Polishing apparatus and substrate polishing method

Abstract

A polishing apparatus according to the present disclosure includes: a processing container configured as a processing space for providing a vacuum atmosphere; a substrate holding unit disposed in the processing container and configured to hold a substrate to be processed; a pad holding part disposed so as to face the substrate holding part and configured so as to hold a pad for polishing the substrate; a slurry supply unit configured to supply a slurry, which is an ionic liquid, to the surface of the substrate or the pad; and a pressurizing head configured to pressurize the substrate holding portion or the pad holding portion, one of the substrate holding portion and the pad holding portion being pressurized so that the substrate and the pad come into contact with each other, and the substrate holding portion and the pad holding portion respectively rotate the substrate and the pad in a state in which the slurry is supplied.

Description

Technical Field

[0001] The present disclosure relates to a polishing device and a polishing method for a substrate. Background Art

[0002] A semiconductor wafer polishing device is disclosed, comprising a polishing platen for holding a polishing cloth and a wafer holding portion for holding a wafer to be polished, a polishing endpoint detection portion within the polishing platen, and a portion for measuring the slurry temperature during polishing within the endpoint detection portion (Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-363229 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present disclosure provides a polishing device and a substrate polishing method capable of suppressing undesired oxidation of a substrate surface after polishing.

[0008] Solutions for solving problems

[0009] A polishing device according to one embodiment of the present disclosure includes: a processing container configured to provide a processing space with a vacuum atmosphere; a substrate holding portion arranged in the processing container and configured to hold a substrate to be processed; a pad holding portion arranged to be opposite to the substrate holding portion and configured to hold a pad for polishing the substrate; a slurry supply portion configured to supply slurry as an ionic liquid to the surface of the substrate or the pad; and a pressurizing head portion configured to pressurize the substrate holding portion or the pad holding portion, one of the substrate holding portion and the pad holding portion being pressurized so that the substrate contacts the pad, and the substrate holding portion and the pad holding portion rotate the substrate and the pad relative to each other while being supplied with the slurry.

[0010] Effects of the Invention

[0011] According to the present disclosure, it is possible to suppress unintended oxidation of the surface of a polished substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a cross-sectional view showing an example of a substrate processing apparatus according to the first embodiment of the present disclosure.

[0013] Figure 2 This is a schematic cross-sectional view showing an example of the polishing device according to the first embodiment.

[0014] Figure 3 This is a diagram showing an example of the state of the substrate during the polishing step of the first embodiment.

[0015] Figure 4 This is a flowchart showing an example of the substrate polishing method according to the first embodiment.

[0016] Figure 5 This is a schematic cross-sectional view showing an example of a polishing device according to the second embodiment. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the disclosed polishing apparatus and substrate polishing method will be described in detail with reference to the accompanying drawings. It should be noted that the disclosed technology is not limited to the following embodiments.

[0018] Conventionally, in the process of planarizing metals such as copper formed on a substrate, CMP (Chemical Mechanical Polishing) was performed in the atmosphere. CMP performed in the atmosphere uses a slurry (polishing liquid) in which abrasive particles are dispersed in an aqueous solution or an oxidizing agent is added. However, since these processes are performed in the atmosphere, an oxide film is formed on the surface of the metal after polishing. Therefore, it is necessary to remove the oxide film in a subsequent process. In order to solve these problems, the present invention aims to suppress the undesirable oxidation of the substrate surface after CMP by performing CMP in a vacuum atmosphere. However, since when CMP is performed in a vacuum atmosphere using the same slurry as in the atmosphere, solvents such as water evaporate from the slurry, resulting in friction exceeding expectations, and the polishing rate becomes excessive, or the cooling effect brought about by the slurry cannot be obtained, making it difficult to perform proper polishing.

[0019] (First embodiment)

[0020] [Configuration of Substrate Processing Apparatus 1]

[0021] Figure 1 This is a cross-sectional view showing an example of a substrate processing apparatus according to the first embodiment of the present disclosure.

[0022] Figure 1 The substrate processing apparatus 1 shown is a substrate processing apparatus capable of performing various processes such as polishing and plasma processing on substrates (eg, semiconductor wafers) individually.

[0023] The substrate processing apparatus 1 includes an apparatus body 2 and a control device 11 for controlling the apparatus body 2. For example, Figure 1As shown, the apparatus main body 2 includes a vacuum transfer chamber 3, a polishing apparatus 10, multiple process modules 13, multiple load lock modules 15, and an EFEM (Equipment Front End Module) 18. It should be noted that in the following description, the vacuum transfer chamber 3 is also referred to as a VTM (Vacuum Transfer Module) 3, the process module 13 is also referred to as a PM (Process Module) 13, and the load lock module 15 is also referred to as an LLM (Load Lock Module) 15.

[0024] The VTM3 has a roughly quadrilateral shape when viewed from above. A polishing device 10 and multiple PMs 13 are connected to two opposing sides of the VTM3. Furthermore, an LLM 15 is connected to one of the other two opposing sides of the VTM3. The VTM3 includes a vacuum chamber and a robot arm 12 disposed within it.

[0025] The robot arm 12 is configured to be freely rotatable, retractable, and elevating. The robot arm 12 can transport the substrate between the polishing device 10, PM 13, and LLM 15 by placing the substrate on a fork disposed at the front end. The robot arm 12 is an example of a vacuum transport robot. It should be noted that the robot arm 12 is not limited to Figure 1 The configuration shown only needs to be able to transfer the substrate between the polishing device 10 , PM 13 , and LLM 15 .

[0026] The polishing apparatus 10 comprises a processing chamber and a substrate holder disposed therein. After the substrate is held by the substrate holder, the polishing apparatus 10 supplies slurry in a vacuum environment and polishes the substrate using a pad. The VTM 3 is separated from the polishing apparatus 10 by a freely openable and closable gate valve 23. The details of the polishing apparatus 10 will be described later.

[0027] PM13 has a processing chamber and a cylindrical table (loading table) arranged inside. After the substrate is placed on the table, PM13 introduces processing gas under a reduced pressure inside, and then applies high-frequency power to the inside to generate plasma, and uses the plasma to perform plasma treatment on the substrate. VTM3 and PM13 are separated by a gate valve 14 that can be opened and closed freely. That is, the substrate polished by the polishing device 10 is transferred to PM13 via VTM3 in a vacuum atmosphere, so that it can be transferred to PM13 in a state that suppresses undesirable oxidation of the substrate surface after polishing.

