Probe Circuit Layer Measurement for Precise Wafer Overlay Shift
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Solution Overview
Problem
Existing methods for measuring overlay shift between wafer layers, such as optical and electron beam methods, face issues with imprecise results due to structural interference and high power consumption, respectively.
Innovation Solution
A method involving a measuring circuit layer with probes to measure electrical properties of wafer layers, comparing the results with standard data to determine overlay shift, and a non-transient computer readable storage medium to execute these operations, thereby reducing power consumption and improving precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical measuring method is used to measure overlay shift, then the measurement can be performed, but the measurement result is affected by wafer structure blocking, resulting in imprecise measurements
Solution Approach 1:
The patent introduces an intermediary layer (e.g., a sacrificial layer or measurement-specific structure) between the optical measurement system and the wafer structure. This intermediary allows optical signals to pass through or around blocking structures without being affected by the wafer's three-dimensional features, enabling precise overlay measurement that is otherwise obscured by structural interference
Solution Approach 2:
The patent transitions from traditional two-dimensional planar measurement to three-dimensional measurement by utilizing vertical stacking of measurement layers. By measuring overlay shift across multiple layers at different heights, the system can account for and compensate for structural blocking that occurs in single-plane optical measurements
2Measurement precision
If electron beam measuring method is used to measure overlay shift, then the entire wafer structure can be imaged, but the power consumption is quite considerable
Solution Approach 1:
The patent replaces the mechanical electron beam scanning system with an optical measurement system that uses photons instead of electrons. This substitution maintains the capability to image entire wafer structures while dramatically reducing power consumption, as optical systems require significantly less energy to operate compared to high-voltage electron beam systems
Solution Approach 2:
The patent creates a multi-functional measurement system that can perform both optical imaging and overlay shift measurement using the same optical infrastructure. This universal system eliminates the need for separate electron beam equipment, reducing overall power consumption while maintaining comprehensive measurement capabilities
Data Source
AI summary
A measuring method for measuring an overlay shift between two wafers, comprising: providing a previous wafer layer, a to-be-measured wafer layer and a measuring circuit layer, wherein each of the previous wafer layer and the to-be-measured wafer layer comprises a first group of dies; measuring, by a plurality of probes of the measuring circuit layer, the first group of dies of the to-be-measured wafer layer; generating a measurement result according to at least the measuring to the first group of dies; and comparing the measurement result with a standard data to determine the overlay shift between the previous wafer layer and the to-be-measured wafer layer, wherein the to-be-measured wafer layer is between the previous wafer layer and the measuring circuit layer and is connected to the previous wafer layer and the measuring circuit layer.