Enhanced Galvanic Process For A2 Leadframe Package Processability Improvement
Original Publication Date: 2004-Jun-25
Included in the Prior Art Database: 2004-Jun-25
Related PeopleOther Related People:
One step in the assembling of a semiconductor device package is to form electrical connections between electrical contact areas on the semiconductor device and electrical areas on the leadframe. The use of A2 plated leadframes for the enhancement of the moisture sensitivity level can cause the problem of a loose solder and compound residues after the galvanic (GA) process. The standard GA process is unable to remove the mold runner gate compound residue completely because it is strongly adhered to the A2 plated frame. A loose fragile layer of solder will be formed on this partially conductive surface of the mold runner gate which resulted in accelerating solder and compound residue accumulation on the trim and form tool (TF2). The elimination of loose solder and compound residue on the A2 plated frame is improved now. With the knowledge that the A2 layer on the frame is easily susceptible under an acidic condition, the idea is to introduce an acid based treatment on the material prior to the GA process step. Investigation proved that it is possible to eliminate the loose solder and compound residue by introducing a diluted sulfuric acid (H2SO4 10% in deionized water) dipped to the electrolytic deflashing (ED) in the GA process. Further tests carried out at the TF2 also proved that an immediate reduction in solder and compound residue accumulation on the tools can be achieved, and thus restoration of the equipment capacity and product quality is possible by this solution.