[0028] The LLM15 is located between the VTM3 and the EFEM18. The LLM15 has a variable internal pressure chamber that can switch between vacuum and atmospheric pressure, and a cylindrical stage located within it. When transferring a substrate from the EFEM18 to the VTM3, the LLM15 maintains its interior at atmospheric pressure while receiving the substrate from the EFEM18. The pressure is then reduced to atmospheric pressure before transferring the substrate to the VTM3. Furthermore, when transferring a substrate from the VTM3 to the EFEM18, the LLM15 maintains its interior at vacuum while receiving the substrate from the VTM3. The pressure is then raised to atmospheric pressure before transferring the substrate to the EFEM18. The LLM15 is separated from the VTM3 by a freely openable and closable gate valve 16. Furthermore, the LLM15 is separated from the EFEM18 by a freely openable and closable gate valve 17.

[0029] EFEM18 is configured to be opposite to VTM3. EFEM18 is in the shape of a rectangular parallelepiped and is equipped with an FFU (Fan Filter Unit), which is an atmospheric transfer chamber maintained at an atmospheric pressure atmosphere. Three LLM15 are connected to one side of the EFEM18 along the long dimension. Five loading ports (LP: Load Port) 19 are connected to the other side of the EFEM18 along the long dimension. A FOUP (Front-Opening Unified Pod) (not shown), which is a container for accommodating multiple substrates, is placed in the LP19. An atmospheric transfer robot (robotic arm) (not shown) for transferring substrates is configured in the EFEM18. EFEM18 is an example of a loading module.

[0030] The control device 11 includes a memory, a processor, and an input / output interface. The memory stores programs executed by the processor and recipes including conditions for each process. The processor executes the programs read from the memory and controls various components of the substrate processing apparatus 1 via the input / output interface based on the recipes stored in the memory.

[0031] It should be noted that LLM15 is an LLM and grinding device, which has the same functions and equipment as the grinding device 10. Figure 1 A new PM13 is set at the position of the polishing device 10. Alternatively, the polishing device 10 may be set adjacent to the EFEM18 of the atmospheric pressure inert atmosphere, and after the prescribed polishing is performed by the polishing device 10, the substrate is transported to the LLM15 via the EFEM18 of the inert atmosphere, thereby Figure 1 A new PM 13 is installed at the position of the polishing device 10. At this time, the substrate is transported between the polishing device 10 and the EFEM 18 using the robot arm in the EFEM 18.

[0032] [Configuration of the polishing device 10]

[0033] Figure 2 This is a schematic cross-sectional view showing an example of the polishing device according to the first embodiment. Figure 2 The illustrated polishing device 10 is configured as a polishing device utilizing a face-down mechanism, for example.

[0034] The polishing apparatus 10 includes a chamber 20 , an exhaust mechanism 30 , a quadrupole mass spectrometer (QMS) 40 , a rotary table 50 , a pressurizing head 60 , a slurry supply unit 70 , and a cleaning liquid supply unit 80 .

[0035] An opening 22 is formed in the side wall 21 of the chamber 20, through which the substrate W passes. The opening 22 is opened and closed by a gate valve 23. Furthermore, an exhaust mechanism 30 is connected to the upper portion of the side wall 21 via an exhaust port 24. Furthermore, a quadrupole mass spectrometer 40 is connected to the upper portion of the side wall 21 via a pipe 25. A rotary table 50 is disposed approximately in the center of the bottom surface 26 of the chamber 20. Furthermore, a recovery tank 27 for recovering the slurry is connected around the rotary table 50 on the bottom surface 26.

[0036] A pressurizing head 60, a pad conditioning unit 62, and pipes 64 and 65 are provided on the inner side of the upper surface 28 of the chamber 20. Furthermore, a slurry supply unit 70 and a cleaning liquid supply unit 80 are provided on the outer side of the upper surface 28 of the chamber 20. It should be noted that the chamber 20 is an example of a processing vessel.

[0037] The exhaust mechanism 30 is provided with a vacuum pump and a pressure control valve. In one embodiment, the exhaust mechanism 30 is configured to adjust the pressure in the chamber 20 by controlling the vacuum pump and the pressure control valve. As the vacuum pump, for example, a dry vacuum pump, a turbomolecular pump, etc. can be used.

[0038] The quadrupole mass spectrometer 40 measures changes in the partial pressures of the ionic liquid constituting the slurry supplied from the slurry supply unit 70 and degassing components originating from the polishing material on the substrate W. The quadrupole mass spectrometer 40 outputs the measured values ​​to the control device 11. It should be noted that the measured values ​​of the quadrupole mass spectrometer 40 are used to detect the processing endpoint of the substrate W.

[0039] The turntable 50 includes a holding portion 51 for holding a pad and a pad 52. The holding portion 51 is arranged to face the substrate holding portion 61, which is provided at the front end of the pressure head 60 and holds the substrate W to be processed. The pad 52 is a pad for polishing the substrate W. The pad 52 can be made of, for example, a non-woven fabric containing foamed urethane, polyester fiber, and urethane, suede, acrylic, and Al2O3. In addition, the pad 52 can also be made of a fixed abrasive pad with abrasive grains embedded in the pad, or a semi-fixed abrasive pad with abrasive grains embedded in a mesh resin. The turntable 50 can polish the substrate W to be processed by CMP by rotating at, for example, 10 to 300 rpm. In addition, a recovery cup 53 for recovering slurry is provided around the turntable 50. The upper portion of the recovery cup 53 is tilted toward the turntable 50 to suppress splashing of slurry and cleaning liquid. Note that the recovery cup 53 can be moved in the vertical direction by a driving mechanism, and can be moved downward when the substrate W is loaded or unloaded, thereby enabling the substrate W to be loaded or unloaded from the opening 22 .

