High Stability Plane Mirror Interferometer
Contents
1. The alignment should be adjusted such that the voltage reading from the receiver test point occurs just below the sudden jump up in voltage If the alignment is fixed to sustain this peaked voltage system operation will be degraded This aligns the laser beam to within 41 2 arc minutes of the direction of travel resulting in a cosine error of approximately 0 05 ppm 0 05 micron per meter of travel or 0 05 microinch per inch Fasten the interferometer X axis securely making sure the alignment is not disturbed Remove the alignment aid Agilent Part Number 10706 60001 from the interferometer Also remove the plane mirror converter from the interferometer Switch to the small aperture on the laser head Block the measurement beam by placing something between the interferometer and the measurement mirror Insert Agilent 10706B alignment aid Agilent Part Number 10706 60202 between the beam splitter and the high stability adapter as shown in Figure 7D 5 This allows the reference beam to be autoreflected from the high stability adapter back toward the small aperture of the laser head Observe the reflection of the reference beam back at the laser head Adjust two of the four adjustment screws until the beam autoreflects into the small aperture of the laser head Once autoreflection is achieved gently snug the two remaining set screws Be careful to preserve the autoreflection alignment Remove the Agilent 10706B interferometer align2. 20 inches between the laser and mirror perform steps 5 through 7 Remove the plane mirror interferometer alignment target and select the large aperture of the laser head Do not remove the plane mirror interferometer alignment aid on the output side of the plane mirror interferometer Center the output beams on the receiver aperture by moving the receiver side to side Translucent tape over the receiver aperture will help you observe when the beams are centered Connect a fast responding voltmeter preferably an analog type to the Y Axis receiver test point Pitch and yaw the interferometer until a signal is received This is indicated by the voltmeter suddenly jumping to a value greater than 0 25 volt This adjustment is a critical and may require great care to achieve the desired result Adjust the voltmeter reading which may be fluctuating for a maximum by pitching and yawing the interferometer Carefully readjust the interferometer until the voltage reading suddenly drops back to about 0 3 volt The alignment should be adjusted such that the voltage reading from the receiver test point occurs just below the sudden jump up in voltage If the alignment is fixed to sustain this peaked voltage system operation will be degraded This aligns the laser beam to within 1 2 arc minutes to the direction of travel resulting in a cosine error of approximately 0 05 ppm 0 05 micron per meter of travel or 0 05 microinch per inch Fasten the
3. 60202 Figure 7D 4 Agilent 10706B Interferometer alignment aids 7D 8 User s Manual Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration Using the Alignment Aid Figure 7D 5 Using the Agilent 10706 60202 Alignment Aid Alignment Procedures Two alignment procedures are given for the Agilent 10706B High Stability Plane Mirror Interferometer e thestraight through configuration as shipped in a single axis application e theturned configuration for two axis X Y stage applications Straight Through Configuration Signal Axis Alignment This procedure describes the alignment of the Agilent 10706B High Stability Plane Mirror Interferometer used in the straight through configuration Before proceeding review Alignment Principles in Chapter 4 System Installation and Alignment of this manual This procedure minimizes cosine error and the thermal drift coefficient of the Agilent 10706B interferometer and maximizes signal strength at the receiver Two separate autoreflection adjustment steps are performed using the two alignment aids Movethestage toits point furthest from the laser head Align the laser beam perpendicular to the measurement mirror by autoreflection Position the Agilent 10706B interferometer in the beam path between the laser head and the measurement mirror User s Manual 7D 9 NOTE NOTE Chapter 7D Agilent 10706B High Stability Plane Mirror Int
4. cosine error and the thermal drift coefficient of the Agilent 10706B interferometer and maximizes the signal at the receiver Two separate autoreflection adjustment steps are performed using the two alignment aids Steps 1 through 17 constitute the Y axis alignment Send the beam through the center of the 50 beam splitter Align the Y Axis laser beam parallel to the plane of the stage and measurement mirror by pitching and yawing the laser head and moving it side to side This ensures that the interferometer turns the beam 90 Using an optical square or pentaprism is helpful Secure the laser head 7D 12 User s Manual Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration X Y STAGE APPLICATION High Stability Plane Mirror Adapter Converter X Y STAGE X Axis Agilent 10706B X Y MIRRORS Laser Beam Ey A Plane Mirror i Alignment Aid A Converter W P N 10706 60001 Y Axis Laser Beam X Axis Receiver Y Axis Agilent 10706B Receiver Alignment Target High Stability P N 10702 60001 Adapter Figure 7D 6 Agilent 10706B High Stability Plane Mirror Interferometer in an X Y Stage Application 2 Position the Agilent 10706B interferometer in the beam path to turn the beam 90 toward the measurement mirror Place the alignment target Agilent Part Number 10702 60001 on the input side of the interferometer Place the alignment aid Agilent Part Number 10706
