Determination of precise crystallographic directions for mask alignment in wet bulk micromachining for MEMS
Tóm tắt
In wet bulk micromachining, the etching characteristics are orientation dependent. As a result, prolonged etching of mask openings of any geometric shape on both Si{100} and Si{110} wafers results in a structure defined by the slowest etching planes. In order to fabricate microstructures with high dimensional accuracy, it is vital to align the mask edges along the crystal directions comprising of these slowest etching planes. Thus, precise alignment of mask edges is important in micro/nano fabrication. As a result, the determination of accurate crystal directions is of utmost importance and is in fact the first step to ensure dimensionally accurate microstructures for improved performance. In this review article, we have presented a comprehensive analysis of different techniques to precisely determine the crystallographic directions. We have covered various techniques proposed in the span of more than two decades to determine the crystallographic directions on both Si{100} and Si{110} wafers. Apart from a detailed discussion of each technique along with their design and implementation, we have provided a critical analysis of the associated constraints, benefits and shortcomings. We have also summed up the critical aspects of each technique and presented in a tabular format for easy reference for readers. This review article comprises of an exhaustive discussion and is a handy reference for researchers who are new in the field of wet anisotropic etching or who want to get abreast with the techniques of determination of crystal directions.
Tài liệu tham khảo
Ashok A, Pal P (2015) Silicon micromachining in 25 wt% TMAH without and with surfactant concentrations ranging from ppb to ppm. Microsyst Technol 1–8. doi:10.1007/s00542-015-2699-9
Lee S, Park S, Cho D (1999) The surface/bulk micromachining (SBM) process: a new method for fabricating released microelectromechanical systems in single crystal silicon. J Microelectromech Syst 8:409–416
Frühauf J (2005) Shape and functional elements of the bulk silicon microtechnique: a manual of wet-etched silicon structures. Springer, Berlin
Pal P, Chandra S (2004) Bulk-micromachined structures inside anisotropically etched cavities. Smart Mater Struct 13:1424–1429
Tellier CR, Charbonnieras AR (2003) Characterization of the anisotropic chemical attack of (hhl) silicon plates in a TMAH 25 wt% solution: micromachining and adequacy of the dissolution slowness surface. Sens Actuators A Phys 105:62–75
Schnakenberg U, Benecke W, Lochel B (1990) NH4OH-based etchant for silicon micromachining. Sens Actuators A Phys 23:1031–1035
Zubel I, Kramkowska M (2009) Possibilities of extension of 3D shapes by bulk micromachining of different Si (hkl) substrates. J Micromech Microeng 15:485–493
Pal P, Sato K (2015) A comprehensive review on convex and concave corners in silicon bulk micromachining based on anisotropic wet chemical etching. Micro Nano Syst Lett 3:1–42
Gad-el-Hak M (ed) (2002) The MEMS handbook. CRC Press LLC, Boca Raton
Elwenspoek M, Jansen H (1998) Silicon micromachining. Cambridge University Press, UK
Takahata K (2013) Advances in micro/nano electromechanical systems and fabrication technologies. InTech, Rijeka
Lindroos V, Tilli M, Lehto A, Motooka T (2010) Handbook of silicon based MEMS materials and technologies. William Andrew Publishing, Norwich
Hsu TR (2003) MEMS & microsystems: design and manufacture. Tata McGraw-Hill Publishing Company Ltd, New Delhi
Madou MJ (2002) Fundamentals of microfabrication: the science of miniaturization, 2nd edn. CRC Press, Boca Raton
