A carrier head for chemical mechanical polishing and chemical mechanical polishing equipment

Abstract

The present invention relates to the technical field of post-processing of chemical mechanical polishing, and discloses a carrier head for chemical mechanical polishing, comprising a coupling plate, a balancing frame, a carrier plate, and a flexible membrane, wherein the balancing frame has a central axis portion and a chassis portion formed at the bottom end of the central axis portion, the central axis portion can be slidably arranged in the central through hole of the coupling plate, and the chassis portion is connected to the carrier plate to drive the carrier plate to move up and down relative to the coupling plate, a portion of the flexible membrane is clamped to the lower part of the carrier plate to form a sealed chamber, and a wave-absorbing layer is arranged on the lower surface of the chassis portion.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical mechanical polishing, and in particular to a carrier head and chemical mechanical polishing equipment used for chemical mechanical polishing. Background Art

[0002] Chemical mechanical polishing is a mainstream substrate polishing method in the field of chip manufacturing. This polishing method usually involves sucking the substrate under the carrier head, with the side of the substrate with the deposition layer abutting against the rotating polishing pad. The carrier head rotates in the same direction as the polishing pad under the drive of the driving component and applies a downward load to the substrate; at the same time, the polishing liquid is supplied to the upper surface of the polishing pad and distributed between the substrate and the polishing pad, so that the substrate is globally polished under the combined action of chemistry and mechanics.

[0003] The carrier head is an important component of the chemical mechanical polishing device, and its operating performance is directly related to the chemical mechanical polishing effect of the substrate. For example, US Patent US20130065495A1 discloses a carrier head, which includes a carrier plate and an elastic membrane, and the elastic membrane is detachably arranged at the lower part of the carrier plate; the carrier plate includes a first part and a second part, and the first part is movably and concentrically arranged in the upper groove of the second part so that the first part and the second part can move relative to each other in a direction perpendicular to the bottom surface of the carrier plate. An elastic membrane is installed at the lower part of the second part so that a plurality of air cavities are formed between the second part and the elastic membrane to adjust the pressure profile of the substrate by adjusting the pressure of each independent air cavity. In the prior art, external air enters the channel inside the first part through the air holes on the upper surface of the first part and flows out from the air holes on the side wall of the first part, and then is transported to the air holes on the upper surface of the second part respectively connected with the independent air cavities through the air pipe.

[0004] Chinese patent CN104854680B discloses a carrier head that can clamp the tail ends of each baffle between clamping plates. The various clamping plates can be substantially pure plastic, composite plastic, or metal, the pure plastic is such as polyetheretherketone or polyphenylene sulfide, the composite plastic is such as glass-filled or glass-filled PEEK, and the metal is such as stainless steel or aluminum. The ring frame mechanism allows the base assembly to slide vertically relative to the shell while limiting the lateral movement of the base assembly. The outer cover is made of, for example, semi-crystalline thermoplastic polyester based on polyethylene terephthalate, for example, polyester can be covered on the outside of the base assembly to prevent contamination from the slurry from reaching the interior of the carrier head.

[0005] However, as the size of the characteristic structure of electronic devices continues to shrink, the manufacturing process has higher and higher requirements for the process of chemical mechanical polishing, resulting in more and more gas chamber partitions in the carrier head. This makes the structure of the carrier head increasingly complex, and the number of parts and the combination relationship have reached an unprecedented level of complexity, which has brought challenges to assembly and maintenance operations, and has put forward very high precision and cost requirements for parts processing; in addition, the detection accuracy requirements of chemical mechanical polishing endpoint detection have also increased with the continuous reduction of the size of the characteristic structure, so certain requirements are also put forward for the overall electromagnetic signal reflection performance of the carrier head, hoping that when measuring the thickness of the metal structure feature on the substrate, other metal parts on the carrier head can reflect the electromagnetic measurement signal as little as possible; not only that, it is also required that the carrier head quickly pick up and place the substrate and reduce the possible impact on the substrate during the process of pressurizing the substrate to prevent damage to the substrate.

[0006] In summary, it is desirable to provide a polishing apparatus with more precise and more uniform chemical mechanical polishing. Summary of the invention

[0007] The embodiments of the present invention provide a carrier head and a chemical mechanical polishing device for chemical mechanical polishing, aiming to solve one of the technical problems existing in the prior art to at least a certain extent.

