Cadence Online Support has this Rapid Adoption Kit (RAK) on Rigid-Flex in Allegro PCB Editor 17.2 that introduces a flow to define unique stackups by physical zone. The Cross Section Editor in 17.2 has been enhanced to support multiple stackup definitions including support for mask and coating layers. The primary driver for this enhancement is Rigid- Flex applications where it’s common to have different fabrics across the final PCB product. Benefits will also be realized for customers designing standard Rigid PCBs. Soldermask and Solderpaste and their thicknesses can be added above/below the surface layers. Rigid PCBs may also require inlay material zones for RF/Analog circuits.
This RAK covers …
Adding Non-Conductor Layers to Cross Section
Multiple Stackup Entry
IPC2581 Layer Functions
Adding/Editing Physical Zones in the PCB Editor
Rigid-flex technology lets us create smaller PCBs than ever before. Watch the video on Serious tools for advanced rigid-flex
Cross Section Support of Non-Conductor Layers
The PCB Editor Database represents non-conductor layers as “Mask” or “Dielectric” although they may serve different purposes like coating or plating areas. To add a mask layer above layer Top, select the Top cell in the Cross Section grid then use the RMB to access the “Add Layers” command as shown in the graphic below.
The new Surface Finishes Class supports the following subclasses …
Multi-Cross Section Support
The Cross Section Editor has been enhanced to support multiple stackups, each capable of supporting conductor and non- conductor layers such as Soldermask and Coverlay. The Cross Section Editor provides total thicknesses for each stackup in terms of accumulated conductor layers as well as a mask layer option.
Multi-Stackup Grid
Layer Functions (IPC2581)
The Cross Section Editor now supports IPC2581 defined Layer Functions. These user selected Layer functions are defined as attributes in the IPC-2581 stack-up layer definition for fabrication instructions at the manufacturing level. Customers utilizing the 2581 standard for data transfer may want to consider these options. The diagram below reveals the full set of layer function options.
Dielectric layer types support the following options …
Physical Zones
Zones are physical areas in the design that map to one of the available stackups in the cross section editor. Zones are added using the standard add shape or add rectangle commands found in the Setup – Zones menu. Mapping a stackup to a Zone may occur at the creation of the Zone, or assigned through the Zone Manager after the Zone is created. Constraint Regions and Rooms may also be assigned to Zones at creation or through the Zone Manager.
When adding a Zone, you can loosely define the boundary during the creation command as it will snap to the design outline geometry upon completing the command. In the left figure below, a zone boundary is extended beyond the actual design outline. It eventually snaps to the actual design outline when the add shape command is completed.
Inter Layer Design Rule Checks
This RAK also explores Inter Layer checks that provide a new tier of checking of mask to mask and mask to other geometry types providing the user with problem detection earlier in the design to manufacturing cycle.
In typical rigid-flex designs, various stackup definitions are assigned into different zones where the top or bottom level might differ zone to zone. In traditional workarounds, the package symbols require special attention to padstack definitions, special “flex” symbols, and so on, or use the embedded component process to place these symbols onto the correct layer for not only artwork purposes but for documentation as well. You may refer the document on Dynamic Zone Placement in Allegro PCB Editor 17.2 here. This reviews the PCB Editor's awareness of varying top surface layers in a multi-zone rigid-flex design during placement.
Click here for the Rapid Adoption Kit and for the detailed step-by-step procedures on the Rigid-Flex functionality, as well as various other aspects that are not covered in this blog.
Note: The above link can only be accessed by Cadence customers who have valid login ID for https://support.cadence.com
Related Links
Learning Advanced Flex and Rigid-Flex Design Support in Allegro 17.2-2016
Why Move Up to Allegro 17.2-2016? Advanced Flex and Rigid-Flex Design Support (Reason 1 of 10)
Cadence Allegro Rigid-Flex Overview on Cadence.com
Ensuring Reliable Products with New Rigid-Flex Design Rules