✦ The Back-End Beachhead: XT:260Narrow moat

For forty years ASML sold only to the front-end of chipmaking — the fabs that print transistors. The TWINSCAN XT:260, delivered for the first time alongside its third-quarter 2025 results, is the company's first machine built for the back end: a lithography scanner for advanced packaging, patterning the redistribution layers and interposers that stitch chiplets and memory stacks into AI processors, at roughly four times the throughput of the tools packaging houses use today¹. The timing is not subtle. CoWoS-class packaging is the AI supply chain's tightest bottleneck, interconnect has replaced the transistor as the binding constraint on AI hardware, and the packaging step suddenly justifies front-end-grade precision.

Strategically the beachhead can widen: ASML is reported to be studying hybrid-bonding equipment as a follow-on² — the step that would put it in direct contention for the whole advanced-packaging toolchain. The bet's charm is its asymmetry: the back end is a market ASML has never earned a euro in, so every unit is incremental, and its brand arrives with front-end authority no packaging-tool incumbent can match.

It is still a beachhead, not a franchise. Packaging lithography has entrenched suppliers, coarser tolerances, and price expectations far below ASML's habits. Watch XT:260 unit shipments and named packaging-house customers through 2027, and watch whether the hybrid-bonding study becomes a product. A monopolist entering a competitive market is a rare experiment: it tests whether the aura travels.