Parallel with the introduction of EUV lithography, immersion lithography is being extended to the 14- and 10-nm node, and the lithography performance requirements need to be tightened further to enable this shrink. Next to generic scanner system improvements, application-specific solutions are needed to follow the requirements for critical dimension (CD) control and overlay. The application-specific solutions need a holistic optimization approach for the scanner, the mask, and the patterning process. We will describe the holistic lithography systems architecture that enables dynamic use of high-order scanner optimization based on advanced actuators of projection lens and scanning stages. Next to the scanner system, key components of this architecture are an angle-resolved scatterometer to measure CD, overlay, and focus, and an off-tool computation server to calculate application-specific recipes for the scanner. Based on real production wafer data, we will show the benefit for CD control, focus control, and overlay control, and demonstrate lithography performance levels required for 14- and 10-nm node production.
Immersion lithography is being extended to the 20-nm and 14-nm node and the lithography performance requirements need to be tightened further to enable this shrink. In this paper we present an integral method to enable high-order fieldto- field corrections for both imaging and overlay, and we show that this method improves the performance with 20% - 50%. The lithography architecture we build for these higher order corrections connects the dynamic scanner actuators with the angle resolved scatterometer via a separate application server. Improvements of CD uniformity are based on enabling the use of freeform intra-field dose actuator and field-to-field control of focus. The feedback control loop uses CD and focus targets placed on the production mask. For the overlay metrology we use small in-die diffraction based overlay targets. Improvements of overlay are based on using the high order intra-field correction actuators on a field-tofield basis. We use this to reduce the machine matching error, extending the heating control and extending the correction capability for process induced errors.
We report on the technical progress in increasing the recording density of optical storage systems by means of improved read-channel signal processing and write-channel optimisation.
The recording density increase is realized by employing PRML (Viterbi)
bit detection in combination with improved timing recovery and adaptive equalisation algorithms, and by using a signal quality characterisation scheme which enables a proper control of the write process in the considered range of storage densities. The Blu-ray Disc (BD) optical disc system employing blue-violet laser with the wavelength of 405nm, objective lens with numerical aperture of 0.85 and disc cover layer thickness of 0.1mm is used as an experimental platform in our present study. Multi-track experimental results for both single-layer read-only (BD-ROM) and single-layer rewritable (BD-RE) media are presented to show the feasibility of the increased-density BD.
We present read-out results of a 50 GB disk with a blue laser and a NA=1.9 Solid Immersion Lens in a conventional focus and tracking actuator. Furthermore, we show a light path and a disk design that enable cover-layer incident near field recording on dual-layer disks with a capacity of 300 GB on a double-sided disk.