[0040] The pressure head 60 has a substrate holding portion 61 at the lower front end portion. The substrate holding portion 61 holds the substrate W in such a manner that the polished surface of the substrate W to be processed becomes an orientation opposite to the turntable 50. The substrate holding portion 61 holds the substrate W by, for example, an electrostatic chuck, a mechanical chuck, or the surface tension of an ionic liquid in a backing material such as foamed urethane moistened with an ionic liquid. The pressure head 60 can move in the up and down directions, press the substrate W held on the substrate holding portion 61 against the pad 52 of the turntable 50, and, for example, rotate the turntable 50 and the pressure head 60 at 10 to 300 rpm, thereby being able to polish the substrate W to be processed by CMP. That is, the holding portion 51 is configured in such a manner that the surface of the pad 52 becomes the upper surface, and the substrate holding portion 61 is configured to hold the substrate W in such a manner that the polished surface of the substrate W becomes the lower surface, and the substrate holding portion 61 is pressurized in the downward direction by the pressure head 60, thereby polishing the substrate W. It should be noted that Figure 2 This shows a case where a metal film and a dielectric film such as an oxide are both present on the surface of the substrate W, but it may also be a case where only a metal film or only a dielectric film is present on the surface.

[0041] The pad conditioning section 62 includes a grinding stone 63 at its lower front end. The pad conditioning section 62 is movable in the vertical direction and presses the grinding stone 63 against the pad 52 to thereby grind the surface of the pad 52 and refresh the surface of the pad 52.

[0042] The slurry supply unit 70 is connected to the pipe 64 that penetrates the upper surface 28 of the chamber 20 via the pipe 71. The slurry supply unit 70 is equipped with multiple ionic liquid tanks equipped with vacuum degassing mechanisms for the ionic liquid, multiple liquid delivery pumps, and multiple pH adjustment units. In one embodiment, the slurry supply unit 70 is configured to supply at least one slurry from the ionic liquid tanks equipped with vacuum degassing mechanisms for the ionic liquid via the corresponding liquid delivery pumps and pH adjustment units into the chamber 20. In other words, the slurry supply unit 70 is configured to dropwise supply the ionic liquid slurry from the pipe 64 onto the pad 52 within the chamber 20.

[0043] The chamber 20 is in a vacuum atmosphere, so the slurry supply unit 70 supplies the slurry to the front end valve of the piping 64 by a liquid delivery pump that applies mechanical pressure such as a diaphragm method, a tubing method, or a capacity calculation type pump. The front end valve is an example of an ejection unit. In the front end valve of the piping 64, the plunger mechanically moves to suck and eject a certain amount of slurry, thereby supplying the slurry from the front end valve to the chamber 20. The opening and closing of the front end valve can also use a needle valve type or a stop valve type. It should be noted that the front end valve can also include a syringe. In addition, the slurry supply unit 70 can also be a slit provided at the front end of the piping 64 to replace the valve to supply the slurry. The supply amount of the slurry is measured, for example, by a flow sensor using ultrasound provided in the piping 71, a mass meter provided in the ionic liquid tank in the slurry supply unit 70, and a mass meter provided on the rotating table 50. It should be noted that the slurry recovered by the recovery cup 53 is stored in the recovery tank 27 by gravity. The slurry stored in the recovery tank 27 can also be recovered for reuse, for example, during the treatment interval. It should be noted that the slurry stored in the recovery tank 27 can also be circulated in the grinding process by, for example, a pump (not shown) that can apply mechanical pressure.

[0044] The cleaning liquid supply unit 80 is connected to the pipe 65 that penetrates the upper surface 28 of the chamber 20 via the pipe 81. The cleaning liquid supply unit 80 is equipped with multiple ionic liquid tanks equipped with vacuum degassing mechanisms for ionic liquids, multiple liquid delivery pumps, and multiple pH adjustment units. In one embodiment, the cleaning liquid supply unit 80 is configured to supply at least one cleaning liquid from the ionic liquid tanks equipped with vacuum degassing mechanisms for ionic liquids via corresponding liquid delivery pumps into the chamber 20. In other words, the cleaning liquid supply unit 80 is configured to drip the cleaning liquid, which is an ionic liquid, from the pipe 65 onto the pad 52 within the chamber 20.

[0045] The chamber 20 is in a vacuum atmosphere, so the cleaning liquid supply unit 80 supplies the cleaning liquid to the front end valve of the piping 65 through a liquid delivery pump that applies mechanical pressure, such as a diaphragm type, a pipeline type, or a volumetric type pump. In the front end valve of the piping 65, the plunger mechanically operates to suck in and eject a certain amount of cleaning liquid, thereby supplying the cleaning liquid from the front end valve to the chamber 20. The front end valve can also be opened and closed using a needle valve type or a stop valve type. It should be noted that the front end valve can also include a syringe. In addition, the cleaning liquid supply unit 80 can also be provided with a slit at the front end of the piping 65 to supply the cleaning liquid instead of a valve. The supply amount of the cleaning liquid is measured, for example, by a flow sensor using ultrasound provided in the piping 81, a mass meter provided in the ionic liquid tank in the cleaning liquid supply unit 80, and a mass meter provided on the rotating table 50. It should be noted that the cleaning liquid recovered by the recovery cup 53 is stored in a recovery tank 27 different from the slurry. That is, a valve (not shown) is provided at the inlet of the recovery tank 27, and the valve is controlled to recover the slurry and the cleaning liquid into different recovery tanks 27. The cleaning liquid stored in the recovery tank 27 can also be recovered for reuse during treatment intervals.

[0046] The control device 11 controls the various components of the polishing apparatus 10 to perform the following substrate polishing method. To give a detailed example, the control device 11 controls the polishing apparatus 10 to perform a process of holding a substrate W in the substrate holding portion 61 within the chamber 20. The control device 11 controls the polishing apparatus 10 to perform the following process: moving the pressurizing head 60 in a direction perpendicular to the substrate W so that the substrate W contacts the pad 52 and applies pressure, and supplying slurry to rotate the substrate W and the pad 52 to polish the substrate W. The control device 11 controls the polishing apparatus 10 to perform a process of detecting the processing endpoint of the substrate W based on a measurement value that changes as the substrate W is polished. The control device 11 controls the polishing apparatus 10 to perform a process of supplying a cleaning liquid and removing the slurry and cleaning liquid by spin drying by rotating the pressurizing head 60. The control device 11 controls the polishing apparatus 10 to perform a process of removing the substrate W held by the pressurizing head 60 from the chamber 20.

