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6 1 From Optical MEMS to Micromechanical Photonics

Electron-beam

Exposed part

Resist
Substrate
Fig. 1.5. Electron beam lithography (EBL)in which focused high-energy electrons
are irradiated to the electron-sensitive resist
Syncrotron
radiation
Mask
PMMA resist
Metal substrate

Development

Ni deposition

Mold

Fig. 1.6. Lithographie galvanoformung abformung (LIGA)involves X-ray lithogra-
phy and electrodeposition processes

ratio (thickness-to-width ratio) can be fabricated by Lithographie galvanofor-
mung abformung (LIGA), illustrated in Fig. 1.6. LIGA involves X-ray lithog-
raphy, electrodeposition and moldingprocess [1.24]. The aspect ratio that can
be achieved usingLIGA exceeds 300. LIGA exhibits the followingcharacter-
istics:

1. high resolution
2. high aspect ratio
3. high throughput by mask and molding process
4. complicated mask production process.