1、PAS 135:2007Terminology for nanofabricationICS 01.040.71; 71.100.99NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWPUBLICLY AVAILABLE SPECIFICATIONPublishing and copyright informationThe BSI copyright notice displayed in this document indicates when the document was last issued
2、. BSI 2007ISBN 978 0 580 61320 3Publication historyFirst published December 2007Amendments issued since publicationAmd. no. Date Text affectedPAS 135:2007 BSI 2007 iPAS 135:2007ContentsForeword iiiIntroduction 11 Scope 12 Classifiers (general terms) 23 Bottom up 34 Top down 45 Abbreviations 14Annexe
3、sAnnex A (informative) Etching machines 15Bibliography 17Summary of pagesThis document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 17 and a back cover.PAS 135:2007ii BSI 2007 This page deliberately left blank BSI 2007 iiiPAS 135:2007ForewordPublishing informationThis Pu
4、blicly Available Specification (PAS) has been commissioned by the UK Department for Innovation, Universities and Skills (DIUS) and developed through the British Standards Institution. It came into effect on 31 December 2007.Acknowledgement is given to the following organizations that were involved i
5、n the development of this terminology:Cavendish Lab, Cambridge; CENAMPS; National Physical Laborator; Psi-tran Ltd; University of Glasgow; University of Southampton.In addition, acknowledgement is given to the contributions of those that commented, including BSI Technical Committee NTI/1, Nanotechno
6、logies, the working groups of ISO Technical Committee ISO/TC 229, Nanotechnologies, and other organizations and experts.BSI retains ownership and copyright of this PAS. BSI reserves the right to withdraw or amend this PAS on receipt of authoritative advice that it is appropriate to do so. This PAS w
7、ill be reviewed at intervals not exceeding two years, and any amendments arising from the review will be published as an amended PAS and publicized in Update Standards.This PAS is not to be regarded as a British Standard. It will be withdrawn upon publication of its content in, or as, a British Stan
8、dard.The PAS process enables a specification to be rapidly developed in order to fulfil an immediate need in industry. A PAS may be considered for further development as a British Standard, or constitute part of the UK input into the development of a European or International Standard.Relationship w
9、ith other publicationsThis PAS is issued as part of a suite of nanotechnology terminology PASs: PAS 71, Vocabulary Nanoparticles; PAS 131, Terminology for medical, health and personal care applications of nanotechnologies; PAS 132, Terminology for the bio-nano interface; PAS 133, Terminology for nan
10、oscale measurement and instrumentation; PAS 134, Terminology for carbon nanostructures; PAS 135, Terminology for nanofabrication; PAS 136, Terminology for nanomaterials.PAS 135:2007iv BSI 2007PAS 131 to PAS 136 include terms the definitions for which differ to those given in PAS 71:2005, which was p
11、ublished in June 2005. These differences are the result of further reflection and debate and reflect consensus within the PAS steering groups. Until PAS 71:2005 can be revised to incorporate these changes, it is intended that the terms in PAS 131 to PAS 136 take precedence over PAS 71:2005.This suit
12、e of PAS acknowledges the standards development work being conducted by BSI Technical Committee NTI/1, Nanotechnologies, ISO TC/229, Nanotechnologies, IEC/TC 113, Nanotechnology standardization for electrical and electronic products and systems, and CEN/TC 352, Nanotechnologies. Attempts have been m
13、ade to align the definitions in these PASs with the definitions being developed by these committees, particularly the draft ISO/TS 27687 Terminology and definitions for nanoparticles. However, as the work of these committees is at a development stage, complete alignment has not been possible in ever
14、y instance.Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a Publicly Available Specification cannot confer immunity from legal obligations. BSI 2007 1PAS 13
15、5:2007Introduction Many authorities predict that applications of nanotechnologies will ultimately pervade virtually every aspect of life and will enable dramatic advances to be realized in most areas of communication, health, manufacturing, materials and knowledge-based technologies. Even if this is
16、 only partially true, there is an obvious need to provide industry and research with suitable tools to assist the development, application and communication of the technologies. One essential tool in this armoury will be the harmonization of the terminology and definitions used in order to promote t
17、heir common understanding and consistent usage. This terminology includes terms that are either specific to the sector covered by the title or are used with a specific meaning in the field of nanotechnology. It is one of a series of terminology PASs covering many different aspects of nanotechnologie
