Lucent Technologies Inc.

At+t Corp.

At&t Bell Laboratories

Gideon S Grader

John Thomson, Jr

David W Johnson, Jr

Debra Anne Fleming

David Wilfred Johnson

Apurba Roy

Vincent George Lambrecht, Jr

Henry M O'Bryan, Jr

Warren W Rhodes

The invention provides an improved process for fabricating devices containing metallized magnetic ceramic material, such as inductors, transformers, and magnetic substrates. In particular, the unique vias utilized in the process of the invention allow fabrication of devices from multiple unfired ferrite layers with only a single via-coating step, thereby avoiding the need numerous punching steps. Moreover, there is no need for expanding the dimensions of the vias and thus no need for internal metallization. The invention therefore provides for green tape-type fabrication of devices such as inductors, transformers, and magnetic substrates in a manner faster, less complex, and more reliable than current methods. The invention also relates to use of an improved conductive material in such a process, the conductive material containing silver/palladium particles, ferrite particles, a cellulose-based or other organic binder, and a solvent. After firing of the substrate onto which the ink has been coated, and plating of copper thereon by a copper pyrophosphate bath, the plated copper exhibits a pull strength greater than about 4 kpsi, advantageously greater than about 5 kpsi. Use of a copper pyrophosphate bath also allow uniform plating within long, narrow vias.

Process for forming device comprising metallized magnetic substrates

Magnetic components are fabricated as monolithic structures using multilayer co-fired ceramic tape techniques. Fabrication of these magnetic components involves constructing multiple layers of a magnetic material and an insulating non-magnetic material to form a monolithic structure with well defined magnetic and insulating non-magnetic regions. Windings are formed using screen printed conductors connected through the multilayer structure by conducting vias.

Method of making a multilayer monolithic magnetic component

This invention is predicated upon applicants' discovery that conventional techniques for minimizing metal loss from sintered ceramic materials are not adequate in the fabrication of small ceramic components such as multilayer monolithic magnetic devices wherein a magnetic core is substantially surrounded by an insulating housing. Applicants have determined that this metal loss problem can be solved by providing the component with a housing layer having an appropriate concentration of metal. Specifically, if the insulating housing material around the magnetic core has, during the high temperature firing, the same partial pressure of metal as the magnetic core material, there is no net loss of metal from the core. In a preferred embodiment, loss of zinc from a MnZn ferrite core is compensated by providing a housing of NiZn ferrite or zinc aluminate with appropriate Zn concentrations. Similar considerations apply to other ceramic components.

Sintered ceramic components and method for making same

Magnetic components are fabricated as monolithic structures using multilayer co-fired ceramic tape techniques. Fabrication of these magnetic components involves constructing multiple layers of a magnetic material and an insulating non-magnetic mataerial to form a monolithic structure with well defined magnetic and insulating non-magnetic regions. Windings are formed using screen printed conductors connected through the multilayer structure by conducting vias.

Method of making a multilayer monolithic magnet component

Growing community of inventors

Haifa, Israel

Gideon S Grader