西门子SIPLACE S-27 HM用户手册.pdf - 第183页
User Manual SIPLAC E S-27 HM 7 Station extensions Software vers ion SR.503.xx 07/ 2003 US Edition 7.5 Ceramic substrate centering 183 7.5.4.2 Fiducial structur e 7 7 7 Recommendation 1 Fiducial struct ure Black r esistiv…
7 Station extensions User Manual SIPLACE S-27 HM
7.5 Ceramic substrate centering Software version SR.503.xx07/2003 US Edition
182
7.5.4 Fiducial shape recommendation for ceramic substrates
The contrast between the carrier package material and the circuit-board conductor layer is gen-
erally 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.
7.5.4.1 Fiducial shape
We recommend a rectangle or square with an edge length of > 1 mm, and a clearance of
>0.5mm.
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Fig. 7.5 - 2 Recommended fiducial shape
PLEASE NOTE
Single crosses are also suitable, but they take up more space. 7
0.5 mm
1.0 mm
User Manual SIPLACE S-27 HM 7 Station extensions
Software version SR.503.xx 07/2003 US Edition 7.5 Ceramic substrate centering
183
7.5.4.2 Fiducial structure
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Recommendation 1
Fiducial structure Black resistive paste as the background. 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
background.
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
necessary to teach every circuit separately.
Assessment Recommended under certain conditions.
7 Station extensions User Manual SIPLACE S-27 HM
7.5 Ceramic substrate centering Software version SR.503.xx07/2003 US Edition
184
7.5.5 Optical centering with the multi-color PCB camera
7.5.5.1 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 de-
tection and thus the centering accuracy.
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Fig. 7.5 - 3 Multi-color PCB camera
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7.5.5.2 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.