Texas Instruments Corporation

Gijsbert Willem Lokhorst

Paul R Moehle

Robert M Fritzsche

Harold T Kelleher

Ronald B Wheelock

A method of fabricating a lead frame. The method includes providing an electrically conductive layer having a pair of opposing major surfaces. A pattern is etched in the layer extending partially through the layer to form cavities with sidewalls in the layer. A patterned mask is provided on the etched layer including masking of the sidewalls. The layer is again etched within the cavities. The patterned mask is preferably a liquid photo resist and the electrically conductive layer is preferably one of a copper or copper-based material or ALLOY 42. The etch can take place from both major surfaces.

Two pass process for producing a fine pitch lead frame by etching

The invention is a method for making a lead frame (,) having fine pitched lead frame leads (,). A first side of the lead frame material is etched to for the lead frame and define the lead frame leads and die pad, but the etch process does not etch completely through the lead frame material. The partially etched first side is then covered with a tape (,) or layer of photoresist (,). The second side of the lead fame material is then etched to complete the lead frame. The lead frame may then be plated.

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Gijsbert Willem Lokhorst