Abstract: Example methods may provide a thin film etching method. Example thin film etching methods may include forming a Ga—In—Zn—O film on a substrate, forming a mask layer covering a portion of the Ga—In—Zn—O film, and etching the Ga—In—Zn—O film using the mask layer as an etch barrier, wherein an etching gas used in the etching includes chlorine. The etching gas may further include an alkane (CnH2n+2) and H2 gas. The chlorine gas may be, for example, Cl2, BCl3, and/or CCl3, and the alkane gas may be, for example, CH4.

Abstract: A method of etching silicon-and-carbon-containing material is described and includes a SiConi™ etch in combination with a flow of reactive oxygen. The reactive oxygen may be introduced before the SiConi™ etch reducing the carbon content in the near surface region and allowing the SiConi™ etch to proceed more rapidly. Alternatively, reactive oxygen may be introduced during the SiConi™ etch further improving the effective etch rate.

Abstract: A method of manufacturing a dot pattern includes the steps of preparing a structured material composed of a plurality of columnar members containing a first component and a region containing a second component different from the first component surrounding the columnar members, with the structured material being formed by depositing the first component and the second component on a substrate, and removing the columnar members from the structured material to form a porous material having a columnar hole. In addition, a material is introduced into the columnar hole portions of the porous material to form a dot pattern, and the porous material is removed.

Abstract: The present invention is an etching method for performing an etching process in the presence of a plasma on an object to be processed in which a layer to be etched made of a tungsten-containing material is formed on a base layer made of a silicon-containing material in a process vessel capable of being evacuated to create therein a vacuum, wherein a chlorine-containing gas, an oxygen-containing gas, and a nitrogen-containing gas are used as an etching gas for performing the etching process.

Abstract: In some implementations, a method is provided in a plasma reactor for etching a trench in an organic planarization layer of a resist structure comprising a photoresist mask structure over a hardmask masking the organic planarization layer. This may include introducing into the plasma reactor an etchant gas chemistry including N2, H2, and O2 and etching a masked organic planarization layer using a plasma formed from the etchant gas chemistry. This may include etching through the planarization layer to form a trench with a single etch step.

Abstract: Provided are a wafer through silicon via (TSV) forming method and equipment therefor. The wafer TSV forming method includes the operations of arranging a wafer having a front surface having a circuit area patterned thereon; recognizing locations of bond pads in the circuit area of the front surface of the wafer by using an image recognition camera, and converting the recognition of the locations into bond pad location information with respect to a back surface of the wafer; flipping the wafer; forming etching holes with middle depth in the back surface of the wafer by using a laser in a manner to match the locations of the bond pads by using the bond pad location information from the image recognition camera; and performing a plasma isotropic etching on the back surface having formed therein the etching holes with middle depth, thereby forming TSVs penetrating the bond pads.

Abstract: A semiconductor process and apparatus uses a predetermined sequence of patterning and etching steps to etch a gate stack (30, 32) formed over a substrate (36), thereby forming an etched gate (33) having a vertical sidewall profile (35). By constructing the gate stack (30, 32) with a graded material composition of silicon-based layers, the composition of which is selected to counteract the etching tendencies of the predetermined sequence of patterning and etching steps, a more idealized vertical gate sidewall profile (35) may be obtained.

Abstract: Provided are an etching method for a multi-layered structure of semiconductors in groups III-V and a method of manufacturing a VCSEL using the etching method. According to the etching method, a stacked structure including a first semiconductor layer and a second semiconductor layer is exposed to a plasma of a mixture consisting of Cl2, Ar, CH4, and H2 to etch the stacked structure, so that a mirror layer of the VCSEL is formed. The first semiconductor layer is formed of a semiconductor in groups III-V and the second semiconductor layer is formed of a semiconductor in groups III-V, other than the semiconductor of the first semiconductor layer. At least part of a lower mirror layer, a lower electrode layer, an optical gain layer, an upper electrode layer, and an upper mirror layer is etched using one time of an etching process, so that a clean and smooth etched surface is obtained.

Abstract: A wafer support pin has a front end contacted with a wafer such that the front end is flat or rounded. Thus, gravitational stress is minimized during annealing the wafer, thereby minimizing slip dislocation. This wafer support pin is suitably used for annealing of a wafer, particularly high temperature rapid thermal annealing of a large-diameter wafer.

