Allegro/OrCAD Rigid Flex Design Creation Best Practices
_______________________________________________________________________
Learn more at Cadence Online Support - https://support.cadence.com Page 10
© 2016 Cadence Design Systems, Inc. All rights reserved worldwide.
There are three basic stackup definitions here, which are defined in Cross Section:
The first group of materials identified in the image as Primary Stackup represents the rigid zones of
the design.
The second stackup group, identified as Stackup 2, represents the flex zones of the design.
Stackup 3, represents a flex zone with a stiffener making the zone "inflexible".
In Cross Section Editor, perform the following tasks:
1. Define the Primary stackup definition.
By default, Cross Section Editor contains a single Dielectric layer and two copper layers. This is the
default Primary layer.
2. Add two more copper layers.
3. Add multiple dielectric layers as illustrated in the following figure:
Stackup
3
Stackup
2
Stackup
2
Primary
stackup
Primary stackup
Solder Mask (LPI)
.5 oz. Copper
Prepreg
Coverlay adhesive
Coverlay
Polyimide (core)
oz.
FR-4
Stiffener
(SS)
Stiffener Adhesive
FR-4
FR-4
Prepreg
Prepreg
Prepreg
.5 oz. Copper
.5 oz. Copper
.5 oz. Copper
.5 oz. Copper
Solder Mask (LPI)
Solder Mask (LPI)
Solder Mask (LPI)
Coverlay adhesive
.5 oz. Copper
Coverlay
FR-4