5. interferometer Y Axis securely preserving the alignment 7D 14 User s Manual 10 11 12 16 17 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration Remove the alignment aid Agilent Part Number 10706 60001 from the interferometer Also remove the plane mirror converter from the interferometer Switch to the small aperture on the laser head Block the measurement beam by placing something between the Y Axis interferometer and the measurement mirror Insert Agilent 10706B interferometer alignment aid Agilent Part Number 10706 60202 between the beam splitter and the high stability adapter as shown in Figure 7D 5 This allows the reference beam to be autoreflected from the high stability adapter back toward the small aperture of the laser head Observe the reflection of the reference beam back at the laser head Adjust two of the four alignment set screws until the beam autoreflects into the small aperture of the laser head Once autoreflection is achieved gently snug the two remaining set screws Be careful to preserve the autoreflection alignment Remove the Agilent 10706B interferometer alignment aid Agilent Part Number 10706 60202 between the beam splitter and the high stability adapter Replace the plane mirror converter removed in step 9 Remove the beam block from between the interferometer and the measurement mirror The reference and measurement beams must be centered on
6. ou can see this difference by comparing the laser path drawings for the two interferometers In addition to the material presented in this subchapter you should also read about the Agilent 10706A interferometer in subchapter 7C of this manual Laser beam paths Figure 7D 2 shows the optical schematic for the Agilent 10706B High Stability Plane Mirror Interferometer Note that the usual reference beam cube corner see the Agilent 10706A laser beam path schematic in subchapter 7C of this manual has been replaced with a quarter wave plate with a high reflectance coating on the back In this configuration the measurement and reference beams have the same optical path length through glass which virtually eliminates measurement errors due to the temperature changes in the optic The remaining thermal errors are due to mechanical tolerances in the geometry of the device Typically the Agilent 10706B exhibits drift of 0 04 micron per degree C of optics temperature change 7D 2 User s Manual Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Description Turned Configuration Straight Through Configuration Agilent 10706B High Stability Plane Mirror Interferometer Figure 7D 1 Agilent 10706B High Stability Plane Mirror Interferometer User s Manual 7D 3 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer A l tatar Description MEASUREMENT PATH f Quarter wave SU fa Hi
7. the laser and or the beam steering optics securely taking care not to disturb the alignment For high accuracy alignment or for installations where there is less than 0 5 meter 20 inches between the laser and mirror perform steps 6 through 8 Remove the alignment target Agilent Part Number 10702 60001 and select the large aperture of the laser head Do not remove the alignment aid Agilent Part Number 10706 60001 on the output side of the interferometer Center the output beams on the receiver aperture by moving the receiver Translucent tape over the receiver aperture will help to observe when the beam is centered Connect a fast responding voltmeter preferably an analog type to the receiver test point Pitch and yaw the laser beam until a signal is received This is indicated by the voltmeter suddenly jumping toa value greater than 0 25 volt This adjustment is critical and may require great care to achieve the desired result 7D 10 User s Manual NOTE 10 11 12 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration Pitch and yaw the laser beam to achieve maximum voltmeter reading Carefully readjust the interferometer until the voltage reading suddenly drops back to about 0 3 volt The alignment should be adjusted such that the voltage reading from the receiver test point occurs just below the sudden jump up in voltage If the alignment is fixed to sustain this peaked voltage sy
