Resist

About: Resist is a research topic. Over the lifetime, 40991 publications have been published within this topic receiving 371548 citations.

Plasma etch technologies for the development of ultra-small feature size transistor devices

Abstract: The advances in information and communication technologies have been largely predicated around the increases in computer processor power derived from the constant miniaturization (and consequent higher density) of individual transistors. Transistor design has been largely unchanged for many years and progress has been around scaling of the basic CMOS device. Scaling has been enabled by photolithography improvements (i.e. patterning) and secondary processing such as deposition, implantation, planarization, etc. Perhaps the most important of the secondary processes is the plasma etch methodology whereby the pattern created by lithography is 'transferred' to the surface via a selective etch to remove exposed material. However, plasma etch technologies face challenges as scaling continues. Maintaining absolute fidelity in pattern transfer at sub-16 nm dimensions will require advances in plasma technology (plasma sources, chamber design, etc) and chemistry (etch gases, flows, interactions with substrates, etc). In this paper, we illustrate some of these challenges by discussing the formation of ultra-small device structures from the directed self-assembly of block copolymers (BCPs) where nanopatterns are formed from the micro-phase separation of the system. The polymer pattern is transferred by a double etch procedure where one block is selectively removed and the remaining block acts as a resist pattern for silicon pattern transfer. Data are presented which shows that highly regular nanowire patterns of feature size below 20 nm can be created using etch optimization techniques and in this paper we demonstrate generation of crystalline silicon nanowire arrays with feature sizes below 8 nm. BCP techniques are demonstrated to be applicable from these ultra-small feature sizes to 40 nm dimensions. Etch profiles show rounding effects because etch selectivity in these nanoscale resist patterns is limited and the resist thickness rather low. The nanoscale nature of the topography generated also places high demands on developing new etch processes.

Combined helium ion beam and nanoimprint lithography attains 4 nm half-pitch dense patterns

Abstract: The authors demonstrated a promising technique that yielded single-digit nanometer features for nanotechnology research and possible future electronic circuit fabrication by combining high resolution helium ion beam patterning and nanoimprint lithography. They fabricated a series of line patterns with single-digit nanometer half-pitches by exposing a layer of hydrogen silsesquioxane (HSQ) resist with a scanning focused helium ion beam. The smallest half-pitch of clearly resolved line patterns was 4 nm. Using the HSQ patterns as a nanoimprint template, nanoscale patterns down to 4 nm half-pitch were transferred into nanoimprint resist through a UV-curable nanoimprint process.

Electron beam moiré

Abstract: A method of writing very high frequency line and dot pattems, in excess of 10,000 lines/mm, is described. This method uses a very small diameter, 10 to 20 nm, beam of electrons to sensitize a 100-nm thick layer of electron resist. The line and dot patterns are produced by etching the sensitized resist. Moire fringe patterns occur when the line arrays are observed in the scanning electron microscope. Moire fringes with excellent contrast have been produced at magnifications as high as 1900x. This capability permits e-beam moire to be employed in micromechanics. Examples of line arrays, dot arrays and moire fringe patterns on a brass disk and on a tensile specimen fabricated from glass-fiber-reinforced plastic are demonstrated to introduce the possibilities for micromechanics applications.

Direct 3D Patterning of TiO2 Using Femtosecond Laser Pulses

Abstract: Two-photon polymerization of photosensitive materials irradiated by femtosecond laser pulses is now considered as an enabling technology for the fabrication of 3D structures, especially photonic crystals and photonic crystal templates. Depending on the topology and dielectric constant contrast of photonic crystals, their optical properties can be tailored in a desired manner. Since 1987, when the concept of 3D photonic crystal was introduced by Yablonovitch and John, photonic crystals have been a subject of intensive research. In spite of this, the fabrication of photonic crystals with a full 3D (or omni-directional) bandgap in the visible range is still a challenging task. To realize photonic crystals with a full photonic bandgap, 3D structuring of high refractive index materials is required. The high refractive index (ca. 2.4) and high transparency in the visible spectrum makes TiO2 a very promising photonic material. For many applications, it is desirable to have a simple technique for patterning this material in twoand even three dimensions. Conventionally, TiO2 is patterned by sputtering it onto a pre-patterned organic resist followed by lift-off. When thick films of TiO2 or complicated features are desired, the lift-off process does not work well. For 3D fabrication, the most attractive option so far has been to fabricate templates which were later infiltrated with a high refractive index material, followed by the removal of the original template structure. Another approach is to use inorganic–organic photosensitive materials (ormocers) for the fabrication of photonic crystals. In this case, there exists a possibility to skip the replication steps and to fabricate 3D inorganic structures directly. However, the inorganic content in these materials is not very high and the attempts to fabricate in three dimensions have resulted in porous structures. In order to eliminate the issue of making templates and their subsequent infiltration with a high refractive index material, a direct 3D fabrication of structures appears to be an attractive option. As2S3, a chalcogenide glass, was directly patterned in three dimensions by exploiting its photo-induced metastability. On the other hand, examples of direct patterning of oxides are nonexistent. In this paper, we will demonstrate a direct 3D patterning of TiO2 structures using femtosecond laser pulses. To enable such fabrication, a photosensitive sol– gel-based spin-coatable TiO2 resist was developed. The experimental setup used for the patterning is shown in Figure 1 and is similar to that used before. The TiO2 resist is transparent (refractive index = 1.68) to the femtosecond laser radiation of 780 nm wavelength, and therefore, allows focusing of laser pulses tightly into the material volume. In the focal area, where the intensity of femtosecond laser pulses is high enough to initiate multiphoton processes, bond-breaking in the TiO2 resist makes the irradiated regions insoluble in organic solvents such as acetone. This allows the fabrication of any computer-generated 3D structure by direct laser “recording” into the volume of the TiO2 resist. Because of the threshold behavior and nonlinear nature of this bond-breaking proC O M M U N IC A TI O N