Plasma processing apparatus
View Patent ↗A plasma processing apparatus including: a monitor device which monitors a process quantity generated at plasma processing; a monitor value estimation unit which has monitor quantity variation models for storing change of a monitor value of the process quantity in accordance with the number of processed specimens and which estimates a monitor value for a process of a next specimen by referring to the monitor quantity variation models; and a control quantity calculation unit which stores a relation between a control quantity for controlling the process quantity of the vacuum processing device and a monitor value and which calculates the control quantity based on a deviation of the estimated monitor value from a target value to thereby control the process quantity for the process of the next specimen. Thus, a process model indicating variation of the state of a process processing apparatus can be added to a control loop in such run-to-run control that process conditions are changed according to each wafer process, so that stable processed results can be obtained even when variation occurs in processes.
1. A plasma processing apparatus for applying plasma processing by run-to-run control to specimens that are disposed in a vacuum processing chamber by using plasma generated in the vacuum processing chamber, comprising:
a first database that stores a first monitor value variation model indicating a correlation between a number of specimens processed during a period from execution of wet cleaning to execution of a next process and a monitor value of a process quantity obtained when specimens of this number have been processed;
a second database that stores a second monitor value variation model indicating a correlation between a number of specimens processed during a period from start of a lot process to end of the lot process and a monitor value of a process quantity obtained when specimens of this number have been processed;
a process history management unit that stores the number of specimens processed from execution of wet cleaning to execution of a next process and the number of specimens processed from start of a lot process to end of the lot process;
a monitor value estimation unit configured to obtain a composite model of the first monitor value variation model and the second monitor value variation model and configured to calculate a monitor value for a next process based on the composite model;
a third database that stores a control model indicating a correlation between a control quantity for controlling a process quantity of the vacuum processing chamber and a quantity of change of a monitor value; and
a control quantity calculation unit configured to calculate a control quantity for the next process which corresponds to a deviation of the monitor value calculated by the monitor value estimation unit and a target value based on the control model;
wherein the monitor value estimation unit comprises a monitor value variation model movement unit configured to move the first monitor value variation model for processing just after aging;
wherein the first monitor value variation model is a function of processed wafers from wet cleaning, and at least one long term variation model coefficient;
wherein the second monitor variation model is a function of the number of processed wafers in a lot and at least one short-term model coefficient.
2. The plasma processing apparatus according to claim 1 , wherein the first monitor quantity variation model is reset whenever wet cleaning is performed.
3. The plasma processing apparatus according to claim 1 , wherein the next process is a same product process or cleaning process as a current process.
4. The plasma processing apparatus according to claim 1 , wherein a current process is a product process and the next process is a cleaning process.
5. The plasma processing apparatus according to claim 1 , wherein a current process is a cleaning process and the next process is a product process.
6. The plasma processing apparatus according to claim 1 , wherein the first monitor quantity variation model is represented by the expression:
Y 1 =A 1 ×B 1 (N 1 +C 1 ) +D 1
in which Y 1 is a process monitor value, which is a plasma light emission monitor value, N 1 is a number of processed wafers from wet cleaning, and A 1 , B 1 , C 1 and D 1 are long-term variation model coefficients.
7. The plasma processing apparatus according to claim 1 , wherein the second monitor quantity variation model is represented by the expression:
Y 2 =A 2 ×N 2 2 +B 2 ×N 2 +C 2
in which Y 2 is a process monitor value, which is a plasma light emission monitor value, N 2 is a number of processed wafers in a lot, and A 2 , B 2 and C 2 are short-term variation model coefficients.
8. A plasma processing apparatus for applying plasma processing by run-to-run control to specimens that are disposed in a vacuum processing chamber by using plasma generated in the vacuum processing chamber, comprising:
a first database that stores a first monitor value variation model indicating a correlation between a number of specimens processed during a period from execution of wet cleaning to execution of a next process and a monitor value of a process quantity obtained when specimens of this number have been processed;
a second database that stores a second monitor value variation model indicating a correlation between a number of specimens processed during a period from start of a lot process to end of the lot process and a monitor value of a process quantity obtained when specimens of this number have been processed;
a process history management unit that stores the number of specimens processed from execution of wet cleaning to execution of a next process and the number of specimens processed from start of a lot process to end of the lot process;
a monitor value estimation unit configured to obtain a composite model of the first monitor value variation model and the second monitor value variation model and configured to calculate a monitor value for a next process based on the composite model;
a third database that stores a control model indicating a correlation between a control quantity for controlling a process quantity of the vacuum processing chamber and a quantity of change of a monitor value; and
a control quantity calculation unit configured to calculate a control quantity for the next process which corresponds to a deviation of the monitor value calculated by the monitor value estimation unit and a target value based on the control model;
wherein the monitor value estimation unit comprises a monitor value variation model movement unit configured to move the first monitor value variation model or the second monitor value variation model so as to be put on a monitor value for a current process without execution of run-to-run control;
wherein the first monitor value variation model is a function of processed wafers from wet cleaning and at least one long term variation model coefficient;
wherein the second monitor variation model is a function of the number of processed wafers in a lot and at least one short-term model coefficient.
9. A plasma processing apparatus for applying plasma processing by run-to-run control to specimens that are disposed in a vacuum processing chamber by using plasma generated in the vacuum processing chamber, comprising:
a first database that stores a first monitor value variation model indicating a correlation between a number of specimens processed during a period from execution of wet cleaning to execution of a next process and a monitor value of a process quantity obtained when specimens of this number have been processed;
a second database that stores a second monitor value variation model indicating a correlation between a number of specimens processed during a period from start of a lot process to end of the lot process and a monitor value of a process quantity obtained when specimens of this number have been processed;
a process history management unit that stores the number of specimens processed from execution of wet cleaning to execution of a next process and the number of specimens processed from start of a lot process to end of the lot process;
a monitor value estimation unit configured to obtain a composite model of the first monitor value variation model and the second monitor value variation model and configured to calculate a monitor value for a next process based on the composite model;
a third database that stores a control model indicating a correlation between a control quantity for controlling a process quantity of the vacuum processing chamber and a quantity of change of a monitor value; and
a control quantity calculation unit configured to calculate a control quantity for the next process which corresponds to a deviation of the monitor value calculated by the monitor value estimation unit and a target value based on the control model;
wherein the monitor value estimation unit comprises a monitor value variation model movement unit configured to move the second monitor value variation model in parallel so as to be put on a monitor value for a current process without execution of run-to-run control;
wherein the first monitor value variation model is a function of processed wafers from wet cleaning and at least one long term variation model coefficient;
wherein the second monitor variation model is a function of the number of processed wafers in a lot and at least one short-term model coefficient.