Filling Narrow Trenches by Iodine-Catalyzed CVD of Copper and Manganese on Manganese Nitride Barrier/Adhesion Layers

We present a process for the void-free filling of sub-100 nm trenches with copper or copper-manganese alloy by chemical vapor deposition (CVD). Conformally deposited manganese nitride serves as an underlayer that initially chemisorbs iodine. CVD of copper or copper-manganese alloy releases the adsorbed iodine atoms from the surface of the manganese nitride, allowing iodine to act as a surfactant catalyst floating on the surface of the growing copper layer. The iodine increases the growth rate of the copper and manganese by an order of magnitude. As the iodine concentrates near the narrowing bottoms of features, void-free, bottom-up filling of CVD of pure copper or copper-manganese alloy is achieved in trenches narrower than 30 nm with aspect ratios up to at least 5:1. The manganese nitride films also show barrier properties against copper diffusion and enhance adhesion between copper and dielectric insulators. During post-deposition annealing, manganese in the alloy diffuses out from copper through the grain boundaries and forms a self-aligned layer that further improves adhesion and barrier properties at the copper/insulator interface. This process provides nanoscale interconnects for microelectronic devices with higher speeds and longer lifetimes.Chemistry and Chemical Biolog

The Effect of Porogen Loading on the Stiffness and Fracture Energy of Brittle Organosilicates

Integrating porous low-permittivity dielectrics into Cu metallization is one of the strategies to reduce power consumption, signal propagation delays, and crosstalk between interconnects for the next generation of integrated circuits. The porosity and pore structure of these low-k dielectric materials, however, also affect other important material properties in addition to the dielectric constant. In this paper, we investigate the impact of porogen loading on the stiffness and cohesive fracture energy of a series of porous organosilicate glass (OSG) thin films using nanoindentation and the doublecantilever beam (DCB) technique. The OSG films were deposited by plasma-enhanced chemical vapor deposition (PECVD) and had a porosity in the range of 7~45%. We show that the degree of porogen loading during the deposition process changes both the network structure and the porosity of the dielectric, and we resolve the contributions of both effects to the stiffness and fracture energy of the films. The experimental results for stiffness are compared with micromechanical models and finite element calculations. It is demonstrated that the stiffness of the OSG films depends sensitively on their porosity and that considerable improvements in stiffness may be obtained through further optimization of the pore microstructure. The cohesive fracture energy of the films decreases linearly with increasing porosity, consistent with a simple planar through-pore fracture mechanism.Engineering and Applied Science

Atomic Layer Deposition (ALD) and Chemical Vapor Deposition (CVD) of Copper-based Metallization for Microelectronic Fabrication

Chemistry and Chemical Biolog

Prompt Space Optimizing Few-shot Reasoning Success with Large Language Models

Prompt engineering is an essential technique for enhancing the abilities of large language models (LLMs) by providing explicit and specific instructions. It enables LLMs to excel in various tasks, such as arithmetic reasoning, question answering, summarization, relation extraction, machine translation, and sentiment analysis. Researchers have been actively exploring different prompt engineering strategies, such as Chain of Thought (CoT), Zero-CoT, and In-context learning. However, an unresolved problem arises from the fact that current approaches lack a solid theoretical foundation for determining optimal prompts. To address this issue in prompt engineering, we propose a new and effective approach called Prompt Space. Our methodology utilizes text embeddings to obtain basis vectors by matrix decomposition, and then constructs a space for representing all prompts. Prompt Space significantly outperforms state-of-the-art prompt paradigms on ten public reasoning benchmarks. Notably, without the help of the CoT method and the prompt "Let's think step by step", Prompt Space shows superior performance over the few-shot method. Overall, our approach provides a robust and fundamental theoretical framework for selecting simple and effective prompts. This advancement marks a significant step towards improving prompt engineering for a wide variety of applications in LLMs.Comment: Natural language processing (NLP

Chemical Vapor Deposition (CVD) of Manganese Self-Aligned Diffusion Barriers for Cu Interconnections in Microelectronics

Barriers to prevent diffusion of copper, oxygen and water vapor were formed by CVD using a manganese precursor vapor that reacts with silica surfaces. The manganese metal penetrates only a few nanometers into the silica to make conformal amorphous manganese silicate layers. This MnSixOy was found to be an excellent barrier to the diffusion of Cu, O2 and H2O vapor. The adhesion strength of Cu to the MnSixOy was found to be sufficiently strong to satisfy the semiconductor industry requirements for interconnections in future microelectronic devices. CVD Mn dissolves into copper surfaces and then diffuses to increase adhesion to SiCNO capping layers.Chemistry and Chemical Biolog

Chemical Vapor Deposition of Cobalt Nitride and its Application as an Adhesion-Enhancing Layer for Advanced Copper Interconnects

