Reticle Pattern Orthogonalization for Lithography Accuracy
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Solution Overview
Problem
As semiconductor design progresses to increasingly smaller line widths, interference such as diffraction effects cause deviations in the geometry created in the photoresist from the intended pattern on the reticle, leading to inaccuracies in photolithography processes.
Innovation Solution
The implementation of a method for semiconductor device pattern generation that includes generating a reticle pattern through inverse transformation, orthogonalization, and optical proximity correction (OPC) to compensate for lithography process imperfections, ensuring accurate reproduction of critical geometric features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If radiation patterning is used to create patterns on semiconductor wafers, then the intended geometry can be transferred to photoresist, but diffraction effects cause the created geometry to deviate from the intended pattern
Solution Approach 1:
The patent applies optical proximity correction (OPC) techniques to pre-distort the reticle pattern before fabrication, compensating for anticipated diffraction effects. The system calculates correction patterns and modifies the reticle design in advance so that after lithography, the final pattern matches the intended geometry despite diffraction during exposure
Solution Approach 2:
The patent converts the harmful diffraction effects into a beneficial correction process by using the known diffraction behavior to calculate and apply compensatory patterns. The system uses diffraction models to predict deviations and creates opposite corrections in the reticle, turning the predictable harmful effect into a controllable parameter
2Productivity
If smaller line widths are used in semiconductor design, then device density increases, but diffraction effects become increasingly problematic causing greater geometry deviations
Solution Approach 1:
The patent changes the parameter of line width in the reticle design by applying OPC modifications. The system calculates corrected line widths and patterns that account for diffraction effects, which become more significant at smaller dimensions. The correction parameters are adjusted based on the specific line width being fabricated
3Ease of manufacture
If traditional photomask or reticle patterns are used without correction, then the manufacturing process is simple, but the geometry created in photoresist deviates from the intended pattern
Solution Approach 1:
The patent introduces an intermediary computational step between design and fabrication. The OPC system acts as a mediator that translates the intended pattern into a corrected reticle pattern, accounting for process variations and diffraction effects. This intermediary processing layer maintains ease of manufacture while improving pattern fidelity
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
This approach enhances the accuracy and reliability of semiconductor device pattern generation by correcting for lithography-induced deviations, improving process yield and design rule compliance.
Implementation Method 1
A form of radiant energy such as, for example, ultraviolet light may be passed through a radiation patterning tool and onto a radiation-sensitive material (such as, for example, photoresist) associated with a semiconductor wafer
Implementation Method 2
Various forms of interference such as, e.g., diffraction effects, can cause the geometry created in the photoresist to deviate from the geometry the reticle was intended create on the photoresist
Data Source
AI summary
In one embodiment, a computer system a processor and a memory module comprising logic instructions stored on a computer readable medium which. When executed, the logic instructions configure a processor to create a reticle pattern for use in a lithography process, apply an orthogonalization process to the reticle pattern to create an orthogonalized reticle pattern, and use the orthogonalized reticle pattern in an optical proximity correction process.