[0008] A first aspect of an embodiment of the present invention provides a carrier head for chemical mechanical polishing, including a coupling plate, a balance frame, a carrier plate, and a flexible membrane, wherein the balance frame has a central axis portion and a chassis portion formed at the bottom end of the central axis portion, the central axis portion is slidably disposed in a central through hole of the coupling plate, and the chassis portion is connected to the carrier plate to drive the carrier plate to move up and down relative to the coupling plate, a portion of the flexible membrane is clamped to the lower portion of the carrier plate to form a sealed chamber, and a wave-absorbing layer is provided on the lower surface of the chassis portion.

[0009] Preferably, the carrier head has an annular pressure plate, the flexible membrane has an annular edge wrinkle extending upward along its bottom surface and at least one annular inner wrinkle wall arranged concentrically with the edge wrinkle wall, and the innermost inner wrinkle wall among the inner wrinkles and at least one of the edge wrinkles are clamped and fixed to the lower surface of the carrier plate by the annular pressure plate.

[0010] Preferably, the wave-breaking layer is formed of at least one of Permalloy, ferrite, barium titanate, silicon carbide, graphite, metal powder, conductive fiber and / or chiral material.

[0011] Preferably, the wave-breaking layer is fixed to the lower surface of the chassis portion by electroplating, spraying, pasting, coating or vapor deposition.

[0012] Preferably, the material of the balance frame is a metal material with a relative magnetic permeability not exceeding 304 austenitic stainless steel.

[0013] Preferably, a central area of ​​the chassis portion of the balance frame has a downwardly extending convex structure.

[0014] Preferably, the downward convex structure extends downward in the vertical direction to a level not lower than the lower surface of the annular pressure plate.

[0015] Preferably, the downwardly convex structure is a truncated cone formed of a non-metallic material, and the truncated cone is fixedly bonded to the bottom of the balance frame by an adhesive.

[0016] Preferably, the thickness of the wave-breaking layer is 0.03 mm to 2 mm.

[0017] A second aspect of an embodiment of the present invention provides a chemical mechanical polishing device, wherein the chemical mechanical polishing device comprises the carrier head described above.

[0018] The carrier head and chemical mechanical polishing equipment for chemical mechanical polishing described in the present application have the following beneficial effects: improving and enhancing the accuracy of film thickness measurement during the polishing process without affecting the operating function and reliability of the carrier head and chemical mechanical polishing equipment, thereby improving the accuracy of the polishing process control and the polishing results. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The advantages of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings, but these drawings are only schematic and do not limit the scope of protection of the present invention, wherein:

[0020] Figure 1 is a schematic structural diagram of a carrier head 1 for chemical mechanical polishing according to the present invention;

[0021] Figure 2 is a schematic structural diagram of a balancing frame 11 according to the present invention;

[0022] Figure 3 It is a schematic diagram of the structure of the coupling plate 12 according to the present invention;

[0023] Figure 4 is a schematic structural diagram of a carrier plate 13 according to the present invention;

[0024] Figure 5 is a schematic diagram of the structure of the flexible membrane 14 according to the present invention;

[0025] Figure 6 A schematic diagram showing a film thickness measuring device 203 for measuring the thickness of a metal film layer 202 on a substrate 201 and a carrier head 1 according to the present invention is shown;

[0026] Figure 7 is a schematic diagram of the installation of a balancing frame with a wave-breaking layer in the carrier head 1;

[0027] Figure 8 is a schematic structural diagram of another embodiment of the balancing frame 11 according to the present invention;

[0028] Fig. 9 is a structural schematic diagram of another embodiment of the balance frame 11 according to the present invention;

[0029] Fig.10 yes Fig. 9 The schematic diagram of the installation of the balance frame 11 in the carrier head 1 is shown. DETAILED DESCRIPTION

[0030] The technical scheme of the present invention is described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limitations on the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical schemes based on the contents disclosed in the claims of this application and its specification, and these technical schemes include technical schemes that adopt any obvious replacements and modifications to the embodiments recorded herein. It should be understood that, unless otherwise specified, for ease of understanding, the following descriptions of the specific embodiments of the present invention are all based on the description of the relevant equipment, devices, components, etc. in the original static natural state without external control signals and driving forces.

