[vol.11] April 2021


Solder Bump Inspection

1.Solder Bump Inspection
Solder bump is a conductive bump that connects a chip or die to a PCB or substrate. If a solder bump is defective, this can produce a defect in the product due to the inability for the bump to electrically connect between chip and substrate. A reliable 3D AOI inspection system is needed in production to detect the many types of solder bump defects prior to the soldering/assembly process to ensure the quality and reliability of the end product.


2. Inspection Equipment – Xceed MICRO
PARMI’s Xceed MICRO, ultraprecision 3D AOI for Semi-conductor packaging, inspects solder bumps’
1) area 2) height 3) volume 4) offset 5) bridge and 6) coplanarity in a single scan. Xceed MICRO even renders precise 3D images of micro solder bumps, which are about 50 µm in size. With its exceptionally fast speed on scanning speed and real-time inspection data processing, Xceed MICRO is capable of maintaining short cycle times irrespective of the number of bumps or pads on the substrate that require inspection.


3. Inspection Items– Height Coplanarity
The most significant inspection data for electrical connections between a chip and the PCB are the height and coplanarity of the solder bumps. Xceed MICRO’s S/W for height inspection sets a datum point to each solder bump’s surroundings and computes every single bump’s height data in the ROI (Region of Interest), so it guarantees a high reliability.

Bump coplanarity is an inspection attribute that identifies a defect if it exceeds the upper or lower spec limits based on the LMS (Least Mean Square) of the entire bump. With these algorithms, and PARMI’s exclusive warpage compensation technology, Xceed MICRO is able to accurately inspect for bump coplanarity even on a warped PCB.