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User Manual SIPLACE HS-50 5 Station extensions Software Version SR.50x.xx 01/2006 US Edition 5.5 Ceramic substrate centering 165 Fiducial st ructure 5 Recommendat ion 1 Fiducia l structu re Black resistiv e pas te as the…

5 Station extensions User Manual SIPLACE HS-50

5.5 Ceramic substrate centering Software Version SR.50x.xx 01/2006 US Edition

164

5.5.5.2 Fiducial mark recommendation for ceramic substrates

The contrast between the carrier package material and the circuit-board conductor layer is gener-

ally very small with ceramic substrates. The fiducials must therefore be selected with regard to

certain criteria concerning the fiducial shape and structure. Recommended fiducial shapes and

structures are given below.

Fiducial shape 5

We recommend a rectangle or square with an edge length of > 1 mm, and a clearance

of > 0.5 mm.

Fig. 5.5 - 3 Recommended fiducial shape

PLEASE NOTE

Single crosses are also suitable, but they take up more space. 5

0.5 mm

1.0 mm

User Manual SIPLACE HS-50 5 Station extensions

Software Version SR.50x.xx 01/2006 US Edition 5.5 Ceramic substrate centering

165

Fiducial structure 5

Recommendation 1

Fiducial structure Black resistive paste as the background, with conductive paste printed on it as

the fiducial.

Recommendation Background 0.75 mm larger than the fiducial on all sides.

Method of illumination Normal light

Advantage Good contrast, good sharpness;

Reference Circuit-board conductor layer

Assessment This combination gives the best results. Highly recommended.

Recommendation 2

Fiducial structure Fiducial made from circuit-board conductor material, e.g. 6119, and overprinted

with passivated glass 4330.

Method of illumination Oblique light

Advantage No additional steps required

Reference Circuit-board conductor layer

Assessment Fiducials are less sharp than for recommendation 1. Recommended.

Recommendation 3

Fiducial structure Fiducials made from circuit-board conductor layer against a free ceramic back-

ground.

Method of illumination Oblique or normal light (depending on the paste)

Advantage No additional steps required

Reference Circuit-board conductor layer

Note Fiducials are less sharp than for recommendation 2.

The fiducial image depends on the surrounding free surface. It may be neces-

sary to teach every circuit separately.

Assessment Recommended under certain conditions.

5 Station extensions User Manual SIPLACE HS-50

5.5 Ceramic substrate centering Software Version SR.50x.xx 01/2006 US Edition

166

5.5.6 Optical centering with the multicolor PCB camera

5.5.6.1 General

As an option, a multicolor PCB camera can be installed in place of the sub-gantry camera. The

multicolor PCB camera offers four different types of illumination. This greatly increases fiducial

recognition and thus the centering accuracy.

Fig. 5.5 - 4 Multicolor PCB camera

5.5.6.2 Types of illumination for the multicolor PCB camera

The following types of illumination can be selected on the multicolor PCB camera.

– Standard lighting

This mixture of white and infrared lighting can be used to detect a broad range of fiducials. The

image contrast can be improved by varying the illumination, thus optimizing the centering of

different fiducials.

– White lighting

This type of illumination is used for standard PCBs with tinned fiducials.

– Blue oblique lighting:

In most cases, this can be used to greatly improve the contrast with bright fiducials on a light