Elastic film and bearing head for electrochemical mechanical polishing

Abstract

The invention 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; the fixing rib is of an annular structure and horizontally extends towards the center of the bottom plate part, and the length of the fixing rib is smaller than or equal to 1 / 2 of the inner diameter of the mounting hole.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductor manufacturing technology, and in particular, to an elastic film and a carrier head for electrochemical mechanical polishing. Background Art

[0002] The integrated circuit industry is the core of the information technology industry and plays a key role in boosting the transformation and upgrading of the manufacturing industry to digital and intelligent. A chip is the carrier of an integrated circuit, and chip manufacturing involves integrated circuit design, wafer manufacturing, wafer processing, electrical measurement, dicing and packaging, and testing processes. Among them, Electrochemical Mechanical Polishing (ECMP) is one of the manufacturing processes in wafer manufacturing.

[0003] As the semiconductor process node enters the nanoscale (such as below 5nm, 3nm), traditional CMP faces many bottlenecks, and ECMP has become a key technology supplement due to its unique synergistic mechanism. For example, when polishing SiC with high hardness, the efficiency of traditional CMP is extremely low, while ECMP generates an oxide layer in the electrolyte and mechanically removes the softened layer, effectively improving the material removal rate.

[0004] The carrier head of electrochemical machinery is an important part of the ECMP system, which is responsible for loading the wafer and immersing the wafer in the electrolyte; however, there are also some problems with the existing carrier heads of electrochemical machinery:

[0005] 1) The connection reliability between the elastic film of the carrier head and the electrode of the power supply is insufficient, which will affect the stability of the carrier head operation;

[0006] 2) The conductivity uniformity of the elastic film is insufficient, resulting in differences in the action effects of the electrolyte on each region of the wafer, and further affecting the material removal rate on the wafer surface. Summary of the Invention

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

[0008] According to the first aspect of the embodiments of the present application, an elastic film for electrochemical mechanical polishing is provided, which includes:

[0009] A disk-shaped bottom plate portion;

[0010] An upright portion extending vertically upward along the edge of the bottom plate portion; at least one horizontal rib is arranged on the upright portion;

[0011] A partition rib extending upward along the bottom plate portion and located inside the upright portion to divide the elastic film into a plurality of chambers;

[0012] An installation hole is disposed at the center of the bottom plate portion, and fixing ribs are disposed along the inner edge of the installation hole to connect the electrical connection components of the carrier head for electro - chemical polishing. The electrical connection components are disposed between the elastic membrane and the electrode of the power supply;

[0013] The fixing ribs are of an annular structure, which extend horizontally towards the center of the bottom plate portion. Moreover, the length of the fixing ribs is less than or equal to 1 / 2 of the inner diameter of the installation hole.

[0014] In some embodiments, the wall thickness of the fixing ribs is 1 / 4 - 1 / 2 of the thickness of the bottom plate portion, and an annular protrusion is disposed at the end of the fixing ribs towards the center of the elastic membrane. The annular protrusion extends vertically along the end of the fixing ribs.

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

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

[0017] In some embodiments, the annular groove is disposed at the partition ribs between adjacent chambers, and its depth is 0.2 - 0.5 mm.

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

[0019] In some embodiments, the conductive blocks are disposed at the partition ribs between adjacent chambers.

[0020] In some embodiments, the partition ribs include a vertical section and a horizontal section, which are integrally formed; the horizontal section is located above the fixing ribs.

[0021] According to the second aspect of the embodiments of the present application, a carrier head for electro - chemical polishing includes:

[0022] A coupling disk with a positioning hole disposed at the center;

[0023] A carrier disk, which is provided with a shaft portion in a matching manner. The shaft portion is slidably connected in the positioning hole, so that the carrier disk rotates with the coupling disk and / or moves in the vertical direction;

[0024] The above - mentioned elastic membrane, which is disposed below the carrier disk and is used for loading the wafer to be processed;

[0025] A retaining ring, which is disposed below the carrier disk and on the outer peripheral side of the elastic membrane;

[0026] The electrical connection component is vertically arranged in the mounting hole configured along the shaft portion. One end thereof is connected to the power supply, and the other end is connected to the central chamber of the elastic membrane, so that the wafer to be processed is in the electric field formed between the elastic membrane and the polishing liquid.

