This editorial explains what a structured abstract is and how to write one.

This guest editorial summarizes the Special Section on Novel Patterning Technologies.

Data throughput is a critical metric in a multiple electron-beam direct-write (MEBDW) system so that heavy-duty data processing equipment is required. The main challenge is about how to achieve high performance with cost-effective techniques. We propose a high compression rate algorithm for efficient data transfer and high speed decompression hardware to raise data throughput of the system. The hardware decoder uses pipeline architecture, a run-length encoding first-in-first-out queue, and parallel dispatch logic to increase the throughput. The decoder is evaluated on field-programmable gate array and simulated with layout images that are compressed using the proposed compression software. The results demonstrate 18.2% better compression rate and 254.8% better throughput than the previous work with similar hardware cost. Because no static random-access memory is used in the design, the channel numbers of the system can be easily scaled up, which makes it possible for the next-generation MEBDW system to achieve higher wafer per hour targets.

Acquiring three-dimensional (3-D) information becomes increasingly important for the development of block copolymer (BCP) directed self-assembly (DSA) lithography, as two-dimensional imaging is no longer sufficient to describe the 3-D nature of DSA morphology and probe hidden structures under the surface. Using the post-DSA membrane fabrication technique and scanning transmission electron microscopy tomography, we were able to characterize the 3-D structures of BCP in graphoepitaxial DSA hole shrink process. Different DSA structures of singlets formed in templated holes with different surface chemistry and geometry were successfully captured and their 3-D shapes were reconstructed from tomography data. The results reveal that strong polystyrene-preferential sidewalls are necessary to create vertical DSA cylinders and that template size outside of process window could result in defective DSA results in 3-D. Our study as well as the established 3-D metrology would greatly help to develop a fundamental understanding of the key DSA factors for optimizing the graphoepitaxial hole shrink process.

Self-aligned strategies are required because today’s feature sizes are beyond the resolution limit of the exposure tools. One self-aligned strategy is directed self-assembly (DSA), where block copolymers (BCP) are thermodynamically driven to self-align with a lithographically defined template with chemical contrast and/or topography. It would be particularly advantageous to also encode existing structures into thermodynamic information, then thermodynamics would cause BCP to self-align to these existing structures rectifying placement error. These existing features could be cut masks, which are required to fabricate devices from line and space arrays, or they could be interconnects. Here, we show a technique, by which metal–polymer interactions can be used in place of polymer–polymer interactions. These metal–polymer interactions, which cannot be adequately described by conventional surface energy comparisons, allow for a true self-aligned process. We begin by classifying process relevant metals including gold, aluminum, copper, tungsten, and cobalt, based upon their thermodynamic interactions with poly(styrene-block-methyl methacrylate). We then created guide patterns using metal and dielectric line space arrays. These patterns, when combined with DSA, allow for lines and space patterns to be self-aligned to any exposed metal features and reduce process constraints on exposure tools. Our process can also be used to align line and space patterns to metal layers during the back end of the line processing. A similar process could also be used to guide contact hole shrink to correct for placement error in the initial lithographic template.

The multibeam mask writer MBM-1000 is developed for semiconductor production for the 5-nm technology node. It is designed to accomplish high patterning resolution with a 10-nm beam and high throughput with blanking aperture array supporting data transfer rate of 300 Gbps and an inline real-time data path. It has better beam resolution than the EBM-9500 and has higher throughput at a shot count of more than 500 Gshot/pass. To further improve patterning resolution, pixel-level dose correction (PLDC) is implemented to MBM-1000. It enhances dose contrast by dose modulation pixel by pixel. Correction efficiency of PLDC is evaluated for linearity correction by simulation with a threshold dose model. It is concluded that PLDC corrects critical dimension linearity even without extra dose modulation and improves dose margin with additional dose modulation of 140%.

Nanomicropatterning of polymers and direct printing methods are becoming prominent nanofabrication tools in multiple fields of application from medicine to aerospace technology. All the available processes are very expensive, requiring complex equipment and highly trained staff. Often the desired pattern cannot be realized easily and the method used for the fabrication would be a direct consequence of the material of interest, with a significant limitation in case of highly viscous polymers. We propose a very simple, low cost method that exploits the pyroelectrohydrodynamic effect for patterning polymer fibers with high resolution. In particular, we focus on the fabrication of nanocomposite polymer fiber with good mechanical and electrical properties. We start from studying the instability phase of patterning for low concentrated polymeric solutions and discuss the condition of continuous printing. Moreover, the same technique is applied for the patterning of footpath as master for the realization of microfluidic chips. The simplicity of the method proposed, associated with the high-resolution patterning achievable at nanoscale, suggest innovative and widespread uses of general purpose for in situ and noninvasive instruments in different fields of research and business cases.

