Advancing technology nodes in semiconductor manufacturing require more demanding lithographic performance for
patterning. The advent of 45 nm development necessitated dual damascene lithography moving from a KrF-based
bilayer approach to one that includes an ArF photoresist for higher resolution. There are multiple methods for an ArF
dual damascene (via first, trench last) system, including bilayer, trilayer and hard mask approaches. Flash manufacturing
demands are sensitive to process cost of ownership, so more complex approaches such as trilayer and hard mask film
stacks were not as attractive. One method examined as an ArF dual damascene solution was a so-called "modified
bilayer" approach, which is a combination of both KrF and ArF resist materials; in particular, this film stack allows for
the use of ArF silicon-containing resists along with a variety of anti-reflective and gap fill underlayer materials. The
modified bilayer approach afforded many advantages, including chemical compatibility, etch performance and process
robustness. The modified bilayer approach represents a culmination of learning that has enabled 45 nm back end of the
line (BEOL) dual damascene processing with ArF silicon-containing photoresists.
The industry is facing a major challenge looking forward on the technology roadmap with respect to overlay control.
Immersion lithography has established itself as the POR for 45nm and for the next few nodes. As the gap closes between
scanner capability and device requirements new methodologies need to be taken into consideration. Double patterning
lithography is an approach that's being considered for 32 and below, but it creates very strict demands for overlay
performance. The fact that a single layer device will need to be patterned using two sequential single processes creates a
strong coupling between the 1st and 2nd exposure. The coupling effect during the double patterning process results in
extremely tight tolerances for overlay error and scanner capabilities.
The purpose of this paper is to explore a new modeling method to improve lithography performance for the 32nm node.
Not necessarily unique for double patterning, but as a general approach to improve overlay performance regardless of
which patterning process is implemented. We will achieve this by performing an in depth source of variance analysis of
current scanner performance and project the anticipated improvements from our new modeling approach. Since the new
modeling approach will involve 2nd and 3rd order corrections we will also provide and analysis that outlines current
metrology capabilities and sampling optimizations to further expand the opportunities of an efficient implementation of
such approach.
In this paper, an integrated monitoring architecture base don telephone maintenance networks for the optical CATV networks is proposed for the first time. Part of the field trail result is also shown. The integrated monitoring system includes the element monitoring sub-system (EMS), the RF performance monitoring sub-system (PMS), and the fiber monitoring sub-system (FMS). The EMS can monitor the active devices, including the optical transmitters and optical receivers in optical CATV networks. The PMS can monitor the RF performance of carrier-to-noise ratio, composite second order, composite triple beat, and per channel RF power level. The FMS can monitor the state of the fiber, and locate the fault for the point-to-point and the passive branching fiber networks. Both polling and alarm call-back methods can be executed. All the polling instructions and monitoring data are transmitted through the telephone maintenance networks. These three sub-systems share the common platform based on NT operation system, and user can access these three sub-systems just from a terminal. This integrated monitoring system not only provides the surveillance function, but also offers the administration function with user-friendly interface.
We demonstrate an in-service fault-locating and supervisory technique for multi-staged CATV optical distribution networks. The requirements of ultra-high dynamic range of an optical time domain reflectometer (OTDR) to diagnose the network can be tremendously relaxed by the introduction of optical switch and wavelength-division-multiplexing (WDM) technique. Any faults of the fiber links whether before, after, or between optical splitters can be located. The system operation is experimentally demonstrated in a two- staged eight-optical-node CATV distribution network. The degradation of system performance of carrier-to-noise ratio, composite second order, and composite triple beat due to in- service OTDR operation can be neglected. This surveillance system can provide real-time testing, saving the cost of dispatching a technician to perform routine testing and reducing the time taken to identify faults after an outrage occurs.
A single-longitudinal-mode erbium-doped fiber laser with passive multiple-ring-cavity (MRC) is proposed. The laser is fundamentally structured by inserting three different short ring cavities, which serve as mode filters, into the main cavity. When combined with a mode-restricting intracavity fiber Bragg grating, the MRC resonator ensures single- longitudinal-mode laser oscillation. The laser can successfully suppress the side-mode frequencies up to 1 GHz, and provide an output power of 23 mW with a side-mode suppression ratio of 51 dB at 1533 nm. The short-term linewidth of the laser output measured is about 2 kHz. The ability of this fiber laser as an AM transmitter source is also demonstrated.
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