Elastic film and bearing head for electrochemical mechanical polishing

Abstract

The utility model discloses an elastic film and a bearing head for electrochemical mechanical polishing, and belongs to the technical field of wafer manufacturing. The elastic film includes: a disc-shaped bottom plate portion; the upright part vertically extends upwards along the edge of the bottom plate part; the upright part is provided with at least one horizontal rib; the separation ribs extend upwards along the bottom plate part and are positioned on the inner side of the upright part so as to separate the elastic film into a plurality of cavities; a mounting hole is formed in the center of the bottom plate part, a fixing rib is arranged on the inner edge of the mounting hole so as to be connected with an electric connection assembly of an electrochemical polishing bearing head, and the electric connection assembly is arranged between the elastic film and an electrode of a power supply.

Description

An elastic membrane and bearing head for electrochemical mechanical polishing Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and more particularly to an elastic film and a support head for electrochemical mechanical polishing. Background Technology

[0002] The integrated circuit industry is the core of the information technology industry, playing a crucial role in promoting the digital and intelligent transformation and upgrading of the manufacturing industry. Chips are the carriers of integrated circuits, and chip manufacturing involves processes such as integrated circuit design, wafer fabrication, wafer processing, electrical measurement, dicing, packaging, and testing. Among these, electrochemical mechanical polishing (ECMP) is one of the processes in wafer fabrication.

[0003] As semiconductor process nodes advance to the nanometer scale (e.g., below 5nm and 3nm), traditional CMP faces numerous bottlenecks, while ECMP, with its unique synergistic mechanism, serves as a key technological complement. For example, when polishing high-hardness SiC, traditional CMP is extremely inefficient, while ECMP generates an oxide layer in the electrolyte and mechanically removes the softened layer, effectively improving the material removal rate.

[0004] The electrochemical mechanical carrier head is an important component of the ECMP system, responsible for loading the wafer and placing it in the electrolyte; however, existing electrochemical mechanical carrier heads also have some problems:

[0005] 1) The connection between the elastic diaphragm of the bearing head and the electrodes of the power supply is not reliable enough, which will affect the stability of the bearing head operation;

[0006] 2) Insufficient conductivity uniformity of the elastic film results in differences in the interaction between the electrolyte and different areas of the wafer, which in turn affects the material removal rate on the wafer surface. Summary of the Invention

[0007] In view of this, embodiments of this application provide an elastic membrane and a bearing head for electrochemical mechanical polishing, to at least partially solve the above-mentioned problems.

[0008] According to a first aspect of the embodiments of this application, an elastic film for electrochemical mechanical polishing is provided, comprising:

[0009] The base plate is disc-shaped.

[0010] An upright portion extends vertically upward along the edge of the base plate portion; the upright portion is provided with at least one horizontal rib.

[0011] Dividing ribs extend upward along the bottom plate and are located inside the upright portion to divide the elastic membrane into multiple chambers;

[0012] The base plate has a mounting hole at its center and a fixing rib along its inner edge to connect the electrical connection assembly of the electrochemical polishing bearing head. The electrical connection assembly is located between the elastic membrane and the electrode of the power source.

[0013] In some embodiments, the fixing rib is a ring structure that extends horizontally toward the center of the base plate, and the length of the fixing rib is less than or equal to 1 / 2 of the inner diameter of the mounting hole.

[0014] In some embodiments, the wall thickness of the fixing rib is 1 / 4 to 1 / 2 of the thickness of the base plate, and an annular protrusion is provided at the end of the rib facing the center of the elastic membrane, the annular protrusion extending vertically along the end of the fixing rib.

[0015] In some embodiments, the base plate, the upright portion, and the partition ribs are made of silicone rubber or neoprene rubber, and the base plate contains more than or equal to 50% silver powder.

[0016] In some embodiments, the bottom surface of the base plate is provided with an annular groove, and a matching annular conductive sheet is bonded to the inside of the annular groove.

[0017] In some embodiments, the annular groove is disposed at the partition rib of an adjacent chamber, and its depth is 0.2 to 0.5 mm.

[0018] In some embodiments, conductive blocks are pre-embedded on the bottom surface of the base plate. The conductive blocks are circular, rectangular, triangular, and / or elliptical, and are evenly distributed.

[0019] In some embodiments, the conductive block is disposed at the partition rib of an adjacent chamber.

