CN116512114A - Carrier head for chemical mechanical polishing and application method thereof - Google Patents

Carrier head for chemical mechanical polishing and application method thereof Download PDF

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Publication number
CN116512114A
CN116512114A CN202310739537.9A CN202310739537A CN116512114A CN 116512114 A CN116512114 A CN 116512114A CN 202310739537 A CN202310739537 A CN 202310739537A CN 116512114 A CN116512114 A CN 116512114A
Authority
CN
China
Prior art keywords
chamber
wafer
elastic
carrier head
shaft
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310739537.9A
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Chinese (zh)
Inventor
孟松林
温世乾
马逸麟
孙张璞
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Huahaiqingke Co Ltd
Original Assignee
Huahaiqingke Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huahaiqingke Co Ltd filed Critical Huahaiqingke Co Ltd
Priority to CN202310739537.9A priority Critical patent/CN116512114A/en
Publication of CN116512114A publication Critical patent/CN116512114A/en
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/27—Work carriers
    • B24B37/30—Work carriers for single side lapping of plane surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/005—Control means for lapping machines or devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
    • B24B49/16—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the load
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

The invention discloses a bearing head for chemical mechanical polishing and a use method thereof, wherein the bearing head comprises: a main matrix; an elastic membrane connected to the lower side of the main base body through a carrying disc; the detection assembly is arranged in the mounting hole of the bearing disc and corresponds to one cavity of the elastic membrane, and the corresponding cavity of the detection assembly is a detection cavity; the detection assembly comprises a pin shaft, a sealing element, an elastic element and a fixing element, wherein the pin shaft is arranged in a vent hole of the bearing disc in a clearance mode, the sealing element and the elastic element are sleeved on the periphery side of the pin shaft, the sealing element is arranged at the bottom of the mounting hole, the elastic element is arranged at the upper part of the pin shaft, and the fixing element is connected above the mounting hole in a sealing mode and is abutted to the upper end of the elastic element; the compressed elastic piece can push the pin shaft to press the sealing piece, so that the fixing piece and the mounting hole form a sealed auxiliary chamber; at least part of the pin shaft is positioned in the detection chamber and can move vertically so as to change the on-off of the auxiliary chamber and the detection chamber.

Description

Carrier head for chemical mechanical polishing and application method thereof
Technical Field
The invention belongs to the technical field of chemical mechanical polishing, and particularly relates to a bearing head for chemical mechanical polishing and a using method thereof.
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 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 having a deposited layer abutting against the upper surface of a polishing pad, the carrier head rotating in the same direction as the polishing pad under actuation of a drive assembly and imparting a downward load to the wafer; the polishing liquid 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.
Before polishing a wafer, the carrier head needs to load the wafer from a load cup (load cup) and then polish the wafer on a polishing pad. In the wafer loading process, whether the carrier head successfully attracts the wafer or not needs to be judged; if the carrier head does not successfully absorb the wafer in the loading process, loading alarm can occur to influence that the chemical mechanical polishing cannot be normally carried out.
In the prior art, after a carrier head loads a wafer, whether the carrier head attracts the wafer is generally determined indirectly by the state of the wafer in a loading device. Specifically, after the loading operation is completed by the carrier head, if the carrier head successfully attracts the wafer, the wafer leaves the loading device; if the carrier head fails to pick up the wafer, the wafer is still on the loading device. That is, whether the carrier head successfully suctions the wafer is judged by detecting whether the wafer is in the loading device. But this increases the complexity of the loading device and affects the stability of the operation of the loading device.
In addition, a pressure sensor is configured for the carrier head, for example, a pressure sensor is arranged in the elastic membrane, and whether the carrier head attracts the wafer is detected by the pressure sensor. Since the operation of the pressure sensor requires electrical power, the existing carrier head requires external configuration of the power supply components, which increases the complexity of the carrier head.
Disclosure of Invention
The embodiment of the invention provides a bearing head for chemical mechanical polishing and a using method thereof, which aim to at least solve one of the technical problems in the prior art.