[0047] Next, use Figure 3 The role of the slurry in the polishing process (CMP) will be described. Figure 3 This is a diagram showing an example of the state of the substrate during the polishing step of the first embodiment. Figure 3The substrate W in state 101 is shown in a state where a metal film 111 is formed on a silicon substrate 110. State 101 is the state before the start of the polishing process. By starting polishing and supplying slurry onto the substrate W, a film 112 as an oxide film or a complex film is formed on the metal film 111 as shown in state 102. At this time, the slurry plays the role of an oxidizing agent, a dispersant for abrasive particles, cooling the substrate W, and lubricating the substrate W and the pad 52. Then, when mechanical polishing is performed by the abrasive particles in the slurry or the pad, the pressure of the substrate holding portion 61, and the rotation of the substrate W and the pad 52, the surface of the metal film 111 is flattened as shown in state 103. In state 103, a slurry that acts as an anti-corrosion agent may also be added to the surface of the polished metal film 111. It should be noted that in this embodiment, the ionic liquid used in the slurry also acts as a dispersant, so a dispersant does not need to be added separately. It should be noted that during the transition from state 101 to state 102, oxygen and water may be introduced into chamber 20 under controlled conditions, causing the surface of metal film 111 to be transformed into film 112, which is an oxide film. The oxygen and water are then removed by vacuuming, and then slurry is supplied. In this process, the slurry acts as a coolant for substrate W, a dispersant for abrasive particles, and a lubricant between substrate W and pad 52. Mechanical polishing is then performed using the abrasive particles in the slurry or pad, the pressure applied by substrate holder 61, and the rotation of substrate W and pad 52. As shown in state 103, the surface of metal film 111 is flattened.

[0048] [Ionic Liquids]

[0049] Next, the ionic liquid used in the slurry supplied by the slurry supply unit 70 will be described. The ionic liquid used in the slurry is an ionic compound that is liquid at room temperature and is changed according to the material of the polishing object on the substrate W. For example, when the polishing object is SiO2, W, or Al, the ionic liquid used in the slurry is an acidic ionic liquid. Examples of acidic ionic liquids include protic ionic liquids, HSO4 ionic liquids having a sulfonic group in the anion, and the like. － ionic liquids having sulfonic groups, ionic liquids having sulfonic groups in cations, ionic liquids having sulfonic groups in anions and cations, and the like.

[0050] As a protic ionic liquid, for example, ethylammonium nitrate represented by chemical formula (D1) can be used. － Examples of the ionic liquid that can be used include 1-butyl-3-methylimidazolium hydrogen sulfate (Bmim-HSO 4 ) represented by the chemical formula (D2) and 1-ethyl-3-methylimidazolium hydrogen sulfate (Emim-HSO 4 ) represented by the chemical formula (D3).

[0051]

[0052] Examples of ionic liquids having a sulfonic group in the cation include 1-(4-sulfobutyl)-3-methylimidazoliumbis(trifluoromethanesulfonyl)imide represented by chemical formula (D4) and 1-(4-sulfobutyl)-3-methylimidazoliumtrifluoromethanesulfonate represented by chemical formula (D5).

[0053]

[0054] As the ionic liquid having a sulfonic group in the anion and the cation, for example, 1-methyl-3-(4-sulfobutyl)imidazolium hydrogen sulfate represented by the chemical formula (D6) can be used.

[0055]

[0056] In addition, acidic ionic liquids such as Emim-AlCl4 and Bmim-AlCl4 can be used as anions containing AlCl4. － Furthermore, acidic ionic liquids can use Hmim-Cl or the like as anions having Cl － of ionic liquids.

[0057] For example, when the polishing target material is SiOC, an alkaline ionic liquid is used in the slurry. Examples of alkaline ionic liquids include those whose anions are acetic acid. Examples of alkaline ionic liquids whose anions are acetic acid include 1-ethyl-3-methylimidazolium acetate (Emim-AcO) and 1-butyl-3-methylimidazolium acetate (Bmim-AcO).

[0058] For example, when the polishing target material is Cu, the ionic liquid used in the slurry is an ionic liquid that forms a Cu complex film. Examples of ionic liquids that form a Cu complex film include ionic liquids obtained by adding quinaldic acid to the following ionic liquids.

[0059] Regarding various ionic liquids, examples of cations constituting the ionic liquids include cations of the pyridinium type, imidazolium type, ammonium type, pyrrolidinium type, piperidinium type, and phosphonium type containing phosphorus. These cations include alkyl-(CH2) n CH3 as the side chain.

[0060] Examples of pyridinium cations include C2py represented by the chemical formula (C1-1): + , C4py represented by chemical formula (C1-2) + , but are not limited to these.

[0061]

[0062] Examples of imidazolium cations include C2mim represented by the chemical formula (C2-1): + 、C4mim represented by chemical formula (C2-2) + 、C6mim represented by chemical formula (C2-3) + 、C8mim represented by chemical formula (C2-4) + , but are not limited to these.

[0063]

[0064] Examples of ammonium cations include: N represented by the chemical formula (C3-1): 3，1，1，1 + 、N shown in chemical formula (C3-2) 4，1，1，1 + 、N shown in chemical formula (C3-3) 6，1，1，1 + 、N shown in chemical formula (C3-4) 2，2，1，(2O1) + 、Ch represented by chemical formula (C3-5) + , but are not limited to these.

[0065]

[0066] Examples of the pyrrolidinium type cation include Pyr represented by the chemical formula (C4-1): 1，3 + 、Pyr represented by chemical formula (C4-2) 1，4 + , but are not limited to these.

[0067]

[0068] Examples of piperidinium cations include Pip represented by the chemical formula (C5-1):1，3 + 、Pip represented by chemical formula (C5-2) 1，4 + , but are not limited to these.

[0069]

[0070] Examples of the phosphonium type cation include P represented by the chemical formula (C6-1): 5，2，2，2 + , P represented by the chemical formula (C6-2) 6，6，6，14 + , but are not limited to these.

[0071]

[0072] Examples of anions constituting the ionic liquid include TfO represented by the chemical formula (A1): － , Tf2N represented by chemical formula (A2) － (TFSA － ), Tf3C represented by chemical formula (A3) － , FSA represented by chemical formula (A4) － , CH3COO represented by chemical formula (A5) － CF3COO represented by chemical formula (A6) － , BF4 represented by chemical formula (A7) － PF6 represented by chemical formula (A8) － 、(CN)2N represented by chemical formula (A9) － 、AlCl4 represented by chemical formula (A10) － 、Al2Cl7 shown in chemical formula (A11) － , but are not limited to these.

