Semiconductor Bond Void Detection Using SWIR Interference Thermography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for void detection in direct bonding of semiconductor devices, such as scanning acoustic microscopy and active thermography, suffer from limitations including low throughput, need for immersion, and limited resolution, especially in detecting subsurface voids with dimensions smaller than the depth of the defect.
Innovation Solution
An active thermographic system utilizing infrared radiation and ultrasonic acoustic waves, combined with short-wave infrared interference, to enhance detection resolution and fidelity of subsurface voids in semiconductor direct-bonded interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanning acoustic microscopy is used for void detection, then detection capability is provided, but throughput is low and immersion is required
Solution Approach 1:
The patent replaces the mechanical acoustic wave-based scanning acoustic microscopy system with an optical/thermal system using infrared radiation and thermography. This substitution eliminates the need for mechanical scanning and immersion fluids, enabling non-contact, high-speed void detection through thermal wave propagation and infrared imaging, thereby dramatically increasing throughput while maintaining detection capability.
2Productivity
If active thermography is used for void detection, then throughput is improved, but resolution is limited to subsurface voids with lateral dimension comparable or larger than the depth of the defect
Solution Approach 1:
The patent applies ultrasonic vibration to the semiconductor device, which generates thermal waves through acoustic heating. The ultrasonic frequency mechanical vibration creates thermal energy that propagates through the material, allowing detection of small subsurface voids through their thermal response. This approach overcomes the resolution limitation of conventional active thermography by using high-frequency acoustic heating that can resolve features smaller than the thermal diffusion length.
Solution Approach 2:
The patent changes the physical parameters of the inspection method by using ultrasonic frequency mechanical vibration combined with thermal wave propagation. This parameter change enables the system to achieve both high throughput and high resolution for small subsurface voids, as the ultrasonic heating creates thermal contrasts that can be detected with infrared imaging, overcoming the traditional trade-off between speed and resolution.
3Ease of manufacture
If direct bonding is used to adjoin semiconductor devices, then bonding without intermediate materials is achieved, but void formation at the bond interface occurs
Solution Approach 1:
The patent uses the semiconductor device itself as the medium for ultrasonic vibration transmission. The device's own mechanical properties and thermal characteristics are exploited to generate and detect thermal waves, eliminating the need for external coupling media or complex vibration transmission systems. This self-service approach enables effective void detection while maintaining the simplicity of the direct bonding process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system improves the speed and fidelity of defect detection by accurately identifying small subsurface voids through dynamic temperature changes and interference patterns, overcoming limitations of existing methods.
Implementation Method 1
As the applied source propagates through the material, the applied source interacts with internal defects
Implementation Method 2
an infrared camera captures the surface temperature changes over time
Implementation Method 3
ultra-sonic pulses are directed at the subsurface voids, reflected by the subsurface voids, and detected by an ultra-sonic transducer upon reflection
Implementation Method 4
a detector, wherein the collected-infrared light is directed to the detector along a collection pathway
Data Source
AI summary
Infrared radiation, and specifically short-wave infrared radiation, may be used as a heat source for an active thermography process in the context semiconductor inspection. Ultrasonic acoustic waves may also be used as a heat source for an active thermography process in the context of semiconductor inspection. Short-wave infrared interference may be used to detect dynamic temperature changes at internal surfaces of a semiconductor, and specifically near a semiconductor direct-bond interface. Either of the short-wave infrared radiation as the heat source or the ultrasonic acoustic waves as the heat source may be combined with the use of short-wave infrared interference to detect dynamic temperature changes, which allows for improved detection resolution. Short-wave infrared interference may also be used to directly detect subsurface voids at the semiconductor direct-bond interface. The short-wave infrared interference may or may not require thermal perturbation.