KARL SUSS MJB3 UV400 Mask Aligner Standard Operating Procedure Version: 1.0 February 2014 UNIVERSITY OF TEXAS AT ARLINGTON Nanotechnology Research Center (NRC) 1
TABLE OF CONTENTS 1 Introduction 3 1.1 Scope of Work...3 1.2 Description..3 1.3 Safety Precautions... 4 2 Requirements.......5 2.1 Training... 5 2.2 Hardware,...5 2.3 Restrictions....... 5 3 Operating Procedure.........5 3.1 Lamp Powering Up Procedure.......5 3.2 Mask and Wafer Loading..8 3.3 Alignment and Setting Exposure Time.. 11 3.4 Shutdown Procedure...12 2
1 INTRODUCTION 1.1 Scope These procedures apply to the KARL SUSS MJB3 UV400 mask aligner. All maintenance should follow the procedures set forth in the manufacturer s maintenance and operations manuals. This document is for reference only. Personnel should be trained by authorized staff before operating MJB3 UV400 mask aligner. 1.2 Description The SUSS MJB3 UV400 mask aligner is designed for high resolution photolithography in a laboratory environment. The MJB3 mask aligner offers exceptional flexibility in the processing of irregular shaped samples of different thickness such as sample wafer pieces and glass slides up to standard size 2 diameter wafers. The SUSS MJB3 UV400 is equipped with 350W mercury short-arc lamp providing primary exposure wavelengths of 350-450nm. The machines equipped with a high precision stage allowing alignment accuracies to 0.25 microns. The resolution of the MJB3 UV400 is 1-2 microns under optimum conditions. 1.3 Safety Precautions 1.3.1 This equipment uses UV LIGHT SOURCE. Be very careful and aware of hazards that stem from the UV light source. The light emanating from the light source is a hazard to vision. DO NOT LOOK INTO THE OUTPUT BEAM of the UV Lamp or reflection of the beam. Permanent damage to the retina of the eye and subsequent blindness can result. If you encounter any hazards, contact NanoFAB staff immediately. 1.3.2 Prolonged exposure to diffused reflection from the output beam, illuminated surfaces in the beam, exposures of even a few seconds to the direct output beam or to the lamp itself, can cause ultraviolet skin burns or burns to the outer layers of the eye. 1.3.3 High voltage is used to run the UV lamp; do not attempt to disassemble supply 3
1.3.4 If the main lamp housing needs to be opened for service such and a stuck shutter the system that the light source is mounted on and the UV power supply should be powered down and locked out. Then the lamp N 2 cooling should be left on for 30 minutes to properly cool down the inside of the lamp housing before opening it for service. Call Nanofab staff for any maintenance issues. 1.3.5 This equipment uses a UV light source that is subjected to 20 to 30 atmospheres of internal pressure so there is always the possibility of a lamp exploding due to internal strains or physical abuse.. The lamp contains Mercury. Any vapor released by an exploded lamp would be highly dangerous. In the event of a lamp explosion, clear the area of personnel and contact the NanoFAB staff immediately. http://www.cdc.gov/niosh/npg/npgd0384.html http://www.sciencelab.com/msds.php?msdsid=9927224 1.3.6 Before changing the lamp, working on the light source, or performing any system maintenance requiring access to AC electrical power, Staff maintenance needs to turn OFF the power at the FACILITY AC POWER circuit breaker. After the power has been turned off, verify that the output voltage is zero. 1.3.7 Do not operate the system without proper room ventilation as some Deep UV lamps produce significant levels of OZONE. http://www.cdc.gov/niosh/topics/ozone/ http://www.ozoneapplications.com/info/ozone%20solutions%20msds%20ozone.pdf 1.3.8 Read any posted NanoFAB Engineering Change Notices (ECN) for any hardware, process or safety changes before running the tool. 4
2 REQUIREMENTS 2.1 Training You must be a qualified user on the SUSS MJB3 UV400 ALIGNER. 2.2 Hardware 2.2.1 High resolution contact exposure mode printing down to 1-2 um by using primary wavelengths of 350 to 450nm from a 350W mercury short-arc lamp. 2.2.2 High precision X, Y, and θ alignment stage and microscope manipulator. 2.2.3 Wafer, glass slides and substrate handling up to dia.50 mm (wafers), 1 x1 (substrates) 2.2.4 Special substrate chucks for pieces, III-V materials, thick substrates, hybrids. 2.2.5 Economical tool for laboratories and small series production. 2.3 Restrictions 2.3.1 Glass slides, small sample pieces up to 2 diameter wafer sizes can be aligned and exposed. Small sample pieces need to be fixed to a 2 carrier wafer. 2.3.2 Only 4 x 4 x (0.065-0.1 ) and 3 x 3 x (0.065-0.1 ) masks can be used. 2.3.3 MJB3 Aligner is available 7 days a week / 24 hours a day. 3 OPERATING PROCEDURE 3.1 Lamp Powering Up Procedure/ Mask and Wafer Loading/ Alignment and Exposure 3.1.1 The Hg-Arc lamp is peaked and calibrated to 3.0 mw/cm 2 with the UV probe. 3.1.2 Make sure the power to the aligner is OFF by checking the red Power button light is OFF. Turning ON the Illumination Controller when power to the aligner is ON, will damage the aligner. 5
