Earticle

반도체 소자의 크기가 작아지고 소재가 다양해지면서 식각 공정의 정밀도, 소재 종류에 따른 선택성, 공 정 신뢰성이 더욱 중요해지고 있습니다. 포토리소그래피는 반도체 공정에서 정밀한 패턴을 구현하는 데 핵심 공정 이며, 이는 고밀도 반도체 소자를 가능하게 합니다. 고밀도 반도체 소자는 기능과 성능이 향상되며, 고밀도 반도체 소자 공정은 공정 신뢰성 확보가 중요합니다. 본 연구는 반도체 소자의 목표 임계 치수와 웨이퍼 공정 신뢰성을 고려하여, 광식각 공정의 노출 시간과 현상 시간을 최적화하는 방법을 제시합니다. 이러한 최적화 기술은 에칭 및 증착과 같은 다른 반도체 공정에도 적용되어 전체 공정 효율성과 신뢰성을 향상시킬 수 있습니다.

Photolithography is essential in semiconductor manufacturing for defining intricate patterns with high precision, enabling densely packed integrated circuits crucial for modern electronics. Its high resolution ensures the functionality and performance of components, while its repeatability and scalability make it cost-efficient for mass production. This study presents a method to optimize exposure and development times in photolithography, considering target critical dimension and wafer reliability. These optimization techniques can also be applied to other semiconductor processes like etching and deposition, enhancing overall manufacturing efficiency and reliability.

Lactic acid is an important chemical that can be used to synthesize biodegradable polymers, such as polylactic acid (PLA) and its copolymers. Precipitation was employed to recover lactic acid from a calcium lactate solution using sulfuric acid. In this study, we optimized process parameters of precipitation to obtain a high yield and purity of lactic acid from a calcium lactate solution. Also, we observed the influence of the main process parameters on precipitate formation during the course of precipitation using a video microscope. The optimal calcium lactate/sulfuric acid molar ratio and pH were 1/1 and 6.8, respectively. Also, the effect of mixing method on the efficiency of precipitation and the formation of precipitate were evaluated. When the sample was mixed continuously after adding sulfuric acid, lactic acid was obtained in high yield. By mixing the sample, we were able to significantly reduce the precipitation time, the length of which has been a problem inherent in the conventional precipitation process. The yield of recovered lactic acid was 92% with a purity of 71%.

In present research work the effect of insert nose radius and machining parameters including cutting speed, feed rate and depth of cut on surface roughness(Ra) and material removal rate(MRR) in a turning of HSS(M2) are investigated using the Taguchi method and ANOVA. A three level, four parameter design of experiment,L9 orthogonal array using Minitab 14 software, the signal-to-noise (S/N) ratio is employed to study the performance characteristics in the turning of HSS(M2) by taking nose radius of Tin coated carbide inserts tool of 0.4,0.8 and 1.2 mm on CNC turning centre. The analysis of variance (ANOVA) is applied to study the percentage contribution of each machining parameters while CNCturning of HSS (M2) material. The all experimental trials are conducted in dry machining environment and at a constant spindle speed 2800 rpm.The results are verified by taking confirmation experiments. The present investigation indicates that feed rate and nose radius are the most significant factors in case of material removal rate and surface roughness for turning of HSS (M2) material.

In order to optimize the process parameters of ceramic powder compaction, a process simulation was first performed using a finite element method. In the finite element analysis, a quasi-random multi-particle array was introduced for modeling the non-periodic and randomly scattered powder particles with initially-low relative densities. Homogenization theory was employed to find the equivalent material properties associated with various porosities. The size of Al2O3 particles, amplitude of the cyclic compaction pressure, and friction coefficient among powder particles were chosen as process parameters. Finite element analysis results show that relative density becomes bigger as the process variables become smaller. Next, a regression model was found by using the response surface method, based on the results of the finite element analysis. Then, the optimal conditions of the process parameters providing the highest relative density were pursued by employing a grid search method.

