Through-Hole Filling with Copper Electroplating by Using Different Acids and Anode Materials

• Main Authors: Yu-Tien Lin, 林宇恬
• Other Authors: 竇維平
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/72415671412949006613

碩士 === 國立中興大學 === 化學工程學系所 === 103 === Nowadays, the contact distance between electronic devices has become much shorter with the trend of electronic product miniaturization. To achieve this goal, Electronic devices that have narrow line widths and high density interconnect(HDI) are being vigorously developed. IC chip packaging will benefit from two-dimensional connection turning towards three-dimensional stacking technology. However, the volume shrinkage in electronic devices results in a high aspect of conducting through-holes that are used as the message channels. The high aspect ratio through hole renders current density distribution in the hole and at the hole mouth to be not uniform during copper plating which increases difficulty in copper superfilling of through holes. For this reason, many people added chemical additives in the copper plating solution, but the more additives in the plating solution, the more complicated mechanism in the copper plating. Soluble anode is usually applied to copper electroplating in a traditional plating bate. However, soluble anode has some disadvantages, such as surface area change with time, which causes non-uniform distribution of current density and uneven plated film thickness. This may affect product reliability and stability of the plating bath. Because of the disadvantage of soluble anodes, functional insoluble anode is used to substitute for the soluble anode in industry. In order to discuss the influence on the filling performance of different anode materials, conventional soluble anodes (i.e., P-doped Cu) and functional insoluble anodes that were activated with iridium-based mixed metal oxides on Ti meshes were used during the electroplating experiment. Through-hole (TH) filling of a printed circuit board (PCB) was conducted with a copper electroplating solution by using sulfuric acid as a supporting electrolyte. To investigate the effect of acids with different anode materials, the acetic acid electrolyte was used instead of sulfuric acid for the copper electroplating. The TH filing performance of the copper electroplating solution was significantly enhanced when acetic acid electrolyte and insoluble anodes were used simultaneously in the copper electroplating bath.