18、s. This terminology attempts not to include terms that are used in a manner consistent with a definition given in the Oxford English Dictionary 1, and terms that already have well established meanings and to which the addition of the prefix “nano” changes only the scale to which they apply but does
19、not otherwise change their meaning.The multidisciplinary nature of nanotechnologies can lead to confusion as to the precise meaning of some terms because of differences in usage between disciplines. Users are advised that, in order to support the standardization of terminology, this PAS provides sin
20、gle definitions wherever possible.1 ScopeThis Publicly Available Specification (PAS) lists terms and definitions used in or associated with the naming or describing of applications of nanotechnologies to the fabrication of components, devices, structures or systems with nanoscale dimensions, known t
21、hroughout this document as nanofabrication. The terms relate specifically to the production of structures and device elements that are typically less than 100 nm in more than 1-dimension.It is applicable to, though is not limited to, fabrication tools and techniques for electrical, electronic, magne
22、tic, mechanical, optical components, devices, structures and systems, and for the fabrication of larger structures, components, devices and systems from nanoscale elements. NOTE The term nanolithography is used by some as a synonym for nanofabrication. In this document, nanolithography is regarded a
23、s one part of the process of nanofabrication.This PAS is intended for use by technologists, regulators, non-government organizations (NGOs), consumer organizations, members of the public and others with an interest in the application or use of nanotechnologies in the subject area. NOTE The fabricati
24、on of nanoparticles is covered in PAS 71:2005.PAS 135:20072 BSI 20072 Classifiers (general terms) 2.1 nanoscalesize range from approximately 1 nm to 100 nmNOTE 1 Properties that are not extrapolations from larger size will typically, but not exclusively, be exhibited in this size range.NOTE 2 The lo
25、wer limit in this definition (approximately 1 nm) has no physical significance but is introduced to avoid single and small groups of atoms from being designated as nano-objects or elements of nanostructures, which might be implied by the absence of a lower limit. ISO/TS 276871)2.2 nanostructurenanos
26、cale structure2.3 nanolithographyprocess of defining an arbitrary pattern with minimum feature sizes of less than 100 nm2.4 self-assemblyassembling of components to create a new level of organization without external input2.5 directed assemblyformation of a nanostructure that can, in principle, have
27、 any defined pattern2.6 top down and bottom upprocess that progresses from larger units to smaller units progressing from small or subordinate units to a larger and functionally richer unitderived from The American Heritage Dictionary of the English Language 22.7 resista radiation sensitive material
28、 NOTE 1 Exposure to patterned radiation produces a latent image in the resist, so after development a relief pattern is left in the resist on the substrate.NOTE 2 With a positive resist the exposed material is removed by the developer, with a negative resist the unexposed material is removed by the
29、action of the developer.2.8 additive processinglayer of new material is added, in order to leave a pattern of deposited material on the substrate NOTE Two terms are used to describe additive processing using resist: lift-off and stencil. In lift-off the layer of new material is applied to the whole
30、surface, the pattern is revealed after the removal of the unexposed resist with the overlaid material; with a stencil the new material is only added where the surface is not protected by resist (as with electro-plating with a resist layer in place). 1)In preparation. BSI 2007 3PAS 135:20072.9 subtra
31、ctive processingmaterial is removed except where the surface is protected by the patterned resist2.10 printingprocess in which a whole pattern is transferred in one process step2.11 direct writing primary lithographyprocess in which the pattern is written into the resist in a serial fashion NOTE Thi
32、s process can be used directly or can define a pattern that can be printed.2.12 maskphysical embodiment of a pattern NOTE A dark/light field photo-mask has the pattern defined in, respectively, transparent/opaque openings in an opaque/transparent background. By extension, a masking layer in resist o
33、n underlying layers of material written by primary lithography is often described as a mask. 2.13 templatephysical embodiment of a pattern in relief that allows replication of the pattern (albeit inverted) that can be used to transfer the patternNOTE The word template encompasses moulds, dies and st
