Method of metal lead frame and structure thereof

Abstract

This application discloses a metal leadframe structure, comprising a metal substrate, a crystal implantation area, connecting rods, lead pins, and a nano-bicrystalline copper plating layer. The crystal implantation area is formed on the metal substrate; a frame surrounds the outer perimeter of the crystal implantation area; the connecting rods connect the crystal implantation area and the frame; the lead pins are spaced apart, each lead pin including an outer lead pin adjacent to the frame and an inner lead pin adjacent to the crystal implantation area, the top surface width of each inner lead pin being greater than its corresponding bottom surface width; the nano-bicrystalline copper plating layer is applied to each inner lead pin. This improves the reliability of the leadframe in the wire bonding process and increases the yield of the finished product.

Claims

1. A method for manufacturing a metal conductor frame, comprising the following steps: A) Provide a metal substrate; B) A molding process is performed on the metal substrate to form a crystal implantation area, a frame surrounding the crystal implantation area, a plurality of connecting rods connecting the crystal implantation area and the frame, and a plurality of leads between the crystal implantation area and the frame, each lead including an outer lead adjacent to the frame and an inner lead adjacent to the crystal implantation area, the top surface width of each inner lead being greater than its corresponding bottom surface width; C) A grinding process is applied to the top surface of each inner lead; D) An electroplating process is applied to each inner lead to form a nano-bicrystalline copper plating layer on the surface of each inner lead; and E) A silver plating process is applied to each inner lead to form a silver plating layer on the top surface of the nano-bicrystalline copper plating layer of each inner lead.

2. The method for manufacturing a metal lead frame as described in claim 1, further comprising a step F) following step D), wherein a through groove is formed between any two adjacent leads, and step F) involves applying an injection resin process to each lead to form a resin seal in each through groove.

3. The method for manufacturing a metal lead frame as described in claim 1, wherein the forming process is an etching process.

4. The method for manufacturing a metal lead frame as described in claim 1, wherein the forming process is a stamping process.

5. The method for manufacturing a metal lead frame as described in claim 4 further includes a step B1) after step B), wherein step B1) is to punch and flatten the burrs on each of the inner leads of the metal substrate.

6. A metal lead frame structure, comprising: A metal substrate; A crystal implantation region is formed on the metal substrate; A border is set around the outer perimeter of the crystal-planting area; A plurality of connecting rods connect the crystal implantation area and the frame; a plurality of guide pins are spaced apart, each guide pin includes an outer guide pin adjacent to the frame and an inner guide pin adjacent to the crystal implantation area, the top surface width of each inner guide pin is greater than the corresponding bottom surface width; a nano-bicrystalline copper plating layer is coated on each inner guide pin; and a silver plating layer is coated on the top surface of the nano-bicrystalline copper plating layer of each inner guide pin.

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