Semiconductor Manufacturing Factories Research Articles

Characteristics of inorganic acid emission from various generation semiconductor manufacturing factories

With advancements in semiconductor industry technology, the gas emissions per wafer have decreased, but the emission compositions have shown significant differences. This study analyzed nine semiconductor plants representing different generations of process technologies, ranging from 3 μm to 12 nm technology nodes. Stack inspections were conducted on the acid, alkali, and organic exhaust systems to understand the characteristics of inorganic acid emissions in plants in different process technologies. The analysis showed that with technological process and air pollution control equipment advancements, the emissions of inorganic acids per wafer decreased by 38% compared to the first generation. It is worth noting that both hydrofluoric acid and nitric acid are identified as the primary pollutants in traditional semiconductor process plants. At the same time, H2SO4 was instead the primary pollutant in advanced process plants. Based on these characteristics, each plant has established relevant improvement strategies. After two years of improvement, the emissions of inorganic acids per wafer in each generation of plants are evidenced to have further decreased by 15–56%. Hence, it is shown that these initiatives and studies have successfully helped to reduce air pollution emissions and promote advanced green manufacturing.

ESD-Event Detector for ESD Control Applications in Semiconductor Manufacturing Factories

An electrostatic discharge (ESD)-event detector has been designed and fabricated in a single chip to detect and alarm the ESD events in semiconductor or integrated circuit (IC) manufacturing environments. The experiment measured results showed that the peak-to-peak voltage of the detected signal during an ESD event has a strong correlation with its ESD-stress voltage level. <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">The proposed ESD-event detector can determine a</b> detected <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">signal to be an ESD pulse if its signal amplitude is higher than the settable threshold and its duration time is under 500 ns.</b> The ESD-event detector circuit, including a <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">450 MHz</b> logarithmic amplifier, a comparator, and a time discriminator, has been implemented in a single chip with a total silicon area of only 693 × 563 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\mathbf{m}}^2$</tex-math></inline-formula> and fabricated by 0.18- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m CMOS process. <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">The detector can detect high-frequency transient signals up to 450 MHz, which has been successfully verified in the field tests by detecting the signals generated from the ESD generators, the human-body model tester, and the field-induced charged-device model tester.</b> The proposed ESD-event detector can efficiently perform the real-time ESD monitoring applications in the IC and semiconductor manufacturing factories.

Short-Term Scheduling Model of Cluster Tool in Wafer Fabrication

Since last decade, the cluster tool has been mainstream in modern semiconductor manufacturing factories. In general, the cluster tool occupies 60% to 70% of production machines for advanced technology factories. The most characteristic feature of this kind of equipment is to integrate the relevant processes into one single machine to reduce wafer transportation time and prevent wafer contaminations as well. Nevertheless, cluster tools also increase the difficulty of production planning significantly, particularly for shop floor control due to complicated machine configurations. The main objective of this study is to propose a short-term scheduling model. The noteworthy goal of scheduling is to maximize the throughput within time constraints. There are two modules included in this scheduling model—arrival time estimation and short-term scheduling. The concept of the dynamic cycle time of the product’s step is applied to estimate the arrival time of the work in process (WIP) in front of machine. Furthermore, in order to avoid violating the time constraint of the WIP, an algorithm to calculate the latest time of the WIP to process on the machine is developed. Based on the latest process time of the WIP and the combination efficiency table, the production schedule of the cluster tools can be re-arranged to fulfill the production goal. The scheduling process will be renewed every three hours to make sure of the effectiveness and good performance of the schedule.

The Preemptive Stocker Dispatching Rule of Automatic Material Handling System in 300 mm Semiconductor Manufacturing Factories

The integrated circuit (IC) manufacturing industry is one of the biggest output industries in this century. The 300mm wafer fabs is the major fab size of this industry. The automatic material handling system (AMHS) has become one of the most concerned issues among semiconductor manufacturers. The major lot delivery of 300mm fabs is used overhead hoist transport (OHT). The traffic jams are happened frequently due to the wide variety of products and big amount of OHTs moving in the fabs. The purpose of this study is to enhance the delivery performance of automatic material handling and reduce the delay and waiting time of product transportation for both hot lots and normal lots. Therefore, this study proposes an effective OHT dispatching rule: preemptive stocker dispatching (PSD). Simulation experiments are conducted and one of the best differentiated preemptive rule, differentiated preemptive dispatching (DPD), is used for comparison. Compared with DPD, The results indicated that PSD rule can reduce average variable delivery time of normal lots by 13.15%, decreasing average variable delivery time of hot lots by 17.67%. Thus, the PSD rule can effectively reduce the delivery time and enhance productivity in 300 mm wafer fabs.