[0020] In some embodiments, the partition bar includes a vertical segment and a horizontal segment, both integrally formed; the horizontal segment is located above the fixing bar.

[0021] According to a second aspect of the embodiments of this application, a carrier head for electrochemical polishing includes:

[0022] The coupling disc has a positioning hole in the center;

[0023] The carrier plate is fitted with a shaft, which is slidably connected to a positioning hole, so that the carrier plate rotates with the coupling plate and / or moves in the vertical direction;

[0024] The elastic membrane described above is disposed below the carrier disk and is used to load the wafer to be processed;

[0025] A retaining ring is positioned below the support plate and on the outer periphery of the elastic membrane;

[0026] An electrical connection assembly is vertically disposed in a mounting hole arranged along the axis, with one end connected to a power source and the other end connected to the central cavity of the elastic membrane, so that the wafer to be processed is in an electric field formed between the elastic membrane and the polishing fluid.

[0027] In some embodiments, at least a portion of the electrical connection assembly is a flexible element that extends and retracts vertically to accommodate the deformation of the elastic membrane, thereby creating a stable electric field between the elastic membrane and the polishing fluid.

[0028] In some embodiments, the electrical connection assembly includes an upper conductive rod and a lower conductive rod, which are detachably connected by a spring-loaded pin structure to adjust the length of the electrical connection assembly; the spring-loaded pin structure includes a spring and a pin shaft, which are engaged together and abut against grooves on the opposite surfaces of the upper and lower conductive rods.

[0029] In some embodiments, a conductive disk is disposed below the lower conductive rod, which includes a conductive rod and a disk base integrally formed; the conductive rod is connected to the lower conductive rod, the conductive rod passes through the mounting hole, and the top surface of the disk base is bonded to the fixing rib of the elastic membrane by conductive adhesive.

[0030] The beneficial effects of this utility model include:

[0031] a. The provided elastic membrane is equipped with mounting holes for fixing electrical connection components. The inner edge of the mounting holes is provided with fixing ribs to connect with the snap-fit ​​groove of the second protective sleeve through the annular protrusion, which effectively ensures the reliability of fixing the electrical connection components and the elastic membrane.

[0032] b. The length of the fixing rib is less than or equal to 1 / 2 of the inner diameter of the mounting hole, so that the fixing rib has a certain degree of flexibility, so as to adjust the load of the electrical connection assembly on the polishing pad when the central chamber 39 expands and compresses.

[0033] c. In some embodiments, the wall thickness of the fixing rib is 1 / 4 to 1 / 2 of the thickness of the base plate to maintain the flexibility of the fixing rib.

[0034] d. The elastic membrane is made of silicone rubber or neoprene rubber and contains more than or equal to 50% silver powder to ensure the conductivity of the elastic membrane;

[0035] e. The Shore hardness of the elastic film is 55 to 65, which gives the elastic film a certain degree of flexibility, so that the elastic film can load the wafer by adsorption.

[0036] f. The surface of the base plate of the elastic membrane is provided with multiple annular grooves, and the surface of the base plate is also provided with rectangular grooves connecting adjacent annular grooves; the annular conductive sheet and the rectangular conductive sheet are metal sheets, which are bonded to the bottom surface of the elastic membrane with conductive adhesive in order to improve the uniformity of conductivity of the elastic membrane without affecting the flexibility of the elastic membrane itself.

[0037] g. The annular groove is set at the partition rib of the adjacent chambers of the elastic membrane. This weakens the stress concentration of the elastic membrane at the partition rib to a certain extent, suppresses the pressure coupling between adjacent chambers, and ensures the accuracy of the polishing pressure applied to each chamber of the elastic membrane.

[0038] h. The radial width of the annular groove is at least 2 to 3 times the wall thickness of the partition rib, and its depth is 0.2 to 0.5 mm, in order to reduce stress concentration at the partition rib.

