Abrading – Abrading process – With tool treating or forming
Reexamination Certificate
2000-03-31
2003-09-30
Hail, III, Joseph J. (Department: 3723)
Abrading
Abrading process
With tool treating or forming
C451S285000, C451S299000, C051S302000
Reexamination Certificate
active
06626743
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for conditioning a polishing pad. More particularly, the present invention relates to a method and apparatus for conditioning a polishing pad used in the chemical mechanical planarization of semiconductor wafers.
BACKGROUND
Semiconductor wafers are typically fabricated with multiple copies of a desired integrated circuit design that will later be separated and made into individual chips. A common technique for forming the circuitry on a semiconductor is photolithography. Part of the photolithography process requires that a special camera focus on the wafer to project an image of the circuit on the wafer. The ability of the camera to focus on the surface of the wafer is often adversely affected by inconsistencies or unevenness in the wafer surface. This sensitivity is accentuated with the current drive toward smaller, more highly integrated circuit designs. Semiconductor wafers are also commonly constructed in layers, where a portion of a circuit is created on a first level and conductive vias are made to connect up to the next level of the circuit. After each layer of the circuit is etched on the wafer, an oxide layer is put down allowing the vias to pass through but covering the rest of the previous circuit level. Each layer of the circuit can create or add unevenness to the wafer that is preferably smoothed out before generating the next circuit layer.
Chemical mechanical planarization (CMP) techniques are used to planarize the raw wafer and each layer of material added thereafter. Available CMP systems, commonly called wafer polishers, often use a rotating wafer holder that brings the wafer into contact with a polishing pad moving in the plane of the wafer surface to be planarized. A polishing fluid, such as a chemical polishing agent or slurry containing microabrasives, is applied to the polishing pad to polish the wafer. The wafer holder then presses the wafer against the rotating polishing pad and is rotated to polish and planarize the wafer.
With use, the polishing pads used on the wafer polishers become clogged with used slurry and debris from the polishing process. The accumulation of debris reduces the surface roughness and adversely affects polishing rate and uniformity. Polishing pads are typically conditioned to roughen the pad surface, provide microchannels for slurry transport, and remove debris or byproducts generated during the CMP process.
One present method for conditioning a polishing pad uses a rotary disk embedded with diamond particles to roughen the surface of the polishing pad. Typically, the disk is brought against the polishing pad and rotated about an axis perpendicular to the polishing pad while the polishing pad is rotated. The diamond-coated disks produce predetermined microgrooves on the surface of the polishing pad. Because the linear velocities of the leading, center and lagging portions of the disk are different, the rate of microgrooving is different. This non-uniform microgrooving has led some pad conditioner manufacturers to add a continuous oscillation motion to the rotational movement of the rotary disk pad conditioners. This extra movement can result in part of the wafer being exposed to freshly conditioned portions of the polishing pad and another part of the wafer being exposed to a used portion of the pad.
Another apparatus and method used for conditioning a pad implements a rotatable bar on the end of an arm. The bar may have diamond grit embedded in it or high pressure nozzles disposed along its length. In operation, the arm swings the bar out over the rotating polishing pad and the bar is rotated about an axis perpendicular to the polishing pad in order to score the polishing pad, or spray pressurized water on the polishing pad, in a concentric pattern. These types of pad conditioners often do not provide uniform pad conditioning because they are only applied to a small portion of the width of the pad's surface at any given time. Thus, the pressure of the conditioner against the pad can vary.
SUMMARY
According to a first aspect of the present invention, a pad conditioning apparatus is provided having a liquid distribution unit having at least one opening upon which liquid is forced through at high pressure, the opening is positioned facing the polishing pad, and a liquid recovery unit is provided for retrieving liquid and debris. The liquid recovery unit is positioned downstream from the liquid distribution unit and has at least one opening connected with a vacuum. Also a housing is provided, wherein the housing forms a liquid chamber disposed around the opening of the liquid distribution unit and a vacuum chamber disposed around the opening of the liquid recovery unit. The vacuum chamber is in communication with the liquid chamber. In one embodiment, a seal is disposed along a length of a bottom surface of the housing, wherein the seal is located between the housing and the polishing pad.
