Historical production of rigid PCB s

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Lindsay Thomas
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1 Historical production of rigid PCB s

2 The Printed Circuit Board (PCB)

3 The PCB What is a Printed Circuit Board? Green plastic thing with holes!! (green plastic syndrome) Platform for components Image with an electrical function But most of all

4 The PCB The PCB is always custom made. It is a bespoke item, it is only usable for a unique function which is pre- determined d by its design.and only produced d upon customer demand!! It is the first item needed for assembly purposes, and it is the only component that has value added to it during the assembly process.

determined d by its design.and only produced d upon customer demand!

5 The PCB A brief historical roadmap of PCB s 1903, First PCB-patent Single/Double sided d boards 1947 Double sided, plated thru 1960 Multilayer 1993 NCAB was founded (1986 in Malaysia) 1995 Micro via 2000 Embedded components Source IPC

Double sided, plated thru 1960 Multilayer 1993 NCAB was

6 The PCB How did the world appear directly prior to the first PCB patent? It was a world without: Cars. Aeroplanes, rockets or satellites. GPS navigation systems. Radio, Cinema, TV, Video, CD, Computer & Internet X-Ray, Laser, Penicillin & Losec. Mobile telephones, SMS or . Washing machines. Cash machines / Credit cards. Industrial robots. NCAB.

Radio, Cinema, TV, Video, CD, Computer & Internet X-Ray, Laser, Penicillin & Losec.

7 How to produce a (rigid) PCB

8 The PCB factory

9 Fabrication of a rigid PCB an overview

10 Application of photo-resist (etch resist) Core material Core material Laminating etch-resist Adding etch-resist

11 Inner layer imaging of photo resist (etch resist) using UV

12 DES - Develop Etching Stripping Develop Remove excess / unwanted Photo-resist Etched unwanted copper removed Stripped photo-resist fully removed.

13 AOI Automatic Optical Inspection Automatic Optical Inspection where the circuitry is scanned / checked. Brown oxide oxide layer added to assist with bonding. The inner layer core is now complete, this process may be repeated depending upon layer count

Brown oxide oxide layer added to assist with bonding.

14 Stack up / Bonding / Pressing Copper foil Pre-preg Inner core Pre-preg Inner core Copper foil Pre-preg

15 Stack up / Bonding / Pressing

16 Drilling, Elecroless copper & Outerlayer imaging Drilling Electroless copper Laminating of plating resist Exposure

17 Pattern plating Develop Remove unwanted photo-resist Pattern plating of copper Plating of etch-resist

18 SED - Strip, Etch, De-tin Stripping of photo-resist Etching of unwanted copper Tin removed & circuitry defined

19 Soldermask Soldermask applied to whole panel Artwork aligned. Black = no soldermask Imaging using UV light Develop away unwanted soldermask

20 Surface treatment Surface finish added to areas of no soldermask. Available options: HASL Hot Air Solder Levelling HASL ENIG ENEPIGG Immersion Tin Immersion Gold Immersion Silver OSP Refer to NCAB Group presentation titled PCB Surface Treatments for more details

ENEPIGG Immersion Tin Immersion Gold Immersion Silver OSP Refer

21 Contour routing or scoring / v-cut

22 Electrical test Checking for continuity using test probes on each side Detecting of open circuits Detecting of short circuits

23 Electrical test bed of nails PCB Probe fixture Test bed in test machine

24 Types of via holes for electrical interconnections

25 Types of via holes Through hole vias (traditional) Buried vias Blind vias Microvias, normally laser drilled.(micro via =<150 µ)

26 Buried via

27 Blind via

28 Micro via

29 Laser drilling of a micro via Profile cut Trepanned

30 Micro via in FR4

31 Stacked micro via holes Creates contact between multiple layers consuming the space of one via. Preferable to be copper filled. The technology allows one micro via to connect as deep as needed.

32 Copper filled micro via

33 Factory factors / differences

34 Fabrication of a rigid PCB So, now we understand how a printed circuit board is made... But how are the factories set up? Types of boards? Do we need different types of PCB factories?

35 Different setups of factories Different technologies will not all be covered in one single factory, quite often they will specialise in certain technologies: Single sided Double sided d Multilayer Flex / Flex-rigid HDI IMS HF Military / Automotive / Medicine (high demands)

36 Different setups of factories As with technologies, different volumes and lead times will necessitate different factories who can cope with such different demands: Prototypes Medium volumes High volumes Fast turnaround Asia vs. Europe

37 Different setups of factories So... it is very important to select the right combination of factory setup and match that to the type / design of the PCB, and also the demand. Get this wrong and concerns could include: The delivery time needed might not match the actual delivery. The factory may not truly have the technical competence to reliably make the board. The cost may be unnecessary high.

How to Build a Printed Circuit Board. Advanced Circuits Inc 2004

How to Build a Printed Circuit Board 1 This presentation is a work in progress. As methods and processes change it will be updated accordingly. It is intended only as an introduction to the production