baber/WOPTO huggingface dataset:
Patent KR-20060110913-A (KR)
Title: Method for manufacturing retaining wall and retaining wall manufactured thereof
Inventor: LEE PYOUNG WOO
IPC: E02D17/18
Filed: 2005-04-20
Abstract: A construction method for vegetative reinforced earth is provided to have a stable structure by constructing using a scaffold and a form and tamping sufficiently over all sections regardless of restriction on a gradient, to have effective tensile stress by unifying the whole embankment layers with wires and reinforcements, to reduce the inconvenience of works, the consumption of materials and the loss of soil and to harmonize with surroundings by connecting a wire and a reinforcement directly and inputting a vegetative mat between them. A construction method for vegetative reinforced earth comprises the steps of: placing a form(16) inward and a scaffold(14) outward on the basis of the appointed angle of inclination required for the in-situ ground, and supporting the scaffold and the form using a scaffold fixing pin(18); placing a net(20) and a vegetative mat on the rear of the scaffold and form; placing reinforcements(30a) on the first embankment layer(1a) from the ground, folding up the end of the reinforcement adjacent to the net regularly and connecting the folded end of the reinforcement with the net using wires(24); tamping the first banking layer evenly; forming embankment layers according to the appointed banking height by repeating above mentioned steps; forming a drainage membrane using materials such as non-woven fabrics or broken stones on the rear of an embankment; and dismantling the scaffold and the form and growing plants.
Patent KR-20060111208-A (KR)
Title: System, device, and method for providing slide according to hierarchical structure information
Inventor: PARK HEE CHUN
IPC: G06F3/14
Filed: 2005-04-22
Abstract: A system, a device, and a method for offering slides according to hierarchical structure information are provided to enable a user to understand entire contents of a presentation at a glance by arranging the slides in a hierarchical structure, and enable the user to quickly understand the contents of the presentation by offering an upper slide, and a number and a title of the current slide. A slide position setting part(130) moves the slide to a position set by the user and assigns the hierarchical structure information of the slide to the moved slide. A display part(170) displays the slides or thumbnail slides generated by the user according to the assigned hierarchical structure information and a display mode. The first display screen displays the thumbnail slides according to the hierarchical structure information. The second display screen displays the thumbnail slide placing a pointer among the displayed thumbnail slides.
Patent KR-20060111843-A (KR)
Title: Cylindrical li secondary battery
Inventor: KIM KWANG SU
IPC: H01M50/107
Filed: 2005-04-25
Abstract: Provided is a cylindrical lithium secondary battery that has improved safety against the action of external pressure. The cylindrical lithium secondary battery comprises: a wound electrode assembly including a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate; a core member(500) that has a pipe shape with an incision groove(510) formed along a lengthwise direction and is inserted into a central space of the electrode assembly, wherein at least one end side forming the incision groove(510) has an inclined plane(520); a case having a space for accommodating the electrode assembly; and a cap assembly that combines with the upper part of the case and seals the case.
Patent KR-20060046688-A (KR)
Inventor: JANSEN CRAIG E
IPC: C08G18/10
Filed: 2005-04-26
Abstract: 본 발명은 a), b), 및 c)의 중량을 기준으로 
     a) 2 이상의 반응성 실란기 및 하나 이상의 폴리에테르 세그먼트를 함유한 폴리에테르 우레탄 20 내지 80 중량％, 
     b) 하나의 반응성 실란기 및 하나 이상의 폴리에테르 세그먼트를 함유한 폴리에테르 우레탄 20 내지 80 중량％, 
     c) 15 내지 100 ㎡/g 의 BET 표면적 및 40 내지 110 cc/100 g의 오일 흡수율을 갖는 안료 1 내지 60 중량％를 포함하고,  
     a), b), 및 c)의 합은 100 중량％를 초과하지 않는 접착제, 실란트 또는 코팅 조성물에 관한 것이다.  상기 조성물은 기재 (substrate)를 결합 및(또는) 코팅하는데 사용될 수 있다. 
