Semiconductor lead frame
First Claim
1. A lead frame for a resin-sealed semiconductor package, having outer leads and inner leads with tips and formed by etching a blank;
- whereinthe tips of the inner leads have a thickness smaller than that of other portions of the lead frame;
the tip of each inner lead has an upper surface depressed relative to one of the surfaces of each of other portions of the lead frame, and a lower surface flush with other lower surfaces of each of other portions of the lead frame; and
both of the opposite surfaces of the tip of each inner lead have areas greater than the sectional area of the middle portion with respect to the thickness of the tip of the same inner lead; and
the upper surface of the tip of each inner lead is formed by etching the blank to form an etched recess with a flat bottom so that each inner lead has a tip wherein the upper surface of the tip is in a level plane.
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Abstract
A method for producing a lead frame having outer leads and inner leads, for use in constructing a resin-sealed semiconductor package comprises etching processes for etching a blank. A first resist pattern having a first opening and a second resist pattern having second openings are formed on the first and the second major surfaces of a blank. The first and the second major surfaces of the blank are etched through the first and the second resist pattern by a first etching process using a first etchant to form a first recess corresponding to the first opening and second recesses corresponding to the second recesses in the first and the second major surfaces, respectively. The first recess is filled up with an etch-resistant layer. The second major surface is etched through the second resist pattern by a second etching process using a second etchant so that portions of the blank corresponding to the second openings of the second resist pattern are etched through to form the tips of the inner leads.
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Citations
3 Claims
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1. A lead frame for a resin-sealed semiconductor package, having outer leads and inner leads with tips and formed by etching a blank;
- wherein
the tips of the inner leads have a thickness smaller than that of other portions of the lead frame; the tip of each inner lead has an upper surface depressed relative to one of the surfaces of each of other portions of the lead frame, and a lower surface flush with other lower surfaces of each of other portions of the lead frame; and both of the opposite surfaces of the tip of each inner lead have areas greater than the sectional area of the middle portion with respect to the thickness of the tip of the same inner lead; and the upper surface of the tip of each inner lead is formed by etching the blank to form an etched recess with a flat bottom so that each inner lead has a tip wherein the upper surface of the tip is in a level plane. - View Dependent Claims (2, 3)
- wherein
Specification