Optimize the Interconnect:
Where Wet Processes Decide What’s Possible

You can drill the most perfectly formed via in the world.

If the wet process doesn’t understand it, the interconnect still fails.

In Episode 5 of On the Line with MKS, Patrick Brooks—Senior Director for Electronic Systems at MKS Atotech—brings Optimize the Interconnect (OTI squarely into production reality. After decades spent in wet processing, Patrick frames OTI not as an abstract optimization effort, but as something far more tangible: the difference between precision that survives manufacturing and precision that doesn’t.

Episode 5 of the OTI Story

Author: Ryan Wagner
Released: August 21, 2026

Wet Processes Are Not “After the Fact”

A common misconception in PCB manufacturing is that wet chemistry exists to clean up what upstream processes leave behind. Patrick challenges that idea immediately.

Under OTI, wet processes are not reactive—they are foundational.

Surface treatments applied before laser drilling determine how energy is absorbed, reflected, or scattered. Cleanup processes applied after drilling define whether residues are removed cleanly or redistributed into future failure sites. Everything in between depends on fluid dynamics, uniformity, and timing.

OTI forces wet processes to be seen not as steps, but as interfaces.

The Bond Film Insight: Consistency Enables Precision

One of the most important concepts Patrick introduces is the role of bond film treatments—not as a new process step, but as a way to make existing processes predictable.

When laser drilling targets a copper surface, it depends on consistency:

  • Reflectivity
  • Surface morphology
  • Absorption behavior
  • Uniformity across the entire panel

Bond film treatments reduce variability across these dimensions. The result is a surface that behaves the same way everywhere—allowing laser parameters to be programmed accurately instead of conservatively.

In OTI terms, this is a recurring pattern: predictability unlocks performance.

Accuracy Is a Systems Outcome

Patrick emphasizes something that only comes from decades on the factory floor: precision doesn’t belong to any single tool.

Laser accuracy depends on surface chemistry. Cleaning effectiveness depends on via geometry. Plating reliability depends on both.

Wet processing must therefore be robust and precise—capable of maintaining tight tolerance without becoming fragile. This balance shows up in everything from flow design to transport systems, where fluid dynamics determine whether chemistry reaches where it needs to go.

OTI isn’t about tightening process windows everywhere. It’s about coordinating them intelligently.

Simpler Than You Think—and That’s the Point

One of the more counterintuitive themes in Episode 5 is that laser‑based via formation can actually simplify downstream cleanup compared to traditional mechanical drilling.

Mechanical drills introduce burrs, smear, tool-wear variability, and debris that require complex post-processing. Laser drilling, when paired with properly designed wet processes, produces cleaner, more consistent features that are easier to prepare for plating.

OTI reframes this as an opportunity: better upstream control makes downstream processes simpler, not more complicated.

Transport, Timing, and the Cost of Delay

Patrick introduces the idea of transportation within wet processes—not logistics, but how panels move through chemistry in time and space.

When residues dry unintentionally, oxidation risks increase. When solution exchange is uneven, interfaces become inconsistent. Small timing mismatches accumulate into reliability threats.

OTI treats transport as a design variable. Minimizing dry steps, managing transitions, and maintaining wet‑to‑wet flow improve interface quality without adding process complexity.

Physics Still Runs the Line

At one point, the conversation returns—as it often does in this series—to physics.

Fluid dynamics governs how chemicals reach microvias. Surface tension defines whether small features are fully wetted. Energy transfer controls whether residues detach cleanly.In this environment, “good enough” process control is no longer good enough.

Patrick is clear: OTI doesn’t replace wet process fundamentals—it makes them more important. What changes is the feedback loop. Wet process design now reflects laser behavior, just as laser recipes reflect chemical realities.

Wet Processes as Enablers, Not Constraints

By the end of Episode 5, the role of wet processing under OTI is unmistakable.

Wet processes are no longer the point where ambition gets scaled back to something manufacturable. They are the mechanism that allows ambition to survive production.

When surface preparation, cleaning, and metallization are designed together with via formation, the interconnect becomes resilient—not just precise.

And that sets the stage for the final chapter of the OTI story.

🎧 Listen to the production-line perspective

Next in the series: What OTI Means for the Future of Manufacturing (Episode 6)