UC San Diego
Nanograin Copper Deposition Using an Impinging Jet Electrode
- Author(s): Swingle, Karen Diane
- et al.
Nanograin copper has applications as an interconnect material for microelectronics, telescope mirrors and semi- mirrors for UV filters. Electrodeposition is the preferred method for obtaining nanograin copper due to its low cost and current use in industry. Impinging jet electrode (IJE) plating systems have plating rates that can be up to 10 times faster than conventional methods. In this research the use of a circular, unsubmerged IJE for creating copper films on platinum and nickel substrates was investigated. Specifically, the limits of the process parameters for the IJE system of flow rate (2.5 or 7 L/min) and current density (10 or 200 mA/cm²). Also, the process of self- annealing, grain growth at room temperature, of the copper deposits was investigated. It was found that copper films could be electrodeposited with average grain sizes of approximately 40 nm. Smaller grain sizes were associated with a low flow rate, while a higher flow rate gave larger grains. Grain size did not vary with current density. Self -annealing was observed for deposits made with a high flow rate and grain growth occurred for at least a month. After 8 months only the deposits made using a low flow rate still had grains under 100 nm in size