Thermodynamic Micro-Strain Relaxation in Die Attach Adhesives during Thermal Soak
Thermal soak accelerates die attach viscoelastic micro-strain relaxation, reducing shear stress while driving physical aging, interface delamination, and Rth growth.
X-Ray Diffraction Strain Tracking
Structural Monitoring
Evaluation of the distortion in a crystal lattice by observing the shift in Bragg peaks provides a non-destructive analysis of stress. This technique is the basis of x-ray diffraction strain tracking, which calculates the spacing between atomic planes to determine the internal stress state of a material with high precision. It provides a direct link between the physical lattice constant and the mechanical strain present in the thin film.
Scientists use this method to monitor the structural health of microelectronic components during the manufacturing process. The ability to resolve small changes in the lattice spacing makes it a superior tool for quality control.
Analytical Principle
Diffraction occurs when the wavelength of the incident x-rays is comparable to interatomic distances. The peaks shift accordingly.
Instrumentation Setup
High-resolution diffractometers equipped with monochromatic sources and precise goniometers ensure the accuracy of the peak detection. The sensitivity of the system allows for the measurement of strains as small as one part in ten thousand. Regular calibration with a standard silicon powder sample verifies the angular accuracy of the detector.
Process Integration
Feedback from the x-ray diffraction strain tracking allows for the adjustment of deposition parameters to hit target stress levels. If the measured strain exceeds the design limit, the process flow is altered to prevent film peeling. Structural monitoring is necessary for the development of strained-silicon technologies that enhance carrier mobility.