Abstract: An electron-emitting device comprises a pair of electrodes and an electroconductive film arranged between the electrodes and including an electron-emitting region carrying a graphite film. The graphite film shows, in a Raman spectroscopic analysis using a laser light source with a wavelength of 514.5 nm and a spot diameter of 1 ?m, peaks of scattered light, of which 1) a peak (P2) located in the vicinity of 1,580 cm?1 is greater than a peak (P1) located in the vicinity of 1,335 cm?1 or 2) the half-width of a peak (P1) located in the vicinity of 1,335 cm?1 is not greater than 150 cm?1.

Abstract: An etching method forms a metal-fluoride layer at a temperature of 150° C. or higher at least as a part of an etching mask formed over a semiconductor layer; patterns the metal-fluoride layer; and etches the semiconductor layer using the patterned metal-fluoride layer as a mask. According to the etching method, an etching-resistant semiconductor layer such as a Group III-V nitride semiconductor can be easily etched by a relatively simpler process.

Abstract: There are provided an inspection method of a compound semiconductor substrate that can have the amount of impurities at the surface of the compound semiconductor substrate reduced, a compound semiconductor substrate, a surface treatment method of a compound semiconductor substrate, and a method of producing a compound semiconductor crystal. In the inspection method of the surface of the compound semiconductor substrate, the surface roughness Rms of the compound semiconductor substrate is measured using an atomic force microscope at the pitch of not more than 0.4 nm in a scope of not more than 0.2 ?m square. The surface roughness Rms of the compound semiconductor substrate measured by the inspection method is not more than 0.2 nm.

Abstract: In a method of fabricating a semiconductor device, an additive gas is mixed with an etching gas to reduce a fluorine ratio of the etching gas. The etching gas having a reduced fluorine rate is utilized in the process for etching a nitride layer formed on an oxide layer to prevent the oxide layer formed below the nitride layer from being etched along with the nitride layer. The method comprises primarily etching an exposed charge storage layer using an etching gas; and secondarily etching the charge storage layer using the etching gas under a condition that a ratio of fluorine contained in the etching gas utilized in the secondary etching step is less than a ratio of fluorine contained in the etching gas utilized in the primary etching step. Thus, the tunnel insulating layer formed below the charge storage layer is not damaged when the charge storage layer is patterned.

Abstract: The invention relates to a method for manufacturing chips composed of at least one electrically conductive material. Such a method comprises the following steps: deposition, on a support, of an alloy comprising at least the electrically conductive material and a second material; exposure of the alloy to plasma etching, in order to cause the desorption of the materials of the alloy not forming part of the composition of the chips, that is at least the second material but not the electrically conductive material; formation of chips composed of at least said electrically conductive material.

Abstract: A method and arrangement for treating a substrate processed using a laser beam, wherein said substrate comprises at least a body of semiconductor material. The method comprises a step of etching said substrate for removing from said body of semiconductor material recast material deposited on said body during said laser processing. The step of etching is controlled for removing in addition to said recast layer, at least a part of said semiconductor material of said body for improving mechanical strength of said substrate.

Abstract: A method of manufacturing a silicon carbide semiconductor device includes forming a trench for a MOS gate in an SiC substrate by dry etching. Thereafter, the substrate with the trench is heat treated. The heat treatment includes heating the substrate in an Ar gas atmosphere or in a mixed gas atmosphere containing SiH4 and Ar at a temperature between 1600° C. and 1800° C., and thereafter in a hydrogen gas atmosphere at a temperature between 1400° C. and 1500° C. The present manufacturing method smoothens the trench inner surface and rounds the corners in the trench to prevent the electric field from localizing thereto.

Abstract: The invention provides a laser etching method for optical ablation working by irradiating a work article formed of an inorganic material with a laser light from a laser oscillator capable of emitting in succession light pulses of a large energy density in space and time with a pulse radiation time not exceeding 1 picosecond, wherein, in laser etching of the work article formed of the inorganic material by irradiation thereof with the laser light from the laser oscillator with a predetermined pattern and with a predetermined energy density, there is utilized means for preventing deposition of a work by-product around the etching position.

Abstract: A method for manufacturing a semiconductor device includes forming a SiGe layer on a Si substrate, forming a dummy pattern to expose a surface of the Si substrate, and wet etching the SiGe layer while an etchant is contacted with, the dummy pattern.

