed by machining after fixedly bonding the central axis core 311A and the central bushing 311B together.

The material forming the part of the central shaft core 311A is plastic material such as PPS plastic, PEEK plastic, PET plastic, or other non-metal materials such as ceramic, semiconductor, etc., and it is preferable to add reinforcing material such as glass fiber, carbon fiber, or ceramic thereto or directly use composite plastic with better strength to manufacture these parts, or it is also possible to manufacture the central shaft core 311A using material such as titanium or titanium alloy; the middle sleeve 311B is preferably made of a metallic material having a relatively low magnetic permeability, such as austenitic stainless steel having a grade of 304, aluminum-magnesium alloy, titanium alloy, or the like. It should be understood that the diameter of the central axis 311A near the bottom plate 312 may be larger than the diameter of other parts to enhance the strength of the joint of the central axis 311A and the bottom plate 312, and the joint of the central axis 311A and the bottom plate 312 is preferably rounded to optimize the strength of the joint; further, in order to further reduce the influence that the middle shaft sleeve 311B made of metal may have on the measurement accuracy of the eddy current film thickness measuring apparatus 203, a layer of wave-absorbing material may be coated on the surface thereof, or a layer of wave-absorbing material may be coated on a root region of the middle shaft core 311A of the middle shaft sleeve 311B that is in contact with the bottom portion thereof.

Further, as shown in fig. 2 and 8, the balancing stand 31 is also different from the balancing stand 11 in that the whole or a part of the bottom of the balancing stand 21 is formed to be downwardly convex, and the height of the downwardly convex does not exceed the height of the inner corrugated wall 143; such downward protrusions serve to prevent the central portion of the substrate from being excessively pulled due to excessive deformation of the second pressure chamber 24A during loading of the substrate, i.e., being blocked by the downward protrusions when the central region of the substrate is excessively pulled, thereby preventing local excessive deformation of the substrate and/or damage to the features of the substrate that may result from excessive pulling.

The drawings in the present specification are schematic views to assist in explaining the concept of the present invention, and schematically show the shapes of respective portions and their mutual relationships. It should be understood that the drawings are not necessarily to scale, the same reference numerals being used to identify the same elements in the drawings in order to clearly show the structure of the elements of the embodiments of the invention. In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean 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, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. 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 invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A carrier head for chemical mechanical polishing comprises a coupling disc, a balance frame, a carrier disc, a flexible membrane and an annular pressure disc, wherein a middle shaft part of the balance frame is arranged in a central through hole of the coupling disc in a sliding and sealing mode and can drive the carrier disc to move up and down relative to the coupling disc through a bottom disc part and a flange part of the balance frame, the flexible membrane is provided with an edge corrugated wall and at least one inner corrugated wall used for dividing a pressure chamber, at least one of the edge corrugated wall and the innermost inner corrugated wall is tightly and directly clamped to the carrier disc through the annular pressure disc in an airtight mode to form a pressure-adjustable chamber, and therefore pressure applied to a substrate can be adjusted through controlling the horizontal position of the balance frame and the pressure of the pressure chamber.

2. The carrier head of claim 1, wherein the edge corrugation extends vertically upward along the flexible membrane upper surface, the inner corrugation extends upward along the flexible membrane upper surface, and the edge sidewall is concentrically disposed with the inner corrugation.

3. The carrier head of claim 1 wherein the edge corrugation has an annular first horizontal extension extending horizontally radially inwardly from a top end thereof and the first horizontal extension has an annular first sealing projection at a free end thereof, and the inner corrugation has an annular second horizontal extension extending horizontally radially from a top end thereof and the second horizontal extension has an annular second sealing projection at a free end thereof.

4. The carrier head of claim 3, wherein a portion of the first horizontal extension adjacent the first sealing protrusion is hermetically clamped to the lower surface of the carrier platter by an upper outer edge portion of the annular platen together with the first sealing protrusion.

5. The carrier head of claim 3, wherein a portion of the second horizontal extension adjacent the second sealing protrusion is hermetically clamped to the lower surface of the carrier platter by an upper inner edge portion of the annular platen together with the second sealing protrusion.

6. The carrier head of claim 1, wherein the upper surface and/or edge of the annular platen has a second locating and clamping feature for receiving the second sealing protrusion.

7. The carrier head of claim 1, wherein an upper surface and/or edge of the annular platen has a first locating gripping structure for receiving the first sealing protrusion.

8. The carrier head of claim 1, wherein the inner corrugation extends upwardly to a vertical height less than a vertical height of the edge corrugation.

9. The carrier head of claim 3, wherein the first horizontally extending portion and the second horizontally extending portion are different lengths.

10. The carrier head of claim 3, wherein the first sealing protrusion and the second sealing protrusion surface have a roughness to enhance clamping and prevent stiction.

11. The carrier head of claim 3, wherein portions of the flexible membrane other than the first sealing protrusion and the second sealing protrusion are coated with a hydrophobic material.

12. The carrier head of claim 11, wherein the hydrophobic material is parylene C powder.

13. A chemical mechanical polishing apparatus, characterized in that the chemical mechanical polishing apparatus comprises a carrier head according to any one of claims 1 to 12.