Semiconductor Production Processes Research Articles

Applications of CMOS image sensors: Applications and innovations

As semiconductor production processes continue to advance, CMOS image sensors are becoming increasingly popular and are gradually replacing traditional CCD sensors as the mainstream option in the market. Because CMOS image sensors adopt the standard CMOS semiconductor production process, which provides advantages such as low static power consumption, large noise tolerance, strong anti-interference ability, and fast working speed. This article is going to provide an overview of CMOS image sensors and examine their various applications. To achieve this, this article will provide some background information on CMOS image sensors, including a discussion of their structure, components, and working principles. A comprehensive literature review was conducted to explore the characteristics and benefits of CMOS image sensors in applications such as intelligent surveillance systems (ISS), space, and medical. This paper also discusses recent advances in CMOS image sensor technology, namely backside illumination, global shutter, and 3D imaging, and their impact on various industries. Despite the advantages of CMOS image sensors, they still have some limitations and shortcomings. Therefore, further progress in industrial development is necessary to improve the quality of these products.

A study on the Treatment of Hydrofluoric Acid Wastewater from Semiconductor Manufacturing Processes and the Possibility of Reuse of reclaimed water

Objectives : By eliminating fluorine and other ions through precipitation of fluoride and UF, RO membrane filtration using the hydrofluoric acid wastewater generated from the semiconductor production processes, this study aimed to investigate the possibility of the reuse of the reclaimed wastewater for the processes.Methods : For the experiment, firstly, the 2-stage precipitation of fluoride was done using Ca(OH)2 and PAC and it aimed to judge whether the water quality standards for reuse by each market were satisfied by eliminating colloidal particles and then other metal ions through the UF and RO membrane filtration.Results and Discussion : About 93 % of F- was removed through the 1st and 2nd precipitation. It can be also removed ammonium, phosphate ions, through the UF membrane filtration, about 95 % of particulate matter was removed and finally, the water quality for reuse was satisfied through RO filtration.Conclusion : This study found that the fluorine wastewater generated from the semiconductor production processes can be reused by precipitation and filtration methods without going through the existing complicated treatment methods. In the future, through such treatment procedures, it is expected to be able to secure the reuse of the reclaimed wastewater in the process.

Micromolding fabrication of biocompatible dry micro-pyramid array electrodes for wearable biopotential monitoring

Thin dry electrodes are promising components in wearable healthcare devices. Assessing the condition of the human body by monitoring biopotentials facilitates the early diagnosis of diseases as well as their prevention, treatment, and therapy. Existing clinical-use electrodes have limited wearable-device usage because they use gels, require many preparation steps, and can be uncomfortable to wear. Dry electrodes can improve these issues and have demonstrated performance on par with gel-based electrodes, providing advantages in mobile and wearable applications. However, the materials and fabrication methods used are not yet at the level of disposable gel electrodes for low-cost mass manufacturing and wide adoption. Here, a low-cost manufacturing process for thin dry electrodes with a conductive micro-pyramidal array (MPA) is presented for large-scale on-skin wearable applications. The electrode is fabricated using micromolding techniques in conjunction with solution processes in order to guarantee ease of fabrication, high device yield, and the possibility of mass production compatible with current semiconductor production processes. Fabricated using a conductive paste and an epoxy resin that are both biocompatible, the developed MPA electrode operates in a conformal, non-invasive manner, with low skin irritation, which ensures improved comfort for brief or extended use. The operation of the developed electrode was examined by analyzing electrode-skin-electrode impedance, electroencephalography, electrocardiography, and electromyography signals and comparing them with those measured simultaneously using gel electrodes.

