# US 11,029,668 B2 · Systems and methods for calibrating scalar field contribution values for a limited number of sensors including a temperature value of an electrostatic chuck and estimating temperature distribution profiles based on calibrated values

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- Number: US 11,029,668 B2
- Document ID: US11029668B2
- Status: Granted
- Kind: B2
- Application number: 16/506,386
- Filed: 2019-07-09
- Published: 2019-10-31
- Granted: 2021-06-08
- Earliest claimed: 2015-06-22
- Assignees: Lam Research Corporation
- Applicants: Lam Research Corporation
- Inventors: Marcus Musselman; Andrew D. Bailey, III
- Web page: https://patentgrep.com/patent/US11029668B2

## CPC

- G05B 19/418: Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
- G01K 3/06: in respect of space
- G01K 15/005: {Calibration}
- G05B 2219/2602: Wafer processing
- G05B 2219/45031: Manufacturing semiconductor wafers
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00)

## Abstract

A system includes sensors, an interface and a controller. The interface receives feedback signals from the sensors. At least some of the sensors are disposed in an electrostatic chuck. The feedback signals are indicative respectively of fields of a heating plate of the electrostatic chuck. The controller, based on the fields and sets of calibration values, estimates values of a first field respectively for multiple points on a substrate. Each of the sets of calibration values corresponds respectively to one of multiple actuators. The calibration values, in each of the sets of calibration values, define amounts of contribution provided by a respective one of the actuators to the first field for the points. The controller changes physical states of the actuators based on the estimated values of the first field of the points to provide a predetermined temperature distribution profile across the electrostatic chuck.

## Claims

### Claim 1

A system comprising:
a plurality of sensors;
an interface configured to receive a first plurality of feedback signals from the plurality of sensors, wherein at least some of the plurality of sensors are disposed in an electrostatic chuck, and wherein the first plurality of feedback signals are indicative respectively of a plurality of fields of a heating plate of the electrostatic chuck; and
one or more controllers configured to, based on the plurality of fields and a plurality of sets of calibration values, estimate values of a first field respectively for a plurality of points on a substrate,
wherein
the plurality of fields includes the first field,
each of the plurality of sets of calibration values corresponds respectively to one of a first plurality of actuators,
the plurality of sets of calibration values for each of the plurality of sensors are indicative of thermal energy contributions corresponding respectively to the first plurality of actuators,
the calibration values, in each of the plurality of sets of calibration values, define amounts of contribution provided by a respective one of the first plurality of actuators to the first field for the plurality of points,
each of the plurality of sets of calibration values includes calibration values corresponding respectively to the plurality of points, and
the one or more controllers is configured to change physical states of the first plurality of actuators based on the estimated values of the first field of the plurality of points to provide a predetermined temperature distribution profile across the electrostatic chuck.

### Claim 2 (depends on 1)

The system of claim 1, wherein the one or more controllers is configured to:
select a point at a radius, wherein the radius is different than radii corresponding to locations of the plurality of sensors in a chamber;
estimate an azimuthally averaged field of the selected point based on estimates of the plurality of fields; and
estimate one or more of the values of the first field of the substrate based on the azimuthally averaged field.

### Claim 3 (depends on 1)

The system of claim 1, wherein:
the one or more controllers is configured to, prior to changing the physical states of the first plurality of actuators, select a predetermined set of fields and adjust parameters of the first plurality of actuators based on the predetermined set of fields; and
the first plurality of feedback signals from the plurality of sensors are generated based on the adjusted parameters.

### Claim 4 (depends on 3)

The system of claim 3, wherein the one or more controllers comprise:
a first controller configured to select the predetermined set of fields; and
a second controller configured to adjust the parameters of the first plurality of actuators based on the predetermined set of fields.

### Claim 5 (depends on 3)

The system of claim 3, further comprising a chamber, wherein:
one or more controllers is configured to adjust parameters of a second plurality of actuators based on a second predetermined set of fields; and
the chamber comprises the first plurality of actuators and the second plurality of actuators.

### Claim 6 (depends on 5)

The system of claim 5, wherein:
the second set of predetermined fields are based on an etch recipe; and
the etch recipe includes nominal set points for radio frequency power levels, gas flow rates, or target substrate temperatures.

