Substrate state detection for plasma processing tools
A substrate processing tool capable of detecting a gap and/or shifting of a substrate clamped to a clamping surface in a processing chamber based on observed behavior of RF power delivered to the processing chamber during processing. The behavior of the RF power is observed by comparing a voltage-current phase angle difference and/or impedance magnitude change between a real RF power component and a reactive RF power component of the RF power delivered to the processing chamber.
1 . A substrate processing tool, comprising
a processing chamber;
a substrate pedestal having a surface for supporting a substrate within the processing chamber;
a Radio Frequency (RF) electrode configured to deliver RF power within the processing chamber, the RF power inducing a plasma in the processing chamber when the substrate is being processed;
and
a substrate state detection system including a probe capable of measuring RF characteristics that indicate a state of the substrate during processing by measuring a delivered RF power within the processing chamber, the state comprising any of bowing of the substrate, gaps between the substrate and the surface or shifting of the substrate relative to the surface, and the substrate state detection system further including a controller configured to receive one or more data samples derived from the delivered RF power measured by the probe, set a data flag indicting that the substrate as having a gapping, bowing and/or shifting issue if the one or more data samples derived from the measured delivered RF power exceed an upper dynamic comfort threshold or a lower dynamic comfort threshold, and in response to the data flag being set, perform a recovery process operation for the substrate, wherein the upper dynamic comfort threshold and the lower dynamic comfort threshold both shift over time to follow an RF power curve during at least a portion of a processing run in which the substrate is being processed in the processing chamber, and wherein the RF power curve, the upper dynamic comfort threshold, and the lower dynamic comfort threshold are derived from empirical data samples of measured delivered RF power collected during processing runs of substrates that do not have gapping, bowing, or shifting issues.
2 . The substrate processing tool of claim 1 , wherein:
the RF electrode is arranged to provide constant RF power to the processing chamber; and
the substrate state detection system is further arranged to:
measure real RF power and reactive RF power in the processing chamber; and
ascertain the state of the substrate based on changes in the reactive RF power within the processing chamber.
3 . The substrate processing tool of claim 2 , wherein the substrate state detection system is further configured to compare a voltage-current phase angle difference of the RF power.
4 . The substrate processing tool of claim 3 , wherein the voltage-current phase angle increases or decreases as a degree of any bowing, gaping or shifting of the substrate increases or decreases respectively.
5 . The substrate processing tool of claim 2 , wherein the substrate state detection system is further configured to compare a change in an impedance magnitude of the reactive RF power.
6 . The substrate processing tool of claim 5 , wherein the change in the impedance magnitude becomes larger or smaller as the degree of the gapping, bowing or shifting become larger or smaller respectively.
7 . The substrate processing tool of claim 1 , wherein the controller is configured to:
generate the RF power curve from the empirical data samples of measured delivered RF power collected during the processing runs of substrates that do not have gapping, bowing, or shifting issues; and
derive the upper dynamic comfort threshold and the lower dynamic comfort threshold from the generated RF power curve.
8 . The substrate processing tool of claim 1 , wherein the probe includes a voltage/current meter capable of measuring:
(a) voltage;
(b) current; and
(c) a phase angle between the voltage and the current.
9 . The substrate processing tool of claim 8 , wherein the voltage/current meter is electrically coupled in series between an RF source and the RF electrode.
10 . The substrate processing tool of claim 2 , wherein the changes in the measured reactive RF power are indicative of changes in capacitance between the substrate and the surface of the substrate pedestal, wherein the capacitance:
decreases as the magnitude of the gap increases; and
increases as the magnitude of the gap decreases.
11 . The substrate processing tool of claim 2 , wherein the changes in the measured reactive RF power are indicative of changes in capacitance between the substrate and the surface of the substrate pedestal, wherein the capacitance:
decreases as the degree of the shifting of the substrate increases; and
increases as the degree of the shifting of the substrate decreases.
12 . The substrate processing tool of claim 1 , wherein the RF electrode is positioned on or within the substrate pedestal.
13 . The substrate processing tool of claim 1 , wherein the surface of the substrate pedestal for supporting the substrate is further configured to clamp the substrate to the surface.
14 . The substrate processing tool of claim 1 , wherein the recovery process operation includes at least one of:
(a) increasing a clamping force for clamping the substrate to the surface of the substrate pedestal;
(b) pausing the processing of the substrate; or
(c) adjusting one or more processing parameters of a process used when processing the substrate.
15 . The substrate processing tool of claim 1 , wherein the substrate processing tool is one of the following Plasma Enhanced Chemical Vapor Deposition (PECVD) tool, a Low Pressure (LPCVD), Ultra High Vacuum (UHVCVD), Atomic Layer Deposition (ALD), Plasma-Enhanced Atomic Layer Deposition (PEALD) or a plasma etching tool.
