Cmp apparatus and method for estimating film thickness
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsYU-MIN CHEN, CHIN-WEI LIANG, SHENG-CHAU CHEN, HSUN-CHUNG KUANG
Life of this patent
Estimating the term…
Abstract
A method for estimating film thickness in CMP includes the following operations. A substrate with a film formed thereon is disposed over a polishing pad with a slurry dispensed between the film and the polishing pad. A CMP operation is performed to reduce a thickness of the film. An in-situ electrochemical impedance spectroscopy (EIS) measurement is performed during the CMP operation by an EIS device to estimate the thickness of the film real-time. The CMP operation is ended when the estimated thickness of the film obtained from the fit parameters of the first equivalent electrical circuit model reaches a target thickness.
Claims20
A method for estimating film thickness in chemical-mechanical planarization (CMP), comprising:
- disposing a substrate with a film formed thereon over a polishing pad of a CMP apparatus with a slurry dispensed between the film and the polishing pad;
- performing a CMP operation to reduce a thickness of the film;
- performing an in-situ electrochemical impedance spectroscopy (EIS) measurement during the CMP operation by an EIS device, wherein the in-situ EIS measurement comprises:
- applying an alternating voltage to an electrical circuit path in the slurry and the film at different frequencies;
- collecting an impedance data of the electrical circuit path responsive to the alternating voltage at different frequencies;
- analyzing the impedance data by fitting a first equivalent electrical circuit model to the impedance data;
- estimating fit parameters of the first equivalent electrical circuit model based on a result of the analyzing the impedance data;
- and
- obtaining an estimated thickness of the film using the fit parameters of the first equivalent electrical circuit model;
- and
- ending the CMP operation when the estimated thickness of the film obtained from the fit parameters of the first equivalent electrical circuit model reaches a target thickness.
A chemical-mechanical planarization (CMP) apparatus, comprising:
- a polishing head, configured to hold a substrate with a film formed thereon;
- a platen, in opposite to the polishing head;
- a polishing pad, supported by the platen and configured to polish the film;
- a slurry delivery system, configured to supply a slurry over the polishing pad;
- an electrochemical impedance spectroscopy (EIS) device, wherein the EIS device is configured to in-situ obtain an impedance data of an electrical circuit path in the slurry and the film during a CMP operation, and configured to analyze the impedance data.
A chemical-mechanical planarization (CMP) apparatus, comprising:
- a polishing head, configured to hold a film;
- a platen, opposing the polishing head;
- a polishing pad, supported by the platen and configured to polish the film;
- and
- a probe, arranged in the platen and configured to collect an impedance data of the film, the probe comprising an end extending toward the polishing pad, wherein the end of the probe is exposed through a polishing surface of the polishing pad to contact a slurry.
Dependencies are inferred from the claim text.