A first aspect of an embodiment of the present invention provides a carrier head for chemical mechanical polishing, comprising:
a main matrix;
an elastic membrane connected to the lower side of the main base body through a carrying disc;
the detection assembly is arranged in the mounting hole of the bearing disc and corresponds to one cavity of the elastic membrane, and the corresponding cavity of the detection assembly is a detection cavity;
the detection assembly comprises a pin shaft, a sealing element, an elastic element and a fixing element, wherein the pin shaft is arranged in a vent hole of the bearing disc in a clearance mode, the sealing element and the elastic element are sleeved on the periphery side of the pin shaft, the sealing element is arranged at the bottom of the mounting hole, the elastic element is arranged at the upper part of the pin shaft, and the fixing element is connected above the mounting hole in a sealing mode and is abutted to the upper end of the elastic element; the compressed elastic piece can push the pin shaft to press the sealing piece, so that the fixing piece and the mounting hole form a sealed auxiliary chamber; at least part of the pin shaft is positioned in the detection chamber and can move vertically so as to change the on-off state of the auxiliary chamber and the detection chamber.
In some embodiments, the wafer sucked by the elastic film can push the pin shaft to move upwards, so that the auxiliary chamber is communicated with the detection chamber; the auxiliary chamber is communicated with the judging chamber of the elastic membrane, so that the pressure of the detecting chamber is equal to the pressure of the judging chamber.
In some embodiments, the pin shaft comprises an upper shaft section, a lower shaft section and a shaft shoulder arranged between the upper shaft section and the lower shaft section, an elastic piece is arranged on the outer periphery side of the upper shaft section, a sealing piece is arranged between the shaft shoulder and the bottom surface of the mounting hole, and the lower shaft section is coaxially arranged in the vent hole.
In some embodiments, the outer peripheral side of the lower shaft section is provided with a recess, which is disposed along the length direction of the pin shaft; the inner side wall of the vent hole is provided with a convex part which is penetrated along the thickness direction of the bearing plate; the recess matches the shape and size of the protrusion.
In some embodiments, the number of recesses is a plurality, which are evenly distributed along the lower shaft section.
In some embodiments, the recess has a cross-sectional shape that is semi-circular, rectangular, triangular, and/or dove-tail.
In some embodiments, the clearance between the pin and the vent is no greater than 0.2mm.
In some embodiments, a blind hole for placing the elastic element is configured below the fixing element, a limiting hole is configured on the top surface of the blind hole, and the upper end of the elastic element is clamped in the limiting hole.
In some embodiments, the pin is made of a metallic material or a non-metallic material.
In some embodiments, the pin includes a shaft body and a shaft cap, the shaft body being removably connected to the shaft cap; the shaft body is made of a metal material, and the shaft cap is made of a nonmetallic material.
A second aspect of an embodiment of the present invention provides a method for using a carrier head, where the method includes:
s1, a bearing head moves to the upper part of a wafer to be sucked, and an elastic film is sequentially pressurized from the center to the edge, so that the wafer is abutted to the lower part of the elastic film;
s2, vacuumizing a detection chamber of the elastic membrane and a chamber at the inner side of the detection chamber, so that the wafer is sucked and moves upwards;
s3, the upward wafer pushes the pin shaft of the detection assembly to move, so that the auxiliary chamber is communicated with the detection chamber, and the detection chamber is communicated with the judgment chamber of the elastic membrane through the auxiliary chamber; based on the pressure change of the judging chamber, whether the wafer is attracted under the elastic membrane is judged.
A third aspect of an embodiment of the present invention provides a chemical mechanical polishing system, comprising a polishing platen, a liquid supply device for supplying a polishing liquid toward a space between the polishing platen and a wafer, a dressing device for dressing a surface of the polishing platen, and the carrier head described above, the carrier head carrying a wafer to be polished and abutting the wafer against the polishing platen.
The beneficial effects of the invention include:
a. a detection assembly is arranged in the bearing head, and the sucked wafer can push the pin shaft to move vertically, so that whether the wafer is sucked or not is judged by changing the on-off state of the cavity;
b. the configured detection assembly is a mechanical sensor, and devices such as a power supply and the like are not required to be additionally configured, so that the stability of the detection of the bearing head is effectively ensured;
c. the outer peripheral wall of the lower shaft section of the pin shaft is provided with a concave part, the inner side wall of the bearing disc vent hole is provided with a convex part, and the shape and the size of the concave part are matched with those of the convex part, so that the pin shaft is prevented from deflecting in the moving process, and the running stability of the detection assembly is ensured;
d. the fixing piece of the detection assembly is configured to limit the limiting hole or the circular convex column of the elastic piece so as to prevent the elastic piece from shifting and ensure the stable operation of the detection assembly.
