Low-inductance Antenna Modules Research Articles

Plasma processing of soft materials for development of flexible devices

Plasma-polymer interactions have been studied as a basis for development of next-generation processing of flexible devices with soft materials by means of low-damage plasma technologies (soft materials processing technologies). In the present article, interactions between argon plasmas and polyethylene terephthalate (PET) films have been examined for investigations of physical damages induced by plasma exposures to the organic material via chemical bonding-structure analyses using hard X-ray photoelectron spectroscopy (HXPES) together with conventional X-ray photoelectron spectroscopy (XPS). The PET film has been selected as a test material for investigations in the present study not merely because of its specific applications, such as a substrate material, but because PET is one of the well defined organic materials containing major components in a variety of functional soft materials; C–C main chain, CH bond, oxygen functionalities (O=C–O bond and C–O bond) and phenyl group. Especially, variations of the phenyl group due to argon plasma exposures have been investigated in the present article in order to examine plasma interactions with π-conjugated system, which is in charge of electronic functions in many of the π-conjugated electronic organic materials to be utilized as functional layer for advanced flexible device formations. The PET films have been exposed to argon plasmas sustained via inductive coupling of RF power with low-inductance antenna modules. The HXPES analyses exhibited that the degradations of the oxygen functionalities and the phenyl group in the deeper regions up to 50 nm from the surface of the samples were insignificant indicating that the bond scission and/or the degradations of the chemical bonding structures due to photoirradiation from the plasma and/or surface heating via plasma exposure were relatively insignificant as compared with damages in the vicinity of the surface layers.

X-Ray photoelectron spectroscopy analysis of plasma–polymer interactions for development of low-damage plasma processing of soft materials

Plasma–polymer interactions have been investigated using atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS) of polyethyleneterephthalate (PET) films, which have been exposed to argon plasmas driven by low-inductance antenna modules as a parameter of ion energy. The AFM images indicated that the argon plasma exposure exhibited a significant change in surface roughness. The XPS analyses suggested that the degradation of chemical bonding structure and/or bond scission of PET could be effectively suppressed in the plasma exposures with ion energies below 6 eV. However, significant degradations of O = C–O bond, C–O bond and phenyl group were observed with increasing ion energy above 6 eV.

Development of density-inclination plasmas for analysis of plasma nano-processes via combinatorial method

We have developed a plasma-process analyzer based on the “combinatorial method”, in which process examinations with a continuous variation of sample-preparation conditions can be carried out in one execution of experiment via placing substrates on a substrate holder with an inclined distribution of process parameters (ion flux and radical flux) and the distributions of particle fluxes are finely controlled and characterized via particle diagnostics. In the present study, plasma-fluid simulations have been performed to show the feasibility of the combinatorial plasma-process analyzer, in which density inclinations of the plasma parameters (ion density, radical density) are obtained via sustaining plasmas by localized deposition of discharge power using low-inductance antenna modules. The simulation results showed that density-inclination plasmas were feasible by localized power deposition for sustaining plasmas, indicating that a variety of process conditions can be efficiently analyzed via placing substrates on a substrate holder, along which process parameters are inclined.

Large-area and low-damage processes for hybrid flexible device fabrications with reactive high-density plasmas driven by multiple low-inductance antenna modules

Plasma generation and control technologies for meters-scale ultra-large-area plasma sources have been developed with multiple low-inductance antenna (LIA) modules, as a promising candidate of ultra-large-area and high-density plasma sources for next-generation processing of hybrid flexible devices. Properties of argon-oxygen mixture plasmas sustained with multiple LIA units have been investigated and surface modifications of polymer substrates using the plasmas have been performed. Ion energy distribution at the sheath edge of the argon-oxygen mixture plasmas showed considerable suppression of ion energies as small as or less than 10 eV. We have examined effect of plasma exposure on surface modification and/or degradation of polymer. Surface analysis of polytetrafluoroethylene (PTFE) exhibited nano-surface modification of the polymer surface without suffering degradation of molecular structures beneath the nano- surface layer.

Simulation-Aided Designing of Meter-Scale Large-Area Plasma Source with Multiple Low-Inductance Antenna Modules

The plasma profiles in a 300 cm rectangular plasma source sustained with multiple low-inductance antenna (LIA) modules were investigated using a fluid-simulation code. The profiles of argon plasmas sustained with two LIA modules were investigated in order to evaluate the appropriate spacing between LIA modules for obtaining uniform plasmas in multiple antenna configurations. For designing meter-scale large-area plasma sources, the simulation in the rectangular chamber with multiple LIA modules was carried out. Argon ion (Ar+) and metastable radical neutral (Ar*) distributions with a nonuniformity of <6.0% in a 220 cm rectangular area were obtained with the proper arrangement of antenna modules.