This study focuses on optimizing the underwater friction stir welding (UFSW) process parameters for AA8011 reinforcedwith 5 wt% silicon carbide (SiC) particles. The primary goal is to enhance the mechanical properties of the weld joints bysystematically investigating the influence of rotating speed (A), traverse speed (B), and tool pin profile (C). The experimentalsetup utilized a Taguchi L9 orthogonal array, and optimization was performed using multi-criteria decision-making (MCDM)techniques, specifically MEthod based on the Removal Effects of Criteria (MEREC) and Measurement of Alternatives andRanking according to COmpromise Solution (MARCOS). Mechanical properties such as tensile strength (TS), hardness(HV), and impact strength (IS) were evaluated alongside microstructural analysis. The ideal welding parameters?1000rpm rotational speed, 20 mm/s travel speed, and hexagonal tool pin?were determined using MCDM approaches (MERECand MARCOS), resulting in a maximum tensile strength of 108.88 MPa, hardness value of 98, and impact strength of 10 J. ANOVA indicated that the tool profile was the most significant factor, accounting for 81.44% of the joint quality, followedby rotational speed at 13.19% and traverse speed at 4.69%. Microstructural analysis revealed enhanced grain refinementand uniform material flow under optimal conditions, contributing to the improved mechanical performance. The findingsunderscore the critical role of parameter optimization in achieving high- performance weld joints and demonstrate theeffectiveness of UFSW for producing durable and reliable composite materials. These insights provide a valuable foundationfor advancing welding practices in aerospace, marine, and automotive industries.

Friction stir welding (FSW) grabs more attention since the past decade among the researchers worldwide due to its excellentcharacteristics such as no emission of fumes, no filler material, comparatively economical and so on. Friction stir weldingis effectively used in bringing better joint without any appreciable defects in light materials such as Aluminium, Magnesiumetc., Experiments in FSW of materials with high density such as steel, copper alloys etc., have also been tried out. Theselection of proper welding parameters determines a good weldment. In this work, Aluminium matrix hybrid compositewas manufactured through stir casting with the matrix AA7010 and reinforcements SiC and Al2O3. The hybrid compositeworkpieces were subjected to friction stir welding process by varying the process parameters such as tool rotation speed,welding speed and axial force using Taguchi L27 orthogonal array. Tensile strength of FS welded composite was examinedand regression analysis was done. Genetic Algorithm technique was used to optimize the weld tensile strength within thedesign space of 53 = 125 alternatives of parametric combinations. The study focuses on the improvement of the tensilestrength of the welded specimens.

A microstructure analysis is carried out to optimize the process parameters of a randomly oriented discrete length hybrid carbon fiber reinforced carbon matrix composite. The composite is fabricated by moulding of a slurry into a preform, followed by hot-pressing and carbonization. Heating rates of 0.1, 0.2, 0.3, 0.5, 1, and $3.3^{\circ}C/min$ and pressures of 5, 10, 15, and 20 MPa are applied during hot-pressing. Matrix precursor to reinforcement weight ratios of 70:30, 50:50, and 30:70 are also considered. A microstructure analysis of the carbon/carbon compacts is performed for each variant. Higher heating rates give bloated compacts whereas low heating rates give bloating-free, fine microstructure compacts. The compacts fabricated at higher pressure have displayed side oozing of molten pitch and discrete length carbon fibers. The microstructure of the compacts fabricated at low pressure shows a lack of densification. The compacts with low matrix precursor to reinforcement weight ratios have insufficient bonding agent to bind the reinforcement whereas the higher matrix precursor to reinforcement weight ratio results in a plaster-like structure. Based on the microstructure analysis, a heating rate of $0.2^{\circ}C/min$, pressure of 15 MPa, and a matrix precursor to reinforcement ratio of 50:50 are found to be optimum w.r.t attaining bloating-free densification and processing time.

EN25 Steel possesses higher mechanical strength and corrosion resistance. Due its excellent properties, this work material isused in heavy duty driver shaft. Turning of EN25 steel is complex and determination of optimal turning process parametersis highly required to improve the cost effectiveness. In this research work coated carbide insert are used as the cuttingtool material to turn EN25 steel in the CNC machine. The turning process parameters considered in this work are cuttingspeed, feed rate, depth of cut and type of the tool. The responses considered in this work are Tool life, surface roughnessand material removal rate. Multi criteria decision making is a new decision making method which is used to rank the bestalternatives among the given optimal solutions. In this work the technique for order performance by similarity to idealsolution (TOPSIS) technique is used for solving the multi criteria decision problem. ANOVA analysis is also used to checkthe adequacy of the model.

