Semiconductor Lithography Shot Overlap Correction
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Solution Overview
Problem
In semiconductor device manufacturing, the overlap of electron beams during optical lithography leads to errors in pattern accuracy due to surplus electrons at edges, causing critical dimension errors and degrading the final pattern's precision.
Innovation Solution
A method is developed to correct overlapping shots by calculating a radiation-influenced pattern based on area differences and surplus electrons, adjusting beam dosage and critical dimensions, and applying proximity effect correction to enhance pattern accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If overlapping shots are used to reduce the number of shots required, then productivity is improved, but manufacturing precision deteriorates due to surplus electrons causing critical dimension errors
Solution Approach 1:
The patent changes the beam dosage parameter for overlapping shots by calculating a correction value based on the overlap area. The system determines the area where shots overlap, calculates the number of surplus electrons in that region, and adjusts the beam dosage accordingly to compensate for the electron accumulation effect, thereby maintaining pattern accuracy while using overlapping shots for improved productivity
Solution Approach 2:
The patent implements a feedback mechanism where the actual overlap area and surplus electron count are calculated based on the shot pattern, and this information is fed back to adjust the beam dosage. The system continuously monitors the overlap conditions and modifies the exposure parameters to compensate for the radiation influence, ensuring that the final pattern matches the intended design despite using overlapping shots
2Manufacturing precision
If beam dosage is increased to compensate for electron diffusion, then manufacturing precision is improved, but use of energy increases
Solution Approach 1:
The patent applies local quality by differentiating the beam dosage adjustment based on the specific location and extent of shot overlap. Instead of uniformly increasing beam dosage across the entire pattern, the system calculates the overlap area for each shot pair and applies dosage correction only to the overlapping regions. This localized approach compensates for electron diffusion effects precisely where needed while avoiding unnecessary energy consumption in non-overlapping areas
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 method reduces errors in the final pattern by correcting beam dosage and critical dimensions of overlapping shots, improving pattern accuracy and reducing the number of shots required, thus enhancing semiconductor device manufacturing efficiency.
Implementation Method 1
radiating a variable shaped beam (VSB) to a surface on which the final pattern is to be formed based on the corrected overlapping shots
Implementation Method 2
the overlap of electron beams during optical lithography leads to errors in pattern accuracy due to surplus electrons at edges
Data Source
AI summary
A method of manufacturing semiconductor devices is disclosed. The method includes determining fractured shots that do not overlap each other based on a final pattern; determining overlapping shots that are shots that overlap each other based on the final pattern; generating area difference data by comparing the areas of the overlapping shots and the fractured shots with each other; calculating a radiation influenced pattern based on the area difference data; and correcting the overlapping shots based on the radiation influenced pattern.