• 제목/요약/키워드: Abrasives

검색결과 192건 처리시간 0.032초

고정 입자 정반을 이용한 사파이어 기판의 연마 특성 연구 (Study on the Lapping Characteristics of Sapphire Wafer by using a Fixed Abrasive Plate)

  • 이태경;이상직;조원석;정해도;김형재
    • Tribology and Lubricants
    • /
    • 제32권2호
    • /
    • pp.44-49
    • /
    • 2016
  • Diamond mechanical polishing (DMP) is a crucial process in a sapphire wafering process to improve flatness and achieve the target thickness by using free abrasives. In a DMP process, material removal rate (MRR) is a key factor to reduce process time and cost. Controlling mechanical parameters, such as velocity and pressure, can increase the MRR in a DMP process. However, there are limitations of using high velocities and pressures for achieving a high MRR owing to their side effects. In this paper, we present the lapping characteristics and improvement of MRR by using a fixed abrasive plate through an experimental study. The change in MRR as a function of velocity and pressure follows Preston's equation. The surface roughness of a wafer decreases as the plate velocity and pressure increases. We observe a sharp decrease in MRR over the lapping time at a high velocity and pressure in the velocity and pressure test. An analysis of surface roughness (Rq and Rpk) indicates that wear of abrasives decreases the MRR sharply. In order to investigate the effect of abrasive wear on the MRR, we utilize a cutting fluid and a rough wafer. The cutting fluid delays the wear of abrasives resulting in improvement of MRR drop. The rough wafer maintains the MRR at a stable rate by self-dressing.

자기연마가공에서 자성입자와 연마재의 크기에 따른 표면개선 효과 (Study on Effect of Particle Size of Ferrous Iron and Polishing Abrasive on Surface Quality Improvement)

  • 이성호;손병훈;곽재섭
    • 대한기계학회논문집A
    • /
    • 제38권9호
    • /
    • pp.1013-1018
    • /
    • 2014
  • 자기연마가공은 연마입자와 자성입자를 혼합한 공구의 유연성을 이용하여, 공작물 표면을 폴리싱하는 특수가공법이다. 기존 연구의 대부분은 가공 정밀도를 향상시키기 위해서 연마입자의 크기를 달리 하는 것에 관한 내용들이다. 그러나 자기연마 가공에서는 연마입자의 크기뿐만 아니라, 자성입자의 크기도 가공에 많은 영향을 미칠 것으로 판단되며 이에 대한 연구가 반드시 필요하다. 따라서 본 연구에서는 크기가 다른 자성입자들을 사용하여 자기연마가공의 효과를 평가하였다. 자성입자는 철분말을 사용하였으며, 직경이 평균 8, 78, $250{\mu}m$의 크기이다. 공작물의 표면거칠기 향상 정도를 비교하여 자성입자의 크기가 자기연마가공의 정밀도에 미치는 효과를 평가하였다. 자성입자의 크기는 표면거칠기의 향상에 많은 영향을 미치며, 직경이 $78{\mu}m$일 때 가장 좋은 표면거칠기의 향상을 나타내었다.

연마제 특성에 따른 차세대 금속배선용 Al CMP (chemical mechanical planarization) 슬러리 평가 (Evaluation of Al CMP Slurry based on Abrasives for Next Generation Metal Line Fabrication)

  • 차남구;강영재;김인권;김규채;박진구
    • 한국재료학회지
    • /
    • 제16권12호
    • /
    • pp.731-738
    • /
    • 2006
  • It is seriously considered using Al CMP (chemical mechanical planarization) process for the next generation 45 nm Al wiring process. Al CMP is known that it has a possibility of reducing process time and steps comparing with conventional RIE (reactive ion etching) method. Also, it is more cost effective than Cu CMP and better electrical conductivity than W via process. In this study, we investigated 4 different kinds of slurries based on abrasives for reducing scratches which contributed to make defects in Al CMP. The abrasives used in this experiment were alumina, fumed silica, alkaline colloidal silica, and acidic colloidal silica. Al CMP process was conducted as functions of abrasive contents, $H_3PO_4$ contents and pressures to find out the optimized parameters and conditions. Al removal rates were slowed over 2 wt% of slurry contents in all types of slurries. The removal rates of alumina and fumed silica slurries were increased by phosphoric acid but acidic colloidal slurry was slightly increased at 2 vol% and soon decreased. The excessive addition of phosphoric acid affected the particle size distributions and increased scratches. Polishing pressure increased not only the removal rate but also the surface scratches. Acidic colloidal silica slurry showed the highest removal rate and the lowest roughness values among the 4 different slurry types.

