Effects of Copper Brighteners on Throwing Power and Thermal Reliability of Plating Through Holes

• Main Authors: Tsu-Chi Chen, 陳祖啟
• Other Authors: 竇維平
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/31020227311338658064

碩士 === 國立中興大學 === 化學工程學系所 === 105 === High aspect ratio through holes are commonly designed in printed circuit boards (PCBs) with a high density interconnection. In this study, the PCB sample are metalized by Cu electroless deposition and then by Cu electroplating. When electroplating, adding three different brighteners to achieve high throwing power and good thermal reliability with the plated through holes (PTHs). In this study, using the three different brightener include 3-Mercapo-1-1-Propanesulfonate (MPS)、3-(Amidinothio)-1-propanesulfonic acid (UPS)、Sodium 3-(benzothiazol-2-ylthio)-1-propanesulfonate (ZPS) with the basic electrolyte which are 60g/l copper sulfate、10% sulfuric acid、PEG8000 200ppm and Cl- 60ppm. The electroplating time is 1.5 hours. In the electrochemical experiments, the acceleration effect of adding MPS is the most obvious. The electroplating results shows that adding 1 ppm MPS, or 10 ppm UPS, or 20 ppm ZPS have goof effect for throwing power and thermal shock test. With higher UPS or ZPS concentration adding in the electrolyte, the results show that throwing power decrease and fail thermal shock test. It can be seen that the stress on the copper layer increase with UPS or ZPS adding in the electrolyte. Moreover, the orientation which electroplated copper with UPS or ZPS is prefer <220>, the modulus of elasticity of <220> is lower than <111>, so that the reasons of failing in the thermal shock test are associated to the stress that produced when electroplating and the copper orientation. To achieve high throwing power and pass thermal shock test, different brighteners and concentration are showed in this study. Adding UPS or ZPS in the electrolyte affects the stress on the copper layer and the copper orientation which are the keys to the result of the thermal shock test. Keyword: Copper Plating Brightener, Throwing Power, Thermal Reliability.