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 carrier head for chemical mechanical polishing according to one embodiment of the present invention;
FIG. 2 is a schematic view of a carrier tray according to an embodiment of the present invention;
FIG. 3 is an enlarged view of a portion of FIG. 1 at A;
FIG. 4 is a schematic view of a pin according to an embodiment of the present invention;
FIG. 5 is a schematic view of a pin according to another embodiment of the present invention;
FIG. 6 is a partial schematic view of the carrier platter corresponding to FIG. 5;
FIG. 7 is a schematic view of a pin according to yet another embodiment of the present invention;
FIG. 8 is a partial schematic view of the carrier platter corresponding to FIG. 7;
FIG. 9 is a schematic view of a pin provided by another embodiment of the present invention;
FIG. 10 is a cross-sectional view of a fastener provided in an embodiment of the present invention;
FIG. 11 is a cross-sectional view of a fastener provided in another embodiment of the present invention;
FIG. 12 is a flow chart of a method of using a carrier head provided by the present invention;
FIG. 13 is a schematic diagram of the detection chamber and the determination chamber corresponding pressures before loading a wafer by the carrier head;
FIG. 14 is a schematic diagram of the detection chamber and the determination chamber corresponding pressures after loading the wafer by the carrier head;
FIG. 15 is a schematic view of a chemical mechanical polishing system according to one 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) units used in the semiconductor device manufacturing industry, in which a polishing liquid composed of submicron or nano abrasive particles and a chemical solution flows between a wafer and a polishing pad, the polishing liquid is uniformly distributed under the action of a transmission and rotation centrifugal force of the polishing pad to form a liquid film between the wafer and the polishing pad, chemical components in the liquid chemically react with the wafer to convert insoluble substances into soluble substances, and then the chemical reactants are removed from the wafer surface by micro-mechanical friction of the abrasive particles and taken away in the flowing liquid, i.e., surface materials are removed during an alternating process of chemical film formation and mechanical film removal, thereby achieving a global planarization.
Fig. 1 is a schematic view of a carrier head 100 for chemical mechanical polishing according to an embodiment of the present invention, where the carrier head 100 includes:
a main body 10 having a disk-like structure, wherein a body groove 11 is provided in an upper portion of the main body 10;
an elastic membrane 20 connected to the lower side of the main body 10 through a carrier plate 30; the elastic membrane 20 is a flexible member made of rubber, which is in direct contact with the wafer to load the wafer. I.e., the carrier head 100 is capable of sucking a wafer to be polished to the bottom of the elastic membrane 20. The elastic membrane 20 is internally provided with a partition plate to divide the elastic membrane 20 into a plurality of chambers, thereby realizing loading of wafers and controlling application of polishing load. In the embodiment shown in fig. 1, the elastic membrane 20 is divided into chambers C1, C2, C3, C4 and C5.
Further, the carrier head 100 further includes a gas distribution seat 40 connected to the upper side of the main body 10 through a diaphragm 50; specifically, the air distribution seat 40 has a disc-shaped structure, and is concentrically arranged in the base groove 11;
the carrier head 100 further includes a retaining ring 60 disposed below the main body 10 and located at the outer peripheral side of the elastic membrane 20 to define a wafer sucked under the elastic membrane 20, preventing the polished wafer from sliding out between the retaining ring 60 and the polishing pad;
further, a connecting flange 70 is disposed above the air distribution seat 40, and the connecting flange 70 is connected with a driving device (not shown) above to drive the bearing head 100 to rotate around the central axis; the driving device comprises a rotary joint, so that a plurality of pipelines are connected with air holes on the connecting flange 70 through the rotary joint, meanwhile, the connecting flange 70 is combined with the air distribution seat 40, and fluid in the pipelines is respectively supplied to each cavity of the elastic membrane 20, so that the loading and unloading piece of the elastic membrane 20 and the application of load are controlled.
