Imagewise Exposure Research Articles

Sugar-Functional Vinyl Addition Poly(norbornene)-Photopatternable Poly(norbornenyl gluconamide) Compositions Developed with Water.

The norbornenyl gluconamide (NBGA) monomer can be polymerized by a number of palladium catalysts to give water-soluble, vinyl addition poly(NBGA). Depending on the catalyst used, the reaction conditions, and the chain-transfer additives employed, high-molecular-weight polymers can be obtained. These polymers can be thermally cross-linked at ca. 190 °C or at ca. 150 °C when the difunctional glutaraldehyde is added. A photopatternable composition is formed by the addition of a water-soluble diazide when the poly(NBGA) molecular weight is sufficiently high. After image-wise exposure, negative-tone patterns are revealed by water development. A detailed analysis of NBGA monomer structures by high-resolution nuclear magnetic resonance techniques including pure shift is reported showing that two diastereomers of each endo- and exo-isomer are formed from the reaction of norbornene methylamine and δ-gluconolactone.

Selective Microsphere Adsorption and Metallization on Photopatterned Polycation Single-layered Adsorption Films

Multivalent cationic molecular and macromolecular adsorbates with plural pyridinium groups were adsorbed irreversibly on a substrate surface taking a negative charge, giving their single-layered adsorption film showing high desorption resistance toward deionized water. The desorption resistance of the adsorbates toward aqueous electrolyte solutions could be controlled by photochemical means such as photodimerization and photodegradation. The desorption suppression and promotion by the photochemical means was due to increasing and decreasing the number of cationic adsorption sites per molecule, respectively. Positive- and negative-type micropatterning, consisting of the surface adsorption, the imagewise exposure, and the development, could be carried out on the basis of the desorption promotion and suppression. The photopatterned adsorption films were available as templates for selective microsphere adsorption and metallization by electroless deposition. In this review, the recent studies done by the author and coworkers were described.

21.3: A New Patterning Method for Full‐Color Polymer Light‐Emitting Devices: Laser Induced Thermal Imaging (LITI)

AbstractWe have developed a new color patterning method for the patterning of full color polymer light‐emitting devices. Laser Induced Thermal Imaging (LITI) involves the imagewise exposure of a thermal transfer film with a scanning near infrared laser. During the process, light emitting polymer (LEP) is transferred from a thermal film to a circuitized substrate. Using the technology, we fabricated a 3.6″ QVGA full color active matrix polymer light‐emitting device (PLED).

A New Photoresist Based on Poly(propyleneimine) Dendrimer.

Poly(propyleneimine)-based alkaline soluble dendrimer 2 was prepared by the Michael addition reaction of poly(propyleneimine) dendrmer (PPID) with N-(2-hydroxy-5-methylphenyl)-2-propenamide. The obtained2 was well-dissolved in common organic solvents and its film was transparent above 300nm. The dissolution behavior of the 2 film containing 30wt% of 1-{1, 1-bis[4-(2-diazo-1(2H)naphthalenone-5-sulfonyloxy)-phenyl]ethyl}-4-{1-[4-(2-diazo-1(2H)naphthalenone-5-sulfonyloxy)phenyl]-methylethyl}-benzene (DNQ) after exposure was studied and it was found that the conventional base developer, a 2.38wt% aqueous tetramethylammonium hydroxide TMAH solution was too alkaline to obtain sufficient dissolution contrast. Therefore, a diluted TMAH developer [0.7wt%] was used for the positive-type system. Then an unexposed area was completely insoluble, on the other hand an exposed area showed an adequate dissolution rate. The photoresist system containing 30wt% ofDNQ showed a sensitivity of 80 mJ/cm2 and a contrast of 5.3 with 365nm light. A series of process, that is, imagewise exposure, heat treatment, flood exposure, and development for the resist system resulted in negative-type image.

Ultraviolet self-generating relief micro-optical elements through crosslinking photopolymerization of liquid resins

The use of a self-processing dry photopolymer layer capable of memorizing optical information as a local change in thickness, is proposed for the fabrication of microlenses, binary holograms and gratings. Relief micro-optical elements are generated by direct imagewise exposure through a mask. A gradient of chemical composition and a gradient of surface free energy cause the transfer of reactive species between dark and illuminated areas. Contrary to conventional lithographic techniques that require wet chemical post-treatment to remove parts of the photoresist material, the fully self-processing character of this technique makes the record available in situ and immediately after exposure.