Varadan VK, Vinoy KJ, Gopalakrishnan S (2006) Smart material systems and MEMS: design and development methodologies. Wiley, New York
Lang W (1996) Silicon microstructuring technology. Mater Sci Eng R Rep 17:1–55
Bustillo JM, Howe RT, Muller RS (1998) Surface micromachining for microelectromechanical systems. IEEE Proc 86:1552–1574
Bhatt V, Pal P, Chandra S (2005) Feasibility study of RF sputtered ZnO film for surface micromachining. Surf Coat Technol 198:304–308
Kovacs GT, Maluf NI, Petersen KE (1998) Bulk micromachining of silicon. IEEE Proc 86:1536–1551
Petersen KE (1982) Silicon as a mechanical material. IEEE Proc 70:420–457
Jansen H, Gardeniers H, Boer MD, Elwenspoek M, Fluitman J (1996) A survey on the reactive ion etching of silicon in microtechnology. J Micromech Microeng 6:14–28
Oehrlein GS (1990) Reactive ion etching. In: Rossnagel SM, Westwood WD, Haber JJ (eds) Handbook of plasma processing technology-fundamentals, etching, deposition, and surface interactions. Noyes, Park Ridge
Coburn JW, Winters HF (1979) Plasma etching-a discussion of mechanisms. J Vaccum Sci Technol 16:391–403
Larmer F, Schilp P (1994) Method of anisotropically etching silicon. German Patent DE 4(241):045
Jiang E, Keating A, Martyniuk M, Prasad K, Faraone L, Jiang JM (2012) Characterization of low-temperature bulk micromachining of silicon using an SF6/O2 inductively coupled plasma. J Micromech Microeng 22:095005
Hynes AM, Ashraf H, Bhardwaj JK, Hopkins J, Johnston I, Shepherd JN (1999) Recent advances in silicon etching for MEMS using the ASE process. Sens Actuators A Phys 74:13–17
Teng J, Prewett PD (2005) Focused ion beam fabrication of thermally actuated bimorph cantilevers. Sens Actuators A Phys 123–124:608–613
Walker CK, Narayanan G, Knoepfle H, Capara J, Glenn J, Hungerford A, Bloomstein TM, Palmacci ST, Stern MB, Curtin JE (1997) Laser micromachining of silicon: a new technique for fabricating high quality terahertz waveguide components. In: Proceedings of 8th international symposium on space terahertz technology, Harvard University, p 358
Schwartz B, Robbins H (1976) Chemical etching of silicon. J Electrochem Soc 123(12):1903–1909
Zandi K, Arzi E, Izadi N, Mohajerzadeh S, Haji S, Abdi Y, Asl Soleimani E (2006) Study of bulk micromachining for ⟨100⟩ silicon. Eur Phys J Appl Phys 35:7–12
Lee DB (1969) Anisotropic etching of silicon. J Appl Phys 40:4569–4575
Bean KE (1978) Anisotropic etching of silicon. IEEE Trans Electron Devices 25:1185–1193
Seidel H, Csepregi L, Heuberger A, Baumgartel H (1990) Anisotropic etching of crystalline silicon in alkaline solutions I: orientation dependence and behavior of passivation layers. J Electrochem Soc 137(11):3612–3626
Sato K, Shikida M, Matsushima Y, Yamashiro T, Asaumi K, Iriye Y, Yamamoto M (1998) Characterization of orientation-dependent etching properties of single-crystal silicon: effects of KOH concentration. Sens Actuators A Phys 61:87–93
Dutta S, Imran Md, Kumar P, Pal R, Datta P, Chatterjee R (2011) Comparison of etch characteristics of KOH, TMAH and EDP for bulk micromachining of silicon (110). Microsyst Technol 17:1621–1628
Powell O, Harrison HB (2001) Anisotropic etching of 100 and 110 planes in (100) silicon. J Micromech Microeng 11:217–220
Tanaka H, Yamashita S, Abe Y, Shikida M, Sato K (2004) Fast etching of silicon with a smooth surface in high temperature ranges near the boiling point of KOH solution. Sens Actuators A Phys 114:516–520
Matsuoka M, Yoshida Y, Moronuki M (1992) Preparation of silicon thin diaphragms free from micropyramids using anisotropic etching in KOH solution. J Chem Eng 25:735–740