8. turns the beam 90 degrees Using an optical square or pentaprism is helpful Secure the 50 beam splitter Place the Agilent 10706B interferometer in the beam path to turn the beam 90 degrees toward the measurement mirror Place the alignment target Agilent Part Number 10702 60001 on the laser input side of the interferometer Place the alignment aid Agilent Part Number 10706 60001 on the output side of the interferometer in the correct orientation the hole allows transmission of the primary measurement beam Select the small aperture on the front turret of the laser head Move the interferometer side to side until the beam 1 passes through the center of one hole on the alignment target 2 passes through the hole on the alignment aid Agilent Part Number 10706 60001 and 3 strikes the measurement mirror Use translucent tape over the aperture of the alignment target to observe centering of the beam If the distance between the laser head and the reflector is greater than 0 5 meter 20 inches the formula given in the Overlapping Dots Method Summary section of Chapter 4 determines the cosine error based on the offset of the return beam at the laser head For example with a distance between the laser head and reflector of 0 5 meter and an offset of the return beam at the small aperture of the laser of 500 microns 0 0202 inch the cosine error is approximately 0 12 ppm Pitch and yaw the interferometer until the beam reflecte
9. 4 ounces Flatness Depending on the application and accuracy Dimensions see figure below requirements of the application mirror flatness may Materials Used range from A 4 to 4 20 i e 0 16 to 0 03 umeters 6 to Housing Stainless Steel 1 2 pinches Apertures Plastic Nylon NOTE Flatness deviations will appear as measurement errors Spacers Plastic Nylon when the mirror is translated across the beam Mount should be Optics Optical Grade Glass kinematic so as not to bend mirror If accuracy requirements Adhesives Low Volatility Vacuum Grade demand it mirror flatness might be calibrated scanned and Optical Efficiency stored in the system controller to be used as a correction Typical 60 factor Worst Case Calculated 43 Optical Surface Quality 60 40 per MIL 0 13830 Thermal Drift Coefficient Change of indicated distance per degree C Measurement or Reference Mirror Pitch Yaw temperature change 0 04 micron C 1 6 pinch C typical Depends on distance between interferometer and plane mirror Typical mirror pitch yaw angles are Fundamental Optical Resolution 4 6 arc minutes for 152mm 6 inches Non linearity Error lt 2 2 nm 0 09 pin 3 arc minutes for 305 mm 12 inches PLANE MIRROR MEASUREMENT MIRROR RECOMMENDATIONS 1 5 arc minutes for 508 mm 20 inches Reflectance 98 for 633 nanometers at normal incidence Misalignment of interferometer to measurement mirror minimum 80 will degrade the Thermal Drift Coef
10. 60001 on the output side of the interferometer in the correct orientation the hole allows transmission of the primary measurement beam Select the small aperture on the laser head turret 3 Movethe interferometer side to side until the beam 1 passes through the center of one hole on the alignment target 2 through the hole on the alignment aid and 3 strikes the measurement mirror Use translucent tape over the target aperture to observe when the beam is centered User s Manual 7D 13 NOTE NOTE NOTE Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration If the distance between the laser head and the reflector is greater than 0 5 meter 20 inches the formula given in the Overlapping Dots Method Summary section of Chapter 4 determines the cosine error based on the offset of the return beam at the laser head For example with a distance between the laser head and reflector of 0 5 meter and an offset of the return beam at the small aperture of the laser of 500 microns 0 0202 inch the cosine error is approximately 0 12 ppm Pitch and yaw the interferometer until the beam reflected from the measurement mirror returns upon itself through the interferometer and back to the small aperture of the laser head Once this autoreflection is achieved secure the interferometer while preserving the alignment For high accuracy alignment or for installations where there is less then 0 5 meter
11. 7D Agilent 10706B High Stability Plane Mirror Interferometer Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Description Description The Agilent 10706B High Stability Plane Mirror Interferometer see Figure 7D 1 is an improved version of the Agilent 10706A interferometer It offers very high thermal stability Its thermal drift is typically 1 12 that of a conventional plane mirror interferometer The Agilent 10706B High Stability Plane Mirror Interferometer uses plane mirror reflectors For X Y stage applications the user must provide the mirror s Using plane mirror reflectors allows for a marked improvement in measurement stability thereby reducing the designer s error budget Existing system designs can be easily upgraded since the Agilent 10706B interferometer is an exact functional replacement for the Agilent 10706A interferometer and is the same size and weight It can be used in the same applications as the Agilent 10706A interferometer but requires different alignment techniques See the Alignment section later in this subchapter for alignment procedures Externally and in its use the Agilent 10706B interferometer is identical to the Agilent 10706A Plane Mirror Interferometer described in the previous subchapter subchapter 7C Internally however the design and configuration of the Agilent 10706B interferometer s optical elements differs from that of the Agilent 10706A interferometer Y
