Core – Base Material
The king size boards (36” X 48”, 42” X48”) are sheared in to the production required (standard) size. Pre-cut panels are also available
Before beginning of the inner layer processing, the inner layer cores are baked at a temp greater than glass transition temp.
This is done:
To relieve the stress To obtain mechanical stability of the panels
To remove the moisture content
The base material is chemically cleaned to remove oil, grease, finger prints, oxidation, anti-tarnish coating or any other contamination. The laminates are micro etched to increase the roughness of the surface, which aid bonding of DFPR
Lamination is a process of applying “Dry Film Photo Resist” (DFPR), a photosensitive material, on to the panels.
Core – Photo tool
The photo tools consist of master image of the circuit in the form of Opaque and Transparent areas.
After being hot roll laminated, the panel is placed in a UV printer frame, and a photo tool is positioned on the panel using tooling pins. The panels are then exposed to a high intensity UV light
Core Resist Exposed
The opaque (emulsion) portion on the photo tool blocks UV light, hence UV light passes only through transparent areas, to activate the DFPR.
The area of the dry film exposed to UV light undergo a chemical reaction called “Polymerization”.
The polymerized DFPR become impervious to chemical solution in the next step of the process developing
Core – Developing
Developing is the process of selectively removing unpolymerized Photo Resist. The polymerized photoresist acts as a etch resistant medium, protecting the required copper in the next step of the process etching.
Core – Etching
The etching process serves to remove copper which is not protected from etchant attack by an etch resist mask, thus creating a circuitry pattern.
Polymerized Photo resist, which is no more required, is stripped off in this process.
Post Etch Punch
At Post Etch Punch (PEP), the 4 registration slots (2 additional slots for AOI) are punched. These slots are used for lay up of Multi-layer panels and for mounting in Drilling.
Automatic Optical Inspection (AOI)
At Automatic Optical Inspection (AOI), the image on the panels is compared with the CAM data and checked for opens, shorts and line width variations.
Open- Absence of copper in the required area, which leads to electrical discontinuity
Short – Presence of copper in the un wanted area, which leads to electrical interconnection between isolated circuit pattern
Cerra Systems Printed Circuit Board Fabrication capabilities support high-frequency PCB, High-temperature Boards, Thick PCB, ultra-thin PCB, heavy copper PCB, Metal Core PCB, HDI boards with Blind Vias, Buried Vias, Micro Vias, Embedded passives, bonded heat sink, Impedance Control, Depth control drilling, Back drilling, Edge Plated PCB, Bump Pads, cavity with ledge, Via on pad and stacked micro-Via technology.
CerraSystems – http://cerrasystems.com
HDI PCB , Rigid Flex PCB, RF PCB
Electronics Manufacturing Partners:
Argus Systems (AESPL) – www.sysargus.com