     폴리에테르 우레탄, 반응성 실란기, 폴리에테르 세그먼트, 접착제, 실란트, 코팅 조성물
Patent KR-20060045864-A (KR)
Inventor: KWAK SANG WOON
IPC: C04B38/02
Filed: 2005-04-29
Abstract: 본 발명은 발포형 케미칼 그라우트재에 관한 것으로, 특히 에폭시 수지, 유리 분말, 충전제, 알칼리 금속계 화합물 또는 알칼리 토금속계 화합물, 금속분말, 경화제, 및 용제를 포함하는 발포형 케미칼 그라우트재, 및 상기 발포형 케미칼 그라우트재를 적용한 구조물의 시공, 보수, 및 보강방법에 관한 것이다. 
     본 발명의 발포형 케미칼 그라우트재는 발포성이 우수하여 특히 천장과 같은 중력과 역방향을 가지는 균열 및 세굴 부위에서 주입 후 발포하여 중력 방향 상부에서 충진성이 뛰어나며 고강도의 폐쇄 기공구조를 가져 압력이나 하중을 받는 장소에서도 충진효과가 우수할 뿐만 아니라, 습식 및 수중환경에서도 추가 공정 없이 단일공정으로 부착성과 작업성이 우수하며, 시공이 쉽고 간편하여 구조물의 시공, 보수, 및 보강에 뛰어난 효과가 있다. 
       
     발포, 그라우트재, 구조물, 보수, 보강
Patent KR-20060114848-A (KR)
Title: Apparatus for suppressing electro-static discharge on dust box used for semiconductor packaging apparatus
Inventor: PARK HWAK KEUN
IPC: H01L21/56
Filed: 2005-05-03
Abstract: An apparatus for suppressing static electricity on a dust box of a semiconductor packaging apparatus is provided to remove the static electricity effectively and to improve installation and removal workability by using a plate type conductive collecting unit. At least one plate type conductive collecting unit(41) is arranged on an inner wall of a dust box(30) of a semiconductor packaging apparatus. A conductor(42) is electrically connected to the conductive collecting unit. A protruded ground(43) is electrically connected to the conductor and is protruded to the outside of the dust box to be electrically grounded to an equipment ground of the outside of the dust box. The conductive collecting unit includes a supporting unit for providing mechanical strength. The supporting unit is made of a conductive material to be electrically connected.
Patent KR-20060045925-A (KR)
Inventor: HAYS CHRISTOPHER A
IPC: G06F17/30
Filed: 2005-05-06
Abstract: 리포트의 열 및/또는 행은 동적 또는 정적인 것 중 하나로서 선언적으로 정의될 수 있다.  선언적 정의는 임의의 마킹에 의해 표현될 수 있다.  열 또는 행은 동적인 것으로 선언적으로 지정된 경우, 복수의 열 또는 행으로 확장될 수 있다.  열 또는 행이 정적인 것으로 지정된 경우, 단일 열 또는 행으로 유지되어 단지 지정된 열 또는 행 데이터만을 표현한다.  열 및 행의 서브그룹은 동적 또는 정적인 것으로 선언적으로 정의될 수 있다.  정적 열 또는 행은 어떠한 서브-열/행을 포함하지 않거나, 복수의 정적 열/행, 복수의 동적 열/행, 또는 양쪽의 임의의 조합을 포함할 수 있다.  유사하게, 동적 열 또는 행은 상기 조합을 포함할 수도 있다. 
       
     리포트 디자인, 유연성, 데이터 관리, 데이터베이스
Patent KR-20060116400-A (KR)
Title: Apparatus for preventing adhesion of powder in vacuum pump
Inventor: KIM JUNG NAM
IPC: H01L21/02
Filed: 2005-05-09
Abstract: An apparatus is provided to prevent the adhesion of powder in a vacuum pump by heating the vacuum pump in a predetermined temperature range using a heating unit and a controller. An apparatus is used for preventing the adhesion of powder in a vacuum pump(40). The apparatus includes a heating unit, a temperature measuring unit, and a controller. The heating unit(110) is used for heating the vacuum pump. The temperature measuring unit(120) is used for measuring the temperature of the inside of the vacuum pump. The controller(130) is used for receiving temperature data from the temperature measuring unit and controlling the heating unit according to the temperature data of the temperature measuring unit.