[0031] An embodiment of a carrier head 1 for chemical mechanical polishing according to the present invention is as follows: Figure 1 As shown, it includes a balance frame 11, a coupling plate 12, a bearing plate 13, a flexible film 14 and an annular pressure plate 15; a first clamping ring 20 clamps the outer edge of the annular elastic film 21 to the bearing plate 13 and a second clamping ring 23 clamps the inner edge of the annular elastic film 21 to the coupling plate 12, so that when the coupling plate 12 rotates with an external drive shaft (not shown), the coupling plate 12 can drive the bearing plate 13 to rotate coaxially through the annular elastic film 21; a third clamping ring 18 and annular gaskets 17A, 1 7B clamps the balance frame 11 to the carrier plate 13, and the annular pressure plate 15 clamps the flexible membrane 14 to the lower part of the carrier plate 13 in an airtight manner so that the flexible membrane 14 can rotate coaxially with the carrier plate 13 and the balance frame 11 and move up and down in the vertical direction relative to the coupling plate 12; the retaining ring 16 is fixedly coupled to the lower surface of the carrier plate 13; when the carrier head 1 is operating, the coupling plate 12 is coupled to the external drive shaft, and the substrate to be processed is received and retained under the flexible membrane 14 on the inner side of the retaining ring 16.

[0032] like Figure 2As shown, the balancing frame 11 is composed of a vertically extending middle axis portion 111, a chassis portion 112, a peripheral wall portion 113 and a flange portion 114. The disc-shaped chassis portion 112 is coaxially formed at the bottom of the middle axis portion 111 and its radius is at least 3 times the radius of the middle axis portion 111. The peripheral wall portion 113 extends vertically upward along the circumferential edge of the chassis portion 112 to no more than half the height of the middle axis portion 111 to form a semi-closed annular cylindrical stroke cavity 116 with a certain height. The annular flat flange portion 114 is formed by horizontally extending outward from the upper outer surface of the peripheral wall portion 113 and its thickness is greater than or equal to the thickness of the chassis portion 112 and / or the peripheral wall portion 113. In addition, the middle axis portion 111 has a first through hole 115 arranged along its axis and extending from the upper surface of the middle axis portion 111 to the lower surface of the chassis portion 112. An external gas source not shown can introduce 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.

[0033] like Figure 3 As shown in FIG. 1 , the coupling plate 12 is composed of a cylindrical main body 121 and a peripheral portion 122. The main body 121 has a second through hole 123 extending along its central rotation axis and serving as an axial hole, and at least one third through hole 124 extending parallel to the second through hole 123. The second through hole 123 is the central through hole. The outer diameter of the main body 121 is slightly smaller than the inner diameter of the cylindrical stroke chamber 116, so that Figure 1 As shown, when the coupling plate 12 moves downward relative to the balancing frame 11, the main body 121 of the coupling plate 12 can be inserted downward into the cylindrical stroke cavity 116 of the balancing frame 11, and the inner diameter of the second through hole 123 matches the outer diameter of the middle axis portion 111 of the balancing frame 11 so that the middle axis portion 111 can be slidably inserted into the second through hole 123 and slide airtightly therein in the vertical direction; in other words, the balancing frame 11 cooperates with the second through hole 123 of the coupling plate 12 via its middle axis portion 111, and can move vertically up and down along their common central rotation axis.

[0034] like Figure 4 As shown, the carrier plate 13 is a disk with a certain thickness, which has a stepped hole 131 extending through the central rotation axis, and the stepped hole 131 is composed of a first stepped hole 131A, a second stepped hole 131B, a third stepped hole 131C and a fourth stepped hole 131D, wherein the radii of the four stepped holes are different and increase from bottom to top. The inner diameter of the first stepped hole 131A is slightly larger than the outer diameter of the bottom plate portion 112 of the balance frame 11, the radius of the second stepped hole 131B is slightly larger than the distance between the outer end of the flange portion 114 and the central rotation axis, and the inner diameter of the fourth stepped hole 131D is 1 to 20 mm larger than the outer diameter of the peripheral portion 122 of the coupling plate 12, so that Figure 1As shown, the balance frame 11 is clamped and fixed to the step hole 131 by the annular gaskets 17A, 17B and the third clamping ring 18 to form a relatively closed first pressure chamber 25 with variable volume, which is composed of the inner surface of the cylindrical stroke cavity 116, the inner surface and upper surface of the third clamping ring 18, the bottom and side surfaces of the fourth step hole 131D, the lower surface of the annular elastic membrane 21, the lower surface and outer surface of the second clamping ring 23, and the lower surface of the coupling plate 12 not covered by the second clamping ring 23.

