PCB Manufacturing Process

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1．Pre-Production Engineering
2．Warehouse and Sheet Cutting
3．Inner Layer
4．Inner layers Etching
5．Inner Layer online AOI
6．Lay-up and Lamination
7．Mechanical Holes Drilling
8．Electroless Copper Deposition
9．Outer Layer
10．Copper Plating
11．Outer Layer Etching
12．Outer Layer AOI
13．Soldermask
14．Silkscreen
15．Surface Finishing(HASL LF, ENIG, Goldfingers etc)
16．Forming
17．E-test
18．FQC
19．Packaging
20．Delivery
21．After-Sales Service

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Details of every PCB Manufacturing Process

Production Process 1: Pre-engineering| Multi-layer HDI PCB Manufacturing Process

All pcb orders need to go through the engineering department before being scheduled for production.

What the engineering department does to ensure the smooth production?

A. Gerber files Review

After customers upload the Gerber files, the engineering department will first pre-review them. The contents reviewed generally include:
01) Whether the design files are complete.
① A complete PCB files should includes:
● Board outline ● Bottom copper ● Bottom silkscreen ● Bottom solder mask ● Fab drawing ● Inner layers ● NC drill ● Top copper ● Top silkscreen ● Top solder mask
② Clear and complete PCB requirements information(in gerber files or in separate files are all ok for us)
●  Layers ●  Material, TG value, TD value...
●  2 sides or single side need soldermask/silkscreen, what the soldermask/silkscreen color each side, how thickness the soldermask should be
●  Hole copper thickness ●  Quality standard request: IPC Class II or IPC Class III ●  Hole size or outline tolerance ●  Stack up ●  Others
02)Other issues, such as whether the circuit design is reasonable; whether there is any requirement beyond our capability.

B. BOM Files Review
If you want us assembly PCB boards for you too, then full files:Gerber Files+BOM File+Centroid File（other names maybe:aka Insertion, Pick-N-Place, or XY Data）should all included and provided to us when you order.
Click here to check Template-for-PCBA-Quotation

① Gerber Files, Please include all the layers files (copper, soldermask, silkscreen, solder paste, drill, outline).
② BOM file should clearly and full description of every kind of component, need at least below items:
●Manufacturer Part Number ●Manufacturer or Brand ●Specific description of components parameters and specification, including such as voltage, resistance, capacitance etc
●Location Number according to PCB silkscreen file ●Quantity

③ Centroid File, also known as pick and place file. It should include component locations, rotations and reference designators.

C.Deal with Gerber Files
When making sure the files are complete and basically ok, engineers start to make WF and send out EQ to communicate with customers.
1)(Engineering Question) EQ Communication, Working File(WF) and waiting for customer confirmation if customer request
WF Making: The information in the Gerber Files can’t be directly input to the corresponding machines for various processing. WF is then used to make compensation,optimization and panelization etc works to gerber files customers designed according to our factory actual production equipment, processes and technology. Such as in gerber file, customer request finished hole size 1.0mm, when making working file, our engineers will enlarge to 1.1mm. Using 1.1mm drill bit, adding copper plated, the finished hole size fits into 1.0mm; such as panelization, in order to fit equipment actual size, we have to panelize smaller size PCB in customer gerber files to bigger size, and add aided tooling edges and tooling holes for alignment and fixed onto equipment during production.

EQ communication: Engineers will read the Gerber files in details, they will send an EQ to the customer if there is any doubtful point. For example, if the laminate structure provided by the customer is asymmetric which may lead to board wrap and affect the assembly quality, then they will suggest the client to modify it into a symmetrical one.
Click here to check Common PCB EQ Examples

If customer need to confirm WF before production, we will send WF for customer’s confirmation and feedback, or we will begin PCB production.

2)Manufacturing Instruction(MI) Preparing, Production Drawing and Process Card
Each PCB order is prepared with a complete MI, which contains detailed instructions for each process from board cutting to packaging.
In addition to the MI, a production drawing and the process card also assist PCB production together. The production drawing is a special instruction for the important contents of the design files, include external dimensions drilling requirements, circuits, soldermask, silkscreen, etc. Process cards are mainly used to track the warehousing receipt, quantity and acceptance of each production process to endure that each step is in order and can be accurately traced in case of problems.
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Production Process 2: Warehouse and Sheet Cutting

PCB production starts with a large piece of sheet material. Due to the limitations of PCB production equipment and manufacturing capabilities, the factory has requirements for its minimum and maximum processing size. Therefore, under the guidance of manufacture instruction (MI), the base material of PCB-CCL(Copper Clad Laminate ) needs to be cut into the processing size by automatic cutting machine before production.

CCL we just use top brand materials:such as KB, Shengyi, Nanya, Rogers, Boyu...(with low/middle/high TG selections)

Base Material-CCL
Base Material-CCL

Production Process 3: Inner Layer

1)Laser sensitive film lamination

One layer of laser sensitive film is laminated to the CCL copper surfaces by heat and pressure.