Abstract: Some embodiments include methods of recessing multiple materials to a common depth utilizing etchant comprising C4F6 and C4F8. The recessed materials may be within isolation regions, and the recessing may be utilized to form trenches for receiving gatelines. Some embodiments include structures having an island of semiconductor material laterally surrounded by electrically insulative material. Two gatelines extend across the insulative material and across the island of semiconductor material. One of the gatelines is recessed deeper into the electrically insulative material than the other.

Abstract: Films of III-nitride for semiconductor device growth are planarized using an etch-back method. The method includes coating a III-nitride surface having surface roughness features in the micron range with a sacrificial planarization material such as an appropriately chose photoresist. The sacrificial planarization material is then etched together with the III-nitride roughness features using dry etch methods such as inductivel coupled plasma reactive ion etching. By closely matching the etch rates of the sacrificial planarization material and the III-nitride material, a planarized III-nitride surface is achieved. The etch-back process together with a high temperature annealing process yields a planarize III-nitride surface with surface roughness features reduced to the nm range. Planarized III-nitride, e.g., GaN, substrates and devices containing them are also provided.

Abstract: A thin film transistor has a semiconductor thin film including zinc oxide, a protection film formed on entirely the upper surface of the semiconductor thin film, a gate insulating film formed on the protection film, a gate electrode formed on the gate insulating film above the semiconductor thin film, and a source electrode and drain electrode formed under the semiconductor thin film so as to be electrically connected to the semiconductor thin film.

Abstract: Embodiments relate to a method for forming a wiring in a semiconductor device, that may include laminating a conductive layer for wiring formation on a semiconductor substrate, forming a photoresist layer pattern on the conductive layer, performing primary dry etching for the conductive layer after employing the photoresist layer pattern as a mask, thereby forming a wiring pattern, partially removing the photoresist layer pattern through secondary dry etching, thereby forming a passivation layer on a surface of the wiring pattern, performing tertiary dry etching for the wiring pattern and a diffusion barrier after employing the photoresist layer pattern as a mask, thereby forming a metal wiring, and removing the photoresist layer pattern.

Abstract: An aluminum gallium nitride/gallium nitride layer (III-V nitride semiconductor layer) is formed on the surface of a silicone carbide substrate. The aluminum gallium nitride/gallium nitride layer is dry-etched from an exposed surface, using a chlorine-based gas (first gas) and a surface via hole is thereby formed. A back via hole, which is to be connected to the surface via hole, is formed by dry-etching the silicon carbide substrate from an exposed back side using a fluorine-based gas (second gas).

Abstract: A method of manufacturing gate oxide layers with different thicknesses is disclosed. The method includes that a substrate is provided first. The substrate has a high voltage device region and a low voltage device region. Then, a high voltage gate oxide layer is formed on the substrate. Afterwards, a first wet etching process is performed to remove a portion of the high voltage gate oxide layer in the low voltage device region. Then, a second wet etching process is performed to remove the remaining high voltage gate oxide layer in the low voltage device region. The etching rate of the second wet etching process is smaller than that of the first wet etching process. Next, a low voltage gate oxide layer is formed on the substrate in the low voltage device region.

Abstract: A method for manufacturing an optical device includes the steps of: forming a first multilayer film, including forming a first mirror above a substrate, forming an active layer above the first mirror, forming a second mirror above the active layer, forming a semiconductor layer on the second mirror, and forming a sacrificial layer on the semiconductor layer; conducting a first examination step of conducting a reflectance examination on the first multilayer film; forming a second multilayer film by removing the sacrificial layer from the first multilayer film; conducting a second examination step of conducting a reflection coefficient examination on the second multilayer film; and patterning the second multilayer film to form a surface-emitting laser section having the first mirror, the active layer and the second mirror, and a diode section having the semiconductor layer, wherein the sacrificial layer is formed to have an optical film thickness of an odd multiple of ?/4, where ? is a design wavelength of ligh

Abstract: The present invention provides a method of plasma etching with pattern mask. There are two different devices in the two section of a wafer, comprising silicon and Gallium Arsenide (GaAs). The Silicon section is for general semiconductor. And the GaAs section is for RF device. The material of pad in the silicon is usually metal, and metal oxide is usually formed on the pads. The metal oxide is unwanted for further process; therefore it should be removed by plasma etching process. A film is attached to the surface of the substrate exposing the area need for etching. Then a mask is attached and aligned onto the film therefore exposing the area need for etching. Then plasma dry etching is applied on the substrate for removing the metal oxide.

