Provides a means to align a pattern on a chip to the pattern on a mask; and then to expose this pattern UV-light Mask: quartz + Cr pattern Photoresist substrate MASK ALIGNER: INTRODUCTION

Pump, service corridor Lamp power supply The aligner

Lamp house microscope Microscope Translation-control Mask holder Alignment stage Manometer box Mirror house Sample holder

Mercury lamp g - line : 436 nm h-line: 405 nm i - line 365 nm S-1800 series are g-line photoresit

Mercury lamp Life time: 600 h Nitrogen cooling is very important. Lamp must be cool before restarting … or you risk damaging the lamp. Therefore wait ~30 minutes after previous use. But it is better to leave the lamp on for several hours than turn off and on and off and on …. The first exposure after turning on the lamp should be done with no wafer. If the bulb explodes, it will fill the lithography area with toxic mercury vapor. This can cause severe neurological damage. EVACUATE THE LAB FOR AT LEAST 30 MIN. The mask aligner will also be seriously damaged.

Mercury lamp power supply It can be operated at constant power or constant Intensity Constant intensity  better reproducibility CI1 refers to 365 nm CI2 refers to 405 nm In constant intensity mode, the controller monitors the lamp intensity measure on the feedback sensor and varies the power supplied to the lamp to keep the intensity selected We work with CI2 because is the power meter we have. I= 25mW/cm 2

1.Lamp 2.Elipsoidal mirror 3.Cold mirror 4.Fly’s eyes lens 5.Condenser lens (32mm) 6.Frame for filters 7. Diffraction reducing lens plates (69 mm) 8. Turning mirror 9. Front lens UV-400 optics

WHAT’S NEW? BeforeNOW Turn on/off the whole machine, and Nitrogen in service corridor ONLY H2 and air switches on the aligner controller unit No vacuum  no possibility of different exposures modes Vacuum is available. Possibility to choose Height adjustment in contactNEVER height adjustment in contact. The Lever separation was not used The lever separation must be used Exposures in constant power mode Exposures in constant intensity mode

Air pressure and nitrogen switches ON/OFF ON all the time

ONLY MOVE THE THIN ENDS!!!!! Travel limits: X:  3mm Y:  3mm  :  3 

CONTACT ARM CONTACT- SEPARATION LEVER

Exposure modes ModeHow does it work?Resolutioncomments Vacuum Contact (HP) vacuum is drawn between the mask and the wafer prior exposure. ~0.8 µm pitchRISK OF BREAKING THE MASK Standard (ST) Hard contact mode During exposure, the vacuum holding the substrate to the chuck is switched off and positive nitrogen pressure is used to press the substrate against the mask. ~1.5 µm pitchRISK OF BREAKING THE MASK Soft Contact modeThe substrate is held to the mask just by mechanical pressure of chuck throughout the exposure. The vacuum holding the substrate to the chuck remains on. ~2 µm pitch SAFE Proximity contactExposures are made with a small gap between the mask and substrate. The gap is determined by the height adjustment. ?? Depends on separation SAFE. It has to be adjusted manually

1.Fiber optic light pipe 2.Single field /splitfield shutter 3.Rotation for focus 4.Objective separation for splitfield operation 5.Iris diaphram 6.Objectives SPLITFIELD= left shutter fully clockwise; right shutter fully anticlockwise Left objective=left shutter half way; right shutter fully anticlockwise Right objective=left shutter fully clockwise; right shutter half way MICROSCOPE