• Title/Summary/Keyword: anisotropic etching

Search Result 172, Processing Time 0.026 seconds

The Optimum Condition of Anisotropic Bulk(10) Si Etching with KOH for High Selectivity and Low Surface Roughness

  • Lim, Hyung-Teak;Kim, Yong-Kweon;Lee, Seung-Ki
    • Journal of Electrical Engineering and information Science
    • /
    • v.2 no.5
    • /
    • pp.108-113
    • /
    • 1997
  • In this paper, the optimum condition of (110) Si etching with the potassium hydroxide(KOH) etchant is presented. Although several researches on (110) Si anisotropic etching have been studied, there has been lack of effects of mask quality and etching conditions on the selectivity and the roughness o the etched surface. Three kinds of masks (film, emulsion and E-beam mask) were used in order to verify the effect of etching properties. Anisotropic bulk etching depends on the crystalline orientation and the concentration and temperature of the etchant. In order to investigate the effect of etching conditions on selectivity and the roughness of the etched surface, the concentration of the etchant was varied from 35 to 45 per cent in weight with increments by 5 per cent and the temperature was changed from 70 to 90$^{\circ}C$ with increments by 10$^{\circ}C$. The combination of the temperature of 70$^{\circ}C$ and the concentration of 40wt.% was found to be the optimum etching condition for high selectivity. Etched surfaces show minimum surfaces show minimum surface roughness at a temperature of 80$^{\circ}C$ and a concentation of 40wt.%. Comb structures with various comb widths were fabricated and the lengths of the combs wree measured with several etching time durations. A micro comb structure 525$\mu\textrm{m}$ high was fabricated for MEMS application.

  • PDF

TMAH/IPA Anisotropic Etching Characteristics with Addition of Pyrazine (Pyrazine이 첨가된 TMAH/IPA 이방성 식각특성)

  • 박진성;정귀상
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1997.04a
    • /
    • pp.23-26
    • /
    • 1997
  • This work presents the TMAH/IPA anisotropic etching characteristics with addition of Pyrazine. (100) Si etching rate of 0.747 ${\mu}{\textrm}{m}$/min at 8$0^{\circ}C$ was obtained using TMAH 25 wt.% / IPA 17 vol.% / pyrazine 0.1 g. The etching rate of (100) Si is increased about 52% compare to pure TMAH 25 wt.%. But etching rate of (100) Si is decreased with increasing Pyrazine additive. Activation energy of TMAH/IPA/pyrazine is much lower than TMAH and TMAH/IPA solutions. Addition of Pyrazine does not effect on surface flatness and decreases undercutting ratio about 20 %. Therefore, TMAH/IPA/pyrazine is an attractive anisotropic etchant because of alkaline-ion free.

  • PDF

Anisotropic Wet Etching of Single Crystal Silicon for Formation of Membrane Structure (멤브레인 구조 제작은 위한 단결정 실리콘의 이방성 습식 식각)

  • 조남인;강창민
    • Journal of the Semiconductor & Display Technology
    • /
    • v.2 no.4
    • /
    • pp.37-40
    • /
    • 2003
  • We have studied micro-machining technologies to fabricate parts and sensors used in the semiconductor equipment. The studies were based on the silicon integrated circuit processes, and composed of the anisotropic etching of single crystal silicon to fabricate a membrane structure for hot and cold junctions in the infrared absorber. KOH and TMAH were used as etching solutions for the anisotropic wet etching for membrane structure formation. The etching characteristic was observed for the each solution, and etching rate was measured depending upon the temperature and concentration of the etching solution. The different characteristics were observed according to pattern directions and etchant concentration. The pattern was made to incline $45^{\circ}$ on the primary flat, and optimum etching property was obtained in the case of 30 wt% and $90^{\circ}C$ of KOH etching solution for the formation of the membrane structure.

