Abstract: A glass substrate for a magnetic disk of the invention is a disk-shaped glass substrate for a magnetic disk where the substrate has a main surface and end face and is subjected to chemical reinforcement treatment, and is characterized in that the penetration length in the uppermost-portion stress layer on the main surface is 49.1 ?m or less, and that assuming that an angle between the main surface and compressive stress in the stress profile by a Babinet compensator method is ?, a value y of {12·t·ln(tan ?)+(49.1/t)} is the penetration length in the uppermost-portion stress layer or less.

Abstract: An aspect of the present invention relates to a glass substrate for a magnetic recording medium, which is comprised of glass with a glass transition temperature of equal to or greater than 600° C., an average coefficient of linear expansion at 100 to 300° C. of equal to or greater than 70×10?7/° C., a Young's modulus of equal to or greater than 81 GPa, a specific modulus of elasticity of equal to or greater than 30 MNm/kg, and a fracture toughness value of equal to or greater than 0.9 MPa·m1/2.

Abstract: This invention provides a method for manufacturing a glass substrate for a magnetic disk comprising a chemical strengthening step. The method provides a glass substrate for a magnetic disk that can suppress the occurrence of very small waves in cooling a glass substrate after the chemical strengthening step, and, while preventing troubles such as head crush and thermal asperity, can realize lowered flying height of a magnetic head and high-density information recording, and is particularly suitable for application to small-size magnetic disks for portable information equipment. In the step of cooling after the chemical strengthening step, cooling treatment is carried out in which the glass substrate is brought into contact with a treatment liquid containing a melt of a material having a solidification temperature below that of a chemical strengthening salt.

Abstract: The present invention provides a method for producing a glass substrate for a magnetic disk in which the occurrence of micro-waviness on the glass substrate is prevented in a cooling step after a chemically strengthening step so that the glass substrate has a significantly smooth principal surface, and provides a method for producing a magnetic disk in which head crash, thermal asperity failures, and the like are prevented, the flying height of a magnetic head can be decreased, and high-density recording is enabled.

Abstract: An aspect of the present invention relates to a glass substrate for a magnetic recording medium, which is comprised of glass with a glass transition temperature of equal to or greater than 600° C., an average coefficient of linear expansion at 100 to 300° C. of equal to or greater than 70×10?7/° C., a Young's modulus of equal to or greater than 81 GPa, a specific modulus of elasticity of equal to or greater than 30 MNm/kg, and a fracture toughness value of equal to or greater than 0.9 MPa·m1/2.

Abstract: A glass substrate for a magnetic disk of the invention is a disk-shaped glass substrate for a magnetic disk where the substrate has a main surface and end face and is subjected to chemical reinforcement treatment, and is characterized in that the penetration length in the uppermost-portion stress layer on the main surface is 49.1 ?m or less, and that assuming that an angle between the main surface and compressive stress in the stress profile by a Babinet compensator method is ?, a value y of {12·t·ln(tan ?)+(49.1/t)} is the penetration length in the uppermost-portion stress layer or less.

Abstract: A glass substrate for a magnetic disk of the invention is a disk-shaped glass substrate for a magnetic disk where the substrate has a main surface and end face and is subjected to chemical reinforcement treatment, and is characterized in that the penetration length in the uppermost-portion stress layer on the main surface is 49.1 ?m or less, and that assuming that an angle between the main surface and compressive stress in the stress profile by a Babinet compensator method is ?, a value y of {12·t·ln(tan ?)+(49.1/t)} is the penetration length in the uppermost-portion stress layer or less.

Abstract: A glass substrate for a magnetic disk of the invention is a disk-shaped glass substrate for a magnetic disk where the substrate has a main surface and end face and is subjected to chemical reinforcement treatment, and is characterized in that the penetration length in the uppermost-portion stress layer on the main surface is 49.1 ?m or less, and that assuming that an angle between the main surface and compressive stress in the stress profile by a Babinet compensator method is ?, a value y of {12·t·ln(tan ?)+(49.1/t)} is the penetration length in the uppermost-portion stress layer or less.

Abstract: This invention provides a method for manufacturing a glass substrate for a magnetic disk comprising a chemical strengthening step. The method provides a glass substrate for a magnetic disk that can suppress the occurrence of very small waves in cooling a glass substrate after the chemical strengthening step, and, while preventing troubles such as head crush and thermal asperity, can realize lowered flying height of a magnetic head and high-density information recording, and is particularly suitable for application to small-size magnetic disks for portable information equipment. In the step of cooling after the chemical strengthening step, cooling treatment is carried out in which the glass substrate is brought into contact with a treatment liquid containing a melt of a material having a solidification temperature below that of a chemical strengthening salt.

Abstract: The present invention provides a method for producing a glass substrate for a magnetic disk in which the occurrence of micro-waviness on the glass substrate is prevented in a cooling step after a chemically strengthening step so that the glass substrate has a significantly smooth principal surface, and provides a method for producing a magnetic disk in which head crash, thermal asperity failures, and the like are prevented, the flying height of a magnetic head can be decreased, and high-density recording is enabled.

