Transcript Presentations\Nanometer scale lithography Bernard and Strobelx

NANOMETER SCALE LITHOGRAPHY
NANOMETER SCALE LITHOGRAPHY, ALSO KNOWN AS NANOLITHOGRAPHY,
RELATES TO THE MAKING OF SEMICONDUCTOR DEVICES ON AN ATOMIC
SCALE LEVEL TO NO MORE THAN 100 NM. TECHNIQUES FOR MAKING THESE
DEVICES INCLUDING: PHOTOLITHOGRAPHY, X-RAY LITHOGRAPHY, ELECTRON
BEAM LITHOGRAPHY, EXTREME ULTRAVIOLET LITHOGRAPHY, AND CHARGED
PARTICLE LITHOGRAPHY AS WELL AS APPLICATIONS FOR THESE TECHNIQUES
WILL BE DISCUSSED THROUGHOUT THIS PRESENTATION.
DANIEL BERNARD – BENJAMEN STROBEL
EE 4611 – STANLEY G. BURNS
APRIL 29, 2013
TOPICS TO BE COVERED
TECHNIQUES
•
Photolithography
•
X-ray Nanolithography
•
Electron Beam Direct-Write Lithography
•
Extreme Ultraviolet Lithography
•
Charged Particle Lithography
APPLICATIONS
• Memory
• Small integrated circuits
• Silicon Wafers
PHOTOLITHOGRAPHY
Also known as optical lithography,
photolithography is a technique for
patterning various surfaces and has the
capability of producing sub patterns up to
100 nm with small wave lengths. Optical
nanolithography requires the use of liquid
immersion and resolution host. Most experts
feel that optical nanolithography techniques
are most cost effective than traditional
methods of lithography.
Image from: Huff
X-RAY
NANOLITHOGRAPHY
Another type of nanolithography is the x-ray
nanolithography which is quite different from
traditional x-ray lithography. It has the
ability to improve and extend optical
resolution of 15 nm by using short
wavelengths of 1 nm for the illumination. This
method is commonly used for batch
processing.
Image from: Wikipedia
ELECTRON BEAM
DIRECT-WRITE
LITHOGRAPHY
Used for creating memory cells and sub
patterns on the range of 7-40 nm sizes.
The process includes emitting a beam of
electrons in a pattern across a surface
covered in a thin film called a resist
(McCord). This “develops” the resist by
removing either exposed or non-exposed
regions. This resist can then be applied to
substrate materials via etching to
manufacture integrated circuits.
Image from: West Holland
ELECTRON BEAM DIRECT-WRITE
LITHOGRAPHY
The images on the right show two different 22 nm SRAM patterns with
different resists.
The resist’s properties can change the way the electron beam interacts
with it as shown on the right.
The first image is created by the XE151B resist, and has a high
resolution and contrast, whereas the second image, created using the
XE15CB, shows lowered contrast, but higher sensitivity.
Images from: Microelectronic Engineering
EXTREME
ULTRAVIOLET
LITHOGRAPHY (EUV)
Considered a next generation technique for
lithography.
It uses a wavelength of light in the ultraviolet
spectrum that should produce designs of about
13nm (Wikipedia).
In order to produce EUV, A technique much the
same as Electron beam is used only, cations must be
used.
Because cations can only be used in hot plasmas,
the power requirement for EUV approaches more
than 10kW (Harilal).
UEV requires the system to be in vacuum
(Wikipedia).
Image from: Nikon
APPLICATIONS AT
NIKON
Examples shown for use by Nikon:
•
DRAM
•
Flash Memory
Image shows a scale of progression of
Nikon’s lithographic creations using EUV
lithography variations.
Image from: Nikon
CONCLUSION
• Nanolithography is the process of imprinting nanometer scale patterns on a
substrate, often silicon wafers.
• The aforementioned techniques are the future of nano-scale circuitry and
memory.
• Nanolithography is used to create memory cells and small integrated circuits.
• There are still challenges including the immense amount of power required for
EUV techniques.
REFERENCES
Michael Huff, (2002) "MEMS fabrication", Sensor Review, Vol. 22 Iss: 1, pp.18 - 33
"Evaluation of direct patternable inorganic spin-on hard mask materials using electron beam lithography." Microelectronic Engineering 98 (2012): 226+.
Academic OneFile. Web. 25 Apr. 2013.
Anonymous. Xrl currents3.gif. Wikipedia. <http://en.wikipedia.org/wiki/File:Xrl_currents3.gif>.
McCord, M. A.; M. J. Rooks (2000). "2". SPIE Handbook of Microlithography, Micromachining and Microfabrication.
Harilal, S. S.; et al. (2006). "Spectral control of emissions from tin doped targets for extreme ultraviolet lithography". J. Phys. D 39 (3): 484.
Extreme ultraviolet lithography. 21 April 2013. Wiki. 25 April 2013.
Holland, West. Mapper Lithography . West Holland. 2012. <http://www.westholland.nl/newsletter/custom_images/Mapper_klein.jpg>.
Nikon. Figure 3. A generic EUV system. The Nikon eReview. 2013. Web Article. <http://www.nikonprecision.com/newsletter/fall_2008/article_05.html>.
Nikon. Figure 5. The Nikon EUVL development roadmap. The Nikon eReview. 2013. Web Article.
<http://www.nikonprecision.com/newsletter/fall_2008/article_05.html>.
KEY CONCEPTS
• The most common techniques of nanolithography include photolithography, x-ray lithography,
electron beam lithography, and extreme ultraviolet lithography.
• Applications of nanolithography include memory cells and integrated circuits.
• Different resists and masks can be used to change the contrast or sensitivity of a charged
beam.
• Commercial applications of flash memory have been produced at 25 nm (Nikon).
• Some methods of nanolithography require large amounts of power, such as EUV
nanolithography (sometimes around 10 kW of power).