  • PDF

The study of Ag etching effect by adding compound on the lead frame process (Lead frame 공정 중 화합물에 따른 Ag 에칭효과)

  • 이경수;박수길
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2001.07a
    • /
    • pp.859-862
    • /
    • 2001
  • This study describes a selective Ag etching solution for use with pattern on the surface of copper. This etching solution uses potassium iodide and potassium sulfate as the ligand that coordinates to the metal ions and ferricyanide as the oxidant. The etching rate was depended on the concentration of co-ligands and time. But the etching rate wasn't depended on the pH(2∼6), and oxidant(K$_3$Fe(CN)$\_$6/). Complete etching of silver can be achieved rapidly within 90sec for 4.46${\mu}$m thick metal films when aqueous solutions containing K$_3$Fe(CN)$\_$6/, K$_2$S$_2$O$\_$8/ and KI was used. This etching solution was characteristic of anisotropic etching.

  • PDF

A Study on Anisotropic Etching Characteristics of Silicon in TMAH/AP Solutions and Fabrication of a Diaphragm (TMAH/AP 용액의 실리콘 이방성 식각특성 및 다이아프램 제작에 대한 연구)

  • 윤의중;김좌연;이태범;이석태
    • Proceedings of the IEEK Conference
    • /
    • 2003.07b
    • /
    • pp.1033-1036
    • /
    • 2003
  • In this paper, Si anisotropic etching characteristics of tetramethylammonium hydroxide (TMAH)/ ammonium persulfate (AP) solutions were investigated to realize the optimum structure of a diaphragm for the piezoresistive pressure sensor application. Due to its low toxicity and its high compatibility with the CMOS processing, TMAH was used as Si anisotropic etchants. The variations of Si etch rate on the etching temperature, TMAH concentration, and etching time were obtained. With increasing the etching temperature and decreasing TMAH concentrations, the Si etch rate is increased while a significant non-uniformity exists on the etched surface because of formation of hillocks on the <100> surface. With the addition of AP to TMAH solution, the Si etch rate is increased and an improvement in flatness on the etching front is observed. The Si etch rate is also maximized with increasing the number of addition of AP to TMAH solution per one hour. The Si square diaphragms of 20${\mu}{\textrm}{m}$ thickness and 100~400${\mu}{\textrm}{m}$ one-side length were fabricated successfully by applying optimum Si etching conditions of TMAH/AP solutions.

  • PDF

The Etching Characteristics of TMAH/AP for the Diaphragm Fabrication of Pressure Sensors (압력센서용 다이아프램 제작을 위한 TMAH/AP 식각특성)

  • 윤의중;김좌연
    • Journal of the Semiconductor & Display Technology
    • /
    • v.2 no.4
    • /
    • pp.19-22
    • /
    • 2003
  • In this paper, Si anisotropic etching characteristics of tetramethylammonium hydroxide (TMAH)/ammonium persulfate (AP) solutions were investigated to realize the optimum structure of a diaphragm for the piezoresistive pressure sensor application. Due to its low toxicity and its high compatibility with the CMOS processing, TMAH was used as Si anisotropic etchants. The variations of Si etch rate on the etching temperature, TMAH concentration, and etching time were obtained. With increasing the etching temperature and decreasing TMAH concentrations, the Si etch rate is increased while a significant non-uniformity exists on the etched surface because of formation of hillocks on the <100> surface. With the addition of AP to TMAH solution, the Si etch rate is increased and an improvement in flatness on the etching front is observed. The Si etch rate is also maximized with increasing the number of addition of AP to TMAH solution per one hour. The Si square diaphragms of 20$\mu\textrm{m}$ thickness and 100-400 $\mu\textrm{m}$ one-side length were fabricated successfully by adding AP of (5/6)g to 800 ml TMAH solution every 10 minutes.

  • PDF

Multi-mode Planar Waveguide Fabricated by a (110) Silicon Hard Master

  • Jung, Yu-Min;Kim, Yeong-Cheol
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.18 no.12
    • /
    • pp.1106-1110
    • /
    • 2005
  • We fabricated (110) silicon hard master by using anisotropic wet etching for embossing. The etching chemical for the silicon wafer was a TMAH $25\%$ solution. The anisotropic wet etching produces a smooth sidewall surface and the surface roughness of the fabricated master is about 3 nm. After spin coating an organic-inorganic sol-gel hybrid material on a silicon substrate, we employed hot embossing technique operated at a low pressure and temperature to form patterns on the silicon substrate by using the fabricated master. We successfully fabricated the multi-mode planar optical waveguides showing low propagation loss of 0.4 dB/cm. The surface roughness of embossed patterns was uniform for more than 10 times of the embossing processes with a single hydrophobic surface treatment of the silicon hard master.

