• 제목/요약/키워드: Surface uniformity

검색결과 674건 처리시간 0.034초

A Study on the Deposit Uniformity and Profile of Cu Electroplated in Miniaturized, Laboratory-Scale Through Mask Plating Cell for Printed Circuit Board (PCBs) Fabrication

  • Cho, Sung Ki;Kim, Jae Jeong
    • Korean Chemical Engineering Research
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    • 제54권1호
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    • pp.108-113
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    • 2016
  • A miniaturized lab-scale Cu plating cell for the metallization of electronic devices was fabricated and its deposit uniformity and profile were investigated. The plating cell was composed of a polypropylene bath, an electrolyte ejection nozzle which is connected to a circulation pump. In deposit uniformity evaluation, thicker deposit was found on the bottom and sides of substrate, indicating the spatial variation of deposit thickness was governed by the tertiary current distribution which is related to $Cu^{2+}$ transport. The surface morphology of Cu deposit inside photo-resist pattern was controlled by organic additives in the electrolyte as it led to the flatter top surface compared to convex surface which was observed in the deposit grown without organic additives.

산화제 첨가에 따른 WO3 박막의 CMP 평탄화 특성 (Planarization Characteristics of CMP for WO3 Film with an Addition of Oxidizers)

  • 이우선;고필주;김남훈;서용진
    • 한국전기전자재료학회논문지
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    • 제18권1호
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    • pp.12-16
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    • 2005
  • Chemical mechanical polishing (CMP) process is one of the most useful methods for improving the surface roughness of films. The effects of CMP on the surface morphology of WO$_3$ films prepared by RF sputtering system were investigated in this paper. A removal rate of films increased, and the uniformity performance of surface decreased with the addition of an oxidizer to the tungsten slurry. Non-uniformity performance of surface was superior as its value was below 5 % when oxidizers of 5.0 vol% and 2.5 vol%, respectively, were added to the tungsten slurry. The optimized oxidizer concentration, reflected both the improved roughness values and hillock-free surface with the good uniformity performance, was 5.0 vol% as an atomic force microscopy(AFM) analysis of thin film topographies. Our CMP results will be a useful reference for advanced technology of thin films for gas sensor applications in the near future.

연마불균일도에 영향을 미치는 패드 표면특성에 관한 연구 (The Effect of Pad Surface Characteristics on Within Wafer Non-uniformity in CMP)

  • 박기현;박범영;정재우;이현섭;정석훈;정해도;김형재
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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    • pp.38-39
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    • 2005
  • We have investigated the effect of the pad surface characteristics such as roughness, groove density and wear of pad on within wafer non-uniformity(WIWNU) in chemical mechanical polishing(CMP). We found that WIWNU increases as pad surface roughness($R_{pk}$; Reduced peak height) increases in an early stage of polishing. But after polishing time goes to a certain extent, WIWNU decreases as uniformity of pad surface roughness. Also, groove of pad has effect on relative pad stiffness although original mechanical properties of pad are unchanged by grooving. WIWNU decreases as relative pad stiffness decreases. In addition, conditioning process causes non-uniform wear of pad during in CMP. The profile of pad wear has a significant effect on WIWNU.

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Fabrication of a Staircase Coil with Improved SNR and Image Uniformity by Structural Changes of a Conventional Birdcage Coil at 1.5T MRI

  • Ryang, Kyung-Seung;Shin, Yong-Jin
    • 한국자기공명학회논문지
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    • 제7권1호
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    • pp.25-36
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    • 2003
  • The performance of radio frequency (RF) coils, used in MRI units, is determined by the image uniformity and the signal-to-noise ratio (SNR). Birdcage and surface coils are commonly used. A birdcage coil provides a good image uniformity while a surface coil produces a high SNR. In this study, therefore, a staircase coil was designed from a standard version of a birdcage coil, with some structural changes to increase SNR while maintaining image uniformity. In phantom experiments, the improvement of the image to uniformity and the SNR increase of the staircase coil compared with the values for the birdcage coil were about 3.5% and 35%, respectively. In clinical experiment, the SNR increase of the staircase coil, compared with the value for the birdcage coil was about 40% in bone, muscle and blood-vessel tissues. These results show that the performance of the staircase coil was very improved over the standard birdcage coil in terms of SNR, and that image uniformity was maintained. Therefore, the staircase coil designed by this study should be useful in experimental and clinical l.5T MRI systems, and this coil offers an alternative method of quadrature detection.

