Nano-imprinting Lithography Technology І

Nano-imprinting Lithography Technology І

Agenda Limitation of photolithograph - Remind of photolithography technology - What is diffraction - Diffraction limit Concept of nano-imprinting lithography Basic process of nano-imprinting lithography technology

Remind of photolithography technology Photoresist process for lithography Clean substrate Development Apply Adhesion Promoter(HMDS) PR Spin Coating Post Baking Soft Baking Etching Limitation of photolithography UV Exposure Remove PR

Photolithography process and limitation UV Exposure Mask Ideal case of photolithography UV Exposure Real case of photolithography (ultra small pattern size) 회절로인해같은조건의촬영시위와같은상이한결과를초래 Diffraction effect (Image blur 현상발생 )

What is diffraction? Diffraction is the process by which light waves traveling through a small hole, slit or around a boundary will spread out Basic assumption : Light is wave

What is diffraction? Diffraction causes the loss of resolving power Image blur 현상은각종수차에의해영향을받지만공기중의 particle 에의한 diffraction 으로인해같은조건의촬영시위와같은상이한결과를초래한다

Diffraction limit Example Diffraction of circular aperture is a Bessel function of the first kind

Diffraction limit The radius of the Airy disk D θ

Nano-imprinting Lithography Technology II

Imprinting 현존하는가장오래된금속활자본직지심체요절 < 금속활자본 > < 목판본 > < 금속활자본표지 > 정식명칭 : 백운화상초록불조직지심체요절 1377년 ( 고려우왕 3) 7월청주흥덕사간행 세계에서가장오래된금속활자본 1372년쓰여진책을 77년금속, 78년목판으로간행 금속활자본은현재프랑스국립도서관에소장 2001년유네스코세계기록유산등재 자료출처 : http://www.jikjiworld.net

Imprinting 직지심체요절금속활자제작및인쇄과정 < 글자본선정 > < 자본붙이기 > < 어미자만들기 > < 주형틀만들기 > < 쇳물붓기 > < 활자떼어내기 > < 조판 > < 인쇄 > 자료출처 : http://www.jikjiworld.net

Nano-imprinting process 1. Mold fabricaion step - Using E-beam lithography, FIB, etc. 1. Mold fabrication Mold 2. Press mold Mold < Mold > 2. Imprinting step - Nano mold with nano-scale pattern is pressed into a resist 3. Remove mold Resist Substrate Mold Resist Substrate < Resist pattern >

Nano-imprinting 기술의종류

Basic process of nano-imprinting lithography technology Procedure of nanoimprinting lithography : 2 basic step 1. Imprint step - Nano mold with nano-scale pattern is pressed into a resist 2. Pattern transfer step - Pattern transfer to substrate by RIE (Reactive Ion Etching) - RIE is used to remove the residual resist in the compressed area 1. Pressing mold 2. Remove mold mold resist resist substrate mold resist resist substrate < Mold > 3. Pattern transfer (RIE) resist substrate < Resist pattern > 자료출처 : Proc. SPIE 4349, (2001), p. 82

Thermal nano-imprinting lithography technology Procedures Heating of Substrate and Mold to above Tg 1. Press mold with heat Application of Molding Pressure Cooling of Substrate and Mold to below Tg 2. Remove mold Mold Resist Substrate Mold < Mold > Demolding Resist Substrate 자료출처 : http://www.obducat.com/default.aspx?id=187 < Imprinted resist >

UV nano-imprinting lithography technology UV nano-imprinting Material: UV-curable photopolymer Processing condition: room temp. & low pressure No fluidity problem Procedures <Lattice pattern> <Pyramid pattern> Substrate Photopolymer UV-transparent mold Photopolymer dispensation on substrate Covering the mold Aligning UV-light Releasing the mold Pressure 자료출처 : http://www.obducat.com/default.aspx?id=187 JJAP, vol. 44, No. 7B, pp. 5600, 2005

Continuous UV nano-imprinting lithography technology Design and construction of continuous UV nano imprinting system Continuous UV nano-imprinting system For flexible substrate For rigid substrate Fabrication results 1. Can replicate nano patterns of large area with high precision 2. Can replace conventional lithography process

Imprinting system

EVG 社 EVG 620 bond aligner Precise wafer/substrate alignment for wafer bonding applications High-resolution bottom side splitfield microscope 1 µm alignment accuracy Easy to use Windows based operation

.. SUSS 社 NPS 300 (Nano patterning stepper) 250 nm overlay accuracy Unmatched sub-20 nm embossing capability Submicron Stamp-to-Wafer alignment with state-of-the-art pattern recognition system

Molecular Imprint 社 Imprio 250 Resolution: Sub-50 nm Alignment: < 10 nm Flexibility: 200 mm and 300mm substrates with automated loading Field size: 26 x 32 mm active print area.