Baryeka I, Zubel I (1995) Silicon anisotropic etching in KOH-isopropanol etchant. Sens Actuators A Phys 48:229–238
Shikida M, Sato K, Tokoro K, Uchikawa D (2000) Differences in anisotropic etching properties of KOH and TMAH solutions. Sens Actuators A Phys 80:179–188
Backlund Y, Rosengren L (1992) New shapes in (100) Si using KOH and EDP etches. J Micromech Microeng 27:5–9
Pal P, Ashok A, Haldar S, Xing Y, Sato K (2015) Anisotropic etching in low concentration KOH: effects of surfactant concentration. Micro Nano Lett 10(4):224–228
Tanaka H, Cheng D, Shikida M, Sato K (2006) Characterization of anisotropic wet etching properties of single crystal silicon: effects of ppb-level of Cu and Pb in KOH solution. Sens Actuators A Phys 128:125–131
Tabata O, Asahi R, Funabashi H, Shimaoka K, Sugiyama S (1992) Anisotropic etching of silicon in TMAH solutions. Sens Actuators A Phys 34(1):51–57
Tang B, Shikida M, Sato K, Pal P, Amakawa H, Hida H, Fukuzawa K (2010) Study of surfactant-added TMAH for the applications in DRIE + wet etching based micromachining. J Micromech Microeng 20:065008
Mukhiya R, Bagolini A, Margesin B, Zen M, Kal S (2006) <100 > bar corner compensation for CMOS compatible anisotropic TMAH etching. J Micromech Microeng 16:2458–2462
Sato K, Shikida M, Yamashiro T, Asaumi K, Iriye Y, Yamamoto M (1999) Anisotropic etching rates of single-crystal silicon for TMAH water solution as a function of crystallographic orientation. Sens Actuators A Phys 73:131–137
Pal P, Sato K, Gosalvez MA, Tang B, Hida H, Shikida M (2010) Fabrication of novel microstructures based on orientation dependent adsorption of surfactant molecules in TMAH solution. J Micromech Microeng 21(1):015008
Pal P, Sato K (2010) Fabrication methods based on wet etching process for the realization of silicon MEMS structures with new shapes. Microsyst Technol 16(7):1165–1174
Gosalvez MA, Tang B, Pal P, Sato K, Kimura Y, Ishibashi K (2009) Orientation and concentration dependent surfactant adsorption on silicon in aqueous alkaline solutions: explaining the changes in the etch rate, roughness and undercutting for MEMS applications. J Micromech Microeng 19(12):125011
Steinsland E, Finstad T, Hanneborg A (2000) Etch rates of (100), (111), and (110) single-crystal silicon in TMAH measured in situ by laser reflectance interferometry. Sens Actuators A Phys 86:73–80
Tang B, Yao MQ, Tan G, Pal P, Sato K, Su W (2014) Smoothness control of wet etched Si{100} surfaces in TMAH + Triton. Key Eng Mater 609:536–541
Shikida M, Masuda T, Uchikawa D, Sato K (2001) Surface roughness of single-crystal silicon etched by TMAH solution. Sens Actuators A Phys 90(3):223–231
Tang B, Sato K, Zhang D, Cheng Y (2014) Fast Si (100) etching with a smooth surface near the boiling temperature in surfactant modified tetramethylammonium hydroxide solutions. Micro Nano Lett 9(9):582–584
Gosalvez MA, Pal P, Ferrando N, Hida H, Sato K (2011) Experimental procurement of the complete 3D etch rate distribution of Si in anisotropic etchants based on vertically micromachined wagon wheel samples. J Micromech Microeng 21:125007
Tang B, Pal P, Gosalvez MA, Shikida M, Sato K, Amakawa H, Itoh S (2009) Ellipsometry study of the adsorbed surfactant thickness on Si{110} and Si{100} and the effect of pre-adsorbed surfactant layer on etching characteristics in TMAH. Sens Actuators A Phys 156:334–341
Chung GS (2005) Anisotropic etching characteristics of Si in tetramethylammonium hydroxide: isopropyl alcohol: pyrazine solutions. J Korean Phys Soc 46(5):1152–1156
Choi WK, Thong JTL, Luo P, Tan CM, Chua TH, Bai Y (1998) Characterisation of pyramid formation arising from the TMAH etching of silicon. Sens Actuators A Phys 71:238–243
