Overview
IEC 62047-8:2011 is an international standard published by the International Electrotechnical Commission (IEC) focusing on the measurement of tensile properties of thin films used in semiconductor and micro-electromechanical systems (MEMS) devices. This standard specifies the strip bending test method, which offers a high level of accuracy and repeatability, while reducing alignment and handling efforts compared to traditional tensile testing methods.
The method detailed in IEC 62047-8:2011 applies to thin film test pieces with thicknesses ranging from 50 nm to several micrometers and requiring an aspect ratio (length-to-thickness) greater than 300. The strip bending approach utilizes a hanging strip-also referred to as a bridge-between two fixed supports, commonly found in MEMS or micro-machine fabrication. This design facilitates easier fabrication and scalability for quality control purposes.
Key Topics
Strip Bending Test Method
- Uses a hanging strip specimen fixed at both ends.
- Measures tensile properties through bending-induced deflection.
- Suitable for very thin films where conventional tensile tests are challenging.
- Allows simple automation and high throughput testing.
Test Apparatus Requirements
- Actuator: Linear actuators such as piezoelectric or servo motors with a displacement resolution finer than 1/1000 of the maximum test deflection.
- Load Tip: Wedge-shaped indenter tip, made from hard materials like diamond or sapphire, designed for line contact with the film. The tip radius must be larger or equal to the film thickness and smaller than L/50 (L = specimen length).
- Alignment Mechanism: Ensures load tip and test piece are aligned within 1 degree of angular deviation to avoid measurement errors.
- Sensors: High-resolution force and displacement sensors (resolution better than 1/1000 of max force and deflection), using capacitive, LVDT, or optical principles.
- Environmental Control: Testing under stable temperature and humidity conditions to minimize thermal drift during measurement.
Test Piece Design
- Manufactured using MEMS fabrication processes identical to those for actual device production.
- Thickness between 50 nm and several microns.
- Aspect ratio longer than 300 (length to thickness).
- The strip shape is optimized for ease of fabrication relative to standard tensile test specimens.
Test Procedure and Analysis
- Measures vertical deflection and calculates tensile properties based on bending stress.
- Easily automated for consistent results.
- Data analysis includes compensation for test apparatus effects and misalignment influences.
- Detailed guidelines provided for data reporting and evaluation of results.
Applications
IEC 62047-8:2011 is primarily applied in the semiconductor industry and MEMS fabrication for quality control and material property characterization purposes. Specific applications include:
- Thin Film Characterization: Measuring the mechanical tensile properties of thin films used in micro-electronic and MEMS devices.
- MEMS Production Quality Control: Monitoring mechanical integrity of thin films during or after fabrication, enabling high throughput testing for mass-produced micro-machines.
- Research and Development: Assisting in the development of new thin film materials and microfabrication processes by providing reliable tensile property data.
- Device Reliability Testing: Validating thin film performance in microsystems where mechanical stress can affect device operation.
Due to its ability to test extremely thin films with minimal handling and high precision, this standard supports advancing microfabrication technologies and ensuring the reliability of next-generation semiconductor and MEMS products.
Related Standards
- IEC 62047 Series: Covers a broader spectrum of standards related to semiconductor devices and micro-electromechanical systems.
- ISO/IEC Directives, Part 2: Guides standard preparation, important in conjunction with IEC 62047-8 for adherence to international norms.
- Other mechanical testing standards for thin films and MEMS devices, which complement IEC 62047-8 by covering alternative methods like nanoindentation or microtensile tests.
Keywords: IEC 62047-8, strip bending test, tensile property measurement, thin films, semiconductor devices, MEMS, micro-electromechanical devices, quality control, test apparatus, microfabrication, tensile testing, high accuracy measurement, thin film mechanical properties, alignment mechanism, force and displacement sensors.
Open preview (PDF)Semiconductor devices - Micro-electromechanical devices - Part 8: Strip bending test method for tensile property measurement of thin films
