WO2003018256A1 - Procede et appareil d'optimalisation de fin de polissage par planarisation chimico-mecanique - Google Patents

Procede et appareil d'optimalisation de fin de polissage par planarisation chimico-mecanique Download PDF

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Publication number
WO2003018256A1
WO2003018256A1 PCT/IB2002/003443 IB0203443W WO03018256A1 WO 2003018256 A1 WO2003018256 A1 WO 2003018256A1 IB 0203443 W IB0203443 W IB 0203443W WO 03018256 A1 WO03018256 A1 WO 03018256A1
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WO
WIPO (PCT)
Prior art keywords
wafer
polishing pad
slurry
pad
polishing
Prior art date
Application number
PCT/IB2002/003443
Other languages
English (en)
Inventor
Andrew J. Black
Original Assignee
Koninklijke Philips Electronics N.V.
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 Koninklijke Philips Electronics N.V. filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2003018256A1 publication Critical patent/WO2003018256A1/fr

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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
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
    • 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
    • B24B57/00—Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents
    • B24B57/02—Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents

Definitions

  • the present invention pertains to semiconductor fabrication processing. More particularly, the present invention relates to a system and method for end-of-polish optimization for semiconductor processing.
  • STI and interlayer-dielectric (ILD) process recipes contain various steps accomplishing different objectives.
  • End-of-polish conditions are extremely important to the final number of defects on the surface of the wafer after chemical mechanical planarization (CMP).
  • CMP chemical mechanical planarization
  • Three conditions are theoretically necessary to leave behind slurry residues, pits, and scratches on the wafer surfaces after STI and LLD CMP.
  • colloidal particles present near the wafer surface. These particles are the source of residual particles on the wafer surface, they are the same particles that can agglomerate and cause microscratches and oxide pit defects.
  • Second, physical force i.e.
  • the final defectivity of the wafer determining the yield of the semiconductor fabrication process as is generally known to experts in the field of semiconductor fabrication. What is needed is a method for reducing the number of defects during an end- of-polish process that removes the colloidal particles from the wafer environment that reduces the risk of breaching the energy barrier between a particle and the surface of the wafer by optimizing pH and downforce during the end-of-polish processing.
  • the present invention is directed towards a system and method of reducing defects on a semiconductor wafer by polishing the semiconductor wafer while in contact with a high pH slurry, rinsing the slurry from said polishing pad and the surface of the wafer with a high pH solution sprayed on the polishing pad at high pressure and then spraying the polishing pad with deionized water to further clean the wafer. Additionally, it is preferred that the semiconductor wafer is biased against the polishing pad at low downforce while being rinsed with the high pH solution.
  • Figure 1 is a block diagram of a CMP machine.
  • Figure 2 is a side partial perspective view of a semiconductor wafer.
  • Figures 3 - 4 show a partial side perspective view of a currently used CMP machine during an end-of-polish cycle.
  • Figures 5 - 6 show a partial side perspective view of a CMP machine during an end-of-polish cycle in accordance with the present inventions.
  • FIG. 7 is a flow diagram of the process for one particular preferred embodiment of a CMP polish cycle for reducing defects in accordance with the present inventions.
  • FIG. 1 there is shown a block diagram of a CMP machine 100 and a side partial perspective view of a wafer 105 ( Figure 2).
  • the CMP machine 100 is fed wafers to be polished by an arm 101 and places them onto a rotating polishing pad 102.
  • the polishing pad 102 is made of a resilient material and is textured, often with a plurality of predetermined grooves, to aid the polishing process.
  • a conditioning arm 103 conditions the polishing pad.
  • a wafer is held in place on the polishing pad 102 by the arm 101.
  • the CMP machine 100 also includes a slurry dispense tube 107, extending across the radius of the polishing pad 102.
  • the slurry dispense tube 107 dispenses a flow of slurry 106 onto the polishing pad 102 from the slurry source 112.
  • the slurry 106 is a mixture of deionized water and polishing agents designed to aid chemically the smooth and predictable planarization of the wafer.
  • the pH of the slurry is very high, typically having a pH of around 10 or 11. Additionally, during polishing a high downforce of between 4 - 5 psi is applied to the wafer by the wafer arm 101.
  • the polishing action of the slurry is comprised of an abrasive frictional component and a chemical component. The abrasive frictional component is due to the f iction between the surface of the polishing pad, the surface of the wafer, and abrasive particles suspended in the slurry.
  • the chemical component is due to the presence in the slurry of polishing agents which chemically interact with the material of the dielectric or metal layer of the wafer.
  • the chemical component of the slurry is used to soften the surface of the dielectric layer to be polished, while the frictional component removes material from the surface of the wafer.
  • deionized water is dispensed from the deiomzed water source 110 via the high-pressure spray nozzle 108 onto the pad.
  • High pressure spray nozzle 108 may be of the type disclosed in commonly assigned U. S. Patent Application Serial No. 09/871,507.
