Like any other printed circuit board, rigid PCBs are manufactured by following a particular procedure. Here, we will discuss each step in the entire manufacturing process.
- Material Preparation: The process begins with the bare production boards. These are cleaned using chemicals, before they are sent for the application of photo resist film. Generally an automated conveyor line is used to transport multiple pieces. The intention of this is to ensure that the boards do not get damaged in any way. It is also performed to ensure a fast manufacturing process.
- Exposure of Circuit Pattern: Once the panels have undergone the application of the photo resist, the board is then laid with the various circuit artwork patterns. This process is performed by exposing the board to UV light, to help transfer the circuit images onto the production panels. This process can be performed to single or both sides of the board.
- Etching: With the circuit pattern having been transferred onto the board, the next step is etching. This is where circuit patterns are chemically etched onto the board. This process is performed by specialized handling equipment and automated chemical etching machines.
- Drilling: Once the circuit pattern has been etched onto the board, the next step is to drill the holes for the circuit patterns. It is important that the drilled holes are of a particular size, adhering to exact specifications. Generally, PCB manufacturers utilize two types of equipment to perform this process. Specialized drilling machines with several drill mechanisms can be used to create holes in multiple boards. They also utilize laser drills to get clean, precise holes in a very short period of time.
- Copper Plating: With the drilling complete, the board can now undergo the copper plating process. This is where additional copper is applied onto the circuit board to create layer-to-layer interconnections. For this purpose, manufacturers utilize automated copper plating systems. They apply the copper onto the plated through holes.
- Coverlay Application: For protection and performance purposes, the PCB is covered with a coverlay laminate. Polyimide coverlays are one of the popular options for rigid PCBs. This process comprises aligning and tacking the laminates into place. This process can be performed by hand, or with automated machines.
- Coverlay Lamination: With the coverlay aligned and tacked, it now needs to be laminated to the board. The boards are placed in specialized lamination machines. These machines apply a combination of vacuum, heat, and pressure. This ensures that the laminated is properly stuck to the board.
- Stiffener Application: This is an optional step performed by PCB manufacturers. However, most designs do use this component. Stiffeners are supportive components that are used to prevent the lamination to prevent it from moving, or becoming loose. Generally, stiffeners are applied prior to the coverlay lamination process. They are adhered to the board using heat, vacuum, or pressure.
- Mounting: Once all the components and lamination has been completed, the PCB needs to be assembled. Generally, Plated Through Hole (PTH) mounting technology is used for rigid PCBs. In this process, the leads of the components are passed through the drilled holes. The leads are then soldered to pads on the opposite side of the circuit board.
- Testing: For a PCB to be considered fit for an application, it has to meet the requirements of the following testing procedures – electrical, AOI, and functional. Electrical testing involves using flying probe test machines to ensure that all the electrical connections such as shorts, opens, and capacitance, of the PCB are working properly. Automated Optical Inspection (AOI) involves using an optical imaging system to check the PCB for faults, and soldering and assembly defects. Functional testing is the final step. The functional test machine verify that the PCB’s hardware is free of any defects.
These are the basic steps used in the production of a rigid PCBs. These PCBs can be constructed with single, double, and multiple layers. For a PCB to meet all requirements of the application, it is important to provide detailed information about the application to the PCB manufacturer. This will allow him to design the PCB according to your needs.
| PCB Manufacturing Capabilities |
| Specifications |
Standard Technology |
Advanced Technology |
| Number of Layers |
1- 12 |
14 – 40 |
| Board Material |
FR4
FR406
IS410
Kapton
Shin-Etsu – Epoxy
Adhesive System
Rogers – Epoxy
Adhesive System
Dupont FR – FR Acrylic
Adhesive System
Dupont LF -LF Acrylic
Adhesive System
Adhesiveless Base Materials |
Aluminum Core
Arlon
CEM
Copper Core
FR408
Getek
Nelco 4000
Rogers 3000
Rogers 4000
Rogers 5000
Taconic TLY
Polyimid
|
| Minimum Board Thickness |
2 layer – 0.010″
4 layer – 0.020″
6 layer – 0.020″
8 layer – 0.062″
10 layer – 0.062″
12 layer – 0.062″ |
2 layer – 0.005″
4 layer – 0.010″
6 layer – 0.031″
8 layer – 0.040″ |
| Maximum Board Thickness |
2 layer – 0.125″
3-12 layer – 0.200″ |
0.250″ |
| Maximum Board Size |
16″ x 22″
12″ x 21″
22″ x 28″ |
10″ x 16″
16″ x 22″
12″ x 21″
22″ x 28″ |
| Copper Thickness |
0.5 oz -3 oz |
4oz – 6 oz |
| Hole Aspect Ratio |
7: 1 |
15:01 |
| Minimum Hole Size |
0.008″ |
0.006″ |
| Minimum Trace/Space |
0.006″/0.006″ |
0.003″/0.003″ |
| Minimum |
0.010″ |
0.003″ |
| Drill-to-Copper |
|
|
| Minimum Pitch |
1 mm |
0.3 mm |
| Final Finish |
HASL (Solder)
Lead Free Solder
Copper
Gold
Gold Fingers
White Tin
OSP |
HASL
Gold (ENIG/Hard/Soft)
Selective Gold
Immersion Silver
OSP
White Tin |
| Solder Mask |
LPI:
Green
Black
Red
Blue
Yellow
White
Clear |
LPI:
Green
Black
Red
Blue
Yellow
White
Clear
Mix-and-match
Wet Mask
Dry Film |
| Coverlay |
FR Coverlay
LF Coverlay
Shin-Etsu
Flexible Soldermask |
|
| Silk Screen |
White
Black
Yellow |
White
Black
Yellow
Green
Red
Blue |
| PCB Fabrication |
Scoring
Route & Retain |
Jump Scoring
Route & Retain
Milling |
| Additional Features |
Plated Slots
Non-plated Slots
Controlled Dielectric
Covered Vias
Counter Sinks
Counter Bores
Dual Access Flex
Suspended Leads |
Plated Edges
Plated Milling
Plated Counter Bores & Counter Sinks
Edge Castellation
Controlled Impedance
Silver Filled Vias
Non-Conductive Filled Vias |
| Quality Standards |
IPC 6012 Class 2
Electrical Testing
100% Netlist Testing
TDR Testing |
Milspec 31032
Milspec 55110
Milspec 50884
IPC 6012 Class 3
100% Netlist Testing
TDR Testing |
| Special Technology |
|
Blind & Buried Vias
Laser Drilled Vias
Mechanically Drilled Micro Vias
Metal Core Boards
Burn-in Boards
Rigid-Flex Boards
Flex Boards
Micro Circuits |
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