Method of characterizing a chamber based upon concurrent behavior of selected plasma parameters as a function of plural chamber parameters
First Claim
1. A method of operating a plasma reactor chamber with respect to plural plasma parameters, by controlling plural chamber parameters, said method comprising:
- characterizing the reactor chamber by performing the steps of;
a. for each one of said chamber parameters, ramping an input level of the one chamber parameter while sampling RF electrical parameters at an RF bias power input to said wafer support pedestal and computing from each sample of said RF electrical parameters the values of said plural plasma parameters, and storing said values with the corresponding levels of said one chamber parameter as corresponding chamber parameter data;
b. for each one of said chamber parameters, deducing, from the corresponding chamber parameter data, a single variable function for each of said plural plasma parameters having said one chamber parameter as an independent variable, so as to produce a set of said functions corresponding to all of said chamber parameters;
c. from said set of functions, constructing surfaces defining simultaneous values of all of said chamber parameters, each respective surface corresponding to each constant value of one of said plural plasma parameters, said surfaces spanning a range of said values, and storing said surfaces;
controlling a plasma in the chamber during processing of a production wafer in the chamber in accordance with user-selected values of each of said plural plasma parameters by performing the following steps;
a. for each one of said plural plasma parameters, fetching a relevant surface of constant value corresponding to the user-selected value of said one plasma parameter, and determining an intersection of the relevant surfaces which defines a target value for each of said chamber parameters; and
b. setting each of said chamber parameters to the corresponding target value.
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Abstract
The invention involves a method of characterizing a plasma reactor chamber through the behavior of many selected plasma parameters as functions of many selected chamber parameters. The plasma parameters may be selected from a group including ion density, wafer voltage, etch rate and wafer current or other plasma parameters. The chamber parameters are selected from a group including source power, bias power, chamber pressure, magnetic coil current in different magnetic coils, gas flow rates in different gas injection zones and species composition of the gas in different gas injection zones.
152 Citations
17 Claims
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1. A method of operating a plasma reactor chamber with respect to plural plasma parameters, by controlling plural chamber parameters, said method comprising:
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characterizing the reactor chamber by performing the steps of; a. for each one of said chamber parameters, ramping an input level of the one chamber parameter while sampling RF electrical parameters at an RF bias power input to said wafer support pedestal and computing from each sample of said RF electrical parameters the values of said plural plasma parameters, and storing said values with the corresponding levels of said one chamber parameter as corresponding chamber parameter data; b. for each one of said chamber parameters, deducing, from the corresponding chamber parameter data, a single variable function for each of said plural plasma parameters having said one chamber parameter as an independent variable, so as to produce a set of said functions corresponding to all of said chamber parameters; c. from said set of functions, constructing surfaces defining simultaneous values of all of said chamber parameters, each respective surface corresponding to each constant value of one of said plural plasma parameters, said surfaces spanning a range of said values, and storing said surfaces; controlling a plasma in the chamber during processing of a production wafer in the chamber in accordance with user-selected values of each of said plural plasma parameters by performing the following steps; a. for each one of said plural plasma parameters, fetching a relevant surface of constant value corresponding to the user-selected value of said one plasma parameter, and determining an intersection of the relevant surfaces which defines a target value for each of said chamber parameters; and b. setting each of said chamber parameters to the corresponding target value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of operating a plasma reactor chamber with respect to plural plasma parameters, by controlling plural chamber parameters, said method comprising:
characterizing the reactor chamber by performing the steps of; a. for each one of said chamber parameters, ramping an input level of the one chamber parameter while sampling RF electrical parameters at an RF bias power input to said wafer support pedestal and computing from each sample of said RF electrical parameters the values of said plural plasma parameters, and storing said values with the corresponding levels of said one chamber parameter as corresponding chamber parameter data; b. for each one of said chamber parameters, deducing, from the corresponding chamber parameter data, a single variable function for each of said plural plasma parameters having said one chamber parameter as an independent variable, so as to produce a set of said functions corresponding to all of said chamber parameters; c. from said set of functions, constructing surfaces defining simultaneous values of all of said chamber parameters, each respective surface corresponding to each constant value of one of said plural plasma parameters, said surfaces spanning a range of said values, and storing said surfaces; wherein the step of constructing surfaces defining simultaneous values of all of said chamber parameters further comprises the following carried out for each one of said plural plasma parameters; combining the single variable functions dependent upon respective single variables of source power, bias power and chamber pressure into a single composite function having three variables of source power, bias power and chamber pressure; setting the composite function equal to a succession of values of the respective plasma parameter. - View Dependent Claims (9)
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10. A method of operating a plasma reactor chamber with respect to plural plasma parameters, by controlling plural chamber parameters, said method comprising:
characterizing the reactor chamber by performing the steps of; a. for each one of said chamber parameters, ramping an input level of the one chamber parameter while sampling RF electrical parameters at an RF bias power input to said wafer support pedestal and computing from each sample of said RF electrical parameters the values of said plural plasma parameters, and storing said values with the corresponding levels of said one chamber parameter as corresponding chamber parameter data; b. for each one of said chamber parameters, deducing, from the corresponding chamber parameter data, a single variable function for each of said plural plasma parameters having said one chamber parameter as an independent variable, so as to produce a set of said functions corresponding to all of said chamber parameters; c. from said set of functions, constructing surfaces defining simultaneous values of all of said chamber parameters, each respective surface corresponding to each constant value of one of said plural plasma parameters, said surfaces spanning a range of said values, and storing said surfaces; wherein the sampling RF electrical parameters at an RF bias power input to said wafer support pedestal comprises sensing an input impedance, an input current and an input voltage to a transmission line coupled between a bias power impedance match circuit and an electrode within the wafer pedestal; wherein the computing from each sample of said RE electrical parameters the values of plural plasma parameters is carried out separately for plasma parameters of ion density, wafer voltage and etch rate. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
Specification