12. d from the measurement mirror returns upon itself through the interferometer and back to the small aperture of the laser head Once autoreflection is achieved secure the interferometer preserving the alignment For high accuracy alignment or for installation where there is less than 0 5 meter 20 inches between the laser and mirror perform steps 22 through 24 Remove the alignment target Agilent Part Number 10702 60001 and rotate the turret of the laser head to select the large aperture Do not remove the alignment aid Agilent Part Number 10706 60001 on the output side of the interferometer Center the output beams on the receiver aperture by moving the receiver side to side Translucent tape over the receiver aperture will help you observe when the beam is centered 7D 16 User s Manual NOTE 23 25 26 27 28 29 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration Connect a fast responding voltmeter to the receiver test point Pitch and yaw the plane mirror interferometer until a signal is received at the receiver The voltmeter will suddenly jump to some value greater than 0 25 volt This adjustment is critical and may require great care to achieve the desired result Pitch and yaw the interferometer until the voltmeter reading which may be fluctuating is maximum Carefully readjust the interferometer until the voltage reading suddenly drops back down to about 0 3 volt
13. ent 10706B High Stability Plane Mirror Interferometer Specifications and Characteristics Specifications and Characteristics Specifications describe the device s warranted performance Supplemental characteristics indicated by TYPICAL or NOMINAL are intended to provide non warranted performance information useful in applying the device Plane mirror systems have a fundamental optical resolution of one quarter wavelength 0 158 micron 6 23 microinches Using electronic resolution extension the system resolution is increased significantly Depending on the system an additional resolution extension factor of 32 for Agilent 10885A and 10895A or 256 for Agilent 10897B and 10898A is usually available Interferometer Fundamental Optical System Resolution 1 System Resolution 2 Resolution see NOTE see NOTE Agilent 10706B 1 4 158 2 nm 6 2 pin 1 128 5 0 nm 0 2 pin 4 1024 0 62 nm 0 024 pin NOTE The system resolution 1 is based on using 32X electronic resolution extension This is available with the Agilent 10885A and Agilent 10895A electronics The system resolution 2 is based on using 256X electronic resolution extension This is available with the Agilent 10897B and Agilent 10898A electronics User s Manual 7D 19 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Specifications and Characteristics Agilent 10706B Plane Mirror Interferometer Specifications Weight 323 grams 11
14. erferometer Turned Configuration Place the interferometer alignment target Agilent Part Number 10702 60001 on the laser input side of the interferometer Place the alignment aid Agilent Part Number 10706 60001 on the outside side of the interferometer in the correct orientation the hole allows transmission of the primary measurement beam Select the small aperture on the front turret of the laser head Move the interferometer until the beam passes 1 through the center of one hole on the alignment target 2 through the hole on the alignment aid and 3 strikes the measurement mirror Use translucent tape over the target aperture to observe when the beam is centered If the distance between the laser head and the reflector is greater than 0 5 meter 20 inches the formula given in the Overlapping Dots Method Summary section of Chapter 4 determines the cosine error based on the offset of the return beam at the laser head For example with a distance between the laser head and reflector of 0 5 meter and an offset of the return beam at the small aperture of the laser of 500 microns 0 0202 inch the cosine error is approximately 0 12 ppm Pitch and yaw the laser beam until the beam reflected from the measurement mirror returns upon itself through the interferometer and back to the small aperture of the laser head Move the laser head or the interferometer to keep the laser beam centered on one hole of the alignment target Fasten
15. ficient To Plane Mirror 12 7 mm From Laser 0 50 Beam Spacing A z Q O To Receiver 28 5 mm BE 1 12 14mm 0 55 l t 53 mm 38 1mm al 2 09 32 mm 76mm 1 50 1 26 2 99 h ie Oo DT y 33 3 mm i 1 31 Aperture 20 8 mm Dia 4x Drilled For Clearance 38 1 0 82 Of 4 40 Screw and Tapped as i He 6 32 UNC 2B x 250 Deep 1 50 4x This Side and 4x Far Side Figure 7D 7 Agilent 10706B Plane Mirror Interferometer dimensions 7D 20 User s Manual Product specifications and descriptions in this Laser and Optics User s Manual document subject to change without notice For complete manual order Copyright C 2002 Agilent Technologies Paper version p n 05517 90045 Printed in U S A 07 02 CD version p n 05517 90063 This is a chapter from the manual titled This chapter is p n 05517 90111