[0027] In some embodiments, at least part of the electrical connection component is a flexible member, which expands and contracts vertically to adapt to the deformation of the elastic membrane, thereby forming a stable electric field between the elastic membrane and the polishing liquid.

[0028] In some embodiments, the electrical connection component includes an upper conductive rod and a lower conductive rod, and a spring pin structure is detachably connected between the two to adjust the length of the electrical connection component; the spring pin structure includes a spring and a pin shaft, which are clamped together and abutted in the grooves on the opposite surfaces of the upper conductive rod and the lower conductive rod.

[0029] In some embodiments, a conduction disc is arranged below the lower conductive rod, which includes a conduction rod and a disc seat, and the two are integrally formed; the conduction rod is connected to the lower conductive rod, the conduction rod passes through the mounting hole, and the top surface of the disc seat is bonded to the fixing rib of the elastic membrane through a conductive adhesive.

[0030] The beneficial effects of the present invention include:

[0031] a. The provided elastic membrane is configured with a mounting hole for fixing the electrical connection component, and a fixing rib is arranged on the inner edge of the mounting hole to be connected to the clamping groove of the second protective sleeve through an annular protrusion, effectively ensuring the reliability of the fixation of the electrical connection component 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 flexibility to adjust the load applied by the electrical connection component to the polishing pad when the central chamber expands and contracts;

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

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

[0035] e. The Shore hardness of the elastic membrane is 55 to 65, so that the elastic membrane has a certain flexibility to facilitate the loading of the wafer by suction;

[0036] f. The surface of the bottom plate of the elastic membrane is provided with a plurality of annular grooves, and the surface of the bottom plate is also configured with rectangular grooves connecting adjacent annular grooves; the annular conductive sheet and the rectangular conductive sheet are metal foils, which are bonded to the bottom surface of the elastic membrane with a conductive adhesive to improve the conductivity uniformity of the elastic membrane without affecting its own flexibility;

[0037] g. The annular groove is arranged at the partition rib between adjacent chambers of the elastic membrane, which to a certain extent weakens the stress concentration at the partition rib of the elastic membrane, inhibits 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, so as to weaken the stress concentration at the partition rib;

[0039] i. A plurality of conductive blocks are embedded in the bottom surface of the elastic membrane to improve the conductive uniformity of the elastic membrane; the conductive blocks are circular, rectangular, triangular and / or elliptical, and are arranged at the partition ribs between adjacent chambers to weaken the stress concentration at the partition ribs of the elastic membrane, inhibit the pressure coupling between adjacent chambers, and ensure the accuracy of the polishing pressure applied to each chamber of the elastic membrane. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

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

[0042] Figure 2 is Figure 1 a partial enlarged view of part A in

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

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

[0045] Figure 5 It is a partial enlarged view of the bottom plate part provided by an embodiment of the present invention;

[0046] Figure 6 It is a schematic diagram of a carrier head for electrochemical mechanical polishing provided by an embodiment of the present invention;

[0047] Figure 7 is Figure 6 a partial enlarged view of part B in

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

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

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

[0051] Figure 11 It is a schematic diagram of an electrochemical mechanical polishing system provided by an embodiment of the present invention. Detailed implementation manners

[0052] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art shall fall within the scope of protection of the embodiments of the present application.

[0053] The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms of "a", "the" and "said" used in the present 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" 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 the present application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

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

[0056] A bottom plate portion 31, which has a disc-shaped structure, and the bottom thereof is used to load the wafer to be polished;

[0057] An upright portion 32, which extends vertically upward along the edge of the bottom plate portion 31; wherein, at least one horizontal rib 33 is arranged on the upright portion 32 to define the lateral position of the elastic membrane 30;

[0058] The partition ribs 34 extend upward along the bottom plate portion 31 and are located inside the upright portion 32 to divide the elastic membrane 30 into a plurality of chambers.

[0059] Figure 1 In the illustrated embodiment, the number of partition ribs 34 is three. Combined with the upright portion 32, they roughly divide the elastic membrane 30 into four independent chambers; two horizontal ribs 33 are arranged at the top of the upright portion 32, and an independent chamber is also formed between adjacent horizontal ribs 33.

