US 5,632,942 AGranted

Method for preparing multilayer ceramic/glass substrates with electromagnetic shielding

AssigneeIndustrial Technoology Research Institute

InventorsTsung-Shou Yeh, Shiang-Po Hwang, Chien-Min Wang, Chung-Yu Ting

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Abstract

A method for making multilayer ceramic/glass substrates with electromagnetic shielding. The method comprises the steps of: (a) preparing a homogeneous inorganic slurry composition by blending and milling a mixture containing ceramic or glass powders, or mixture thereof, an aqueous or organic solvent, a polymeric binder resin, a plasticizer, and other appropriate additives; (b) preparing a plurality of precursory ceramic/glass matrixes from the slurry using a tape casting, extrusion, coating, or pressing technique; (c) cutting the precursory ceramic/glass matrixes into a desired shape and size; (d) applying a conductive metal coating layer on at least one precursory ceramic/glass matrix to form a metal-coated precursory ceramic/glass matrix; (e) stacking an uncoated said precursory ceramic/glass matrix on top of at least one metal-coated precursory matrix to form a stacked multilayer precursory substrate; (f) laminating and sintering the stacked multilayer precursory substrate to form a sintered and densified ceramic/glass substrate. Finally the ceramic/glass substrate is trimmed and polished the desired size, shape, flatness and roughness. In a preferred embodiment, the substrate contains two metal coating layers embedded in a three-matrix structure, each of the metal coating layer has a checker-board coated/uncoated pattern allowing the ceramic/glass matrixes in adjacent layers to grow into and connect each other while providing complete areal coverage to adequately protect the substrate from electromagnetic interference.

A method for preparing multilayer ceramic or glass substrates with electromagnetic shielding for use in making computer hard discs, said method comprising the steps

(a) preparing a slurry composition comprising at least one member selected from the group consisting of ceramic powders and glass powders, an aqueous or organic solvent, a polymeric binder resin, and a plasticizer;
(b) blending and milling said slurry composition to form a homogeneous slurry;
(c) preparing a plurality of precursory ceramic or glass matrixes from said slurry;
(d) cutting each of said precursory ceramic or glass matrixes into a predetermined shape and size;
(e) applying a conductive metal coating layer on at least two of said precursory ceramic or glass matrixes to form at least two metal-coated precursory ceramic or glass matrix, each of said metal coating layers having a predetermined coated/uncoated pattern such that collectively said at least two of said metal coating layers are capable of providing a ubiquitous areal coverage for said substrate;
(f) stacking at least an uncoated said precursory ceramic or glass matrix and said at least two of said metal-coated precursory matrixes together in a head-to-tail manner to form a stacked multilayer precursory substrate, wherein said metal-coated matrixes are arranged in such a manner that the metal-coated portions thereof collectively provide a ubiquitous areal shield to protect said ceramic/glass matrix against magnetic interference;
(g) laminating said stacked multilayer precursory substrate under a predetermined temperature and pressure to form a laminated precursory substrate;
(h) sintering said laminated precursory substrates in a furnace to form a sintered substrate, wherein said sintering procedure causing said ceramic matrixes to grow through said uncoated portions of said metal-coated matrixes and into each other so as to allow said metal coating layers to be firmly laminated with the ceramic or glass layers to form an integrated ceramic or glass substrate with magnetic shield;
and
(i) trimming and polishing said sintered substrate to obtain a predetermined size, shape, flatness and roughness.

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Abstract

Claims20