[0035] like Figure 1 As shown, when gas is introduced into the first pressure chamber 25 through the third through hole 124, the gas pressure in the first pressure chamber 25 increases, so that the combined balance frame 11 and the supporting plate 13 move downward in the vertical direction as a whole relative to the coupling plate 12, and the volume of the first pressure chamber 25 increases accordingly; similarly, when gas is extracted from 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 frame 11 and the supporting plate 13 move upward in the vertical direction as a whole relative to the coupling plate 12, and the volume of the first pressure chamber 25 decreases accordingly, and the vertical movement of the balance frame 11 and the supporting plate 13 drives the movement of the flexible membrane 14 and the annular pressure plate 15 to actuate and / or hold the substrate.

[0036] Further, such as Figure 1 and Figure 3 As shown, the lower edge of the peripheral portion 122 of the coupling plate 12 has an edge recess 231 for accommodating the second clamp ring 23, and the depth of the edge recess 231 is configured so that when the second clamp ring 23 and the third clamp ring 18 are respectively fixed to the coupling plate 12 and the supporting plate 13 via fixing components such as bolts (not shown), the lower surface of the second clamp ring 23 can be flush with or lower than the lower surface of the peripheral portion 122 of the coupling plate 12 and the upper surface of the third clamp ring 18 is configured to be flush with or higher than the top surface of the supporting plate 13. Furthermore, the thickness of the third clamp ring 18 along the vertical direction is greater than the depth of the fourth step hole 131D of the step hole 131, the thickness of the second clamp ring 23 along the vertical direction is greater than the depth of the edge recess 231 of the peripheral portion 122 of the coupling plate 12, and the height difference h1 between the thickness of the third clamp ring 18 and the depth of the fourth step hole 131D should be greater than the height difference h2 between the thickness of the second clamp ring 23 and the depth of the edge recess 231, so that when the coupling plate 12 moves downward to the lowermost position relative to the balance frame 11, the third clamp ring 18 can block the coupling plate 12 from continuing to move downward by supporting the lower surface of the peripheral portion 122 of the coupling plate 12, so as to provide a limiting function.

[0037] The function of the flexible membrane 14 is to cooperate with other parts of the carrier head 1 to form at least two gas chambers with adjustable pressure, so as to further fine-tune the pressure profile applied to the substrate to improve the uniformity and consistency of chemical mechanical polishing. Figure 5 As shown, the flexible membrane 14 is formed to be composed of a circular bottom plate portion 141, an annular edge wrinkle wall 142 and at least one annular inner wrinkle wall 143. The edge wrinkle wall 142 vertically extends upward along the circumferential edge of the circular bottom plate portion 141 and horizontally extends a distance toward the radial inner side at its top end to form an annular first horizontal extension portion 144, and the first horizontal extension portion 144 has an annular first sealing protrusion 145 at its inner edge; similarly, the annular inner wrinkle wall 143 is arranged concentrically and parallel to the edge wrinkle wall 142 and is located radially inward thereof, and the inner wrinkle wall 143 is arranged concentrically and parallelly to the edge wrinkle wall 142 and is located radially inward thereof. 43 extends vertically upward from the upper surface of the circular bottom plate portion 141 and horizontally extends a distance radially outward at its top end to form an annular second horizontal extension portion 146, and the second horizontal extension portion 146 has an annular second sealing protrusion 147 at its outer edge; or, the inner wrinkled wall 143 extends vertically upward from the upper surface of the circular bottom plate portion 141 and horizontally extends a distance radially inward at its top end to form an annular second horizontal extension portion 146, and the second horizontal extension portion 146 has an annular second sealing protrusion 147 at its outer edge.

[0038] As an embodiment of the present invention, the annular pressure plate 15 on the carrier head 1 can be assembled from multiple parts or can be an integrally formed part; at least one of the innermost wrinkled wall 143 of the elastic membrane 14 and the edge wrinkled wall 142 is clamped and fixed to the lower surface of the carrier plate 13 by the annular pressure plate 15, so as to form independent chambers between the elastic membrane 14 and the carrier plate 13, and the pressure of each chamber is adjusted by passing gas in or out.