16. g and adjusting hardware is contained in a bag shipped with the Agilent 10706B interferometer Using the hex key provided install the four 2 56 x 3 16 inch long screws into the holes on the flange of the High Stability Adapter housing Be sure that they do not protrude through the flange Equip both 4 40 x 1 2 inch long mounting screws with a compression spring and use them to mount the High Stability Adapter in place of the plane mirror converter as shown in Figure 7D 3 7D 6 User s Manual Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration Agilent 10706B High Stability Plane Mirror Interferometer Conversion Using the Agilent 10723A High Stability Adapter A A Agilent 10723A High Stability y y Plane Mirror Adapter se Agilent 10723A converter High Stability Adapter Plane Mirror Converter a aE lt Ko gt M Cube Corner H Cube Corner Straight through Configuration Turned Configuration Figure 7D 3 Agilent 10706B Interferometer configurations 3 Tighten both mounting screws until the head of each just begins to compress the spring Then tighten each screw two turns to properly compress each spring NOTE Changing to the turned configuration changes the measurement direction sense see the Effect of Optics on M easurement Direction Sense section of Chapter 3 System Design Considerations of this manual If the High Stability Adapter is
17. gh Reflector Plates Y X fa fatAt fa gt A 7 W fat 2Af fat2Af ty tAf N SX Agilent 10706B High Stability Plane Mirror Interferometer Measurement Mirror REFERENCE PATH fp High Reflector Quarter wave iat fp i A D m m po a ae al Agilent 10706B High Stability Plane Mirror Interferometer Measurement Mirror COMPOSITE faq and fp High Reflector Quarter wave ae Plates Ate gt fat at 4 fat24f fB J I fyt2at fa Af ws y A v 1 4 Pa fat Af Agilent 10706B High Stability Plane Mirror Interferometer Measurement Mirror LEGEND lt gt fp me p g gt fand fg f r Rounded corners are used to help you trace paths Figure 7D 2 Agilent 10706B High Stability Plane Mirror Interferometer optical schematic 7D 4 User s Manual Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Special Considerations Special Considerations See the Agilent 10706A Special Considerations information in subchapter 7C of this manual Mounting Adjustable mounts The Agilent 10711A Adjustable Mount provides a convenient means of mounting aligning and securely locking the Agilent 10706B interferometer in position Since the mount allows some tilt and yaw adjustment the need for custom fixturing is minimized The mount allows the interferometer to be rotated about its centerline simplifying installation Fasteners The Agilent 10706B interferometer
18. installed in the wrong location the interferometer will have worse thermal stability User s Manual 7D 7 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration Alignment aids The Agilent 10706B High Stability Plane Mirror Interferometer is supplied with the alignment aids shown in Figure 7D 4 e Alignment Aid Agilent Part Number 10706 60001 e Alignment Target Agilent Part Number 10702 60001 e Alignment Aid Agilent Part Number 10706 60202 The first two of these alignment aids are the same as those used on the Agilent 10706A Plane Mirror Interferometer Refer to the Alignment Aids for the Agilent 10706A Plane Mirror Interferometer in subchapter 7C for a further discussion of their use Alignment Aid Agilent Part Number 10706 60202 facilitates autoreflection alignment for the high stability adapter to achieve minimal thermal drift It contains a quarter wave plate to reflect the reference beam back on itself and return it to the laser head without offset Figure 7D 5 illustrates how the aid is positioned between the beam splitter and the high stability adapter during alignment Alignment Aid Insert between Beam Splitter and High Stability reflector ee gees during autoreflection REMOVE TA RGET Ee Ag i l ent AFTER A LIGNING Agilent Technolo gies P N 10706 60202 ben er ee Agilent Tec Agilent Target Agilent Aid Agilent Aid P N 10702 60001 P N 10706 60001 P N 10706
19. is supplied with English mounting hardware which is required to fasten it to its adjustable mount Installation Refer to the Agilent 10706A interferometer Installation information in subchapter 7C of this manual Alignment The alignment procedure for the Agilent 10706B High Stability Plane Mirror Interferometer is similar to that for the Agilent 10706A except for an additional alignment of the High Stability Adapter The alignment procedure follows the instructions for reconfiguring the Agilent 10706B interferometer and using the alignment aids which begin below User s Manual 7D 5 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Straight Through Configuration Straight Through Configuration The Agilent 10706B High Stability Plane Mirror Interferometer is shipped in the straight through configuration as shown in Figure 7D 3 Note the location of the plane mirror converter and high stability adapter with respect to the graphics on the label Turned Configuration The Agilent 10706B interferometer can be configured to turn the beam to reduce the number of beam bending optics as shown in Figure 7D 3 This is done by interchanging the high stability adapter and the plane mirror converter and adding new mounting and adjusting hardware for the High Stability Adapter N ote the location of the plane mirror converter and high stability adapter with respect to the graphics on the label The new mountin