An interlayer of face centered cubic (fcc) Co4N has demonstrated significant improvements in adhesion between copper and diffusion barrier layers. This fcc phase of Co4N was prepared by chemical vapor deposition (CVD) using bis(N-tert-butyl-N′-ethyl-propionamidinato)cobalt(II) and a reactant mixture of NH3 and H2 at substrate temperatures from 100 to 180°C. The Co/N atomic ratio and the phase of cobalt nitride film can be modified by adjusting the ratio of NH3 and H2 in the gas feedstock. The cobalt nitride films prepared by CVD are smooth, highly conformal, and stable against intermixing with copper up to at least 400°C. This fcc cobalt nitride material has very strong adhesion to copper due to the small lattice mismatch (−1 to 2%) between $fcc-Co_4N$ and fcc Cu. Copper wires should be stabilized against failure by electromigration when fcc cobalt nitride interlayers are placed between the copper and surrounding diffusion barriers.Chemistry and Chemical BiologyEngineering and Applied Science

Acupuncture modulates temporal neural responses in wide brain networks: evidence from fMRI study

<p>Abstract</p> <p>Background</p> <p>Accumulating neuroimaging studies in humans have shown that acupuncture can modulate a widely distributed brain network, large portions of which are overlapped with the pain-related areas. Recently, a striking feature of acupuncture-induced analgesia is found to be associated with its long-last effect, which has a delayed onset and gradually reaches a peak even after acupuncture needling being terminated. Identifying temporal neural responses in these areas that occur at particular time -- both acute and sustained effects during acupuncture processes -- may therefore shed lights on how such peripheral inputs are conducted and mediated through the CNS. In the present study, we adopted a non-repeated event-related (NRER) fMRI paradigm and control theory based approach namely change-point analysis in order to capture the detailed temporal profile of neural responses induced by acupuncture.</p> <p>Results</p> <p>Our findings demonstrated that neural activities at the different stages of acupuncture presented distinct temporal patterns, in which consistently positive neural responses were found during the period of acupuncture needling while much more complex and dynamic activities found during a post-acupuncture period. These brain responses had a significant time-dependent effect which showed different onset time and duration of neural activities. The amygdala and perigenual anterior cingulate cortex (pACC), exhibited increased activities during the needling phase while decreased gradually to reach a peak below the baseline. The periaqueductal gray (PAG) and hypothalamus presented saliently intermittent activations across the whole fMRI session. Apart from the time-dependent responses, relatively persistent activities were also identified in the anterior insula and prefrontal cortices. The overall findings indicate that acupuncture may engage differential temporal neural responses as a function of time in a wide range of brain networks.</p> <p>Conclusions</p> <p>Our study has provided evidence supporting a view that acupuncture intervention involves complex modulations of temporal neural response, and its effect can gradually resolve as a function of time. The functional specificity of acupuncture at ST36 may involve multiple levels of differential activities of a wide range of brain networks, which are gradually enhanced even after acupuncture needle being terminated.</p

Design of a CMOS current-mode voltage reference with low PVT sensitivity

This dissertation proposes a new PVT-Insensitive current-mode voltage reference utilizing second-order curvature-compensated technique. Implemented in TSMC-40nm process technology, the circuit has achieved a temperature coefficient of 18 ppm/◦C in the TT corner and Monte-Carlo T.C. of 27.33 ppm/◦C from −20 ◦C to 120 ◦C, demonstrating strong temperature insensitivity. The circuit, which operates a supply voltage range of 1.1V to 1.5V, gives a 622mV output reference voltage. By utilizing subthreshold MOSFET design, the power dissipation of the circuit is about 10.8uW at a 1.2V supply voltage. The simulation results have shown that the voltage reference has attained the line sensitivity of 0.0118%/V and the PSR of -58dB at 100Hz and reaching -24dB at 10MHz. The process sensitivity of the reference voltage 3.54%. Taken into account of line sensitivity, temperature span of 100 degree C and process sensitivity, the FOM for reference voltage is obtained as 3.71%. In view of circuit simplicity and low PVT sensitivity, the proposed circuit will be very useful of high precision analog circuit applications.Master of Science (Electronics

Studies on toxicity of multi-walled carbon nanotubes on Arabidopsis T87 suspension cells

The possible toxicities of agglomerates of multi-walled carbon nanotubes (MWCNTs) toward plant cells were evaluated. Arabidopsis T87 suspension cells were used as the model cells and decreases in values of cell dry weights, cell viabilities, cell chlorophyll contents, and superoxide dismutase (SOD) activities were seen for the cells cultured in media containing the agglomerates of MWCNTs, indicating the agglomerates of MWCNTs are toxic to the Arabidopsis T87 suspension cells. Moreover. the toxicities increased sharply as the diameters of the agglomerates of the MWCNTs became smaller. A concept based on the hypersensitive response is suggested to explain the possible toxic mechanism induced by the MWCNTs