Patent KR-20060116451-A (KR)
Title: Solar cell module
Inventor: KIM KYUNG JU
IPC: H01L31/042
Filed: 2005-05-10
Abstract: A solar cell module is provided to enhance a module design without the gradation of efficiency of the module itself by coloring along a peripheral portion of a light transmitting part. A solar cell module comprises a solar cell array, resin parts and a first light transmitting part. The solar cell array is composed of a plurality of solar cells arranged into serial and parallel structures. The resin parts are formed at upper and lower portions of the solar cell array. The first light transmitting part(30a) is stably loaded on the resin part. The first light transmitting part is made of a glass material. The first light transmitting part has a colored portion. The colored portion(31) is formed along a periphery of the first light transmitting part to prevent a bus bar of the solar cell array from being exposed to the outside and improve the design of the solar cell module itself.
Patent KR-20060119080-A (KR)
Title: Food and drink packing vessel
Inventor: CHO DONG SUNG
IPC: B65D1/14
Filed: 2005-05-18
Abstract: A food and drink packing vessel is provided to remove the difference in pressure between the inside and outside of the packing vessel by punching a hole on the cover with a punching protrusion to open the cover sealed on a flange more easily. The food and drink packing vessel includes a body(2) having a flange(4) on the upper part thereof and a film shaped cover(3). The cover(3) is heated and sealed on the flange(4) of the body(2) to prevent the food received at inside of the body from being poured out. One or more protruded parts(5) are formed to protrude from the flange(5) to the outside and are covered with the cover(3). A punching protrusion(6) for punching the cover is provided on the position of the protruded parts(5). The punching protrusion(6) is disposed on the cover adhered to the protruded part(5).
Patent KR-20050074347-A (KR)
Inventor: KANG HEE JUNG
IPC: A63C19/10
Filed: 2005-05-20
Abstract: 경사면을 이용한 전천후 건식 스키 구조물이 개시된다. 자연설과 유사한 재질 및 느낌을 주는 모래 혹은 인공재료 (140)를 이용하며; 상기 모래 혹은 인공재료를 경사면 상부로부터 연속하여 흘려 내리는 장치와(150); 경사면의 중간 혹은 종단점 에서 모아진 모래를 수거하는 장치와 (160); 수거된 모래 혹은 인공재료를 다시 경사면의 상부로 이송하는 장치와 (170); 상기 건조된 모래 혹은 인공재료가 강우 혹은 강설 등으로부터 젖지 않도록 방지하기 위한 지붕과 (120); 바람 등으로 인해 재료가 날리는 것을 막기 위한 방풍벽 (130) 으로 구성된다.
Patent KR-20060122212-A (KR)
Title: A system for offering contents and related membership-service and a method thereof
Inventor: GO SANG SUN
IPC: H04W4/12
Filed: 2005-05-25
Abstract: A system and a method for providing contents and supplementary services are provided to enable a contents sender to supply the supplementary service of a certain period for use of the contents even when a contents receiver does not subscribe for the supplementary service in transmitting corresponding contents, thereby providing the contents regardless of whether the receiver has subscribed to the supplementary service. A system for providing contents and supplementary services comprises the followings: a terminal(10) of a sender; wire/wireless terminals(20) of a receiver; an interface server(30); a subscriber information server(40) which stores and manages information about whether the wire/wireless terminal(20) of the receiver has subscribed for the supplementary service; a subscriber information control server(50) which is interworked between the interface server(30) and the subscriber information server(40) and controls supplementary service subscriber information which will be stored in the subscriber information server(40); and a message transmitting server(60) which transmits a predetermined message to the terminal(10) of the sender or the wire/wireless terminal(20) of the receiver when contents provision from the terminal(10) of the sender to the wire/wireless(20) terminal of the receiver is completed.
Patent KR-20060122441-A (KR)
Title: Apparatus and method for editing background picture in video communication device, and personalized background picture transfering service using the same
Inventor: LIM YOUNG SOOK
IPC: H04B1/40
Filed: 2005-05-27
Abstract: An apparatus and a method for editing background images in a video communication terminal, and a personalized background image changing service system using the same are provided to perform user authentication for an originating call and an incoming call, to compose a background image corresponding to the authenticated user and a personal image of an actual user, and to transmit the composed image to a terminal of the other party, thereby protecting user's privacy when a user originates/receives a call by using the video communication terminal. A data input unit(106) receives authentication information about a user, and inputs/outputs a series of data for a call. A user authentication unit(101) performs user authentication for an originating call and an incoming call. An image extracting unit(102) extracts personal information in a user's image photographed through a camera. A memory device stores information for the user authentication and information for providing background image contents according to different individuals. An image management unit(104) extracts background image contents, which a user previously registers, from the memory device. A video/voice communication unit composes the background image contents extracted from the image management unit(104) and the personal information and transmits the composed information to a video communication terminal party of the other party.
