Wafer Overlay Shift Measurement Using Probe Circuit Layers
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Solution Overview
Problem
Existing methods for measuring overlay shift in 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, generating a measurement result, and comparing it with standard data to determine overlay shift, along with a non-transient computer readable storage medium to execute these operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical measuring is used to measure overlay shift, then the measurement can be performed, but the measurement result is affected by wafer structure and becomes imprecise
Solution Approach 1:
The patent introduces an intermediary layer (measuring circuit layer with probes) between the optical measuring system and the wafer structure. This intermediary layer transfers the measurement function from direct optical interaction with the wafer to electrical property measurement, eliminating the harmful effect of wafer structure on measurement precision
Solution Approach 2:
The patent replaces the optical measuring system with an electrical measurement system. Instead of using light to measure overlay shift directly on the wafer structure, the system uses probes to measure electrical properties (resistance, capacitance, etc.) of the wafer, substituting optical measurement with electrical measurement to avoid structural interference
2Measurement precision
If electron beam measuring is used to measure overlay shift, then the entire wafer structure can be shot with high voltage electron beam, but the power consumption is quite considerable
Solution Approach 1:
The patent replaces the high-power electron beam measuring system with a low-power electrical measurement system using probes. The measurement function is transferred from electron beam interaction to electrical property measurement, achieving the same measurement precision with significantly reduced power consumption
Solution Approach 2:
The patent changes the measurement parameter from optical/electromagnetic properties (requiring high energy) to electrical properties (requiring low energy). By measuring electrical characteristics such as resistance and capacitance instead of using high-voltage electron beams, the system achieves overlay shift measurement with minimal power consumption
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.