Ohkuchi Materials Co., Ltd.

Hidehiko Sasaki

Kaoru Hishiki

Keiichi Otaki

Kotaro Tomeoka

A lead frame includes, as an outermost plating layer, a roughened silver plating layer having acicular projections and covering only top faces on the upper surface side of a lead frame substrate made of a copper-based material. The roughened silver plating layer has a crystal structure in which the crystal direction &#x3c;101&#x3e; occupies a largest proportion among the crystal directions &#x3c;001&#x3e;, &#x3c;111&#x3e;, and &#x3c;101&#x3e;. The lead frame can be manufactured with improved productivity owing to reduction in cost and operation time, and achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer to be thin.

Lead frame

A substrate for mounting a semiconductor element thereon has columnar terminal portions formed by concavities provided on an upper surface of a metal plate made of a copper-based material, and is provided with a roughened silver plating layer having acicular projections, applied, as the outermost plating layer, to top faces of the columnar terminal portions. The roughened silver plating layer has a crystal structure in which the crystal direction &#x3c;101&#x3e; occupies a largest proportion among the crystal directions &#x3c;001&#x3e;, &#x3c;111&#x3e; and &#x3c;101&#x3e;. The substrate for mounting a semiconductor element thereon facilitates thin design of semiconductor packages produced by flip-chip mounting, can be manufactured with improved productivity owing to reduction in cost and operation time, achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer to be thin.

Substrate for mounting semiconductor element

A lead frame includes, as an outermost plating layer, a roughened silver plating layer having acicular projections and covering top faces and faces that form concavities or a through hole between the top faces and bottom faces of a lead frame substrate made of a copper-based material. The roughened silver plating layer has a crystal structure in which the crystal direction &#x3c;101&#x3e; occupies a largest proportion among the crystal directions &#x3c;001&#x3e;, &#x3c;111&#x3e;, and &#x3c;101&#x3e;. The lead frame can be manufactured with improved productivity owing to reduction in cost and operation time, and achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer to be thin.

A device for mounting a semiconductor element includes a metal plate serving as a base, a roughened silver plating layer with acicular projections, formed on at least either of: (a) top faces; and (b) faces that form concavities or through holes between the top faces and bottom faces; of the metal plate, and a reinforcing plating layer covering, as an outermost plating layer, an outer surface of the acicular projections in the roughened silver plating layer. The roughened silver plating layer has a crystal structure in which the crystal direction &#x3c;101&#x3e; occupies a largest proportion among the crystal directions &#x3c;001&#x3e;, &#x3c;111&#x3e;, and &#x3c;101&#x3e;. An outer surface of the reinforcing plating layer is shaped to have acicular projections with a surface area ratio of 1.30 or more and 6.00 or less to the corresponding smooth surface, as inheriting the shape of the acicular projections in the roughened silver plating layer.

Device for mounting semiconductor element, lead frame, and substrate for mounting semiconductor element

A lead frame includes a lead frame substrate made of a copper-based material, plating layers composed of nickel, palladium and gold layers laminated in this order on top faces and bottom faces of the lead frame substrate, and a roughened silver plating layer having acicular projections, provided as an outermost plating layer and covering faces of the lead frame substrate that form concavities or a through hole between the top faces and the bottom faces of the lead frame substrate. The roughened silver plating layer has a crystal structure in which the crystal direction &#x3c;101&#x3e; occupies a largest proportion among the crystal directions &#x3c;001&#x3e;, &#x3c;111&#x3e; and &#x3c;101&#x3e;. The lead frame can be manufactured with improved productivity owing to reduction in cost and operation time, and achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer to be thin.

A substrate for mounting a semiconductor element thereon includes a metal plate and columnar terminal portions composed only of plating layers and formed on one-side surface of the metal plate. The columnar terminal portions include, as an outermost plating layer, a roughened silver plating layer having acicular projections. The roughened silver plating layer has a crystal structure in which the crystal direction &#x3c;101&#x3e; occupies a largest proportion among the crystal directions &#x3c;001&#x3e;, &#x3c;111&#x3e; and &#x3c;101&#x3e;. The substrate for mounting a semiconductor element thereon can be manufactured with improved productivity owing to reduction in cost and operation time, and achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer, which are to serve as terminals and the like, to be thin.

A lead frame includes, as an outermost plating layer, a roughened silver plating layer having acicular projections and covering the entire surface of a lead frame substrate made of a copper-based material. The roughened silver plating layer has a crystal structure in which the crystal direction &#x3c;101&#x3e; occupies a largest proportion among the crystal directions &#x3c;001&#x3e;, &#x3c;111&#x3e;, and &#x3c;101&#x3e;. The lead frame can be manufactured with improved productivity owing to reduction in cost and operation time, and achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer to be thin.

Growing community of inventors

Isa, Japan

Hidehiko Sasaki