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WO2000037217A1 - Procede de nettoyage d'une surface abrasive - Google Patents

Procede de nettoyage d'une surface abrasive Download PDF

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Publication number
WO2000037217A1
WO2000037217A1 PCT/US1999/028816 US9928816W WO0037217A1 WO 2000037217 A1 WO2000037217 A1 WO 2000037217A1 US 9928816 W US9928816 W US 9928816W WO 0037217 A1 WO0037217 A1 WO 0037217A1
Authority
WO
WIPO (PCT)
Prior art keywords
applying
solution
acid solution
polishing
cleaning
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1999/028816
Other languages
English (en)
Inventor
Rajeev Bajaj
Bradley Withers
Rahul Surana
Stephen Jew
Wilbur C. Krusell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lam Research Corp
Original Assignee
Lam Research Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lam Research Corp filed Critical Lam Research Corp
Publication of WO2000037217A1 publication Critical patent/WO2000037217A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B53/00—Devices or means for dressing or conditioning abrasive surfaces
    • B24B53/017—Devices or means for dressing, cleaning or otherwise conditioning lapping tools
    • H10P52/403—

Definitions

  • This invention relates to a method for cleaning a polishing pad in a chemical-mechanical-polishing apparatus during semiconductor device fabrication.
  • CMP chemical-mechanical-polishing
  • the layer within the semiconductor device to be planarized is either an electrically insulating layer, or an electrical interconnect layer.
  • the abrasive force mills away the surface of the layer being planarized.
  • chemical compounds within the slurry undergo a chemical reaction with the components of the layer being planarized. The combination of the abrasive force created by the polishing pad and the chemical reaction within the slurry enhances the polishing rate.
  • the polishing process can be made more selective to one type of material than to another.
  • silicon dioxide is removed at a faster rate than, for example, boron nitride.
  • metals such as copper
  • commercially available copper slurry compositions typically include iron nitrates, ammonium salts, hydrogen peroxide, and the like.
  • a common requirement of all CMP processes is that the substrate be uniformly polished.
  • a uniform polishing rate is essential for the formation of a planar surface in the semiconductor device.
  • uniform polishing rates can be difficult to obtain, because, typically, there is a strong dependence of the polished removal rate on both the surface topography of the semiconductor substrate and equipment factors, such as the condition of the polishing pad, polishing pressure, and the like.
  • changes in the surface texture of the polishing pad during the polishing process reduce the degree of abrasiveness of the polishing pad.
  • reaction by-products generated in the polishing slurry, and other debris collect on the surface of the polishing pad.
  • the by-product materials fill micro- pores in the surface of the polishing pad, which is known as glazing.
  • polishing rate and removal variance decline.
  • polish removal rate can result in an incomplete removal of material from the semiconductor substrate.
  • CMP processing as in many other areas of semiconductor device fabrication, a change in the polishing rate and within wafer-non-uniformity make process control extremely difficult.
  • a constant polishing rate is desired in order to maintain precise controls on the polishing process.
  • the pad can be abraded by a conditioner, such as a steel brush or, a nylon brush. Additionally, periodic cleaning of the pad can be carried out using conditioning disks having a diamond abrasive embedded in a polymer matrix.
  • a conditioner such as a steel brush or, a nylon brush.
  • periodic cleaning of the pad can be carried out using conditioning disks having a diamond abrasive embedded in a polymer matrix.
  • metal by-products and polishing debris are removed from the surface of the pad by a mechanical grinding process in the presence of de-ionized water. If carried out vigorously, this process can result in removing material from the pad itself, in addition to reaction by-products and debris from the polishing process.
