EP1380048A1 - Procede et composition de polissage par cmp - Google Patents

Procede et composition de polissage par cmp

Info

Publication number
EP1380048A1
EP1380048A1 EP01916557A EP01916557A EP1380048A1 EP 1380048 A1 EP1380048 A1 EP 1380048A1 EP 01916557 A EP01916557 A EP 01916557A EP 01916557 A EP01916557 A EP 01916557A EP 1380048 A1 EP1380048 A1 EP 1380048A1
Authority
EP
European Patent Office
Prior art keywords
polishing
copper
polishing composition
high points
ions
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.)
Withdrawn
Application number
EP01916557A
Other languages
German (de)
English (en)
Inventor
Terence M. Thomas
Qianquiu Ye
Joseph K. So
Wendy B. Goldberg
Wade Godfrey
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.)
DuPont Electronic Materials Holding Inc
Original Assignee
Rodel Inc
Rodel Holdings Inc
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 Rodel Inc, Rodel Holdings Inc filed Critical Rodel Inc
Publication of EP1380048A1 publication Critical patent/EP1380048A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F3/00—Brightening metals by chemical means
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
    • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
    • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
    • H10P52/40—Chemomechanical polishing [CMP]
    • H10P52/403—Chemomechanical polishing [CMP] of conductive or resistive materials