[0039] i. Multiple conductive blocks are pre-embedded on the bottom surface of the elastic membrane to improve the conductivity uniformity of the elastic membrane; the conductive blocks are circular, rectangular, triangular and / or elliptical, and are set at the partition ribs of adjacent chambers to weaken the stress concentration of the elastic membrane at the partition ribs, suppress the pressure coupling between adjacent chambers, and ensure the accuracy of the polishing pressure applied to each chamber of the elastic membrane. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0041] Figure 1 is a schematic diagram of an elastic membrane for electrochemical mechanical polishing provided in an embodiment of the present invention;

[0042] Figure 2 is a magnified view of part A in Figure 1;

[0043] Figure 3 is a bottom view of an elastic membrane provided in an embodiment of the present invention;

[0044] Figure 4 is a bottom view of the elastic membrane provided in another embodiment of the present invention;

[0045] Figure 5 is a partial enlarged view of the base plate provided in an embodiment of the present invention;

[0046] Figure 6 is a schematic diagram of a support head for electrochemical mechanical polishing provided in one embodiment of the present invention;

[0047] Figure 7 is a magnified view of part B in Figure 6;

[0048] Figure 8 is a schematic diagram of a conduction disk provided in an embodiment of the present invention;

[0049] Figure 9 is a schematic diagram of the first protective sleeve provided in an embodiment of the present invention;

[0050] Figure 10 is a schematic diagram of the second protective sleeve provided in an embodiment of the present invention;

[0051] Figure 11 is a schematic diagram of an electrochemical mechanical polishing system provided in an embodiment of the present invention. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0053] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0054] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0055] Figure 1 is a schematic diagram of an elastic membrane 30 for electrochemical mechanical polishing according to an embodiment of the present invention. The elastic membrane 30 includes:

[0056] The base plate 31 is a disk-shaped structure, and its bottom is used to hold the wafer to be polished;

[0057] The upright portion 32 extends vertically upward along the edge of the base plate portion 31; wherein the upright portion 32 is provided with at least one horizontal rib 33 to define the lateral position of the elastic membrane 30.

[0058] The dividing rib 34 extends upward along the bottom plate portion 31 and is located inside the upright portion 32 to divide the elastic membrane 30 into multiple chambers.

[0059] In the embodiment shown in Figure 1, there are three dividing ribs 34, which, together with the upright portion 32, roughly divide the elastic membrane 30 into four independent chambers; the top of the upright portion 32 is provided with two horizontal ribs 33, and an independent chamber is also formed between adjacent horizontal ribs 33.

[0060] In this invention, the base plate 31 has a mounting hole 311 at its center for fixing the electrical connection assembly 50 (shown in FIG. 6) of the carrier head 100 for electrochemical polishing. The electrical connection assembly 50 is disposed between the elastic membrane 30 and the electrode of the power supply 200. That is, the electrical connection assembly 50 is disposed in the central cavity 39 of the elastic membrane 30, and the partition rib 34 located in the central region, together with the base plate 31 and the carrier plate 20 of the carrier head 100, forms the central cavity 39.

[0061] Figure 2 is a partial enlarged view of point A in Figure 1. The inner edge of the mounting hole 311 is provided with a fixing rib 35. The fixing rib 35 is a ring structure that extends horizontally toward the center of the base plate 31.

[0062] Furthermore, the length of the fixing rib 35 is less than or equal to 1 / 2 of the inner diameter R of the mounting hole 311, so that the fixing rib 35 has a certain degree of flexibility, so as to adjust the load of the electrical connection assembly 50 on the polishing pad when the central cavity 39 expands and compresses.

[0063] In some embodiments, the wall thickness of the fixing rib 35 is 1 / 4 to 1 / 2 of the thickness of the base plate portion 31 to maintain the flexibility of the fixing rib 35. An annular protrusion 351 is disposed at the end of the fixing rib 35 facing the center of the elastic membrane 30, wherein the annular protrusion 351 extends vertically along the end of the fixing rib 35.

[0064] In this invention, the base plate 31, upright portion 32, and separating ribs 34 of the elastic film 30 are made of silicone rubber or neoprene rubber to balance the flexibility and strength of the elastic film 30. The base plate 31 contains greater than or equal to 50% silver powder to ensure the conductivity of the portion of the elastic film 30 in contact with the wafer. Specifically, during the molding of the elastic film 30, silver powder is uniformly mixed into liquid rubber to form the base plate 31; then, undoped liquid rubber is poured in to form the upright portion 32 and separating ribs 34, etc.

[0065] Furthermore, the elastic film 30 has a Shore hardness of 55 to 65, which gives the elastic film 30 a certain degree of flexibility so that the elastic film 30 can load the wafer by adsorption.

[0066] Figure 3 is a bottom view of an elastic membrane 30 provided in an embodiment of the present invention. The bottom surface of the elastic membrane 30 is provided with an annular groove 36, that is, the lower surface of the bottom plate portion 31 is provided with an annular groove 36.