  • increased mechanical conditioning while maintaining the polishing rate, can reduce both planarization and pad life.
  • Frequent cleaning of the polishing pad can be beneficial in maintaining a constant polishing rate.
  • the polishing rate will typically be stable for process loads of about 500 to 1000 substrates.
  • the polish rate stability can decline rapidly where a metal, such as copper, is polished.
  • Many CMP processes show significant polish rate variability with as few as 25 to 50 semiconductor substrates even with frequent cleaning.
  • the rapid decline in the copper polishing rate can be very detrimental to the throughput and quality of a copper CMP process.
  • the copper CMP process is especially critical in copper metallization technology used in high performance microprocessor devices. Copper polishing slurries are formulated to oxidize copper and polish away localized areas of increased copper thickness, while not removing copper in localized areas of reduced thickness.
  • planarization is therefore achieved by preferential removal of copper-copper oxide from the localized areas of increased copper thickness.
  • improved processes are needed to maintain uniform copper polishing rates, and to increase the throughput of the copper CMP process.
  • the preferred embodiment described below is a method of operating a polishing apparatus in which a polishing slurry is applied to a polishing pad.
  • a semiconductor substrate having a metal layer thereon is subjected to metal polishing to remove portion of the metal layer.
  • the semiconductor substrate is removed from the polishing apparatus, and an acidic cleaning solution is applied to the polishing pad.
  • An abrasive force is then applied to the polishing pad in the presence of the acidic cleaning solution to remove metallic by-products and polishing debris from the surface of the polishing pad.
  • FIGS. 1 and 2 illustrate, in cross-section, processing steps for the removal of a copper layer from a semiconductor device using a CMP process in accordance with the invention
  • FIG. 3 is a perspective view of the operative portions of a single substrate CMP apparatus useful for practicing the invention.
  • FIG. 4 is a top view of the operative portions of a batch CMP apparatus useful for practicing the invention.
  • the present invention is for cleaning an abrasive surface, such as a polishing pad, in an abrasive metal removal apparatus.
  • the present invention is for a method of operating a polishing apparatus that provides an improved metal polishing process.
  • the operating method of the invention includes a pad cleaning process in which an acidic solution is used to remove metallic by-products, such as copper oxide, and corrosion inhibitors typically used in commercial copper polish slurries.
  • FIG. 1 in cross-section, is a portion of a semiconductor substrate 10 having various device components formed at the surface of the substrate.
  • the device components shown in FIG. 1 are merely representative of a vast number of different components used in an integrated circuit device. Accordingly, these components are only generally illustrated and are not meant to describe any particular type of semiconductor device.
  • the device components include, for example, gate electrodes 12 and 14, and a resistor 16 all residing on a surface 18 of semiconductor substrate 10.
  • a doped region 20 separates gate electrodes 12 and 14 along surface 18.
  • a first thick dielectric layer 22 overlies gate electrodes 12 and 14 and resistor 16.
  • a patterned metal interconnect layer 24 overlays dielectric layer 22 and a portion thereof makes contact with doped region 20 in semiconductor substrate 10.
  • a second dielectric layer 26 overlies metal interconnect layer 24 and first dielectric layer 22.
  • a copper layer 28 overlies second dielectric layer 26 and fills vials 30, 32, and 34.
  • FIG. 1 a general depiction of a multi-level metal interconnect structure.
  • electrical connections are provided in multiple overlying layers and each interconnect layer is separated by an inter level dielectric (ILD) material.