A study on water-based epoxy coated on mild steel using the electroplating method was conducted to optimize the process parameters for dry film thickness to achieve superior paint quality at optimal cost in an automotive plant. The regression model was used to adjust various parameters such as electrode voltage, bath temperature, processing time, non-volatile matter, and surface area to optimize the dry film thickness. The average dry film thickness computed using the model was in the range of 15 - 35 ㎛. The error in the computed dry film thickness with reference to the experimentally measured dry film thickness value was - 0.5809%, which was well within the acceptable limits of all paint shop standards. Our study showed that the dry film thickness on mild steel was more sensitive to electrode voltage and bath temperature than processing time. Further, the presence of non-volatile matter was found to have the maximum impact on dry film thickness.

In auto ancillary fabrication industry, GMAW is a very useful & important welding process and EN10025 S 235 Grade is common material used for manufacturing of two wheeler chassis. This research gives the detail influence of welding process parameters such as welding current, welding voltage, wire speed on the penetration in EN10025 S 235 Grade mild steel material. The experimentation of this research has been carried out by using three factors, three level Taguchi DOE method. To analyze & optimize the welding parameters & characteristics, analysis of variance, L9 orthogonal array & signal to noise ratio are used. Length of Penetration in addition to the depth of penetration is major concern in fillet welded joints, as the penetration decides the strength of the welded joint. After analysis of penetration in all 9 welded samples, optimize parameters readings verified & found probability value within 0.05.From this research it is come to know that welding current & welding voltage is major parameters which affects the penetration in welded joints.

Soft magnetic powder materials are used throughout industries such as motors and power converters. When manufacturing Fe-based soft magnetic composites, the size and shape of the soft magnetic powder and the microstructure in the powder are closely related to the magnetic properties. In this study, Fe-Si-Al-P alloy powders were manufactured using various manufacturing process parameter sets, and the process parameters of the vacuum induction melt gas atomization process were set as melt temperature, atomization gas pressure, and gas flow rate. Process variable data that records are converted into 6 types of data for each powder recovery section. Process variable data that recorded minute changes were converted into 6 types of data and used as input variables. As output variables, a total of 6 types were designated by measuring the particle size, flowability, apparent density, and sphericity of the manufactured powders according to the process variable conditions. The sensitivity of the input and output variables was analyzed through the Pearson correlation coefficient, and a total of 6 powder characteristics were analyzed by artificial neural network model. The prediction results were compared with the results through linear regression analysis and response surface methodology, respectively.

In auto ancillary fabrication industry, GMAW is a very useful & important welding process and EN10025 S 235 Grade is common material used for manufacturing of two wheeler chassis. This research gives the detail influence of welding process parameters such as welding current, welding voltage, wire speed on the penetration in EN10025 S 235 Grade mild steel material. The experimentation of this research has been carried out by using three factors, three level Taguchi DOE method. To analyze & optimize the welding parameters & characteristics, analysis of variance, L9 orthogonal array & signal to noise ratio are used. Length of Penetration in addition to the depth of penetration is major concern in fillet welded joints, as the penetration decides the strength of the welded joint. After analysis of penetration in all 9 welded samples, optimize parameters readings verified & found probability value within 0.05.From this research it is come to know that welding current & welding voltage is major parameters which affects the penetration in welded joints.

The friction stir welding of AA1100 aluminium alloy is experimentally investigated and analysed in this work. The weld qualityof FSW is analysed and optimized for the welding process parameters such as weld speed, tool rotational speed, tool pingeometry and axial load in this work. The tensile strength of the welded specimen is considered as the response and responsesurface methodology is used here to establish a relationship between the factors and the response. In this work a mathematicalmodel using the multiple regression equations for friction stir welded aluminium plates are established and analysed usingANOVA. It is observed that the tool pin shape with square geometry contributes to higher tensile strength when comparedto the other tool pin profiles. Also it is seen that as the feed and axial load increases there is an increase in tensile strength ofthe welded specimen.

