Batch-type Furnace Research Articles

Effect of Oxide Thickness by Metallic Residue during Radical Oxidation Using Vertical Batch-Type Furnace Equipment on 300-Mm-Diameter Silicon Substrates

Metallic residues have a detrimental effects on device performance as well as retard gate oxide growth rate to induce unintended thinner oxide layer. In this study, we found that oxide thickness could be subjective to metallic residues on the edge of silicon substrate. Hydrogen-assisted radical oxidation was investigated using vertical batch-type furnace equipment for a 300-mm wafer fab. Radical oxidation has been used to improve gate oxide quality overcoming the disadvantages of conventional wet or dry thermal oxidation for some applications. Since the radical oxidation method reduces dangling bonds and defects in the oxide layer due to activated oxygen radicals, a high-quality oxide film can be formed. It also helps improve reliability due to reduced dependence on the silicon crystal direction of oxidation, enabling uniform membrane deposition of stress-focused corner rounding oxidation. In addition, it has excellent throughput as it is possible to process up to 100 wafers simultaneously. This study has shown that as the number of wafers with metallic residues in the dummy pattern on the edge due to the wafer edge exposure (WEE) difference for each photo step increases in the same batch for radical oxidation, the median thickness has decreased. When the silicon wafer with the metallic residue was included within the same batch of the furnace equipment, the thickness of the oxide layer was reduced by 1.8% compared to when the metallic residue-free silicon wafer was included. The radical oxygen have a tendency to react to tungsten rather than silicon, which reduces the O2 value required to form SiO2 and lowers the thickness, which is due to the difference in electronegativity between silicon and tungsten, 1.9 and 2.36 respectively. The study is expected to improve gate oxide quality by controlling metal residues on the wafer edge or backside during the fab process.

Numerical analysis of nozzle shape effect on fluid motion in LPCVD batch-type furnace

Numerical analysis of nozzle shape effect on fluid motion in LPCVD batch-type furnace

Reheating time optimization for metal products in batch-type furnaces

A novel approach for the real-time optimization of reheating times of metal products in a batch-type furnace is presented. The considered furnace operates at a constant setpoint temperature and the product temperature asymptotically reaches its final value. The sensitivity of the reheating time with respect to the system parameters increases towards the end of the reheating process. A simple first-principles mathematical model of the furnace is developed as a basis for the parameter estimation and optimization. Unknown parameters of the model are estimated and repeatedly updated based on measurements of the mean product temperature before and after the reheating process. The estimation results are grouped in classes of similar products. Based on the estimated parameters of a product class, the optimal reheating time for a product to reach a desired temperature is calculated. The developed method is tested on a finite-element model of the furnace with perturbed parameters to analyze the efficiency, accuracy and robustness of the proposed approach. The numerical results show that highly accurate results can be achieved at very low computational costs.

Investigation of Hollow Microspheres Obtained in Thermal Plasma Jet Using Ash-Slag Wastes from CHP in Kemerovo Oblast

The processes occurring during the formation of hollow microspheres in a thermal plasma jet on the basis of ash-slag waste from CHP in Kemerovo Oblast are studied. The results of physical and chemical studies (scanning electron microscopy, energy-dispersive x-ray and infrared spectroscopy) of the initial raw material and the obtained microspheres based on it are presented. A comparative analysis is performed of hollow microspheres obtained by the conventional method in batch-type furnaces at CHP in Kemerovo Oblast and microspheres obtained using thermal plasma.

Modeling Effective Thermal Conductivity of Randomly Distributed Loads of Mono-Sized Parts of Arbitrary Geometry

Abstract A new model of the effective thermal conductivity of randomly distributed loads of mono-sized metal parts of arbitrary geometry heated under natural convective and radiation heat transfer has been developed. A series of transient heating experiments has been performed in a batch-type furnace using loads comprised of parts of various geometries, sizes, steel grades, and void fractions and at various furnace set point temperatures. Experimental results showed a strong dependency of the load effective thermal conductivity on: (1) load void fraction, (2) internal radiation between parts, and (3) external radiation between parts and furnace enclosure. An assessment of a number of effective thermal conductivity models reported in the literature and developed for packed beds and porous media has been carried out. This assessment led to the development of the present model, which incorporates a new additional temperature difference term that accounts for external radiation and a new generalized characteristic length scale that can be used for parts of any arbitrary geometry. All thermophysical properties of solid and gaseous phases have been considered as functions of the parts temperature. The proposed model is in good agreement, within ±25 %, with the experimental data obtained for the various part geometries, load void fractions, and the surrounding temperatures considered in this investigation.