Definitions

  • the invention pertains to polishing methods and slurry formulations used in the planarizafion of integrated circuit surfaces containing various films, most particularly those of a metal, a barrier or liner layer, and a dielectric layer on a semiconductor wafer.
  • U.S. Pat. No. 5,676,587 discloses a two-step polishing process to be used with Cu interconnect structures. The first step is performed to remove most of the overburden of Cu, and the second step is performed to remove the barrier or liner layer of Ta, TaN, Ti, or TiN. For the second step, a silica based slurry of near-neutral pH is disclosed.
  • One of the problems resulting from polishing a semiconductor wafer by CMP is that the copper interconnect structures, providing electrical circuit interconnects, have a surface roughness that exceeds acceptable limits as specified by manufacturing standards. It has been recognized that an excessive surface roughness occurs from the rigors of CMP polishing. A need has existed for a process of polishing a semiconductor wafer that smoothes the surface roughness to acceptable limits. Further, a need has existed for a polishing composition for polishing a semiconductor wafer with interconnects having a surface roughness within acceptable limits.
  • the invention includes a method for polishing a semiconductor wafer, includes the steps of: providing a fluid polishing composition with chloride ions, polishing a barrier layer on the semiconductor wafer with the fluid polishing composition to remove the barrier layer and to polish high points on copper interconnects and solublize copper ions in the polishing composition, and replating the copper ions from solution in the fluid polishing composition to smooth the surface of the copper interconnects, while the chloride ions migrate near the high points to deter replating of copper ions onto the high points. By deterring such copper replating from the high points, the surface of the copper interconnects become smoothed to have a surface roughness within acceptable limits as specified by manufacturing standards.
  • the invention includes a polishing composition for polishing a semiconductor wafer includes a source of chloride ions in solution that migrate to high points on copper interconnects that are below a polished surface of the semiconductor wafer to deter replating of copper ions from solution onto the high points.
  • a semiconductor wafer is constructed of three different films or layers: a conductive metal layer, a barrier or liner layer between the conductive metal layer and a dielectric layer, and the dielectric layer.
  • a semiconductor wafer is constructed with, a conductive copper layer, a barrier layer of tantalum or tantalum nitride, and a dielectric layer of silicon dioxide. Polishing by performing CMP removes the Cu and Ta/TaN barrier layer as fast as possible, while removing the SiO 2 dielectric layer as slow as possible. Further, It is critical to retain conductive circuit interconnects recessed below the surface being polished. Removal of Cu within the interconnect structure is undesirable, and is known as “dishing”. Removal of the SiO 2 dielectric layer within the interconnect structure is undesirable, and is known as "erosion”.
  • chloride ions will bond to a semiconductor surface, and is present as a mobile species able to rapidly move over the surface. These mobile species will equilibrate to specific sites to minimize the energy of the system. These same localized high surface energy sites are the sites where defects initiate. The presence of the chloride ions at these sites decreases the surface energy at these sites to make them essentially indistinguishable from the surface energy at any other site. The uniform surface energy negates localized non-uniform processes and variations in the surface condition of the wafer. Since this is a surface phenomenon, the amount of a compound providing chloride ions necessary to cause this negation of localized variations may be as low as 5 ppm. Preferably the amount of compound used is between 7 and 2000 ppm. Most preferably between 10 and 1000 ppm.
  • compositions useful in polishing copper typically comprise a complexing agent providing copper ions in solution in the composition, such as citric acid; an inhibitor of initial corrosion, such as benzotriazole; and an organic polymer, such as polyvinyl pyrrolidone.
  • the composition includes an abrasive in the form of colloidal silica particles in fluid suspension, to be used with a polishing pad that is without abrasives.
  • the abrasive is absent from the composition, such that the composition is abrasive free to be used with a polishing pad that itself has abrasives.
  • compositions A and B were made comprising colloidal silica, citric acid, BTA (benzotriazole), and PVP (polyvinyl pyrrolidone). Further, composition B was made to include 5 to 10000 ppm, parts per million of ammonium chloride and 0.01% of ammonium perchlorate, all being in weight per cent. Patterned wafers comprising copper interconnects were polished on an IPEC Westech 372 polisher under standard conditions using compositions A and B. Surface roughness was measured using an AFM (Atomic Force Microscope) available from Digital Instruments, Inc.
  • AFM Anamic Force Microscope
  • the table discloses the improvement in roughness when a small amount of chloride ions are added to a polishing composition.
  • Such chloride ions are present in a polishing composition to improve surface roughness of the copper interconnects as a result of first step polishing and/or second step polishing.
  • first step polishing is performed, with a polishing pad and a polishing composition, according to a known CMP process to remove excess copper metal from an underlying barrier layer, while leaving patterned copper in a pattern of trenches below the polished surface of the barrier layer.
  • the patterned copper provides the electrical circuit interconnects in the trenches.
  • first step polishing tends to leave the patterned copper with a surface roughness that exceeds allowable limits that are specified by manufacturing standards.
  • Surface roughness can be considered as having high points on the surface of the patterned copper. Some of the high points can be quite sharp. Others are less sharp, but nonetheless, exceed the allowable limits for surface roughness.
  • the surface roughness could have been avoided by providing chloride ions in the polishing composition that accompanies first step polishing.
  • excessive surface roughness that results from first step polishing is reduced in roughness by performing second step polishing with a polishing composition containing chloride ions.
  • Such high points can be considered as being high energy areas, as in a situation wherein the patterned copper is wetted by the polishing composition and carries an electrical charge, resulting in an electrical field concentrating at the high points.
  • second step polishing is performed by a known CMP process to remove the barrier layer from an underlying dielectric layer, and to leave the copper interconnects in the trenches that are recessed below a polished surface of the dielectric layer.
  • chloride ions provided in a fluid polishing composition, reduces surface roughness of the copper interconnects, such that the surface roughness is within the allowable limits.
  • Second step polishing by a known CMP process is performed with a fluid polishing composition that, either has an oxidizer that is selective to removal of the material forming the barrier layer and selective to removal of copper, or that is without an oxidizer that is selective to removal of copper while being selective to removal of the barrier layer.
  • Second step polishing is performed to remove the barrier layer by polishing action, and to a lesser extent, to remove high points of copper by the polishing action and provide copper ions that solublize, in solution with the fluid polishing composition.
  • chloride ions are provided in the fluid polishing composition.
  • the chloride ions tend to migrate to the high energy areas, and tend to null the electrical field and prevent replating of copper ions, and the formation of nodules and/or dendrites, on the high energy areas.
  • the chloride ions replate evenly over the surface of the interconnects, which reduces the surface roughness to within acceptable limits.
  • polishing During polishing, migration of the chloride ions to the high points, nulls the electrical field concentrated at the high energy areas, which deters the attraction of copper ions for replating from solution onto the high points on the patterned copper. Copper ions replate from solution in a distributed manner on the copper surface, and less preferably accumulate on the high points. Further, polishing with or without an oxidizer in the polishing composition, polishes the high points, and removes copper therefrom.
  • polishing the high points serves to remove the high energy areas, such that copper ions replate from solution in a distributed manner, which contributes to smoothing the surface roughness to be within acceptable limits.
  • Second step polishing removes oxidized copper from the high points, and, as known in the field of CMP polishing, removed oxide ions tend to remain in solution with the fluid polishing composition.
  • the oxidizer contributes to removal of high points on the copper surface, which contributes to smoothing the surface roughness to be within acceptable limits.
  • a balance is struck by the concentration of the oxidizer and the concentration of chloride ions, such that chloride ions are present in a concentration sufficient to be near to each of the high energy areas, and deter the attraction of copper ions for replating from solution onto the high energy areas.
  • the chloride ions in the polishing composition are mobile species of ions.
  • the high energy areas are substantially eliminated, and the chloride ions in the polishing composition are mobile and free of attraction to high energy areas.
  • the mobile chloride ions are readily displaced by agitation away from the polished surface, which allows polishing to operate without interference by the chloride ions.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)

