• Tribology and Lubricants
• /
• v.40 no.2
• /
• pp.47-53
• /
• 2024

Surface topography plays a decisive role in determining the performance of several precision components. In particular, the surface roughness of semiconductor devices affects the precision of the circuit. In this regard, the surface topography of a given surface needs to be appropriately assessed. Typically, the average roughness is used as one of the main indicators of surface finish quality because it is influenced by both dynamic and static parameters. Owing to the increasing demand for such accurate and reliable surface measurement systems, studies are continuously being conducted to understand the parameters of surface roughness and measure the average roughness with high reliability. However, the differences in the measurement methods of surface roughness are not clearly understood. Hence, in this study, the surface roughness of the back of a silicon wafer was measured using both contact and noncontact methods. Subsequently, a comparative analysis was conducted according to various surface roughness parameters to identify the differences in surface roughness depending on the measurement method. When using a 3D laser confocal microscope, even smaller surface asperities can be measured compared with the use of a 3D profiler. The results are expected to improve the understanding of the surface roughness characteristics of precision components and be used as a useful guideline for selecting the measurement method for surface topography assessment.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.474-480
• /
• 2002

Aspheric optical lenses and mirrors are widely used in recent. It is more difficult to manufacture and measure the aspherical optics compared to conventional spherical ones. The interferometric optical test is common for the measurement of spherical optical surface. But the application of the interferometry to the measurement of aspheric surface is difficult because it needs a precise null corrector and very careful environmental conditions such as keeping constant temperature, humidity, atmospheric pressure and vibrations. To enhance productivity of optics manufacturing on-machine measurement and correction has been developed in this study. For practical applications, robustness of the measurement method to environments is more important. For the purpose an optical OMM(On-Machine Measurement) system has been developed using Shack-Hartmann test which has robustness to the environment. The wavefront has been reconstructed from the measured data using the primary aberration polynomial function by least square fitting. The measured result of the developed only system gives the maximum deviation only in 200 nm from the result measured by a commercial Fizeau interferometer Wyko 6000.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.10a
• /
• pp.71-76
• /
• 2001

In the surface measurement system using touch probe, probe radius compensation is a key factor for accuracy. In this paper we investigate methods for compensating probe radius so that the surface equation for an "unknown surface" can be efficiently derived. The developed algorithm derives the surface equation by the iterative procedure of estimation, verification, and modification . Since the procedure is applied only for the surface region exceeding the tolerance limit, an accurate surface equation can be obtained with less computation and measurement point. The validity and effectiveness of the algorithm was tested by numerical simulations. The results convinced us that the develop algorithm can be used for surface measurement and tool path planning for NC machining.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.115-118
• /
• 2005

A workpiece with a large surface area is likely to be uneven due to form error and waviness. These geometric disturbances can cause inaccurate micro shapes to be formed when micro features are micro-grooved into the surface and cause the resulting workpiece to fail to function as desired. Thus, real-time measurement and compensation is required to guarantee the form accuracy of micro features while machining a workpiece with a large surface area. In this study, a method is suggested for real-time measurement of geometric error for the micro grooving of a large flat surface using a laser displacement sensor. The measurements are demonstrated for the workpieces with large surface areas and the experimental results show that the waviness and form error are well detected.

• The Mathematical Education
• /
• v.58 no.2
• /
• pp.283-298
• /
• 2019

Among the measurement attributes included in the elementary school mathematics curriculum, perimeter, area, volume and surface area are intensively covered in fifth and sixth graders. However, not much is known about the level of student performance and difficulties in this area. The purpose of this study is to examine the understanding and performance of sixth-grade elementary school students on some ideas of measurement and ultimately to give some suggestions for teaching measurement and the development of mathematics textbooks. For this, diagnosis questions were developed in relation to the following parts: measurement of perimeter and area of plane figure, measurement of surface area and volume of solid figure, and the relationships between perimeter and area, and the relationships between surface area and volume. The performances of 95 sixth graders were analyzed for this study. The results showed children's low performance in the measurement area, especially measurement of perimeter and surface area, and relationship of the measurement concepts. Finally, we proposed the introduction order of the measurement concepts and what should be put more emphasis on teaching measurement. Specifically, it suggested that we consider placing a less demanding concept first, such as the area and volume, and dealing more heavily with burdensome tasks such as the perimeter and surface area.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.255-258
• /
• 1995

Surface profile is an important paramerer to evaluate accuracy of machined worpiece. It is necessary to acquire this data by in-process measurement. Recent researchers have introduced Machine Vision technique to achieve it. But it is difficult to apply it to industry field yet. In this study, in-process measuring system of surface profile is developed using CCD camera. The effect of illuminance according to incident angle is investigated and surface profile from surface tester and illuminance graph are compared experimentally.