The aim of this research is to improve the Resistance Spot Welding (RSW) process characteristics of AISI SS316L joints ontensile shear load (TSL). The RSW process parameters like electrode diameter of 6mm to 8mm, welding current of 7 kA to9 kA, heating cycle periods of 7 to 9 are selected. The 2 mm sheet thickness has been selected for the welding trials and tensileshear test has been involved for all the trials for the purpose of identifying the TSL. Taguchi optimization technique is usedfor design the experiment with the help of Minitab software. It is observed that maximum TSL of 16 kN is observed by settingthe parameters at 6mm electrode diameter, 9 kA welding current and heating cycles of 9. The ANOVA table confirms thatwelding current majorly affects the quality of weld and all the trials are observed with interfacial failure.

Stainless steel is used in automobile muffler and exhaust systems. However, in comparison with other steels it has a high thermal expansion rate and low thermal conductivity, and undergoes excessive thermal deformation after welding. To address this problem, we evaluated the use of arc brazing in place of welding for the processing of an exhaust system, and investigated the parameters that affect the joint characteristics. Muffler parts STS439 and hot-dipped Al coated steel were used as test specimens, and CuAl brazing wire was used as the filler metal for the cold metal transfer (CMT) welding machine, which is a low heat input arc welder. In addition, a Box-Behnken design of experiment was used, which is a response surface methodology. The main process parameters (current, speed, and torch angle) were used to determine the appropriate welding quality and the mechanical properties of the brazing part was evaluated at the optimal welding condition. The optimal processing condition for arc brazing was 135A current, 51cm/min speed and $74^{\circ}$ torch angle. The process was applied to an actual exhaust system muffler and the prototype was validated by thermal fatigue, thermal shock, and endurance limit tests.

Stainless steel is used in automobile muffler and exhaust systems. However, in comparison with other steels it has a high thermal expansion rate and low thermal conductivity, and undergoes excessive thermal deformation after welding. To address this problem, we evaluated the use of arc brazing in place of welding for the processingof an exhaust system, and investigated the parameters that affect the joint characteristics. Muffler parts STS439 and hot-dipped Al coated steel were used as test specimens, and CuAl brazing wire was used as the filler metal for the cold metal transfer (CMT) welding machine, which is a low heat input arc welder. In addition, a Box-Behnken design of experiment was used, which is a response surface methodology. The main process parameters (current, speed, and torch angle) were used to determine the appropriate weldingquality and the mechanical properties of the brazing part was evaluated at the optimal welding condition. The optimal processing condition for arc brazing was 135A current, 51cm/min speed and 74° torch angle. The process was applied to an actual exhaust system muffler and the prototype was validated by thermal fatigue, thermal shock, and endurance limit tests.

High strength and less in weight has evidenced the high application of Aluminum 7075 in industry. Present research ofAluminum 7075 has highly aimed for surface modification for better wear rate and friction resistance. This work isparticularly carried out to modify the surface of aluminum 7075 with high mechanical properties and wear for high strengthapplications. The work contains development of AA7075 T6 with prearranged compositions of SiC & Gr by using Frictionstir processing. First, Fabrication of AA7075 with 10wt.% of SiC and 5wt.% of Gr was done with single, double and triplepass technique. Secondly, Different tests were carried out to identify suitable material fabrication technique and mechanicalcharacteristics. Based on the experimental results, 3pass FSP AA7075/SiC & Gr specimen offered better results with 156HVhardness, 268MPa tensile stress were found and process parameters are optimized.

The quality of metal components manufactured by laser-based additive manufacturing technologies is governed by the process parameters. Moreover, the process parameters differ depending on the material used. In particular, direct energy deposition (DED) technology is vulnerable to the control of external environmental variables, and there are many process variables, such as powder characteristics and laser parameters, and thus many tests are required to de?termine the optimal parameters. In this study, an experiment was conducted to derive the conformity criterion of the DED process for metal powder (STS304L). First, the effects of laser energy output, laser header moving speed, powder feed rate, and gas feed rate on the DED process were studied. The experimental results showed that the dep?osition height decreased as the laser header moved faster and that the dilution ratio and the width of the heat-affected zone depended on the laser power and powder feed rate. Specimens were printed based on the process parameter values determined in the experiment, and tensile tests were conducted to analyze their mechanical performance.