Page 206 - Sami Franssila Introduction to Microfabrication

Moulding and Stamping 185

Oxide

Polysilicon
(a)

Cu
(b)

Anchor

Tether
(c)

Solder bump

Target die
(d)

(e)

Figure 18.3 Diamond microstructures made with silicon (f)
wafer disposable moulds. Reproduced from Bj¨ orkman, H.
et al. (1999), by permission of Elsevier
Figure 18.4 Polysilicon moulding in HexSil process: (a)
Deep reactive ion etching (DRIE) of trenches; CVD release
oxide, LPCVD polysilicon structural layer deposition; (b)
approach would be to deposit a thin metal layer on top of poly patterning and metallization; (c) oxide pre-release etch;
a device material and then use electroplating to deposit (d) alignment to carrier wafer bumps; (e) attachment to
a thick (>100 µm) backing layer. carrier solder bumps and (f) final release etch. Repro-
Heavy boron doping forms the basis of dissolved duced from Horsley, D.A. et al. (1998), by permission
wafer process. The p ++ -doped regions form the structural of IEEE