# US 9,437,453 B2 · Control of wafer surface charge during CMP > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,453 B2 - Document ID: US9437453B2 - Status: Granted - Kind: B2 - Application number: 14/231,533 - Filed: 2014-03-31 - Published: 2015-10-01 - Granted: 2016-09-06 - Earliest claimed: 2014-03-31 - Assignees: STMicroelectronics S.r.l. - Applicants: STMicroelectronics, Inc. - Inventors: John H. Zhang - Web page: https://patentgrep.com/patent/US9437453B2 ## CPC - H10P 52/403: {of conductive or resistive materials} - B24B 37/005: Control means for lapping machines or devices - H10P 70/277: {the processing being a planarisation of conductive layers} - H10P 72/0411: {for wet cleaning or washing} - H10P 72/0468: {comprising a chamber adapted to a particular process} - H10P 72/0472: {comprising at least one polishing chamber} - H10P 72/0604: {Process monitoring, e.g. flow or thickness monitoring} - H10P 72/3202: {Mechanical details, e.g. rollers or belts} - H10P 74/207: {Electrical properties, e.g. testing or measuring of resistance, deep levels or capacitance-voltage characteristics} - H10P 74/23: {characterised by multiple measurements, corrections, marking or sorting processes} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS ## Abstract CMP selectivity, removal rate, and uniformity are controlled both locally and globally by altering electric charge at the wafer surface. Surface charge characterization is performed by an on-board metrology module. Based on a charge profile map, the wafer can be treated in an immersion bath to impart a more positive or negative charge overall, or to neutralize the entire wafer before the CMP operation is performed. If charge hot spots are detected on the wafer, a charge pencil can be used to neutralize localized areas. One type of charge pencil bears a tapered porous polymer tip that is placed in close proximity to the wafer surface. Films present on the wafer absorb ions from, or surrender ions to, the charge pencil tip, by electrostatic forces. The charge pencil can be incorporated into a CMP system to provide an in-situ treatment prior to the planarization step or the slurry removal step. ## Claims ### Claim 1 A method, comprising: receiving a first set of surface charge data and local surface charge for a surface of a semiconductor wafer; evaluating the first set of surface charge data to determine whether or not a global charge treatment is needed; based on the first set of surface charge data, applying a global charge treatment to the entire wafer; evaluating local surface charge data at a plurality of specific local regions on the wafer to determine whether or not a local charge treatment is needed at the specific local regions; based on the local surface charge data, applying a local charge treatment to substantially neutralize the specific local regions of the surface of the semiconductor wafer; and performing a chemical-mechanical planarization (CMP) process. ### Claim 2 (depends on 1) The method of claim 1, further comprising receiving a second set of surface charge data for the surface of the semiconductor wafer; evaluating the second set of surface charge data to determine whether or not the entire wafer needs a charge neutralization procedure; based on the second set of surface charge data, applying a charge neutralization treatment to the entire wafer; and performing a post-CMP wafer cleaning procedure. ### Claim 3 (depends on 2) The method of claim 2 wherein one or both of the global charge treatment and the charge neutralization treatment further comprises immersing the wafer in an ionic solution. ### Claim 4 (depends on 1) The method of claim 1 wherein applying a local charge treatment includes electrically biasing a charge pencil tip; and removing surface charge from a localized area of the surface of the semiconductor wafer by placing the tip in close proximity to the localized area. ### Claim 5 (depends on 1) The method of claim 1 wherein applying a local charge treatment includes applying an ionic solution to a charge pencil tip; and removing surface charge from a localized area of the wafer by placing the tip in close proximity to the localized area. ### Claim 6 (depends on 5) The method of claim 5, further comprising electrically biasing the charge pencil tip. ### Claim 7 (depends on 1) The method of claim 1 wherein applying a local charge treatment further comprises removing charge of a known polarization from the surface of the wafer using a charge pencil that carries an oppositely polarized electrostatic charge to form a substantially neutralized region on the surface of the semiconductor wafer. ### Claim 8 (depends on 1) The method of claim 1 wherein applying a local charge treatment further comprises depositing charge of a known polarization onto the surface of the wafer using a charge pencil, the deposited charge together with the surface charge forming a substantially neutralized cluster. ### Claim 9 (depends on 8) The method of claim 8, further comprising removing the substantially neutralized cluster from the wafer via a wet cleaning process. ### Claim 10 A method, comprising: receiving from a metrology module within a wafer processing system, polarity and location data associated with surface charge accumulated on a surface of a semiconductor wafer; charging a tip of a charge pencil to have a net charge of opposite polarity to that of the surface charge on the wafer; positioning, via a precision motorized assembly, the tip of the charge pencil in close proximity to the surface at a location of the surface charge; and altering the surface charge on the wafer via an electrostatic force associated with the charge of opposite polarity at the tip of the charge pencil. ### Claim 11 (depends on 10) The method of claim 10 wherein altering the surface charge on the wafer further includes removing the surface charge from the wafer by attracting the surface charge to the tip, and retracting the tip away from the surface. ### Claim 12 (depends on 10) The method of claim 10 wherein altering the surface charge on the wafer further includes neutralizing the surface charge by releasing charge of opposite polarity from the tip by applying a voltage thereto. ### Claim 13 (depends on 10) The method of claim 10 wherein charging the tip of the charge pencil includes gathering ions onto the tip by absorption of an ionic solution.