Imprint Apparatus Distortion Compensation via Variable Material Dispensing
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Solution Overview
Problem
Imprint systems face challenges in achieving accurate overlay due to distortions in substrates and templates caused by planarity deviations and image placement errors, leading to in-plane distortions that affect the precision of nanoscale pattern formation on semiconductor wafers.
Innovation Solution
An imprint apparatus with a processor that dispenses formable material based on distortions in the substrate and template, adjusting the areal density to compensate for planarity deviations and image placement errors, allowing for improved registration and alignment by creating a programmed deviation in the mold to match the substrate's distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the chuck is made as flat as possible through lapping and polishing, then the distortion of the wafer is reduced, but the manufacturing cost and complexity increase due to the limitations of lapping and polishing technology
Solution Approach 1:
The patent changes the parameter of chuck flatness from requiring extremely high physical flatness to accepting moderate flatness with programmable compensation. The system uses a map of height deviations and compensates through variable spacing elements that adjust the template-substrate distance dynamically across different regions, transforming a manufacturing precision problem into a controllable parameter adjustment problem.
Solution Approach 2:
The patent introduces an intermediary computational layer (processor and software) that mediates between the physical chuck imperfections and the final patterning accuracy. This intermediary processes height deviation maps and generates compensation patterns, acting as a bridge that eliminates the need for extremely precise mechanical manufacturing.
2Reliability
If the template conforms to a non-flat wafer, then contact is achieved across the surface, but in-plane distortions are introduced in the template affecting overlay accuracy
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and pre-compensating for the expected distortions. Before the actual imprinting process, the system creates a height deviation map and determines compensation patterns that will counteract the anticipated in-plane distortions, effectively neutralizing the harmful effect before it occurs.
Solution Approach 2:
The patent implements local quality by allowing different regions of the template-substrate interface to have different spacing characteristics. The variable spacing elements create locally optimized gaps that compensate for local height deviations, rather than applying a uniform spacing approach that would fail to address localized flatness issues.
3Ease of manufacture
If uniform areal density of formable material is dispensed, then the dispensing process is simple, but distortions in the substrate and template cause non-uniform pattern formation
Solution Approach 1:
The patent applies preliminary action by pre-calculating the non-uniform areal density distribution needed to compensate for known distortions. The processor uses the height deviation map to determine the optimal material distribution pattern before dispensing, so that the material is placed with the correct spatial variation to counteract the expected distortion effects during imprinting.
Data Source
AI summary
A method can include placing a substrate over a chucking region, wherein the substrate has a primary surface; quantifying a distortion in the substrate, the lithographic template, the imprint apparatus, or any combination thereof; and dispensing a formable material based at least in part on the distortion. The distortion can include a deviation in planarity, a magnification or orthogonality error or the like. In another aspect, an imprint apparatus can include a substrate holder including a chucking region; a template having an imprint surface that includes protrusions, wherein the protrusions define a primary surface; and a processor configured to determine an amount of a formable material to dispense in a particular area based at least in part on an distortion in the substrate, the lithographic template, the imprint apparatus, or any combination thereof.