[0067] Furthermore, there are multiple annular grooves 36, which are concentrically arranged on the bottom surface of the elastic membrane 30. The surface of the bottom plate portion 31 is also provided with rectangular grooves 37 to connect adjacent annular grooves 36.

[0068] Furthermore, a matching annular conductive sheet is bonded inside the annular groove 36, and a matching rectangular conductive sheet is bonded inside the rectangular groove 37, in order to further improve the conductivity uniformity of the bottom plate portion 31 of the elastic membrane 30.

[0069] It should be noted that the annular and rectangular conductive sheets are thin metal sheets, which are bonded to the bottom surface of the elastic membrane 30 using conductive adhesive, so as to improve the uniformity of conductivity of the bottom plate 31 without affecting the flexibility of the bottom plate 31 itself.

[0070] In this invention, the depth of the annular groove 36 and the rectangular groove 37 is 0.2 to 1.5 mm; preferably, the depth of the annular groove 36 and the rectangular groove 37 is 0.2 to 0.5 mm.

[0071] In some embodiments, the annular groove 36 is disposed at the partition rib 34 of the adjacent chambers of the elastic membrane 30, which to some extent weakens the stress concentration of the elastic membrane 30 at the partition rib 34, suppresses the pressure coupling between adjacent chambers, and ensures the accuracy of the polishing pressure applied to each chamber of the elastic membrane 30.

[0072] Specifically, the radial width of the annular groove 36 is at least 2 to 3 times the wall thickness of the partition rib 34, and its depth is 0.2 to 0.5 mm, in order to reduce stress concentration at the partition rib.

[0073] Figure 4 is a bottom view of the elastic membrane 30 provided in another embodiment of the present invention. In this embodiment, a plurality of circular conductive blocks 38 are pre-embedded in the bottom plate portion 31 of the elastic membrane 30. The conductive blocks 38 are metal sheets to improve the conductivity uniformity of the bottom plate portion 31. That is, the bottom surface of the bottom plate portion 31 is provided with a groove for bonding the conductive blocks 38, and conductive adhesive is used to bond the conductive blocks 38 to the groove on the bottom surface of the bottom plate portion 31.

[0074] It is understandable that the conductive blocks 38 can also be rectangular, triangular and / or elliptical, and are evenly distributed.

[0075] In some embodiments, the conductive block 38 is disposed at the partition rib 34 of adjacent chambers to weaken the stress concentration of the elastic membrane 30 at the partition rib 34, suppress the pressure coupling between adjacent chambers, and ensure the accuracy of the polishing pressure applied to each chamber of the elastic membrane 30.

[0076] In some embodiments, the conductive block 38 may also be disposed on the inner side of the bottom plate portion 31 of the elastic film 30, as shown in FIG5. With this arrangement, the groove for placing the conductive block 38 is disposed on the inner side of the elastic film 30 to prevent particles in the polishing fluid from accumulating on the outer edge of the conductive block 38 and forming crystals. These crystals falling off can cause wafer scratches.

[0077] In the embodiment shown in Figure 2, the partition rib 34 includes a vertical section 341 and a horizontal section 342, which are integrally formed; wherein, the horizontal section 342 is located above the fixing rib 35. That is, the fixing rib 35 and the horizontal section 342 of the partition rib 34 have a certain distance between them to facilitate the installation and fixation of the electrical connection assembly 50.

[0078] Figure 6 is a schematic diagram of a support head 100 for electrochemical mechanical polishing according to an embodiment of the present invention, and Figure 7 is a partial enlarged view of point B in Figure 6. The support head 100 includes:

[0079] The coupling disc 10 has a disc-shaped structure. A connecting flange is provided on the top of the coupling disc 10 to connect to the output shaft of the drive motor, thereby driving the coupling disc 10 and its connected components to rotate around the axis. A vertical positioning hole 11 is provided in the center of the coupling disc 10.

[0080] The bearing plate 20 has a shaft portion 21 on its upper part, which is matched with the positioning hole 11 of the coupling plate 10. That is, the shape and size of the shaft portion 21 match the shape and size of the positioning hole 11, and the shaft portion 21 is slidably connected inside the positioning hole 11. At the same time, the coupling plate 10 is connected to the bearing plate 20 through an annular diaphragm 60, so that the bearing plate 20 can rotate with the coupling plate 10 and / or move in the vertical direction. The shaft portion 21 has a through electrical connection component mounting hole 211 inside, which extends along the length direction of the shaft portion 21.

