Multi-beam e-beam lithography uses multiple parallel electron beams writing simultaneously to overcome the fundamental throughput limitation of conventional single-beam electron-beam lithography. By writing with thousands to millions of beams in parallel, it aims to achieve throughput competitive with optical lithography.

The Single-Beam Problem

• Conventional e-beam lithography writes features one pixel at a time with a single focused electron beam. Resolution is superb (sub-5 nm), but throughput is extraordinarily slow.
• Writing a single wafer layer can take hours to days with a single beam — compared to seconds with optical lithography. This makes single-beam e-beam impractical for high-volume manufacturing.

Multi-Beam Solutions

• IMS Nanofabrication (MBMW): The leading multi-beam approach uses an array of 262,144 (512×512) individually controllable electron beamlets. Each beam is switched on/off by electrostatic blanking plates. This parallel writing multiplies throughput by orders of magnitude.
• Multi-Column: Multiple independent e-beam columns, each with its own beam and optics, writing different areas of the wafer simultaneously.

How Multi-Beam Writing Works

• A single electron source generates a broad beam.
• The beam passes through an aperture plate with thousands of holes, splitting it into individual beamlets.
• Each beamlet passes through its own blanking electrode for individual on/off control.
• All beamlets are focused onto the wafer through a common reduction lens system.
• The wafer stage moves continuously while the beamlets are modulated to write the pattern.

Applications

• Mask Writing: Multi-beam systems are already used in production for writing advanced photomasks — the master patterns for optical lithography. This is the primary commercial application today.
• Direct Write: Writing patterns directly on wafers without masks. Promising for low-volume production, prototyping, and mask-less lithography.
• Mask Repair: Precisely modifying defective regions of photomasks.

Current Status

• IMS's multi-beam mask writer is in production use at major mask shops for writing advanced EUV masks.
• Direct-write multi-beam for wafer production is still in development — throughput improvements are needed to compete with EUV for high-volume manufacturing.

Multi-beam e-beam lithography is transforming mask making for advanced nodes and represents a potential path to mask-less manufacturing for specialty and low-volume applications.