In the embodiment shown in fig. 1, the carrier head 100 further includes a detecting assembly 80 disposed in the mounting hole 31 (shown in fig. 2) of the carrier plate 30, and the detecting assembly 80 corresponds to one of the chambers of the elastic membrane 20 to detect whether the wafer is sucked to the lower portion of the elastic membrane 20. For convenience of description, the chambers of the elastic membrane 20 corresponding to the detection assembly 80 are collectively referred to as detection chambers.
As shown in fig. 2, a schematic view of a carrier plate 30 according to an embodiment of the present invention is shown, and a mounting hole 31 is disposed at an upper portion of the carrier plate 30.
Further, the mounting hole 31 is provided therein with a concentric vent hole 32, and the vent hole 32 penetrates the carrier plate 30 in the thickness direction. Namely, the mounting hole 31 and the vent hole 32 form a stepped hole at the upper portion of the carrier tray 30 so as to mount the stationary detection assembly 80.
Further, the detecting assembly 80 includes a pin 81, a sealing member 82, an elastic member 83, and a fixing member 84, as shown in fig. 3, the pin 81 is disposed at the vent hole 32 of the carrier plate 30 with a gap therebetween, so that the pin 81 can move along the center line of the vent hole 32.
Specifically, the seal 82 and the elastic member 83 are fitted around the outer peripheral side of the pin 81; further, a sealing member 82 is provided at the bottom of the mounting hole 31, and an elastic member 83 is provided at the upper portion of the pin shaft 81.
The fixing member 84 is a cover-like structure, which is sealingly connected above the mounting hole 31. Meanwhile, the bottom of the fixing member 84 is configured with a blind hole 84a, and as shown in fig. 3, the elastic member 83 abuts against the top of the blind hole 84a. Specifically, a seal groove is disposed on the top surface of the bearing disc 30, the seal groove is concentrically disposed on the outer peripheral side of the mounting hole 31, and a seal ring is disposed in the seal groove; the fixing member 84 can press the sealing ring and fix to the upper side of the carrier plate 30 to sealingly connect the fixing member 84 to the upper side of the carrier plate 30.
Since the fixing member 84 is pressed against the end of the elastic member 83, the elastic member 83 is in a compressed state, which can push the pin 81 against the sealing member 82, so that the fixing member 84 and the mounting hole 31 form a sealed auxiliary chamber C a 。
As an embodiment of the present invention, the bottom surface of the mounting hole 31 is provided with a mounting groove, the longitudinal section of the mounting groove is rectangular, and the sealing member 82 is disposed in the mounting groove, so as to prevent the sealing member 82 from moving left and right, and ensure the stability of the use of the detecting assembly 80.
It should be noted that, the size of the mounting groove is slightly larger than that of the sealing member 82, so as to avoid the pin 81 from tilting due to the pin 81 being clamped at the edge of the mounting groove after being returned.
In the embodiment shown in fig. 3, at least part of the pin 81 is located in the cavity C2 (shown in fig. 1) of the elastic membrane 20, i.e. the cavity C2 measures the cavity C d The method comprises the steps of carrying out a first treatment on the surface of the After the wafer is sucked by the elastic film 20, the wafer and the bottom plate portion 21 of the elastic film 20 can push the pin shaft 81 to move in the vertical direction. After the pin 81 moves upward, the pin 81 no longer presses the seal 82 thereunder, i.e., the seal 82 changes from the pressed state to the relaxed state. Fluid, such as gas, in chamber C2 can enter auxiliary chamber C through the gap between pin 81 and vent hole 32 a In such a way that the detection chamber C d And auxiliary chamber C a Is communicated with each other.
While assisting the chamber C a Determination chamber C with elastic membrane 20 through the provided piping or tubing j Communicate with, if the auxiliary chamber C a Communicate with the chamber C2, the chamber C is determined j Will be equal to the pressure of chamber C2. I.e. by taking the decision chamber C j The state of the pin 81 is known, and whether the wafer is sucked to the lower portion of the elastic film 20 is determined.
