• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.7 no.2
• /
• pp.59-65
• /
• 1982

In this paper, the CdS single crystal, which was grown as piper-polish method, was Ion-bombarded with Sb and In, and the thermally stimulated current of the spot that was Ionbombarded was measured. In the sample which was individually bombarded by Sb and In, the over-lapping peak was found, this over lapping peak was separated, by the method of thermal cleaning, showing the trap levels of 0.25(eV) and 0.31(eV) at the temperature of 147(K) and 181(K). While the spot is being cooled down and excited with photolight at the same time, the trap level 0.25(eV) disappeared and the new trap level of 0.85(eV) appeared. It can be said that the better photo-conductive crystals, the T.S.C is better measured.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.05a
• /
• pp.128-133
• /
• 1999

In recent years, LSI devices have become more powerful and lower-priced, caused by a development of various wafer materials and an increase in the diameter of wafers. On the other hand, these have created some serious problems in manufacturing of wafers because materials used as semiconductor substrate are very brittle. In view of this fact, there are some trials to apply shear-mode(or ductile-mode) grinding for efficient manufacturing of semiconductor wafers instead of conventional lapping process. In fact grinding process that has not only more excellent degree of accuracy but also more adaptable to fully automated manufacturing than lapping, is already used in Si machining field. This paper described the elementary studies to establish the grinding technology of wafers. First, we investigated the variation of grinding force and the transition of grinding mode as various grinding conditions. Then, it was inspected that the change of grinding force affected the integrity such as the topography and the roughness of ground surfaces, and led to the chemical defects generation and distribution in damaged layer. The degree of defects was estimated by FT-IR(Fourier Transformed Infrared) Spectroscopy and Auger Electron Spectroscopy

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2004.05b
• /
• pp.623-626
• /
• 2004

The purpose of this paper is to determinate and to confirm p-n junction depth with nondestructive method by using electron beam. By measuring the critical short circuit current on the p-n junction which induced by electron beam and calculating generation range, the diffusion depth can be obtained. It ran be seen that values destructively measured by constant angle lapping and nondestructively by this study almost concur. As this result, it is purposed that diffusion depth of p-n junction can be easily measured by non-destruction. And this nondestructive method ran be recommended highly to the industrial analysis.

• Tribology and Lubricants
• /
• v.34 no.6
• /
• pp.209-216
• /
• 2018

Sapphire is a substrate material that is widely used in optical and electronic devices. However, the processing of sapphire into a substrate takes a long time owing to its high hardness and chemical inertness. In order to process the sapphire ingot into a substrate, ingot growth, multiwire sawing, lapping, and polishing are required. The lap grinding process using pellets is known as one of the ways to improve the efficiency of sapphire substrate processing. The lap grinding process ensures high processing efficiency while utilizing two-body abrasion, unlike the lapping process which utilizes three-body abrasion by particles. However, the lap grinding process has a high material removal rate (MRR), while its weakness is in obtaining the required surface roughness for the final polishing process. In this study, we examine the effects of free abrasives in lap grinding on the material removal characteristics of sapphire substrate. Before conducting the lap grinding experiments, it was confirmed that the addition of free abrasives changed the friction force through the pin-on-disk wear test. The MRR and roughness reduction rate are experimentally studied to verify the effects of free abrasive concentration on deionized water. The addition of free abrasives (colloidal silica) in the lap grinding process can improve surface roughness by three-body abrasion along with two-body abrasion by diamond grits.

• Journal of Astronomy and Space Sciences
• /
• v.21 no.2
• /
• pp.141-152
• /
• 2004

Optics fabrication process for precision space optical parts includes bound abrasive grinding, loose abrasive lapping and polishing. The traditional bound abrasive grinding with bronze bond cupped diamond wheel leaves the machine marks of about $20{mu}m$ rms in height and the subsurface damage of about 1 ${mu}m$ rms in height to be removed by subsequent loose abrasive lapping. We explored an efficient quantitative control of precision CNC grinding. The machining parameters such as grain size, work-piece rotation speed and feed rate were altered while grinding the work-piece surfaces of 20-100 mm in diameter. The input grinding variables and the resulting surface quality data were used to build grinding prediction models using empirical and multi-variable regression analysis. The effectiveness of such grinding prediction models was then examined by running a series of precision CNC grinding operation with a set of controlled input variables and predicted output surface quality indicators. The experiment achieved the predictability down to ${pm}20$ nm in height and the surface roughness down to 36 nm in height. This study contributed to improvement of the process efficiency reaching directly the polishing and figuring process without the need for the loose abrasive lapping stage.

• Proceedings of the IEEK Conference
• /
• 2000.06b
• /
• pp.68-71
• /
• 2000

In this paper, we have measured the oxygen contents by FTIR in silicon wafer various process technology(slicing, lapping, polishing). The measured data are also compared with the data of etching process(KOH, Bright etching). Also we have measured the surface morpology in backside silicon wafer after etching treatment and etch pit density due to OISF after 4 step high temperature annealing process with optical microscope.

• 한국가스학회:학술대회논문집
• /
• 2003.10a
• /
• pp.197-202
• /
• 2003

• Journal of information and communication convergence engineering
• /
• v.5 no.4
• /
• pp.324-327
• /
• 2007

In this paper, the p-n junction depth with nondestructive method by using scanning electron microscopy (SEM) is determined and conformed. By measuring the critical short circuit current on the p-n junction which induced by electron beam and calculating generation range, the diffusion depth can be obtained. It can be seen that values destructively measured by constant angle lapping and nondestructively by this study almost concur. As this result, it is purposed that diffusion depth of p-n junction can be easily measured by nondestruction. This nondestructive method can be recommended highly to the industrial analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1992.04a
• /
• pp.18-22
• /
• 1992

This paper presents the process of manufacturing technology of ceramics ferrule for optical fiber connector. Precision zirconia ceramic ferrules is widely used for high performance and low cost single mode optical fiber connectors. To polish the hole of the zirconia ceramic ferrule, the wire lapping instrument is developed and the machining experiment is conducted. Through the centerless grinding using diamond wheel the surface roughness of zirconia ceramics ferrule is below the 1 .mu. m Rmax.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.190-193
• /
• 1990

Die finishing (polishing and lapping) after NC machining is characterized as one bottleneck process for reducing lead time. For automation of this typical manual work, a flexible polishing tool system using industrial robot has been developed. This tool system has three principal functions in order to achieve reduction of waviness, 3 D.O.F. compliance and constant pressure structure. This polishing tool shows that adaptability to free form surface is increased and programmability to various areas of die surface is also acquired.