[0073]

[0074] Specific examples of the ionic liquid include tributylhexadecylphosphonium 3-(trimethylsilyl)-1-propanesulfonate (BHDP-DSS) and N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate (DEME-BF 4 ).

[0075] Examples of the ionic liquid used in the slurry when functioning as an oxidizing agent include ionic liquids containing 2-iodooxybenzoic acid (IBX), etc. Examples of the ionic liquid containing IBX include the ionic liquid represented by chemical formula (B1).

[0076]

[0077] Examples of the ionic liquid used in the slurry when functioning as an anticorrosive agent include ionic liquids containing benzotriazole (BTA), etc. Examples of the ionic liquid containing BTA include an ionic liquid represented by chemical formula (B2).

[0078]

[0079] In addition, the ionic liquid used in the slurry may also contain abrasive particles. The abrasive particles are responsible for mechanical planarization. Types of abrasive particles include oxides, sulfides, and other abrasive particles. The abrasive particles may also be composite materials thereof. In addition, abrasive particles with a particle size of 200 nm or less are used. Examples of oxide abrasive particles include SiO2, CeO2, Al2O3, ZrO2, MnO2, Mn2O3, SnO2, TiO2, Cr2O, Fe2O3, NiO, and ZnO. Examples of sulfide abrasive particles include FeS and CuS. Examples of other abrasive particles include B4C, diamond, c-BN, SiC, polymer abrasive particles, ionic liquid crystals with a liquid crystal structure, and ionic crystals with a solid ionic liquid. It should be noted that when a fixed abrasive pad or a semi-fixed abrasive pad containing these abrasive particles is used as the pad 52, the slurry may not contain abrasive particles.

[0080] [Substrate polishing method]

[0081] Next, the substrate polishing method according to the first embodiment will be described. Figure 4 This is a flowchart showing an example of the substrate polishing method according to the first embodiment.

[0082] The control device 11 controls the exhaust mechanism 30 to control the pressure in the chamber 20 to a predetermined pressure (e.g., 10 －5 Pa). It should be noted that the vacuum atmosphere in this embodiment is set to also include a pressure atmosphere lower than the normal atmospheric pressure. The control device 11 opens the opening 22 by controlling the gate valve 23. When the opening 22 is opened, the substrate W is moved into the processing space of the chamber 20 through the opening 22 and is held in the substrate holding portion 61. That is, the control device 11 controls the polishing device 10 to hold the substrate W in the substrate holding portion, i.e., the substrate holding portion 61, in the chamber 20 (process S1). The control device 11 closes the opening 22 by controlling the gate valve 23. It should be noted that the outside of the opening 22 is connected to the VTM3 maintained at the same pressure (vacuum atmosphere) as that in the chamber 20.

[0083] The control device 11 starts supplying slurry onto the pad 52 by controlling the slurry supply unit 70. The control device 11 controls the pressure head 60 to pressurize the pressure head 60 so that the substrate W contacts the pad 52. In addition, the control device 11 controls the rotating table 50 and the pressure head 60 to rotate the substrate W and the pad 52 to polish the substrate W (step S2). It should be noted that the control device 11 can also control the slurry supply unit 70 during polishing to first supply a slurry containing an oxidant to form an oxide film on the substrate W, and then switch to a slurry without an oxidant to remove the formed oxide film. In addition, the control device 11 can also control the processing gas supply mechanism (not shown) to supply an oxygen-containing gas, a water-containing gas or a nitrogen-containing gas into the chamber 20, thereby oxidizing or nitriding the surface of the substrate W, and then removing the formed oxide film or nitride film. Furthermore, the control device 11 can also control the power supply (not shown) to use the ionic liquid (slurry) between the substrate W and the pad 52 as an electrolyte to electrolytically polish the substrate W.

[0084] The control device 11 receives input from the quadrupole mass spectrometer 40 of measurement values ​​that change as the substrate W is polished. The control device 11 detects the processing endpoint of the substrate W based on the input measurement values. It should be noted that the control device 11 may also detect the processing endpoint of the substrate W based on various measurement values, such as the torque of the turntable 50 and the pressing head 60, the reflectivity of the surface of the substrate W, and the resistance of the ionic liquid between the turntable 50 and the pressing head 60. Furthermore, after detecting the processing endpoint of the substrate W, the control device 11 may control the slurry supply unit 70 to supply an ionic liquid containing an anticorrosive agent onto the pad 52.

[0085] When the processing endpoint of substrate W is detected, the control device 11 controls the slurry supply unit 70 to stop supplying slurry and controls the cleaning liquid supply unit 80 to start supplying cleaning liquid. The control device 11 controls the turntable 50 and the pressure head 60 to rotate the substrate W and the pad 52 to clean the substrate W (step S3). After controlling the cleaning liquid supply unit 80 to stop supplying cleaning liquid, the control device 11 controls the pressure head 60 to separate the substrate W from the pad 52, and removes the residual slurry and cleaning liquid by spin drying the substrate holding unit 61. It should be noted that the control device 11 can also control a heater (not shown) to increase the temperature of the substrate W to reduce the viscosity of the cleaning liquid after controlling the cleaning liquid supply unit 80 to stop supplying cleaning liquid, and then perform spin drying. In addition, as in the polishing device 210 described below, when the polished surface of the substrate W faces upward, the control device 11 can also control the cleaning liquid supply unit 80 to stop supplying cleaning liquid and then supply another ionic liquid with good wettability, replace the cleaning liquid with the ionic liquid, and then perform spin drying.

[0086] When the cleaning and drying of the substrate W are completed, the control device 11 opens the opening 22 by controlling the gate valve 23. When the opening 22 is opened, the substrate W is carried out of the chamber 20 through the opening 22 by the robot arm 12 of the VTM3. That is, the control device 11 controls the substrate processing device 1 to carry the substrate W held by the substrate holding portion 61 out of the chamber 20 (step S4). The carried-out substrate W is directly transported to the next step such as a plasma processing device under a vacuum atmosphere, for example, while maintaining a vacuum state. As described above, since an ionic liquid that is not easily volatile in a vacuum atmosphere is used as a slurry and the substrate W is polished in a vacuum, oxidation of the polished substrate W due to exposure to the atmosphere can be suppressed.

