Method for semiconductor leadframes in low volume and rapid turnaround
AssigneeTexas Instruments Incorporated
InventorSreenivasan K. Koduri
Life of this patent
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Abstract
A method for fabricating a leadframe for a QFN/SON semiconductor device by selecting (301) a strip of a first metal as the leadframe core, then plating (302) a layer of a second metal over both surfaces of the strip, then cutting (304) a pattern from the pre-plated strip and further removing (304) portions of the second metal layer over a surface to expose the underlying core first metal. The exposed core first metal oxidized (305) before using (306) the leadframe for assembling the semiconductor device. The steps of cutting and removing are performed programmable machining techniques such as computer numerical controlled tools (CNC), electrical discharge machining (EDM), laser cutting, and water jet cutting.
Claims17
A method for fabricating an apparatus comprising the step of:
- cutting a pattern including a pad and a plurality of leads by cutting through a strip, the strip having a core of a first metal and a plated surface layer of a second metal, to expose the core first metal at side walls of the leads and the pad;
- and
- attaching a semiconductor chip on the pad.
A method for fabricating a semiconductor device, comprising:
- providing a metal strip having a core first metal, of which a surface is covered by a layer of second metal different from the core first metal;
- cutting through the metal strip with a programmed cutting machine to form pad and leads exposing the core first metal at sidewalls of the formed pad and leads;
- removing additional second metal with the programmed cutting machine to expose a portion of the first metal surface;
- and affixing a semiconductor chip on the pad.
Dependencies are inferred from the claim text.