Projects — KOSL

Active

Current projects

Phase 1 — Active

KOSL Albu

Egg white photoresist for home semiconductor fabrication

Lithography process using egg white albumen as photoresist with riboflavin (vitamin B2) as a 450nm photosensitizer. 5W laser diode on a CNC 3018 platform. Water-based development.

Currently in Phase 1: validating photoresist patterning at 100μm feature size on glass substrates. Riboflavin-mediated singlet oxygen crosslinks the ovalbumin protein, creating water-insoluble regions.

100μm target $525 setup 450nm laser Water develop

Planned

KOSL Machine 3

Automated maskless direct-write lithography system

Desktop lithography system with DLP maskless projection, machine vision alignment, and automated wafer handling. 10μm target resolution. Pending Albu Phase 2 completion.

Serves as the core platform for the KOSL 10MT5000 Auto product — a turnkey desktop semiconductor fab with HEPA enclosure.

10μm target Machine vision DLP projection

Research

Albumen photoresist science

The chemistry behind KOSL's egg white lithography process, developed by Lev Kropp.

Riboflavin-sensitized crosslinking

Ovalbumin (~62% of egg white protein) undergoes photocrosslinking when exposed to 450nm light in the presence of riboflavin. The riboflavin acts as a Type II photosensitizer — it absorbs blue light (molar absorptivity ~12,500 M^-1cm^-1 at 445nm), undergoes intersystem crossing to a triplet state (quantum yield ~0.67), and transfers energy to dissolved O₂ to produce singlet oxygen.

The singlet oxygen oxidizes amino acid side chains (His, Trp, Tyr, Met, Cys), creating covalent crosslinks that render the exposed protein insoluble in water. A 5W laser focused to a 100μm spot delivers ~64 kW/cm² — roughly 8 million times the power density of the original UV flood exposure described in the literature (Jiang et al. 2017).

Dual-function material

Crosslinked ovalbumin also functions as a gate dielectric with a dielectric constant of k ≈ 5–6 (higher than SiO₂ at 3.9), breakdown field of ~2–4 MV/cm, and surface roughness of ~5nm RMS. The same egg white film that patterns features also serves as the gate insulator in finished transistors.

Positive-tone patterning is also possible: adding glycerol at a 10:1 ratio suppresses aggregation and promotes chain fragmentation under exposure, making exposed regions water-soluble instead. This requires a two-step exposure (low-intensity pre-cure + high-intensity patterned exposure).

$0.004

per mL (albumen)

$1.49

per mL (PMMA)

Roadmap

Albu development phases

From photoresist validation through first transistors to a fabricated CPU.

Phase 1 — Current

Photoresist Validation

Validate egg white photoresist at 450nm using CNC laser and optical microscope. Success criterion: microscope-verified 100μm patterns on glass, developed in water.

$525 setup CNC 3018 + laser

Phase 2

First Transistors

First working transistors: ZnO TFTs on glass, Schottky-barrier MOSFETs, laser-doped Si MOSFETs, Cu2O p-type TFTs. Culminating in a 5-stage ring oscillator (10 transistors).

ZnO TFT Si MOSFET Ring oscillator

Phase 2.5

Automated Lithography Upgrade

Transition from CNC laser to DLP maskless projection lithography. Semi-automated spin coating and development. Basis for the KOSL 50MT500 Auto product.

50μm features DLP projection

Phase 3

Full Automated Fab Line

Complete end-to-end automated fabrication. Precision stages, HEPA enclosure, machine vision alignment. 10 engineering sub-phases. Basis for the KOSL 10MT5000 Auto.

10μm features ~5,000 transistors

Phase 4

First CPU

Fabricate a working CPU: either a custom 4-bit "Albu-4" (~910 transistors) or a SERV RISC-V core (~4,500 transistors), depending on Phase 3 yield data.

4-bit or RISC-V Up to 4,500 transistors

Future

DUV Stepper

Schwarzschild reflective objective DUV stepper with surplus KrF excimer laser. 500nm resolution — Pentium-class density, millions of transistors per die.

500nm features Millions of transistors