Low Defect Density Electrodeposits on Copper Single Crystals

Abstract

The electrodeposition of layers of copper over I00 ~m thick on copper single crystals has been carried out on highly perfect copper single crystal substrates, having {111} orientation. Conditions for the achievement of low defect density deposits have been investigated. The defects present in the deposit have been studied by Borrmann topography and other x-ray techniques as well as optical microscopy and dislocation etching. In the most perfect deposits produced, no mosaic structure has been found, and the concentration of defects visible by Borrmann topography did not increase substantially the absorption of the x-ray beam. Small loops or point defect clusters in concentrations of the order of 106/cm 2 have been detected by etching. The orientation of the substrate has been found to affect the perfection of the deposits. It is concluded that random nucleation is likely to be the mechanism for step generation where the orientation is very close to {111}.

Effects of Temperature on the Comproportionation of Metallic Copper and Cupric Ions to Cuprous Ions

“…Deposition of metallic copper from cupric ions is generally accepted to take place via cuprous ion intermediates ,. In addition, cuprous ions form through the comproportionation reaction of cupric ions and metallic copper ,. Commercial plating electrolytes further contain organic additives to influence the deposit properties and to allow feature filling,, which is ascribed to their interaction with cuprous ions ,.…”

“…Formation of cuprous ions in the electrolyte occurs via a comproportionation reaction of cupric ions and metallic copper according to Equation (1). Based on this reaction, the corresponding equilibrium constant may be described by Equation , …”

“…[6,[10][11][12] In addition, cuprous ions form through the comproportionation reaction of cupric ions and metallic copper. [6,[10][11][12][13][14][15] Commercial plating electrolytes further contain organic additives to influence the deposit properties and to allow feature filling, [6,[16][17][18] which is ascribed to their interaction with cuprous ions. [6,19] Therefore, in order to understand the effects of temperature on the plating process, proper understanding of the impact of thermal energy on the cuprous ion comproportionation equilibrium is required.…”

“…Based on this reaction, the corresponding equilibrium constant may be described by Equation (2). [6,[10][11][12][13][14][15] Cu þ Cu þ2 G K H 2Cu þ1 ð1Þ…”

Influence of the Temperature-Dependent Cu+1-Accelerator Complex Formation on Through-Silicon Via Filling

“…[10][11][12][13] In addition, cuprous ions form through the comproportionation reaction of cupric ions and metallic copper. [10][11][12][13][14][15][16] Industrially relevant plating electrolytes further contain organic additives, which impact on the deposit properties and allow feature filling. 10,[17][18][19] The effects of such additives on copper deposition are ascribed to their interaction with cuprous ions.…”