Snake-Pattern Fin Cutting to Prevent Exposure-Induced Fin Damage
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Solution Overview
Problem
Existing fin cutting methods using photomasks with island or pot patterns often result in fin damage due to exposure failures or over-exposure, which is not effectively addressed in the miniaturization of semiconductor devices.
Innovation Solution
A method employing a photomask with a snake-shape pattern is used to form a photoresist layer over fins, allowing for precise cutting by transferring and etching the pattern, thereby avoiding damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If photomasks with island or pot patterns are used for fin cutting, then the cutting process can be performed, but fin damage occurs due to exposure failures or over-exposure
Solution Approach 1:
The photomask pattern is divided into multiple snake-shaped segments that sequentially define the cut regions. Each snake-shape pattern consists of multiple connected cut regions that are exposed in a specific sequence, allowing precise control over the etching process and preventing over-exposure damage to fins.
Solution Approach 2:
The photomask is designed with pre-defined snake-shape patterns that anticipate the exact regions requiring cutting. The exposure process follows the predetermined snake-shape path, ensuring that only the intended fin regions are exposed and etched, while adjacent fins remain protected from damage.
2Device complexity
If traditional photomask patterns are used, then the cutting process is simple, but exposure precision is insufficient leading to fin damage
Solution Approach 1:
The photomask employs snake-shape curved patterns instead of traditional straight or simple geometric shapes. The curved snake-shape path allows the exposure beam to smoothly transition between cut regions, improving exposure precision and enabling accurate definition of complex fin cutting patterns without damaging adjacent structures.
3Adaptability or versatility
If photomask with island patterns is used, then the process is conventional, but over-exposure occurs causing fin damage
Solution Approach 1:
The snake-shape pattern design converts the potential harm of over-exposure into a benefit by using the continuous curved path to naturally limit exposure duration in each region. The snake-shape geometry ensures that the exposure beam passes through each cut region for a controlled time, preventing over-exposure while maintaining the ability to handle various fin cutting configurations.
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 effectively minimizes fin damage by providing a more accurate and controlled cutting process, ensuring the integrity of the fin structures during the cutting process in semiconductor device manufacturing.
Implementation Method 1
A photoresist pattern is formed in the photoresist layer corresponding to the snake-shape pattern by exposing and developing
Implementation Method 2
The fins are cut by transferring the photoresist pattern and etching cut parts of the fins
Data Source
AI summary
A method of cutting fins includes the following steps. A photomask including a snake-shape pattern is provided. A photoresist layer is formed over fins on a substrate. A photoresist pattern in the photoresist layer corresponding to the snake-shape pattern is formed by exposing and developing. The fins are cut by transferring the photoresist pattern and etching cut parts of the fins.