[0087] (Second embodiment)

[0088] In the first embodiment described above, a polishing device 10 using a face-down mechanism is used. However, a polishing device using a face-up mechanism may also be used. This embodiment will be described as a second embodiment. It should be noted that in the polishing device of the second embodiment, components identical to those of the first embodiment are denoted by the same reference numerals, and descriptions of the overlapping components and operations will be omitted.

[0089] Figure 5 This is a schematic cross-sectional view showing an example of a polishing device according to the second embodiment. Figure 5 The polishing apparatus 210 shown is installed in the substrate processing apparatus 1 instead of the polishing apparatus 10 of the first embodiment. The polishing apparatus 210 includes a chamber 220, a rotating table 250, and a press head 260 instead of the chamber 20, the rotating table 50, and the press head 60 of the first embodiment. Each component of the polishing apparatus 210 is controlled by the control device 11.

[0090] An opening 222 for passing the substrate W is formed in the side wall 221 of the chamber 220. The opening 222 is opened and closed by a gate valve 223. Furthermore, an exhaust mechanism 30 is connected to the upper portion of the side wall 221 via an exhaust port 224. Furthermore, a quadrupole mass spectrometer 40 is connected to the upper portion of the side wall 221 via a pipe 225. A rotary table 250 is disposed approximately in the center of the bottom surface 226 of the chamber 220. Furthermore, a recovery tank 227 for recovering the slurry is connected to the periphery of the rotary table 250 on the bottom surface 226. Furthermore, a pad conditioning unit 262 is provided on the outer periphery of the bottom surface 226 relative to the recovery tank 227.

[0091] A pressurizing head 260 and pipes 264 and 265 are provided inside the upper surface 228 of the chamber 220. Furthermore, a slurry supply unit 70 and a cleaning liquid supply unit 80 are provided outside the upper surface 228 of the chamber 220. The chamber 220 is an example of a processing vessel.

[0092] The turntable 250 has a substrate holding portion 251. The substrate holding portion 251 holds the substrate W to be processed and is arranged in a manner opposite to the pressure head 260. The substrate holding portion 251 holds the substrate W by, for example, a mounting surface having a recessed portion capable of mounting the substrate W, an electrostatic chuck, a mechanical chuck, or the surface tension of an ionic liquid in a backing material such as foamed urethane wetted with an ionic liquid. The turntable 250 can grind the substrate W to be processed by CMP by rotating at, for example, 10 to 300 rpm. In addition, a recovery cup 253 for recovering the slurry is provided around the turntable 250. It should be noted that the recovery cup 253 can be moved in the up and down directions by a driving mechanism, and can be moved in and out of the substrate W from the opening 222 by moving downward when the substrate W is carried in and out.

[0093] The pressure head 260 has a holding portion 261 for holding a pad and a pad 252 at the lower front end. The pad 252 held by the holding portion 261 is arranged to face the rotating table 250. The pad 252 is a pad for grinding the substrate W, for example, it can grind the radius of the substrate W. In addition, the pressure head 260 can also be moved in the radial direction of the substrate W ( Figure 5 The substrate W is polished by moving the pressure head 260 in the vertical and horizontal directions. It should be noted that a plurality of pressure heads 260 may be provided, and a plurality of pads 252 may be used to polish the substrate W. The pad 252 may be made of, for example, non-woven fabric containing foamed urethane, polyester fiber and urethane, suede, acrylic, and Al2O3. In addition, the pad 252 may be made of a fixed abrasive pad having abrasive grains embedded in the pad or a semi-fixed abrasive pad having abrasive grains embedded in a mesh resin. The pressure head 260 is capable of moving in the vertical and horizontal directions. The pressure head 260 presses the pad 252 held by the holding portion 261 against the substrate W on the turntable 250, and for example rotates the turntable 250 and the pressure head 260 at 10 to 300 rpm, thereby enabling the substrate W to be polished by CMP. That is, the substrate holding portion 251 is configured so that the polished surface of the substrate W becomes the upper surface, and the holding portion 261 is configured to hold the pad 252 so that the surface of the pad 252 becomes the lower surface, and the pad 252 is pressurized downward by the pressure head 260, thereby polishing the substrate W in a vacuum.

[0094] The pad conditioning unit 262 has a grindstone 263 on its upper surface. The pad conditioning unit 262 is rotatable, and the pad 252 of the pressing head 260 moved onto the grindstone 263 is pressed against the grindstone 263, thereby grinding and renewing the surface of the pad 252.

[0095] The slurry supply unit 70 is connected to the pipe 264 that passes through the upper surface 228 of the chamber 220 via the pipe 71. In other words, the slurry supply unit 70 is configured to dropwise supply the slurry, which is an ionic liquid, from the pipe 264 onto the substrate W within the chamber 220. It should be noted that the slurry recovered by the recovery cup 253 is stored in the recovery tank 227 by gravity. It should be noted that the slurry stored in the recovery tank 227 can also be circulated during the polishing process by, for example, a pump (not shown) that can apply mechanical pressure.

[0096] The cleaning liquid supply unit 80 is connected to the pipe 265 that passes through the upper surface 228 of the chamber 220 via the pipe 81. That is, the cleaning liquid supply unit 80 is configured to drip the cleaning liquid, which is an ionic liquid, onto the substrate W from the pipe 265 within the chamber 220. It should be noted that the cleaning liquid recovered by the recovery cup 253 is stored in a recovery tank 227 that is different from the slurry. In other words, a valve (not shown) is provided at the inlet of the recovery tank 227. When the slurry is recovered and when the cleaning liquid is recovered, the valve is controlled so that the recovery is carried out into different recovery tanks 227.

[0097] In the polishing apparatus 210, the substrate polishing method can be performed in a vacuum, except that the position of holding the substrate W is different from that of the polishing apparatus 10 of the first embodiment. As described above, the substrate W is polished in a vacuum atmosphere even in the polishing apparatus 210, thereby suppressing oxidation of the polished substrate W due to exposure to the atmosphere.

[0098] It should be noted that while the second embodiment described above uses the size of the pad 252 as the radius of the substrate W, this is not limiting. For example, the pad 252 can be configured to be large enough to polish the entire surface of the substrate W, that is, larger than the diameter of the substrate W. In this case, the pipes 264 and 265 can be connected to a showerhead-like flow path provided within the pad 252, through which the slurry and cleaning liquid are introduced onto the surface of the substrate W. This allows the surface of the substrate W to be polished to a flatter surface than in the second embodiment.