금속결합제 연삭숫돌의 방전트루잉 성능 평가 (Truing Performance of Metal-Bonded Grinding Wheel by Electro-Discharge Truing Method)

  • 김태규;신건휘;정명원;곽태수
    • 한국기계가공학회지
    • /
    • 제15권3호
    • /
    • pp.79-85
    • /
    • 2016
  • Truing process is a very important process for recovering the shape of wheels worn by continuous grinding operation. In this study, the devices, controller, and spindle for electro-discharge truing were developed, and the electro-discharge truing method was applied to metal-bonded grinding wheels and compared with the conventional truing method. The shapes of the grinding wheels were measured by a surface profile measurement device. The protrusion of abrasives on the surface of the wheels was compared with the conventional truing method using an optic microscope measurement device. The experimental results showed that the performance of the electro-discharge truing method, in terms of the protrusion of abrasives on the surface of the wheels and the recovery of the shape of the worn wheels, was similar to that of the conventional truing method.

자기연마법에 의한 비자성 파이프 내면의 연마특성 (I) (The Internal Finishing Characteristics of Non-ferromagnetic Pipe Polished by Magnetic Abrasive Machining(I))

  • 박원규;노태우;서영일;최환;이종찬;정선환
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2000년도 추계학술대회 논문집
    • /
    • pp.779-782
    • /
    • 2000
  • An internal finishing process by the application of magnetic abrasive machining has been developed as a new technology to obtain a fine inner surface of pipe. In this paper, the finishing process of a non-ferromagnetic pipe by a static magnetic field method is introduced and its finishing characteristics is discussed with effective factors by various experiments. From these experimental results, it is found that the proper suppling quantity of magnetic abrasives per diameter of pipe is important, and the inner surface roughness of pipe is not changed much after certain critical finishing time. As a result of this investigation the 3.2$\mu$m Rmax in inner surface roughness of stainless steel pipe is improved to 0.7$\mu$m Rmax after 6 minutes finishing.

  • PDF

다중회귀분석을 이용한 BK7 글래스 MR Polishing 공정의 재료 제거 조건 분석 (Analysis of Material Removal Rate of Glass in MR Polishing Using Multiple Regression Design)

  • 김동우;이정원;조명우;신영재
    • 한국생산제조학회지
    • /
    • 제19권2호
    • /
    • pp.184-190
    • /
    • 2010
  • Recently, the polishing process using magnetorheological fluids(MR fluids) has been focused as a new ultra-precision polishing technology for micro and optical parts such as aspheric lenses, etc. This method uses MR fluid as a polishing media which contains required micro abrasives. In the MR polishing process, the surface roughness and material removal rate of a workpiece are affected by the process parameters, such as the properties of used nonmagnetic abrasives(particle material, size, aspect ratio and density, etc.), rotating wheel speed, imposed magnetic flux density and feed rate, etc. The objective of this research is to predict MRR according to the polishing conditions based on the multiple regression analysis. Three polishing parameters such as wheel speed, feed rates and current value were optimized. For experimental works, an orthogonal array L27(313) was used based on DOE(Design of Experiments), and ANOVA(Analysis of Variance) was carried out. Finally, it was possible to recognize that the sequence of the factors affecting MRR correspond to feed rate, current and wheel speed, and to determine a combination of optimal polishing conditions.

$BaTiO_3$$TiO_2$ 분말이 혼합된 연마제 슬러리(MAS)를 사용한 BTO 박막의 CMP 특성 (Chemical Mechanical Polishing Characteristics of BTO Films using $TiO_2$- and $BaTiO_3$-Mixed Abrasive Slurry (MAS))

  • 이우선;서용진
    • 대한전기학회논문지:전기물성ㆍ응용부문C
    • /
    • 제55권6호
    • /
    • pp.291-296
    • /
    • 2006
  • In this study, the sputtered BTO film was polished by CMP process with the self-developed $BaTiO_3$- and $TiO_2$-mixed abrasives slurries (MAS), respectively. The removal rate of BTO ($BaTiO_3$) thin film using the $BaTiO_3$-mixed abrasive slurry (BTO-MAS) was higher than that using the $TiO_2$-mixed abrasives slurry ($TiO_2$-MAS) in the same concentrations. The maximum removal rate of BTO thin film was 848 nm/min with an addition of $BaTiO_3$ abrasive at the concentration of 3 wt%. The sufficient within-wafer non-uniformity (WIWNU%) below 5% was obtained in each abrsive at all concentrations. The surface morphology of polished BTO thin film was investigated by atomic force microscopy (AFM).

