IEC 62047-17-2015 pdf download.Semiconductor devices – Micro-electromechanical devices – Part 17: Bulge test method for measuring mechanical properties of thin films.
Pressuring device should be equipped to apply a specified continuous pressure with a controlled rate or a certain level of pressure to the membrane window to be bulged. Pressure media can be oil, gas and distilled water. In general, the device can be composed of a pressure sensor and pressure controller. The controller should be with accuracy of 1 % in full test scale.
NOTE At the pressures encountered in the tests, gas is over a million times more compressible than typical liquids such as oil and distilled water.
5.2.2 Bulge (pressure) chamber The pressure chamber should be as compact as possible, to reduce the compliance of the test system. The volume, which has to be pressurized and which potentially contributes to the compliance, would be minimized. In the case liquid is used to pressurize the test system, the system contains as little air as possible because even a small air bubble trapped inside the test system can dominate the system’s compliance. It is recommended that the system including the chamber be designed so that there are no places where air bubbles can hide and that the liquid can be refilled easily. Special care shall be taken not to introduce air bubbles when samples is mounted and removed.
The material of the chamber should be chosen considering the pressure media for the test and testing pressure range. In the case liquid is used to pressurize the test system, it is recommended that the testing apparatus be made out of transparent acrylic sheet in order to see air bubbles and then to minimize them trapped within the chamber. The bulge chamber is connected to the pressurizing device and thus allows a specimen to be deformed with fine control. The specimen is mounted on the bulge chamber by mechanical clamping or epoxy gluing method, etc.
NOTE In the case of capacitance measurement type, the bulge chamber has an electrode and a mechanical spacer.
The electrode, which measures height change of a bulge specimen due to the deformation, is made of copper-coated PCB. A mechanical spacer that is located between the specimen and the electrode controls a sensitivity of capacitance change by adjusting thickness of the spacer. The pressure inside the chamber shall be monitored and measured through suitable pressure sensor which can be installed directly to the chamber or connected though tube transporting the pressure without loss of the pressure to be measured. It is recommended that exposition of the area of the pressure sensor to the pressure media should be minimized and it has no indentation or internal cavities trapping air.
Nonlinearity and hysteresis of the pressure sensor is recommended to be less than 0,5 % and be calibrated according to the pressure standard established in each country as a National Standard.
5.2.3 Height measurement units The height measurement unit should be installed in a position suitable to measure the deformation of the membrane window and have a function of a continuous measurement which is needed in order to determine the maximum deformation of the membrane window bulged with applying pressure. The maximum deformation of the membrane window can be determined from the measurement in full-field or top of the bulged area using the laser interferometric system or capacitance type measurement system, which is described in detail in Annex B.IEC 62047-17 pdf download.