[0060] In the present invention, a mounting hole 311 is arranged at the center of the bottom plate portion 31 for fixing the electrical connection component 50 of the carrier head 100 for electrochemical polishing ( Figure 6 shown), and the electrical connection component 50 is arranged between the elastic membrane 30 and the electrode of the power supply 200. That is, the electrical connection component 50 is arranged in the central chamber 39 of the elastic membrane 30, and the partition ribs 34 in the central region, together with the bottom plate portion 31 and the carrier plate 20 of the carrier head 100, enclose the central chamber 39.

[0061] Figure 2 is Figure 1 a partial enlarged view of A in the figure. A fixing rib 35 is arranged on the inner edge of the mounting hole 311. The fixing rib 35 is of an annular structure and extends horizontally towards the center of the bottom plate portion 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 flexibility to adjust the load of the electrical connection component 50 acting on the polishing pad when the central chamber 39 expands and compresses.

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

[0064] In the present invention, the bottom plate portion 31, the upright portion 32 and the partition ribs 34 of the elastic membrane 30 are made of silicone rubber or neoprene to take into account the flexibility and strength of the elastic membrane 30. Among them, the bottom plate portion 31 contains silver powder of 50% or more to ensure the conductivity of the part of the elastic membrane 30 in contact with the wafer. Specifically, when the elastic membrane 30 is molded, the silver powder needs to be evenly blended into the liquid rubber to form the bottom plate portion 31; then the undoped liquid rubber is poured in to form the upright portion 32 and the partition ribs 34, etc.

[0065] Furthermore, the Shore hardness of the elastic membrane 30 is 55 - 65, so that the elastic membrane 30 has a certain flexibility to facilitate the loading of the wafer by suction.

[0066] Figure 3 It is a bottom view of the elastic film 30 provided by an embodiment of the present invention. An annular groove 36 is provided on the bottom surface of the elastic film 30, that is, an annular groove 36 is provided on the lower surface of the bottom plate portion 31.

[0067] Furthermore, the number of the annular grooves 36 is multiple, and they are concentrically arranged on the bottom surface of the elastic film 30. A rectangular groove 37 is also arranged on the surface of the bottom plate portion 31 to communicate 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 to further improve the electrical conductivity uniformity of the bottom plate portion 31 of the elastic film 30.

[0069] It should be noted that the annular conductive sheet and the rectangular conductive sheet are metal thin sheets, and they are bonded to the bottom surface of the elastic film 30 with conductive adhesive to improve the electrical conductivity uniformity of the bottom plate portion 31 without affecting the flexibility of the bottom plate portion 31 itself.

[0070] In the present invention, the depths of the annular groove 36 and the rectangular groove 37 are 0.2 - 1.5 mm; preferably, the depths of the annular groove 36 and the rectangular groove 37 are 0.2 - 0.5 mm.

[0071] In some embodiments, the annular groove 36 is arranged at the partition rib 34 between adjacent chambers of the elastic film 30, which weakens the stress concentration at the partition rib 34 of the elastic film 30 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 film 30.

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

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

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

[0075] In some embodiments, the conductive blocks 38 are arranged at the partition rib 34 between adjacent chambers to weaken the stress concentration at the partition rib 34 of the elastic film 30, suppress the pressure coupling between adjacent chambers, and ensure the accuracy of the polishing pressure applied to each chamber of the elastic film 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 Figure 5 shown. By setting it in this way, the groove for placing the conductive block 38 is disposed inside the elastic film 30 to prevent the accumulation of particulate matter in the polishing liquid on the outer edge of the conductive block 38 to form crystals, and the falling of these crystals may cause scratches on the wafer.

[0077] Figure 2 In the illustrated embodiment, 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, there is a certain distance between the fixing rib 35 and the horizontal section 342 of the partition rib 34 to facilitate the installation and fixation of the electrical connection assembly 50.

