Function Of Plate Parameters Research Articles

Material Analysis of Lead Free Solder Deposited by Electrochemical Deposition

Lead-free solders have essentially replaced lead-tin solders for new microelectronic applications. At the same time, many products are continuing to go through miniaturization, so the behavior of the solder material is changing as a function of the connection size. As lead-tin solder has been replaced by lead-free alloys, electrodeposited SnAg has become the standard solder alloy used on wafers. Tin-based solders exhibit a complex material structure in the deposit, as recrystallization occurs in the deposit, and as intermetallic compounds form. Understanding the complex nature of these materials is becoming increasingly important to the performance of our electronic products. We have characterized ECD SnAg solder alloy deposits in terms of composition, grain size, phase, microstructure, and texture using EBSD analysis. We will discuss the effects of modifying the process parameters on the microstructure which could implications on the performance of the solder bump as a chip-level interconnect. We have seen that the metals deposit as β-tin with finely dispersed intermetallic grains. We have also seen evidence of recrystallization of the deposit subsequent to deposition, although the recrystallization behaviour is significantly different than the well-characterized copper recrystallization. Finally, the metal at the interface below the solder reacts with Sn to form intermetallic compounds, the compositions of which are dependent on the materials present. The effects of the process parameters on the deposit properties are becoming increasingly important to understand in order to control the properties of the interconnection, and how it changes over its lifetime. We have characterized the incorporation of trace organic materials in the deposit as a function of plating parameters. The deposition of SnAg from an MSA-based plating bath is very different from the deposition of copper from a copper sulfate plating bath. We have noticed that the incorporation of organic additive materials, as well as the grain size, increases as the deposition rate is increased in the deposition of SnAg.

Effects of electroless plating chemistry on the synthesis of palladium membranes

The effects of plating chemistry on palladium deposition, plating efficiency and membrane microstructure have been studied for two palladium electroless plating solutions, hydrazine-based and hypophosphite-based plating baths. The electroless plating kinetics of palladium onto seeded supports have been determined for hypophosphite-based plating bath, and a simple kinetic model has been developed. The model provides an accurate prediction of deposition rate and film thickness as a function of plating parameters. Most importantly, the experimental results demonstrated that plating chemistry plays a vital role on both plating performance and film microstructure.

Palladium composite membranes by electroless plating technique: Relationships between plating kinetics, film microstructure and membrane performance

Thin supported palladium membranes were prepared using electroless plating technique. The intrinsic plating kinetics were determined for hydrazine-based palladium plating baths. Mathematical models were developed to predict film thickness and plating rate as a function of plating parameters (i.e., reactant concentrations, temperature and time). Analyses of film surface microstructure indicate that grain structure is dependent on both plating chemistry and plating rate. The evolution of film morphology during electroless plating was also investigated. Hydrogen permeation study demonstrated that film structure has a significant influence on the permeation performance of the palladium membrane.

Palladium–silver composite membranes by electroless plating technique

The exact conditions for deposition of pure palladium and pure silver membranes as well as simultaneous, co-deposition of palladium and silver have been identified for a hydrazine-based plating bath containing both palladium and silver precursors. The electroless plating kinetics have been determined for co-deposition of palladium and silver from the mixed plating bath. A mathematical model has been developed to predict the film thickness, plating rate and composition profile as a function of plating parameters (i.e., reactant concentrations and time). The evolution of the microstructure and composition of the film during electroless plating has also been investigated. A hydrogen permeation study has demonstrated that the Pd–Ag alloy membrane has superior performance compared to a pure palladium membrane of similar thickness. In addition, the formation of a single-phase alloy results in substantial enhancement in the hydrogen permeation rate.