3.1.3 Turn ON the lamp N 2 cooling switch to the up position. The N2 pressure should be 1.5 barr. 3.1.4 Turn on the green POWER switch on the Illumination Controller under the table by moving the lever to the up position then press the green Lamp button ( for nor more than 1 sec). The lamp should ignite. Press green channel button to toggle between sensor 1 and 2. Sensor 1 is 365nm sensor. Wait at least 10 minutes for the lamp to warm up, the display should read 275 W ( standby idle power on the lamp). 3.1.5 Turn the Aligner air pressure switch to the up position. The air pressure should be 2.0 barr. Check the mask vacuum switch is in the UP position (ON), if not move this switch to the up position. 3.1.6 Turn on the power to the aligner by pressing the red power button. 6
3.1.7 If you hear an alarm ( buzzer) sounding press the Nitrogen Loss button to silence the alarm (it was previously pressed by mistake) 3.1.8 Move the Contact Lever (1 st ) then the Separation Lever (2 nd ) to the separation position to before loading the mask or substrate. Contact Lever (1 st ) Separation Lever (2 nd ) 3.1.9 Loosen the Mask Holder clamping knobs by rotating both a few turns CCW, then slide the Mask holder OUT and place upside down on the table. 7
3.1.10 Carefully place your clean mask with the chrome side facing up (glass side in contact with the mask holder) on the mask holder. Make sure the mask is centered and its sides are perpendicular with the mask holder edges. Check to see if the masks die orientation is the correct orientation you need. Then press the Mask Vacuum button to turn ON mask vacuum. Check to see if the mask is holding with your wafer tweezers by gently tapping the mask edge. If you find a mask vacuum problem call staff to check ( to avoid a broken mask) 3.1.11 Carefully slide the mask + Mask Holder back into the mask guide rail and tightened the clamping knobs by turning them CW until they are finger tight. 3.1.12 Gently slide OUT the wafer holder tray and place you coated substrate on the chuck. Slowly slide the wafer holder tray and wafer all the way IN. 8
3.1.13 Move Separation Lever (1 st ) then the Contact Lever (2 nd ) to the Contact positions to remove any gap or wedge between the wafer and mask. The green contact light will go ON Separation Lever (1 st ) Contact Lever (2 nd t ) Green Contact light is ON 3.1.14 To aligne the substrate to the mask move the separation lever to the Separation position creating a gap. The green contact light will go OFF. 3.1.15 Turn on the Halogen lamp power supply to the Microscope illuminator to about 4 volts (middle of the scale). ON: Rotate dial CW direction to about 4 volts 3.1.16 Adjust the Microscope eyepiece for binocular vision, adjust the microscope manipulator for your field of view and use the focusing knobs to focus on the mask and die alignment markers. 9
3.1.17 Align your wafers alignment marks to the mask alignment marks by using X, Y, θ micrometers. 3.1.18 After the alignment is done move the Separation Lever back to the Contact position The green contact light should go ON. Contact Lever Green Contact light is ON 3.1.19 The substrate is now ready for exposure. Set the exposure time on the timer located at the right of the front panel. Your exposure time depends on the exposure Dose (mj /cm2) for your resist type and thickness and Lamp intensity (Mw/cm2). The exposure time is Dose Intensity. 3.1.20 To set the exposure time 1 st select the time units multiple (seconds, minutes, hours) by rotating the inner black knob to align with the black arrow to the time units multiple you need. Align with the black arrow to the time units you need ( ie. X 10s ) 10
3.1.21 Next rotate the Outer plastic dial the time base ( 0 to 3 ) you need. ( i.e. 2 X 10s) = 20 second exposure 3.1.22 The exposure time in now set. Press the blue Exposure button to expose the wafer. Turn away from the UV light, do not look at the UV light or you will damage your retinas permanently. 3.1.23 After the exposure is done move the Separation Lever (1 st ) then the Contact Lever (2 nd ) to the Seperation positions. The green contact light will go OFF. 3.1.24 Gently slide the wafer transport tray out and remove your wafer for further processing. 11
3.1.25 Loosen the Mask Holder clamping knobs by rotating both a few turns CCW, then slide the Mask holder OUT and place upside down on the table. Press the mask vacuum button to turn OFF mask vacuum and remove your mask. 3.1.26 After your mask is removed replace the mask holder and tightened the clamping knobs finger tight. 3.1.27 Turn OFF the microscope halogen illuminator power supply. 3.1.28 Turn OFF the Hg-Arc lamp power supply. 3.1.29 Turn OFF the MJB3 system power on the front panel. 12
3.1.30 Turn OFF the MJB3 air pressure by moving the switch to the down position. 3.1.31 Leave the mercury lamp N 2 cooling ON for 30 minutes to properly cool the lamp 3.1.32 After 30 minutes turn OFF the N2 cooling by moving the switch to the down position. 3.1.33 Enter the required information in the logbook. 13
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