NanoPWM Drives
for
High Performance
Positioning Applications
Ze’ev Kirshenboim
ACS Motion Control
Market Need
Wafer Inspection
Wafer Inspection – 300mm wafers
> Positioning performance
>
Standstill jitter < 1 Nanometer
>
Smooth constant velocity - ±3nm following error @ <
100mm/sec.
> Next generation of 450 mm wafers
2
>
Similar and better positioning performance
>
Much higher power due to size
>
Bus voltage > 100Vdc,
Preferred: 160Vdc, 320Vdc
>
Motor phase current > 30A peak
Market Needs
OLED FPD Inspection
> Positioning performance
> Standstill jitter < 5 Nanometer
> Smooth constant velocity
±10nm following error @ 100mm/sec.
> High power due to size
> Bus voltage > 320Vdc
> Motor phase current > 30A peak
3
Market Needs
High Performance Positioning
Linear Air Bearing Stages
Air bearing spindles
Linear Servo Stages
Lens Grinding Equipment
Laser Steering
Ultrasonic Scanning
Coordinate Measuring Machines (CMM)
4
Present Drive Solutions
Linear Servo Drives
Using Linear Servo Drives due to:
> Low noise
> High bandwidth
> Zero crossover distortion (linearity)
> No current ripple
5
Present Drive Solutions
Linear Servo Drives
Linear servo drives drawbacks
>
>
>
>
Low efficiency, high heat dissipation
Large size
Difficult / expensive fault protection
Complex supply requirements
>
+/-15vdc Bias Supply
>
Two (+/-) DC Motor Bus Supplies
> Analog current loop tuning requires changing components
> Available products are limited in voltage (<150Vdc)
> Expensive
6
Present Drive Solutions
Switching PWM Drives
PWM Servo Drives advantages
>
>
>
>
High efficiency, low heat dissipation
Compact size
Excellent fault protection
Simple supply requirements
> Single Motor Bus Supply
> High voltage and current
> Low(er) cost
7
Present Drive Solutions
Switching PWM Drives
PWM servo drives drawbacks
>
>
>
>
High switching noise
Cross over distortion (non-linearity)
Current ripple
10,11 bits current dynamic range free of noise
Until now, PWM servo drives were not used in demanding
application with nanometers level jitter and following errors
8
The Goal
Combining the advantages of Linear & PWM drives
Low noise
High bandwidth
Zero crossover
distortion
Low current ripple
High efficiency
9
Simple supply
High voltages &
currents
Digital current control
Compact
Cost effective
NanoPWMTM Drives
Better Than Linear Drives
Replaces linear drives
It is a PWM drive
> 15, 16 bits dynamic range free of noise
>
>
>
>
10
Better performance
Sub-nanometer jitter
Smoother velocity, lower tracking error
Higher voltages, higher currents
NanoPWMTM Drives
Better than Linear Drives
Linear drive
+/‐50V, 6/30A
>
>
>
>
A much smaller package
Better reliability
Fully digital control
Simpler power supply
requirements
> Better price
NanoPWMdrive
320V, 15/30A
11
NanoPWMTM
Two Lines of Drives
> NPM
> EtherCAT slaves – Similar to other ACS’ drive modules
> Expanding the line of ACS’ EtherCAT drives
> NPD
> Drive with ±10V current commutation commands
> Direct replacement for linear drives
12
ACS Motion Controller
EtherCAT
NanoPWM
Drive
M
E
Direct replacement to Linear drive Any Motion Controller
+/‐10V
NanoPWM
Drive
M
E
NPM / NPD
Three Form Factors
Chip like
Bookshelf, panel mounted
Rack mounted
13
NPM / NPD 100Vdc drives
Main Specifications (per axis/motor)
Max Voltage [Vdc]
Cont
Current [A]
Peak current [A]
Cont Power [W}
Peak Power [W]
100
3.3
10
340
950
100
6.6
20
680
1900
100
10
30
1,020
2850
100
13.3
40
1,380
3,800
For wafer inspection & metrology, optical lenses processing
> Standstill Jitter <1nm
> Following error at constant velocity < 3nm
14
MC4U 320Vdc
Main Specifications Max Voltage [Vdc]
Cont
Current [A]
Peak current [A]
Cont Power [W}
Peak Power [W]
100
15
30
1,300
2,600
320
15
30
4,200
8,400
320V ‐ For large stages, such as FPD measurement
> Jitter <5nm
> Following error at constant velocity < 10nm
15
NanoPWM™
Performance Tests Examples
>
>
>
Test system: a linear stage, ironless motor, cross roller bearings, 0.4um Laser encoder
Sub‐nanometer position jitter
Nanometer stepping:
±0.4nm jitter
1nm steps
16
NanoPWM VS Linear Drive
Stand Still Jitter
NanoPWM
Linear Drive
Standstill jitter [nm] p‐p 0.8
3.6
Standstill jitter [nm] Std. Dev.
0.1
0.44
17
NanoPWM Drive
Wafer inspection Gantry Table, Standstill Jitter
Gantry Axis
(X0,X1)
Cross Axis
(Y)
Standstill jitter [nm] p‐p
0.6
1.4
Standstill jitter [nm] Std. Dev.
0.08
0.18
NanoPWM Drive
Wafer inspection Gantry Table, Move & Settle
300mm Wafer inspection stage
15Kg load
Move ‐ 25mm
Acceleration – 2g
Theoretical move time – 80ms
Settling window [nm]
Move & Settle [ms]
100
90
2
137
1
197
0.5
240
Fraunhofer IPT Tests
Air bearing stage
48Vdc supply
100nm steps
ACS Linear Drive
PWM Drive
Non‐ACS
NanoPWM
Drive
50nm steps
ACS Linear Drive
PWM Drive
Non‐ACS
NanoPWM
Drive
20nm steps
ACS Linear Drive
PWM Drive
Non‐ACS
NanoPWM
Drive
10nm steps
ACS Linear Drive
PWM Drive
Non‐ACS
NanoPWM
Drive
5nm steps
ACS Linear Drive
PWM Drive
Non‐ACS
NanoPWM
Drive
2nm steps
ACS Linear Drive
PWM Drive
Non‐ACS
NanoPWM
Drive
1nm steps
ACS Linear Drive
PWM Drive
Non‐ACS
NanoPWM
Drive
2nm Steps, Mechanical Bearing Stage
> Step size – 2nm
> standstill jitter ‐ ±0.25nm Constant Velocity Smoothness
> Constant velocity – 100um/sec
> Following error < ±2nm NanoPWM™
Better Drive. Smarter Motion.
NanoPWMTM
30
Linear drive
PWM
Performance
Excellent
Very Good
Not suitable
Complexity
Low
High
Low
Package size
Small
Big
Small
Reliability
Excellent
Problematic
Excellent
Price
Medium
High
Low
THANK YOU