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엣지형 LED 백라이트의 조도 균일도 향상을 위한 도광판 설계에 관한 연구 (Study on the Simulation Model of Edge-lit Backlight for Improving Illuminance Uniformity)

  • 박지희;이정호;남기봉;고재현;김중현
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2009년도 추계학술대회 논문집
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    • pp.73-76
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    • 2009
  • The optical structure of edge-lit LED backlight has been optimized via simulation study in order to remove bright spots appearing on the entrance region of the light guide plate (LGP) and thus to improve the luminance uniformity. The density of scattering dots located on the back surface of LGP was adjusted according to the location of LED's. In addition, lenticular lenses or a diffuse transmissive surface were formed on the side surface of LGP facing the LED's, and the density of lenticular lenses was optimized for redistributing rays emitted from LED's into wider angles. The bright spots which could be seen from conventional LED backlight were removed by the combination of these two optical structures. The application of diffuse surface to the entrance face gave better uniformity than the application of lenticular lenses. However, dark regions still appear on the entrance region of LGP, which should be removed by more appropriate optical design for achieving better luminance uniformity on the LED backlight.

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백색 LED 증착용 MOCVD 장치에서 유도가열을 이용한 기판의 온도 균일도 향상에 관한 연구 (Study of Temperature Uniformity Improvement of Inductive Heating in MOCVD Systems to Deposit White LED)

  • 홍광기;양원균;주정훈;이승호;이태완
    • 한국표면공학회지
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    • 제43권6호
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    • pp.304-308
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    • 2010
  • Deposition temperature uniformity of GaN based MQW (multiple quantum well) layers is an important key which affects the wavelength uniformity of white LEDs. Temperature uniformity was assessed by infrared images for both cases of a static and a rotating susceptor. Rotating the susceptor at 2.5 rpm over the induction heater gave 4.3% of temperature non-uniformity. Temperature distribution of the graphite susceptor over the induction heater was numerically modelled and agreed with experimental results.

CdTe 후막을 이용한 직접변환방식 X-선 검출기 물성평가 (Investigation of CdTe thick films for direct conversion type X-ray detector)

  • 김민제;송풍근
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2015년도 춘계학술대회 논문집
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    • pp.113-113
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    • 2015
  • 본 연구에서는 thermal evaporation법을 이용하여 제작한 CdTe 후막의 미세구조, 전기적 특성 및 X-선 조사에 따른 특성을 비교분석하였다. 기판온도를 $370{\sim}450^{\circ}C$로 변화시키며 증착하였으며, CdCl2 첨가에 따른 미세구조 변화를 관찰하였다. CdTe 막의 상 하부에 전극을 형성하여 I-V 특성을 평가하고, 실제 X-ray를 샘플에 조사하여 sensitivity를 측정하였다. 박막형성 초기에는 기판온도가 증가함에 따라 grain size가 증가하였지만, grain uniformity는 감소하였다. X-ray 특성향상을 위해서는 grain size와 uniformity 모두 중요한 인자이기 때문에 uniformity 향상을 위해 Cl을 첨가하였다. 미량의 Cl 첨가에서는 큰 변화를 보이지 않았지만 더 많은 양의 Cl 첨가 시, grain size 와 uniformity 모두 증가되는 것을 확인하였으며, 그에 따라 I-V, X-ray 조사 특성 모두 개선되는 것을 확인할 수 있었다.