In the embodiment shown in FIG. 3, chamber C is determined j Is chamber C3, which adjoins chamber C2. If the wafer is sucked to the lower portion of the elastic membrane 20, the pins 81 are moved upward to make the chamber C2 and the auxiliary chamber C a Is communicated with each other. Due to the auxiliary chamber C a And determination chamber C j Communication, the pressure of chamber C3 is equal to the pressure of chamber C2. I.e. by determining chamber C j To determine whether the wafer is sucked to the lower portion of the carrier head 100.
Fig. 4 is a schematic diagram of a pin shaft 81 according to an embodiment of the present invention, where the pin shaft 81 includes an upper shaft section 81a, a lower shaft section 81b, and a shaft shoulder 81c, and the shaft shoulder 81c is disposed between the upper shaft section 81a and the lower shaft section 81b, and the three are integrally formed.
Further, an elastic member 83 is disposed on the outer peripheral side of the upper shaft section 81a, and as shown in fig. 3, a shoulder 81c is provided in the mounting hole 31, and a seal 82 is fitted over the lower shaft section 81b and is located below the shoulder 81c. I.e., the seal 83 is disposed between the shoulder 81c and the bottom surface of the mounting hole 31.
The lower shaft section 81b is coaxially and intermittently disposed in the vent hole 32 such that the pin 81 can move in the direction of the center axis of the vent hole 32.
As an aspect of the present embodiment, a gap between the lower shaft section 81b and the inner side wall of the vent hole 32 is not more than 0.2mm to ensure that the pin shaft 81 can smoothly move along the central axis of the vent hole 32.
The gap between the pin 81 and the vent hole 32 should not be too large. If the gap between the pin 81 and the vent hole 32 is too large, the pin 81 may incline during the upward movement, which may cause the upper end of the pin 81 to be clamped with the elastic member 83 and not reset, thereby affecting the accuracy of the determination of the detection assembly 80. In addition, the pin 81 is in an inclined state, and the edge of the end of the pin directly contacts the elastic membrane 20 and indirectly abuts against the wafer, so that the wafer is broken due to local stress of the wafer.
Preferably, the gap between the pin 81 and the inner side wall of the vent hole 32 is 0.01-0.1mm, so that the pin 81 is prevented from tilting to influence the normal judgment of the detection assembly 80 and avoid the occurrence of fragments on the premise of ensuring smooth movement of the pin 81.
Fig. 5 is a schematic view of a pin 81 according to an embodiment of the present invention, in which a recess 81d is disposed on an outer peripheral side of a lower shaft section 81b, and the recess 81d is disposed along a length direction of the pin 81. Specifically, the recess 81d extends from the end of the lower shaft section 81b to the shoulder 81c.
Fig. 6 is a partial top view of a carrier plate 30 according to an embodiment of the present invention, which shows the general structure of the mounting holes 31 and the ventilation holes 32. Specifically, the inner side wall of the vent hole 32 is provided with a protrusion 32a, and the protrusion 32a penetrates in the thickness direction of the carrier plate 30.
Further, the concave portion 81d of the pin 81 is matched with the shape and size corresponding to the convex portion 32a of the vent hole 32, so as to prevent the pin 81 from tilting during the moving process to influence the judgment of whether the wafer is sucked or not. It should be noted that a protruding structure may be provided on the pin 81, and a recessed structure may be provided on the inner side wall of the vent hole 32, as long as the protruding structure and the recessed structure are matched with each other.
In the present invention, at least one of the number of concave portions 81d on the outer peripheral side of the pin shaft 81, and accordingly, the number of convex portions 32a on the carrier tray 30 is equal to the number of concave portions 81d of the pin shaft 81. In the embodiment shown in fig. 5, the number of concave portions 81d is 6, which are uniformly distributed along the outer peripheral side of the lower shaft section 81 b; it will be appreciated that the recess 81d may be other numbers, such as 5 pieces, 8 pieces, 12 pieces, etc.
In fig. 5, the cross-sectional shape of the concave portion 81d is semicircular, and the cross-sectional shape of the convex portion 32a of the vent hole 32 is semicircular accordingly. It will be appreciated that the cross-sectional shape of recess 81d may also be rectangular, triangular and/or dovetail.