연마제 혼합액 제트의 절단 성능에 관한 연구 (An experimental study of cutting abilities of an abrasive water jet system)

  • 안영재;유장열;권오관;김영조
    • 대한기계학회논문집
    • /
    • 제13권4호
    • /
    • pp.611-617
    • /
    • 1989
  • 본 연구에서는 제트 분사 시스템을 제작하여 절단 성능에 관게하는 여러 변수중 고압수의 압력, 연마제의 크기 및 공급량, 그리고 공작물의 이송속도의 영향을 실험적으로 연구하였다.

나노 세리아 슬러리를 이용한 STI CMP에서 나노토포그라피 시뮬레이션 (Nanotopography Simulation of Shallow Trench Isolation Chemical Mechanical Polishing Using Nano Ceria Slurry)

  • 김민석;;강현구;박재근;백운규
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
    • /
    • pp.239-242
    • /
    • 2004
  • We investigated the nanotopography impact on the post-chemical mechanical polishing (post-CMP) oxide thickness deviation(OTD) of ceria slurry with a surfactant. Not only the surfactant but also the slurry abrasive size influenced the nanotopography impact. The magnitude of the post-CMP OTD increased with adding the surfactant in the case of smaller abrasives, but it did not increase in the case of larger abrasives, while the magnitudes of the nanotopography heights are all similar. We created a one-dimensional numercal simulation of the nanotopography impact by taking account of the non-Prestonian behavior of the slurry, and good agreement with experiment results was obtained.

  • PDF

Simulation analysis and evaluation of decontamination effect of different abrasive jet process parameters on radioactively contaminated metal

  • Lin Zhong;Jian Deng;Zhe-wen Zuo;Can-yu Huang;Bo Chen;Lin Lei;Ze-yong Lei;Jie-heng Lei;Mu Zhao;Yun-fei Hua
    • Nuclear Engineering and Technology
    • /
    • 제55권11호
    • /
    • pp.3940-3955
    • /
    • 2023
  • A new method of numerical simulating prediction and decontamination effect evaluation for abrasive jet decontamination to radioactively contaminated metal is proposed. Based on the Computational Fluid Dynamics and Discrete Element Model (CFD-DEM) coupled simulation model, the motion patterns and distribution of abrasives can be predicted, and the decontamination effect can be evaluated by image processing and recognition technology. The impact of three key parameters (impact distance, inlet pressure, abrasive mass flow rate) on the decontamination effect is revealed. Moreover, here are experiments of reliability verification to decontamination effect and numerical simulation methods that has been conducted. The results show that: 60Co and other homogeneous solid solution radioactive pollutants can be removed by abrasive jet, and the average removal rate of Co exceeds 80%. It is reliable for the proposed numerical simulation and evaluation method because of the well goodness of fit between predicted value and actual values: The predicted values and actual values of the abrasive distribution diameter are Ф57 and Ф55; the total coverage rate is 26.42% and 23.50%; the average impact velocity is 81.73 m/s and 78.00 m/s. Further analysis shows that the impact distance has a significant impact on the distribution of abrasive particles on the target surface, the coverage rate of the core area increases at first, and then decreases with the increase of the impact distance of the nozzle, which reach a maximum of 14.44% at 300 mm. It is recommended to set the impact distance around 300 mm, because at this time the core area coverage of the abrasive is the largest and the impact velocity is stable at the highest speed of 81.94 m/s. The impact of the nozzle inlet pressure on the decontamination effect mainly affects the impact kinetic energy of the abrasive and has little impact on the distribution. The greater the inlet pressure, the greater the impact kinetic energy, and the stronger the decontamination ability of the abrasive. But in return, the energy consumption is higher, too. For the decontamination of radioactively contaminated metals, it is recommended to set the inlet pressure of the nozzle at around 0.6 MPa. Because most of the Co elements can be removed under this pressure. Increasing the mass and flow of abrasives appropriately can enhance the decontamination effectiveness. The total mass of abrasives per unit decontamination area is suggested to be 50 g because the core area coverage rate of the abrasive is relatively large under this condition; and the nozzle wear extent is acceptable.