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NEW EVALUATION METHODS FOR RADIAL UNIFORMITY IN NEUTRON TRANSMUTATION DOPING

  • Kim, Hak-Sung;Lim, Jae-Yong;Pyeon, Cheol-Ho;Misawa, Tsuyoshi;Shiroya, Seiji;Park, Sang-Jun;Kim, Myong-Seop;Oh, Soo-Youl;Jun, Byung-Jin
    • Nuclear Engineering and Technology
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    • 제42권4호
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    • pp.442-449
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    • 2010
  • Recently, the neutron irradiation for large diameter silicon (Si)-ingots of more than 8" diameter is requested to satisfy the demand for the neutron transmutation doping silicon (NTD-Si). By increasing the Si-ingot diameter, the radial non-uniformity becomes larger due to the neutron attenuation effect, which results in a limit of the feasible diameter of the Si-ingot. The current evaluation method has a certain limit to precisely evaluate the radial uniformity of Si-ingot because the current evaluation method does not consider the effect of the Si-ingot diameter on the radial uniformity. The objective of this study is to propose a new evaluation method of radial uniformity by improving the conventional evaluation approach. To precisely predict the radial uniformity of a Si-ingot with large diameter, numerical verification is conducted through comparison with the measured data and introducing the new evaluation method. A new concept of a gradient is introduced as an alternative approach of radial uniformity evaluation instead of the radial resistivity gradient (RRG) interpretation. Using the new concept of gradient, the normalized reaction rate gradient (NRG) and the surface normalized reaction rate gradient (SNRG) are described. By introducing NRG, the radial uniformity can be evaluated with one certain standard regardless of the ingot diameter and irradiation condition. Furthermore, by introducing SNRG, the uniformity on the Si-ingot surface, which is ignored by RRG and NRG, can be evaluated successfully. Finally, the radial uniformity flattening methods are installed by the stainless steel thermal neutron filter and additional Si-pipe to reduce SNRG.

평판형 히트파이프식 핫척의 표면온도 균일화 향상을 위한 연구 (Study on Improvement of Surface Temperature Uniformily in Flate-Plate Heat Pipe Hot Chuck)

  • 김대현;이석호;임택규;이충구
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2369-2374
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    • 2008
  • In the precision hot plate for wafer processing, the temperature uniformity of upper plate surface is one of the key factors affecting the quality of wafers. Precision hot plates require temperature variations less than ${\pm}1.5%$ during heating to $120^{\circ}C$. In this study, we have manufactured the flat plate heat pipe hot chuck of circle type(300mm) and investigated the operating characteristics of flat plate heat pipe hot chuck experimentally. Various liquids(aceton, FC-40, water) were used as the working fluid and charging ratio was changed($14{\sim}36\;vol.%$). Several cases were tested to improve temperature uniformity. Major working fluid to be investigated was water. Using water, various parameters such as charging ratio, wafer operation on-off time, different working fluids. In case of water, the temperature uniformity was ${\pm}1.5%$, response time of wafer were investigated.

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고압 중수소 어닐링을 통한 SiO2 절연체의 균일성 개선 (Enhancement of SiO2 Uniformity by High-Pressure Deuterium Annealing)

  • 김용식;정대한;박효준;연주원;길태현;박준영
    • 한국전기전자재료학회논문지
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    • 제37권2호
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    • pp.148-153
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    • 2024
  • As complementary metal-oxide semiconductor (CMOS) is scaled down to achieve higher chip density, thin-film layers have been deposited iteratively. The poor film uniformity resulting from deposition or chemical mechanical planarization (CMP) significantly affects chip yield. Therefore, the development of novel fabrication processes to enhance film uniformity is required. In this context, high-pressure deuterium annealing (HPDA) is proposed to reduce the surface roughness resulting from the CMP. The HPDA is carried out in a diluted deuterium atmosphere to achieve cost-effectiveness while maintaining high pressure. To confirm the effectiveness of HPDA, time-of-flight secondary-ion mass spectrometry (ToF-SIMS) and atomic force microscopy (AFM) are employed. It is confirmed that the absorbed deuterium gas facilitates the diffusion of silicon atoms, thereby reducing surface roughness.