technology Technology is the application of knowledge to reach practical goals in a specifiable and reproducible way. The word ''technology'' may also mean the product of such an endeavor. The use of technology is widely prevalent in medicine, science, ...

, soft lithography is a family of techniques for fabricating or replicating

structure A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...

s using "elastomeric stamps, molds, and conformable photomasks". It is called "soft" because it uses

elastomer An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of ''elastic p ...

ic materials, most notably

PDMS PDMS may refer to: * Palm Desert Middle School, a middle school in Palm Desert, California * Plant Design Management System * Plasma desorption mass spectrometry * Point-Defence Missile System * Polydimethylsiloxane, a silicon-based organic polymer ...

. Soft lithography is generally used to construct features measured on the micrometer to

nanometer 330px, Different lengths as in respect to the molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American and British English spelling differences#-re ...

scale. According to Rogers and Nuzzo (2005),

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...

of soft lithography expanded rapidly from 1995 to 2005. Soft lithography tools are now commercially available.

Types

PDMS stamp PDMS stamps are pieces of polydimethylsiloxane (PDMS), a silicone, that have been patterned usually against a master mask to form a relief pattern used in soft lithography. This PDMS stamp can be used in either its current form as a relief surfa ...

Microcontact printing Microcontact printing (or μCP) is a form of soft lithography that uses the relief patterns on a master polydimethylsiloxane (PDMS) stamp or Urethane rubber micro stamp to form patterns of self-assembled monolayers (SAMs) of ink on the surface ...

Multilayer soft lithography Multilayer soft lithography (MSL) is a fabrication process in which microscopic chambers, channels, valves and vias are molded within bonded layers of elastomer.Commercial PDMS stampscamold materials such as optical adhesivein a sequential process ...

Advantages

Soft lithography has some unique advantages over other forms of lithography (such as

photolithography In integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer, to protect ...

and

electron beam lithography Electron-beam lithography (often abbreviated as e-beam lithography, EBL) is the practice of scanning a focused beam of electrons to draw custom shapes on a surface covered with an electron-sensitive film called a resist (exposing). The electron b ...

). They include the following: *Lower cost than traditional photolithography in mass production *Well-suited for applications in

biotechnology Biotechnology is the integration of natural sciences and engineering sciences in order to achieve the application of organisms, cells, parts thereof and molecular analogues for products and services. The term ''biotechnology'' was first used b ...

*Well-suited for applications in

plastic electronics Organic electronics is a field of materials science concerning the design, synthesis, characterization, and application of organic molecules or polymers that show desirable electronic properties such as conductivity. Unlike conventional inorga ...

*Well-suited for applications involving large or nonplanar (nonflat) surfaces *More pattern-transferring methods than traditional lithography techniques (more "ink" options) *Does not need a photo-reactive surface to create a nanostructure *Smaller details than

in laboratory settings (~30 nm vs ~100 nm). The resolution depends on the mask used and can reach 6 nm.

Types

Advantages

See also

References

Further reading