[0078] Figure 6 is a schematic diagram of a carrier head 100 for electrochemical mechanical polishing provided by an embodiment of the present invention, Figure 7 is Figure 6 a partial enlarged view at B in

[0079] A coupling disk 10, which is of a disk-shaped structure. A connecting flange is provided above the coupling disk 10 to connect the output shaft of the driving motor, and further drive the coupling disk 10 and the connected components to rotate around the axis; a vertical positioning hole 11 is provided at the center of the coupling disk 10;

[0080] A carrier disk 20, on which a shaft portion 21 is provided above. The shaft portion 21 is arranged to match the positioning hole 11 of the coupling disk 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; meanwhile, the coupling disk 10 is connected to the carrier disk 20 through an annular film 60, so that the carrier disk 20 can rotate with the coupling disk 10 and / or move in the vertical direction; a through electrical connection component mounting hole 211 is provided inside the shaft portion 21, and it extends along the length direction of the shaft portion 21;

[0081] Figure 1 The elastic film 30 shown is disposed below the carrier disk 20 for loading the wafer to be processed; the elastic film 30 is fixed below the carrier disk 20 through a loading component 80, and the loading component 80 includes a loading disk and a loading ring, which fix the horizontal rib 33, the partition rib 34, etc. below the carrier disk 20 by means of a buckle;

[0082] A retaining ring 40 is disposed below the carrier disk 20 and on the outer peripheral side of the elastic film 30 to prevent the wafer to be polished from slipping out of the inside of the carrier head 100;

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

[0084] Further, one end of the electrical connection component 50 is connected to the power supply 200 ( Figure 11 shown), and the other end of the electrical connection component 50 is connected to the bottom plate portion 31 of the elastic membrane 30, so that the wafer to be processed is in the electric field formed between the elastic membrane 30 and the polishing liquid.

[0085] Generally, the positive electrode of the power supply 200 is connected to the wafer through the electrical connection component 50, so that the wafer enters the polishing liquid as an 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. At the same time of the electrochemical action, the abrasive grains in the polishing liquid physically grind the surface of the wafer to remove the passivation film or softening layer generated by the electrochemical reaction and expose the fresh surface for continuous dissolution.

[0086] The carrier head 100 further includes a pneumatic control component 70, as Figure 6 shown, which is communicated 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 component 70 generally includes functional devices such as a proportional valve, a flow meter, a pressure sensor, and a controller. For the connection relationship of each functional device, please refer to Patent CN110977750A, which will not be elaborated here.

[0087] To solve the problems such as wire pulling and tearing existing in the existing carrier head 100, at least part of the electrical connection component 50 provided by the present invention is a flexible member, which can expand and contract vertically to adapt to the deformation of the elastic membrane 30, and further form a stable electric field between the elastic membrane 30 and the polishing liquid to ensure the reliable operation of the carrier head 100.

[0088] Figure 7 In, the electrical connection component 50 is arranged 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 to transmit the current to the wafer loaded below the elastic membrane 30 through the electrical connection component 50 and the conductive elastic membrane 30.

[0089] Further, the electrical connection component 50 includes an upper conductive rod 51 and a lower conductive rod 52, as Figure 7 shown, and a spring pin structure 53 is detachably connected between the two to adjust the length of the electrical connection component 50.

[0090] Figure 7 In, the spring pin structure 53 includes a spring 531 and a pin shaft 532, which are clamped together and abutted in the grooves on the opposite surfaces of the upper conductive rod 51 and the lower conductive rod 52. The pin shaft 532 is partially inserted into the inside of the spring 531 to play a role of connection and positioning. That is, the diameter of the lower part of the pin shaft 532 is smaller, and it 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 shaft 532.

[0091] In the present invention, the electrical connection assembly 50 further includes a protection assembly 54, which is disposed outside the upper conductive rod 51 and the lower conductive rod 52 to prevent liquid from entering the interior of the electrical connection assembly 50. At the same time, the protection assembly 54 can prevent other metal components from connecting to the upper conductive rod 51 and the lower conductive rod 52 to cause a short circuit, thereby ensuring the normal use of the carrier head 100.

[0092] Furthermore, the protection assembly 54 includes Figure 9 the first protective sleeve 541 shown in Figure 10 and the second protective sleeve 542 shown in. Among them, the first protective sleeve 541 is disposed outside the upper conductive rod 51, and the second protective sleeve 542 is disposed outside the lower conductive rod 52.

