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Multilayer PCB Fabrication

Multilayer PCB Fabrication

The layer count of PCB (Printed Circuit Board) determines its manufacturing technology difficulty and PCB manufacturing cost. PCB boards can be briefly classified into two categories: single-layer (single-sided) PCB and double-layer (double-sided) PCB. When it comes to high-end electronic products, a couple of signal layers can be added to the inside of PCB apart from surface routing due to some limitations in terms of board real estate and board design. During the manufacturing procedure, after routing for each layer has been finished with positioning and lamination completed, multiple layers of signals will be pressed into a single board that is called multilayer PCB. Therefore, a multilayer PCB refers to any piece of circuit board containing more than two layers of signals. Multilayer PCBs can be multilayer rigid PCB, multilayer flex PCB and flex-rigid multilayer PCB.Multilayer PCB Fabrication.

Necessity of Multilayer PCB

Due to the increasing use of IC (Integrated Circuit) package, interconnection lines become so dense that multi-substrate boards become necessary. In addition, some design problems, like noise, stray capacitance, crosstalk etc., are so protruding that should be solved through multilayer resolution. As a result, PCB design has to make sure that signal lines should be minimized and parallel circuits should be avoided, which is apparently difficult to be obtained in either single-sided or double-sided design. Therefore, multilayer PCBs come into being for the acquisition of perfect performance of circuits.

The original aim of multilayer PCB is to provide more freedom in terms of routing for circuits that are complex and/or sensitive to noise. There are at least three layers in a multilayer PCB and two layers are external with the left layer(s) synthesized inside insulating plate. The electrical connection in a multilayer PCB derives from plated through hole on the cross section of circuit board.

Advantages of Multilayer PCB

Smaller size
• Lower weight
Higher speed of signal transmission
• Constantly low impedance
• Better shielding effect
• Higher assembly density

Standard FeaturesStandardAdvanced
Maximum Layer Count46L100L
Maximum Panel Size 21×24″24×42″
Outer Layer Trace/Spacing50µm/50µm40µm/40µm
(1/3oz starting foil + platig)[0.0035″/0.0035″][0.0025″/0.003″]
Inner Layer Trace/Spacing45µm/45µm35µm/35µm
 (Hoz inner layer cu)   [0.003″/0.003″][0.002″/0.002″]
Maximum PCB Thickness3.2mm6.5mm 
Minimum PCB Thickness0.20mm (8mil)0.10mm (4mil)
Minimum Mechancial Drill Size0.20mm (8mil)0.10mm (4mil)
Minimum Laser Drill Size0.10mm (4mil)0.08mm (3mil)
Maximum PCB Aspect Ratio10:0125:01:00
Maximum Copper Weight5 oz [178µm]30 oz [1050µm]
Minimum Copper Weight1/3 oz [12µm]1/4 oz [9µm]
Minimum Core Thickness40µm 16µm 
Minimum Dielectric Thickness30µm 12µm 
Minimum Pad Size Over Drill 0.46mm 0.4mm 
Solder Mask Registration± 50µm± 25µm 
Minimum Solder Mask Dam76µm 64µm 
Copper Feature to Edge, V‐cut (30°)0.40mm 0.36mm 
Copper Feature to PCB Edge, Routed0.25mm 0.20mm
Tolerance on Overall ± 100µm ±50µm 
Rigid‐Flex & Flexible CircuitsYY
Buried and Blind ViasYY
Sequential LaminationYY
Impedance Control ± 10%± 5%
Hybrids & Mixed Dielectrics YY
Aluminum PCB’s YY
Non‐Conductive Via Fill (VIP) YY
Conductive Via Fill YY
Cavity Boards YY
Controlled Depth Drill and RoutYY
Edge Plating YY
Buried CapacitanceYY
Etch BackYY
In‐board BevelingYY
2‐D Bar Code PrintingYY

Multilayer PCBs can be served in so many industries including consumer electronics, medical care, aerospace, telecommunications, military, automotive, wearables, IoT etc. based on its benefits. Alcanta PCB has been striving to provide high-quality multilayer PCBs for customers with full concerns in terms of design, cost and lead time. Contact us and follow rainbows with Alcanta PCB!