Abstract

L'invention concerne une composition de polissage d'une tranche de semi-conducteur. Cette composition renferme une source d'ions chlorure dans une solution qui réduit la rugosité des surfaces des interconnexions de cuivre encastrées dans la tranche. Les points élevés des interconnexions de cuivre sont polis au cours d'une opération de polissage. Les ions chlorure migrent vers les champs électriques concentrés autour des points élevés. Les ions chlorure au niveau des points élevés empêche le replacage des ions de cuivre de la solution sur les points élevés. Les ions de cuivre subissent un replacage uniforme sur la surface des interconnexions, ce qui permet de réduire la rugosité de cette même surface.
EP01916557A 2001-03-12 2001-03-12 Procede et composition de polissage par cmp Withdrawn EP1380048A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2001/007734 WO2002073681A1 (fr) 2001-03-12 2001-03-12 Procede et composition de polissage par cmp

Publications (1)

Publication Number Publication Date
EP1380048A1 true EP1380048A1 (fr) 2004-01-14

Family

ID=21742391

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01916557A Withdrawn EP1380048A1 (fr) 2001-03-12 2001-03-12 Procede et composition de polissage par cmp

Country Status (4)

Country Link
EP (1) EP1380048A1 (fr)
JP (1) JP2004523123A (fr)
KR (1) KR100762424B1 (fr)
WO (1) WO2002073681A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6916742B2 (en) * 2003-02-27 2005-07-12 Rohm And Haas Electronic Materials Cmp Holdings, Inc. Modular barrier removal polishing slurry
US8728934B2 (en) 2011-06-24 2014-05-20 Tessera, Inc. Systems and methods for producing flat surfaces in interconnect structures

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
PL137972B1 (en) * 1983-05-19 1986-08-30 Akad Gorniczo Hutnicza Agent for polishing copper and its alloys
US6063306A (en) * 1998-06-26 2000-05-16 Cabot Corporation Chemical mechanical polishing slurry useful for copper/tantalum substrate
US6083840A (en) * 1998-11-25 2000-07-04 Arch Specialty Chemicals, Inc. Slurry compositions and method for the chemical-mechanical polishing of copper and copper alloys
TW501197B (en) * 1999-08-17 2002-09-01 Hitachi Chemical Co Ltd Polishing compound for chemical mechanical polishing and method for polishing substrate

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO02073681A1 *

Also Published As

Publication number Publication date
WO2002073681A1 (fr) 2002-09-19
KR20030082969A (ko) 2003-10-23
KR100762424B1 (ko) 2007-10-02
JP2004523123A (ja) 2004-07-29

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