3)Development

Development is to spray the inner layers horizontally with a Sodium Carbonate solution to remove the unexposed sensitive film areas, the areas which has been laser developed will be left.

The copper under developed film are the right circuit pattern we need. Development is the preparation work for subsequent etching process, development removes the film on unwanted copper area, unwanted copper will be exposed in etching solution to get rid off, finally we get the right inner layer circuit pattern we need.

2)LDI(Laser Direct Imaging) to exposure circuit pattern

LDI is that directly laser expose to get circuit pattern, no need film, this step of the process is performed in a clean room.

LDI directly laser sensitive film to get circuit image, no need film, reduce film cost, eliminate film alignment error, to get high-accuracy circuit images(min trace width/spacing just 1mil/1mil), widely used to manufacture high-density and high-accuracy multi-layers PCB, buried&blinded vias, such as IC support plate, flexible PCB, HDI PCB,Flex-Rigid PCB etc; totally automatically operation:such as automatically load PCB boards, mechanical arms grabbing boards, 2 sides circuit same time imaging(no need to change top side to bottom and wait exposure compared with traditional exposure machines), shorten production lead time and can effectively control bad imaging quality problems such as lines too thin, micro-short, unclean etching; Adding online AOI optical inspection, eliminate all possible hidden quality problems.

LDI exposure compared with film exposure get higher accurate and aligned imaging:

Integrated automatic LDI Production Line / After LDI circuit exposure, get clear circuit patterns as above picture

3)Development

Development is to spray the inner layers horizontally with a Sodium Carbonate solution to remove the unexposed sensitive film areas, the areas which has been laser developed will be left.

Developed PCB

Production Process 4: Inner layers Etching

Inner layers Etching is to remove the unwanted copper where not protected by film area from the panel by etching solution.

1)To etch the unwanted copper where not protected by film area from the panel by etching solution. So the film on wanted copper is to resist the etching solution to protect under wanted copper.

2)Get rid of the film on wanted copper pattern to get the right inner layer circuit pattern we need.

Circuit Pattern Etching Production Line

Production Process 5: Inner Layer online AOI

AOI: Automated Optical Inspection. When PCB boards going into online AOI machine, AOI will automatically scan circuit pattern to get images and compare with standard “digital images”, mark the differences between them and transmit to VRS, to confirm whether differences are false O/S points or true O/S points.

AOI Inspection can check and find inner layers images quality problems quickly, such as short, open, breaking lines. Inner layer AOI inspection can effectively prevent following production processes continue to cause unnecessary time delay and cost waste if inner layer images are found with problems, which has been judged should be scrapped and remake.

Online AOI Machine

Production Process 6: Lay-up and Lamination

First step is Lay-up: Lay up copper foil, PP and base material together according to manufacturing instructions standards for lamination. In order to ensure the alignment accuracy between layers, boards should be nailed. There are 4 modes of nailing boards, eyelet, hot-melt, eyelet+hot-melt and Pin-Lam

Second step is Lamination: Under the conditions of high temperature(375 fahrenheit degrees), high pressure(275 to 400 psi) and vacuum, after thermal polymerization of polymer materials, the inner base material, copper foil and PP are laid up according to the set sequence.

Lay-up
Lamination Machine

Production Process 7: Mechanical Holes Drilling

We now have to drill the holes that will subsequently create electrical connections within inner and outer layers. Under the control of program files, using CNC drilling machines to drill holes on PCB which connect the electrical property between each layers.

Drilled Holes
Drilling House
6 drills Drilling Machines

Production Process 8: Electroless Copper Deposition

property between each layers.

Desmear+PTH+VCP 3 connecting Production Lines

The first step in the plating process is the chemical deposition of a very thin layer of copper(typically 5-8um) on the hole walls.

1)Desmear is to use KMNO4 high oxidation to get rid of drilling residues in hole wall, and micro-etch the hole wall material to form honeycomb to strength adhesive force with Pd when following PHT process, and to strength adhesive force between hole wall base material and deposited copper to prevent hole wall copper separation.

2)PTH

3)VCP production lines provides a very thin deposit of copper(typically 5 to 8 um) that covers the hole wall and the complete panel. we now have electrical continuity between layers and through the holes.

VCP(vertical continuous plating) production line has excellent capability in uniform distribution of copper plating , vias plug and covering, plating stability. VCP with much lower waste gas emissions, can be easily operated and maintained, less space occupied, totally answer for modern PCB equipment design concept which request energy saving and environmental protection, can be widely used to panel plating, surface copper thicken plating and high aspect ratio PCB plating support equipment.

Production Process 9: Online LDI Outer Layer Image

Outer Layer circuit pattern is similar with inner layer, different place is to plate a layer of Sn to protect circuit copper when outer layer etching process.

Production Process 10: Copper Plating

The second step in the plating process is copper thicken plating, this step is to thicken circuit and hole wall copper to customer requested thickness. If IPC class II, our PCB hole copper min 20um, if IPC class III, our PCB hole copper min 25um.