Abstract: The ion beam irradiation apparatus has a vacuum chamber 10, an ion source 2, a substrate driving mechanism 30, rotation shafts 14, arms 12, and a motor. The ion source 2 is disposed inside the vacuum chamber 10, and emits an ion beam 4 which is larger in width than a substrate 6, to the substrate 6. The substrate driving mechanism 30 reciprocally drives the substrate 6 in the vacuum chamber 10. The center axes 14a of the rotation shafts 14 are located in a place separated from the ion source 2 toward the substrate, and substantially parallel to the surface of the substrate. The arms 12 are disposed inside the vacuum chamber 10, and support the ion source 2 through the rotation shafts 14. The motor is disposed outside the vacuum chamber 10, and reciprocally rotates the rotation shaft 14.

Abstract: An improved solution for producing nitride-based heterostructure(s), heterostructure device(s), integrated circuit(s) and/or Micro-Electro-Mechanical System(s) is provided. A nitride-based etch stop layer that includes Indium (In) is included in a heterostructure. An adjacent layer of the heterostructure is selectively etched to expose at least a portion of the etch stop layer. The etch stop layer also can be selectively etched. In one embodiment, the adjacent layer can be etched using reactive ion etching (RIE) and the etch stop layer is selectively etched using a wet chemical etch. In any event, the selectively etched area can be used to generate a contact or the like for a device.

Abstract: An etched grooved GaN-based permeable-base transistor structure is disclosed, along with a method for fabrication of same.

Abstract: A method is provided which includes forming a hardmask feature adjacent to a patterned sacrificial structure of a semiconductor topography, selectively removing the patterned sacrificial structure to expose a lower layer and etching exposed portions of the lower layer in alignment with the hardmask feature. In some embodiments, forming the hardmask feature may include conformably depositing a hardmask material above the patterned sacrificial structure and lower layer as well as blanket etching the hardmask material such that upper surfaces of the patterned sacrificial structure and portions of the lower layer are exposed and portions of the hardmask material remain along sidewalls of the patterned sacrificial structure. The method may be applied to produce an exemplary semiconductor topography including a plurality of gate structures each having a width less than approximately 70 nm, wherein a variation of the widths among the plurality of gate structures is less than approximately 10%.

Abstract: A method of manufacturing a dot pattern includes the steps of preparing a structured material composed of a plurality of columnar members containing a first component and a region containing a second component different from the first component surrounding the columnar members, with the structured material being formed by depositing the first component and the second component on a substrate, and removing the columnar members from the structured material to form a porous material having a columnar hole. Additional steps include introducing a mask material into the columnar hole of the porous material to form a dot pattern, and removing the porous material.

Abstract: To improve the shape of a gate electrode having SiGe, after patterning a gate electrode 15G having an SiGe layer 15b by a dry etching process, a plasma processing (postprocessing) is carried out in an atmosphere of an Ar/CHF3 gas. Thereby, the gate electrode 15G can be formed without causing side etching at two side faces (SiGe layer 15b) of the gate electrode 15G.

Abstract: Methods for forming anisotropic features for high aspect ratio application in etch process are provided in the present invention. The methods described herein advantageously facilitates profile and dimension control of features with high aspect ratios through a sidewall passivation management scheme. In one embodiment, sidewall passivations are managed by selectively forming an oxidation passivation layer on the sidewall and/or bottom of etched layers. In another embodiment, sidewall passivation is managed by periodically clearing the overburden redeposition layer to preserve an even and uniform passivation layer thereon. The even and uniform passivation allows the features with high aspect ratios to be incrementally etched in a manner that pertains a desired depth and vertical profile of critical dimension in both high and low feature density regions on the substrate without generating defects and/or overetching the underneath layers.

Abstract: A method of seasoning an idle silicon nitride etcher is described. A buffer material having stronger adhesion to an internal wall of the chamber of the silicon nitride etcher than silicon nitride is etched in the chamber, so as to form a buffer layer on the internal wall of the chamber. Then, silicon nitride is etched in the chamber to form a layer of SiN-based polymer on the buffer layer.