Patent KR-20060124490-A (KR)
Title: Battery for mobile communication unit and manufacturing method thereof
Inventor: KIM SANG HWAN
IPC: H01M2/34
Filed: 2005-05-31
Abstract: Provided is a battery for a mobile communication terminal, and its preparation method, to allow the final manufacturing process of a battery to be carried out more conveniently, thereby improving the efficiency and workability of process. The battery comprises a battery cell; a circuit board(200) where a circuit for the control of the electric power applied to the battery cell is formed; an internal connection terminal(220) which is installed at the one side of the circuit board and is connected with the battery cell; and an external connection terminal(230) which is installed at the other side of the circuit board and is combined with the circuit board before combined with the battery cell. Preferably the external connection terminal is made of additional conductive metal material and is combined with the circuit board by melt welding or soldering.
Patent KR-20060049201-A (KR)
Inventor: SATO YOSHIHISA
IPC: G03B21/20
Filed: 2005-06-13
Abstract: 편광 분리 특성이 좋은 편광 빔 분할기를 제공하는 것이다. 
     기둥 모양체의 측면으로서 광의 입사면 또는 출사면으로 이루어지는 제 1 및 제 2의 단면과, 대향면을 가지는 제 1 및 제 2의 유리 프리즘과, 유리 기판의 한쪽 면에 금속 격자가 형성되어 이루어지는 와이어 그리드 편광 분리 소자를 가지고, 와이어 그리드 편광 분리 소자는 금속 격자가 형성되어 있지 않은 쪽의 면이, 제 1의 유리 프리즘의 대향면에 고착된다.    그리고, 제 2의 유리 프리즘은 그 대향면이 공기층을 형성하는 상태로, 와이어 그리드 편광 분리 소자가 고착된 제 1의 유리 프리즘의 상기 대향면에 대향하여 배치되도록 한다.    즉, 금속 격자측은 제 2의 유리 프리즘 측에 접촉하지 않게 된다.
Patent KR-20060130986-A (KR)
Title: Method for manufacturing artificial photo-synthetic solar cell for education
Inventor: LEE DONG YOON
IPC: H01L31/0224
Filed: 2005-06-14
Abstract: A structure for an artificial photo-synthetic solar cell for education and a method of manufacturing the same are provided to form TiO2 nano-porous film by using TiO2 photocatalytic nano-slurry. An artificial photo-synthetic solar cell includes an upper transparent substrate, a conductive transparent electrode(103) formed on an inner surface of the upper transparent substrate, a TiO2 porous cathode formed on the conductive transparent electrode and absorbed with dye on its surface, a relative electrode(106) formed on a lower transparent substrate, and an electrolyte(105) filled between the cathode and the relative electrode. The TiO2 electrode is sintered by using alcohol lamp.
Patent KR-20060130337-A (KR)
Title: Manufacturing apparatus for copper of high purity
Inventor: CHOI YOON JIN
IPC: C22B15/14
Filed: 2005-06-14
Abstract: An apparatus of producing high purity refined copper that remarkably improves purity and production efficiency of regenerated copper by completely removing impurities contained in substituted copper and automating and continuing the neutralization process and the water removal process is provided. An apparatus of producing high purity refined copper comprises: a refining equipment comprising a first injection screw conveyor(120) which is in communication with a dilution water injection port(170) to transfer the acidic substituted copper by receiving acidic substituted copper from a hopper(110) in which dilution water is mixed with acidic substituted copper(C), a recovery screw conveyor(130) which receives an end of the first injection screw conveyor within a screw shaft such that injection holes(131) are perforated on an outer circumferential surface of the screw shaft adjacent to the end, and a first rotary cylinder(140) which receives the recovery screw conveyor and has impurity discharge holes(141) perforated on a portion thereof adjacent to one end face of the screw shaft and substituted copper discharge holes(142) perforated on an outer circumferential surface of the other end thereof; and a neutralizing and water separating equipment comprising a second injection screw conveyor which is in communication with an alkaline water injection port to transfer the substituted copper by receiving substituted copper from a hopper in which alkaline water is mixed with substituted copper from which impurities are removed by the refining equipment, and a second rotary cylinder which receives an end of the second injection screw conveyor, and has a storage space formed along an inner circumferential surface thereof such that refined copper is placed on the storage space and a reticular filter fabric installed on the bottom of the storage space.
