BGA IC Soldering Technology

Overview of X-ray inspection system

Applications of X-Ray Inspection Technology

Hidden Solder Joint (ex BGA)
Dense solder joints (ex BGA) difficult to install test probes
Areas that are difficult to photograph with general cameras due to the presence of a mirror surface (ex, solder joint monitoring equipment after reflow process)
Pros : Quick inspection (vs destructive inspection)

Purpose of Use

Detection of the Defects

Main Inspection Items :
bridging, open, insufficient, excess,
missing balls, misregistration,
package "popcorning",

Processing Failure Analysis

Trend Analysis :
solder volume, solder joint shape

Quality Analysis

For Efficient Detection

X-ray image acquisition technique
Understanding the Analysis Technology of X-ray Image

X-ray image acquisition technology (Solder Joint inspection field)

Ffilm based X-ray Inspection
The process is complicated, requires expertise, is slow, and has a high shooting cost, while precise images can be obtained.
Filming video Principle of Filming
Real time X-ray system
The Overcome of the Weakness of Film Based TechnologyHaving some problems of Voltage Blooming, Pincushion Distortion
→ Overcome with Flat Detector Technology (however, Flat Detectors are expensive)
Various Sizes
desk top ~ 10 M x 10 M
The Various Voltage Ranges: the Several kV ~ the Hundreds of kV
Suitable Voltage for BGA inspection
Structure of Copper Thermal Radiator - Higher Voltage Required
High Sensitivity Camera - Lower Voltage Required
SAM(scanning Acoustic Microscopy)
Ultrasonic, Inspection by immersion in medium (water, alcohol), 230 MHz → 25 μGap
A-SAM - Point ㅣ B-SAM - Line ㅣ C-SAM - Surface
Effective for the Voids Inspection within Under Fill
Feeler Gage
New Gauge
Square Corner
Stand-off Measurement
low cost
BGA Stand-off measurement
laser, Contact Sensor
reflow - uniformity, 0.75mm ball
0.60mm → 0.45 mm , after reflow
Destructive analysis methods
In terms of problem solving, sample destruction
Molding with Resin → Location Estimation
Open, Crack accidentally occur
during the inspection process
Dye Penetrant
Inspection by penetration of dyes,
fluorescent substances (UV Light)