Overlay Shift Measurement Using Replicated Reference Patterns
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor module production, accurately detecting overlay shifts between successive planes is crucial for maintaining pattern quality and connection integrity, but existing methods lack simplicity and reliability in defect detection and tolerance range adherence.
Innovation Solution
A method involving image acquisition of reference and measurement elements, comparison for shift value determination, and output generation if the shift exceeds a predefined tolerance, utilizing a microscope with a camera for sub-pixel accuracy pattern matching and user interface-driven selection of reference elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex measurement methods are used to ensure accurate overlay shift detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses reference elements that are copied or replicated across the substrate, with each reference element containing identical first and second pattern elements. By comparing the positions of these replicated patterns, the system achieves accurate overlay measurement without requiring complex measurement algorithms or equipment
Solution Approach 2:
The patent transforms the overlay measurement problem into a pattern position comparison problem by changing the measurement parameter from direct shift detection to relative pattern positioning. This allows using standard imaging equipment with image processing to achieve precise measurements
2Productivity
If multiple process steps and layers are applied to increase integration density, then productivity is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent incorporates reference elements with first and second pattern elements into the substrate during the manufacturing process itself, before final inspection. This preliminary integration of measurement features allows for in-process overlay verification, enabling timely detection and correction of alignment issues without requiring additional post-processing steps
Solution Approach 2:
The patent implements a feedback mechanism where overlay measurements are taken during production, and results are used to adjust subsequent processing steps. The system compares measured overlay shifts against tolerance values and provides feedback for real-time process correction, maintaining precision despite multiple processing steps
3Reliability
If stringent quality requirements are imposed to maintain pattern quality, then reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The patent makes the substrate self-measuring by integrating reference elements directly into its structure. The first and second pattern elements on the substrate serve as built-in measurement targets, eliminating the need for external measurement equipment or complex setup procedures. The substrate essentially measures itself through its own embedded reference features
Solution Approach 2:
The patent simplifies the inspection process by transforming complex overlay analysis into straightforward pattern position comparison. By changing the measurement approach to focus on relative positions of predefined patterns rather than analyzing entire complex circuits, the system maintains stringent quality control while significantly easing operational complexity
Data Source
AI summary
A method for measuring overlay shift is disclosed. An image is acquired of at least one reference element that comprises at least one first pattern element in a first plane and at least one second pattern element in a second plane. An image of a measurement element is likewise acquired. The shift value between the reference element and measurement element is ascertained by comparing the image of the reference element with the image of the measurement element. An output on a user interface indicates whether a predefined tolerance value is being exceeded.