Patent KR-20060130428-A (KR)
Title: Apparatus and method for controling charging current of charging machine
Inventor: LEE JAE HYONG
IPC: H02J7/04
Filed: 2005-06-14
Abstract: An apparatus and a method for controlling a charging current of charging machine are provided to shorten total charging time by supplying a bigger charging current to a battery according to a battery temperature. In an apparatus for controlling a charging current of a charging machine, a temperature sensor(21) measures a temperature of a battery(25). A control unit(23) generates a current control signal by determining a variation of the battery temperature measured by the temperature sensor(21). A charging circuit(24) adjusts the charging current upward and downward according to the current control signal and supplies the adjusted current to the battery(25).
Patent KR-20070002916-A (KR)
Title: Backlight unit and method for controlling temperature the same
Inventor: LEE KYU TAE
IPC: G02F1/13357
Filed: 2005-06-30
Abstract: A backlight unit and a temperature control method thereof are provided to smoothly control heat release or heat absorption at a high or low temperature by constructing a cover bottom divided into first to third portions to form a closed curve, and applying a current to the first portion which is adjacent to a lamp and the second portion which is not adjacent to the lamp, controlling a direction of the current. A cover bottom(40) is divided into first to third portions of a portion adjacent to a lamp(41), a portion which is not adjacent to the lamp, and a connection portion therebetween according to a lamp location and forms a closed curve. A current direction controller(43) is connected to the first and second portions of the cover bottom and controls a supply direction of the current in due consideration of a Thompson coefficient of the cover bottom.
Patent KR-20070017616-A (KR)
IPC: H01Q11/08
Filed: 2005-08-08
Abstract: 본 발명은 다중 안테나 구조에 관한 것으로, 그 구성은 다수개의 윈도우에 대해 각각 위치하고, 상기 윈도우에 대해 직교하는 다수개의 고주파 안테나와 진공챔버 내부에 유입되는 플라즈마 가스를 이용하여 피처리 기판상에 소정의 공정을 실행하는 플라즈마 처리장치에 있어서, 상기 고주파 안테나는 상기 하나의 윈도우 상부에 적어도 하나 이상이 위치되도록 하는 다중 안테나 구조에 관한 것이다. 
     본 발명은 다중 안테나가 각각 다른 극성을 갖도록 구성함으로써, 윈도우를 지지하는 프레임에 맴돌이 전류가 발생되는 것을 방지할 수 있는 효과가 있다. 
       
     	다중 안테나, 플라즈마 처리장치
Patent KR-20050088274-A (KR)
Inventor: LIM MYUNG GU
IPC: E04F15/024
Filed: 2005-08-15
Abstract: 본 발명은 기존의 화장실 바닥 위에 또 하나의 바닥을 두어 화장실 바닥을 복층으로 하고 그 상층 바닥판의 높이를 조절하여 상기 상층 바닥판에 올라선 키 작은 유아 또는 어린이들이 안전하고 편리하게 화장실을 이용할 수 있도록 한 상층 바닥판 높낮이 조절이 가능한 복층 구조의 화장실 바닥에 관한 것이다.
Patent KR-20070021624-A (KR)
IPC: H04Q7/38
Filed: 2005-08-19
Abstract: 본 발명은 멀티미디어 링백톤 서비스를 제공하는 방법 및 이동통신 시스템과 멀티미디어 링백톤 서비스를 위한 이동통신 단말기에 관한 것이다. 
