Ralf Schwartz, CEO, Peters

What's Ahead for 2025

The drive towards high density, ultra-high density and alternative substrates, including glass, will be transformative for wire interconnection manufacturing. For under bump metallization, spacing densities will preclude thick electroless nickel deposit stacks, including ENIG/ENEPIG.

Fortunately, alternative nickel-free Final Finish Deposit Stacks have proven effective. These include EPIG and EPAG (Electroless Palladium Immersion Gold and Autocatalytic Gold, respectively), also DIG (Direct Immersion Gold on copper).

Deposit reliability will be determined by the electroless palladium diffusion layer, which requires low porosity, and therefore good initiation, and tight grain structure.

The competitive evolution from mSAP to full semi-additive SAP will also command headlines. Once PWB manufacturers are comfortable with modified SAP (mSAP), transition to full semi-additive SAP will occur.

Copper surface topography will grow in importance. As line geometries move below 25 microinches, specialty etchants combined with organic adhesion promoters will be needed.

Three processes for low profile topography will become commonplace: a copper micro-etchant that develops a unique roughened surface with high physical adhesion to many resins; a process that optimizes copper/resin adhesion by coupling an ultra-low etched, unique roughened surface plus organic film layer, and a super-fine copper surface roughener with an organic adhesion promoter, producing an ultra-smooth surface, and lowest signal insertion loss.