運用掃描式探針微影技術研發製作矽質奈米元件結構

Abstract

『奈米科技』已然成為全世界科技發展的重點之一，它亦將引發本世紀在材料、生化、光電、能源等等技術的革命，人類將可從此一先進研發科技中獲得豐碩的實際效益。近年來，奈米科技製程技術的研發受到許多研究團隊的高度重視，其中包含了發展製造奈米級元件結構的先進製作技術，以及設計研究開發新穎的奈米結構以因應未來前瞻性的領域應用。在眾多先進的微影技術當中，例如：電子束微影技術(EBL)，X光微影技術（XRL），以及掃描式探針微影技術(SPL)等技術，其中又以掃描式探針微影技術最具有製造奈米結構元件的潛力，因為此一先進微影技術不僅可應用於奈米尺度下將試片表面的特性轉變改質，並且可應用於製造生產所需的奈米級元件結構。掃描式探針微影技術乃是利用探針接近試片表面的時候，利用外加的電場誘發局部陽極氧化試片(抑或者是利用探針針尖的穿邃電流，來致使試片表面化學官能基分子層結構特性改質)，來製備奈米級元件結構。此種微影技術具有較高的解析度、精確的對準特性、以及可靠度高，也沒有一般微影的輻射熱損害，再加上製作簡易而且有著較低成本等等的優勢。本論文研究也將利用原子力顯微鏡掃描式探針沾附有機分子溶液，並藉由空氣中水分子當媒介，直接在矽質試片上進行奈米級分子層結構圖案的微影塗佈。此種奈米微影方式，探針就如同一隻筆，而有機溶液就如同墨水一般。我們可以藉由此方式來塗佈製造出小於100奈米解析度的各式化學官能基分子層結構圖案。因此，掃描式探針微影技術被視為發展奈米元件的前瞻關鍵技術。在本論文研究，我們在一維的矽質奈米導線上選擇性沈積金奈米粒子，並且將其應用於生物分子及相關的化學物質的感測研究，並將此一前瞻性的技術平台建構完成。矽質奈米導線乃是利用掃描式探針微影技術並結合非等向式四-甲基-氫氧化氨 (TMAH) 濕式蝕刻 (或RIE 乾式蝕刻)來完成的。而15奈米粒徑大小的金奈米粒子乃是利用化學鹽類還原的方式來製備的。然後，我們結合運用掃描式探針微影技術與自我組裝分子層技術在矽質奈米導線的表面進行金奈米粒子的選擇性沈積。我們使用已沾附了2-胺基-乙基-3胺基丙烷三甲氧基矽化合物(AEAPTMS) 有機分子的掃描式探針，並藉由空氣中的水膜分子當作有機分子傳遞擴散的媒介，然後在矽質奈米導線上圖佈沈積有機分子層薄膜，當胺基的有機團修飾在矽質導線表面上時，便會使得矽質導線表面產生帶正離子的矽烷化改質效應。此外，本論文研究也成功地利用掃描式探針微影技術在二氧化矽表面利用AFM探針針尖的穿邃電流來致使試片表面 2-胺基乙基-3胺基丙烷三甲氧基矽化合物(AEAPTMS)化學官能基有機分子層鍵結產生斷鍵而使試片表面改質。然後，藉由庫倫力的吸引作用，而與帶負電的金奈米粒子產生靜電吸附而沈積鍵結在矽質奈米導線上的矽烷化改質結構區域。我們深信此一前瞻性奈米製造技術藉由結合掃描式探針微影技術與自我組裝分子層技術所研發製造出的奈米結構元件，未來將可廣泛地應用於奈米電子元件與奈米生醫感測元件的研究領域，無論在學術及工業技術研究上皆極具價值。更重要的一點，本研究對於未來奈米級的電子元件製程技術的研發上，提供了一套操作容易且成本低廉的奈米元件製程研發技術。

One of the focal points that “nanotechnology” has already become development in science and technology of whole world. It will also cause the revolution in the technology, such as material, biochemistry, photo electricity, energy, etc. in this century. Mankind can obtain the actual benefit from this advanced nanotechnology. Recently, it is more interesting in research on nanotechnology, which includes the development of advanced manufacturing skills for fabricating nanometer size devices and the design and research of new nanometer structures for novel applications. Among these advanced lithography techniques, such as electron beam lithography, x-ray lithography and scanning probe lithography (SPL), etc., one potential approach for fabricating the nanostructures is the use of scanning probe lithography. SPL techniques have been used to perform nano-scaled surface modification, and dominated the research field of nano-structures fabrication. SPL, employing a conductive probe to induce electric-field-enhanced local anodic oxidation (or tunneling currents enhanced the surface modification of chemical functionality), provide its advantages of high resolution, alignment accuracy, high reliability, absence of radiation damage, simpler and lower-cost. We also utilize the AFM scanning tip as a “pen” to transport an “ink” containing organic molecules onto a substrate surface via a water meniscus to write nano structures and subsequently read patterns, it is possible to create nano-scale patterns with remarkable resolution (<100 nm) and simultaneously control the chemical functionality of the written regions. This makes SPL a unique tool that has been considered as a crucial technology for nanometer scale structures. In this research, we propose a novel platform based on one-dimensional silicon nano-wires (SiNWs) and gold nano-particles for detection of the biological molecular and chemical species. SiNWs were performed based on SPL technique and anisotropic tetra-methyl-ammonium hydroxide (TMAH) wet etching (or RIE dry etching). Gold nano-particles were obtained by chemical reduction methods, and the diameter size of gold nano-particles was controlled by the reaction time. Then, we will utilize a combination of scanning probe nanolithography and self-assembly monolayer (SAMs) techniques for realizing selective deposition of gold nanoparticles onto the SiNWs surface. AFM scanning tip was adopted to deposit organic N-(2-aminoethyl)-3-amino-propyl-tri-methoxysilane (AEAPTMS) molecules nanopatterns through a water meniscus onto the SiNWs surface. In addition, selective patterning of self-assembled AEAPTMS monolayer on the thin SiO2 surface of SiNWs is realized by using SPL local filed-induced bond breaking technique. Afterwards, amino silane molecules modification as linkers for selectively anchoring gold nano-particles onto silanation modification patterns on the SiNWs surface via Coulomb force. It is believed that the proposed nanofabrication technique combined SPL method with the SAMs process can be further applied in both nano-electronics and nano-biochemical sensors applications.