Using the Speedstack HDI Navigator to document pcb stackup with coated and uncoated areas

Question:
Is it possible to model a pcb stackup where some areas are coated with resist and other areas deliberately left uncoated?
– Speedstack HDI customer

Answer:
Very easily – with the Speedstack HDI Navigator or see AP552 if using Speedstack PCB.

Speedstack Navigator

This note discusses how the Speedstack HDI Navigator can document a PCB stackup where the board includes areas that are coated with photoresist and surface traces that remain exposed.

First, consider each finished sub-stack in Speedstack HDI:

Uncoated stack

Coated stack

Start by creating the uncoated pcb stackup (the Master stack) in the Stack Editor, then press F4 to open the Speedstack HDI Navigator:

Uncoated stack area

This "Master" stack represents the uncoated area; right click the Navigator and use the Addstack command to add a copy of the Master and name it "Coated". Click the new stack and return to the Stack Editor to add the photoresist and ident layers – the Navigator should display both areas as separate stacks (below).

Uncoated and coated areas in Speedstack HDI Navigator

Including controlled impedance structures

This example creates controlled impedance structures in both coated and uncoated areas: the uncoated areas use Surface Microstrip structures and in the coated areas Coated Microstrip structures, shown in Speedstack HDI's controlled impedance tab pane below.