Studies on elements diffusion of Mn/Co coated ferritic stainless steel for solid oxide fuel cell interconnects application

The spinel structure of manganese cobalt oxide (Mn,Co)3O4 is one of the most promising coatings for solid oxide fuel cell (SOFC) stainless steel interconnects. The stoichiometric Mn1.5Co1.5O4 composition has properties that are preferable to other Mn/Co ratios, for example a higher conductivity and a thermal expansion coefficient that matches the typical steel substrate. However, previous work showed the Mn/Co ratio changes during operation due to the diffusion of Mn from the substrate. The results presented here are on three coatings with different compositions (namely; pure Co, Mn20Co80, and Mn40Co60) with each coating composition deposited to a thickness of 800 nm, 1500 nm, and 3000 nm. The coatings were applied by DC magnetron sputtering and then machine cut into coupons for isothermal annealing at 800 °C in air using a batch-type furnace for 2, 10, 50, 250, and 1000 h. The morphology, chemical composition (including surface and cross sections of the layers) and structures of the oxides formed were analyzed by SEM, EDS and XRD. Analysis of the element diffusion (Mn, Co, Cr, Fe) shown here points to an optimized coating recipe of Mn40Co60.

Cost-Effective Silicon Vertical Diode Switch for Next-Generation Memory Devices

In this letter, a cost-effective vertical diode scheme for next-generation memory devices, including phase-change memories (PCMs), is realized. After the contact formation for diodes with only one mask layer, an amorphous silicon (a-Si) film was deposited within the contacts using SiH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ramp-up ambient in a conventional batch-type furnace in order to minimize the growth of native oxide. A deposition/etch-back/deposition scheme enabled us to achieve robust vertical diodes without any seams or interfacial oxide layer within the vertical diode pillars. Subsequent annealing at 600 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C provided solid-phase epitaxial alignment of the a-Si layer. An ideality factor revealed that the new scheme provided noticeable crystallinity of the silicon diodes. Moreover, the electrical characteristics of the diodes verified that the scheme was suitable for full operation of PCM devices.

Present status and future prospect of coated conductor development and its application inJapan

The current national project on coated conductors using Y-system superconductorshas been carried out over the project period (FY2003–FY2007). In this paper,the current status and the future prospect of this project are reviewed.The high performance tape development group, consisting of Fujikura andSRL-NCCC, has worked on the tape by PLD-REBCO superconducting layers onPLD-CeO2/IBAD-GZO buffered substrates. A high product ofIc and L, higher than 112 166 A m, was achieved in a 368 m–304.8 A GdBCO tape whoseIc value is mostlyabove 350 A/cm in width. The performance under magnetic field was alsoimproved up to 42 A at 3 T in a GdBCO short film with doping ofZrO2. 61 m long GdBCOtape with ZrO2 dopingshowed a high Ic value of 220 A at self field and 30 A at 3 T. On the other hand, another group focusing onlow production cost has worked on TFA-MOD and MOCVD processes. The extremely highIc value of735 A/cm-w was obtained inTFA-MOD films on PLD-CeO2/IBAD-GZO/Hastelloy substrate due to the effect of Ba-poor nominal composition. In effortstowards long tape production by the SWCC group, a 200 m long tape with a highIc valueof 200 A/cm-w was obtained using a batch-type furnace. TheIc × L value of this tape was 40 000 A m, which is the highest value in the world obtained bythe TFA-MOD process. Based on the above achievements in coated conductorprocess development, two new additional goals were set in the project. One is thedevelopment of extremely low cost tape and the other is the development of the basictechnologies for making electric power devices of cables, transformers, motors,current-limiters and cryocoolers. Some of the new investigations have already revealedmarvellous results, such as a 15 kW motor, low AC loss coils, low AC loss cables, etc.

