A photosensitive epoxy (PSEP) for multi-mode optical waveguide based on epoxy resins containing fluorene units and photo-acid generator (PAG) has been developed. PSEP is directly patterned by UV irradiation and wet chemical development, avoiding use of photoresist. Fabricated optical waveguides have 50μm width rectangle core pattern, which was smooth sidewalls and surfaces. PSEP optical waveguide exhibits high heat resistance and low optical loss 0.063 μm at 830nm. This simplification of the fabrication process is very attractive in manufacturing optical/electrical devices at low cost.

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Absorption and reflection measurements of polyimides (PIs) PMDA-BAPP, BTDA-BAPP, and CBDA-BAPP were performed using synchrotron radiation as a light source in UV and VUV regions. Absorption spectra were obtained by Kramers-Kronig analyses from reflection spectra. Molecular orbital calculations were performed for model PI compounds. Optical transitions at the absorption tails of aromatic PIs (PMDA-BAPP and BTDA-BAPP) are characteristic of localized electronic transitions of dianhydride units while those at the absorption tail of semi-aromatic PI (CBDA-BAPP) are characteristic of charge transfer transitions. At high-energy regions, phenyl-group π-π* transitions are observed at about 6.2 eV. Very strong absorption peaks are also observed at about 16.0 eV for aromatic PIs and at about 15.0 eV for semi-aromatic PI. These results are characteristic of optical transitions from HOMO-level C 2p orbitals to high-energy region C 2p orbitals above LUMO levels.

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This paper presents the developments of a new high refractive index material that can be used as a light guide in the back-end of CMOS image sensor to achieve optical path improvement and better light collection. Depending on the process conditions, the refractive index of the material can be tuned from 1.6 to 1.8 (RI@633nm). Moreover, this material can be patterned when exposed to i-line leading to a very simple and efficient cost- of-ownership process in the device fabrication flow. Material characteristics as well as patterning performance of a high refractive index precursor material are discussed here in the frame of a 1.4 μm pixel technology development.

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We report a fabrication process for organic field-effect transistors (OFETs) based on stretch-oriented regioregular poly(3-hexylthiophene) (rr-P3HT) film and the anisotropic carrier transport properties in the OFETs. The optical absorption spectra and XRD results indicate that π-conjugated rr-P3HT chains are aligned in the stretching direction with the π-stacking polymer planes parallel to the substrate. The field-effect hole mobility in a current flow parallel to the stretching direction is larger by a factor of 3.4 compared to that perpendicular to the stretching direction. These results indicate that charge transport via the π-conjugated rr-P3HT chains is advantageous in the stretch-oriented rr-P3HT film.

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Desktop type equipment of thermal-assisted UV roller imprinting was developed. A remarkable advantage of the desktop type equipment is expected to be easy evaluation of replication results using different molds with small amounts of resin. Replication tests were carried out under various scanning speed of the stage, UV intensity, and roll temperature. Pattern replication was improved by heating roll under the same scanning speed of stage. Heating of the roll was effective to realize better pattern replication under the same scanning speed of the stage.

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Anisotropic wet etching is widely used in MEMS fabrication processes. As this etching has different etching rates for each crystal lattice face, the etched window shape changes during etching. The fidelity of the mask shape is discussed and a correction method is proposed. It was shown that a rectangle tilted 45 degrees to (110) became octagonal and finally rectangular in shape parallel to (110), while a rectangle parallel to (110) maintained its shape. A circle mask shape also became octagonal and then rectangular. It was demonstrated that deviations from the designed shape that occur during the etching can be corrected on the mask shape in advance. This method is useful for the fabrication of circular etched window shapes.

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Molecular resist material having only one protecting group per molecule (Prot-1) was designed and synthesized. After confirming the structure and purity of Prot-1, Resist-A formulated with Prot-1 as a base material was prepared. Resist-A showed good contrast curve. To confirm the decomposition behavior, Resist-A was analyzed by using High Performance Liquid Chromatography (HPLC) at the exposure dose of E0 value exposed by electron beam (EB). From the HPLC analysis, it was found that the dissolution contrast of Resist-A was caused by deprotection reaction of Prot-1. We evaluated resolution limit of Resist-A by using EB. Resist-A showed 25 nm hp resolution and partially resolving 20 nmhp at the exposure dose of 36 μC/cm2. The mechanism which generates dissolution contrast by the reaction of just one protecting group per molecule would be a key of 22 nmhp generation and beyond at the point of the high resolution property.

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Vertical electron density profiles of various photoresist, top-coat and their combinations as bilayers were obtained from X-ray reflectivity analysis. The result suggests that there are specific layers with different electron density near the surface of photoresists and top-coats films. The investigation on bilayer films which consist of photoresist and top-coat shows that the intermixing of two materials and the roughness of films are varied by annealing (baking) time and temperature.

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Dr. Hiroshi Ito, the inventor of Chemical Amplification Resists for Microlithography, and an IBM fellow, passed away on June 19, 2009. It is a great sadness and large loss for the photoresist society.

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Hierarchical nanostructures are generated on substrates by combining a top-down ion beam lithography with a bottom-up self-assembly of block copolymers. The ion beam lithography images micron sized patterns of block copolymer thin films which contain nanometer sized microdomains. This approach provides a simple route to fabricate structures containing two different length scales, i.e. micrometers and nanometers, which may find a variety of potential applications in nanoscience and technology.

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Photosensitive polyimides (PSPIs) and poly(benzoxazole)s (PSPBOs) are widely utilized as protection and insulating layers in manufacturing semiconductors because of their good mechanical properties, low water absorption, and low dielectric constant. In particular, chemically amplified PSPIs and PSPBOs exhibit very high sensitivity as compared to non-chemically amplified ones. This review article reports the advances in the molecular design of PSPIs and PSPBOs, as well as their potential properties.

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Several techniques have been proposed to achieve higher resolution from 193 nm optical lithography [1]. Most of these techniques require the design of new exposure tools or implementation of costly extra process steps. A new pitch division technique is reported, which doubles the resolution of conventional lithography tools by simply adding one component to the photoresist formulation. This technique creates a resist system that involves a series of linked photochemical reactions (A→B→C) in which a photoacid generator (PAG) produces an intermediate species (B) that is a strong acid, which in turn undergoes a reaction that produces a neutral and inert compound (C) that is the final product. The intermediate acid concentration is low at lower doses, but it is largely consumed at higher doses. At moderate doses, the acid concentration reaches its maximum. This property could, in principle, be exploited to double the frequency of a grating on a mask. One formulation that provides this sort of resist response incorporates both a photoacid generator and a photobase generator. This system was studied by simulation and a test formulation was demonstrated to produce the expected resist response.

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This article is dedicated to late Dr. Ito for his distinguished invention, fantastic technology, and warmhearted humanity
Refractive index lithography was performed on polymer films consist of a photo-acid generator (PAG), t-BOC-protected naphthazarine as an acid chromic dye. The key reaction is the chemically amplified de-protection of the t-BOC group, by which color of the material change followed by refractive index change. Naphthazarine-containing polymer was also prepared. The induced refractive index was as large as 4X10^-3, which is enough large to apply to optical waveguide fabrication.

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