34、amps.2.14 natural lithography fabrication process in which the definition of the primary pattern is by the replication of a naturally occurring pattern NOTE For example, the stripes that occur on collagen fibres or the pattern formed by strands of RNA. The term refers to the use of a mask or templat
35、e that does not require the use of a focused beam of radiation to define the pattern.Natural lithography. Appl.Phys. Lets 41, 377-379, 1982 33 Bottom up 3.1 Chemical3.1.1 chemical vapour deposition (CVD)synthesis of a solid material by chemical reaction of a gaseous precursor or mixture of precursor
36、s, commonly initiated by heatNOTE An example would be the growth of carbon nanotubes from methane gas with catalyst particles.3.1.2 molecular beam epitaxy (MBE)technique of growing single crystals in which beams of atoms or molecules are made to strike a single-crystalline substrate in a vacuum, giv
37、ing rise to crystals whose crystallographic orientation is related to that of the substrateNOTE 1 The beam is defined by allowing the vapour to escape from the evaporation zone to a high vacuum zone through a small orifice.NOTE 2 Nanostructures can be grown in this method by exploiting strain, e.g.,
38、 InAs dots on GaAs substrate. McGraw-Hill Dictionary of Scientific and Technical Terms 4PAS 135:20074 BSI 20073.2 Solution templated3.2.1 hardtemplate whose shape remains fixed during processingNOTE An example of this is a self-assembled array of uniformly sized glass or polymer microbeads.3.2.2 sof
39、ttemplate whose shape can change during processing, while retaining the desired geometric relationship, e.g. periodicity NOTE An example of this is a lyotropic liquid crystal template. 3.3 Solution non-templated3.3.1 radiation track etchingformation of a nanostructure by etching along the pathways f
40、ormed by radiation damage in a solid NOTE An example of this is a porous polymer in which tracks are etched using a selective solvent that only dissolves short chains.3.3.2 anodic etching removal of material by application of a positive electrical potential to a metal in a suitable electrolyte solut
41、ion NOTE 1 The formation of a nanostructured porous material is due to the focusing of current density at the thinnest points in a passivating oxide, which generally form a quasi-periodic array that have been created by the radiation. NOTE 2 Examples are anodic etching of porous silicon and alumina
42、that leaves nanosize openings in the material.3.3.3 sol-gel processingproduction process involving the conversion of a sol to a gel, which is then desiccated to produce particles or a film NOTE A thin layer of the sol deposited on a substrate continues to react until the degree of cross-linking tran
43、sforms the sample into a solid-like gel. The latter maybe heated to remove volatile products so forming a hard solid film. derived from PAS 71:2005, definition 6.233.3.4 electroplatingdeposition of a film by application of electric current between an electrically conducting substrate and an electrol
44、yte containing a solution of a compound that can be reduced or oxidized to form a solid film on the substrate surface4 Top down 4.1 Mechanical4.1.1 Primary lithography direct writing4.1.1.1 scanning probe microscopy (SPM) method in which a probe is scanned over the surface of a sample, usually coupl
45、ed to a feedback loop. A generic term for all devices using physical interaction between a probe tip and a sample surface for sub-micrometer imaging BSI 2007 5PAS 135:2007NOTE 1 Amongst this family the following can be used for nanofabrication, for example, the physical probe can be used to move or
46、place atoms on a surface, change the chemistry of a surface, or remove material from a surface in a controlled manner leaving a textured surface.NOTE 2 Established types of scanning probe microscopy that can be used for nanofabrication include: AFM (Atomic Force Microscopy); MFM (Magnetic Force Micr
47、oscopy) ; SNOM (Scanning Near-field Optical Microscopy (or NSOM Near Field Scanning Optical Microscopy); SECM (Scanning Electrochemical Microscopy); STM (Scanning Tunneling Microscopy).4.1.1.2 scanning tunneling microscopy (STM)technique for revealing the apparent electron-density-related atomic str
48、ucture of surfaces, using a needle-like probe near the object under observation; a tunneling current, which is measured, is generated by altering the potential at the tip of the probe; a 3D representation of the sample surface is generated by rastering the tip over the surface of the object and mapp
49、ing the distance for constant current level at various pointsNOTE STMs have also been used to produce changes in the molecular composition of substances.PAS 71:2005, definition 10.284.1.1.3 atomic force microscopy (AFM)technique for imaging surfaces by mechanically scanning their surface contours using a microfabricated probe, in which the deflection of a sharp tip sensing the surface forces, mounted on a soft cantilever, is monitored as the tip is moved across the surfaceNOTE Part of the family of mi
