Abstract: Silicon substrate etching methods to keep surface unevenness of a structured surface formed by etching to within a fixed value. After an etching mask is formed on its surface, a silicon substrate S is mounted on a base 3 in an etching device 1. An etching gas (SF6) and a protective film forming gas (C4F8) are supplied to a chamber 2. The SF6 gas and the C4F8 gas supplied to the chamber are converted to plasma using a coil 16 to which high-frequency electrical power is applied. For example, by supplying a large amount of SF6 gas while high-frequency electrical power is applied to the base 3, dry etching primarily at the etching ground is advanced. Conversely, by supplying a large amount of C4F8 gas, protective film formation primarily to the etching structured surfaces is advanced. By repeating these steps, deep grooves with smooth structured surfaces can be formed.

Abstract: A method for etching a silicon substrate is presented in which fast etching speed and etching structures with smooth and perpendicular wall surfaces are achieved. In the etching step, a constant electric power is applied to the silicon substrate to provide a bias potential. Using a mixture of SF6 gas and fluorocarbon gas, there is a step mainly for the progression of dry etching of the etching ground surface. Similarly, using a mixture gas, there is a step mainly for forming a protective layer on the structure surfaces which are perpendicular with respect to the etching ground surface. These two steps are repeated one after the other. In the step for dry etching, the mixture gas is 5–12 volume of fluorocarbon gas with respect to 100 volume SF6 gas. The mixture gas in the protective film formation step is a mixture of 2–5 volume of SF6 gas with respect to 100 volume fluorocarbon gas.

Abstract: A cleaning method and an etching method for removing, by cleaning grease components and silicon micro pieces hard to remove, used for an apparatus and a carrier for manufacturing a semiconductor wafer or a semiconductor device. Matters to be removed are brought into contact with XeF2 gas produced by sublimation in a vacuum atmosphere to decompose and gasify the grease components and to remove silicon pieces by etching. If a trace of residual water is left in the vacuum atmosphere before the cleaning, the H2O reacts with XeF2, so that HF is produced. Therefore, for example, the native oxide SiO2 formed on the silicon pieces can be removed, and XeF2 can directly react with silicon, thereby enabling etching. The cleaning and etching speeds are extremely accelerated.

Abstract: A cleaning method for removing fats, oils, and silicon small particles, which are conventionally difficult to remove, adhering to devices and carriers used to manufacture a semiconductor wafer or a semiconductor device. An etching method is also disclosed. XeF2 gas produced by sublimation is made to contact with an object to be cleaned in a vacuum atmosphere so as to decompose and gasify the oils and fats and to remove silicon small particles by etching. Prior to the cleaning, when a trace amount of residual water is left in the vacuum atmosphere, H2O reacts with XeF2, and HF is produced. For example, a native oxide SiO2 formed on the surface of silicon small particles can be removed, and XeF2 directly reacts with silicon, therby enabling etching. The cleaning etching rates are extremely high.

Abstract: A method for etching a silicon substrate is presented in which fast etching speed and etching structures with smooth and perpendicular wall surfaces are achieved. In the etching step, a constant electric power is applied to the silicon substrate to provide a bias potential. Using a mixture of SF6 gas and fluorocarbon gas, there is a step mainly for the progression of dry etching of the etching ground surface. Similarly, using a mixture gas, there is a step mainly for forming a protective layer on the structure surfaces which are perpendicular with respect to the etching ground surface. These two steps are repeated one after the other. In the step for dry etching, the mixture gas is 5-12 volume of fluorocarbon gas with respect to 100 volume SF6 gas. The mixture gas in the protective film formation step is a mixture of 2-5 volume of SF6 gas with respect to 100 volume fluorocarbon gas.

