Process module tuning

• US 7,415,312 B2
• Filed: 05/26/2004
• Issued: 08/19/2008
• Est. Priority Date: 05/25/2004
• Status: Expired due to Fees

• Current Assignee: SensArray Corp. (KLA Corporation)
• Original Assignee: SensArray Corp. (KLA Corporation)
• Inventors: Parker, Jeffrey M., Barnett, James R. Jr., Ekblad, Mark K.
• Primary Examiner(s): DeCady; Albert
• Assistant Examiner(s): CHANG, SUNRAY
• Application Number:
  US10/855,696
• Publication Number:
  US 20050267606A1
• Time in Patent Office: 1,546 Days
• Field of Search: 700/29, 700/44, 738/661, 702/94, 702/127, 219/390
• US Class Current: 700/29
• CPC Class Codes: G05B 13/042 in which a parameter or coefficient is automatically adjusted to optimise the performance
• CPC Class Codes: G05D 23/1931 to control the temperature of one space

Abstract

A process module tuning method characterizes a process module by gathering data using a process condition measuring device to measure process outputs while inputs are excited. The data is used to identify a dynamic process model. The dynamic process model is then be used to determine process input settings that will produce desired outputs. For multi-zone process modules, the interactions between zones may be modeled.

Claims

1. A method of characterizing a process module having a plurality of process inputs that affect a process condition and a first plurality of sensors of the process condition whose outputs are used by a controller of the plurality of process inputs to maintain a desired process condition, using a process condition measuring device having a plurality of sensors that measure the process condition, comprising:

placing the process condition measuring device in the process module;

providing a first excitation to at least a first of the plurality of process inputs and providing a second excitation to at least a second of the plurality of process inputs, while recording the outputs of the second plurality of sensors; and

using the recorded output of the plurality of sensors to develop a model of relationships between the process condition and the plurality of process inputs, including a first relationship between the process condition at a first of the second plurality of sensors and the first process input and a second relationship between the process condition at the first of the second plurality of sensors and the second process input,

wherein the first plurality of sensors are part of the process module and wherein the process condition measuring device and the second plurality of sensors are separate from and removable from the process module.

2. The method of claim 1 wherein the process module is a multi-zone hot-plate having at least a first zone and a second zone, the first process input is a heat input of the first zone, the second process input is a heat input of the second zone and the process condition is temperature.

3. The method of claim 2 wherein the plurality of process inputs are heat inputs to a plurality of zones of the multi-zone hot-plate and the model provides a relationship between each heat input and the temperature measurement at each of the second plurality of sensors.

4. The method of claim 3 wherein the plurality of sensors may be selected from among a number of the second plurality of sensors of the PCMD and wherein data from unselected ones of the second plurality of sensors is not used in developing the model.

5. The method of claim 4 wherein data from unselected sensors is used to derive an intermediate model, the intermediate model being subsequently modified to eliminate dependence on data from the unselected sensors in the model.

6. The method of claim 5 wherein the intermediate model is a gain matrix and the model is a gain matrix that has fewer components than the intermediate model.

7. The method of claim 2 wherein the first excitation of the first process input is an increase in heat input to the first zone, the second excitation of the second process input is an increase in heat input to the second zone.

8. The method of claim 1 wherein the plurality of process inputs are controlled so that a process input is modified in response to a change in an output of one of the first plurality of sensors.

9. The method of claim 8 further comprising recording the plurality of process inputs and recording the outputs of the first plurality of sensors and using the recorded process inputs and the recorded outputs of the first plurality of sensors to develop the model.

10. The method of claim 8 wherein the controller includes a feedback controller according to a plurality of parameters, further comprising using the model to obtain a value for a controller parameter.

11. The method of claim 1 wherein the model of relationships between the process condition and the plurality of process inputs includes a dynamic relationship between at least one process input and the process condition at at least one of the second plurality of sensors.

12. The method of claim 1 further comprising using the model to determine process input values of the plurality of process inputs needed to produce a desired plurality of process condition values in the process module.

13. An apparatus for characterizing a process module that has first plurality of sensors that measure the process condition at a plurality of locations within the process module to control a plurality of process inputs that affect a process condition of the process module, comprising:

a process condition measuring device having a plurality of sensors that measure the process condition at a plurality of locations when placed in the process module; and

a modeling unit that receives process condition data from the first and second plurality of sensors and generates a model of a set of relationships between the plurality of controlled process inputs and the process condition at the plurality of sensors including a first relationship between a first process input and the process condition at one of the second plurality of sensors and a second relationship between a second process input and the process condition at the one sensor,

wherein the first plurality of sensors are part of the process module and wherein the process condition measuring device and the second plurality of sensors are separate from and removable from the process module.

14. The apparatus of claim 13 wherein the process condition measuring device comprises:

a substrate;

the second plurality of sensors that measure the process condition, the sensors attached to the substrate; and

a memory that records the output of the second plurality of sensors.