• 보존과학연구
• /
• s.20
• /
• pp.21-47
• /
• 1999

According to damage of papers by the chemical cause, papers become to acidify. Among the 3 kinds of method measuring the acidity of paper, one was nondestructive method measuring the surface of the paper by flat type electrode and the others were destructive methods measuring directly by cold water extract method and hot water extract method. In case of the cellulolytic cultural properties, the latter methods were not applied because those methods must bedissociated papers. To measure the paper acidity nondestructively, we investigated the correlation of the nondestructive method and the destructive methods. The conclusions are as follows. 1) In the relationship of the cold water extract method and the hot water extract method, It was indicated that the pH measured by the hot water extract method was high quality printing paper 0.08, rough printing paper 0.13, and Korean paper 0.29 higher than that by the cold water extract method.2) In the relationship of the cold water extract method and the surface measurement method, It showed that the pH value measured by the cold water extract method was high quality printing paper 1.86, rough printing paper 0.80,and Korean paper 0.58 higher than value that by the surface measurement.3) In the relationship of the hot water extract method and the surface measurement method, It showed that the pH value measured by the hot ABSTRACT water extract method was high quality printing paper 1.78, rough printing paper 0.66, and Korean paper 0.29 higher than that by the surface measurement. From the above-mentioned results, the pH value measured by the surface measurement was need to high about 1.78∼1.86 in high quality printing paper, 0.66-0.80 in rough printing paper, and 0.29∼0.58 in Korean paper and the surface measurement with flat type electrode was very available to measure the acidity of Korean papers actually.

• 보존과학연구
• /
• s.20
• /
• pp.49-64
• /
• 1999

According to damage of papers by the chemical cause, papers become to acidify. Among the 3 kinds of method measuring the acidity of paper, one was nondestructive method measuring the surface of the paper by flat type electrode and the others were destructive methods measuring directly by cold water extract method and hot water extract method. In case of the cellulolytic cultural properties, the latter methods were not applied because those methods must bedissociated papers. To measure the paper acidity nondestructively, we investigated the correlation of the nondestructive method and the destructive methods. The conclusions are as follows. 1) In the relationship of the cold water extract method and the hot water extract method, It was indicated that the pH measured by the hot water extract method was high quality printing paper 0.08, rough printing paper 0.13, and Korean paper 0.29 higher than that by the cold water extract method.2) In the relationship of the cold water extract method and the surface measurement method, It showed that the pH value measured by the cold water extract method was high quality printing paper 1.86, rough printing paper 0.80,and Korean paper 0.58 higher than value that by the surface measurement.3) In the relationship of the hot water extract method and the surface measurement method, It showed that the pH value measured by the hot ABSTRACT water extract method was high quality printing paper 1.78, rough printing paper 0.66, and Korean paper 0.29 higher than that by the surface measurement. From the above-mentioned results, the pH value measured by the surface measurement was need to high about 1.78∼1.86 in high quality printing paper, 0.66-0.80 in rough printing paper, and 0.29∼0.58 in Korean paper and the surface measurement with flat type electrode was very available to measure the acidity of Korean papers actually.

• 한국초전도학회:학술대회논문집
• /
• v.10
• /
• pp.173-178
• /
• 2000

A prototype for a highly sensitive, automated measurement system for the microwave surface resistance of high-T$_c$ superconductor films was set up, and tested by measuring the microwave surface resistances of high-T$_c$ YBa$_2$Cu$_3$O$_{7-{\delta}}$(YBCO) films at the frequency of about 19.6 GHz and the temperature of 30 K ${\sim}$ 90 K. An open-ended TE$_{011}$ mode sapphire-loaded cylindrical cavity resonator was used as the measurement probe, where YBCO films were used as the endplates of the cylindrical cavity. The characteristics of the measurement system include functions to display the unloaded ${\varrho}$ and the resonant frequency of the TE$_{011}$ mode resonator as well as the microwave surface resistance of the YBCO films, all simultaneously as a function of temperature. Applicability of the measurement system for investigating the homogeneity in the microwave properties of large high-T$_c$ superconductor films is discussed.

• Progress in Superconductivity
• /
• v.2 no.1
• /
• pp.27-32
• /
• 2000

A prototype for a highly sensitive, automated measurement system for the microwave surface resistance of high-$T_c$ superconductor films was set up, and tested by measuring the microwave surface resistances of high-$T_c$ $YBa_2Cu_3O_{7-\delta}$ (YBCO) films at the frequency of about 19.6 GHz and the temperature of 30 K $\sim$ 90 K. An open-ended $TE_{011}$ mode sapphire-loaded cylindrical cavity resonator was used as the measurement probe, where YBCO films were used as the endplates of the cylindrical cavity. The characteristics of the measurement system include functions to display the unloaded Q and the resonant frequency of the $TE_{011}$ mode resonator as well as the microwave surface resistance of the YBCO films, all simultaneously as a function of temperature. Applicability of the measurement system for investigating the homogeneity in the microwave properties of large high-$T_c$ superconductor films is discussed.