Adhesion promoter for

next generation packaging needs

Promobond® AP2

Adhesion promoter for mold/PI material on Copper

Better adhesion of mold/ PI material to Copper

Due to better anchoring of polymer with needle structure

Increased reliability of next generation packages

Due to controlled dense oxide formation, which prevents further uncontrolled oxidation

Improved composite formation

To ensure good ductility

Adhesion promoter

In advanced packaging applications, finest RDL as well as pillar structures are surrounded by polymeric mold/PI materials to ensure state of the art performance. Promobond® AP2 is a promoter designed to increase the adhesion of standard molds such as PI to plated Cu structures and the formation of composite layers at their interface. Treatment with Promobond® AP2 hence leads to significantly improved mechanical properties and increased reliabilities of Cu RDL and pillar structures when exposed to changing temperatures.


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  • Pillar and RDL plating
  • Mold/PI material adhesion improvement after Cu plating
  • Applicable in wet bench and spray type tool

  • Controlled, self-limiting dense oxide formation protects from further uncontrolled oxidation
  • Needle structures allow Cu/polymer composite formation
  • Ensures good ductility of the mold/Cu combination
  • Minimal required exposure time
  • Excellent mechanical properties of Cu RDL and increased reliability
  • Possibility of batch processing ensures cost efficient processing

What inspires us

Why we developed Promobond ® AP2

Your challenge

State of the art heterogeneous integration in packaging processes requires the combination of a variety of different materials with different coefficients of thermal expansion (CTE). In a package, thermal expansion is mainly dominated by die and mold, which creates a high strain on thin RDL Cu lines. Temperature changes hence lead to increased stress due to different thermal expansion of the materials and thus to potential Cu RDL fractures. To minimize the risk of yield reduction and increase the reliability of the manufactured devices, outstanding mechanical properties of the Cu RDL structures are required. For pillars, the adhesion of the mold material to the Cu surface is crucial to avoid gap formation. A good ductility and adhesion of mold/PI to the Cu surface therefore has a significant influence on the overall performance and reliability.

Our solution

Promobond® AP2 is Atotech’s adhesion promoter for Cu structures under patent application. Due to the controlled, fast, and self-limiting formation of oxides, excellent adhesion improvement of PI/molds to plated copper structures is achieved. This leads to excellent mechanical properties, significantly increased reliabilities and hence minimized failure rates.

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