Fig. 7 is a schematic view of a pin shaft 81 according to another embodiment of the present invention, in which a recess 81d is provided on the outer peripheral side of a lower shaft section 81b, and the cross-sectional shape of the recess 81d is a dovetail shape; fig. 8 is a partial schematic view of the carrier plate 30, on which the protrusions 32a are arranged on the inner side walls of the ventilation holes 32, and the cross-sectional shape of the protrusions 32a is also dovetail-shaped. By the arrangement, the pin shaft 81 can be ensured to vertically move in the vent hole 32, and the phenomenon that the normal use of the detection assembly 80 is influenced due to the large deflection of the pin shaft 81 is avoided.
As an embodiment of the present invention, the pin shaft 81 may be made of a metal material such as stainless steel, titanium alloy, or the like. Because the pin shaft 81 is disposed inside the carrier head 100, the pin shaft 81 is not exposed outside the carrier head 100 during polishing, and thus metal ion pollution is not generated.
In some embodiments, the pin 81 may also be made of a non-metallic material, such as polytetrafluoroethylene, nylon, etc., to control the stiffness of the pin 81, particularly the lower shaft section 81 b; this prevents the end of the pin 81 from being rigidly abutted against the bottom plate portion 21 of the elastic film 20 to some extent.
Fig. 9 is a schematic view of a pin 81 according to another embodiment of the present invention, which adopts a split structure. Specifically, the pin shaft 81 includes a shaft body 81e and a shaft cap 81f, and the shaft body 81e is detachably connected to the shaft cap 81f; wherein the shaft body 81e is made of a metallic material and the shaft cap 81f is made of a nonmetallic material. I.e., the upper portion of the pin shaft 81 is made of a metal material and the lower portion of the pin shaft 81 is made of a non-metal material, to prevent the pin shaft 81 from tilting to scratch the bottom plate portion 21 of the elastic membrane 20.
In the present invention, the fixing member 84 is provided with a blind hole 84a in which the elastic member 83 is placed. To prevent the spring 83 from shifting in the blind hole 84a. A limiting hole 84b is disposed on the top surface of the blind hole 84a, as shown in fig. 10, the upper end of the elastic member 83 is clamped to the limiting hole 84b, so as to effectively limit the position of the elastic member 83, and effectively prevent the elastic member 83 from moving in position to affect the normal use of the detection assembly 80.
As a modification of the embodiment of fig. 10, a circular boss 84c may be disposed on the top surface of the blind hole 84a, and as shown in fig. 11, the inner ring of the elastic member 83 may be fitted around the outer periphery of the circular boss 84c, so that the elastic member 83 may be prevented from being displaced, thereby achieving the same function.
Meanwhile, the invention also discloses a using method of the bearing head, a flow chart of which is shown in fig. 12, wherein the using method of the bearing head comprises the following steps:
s1, the bearing head 100 moves to the upper part of a wafer to be sucked, and the elastic film 20 is sequentially pressurized from the center to the edge, so that the wafer is abutted to the lower part of the elastic film 20;
specifically, the carrier head 100 is moved above a loading device (load cup), at this time, a wafer is placed inside the loading device, and a carrier of the loading device is moved upward so that the wafer contacts the bottom of the elastic membrane; then, the carrier head 100 controls the pressure of each chamber of the elastic membrane 20, so that the elastic membrane 20 is sequentially pressurized from the central chamber to the edge chamber, so as to discharge the air, water and other fluids between the elastic membrane 20 and the wafer, and the wafer is tightly attached to the lower part of the elastic membrane 20.
S2, detection chamber C of elastic membrane 20 d The inner chamber is vacuumized, so that the wafer is sucked and moves upwards;
typically, the detection chamber C d Is a non-central chamber of the elastic membrane 20, i.e. the detection chamber C d Between the central chamber and the edge chamber. In step S2, the detection chamber C d And the chambers inside the same are evacuated, so that the corresponding areas of the elastic membrane 20 attract the wafer W, while the other chambers of the elastic membrane 20 are in vent state. At this time, the chamber C is detected d Is negative, such as-3 psi; while the other chambers have a pressure of 0psi, i.e. determination chamber C j Is 0 as shown in fig. 13.
