US 6,553,332 B2 · Method for evaluating process chambers used for semiconductor manufacturing

Abstract

A process chamber (12) is used for plasma etching of a wafer (21) disposed therein. A gas mixture supplied to the chamber eventually passes through openings (28) in a baffle plate (27). After the chamber has been cleaned, several test wafers are etched under conditions which are equivalent, except that a different gas pressure is used for each wafer. The effective etch rates are measured from these wafers, and used to extrapolate a reference curve (141) representing effective etch rate relative to pressure. During subsequent production use of the chamber, a similar procedure is periodically used to generate a test curve (142). The peak values (143, 144) of the reference and test curves are compared (147) to monitor process drift within the chamber. The peak values of respective curves obtained from two or more similar chambers can be compared to evaluate performance differences between the chambers.

Claims13

Dependent claims

A method for monitoring process drift in a process chamber, comprising the steps of:

successively introducing a plurality of test wafers into said process chamber, and etching each said test wafer under a respective set of chamber conditions, said sets of chamber conditions being substantially the same except that each involves use of a respective different gas pressure within said chamber;
determining for each said test wafer an effective test etch rate thereof;
extrapolating from said test etch rates and respective said corresponding gas pressures a test curve representing variation of test etch rate relative to gas pressure;
and
comparing said test curve to a reference curve in order to determine a relative pressure offset therebetween, said pressure offset being representative of a degree of process drift occurring within said chamber.

2 more elements

A method for matching etch performance in first and second process chambers, comprising the steps of:

successively introducing a plurality of first test wafers into said first process chamber, and etching each said first test wafer under a respective set of chamber conditions, said sets of chamber conditions for said first process chamber being substantially the same except that each involves use of a respective different gas pressure;
successively introducing a plurality of second test wafers into said second process chamber, and etching each said second test wafer under a respective set of chamber conditions, said sets of chamber conditions for said second process chamber being substantially the same except that each involves use of a respective different gas pressure;
determining for each of said first and second test wafers an effective test etch rate thereof;
extrapolating from said test etch rates and respective said corresponding gas pressures for said first test wafers a first test curve representing variation of test etch rate relative to gas pressure for said first chamber;
extrapolating from said test etch rates and respective said corresponding gas pressures for said second test wafers a second test curve representing variation of test etch rate relative to gas pressure for said second chamber;
and
comparing said first test curve to said second test curve in order to determine a relative offset therebetween which represents an operational difference between said first and second chambers.

4 more elements

Dependencies are inferred from the claim text.

Method for evaluating process chambers used for semiconductor manufacturing

Life of this patent

Method for evaluating process chambers used for semiconductor manufacturing

Life of this patent

Abstract

Claims13