Producing metal/ceramic circuit board by removing residual silver
AssigneeDowa Metaltech Co., Ltd.
InventorsTakashi Ideno, Ayumu Ozaki, Koji Kobayashi
Life of this patent
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Abstract
After a copper plate 14 is bonded to at least one surface of a ceramic substrate 10 via an active metal containing brazing filler metal 12 which contains silver, the unnecessary portion of the copper plat 14 and active metal containing brazing filler metal 12 is removed, and thereafter, an unnecessary portion of the copper plate 14 is removed by chemical polishing so as to cause the active metal containing brazing filler metal 12 to protrude from the side face portion of the copper plate 14, and then, a silver layer 18 adhered to the surface of the copper plate 14 by the chemical polishing is removed.
Claims8
A method for producing a metal/ceramic circuit board, the method comprising the steps of:
- bonding a copper plate to at least one surface of a ceramic substrate via an active metal containing brazing filler metal which contains silver;
- removing an unnecessary portion of the copper plate;
- removing an unnecessary portion of the active metal containing brazing filler metal;
- thereafter, removing an additional unnecessary portion of the copper plate by chemical polishing so as to cause the active metal containing brazing filler metal to protrude from a side face portion of the copper plate while causing the silver to be adhered to a surface of the copper plate to form a silver layer thereon;
- and
- removing the silver layer from the surface of the copper plate.
Dependencies are inferred from the claim text.