In the present invention, during the vacuum pumping operation of the corresponding chambers of the elastic membrane 20, the chambers are sequentially evacuated from the center of the elastic membrane 20 to the outside until the chambers are evacuated to the detection chamber C d So that the wafer is sucked to the lower portion of the elastic membrane 20. In the embodiment shown in FIG. 1, the detection chamber is C3, detection chamber C d The inner chambers have: chamber C4 and chamber C5. During the evacuation operation, the chamber C5, the chamber C4 and the chamber C3 need to be evacuated in sequence, so that the carrier head completes the suction action of the wafer through the elastic membrane 20.
S3, the upward wafer pushes the pin 81 of the detection assembly 80 to move, so that the chamber C is assisted a And detection chamber C d Is communicated with a detection chamber C d Through the auxiliary chamber C a Determination chamber C with elastic membrane 20 j Is communicated with each other; based on determination chamber C j And judging whether the wafer is attracted under the elastic membrane or not.
Specifically, the elastic membrane 20 moves upward after sucking the wafer, and can push the pin 81 to move in the vertical direction, and after the pin 81 moves upward, the sealing member 82 under the shoulder 81C changes from a compressed state to a relaxed state, and at this time, the chamber C is assisted a And detection chamber C d Is communicated with each other.
Due to the assistanceAuxiliary chamber C a Determination chamber C with elastic membrane 20 j Is communicated with, then determine the chamber C j Will be equal to the pressure of the detection chamber C d Is a pressure of the pressure sensor. I.e. determination chamber C j The pressure of (2) is changed from 0 to a negative value. As shown in fig. 14. If this occurs, the carrier head 100 successfully suctions the wafer under the elastic membrane 20.
If it is determined that chamber C j The pressure of (2) is still 0, then the auxiliary chamber C is described a And detection chamber C d Not connected, i.e., pins 81 are not moved upward, carrier head 100 is not successful in sucking a wafer.
In the present invention, the pin 81 of the detecting unit 80 is provided with the concave portion 81d, and the inner wall of the vent hole 32 of the carrier head 30 is provided with the convex portion 32a. The arrangement can ensure that the pin shaft 81 moves along the vertical direction, and the normal judgment of the detection assembly 80 is prevented from being influenced by the deflection of the pin shaft 81.
In addition, the present invention also discloses a chemical mechanical polishing system 1000, as shown in fig. 15, which includes a polishing platen 300, a dressing apparatus 400, a liquid supply apparatus 500, and the carrier head 100 described above. A polishing pad 200 is disposed above the polishing platen 300, and the polishing pad 200 and the polishing platen 300 are wound around A x The shafts rotate together. The carrier head 100 capable of horizontally moving is arranged above the polishing pad 200, and the bottom of the carrier head 100 is sucked with a wafer to be polished; the dressing part 400 swings around a fixed point, and the dressing head configured thereon rotates itself and applies a downward load to dress the surface of the polishing pad 200; the liquid supply part 500 is disposed above the polishing pad 200 to spread the polishing liquid on the surface of the polishing pad 200.
During polishing operation, the carrier head 100 abuts the surface to be polished of the wafer against the surface of the polishing pad 200, and the carrier head 100 performs rotary motion and reciprocating motion along the radial direction of the polishing disc 300, so that the surface of the wafer contacting the polishing pad 200 is gradually polished; while the polishing platen 300 is rotated, the liquid supply part 500 sprays the polishing liquid to the surface of the polishing pad 200 to supply the polishing liquid between the wafer and the polishing pad 200. Under the chemical action of the polishing liquid, the wafer and the polishing pad are rubbed by the relative motion of the carrier head 100 and the polishing disk 300 to achieve global polishing.
The cmp system 1000 shown in fig. 15 includes the carrier head 100 described above, and the embryo cloth is configured with the mechanical detecting assembly 80 to determine whether the wafer is sucked or not through the pressure change of the chamber, so as to effectively ensure the reliability of the detection of the carrier head 100.
