CMP 패드 두께 프로파일 측정 장치 및 방법에 관한 연구

이태경,김도연,강필식,Lee, Tae-kyung,Kim, Do-Yeon,Kang, Pil-sik 한국산업융합학회 2020 한국산업융합학회 논문집 Vol.23 No.6

The chemical mechanical planarization (CMP) is a process of physically and chemically polishing the semiconductor substrate. The planarization quality of a substrate can be evaluated by the within wafer non-uniformity (WIWNU). In order to improve WIWNU, it is important to manage the pad profile. In this study, a device capable of non-contact measurement of the pad thickness profile was developed. From the measured pad profile, the profile of the pad surface and the groove was extracted using the envelope function, and the pad thickness profile was derived using the difference between each profile. Thickness profiles of various CMP pads were measured using the developed PMS and envelope function. In the case of IC series pads, regardless of the pad wear amount, the envelopes closely follow the pad surface and grooves, making it easy to calculate the pad thickness profile. In the case of the H80 series pad, the pad thickness profile was easy to derive because the pad with a small wear amount did not reveal deep pores on the pad surface. However, the pad with a large wear amount make errors in the lower envelope profile, because there are pores deeper than the grooves. By removing these deep pores through filtering, the pad flatness could be clearly confirmed. Through the developed PMS and the pad thickness profile calculation method using the envelope function, the pad life, the amount of wear and the pad flatness can be easily derived and used for various pad analysis.

Design of Roll Profile in Shape Rolling of an Irregular Angle Bar by the Modified Butterfly Method

이상진,김병민,김성민,고대철 한국정밀공학회 2013 International Journal of Precision Engineering and Vol.14 No.1

The roll profile of an angle bar is generally designed by the butterfly method however, the design of the roll profile of an irregular angle bar requires a special rule to take a tapered leg or a protrusion on the leg into account. For this purpose, the butterfly method has been modified in this study to design the roll profile for an irregular angle bar by introducing the equivalent leg thickness. The thickness of the tapered leg or the leg with the protrusion is changed into the equivalent leg thickness to calculate the thickness and length of the leg for the next pass. Shape rolling processes for inverted and unequal angle bars are designed by the proposed method,and its effectiveness is verified by FE-simulation and experiments using plasticine. In addition, the design method is applied to the shape rolling of more complicated irregular angle bar, such as an automotive door hinge. The cross-sectional shapes at each pass are compared with those obtained from the experiment using steel. The results of FE-simulation and experiment show that the proposed design method effectively designs the roll profile for an irregular angle bar, leading to accurate shape and dimensions in the final product within the allowable tolerance of ± 0.4 mm in thickness and ± 1.5 mm in length. Therefore, the proposed design method can be widely used to design roll profiles for variously shaped angle bars in industrial fields.

원호형 차륜답면형상(안) 설계 및 현차시험 결과

허현무,이찬우,구동회,권성태 한국철도학회 2004 한국철도학회논문집 Vol.7 No.2

The rolling-stocks on conventional line have suffered wheel problems due to the incompatibility between wheel and track condition. Especially, The 1:40 coned wheel profile’s wear is very severe and these increase wheel maintenance cost. Thus we designed several arc-type wheel profiles coned 1:/20 to reduce the wheel flange wear and analyzed the dynamic performance of designed profiles. Tests carried out in service line to analyse the dynamic performance and verify the wear reduction for two cases of profiles. Test results shows the equal level of dynamic performance and the improvement of wheel flange wear compared with the conical wheel profile coned 1:40.

원호형 차륜답면형상(안) 설계 및 현차시험 결과

허현무(Hyun-Moo Hur),권성태(Sung-Tae Kwon),이찬우(Chan-Woo Lee),구동회(Dong-Hoe Goo) 한국철도학회 2004 철도저널 Vol.7 No.2

The rolling-stocks on conventional line have suffered wheel problems due to the incompatibility between wheel and track condition. Especially, The 1:40 coned wheel profile's wear is very severe and these increase wheel maintenance cost. Thus we designed several arc-type wheel profiles coned 1:/20 to reduce the wheel flange wear and analyzed the dynamic performance of designed profiles. Tests carried out in service line to analyse the dynamic performance and verify the wear reduction for two cases of profiles. Test results shows the equal level of dynamic performance and the improvement of wheel flange wear compared with the conical wheel profile coned 1:40.