  • ILD inter level dielectric
  • a CMP process is carried out to form in-laid copper interconnects in vias and in trenches formed within the various ILD layers.
  • a CMP process is carried out to form the various in-laid copper interconnects, as illustrated in FIG. 2.
  • a planar surface 34 is formed across second dielectric layer 26.
  • the CMP process also forms an in-laid copper interconnect 36 and via studs 38, 40 and 42.
  • the CMP process removes substantially all of copper layer 28 overlying the upper surfaces of second dielectric layer 26, while not removing substantial portions of second dielectric layer 26.
  • This is known in the art as a selective polishing removal process, in which the polish removal rate of copper is substantially greater than the polish removal rate of a dielectric material, such as second dielectric layer 26.
  • reaction by-products and polish residues collect on the polishing pad of the CMP apparatus.
  • the reaction by-product formed during the polishing process is a copper oxide material in which copper bonds with oxygen in both the +1 and +2 oxidation states.
  • the copper oxide can be copper (I) oxide (Cu 2 O) and copper (II) oxide (CuO).
  • copper oxide by-products other residues can accumulate on a polishing pad during a copper polishing process, such as corrosion inhibitors, and the like.
  • benzotriazole (BTA) is included as a copper corrosion inhibitor.
  • the polishing rate substantially declines. ln a preferred embodiment of the invention, the rapid decline in the copper polishing rate is combated through the use of an acidic cleaning solution during operation of a CMP apparatus.
  • the copper oxide by-products are removed from the surface of the polishing pad, and either suspended within the polishing solution, or dissolved in the cleaning solution.
  • a CMP polishing apparatus is operated, in which a periodic cleaning process is carried out using an acidic solution.
  • a dilute hydrochloric acid solution is employed to remove copper oxide by-products from the surface of the polishing pad.
  • a dilute hydrochloric acid solution is preferred, those skilled in the art will appreciate that other inorganic and organic acid solutions can also be used to remove metallic residues, such as copper oxide.
  • other inorganic acid solutions can be used, such as a nitric acid solution, a sulfuric acid solution, a hydrofluoric acid solution, and the like.
  • an organic acid solution can also be used.
  • a dicarboxylic organic acid solution can be used to dissolve metal oxide residues.
  • dicarboxylic acid solutions include an oxalic acid solution, a tartaric acid solution, a malonic acid solution, and a phthallic acid solution, and the like.
  • a non-dicarboxylic acid solution can be used, such as a citric acid solution, and the like.
  • the metal oxide removing agents of the CMP cleaning solution can be an acid salt.
  • the acid salt can be an inorganic acid salt, or an organic acid salt.
  • the cleaning solution of the invention can be an inorganic or organic ammonium salt solution.
  • the present invention contemplates the removal of other transition metal oxides possessing similar chemical reactivity with an acidic solution.
  • transition metals within the group IB and MB groups of the periodic table can be expected to react in a similar manner in the presence of the inventive cleaning solution. Accordingly, it is within the scope of the present invention that any such group IB and IIB metal oxides can be removed from the surface of a polishing pad in accordance with the CMP operating method and cleaning process of the invention.
  • FIG. 3 is a perspective view of the operative portions of a single-substrate polishing apparatus 44.
  • Polishing apparatus 44 includes first and second drive cylinders 46 and 48 that turn a polishing pad 50 in a continuous looping motion.
  • a polishing wheel 52 is mechanically attached to and rotated by a shaft 54.
  • a workpiece, such as semiconductor substrate 10 is mounted to a flat surface of polishing wheel 52 and brought into abrasive contact with polishing pad 50 by a vertical motion of rotating shaft 54.