[0039] like Figure 1 and Figure 5 As shown, the first sealing protrusion 145 and a portion of the adjacent first horizontal extension portion 144 are clamped and fixed to the lower surface of the supporting plate 13 by the upper outer edge of the annular pressure plate 15 via bolts (not shown), and the second sealing protrusion 147 and a portion of the adjacent second horizontal extension portion 146 are clamped and fixed to the lower inner edge of the bottom of the step hole 131 of the supporting plate 13 by the upper inner edge of the annular pressure plate 15, thereby forming a relatively sealed and pressure-adjustable second pressure chamber 24A and an annular third pressure chamber 24B, respectively. Gas can be introduced into or extracted from the second pressure chamber 24A through the first through hole 115 to adjust the pressure of the chamber. Similarly, gas can be introduced into or extracted from the third pressure chamber 24B through other through holes or fluid channels not shown to adjust the pressure of the chamber, thereby precisely adjusting the pressure profile applied to the substrate in partitions to achieve more uniform and consistent polishing.

[0040] It can be seen from the above description that 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. In order to monitor the polishing process in real time, especially to monitor the real-time thickness of the functional film layer on the surface of the substrate during the polishing process and determine the polishing end point, it is also necessary to measure the thickness of the polished substrate through a series of devices such as eddy current sensors and / or optical sensors, that is, to monitor the real-time thickness of the functional film layer on the substrate.

[0041] Although the present embodiment shows a solution of a flexible membrane 14 with two independent pressure chambers, in order to further optimize the uniformity and consistency of chemical mechanical polishing, more adjustable pressure chambers can be formed by setting more inner wrinkled walls 143 with sealing structures and / or horizontal extensions. Accordingly, the annular pressure plate 15 can be formed by a combination of multiple different annular pressure plate components. Exemplarily, the annular pressure plate 15 can be formed as an assembly. The annular pressure plate assembly 15 not shown can include 2, 3, 4, 5, 6 or 7 annular pressure plate components, which clamp part or all of the sealing parts of the inner walls of different adjustable pressure chambers to the carrier plate 13 respectively; in other words, the number, structure, composition and / or matching form of the annular pressure plate 15 and the inner wrinkled wall 143 in the present embodiment should not be understood as limiting, but should be understood in a broader sense with reference to the prior art. The present embodiment omits the description of the prior art only to highlight its core invention.

[0042] like Figure 6 As shown, when the carrier head 1 presses the substrate 201 against the rotating polishing pad (not shown) for polishing, it is necessary to use the eddy current film thickness measuring device 203 installed on the polishing disk to measure the thickness of the metal film layer 202 on the surface of the substrate 201 to determine the polishing end point. Since metal materials have a reflective effect on the electromagnetic waves emitted by the eddy current film thickness measuring device 203 and non-metallic materials generally transmit electromagnetic waves, and within a certain range, the reflection intensity of the electromagnetic waves is generally positively correlated with the thickness of the metal film layer. Therefore, the eddy current film thickness measuring device 203 can be used to emit electromagnetic waves in the direction of the metal film layer 202 on the substrate 201 and measure the intensity of the electromagnetic waves reflected by the metal film layer 202 to measure the thickness of the film layer. The balance frame 11 is usually made of metal materials with higher strength, such as stainless steel, to meet the strength requirements. However, when the chassis 112 of the balance frame 11 is made of metal material, it is closer to the eddy current film thickness measuring device 203 than the flange 114, so it will reflect the electromagnetic waves emitted by the eddy current film thickness measuring device 203 to a greater extent, which will have an impact on the thickness measurement accuracy of the metal film layer 202 that is difficult to ignore, thereby affecting the accuracy of the detection of the polishing end point.

[0043] For this reason, it is preferred to use materials with relatively low relative magnetic permeability and / or electrical conductivity (closer to 1), such as 304 grade austenitic stainless steel, aluminum-magnesium alloy and / or titanium alloy, to manufacture the balance frame 11. Since the relative magnetic permeability of such materials is less than 1.01, the reflection effect on electromagnetic waves is very weak, so the influence on the measurement accuracy of the film thickness is acceptable. It should be understood that the structural dimensions and proportional relationships in the drawings in this embodiment or implementation mode, especially Figure 6 The sizes of the middle substrate 201 , the metal film layer 202 and the eddy current film thickness measuring device 203 do not represent their actual sizes, nor do they represent the proportional relationship between their sizes, but are merely shown to reflect their functions.

[0044] Although metal materials with relatively low magnetic permeability can reduce the impact of the chassis 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 less than 1000nm and the error requirement for measurement accuracy is generally less than 10nm, it is necessary to further reduce the impact of the material of the balance frame 11 on the film thickness measurement accuracy in some cases, that is, it is necessary to further reduce the reflection of electromagnetic waves by the chassis 112 of the balance frame 11.