Resnik D, Vrtacnik D, Aljancic U, Amon S (2003) Effective roughness reduction of 100 and 311 planes in anisotropic etching of 100 silicon in 5 % TMAH. J Micromech Microeng 13:26–34
Sakaino K, Adachi S (2001) Study of Si(100) surfaces etched in TMAH solution. Sens Actuators A Phys 88:71–78
Pal P, Sato K, Gosalvez MA (2012) Etched profile control in anisotropic etching of silicon by TMAH + Triton. J Micromech Microeng 22(6):065013
Resnik D, Vrtacnik D, Aljancic U, Amon S (2000) Wet etching of silicon structures bounded by (311) sidewalls. Microelectron Eng 51:555–566
Holke A, Henderson HT (1999) Ultra-deep anisotropic etching of (110) silicon. J Micromech Microeng 9:51–57
Thong JTL, Choi WK, Chong CW (1997) TMAH etching of silicon and the interaction of etching parameters. Sens Actuators A Phys 63(3):243–249
Seidel H, Csepregi L, Heuberger A, Baumgartel H (1990) Anisotropic etching of crystalline silicon in alkaline solutions II: influence of dopants. J Electrochem Soc 137:3626–3632
Wu MP, Wu QH, Ko WH (1986) A study on deep etching of silicon using ethylenediamine-pyrocatechol-water. Sens Actuators A Phys 9:333–343
Reisman A, Berkenblit M, Chan SA, Kaufmann FB, Green DC (1979) The controlled etching of silicon in catalyzed ethylene-diamine-pyrochatechol-water solutions. J Electrochem Soc Solid-State Sci Technol 126:1406–1415
Kern W (1978) Chemical etching of silicon, germanium, gallium arsenide, and gallium phosphide. RCA Rev 39:278–307
Declercq MJ, Gerzberg L, Meindl JD (1975) Optimization of the hidrazine-water solution for anisotropic etching of silicon in integrated circuit technology. J Electrochem Soc Solid State Sci 122:545–552
Schnakenberg U, Benecke W, Lochel B (1990) NH4OH-based etchant for silicon micromachining. Sens Actuators A Phys 23:1031–1035
Clarck LD, Lund JL, Edell DJ (1988) Cesium hydroxide (CsOH): a useful etchant for micromachining silicon. In: Tech. digest, IEEE solid state sensor and actuator workshop (Hilton Head Island, SC), pp 5–8
Pal P, Singh SS (2013) A simple and robust model to explain convex corner undercutting in wet bulk micromachining. Micro Nano Syst Lett 1(1):1–6
Pal P, Singh SS (2013) A new model for the etching characteristics of corners formed by Si{111} planes on Si{110} wafer surface. Engineering 5(11):1–8
Kandlikar SG, Grande WJ (2003) Evolution of microchannel flow passages-thermohydrolic performance and fabrication technology. Heat Transf Eng 24:3–17
Koo JM, Jian L, Zhang L, Kenny T, Santiago J, Goodson K (2001) Modeling of two-phase microchannel heatsinks for VLSI chips In: 14th IEEE international conference on micro electro mechanical systems, MEMS, IEEE, Interlaken, pp 422–426
James TD, Parish G, Winchester KJ, Musca CA (2006) A crystallographic alignment method in silicon for deep, long microchannel fabrication. J Micromech Microeng 16(10):2177
Pal P, Sato K (2009) Various shapes of silicon freestanding microfluidic channels and microstructures in one step lithography. J Micromech Microeng 19(5):055003
Abedinov N, Grabiec P, Gotszalk T, Tz Ivanov, Voigt J, Rangelow IW (2001) Micromachined piezoresistive cantilever array with integrated resistive microheater for calorimetry and mass detection. J Vaccum Sci Technol A 19:2884–2888
Saya D, Belaubre P, Mathieu F, Lagrange D, Pourciel JB, Bergaud C (2005) Si-piezoresistive microcantilevers for highly integrated parallel force detection applications. Sensors Actuators A Phys 123:23–29
Lee JH, Hwang KS, Park J, Yoon KH, Yoon DS, Kim TS (2005) Immunoassay of prostate-specific antigen (PSA) using resonant frequency shift of piezoelectric nanomechanical microcantilever. Biosens Bioelectron 20:2157–2162
