Silicongate 1967 Step 20 Close Extension Canonical Legacy

# Close This Extension: Why This Process, Specifically, Became the Industry's Shared Starting Point

## 1. What This Extension Has Actually Established

Step 10 of this series' original run called this process canonical; this extension has spent ten steps making that claim specific and checkable rather than assertion alone: a named individual contribution (Faggin, Step 11) distinct from his later, different work elsewhere in this project; the exact deposition and process-sequencing detail (Steps 12-13) behind the self-alignment Steps 1-10 already argued for; two separately quantified benefits, stability and density (Steps 14-15), beyond the speed result Step 8 already measured; and a real, named adoption history (Steps 16-17) showing the process did not just exist but spread. That is a materially fuller account of "canonical" than the original ten steps alone could support.

## 2. Naming, Not Retelling, What Depends on This Process

This project's cmos_logic_1980s, hmos_1978, and bicmos_logic_1980s series (named in detail in Step 18 of this extension) all assume this process as their shared starting point, and this series remains, deliberately, the dedicated origin story for that process rather than a duplicate of any of their own content. One open thread -- the interconnect-scaling problem this series itself creates, named honestly in Step 19 -- is left open rather than forced to a successor that does not yet exist in this project's own content. That is the complete, honest state in which this extension closes.