Semiconductor Leg Expiration — Molybdenum Substitution Timeline
WF6 tungsten CVD is being displaced at leading-edge fabs — the clock started February 2025
Key insight: This substitution does NOT eliminate tungsten semiconductor demand — it caps growth. Existing fabs running BiCS9, V9, and prior generations continue to require WF6 throughout this window. Only new capacity built from 2027 onward routes around tungsten. The window for WF6 disruption impact is real but finite.
Lam ALTUS Halo ships
First Mo ALD tool
Micron early customer
Kioxia BiCS10 eval
Kioxia BiCS10
MoO2Cl2 production
332-layer NAND
WF6 demand growth
flattens at
leading edge
Samsung V10 NAND
Mo word-line eval
Volume Mo adoption
across new capacity
Semiconductor leg
structurally capped
EXISTING FABS
WF6 Continues
BiCS9 / V9 / all prior
generations continue
WF6 CVD as-is
WF6 inventory
approaching depletion
price +70-90%
Existing fabs still
require WF6
No capex for switch
Disruption impact
on existing fabs
BiCS9/V9 still WF6
Gradual phase-out
as old capacity retired
Not a sudden cliff
Expected (high confidence)
Projected (lower confidence)
Investment implication: Do not underwrite the WF6 semiconductor disruption as a multi-year structural driver. The disruption window is approximately 12-24 months (H2 2026 to ~2028). The defense WHA path (no Mo substitute at required density) and carbide tooling path (no adequate Mo carbide at commercial scale) are the durable drivers.