Nano & Device 社 Nanosis 610 No align option Near zero residual layer UV curing & hot embossing (universal) Good pattern uniformity 6 inch direct imprinting

Issues of nanoimprinting Fabrication of nano master / mold Thickness of residual layer Large area patterning Demolding Imprinting material Mass productivity and system itself

Nano Imprinting Lithography Technology III

Agenda Thickness of residual layer Mass productivity and system itself - Large area patterning - Mass productivity

Thickness of residual layer

What is residual layer? UV-transparent mold Imprinting material (photopolymer) Pressure UV- curing This is the residual layer! After the residual layer etching

Importance of thickness of residual layer Purpose of the nano imprinting lithography Use the pattern itself - AR Surface - Optical nano grating - Wave guider - Nano structure for optoelectronic devices Use the pattern as a barrier for after process - Replace the photolithography process

AR coating on mold AR coating (Anti reflection coating) UV Reflection of UV Mold without AR coating PHotopolymer Optical substrate has about 4% reflection in general AR coating on mold surface is very important

Importance of thickness of residual layer Nano structure for optoelectronic devices (MLA on VCSEL) n 1 R n 1 R Emitting area n 1 R VCSEL array Bonding pad VCSEL Micro-Lens Fiber We must control the residual layer for designed focal length

Importance of thickness of residual layer Use the pattern as a barrier for after process (critical reason) UV-transparent mold UV photopolymer Preparation Mold lamination and Appling pressure UV curing Demolding Remove the residual layer Etch the substrate Remove the photopolymer 이때 pattern 의크기에비해너무두꺼운 residual layer 가남아있다면 이를제거할때 pattern 은모두손실되고만다

Zero residual layer process Conventional imprint Zero residual imprint

Application of nano-imprinting technology I

Super hydrophobic surface 연꽃잎 자료출처 : http://blog.empas.com/hl1vgt/, Manhui Sun, Langmuir, Vol.21, pp.8978, 2005 L. Feng, Advanced Material,Vol.14, pp.1857, 2002 Alexander Otten, Langmuir, Vol.20, pp.2405, 2004

Super hydrophobic surface 연꽃잎의모사 응용분야 매미날개의모사 < 자동차 > 자료출처 : Manhui Sun et at al.,langmuir, vol.21, pp.8978, 2005 Woo Lee et at al., Langmuir, Vol.20, pp.7665, 2004 http://www.dumitrup.com/blog/ < 유리창 >

Anti-reflective surface 나방의눈 자료출처 : http://www.motheye.com/, http://blog.empas.com/squirrel1226/1

Anti-reflective surface 나방눈의모사패턴 무반사면의응용 자료출처 : http://www.motheye.com/, http://www.nature.go.kr/insect/insectguide/ MNE 06 Micro- and Nano- Engineering Kenji Sogo, Journal of Photopolymer Science Technology, Vol.19, pp.647, 2006

Drag reduction of surface 상어의피부 자료출처 : http://news.softpedia.com/news/the-shark-coating-42520.shtml D. W. Bechert, Naturwissenschaften, Vol. 87, pp.157, 2004

Drag reduction of surface 상어피부 상어피부형상의응용 - 수영복 10% 감소효과 <Drag reduction of surface> 자료출처 : http://www.speedo.com D. W. Bechert, Naturwissenschaften, Vol. 87, pp.157, 2004 <Speedo Fastskin II>

Application of nano-imprinting technology II

Bio chip fabrication using nano-imprinting Imprinting of bio chip 자료출처 : http://bmc.ub.uni-potsdam.de, http://www. macrogen.co.kr

Bio chip fabrication using nano-imprinting

Lab-on-a-chip fabrication using nano-imprinting LOC with microfluidic channels 자료출처 : http://www.biodent.com, http://pubs.rsc.org