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 (12)

1. A carrier head for chemical mechanical polishing, comprising:
a main matrix;
an elastic membrane connected to the lower side of the main base body through a carrying disc;
the detection assembly is arranged in the mounting hole of the bearing disc and corresponds to one cavity of the elastic membrane, and the corresponding cavity of the detection assembly is a detection cavity;
the detection assembly comprises a pin shaft, a sealing element, an elastic element and a fixing element, wherein the pin shaft is arranged in a vent hole of the bearing disc in a clearance mode, the sealing element and the elastic element are sleeved on the periphery side of the pin shaft, the sealing element is arranged at the bottom of the mounting hole, the elastic element is arranged at the upper part of the pin shaft, and the fixing element is connected above the mounting hole in a sealing mode and is abutted to the upper end of the elastic element; the compressed elastic piece can push the pin shaft to press the sealing piece, so that the fixing piece and the mounting hole form a sealed auxiliary chamber; at least part of the pin shaft is positioned in the detection chamber and can move vertically so as to change the on-off state of the auxiliary chamber and the detection chamber.
2. The carrier head of claim 1, wherein the wafer held by the elastic membrane is capable of pushing the pin to move upward so that the auxiliary chamber is in communication with the inspection chamber; the auxiliary chamber is communicated with the judging chamber of the elastic membrane, so that the pressure of the detecting chamber is equal to the pressure of the judging chamber.
3. The carrier head of claim 1, wherein the pin shaft comprises an upper shaft section, a lower shaft section and a shaft shoulder positioned therebetween, an elastic member is arranged on the outer peripheral side of the upper shaft section, a sealing member is arranged between the shaft shoulder and the bottom surface of the mounting hole, and the lower shaft section is coaxially arranged in the vent hole.
4. A carrier head according to claim 3, wherein the outer peripheral side of the lower shaft section is provided with a recess provided along the length direction of the pin shaft; the inner side wall of the vent hole is provided with a convex part which is penetrated along the thickness direction of the bearing plate; the recess matches the shape and size of the protrusion.
5. The carrier head of claim 4, wherein the number of recesses is a plurality, which are evenly distributed along the lower shaft section.
6. The carrier head of claim 4, wherein the recess has a semi-circular, rectangular, triangular, and/or dovetail cross-sectional shape.
7. The carrier head of claim 1, wherein the gap between the pin and the vent is no greater than 0.2mm.
8. The carrier head of claim 1, wherein a blind hole for placing the elastic member is disposed below the fixing member, a limiting hole is disposed on the top surface of the blind hole, and the upper end of the elastic member is clamped in the limiting hole.
9. The carrier head of claim 1, wherein the pins are made of a metallic material or a non-metallic material.
10. The carrier head of claim 1, wherein the pin shaft comprises a shaft body and a shaft cap, the shaft body being detachably connected to the shaft cap; the shaft body is made of a metal material, and the shaft cap is made of a nonmetallic material.
11. A method of using a carrier head according to any one of claims 1 to 10, comprising:
s1, a bearing head moves to the upper part of a wafer to be sucked, and an elastic film is sequentially pressurized from the center to the edge, so that the wafer is abutted to the lower part of the elastic film;
s2, vacuumizing a detection chamber of the elastic membrane and a chamber at the inner side of the detection chamber, so that the wafer is sucked and moves upwards;
s3, the upward wafer pushes the pin shaft of the detection assembly to move, so that the auxiliary chamber is communicated with the detection chamber, and the detection chamber is communicated with the judgment chamber of the elastic membrane through the auxiliary chamber; based on the pressure change of the judging chamber, whether the wafer is attracted under the elastic membrane is judged.
12. A chemical mechanical polishing system comprising a polishing platen, a liquid supply device for supplying a polishing liquid toward between the polishing platen and a wafer, a dressing device for dressing a surface of the polishing platen, and the carrier head according to any one of claims 1 to 10, which carries a wafer to be polished and abuts against the polishing platen.
CN202310739537.9A 2023-06-21 2023-06-21 Carrier head for chemical mechanical polishing and application method thereof Pending CN116512114A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310739537.9A CN116512114A (en) 2023-06-21 2023-06-21 Carrier head for chemical mechanical polishing and application method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310739537.9A CN116512114A (en) 2023-06-21 2023-06-21 Carrier head for chemical mechanical polishing and application method thereof

Publications (1)

Publication Number Publication Date
CN116512114A true CN116512114A (en) 2023-08-01

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310739537.9A Pending CN116512114A (en) 2023-06-21 2023-06-21 Carrier head for chemical mechanical polishing and application method thereof

Country Status (1)

Country Link
CN (1) CN116512114A (en)

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