30-05-2012, 03:21 PM
extreme ultraviolet lithography
Extreme Ultraviolet Lithography.pdf (Size: 1.52 MB / Downloads: 82)
A brief history
Nearly all of today’s electronic devices rely on key internal semiconductor components, known as integrated circuits (ICs). ICs are manufactured through a critical process known as lithography, which is the determining factor in keeping pace with the quest of the electronics industry to shrink ICs and other related products even more.
Lithography is a patterning method that creates an IC layout on a resist layer of a silicon wafer or other semiconducting substrate. It mainly consists of three parts: a) the pattern printer, b) photoresist technology, and c) the mask fabrication.
Lithography technology was introduced to the semiconductor industry when ICs were invented in 1958. The original lithography used light of the visible g-line (436 nm) and the ultraviolet i-line (365 nm), which was easily produced with a mercury arc lamp. With the progress of technology and the reduction of the feature size, the wavelength of the exposure light had to be reduced several times. When the IC feature size was reduced to about half a micron (500 nm), the g-line and the i-line could no longer be used, and therefore deep ultraviolet 248 nm KrF and 193 nm ArF excimer lasers were introduced. Currently, the 193 nm lithography combined with immersion and double patterning technology is the state of the art.
The map of worldwide research
Since 1988, many studies on EUVL have been conducted in North America, Europe, and Asia, through state sponsored programs, industrial consortiums, and individual companies.
In the early and mid-1990s, systematic research was mainly performed by the Lawrence Livermore National Laboratory (LLNL), Sandia National Laboratory (SNL), and Lawrence Berkeley National Laboratory (LBNL), as well as AT&T Bell Laboratories and several universities. In 1997, an industrial consortium, the EUV LLC, was formed by Intel, Motorola, and Advanced Micro Device (AMD), to continue work on EUVL. At the same time, the Virtual National Laboratories (VNL) was also formed by LLNL, SNL, and LBNL to conduct a program sponsored by EUV LLC.
In Europe, an industrial consortium, the Extreme Ultraviolet Concept Lithography Development System (EUCLIDES), was formed in 1998 by ASM Lithography (ASML), Carl Zeiss, and Oxford Instruments. Since then, EUVL studies in Europe have made significant progress, with ASML leading.
The challenges
To date, no “showstoppers” have been identified, but challenges are present in almost every aspect of EUVL technology. Some challenges are common to all NGL technologies, e.g. resist resolution and line-edge roughness (LER). Other challenges are unique to EUVL, e.g. resist outgassing owing to the EUVL high-vacuum environment. In the past 20 years the main topics of research in EUVL have been: source, optics, mask, multilayer coating, resist, metrology, reticle handling, defects, and contamination control.
Today, commercial alpha lithography step-and-scan tools are installed with full field capability; EUVL power at intermediate focus (IF), however, has not yet met the target of 180 watt intermediate focus (IF) power required for volume manufacturing. EUV IF power has been improving gradually from xenon to tin discharge-produced plasma (DPP), or to laser-produced plasma (LPP).
The opportunities
EUVL was originally planned in 1988 for the 100 nm technology node. However, the extension of optical lithography delayed the adoption of EUVL and other NGL technologies. In 1997, implementation was predicted for the 65 nm node. A further extension of optical lithography reduced the predicted EUVL implementation to under the 45 nm node. The immersion exposure technology combined with the double patterning method delayed EUVL implementation further. At the moment it is predicted that EUVL will have some pilot-scale applications at the 32 nm technology node or will be used in full production for the 22 nm half-pitch technology node.
Extreme Ultraviolet Lithography.pdf (Size: 1.52 MB / Downloads: 82)
A brief history
Nearly all of today’s electronic devices rely on key internal semiconductor components, known as integrated circuits (ICs). ICs are manufactured through a critical process known as lithography, which is the determining factor in keeping pace with the quest of the electronics industry to shrink ICs and other related products even more.
Lithography is a patterning method that creates an IC layout on a resist layer of a silicon wafer or other semiconducting substrate. It mainly consists of three parts: a) the pattern printer, b) photoresist technology, and c) the mask fabrication.
Lithography technology was introduced to the semiconductor industry when ICs were invented in 1958. The original lithography used light of the visible g-line (436 nm) and the ultraviolet i-line (365 nm), which was easily produced with a mercury arc lamp. With the progress of technology and the reduction of the feature size, the wavelength of the exposure light had to be reduced several times. When the IC feature size was reduced to about half a micron (500 nm), the g-line and the i-line could no longer be used, and therefore deep ultraviolet 248 nm KrF and 193 nm ArF excimer lasers were introduced. Currently, the 193 nm lithography combined with immersion and double patterning technology is the state of the art.
The map of worldwide research
Since 1988, many studies on EUVL have been conducted in North America, Europe, and Asia, through state sponsored programs, industrial consortiums, and individual companies.
In the early and mid-1990s, systematic research was mainly performed by the Lawrence Livermore National Laboratory (LLNL), Sandia National Laboratory (SNL), and Lawrence Berkeley National Laboratory (LBNL), as well as AT&T Bell Laboratories and several universities. In 1997, an industrial consortium, the EUV LLC, was formed by Intel, Motorola, and Advanced Micro Device (AMD), to continue work on EUVL. At the same time, the Virtual National Laboratories (VNL) was also formed by LLNL, SNL, and LBNL to conduct a program sponsored by EUV LLC.
In Europe, an industrial consortium, the Extreme Ultraviolet Concept Lithography Development System (EUCLIDES), was formed in 1998 by ASM Lithography (ASML), Carl Zeiss, and Oxford Instruments. Since then, EUVL studies in Europe have made significant progress, with ASML leading.
The challenges
To date, no “showstoppers” have been identified, but challenges are present in almost every aspect of EUVL technology. Some challenges are common to all NGL technologies, e.g. resist resolution and line-edge roughness (LER). Other challenges are unique to EUVL, e.g. resist outgassing owing to the EUVL high-vacuum environment. In the past 20 years the main topics of research in EUVL have been: source, optics, mask, multilayer coating, resist, metrology, reticle handling, defects, and contamination control.
Today, commercial alpha lithography step-and-scan tools are installed with full field capability; EUVL power at intermediate focus (IF), however, has not yet met the target of 180 watt intermediate focus (IF) power required for volume manufacturing. EUV IF power has been improving gradually from xenon to tin discharge-produced plasma (DPP), or to laser-produced plasma (LPP).
The opportunities
EUVL was originally planned in 1988 for the 100 nm technology node. However, the extension of optical lithography delayed the adoption of EUVL and other NGL technologies. In 1997, implementation was predicted for the 65 nm node. A further extension of optical lithography reduced the predicted EUVL implementation to under the 45 nm node. The immersion exposure technology combined with the double patterning method delayed EUVL implementation further. At the moment it is predicted that EUVL will have some pilot-scale applications at the 32 nm technology node or will be used in full production for the 22 nm half-pitch technology node.