Robust Multivariate Control Chart Based on Goodness-of-Fit Test

This paper proposes a distribution-free multivariate statistical process control (MSPC) chart to detect general distributional changes in multivariate process variables. The chart is deployed based on a multivariate goodness-of-fit test, which is extendible to high-dimensional observations. The chart also employs data-dependent control limits, which are computed on line along with the charting statistics, to ensure satisfactory and robust charting performance of the proposed method. Through theoretical and numerical analyses, we have shown that the proposed chart is exactly distribution-free and able to operate with an unknown in-control (IC) distribution or limited reference samples. The chart also has robust IC performance as well as satisfactory out-of-control (OC) detection power for general process changes without any assumption of the process distribution. A real-data example in semiconductor production processes is presented to demonstrate the application and effectiveness of our method.

Highly Sensitive and Selective Gas Sensors Based on Oxide Nanomaterials for Electronic Nose

The functional convergence of the Internet with radio-frequency identification and sensors has led to the era of the Internet of Things (IoT), which is a computing concept in which everyday objects are online and communicate via the Internet. In particular, the IoT is effective and appropriate for monitoring and controlling objects in hazardous environments to enable people to access them. In order to apply gas sensors to the IoT, operation at room temperature (low power consumption), a high efficiency (sensitivity, response/recovery time, and stability), low-cost fabrication, miniaturization, and easy integration with circuits are essential because these factors enhance the feasibility of utilizing a gas sensor, thereby enabling the collection, processing, analysis, and dissemination of valuable information gathered from a variety of environments. Among various types of gas sensors, semiconducting gas sensors based on various metal oxides are considered to be the strongest candidate for the application in IoT owing to their small size, simplicity in operation, low cost, and compatibility with integrated circuits. A wide variety of nanostructured metal oxides, including nanowire, nanobelt, nanorods, nanosheets, nanospheres, and nanotubes has been exploited for semiconductor gas sensors during the past decade. Despite these efforts, achieving a reproducible fabrication, easy integration with other circuits, and compatibility with well-established semiconductor production processes that are related to mass production have remained challenges for the utilization of the semiconducting sensors in the IoT. In the presentation, we show our research efforts to synthesize well-ordered metal-oxide nanostructures such as nanorods, nanohemispheres, nanospheres and nanowells using physical vapor deposition (PVD) methods for the high performance chemoresistive gas sensors.

An Electrode Sets with a Cylindrical Cathode and a Platy Anode for Reclamation of TFT-LCD Surface

The low yield rate of ITO thin-films is well known in semiconductor production processes. In the current study, an electrode sets with a cylindrical cathode and a platy anode as a reclamation process for the nanoscale removal of the indium tin oxide (ITO) nanostructure from the color filter surface of TFT-LCD displays is presented. In the current experiment, the major interest lies in the features of the technology and the design of the cylindrical cathode and the platy anode for the electrochemical etching process. For this process a steep gradient of the platy anode provides large discharge mobility and a better removal effect. A thin platy anode, a small gap-width between the cylindrical cathode and the ITO surface, or a high flow rate of electrolyte corresponds to a higher removal rate of the ITO-layer. A large current flow combined with a high feed rate of the display also results in a fast removal rate. By establishing a recycling process for the ultra-precise removal of the thin-film nanostructure, the optoelectronic semiconductor industry can effectively recycle defective products with a reduction of both production costs and pollution.

Design of an Oblique Tool for the Nano Removal Process

A system design for a recycling process for the nano removal of the indium tin oxide (ITO) nanostructure from the color filter surface of TFT-LCD displays is presented. The low yield rate of ITO thin-films is well known in semiconductor production processes. By establishing a recycling process for the ultra-precise removal of the thin-film nanostructure, the optoelectronic semiconductor industry can effectively recycle defective products with a reduction of both production costs and pollution. In the current experiment, the major interest lies in the features of the technology and the design of an oblique cathode for the electrochemical removal process. For this process a steep gradient of the oblique cathode provides large discharge mobility and a better removal effect. A thin oblique cathode, a small gap-width between the cathode and the ITO surface, or a high flow rate of electrolyte corresponds to a higher removal rate of the ITO-layer. A large current flow combined with a high feed rate of the display also results in a fast removal rate.