Abstract: A method for etching a deep trench in a substrate. A multi-layer hard mask structure is formed overlying the substrate, which includes a first hard mask layer and at least one second hard mask layer disposed thereon. The first hard mask layer is composed of a first boro-silicate glass (BSG) layer and an overlying first undoped silicon glass (USG) layer and the second is composed of a second BSG layer and an overlying second USG layer. A polysilicon layer is formed overlying the multi-layer hard mask structure and then etched to form an opening therein. The multi-layer hard mask structure and the underlying substrate under the opening are successively etched to simultaneously form the deep trench in the substrate and remove the polysilicon layer. The multi-layer hard mask structure is removed.

Abstract: A method and apparatus for providing integrated active regions on silicon-on-insulator (SOI) devices by oxidizing a portion of the active layer. When the active layer of the SOI wafer is relatively thick, such as about 200 ? to 1000 ? or greater, the etching process partially removes the active layer. The remaining active layer is oxidized prior to a wet dip for removing the mask layer, preventing the wet dip process from undercutting the active region. When the active layer of the SOI wafer is relatively thin, such as about 25 ? to 400 ?, the partial etching step may be reduced or eliminated. In this case, the active layer is oxidized with little or no etching of the active layer. The exposed active layer is oxidized to prevent the wet dip process from undercutting the active region.

Abstract: A method for forming a step channel of a semiconductor device is disclosed. The method for forming a step channel of a semiconductor device comprises forming a hard mask layer pattern defining a step channel region on a semiconductor substrate, forming a spacer on a sidewall of the hard mask layer pattern, and simultaneously etching the spacer and a predetermined thickness of the semiconductor substrate using the hard mask layer pattern and the spacer as an etching mask.

Abstract: Provided is a dry etching method for an oxide semiconductor film made of In—Ga—Zn—O, in which an etching gas containing a hydrocarbon is used in a dry etching process for the oxide semiconductor film made of In—Ga—Zn—O formed on a substrate.

Abstract: Methods of forming a mask for implanting a substrate and implanting using an implant stopping layer with a photoresist provide lower aspect ratio masks that cause minimal damage to trench isolations in the substrate during removal of the mask. In one embodiment, a method of forming a mask includes: depositing an implant stopping layer over the substrate; depositing a photoresist over the implant stopping layer, the implant stopping layer having a density greater than the photoresist; forming a pattern in the photoresist by removing a portion of the photoresist to expose the implant stopping layer; and transferring the pattern into the implant stopping layer by etching to form the mask. The implant stopping layer may include: hydrogenated germanium carbide, nitrogenated germanium carbide, fluorinated germanium carbide, and/or amorphous germanium carbon hydride (GeHX), where X includes carbon. The methods/mask reduce scattering during implanting because the mask has higher density than conventional masks.

Abstract: There are provided an inspection method of a compound semiconductor substrate that can have the amount of impurities at the surface of the compound semiconductor substrate reduced, a compound semiconductor substrate, a surface treatment method of a compound semiconductor substrate, and a method of producing a compound semiconductor crystal. In the inspection method of the surface of the compound semiconductor substrate, the surface roughness Rms of the compound semiconductor substrate is measured using an atomic force microscope at the pitch of not more than 0.4 nm in a scope of not more than 0.2 ?m square. The surface roughness Rms of the compound semiconductor substrate measured by the inspection method is not more than 0.2 nm.

Abstract: In a method for manufacturing a semiconductor device wherein via holes are formed in an SiC substrate, a stacked film consisting of a Ti film and an Au film is formed on the back face of the SiC substrate, and a Pd film is formed thereon. Then, an Ni film is formed by non-electrolytic plating, using the Pd film as a catalyst. Thereafter, via holes penetrating through the SiC substrate are formed by etching, using the Ni film as a mask.

Abstract: A component delivery mechanism for distributing a component inside a process chamber is disclosed. The component is used to process a work piece within the process chamber. The component delivery mechanism includes a plurality of component outputs for outputting the component to a desired region of the process chamber. The component delivery mechanism further includes a spatial distribution switch coupled to the plurality of component outputs. The spatial distribution switch is arranged for directing the component to at least one of the plurality of component outputs. The component delivery mechanism also includes a single component source coupled to the spatial distribution switch. The single component source is arranged for supplying the component to the spatial distribution switch.

Abstract: The present invention relates to a method for forming a storage node contact of a semiconductor device. The method includes the steps of: depositing sequentially a conductive layer, a nitride layer and a polysilicon layer on a substrate having an insulating structure and a conductive structure; etching selectively the polysilicon layer, the nitride layer and the conductive layer to form a plurality of conductive patterns with a stack structure of the conductive layer and a dual hard mask including the polysilicon layer and the nitride layer; forming an insulation layer along a profile containing the conductive patterns; and etching the insulation layer by using a line type photoresist pattern as an etch mask to form a contact hole exposing the conductive structure disposed between the neighboring conductive patterns.