Abstract: A method for manufacturing a magnetic disk glass substrate including a chemical strengthening step is provided. In the method, chemical strengthening treatment is sufficiently performed over the entire main surfaces of a glass substrate. Consequently, the resulting magnetic disk glass substrate can provide a magnetic disk allowing the magnetic head to have a low flying height and achieving high-density information recording, and particularly a magnetic desk suitably used in small hard disk drives for portable information apparatuses. In the chemical strengthening step, a chemical strengthening agent is brought into contact with a glass substrate to perform ion exchange by allowing the chemical strengthening agent to flow with respect to the glass substrate, or by moving the glass substrate with respect to the chemical strengthening agent.

Abstract: A wafer transfer method, by which, when a wafer is loaded into a system, heat shock applied to the wafer can be relieved, the frequency of occurrence of crystal dislocation such as slip can be decreased, and productivity can be improved due to saving of energy and time required for heating and cooling of the system, and there is also provided a wafer support member used for this method. In this method, a step for transferring wafers so as to replace a wafer, which finishes its thin film growth process, with a following wafer, which is to be subjected to its thin film growth process, is carried out under the temperature being higher than the room temperature, while the wafer 1 is transferred integrally with a wafer support member 2 used for the thin film growth process.

Abstract: There is provided a wafer transfer method, by which, when a wafer is loaded into a system, heat shock applied to the wafer can be relieved, the frequency of occurrence of crystal dislocation such as slip can be decreased, and productivity can be improved due to saving of energy and time required for heating and cooling of the system, and there is also provided a wafer support member used for this method. In this method, a step for transferring wafers so as to replace a wafer, which finishes its thin film growth process, with a following wafer, which is to be subjected to its thin film growth process, is carried out under the temperature being higher than the room temperature, while the wafer 1 is transferred integrally with a wafer support member 2 used for the thin film growth process.

Abstract: An apparatus for reduced-pressure gaseous phase epitaxial growth by suppressing contamination upon the machine parts constituting the rotary mechanical portion and suppressing contamination upon the semiconductor wafer by maintaining the pressure in the rotary mechanical portion to lie within a particular range, and a method of controlling the above apparatus.

Abstract: A method of controlling the temperature of a semiconductor substrate for prevention of any cracks from being formed in the semiconductor substrate event though semiconductors having different temperature rise/fall characteristics are fed into a reactor in which each semiconductor substrates is subjected to an oxidation, diffusion, or a chemical vapor deposition process. The temperatures are measured at various points in the semiconductor substrates in the heated reactor; the temperature rise/fall characteristic thereof is determined by computing the rate of temperature rise and the in-plane temperature distribution out of the measured values; a temperature control program adaptable for said temperature rise/fall characteristic is automatically selected out of a plurality of temperature control programs written in advance; the semiconductor substrate is controlled on the basis of the selected temperature control program.

Abstract: An improved method of growing a thin film in gaseous phase maintaining a uniform thickness and uniform electric properties such as resistivity, etc. over the whole surface of the film, and an apparatus for growing a thin film in gaseous phase adapted to conducting the above method.

Abstract: An apparatus for reduced-pressure gaseous phase epitaxial growth by suppressing contamination upon the machine parts constituting the rotary mechanical portion and suppressing contamination upon the semiconductor wafer by maintaining the pressure in the rotary mechanical portion to lie within a particular range, and a method of controlling the above apparatus.

Abstract: A method of controlling the temperature of a semiconductor substrate for prevention of any cracks from being formed in the semiconductor substrate event though semiconductors having different temperature rise/fall characteristics are fed into a reactor in which each semiconductor substrates is subjected to an oxidation, diffusion, or a chemical vapor deposition process. The temperatures are measured at various points in the semiconductor substrates in the heated reactor; the temperature rise/fall characteristic thereof is determined by computing the rate of temperature rise and the in-plane temperature distribution out of the measured values; a temperature control program adaptable for said temperature rise/fall characteristic is automatically selected out of a plurality of temperature control programs written in advance; the semiconductor substrate is controlled on the basis of the selected temperature control program.

Abstract: The present invention provides a wafer heating device which can improve uniformity of a temperature distribution within a surface area of a wafer, with a relatively simple structure. A wafer is supported on a susceptor of annular shape. A first heater of disc shape is disposed below the wafer, and a second heater of annular shape is disposed to surround the first heater. Radiation thermometers are arranged at a ceiling portion of a reaction chamber. The first radiation thermometer measures a temperature of a central area of the wafer, the second radiation thermometer measures a temperature of a peripheral area of the wafer, and the third radiation thermometer measures a temperature of the susceptor. The first heater and the second heater are controlled by independent closed loops. When a wafer is set on the susceptor, a power of the second heater is controlled by using a value measured by the second radiation thermometer as a feedback signal.

Abstract: A vapor deposition apparatus for supplying raw-material gas into a reactor to form a thin film on a wafer substrate disposed in the reactor by vapor deposition, including at least a rotator for mounting the wafer substrate thereon, a treatment gas introducing port, a straightening vane having plural holes, and a wafer substrate feed-in/out port, wherein the lowermost portion of the wafer feed-in/out port is located at a predetermined height from the upper surface of the rotator, and the difference in height between the lowermost portion of the wafer feed-in/out port and the upper surface of the rotator is set to be larger than the thickness of a transition layer of the upper portion of the rotator. In a vapor deposition method, a wafer substrate is mounted on the rotator to form a thin film having little defect and uniform film thickness on the wafer substrate by using the vapor deposition apparatus.