Optimization of Energy Utilization and Productivity of Heat Treating Batch-Type Furnaces

Abstract Due to the energy-intensive nature of the heat treating industry and the recent substantial increase of energy prices, the availability of predictive tools that can be used to optimize heat treatment processes has become a very pressing must. Load configuration (size and arrangement) during batch-type heat treating operations is the main factor that controls the rate of heat transfer between the furnace and the load, and hence it affects energy utilization and productivity of such operations. The main objective of this work is to develop a numerical model that can be used as a predictive tool for determining optimum loading of batch-type furnaces in order to achieve maximum productivity (mass treated per unit time) and minimum energy consumption per unit mass. A numerical model has been developed to simulate heat treatment processes in batch-type furnaces. The model has been validated by comparing numerical results with experimental data collected under laboratory and real-life conditions. Experiments have been carried out at the research facility at TPL as well as at different industrial sites. The paper presents the development and validation of the model as well as case studies of batch heat treatment cycles where best load configurations have been investigated.

In-plane textured oxide buffer layer for the TFA-MOD method on [formula omitted] Ni tapes using MOD process

We developed a low cost process, the so-called all-MOD process, whereby we used MOD to deposit both YBCO and oxide buffer layers on {1 0 0}〈0 0 1〉 Ni tapes. Highly in-plane textured and crack-free Ce–Gd–O (CGO) buffer layers on the cube-textured Ni tapes were achieved by the MOD process. Highly in-plane textured YBCO films on the CGO-buffered Ni tapes were also observed. Long tapes were made by applying a 1 m long CGO buffer layer on the Ni tapes and firing in a batch-type furnace. The CGO films were made by a continuous bead coating process and firing under an Ar–H 2 atmosphere. The 1 m CGO-on-Ni tape was highly in-plane textured. R I(2 0 0) and FWHM of phi-scan values were 88–96% and 7.0–8.5°, respectively. We determined the degree of ( n 0 0)-orientation: R I(n 0 0) [≡I (n 0 0) /{I (n 0 0) +I (m m m) }×100(%)] , where I (n 0 0) and I (m m m) peaks represent the X-ray θ–2 θ scan intensities. These results indicate that buffered Ni tapes made by the MOD process are useful for TFA-MOD fabrication of long-length YBCO coated conductors.

Applications of single-wafer thermal processing to 0.15-μm high-density MROM

Feasibility of single-wafer rapid-thermal process as an alternative to the conventional batch-type furnace process is evaluated on a 0.15-/spl mu/m 128-Mb mask read only memory (MROM) product. Excellent gate oxide integrity and device characteristics are achieved with a single-wafer rapid-thermal process. Superior yield and product reliability by using single-wafer process tool have also been achieved. Shortened process cycle time and better thermal process uniformity by using single-wafer rapid-thermal processing are demonstrated.

Low-resistance polysilicon process in contact application for high density devices

For the lowest resistance, it is required to have the epitaxial silicon contact between the silicon plug and the substrate and good step coverage at the high aspect-ratio contact holes, simultaneously. In this work, a double polysilicon (DPS) deposition technique was proposed for the requirements. The first, thin silicon layer is deposited in a single-wafer process chamber with an in-situ H2-RTP (rapid thermal process) treatment for the epitaxial contact, and the second silicon layer is formed in a batch-type furnace for good step coverage. From chain resistance, Kelvin Rc, and current-voltage (I–V) measurement, the DPS process meets both low resistance and good uniformity, so that it suggests a breakthrough in the small-sized, semiconductor device application.

OS11(6)-25(OS11W0094) Study on Service Performance of Automobile Steel Sheets

Materials with the biggest increase in usage of light-weighting cars and trucks aren't aluminium, magnesium or some other alternative metals. Instead, it is the high strength steel sheets, such as extra-low carbon steels, that have shown the most growth in the light-vehicle market. The continuing emphasis on vehicle mass reduction has driven researchers to investigate the use of thin, high-strength steels in automobiles. Reducing weight by using thinner high strength steel sheets allows the car companies to meet reduced fuel requirements without compromising the size and safety of the cars as well as the buyer's affordability. Extra-low carbons steels, commonly known as interstitial Free (IF) steels have been widely used for automobile plates. IF-steels have also been widely sued in many kinds of products by press deformation particularly of stamped components in automobile application because of their excellent deep-draw ability and high resistance aging. In this study the steel sheets have been prepared by adding Sn (tin), using different content varied from 0.002% to 0.22% mass to other chemical compositions such as Carbon (C), Silicon (Si), Manganese (Mn), Phosphorus (P), Sulfur (S), Aluminium (Al), Nitrogen (N) with almost the same mass percentage. The materials were initially hot-rolled, then cold rolled to 1.4mm thick steel sheets and annealed at 650℃ and 750℃ for 1 minute in laboratory condition by using Batch type furnace. Sheet materials were cut and machined to 30×90mm specimen's longitudinal side parallel with the rolling direction. Curve with 40mm radius was added to each specimen in order to provide stress concentration part for limitation of crack initiation area. All specimen have been tested using the plain bending fatigue-testing machine at 30Hz with capacity of 1.96 Nm. Successive replica observations are performed to observe the fatigue crack initiation and fatigue crack propagation behavior. In addition, the scanning microscope (SEM) was employed for fracture surfaces observation. The main results in this test show that the fatigue strength by 1×(10)^7 cycles increased with increasing Sn (tin) content. The fatigue cracks initiated from the surface and propagated in both intergranular and transgranular mode. The fatigue crack growth rate decreased with increasing tin contents.