Thermoelastic solutions for annular disks with arbitrary variable thickness

Zenkour, Ashraf M. Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.24 No.5

This article presents a unified analytical solution for the analysis of thermal deformations and stresses in elastic annular disks with arbitrary cross-sections of continuously variable thickness. The annular disk is assumed to be under steady heat flow conditions, in which the inner surface of the annular disk is at an initial temperature and the outer surface at zero temperature. The governing second-order differential equation is derived from the basic equations of the thermal annular disks and solved with the aid of some hypergeometric functions. Numerical results for thermal stresses and displacement are given for various annular disks. These disks include annular disks of thickness profiles in the form of general parabolic and exponential functions. Additional annular disks with nonlinearly variable thickness and uniform thickness are also included.

Improvement of Lubrication Characteristics in Fuel Injection Pump for Medium-Speed Diesel Engines: Part I - Application of Profile Shape

홍성호 한국트라이볼로지학회 2015 한국윤활학회지(윤활학회지) Vol.31 No.5

In this research, effects of profile changes of stem section of the plunger on the lubrication characteristics of a fuel injection pump (FIP) were evaluated by hydrodynamic lubrication analysis. The clearance between plunger and barrel was divided into two regions, head and stem. The head was not involved in preventing a decrease of fuel oil pressure. So, research efforts were focused on both edges of the plunger’s stem. The two -dimensional Reynolds equation was used to evaluate lubrication characteristics with variations in viscosity, clearance and profile for a laminar, incompressible, unsteady-state flow. Moreover, the equilibrium equation of moment and forces in the vertical and horizontal directions were used to determine the motion of the plunger. The equations were discretized using the finite difference method. Lubrication characteristics of the FIP were investigated by comparing the dimensionless minimum film thickness, or film parameter, which is the ratio of minimum film thickness to surface roughness. Through numerical analyses, we showed that the profile of the lower edge of the stem had no effect on lubrication characteristics, but the profile of the upper edge had a significant influence on lubrication characteristics. In addition, changes in the profile were more effective in improving lubrication characteristics under low viscosity conditions. In this research, effects of profile changes of stem section of the plunger on the lubrication characteristics of a fuel injection pump (FIP) were evaluated by hydrodynamic lubrication analysis. The clearance between plunger and barrel was divided into two regions, head and stem. The head was not involved in preventing a decrease of fuel oil pressure. So, research efforts were focused on both edges of the plunger’s stem. The two -dimensional Reynolds equation was used to evaluate lubrication characteristics with variations in viscosity, clearance and profile for a laminar, incompressible, unsteady-state flow. Moreover, the equilibrium equation of moment and forces in the vertical and horizontal directions were used to determine the motion of the plunger. The equations were discretized using the finite difference method. Lubrication characteristics of the FIP were investigated by comparing the dimensionless minimum film thickness, or film parameter, which is the ratio of minimum film thickness to surface roughness. Through numerical analyses, it is found that the profile of the lower edge of the stem had no effect on lubrication characteristics, but the profile of the upper edge had a significant influence on lubrication characteristics. In addition, changes in the profile were more effective in improving lubrication characteristics under low viscosity conditions.

방사선투과필름에서 Density Profile 을 이용한 배관의 두께 평가

이성식,장병규,김영환 한국비파괴검사학회 2002 한국비파괴검사학회지 Vol.22 No.5

내부가 비어 있거나 유체로 절반 채워진 보온 및 비보온 배관에 대해 방사선 조사 방향에 따른 투과두께와 농도 변화를 전산 시뮬레이션 하였다. 결과적으로 내부가 비어있는 배관의 경우 투과필름에서 농도 변화가 연속적이며 대칭적인 반면, 유체가 절반 채워진 배관의 경우는 방사선 조사 방향에 따라 농도 변화가 비대칭적이며 크게 달라질 수 있음을 알았다. 인공 결함을 가공한 탄소강 배관 시편을 방사선원 Ir-192로 방사선투과시험 한 뒤 농도 변화를 측정하고 이론적으로 계산한 농도 변화와 비교한 결과 산란 방사선에 의한 영향이 큰 가장자리를 제외한 부분에서는 농도 변화를 이용한 두께 평가가 가능함을 확인하였다. The computer simulation has been done for non-insulated and insulated pipes which are vacant or half filled with liquid. The simulation-results showed that the density profile on the radiograph is continuous and symmetrical around the center of pipe in the case of vacant pipe. On the other hand the density profiles are not symmetrical and depend on geometrical setting for radiography in the case of half filled pipes. Finally, experimental testing on a non-insulated carbon steel pipe with artificial notches of different depth is carried out using Ir-192 and industrial film. Comparing the measured density profile on the radiograph to the the calculated one, it has been shown that it is possible to evaluate thickness variation by measuring density profile on a radiograph.