  • a platen resides directly beneath polishing pad 50 and resists the downward motion of rotating shaft 54.
  • a dispenser 58 is cantilevered over polishing pad 50 in proximity to first drive cylinder 46.
  • Dispenser 58 is configured to dispense both polishing slurry and cleaning solution during operation of polishing apparatus 44.
  • semiconductor substrate 10 is polished to remove a metal layer, such as copper layer 28.
  • a cleaning disk (not shown) is attached to polishing wheel 52.
  • acidic cleaning solution is dispensed by dispenser 58 onto polishing pad 50, as a cleaning disk abrasively contacts the polishing pad.
  • cleaning solution is dispensed at a rate of about 50 to 100 ml per minute.
  • polishing pad 50 is rotated at a rate of about 20 to 80 rpm.
  • a disk pressure of about 1 to 8 psi is applied by rotating shaft 54, while rotating the cleaning disk at about 5 to 80 rpm.
  • the cleaning process is carried out for a length of time sufficient to remove metal oxide residues and other polishing debris from the surface of polishing pad 50.
  • a cleaning process be carried out prior to the polishing of a semiconductor substrate.
  • the high volume operation of a polishing machine such as polishing apparatus 44, is typically carried out by the sequential polishing of many semiconductor substrates prior to the use of a cleaning cycle.
  • the process of the invention can be employed to initially condition a new polishing pad that has not previously been used to remove metal from semiconductor substrates.
  • the polishing process of the invention is carried out to insure removal of any debris and metal oxides that are inadvertently present on the surface of a new polishing pad.
  • the cleaning process of the invention can also be carried in a CMP operation using a batch polishing apparatus. Shown in FIG. 4 is a top view of an exemplary batch CMP apparatus 60.
  • a rotating polishing wheel 62 has a circular polishing pad 64 mounted thereon.
  • a retaining wall 66 is disposed about the periphery of polishing wheel 62.
  • a polishing slurry 68 is confined to a region about polishing pad 64 by retaining wall 66.
  • a plurality of semiconductor substrates 70 are positioned on two rotating support assemblies 72. Movable arms 74 bring semiconductor substrate 70 into contact with polishing pad 64.
  • polishing pad 64 rotates about an axis 78, while substrate supports 72 rotate as shown in FIG. 4.
  • a dispenser 80 is positioned to dispense polishing slurry and cleaning solution onto polishing pad 64.
  • polishing slurry 68 is replaced by an acidic cleaning solution and semiconductor substrate 70 are replaced by cleaning disks.
  • CMP apparatus 60 is operated, while dispensing about 20 to 1000 ml per minute of cleaning solution onto polishing pad 64.
  • the cleaning process is carried out using a cleaning disk pressure of about 1 to 2.5 psi and CMP apparatus 60 is operated for a period of time of about 10 to 120 seconds to remove metal oxides and other polishing debris from the surface of polishing pad 64.
  • polishing apparatus are generally descriptive of CMP machines commonly used for semiconductor device fabrication. Both the single-substrate apparatus and the batch apparatus typically have a polyurethane type polishing pad. Poly- urethane polishing pads can be abrasively cleaned by conditioning disks, or alternatively by a cleaning brush. The cleaning method of the invention can be carried out to clean a polyurethane type polishing pad with either conditioning disks, or with an abrasive brush.
  • the method of the invention can be applied to any abrasive removal process in which an abrasive surface is used in conjunction with a chemically reactive solution to remove a metal from a substrate surface.
  • an acidic solution such as hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and the like is applied to the abrasive surface and an abrasive force is generated against the abrasive surface.
  • the abrasive force is applied in the presence of a dilute hydrochloric acid solution to remove copper oxide from the abrasive surface.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Special Wing (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Cleaning Or Drying Semiconductors (AREA)

