RA, Reliability Analysis

Component Board Level Test

Based on definition in IPC/JEDEC-9703, component board level test is refered to a  test conducted on a simplified test board which contains only one type of component, although multiple samples of the same component may be present. This board need not be similar to the final system board. The reliability test items include:

Board Level Thermal Cycling Test

Evaluate the thermal fatigue life of solder joint materials of electronic products, components or circuit boards under the influence of thermal stress. The failure standard is defined according to IPC-9701: failure is defined as a maximum of 20% nominal resistance increase within a maximum of five consecutive reading scans. The failure mode can be analyzed by cross section observation or dye and pry test. 

Board Level Drop Test

Evaluate the mechanical shock life of electronic products under the influence drop acceleration. According to the JESD22-B111, the component will be fixed on the base of the testing machine, and then proceed according to the test conditions. Test conditions include: maximum impact acceleration, impact time and velocity change. According to the failure definition, the first indication of resistance value of 100 ohms or 20% increase in resistance from the initial resistance if initial resistance is greater than 85 ohms followed by 3 additional such indications within the 5 subsequent drops.

Environmental Stress Test

Due to the diversification of the application environment of electronic products, reliability assessment of electronic products under different environmental conditions is become important. Common influence factors include temperature, humidity, and external forces. The influence factors can be simulated by test equipment, and the evaluation time can be accelerated to confirm the performance of the product in extreme environments.

Cheetah Inspection Inc. could provide the following environmental stress test:

  • Thermal Storage Test
  • Temperature/humidity Storage Test
  • Thermal Cycling Test
  • Thermal Shock Test
  • Temperature/humidity Cycling Test
  • Highly Accelerated Stress Test, HAST
  • Mechanical Shock Test
  • Bending Test

SIR, Surface Insulation Resistance

Due to the reduction of circuit line spacing and the increase of soldering density, the influence of flux residue on the circuit board become significant on the reliability of electronic products. Cheetah Inspection Inc. is able to evaluate the phenomenon under different line widths and line spacing. The test sample will be placed in an environment of temperature and humidity, and a certain voltage will be applied, and then the change of the insulation resistance between the lines will be observed.

Tin Whisker Test

Tin whisker is caused by the protruding growth of crystals due to the residual stress left by the tin plating layer in the electronic components, or the protruding of tin crystals caused by the solder material under long-term temperature stress. Generally, the formation rate of tin whisker is quite slow and the length is limited. However, under certain conditions (stress, temperature, etc.), tin whiskers have a higher growth rate. If the tin whiskers are grown too long, the risk of short circuits will increase.

Test items for tin whiskers:

Reliability Test (Temperature Cycle Test, Temperature/Humidity Storage Test)

JESD201 standard describes the environmental requirements for tin whiskers after tin and tin alloy surface treatment of various components, and defines the acceptable degree and grade of tin whiskers after different environmental stress tests such as temperature cycling, temperature and humidity storage.

Scanning Electron Microscope (SEM)

JESD22A121 standard defines the measurement method of tin whisker. Due to the small size of tin whiskers (μm level), it is necessary to photograph and measure with an electron microscope.