Wafer Alignment Correction via Electrical Contact Resistance
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Solution Overview
Problem
The challenge in the semiconductor industry is accurately aligning wafers during processing stages due to smeared or blurred alignment marks, which hinders high precision alignment and miniaturization of IC devices, leading to lower yields and difficulties in detecting and measuring position accurately.
Innovation Solution
A system and method using electric contacts on a chuck and wafer, with arc-shaped contacts and a grounded plate, coupled with ammeters and a computing infrastructure to calculate displacement and centering alignment by measuring resistance differences, allowing precise angular alignment adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical alignment methods are used with alignment marks, then alignment can be performed, but the alignment precision deteriorates due to smeared or blurred alignment marks
Solution Approach 1:
The patent replaces the optical detection system with an electrical contact-based system. Instead of using optical methods to detect alignment marks on the wafer, the invention uses electrical contacts that make direct physical contact with the wafer surface. The alignment is determined by measuring electrical resistance or current through these contacts, which provides reliable detection independent of the optical quality or clarity of alignment marks.
Solution Approach 2:
The patent introduces electrical contacts as an intermediary between the wafer and the measurement system. These contacts serve as a mediator that translates the physical position and orientation of the wafer into measurable electrical signals (resistance or current), enabling accurate alignment detection without relying on the visual quality of alignment marks.
2Manufacturing precision
If higher alignment precision is required for miniaturization, then measurement accuracy must improve, but the difficulty of detecting and measuring alignment marks increases
Solution Approach 1:
The patent replaces the optical detection system with an electrical contact-based system. Instead of using optical methods to detect alignment marks on the wafer, the invention uses electrical contacts that make direct physical contact with the wafer surface. The alignment is determined by measuring electrical resistance or current through these contacts, which provides reliable detection independent of the optical quality or clarity of alignment marks.
Solution Approach 2:
The patent changes the measurement parameter from optical properties (reflectivity, absorption) to electrical properties (resistance, current). This parameter change enables high-precision alignment measurement because electrical measurements are not affected by the optical degradation of alignment marks that occurs during wafer processing.
3Adaptability or versatility
If photo-exposure masks are used for each processing step, then functional integration increases, but alignment difficulty increases due to accumulated errors
Solution Approach 1:
The patent implements a feedback mechanism where the electrical contacts continuously measure the actual position and orientation of the wafer at each processing step. This measurement feedback is used to detect and correct alignment errors, preventing their accumulation across multiple photo-exposure steps. The system can identify misalignment and adjust accordingly, maintaining high cumulative alignment accuracy even with multiple processing steps.
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
Enables accurate and precise alignment of wafers, improving yield and enabling further miniaturization of IC devices by providing a sensitive and reliable method for detecting and correcting alignment issues.
Implementation Method 1
The at least one contact is coupled to ammeters via low resistance connecting wires
Implementation Method 2
the at least one spring on an underside of the contact to provide an upward biasing force
Data Source
AI summary
A system and method is provided for correcting alignment of a product on a tool and, more particularly, to a system and method for correcting alignment of a wafer on a chuck of a tool. The system is a tool including at least one contact near a circumference of the tool and a grounded contact proximate to the at least one contact.