  • the high pH slurry is mixed with deionized water rinse, which contributes to the destructive mechanisms. Additionally, slurry abrasive particles and agglomerations of abrasive particles, such as particles 106, are stuck to the surface of wafer 105 and are additionally stuck in the grooves 114 and in the fibers of the polishing pad 102.
  • the pad is cleaned with high pressure deiomzed water spray 130 via the high-pressure spray nozzle. The wafer 105 floats on the deionized water during the pad cleaning step.
  • the wafer 105 is cleaned as part of the end-of- polish process.
  • FIG 4 in connection with the pad cleaning step shown in Figure 3, current end-of-polish processes clean the wafer by applying a downforce with the carrier ring to the wafer onto the clean pad and continuing the high pressure deiomzed water spray 130, via the high pressure spray nozzle 108.
  • a number of abrasive particles 106 remain stuck to the wafer and in the grooves 114 of the pad 102.
  • these particles can cause wafer defects during the end - of -polish process while force is applied to the wafer in the presence of these abrasive particles in the low pH environment.
  • Figures 5 - 7 there is shown a CMP system and method for optimizing the end - of- polish process which reduces the conditions that allow for defects to be generated on the semiconductor wafer surface.
  • zeta potential an electrically charged thin layer when suspended in a liquid solution.
  • This charge is known as the zeta potential and can be either negative or positive.
  • the zeta potential appears at the outer surface of the particle such that a small charge field surrounds the particle.
  • Silica particles in a basic aqueous solution having a pH of about 10 or more results in a negative zeta potential on the silica particles.
  • the zeta potential of any other particles present, as well as that of the surfaces contacted by the solution is negative at such a high pH.
  • the silica particles are thus electrostatically repelled from the semiconductor wafer facilitating the removal of the slurry residue from the wafer surface.
  • the high pH solution at the surface prevents the silica particles from overcoming the electrical repulsion at the surface and reduces the Van der Waals attraction.
  • the pH at the surface of the wafer is lowered in the presence of silica particles, colloids form and silica agglomeration occurs on the surface of the wafer.
  • any time the pH of the wafer surface is lowered a higher defectivity environment exists in the presence of microscopic particles.
  • high downforce applied to the wafer can contribute to the abrasive particles overcoming the energy barrier between a colloid and the wafer surface, thus contributing to wafer defects. Defects generated include scratches on the wafer by slurry abrasive agglomerates and slurry abrasive (or any other particle) attaching to the wafer surface.
  • the wafer is polished on the platen using a high pH slurry and a high downforce.
  • Step 310 the slurry is cleaned from the pad and wafer using a high pressure spray of a high pH solution, while the wafer is biased against the pad with a low downforce.
  • Step 320 the system of the present embodiment includes a polishing pad 202 having grooves 214 thereon. Abrasive particles 206 are similarly adhered to the wafer surface and in the grooves 214 of the polishing pad 202.
  • Wafer carrier arm 201 holds the surface of the semiconductor wafer 205 against the polishing pad 202.
  • the carrier ring 216 applies a low downforce to the wafer 205.preferrably the downforce on the wafer 205 is from 1 - 3 psi. More preferably, the downforce on the wafer 205 during the pad and wafer cleaning step is around 2 psi.
  • the pad and wafer are rinsed with a high pH solution 225 from the pH adjusted solution source 212.
  • the pad is rinsed by spraying the high pH solution 225 from the high pressure spray nozzle 208.
  • High pressure spray nozzle 208 directs the high pH solution 225 towards the pad 202 with a pressure of between 10 and 20 psi. More preferably, the pressure of the high pH solution spray is between 14 and 18 psi.
  • the high pH solution is directed into the spray nozzle by the valve 220.
  • the high pH solution may be a solution such as dilute ammonia or NH 4 OH and is preferably chosen to have a pH that approximates that of the slurry base and preferably has a pH of between 10 and 12.
  • the pH at the wafer 205 and pad 202 during the rinsing step is kept constantly high, maintaining the high electrostatic repulsion between the semiconductor wafer and the abrasive particles.
  • the majority of abrasive particles are rinsed from the pad and wafer, aided by the electrostatic repulsion of the high pH chemistry.
  • valve 220 is not meant to be limiting, as other methods of providing a high pH solution to the high pressure spray nozzle 208 may be used.
  • tank 212 could hold a concentrated high pH solution, and liquids from tank 210 and 212 can be mixed during use, when a high pH solution is desired at the polishing pad.
  • the pad and wafer are rinsed with deionized water.
  • the deionized water may be high pressure deionized water spray 230 from the high pressure spray nozzle 208, however, this is not meant to be limiting as low pressure deiomzed water may also be used.
  • Step 330 of Figure 7. If desired, the low downforce is maintained on the wafer 206 by the carrier film 216 of the wafer arm 201.
  • the present inventions reduce defects on the semiconductor wafer during the end - of- polish process by maintaining the net energy barrier between the defect causing abrasive and the semiconductor surface at a high level until the high pressure spray has a chance to clean the pad of the abrasive. Only after the abrasive has been removed from the pad is the pH of the wafer lowered.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

