Method and apparatus for in-line oxide thickness determination in chemical-mechanical polishing
US6020264A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1997 |
| Grant date | Feb 1, 2000 |
| Priority date | — |
| Expiry date | Jan 31, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/12
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
In-line thickness measurement of a dielectric film layer on a surface of a workpiece subsequent to a polishing on a chemical-mechanical polishing machine in a polishing slurry is disclosed. The workpiece includes a given level of back-end-of-line (BEOL) structure including junctions. The measurement apparatus includes a platen and an electrode embedded within the platen. A positioning mechanism positions the workpiece above the electrode with the dielectric layer facing in a direction of the electrode. A slurry dam is used for maintaining a prescribed level of a conductive polishing slurry above the electrode, the prescribed level to ensure a desired slurry coverage of the workpiece. A capacitance sensor senses a system capacitance C in accordance with an RC equivalent circuit model, wherein the RC equivalent circuit includes a resistance R representative of the slurry and workpiece resistances and the system capacitance C representative of the dielectric material and junction capacitances. Lastly, a capacitance-to-thickness converter converts the sensed capacitance to a dielectric thickness in accordance with a prescribed system capacitance/optical thickness calibration, wherein t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.