1. A method for producing a glass substrate for a magnetic disk comprising:
a glass substrate polishing step;
a chemically strengthening step in which a glass substrate is immersed in a chemically strengthening salt solution prepared by dissolving a chemically strengthening salt under heating, and metal ions in the glass substrate are ion-exchanged with metal ions in the chemically strengthening salt; and
a cooling step of cooling the glass substrate after the chemically strengthening step,
wherein the chemically strengthening step is carried out using the chemically strengthening salt solution comprising KNO3 and NaNO3 as a main component of the chemically strengthening salt and an additive component other than the chemically strengthening salt, which is added in an amount of 6% by weight or more in the chemically strengthening salt solution so that the chemically strengthening salt solution does not start to solidify until a temperature decreases to a predetermined temperature at which a surface shape of the glass substrate is not deformed by a force applied to the glass substrate when the chemically strengthening salt having adhered onto the glass substrate after the chemically strengthening step solidifies in the cooling step,
whereby, as a result of said steps, a maximum value of micro-waviness on a principal surface of the glass substrate is made to be less than 5 nm when waviness is measured having a frequency with a wavelength of 4 \u03bcm to 1 mm and is measured in a rectangular measurement area with sides of 800 \u03bcm and 980 \u03bcm of the principal surface of the glass substrate.
2. The method for producing a glass substrate for a magnetic disk according to claim 1, wherein the additive component is at least one selected from the group consisting of Ca(NO3)2, Ca(NO3)2.4H2O, Ni(NO3)2, Ni(NO3)2.6H2O, Mn(NO3)2, Mn(NO3)2.6H2O, Co(NO3)2, Cu(NO3)2, Cu(NO3)2.3H2O, LiNO3, Mg(NO3)2, Mg(NO3)2.6H2O, NaNO2, KNO2, Na2SO4, and K2SO4.
3. The method for producing a glass substrate for a magnetic disk according to claim 1, wherein a material for the glass substrate is an aluminosilicate glass.
4. The method for producing a glass substrate for a magnetic disk according to claim 3, wherein the material for the glass substrate contains, as main components, 58% to 75% by weight of SiO2, 5% to 23% by weight of Al2O3, 3% to 10% by weight of Li2O, and 4% to 13% by weight of Na2O.
5. A method for producing a magnetic disk comprising forming at least a magnetic layer on a surface of a glass substrate obtained by the method for producing a glass substrate for a magnetic disk according to claim 1.
6. The method for producing a magnetic disk according to claim 5, wherein the method is applied to a magnetic disk for a hard disk drive in which a flying height of a magnetic head is 6 nm or less.
7. The method for producing a glass substrate for a magnetic disk according to claim 1, wherein the polishing step is conducted prior to the chemically strengthening step.
8. The method for producing a glass substrate for a magnetic disk according to claim 1, wherein the polishing step is conducted after the chemically strengthening step.
9. A method for producing a glass substrate for a magnetic disk comprising:
a chemically strengthening step in which a glass substrate is brought into contact with a heated chemically strengthening salt solution to strengthen a surface layer of the glass substrate; and
a polishing step for a principle surface of said glass substrate,
wherein the chemically strengthening step is carried out using a chemically strengthening salt solution comprising KNO3 and NaNO3 as a main component of a chemically strengthening salt and an additive component other than the chemically strengthening salt, which is added in an amount of 6% by weight or more in the chemically strengthening salt solution such that a temperature at which the chemically strengthening salt contained in the chemically strengthening salt solution starts to solidify is a predetermined temperature or lower,
whereby, as a result of the chemically strengthening and polishing steps, a maximum value of micro-waviness on a principal surface of the glass substrate is made to be less than 5 nm when waviness is measured having a frequency with a wavelength of 4 \u03bcm to 1 mm and is measured in a rectangular measurement area with sides of 800 \u03bcm and 980 \u03bcm of the principal surface of the glass substrate.
10. The method for producing a glass substrate for a magnetic disk according to claim 9, wherein the additive component is at least one selected from the group consisting of Ca(NO3)2, Ca(NO3)2.4H2O, Ni(NO3)2, Ni(NO3)2.6H2O, Mn(NO3)2, Mn(NO3)2.6H2O, Co(NO3)2, Cu(NO3)2, Cu(NO3)2.3H2O, LiNO3, Mg(NO3)2, Mg(NO3)2.6H2O, NaNO2, KNO2, Na2SO4, and K2SO4.