Volatility and vapourisation characterisation of new precursors

The introduction of new chemicals into semiconductor production processes is an expensive, time consuming exercise. A key parameter required to ensure equipment set up is well suited to the source from the outset of trials is reliable precursor volatility data. In this paper we present the latest vapour pressure values for the technologically interesting Hf and Ru precursors and corresponding thermogravimetric analysis results. A discussion on the interpretation of the values obtained highlights the careful considerations required to ensure promising source materials are not ruled out prematurely.

Numerical and Experimental Investigation of Wet Chemical Etching of Silicon Wafers

Wet chemical etching is widely used in semiconductor production processes. The advantage lies in low investment costs and the absence of mechanical stress during etching. This method allows producing of extremely thin and flat wafers. However, etching is strongly influenced by hydrodynamics. To estimate the wafer surface profile after wet chemical etching, numerical simulations of fluid flow coupled with species transport using a simplified chemical reaction are carried out. It is shown that this approach can be applied with good accuracy to estimate etching rate for various operation conditions.

Active control of a pneumatic isolation table using model following control and a pressure differentiator

Abstract Pneumatic vibration isolation systems are widely used in semiconductor production processes. Most of them are controlled with nozzle-flapper type pneumatic servo valves. However, these servo valves require large exhaust air flow rates in order to control pressure precisely. In this paper, the model following control method was applied using a pressure differentiator and a spool type servo valve to actively control a pneumatic isolation table. Experiments were carried out on an air-spring system supporting a heavy granite bed, the displacement of which was modeled with a single degree of freedom. The experimental results gained in this research demonstrate the possibility of realizing a more efficient vibration isolation system than the conventional system using nozzle-flapper type servo valves. More specifically, this investigation showed about a 90% decrease in the steady-state exhaust air flow rate.

Standardization and differentiation of semiconductor production processes

Standardization and differentiation of semiconductor production processes

Realization of virtual sub chamber on active controlled pneumatic isolation table with pressure differentiator

Pneumatic isolation tables are widely used in semiconductor production processes. Softer air-springs for the table are now needed because the semiconductor line width continues to decrease. In this paper, a new method for developing a soft air-spring virtually is proposed through feedback control of the differentiated pressure. Since the pressure change in the chamber is very small, it is difficult to obtain the differentiated pressure by discrete simultaneous differentiation of the pressure. Instead, this value is obtained through direct measurements by a newly developed pressure differentiator. The effectiveness of the proposed method is demonstrated experimentally.

CONTROL OF A VIBRATION ISOLATION SYSTEM USING PRESSURE DIFFERENTIATORS AND SPOOL TYPE SERVO VALUES

Active control type pneumatic isolation systems are widely used in semiconductor production processes. Most of them are actively controlled by nozzle flapper type servo valves, since they have fine characteristics as imperfect pressure integrators. But nozzle flapper type servo valves exhaust a lot of compressed air, for the sake of controllability. In this research, we firstly develop a pressure differentiator using an isothermal chamber, a cylindrical type laminar flow element and a differential pressure sensor. Then, by using the developed pressure differentiator and a spool type servo valve, an imperfect pressure integration system with much lower exhausted air flow rate compared to the system with nozzle flapper type servo valve, is constituted. Finally, the proposed pressure integration system is applied to the control of active vibration isolation system. The experimental results indicate superior performance of the developed system, especially in much lower energy consumption.

Vapour pressure measurement of low volatility precursors

The introduction of new chemicals into semiconductor production processes is an expensive, time consuming exercise. A key parameter required to ensure equipment set up is well suited to the source from the outset of trials is reliable precursor volatility data. In this paper we present details of a newly commissioned vapour pressure (VP) measurement system and latest vapour pressure values for the technologically interesting Hf and Ta precursors pentakis(dimethylamido)tantalum (PDMAT) and tetrakis(ethylmethylamido)hafnium (TEMAH). Calibration data is also presented to illustrate the accuracy of the equipment.

