IEC 62047-37-2020 Semiconductor devices – Micro-electromechanical devices – Part 37: Environmental test methods of MEMS piezoelectric thin films for sensor application.
This part of IEC 62047 specifies test methods for evaluating the durability of MEMS piezoelectric thin film materials under the environmental stress of temperature and humidity and under mechanical stress and strain, and test conditions for appropriate quality assessment. Specifically, this document specifies test methods and test conditions for measuring the durability of a DUT under temperature and humidity conditions and applied voltages. It further applies to evaluations of direct piezoelectric properties in piezoelectric thin films formed primarily on silicon substrates, i.e. piezoelectric thin films used as acoustic sensors, or as cantilever-type sensors. This document does not cover reliability assessments, such as methods of predicting the lifetime of a piezoelectric thin film based on a Weibull distribution.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 62047-30, Semiconductor devices – Micro-electromechanical devices – Part 30: Measurement methods of electro-mechanical conversion characteristics of MEMS piezoelectric thin film
3 Terms and definitions No terms and definitions are listed in this document.
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• IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp
4 Testing procedure
4.1 General The degree of degradation in a device under test (DUT) is evaluated by measuring the piezoelectric properties of the DUT before and after applying the environmental stress of temperature and humidity. Figure 1 shows the general flow of the testing procedure.
4.2 Initial measurements The methods of measurement used in the environmental tests shall conform to the methods described in IEC 62047-30. The ambient conditions for measurements shall include an ambient temperature of 25 °C ± 3 °C, a relative humidity of 45 % to 75 %, and an atmospheric pressure of 86 kPa to 1 06 kPa.
4.3.1 DUT setup and environmental conditions For tests requiring continuous operation of the DUT, the DUT is placed in a test bed that can be adjusted to the prescribed temperature and humidity to conditions. The test conditions are monitored to verify that no abnormalities occur when the chamber environment reaches the prescribed conditions. For tests that do not require continuous operations of the DUT, the DUT may be placed in the test bed and the test bed may be deposited in the chamber, but the test bed need not be put in the chamber. When depositing and removing the DUT and test bed for either test, the operator shall ensure that:
• water does not drip onto the DUT;
• the DUT is not directly immersed in water.
4.3.2 Test duration
Test duration is described in 5.1 .1 to 5.1 .7.IEC 62047-37 pdf download.