The photomechanism of extreme ultraviolet (EUV) exposures in chemically amplified photoresists is much different than that of previous lithographic wavelengths. Electrons generated during EUV exposure are demonstrated to be a source of acid production through a process referred to as electron trapping. Density functional theory modeling indicates that it is energetically favorable for the photoacid generator (PAG) molecule to decompose if an electron is trapped. Low-energy electrons (<10  eV) that are unlikely to produce holes and secondary electrons generate acid-indicating electron–PAG interactions that are capable of inducing decomposition. Additionally, solution phase reduction in PAGs via electrolysis is shown to produce acid. Furthermore, a more easily reduced PAG (i.e., higher likelihood of trapping an electron) produces a higher acid yield, further supporting electron trapping as a process of acid production regardless of the polymer matrix. An acid indicator, Coumarin 6, was used to determine the number of acids generated per absorbed EUV photon. The results of these measurements indicate that electron–PAG interactions are a source of acid production through electron trapping; thus, an increase in the number of electron-hole pairs available to induce chemical reactions would improve sensitivity.

The semiconductor industry continues to drive patterning solutions that enable devices with higher memory storage capacity, faster computing performance, and lower cost per transistor. These developments in the field of semiconductor manufacturing along with the overall minimization of the size of transistors require continuous development of metrology tools used for characterization of these complex three-dimensional device architectures. Optical scatterometry or optical critical dimension (OCD) is one of the most prevalent inline metrology techniques in semiconductor manufacturing because it is a quick, precise, and nondestructive metrology technique. However, at present OCD is predominantly used to measure the feature dimensions such as line-width, height, side-wall angle, etc. of the patterned nanostructures. Use of optical scatterometry for characterizing patterning process errors such as pitch-walking, overlay, etc. is fairly limited. Characterization of process-induced errors is a fundamental part of process yield improvement. It provides process engineers with important information about process errors, and consequently helps optimize materials and process parameters. Scatterometry is an averaging technique and extending it to measure the position of local process-induced errors and feature-to-feature variation is extremely challenging. This report is an overview of applications and benefits of using optical scatterometry for characterizing defects such as pitch-walking, overlay, and fin bending for advanced technology nodes beyond 7 nm. Currently, the optical scatterometry is based on conventional spectroscopic ellipsometry and spectroscopic reflectometry measurements, but generalized ellipsometry or Mueller matrix (MM) spectroscopic ellipsometry data provide important, additional information about complex structures that exhibit anisotropy and depolarization effects. In addition, the symmetry–antisymmetry properties associated with MM elements provide an excellent means of measuring asymmetry present in the structure. The useful additional information as well as symmetry–antisymmetry properties of MM elements is used to characterize fin bending, overlay defects, and design improvements in the OCD test structures are used to boost OCDs’ sensitivity to pitch-walking. In addition, the validity of the OCD-based results is established by comparing the results to the top down critical dimension-scanning electron microscope and cross-sectional transmission electron microscope images.

We demonstrate a hybrid “package-less” polydimethylsiloxane (PDMS)–complementary metal–oxide–semiconductor (CMOS)-FR4 system for contact imaging. The system embeds the CMOS image sensor directly in a PDMS layer instead of the standard chip package to support microfluidic structures much larger and more complex than those in prior art. The CMOS/PDMS layer is self-aligned to form a continuous, flat surface to provide structural support for upper microfluidic layers. The system consists of five layers of PDMS implementing fluid channels, valves, chambers, and inlets/outlets. A custom CMOS image sensor with integrated signal conditioning circuits directly captures light from sample fluid for high optical collection efficiency. Owing to the flexibility afforded by the integration process, the system demonstrates, for the first time, integrated valves in contact imaging. Moreover, we present the first direct comparison of the optical performance of a CMOS image sensor and a photomultiplier tube (PMT) in identical contact-imaging conditions. Measurements show that our CMOS sensor achieves 17 dB better signal-to-noise ratio (SNR) compared with a commercial PMT across a broad range of integration times, with a maximum SNR of 47 dB. Chemiluminescent testing successfully shows signal detection for different analyte concentrations and integration times. The contact-imaging system demonstrates a detection limit of 25 μM of a 9,10-diphenylanthracene-based solution.

This paper proposes a demodulation phase angle compensation (DPAC) for dual-mass MEMS gyroscopes with small frequency split (Δω) and low-quality factor (Q value), to reduce the quadrature interference on Coriolis signal output. The harmful contribution of quadrature error and demodulation phase angle drift to the gyroscope performances is analyzed and quantified. The quadrature stiffness correction (QSC) system based on DPAC is redesigned, and it was analyzed that the QSC would reduce the Δω and then affect the performances of the gyroscope. Wherein, the DPAC algorithm is implemented by a back propagation neural network. Finally, the experiments are arranged to verify the theoretical analysis. DPAC experiments were performed for both open-loop detection method and QSC method, respectively, for open-loop detection without DPAC (test 1), open-loop detection with DPAC (test 2), QSC without DPAC (test 3), and QSC with DPAC (test 4). The scale factor results based on these four tests are 15.384, 15.441, 16.652, and 16.731  mV  /  deg  /  s, respectively. When tests 2, 3, and 4 are compared to test 1, the bias stability results improved by 88%, 84%, and 97%, and the angle random walk improved by 28%, 23%, and 34%, respectively. Test 4 is proved to be the best type for bias performances, as is the case with a temperature range experiment from 60°C to −40  °  C, but the performances of its scale factor deteriorated. Moreover, the bandwidth is reduced by 4 Hz because of the QSC.