[0045] Preferably, Figure 7 As shown, a wave-breaking layer 204 can be provided on the lower surface of the chassis 112 of the balance frame 11. The thickness of the wave-breaking layer 204 is generally 0.03 mm to 2 mm, and the wave-breaking layer 204 is generally formed of at least one of permalloy, ferrite, barium titanate, silicon carbide, graphite, metal powder, conductive fiber and / or chiral material. It is easy to understand that the wave-breaking layer 204 can be combined with the entire lower surface of the chassis 112 by a variety of different methods such as pasting a wave-breaking patch, brushing an adhesive containing a wave-breaking powder material, vapor deposition of a wave-breaking material, electroplating, spraying, pasting or coating a wave-breaking material, and preferably, the radius of the wave-breaking layer 204 is greater than the radius of the chassis 112 to cover the bottom area of ​​the outer surface of the peripheral wall 113 adjacent to the edge of the chassis 112, thereby further reducing the potential impact of the balance frame 11 on the film thickness measurement; it is easy to understand that the wave-breaking layer 204 does not cover the first through hole 115.

[0046] In the above-mentioned specific embodiments, the balance frame 11 is usually made of metal material as a whole to meet the strength requirements and processing accuracy requirements, but in order to further reduce the influence of the chassis of the balance frame on the film thickness measurement, it can also be formed as Figure 8The scheme shown in the figure, 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, the chassis portion 312, the peripheral wall portion 313, and the flange portion 314 are integrally processed from the same non-metallic material, and the middle shaft sleeve 311B is made of the same metal material and has a connecting hole for combining with the middle shaft core 311A ​​at the lower part of the inner part thereof, and the size of the connecting hole matches the size of the middle shaft core 311A ​​so that the middle shaft core 311A ​​can be completely coaxially inserted and fixed in the connecting hole and at the same time ensure that the inner part of the connecting hole The surface is airtightly combined with the outer surface of the center axis core 311A; the center axis core 311A ​​has a center axis through hole 315A extending through along its axis, and the center axis sleeve 311B has a center axis sleeve through hole 315B extending through along its axis. When the center axis sleeve 311B is combined with the center axis core 311A, the center axis core through hole 315A and the center axis sleeve through hole 315B with the same radius are aligned with each other to form a balance frame through hole 315 extending through along the rotation axis of the balance frame 31. Here, the function of the through hole 315 of the balance frame 31 is the same as the function and effect of the first through hole 115.

[0047] like Figure 8 As shown, considering the processing technology and strength requirements, the length-to-diameter ratio of the central axis core is 2 to 6. Preferably, the length-to-diameter ratio of the central axis core is 3 to 5. However, in some application scenarios, the central axis core 311A ​​may also extend vertically upward to the upper surface of the central axis sleeve 311B, that is, the height of the central axis core 311A ​​(excluding the chassis portion) is equivalent to the height of the central axis sleeve 311B; and considering the reflection and strength requirements of electromagnetic waves, the thickness of the hole wall of the connecting hole at the lower part of the central axis sleeve 311B should not exceed 50% of the thickness of the upper part of the central axis sleeve 311B. Preferably, in order to ensure the shape and position tolerances between different parts of the balance frame 31, the balance frame through hole 315 composed of the center axis core through hole 315A and the center axis sleeve through hole 315B is formed by machining after the center axis core 311A ​​and the center axis sleeve 311B are fixed together, and at least one of the chassis part 312, the peripheral wall part 313, and the flange part 314 is formed by machining after the center axis core 311A ​​and the center axis sleeve 311B are fixed together.

[0048] The material forming the central axis core 311A ​​and other parts is at least one of PPS plastic, PEEK plastic, PET plastic, POM plastic, ceramic material or semiconductor material, and preferably, reinforcing materials such as glass fiber, carbon fiber and / or ceramic are added thereto, or composite plastics with better strength are directly used to manufacture these parts, or the central axis core 311A ​​can also be manufactured using materials such as titanium or titanium alloys; the central axis sleeve 311B is preferably made of metal materials with relatively low magnetic permeability such as austenitic stainless steel with grade 304, aluminum-magnesium alloy, titanium alloy, etc. It should be understood that the diameter of the central axis core 311A ​​near the chassis portion 312 can be larger than the diameter of other parts to enhance the strength of the junction between the central axis core 311A ​​and the chassis portion 312, and the junction between the central axis core 311A ​​and the chassis portion 312 preferably adopts an arc-shaped fillet transition to optimize the strength of this part; and in order to further reduce the influence of the metal central axis sleeve 311B on the measurement accuracy of the eddy current film thickness measuring device 203, a layer of absorbing material can be coated on its surface, or a layer of absorbing material can be coated on the area of ​​the sleeve 311B that contacts the root of the central axis core 311A ​​to reduce the influence of the central axis sleeve 311B, especially the root of the central axis sleeve 311B, on the eddy current detection signal.

