A reliability test that repeatedly applies high and low temperatures to evaluate solder-joint fatigue and package cracking or delamination caused by differences in thermal expansion between materials.
Japanese name: 温度サイクル試験
Temperature cycling appears in 6 practice questions across 2 topics, including Reliability, Power semiconductors.
Field: Reliability
A semiconductor package is built from materials with different coefficients of thermal expansion: the silicon die, mold compound, lead frame or substrate, solder and the printed circuit board. Silicon's coefficient is small, about 3 ppm/K, while the board and solder expand several times more, so every temperature change turns the difference in expansion into strain on joints and interfaces. Each strain cycle is small, but repetition drives metal fatigue until cracks form. Temperature cycling concentrates this repetition into a short period and finds how many cycles it takes to cause failure.
Parts are cycled in an air chamber and held for a set time at each of the high and low temperatures. In JEDEC standards (the JESD22 series), temperature ranges such as −55 to 125 °C or −65 to 150 °C are typical conditions, with hundreds to thousands of cycles. The automotive AEC-Q100 uses conditions that depend on the temperature grade. Besides component-level tests, after which the package and internal bonds are examined, there are board-level tests that mount parts on a printed circuit board and count the cycles until the solder joints fail.
A typical failure is a fatigue crack in a solder joint; in a BGA, balls near the package corners tend to fail first. Inside the package, cracks at wire-bond joints or at the wire heel, delamination between mold compound and the die or lead frame, and cracks in the die or passivation film occur. Board-level tests detect breaks by monitoring the resistance of a daisy chain that connects many joints in series. Delamination is checked with scanning acoustic microscopy and internal cracks with cross-sections.
Thermal shock tests apply faster temperature changes than temperature cycling by quickly moving samples between hot and cold chambers or immersing them in liquids. Power cycling heats devices by passing current through them rather than heating them externally, repeating on-off cycles, and is important for evaluating power modules. To estimate field life from temperature-cycling results, the Coffin-Manson relation is used, in which cycles to failure are inversely proportional to a power of the temperature swing. For solder the exponent is said to be around 2, so halving the temperature swing increases cycle life about fourfold.
Answer: B. Cracks in solder joints and packages due to differences in materials' coefficients of thermal expansion
Temperature cycling repeatedly swings parts between hot and cold, for example −55 to 125 °C, for hundreds to thousands of cycles. Because die (about 3 ppm/K), substrate, mold compound and solder expand differently, each cycle induces strain, causing solder-joint fatigue, package cracks and delamination. The relationship between life and temperature swing is described by the Coffin–Manson law. Soft errors and refresh failures are evaluated by other tests.
Answer: A. The Coffin-Manson relationship
The Coffin–Manson law relates the magnitude of cyclic strain to the number of cycles to fatigue failure; for temperature cycling it is written N ∝ (ΔT)^(−m). For solder, m is around 2, so halving the temperature swing roughly quadruples cycle life. It is used to estimate life in milder field conditions from harsh temperature-cycling tests.
Both alternate between high and low temperatures, but thermal shock testing applies more abrupt changes, for example by moving samples between liquid baths. Temperature cycling changes temperature in air and holds each extreme for a set time, mainly evaluating joint fatigue from repetition.
For example, −55 to 125 °C or −65 to 150 °C are typical. The range and number of cycles depend on the applicable standard, the product's temperature grade and whether the test is done on components alone or on board-mounted parts.
The Coffin-Manson relation gives an acceleration factor from the ratio of test and field temperature swings. For solder the exponent is said to be around 2, and in practice models that also account for differences in mean temperature and cycles per day are used.
Temperature cycling repeatedly swings parts between hot and cold, for example −55 to 125 °C, for hundreds to thousands of cycles.
Which failures are mainly evaluated by temperature cycling …The Coffin–Manson law relates the magnitude of cyclic strain to the number of cycles to fatigue failure; for temperature cycling it is written N ∝ (ΔT)^(−m).
Which model expresses the fatigue life of solder joints und…AlN offers high thermal conductivity, while Si3N4 is mechanically strong and crack-resistant, favored in applications with severe temperature cycling such as EVs.
In high-power modules, what is the main purpose of the insu…Temperature cycling evaluates joint fatigue and drop testing evaluates shock resistance.
Which typical reliability test evaluates lifetime and failu…It specifies test items and conditions, such as high-temperature operating life, temperature cycling, humidity, ESD and latch-up, along with operating-temperature grades, and automotive semiconductors are generally qualified to it.
Which standard is widely used as the reliability qualificat…As an Amazon Associate I earn from qualifying purchases.
HTOL (high-temperature operating life test) AEC-Q100 Refresh ESD (electrostatic discharge) Latch-up BGA Underfill Arrhenius model Bathtub curve Electromigration