According to another aspect of the present invention, a method of conditioning a polishing pad includes the steps of applying a stream of pressurized liquid to the polishing pad, and removing a significant amount of slurry and liquid from the polishing pad using a vacuum. In one embodiment, the method further comprises removing at least a portion of the slurry from the polishing pad using a vacuum, before the applying of a stream of pressurized liquid, and running the removed slurry through a slurry reclaim system in order to remove impurities from the slurry.
REFERENCES:
patent: 3753269 (1973-08-01), Budman
patent: 3812622 (1974-05-01), Parsons
patent: 3872627 (1975-03-01), Schuster
patent: 4318250 (1982-03-01), Klievoneit et al.
patent: 4672985 (1987-06-01), Mohr
patent: 4720939 (1988-01-01), Simpson et al.
patent: 4934102 (1990-06-01), Leach et al.
patent: 5081051 (1992-01-01), Mattingly et al.
patent: 5335453 (1994-08-01), Baldy et al.
patent: 5377916 (1995-01-01), Anderson
patent: 5484323 (1996-01-01), Smith
patent: 5531635 (1996-07-01), Mogi et al.
patent: 5536202 (1996-07-01), Appel et al.
patent: 5547417 (1996-08-01), Breivogel et al.
patent: 5558568 (1996-09-01), Talieh et al.
patent: 5575707 (1996-11-01), Talieh et al.
patent: 5593344 (1997-01-01), Weldon et al.
patent: 5611943 (1997-03-01), Cadien et al.
patent: 5622526 (1997-04-01), Phillips
patent: 5643044 (1997-07-01), Lund
patent: 5655951 (1997-08-01), Meikle et al.
patent: 5692947 (1997-12-01), Talieh et al.
patent: 5692950 (1997-12-01), Rutherford et al.
patent: 5722877 (1998-03-01), Meyer et al.
patent: 5725417 (1998-03-01), Robinson
patent: 5759918 (1998-06-01), Hoshizaki et al.
patent: 5762536 (1998-06-01), Pant et al.
patent: 5779526 (1998-07-01), Gill
patent: 5871390 (1999-02-01), Pant et al.
patent: 5897426 (1999-04-01), Somekh
patent: 5899798 (1999-05-01), Trojan et al.
patent: 5908530 (1999-06-01), Hoshizaki et al.
patent: 5958794 (1999-09-01), Bruxvoort et al.
patent: 5961372 (1999-10-01), Shendon
patent: 6086460 (2000-07-01), Labunsky et al.
patent: 6244944 (2001-06-01), Elledge
patent: WO 98/45090 (1998-10-01), None
patent: WO 99/22908 (1999-05-01), None
S. Inaba, T. Katsuyama, M. Tanaka, “Study of CMP Polishing pad Control Method,” 1998 CMP-MIC Conference, Feb. 19-20, 1998, 1998 IMIC—300P/98/0444.
U.S. patent application Ser. No. 09/475,518: “Method and Apparatus for Conditioning a Polishing Pad”; Inventor: Finkelman; Filed: Dec. 30, 1999.
U.S. patent application Ser. No. 09/540,385: “Method and Apparatus for Chemically-Mechanically Polishing Semiconductor Wafers”; Inventors; Travis et al.; Filed Mar. 31, 2000.
U.S. patent application Ser. No. 09/540,810: “Fixed Abrasive Linear Polishing Belt and System”; Inventors: Zhao et al.; Filed Mar. 31, 2000.
U.S. patent application Ser. No. 09/541,144: “Method and Apparatus for Chemical Mechanical Planarization and Polishing of Semiconductor Wafers Using a Continuous Polishing Member Feed”; Inventors: Mooring et al.; Filed Mar. 31, 2000.
U.S. patent application Ser. No. Pending: A Conditioning Mechanism in a Chemical Mechanical Polishing Ap
Brinks Hofer Gilson & Lione
Hail III Joseph J.
Lam Research Corporation
Ojini Anthony
LandOfFree
Method and apparatus for conditioning a polishing pad does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for conditioning a polishing pad, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for conditioning a polishing pad will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3082106