Adhesion strength and microstructural evaluation in electroless Ni-P metallized AlN substrate

Abstract

The adhesion strength of the electroless Ni (EN)plated AlN substrates is studied through investigation of the microstructural morphologies at the AlN-EN interfaces. Etching sites around the Al-Y-O compounds on the etched AlN substrate provide the anchor acceptors for interlocking the EN film to achieve a high adhesion strength. Separation of the EN film from the AlN substrate under the action of force leaves the fracture cracks propagating along the AlN/EN interface, cutting through the anchors and making the fragmental EN films around the etching sites resided on the AlN fracture surface. However, the polished AlN substrate lacks the interlocking sites and fails to obstruct the cracks propagating along the AlN/EN interface, and thus results in a poor adhesion strength. An appropriate adhesion strength of 13.7 MPa with a small standard deviation (62.3 MPa) can be obtained for the previously etched and 10 m thick EN-plated AlN substrate.

High-adhesion Cu patterns fabricated by nanosecond laser modification and electroless copper plating

“…Yoshiki et al [11] reported an electroless copper layer on ceramic substrate with the adhesion strength of greater than 25 MPa by using an intermediate layer of ZnO thin film, which was prepared by spray pyrolysis. Although high temperature favor the formation of strong chemical bonding between the ZnO film and the substrate, the residual stress needs to be reduced by annealing for as long as 2 h. Chung-Daw and Jenq-Gong [12] etched the ceramic substrate using a 4 wt.% NaOH solution for 3 h to obtain a rough surface, and an adhesion strength of 13.7 MPa was achieved. However, the inefficient pretreatments are likely to limit the practical use of this technique.…”

Direct Copper Pattern Plating on Glass and Ceramic Substrates Using an Al-Doped ZnO as an Adhesive and Conducting Layer

“…Roughening their surfaces and then using electroless deposition was a common approach. 27,[33][34][35][36][37][38][39][40][41] Surface metallization, mask design, photoresistant coating, exposure, development, and then pattern etching are the standard operation process (SOP) for RDL formation on the ceramic substrates. The SOP takes a long time and is expensive, even high risk, because the process flow is long, the palladium used as the catalyst of the electroless deposition is expensive, and after baking the copper electroless deposition layer, copper blister may be formed on the substrates.…”