Stacked Semiconductor Die Measurement for Bond Line Thickness
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Solution Overview
Problem
Conventional methods for measuring die-to-die separation in stacked semiconductor devices are wasteful, costly, and often require destructive mechanical cross-sections or delayed electrical testing, which can lead to variations in solder joint thickness, warpage, and misalignment, affecting the quality of thermo-compression bonding operations.
Innovation Solution
Incorporating measurement features, such as fiducial markers, on the semiconductor dies that can be imaged to determine the separation and thickness of interconnects, allowing for non-destructive assessment of die-to-die separation and quality of bonding operations in real-time, using image capture devices and processing systems to analyze the distances between these features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional destructive mechanical cross-section methods are used to measure die-to-die separation, then measurement can be performed, but the semiconductor device is damaged and yield is reduced
Solution Approach 1:
The patent creates optical copies (images) of the semiconductor device using imaging systems that capture light reflected from or transmitted through the device. These optical copies allow measurement of die-to-die separation without physically contacting or damaging the device. The imaging system creates a visual representation that can be analyzed to determine bond line thickness and separation distances.
Solution Approach 2:
The patent replaces mechanical cross-sectioning methods with optical imaging methods. Instead of using mechanical tools to physically cut and examine the device, the invention uses light-based imaging systems to non-destructively measure the same features. This substitution eliminates mechanical damage while maintaining measurement capability.
2Measurement precision
If delayed electrical testing is used to assess bonding quality, then measurement can be performed, but manufacturing time is increased and productivity is reduced
Solution Approach 1:
The patent performs measurements immediately after the bonding operation while the device is still in the manufacturing process. By implementing imaging-based measurement right after bonding, the system provides real-time feedback without requiring delayed electrical testing. This preliminary action allows for immediate quality assessment and potential process adjustments.
Solution Approach 2:
The patent introduces an intermediary imaging system that bridges the bonding process and quality assessment. Instead of directly performing electrical testing which requires complete device assembly and takes time, the imaging system provides an intermediate non-destructive measurement method that can be performed earlier in the process flow, accelerating the overall manufacturing cycle.
3Ease of manufacture
If variations in heat and force during bonding operations are not controlled, then bonding process is simpler, but solder joint thickness varies and interconnect quality deteriorates
Solution Approach 1:
The patent implements a feedback system where imaging measurements of bond line thickness are taken after bonding operations. These measurements provide information about the actual bonding results, which can be fed back to adjust bonding parameters for subsequent devices. This feedback loop maintains manufacturing precision while allowing for process optimization.
Solution Approach 2:
The patent uses imaging measurements to detect variations in bond line thickness caused by parameter variations during bonding. By monitoring these parameters (heat, force, time) and their effects on the final bond quality, the system can adjust parameters to maintain consistent solder joint thickness while preserving the relative simplicity of the 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
This approach enables accurate, non-destructive measurement of die-to-die separation and bonding quality immediately after the thermo-compression bonding operation, increasing yield and reducing manufacturing costs by avoiding physical damage and delayed electrical testing, while ensuring consistent and high-quality interconnects.
Implementation Method 1
receive an image of the semiconductor device
Data Source
AI summary
Semiconductor devices having measurement features and associated systems and methods are disclosed herein. In one embodiment, a semiconductor device includes a plurality of stacked semiconductor dies each having measurement features formed along an outer periphery of a surface thereof. One or more image capture devices can image the semiconductor device and a controller can detect the measurement features in imaging data received from the image capture devices. The controller can further determine the distance between two or more of the measurement features to estimate a bond line thickness between semiconductor dies in the stack.