Fabrication of Knife type Si tip array by orientation dependent etching of single silicon substrate (단결정 Si 기판의 결정 의존성 식각에 의한 Knife형 Si tip array의 제조)

  • Jung, Yu-Ho;Ko, Chang-Gi;Kim, Chul-Ju;Ju, Byeong-Kwon;Oh, Myung-Hwan
    • Proceedings of the KIEE Conference
    • /
    • 1995.07c
    • /
    • pp.1428-1430
    • /
    • 1995
  • In this study we fabricate Knife type Si-tip array using (110) Si wafer. We can fabricate vertical structure by anisotropic etching using EPW and observe it by SEM. After the step, we perform isotropic etching and oxidation sharpening of the structure and also observe it by SEM, respectively. The purpose of isotropic etching is to reduce the oxidation time. We attain a optimal tip whose radius is about $100{\AA}$ after anisotropic etching 2.25 min.+isotropic etching 5 min.+oxidation 1 hour and 23 min.

  • PDF

Selective Etching of Silicon in TMAH:IPA:Pyrazine Solutions (TMAH:IPA:Pyrazine 용액에서 실리콘의 선택식각)

  • Chung, Gwiy-Sang;Lee, Chae-Bong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2000.04b
    • /
    • pp.112-116
    • /
    • 2000
  • This paper presents anisotropic ethcing characteristics of single-crystal silicon in tetramethylammonium hydroxide(TMAH):isopropyl alcohol(IPA) solutions containing pyrazine. With the addition of IPA to TMAH solutions, etching characteristics are exhibited that indicate an improvement in flatness on the etching front and a reduction in undercutting, but the etch rate on (100) silicon is decreased. The (100) silicon etch rate is improved by the addition of pyrazine. An etch rate on (100) silicon of $0.8\;{\mu}m/min$, which is faster by 13 % than a 20 wt.% solution of pure TMAH, is obtained using 20 wt.% TMAH:0.5 g/100 ml pyrazine solutions, but the etch rate on (100) silicon is decreased if more pyrazine is added. With the addition of pyrazine to a 25 wt.% TMAH solution, variations in flatness on the etching front were not observed and the undercutting ratio was reduced by 30 ~ 50 %.

  • PDF

A Study on Manufacturing of LCD Prism Sheets Through Silicon Anisotropic Etching (실리콘 이방성 식각을 통한 LCD 프리즘 시트 제작 연구)

  • Jeon, Kwangseok;Ryoo, Kunkul
    • Korean Journal of Metals and Materials
    • /
    • v.46 no.6
    • /
    • pp.377-381
    • /
    • 2008
  • Prism sheet of LCD BLU which depends on supply from Japan and U.S.A was studied by using Si anisotropic etching and injection molding technologies. First, the prism sheet was patterned on Si wafer through photolithography, and the best conditions of Si etching were determined through etching Si wafer with TMAH to obtain straight optimized zigzag patterns, and a cross pattern to provide light diffusion and concurrent focusing. The etch rate of TMAH was concluded to be constant for $25wt%-70^{\circ}C$ condition. Ni stamp of prism sheet was made by electrodeposition using patterned Si wafer, normal or fast H/C(Heating/Cooling) injections were carried out to fabricate prism sheet. It was known that fast H/C injection could fabricate prism sheet more accurately than normal injection. Zigzag patterns and the cross pattern showed higher transmissivity than the straight patterns because of light diffusion through diagonal direction. The fast H/C injection for zigzag patterns showed lower transmissivity than normal injection because there occurred more light diffusion through precise injection patterns, but the fast H/C injection for straight patterns showed only refraction without diffusion, causing lower transmissivity than normal injection.