Automated Design for Micromachining

Suspension, Crab


A suspension is like a spring, designed to be compliant. However, they are also designed to be stiff in the perpendicular direction.

Layout of a crab suspension.

Figure 1: Layout of a crab suspension.

Model 1: Model of a crab suspension.


Nothing yet.


Any parameter may be modified, if necessary, to meet design rules. Typically, this involves increasing parameters that specify distances, so that minimum line width and minimum line spacing rules will not be violated. This has been extended to the convention of specifying a zero for some parameters to obtain an instance of the minimum size.

In addition to the parameters listed below, several technology parameters also influence the implementation of parameterized cells. This data must be present in the technology library.

Table 1: Parameters for the 'suspension_crab' parameterized cell.
Name Description Range Units P1 P2
length The length of the compliant beams. [0,∞) um + +
spacing The distance between the compliant beams. [0,∞) um + +
shuttle_length The length of the shuttle, which is the centre piece connecting all of the compliant beams. [0,∞) um + +
shuttle_width The width of the shuttle. If too small, the shuttle width will be increased to include dimples and the necessary enclosure rules. [0,∞) um + +
truss_length The length of the trusses, which are the segments perpendicular to the compliant beams that connect the beams to the anchors. [0,∞) um + +
truss_width The width of the trusses. [0,∞) um + +
yoke_length The length of the yoke, which are the two regions at the end of the shuttle. The yoke can be specified wider then the shuttle width to ease connection of the shuttle to other structures. [0,∞) um + +
yoke_width The width of the yoke. [0,∞) um + +
anchor_width The parameter is used to determine the minimum feature size of the anchors. It is automatically increased if smaller then the minimum width specified in the technology file. The main use of this parameter is to create large anchors for structural support or rigidity if required. [0,∞) um + +
include_poly0 If true, a POLY0 ground plane will be included in the cell. The POLY0 ground plane can eliminate most electrostatic attraction between the suspension and the substrate bulk. true/false - + +


The documentation for this parameterized cell does not contain any references.