[0093] Figure 7 In the illustrated embodiment, the lower end of the first protective sleeve 541 is substantially flush with the lower end of the upper conductive rod 51, and the length of the second protective sleeve 542 is greater than the length of the lower conductive rod 52, so that the second protective sleeve 542 can extend upward 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, and there is a gap between the two, 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 disturbing the free expansion and contraction of the spring 531.

[0094] A conduction disk 55 is disposed below the lower conductive rod 52. As Figure 7 shown, the conduction disk 55 includes a conduction rod 551 and a disk base 552. As Figure 8 shown, the two are integrally formed. Among them, the conduction rod 551 is threadedly connected to the lower conductive rod 52, and the disk base 552 is adhesively bonded to the elastic film 30 by glue, so that current can flow along the conductive terminal 56, the upper conductive rod 51, the spring pin structure 53, the lower conductive rod 52 and the conduction disk 55 to the elastic film 30, and finally conduct the current to the wafer loaded on the elastic film 30.

[0095] To ensure the electrical conductivity between the conductive disc 55 and the elastic membrane 30, the adhesive used is a conductive adhesive. In some embodiments, the conductive adhesive for bonding the conductive disc 55 and the elastic membrane 30 is a silicone-based conductive adhesive, such as Dow Corning SE 4420 conductive adhesive, which has good flexibility and is suitable for the application of dynamic loads. Moreover, this conductive adhesive has high-temperature resistance and can maintain good adhesiveness in the range of -50°C to 200°C to adapt to the operating environment of electrochemical mechanical polishing. Specifically, during electrochemical mechanical polishing, a large amount of heat is generated on the wafer, and this heat will be conducted to the elastic membrane 30 and the conductive disc 55. If the adhesive cannot withstand high temperatures, it will affect the reliability of the bonding between the conductive disc 55 and the elastic membrane 30, and even cause an open circuit in the electrical connection component 50, thereby affecting the normal operation of the carrier head 100.

[0096] Figure 9 FIG. 4 is a schematic view of the first protective sleeve 541 provided by 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. Among them, the flange 5411 is fixed to the end of the positioning hole 11 ( Figure 6 shown), and the sleeve 5412 is disposed in the electrical connection component mounting hole 211 of the shaft portion 21.

[0097] Further, a gap 57 is provided between the lower end surface of the flange 5411 and the top surface of the shaft portion 21. When the carrier plate 20 moves up and down vertically, the top surface of the shaft portion 21 will not abut against the flange 5411 of the first protective sleeve 541 to avoid component interference during the operation of the carrier head 100.

[0098] Figure 9 In FIG. 4, a vertical ventilation hole 5413 is configured on the flange 5411. One end of the ventilation hole 5413 is communicated with a gas source, and the other end is communicated with the electrical connection component mounting hole 211 to ventilate 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 of the central chamber 39 can be controlled to adjust the polishing load applied to the wafer surface, so that mechanical polishing and electrochemical reaction are combined to comprehensively control the material removal rate of the wafer surface.

[0100] A clamping groove 5421 is configured at the bottom of the second protective sleeve 542. As Figure 10 shown, the annular protrusion 351 of the fixing rib 35 of the elastic membrane 30 is disposed in the clamping groove 5421 to further ensure the reliability of the fixation between the two.

[0101] The present invention also provides an electrochemical mechanical polishing system 1000, and its schematic view is as Figure 11 shown. The electrochemical mechanical polishing system 1000 includes:

[0102] A polishing platen 300 is used to fix a polishing pad 400. Specifically, the polishing pad 400 is disposed above the polishing platen 300 such that the polishing pad 400 can rotate synchronously with the polishing platen 300.

[0103] A liquid supply assembly 500 is disposed above the polishing platen 300 for supplying polishing liquid onto the surface of the polishing pad 400.

[0104] And Figure 6 A shown carrier head 100 is used to load a wafer and press the wafer against the surface of the polishing pad 400.

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

[0106] In the present invention, the polishing pad 400 is configured with a plurality of vertical through holes to retain the polishing liquid on the surface of the polishing pad 400. The polishing liquid is an electrolyte containing abrasive grains, where the contained abrasive grains are SiO2, CeO2, and / or Al2O3, etc., to combine an electrochemical reaction with mechanical polishing, improve the material removal rate of the wafer, adapt to polishing of materials with higher hardness, and improve the polishing efficiency of the wafer.