15. The apparatus of claim 13 wherein a controlled input is controlled in response to a signal, the modeling unit receiving the controlled input and the signal.

16. A method of determining an operating parameter value for a controller of a hotplate having a plurality of heating zones, individual heating zones having a heating element that outputs power and a hot-plate-temperature sensor that measures a heating zone temperature, the output power of the heating elements being determined by the controller in response to the heating zone temperatures measured by the hot-plate temperature sensors according to a plurality of operating parameters, using a process condition measuring device that has a plurality of wafer-temperature sensors, wherein the hot-plate temperature sensors are part of the hot-plate and wherein the process condition measuring device and the wafer temperature sensors are separate from and removable from the hot-plate, comprising:

placing the process condition measuring device on the hot-plate such that a first wafer-temperature sensor of the plurality of wafer-temperature sensors is proximate to a first heating zone, wherein the characteristics of the process condition measuring device include thermal characteristics that resemble those an article to be heated by the hotplate so that any temperatures measured by the plurality of device sensors when the process condition measuring device is subjected to heat input from the heating elements are similar to those that would exist when the article is subjected to the same heat input from the heating elements;

powering the heating elements of the plurality of heating zones while recording the temperatures of the plurality of wafer-temperature sensors and the plurality of hot-plate temperature sensors;

using the recorded temperatures of the plurality of wafer-temperature sensors and the plurality of hot-plate temperature sensors to develop a model of the temperatures of the plurality of wafer-temperature sensors and the heating zone temperatures of the plurality of heating zones including the relationship between the temperature of the first wafer-temperature sensor and the heating zone temperature of a second heating zone; and

deriving a value of at least one of the operating parameter value for the controller from the model.

17. The method of claim 16 wherein the at least one of the plurality of operating parameters includes at least one of:

a temperature setpoint, a temperature setpoint offset, a maximum power value, a minimum power value or a PID constant of a PID controller.

18. The method of claim 16 wherein the at least one operating parameter value that is determined is a temperature setpoint or a constant of a feedback controller.

19. The method of claim 16 further comprising recording the power outputs of the plurality of heating zones while recording the temperatures of the plurality of wafer-temperature sensors.

20. The method of claim 16 further comprising configuring the controller to operate according to the derived at least one operating parameter value and subsequently, with the process condition measuring device on the hot-plate, powering the heating elements of the plurality of heating zones to achieve desired temperatures while recording the temperatures of the plurality of wafer-temperature sensors and deriving at least a second operating parameter value for the controller from differences between the recorded temperatures and the desired temperatures.

21. A method of calibrating an article processing module having a plurality of processing zones that individually have their own input that affects a value of a processing condition therein and a module sensor measuring the processing condition therein, wherein the processing conditions of the individual zones are coupled with one another, and a controller that operates to receive the module sensor measurements and calculate therefrom the individual process zone inputs to maintain defined values of the processing conditions in the individual zones of the module, comprising:

positioning within the processing module a process condition measuring device having characteristics comparable to those of the article and with a plurality of device sensors of the processing condition distributed thereon, the measuring device being positioned in the module with the plurality of device sensors distributed across the plurality of zones, wherein the characteristics of the process condition measuring device are selected such that when the measuring device is subjected to process inputs from the individual zones of the module the processing conditions measured by the plurality of device sensors are similar to processing conditions that would exist when the article is subjected to the same process inputs from the same individual process zones,

varying the processing inputs of the plurality of zones over a period of time and measuring the processing conditions therein by both module sensor measurements and outputs of the device sensors over that period of time,

developing a model of relationships between the processing inputs and the measurements of the module sensors and the outputs of the device sensors,

determining from the model a set of calibration values for the module sensors,

removing the measuring device from the processing module and placing the article to be processed therein, and

adjusting the operation of the process module controller while processing the article to calculate values of the individual process zone inputs with use of the calibration values.

22. The method of claim 21, wherein

the set of calibration values determined from the model include offsets of the module sensor measurements, and

adjusting the operation of the process module controller includes use of the offset values of the module sensor measurements.

23. The method of claim 22, wherein the process module includes a hot-plate, the processing condition includes temperature and the inputs to the processing zones are applied to individual heaters of the processing zones and the characteristics of the process condition measuring device include thermal characteristics that resemble those the article so that any temperatures measured by the plurality of device sensors when the process condition measuring device is subjected to heat input from the individual heaters are similar to those that would exist when the article is subjected to the same heat input from the individual heaters.

24. The method of claim 22, wherein the article being processed includes a substrate from which either an integrated circuit or flat panel display is being formed.

25. The method of claim 21, wherein the article includes a substrate and the processing module operates to perform one or more of a group of processes that comprises etching the substrate, depositing layers on the substrate, adding dopants to the substrate and forming patterns on the substrate.