### Claim 7 (depends on 5)

The system of claim 5, wherein the one or more controllers is configured to:
coarsely adjust the first field of the substrate by adjusting the parameters of the first plurality of actuators; and
finely adjust the first field of the substrate by adjusting the parameters of the second plurality of actuators, wherein a field range over which the coarse adjustment occurs is greater than a field range over which the fine adjustment occurs.

### Claim 8 (depends on 5)

The system of claim 5, wherein the plurality of sets of calibration values for each of the plurality of sensors are indicative of thermal energy contributions corresponding respectively to the second plurality of actuators.

### Claim 9 (depends on 8)

The system of claim 8, further comprising a calibration module configured to set the plurality of sets of calibration values based on settings of the second plurality of actuators and settings of a plurality of macro-zones.

### Claim 10 (depends on 9)

The system of claim 9, wherein:
the settings of the plurality of macro-zones comprise thermal control resistances of the substrate and four zone offsets; and
the four zone offsets refer to impact of the second plurality of actuators on the plurality of fields.

### Claim 11 (depends on 1)

The system of claim 1, wherein some of the plurality of points on the substrate are located at the some of the plurality of sensors.

### Claim 12 (depends on 1)

The system of claim 1, wherein some of the plurality of points on the substrate are not located at the some of the plurality of sensors.

### Claim 13 (depends on 1)

The system of claim 1, wherein:
the plurality of sensors are disposed in a plurality of zones of a chamber, wherein a first one or more of the plurality of zones is outside the electrostatic chuck and a second one or more of the plurality of zones includes a portion of the electrostatic chuck; and
the estimated values include estimated temperatures of the plurality of zones.

### Claim 14 (depends on 1)

The system of claim 1, wherein a number of actuators included in the first plurality of actuators is greater than a number of sensors in the plurality of sensors.

### Claim 15 (depends on 1)

The system of claim 1, wherein:
the first plurality of actuators are in a first plurality of zones of the electrostatic chuck;
the plurality of sensors and the first plurality of actuators are disposed in the electrostatic chuck; and
a number of actuators in each of the first plurality of zones is greater than a number of sensors in the electrostatic chuck.

### Claim 16 (depends on 1)

The system of claim 1, wherein:
the plurality of sensors include temperature probes; and
the one or more controllers is configured to
estimate an azimuthally averaged temperature based on (i) temperatures indicated by the temperature probes, and (ii) the plurality of sets of calibration values for each of the plurality of sensors, and
adjust operation of the first plurality of actuators based on the azimuthally averaged temperatures.

### Claim 17 (depends on 1)

The system of claim 1, wherein at least some of the first plurality of actuators are implemented in the electrostatic chuck.

### Claim 18 (depends on 1)

The system of claim 1, wherein the one or more controllers is configured to, subsequent to generating the plurality of calibration values and during the processing of the substrate, adjust at least one of current, voltage, frequency or duty cycle of the first plurality of actuators to change the physical states of the first plurality of actuators based on the estimated values.

### Claim 19 (depends on 1)

The system of claim 1, Therein the plurality of points are located respectively at the plurality of sensors.

### Claim 20

A system comprising:
a plurality of sensors;
an interface configured to receive a first plurality of feedback signals from the plurality of sensors, wherein at least some of the plurality of sensors are disposed in an electrostatic chuck, and wherein the first plurality of feedback signals are indicative respectively of a plurality of fields of a heating plate of the electrostatic chuck; and
one or more controllers configured to, based on the plurality of fields and a plurality of sets of calibration values, estimate values of a first field respectively for a plurality of points on a substrate,
wherein
the plurality of fields includes the first field,
each of the plurality of sets of calibration values corresponds respectively to one of a first plurality of actuators,
the calibration values, in each of the plurality of sets of calibration values, define amounts of contribution provided by a respective one of the first plurality of actuators to the first field for the plurality of points, and
the one or more controllers is configured to change physical states of the first plurality of actuators based on the estimated values of the first field of the plurality of points to provide a predetermined temperature distribution profile across the electrostatic chuck,
the plurality of sensors include a first sensor,
the first plurality of actuators include a first actuator and a second actuator,
the plurality of sets of calibration values for the first sensor include a first calibration value and a second calibration value,
the first calibration value of the first sensor is proportional to an amount of contribution provided by the first actuator to the one of the plurality of fields, and
the second calibration value of the first sensor is proportional to an amount of contribution provided by the second actuator to the one of the plurality of fields.