1)Copper Plating: Under the action of direct current, the copper loses electrons and turns into Cu2+ and dissolved in the solution. The Cu2+ acquires electrons and deposits to a copper plating layer, for thickening the circuit and hole wall copper to customer requested thickness.

2) Tin Plating: Electroplate a layer of tin on the exposed circuit surface after copper plating, to protect the required circuit copper from being etched in etching process.

Production Process 11: Outer Layer Etching

This is normally a three step process.

1)The first step is to remove the laser sensitive film.

2)The second step is to etch away the exposed/unwanted copper whilst the tin deposit acts an etching resist to protect the copper we need.

3)The third and final step is to chemically remove the tin deposit leaving the circuit copper.

Etching Production Line

Production Process 12: Outer Layer AOI

Just like with inner layer AOI the imaged and etched panel is scanned to make sure that the circuitry meets design and that it is free from defects. Again no repair of open circuits are allowed under demands.

AOI Inspection after Etching
AOI Inspection after Etching

Production Process 13: Soldermask

Solder mask is applied to PCB boards to protect the copper surface that will not be protected by soldering in the assembly process and to prevent solder shorts during assembly.

1)Soldermask Print
Totally automatic soldermask print, operated in 10 thousand class cleaning-room. The working panel is automatically printed on both sides with an epoxy solder mask oil about 15-25 um thick.

10 thousand class cleaning-room, Automatic soldermask Print Production Line

Automatic soldermask Print Production Line(Details)
2)Soldermask Exposure
Using a UV light and a soldermask film, the solder mask is hardened on the area where we want the solder mask to remain.

10 thousand class cleaning-room, Automatic soldermask exposure

A soldermask film

3)Soldermask Development
Soldermask Development is to remove the unexposed area soldermask oil by development solution, so that developed soldermask can be exposed out to bake in subsequent baking process.
4)Soldermask Baking
More than 80 minutes baking to make sure soldermask uniformity and adhesion, to comprehensively solve annular-ring turned red and copper exposure risk.

Soldermask Baking Tunnel Oven

Production Process 14: Silkscreen

New silkscreen printer can effectively avoid impurities, unclear, shifted silkscreen etc silkscreen problems compared with manual silkscreen printing operation.

Silkscreen Automatic Printing Machine
Silkscreen Automatic Printer

Production Process 15: Surface Finishing(ENIG, HASL/HASL LF, OSP, Immersion Gold/Ag, Hard gold plated...)

Various finishes are then applied to the exposed copper areas that are not covered by solder mask. This finish protects the copper until the components are assembled and soldered to the printed circuit boards. Several surface finishes are available, such as ENIG, HASL/HASL LF, OSP, Immersion Ag, Hard gold plated...

ENIG Production Line
OSP Production Line
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Production Process 16: Forming

This process is to cut production panels into specific smaller size and shape according to customer design in gerber files. There are 3 main profiling method-V-cut, CNC routing or punching. All dimensions will measured against the customer supplied drawing to ensure the panel dimensions are all conforming to tolerance standard.

Forming Room
6-drill CNC Routing Machine
V-CUT Machine

Production Process 17: E-test

Used for checking the integrity of the tracks and the through hole interconnections – checking to ensure there are no open circuits or no short circuits on the finished board. There are two test methods, flying probe for smaller volumes and fixture based for volumes.We electrically test every multilayer PCB against the original board data. Using a flying probe tester we check each net to ensure that it is complete (no open circuits) and does not short to any other net.

FQC House
Automatic Inspection Machine
Flying Probe Testing Mahine

Production Process 18: FQC

In the last step of the process a team of sharp-eyed inspectors give each PCB a final careful check-over.Visual checking the PCB against acceptance criteria as IPC600 reference. Using manual visual inspection and AVI – compares PCB to gerber and has a faster checking speed that human eyes, but still requires human verification. All orders are also subjected to a full inspection including dimensional, solderability, etc.

AVI
FQC Inspection

Production Process 19: Packaging

We know that state-of-the-art equipment are what make us the world’s leading manufacturer of PCB prototyping and low-volume production. Here are some of the machines and equipment. As we are constantly improving our machines to guarantee good quality, please check back for more.

Automatic Paper Inserting Machine (Insert paper between PCBs to avoid possible scratch)

Production Process 20: Delivery

UPS, DHL, Fedex, TNT, Air Fright, by sea, by forwarder, all shipping ways are acceptable to JH PCBA, because good shipping weight every year, so we get relative good shipping price and support from them.

china
DHL
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esm
fedex
honggong post air mail
TNT
ups

Production Process 21: After-Sales Service

JH PCBA provide 6X24h prompt and professional PCB&PCBA service for you, any problem please feel free to contact our team, we will try to feedback you asap in 24h.

By email: sales@jh-pcba.com, or by phone 0086-755-29922552, or

PCB Manufacturing Process

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