Decoding the suppressing effects of Pluronic triblock copolymers on copper electrodeposition

Area of Science:

• Materials Science
• Electrochemistry
• Surface Chemistry

Background:

• Triblock Pluronics (polyoxyethylene-polyoxypropylene-polyoxyethylene) are effective suppressors in copper electroplating for electronics manufacturing.
• The precise roles of polyoxyethylene (PEO) and polyoxypropylene (PPO) blocks in Pluronic suppressor function are not fully understood.
• Understanding these interfacial roles is critical for designing more efficient copper electroplating suppressors.

Purpose of the Study:

• To systematically investigate how Pluronic composition and block arrangement influence inhibition during copper electroplating.
• To elucidate the distinct interfacial roles of PEO and PPO blocks in Pluronic suppressors.
• To provide insights for the rational design of advanced copolymer suppressors.

Main Methods:

• Systematic investigation of Pluronic composition and block arrangement effects on copper deposition.
• Correlation analysis between electrodeposited copper mass, hydrophilic-lipophilic balance (HLB), and PPO content.
• Comparative analysis of normal and reverse Pluronic structures.
• Electrochemical attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) for interfacial adsorption studies.

Main Results:

• Increased PPO content in Pluronics correlates with decreased copper deposition mass, indicating PPO's primary role in inhibition strength.
• A positive correlation exists between electrodeposited copper mass and the hydrophilic-lipophilic balance (HLB) value.
• An adequately long PEO block is essential for maintaining the stability of Pluronic-based inhibition.
• ATR-SEIRAS confirmed that PEO blocks adsorb onto the copper surface over a chloridion adlayer, not PPO blocks.

Conclusions:

• The PPO block primarily dictates the inhibition strength of Pluronics in copper electroplating.
• The PEO block is crucial for ensuring the stability of the inhibition effect.
• Optimizing Pluronic suppressors requires balancing PPO-driven inhibition strength with PEO-driven stability.
• Hydrophilic-lipophilic balance (HLB) and PEO block length are valuable parameters for designing effective copolymer suppressors.