Feedback of layer thickness timing and clearance timing for polishing control

Patent metadata

Field	Value
Publication number	US-9496190-B2
Application number	US-201514665889-A
Country	US
Kind code	B2
Filing date	Mar 23, 2015
Priority date	Jan 29, 2010
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

During polishing of a first substrate at a first polishing station, a sequence of measurements by a first in-situ monitoring system is monitored to determining a first time at which the first sequence exhibits a first predefined feature indicating a predetermined thickness of an overlying layer, and during polishing of the first substrate at a second polishing station, a sequence of measurements by a second in-situ monitoring system is monitored to determine a second time indicating clearance of the overlying layer and exposure of the underlying layer. The first time is used to calculate a first adjusted polishing pressure for a second substrate at the first polishing station, and the second time is used to calculate a second adjusted polishing pressure for the second substrate at the second polishing station.

First claim

What is claimed is:

1. A method, comprising:
polishing, at a first polishing station, a first substrate having an overlying layer on an underlying layer;
during polishing of the first substrate at the first polishing station, directing a first light beam onto the overlying layer, the first light beam reflecting from the first substrate to generate a first reflected light beam;
during polishing of the first substrate at the first polishing station, generating a first sequence over time of first measurements of intensity of the first reflected light beam from the first substrate;
sorting the first measurements into groups, each group associated with a different zone of a plurality of zones on the first substrate;
for each zone determining a first time at which the first sequence over time of first measurements from the associated group exhibits a first predefined feature indicating a predetermined thickness of the overlying layer;
calculating at least one first adjusted polishing pressure for at least one zone based on a pressure applied in the at least one zone during polishing of the first substrate at the first polishing station, the first time for the at least one zone, and the first time for another zone, the first time for the at least one zone and the first time for another zone being based on the fist time for each respective zone at which the first sequence over time of first measurements of the first substrate during polishing of the first substrate exhibits the first predefined feature;
transferring the first substrate from the first polishing station to a second polishing station;
polishing a second substrate at the first polishing station using the at least one first adjusted polishing pressure;
polishing the first substrate at the second polishing station;
during polishing of the first substrate at the second polishing station, directing a second light beam onto the first substrate, the second light beam reflecting from the first substrate to generate a second reflected light beam;
during polishing of the first substrate at the second polishing station, generating a second sequence over time of second measurements of intensity of the second reflected light beam;
sorting the second measurements into groups, each group associated with a different zone of the plurality of zones on the first substrate;
for each zone determining a second time at which the second sequence over time of second measurements from the associated group exhibits a second predefined feature indicating clearance of the overlying layer and exposure of the underlying layer;
calculating at least one second adjusted polishing pressure for at least one zone based on a pressure applied in the at least one zone during polishing of the first substrate at the second polishing station, the second time for the at least one zone, and the second time for another zone, the second time for the at least one zone and the second time for another zone being based on the second time for each respective zone at which the second sequence over time of second measurements of the first substrate during polishing of the first substrate exhibits the second predefined feature; and
polishing the second substrate at the second polishing station using the at least one second adjusted polishing pressure.

2. The method of claim 1 , wherein the first light beam and the second light beam are non-polarized light.

3. The method of claim 2 , wherein the first light beam and the second light beam are laser beams.

4. The method of claim 1 , wherein the overlying layer comprises GST.

5. A method of polishing, comprising:
polishing, at a first polishing station, a first substrate having an overlying layer on an underlying layer;
during polishing of the first substrate at the first polishing station, monitoring the first substrate with a first in-situ monitoring system to generate a first sequence over time of first measurements that depend on a thickness of the overlying layer;
sorting the first measurements into groups, each group associated with a different zone of a plurality of zones on the first substrate;
for each zone, determining a first time at which the first sequence over time of first measurements from the associated group exhibits a first predefined feature indicating a predetermined thickness of the overlying layer;
calculating at least one first adjusted polishing pressure for at least one zone based on a pressure applied in the at least one zone during polishing of the first substrate at the first polishing station, the first time for the at least one zone, and the first time for another zone, the first time for the at least one zone and the first time for another zone being based on the fist time for each respective zone at which the first sequence over time of first measurements of the first substrate during polishing of the first substrate exhibits the first predefined feature;
transferring the first substrate from the first polishing station to a second polishing station;
polishing a second substrate at the first polishing station using the at least one first adjusted polishing pressure;
polishing the first substrate at the second polishing station;
during polishing of the first substrate at the second polishing station, monitoring the first substrate with a second in-situ monitoring system to generate a second sequence over time of second measurements that depend on the thickness of the overlying layer;
sorting the second measurements into groups, each group associated with a different zone of the plurality of zones on the first substrate;
for each zone, determining a second time at which the second sequence over time of second measurements from the associated group exhibits a second predefined feature indicating clearance of the overlying layer and exposure of the underlying layer;
calculating at least one second adjusted polishing pressure for at least one zone based on a pressure applied in the at least one zone during polishing of the first substrate at the second polishing station, the second time for the at least one zone, and the second time for another zone, the second time for the at least one zone and the second time for another zone being based on the second time for each respective zone at which the second sequence over time of second measurements of the first substrate during polishing of the first substrate exhibits the second predefined feature; and
polishing the second substrate at the second polishing station using the at least one second adjusted polishing pressure.

6. The method of claim 5 , wherein the plurality of zones are concentric and the at least one zone is an outermost zone of the plurality of zones.

7. The method of claim 6 , wherein the another zone is an inner zone of the plurality of zones.

8. The method of claim 5 , wherein calculating the first adjusted pressure P′ comprises calculating P′=P*(T 1 /T 2 ) wherein P is the pressure applied in the at least one zone during polishing of the first substrate at the first polishing station, T 1 is the first time for the at least one zone and T 2 is the first time for the another zone.

9. The method of claim 5 , wherein calculating the second adjusted pressure P 2 ′ comprises calculating P 2 ′=P 2 *(T 1 /T 2 ) wherein P 2 is the pressure applied in the at least one zone during polishing of the first substrate at the second polishing station, T 1 is the second time for the at least one zone and T 2 is the second time for the another zone.

10. The method of claim 5 , wherein determining the first time at which the first sequence over time of first measurements exhibits the first predefined feature indicating the predetermined thickness of the overlying laye

Assignees

• Applied Materials Inc

Inventors

• Xu Kun
• Liu Feng
• Benvegnu Dominic J
• Swedek Boguslaw A
• Wang Yuchun
• Tu Wen-Chiang
• Karuppiah Laksh

Classifications

• H10P52/402

  of semiconductor materials · CPC title

• H10P74/238 Primary

  comprising acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection or in-situ thickness measurement · CPC title

• H01L22/26 Primary

  Electricity · mapped topic

• B24B37/005

  Control means for lapping machines or devices · CPC title

• G01B11/0683

  measurement during deposition or removal of the layer · CPC title