Facial soft tissue thickness among skeletal malocclusions: is there a difference?

Kamak, Hasan,Celikoglu, Mevlut The Korean Association Of Orthodontists 2012 대한치과교정학회지 Vol.42 No.1

Objective: The purpose of this study was to determine the soft tissue thickness of male and female orthodontic patients with different skeletal malocclusions. Methods: Soft tissue thickness measurements were made on lateral cephalometric radiographs of 180 healthy orthodontic patients with different skeletal malocclusions (Class I: 60 subjects, Class II: 60 subjects, Class III: 60 subjects). Ten measurements were analyzed. For statistical evaluation, one-way ANOVA and Kruskal-Wallis tests were performed. Least significant difference (LSD) and Dunnet T3 post hoc tests were used to determine the individual differences. Results: Soft tissue thicknesses were found to be greater for men than for women. Statistically significant differences among the skeletal groups were found in both men and women at the following sites: labrale superius, stomion, and labrale inferius. The thickness at the labrale superius and stomion points in each skeletal type was the greatest in Class III for both men and women. On the other hand, at the labrale inferius point, for both men and women, soft tissue depth was the least in Class III and the greatest in Class II. Conclusions: Soft tissue thickness differences among skeletal malocclusions were observed at the labrale superius, stomion, and labrale inferius sites for both men and women.

Calculation of Tooth Thickness Errors and Its Adjustment on Meshing Backlash of Harmonic Drive

Congbin Yang,Honglie Ma,Tao Zhang,Jigui Zheng,Zhifeng Liu,Qiang Cheng 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.2

Meshing backlash mainly determines the transmission accuracy of harmonic drive, which is an important index in design. In this paper, a design method for short tooth involute profile is proposed. By intercepting part of the tooth profile, meshing interference of the addendum can be effectively avoided. Based on the dimensions of over pins of circular spline and flexspline, a calculation method of tooth thickness deviation is proposed, and the positive and negative tooth thickness deviation are defined. Involute functions need not be calculated by this method, which simplifies the solution process. By discretizing the teeth profile points of circular spline and flexspline, a calculation method of time-varying backlash is proposed, the variation of backlash in meshing in and out is analyzed, and the influence law of tooth thickness deviation on backlash is studied. On this basis, an algorithm for adjusting the radial deformation to compensate for the backlash is proposed. The results show that the excessive backlash in the meshing area can be reduced by increasing the radial deformation. When meshing interference occurs, the interference-free meshing can be realized by decreasing the radial deformation.

Atmospheric thickness and vertical structure properties in wintertime precipitation events from microwave radiometer, radiosonde and wind profiler observations

Kim, Dong‐,Kyun,Lee, Dong‐,In John Wiley Sons, Ltd 2015 Meteorological applications Vol.22 No.3

<P><B>ABSTRACT</B></P><P>With a focus on the properties of atmospheric thickness, temporal variations of various atmospheric quantities at isobaric levels measured and retrieved from microwave radiometer (MWR) and radiosonde soundings were investigated for precipitation events during the winter of 2011 near Seoul, Korea. Wind profiler analyses were performed additionally for examining the returned radar power signal and Doppler velocity characteristics of the vertical structure. It was found that there exists a lead period of 9 to 12 h that shows little change (almost no increase) in the 1000–850 hPa thickness before precipitation. Between snow and rain events, thermodynamic characteristics were similar at lower levels but were noticeably different at upper levels, showing their dependence on the cloud‐top height and updraft intensity. Higher correlation in thickness and temperature between the MWR and radiosonde data was found at lower levels than upper, suggesting that the lead period of the 1000–850 hPa thickness as shown by the MWR is reliable in this study. The vertical structure and precipitation properties analysed from wind profiler observations showed close agreement with MWR retrievals of precipitable water vapour and liquid water content, indicating the effectiveness of the wind profiler as a complementary tool in MWR studies.</P>