Highly Accelerated Life Test (HALT) and Highly Accelerated Stress Screening (HASS) are the test methods for improving the product reliability and are derived from the US military methods for design quality and manufacturing quality verification. They have now become the standard product verification methods in the US electronics industry. Those tests can shorten the time required to verify the reliability of a new product from 6 months or even a year to one week. The problems found from HALT/HASS test are almost the same as those found after the use of the product by the consumers. Therefore, HALT/HASS test method has been used as a necessary verification before the launch of a new product. Many international electronic product manufacturers outside the US also use the same or similar methods to improve product quality.

HALT is a test method for discovering the design shortcomings and potential weaknesses in the products by applying different stresses to the products. Those stresses include vibration, high and low temperature, temperature cycling, power switching cycle, voltage margin and frequency margin tests, etc. HALT is applied in the research and development stages of products for the purpose of discovering the weaknesses of product reliability as early as possible. It mainly includes the following:

a. Gradually apply stress until the product failures or malfunctions occur;

b. Take temporary measures to correct the failures or malfunctions of the products;

c. Continue gradually applying stress until the product failures or malfunctions occur again, and take corrective actions again;

d. Repeat the above steps of stress-failure-correction;

e. Identify the basic operational limits and basic destruction limits

HASS is mainly applied in the production stage to ensure that all improvements found in HALT are implemented. HASS includes the following:

a. Carry out the pre-screening and eliminate the hidden defects that may develop into obvious defects;

b. Perform the detection and screening to identify the obvious defects;

c. Failure analysis; improvement plan

● Chair of Climate Subcommittee of National Technical Committee on Environmental Standardization for Electrical and Electronic Products

● Machinery Industry Environmental Adaptability Testing Center

● CNAS proficiency testing provider (PTP) for low temperature test