Y.J. Lee

Dry etching characteristics of ITO thin films deposited on plastic substrates

Abstract The dry etching characteristics of indium-tin-oxide (ITO) films deposited on plastic substrates were studied using Ar/CH4 magnetized inductively coupled plasmas (MICP). When conventional inductively coupled plasmas (ICP) were used, the etch rates of ITO films were generally low. However, by using both the multidipole magnets and the axial electromagnets around the chamber wall of ICP, high ITO etch rates >250 nm/min could be obtained at 90% Ar/10% CH4 with the etch selectivity over photoresist higher than that of the ICP. Atomic force microscopy (AFM) measured as a function of Ar/CH4 showed smoother etched ITO surfaces for most of the etch conditions except for high CH4 conditions such as 70% Ar/30% CH4 which generate hydrocarbon polymer on the etched ITO surface. The surface composition characterized using x-ray photoelectron spectroscopy (XPS) showed preferential losses of ITO components depending on the etch gas composition.

Low-impedance internal linear inductive antenna for large-area flat panel display plasma processing

An internal-type linear inductive antenna, that is, a double-comb-type antenna, was developed for a large-area plasma source having the size of 1020mm×830mm, and high density plasmas on the order of 2.3×1011cm−3 were obtained with 15 mTorr Ar at 5000 W of inductive power with good plasma stability. This is higher than that for the conventional serpentine-type antenna, possibly due to the low impedance, resulting in high efficiency of power transfer for the double-comb antenna type. In addition, due to the remarkable reduction of the antenna length, a plasma uniformity of less than 8% was obtained within the substrate area of 880mm×660mm at 5000 W without having a standing-wave effect.

A study of lead zirconate titanate etching characteristics using magnetized inductively coupled plasmas

Abstract In this study, Pb(Zr 1− x Ti x )O 3 (PZT) thin films were etched using magnetized inductively coupled plasmas (MICP) and their etch characteristics were compared with those by non-magnetized conventional inductively coupled plasmas (ICP). The use of Helmholtz type axial electromagnets around the chamber wall increased the PZT etch rates while decreasing etch uniformity. By using both the multidipole magnets and the axial electromagnets around the chamber wall, the etch uniformity could be improved while maintaining high PZT etch rates. PZT etch rates close to 1700 A/min which are three times higher than those etched using the conventional ICP plasmas could be obtained with optimized MICP conditions. The etch selectivities over Pt at these conditions were higher than 1.5. The MICP used in the experiment showed higher Cl radicals and Cl 2 + /Cl + ratios in the plasmas compared with those in the conventional ICP plasmas. Therefore, the increased chemical and/or physical sputtering by the increased Cl 2 + /Cl + ratios along with the increased chemical reactivity by higher Cl radical densities appears to be responsible for high PZT film etch rates obtained with the MICP in our study. Using the MICP in 90%Cl 2 +10%Ar gas mixture, a nearly vertical etch profile could be also obtained.

Etching characteristics of lead magnesium niobate–lead titanate (PMN–PT) relaxor ferroelectrics

Abstract Etching characteristics of Pb{(Mg 1/3 Nb 2/3 ) 0.9 Ti 0.1 }O 3 (PMN–PT) were studied by an inductively coupled plasma etcher using Ar, Cl 2, and BCl 3 gas combinations. Using Ar/BCl 3 and Cl 2 /BCl 3 , PMN–PT etch rates higher than 2500 A/min could be obtained with the etch selectivity over photoresist higher than 1.0. In general, the increase of BCl 3 in Ar/BCl 3 and Cl 2 /BCl 3 increased etch selectivity without decreasing PMN–PT etch rates significantly. X-Ray photoelectron spectroscopic analysis revealed that, during the PMN–PT etching, Ar ion bombardment enhanced the etching of Pb and Ti components preferentially, BCl 3 plasma enhanced the etching of O, Nb, and Mg components, and Cl 2 plasma enhanced the etching of Pb component. The etched profile angle of PMN–PT increased with the increase of PR selectivity.

Linear internal inductively coupled plasma (ICP) source with magnetic fields for large area processing

A large-area (830=1020 mm) inductively coupled plasma source with internal straight antennas was developed for large area flat panel display (FPD) etch process applications and the effects of magnetic fields employing permanent magnets on the plasma characteristics were investigated. Using straight antennas connected in series without the magnetic field, high-density plasmas on the order of 10 cm could be obtained by applying 1500 W of r.f. power to the antennas. By employing the magnetic fields 11 y3 perpendicular to the antenna currents using permanent magnets, improved plasma characteristics such as increase of ion density and decrease of both electron temperature and plasma potential could be achieved in addition to the stability of the plasma possibly due to the reduction of the electron loss. However, the application of the magnetic field decreased the plasma uniformity slightly even though the uniformity within 10% could be maintained in the 800 mm processing area. 2003 Elsevier Science B.V. All rights reserved.