The correlation between the firm's export orders and operational performances for semiconductor manufacturing Factories in Taiwan

This study treated semiconductor manufacturers as subjects and proposes, and validated the firm's export orders, by multiple regression analysis and operational performance for their correlation. The regression analysis result shows the positive and signifi cant relationship between the firms' export orders and operational performance. Great number of orders from international integrated component manufacturers and investment eff ect are the drives of growth of Taiwan semiconductor manufacturers

Exposure to Volatile Organic Compounds and Possibility of Exposure to By-product Volatile Organic Compounds in Photolithography Processes in Semiconductor Manufacturing Factories

ObjectivesThe purpose of this study was to measure the concentration of volatile organic compound (VOC)s originated from the chemicals used and/or derived from the original parental chemicals in the photolithography processes of semiconductor manufacturing factories.MethodsA total of four photolithography processes in 4 Fabs at three different semiconductor manufacturing factories in Korea were selected for this study. This study investigated the types of chemicals used and generated during the photolithography process of each Fab, and the concentration levels of VOCs for each Fab.ResultsA variety of organic compounds such as ketone, alcohol, and acetate compounds as well as aromatic compounds were used as solvents and developing agents in the processes. Also, the generation of by-products, such as toluene and phenol, was identified through a thermal decomposition experiment performed on a photoresist. The VOC concentration levels in the processes were lower than 5% of the threshold limit value (TLV)s. However, the air contaminated with chemical substances generated during the processes was re-circulated through the ventilation system, thereby affecting the airborne VOC concentrations in the photolithography processes.ConclusionTens of organic compounds were being used in the photolithography processes, though the types of chemical used varied with the factory. Also, by-products, such as aromatic compounds, could be generated during photoresist patterning by exposure to light. Although the airborne VOC concentrations resulting from the processes were lower than 5% of the TLVs, employees still could be exposed directly or indirectly to various types of VOCs.

Fire Safety Assessment Research for High-Tech Plants

Most of the buildings for high-tech plants are fireproof and the process equipment in the clean room is in compliance with high-standard fire prevention evaluation regulations such as National Fire Prevention Association (NFPA), Factory Mutual (FM),and Semiconductor Equipment and Materials International (SEMI). However, fire management is usually neglected though fire protection higher than domestic fire control regulations is applied. Fireproof and smoke-proof design of the original buildings can be damaged due to expansion of production facilities, causing a potential danger of a fire. Cases of fires in domestic semiconductor manufacturing factories were explored in this research and claim settlements provided by MSIG Mingtai InsuranceCo.,Ltd., Taiwan to high-tech plants were analyzed for determination of the quantified weights used by the insurance companies when evaluating fire risks of a building. The fire safety badge promoted by Architecture and Building Research Institute, and Ministry of the Interior was also discussed for reference of fire safety assessments of high-tech factory buildings in the future.

マイクロバブル技術の特徴と可能性

The physical and chemical characteristics of micro bubbles were investigated and some best practices of the micro bubble technology were reviewed concretely. The distribution, shrinkage process, rising velocity, and electric potential of micro bubbles were examined. An action of the physiological activity which forms large amounts of insulin like factor-1 is induced in the body of mice by the supply of micro bubbles as a sensorineural stimulation in the bubble bath. Further, the micro bubble technology makes an advance into the fields of cleaning process of semiconductor material and wastewater treating in some semiconductor manufacturing factories. Moreover, this technology works on the biological environmental improvement and water purification in closed water area.

Economic in-line inspection sampling strategy with learning effects

This paper presents an innovative approach to a wafer inspection strategy that incorporates learning dynamics in semiconductor manufacturing factories. Using the data from fabrication lines (fabs) we demonstrate algorithms for computing the sampling strategy in terms of the percentage of wafers to sample for a process in different phases of a product life cycle. The average selling price and wafer starts per weeks are considered in the model. The paper provides an optimal solution methodology and concludes that the learning benefits of quality control activities may achieve the most cost-effective operations.

Improvement of microwave ion source for higher B+ ion current

Microwave ion sources have many advantages over dc-discharge ion sources, such as long lifetime and high current for most ion species. But B+ ion current has been the only disadvantage. Here we experimentally study how to get higher B+ ion current by optimizing the shape and volume of the source chamber as well as by increasing the secondary electron emissivity of the chamber wall. We carry out the experiment with regard to the maximum ion beam, lifetime, and dynamic range of the beam current for various ion species. Then, we compare the data with those of the Bernas-type ion source that has been widely used in semiconductor manufacturing factories. As a result of the improvement, the performance of all the above-mentioned aspects of the microwave ion source exceed those of the Bernas-type ion source.

Active Microvibration Control of Precision Manufacturing Facilities with Smart Structure Using Piezoelectric Actuator.

A smart structure was tested for active microvibration control of a 2-story steel frame building model of a 5×3×4Hm outer size and a 2 500 kg total weight which was excited by ambient ground vibration. In the structure, piezoelectric actuators attached to the columns and the beams were used for the microvibration control by bending moment control of them. The controller was designed using the H ∞ control theory. The tests showed that the smart structure could effectively reduce the three-dimensional microvibration of the building model, and its applicability to floors and even entire buildings of semiconductor manufacturing factories having steel frame structures.

Fundamental study of earthquake isolation systems suitable for buildings of industrial facilities. 1st report Performance of earthquake isolation systems using hysteretic dampers.

For industrial facilities, such as computer centres, semiconductor manufacturing factories and fast breeder reactor power stations, earthquake isolation systems used for buildings should not only attenuate the seismic response of the buildings but also reduce the response of the internal equipment. From this point of view, isolation systems using various types of damper have been evaluated through both experimental tests of a 0.3 scale model of a building supported by rubber bearings and theoretical analysis, to find the most suitable systems for industrial facilities. The performance of two types of isolation system using friction dampers and lead shear dampers respectively was examined. The results showed that both systems using these hysteretic dampers could attenuate the response accelerations of the building and limit the excessive deflexion of rubber bearings. However neither system, particularly the system using friction dampers, was less effective in reducing the response acceleration of the internal equipment.