Siemens Aktiengesellschaft

Manfred Wintzer

Klaus Burkart

Christian Stein

Karl Niedermeier

Michael Mazzuchelli

Two parts, such as a quartz part and piezo-electric part, are indirectly connected to one another by applying relatively thin metallic layers having a thickness of about 0.5 nm to 55 nm under vacuum conditions onto the surfaces of such parts to be joined and then without ventilation of the vacuum-chamber contacting the free surfaces of such metallic layers with one another under the maintained vacuum conditions whereby a substantially permanent bond is formed between such layer.

Method of indirectly connecting two parts

A method of indirectly connecting two parts, such as an acousto-optical building component composed of lead glass and a piezo electric transducer composed of lead-zirconium titanate, whereby at least one mono-molecular layer (having a maximum thickness of 100 nm) composed of a lead-free glass is directly applied under vacuum onto the surfaces of the parts to be joined and metal layers are then applied under vacuuum onto such glass layer and/or the surfaces to be joined so that when the free surfaces of such free metal layers are brought into contact with one another under vacuum, a bond forms therebetween and such bonds indirectly connect the parts with one another. The glass layer prevents diffusion of atoms or ions from the materials (such as lead) on either side of such layer so that the parts so-joined and/or the bonds so-formed are not impaired in any way.

A substantially homogeneous ceramic mass comprised of about 48 to 88 wt. % of alumina; about 4 to 12 wt. % of polyvinyl butyral; about 0.5 to 5 wt. % of polypropylene oxide - ethylene oxide block polymer; about 3 to 10 wt. % of a polymer solution comprised of acrylic acid esters, methacrylic acid esters and mixed polymers thereof; about 3 to 10 wt. % of a polyvalent alcohol and mixtures of such alcohols; about 1 to 5 wt. % of triethylene glycol and about 0.5 to 10 wt. % of water is produced and vacuum-extruded into an endless relatively flat strip, dried to a green state, shaped into a desired substrate shape and, if to be used with thin layer circuits, subjected to a plane-parallel pressure of about 9,000 to 12,000 N/cm.sup.2 and then fired or sintered into rigid ceramic substrates.

Process for producing ceramic substrates for electronic circuits

A process for the production of ceramic substrates for thin layer circuits utilizes a cast compound which may be transformed into a ceramic body by sintering. The compound is poured out in the form of a coating on a base, for drying whereupon a leather-like, tough, 'green' substrate layer is formed from which the required shapes can be punched out and sintered. In the green, air-drying state, the substrates are exposed to a pressure of up to approximately 1000 kp/cm.sup.2 between highly polished, plane parallel surfaces constituted by mirror finished surfaces of compression rams which may advantageously include highly polished surfaces of synthetic material.

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Unterpfaffenhofen, Germany

Manfred Wintzer