21-02-2010, 07:23 AM
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INTRODUCTION
Lithography is akin to photography in that it uses light to transfer images onto a substrate.
Silicon is the traditional substrate used in chip making.
The key to create more powerful Microprocessors is the size of the lights wave lengths.
Shorter the wavelength the more transistors can be etched on to the Silicon wafer.
Lithography uses a wavelength of 240nm.
EUVL glass lenses will be replaced by mirrors.
Use smaller wavelength.
WHY EUVL
To reduce the wavelength of light used for imaging.
To design imaging system with ever layer numerical aperture.
Reason for changes
a) Resolution (RES)
b) Depth of focus (DOF)
Better resolution achieved by reducing and NA.
EUVL TECHNOLOGY
Different technology from what is familiar.
Properties of materials in EUVL are different from properties in visible and UV rays.
EUVL imaging are entirely reflective.
Reflectivity in near normal incidence is very low .
A laser is directed as a jet of xenon gas. When laser hits the Xenon gas it heats up and creates a plasma.
Once is created , electron begins to come off and radiates light at 13nm.
Light travels to condenser and is directed to the mask.
Pattern on the mask is reflected on to the series of four to six curved mirrors , reducing the size of the image and focusing the image onto the silicon wafer.
1.Multilayer reflectors
Inorder to achive reflectivities the reflecting surface are coatd with multi layer thin films
Resonance reflectivity approximately /2
2. EUV Cameras
Composed of 4mirrors
2types of euv cameras are1. small field micro setter like desidn known â„¢10x camers 2.proto type lithography camera
3. EUV masks
NO defects are ever allowed in a completed mask
Extremely flat and defect-free substrate, perfected by smoothing layer
All defects in multilayer reflecting stack must be completely repaired
No defects allowed in absorber layer
All defects in final absorber pattern must be completely repaired
(No wonder mask sets are so expensive!)
SOURCES OF EUV RADIATION
Laser produced plasmas.
Bending magnets.
The undulators associated with synchrotrons.
Development of discharging sources.
RESISTS
Strong absorption of EUV radiation.
Printing occurs in a very thin imaging layer.
Resist types are:
Silylated single-layer resist.
Refractory bilayer resists.
Tri-layer resists.
Successful resist must possesses excellent etch resistance.
ADVANTAGES
EUVL leverages much of the learning and supplier infrastructure established for conventional lithography.
EUVL technology achieves good depth of focus and linearity for both dense and isolated lines with low NA systems without OPC.
The robust4X masks are patterned using standard mask writing and repair tools and similar inspection methods can be used as for conventional optical masks.
The low thermal expansion substrates provide good critical dimension control and image placement.
Experiments have shown that existing DUV can be extended for use with EUV.
FUTURE OF EUVL
Projection photolithography to remain the semiconductor industry's.
Demonstrated in a full-field proof of Concept .
There are no known showstoppers that will prevent EUVL from
becoming a manufacturing reality.
CONCLUSION
Projection photolithography to remain the semiconductor industry's.
Work to determine EUVL will ever be ready for the production line.
Consensus is that 193 nm lithography will have to do the job.
Became crucial for any potential NGL to be able to address the printing of feature.
INTRODUCTION
Lithography is akin to photography in that it uses light to transfer images onto a substrate.
Silicon is the traditional substrate used in chip making.
The key to create more powerful Microprocessors is the size of the lights wave lengths.
Shorter the wavelength the more transistors can be etched on to the Silicon wafer.
Lithography uses a wavelength of 240nm.
EUVL glass lenses will be replaced by mirrors.
Use smaller wavelength.
WHY EUVL
To reduce the wavelength of light used for imaging.
To design imaging system with ever layer numerical aperture.
Reason for changes
a) Resolution (RES)
b) Depth of focus (DOF)
Better resolution achieved by reducing and NA.
EUVL TECHNOLOGY
Different technology from what is familiar.
Properties of materials in EUVL are different from properties in visible and UV rays.
EUVL imaging are entirely reflective.
Reflectivity in near normal incidence is very low .
A laser is directed as a jet of xenon gas. When laser hits the Xenon gas it heats up and creates a plasma.
Once is created , electron begins to come off and radiates light at 13nm.
Light travels to condenser and is directed to the mask.
Pattern on the mask is reflected on to the series of four to six curved mirrors , reducing the size of the image and focusing the image onto the silicon wafer.
1.Multilayer reflectors
Inorder to achive reflectivities the reflecting surface are coatd with multi layer thin films
Resonance reflectivity approximately /2
2. EUV Cameras
Composed of 4mirrors
2types of euv cameras are1. small field micro setter like desidn known â„¢10x camers 2.proto type lithography camera
3. EUV masks
NO defects are ever allowed in a completed mask
Extremely flat and defect-free substrate, perfected by smoothing layer
All defects in multilayer reflecting stack must be completely repaired
No defects allowed in absorber layer
All defects in final absorber pattern must be completely repaired
(No wonder mask sets are so expensive!)
SOURCES OF EUV RADIATION
Laser produced plasmas.
Bending magnets.
The undulators associated with synchrotrons.
Development of discharging sources.
RESISTS
Strong absorption of EUV radiation.
Printing occurs in a very thin imaging layer.
Resist types are:
Silylated single-layer resist.
Refractory bilayer resists.
Tri-layer resists.
Successful resist must possesses excellent etch resistance.
ADVANTAGES
EUVL leverages much of the learning and supplier infrastructure established for conventional lithography.
EUVL technology achieves good depth of focus and linearity for both dense and isolated lines with low NA systems without OPC.
The robust4X masks are patterned using standard mask writing and repair tools and similar inspection methods can be used as for conventional optical masks.
The low thermal expansion substrates provide good critical dimension control and image placement.
Experiments have shown that existing DUV can be extended for use with EUV.
FUTURE OF EUVL
Projection photolithography to remain the semiconductor industry's.
Demonstrated in a full-field proof of Concept .
There are no known showstoppers that will prevent EUVL from
becoming a manufacturing reality.
CONCLUSION
Projection photolithography to remain the semiconductor industry's.
Work to determine EUVL will ever be ready for the production line.
Consensus is that 193 nm lithography will have to do the job.
Became crucial for any potential NGL to be able to address the printing of feature.