[0049] In fact, the influence of metal materials on eddy current signals also includes the possibility that electromagnetic waves may form induced eddy currents in metal materials, resulting in a portion of the electromagnetic waves received by the eddy current film thickness measurement device 203 possibly coming from the electromagnetic waves generated by the induced eddy currents. This is also one of the advantages of the present invention of introducing metal materials, wave-absorbing materials, and non-metallic materials with relatively low magnetic permeability into the construction of the components of the carrier head 1.

[0050] In addition, if Figure 2 and Figure 8 As shown, the difference between the balance frame 31 and the balance frame 11 is that the entire or a part of the chassis portion 312 of the balance frame 31 is formed as a downward protrusion, and the downward protrusion extends downward in the vertical direction to no lower than the lower surface of the annular pressure plate 15; the role of such a downward protrusion is to prevent the central part of the substrate from being over-lifted due to excessive deformation of the second pressure chamber 24A during the loading process of the substrate, that is, when the middle area of ​​the substrate is over-lifted, it will be blocked by the downward protrusion, thereby preventing the lower inner edge of the annular pressure plate 15 from being excessively deformed and / or the characteristic structure of the substrate from being damaged due to excessive lifting; and the role of making the downward protrusion extend downward in the vertical direction to no lower than the lower surface of the annular pressure plate 15 is to prevent the protrusion from being too close to the substrate so that in the process of lifting the substrate, the protrusion acts on the substrate before the annular pressure plate 15, resulting in excessive force in the middle area of ​​the substrate, thereby preventing the chassis portion 312 from being excessively deformed or damaged in the middle of the substrate due to excessive lifting.

[0051] Fig. 9 1 is a schematic diagram of the structure of another embodiment of the balance frame 11 according to the present invention. The central area of ​​the bottom plate 112 of the balance frame 11 has a downward convex structure 117 extending downward in the vertical direction. The first through hole 115 provided along the axis of the middle axis 111 and extending from the upper surface of the middle axis 111 to the lower surface of the downward convex structure 117 extends downward in the vertical direction to a point not lower than the lower surface of the annular pressure plate 15. The purpose of providing the downward convex structure 117 is to prevent the central part of the substrate from being over-lifted due to excessive deformation of the second pressure chamber 24A during the loading of the substrate, that is, when the central area of ​​the substrate is When the domain is excessively pulled, it will be blocked by the convex structure 117, thereby preventing the lower inner edge of the annular pressure plate 15 from being excessively deformed and / or causing damage to the characteristic structure of the substrate due to excessive pulling; and the convex structure 117 is configured to extend downward in the vertical direction to not lower than the lower surface of the annular pressure plate 15, so as to prevent the convex structure 117 from being too close to the substrate, so that in the process of pulling the substrate, the convex structure 117 acts on the substrate before the annular pressure plate 15, resulting in excessive force in the middle area of ​​the substrate, thereby preventing the convex structure 117 from being excessively deformed or damaged in the middle of the substrate due to excessive pulling.

[0052] In some embodiments, the downward protruding structure 117 is formed integrally with the balance frame 11 .

[0053] As one aspect of this embodiment, the lower convex structure 117 is a frustum structure, which includes an upper frustum and a lower frustum, and the size of the lower frustum is larger than that of the upper frustum; the lower portion of the balance frame 11 is provided with a conical hole for fitting and fixing the upper frustum, and the inner wall of the conical hole is not less than 3 mm from the intersection of the middle axis portion 111 and the inner bottom surface of the chassis portion 112 to ensure the strength of the balance frame 11.

[0054] As one aspect of this embodiment, the cross-sectional radius of the lower cone gradually increases from bottom to top, that is, the cross-sectional radius corresponding to the contact between the lower cone and the chassis portion 112 is the largest, and its cross-sectional radius is 5-10mm. The angle between the generatrix of the lower cone and the central axis is 10-30°. Preferably, the angle between the generatrix of the lower cone and the central axis is 20°.

