Effect of bath temperature for cu electroless deposition onto acrylon nitril butadiene (ABS) insulating substrate

In this work, we will show results of study on the influences of bath temperature on deposition rate and structure, morphology, mechanical properties of Cu electrolessly deposited films onto Acrylon Nitril Butadiene (ABS) surface.
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Effect of bath temperature for cu electroless deposition onto acrylon nitril butadiene (ABS) insulating substrateJournal of Chemistry, Vol. 44 (5), P. 642 - 647, 2006 EFFECT OF BATH TEMPERATURE FOR Cu ELECTROLESS DEPOSITION ONTO ACRYLON NITRIL BUTADIENE (ABS) INSULATING SUBSTRATE Received 8 August 2005 MAI THANH TUNG, LAI HUY NAM Dept. of Electrochemistry and Corrosion Protection, Hanoi University of Technology SUMMARY Influences of bath temperature (Tbath) on Cu electroless deposition rate and on morphology, structure, corrosion resistivity of deposited Cu layers were investigated. Results showed that the increasing Tbath from 25 to 70oC resulted an increase of the deposition rate, while the deposition rate decreased as Tbath increased from 70 to 90oC due to the bulk reduction of Cu2+. SEM results indicated that the crystals of deposited layers became finer as Tbath increased. XRD analyses showed that mean grain size Lmean decreased and intensity ratio I(111)/I(200) increased remarkably with increasing Tbath from 25 to 70oC and changes of both Lmean and I(111)/I(200) are less pronounce in the range of Tbath = 70 - 90o. The corrosion resistivity increased remarkably with increasing Tbath from 25 to 70oC and became nearly invariable the range of Tbath = 70 - 90o. These results were explained by the relation between structure and corrosion properties of the electrolessly deposited Cu layers. I - INTRODUCTION deposition bath contains metal sources (Cu2+) and a reducing agent (HCHO) and the Electroless deposition technique has been deposition occurs following two reactions [6, 7]:intensively studied due to its important Cathode process: Cu2+ + 2e Cu (1)applications in electronics, surface technologyand modern micro- and nanotechnology [1 - 4]. Anode process:The main advantage of the electroless 2HCHO + 4OH- 2HCOO- + 2H2O + 2e (2)deposition technique is the possibility to formmetal layers on insulating and semiconducting (The process (2) is initiated on surfaces ofsubstrates. Among the metals used for activators Pd, Pt)electroless deposition, Cu is one of the most Since kinetics of the deposition process areimportant materials due to its high conductivity controlled by both processes (1) and (2), theand good mechanical properties. Therefore, the deposition rate and structure, morphology,Cu electroless deposition became the key mechanical properties of deposited films areprocess in printed circuit boards (PCBs) influenced by activators, bath composition andproduction and metallization process in plastic temperature. It has been shown in severalindustry [1 - 7]. The Cu electroless deposition studies that bath temperature plays a veryprocess is based on the so-called autocatalytic important role during the plating process andeffect of Cu2+ reduction when electrocatalytic decides structure and properties of the obtainedmetals such as Pt, Pd (activators) are present on layers [2, 6 - 8].the surfaces [6 - 8]. Typically, the Cu electroless642 In this work, we will show results of study ABS plastic. Prior to the plating, the ABSon the influences of bath temperature on samples were polished, degreased and rinseddeposition rate and structure, morphology, carefully. In order to prepare rough andmechanical properties of Cu electrolessly hydrophilic ABS surfaces, samples weredeposited films onto Acrylon Nitril Butadiene pretreated in etching solution (CrO3 150 g/l,(ABS) surface. H2SO4 400 g/l, t = 70oC). The electroless deposition process consisted of 3 steps: II - EXPERIMENTAL sensization, activation and electroless deposition. Solutions and conditions for the The electroless deposition was performed on processes are given in table 1. Table 1: Solutions and conditions of the Cu electroless deposition steps Step Solution Temperature pH Duration oSensization (BK-PLAC-sens) 1g/l SnCl2.2H2O +surfactance 25 C - 2 min oActivation (BK-PLAC-act) 0,1 ...