Direct-Write Lithography Couponing Without Wafer Damage
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Solution Overview
Problem
Conventional couponing methods in semiconductor fabrication are destructive, generating particles and contamination, and limit inspection with sensitive metrology tools, making process optimization inefficient and costly.
Innovation Solution
A non-destructive couponing method using direct-write lithography to selectively pattern wafers, creating pseudo coupon regions without physical deformation, enabling efficient process optimization and inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional couponing methods are used to create test samples, then process optimization can be performed, but particles and contamination are generated and inspection with sensitive metrology tools is limited
Solution Approach 1:
The patent replaces the mechanical cutting system with a direct-write lithography system that uses actinic radiation to pattern the photoresist layer. This substitution eliminates mechanical contact and particle generation while achieving the same coupon isolation objective through photochemical processes.
Solution Approach 2:
The patent changes the physical state and properties of materials through controlled parameter changes. The photoresist layer transitions from unexposed to exposed state through controlled radiation exposure, and then from exposed to developed state through chemical development, enabling non-destructive coupon creation without mechanical forces.
2Quantity of substance
If conventional couponing methods are used, then test samples can be generated, but the wafer is physically deformed and destroyed
Solution Approach 1:
The patent replaces mechanical cutting and physical separation methods with direct-write lithography and selective removal processes. This substitution allows multiple coupon regions to be defined on the same wafer without physical deformation, maintaining wafer integrity while generating multiple test samples.
Solution Approach 2:
The patent creates multiple coupon regions by digitally defining their locations and dimensions in a data structure, then reproducing these patterns across the wafer using direct-write lithography. This copying approach allows identical or varied coupon geometries to be created without physical contact or wafer destruction.
3Object-affected harmful factors
If direct-write lithography is used to create coupon regions, then non-destructive patterning is achieved, but multiple process steps are required
Solution Approach 1:
The patent merges multiple process steps into an integrated workflow: the photoresist layer is deposited once, then multiple coupon regions are defined through sequential or parallel direct-write exposure operations, followed by a single development step. This merging reduces overall process complexity compared to creating each coupon separately.
Solution Approach 2:
The patent performs preliminary actions by depositing the photoresist layer and defining all coupon region patterns before any fabrication processes are executed. This preliminary patterning allows multiple different fabrication processes to be tested on different coupon regions without repeating the patterning step, reducing overall process complexity.
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 efficient, non-destructive process optimization with reduced contamination and improved compatibility with sensitive metrology tools, allowing for better statistical analysis and recipe generation.
Implementation Method 1
exposing the photoresist layer to a patterned actinic radiation without using a photomask
Implementation Method 2
exposing the photoresist layer to a patterned actinic radiation creating a latent pattern
Data Source
AI summary
A method of processing a substrate that includes: depositing a photoresist layer over the substrate; performing a cyclic direct-write lithographic process using a direct-write lithography tool, the cyclic direct-write lithographic process including a plurality of cycles, each of the plurality of cycles including: exposing the photoresist layer to a patterned actinic radiation without using a photomask, defining one of a plurality of coupon regions, where the plurality of coupon regions are configured to generate a plurality of test samples on the substrate for evaluating process conditions of a fabrication process; exposing the one of the plurality of coupon regions; and performing the fabrication process on the one of the plurality of coupon regions.