International Business Machines Corporation

Werner Steiner

Gerhard Trippel

Johann Greschner

Gerhard E Schmid

Holger Hinkel

Olaf Wolter

Arwed Brunsch

Upali Bandara

Thomas Bayer

Klaus Meissner

Roland R Stoehr

Gerhard Elsner

Werner Zapka

Volker Heinrich

Artur Lang

Erwin Prinz

The invention relates to a contact probe arrangement for electrically connecting a test system with contact pads of a device to be tested. The contact probes are located in guide grooves. The guide grooves as well as areas are provided in a plane parallel to the surface of a guide plate and are covered by a protective plate. The contact probes may bend out laterally into the respective areas. This assures a very dense contact probe array. Contact probe arrays of this type may be used, for example, for detecting opens and shorts in integrated circuits or semiconductor chips. The invention overcomes the problem of adjusting for height differences in the contact pads caused by an uneven surface of the device to be tested.

Contact probe arrangement

Grooved substrates and multilayer structures, especially suitable for optical disks, are taught. The major process steps include spin coating of a supporting plate with dissolved material forming a soft layer thereon, stamping grooves into the soft layer to form a structured soft layer showing the negative image of the stamp and hardening the structured soft layer by thermal treatment. The dissolved material contains polymeric organometal compounds comprising polymer siloxane and/or polymer silicates. In one embodiment the structured soft layer is a dielectric layer containing various combinations of the oxides SiO.sub.2, La.sub.2 O.sub.3, PbO and TiO.sub.2. The multilayer structure completed by a magneto-optic layer, a reflector layer and a passivation layer.

Manufacturing process for grooved substrates and multilayer structure

An optical storage disk consists of a glass substrate (1) into which guide tracks (3) for servo-controlling the focussed light beams are directly stamped by a hot stamp process. After stamping, the glass substrate is thermally quenched in the stamping device to increase its breaking resistance through thermal curing. In order to achieve uniform guide tracks over the entire surface of an optical storage disk, flexible stamp stencils (35) in a flexible holder (34) are used whose curvature can be changed by applying hydro-static pressure. Suitable stamp stencils consist of monocristalline silicon disks with surface hardening, or of metal disks, structured in photolithographic processes. The stamp lands are made with bevelled edges to facilitate the separating of stamp and glass substrate after cooling.

System for stamping an optical storage disk

Method of manufacturing an optical Storage disk

A method and apparatus is provided for characterizing magnetic coating compositions that contain magnetic particles dispersed in a solvent resin matrix. The coating composition, as it passes through a tube, is subjected to an alternating magnetic field and perpendicular thereto a constant magnetic field of appropriate field strength and duration. Via a measuring coil surrounding the tube the induced signal in the composition is monitored and the degree of dispersion, is measured by measuring the magnetic susceptibility of the coating material. By applying a constant magnetic field the degree of dispersion cna be changed at least for a certain time. The method and apparatus of the present invention can be incorporated into a coating apparatus to monitor and improve the magnetic characteristics of the coating material being applied to a substrate.

Method and apparatus for characterizing magnetic coating compositions as

Method for measuring the properties of a slider/disk interface in a magnetic disk storage apparatus by measuring a triboelectric current flowing between disk and slider. Rotational speed is adjusted between 100 and 500 rpm so as to obtain a frictional contact between disk and slider. The shape of the tribo current curve obtained during the measuring time interval is analyzed. An early maximum of the tribo current amplitude and a subsequent continual decay indicates a good slider/disk interface and a long lifetime.

System for testing magnetic head/disk interfaces

The magnetic disk contains on a disk substrate a magnetic layer comprising a binder, magnetic particles and abrasion-resistant particles, the abrasion-resistant particles being enveloped with a layer intensifying the bond between binder and abrasion-resistant particles. The enveloping layer either has a large specific surface and consists e.g. of SiO.sub.2 /Al.sub.2 O.sub.3 produced by processing the particles with an alkali metal silicate solution and an aluminum sulphate solution, or it is chemically bonded to the binder by enveloping the particles with poly(tetrafluroethylene) and coupling the latter, via an amino bridge to the binder, e.g. an epoxide resin.

Magnetic disk and method of making same

For characterizing coating compositions with magnetic particles the coating composition is subjected to an alternating magnetic field of variable frequency. The field induced by the coating composition after energization is recorded, and thus the susceptibility of the coating composition is measured. Depending on the variable frequency, conclusions can be made regarding the degree of dispersion, particle density, and viscosity of the coating composition. The variable frequency is between 1 and 100 cps, and the field intensity of the energizing field should be lower than 10 Oerstedt. The coating composition is fluid or stagnant in a pipe *1, 11 which is surrounded by field coil and measuring coil.

Method of determining dispersion, particle density or viscosity of

Multi-layer magnetic thin film disks comprising a synthetic resin layer on an aluminum-containing substrate and an overlying metallic magnetic layer, are liable to have pin holes in the synthetic resin layer caused by galvanic corrosion of the aluminum in the substrate. The pin holes are passivated by aluminum oxide produced therein by anodically oxidizing the aluminum of the substrate in an electrolytic bath, the electric voltage of which is well below the normal passivation voltage for aluminum.

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Boblingen, Germany

Werner Steiner