[vol.5] August 2020

PCB Warpage Measurement

1. What is “PCB Warpage Measurement”?
PARMI provides a function to measure the warpage of PCB’s during the solder paste inspection (SPI) and automated optical inspection (AOI) processes. PCB warpage occurs in the process of fabricating PCB’s or in the SMT manufacturing process. It is important to detect PCB warpage in the early stages of the assembly process because PCB warpage can affect to the whole process of printing, mounting, and soldering. PARMI’s SigmaX (3D SPI) and Xceed (3D AOI) can inspect and record PCB warpage in parallel with the PCB inspection process with no impact on the inspection cycle time.

2. Basic Principal Of Warpage Measurement
The virtual plane (the horizontal plane, which is the benchmark of height when measuring warpage) can be computed by the ROI area of the PCB, and then the difference between the maximum height and the minimum height can be calculated.
Within the measurement area, measure the difference between the maximum height and the minimum height by comparing it with the maximum height allowance.
Height difference ≤ Maximum height allowance → „GOOD“
In these ways, it is possible to measure warpage although the PCB surface is tilted.

3. Measurement Type
1) The warpage measurement of the entire PCB area
: by using the height data of the entire PCB area

2) The warpage measurement of specific PCB area
: by setting up a specific area for measurement

3) The measurement of warpage of individual circuits on a panel
: by measuring the warpage above the maximum height
allowance in specific modules of the board

※ The measurement type has been written based on Xceed.

4. Case of Application
    : Solder Bump PCB Warpage Measurement by Xceed (3D AOI)

PARMI’s Xceed 3D AOI machine performs simple and accurate inspection of solder bump PCB, which has thin boards so that it is warped easily. At this time, it is possible to inspect without additional inspection time as well as regardless of the size of the PCB. One of the companies using solder bump PCB warpage measurement of PARMI is Company S, and it can also be applied to a wide range of industries using Solder bump PCB. Xceed provides accurate results for warpage measurement, and improvement of overall product quality.