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COPPER PREPARATION FOR ACTIVE TRIMMING BY Y.A.G. LASER

IP.com Disclosure Number: IPCOM000005958D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2001-Nov-20
Document File: 1 page(s) / 56K

Publishing Venue

Motorola

Related People

Len Anderson: AUTHOR [+3]

Abstract

Laser trim tuning involves the use of a laser to cut away sections of a metallic trim flag on an RF (Radio Frequency) printed circuit board or ceramic substrate resulting in a desired change in the RF characteristics of the circuit, in effect tuning the circuit.

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MOlDROLA Technical Developments Volume 11 October 1990

COPPER PREPARATION FOR ACTIVE TRIMMING BY Y.A.G. LASER

by Len Anderson, Ray Buckley and Pat Goodspeed

   Laser trim tuning involves the use of a laser to cut away sections of a metallic trim flag on an RF (Radio Frequency) printed circuit board or ceramic substrate resulting in a desired change in the RF characteristics of the circuit, in effect tuning the circuit.

   Laser light that is not reflected from the surface of the target object (the trim flag) is generally absorbed by the object. In order for laser light to be useful for cutting, it must be absorbed by the material. This absorption converts the light energy into heat energy, raising the temperature of the material. The amount of light absorbed depends on things such as the characteristics of the material and its surface conditions. The surface of most materials contain sur- face films of greases and other predominantly organic contaminants, as well as absorbed gases. Reactive metals, such as copper, will always have an oxide or other inorganic films. The presence of these films and metal compounds will have an influence of the interaction of laser energy with the surface of the target material.

   To ensure predictable and Consistent interaction between the IaSer and target material, in this case copper, the surface of the trim area is preconditioned for laser trimming. To prepare the trim area of the target object, fine sand (Si02) is forced through a...