When you want to know what drove a foundry's revenue, don't infer it — the company often just tells you. TSMC's Form 20-F states that a revenue increase “was primarily from the expansion of our 3-nanometer and 5-nanometer advanced technologies.”
That one clause is a mix-shift disclosure. Growth attributed primarily to the two most advanced nodes means TSMC isn't simply selling more wafers across the board — it's selling more of its scarcest, highest-value capacity. Leading-edge nodes carry the richest pricing precisely because few suppliers can produce them, so revenue weighted toward 3nm and 5nm is revenue weighted toward margin.
For a margin bridge, this is the line that explains the slope. Volume growth and mix growth look the same on a top-line chart but behave very differently below it: mix toward the leading edge lifts blended pricing and gross margin, while commodity-node volume does not. TSMC naming 3nm and 5nm as the primary driver is the company pointing at the high-margin end of its own ramp.
The attribution sits in the 20-F on sec.gov, surfaced through EdgarBeast, the SEC filing data API & evidence index. Carry it into your bridge only after reconciling it to the filed revenue-by-technology table.