Resist

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

Outlook for 157 nm resist design

Abstract: We have measured the transparencies of a number of candidate resist materials for 157 nm, with an emphasis on determining which chemical platforms would allow resists to be used at maximum thicknesses while meeting requirements for optical density. Although ideal imaging is usually obtained at an optical density between 0.1 and 0.3 and values in excess of 0.5 can often result in nonvertical wall profiles, we chose to arbitrarily choose 0.4 as the maximum tolerable optical density. Using this analysis, our findings show that all existing commercially available resists would need to be <60 nm thick, whereas specialized hydrocarbon resists could be made ∼100 nm thick, and new resists based on hydrofluorocarbons, siloxanes, and/or silsesquioxanes could be engineered to be used in thicknesses approaching 200 nm. We also assess the tradeoff between these thicknesses and what current information exists regarding defects as a function of resist thickness.

Methods for forming thick self-supporting masks

Abstract: A method of constructing a relatively thick, self-supporting mask suitable for electron beam projection processes. Thickness is achieved by multiple steps of coating with resist, exposure, development and plating. First an intermediate or lift off layer is deposited on a substrate. A plating or a cathode layer may then be deposited. Resist is then applied. A first mask layer comprises metal plated in accordance with the first pattern. For the second exposure a geometrically similar pattern is employed to generate larger apertures. Thus, if the first mask layer has 0.20 mil apertures, the second layer might have corresponding 0.21 mil to 0.22 mil apertures. For initial mask patterns of about 2 mil the second layer might be 2.02 mils. If desired, a third exposure can be employed with a third pattern, similar to the first two, but having larger apertures (by 0.02 to 0.03 mils) than the second pattern.

Stereolithographic patterning with interlayer surface modifications

Abstract: Methods for the preparation of multilayered resists include exposure of the a first layer to radiation followed by exposure to an oxidizing agent. The oxidizing agent alters the surface characteristics of the first resist layer such that it is rendered more hydrophilic than the original resist layer. A second layer of resist is then applied to the oxidized surface of the first resist layer and exposed to radiation. This process can be repeated for thousands of coating layers, thereby permitting stereolithographic patterning of parts and construction of micromachines. A final treatment with a dissolution solution will dissolve unwanted resist material. Dependent upon the type of resist material used in the multilayered resist, the dissolution solution can remove the radiation exposed areas, e.g., a positive resist, or remove unexposed areas, e.g., a negative resist.

Self‐developing resist with submicrometer resolution and processing stability

Abstract: Nitrocellulose films have been shown to function as self‐developing resist layers that are sensitive to both low‐energy ( 25:1 have been demonstrated using a stencil mask and an argon ion beam; the resolution obtained was mask limited. The sensitivity of the resist to 2‐keV Ar+ ions is 36 μm/min at beam currents of 1 mA/cm2, allowing exposure times of 1 s for 0.5 μm of resist. The material is capable of functioning as a mask material for typical semiconductor dry etching processes.

Reduction of capillary force for high-aspect ratio nanofabrication

Abstract: The wet processing of SU8 resist was modified in order to achieve a high-aspect ratio patterning with feature size of 100 nm. A final rinse in water, which makes a large contact angle on the resist (less wetting) was added to the procedure. This allowed considerable reduction of the capillary force, which is responsible for pattern distortions in three-dimensional (3D) lithography. 3D recording of high-aspect ratio (far=18) structures by holographic exposure using femtosecond pulses in SU8 resist was achieved using this modified development procedure. The thickness of the free-standing planes was approximately 100 nm. High fidelity of this recording method was confirmed by a Moire pattern transfer into a developed SU8 pattern. In terms of focusing, the 100 nm feature size comprised 1/13-th of the diffraction limit. This modified development is applicable for wet processing when super-critical drying cannot be used.