00192471-03.pdf - 第164页
5 Station extensions User Manual S IPLACE HS-50 5.5 Ceramic substrate centering Software Version SR.50x.xx 01/ 2006 US Edition 164 5.5.5.2 Fiducial mark recommendati on for ceramic substrates The contra st between the ca…
User Manual SIPLACE HS-50 5 Station extensions
Software Version SR.50x.xx 01/2006 US Edition 5.5 Ceramic substrate centering
163
5.5.5 Optical centering with oblique lighting
5.5.5.1 General
For optical centering, the special features of the ceramic substrate must be taken into account.
The contrast depends very much on the paste used for the adjustment structure, the clear area
surrounding the adjustment structure, and the type of illumination.
The oblique lighting unit is located on the front part of the sub-gantry camera.
Fig. 5.5 - 2 Oblique lighting unit for the sub-gantry camera
Oblique lighting may be switched on instead of the existing lighting (see table in Section 5.5.2 on
page 160
).
PLEASE NOTE
Oblique lighting can only be used on the “sub-gantry camera”. 5
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.