| WANG Lie-yan,ZHU Chao-feng,LIN Chuo-hong,CAI Yang-lun.A New Technology for Preventing Plating Cracks of 4J29 Lead Frame[J],46(6):282-286 |
| A New Technology for Preventing Plating Cracks of 4J29 Lead Frame |
| Received:January 23, 2017 Revised:June 20, 2017 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2017.06.045 |
| KeyWord:4J29 alloy lead frame electronic packaging heat treatment electroplating electronickelling electrogilding |
| Author | Institution |
| WANG Lie-yan |
School of Materials Science and Environmental Engineering, Beijing Institute of Technology, Zhuhai , China |
| ZHU Chao-feng |
School of Materials Science and Environmental Engineering, Beijing Institute of Technology, Zhuhai , China |
| LIN Chuo-hong |
School of Materials Science and Environmental Engineering, Beijing Institute of Technology, Zhuhai , China |
| CAI Yang-lun |
School of Materials Science and Environmental Engineering, Beijing Institute of Technology, Zhuhai , China |
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| Abstract: |
| The work aims to prevent 4J29 fine wire from breaking and plating local cracking during Ni/Au or Ni/Pd/Au plating. By comparison and contrast, appearance quality of the fine-wire plating was observed using a 200× magnifying glass before and after the plating process was changed or adjusted, and then bending test was performed to observe whether the electroplated fine-wire was subject to breaking or cracking, products subject to such defects were counted, and defect rate was calculated. Heat treatment of the workpiece before electroplating could eliminate crack of the thin frame after the workpiece was electroplated. By changing composition and process conditions of electronickelling working solution, local cracking of the plated workpiece could be effectively resolved. Operating conditions of heat treatment were as follows: temperature of 420~450 ℃, holding time of 120 min, cooling mode of natural cooling to room temperature; electronickelling process specification was as follows: 250~350 g/L of nickel sulfamate, 25~35 g/L of boric acid, 0.01 g/L of wetting agent (K12), saccharin of 0.3~0.4 g/L, pH of 3~5, temperature of 50~60 ℃, current density of 3.0~5.0 A/dm2. A new electroplating process is developed to prevent fine wires from breaking and the plating from cracking after 4J29 lead frame is electroplated. After actual use by enterprises, and sampling each uniwaver for ten 90° bending tests, defective rate of the products produced in new electroplating process falls within 2% and other performance tests meet enterprise product quality requirements as well. |
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