     본 발명은 가입자의 링백톤 서비스 가입 여부를 포함하는 프로파일 정보가 저장되어 있는 홈 위치 등록기(HLR: Home Location Register), 링백톤 음원을 저장하고 있는 음원 제공 서버를 이용하여, 발신 가입자가 착신 가입자에게 전화를 하면 착신 가입자가 음원 제공 서버에 미리 설정해 놓은 링백톤 음원이 발신측 이동통신 단말기로 재생되도록 하는 멀티미디어 링백톤 서비스를 제공하는 방법에 있어서, (a) 발신측 이동통신 단말기가 착신측 이동통신 단말기로 호 연결을 시도하면, 홈 위치 등록기로부터 착신측 이동통신 단말기의 위치 정보, 착신측 이동통신 단말기의 링백톤 서비스 가입 여부 및 발신측 이동통신 단말기에서 지원하는 복수의 멀티미디어 코덱 정보를 수신하는 단계; (b) 착신측 이동통신 단말기가 링백톤 서비스에 가입되어 있으면, 복수의 멀티미디어 코덱 정보를 포함한 ISUP(ISDN User Part) 호 접속 요청 메시지를 음원 제공 서버로 전송하는 단계; (c) 발신측 기지국 제어기로 멀티미디어 코덱의 설정을 요청하여 링백톤 서비스를 위한 라우팅 경로를 활성화시키는 단계; 및 (d) 복수의 멀티미디어 코덱 정보를 이용하여 선택된 링백톤 음원을 음원 제공 서버로부터 수신하여 발신측 이동통신 단말기로 전송하는 단계를 포함하는 것을 특징으로 하는  멀티미디어 링백톤 서비스를 제공하는 방법을 제공한다. 
     본 발명에 의하면, 링백톤 서비스에서 다양한 종류의 멀티미디어 코덱을 활용하여 링백톤 구간 동안에는 고품질의 음악을 위한 멀티미디어 코덱을 동작시키고 음성 통화시에는 EVRC와 같은 음성 코덱을 동작시킬 수 있는 방안을 제시함으로써 높은 품질의 링백톤 서비스를 제공한다는 효과가 있다.  
       
     링백톤, 이동통신 교환국, 멀티미디어 코덱, 보코더, 이동통신 단말기
Patent KR-20070024805-A (KR)
Title: Diffusion equipment for semiconductor memory manufacturing
Inventor: KIM SANG YONG
IPC: H01L21/22
Filed: 2005-08-30
Abstract: Diffusion equipment for fabricating a semiconductor device is provided to easily clean the entire part of a boat by injecting cleaning gas to the boat while being disposed near the boat and moving up and down. A plurality of wafers are stacked in a boat(100). A lift(400) is separated from the boat by an interval. A cleaning unit(200) injects cleaning gas to the boat, connected to the lift and including a unit body, a gas injector(230) and a gas supply part(300). The unit body is connected to the lift. The gas injector is mounted on the unit body. The gas supply part supplies the cleaning gas to the gas injector.
Patent KR-20070025127-A (KR)
Title: Egr path structure of intake manifold for internal combustion engine
Inventor: PARK NAM SEOB
IPC: F02M25/07
Filed: 2005-08-31
Abstract: An EGR path structure of an intake manifold for an internal combustion engine is provided to uniformly mix the air introduced into the intake manifold and the recirculated exhaust gas prior to inflow into an engine cylinder. An EGR path structure of an intake manifold(2) for an internal combustion engine is characterized in that a half-cylindrical porous member(10) is disposed in the intake manifold serving as a lower end of an exhaust gas recirculation pipe. The half-cylindrical porous member has a surface with a plurality of holes(8), and is opened inwardly. The half-cylindrical porous member has a cut surface with a front end positioned on a lengthwise central line of the intake manifold, and a top protruded toward an inner wall of the intake manifold.
Patent KR-20070025232-A (KR)
Title: Method for fabricating trench of recess channel in semiconductor device
Inventor: KIM JUNG CHAN
IPC: H01L21/76
Filed: 2005-09-01
Abstract: A method for forming a recess channel trench of a semiconductor device is provided to improve the uniformity of device characteristics, to restrain the generation of leakage current due to junction and to improve refresh characteristics by obtaining a curved portion from the recess channel trench using two-step etching processes. An insulating layer and a hard mask layer are sequentially formed on a semiconductor substrate(200). A photoresist pattern for exposing a predetermined region of the hard mask layer to the outside is formed thereon. A hard mask pattern and an insulating pattern are formed on the resultant structure by an etching process using the photoresist pattern as an etch mask. At this time, the substrate is partially exposed to the outside. A first recess channel trench is formed on the exposed substrate by first etching using the hard mask pattern as an etch mask. An oxide layer is formed along an upper surface of the resultant structure. A sidewall oxide layer is formed at both sides of the first recess channel trench by etching selectively the oxide layer. A second recess channel trench(310) is formed under the first recess channel trench by second etching using the sidewall oxide layer as an etch mask.