US 2003/0201768 A1Published application

Eddy current measuring system for monitoring and controlling a CMP process

OwnerCuong Duy Leinventor

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Abstract

A method for estimating a thickness profile of a substrate sample that has undergone a chemical-mechanical polishing (CMP) process includes obtaining initial and terminating resistance and reactance measurements from the sample. Initial eddy current measurement values are obtained while an eddy current probe is positioned at an initial distance relative to the substrate sample, and terminating values are obtained while the eddy current probe is positioned at a modified distance relative to the sample. An intersecting line can be calculated using the initial and terminating resistance and reactance measurements. An intersecting point between a previously defined natural intercepting curve and the intersecting line may also be determined. A reactance voltage of the intersecting point may be located along a digital calibration curve to identify a closest-two of a plurality of calibration samples. The conductive top layer thickness of the substrate sample can then be determined by approximating a location, using linear or non-linear calculations, of the reactance voltage relative to the closest-two of the plurality of calibration samples.

Claims28

Dependent claims

A method for thickness estimation of a conductive top layer of a substrate sample, said method comprising:

(a) receiving said substrate sample after said substrate sample has undergone a top layer removal process removing a portion of said conductive top layer of said substrate sample;
(b) obtaining initial resistance and reactance measurements from said substrate sample using an eddy current probe positioned at an initial distance relative to said substrate sample;
(c) obtaining terminating resistance and reactance measurements from said substrate sample using said eddy current probe positioned at a modified distance relative to said substrate sample;
(d) calculating an intersecting line using said initial and terminating resistance and reactance measurements;
(e) determining an intersecting point between a previously defined natural intercepting curve and said intersecting line, wherein said natural intercepting curve is defined by a plurality of initial resistance and reactance measurements obtained from at least one calibration sample individually or collectively having a known range of top layer thicknesses;
(f) locating a reactance voltage of said intersecting point along a digital calibration curve to identify a closest-two of said known range of top layer thicknesses, wherein said digital calibration curve is defined by a plurality of initial reactance measurements and corresponding top layer thicknesses of said at least one calibration sample;
and
(g) estimating a thickness of said conductive top layer of said substrate sample by approximating a location of said reactance voltage relative to said closest-two of said known range of top layer thicknesses of said at least one calibration sample.

5 more elements

A system for thickness estimation of a conductive top layer of a substrate sample, said system comprising:

an eddy current probe comprising an eddy current sense coil;
a controller providing relative motion between said eddy current probe and said substrate sample;
a processor for processing measurements detected by said eddy current sense coil, wherein said processor is configured to estimate a thickness of said conductive top layer of said substrate sample by a method comprising:
(a) receiving said substrate sample after said substrate sample has undergone a top layer removal process removing a portion of said conductive top layer of said substrate sample;
(b) obtaining initial resistance and reactance measurements from said substrate sample using an eddy current probe positioned at an initial distance relative to said substrate sample;
(c) obtaining terminating resistance and reactance measurements from said substrate sample using said eddy current probe positioned at a modified distance relative to said substrate sample;
(d) calculating an intersecting line using said initial and terminating resistance and reactance measurements;
(e) determining an intersecting point between a previously defined natural intercepting curve and said intersecting line, wherein said natural intercepting curve is defined by a plurality of initial resistance and reactance measurements obtained from at least one calibration sample individually or collectively having a known range of top layer thicknesses;
(f) locating a reactance voltage of said intersecting point along a digital calibration curve to identify a closest-two of said known range of top layer thicknesses, wherein said digital calibration curve is defined by a plurality of initial reactance measurements and corresponding top layer thicknesses of said at least one calibration sample;
and
(g) estimating a thickness of said conductive top layer of said substrate sample by approximating a location of said reactance voltage relative to said closest-two of said known range of top layer thicknesses of said at least one calibration sample.

8 more elements

A monitoring system providing a thickness profile of a conductive top layer of a substrate sample, said system comprising:

an eddy current probe support;
a plurality of eddy current probes comprising separate eddy current sense coils, wherein said plurality of eddy current probes are configured with said eddy current probe support;
a controller configured with said eddy current probe support providing relative motion between each of said plurality of said eddy current probes and said substrate sample;
a processor for processing measurements detected by each of said plurality of eddy current sense coils, wherein said processor is configured to estimate a thickness profile of said conductive top layer of said substrate sample by a method comprising:
(a) receiving said substrate sample after said substrate sample has undergone a top layer removal process removing a portion of said conductive top layer of said substrate sample;
(b) obtaining initial resistance and reactance measurements from said substrate sample using one of said plurality of eddy current probes positioned at an initial distance relative to said substrate sample;
(c) obtaining terminating resistance and reactance measurements from said substrate sample using said one of said plurality of eddy current probes positioned at a modified distance relative to said substrate sample;
(d) calculating an intersecting line using said initial and terminating resistance and reactance measurements;
(e) determining an intersecting point between a previously defined natural intercepting curve and said intersecting line, wherein said natural intercepting curve is defined by a plurality of initial resistance and reactance measurements obtained from at least one calibration sample individually or collectively having a known range of top layer thicknesses;
(f) locating a reactance voltage of said intersecting point along a digital calibration curve to identify a closest-two of said known range of top layer thicknesses, wherein said digital calibration curve is defined by a plurality of initial reactance measurements and corresponding top layer thicknesses of said at least one calibration sample;
(g) estimating a thickness of said conductive top layer of said substrate sample by approximating a location of said reactance voltage relative to said closest-two of said known range of top layer thicknesses of said at least one calibration sample;
and
(h) estimating said thickness profile of said conductive top layer of said substrate sample by repeating operations (b) through (g) for each of said plurality of eddy current probes.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/417,042Filed 14 Apr 2003
Priority: 7 Apr 2000
Published: 30 Oct 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification2 codes

G01B 7/105
Using magnetic means, e.g. by measuring change of reluctance: for measuring thickness of coating
G01B
Measuring length, thickness or similar linear dimensions

Family

Application09/545,119Continuation in part · filed 7 Apr 2000
Application09/835,975Continuation in part · filed 17 Apr 2001
Application10/417,042Continuation in part · filed 14 Apr 2003
US 2002/0149360 A1Published application
US 6,407,546 B1Related patent
US 6,549,006 B2Related patent
US 6,741,076 B2Related patent
US 2003/0201768 A1This patent

From the US filing history. Foreign family members aren’t listed.