Further developments for 193 nm top surface imaging resist

Top surface imaging [TSI] resists have been the subject of sporadic interest over the last decade. Their advantages include improved depth of focus, and the ability to print high aspect ratio features with minimal reflectivity and topographic effects. However, further improvements are needed before this approach satisfies all major IC production requirements. A simple, positive tone TSI process for selective silylation of poly (p-hydroxystyrene), PHS, using 193 nm exposure wavelength has been reported. 1.2 This is a non-chemically amplified approach wherein imagewise exposure causes direct polymer crosslinking, sufficient to allow excellent selectivity during the subsequent silylation step. Poly (p-hydroxystyrene) has demonstrated the best performance for TSI thus far. The resulting images are robust enough to withstand standard IC manufacturing processes. However, photosensitivity for this process is ∼ five-fold slower than desired. This paper describes ongoing work to correct this critical deficiency. We are characterizing substituent effects for various functionality, including poly-hydroxy, nitro, chloro, chloromethyl and methyl moieties on p-hydroxystyrene, in the effort to improve our TSI 193 nm process photospeed. Initial results reported here for poly (2,4-dihydroxystyrene), 2,4-PDHS, indicate that aromatic substitution and molecular weight play significant roles in affecting both crosslinking photosensitivity and silylation rate. In support, we will present E s photospeed, silylation rate and imaging data.

Photoreversible optical nonlinearities of polymeric films containing spiropyran with long alkyl chains

It was demonstrated that the third-order optical nonlinearity of polymer films could be reversibly controlled by the photochromic conversion and following J-aggregate formation of spiropyran embedded in an inert polymer matrix. Patterns consisting of areas with high and low third-order nonlinear optical activities were prepared by imagewise exposure of the photochromic films followed by thermal treatment to form thermally stable J aggregates of photoinduced merocyanine in the exposed area. This system could be useful in developing new unconventional optical devices based on optical nonlinearities, including new types of spatial light modulators.

論文特集「有機・無機の光機能材料」 接触界面における光誘起帯電に関する研究 第２報 光重合性感光層と金属の接触界面における光誘起帯電

The behavior of electrification induced by light at the contact interface between a photopolymerizable layer and metal films was studied with the aim of developing a novel photofunctional material. Surface potentials from 10 V to 500 V were induced on the photopolymerized layer by peeling off the contact metal film after imagewise exposure, depending on the work function (3.63-5.1 eV) of the metals. The behavior of this photoinduced electrification, however, can not be accounted for by the contact charging model unlike the case that insulator films are used as contact materials.Some experimental results suggest that this photoinduced electrification is attributed to the charge transfer involving the reaction of a metal and the radicals produced photochemically in the photosensitive layer.

Improvement of the DESIRE process using PROMOTE technology

By application of the PROMOTE technology in the DESIRE process the silicon profiles in the silylated images are improved. The method is based upon photochemical esterification that is limited to the upper part of the resist layer.An additional advantage is that a much lower imaging dose is required. Thus, not only is the silylation limited to the top, but also the imagewise exposure does not penetrate to the bottom.

A novel positive resist for deep UV lithography

AbstractA novel positive resist was prepared by sensitizing poly(p‐trimethylsilyloxystyrene) with p‐nitro‐benzyl‐9, 10‐diethoxyanthracene‐2‐sulfonate (NBAS) which was found to be a deep UV bleachable acid precursor. The silylated polymer is converted to alkaline soluble poly(p‐hydroxy‐styrene) in the presence of acid and a small amount of water. The photoresist gives high resolution positive patterns on imagewise exposure with deep UV light with a sensitivity of 15 mJ/cm2.

Polymere in der drucktechnik

AbstractThree main processes are used in the printing industry: Letterpress, Lithography and Gravure printing.In the early fifties polymer coatings have been introduced in lithographic printing plates formulations. Later, similar systems have proved to be suitable for letterpress, and very recently for gravure printing layers, too.Most polymer formulations used in printing techniques generally have the following features in common:• They are light sensitive• They are coated on to a flat substrate• After imagewise exposure the more soluble areas of the coatings are removed in a development step.The requirements for the polymers used in printing layers are as different as the characteristics of each individual printing process.• The importance of the specific optical properties of the polymers is demonstrated discussing some negative acting light sensitive systems, amongst them the photopolymerisation of monomers.

