Apparatus and method to determine the coefficient of friction of a chemical mechanical polishing pad during a pad conditioning process and to use it to control the process
US5743784A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1995 |
| Grant date | Apr 28, 1998 |
| Priority date | — |
| Expiry date | Dec 19, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB24B49/02
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
An apparatus and method for detecting the roughness of a CMP pad surface, in situ, during pad conditioning by measuring and making use of surface friction effects. The effect is advantageously exploited to determine an endpoint for the pad conditioning process i.e. when the surface roughness of the pad is within a desired range, to facilitate the qualification of conditioning process parameter changes by determining their effect on the conditioning process, and to optimize these parameters. Also, the effect is employed to measure non-uniformities in the pad's surface roughness, and to guide corrective measures. Generally, these objectives are accomplished using an apparatus which includes a floating head having its bottom surface in contact with the top surface of a rotating CMP pad undergoing a CMP pad conditioning process. A bracket is employed to restrain the floating head so as to prevent the head from moving along with the rotating CMP pad. A force sensing device is used to sense a restraining force exerted by the bracket on the floating head and to output a signal indicative of the restraining force. This restraining force is indicative of the friction between the floating he…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.