[0081] The elastic membrane 30 shown in Figure 1 is disposed below the carrier disk 20 and is used to load the wafer to be processed. The elastic membrane 30 is fixed below the carrier disk 20 by the loading assembly 80, which includes a loading disk and a loading ring. The horizontal ribs 33, the partition ribs 34, etc. are fixed below the carrier disk 20 by a snap-fit ​​method.

[0082] A retaining ring 40 is positioned below the carrier disk 20 and on the outer periphery of the elastic membrane 30 to prevent the wafer to be polished from sliding out of the inside of the carrier head 100.

[0083] Electrical connection component 50 is vertically disposed inside electrical connection component mounting hole 211;

[0084] Furthermore, one end of the electrical connection component 50 is connected to the power supply 200 (shown in Figure 11), and the other end of the electrical connection component 50 is connected to the base plate portion 31 of the elastic film 30, so that the wafer to be processed is in the electric field formed between the elastic film 30 and the polishing slurry. Typically, the positive terminal of the power supply 200 is connected to the wafer through the electrical connection component 50, so that the wafer enters the polishing slurry as the anode; after the wafer is energized, an oxidation reaction occurs, and the metal ions on its surface are ionized and dissolved to achieve material removal.

[0085] While electrochemical action occurs, the abrasive particles in the polishing slurry physically grind the wafer surface to remove the passivation film or softening layer generated by the electrochemical reaction, exposing a fresh surface for continuous dissolution.

[0086] The bearing head 100 also includes a pneumatic control assembly 70, as shown in Figure 6, which communicates with the central chamber 39 and the annular chamber of the elastic membrane 30 to control the polishing load applied to each chamber of the elastic membrane 30. The pneumatic control assembly 70 typically includes functional devices such as a proportional valve, a flow meter, a pressure sensor, and a controller. For details on the connection relationships of the various functional devices, please refer to patent CN110977750A, which will not be elaborated here.

[0087] To address the issues of wire pulling and tearing present in existing bearing heads 100, the electrical connection component 50 provided by this invention is at least partially a flexible component that can extend and retract vertically to accommodate the deformation of the elastic membrane 30, thereby forming a stable electric field between the elastic membrane 30 and the polishing fluid to ensure the reliable operation of the bearing head 100.

[0088] In Figure 7, the electrical connection component 50 is disposed in the electrical connection component mounting hole 211 of the shaft portion 21. The bottom of the electrical connection component 50 is connected to the elastic membrane 30, and the top of the electrical connection component 50 is connected to the power supply 200, so as to transmit current through the electrical connection component 50 and the conductive elastic membrane 30 to the wafer mounted below the elastic membrane 30.

[0089] Furthermore, the electrical connection assembly 50 includes an upper conductive rod 51 and a lower conductive rod 52, as shown in FIG7, and a spring pin structure 53 is detachably connected between the two to adjust the length of the electrical connection assembly 50.

[0090] In Figure 7, the spring-loaded pin structure 53 includes a spring 531 and a pin 532, which are interlocked and abut against the grooves on the opposing surfaces of the upper conductive rod 51 and the lower conductive rod 52. The pin 532 is partially inserted into the inside of the spring 531 to serve as a connection and positioning element. Specifically, the lower part of the pin 532 has a smaller diameter and is inserted into the inner ring of the spring 531, so that the end of the spring 531 abuts against the shoulder of the pin 532.

[0091] In this invention, the electrical connection assembly 50 further includes a protective assembly 54, which is disposed on the outside of the upper conductive rod 51 and the lower conductive rod 52 to prevent liquid from entering the interior of the electrical connection assembly 50. Simultaneously, the protective assembly 54 can prevent other metal components from connecting with the upper conductive rod 51 and the lower conductive rod 52 and causing a short circuit, thereby ensuring the normal use of the bearing head 100.

[0092] Furthermore, the protective component 54 includes a first protective sleeve 541 and a second protective sleeve 542, wherein the first protective sleeve 541 is disposed on the outside of the upper conductive rod 51, and the second protective sleeve 542 is disposed on the outside of the lower conductive rod 52.

