Mask aligner

What it does

A mask aligner copies a pattern from a photomask onto a wafer coated with photoresist. Under its microscope the operator aligns marks on the mask with marks on the wafer; the wafer is then pressed against the mask, or held a few tens of microns below it, and exposed to ultraviolet light.

Contact exposure gives the finest lines, around a micron; proximity exposure spares the mask and suits thick resists. Back-side alignment places a pattern on one face in register with features on the other, for crystals processed on both sides.

After exposure the resist is developed, and the pattern becomes a metal film by lift-off or an opening for wet etching. With the spin coater and the wet benches it completes our photolithography line for flat substrates; curved ones go to the robotic system.

What we use it for

• Patterned films on crystals

  Thin films on silicon and germanium crystals, shaped to the pattern an experiment needs.

• Masks for etching

  Resist masks that protect part of a crystal while wet etching shapes the rest.

Working with us

Bring your mask or your design: we can coat, expose and develop test wafers with you in our cleanroom.