Large-area low-damage plasma sources driven by multiple low-inductance-antenna modules for next-generation flat-panel display processes

Plasma-generation and profile-control technologies for ultra-large-area processing of flat-panel displays have been developed by employing multiple low-inductance antenna (LIA) modules to sustain meter-scale inductively-coupled plasmas, as a promising candidate for high-density (1011–1012 cm−3) plasma sources as well as high-quality (low-damage) plasma processing. Our proposal of the unique source configuration is based on the principle of multiple operation and integrated control of LIA modules. Each of the LIA modules consists of a U-shaped internal antenna with a scale-length much smaller than 1/4 wavelength of the high-frequency power transmission to avoid problems associated with standing-wave effects. Furthermore, for active control of power-deposition profiles to attain desired plasma distributions, each of the LIA modules is equipped with an independent RF power amplifier. Experiments with a meter-scale reactor demonstrated achievements of high plasma densities above 1011 cm−3 in argon and uniformity control capabilities. The results indicated that the plasma production and/or control technologies with the LIA modules are promising for a variety of FPD processes.

21406 マルチアンテナ型RFプラズマによるメートル級大面積での低ダメージプロセスと制御(基調講演,デバイス&配線技術2,OS.1 機械工学が支援する微細加工技術(半導体・MEMS・NEMS),学術講演)

21406 マルチアンテナ型RFプラズマによるメートル級大面積での低ダメージプロセスと制御(基調講演,デバイス&配線技術2,OS.1 機械工学が支援する微細加工技術(半導体・MEMS・NEMS),学術講演)

Ultra-Large Area RF Plasma Sources Employing Multiple Low-Inductance Internal-Antenna Modules for Flat Panel Display Processing

Plasma-generation and control technologies for meters-scale ultra-large-area RF plasma sources have been developed with multiple low-inductance antenna (LIA) modules, as a promising candidate of ultra-large area and high-density (1011-1012 cm-3) plasma sources for next-generation large-area processing. The present technologies are based on principle of multiple operation and integrated control of LIA modules, which enables effective control of power deposition profiles and hence the plasma uniformity over meters-scale large area for processing. This paper presents issues in designing ultra-large-area plasma sources to demonstrate feasibility of the uniform sources with 3m x 3m scales to meet requirements in the next-generation processes.

Development of Large Area Plasma Reactor Using Multiple Low-Inductance Antenna Modules for Flat Panel Display Processing

This article reports characteristics of plasmas sustained with LIA modules and profile control capabilities. Experiments with a meter-scale reactor demonstrated uniform plasma production to attain densities as high as 5x1011 cm-3 at an argon pressure of 1.3 Pa and an RF power of 4 kW. Design issues for large-area plasma sources with a scale-size of 3 m were also presented to exhibit the feasibility of novel large-area plasma sources to meet the requirements of the next-generation meters-scale processing.

Production and Control of Large-Area Plasmas for Meters-Scale Flat-Panel-Display Processing with Multiple Low-Inductance Antenna Modules

Plasma technologies for meters-scale flat-panel-display (FPD) processing have been developed using multiple low-inductance antenna (LIA) modules to drive inductively coupled plasmas (ICPs), in which RF-power-deposition profiles can be controlled in plasma reactors with a scale as large as meters. The LIA module consisted of a U-shaped internal antenna with dielectric isolation, each of which was coupled to an RF power system for independent power control of driving ICP. Our new proposal of the unique source configuration is based on the principle of multiple operation and integrated control of LIA modules, which allow low-voltage high-density plasma production with active control of power deposition profiles. Multiple LIA modules mounted on the wall of a discharge chamber were independently controlled to attain the desired plasma profiles. Experiments with a meter-scale rectangular reactor resulted in stable source operation to attain high densities >1011 cm−3. Plasma-enhanced chemical vapor deposition of amorphous hydrogenated carbon films showed an excellent control capability of film-thickness distributions to achieve the film-thickness uniformity of 8.6%, which was defined as the value of (maximum thickness − minimum thickness) divided by the average thickness over the substrate area of 410 mm × 520 mm. The obtained results indicate that the plasma production and/or control technologies with the LIA modules are quite attractive as a high-density low-potential plasma source for a variety of FPD processes.