[0093] In the embodiment shown in Figure 7, the lower end of the first protective sleeve 541 is basically flush with the lower end of the upper conductive rod 51, while the length of the second protective sleeve 542 is greater than the length of the lower conductive rod 52, allowing the second protective sleeve 542 to extend upwards to cover the lower conductive rod 52 and the spring pin structure 53. The first protective sleeve 541 and the second protective sleeve 542 are vertically overlapped and sleeved together, and a gap is provided between them, so that the spring pin structure 53 can adaptively adjust the length of the electrical connection assembly 50, thereby preventing the first protective sleeve 541 and the second protective sleeve 542 from interfering with each other and interfering with the free extension and contraction of the spring 531.

[0094] A conductive disk 55 is disposed below the lower conductive rod 52, as shown in Figure 6. The conductive disk 55 includes a conductive rod 551 and a disk base 552 as shown in Figure 8, which are integrally formed. The conductive rod 551 is threaded to the lower conductive rod 52, and the disk base 552 is bonded to the elastic membrane 30 with adhesive, so that the current can be conducted along the conductive terminal 56, the upper conductive rod 51, the spring pin structure 53, the lower conductive rod 52 and the conductive disk 55 to the elastic membrane 30, and finally to the wafer mounted on the elastic membrane 30.

[0095] To ensure conductivity between the conductive disk 55 and the elastic membrane 30, a conductive adhesive is used. In some embodiments, the conductive adhesive used to bond the conductive disk 55 and the elastic membrane 30 is a silicone-based conductive adhesive, such as Dow Corning SE 4420 conductive adhesive. This adhesive has good flexibility, is suitable for applying dynamic loads, and exhibits high-temperature resistance, maintaining good adhesion within a temperature range of -50°C to 200°C to adapt to the operating environment of electrochemical mechanical polishing (EMP). Specifically, during EMP, the wafer generates a large amount of heat, which is conducted to the elastic membrane 30 and the conductive disk 55. If the adhesive cannot withstand high temperatures, it will affect the reliability of the bond between the conductive disk 55 and the elastic membrane 30, and may even cause an open circuit in the electrical connection assembly 50, thereby affecting the normal operation of the carrier head 100.

[0096] Figure 9 is a schematic diagram of a first protective sleeve 541 provided in an embodiment of the present invention. The first protective sleeve 541 includes a flange 5411 and a sleeve 5412, which are integrally formed to form a tubular structure, thereby protecting the upper conductive rod 51. The flange 5411 is fixed to the end of the positioning hole 11 (shown in Figure 6), and the sleeve 5412 is disposed in the electrical connection assembly mounting hole 211 of the shaft portion 21.

[0097] Furthermore, a gap 57 is provided between the lower end face of the flange 5411 and the top surface of the shaft 21. When the bearing plate 20 moves vertically up and down, the top surface of the shaft 21 will not come into contact with the flange 5411 of the first protective sleeve 541, so as to avoid component interference of the bearing head 100 during operation.

[0098] In Figure 9, the flange 5411 is provided with a vertical vent 5413, one end of which is connected to the air source and the other end is connected to the electrical connection assembly mounting hole 211, so as to vent or evacuate the central chamber 39 of the elastic membrane 30, thereby changing the load applied to the central chamber 39.

[0099] That is, during electrochemical mechanical polishing, the pressure in the central chamber 39 can be controlled, and the polishing load applied to the wafer surface can be adjusted, so that mechanical polishing and electrochemical reaction are combined to comprehensively regulate the material removal rate on the wafer surface.

[0100] The bottom of the second protective sleeve 542 is provided with a snap-fit ​​groove 5421, as shown in Figure 10. The annular protrusion 351 of the fixing rib 35 of the elastic membrane 30 is set in the snap-fit ​​groove 5421 to further ensure the reliability of the fixation between the two.

[0101] This utility model also provides an electrochemical mechanical polishing system 1000, the schematic diagram of which is shown in Figure 11. The electrochemical mechanical polishing system 1000 includes:

[0102] The polishing disc 300 is used to fix the polishing pad 400; specifically, the polishing pad 400 is positioned above the polishing disc 300 so that the polishing pad 400 can rotate synchronously with the polishing disc 300.

[0103] The liquid supply assembly 500 is disposed above the polishing disk 300 for supplying polishing liquid toward the surface of the polishing pad 400;

[0104] And the carrier head 100 shown in Figure 6, used to load the wafer and abut the wafer against the surface of the polishing pad 400;

[0105] A power supply 200 is connected at one end to the electrical connection component 50 of the carrier head 100 and at the other end to the polishing pad 400, so that the wafer to be polished is in the electric field formed between the elastic film 30 and the polishing liquid.

