Stackup Overview

Stackup is the soul of Multi-layer PCB.it refers to the arrangement of copper layers and insulating layers that make up a PCB prior to board layout design.Stackup information includes the layers order,which is layer 2,,which is layer 3.Many customers sent us gerber file without stackup or layer order information. That means we can not proceed the PCB. If you do not have customs stackup ,you also need to provide  layers information to PCB manufacturers.
​Here is an example. TOP/inner 1/Plane1/Bottom,or CMP/LY2/L15/Bottom.  So we can know inner 1 or LY2 is layer 2. The core material and Prepreg is flexible for us to meet the final thickness.
Another important information is one core for 4 Layer PCB,2 cores for 6 layers PCB and 3 cores for 8 layers PCB.The dielectrical (Prepreg)thickness should not be more than 0.3mm, otherwise, we have to use more than two Prepreg material with higher cost.
The above information is very helpful for any PCB factories,it helps us to understand the layers order and the stackup.​We prefer you to specify  the PCB layers order and stackup information in the gerber too.

Standard PCB stackup

Standard ​PCB stackup is for the normal PCBs without impedance or high-speed requirements,it is not critical but to meet the final thickness.Below is an example for standard FR4 PCB ,4 layer with 1.6mm thickness.
Standard 4 Layer PCB with one core
Layer Type Thickness
Layer 1 Copper 0.035mm 1OZ
Pre-preg 2116*1 0.1mm
Laye 2 Copper 0.035mm 1OZ
Core FR4 1.2mm
Layer 3 Copper 0.035mm 1OZ
Pre-preg 2116*1 0.1mm
Layer 4 Copper 0.035mm 1OZ
4 Layer PCB with one core to stackup is standard stackup.
Layer 2 and Layer 3 is in the same core.
4 Layer PCB with two cores customs stackup
Layer Type Thickness
Layer 1 Copper 0.035mm 1OZ
Pre-preg 2116*1 0.1mm
Laye 2 Copper 0.035mm 1OZ
Core FR4 1.2mm
Layer 3 Copper 0.035mm 1OZ
Pre-preg 2116*1 0.1mm
Layer 4 Copper 0.035mm 1OZ
4 Layer PCB with two cores is customs stackup.Layer 1 and Layer 2 is in the first core ,Layer 3 and Layer 4 is in the second core. The PCB is made like a 6 layer.
The left is our standard 12 layer PCB stackup with high TG material.
Prepreg regularly used
PP type Thickness Resin DK
2116 0.12 55% 4.5
7630 0.2 50% 4.7
7628 0.17 43% 4.7
1080 0.075 65% 4.2

Impedance PCB stackup

Impedance PCB usually have customs stackup,it specifies the trace width,space in gerber. Then,the most important is the stackup ,it may change the final result.Usually, there are two impedance  types in PCB manufacturers.One is Singled-ended ,another is Differential impedance.However,there are many models for PCB factories to test the impedance. The impedance trace is in inner layer or out layer,solder mask or not, ​Coplanar or not. see our impedance PCB to get more information about impedance.Below are some models .
​Outer layer—Single-ened type
Application：Outer layer over solder mask
​H1: Dielectric thickness 
Er1:Material DK
W1:Trace Width(bottom)
W2:Trace Width(top)
D1:Space from trace to ground
T1:Copper thickness
C1:soldermask thickness over raw material
C2:solder mask thickness over copper
CEr:Solder mask Dk
​Outer layer--Differential ​ Type
Application：Outer layer over solder mask
​H1: Dielectric thickness 
Er1:Material DK
W1:Trace Width(bottom)
W2:Trace Width(top)
S1:Trace space
T1:Copper thickness
C1:soldermask thickness over raw material
C2:solder mask thickness over copper
C3:soldermask thickness over raw material
CEr:Solder mask Dk
How to design a 4 layer impedance PCB with 0.8mm thickness？With more than 10 years experience, 50ohm and 100 or 90 ohm impedance PCB should be like this.Below is just an example,you can use different cores and PP to get different trace width.
Please contact us to get the impedance stackup table.