The Manufacture of High Permeability Mn-Zn Ferrites by Atmospherical Protect

For the manufacture of high permeability Mn-Zn ferrite cores, the zinc loss from the surface of sintering cores causes poor yield rate of final products. This experiment uses the atmospherical protection to reduce the evaporation of zinc. The control of the oxygen partial pressure and flow rate precisely can reduce the zinc loss about 20% to 35%, but it is not enough to get a good distribution of permeability of products, i.e. the distribution of initial permeability from 12000 to 15000 per products about 14% before atmospherical control and 25% after atmospherical control, respectively. Combination with precise control and zinc vapor compensation can increase the yield rate 9% to 15%. Another experiment to manufacture high permeability Mn-Zn ferrite cores for 15000±30% in a batch type furnace(about 13 Kg / batch), is to use a new engineering method to protect sintering core to avoid vaporizing zinc vapor, the yield rate can be rapidly increased from 25% to 75% and the effective capacity of furnace can be at least twofold. It is successful to manufacture homogeneous and high permeability of MnZn ferrites both increasing the quality of products and decreasing the operating costs.

Structures of high-alumina felt linings

High-alumina felt can be effectively used to make the insulation layers of industrial furnace lining at temperatures up to 1150°C and for the working layers up to 850°C and gas speeds up to 5 m/sec. The most advantageous use of felt is as the working layer of the linings of batch-type furnaces.

高炭素鋼鋼塊の加熱過程における内部亀裂の発生について

Through a series of experiments and theoretidal calculations we disovered that 1·4 t circularingots (400mm_??_×1, 500mm) and 1.7t square ingots (400mm_??_×1, 500mm) of highcarbon-chromium steel suffer cracking due to to thermal stress when heated to the rollingtemperature in a reheating furnace.The results obtained are as follows:(1) To find out the period and the surface-center temperature difference at which theinternal cracking may take place, we heated the ingots at varios heating speeds in a Batchtype furnace. Cracks developed only in the ingots in which transformation had been completed, and whose surface-center temperature difference at the completion of transformationwas over 230°C-240°in calculated value. And this critical temperature difference wasidentical with both of the circular and the spuare ingots.(2) From the inspection of many of the ingots of the above two types which had undergone cracking after heating in a continuous reheating furnace, we could find again thatcracking took place only in the ingots whose core had completed transformation with surfacecentertemperature difference of more than about 240°.Thus we can say that thecontinuous furnace of this type must have the heating capacity smaller than 30t/h to preventcracking.(3) With several typical examples of heating curves of ingots in the continuous furnace, wemade calculations of the thermal stress which occurs inside the ingots and found that elasticplasticstress and plastic strain increase violently at the core of the ingot when the corecompletes the transformation. But in all the calculations of rapid heating the maximumthermal stress value remains in this case constant at 0.1kg/mm2 with the exception of theincrease of plastic strain.On the other hand, if the increase of plastic flow delays in proportion to the increase ofplastic strain and strain rate because the plastic flow is retarded by the triaxial tension stressesof the core part, the increase of the stress in the flow state becomes greater than thefracture stress of 13kg/mm2 and consequently it causes thermal stress crackings.Thus we can explain the occurrence of thermal stress crackings in rapid heating.(4) From the results of the above experiments and calculations, we could devise the wayof heating effectively and without cracking the ingots which are very liable to crack likethose of high-carbon-chromium steel.By the use of this method we are now able to obtaina heating capacity of more than 40t/h without any crackings.

General purpose batch-type furnace

General purpose batch-type furnace

Computer Control for Optimum Performance of a Batch-type Furnace

Computer Control for Optimum Performance of a Batch-type Furnace