Abstract: A cleaning method for removing fats, oils, and silicon small particles, which are conventionally difficult to remove, adhering to devices and carriers used to manufacture a semiconductor wafer or a semiconductor device. An etching method is also disclosed. XeF2 gas produced by sublimation is made to contact with an object to be cleaned in a vacuum atmosphere so as to decompose and gasify the oils and fats and to remove silicon small particles by etching. Prior to the cleaning, when a trace amount of residual water is left in the vacuum atmosphere, H2O reacts with XeF2, and HF is produced. For example, a native oxide SiO2 formed on the surface of silicon small particles can be removed, and XeF2 directly reacts with silicon, therby enabling etching. The cleaning etching rates are extremely high.

Abstract: The present invention relates to a method and device for etching a silicon substrate that can keep surface unevenness of a structured surface formed by etching to within a fixed value. After an etching mask is formed on its surface, a silicon substrate S is mounted on a base 3 in an etching device 1. An etching gas (SF6) and a protective film forming gas (C4F8) are supplied to a chamber 2. The SF6 gas and the C4F8 gas supplied to the chamber are converted to plasma using a coil 16 to which high-frequency electrical power is applied. For example, by supplying a large amount of SF6 gas while high-frequency electrical power is applied to the base 3, dry etching primarily at the etching grounds is advanced. Conversely, by supplying a large amount of C4F8 gas, protective film formation primarily to the etching structured surfaces is advanced. By repeating these steps, deep grooves with smooth structured surfaces can be formed.

Abstract: A cleaning method and an etching method for removing, by cleaning grease components and silicon micro pieces hard to remove, used for an apparatus and a carrier for manufacturing a semiconductor wafer or a semiconductor device. Matters to be removed are brought into contact with XeF2 gas produced by sublimation in a vacuum atmosphere to decompose and gasify the grease components and to remove silicon pieces by etching. If a trace of residual water is left in the vacuum atmosphere before the cleaning, the H2O reacts with XeF2, so that HF is produced. Therefore, for example, the native oxide SiO2 formed on the silicon pieces can be removed, and XeF2 can directly react with silicon, thereby enabling etching. The cleaning and etching speeds are extremely accelerated.

Abstract: A cleaning method for removing fats, oils, and silicon small particles, which are conventionally difficult to remove, adhering to devices and carriers used to manufacture a semiconductor wafer or a semiconductor device. An etching method is also disclosed. XeF2 gas produced by sublimation is made to contact with an object to be cleaned in a vacuum atmosphere so as to decompose and gasify the oils and fats and to remove silicon small particles by etching. Prior to the cleaning, when a trace amount of residual water is left in the vacuum atmosphere, H2O reacts with XeF2, and HF is produced. For example, a native oxide SiO2 formed on the surface of silicon small particles can be removed, and XeF2 directly reacts with silicon, therby enabling etching. The cleaning etching rates are extremely high.

Abstract: An active matrix liquid crystal display improves its contrast by suppressing irregularity of an alignment film caused by video lines thereby reducing reverse regions on a display electrode. The active matrix liquid crystal display has first and second opposite substrates, a video line, an active element and a display electrode which are directly or indirectly formed on the first substrate, and an alignment film which is formed on or above the video line, the active element and the display electrode. The alignment film is so formed that is surface is at an angle of inclination of not more than 10.5.degree. with respect to the display electrode surface between the video line and the display electrode.

Abstract: An active matrix liquid crystal display improves its contrast by suppressing irregularity of an alignment film caused by video lines thereby reducing reverse regions on a display electrode. The active matrix liquid crystal display has first and second opposite substrates, a video line, an active element and a display electrode which are directly or indirectly formed on the first substrate, and an alignment film which is formed on or above the video line, the active element and the display electrode. The alignment film is so formed that its surface is at an angle of inclination of not more than 10.5.degree. with respect to the display electrode surface between the video line and the display electrode.

Abstract: A liquid crystal display comprising a liquid crystal and a polyimide alignment layer for orienting the liquid crystal, wherein the polyimide alignment layer has a plurality of regions which are at different imidiation ratios, whereby liquid crystal portions corresponding to the respective regions are oriented at different pretilt angles which are responsive to the imidiation ratios.