Photomask Phase Shift Hard Mask Split Pattern Manufacturing
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Solution Overview
Problem
Current photolithography techniques face challenges in achieving precise pattern transfer onto semiconductor wafers, particularly in fin-type field effect transistors (FinFETs), due to the need for high resolution and precise spacing between features, which existing resolution enhancement techniques like OPC, OAI, DDL, and PSM do not adequately address.
Innovation Solution
The method involves forming a photomask with a phase shift layer and a hard mask layer on a light transmitting substrate, using a split mask pattern processed through multiple exposure and etching steps with different machines to achieve precise pattern transfer, allowing for improved depth of focus and precision in feature formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single machine is used for pattern transfer, then manufacturing simplicity is maintained, but manufacturing precision and depth of focus are insufficient for high-density IC patterns
Solution Approach 1:
The patent divides the photomask pattern into multiple separate patterns (first pattern and second pattern) that are transferred by different machines. This segmentation allows each machine to optimize for its specific pattern requirements, with the first machine handling patterns requiring higher precision and the second machine handling patterns with different precision requirements, thereby resolving the contradiction between manufacturing precision and device complexity.
2Manufacturing precision
If multiple exposure processes are used to improve pattern precision, then manufacturing precision improves, but manufacturing time increases
Solution Approach 1:
The manufacturing process is segmented into multiple exposure processes, where different machines perform different exposure tasks simultaneously or in optimized sequences. The first exposure process transfers the first pattern with high precision requirements, while the second exposure process transfers the second pattern. This segmentation enables parallel processing and optimization of each exposure step, improving overall manufacturing precision while managing manufacturing time through efficient process orchestration.
3Measurement precision
If resolution enhancement techniques like OPC and PSM are applied, then pattern resolution improves, but device complexity and process difficulty increase
Solution Approach 1:
The patent applies resolution enhancement techniques by segmenting the pattern transfer into multiple specialized exposure processes. Instead of using complex OPC or PSM techniques on a single machine, the pattern is divided into multiple simpler patterns that can be transferred by different machines using more straightforward exposure methods, thereby achieving high resolution while reducing overall process complexity.
Solution Approach 2:
The patent moves the complexity from the optical processing dimension to the process organization dimension. Rather than making single-machine optical systems more complex through OPC/PSM, the solution introduces a temporal and organizational dimension by using multiple machines and multiple exposure processes, achieving high resolution through process architecture rather than optical 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
This approach enhances the precision and throughput of photomask manufacturing by allowing different machines to handle patterns with varying precision requirements, reducing manufacturing time by 8%-20% and improving the alignment and resolution of features on the wafer.
Implementation Method 1
a phase shift layer and a hard mask layer are formed on a light transmitting substrate
Data Source
AI summary
A method of manufacturing a photomask includes at least the following steps. First, a phase shift layer and a hard mask layer are formed on a light transmitting substrate. A predetermined mask pattern is split into a first pattern and a second pattern. A series of processes is performed so that the hard mask layer and the phase shift layer have the first pattern and the second pattern. The series of processes includes at least the following steps. First, a first exposure process for transferring the first pattern is performed. Thereafter, a second exposure process for transferring the second pattern is performed. The first exposure process and the second exposure process are executed by different machines.