[0107] Those of ordinary skill in the art can realize that the units and method steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A professional technician can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the embodiments of the present application.

[0108] The above embodiments are only used to illustrate the embodiments of the present application, rather than to limit the embodiments of the present application. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application, and the patent protection scope of the embodiments of the present application should be defined by the claims.

Claims

1. An elastic film for electrochemical mechanical polishing, characterized in that, include: A disc-shaped bottom plate; An upright portion extending vertically upward along an edge of the bottom plate portion; the upright portion is provided with at least one horizontal rib; A partition rib extending upwardly along the bottom plate portion and located inside the upright portion to divide the elastic membrane into a plurality of chambers; The center of the bottom plate is provided with a mounting hole, and the inner edge of the mounting hole is provided with a fixing rib to connect an electrical connection component of the electrochemical polishing carrier head, wherein the electrical connection component is arranged between the elastic membrane and the electrode of the power supply; The fixing rib is an annular structure, which is horizontally extended toward the center of the bottom plate, and the length of the fixing rib is less than or equal to 1 / 2 of the inner diameter of the mounting hole.

2. The elastic film according to claim 1, wherein The wall thickness of the fixing rib is 1 / 4 to 1 / 2 of the thickness of the bottom plate portion, and an annular protrusion is arranged at the end thereof facing the center of the elastic membrane, and the annular protrusion extends vertically along the end of the fixing rib.

3. The elastic film according to claim 1, wherein The bottom plate portion, the upright portion and the separation ribs are made of silicone rubber or chloroprene rubber, and the bottom plate portion contains greater than or equal to 50% of silver powder.

4. The elastic film according to claim 1, wherein The bottom surface of the bottom plate is provided with an annular groove, and the inside of the annular groove is bonded to a matching annular conductive sheet.

5. The elastic film according to claim 4, characterized in that, The annular groove is arranged at the dividing ribs of adjacent chambers, and its depth is 0.2-0.5 mm.

6. The elastic film according to claim 1, characterized in that, Conductive blocks are pre-buried on the bottom surface of the bottom plate portion. The conductive blocks are circular, rectangular, triangular and / or elliptical and are evenly distributed.

7. The elastic film according to claim 6, characterized in that, The conductive blocks are arranged at the dividing ribs of adjacent chambers.

8. The elastic film according to claim 2, characterized in that The separation rib comprises a vertical section and a horizontal section, which are integrally formed; the horizontal section is located above the fixing rib.

9. A carrier head for electrochemical polishing, characterized in that, include: A coupling plate, with a positioning hole at the center; The bearing plate is matched with a shaft portion, and the shaft portion is slidably connected to the positioning hole, so that the bearing plate rotates with the coupling plate and / or moves in the vertical direction; The elastic membrane according to any one of claims 1 to 8, arranged below a carrier plate, for loading wafers to be processed; A retaining ring, disposed below the carrier plate and located on the outer peripheral side of the elastic membrane; The electrical connection component is vertically arranged in the mounting hole arranged along the axis, one end of which is connected to the power supply, and the other end is connected to the central cavity of the elastic membrane, so that the wafer to be processed is in the electric field formed between the elastic membrane and the polishing liquid.

10. The carrier head according to claim 9, characterized in that, At least part of the electrical connection assembly is a flexible member, which expands and contracts vertically to adapt to the deformation of the elastic membrane, thereby forming a stable electric field between the elastic membrane and the polishing liquid.

11. The bearing head according to claim 10, characterized in that, The electrical connection assembly includes an upper conductive rod and a lower conductive rod, and a spring pin structure is detachably connected between the two to adjust the length of the electrical connection assembly; the spring pin structure includes a spring and a pin shaft, which are mutually clamped as a whole and abut against the grooves on the opposite surfaces of the upper conductive rod and the lower conductive rod.

12. The carrier head according to claim 11, wherein, A conductive disk is arranged below the lower conductive rod, which includes a conductive rod and a disk seat, which are 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 seat is bonded to the fixing ribs of the elastic membrane through conductive glue.

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