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Simulation and characterisation methods for assessment of the thermo-mechanical reliability of microelectronics and microsystems


Thermo-mechanical reliability is becoming an increasing challenge in electronics and microsystems due to ongoing miniaturisation, higher power densities and stricter demands due to operation in harsh environments. The common approach for assessing the reliability of new microelectronics and microsystems entails destructive and non-destructive testing of physical prototypes. If necessary, changes are made to the design and new tests are carried out on adjusted prototypes. This process is repeated until a design is obtained that meets the criteria, which is time consuming and expensive.


Within the mevipro project, numerical and experimental tools are being developed to shorten the time required to design a component or product. In particular, the following results are to be exploited by TNO:

- Numerical models for determining the critical thermo-mechanical loads on microelectronics and microsystems (failure criteria for bulk materials and interfaces).

- Numerical models for predicting thermo-mechanical stresses in polymers during and after cure (adhesives, moulding compounds, underfill encapsulants).

- A method for determining the fatigue behaviour of thin wires or strips (e.g. electrical leads of electronics components, wire-bonds).

- A method for investigating the thermo-mechanical fatigue behaviour of solder or adhesive joints (thermal lap shear test).


Simulation techniques (models for thermo-mechanical behaviour of polymers, failure criteria) have been developed and assessed.

Methods for assessment of the fatigue behaviour of thin wires and the fatigue behaviour of solders and adhesives have been developed and assessed.

The thermal lap shear test has been demonstrated for the investigation of solder materials.

In a recently started national project, the ideas behind the wire fatigue test and the thermal lap shear test are being developed for investigating the thermo-mechanical behaviour of electrically conductive adhesives.

The results that are sufficiently mature (numerical models and characterisation experiments, wire fatigue experiments) are included in the portfolio of services that TNO offers to its customers in the electronics and microsystems field for reliability and lifetime assessment. These results are expected to be applicable in other fields as well possibly after some modifications.

Expected benefit:

In 2004, the MES department of TNO Industrial Technology derived about 2.5 MEuro turnover in the field related to product design, reliability and lifetime assessment for microelectronics and microsystems. Numerical simulation in combination with characterisation capabilities is considered as an important instrument by which TNO can distinguish itself from its competitors. By strengthening this field by means of the project results, the department expects to increase this turnover by 5 - 10 % leading to an additional 125 - 250 kEuro income annually.

In addition to the expected benefit for TNO itself, there is the benefit for TNO's customers having access to the results via TNO's services. The results enable them to react more rapidly to market demands and to deliver more reliable products giving them the possibility to increase their market shares.

Informations connexes

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Research Organisation
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