[0099] As described above, according to each embodiment, the polishing apparatus 10, 210 includes a processing container (chamber 20), a substrate holding portion (substrate holding portion 61, 251), a pad holding portion (holding portion 51, 261), a slurry supply portion 70, and a pressurizing head portion 60, 260. The processing container is configured to provide a processing space having a vacuum atmosphere. The substrate holding portion is disposed in the processing container and is configured to hold a substrate W to be processed. The pad holding portion is disposed opposite to the substrate holding portion and is configured to hold a pad 52, 252 for polishing the substrate W. The slurry supply portion 70 is configured to supply a slurry as an ionic liquid to the surface of the substrate W or the pad 52. The pressurizing head portion 60, 260 is configured to pressurize the substrate holding portion or the pad holding portion. In addition, one of the substrate holding portion and the pad holding portion is pressurized so that the substrate W contacts the pad 52, 252, and the substrate holding portion and the pad holding portion rotate the substrate W and the pad 52, 252 relative to each other while being supplied with the slurry. As a result, the polished substrate surface is not exposed to the atmosphere before proceeding to the next step, thereby suppressing oxidation of the polished substrate.

[0100] Furthermore, according to each embodiment, the slurry supply unit 70 supplies the slurry by applying mechanical pressure. As a result, the slurry can be supplied even when the chamber 20 is in a vacuum atmosphere.

[0101] Furthermore, according to each embodiment, the slurry supply unit 70 supplies the slurry using a diaphragm type, a pipe type, or a volumetric type pump. As a result, the slurry can be supplied even when the chamber 20 is in a vacuum atmosphere.

[0102] Furthermore, according to various embodiments, the polishing apparatus 10, 210 is further connected to a slurry supply unit 70, which includes a discharge unit for discharging slurry onto the surface of the substrate W or the pad 52, 252. The discharge unit is a syringe equipped with a needle valve or a stop valve, or a slit. As a result, slurry can be supplied to the surface of the substrate W or the pad 52, 252 even when the chamber 20 is in a vacuum atmosphere.

[0103] In addition, according to each embodiment, the substrate holding portion holds the substrate W by using an electrostatic chuck, a mechanical chuck, or the surface tension of an ionic liquid in a backing material such as urethane foam wetted with the ionic liquid. As a result, the substrate W can be held even when the chamber 20 is in a vacuum atmosphere.

[0104] Furthermore, according to each embodiment, the slurry contains abrasive grains, and as a result, the substrate W can be mechanically polished and flattened.

[0105] Furthermore, according to each embodiment, the pads 52 and 252 contain abrasive grains. As a result, the substrate W can be mechanically polished and flattened.

[0106] In addition, according to each embodiment, the polishing apparatus 10 or 210 further includes a cleaning liquid supply unit 80 configured to supply a cleaning liquid, such as an ionic liquid, to the surface of the substrate W or the pad 52. Furthermore, the substrate holder removes the slurry and cleaning liquid by spin drying. As a result, the surface of the polished substrate W can be kept clean.

[0107] Furthermore, according to the first embodiment, the pad holding portion is configured so that the surface of the pad 52 is the upper surface. Furthermore, the substrate holding portion is configured to hold the substrate W so that the polished surface of the substrate W is the lower surface, and to apply downward pressure by the pressure head 60. As a result, the parallelism of the surface of the substrate W can be further improved.

[0108] Furthermore, according to each embodiment, the polishing apparatus 10 or 210 is further configured to surround the pad holding portion or the substrate holding portion and include a recovery cup 53 or 253 for recovering the slurry. As a result, the slurry can be reused.

[0109] Furthermore, according to the second embodiment, the substrate holding portion 251 is arranged so that the polished surface of the substrate W is the upper surface. Furthermore, the pad holding portion is configured to hold the pad 252 so that the surface of the pad 252 is the lower surface, and to apply downward pressure by the pressing head 260. As a result, the polishing apparatus 210 can be miniaturized.

[0110] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive, and may be omitted, replaced, or modified in various ways without departing from the scope of the appended claims and their spirit.

[0111] Furthermore, in each of the above-described embodiments, spin drying is performed after cleaning the substrate W, but this is not limiting. For example, without using abrasives, the substrate W can be transferred to a plasma processing apparatus under a vacuum atmosphere, where dry etching using hydrogen plasma or other methods can be used to remove liquids such as cleaning liquid. Furthermore, for example, a brush (not shown) can be used to remove liquids such as cleaning liquid remaining on the surface of the substrate W. Furthermore, for example, a nozzle (not shown) can be used to perform differential pressure blowing using a small amount of nitrogen-containing gas.

[0112] Furthermore, in each of the above-described embodiments, the substrate W is loaded into the polishing apparatus 10 or 210 from the vacuum atmosphere of the VTM 3, but the present invention is not limited thereto. For example, the substrate W may be loaded into the polishing apparatus 10 or 210 from a transfer chamber in an atmospheric atmosphere, and the polishing process may be performed after the pressure is reduced to a vacuum atmosphere after loading.

[0113] It should be noted that the present disclosure may also adopt the following configurations. (1)

[0115] A polishing device comprises: a processing container configured to provide a processing space with a vacuum atmosphere; a substrate holding portion arranged in the processing container and configured to hold a substrate to be processed; a pad holding portion arranged to be opposite to the substrate holding portion and configured to hold a pad for polishing the substrate; a slurry supply portion configured to supply slurry as an ionic liquid to the surface of the substrate or the pad; and a pressurizing head portion configured to pressurize the substrate holding portion or the pad holding portion, one of the substrate holding portion and the pad holding portion being pressurized so that the substrate contacts the pad, and the substrate holding portion and the pad holding portion rotate the substrate and the pad relative to each other while being supplied with the slurry. (2)

[0117] The polishing device according to the above (1), wherein the slurry supply unit supplies the slurry by applying mechanical pressure. (3)

[0119] The polishing device according to (2) above, wherein the slurry supply unit supplies the slurry using a diaphragm type, a pipe type, or a volumetric type pump. (4)

[0121] The polishing device according to (3) above further comprises a discharge portion connected to the slurry supply portion and discharging the slurry onto the surface of the substrate or the pad, wherein the discharge portion is a syringe having a needle valve or a stop valve, or a slit. (5)