11. The method for producing a glass substrate for a magnetic disk according to claim 9, wherein the polishing step is conducted prior to the chemically strengthening step.
12. The method for producing a glass substrate for a magnetic disk according to claim 9, wherein the polishing step is conducted after the chemically strengthening step.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A cluster type semiconductor processing apparatus comprising:
a wafer handling chamber having a polygonal base including multiple sides for wafer processing chambers and two adjacent sides for wafer loadingunloading chambers as viewed in a direction of an axis of the wafer handling chamber, said multiple sides optionally including a blank side for maintenance,
wherein each of the multiple sides for wafer processing chambers and the two adjacent sides for wafer loadingunloading chambers is arranged perpendicular to a line passing through the axis of the wafer handling chamber and a center of each side as viewed in the axial direction of the wafer handling chamber,
two adjacent sides of the multiple sides for wafer processing chambers form an angle A measured between a line passing through the axis of the wafer handling chamber and the center of one of the two adjacent sides for wafer processing chambers and a line passing through the axis of the wafer handling chamber and the center of the other of the two adjacent sides for wafer processing chambers, wherein the angle A is greater than an angle B which is calculated by dividing 360\xb0 by the number of the total sides consisting of the multiple sides for wafer processing chambers and the two adjacent sides for wafer loadingunloading chambers,
a distance from the axis of the wafer handling chamber to each of the two adjacent sides for wafer loadingunloading chambers is greater than a distance from the axis of the wafer handling chamber to each of the multiple sides for wafer processing chambers.
2. The cluster type semiconductor processing apparatus according to claim 1, wherein the two adjacent sides for wafer loadingunloading chambers form an angle C measured between a line passing through the axis of the wafer handling chamber and the center of one of the two adjacent sides for wafer loadingunloading chambers and a line passing through the axis of the wafer handling chamber and the center of the other of the two adjacent sides for wafer loadingunloading chambers, wherein the angle C is smaller than the angle B.
3. The cluster type semiconductor processing apparatus according to claim 1, wherein the number of the total sides is seven.
4. The cluster type semiconductor processing apparatus according to claim 1, wherein the multiple sides for wafer processing chambers include one blank side for maintenance.
5. The cluster type semiconductor processing apparatus according to claim 3, wherein the multiple sides for wafer processing chambers include one blank side for maintenance which is located opposite the two adjacent sides for wafer loadingunloading chambers with reference to the axis of the wafer handling chamber.
6. The cluster type semiconductor processing apparatus according to claim 3, wherein a distance W between an edge of the side for a wafer processing chamber next to one of the two adjacent sides for wafer loadingunloading chambers and an edge of the side for a wafer processing chamber next to the other of the two adjacent sides for wafer loadingunloading chambers is substantially or nearly the same as a length of the side for a wafer processing chamber located opposite the two adjacent sides for wafer loadingunloading chambers with reference to the axis of the wafer handling chamber.
7. The cluster type semiconductor processing apparatus according to claim 6, wherein the distance W is greater than a length of each side for a wafer processing chamber except for the side located opposite the two adjacent sides for wafer loadingunloading chambers.
8. The cluster type semiconductor processing apparatus according to claim 6, wherein the side for a wafer processing chamber located opposite the two adjacent sides for wafer loadingunloading chambers is a blank side for maintenance.
9. The cluster type semiconductor processing apparatus according to claim 1, further comprising wafer processing chambers connected to the respective sides for wafer processing chambers except for one blank side for maintenance.
10. The cluster type semiconductor processing apparatus according to claim 1, further comprising wafer loadingunloading chambers connected to the respective sides for wafer loadingunloading chambers.
11. The cluster type semiconductor processing apparatus according to claim 9, wherein the blank side for maintenance is located opposite the two adjacent sides for wafer loadingunloading chambers, wherein outermost portions of the wafer processing chambers disposed between the blank side and the two adjacent sides for wafer loadingunloading chambers are aligned in a line as viewed in the axial direction of the wafer handling chamber, said line being parallel to a line passing through the axis of the wafer handling chamber and between the two adjacent sides for wafer loadingunloading chambers.
12. The cluster type semiconductor processing apparatus according to claim 9, wherein at least one of the wafer processing chambers is a plasma CVD reactor.
13. The cluster type semiconductor processing apparatus according to claim 10, wherein the wafer loadingunloading chambers are load lock chambers.