Integrated wafer bow measurements

1. A wafer bow measurement system comprising:

a measurement unit including:

a wafer support assembly to impart rotational movement to a measured wafer supported in the measurement unit;

an optical sensor;

a calibration standard to calibrate the optical sensor;

a linear stage actuator to impart linear direction of movement to the optical sensor;

a wafer centering sensor to determine a centering of the measured wafer supported in the measurement unit; and

a wafer alignment sensor to determine an alignment of the measured wafer supported in the measurement unit.

2. The wafer bow measurement system of claim 1 , wherein the water centering sensor includes an actuator for active centering of the measured wafer supported in the measurement unit.

3. The wafer bow measurement system of claim 1 , wherein the wafer support assembly includes a wafer alignment chuck.

4. The wafer bow measurement system of claim 1 , further comprising a reference wafer unit.

5. The wafer bow measurement system of claim 4 , wherein the reference wafer unit includes a plurality of slots to accommodate a series of different reference wafers.

6. The wafer bow measurement system of claim 5 , wherein the series of different reference wafers provide a range of measurement control references for the measured wafer supported in the measurement unit.

7. The wafer bow measurement system of claim 5 , wherein the wafer bow measurement system further comprises a temperature sensor or a humidity sensor, and wherein a selection of a reference wafer in the series of different reference wafers is based on data derived from the temperature sensor or the humidity sensor.

8. The wafer bow measurement system of claim 4 , further comprising a plurality of measurement units and at least one reference wafer unit.

9. The wafer bow measurement system of claim 1 , wherein the water bow measurement system is integrated with a wafer processing tool.

10. The wafer bow measurement system of claim 1 , wherein the calibration standard includes at least one premeasured feature or facet scannable by the optical sensor to detect a stray in wafer bow measurement over time.

11. The wafer bow measurement system of claim 10 , wherein the scannable feature or facet includes a wedge shaped silver coated diffused optical flat to serve as a proxy for a wafer thickness.

12. The wafer bow measurement system of claim 1 , wherein the calibration standard includes multiple steps scannable by the optical sensor to detect a stray in wafer bow measurement over time.

13. The wafer bow measurement system of claim 1 , further comprising a vibration isolation mechanism or mount.

14. A method of measuring a water bow of a wafer in a wafer processing stream that includes a wafer processing module, the method comprising:

integrating a wafer bow measurement system with the wafer processing module, the wafer measurement system comprising:

a wafer support assembly to impart rotational movement to a measured wafer supported in the measurement unit;

an optical sensor;

a calibration standard to calibrate the optical sensor;

a linear stage actuator to impart linear direction of movement to the optical sensor;

a wafer centering sensor to determine a centering of the measured wafer supported in the measurement unit; and

a wafer alignment sensor to determine an alignment of the measured wafer supported in the measurement unit;

extracting a wafer from the wafer processing stream for wafer bow measurement by the wafer bow measurement system;

adjusting a parameter of the wafer processing stream based on a water bow measurement derived by the wafer bow measurement system; and

placing the measured wafer back into the wafer processing stream.