[0123] The polishing apparatus according to any one of (1) to (4) above, wherein the substrate holding portion holds the substrate by an electrostatic chuck, a mechanical chuck, or surface tension of the ionic liquid. (6)

[0125] The polishing device according to any one of (1) to (5) above, wherein the slurry contains abrasive grains. (7)

[0127] The polishing device according to any one of (1) to (5) above, wherein the pad contains abrasive grains. (8)

[0129] The polishing device according to any one of (1) to (7) above further comprises a cleaning liquid supply unit configured to supply a cleaning liquid serving as an ionic liquid to the surface of the substrate or the pad, wherein the substrate holding unit removes the slurry and the cleaning liquid by spin drying. (9)

[0131] A polishing device according to any one of (1) to (8) above, wherein the pad holding portion is configured so that the surface of the pad becomes the upper surface, and the substrate holding portion is configured to hold the substrate so that the polished surface of the substrate becomes the lower surface, and is pressurized in the downward direction by the pressure head. (10)

[0133] The polishing device according to the above (9) further comprises a recovery cup for recovering the slurry, wherein the recovery cup is configured to surround the pad holding portion. (11)

[0135] A polishing device according to any one of (1) to (8) above, wherein the substrate holding portion is configured so that the polished surface of the substrate becomes the upper surface, and the pad holding portion is configured to hold the pad so that the surface of the pad becomes the lower surface, and is pressurized in a downward direction by the pressure head. (12)

[0137] The polishing device according to the above (11) further includes a recovery cup for recovering the slurry, and the recovery cup is configured to surround the substrate holding portion. (13)

[0139] A method for polishing a substrate comprises the following steps: holding a substrate on a substrate holding portion, the substrate holding portion being arranged in a processing container and holding the substrate to be processed; pressurizing the substrate holding portion or the pad holding portion in such a manner that a pad for polishing the substrate contacts the substrate, and supplying a slurry as an ionic liquid to the surface of the substrate or the pad, causing the substrate and the pad to rotate relative to each other to polish the substrate in a vacuum, wherein the pad is held by the pad holding portion arranged in such a manner as to be opposed to the substrate holding portion; detecting a processing end point of the substrate based on a measured value that changes due to the polishing of the substrate; supplying a cleaning liquid as an ionic liquid to the surface of the substrate or the pad, removing the slurry and the cleaning liquid by spin drying the substrate holding portion; and moving the substrate held on the substrate holding portion out of the processing container.

[0140] Description of Reference Numerals

[0141] 1: substrate processing device; 10, 210: polishing device; 11: control device; 20, 220: chamber; 27, 227: recovery tank; 30: exhaust mechanism; 40: quadrupole mass spectrometer; 50, 250: turntable; 51, 261: holding part; 52, 252: pad; 53, 253: recovery cup; 60, 260: pressurizing head; 61, 251: substrate holding part; 62, 262: pad dressing part; 70: slurry supply part; 80: cleaning liquid supply part; W: substrate.

Claims

1. A grinding device, wherein: have: A processing container configured to provide a processing space with a vacuum atmosphere; a substrate holding portion disposed in the processing container and configured to hold a substrate to be processed; a pad holding portion disposed opposite to the substrate holding portion and configured to hold a pad for polishing the substrate; a slurry supply unit configured to supply slurry as an ionic liquid to a surface of the substrate or the pad; as well as a pressurizing head configured to pressurize the substrate holding portion or the pad holding portion, One of the substrate holding portion and the pad holding portion is pressed so that the substrate comes into contact with the pad, and the substrate holding portion and the pad holding portion relatively rotate the substrate and the pad in a state where the slurry is supplied.

2. The grinding device according to claim 1, wherein The slurry supply part supplies the slurry by applying mechanical pressure.

3. The grinding device according to claim 2, wherein: The slurry supply unit supplies the slurry using a diaphragm type, a pipeline type, or a volumetric type pump.

4. The grinding device according to claim 3, wherein Also features: a discharge part connected to the slurry supply part and discharging the slurry onto the surface of the substrate or the pad; The ejection portion is a syringe equipped with a needle valve or a stop valve, or a slit.

5. The grinding device according to claim 1, wherein The substrate holding portion holds the substrate by an electrostatic chuck, a mechanical chuck, or surface tension of the ionic liquid.

6. The grinding device according to claim 1, wherein The slurry contains abrasive particles.

7. The grinding device according to claim 1, wherein The pad contains abrasive particles.

8. The grinding device according to claim 1, wherein Also features: a cleaning liquid supply unit configured to supply a cleaning liquid as an ionic liquid to the surface of the substrate or the pad; The substrate holding portion removes the slurry and the cleaning liquid by spin drying.

9. The grinding device according to claim 1, wherein The pad holding portion is arranged so that the surface of the pad becomes the upper surface. The substrate holding portion is configured to hold the substrate such that the polished surface of the substrate becomes the lower surface, and is pressurized downward by the pressing head portion.

10. The grinding device according to claim 9, wherein Also features: The recovery cup for recovering the slurry is configured to surround the mat holding portion.

11. The grinding device according to claim 1, wherein The substrate holding portion is arranged so that the polished surface of the substrate becomes the upper surface. The pad holding portion is configured to hold the pad so that the surface of the pad becomes the lower surface, and to be pressed downward by the pressing head portion.

12. The grinding device according to claim 11, wherein Also features: A recovery cup for recovering the slurry is configured to surround the substrate holding portion.

13. A method for polishing a substrate, wherein: Has the following processes: holding a substrate on a substrate holding portion, the substrate holding portion being disposed in the processing container and holding the substrate to be processed; The substrate holding portion or the pad holding portion is pressurized so that a pad for polishing the substrate contacts the substrate, and a slurry of an ionic liquid is supplied to a surface of the substrate or the pad, and the substrate and the pad are rotated relative to each other to polish the substrate in a vacuum, wherein the pad is held by the pad holding portion disposed so as to face the substrate holding portion. detecting a processing endpoint of the substrate based on a measurement value that changes due to polishing of the substrate; supplying a cleaning liquid as an ionic liquid to the surface of the substrate or the pad, and removing the slurry and the cleaning liquid by spin drying the substrate holding portion; and The substrate held by the substrate holding portion is carried out from the processing container.

Images