Abstract: Accordingly, this invention relates to an dry etching process for semiconductor wafers. More particularly, the present invention discloses a dry etching process including a halogen etchant (24) and a nitrogen gas (28) that selectively etches a compound semiconductor material (18) faster than the front-side metal layers (16A)(16B). Further, the dry etching process produces a vertical wall profile on compound semiconductor material (18) in both X (38) and Y (40) crystalline directions without undercutting the top of a via-opening.

Abstract: A plasma etching method includes the step of performing a plasma etching on a silicon-containing dielectric layer formed on a substrate to be processed by using a plasma, while using an organic layer as a mask. The plasma is generated from a processing gas at least including a C6F6 gas, a rare gas and an oxygen gas, and a flow rate ratio of the oxygen gas to the C6F6 gas (an oxygen gas flow rate/a C6F6 gas flow rate) is set to be about 2.8 to 3.3.

Abstract: The present invention is directed to a method of etching a multi-layer structure formed from a layer of a first material and a layer of a second material differing from the first material to obtain a desired degree of planarization. To that end, the method includes creating a first set of process conditions to etch the first material, generating a second set of process conditions to etch the second material; and establishing an additional set of process conditions to concurrently etch the first and second materials at substantially the same etch rate.

Abstract: The present invention includes a process for selectively etching a low-k dielectric material formed on a substrate using a plasma of a gas mixture in a plasma etch chamber. The gas mixture comprises a fluorine-rich fluorocarbon or hydrofluorocarbon gas, a nitrogen-containing gas, and one or more additive gases, such as a hydrogen-rich hydrofluorocarbon gas, an inert gas and/or a carbon-oxygen gas. The process provides a low-k dielectric to a photoresist mask etching selectivity ratio greater than about 5:1, a low-k dielectric to a barrier/liner layer etching selectivity ratio greater about 10:1, and a low-k dielectric etch rate higher than about 4000 ?/min.

Abstract: A ferroelectric memory capacitor is formed by forming a barrier layer, a first metal layer, a ferroelectric layer, a second metal layer, and a hard mask layer, on dielectric layer (70). Using the patterned hard mask layer (255), the layers are etched to form an etched barrier layer (205), and etched first metal layer (215), and etched ferroelectric layer (225), and etched second metal layers (235, 245). The etched layers form a ferroelectric memory capacitor (270) with sidewalls that form an angle with the plane of the upper surface of the dielectric layer (70) between 78° and 88°. The processes used to etch the layers are plasma processes performed at temperatures between 200° C. and 500° C.

Abstract: The present invention discloses a method of manufacturing a liquid crystal display device including a first photolithography process forming a gate electrode on a substrate; a second photolithography process including: a) depositing sequentially a gate insulating layer, first and second semiconductor layers, and a metal layer; b) applying a first photoresist on the metal layer; c) aligning a first photo mask with the substrate; d) light exposing and developing the first photoresist to produce a first photoresist pattern; e) etching the metal layer using a first etchant, the first etchant ashing the first photoresist pattern on a predetermined portion of the metal layer to produce a second photoresist pattern, thereby exposing the predetermined portion of the metal layer; and f) etching the gate insulating layer, the first and second semiconductor layer, and the predetermined portion of the metal layer using a second etchant according to the second photoresist pattern to form source and drain electrodes, an oh

Abstract: The present invention discloses a method of manufacturing a liquid crystal display device including a first photolithography process forming a gate electrode on a substrate; a second photolithography process including: a) depositing sequentially a gate insulating layer, first and second semiconductor layers, and a metal layer; b) applying a first photoresist on the metal layer; c) aligning a first photo mask with the substrate; d) light exposing and developing the first photoresist to produce a first photoresist pattern; e) etching the metal layer using a first etchant, the first etchant ashing the first photoresist pattern on a predetermined portion of the metal layer to produce a second photoresist pattern, thereby exposing the predetermined portion of the metal layer; and f) etching the gate insulating layer, the first and second semiconductor layer, and the predetermined portion of the metal layer using a second etchant according to the second photoresist pattern to form source and drain electrodes, an oh