Abstract

L'invention concerne un système et un procédé faisant appel à un rinçage haute pression à pH élevé destiné à enlever les particules de bouillie situées à la surface et à l'intérieur d'un feutre de polissage (202). Tandis que le jet haute pression retire la bouille du feutre, une faible force descendante est appliquée sur la plaquette (205). Dès que la bouillie a été enlevée du feutre, la plaquette en semi-conducteur est rincée avec de l'eau désionisée pour que le pH à la surface de la plaquette soit à nouveau neutre.
PCT/IB2002/003443 2001-08-31 2002-08-21 Procede et appareil d'optimalisation de fin de polissage par planarisation chimico-mecanique WO2003018256A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US94446901A 2001-08-31 2001-08-31
US09/944,469 2001-08-31

Publications (1)

Publication Number Publication Date
WO2003018256A1 true WO2003018256A1 (fr) 2003-03-06

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TW (1) TW569333B (fr)
WO (1) WO2003018256A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2013401144B2 (en) * 2013-12-02 2016-04-21 Qingdao Technological University Controllable nanoparticle jet flow transportation type minimal quantity lubrication grinding equipment under magnetically enhanced electric field
CN109664162A (zh) * 2017-10-17 2019-04-23 长鑫存储技术有限公司 在金属栓塞的化学机械研磨中的制程动态优化方法及系统

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1038635A2 (fr) * 1999-03-16 2000-09-27 Applied Materials, Inc. Dispositif de polissage
US6220934B1 (en) * 1998-07-23 2001-04-24 Micron Technology, Inc. Method for controlling pH during planarization and cleaning of microelectronic substrates
US20010001756A1 (en) * 1998-04-24 2001-05-24 Applied Materials, Inc. A Delaware Corporation Chemical mechanical polishing with multiple polishing pads

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010001756A1 (en) * 1998-04-24 2001-05-24 Applied Materials, Inc. A Delaware Corporation Chemical mechanical polishing with multiple polishing pads
US6220934B1 (en) * 1998-07-23 2001-04-24 Micron Technology, Inc. Method for controlling pH during planarization and cleaning of microelectronic substrates
EP1038635A2 (fr) * 1999-03-16 2000-09-27 Applied Materials, Inc. Dispositif de polissage

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2013401144B2 (en) * 2013-12-02 2016-04-21 Qingdao Technological University Controllable nanoparticle jet flow transportation type minimal quantity lubrication grinding equipment under magnetically enhanced electric field
CN109664162A (zh) * 2017-10-17 2019-04-23 长鑫存储技术有限公司 在金属栓塞的化学机械研磨中的制程动态优化方法及系统
CN109664162B (zh) * 2017-10-17 2020-02-07 长鑫存储技术有限公司 在金属栓塞的化学机械研磨中的制程动态优化方法及系统

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Publication number Publication date
TW569333B (en) 2004-01-01

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