Highly Accelerated Stress Test – HAST

Highly Accelerated Stress Test – HAST Testing Services

A highly accelerated stress test (HAST) is an essential part of environmental testing that combines high temperature, high humidity, pressure, and time to test a component’s reliability under harsh environments. HAST is an efficient and faster alternative to traditional temperature-humidity testing for testing moisture penetration in semiconductors, thin-film resistors, solar panels, and pharmaceutical products to reveal corrosion failures due to packaging, materials, seals, and joints. A higher amount of stress and pressure better simulates the effects of humidity and temperature in the laboratory and helps predict component failures within days. HAST testing is also employed in transportation, packaging, and shelf-life studies of products. HAST tests under the same temperature, humidity, and pressure variables are performed in testing labs with voltage bias (BHAST) to accelerate moisture penetration and related induced failures within the device or product.

Empirically, the acceleration factor for high humidity is calculated as:

AF_H = e^const (RH_s^ղ-RH_o^ղ)

Where,

const – Value that normally ranges from 0.1 to 0.15

RH_s – Stressed humidity

RH_o – Operating environment humidity

ղ – Empirically derived constant (usually 1 < n < 5)

The acceleration factor for high temperatures is calculated as follows:

AF_T = e^{(E_a/k)(1/T_o-1/T_s)}

Where, 

E_a – Activation energy for the temperature induced failure

k – Boltzmann constant

T_o – Operating temperature in Kelvin

T_s – Stressed temperature

Consequently, the overall acceleration factor for the unbiased HAST testing is:

AF_HAST = AF_H * AF_T

In HAST, the samples are put inside a HAST board that are able to withstand severe test conditions. Owing to their capability to tolerate the harsh HAST conditions, the HAST boards are quite expensive. 

The HAST test, which is a faster version of the standard non-condensing THB (Temperature Humidity Bias) test, has the benefit of utilising greater temperatures (up to 149°C) and higher pressures to hasten temperature and moisture-induced failures in around one-tenth the time of THB. The standard parameters for HAST and BHAST testing are 130°C and 85% RH, but they can change as per each test requirement.

Our testing labs are well equipped to carry out Highly Accelerated Stress Test (HAST) and provide the best results to our clients based in the USA and other parts of the world. We at Infinita Lab perform not only routine tests, but also custom tests designed in our testing labs as per the client’s specific requirements.

Testing Parameters in Highly Accelerated Stress Test (HAST)

• (dry) High temperature 130C, RH 85%, pressure 33.3 psia
• (wet) High temperature 110C, RH 35%, pressure 17.7 psia

Highly Accelerated Stress Test (HAST) Common Uses

• Improve product reliability
• Improve corrosion resistance of products
• Predict heat and moisture induced failure modes

Industries using Highly Accelerated Stress Test (HAST)

• Electronics
• Semiconductors
• Solar Energy
• Pharmaceuticals
• Space Applications

Highly Accelerated Stress Test (HAST) Laboratories

• Oneida Research Services
• Element Material Technology
• Delserro Engineering Solutions
• Tektronix Inc

More Details

• Understanding Highly Accelerated Stress Test (HAST) in IC Qualification
• Characteristics of HAST test
• HAST testing chambers