Lanthanide oxide dissolution from glass surface
AssigneeInternational Business Machines Corporation
InventorDouglas Howard Piltingsrud
Life of this patent
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Abstract
A method and product for computer disk drives. Glass substrates are provided having low content of residual polishing particles on the surfaces thereof. An exemplary method includes reduction of residual polishing particle content by immersion of the glass substrate in an acid bath containing nitric acid, hydrogen peroxide and an organic acid having a carboxylic acid group.
Claims9
A method for manufacturing a disk, comprising the steps of:
- polishing a glass substrate with a slurry comprising lanthanide oxide particles;
- and
- cleaning the polished glass substrate having lanthanide oxide particles thereon to remove said lanthanide oxide particles, said cleaning step leaving no more than about 1.52×10−4 ng/mm2 of each type of lanthanide oxide on said glass substrate.
A glass substrate having a polished surface comprising less than about 1.52×10−4 ng/mm2 each of oxide particles of lanthanide series elements selected from the group consisting of:
- lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
A glass substrate having a polished surface comprising less than about 1.52×10−4 ng/mm2 each of oxide particles of lanthanide series elements selected from the group consisting of:
- lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, said substrate produced by the method of:
- (a) polishing a glass substrate with a slurry comprising oxide particles of lanthanide series elements;
- (b) ultrasonically cleaning the polished glass substrate;
- (c) mechanically scrubbing the polished glass substrate with soap and a pad;
- (d) immersing the polished glass substrate in an acid bath comprising nitric acid, hydrogen peroxide and an organic acid having a carboxylic acid group;
- (e) scrubbing the polished glass substrate with polyvinyl alcohol pads and potassium hydroxide;
- and
- (f) immersing the polished glass substrate in a basic bath of potassium hydroxide, wherein the step of immersion in the acid bath substantially dissolves the lanthanide series oxide particles from the polished glass substrate into the acid bath thereby reducing the content of the lanthanide series oxide particles present on the polished surface.
A glass substrate having a polished surface comprising less than about 1.52×10−4 ng/mm2 each of oxide particles of lanthanide series elements selected from the group consisting of:
- lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, said substrate produced by the method of:
- (a) polishing a glass substrate with a slurry comprising oxide particles of lanthanide series elements;
- (b) ultrasonically cleaning the polished glass substrate;
- (c) mechanically scrubbing the polished glass substrate with soap and a pad;
- (d) immersing the polished glass substrate in an acid bath comprising nitric acid, hydrogen peroxide and an organic acid having a carboxylic acid group;
- (e) scrubbing the polished glass substrate with polyvinyl alcohol pads and potassium hydroxide;
- (f) immersing the polished glass substrate in a basic bath of potassium hydroxide;
- (g) subjecting the polished glass substrate to chemical strengthening;
- (h) immersing the polished glass substrate in an etching bath of a surfactant and an acid selected from the group consisting of organic acids and sulfuric acid;
- (i) repeating step (e);
- and
- (j) repeating step (f), wherein the step of immersion in the acid bath substantially dissolves the lanthanide series oxide particles from the polished glass substrate into the acid bath thereby reducing the content of the lanthanide series oxide particles present on the polished surface.
A disk drive product comprising a glass substrate having a polished surface comprising less than about 1.52×10−4 ng/mm2 each of oxide particles of lanthanide series elements selected from the group consisting of:
- lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
Dependencies are inferred from the claim text.