Lithography

About: Lithography is a research topic. Over the lifetime, 23507 publications have been published within this topic receiving 348321 citations.

Microscale control of stiffness in a cell-adhesive substrate using microfluidics-based lithography.

Abstract: In native tissues, the rigidity of the microenvironment provides important mechanical cues in directing cellular processes, including adhesion, spreading, migration, cytoskeletal organization, growth, differentiation, apoptosis, and tissue morphogenesis. 9] In particular, microscale variations in stiffness (with Young s modulus ranging from 100 Pa to 1 MPa) have been observed over length scales ranging from subcellular (< 5 mm) to multicellular (> 300 mm) dimensions in healthy and diseased tissues of the brain, bone, heart, and cartilage. Moreover, recent evidence suggests that heterogeneous distribution of mechanical properties is responsible for the spatial organization and differentiation of different germ layers during embryogenesis. Previously, most attempts to reconstruct microscale variations in substrate stiffness have used collagen-coated polyacrylamide gels, in which the stiffness can be tuned by varying the amount of bisacrylamide cross-linker. In constructing a single-step 16] or a continuous 18] gradient in substrate stiffness, these studies demonstrated a range of cellular behavior, most notably durotaxis (that is, the guidance of cell migration by microscale variations in substrate stiffness), with cells migrating from compliant toward stiff regions. To recapitulate the myriad microscale variations of stiffness in native and diseased tissues, it will be important to develop a technology for constructing a celladhesive substrate that exhibits a flexible spatial architecture with controllable local variations that are not limited to monotonic or single-step stiffness changes. Previously, we and others developed microfluidics-based lithography techniques (in which the fabrication of 3D gels was performed inside a microchannel) to pattern multiple 3D gels aligned to each other (Figure 1). Unlike other lithography techniques inside a microchannel, where particles are gelled in solution and flow away, our technique can produce aligned, multicomponent microstructures that adhere to the underlying substrate. Herein we extend this

Accurate lithography hotspot detection using deep convolutional neural networks

Abstract: As the physical design of semiconductors continues to shrink, the lithography process is becoming more sensitive to layout design. Identifying lithography hotspots (HSs) in the layout design stage appears to be more and more crucial for fast semiconductor development. In this direction, we propose an accurate HS detection method using convolutional neural networks. Our approach produces more accurate detection performance (95.5% recall and 22.2% precision) compared to previous approaches. In spite of the use of deep convolutional neural networks, our method achieves a fast detection time of 0.72 h/mm2. In order to quickly and accurately detect HSs, we not only utilize the nature of convolutional-neural networks but also make additional technical efforts to improve the performance of our framework, including inspection region reduction, data augmentation, DBSCAN clustering, modified batch normalization, and fast image scanning. To the best of our knowledge, our approach is the first CNN-based lithography HS detection.

Fountain solution image apparatus for electronic lithography

Abstract: A method and apparatus for printing an image in scanned electronic form on an ink receiving surface using ordinary printer''s ink. The method and apparatus employ quasi-lithographic techniques and equipment, but unlike conventional lithography, the method does not require the preparation, prior to the printing process, of a lithographic plate containing in permanent form the image to be printed. The scanned electronic image is used to form a fountain solution image on a lithographically blank plate by the selective deposition and/or removal of the fountain solution from the plate. Lithographic ink is applied to the fountain solution imaged plate and then transferred to an ink receiving surface, such as paper or an offset blanket. Thereafter, the lithographically blank plate is cleaned and ready for the formation of the same or a different fountain solution image.

Fabrication of molecular-electronic circuits by nanoimprint lithography at low temperatures and pressures

Abstract: We have utilized a modified version of thermal nanoimprint lithography to fabricate a rewritable, nonvolatile, molecular memory device with a density of 6.4 Gbit/cm2. It has the advantages of a relatively low operating temperature of (∼70 °C) and pressure of (<500 psi or 4.5 MPa), both of which are critical to preserving the integrity of the molecular layer. The architecture of the circuit was based on an 8×8 crossbar structure, with an active molecular layer sandwiched between the top and bottom electrodes. A liftoff process was utilized to produce the top and bottom electrodes made of Pt/Ti bilayers. The active molecular layer was deposited by the Languir–Blodgett technique. We utilized a new class of nanoimprint resist formulated by dissolving a polymer in its monomer. The formulation we used, was poly(benzyl methacrylate), dissolved in benzyl methacrylate with t-butyl peroxy 2-ethylhexanoate added as a self-initiator (8:90:2 by weight). The new resist allowed us to achieve Pt/Ti lines of 40 nm in width and 130 nm in pitch.

Characterization of near‐field holography grating masks for optoelectronics fabricated by electron beam lithography

Abstract: Direct write e‐beam lithography and reactive ion etching was used to fabricate square‐wave gratings in quartz substrates which serve as pure phase masks in the near‐field holographic printing of gratings. This method of fabricating these masks extends the flexibility of the printing technique by allowing both abrupt phase shifts as well as multiple grating pitches to be simultaneously printed from a single contact mask. Grating masks with periods in the 235–250 nm range have been produced and measured to be within 0.15 nm of the design period. Transmitted and diffracted beam powers have also been measured for various duty cycles and etch depths and are shown to be important parameters for ‘‘balancing’’ these interfering beams. Simple scalar diffraction modeling is used to qualitatively examine the dependence of diffraction on grating parameters, but the need for a more comprehensive modeling is illustrated. Prototype masks have been used to produce grating patterns on InP substrates using two different ul...