multi-beam e-beam

**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.