Dry developed negative resist in synchrotron radiation lithography

The examination of synchrotron radiation (SR) lithography of a dry developable negative resist comprising poly(methylisopropenylketone) and 2,6‐di (4’‐azidobenzylidene)‐4‐methylcyclo hexanone‐1 was carried out using the facilities of the storage ring of ETL‐TERAS where the electron energy is 600 MeV, the storage current is 100 mA, the orbital radius is 2 m, and the distance from the source to the sample is 10 m. The results obtained were excellent, i.e., sharp‐shaped and high aspect ratio resist patterns comparable to those of PMMA patterns in SR lithography were easily obtained in a single layer resist with the dry development and contact printing. In the proximity printing, sharp‐shaped patterns were also obtained, but the resolution depends on the conditions of the imagewise exposure although the reproducibility is good. The sensitivities are 1380 mJ/cm2 (approximately equal to PMMA) and 1840 mJ/cm2 in saturation of remaining resist thickness for contact and proximity printings, respectively. The time required for the complete dry development of 4 μm thick resist coatings in an oxygen plasma is only 4 min which is remarkably shorter than the time required for the thick bottom layer in the trilevel process [53 min for 4 μm; Matsui and Endo, Microelectron. Eng. 1, 51 (1983)].

Organic photoconductors in electrophotography

The latent image formation in electrophotography is accomplished by the imagewise exposure of a corona-charged photoconductor film. Organic photoconductors are finding increased application in electrophotography as a result of dramatic strides made in the identification and invention of new materials. The photogeneration and transport functions are separated in a dual layer concept in which a thin layer of an efficient photoconductive pigment is coated onto a thicker layer capable of transporting charge. A further refinement is the concept of molecular doping of inert binders to enable the charge transport function. A great variety of efficient photoconductive systems may be produced by combining different pigments with molecularly doped transport layers.

Profile modification of resist patterns in optical lithography

AbstractA method is described to modify profiles of resist patterns in novolac and diazo‐oxide containing systems. After patterning of the resist, two successive uniform flood exposures are given, one with deep UV (254 nm) at water‐free conditions and the next with near UV (λ > 300 nm) at normal atmospheric conditions. The profile which results after development is vertical, concave or overhanging depending on flood exposure conditions and development processing. As the method includes a flood near UV exposure at atmospheric conditions the imagewise exposure energy can be reduced to approximately 35 percent of the normal value. Furthermore it gives also the possibility of using the resist as a deep UV resist. Another important implication is that standing wave effects are completely eliminated.

Some Photothermographic Systems

AbstractA number of photothermographic transfer systems have been investigated in which a heat-volatile compontne may be converted into a non-volatile compound by means of a light-induced reaction.The heat-volatile component is coated with an organic light-sensitive compound in a binder on a support. Image-wise exposure of the layer gives a negative image and the residual volatile component is heat transferred onto a receiving sheet containing a colour-forming compound to give a positive image of the original.

Formation and Properties of Sub-Image and Latent-Image Silver Specks Part IlI: Properties of Silver Sub-Specks Produced by Radiation

AbstractSub-image specks have been produced in monodisperse AgBr emulsions by a weak pre-exposure with y-rays, with electrons, and with light at 77 K as well as at room temperature. Coverage of the pre-exposed grains by precipitation of additional AgBr onto the grains or oxidation of the sub-specks at the crystal surfaces led to emulsions which now contained the sub-specks only in the interior of the grains. Upon an image-wise second exposure and surface development all these emulsions showed an increase of the sensitivity in the threshold region of the characteristic curve which can be explained only by an over-all increase of the quantum yield due to capture of holes by the sub-specks. These sub-specks consequently are not precursors of latent image specks and they do not influence latent image topography.Under certain conditions in addition to the former another type of sub-specks (presumably larger in size but still nondevelopable) can be found which do influence latent image topography, which, hence,...