[0106] In this invention, the polishing pad 400 is provided with multiple vertical through holes to retain polishing fluid on its surface. The polishing fluid is an electrolyte containing abrasive particles, such as SiO2, CeO2, and / or Al2O3, to combine electrochemical reaction with mechanical polishing, thereby increasing the material removal rate of the wafer, adapting to the polishing of materials with high hardness, and improving the polishing efficiency of the wafer.

[0107] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application.

[0108] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. An elastic membrane for electrochemical mechanical polishing, characterized in that, include: A disc-shaped base plate portion; an upright portion extending vertically upward along the edge of the base plate portion; the upright portion being provided with at least one horizontal rib; a partition rib extending upward along the base plate portion and located inside the upright portion to divide the elastic membrane into multiple chambers; a mounting hole being provided at the center of the base plate portion, and a fixing rib being provided along the inner edge of the mounting hole to connect an electrical connection assembly of an electrochemical polishing bearing head, the electrical connection assembly being disposed between the elastic membrane and the electrode of the power source.

2. The elastic membrane according to claim 1, characterized in that, The fixing rib is a ring structure that extends horizontally toward the center of the base plate, and the length of the fixing rib is less than or equal to 1 / 2 of the inner diameter of the mounting hole.

3. The elastic membrane according to claim 1, characterized in that, The wall thickness of the fixing rib is 1 / 4 to 1 / 2 of the thickness of the base plate, and an annular protrusion is provided at the end facing the center of the elastic membrane. The annular protrusion extends vertically along the end of the fixing rib.

4. The elastic membrane according to claim 1, characterized in that, The base plate, upright section, and partition ribs are made of silicone rubber or neoprene rubber, and the base plate contains more than or equal to 50% silver powder.

5. The elastic membrane according to claim 1, characterized in that, The bottom surface of the base plate is provided with an annular groove, and a matching annular conductive sheet is bonded to the inside of the annular groove.

6. The elastic membrane according to claim 5, characterized in that, The annular groove is provided at the partition rib of the adjacent chamber, and its depth is 0.2 to 0.5 mm.

7. The elastic membrane according to claim 1, characterized in that, The bottom surface of the base plate is pre-embedded with conductive blocks, which are circular, rectangular, triangular and / or elliptical in shape and are evenly distributed.

8. The elastic membrane according to claim 7, characterized in that, The conductive block is disposed at the partition rib of the adjacent chamber.

9. The elastic membrane according to claim 1, characterized in that, The dividing rib includes a vertical section and a horizontal section, which are integrally formed; the horizontal section is located above the fixing rib.

10. A support head for electrochemical polishing, characterized in that, include: A coupling disk with a positioning hole at its center; a carrier disk with a matching shaft portion slidably connected to the positioning hole, allowing the carrier disk to rotate with the coupling disk and / or move vertically; an elastic membrane as described in any one of claims 1 to 9, disposed below the carrier disk for loading the wafer to be processed; a retaining ring disposed below the carrier disk and located on the outer periphery of the elastic membrane; and an electrical connection assembly vertically disposed in a mounting hole along the shaft portion, one end of which is connected to a power source, and the other end of which is connected to the central cavity of the elastic membrane, such that the wafer to be processed is placed in an electric field formed between the elastic membrane and the polishing fluid.

11. The bearing head according to claim 10, characterized in that, At least a portion of the electrical connection assembly is a flexible element that extends and retracts vertically to accommodate the deformation of the elastic membrane, thereby creating a stable electric field between the elastic membrane and the polishing fluid.

12. The bearing head according to claim 11, characterized in that, The electrical connection assembly includes an upper conductive rod and a lower conductive rod, which are detachably connected by a spring-loaded pin structure to adjust the length of the electrical connection assembly; the spring-loaded pin structure includes a spring and a pin shaft, which are engaged together and abut against the grooves on the opposite surfaces of the upper and lower conductive rods.

13. The bearing head according to claim 12, characterized in that, A conductive disk is disposed below the lower conductive rod, which includes a conductive rod and a disk base, both integrally formed; the conductive rod is connected to the lower conductive rod, the conductive rod passes through the mounting hole, and the top surface of the disk base is bonded to the fixing rib of the elastic membrane by conductive adhesive.

Images