Abstract

L'invention porte sur un procédé de nettoyage d'une surface abrasive telle qu'un tampon à polir dans un appareil de polissage chimique-mécanique. Ce procédé consiste à appliquer une solution de nettoyage acide sur la surface abrasive, une force abrasive s'exerçant également sur cette surface abrasive pour retirer des sous-produits de réaction et traiter des débris provenant de cette surface abrasive. La solution de nettoyage acide réagit chimiquement aux sous-produits de réaction et, en concomitance avec la force abrasive, retire les sous-produits de réaction de la surface abrasive. Selon une réalisation préférée, un tampon à polir, utilisé pour retirer le cuivre d'un substrat semi-conducteur, est nettoyé avec une solution d'acide chlorhydrique dilué au moyen d'un disque de nettoyage qui se déplace par rotation contre la surface du tampon à polir.
PCT/US1999/028816 1998-12-21 1999-12-03 Procede de nettoyage d'une surface abrasive Ceased WO2000037217A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US21880498A 1998-12-21 1998-12-21
US09/218,804 1998-12-21

Publications (1)

Publication Number Publication Date
WO2000037217A1 true WO2000037217A1 (fr) 2000-06-29

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Application Number Title Priority Date Filing Date
PCT/US1999/028816 Ceased WO2000037217A1 (fr) 1998-12-21 1999-12-03 Procede de nettoyage d'une surface abrasive

Country Status (2)

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TW (1) TW431940B (fr)
WO (1) WO2000037217A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002014014A3 (fr) * 2000-08-11 2002-05-02 Rodel Inc Planarisation mechanico-chimique de substrats metalliques
EP1266956A1 (fr) * 2001-06-13 2002-12-18 JSR Corporation Composition de nettoyage d'un tampon à polir et méthode de nettoyage d'un tampon à polir
CN116988134A (zh) * 2023-07-17 2023-11-03 哈尔滨工业大学 一种搅拌摩擦增材制造成形工具清理装置及方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7354337B2 (en) * 2005-08-30 2008-04-08 Tokyo Seimitsu Co., Ltd. Pad conditioner, pad conditioning method, and polishing apparatus
CN112171513A (zh) * 2020-09-29 2021-01-05 合肥晶合集成电路股份有限公司 研磨垫处理方法及化学机械研磨设备

Citations (6)

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Publication number Priority date Publication date Assignee Title
JPH08255775A (ja) * 1995-03-15 1996-10-01 Toshiba Corp 半導体装置の製造方法及び半導体製造装置
US5692947A (en) * 1994-08-09 1997-12-02 Ontrak Systems, Inc. Linear polisher and method for semiconductor wafer planarization
US5773364A (en) * 1996-10-21 1998-06-30 Motorola, Inc. Method for using ammonium salt slurries for chemical mechanical polishing (CMP)
WO1998036045A1 (fr) * 1997-02-14 1998-08-20 Ekc Technology, Inc. Traitement post-nettoyage
US5823854A (en) * 1996-05-28 1998-10-20 Industrial Technology Research Institute Chemical-mechanical polish (CMP) pad conditioner
GB2324750A (en) * 1997-04-28 1998-11-04 Nec Corp Automatic wafer polishing apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5692947A (en) * 1994-08-09 1997-12-02 Ontrak Systems, Inc. Linear polisher and method for semiconductor wafer planarization
JPH08255775A (ja) * 1995-03-15 1996-10-01 Toshiba Corp 半導体装置の製造方法及び半導体製造装置
US5823854A (en) * 1996-05-28 1998-10-20 Industrial Technology Research Institute Chemical-mechanical polish (CMP) pad conditioner
US5773364A (en) * 1996-10-21 1998-06-30 Motorola, Inc. Method for using ammonium salt slurries for chemical mechanical polishing (CMP)
WO1998036045A1 (fr) * 1997-02-14 1998-08-20 Ekc Technology, Inc. Traitement post-nettoyage
GB2324750A (en) * 1997-04-28 1998-11-04 Nec Corp Automatic wafer polishing apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 1997, no. 02 28 February 1997 (1997-02-28) *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002014014A3 (fr) * 2000-08-11 2002-05-02 Rodel Inc Planarisation mechanico-chimique de substrats metalliques
US6602436B2 (en) 2000-08-11 2003-08-05 Rodel Holdings, Inc Chemical mechanical planarization of metal substrates
EP1266956A1 (fr) * 2001-06-13 2002-12-18 JSR Corporation Composition de nettoyage d'un tampon à polir et méthode de nettoyage d'un tampon à polir
US6740629B2 (en) 2001-06-13 2004-05-25 Jsr Corporation Composition for washing a polishing pad and method for washing a polishing pad
CN116988134A (zh) * 2023-07-17 2023-11-03 哈尔滨工业大学 一种搅拌摩擦增材制造成形工具清理装置及方法

Also Published As

Publication number Publication date
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