Battiston FM, Ramseyer JP, Lang HP, Baller MK, Gerber C, Gimzewski JK, Meyer E, Guntherodt HJ (2001) A chemical sensor based on a microfabricated cantilever array with simultaneous resonance frequency and bending readout. Sens Actuators B Chem 77:122–131
Wee KW, Kang GY, Park J, Kang JY, Yoon DS, Parkb JH, Kim TS (2005) Novel electrical detection of label-free disease marker proteins using piezoresistive self-sensing micro-cantilevers. Biosens Bioelectron 20:1932–1938
Pruitt BL, Kenny TW (2003) Piezoresistive cantileveres and measurement systems for characterizing low force electrical contacts. Sens Actuators A Phys 104:68–77
Baller MK, Lang HP, Fritz J, Gerber C, Gimzewski JK, Drechsler U, Rothuizen H, Despont M, Vettiger P, Battiston FM, Ramseyer JP (2000) A cantilever array-based artificial nose. Ultramicroscopy 82(1):1–9
Pal P, Sato K (2009) Suspended Si microstructures over controlled depth micromachined cavities for MEMS based sensing devices. Sens Lett 7:11–16
Zhang Y, Tadigadapa S (2004) Calorimetric biosensors with integrated microfluidic channels. Biosens Bioelectron 19:1733–1743
Winter W, Hohne GWH (2003) Chip-calorimeter for small samples. Thermochim Acta 403:43–53
Van Herwaarden AW, Van Duyn DC, Van Oudheusden BW, Sarro PM (1989) Integrated thermopile sensors. Sens Actuators A Phys 22:621–630
Sarro PM, van Hexwaarden AW, van der Vlist W (1994) A silicon-silicon nitride membrane fabrication process for smart thermal sensors. Sens Actuators A Phys 42(1):666–671
Wang CC, Gogoi BP, Monk DJ, Mastrangelo CH (2000) Contamination-insensitive differential capacitive pressure sensors. IEEE J Microelectromech Syst 9:538–543
Tiren J, Tenerz L, Hok B (1989) A batch-fabricated non-reverse valve with cantilever beam manufactured by micromachining of silicon. Sens Actuators 18:389–396
Oh KW, Ahn CH (2006) A review of microvalves. J Micromech Microeng 16(5):R13–R39
Bien DCS, Mitchell SJN, Gamble HS (2003) Fabrication and characterization of a micromachined passive valve. J Micromech Microeng 13:557–562
Au AK, Lai H, Utela BR, Folch A (2011) Microvalves and Micropumps for BioMEMS. Micromachines 2:179–220
Tsai NC, Sue CY (2007) Review of MEMS-based drug delivery and dosing systems. Sens Actuators A Phys 134:555–564
Nisar A, Afzulpurkar N, Mahaisavariya B, Tuantranont A (2008) MEMS-based micropumps in drug delivery and biomedical applications. Sens Actuators B Chem 130:917–942
Laser DJ, Santiago JG (2004) A review of micropumps. J Micromech Microeng 14:35–64
Woias P (2005) Micropumps-past, progress and future prospects. Sens Actuators B Chem 105:28–38
Sharma J, Krishanapura N, Das GA (2012) Fabrication of low pull-in voltage RF MEMS switches on glass substrate in recessed CPW configuration for V-band application. J Micromech Microeng 22:025001
Pal P, Sato K, Chandra S (2007) Fabrication techniques of convex corners in (100)-silicon wafer using bulk micromachining: a review. J Micromech Microeng 17:R11–R13
Gravesen P, Branebjerg J, Jensen OS (1993) Microfluidics—a review. J Mioromech Microeng 3:168–182
Vangbo M, Backlund Y (1996) Precise mask alignment to the crystallographic orientation of silicon wafers using wet anisotropic etching. J Micromech Microeng 6(2):279
Tseng FG, Chang KC (2002) Precise [100] crystal orientation determination on ⟨110⟩-oriented silicon wafers. J Micromech Microeng 13(1):47
Ensell G (1996) Alignment of mask patterns to crystal orientation. Sens Actuators A Phys 3(1):345–348
Lai JM, Chieng WH, Huang YC (1998) Precision alignment of mask etching with respect to crystal orientation. J Micromech Microeng 8(4):327
