1. A method of configuring a signal for controlling a voice coil motor (VCM), said method comprising:
accessing a voltage at an error amplifier of a VCM driver;
accessing a target value at said error amplifier;
determining a difference value between said target value and said voltage; and
adjusting an impedance value of a variable compensation based on said difference value, wherein said variable compensation is coupled with said error amplifier.
2. The method of claim 1, further comprising:
adjusting said impedance value of a variable compensation according to a mode of a VCM driver operation.
3. The method of claim 1, further comprising:
adjusting said impedance value of a variable compensation according to a mode of a VCM operating environment.
4. The method of claim 1, wherein said determining a difference value between said target value and said voltage further comprises:
accessing said target value at a digital-to-analog converter.
5. The method of claim 1, wherein said adjusting an impedance value of a variable compensation coupled with said error amplifier based on said difference value further comprises:
providing a variable resistor in series with a fixed resistor andor a capacitor.
6. The method of claim 1, wherein said adjusting an impedance value of a variable compensation coupled with said error amplifier based on said difference value further comprises:
providing a variable capacitor in parallel with a fixed capacitor which in turn is in series with a fixed resistor.
7. The method of claim 1, wherein said adjusting an impedance value of a variable compensation coupled with said error amplifier based on said difference value further comprises:
providing a network of variable capacitance in series with a network of variable resistance.
8. The method of claim 2, further comprising:
modifying a bandwidth according to said mode of a VCM driver operation.
9. The method of claim 8, further comprising:
increasing a value of said variable impedance to obtain a higher magnitude response with a reduced phase loss.
10. The method of claim 8, further comprising:
decreasing a value of said variable impedance to obtain a lower magnitude response with an increased phase loss.
11. An adjustable voice coil motor (VCM) driver for configuring a signal for controlling a VCM, said adjustable VCM driver comprising:
a voltage accessor configured to access a voltage at an error amplifier of a VCM driver;
a target value accessor configured to access a target value at said error amplifier;
a difference value determiner configured to determine a difference value between said target value and said voltage; and
a compensation value adjuster configured to adjust an impedance value of a variable compensation based on said difference value, wherein said variable compensation is coupled with said error amplifier.
12. The system of claim 11, further comprising:
a fixed resistor andor a capacitor in series with said variable compensation.
13. The system of claim 11, further comprising:
a fixed resistor and a capacitor, said capacitor in parallel with said variable compensation.
14. The system of claim 11, further comprising:
a network of variable capacitance in series with a network of variable resistance
15. The system of claim 11, wherein said compensation value adjuster further comprises:
a VCM driver operation mode adjuster configured to adjust said impedance value of said variable compensation according to a mode of a VCM driver operation.
16. The system of claim 11, wherein said compensation value adjuster further comprises:
a VCM operating environment mode adjuster configured to adjust said impedance value of said variable compensation according to a mode of a VCM operating environment.
17. The system of claim 15, wherein said VCM driver operation mode adjuster further comprises:
a bandwidth modifier configured for modifying a bandwidth according to a VCM driver operation mode.
18. The system claim 17, wherein said bandwidth modifier further comprises:
a value increaser configured for increasing a value of said variable impedance to obtain a higher magnitude response with a reduced phase loss.
19. The system of claim 18, wherein said bandwidth modifier further comprises:
a value decreaser configured for decreasing a value of said variable resistor to obtain a lower magnitude response with an increased phase loss.
19. The system of claim 16, wherein said VCM operating environment mode adjuster further comprises:
a temperature sensor reader configured to read a temperature sensor and make corresponding adjustments to said internal variable compensation.
20. A hard disk drive comprising:
a housing;
at least one disk mounted to the housing and rotatable relative to the housing;
an actuator mounted to said housing and being movable relative to said at least one disk, said actuator having a suspension for reaching over said at least one disk, said suspension having a slider coupled therewith, said slider having a readwrite head element; and
a variable compensation configured for adjusting an impedance value of said variable compensation based on a difference value between a voltage accessed at an error amplifier of a voice coil motor (VCM) driver and a target value accessed at said error amplifier, wherein said variable compensation is coupled with said error amplifier.
21. The hard disk drive of claim 20, wherein said variable compensation further comprises:
a VCM driver operation mode adjuster configured to adjust said impedance value of a variable compensation according to a mode of a VCM driver operation.
22. The hard disk drive of claim 20, wherein said VCM driver operation mode adjuster further comprises:
a bandwidth modifier configured for modifying a bandwidth according to a VCM driver operation mode.
23. The hard disk drive of claim 20, wherein said variable compensation further comprises:
a VCM operating environment mode adjuster configured to adjust said impedance value of a variable compensation according to a mode of a VCM operating environment.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method for inline monitoring of a device’s pattern profile, comprising:
forming a patterned layer on a wafer, wherein the wafer comprises several dies;
depositing an insulator on the patterned layer; and
comparing the difference of the insulator in nearby dies in corresponding local areas.
2. The method as claimed in claim 1, wherein the insulator is a silicon oxide layer.
3. The method as claimed in claim 1, further comprising the following steps:
depositing the insulator by high density plasma chemical vapor deposition.
4. The method as claimed in claim 1, wherein the thickness of the insulator is to 1.5 times the height of the patterned layer.
5. A method for inline monitoring of a device’s pattern profile, comprising:
forming a patterned layer on a wafer, wherein the wafer comprises several dies;
depositing an insulator on the patterned layer by high density plasma chemical vapor deposition; and
comparing the height difference of the insulator in nearby dies in corresponding local areas.
6. The method as claimed in claim 5, wherein the insulator is a silicon oxide layer.
7. The method as claimed in claim 5, wherein the thickness of the insulator is to 1.5 times the height of the patterned layer.
8. The method as claimed in claim 5, wherein the comparing step is conducted based on the difference of reflection and refraction.
9. The method as claimed in claim 5, wherein the comparing step is conducted by a defect measurement device.
10. The method as claimed in claim 5, wherein the comparing step is conducted by a refraction measurement device.