[0055] As another aspect of this embodiment, the convex structure 117 arranged in the central area of ​​the lower surface of the balance frame 11 is made of non-metallic material. The area where the convex structure 117 is located can transmit the electromagnetic waves reflected by the metal film layer 202, thereby weakening the influence of the central area of ​​the balance frame 11 on the film thickness measurement accuracy, thereby improving the accuracy of detecting the polishing end point.

[0056] exist Fig. 9In the illustrated embodiment, the downward convex structure 117 is fixedly coupled to the bottom of the balancing frame 11 by adhesive. Specifically, the upper frustum of the downward convex structure 117 is fixed in the conical hole at the bottom of the balancing frame 11 by adhesive. The downward convex structure 117 is made of non-metallic material, and the area where the downward convex structure 117 is located can transmit the electromagnetic waves reflected by the metal film layer 202, so as to weaken the influence of the central area of ​​the balancing frame 11 on the accuracy of film thickness measurement, thereby improving the accuracy of detection of the polishing end point.

[0057] Fig.10 yes Fig. 9 The schematic diagram of the installation of the balance frame 11 in the carrier head 1 is shown, and a wave-breaking layer 204 is provided on the lower surface of the chassis portion 112 of the balance frame 11. At the same time, a downwardly extending lower convex structure 117 is provided in the central area of ​​the chassis portion 112 of the balance frame 11. The lower convex structure 117 is fixed in the conical hole at the lower part of the balance frame 11 by an adhesive. The adhesive may also contain wave-breaking materials, such as ferrite, barium titanate, silicon carbide, graphite, metal powder, conductive fiber, chiral material, etc., to weaken the influence of the adhesive on the film thickness measurement.

[0058] The accompanying drawings of this specification are schematic diagrams, which assist in explaining the concept of the present invention and schematically represent the shapes of the various parts and their mutual relationships. It should be understood that in order to facilitate the clear representation of the structure of the various components of the embodiments of the present invention, the various drawings are not drawn according to the same scale, and the same reference numerals are used to represent the same parts in the drawings. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0059] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A carrier head for chemical mechanical polishing, comprising a coupling plate, a balancing frame, a carrier plate, and a flexible membrane, wherein the balancing frame has a central axis portion and a chassis portion formed at the bottom end of the central axis portion, wherein the central axis portion is slidably disposed in a central through hole of the coupling plate and the chassis portion is connected to the carrier plate to drive the carrier plate to move up and down relative to the coupling plate, wherein a portion of the flexible membrane is clamped to the lower portion of the carrier plate to form a sealed chamber, wherein a wave-breaking layer is disposed on the lower surface of the chassis portion, and a radius of the wave-breaking layer is greater than a radius of the chassis portion; wherein a central area of ​​the chassis portion of the balancing frame has a downwardly extending downwardly convex structure, wherein the downwardly convex structure is a truncated cone formed of a non-metallic material, and wherein the truncated cone is fixedly bonded to the bottom of the balancing frame by an adhesive; wherein the adhesive contains a wave-breaking material to weaken the influence of the adhesive on the film thickness measurement.

2. The carrier head according to claim 1, wherein: The carrier head has an annular pressure plate, the flexible membrane has an annular edge wrinkle extending upward along its bottom surface and at least one annular inner wrinkle wall arranged concentrically with the edge wrinkle wall, and at least one of the innermost inner wrinkle wall and the edge wrinkle wall is clamped and fixed to the lower surface of the carrier plate by the annular pressure plate.

3. The carrier head according to claim 1, wherein: The wave-breaking layer is formed of at least one of permalloy, ferrite, barium titanate, silicon carbide, graphite, metal powder, conductive fiber and / or chiral material.

4. The carrier head according to claim 1, wherein: The wave-breaking layer is fixed to the lower surface of the chassis by electroplating, spraying, pasting, coating or vapor deposition.

5. The carrier head according to claim 1, wherein: The material of the balance frame is a metal material whose relative magnetic permeability does not exceed 304 austenitic stainless steel.

6. The carrier head according to claim 2, wherein: The downward convex structure extends downward in the vertical direction to a level not lower than the lower surface of the annular pressure plate.

7. The carrier head according to any one of claims 1 to 6, characterized in that: The thickness of the wave-breaking layer is 0.03 mm to 2 mm.

8. A chemical mechanical polishing device, characterized in that: The chemical mechanical polishing apparatus comprises the carrier head as claimed in any one of claims 1 to 7.

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