Effects Of Post Annealing And Oxidation Processes On The Removal Of Damage Generated During The Shallow Trench Etch Process

In this study, 0.3–0.5 µm deep silicon trenches were etched using Cl2/10%N2 and Cl2/50%HBr inductively coupled plasmas, and the defects remaining on the etched silicon trench surfaces and the effects of various annealing and oxidation on the removal of the defects were studied. High resolution transmission electron microscopy was used to investigate the degree of remaining defects and X-ray photoelectron spectroscopy was also used to investigate surface contamination of the etched silicon wafers. Defects were found on the silicon trench surfaces etched using both Cl2/10%N2 and Cl2/50%HBr. A thermal oxidation of 200 A at the temperature up to 1,100°C did not remove the remaining defects completely and more defects were remained on the silicon trench etched using Cl2/10%N2. More defects remaining on the oxidized silicon trench for Cl2/10%N2 appear to be related to the formation of silicon oxynitride on the silicon trench etched in Cl2/10%N2, therefore, forming less thermal oxide during the oxidation process. The annealing of the etched silicon trenches from 900°C to 1,000°C for 30 min in N2 also decreased the number of defects, however, to remove the defects formed in our experiments, the annealings at the temperature higher than 1,000°C in N2 for 30 min appears to be required. A combination process of annealing at 1,000°C and oxidation at 900°C was also effective in removing the defects completely.

Reduction of the electrostatic coupling in a large-area internal inductively coupled plasma source using a multicusp magnetic field

A large area (1020mm×830mm) inductively coupled plasma (ICP) source has been developed using an internal-type linear antenna with permanent magnets forming a multicusp magnetic field. The large rf antenna voltages, which cause the electrostatic coupling between the antenna and the plasma in a large area internal-type linear-antenna ICP source, were decreased significantly by applying the magnetic field near and parallel to the antenna. Through the application of the magnetic field, an approximately 20% higher plasma density, with a value of close to 1.0×1011cm−3 at a rf power of 2000W, and about three times higher photoresist etch rates were observed, while maintaining the plasma nonuniformity at less than 9%.

Etch characteristics of silver by inductively coupled fluorine-based plasmas

In this study, thin films of Ag deposited onto glass substrates were etched using inductively coupled fluorine-based plasmas. The effects of various process conditions on the Ag etch characteristics were evaluated to ascertain whether it would be possible to etch patterned Ag films with high etch rates and smooth sidewalls free of involatile etch products. It was found that involatile etch products remained on the substrate when films were etched in CF4-based gas mixtures possessing either O2 or N2 as an additive. However, when Ar was added to either NF3 or CF4, a residue-free etch was obtained provided the partial pressure of Ar was no less than 50%. It is proposed that the residue-free Ag etch mechanism involves the formation of silver fluoride, which is physically sputtered by Ar+ ions. A Ag etch rate of 160 nm/min with a Ag to photoresist etch selectivity exceeding 1.1 was achieved with an inductive power of 1500 W, a d.c. bias voltage of −180 V and a chamber pressure of 0.8 Pa with 50–50 CF4/Ar partial pressures obtained with 60 sccm CF4/60 sccm Ar flows. In addition, these conditions produced smooth Ag sidewall etch profiles.

Investigation of the outgassing characteristics of the materials comprising a plasma display panel

Long gas evacuation time before the introduction of the discharge gases into the panel is one of the major problems in the production of a plasma display panel (PDP). In this study, the outgassing characteristics during the panel evacuation stage were investigated using a quadrupole mass spectrometer. The origin of the impurity gas was studied by measuring the outgassed species from each layer comprising the PDP. Dominant species observed during the evacuation of the panel were H2, H2O, N2, O2, and CO2 and water vapor was the most abundant species. When the outgassing characteristics of the panel were compared with the outgassing characteristics from each layer comprising the panel, the material most responsible for the water vapor turned out to be a MgO layer. The outgassing experiments of single panels have also shown that the long outgassing time of PDP is mostly related to the MgO layer and possibly also to red, green, and blue layers and white dielectric material coated on the each single panel. Ther...

Dry etch characteristics of Al-Nd films for TFT-LCD

Abstract In this study, Al-Nd thin films deposited on glass were etched using magnetized inductively coupled plasmas and their etch characteristics were investigated as a function of gas combination of Cl 2 /BCl 3 and HBr/BCl 3 , inductive power, bias voltage and pressure. When Cl 2 /BCl 3 gas mixtures were used to etch Al-Nd films, low etch rates close to 1/3 of that of pure Al and etch selectivities over photoresist less than 0.9 were obtained due to the non-volatile Nd in Al-Nd thin films. Also, some residues originating from the remaining Nd were observed on the surface of glass and side wall of the Al-Nd lines after the etching of Al-Nd. However, the use of HBr/BCl 3 gas mixtures increased Al-Nd etch rates and etch selectivities over photoresist, and the highest Al-Nd etch rate close to 140 nm/min and etch selectivity close to 1.1 could be obtained with 50% HBr/50% BCl 3 . In addition, barely no residues and no critical dimensional loss could be found with this etch condition. X-Ray photoelectron spectrometry (XPS) showed preferential removal of Nd by HBr during the Al-Nd etching and preferential removal of Al by Cl 2 and BCl 3 . Therefore, the highest Al-Nd etch rate at 50% HBr/50% BCl 3 appears to be related to the optimal combination of Nd etching with HBr and Al etching with BCl 3.