Local Agglomeration and Global Networks Of the Semiconductor Industry: a Comparative Study of U.S. and Japanese Firms

The objective of this study is to examine the spatial organization of the U.S. and Japanese firms in the semiconductor industry. Our analyses give special consideration to the nature of the activities undertaken in the semiconductor production processes, the nature of the firm organization, the nature of the firm ownership, and the geographical area of analysis. Our approach is essentially diagrammatic in order to incorporate all the above factors. Therefore, unlike past studies, our study places special emphasis on tracing the connections between the whole spatial chain of production activities. The result is that different stages within the semiconductor production process have different geographical features, and that even the same vertically integrated sectors in the semi‐conductor industry that differ by Japanese or U.S. ownership have quite different geo‐graphical organizations.

Ultrasonic flowmeter for the accurate metering of gases for semiconductor processing

Semiconductor production processes such as chemical vapor deposition rely upon accurate control of the flow rate (in the range of 1–1000 standard cm3/min) of several ultrapure, yet highly toxic and/or reactive gases. Currently, thermal mass flow meters (TMFMs) are widely used in industry for these processes. Complications with the use of TMFMs arise because the flow must be divided (due to limited dynamic ranges) and calibration is normally performed with inert gases. In the present research, an ultrasonic Doppler shift flowmeter has been developed to measure gas flows. Measurements of the flow-induced phase shift of an acoustic plane wave propagating in an unobstructed tube, combined with the speed of sound of the gas, are used to determine the mean gas velocity. The combination of the mean gas velocity with measurements of the pressure and temperature allow calculation of the mass flow rate. The experimental system uses stainless steel tubes of diameter 0.05–0.1 cm, and frequencies near 100 kHz. No division of the flow is necessary. Prototype meters indicate that sensitivities on the order of 0.75°/standard cm3/min are possible. Experimental data of two prototype systems using different geometries and receivers will be presented. [Work supported by NIST.]

Perhalogenated Organic By-Products from Plasma Etching Processes and Their Effects on Human Health and Environmental Impact

AbstractComplex analytical and toxicological studies of the waste products from aluminium plasma etching were performed over a four-year period. Many different organic compounds were identified and quantified in the waste gases, vacuum pump oils, and the solid debris collected from the air pipe systems. The identified compounds were exclusively perhalogenated hydrocarbons. Toxicological investigations showed clear genotoxic, embryotoxic, and teratogenic effects resulting from the waste products.The study left no doubt, that workers in semiconductor production processes are potentially in danger of coming in contact with small amounts of plasma by-products, either through accidents, maintenance procedures, or insufficient protection.

Waste Generation and Minimization in Semiconductor Industry

Semiconductors are electrical devices that perform functions such as processing and display, power handling, and conversion between light and electrical energy. Semiconductor production processes involve over 100 proprietary solutions and 200 generic materials to achieve the final product. This industry generates significant quantities of spent solvents and liquids containing metals. The economic and liability incentives caused by increasing disposal costs and more stringent regulations are resulting in efforts to minimize such wastes at the source. This paper provides information about: (1) The type and quantity of wastes produced by this industry, much of which are listed hazardous wastes; (2) the hazardous waste disposal problems facing this industry; and (3) waste minimization case studies.

Performance characteristics of the Genus Inc. 1510 high energy ion implantation system

The use of high energy ion implantation in semiconductor production processes has expanded significantly in the past few years. In order to meet the requirements of these production users. Genus Inc. has developed the 1510 MeV ion implantation system. The 1510 is a second-generation high energy ion implanter and is an evolution of the market leader Genus 1500 system. In this work, a review of the key performance characteristics of the system are presented from a users point of view. Included are parameters such as beam current, beam stability, implant profiles, wafer throughput, particle performance, ease of operation, and serviceability. In particular, the following enhancements in the 1510 are highlighted: (1) ion source innovations, (2) control system and user interface enhancements, (3) automation capabilities, (4) uniformity enhancements, and (5) high tilt angle capabilities.

Standardisation

A discussion of the current position in the establishment of standards for semiconductor production materials and processes.