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Table 1 shows the test conditions. The test confirmed
the fluctuation (degradation) of insulation resistance
due to different surface treatments of the PCB.
Tests were prepared using the following 3 types of
surface treatments for specimens.
➀ Clean only
➁ Coating with non-cleaning flux after cleaning
➂ Solder treatment after cleaning and coating with noncleaning
flux
Temperature
and humidity
+60°C
90%RH
500 hours
Applied
voltage
25 V DC
2-2 Evaluation system and Measurement
Conditions
2-2-1 Evaluation system
Fig.2 shows an external view of the IM evaluation
system equipment, a system block diagram, and gives
specifications.
External view
Table 1 Test conditions
Details of surface treatments
· Clean: The substrate surface was washed with alcohol
(IPA) using ultrasonic cleaning, then dried.
· Coating with non-cleaning flux: Resin type noncleaning
flux was coated evenly on the surface, then
dried for 30 minutes at +100°C.
· Solder treatment: Solder dip was done for 5 seconds
at +260°C in a solder bath.
Substrate surface treatment
➀ Clean-only
➁ Coating with non-cleaning flux after cleaning
➂ Solder treatment after cleaning and coating with non-cleaning flux
System block diagram
System controller section
Uninterruptible
power supply
System
Controller
Printer
GP-IB
Specifications
Leak current detection:
to detect sudden changes in leak current due to IM progressing and contacting
counter electrode. (From leak current detection to electric field
stress OFF, response time: msec/point)
Leak current detection range: 1 - 100mA (1mA step)
Stress applied current: 3 - 100V DC (1V step)
DC current measurement range: 3 pA - 100mA
Resistance measurement range: 10 6 W - 3 ´ 10 13 W (when 100 V applied)
Continuous testing time: Max. 9,999 hours
Measurement interval: Variable (Min. 6 min.)
Measurement time: 80 sec./25 points + charging time
(user specified)
Measurement applied voltage: 3 - 100 V DC (1 V step, stress applied
voltage and individual settings possible)
Number of measurement points: 25 points (Max. 300 points)
System rack
GP-IB
Measurement
controller
GP-IB
Intrumentation section
E-BUS
GP-IB adapter (PMS-CG)
System control, temperature and humidity
monitor, alarm control
Parallel I/O
Ultra high resistance
measuring device
6 13
(10 to 10 )
Power unit for
stress application
(3 V to 100 V, DC)
(Stress OFF setting possible)
Leak current
detection
Scanner for
micro current
Fig.2 IM evaluation system (Model: AMI-025-P, made by Tabai Espec)
10 12
10 11
10 10
10 9
10 8
10 7
10 6
10 5
Triaxial cable
Environmental test
chamber options
Temperature and
humidity chamber,
or
Highly accelerated
temperature and
humidity stress
test chamber,
and others
Specimen
· Example of how leak current detection works
: Cyclical measurement
: Leak current detection
Leak currnt
detection level
setting
10 20 30 40 50 60 70 80 Hours (h)
14 ESPEC TECHNOLOGY REPORT No.2