ELECTROLESS NICKEL / IMMERSION GOLD PROCESS TECHNOLOGY FOR IMPROVED DUCTILITY OF FLEX AND RIGID-FLEX APPLICATIONSAuthors: Kuldip Johal and Hugh Roberts et al.
Company: Atotech USA Inc.
Date Published: 2/25/2005 Conference: Pan Pacific Symposium
To avoid cracking of the nickel during bending, the use of ENIG for flex and rigid-flex circuits has typically required a relatively thin electroless nickel deposit of medium phosphorus content. In this technical paper, the reliability of ENIG with high-phosphorus electroless nickel is examined for such applications. Using electroless nickel deposits of varying thickness and phosphorus content, results of bending tests, hardness, and SEMs are compared to predict reliability of the assembled flexible circuit.
In particular, Young's Modulus (stress-to-strain ratio) is evaluated to show a direct relationship between the phosphorus content of the electroless nickel deposit and the ductility of the overall ENIG finish. The ENIG process with high-phosphorus nickel is shown to offer a more reliable surface finish for flex and rigid-flex applications.
Members download articles for free:
Not a member yet?
What else do you get when you join SMTA? Read about all of the benefits that go along with membership.
Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.