20. ment aid P N 10706 60202 from between the beam splitter and the high stability adapter Replace the plane mirror converter removed in step 26 above Remove the beam block from between the interferometer and the measurement mirror User s Manual 7D 17 31 32 33 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration The reference and measurement beams must be centered on the receiver aperture Using translucent tape over the receiver aperture to observe the beams move the receiver side to side to center the beams Place the interferometer alignment aid P N 10706 60001 back on the output side of the interferometer and switch to the large aperture on the laser head Connect a fast responding voltmeter to the receiver test point Monitor the voltage reading along the complete travel of the stage The voltage should not jump up to the previous maximum voltage reading If the voltage does jump readjust the interferometer as in step 21 until the voltage reading suddenly drops back to about 0 3 volt If readjustment of the interferometer is required in step 31 return to step 26 and repeat the procedure from that point Remove the interferometer alignment aid Rotate the turret on the laser head to the large aperture Verify that the LED indicator on the receiver is illuminated and the voltage at the receiver test point is between 0 6 and 1 3 volts DC 7D 18 User s Manual Chapter 7D Agil
21. pe over the receiver aperture to observe the beams Move the receiver side to side to center the beams on the receiver aperture Place the alignment aid Agilent Part Number 10706 60001 back on the output side of the interferometer and switch to the large aperture on the laser head Connect a fast responding voltmeter to the receiver test point Monitor the voltage reading along the complete travel of the stage The voltage should not jump up to the previously peaked voltage User s Manual 7D 11 NOTE 16 17 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration reading If the voltage does jump readjust the laser beam as in step 5 until the voltage reading suddenly drops back down to about 0 3 volt If readjustment of the laser head or beam steering optics is required in step 15 then return to step 9 and repeat the procedure Remove the interferometer alignment aid Rotate the turret on the laser head to the large aperture Verify that the LED indicator on the receiver is illuminated and the voltage at the receiver test point is between 0 6 and 1 3 volts DC Turned Configuration X Y Stage Example Alignment This procedure describes the alignment of Agilent 10706B interferometers used in an X Y stage application as shown in Figure 7D 6 Before proceeding review the Alignment Principles in Chapter 4 System Installation and Alignment of this manual This procedure minimizes
22. stem operation will be degraded This aligns the laser beam to within 1 2 arc minutes to the direction of travel resulting in a cosine error of approximately 0 05 ppm 0 05 microns per meter of travel or 0 05 microinch per inch Remove the alignment aid Agilent Part Number 10706 60001 from the interferometer Also remove the plane mirror converter from the interferometer Switch to the small aperture on the laser head Block the measurement beam by placing something between the interferometer and the measurement mirror Insert the Agilent 10706B interferometer alignment aid Agilent Part Number 10706 60202 between the beam splitter and the high stability adapter as shown in Figure 7D 5 This allows the reference beam to be autoreflected from the high stability adapter back toward the small aperture of the laser head Observe the reflection of the reference beam back at the laser head Pitch and yaw the interferometer until this reflection is returned back into the small aperture of the laser head Fasten the interferometer securely to preserve the pitch and yaw adjustments Remove the Agilent 10706B interferometer alignment aid Agilent Part Number 10706 60202 from between the beam splitter and the high stability adapter Replace the plane mirror converter Remove the beam block from between the interferometer and measurement mirror The reference and measurement beams must be centered on the receiver aperture Use translucent ta
23. the receiver aperture Use translucent tape over the receiver aperture to observe the beams Move the receiver side to side to center the beams on the receiver aperture Place the alignment aid Agilent Part Number 10706 60001 back on the output side of the interferometer and switch to the large aperture on the laser head Connect a fast responding voltmeter to the receiver test point Monitor the voltage reading along the complete travel of the stage The voltage should not jump up to the previous maximum voltage reading If the voltage does jump readjust the interferometer as in step 4 until the voltage reading suddenly drops back to about 0 3 volt If readjustment of the interferometer is required in step 14 return to step 9 and repeat the procedure from that point Remove the alignment aid Agilent Part Number 10706 60001 Rotate the turret on the laser head to the large aperture Verify that the LED indicator on the receiver is lighted and the voltage at the receiver test point is between 0 6 and 1 3 volts DC User s Manual 7D 15 NOTE NOTE NOTE 19 20 21 22 Chapter 7D Agilent 10706B High Stability Plane Mirror Interferometer Turned Configuration Steps 18 through 34 constitute the X axis alignment Align the X axis laser beam parallel to the plane of the stage and measurement mirror by adjusting the pitch and yaw of the 50 beam splitter do not adjust the laser head This ensures that the interferometer
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