Acid Resistance after Multibond SR and Multibond Enhancer Plus:

The oxidation of copper surfaces prior to the bonding of inner layers is a critical prerequisite for the production of high quality circuit boards. The oxide layer ensures enhanced bonding between the inner layers and prepregs used in multilayer manufacture. All processing technologies have been tested to their limits as a result of higher layer counts, finer lines, smaller holes and blind via technology. Bonding processes are no exception and the rapid growth of direct metallization in the market place has further compounded these issues.

To meet these challenges Atotech has further developed and optimized its oxidation process to ensure that a uniform, fine-grained crystal structure is formed, which gives extremely high bond strengths. 

Multibond SR Stabilized Reduction Solution improves the overall operating window of the system, enhancing the acid resistance without affecting peel strengths.

The Stable Solution - Multibond SR

Multibond SR Stabilized Reduction Solution converts the copper oxide formed in the oxide bath to metallic copper as follows:
Cu²⁺ + 2e^- > Cu⁰
Cu¹⁺ + 1e^- > Cu⁰
Although the surface of the oxide remains largely unchanged, the resistance to chemical attack is greatly enhanced, thus eliminating "pink ring" and greatly reducing the problem of "wedge voiding".

The unique formulation of Multibond SR prevents decomposition of the active ingredient of Multibond SR during periods of downtime, and also prevents crystallization of the concentrate during storage, thus lowering overall process costs. The improved chemical resistance offered by Multibond SR is extremely important when using a direct plate process.

Features and Benefits

• High peel strength and thermal reliability
• Excellent acid resistance to eliminate pink ring
• Wedge void free in direct plating
• Wide process window and stable reduction performance