Techniques for controlling precursors in chemical deposition processes

1. An apparatus, comprising:

a processor; and

a memory unit coupled to the processor, including a flux control routine, the flux control routine operative on the processor to monitor a precursor flow, the flux control routine comprising:

a flux calculation processor configured to determine a precursor flux value based upon a change in detected signal intensity received from a cell of a gas delivery system to deliver a precursor;

a temperature control processor, configured to:

determine a flux error value based upon the precursor flux value;

determine a temperature adjustment ΔT, based upon the flux error value;

calculate a new set of temperature setpoints to be applied to the ampoule; and

an end-of-life processor, the end-of-life processor configured to: check for an end-of ampoule-life condition when the new set of temperature setpoints is not within the predetermined set of temperature limits.

2. The apparatus of claim 1 , the flux calculation processor configured to determine the precursor flux value by:

receiving a first reference signal in the cell, generated at a first instance, the first reference signal indicative of a detector performance at the first instance for a detector, the detector to detect a light intensity from a light source;

receiving a background signal, generated at the first instance, the background signal being generated by the detector;

receiving a second reference signal, generated at a second instance, subsequent to the first instance, the second reference signal indicative of the detector performance at the second instance for the detector; and

receiving a precursor signal, generated at a third instance, subsequent to the first instance, when the precursor is flowing in the cell.

3. The apparatus of claim 1 , the flux calculation processor configured to calculate an integrated flux of the precursor by determining the precursor flux value at a plurality of instances.

4. The apparatus of claim 2 , the temperature control processor configured to:

determine a warning band condition based upon the precursor flux value; and

adjust the temperature of an ampoule based upon the warning band condition.

5. The apparatus of claim 1 , the temperature control processor configured to adjust the temperature by:

determining a temperature adjustment ΔT, where ΔT=P*€+D*d €/dt+I*∫€/dt, where P, I and D are a proportional, integral, and derivative gains, and where € is an error based upon current temperature limits of the ampoule.

6. The apparatus of claim 1 , the temperature control processor configured to adjust the temperature by:

determining a flux error value based upon the precursor flux value;

determining a temperature adjustment ΔT, based upon the flux error value;

calculating a new set of temperature setpoints to be applied to the ampoule; and

applying the new set of temperature setpoints to control heating of the ampoule when the new set of temperature setpoints are within a predetermined set of temperature limits.

7. The apparatus of claim 6 , the flux control routine further comprising an end-of-life processor, the end-of-life processor configured to:

recalculate ΔT to generate a conservative ΔT based upon a most conservative limit when the end-of ampoule life condition has not been met; and

calculate the new set of temperature setpoints to be applied to the ampoule based upon the conservative ΔT.

8. The apparatus of claim 1 , the flux control routine further comprising an excursion processor, the excursion processor configured to:

determine a fault condition based upon the precursor flux value; and

send a notification signal of an excursion, when a substrate being processed is during the fault condition is not a first substrate.

9. The apparatus of claim 1 , the flux control routine further comprising a clog detection processor, the clog detection processor configured to:

receive a cell pressure reading for the cell;

receive the precursor flux value; and

determine a clog location based upon the cell pressure reading and precursor flux value.

10. An apparatus for controlling precursor flow, comprising:

a source to output a precursor;

a sensor assembly communicatively coupled to the source, the sensor assembly comprising:

a cell, coupled to the source, to receive and conduct the precursor;

a light source, disposed on a first side of the cell, to transmit light into the cell; and

a detector, disposed on a second side of the cell, opposite the light source, to detect light transmitted through the cell; and

a control system, the control system arranged to determine a precursor flux value based upon a change in detected light intensity received from the cell during flow of the precursor through the cell, the control system comprising:

a flux calculation processor configured to determine a precursor flux value based upon the change in detected signal intensity;

a temperature control processor, configured to:

determine a flux error value based upon the precursor flux value;

determine a temperature adjustment ΔT, based upon the flux error value; and

calculate a new set of temperature setpoints to be applied to the ampoule; and

an end-of-life processor, the end-of-life processor configured to: check for an end-of ampoule-life condition when the new set of temperature setpoints is not within the predetermined set of temperature limits.

11. An apparatus, comprising:

a processor; and

a memory unit coupled to the processor, including a flux control routine, the flux control routine operative on the processor to monitor a precursor flow, the flux control routine comprising:

a flux calculation processor configured to:

determine a precursor flux value based upon a change in detected signal intensity received from a cell of a gas delivery system to deliver a precursor; and

a clog detection processor, the clog detection processor configured to:

receive a cell pressure reading for the cell;

receive the precursor flux value; and

determine a clog location based upon the cell pressure reading and precursor flux value.

12. The apparatus of claim 11 , the flux control routine further comprising a temperature control processor, configured to determine a warning band condition based upon the precursor flux value; and adjust a temperature of an ampoule based upon the warning band condition.

13. The apparatus of claim 12 , the temperature control processor configured to adjust the temperature by:

determining an error value based upon the precursor flux value;

determining a temperature adjustment ΔT, based upon the error value;

calculating a new set of temperature setpoints to be applied to the ampoule; and

applying the new set of temperature setpoints to control heating of the ampoule when the new set of temperature setpoints are within a predetermined set of temperature limits.

14. The apparatus of claim 11 , the flux control routine further comprising an excursion processor, the excursion processor configured to:

determine a fault condition based upon the precursor flux value; and

send a notification signal of an excursion, when a substrate being processed is during the fault condition is not a first substrate.

15. The apparatus of claim 11 , the flux control routine further comprising an end-of-life processor, the end-of-life processor configured to:

check for an end-of ampoule-life condition when the new set of temperature setpoints is not within the predetermined set of temperature limits;

recalculate ΔT to generate a conservative ΔT based upon a most conservative limit when the end-of ampoule life condition has not been met; and

calculate the new set of temperature setpoints to be applied to the ampoule based upon the conservative ΔT.