Ciarlo DR (1992) A latching accelerometer fabricated by the anisotropic etching of (110) oriented silicon wafers. J Micromech Microeng 2(1):10
Chang WH, Huang YC (2005) A new pre-etching pattern to determine ⟨110⟩ crystallographic orientation on both (100) and (110) silicon wafers. Microsyst Technol 11(2–3):117–128
Chen PH, Hsieh CM, Peng HY, Chyu MK (2000) Precise mask alignment design to crystal orientation of (100) silicon wafer using wet anisotropic etching. In: Micromachining and microfabrication international society for optics and photonics, pp 462–466
Singh SS, Veerla S, Sharma V, Pandey AK, Pal P (2016) Precise identification of ⟨100⟩ directions on Si 001 wafer using a novel self-aligning pre-etched technique. J Micromech Microeng 26(2):025012
Singh SS, Avvuru NV, Veerla S, Pandey AK, Pal P (2016) A measurement free pre-etched pattern to identify the ⟨110⟩ directions on Si{110} wafer. Microsys Technol pp 1–7. doi:10.1007/s00542-016-2984-2
Pal P, Gosalvez MA, Sato K (2010) Silicon micromachining based on surfactant-added tetramethyl ammonium hydroxide: etching mechanism and advanced application. Japan J Appl Phys 49:056702
Gosalvez MA, Pal P, Tang B, Sato K (2010) Atomistic mechanism for the macroscopic effects induced by small additions of surfactants to alkaline etching solutions. Sens Actuator A Phys 157(1):91–95
Sekimura M (1999) Anisotropic etching of surfactant-added TMAH solution. In: Proceedings 12th IEEE micro-electro-mechanical systems conference, Orlando, pp 650–655
Pal P, Sato K, Gosalvez MA, Shikida M (2007) Study of rounded concave and sharp edge convex corners undercutting in CMOS compatible anisotropic etchants. J Micromech Microeng 17:2299–2307
Resnik D, Vrtacnik D, Aljancic U, Mozek M, Amon S (2005) The role of Triton surfactant in anisotropic etching of 110 reflective planes on (100) silicon. J Micromech Microeng 15:1174–1183
Yang CR, Yang CH, Chen PY (2005) Study on anisotropic silicon etching characteristics in various surfactant-added tetramethylammonium hydroxide water solutions. J Micromech Microeng 15:202837
Sarro PM, Brida D, Vlist W, Brida S (2000) Effect of surfactant on surface quality of silicon microstructures etched in saturated TMAHW solutions. Sens Actuator A Phys 85:340–345
Pal P, Sato K, Gosalvez MA, Kimura Y, Ishibashi K, Niwano M, Hida H, Tang B, Itoh S (2009) Surfactant adsorption on single crystal silicon surfaces in TMAH solution: orientation-dependent adsorption detected by in situ infra-red spectroscopy. J Microelectromech Syst 18:1345–1356
Pal P, Sato K, Shikida M, Gosalvez MA (2009) Study of corner compensating structures and fabrication of various shapes of MEMS structures in pure and surfactant added TMAH. Sens Actuators A Phys 154:192203
Xu YW, Michael A, Kwok CY (2011) Formation of ultra-smooth 45˚ micromirror on (100) silicon with low concentration TMAH and surfactant: techniques for enlarging the truly 45˚ portion. Sens Actuators A Phys 166:16471
Rola KP, Ptasiski K, Zakrzewski A, Zubel I (2014) Silicon 45 micromirrors fabricated by etching in alkaline solutions with organic additives. Microsys Technol 20:221–226
Yagyu H, Yamaji T, Nishimura M, Sato K (2010) Forty-five degree micromirror fabrication using silicon anisotropic etching with surfactant-added tetramethylammonium hydroxide solution. Japan J Appl Phys 49:096503
Pal P, Haldar S, Singh SS, Ashok A, Xing Y, Sato K (2014) A detailed investigation and explanation to the appearance of different undercut profiles in KOH and TMAH. J Micromech Microeng 24:095026
Gosalvez MA, Li Y, Ferrando N, Pal P, Sato K, Xing Y (2016) Fluctuations during anisotropic etching: local recalibration and application to Si{110}. J Microelectromech Syst 25:1–11