16 . A substrate processing tool including a probe capable of measuring RF characteristics indicating observed behavior of RF power delivered to a processing chamber of the substrate processing tool, and a controller configured to receive one or more data samples derived from the RF characteristics measured by the probe, detect a gap and/or shifting of a substrate positioned on a support surface in the processing chamber based on the observed behavior of the RF power delivered to the processing chamber as indicated by the one or more data samples derived from the RF characteristics measured by the probe exceeding an upper dynamic comfort threshold or a lower dynamic comfort threshold, and in response to detecting the gap and/or shifting of the substrate, perform a recovery process operation for the substrate, wherein the upper dynamic comfort threshold and the lower dynamic comfort threshold both shift over time to follow an RF power curve during at least a portion of a processing run in which the substrate is being processed in the processing chamber, and wherein the RF power curve, the upper dynamic comfort threshold, and the lower dynamic comfort threshold are derived from empirical data samples of measured delivered RF power collected during processing runs of substrates that do not have gapping, bowing, or shifting issues.
17 . The substrate processing tool of claim 16 , wherein the behavior of the delivered RF power is observed from changes in a magnitude of a reactive component with respect to a magnitude of a real component of the delivered RF power.
18 . The substrate processing tool of claim 16 , wherein the behavior of the RF power is observed by comparing a voltage-current phase angle difference between a real RF power component and a reactive RF power component of the RF power delivered to the processing chamber.
19 . The substrate processing tool of claim 18 , where a degree of the voltage-current phase angle difference is proportional to a size of the gap and/or a degree of the shifting.
20 . The substrate processing tool of claim 16 , wherein presence of the gap and/or the shifting of the substrate is determined by ascertaining an impedance magnitude change of a real RF power component and/or a reactive RF power component of the RF power delivered to the processing chamber.
21 . The substrate processing tool of claim 20 , wherein the impedance magnitude is proportional to the size of the gap and/or the degree of the shifting.
22 . The substrate processing tool of claim 16 , wherein the controller is configured to set a data flag in response to detecting the gap and/or the shifting of the substrate, and wherein the controller is configured to perform the recovery process operation for the substrate in response to the data flag being set.
23 . The substrate processing tool of claim 16 , wherein the probe includes a Voltage/Current (“V/I”) meter, the V/I meter arranged to measure:
(a) voltage;
(b) current; and
(c) a phase angle between the voltage and the current.
24 . The substrate processing tool of claim 23 , wherein the V/I meter is coupled in series between a RF source and a RF electrode, wherein the V/I meter is embedded in a substrate pedestal defining the support surface, and wherein the RF source is used for delivering the RF power to the processing chamber.
25 . A substrate processing tool including a controller, operating in cooperation with a Voltage or Current (“V/I”) meter capable of measuring RF characteristics indicating observed behavior of RF power delivered to a processing chamber of the substrate processing tool, the controller being configured to receive one or more data samples derived from the RF characteristics measured by the V/I meter, and set a data flag indicating that a substrate undergoing processing in the processing chamber as having a gap and/or having shifted, relative to a surface of a substrate pedestal supporting the substrate in the processing chamber based on the one or more data samples derived from the observed behavior of the RF power delivered to the processing chamber as measured by the V/I meter exceeding an upper dynamic comfort threshold or a lower dynamic comfort threshold, wherein the upper dynamic comfort threshold and the lower dynamic comfort threshold both shift over time to follow an RF power curve during at least a portion of a processing run in which the substrate is being processed in the processing chamber, and wherein the RF power curve, the upper dynamic comfort threshold, and the lower dynamic comfort threshold are derived from empirical data samples of measured delivered RF power collected during processing runs of substrates that do not have gapping, bowing, or shifting issues.
26 . The substrate processing tool of claim 25 , wherein the behavior of the RF power is observed by comparing a voltage-current phase angle difference between a real RF power component and a reactive RF power component of the RF power delivered to the processing chamber.
27 . The substrate processing tool of claim 25 , wherein behavior of the RF power is observed by comparing a change in impedance magnitude between a real RF power component and a reactive RF power component of the RF power delivered to the processing chamber.
28 . The substrate processing tool of claim 25 , wherein the V/I meter is arranged to measure one or more parameters of a real RF component and a reactive RF component of the RF power supplied to the processing chamber, the one or more parameters including:
(a) voltage;
(b) current; and
(c) phase angle.
29 . The substrate processing tool of claim 16 , wherein the controller is configured to:
generate the RF power curve from the empirical data samples of the measured delivered RF power collected from the processing runs of the substrates that do not have gapping, bowing, or shifting issues; and
derive the upper dynamic comfort threshold and the lower dynamic comfort threshold from the generated RF power curve.
30 . The substrate processing tool of claim 25 , wherein the controller is configured to:
generate the RF power curve from the empirical data samples of the measured delivered RF power collected from the processing runs of the substrates that do not have gapping, bowing, or shifting issues; and
derive the upper dynamic comfort threshold and the lower dynamic comfort threshold from the generated RF power curve.