Semiconductor Patterning with Heat-Treated Recess Masks
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Solution Overview
Problem
In semiconductor device manufacturing, the non-uniform height of the object layer's upper surface can lead to defocusing phenomena during the photoresist process, resulting in undesired shapes and layouts of the photoresist pattern, which affects the formation of accurate masks and patterns.
Innovation Solution
A method involving the formation of a first recess in a substrate, a heat-treated spin-on-hardmask (SOH) mask, and a subsequent etching process using a third mask layer with higher etching tolerance, ensuring uniform height and thickness of mask layers to prevent defocusing and achieve desired pattern shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photoresist process is performed on a photoresist layer formed on an object layer with non-uniform height, then the photoresist pattern cannot be formed with desired shape, but increasing the thickness of the photoresist layer to cover the height variation would increase the complexity of the manufacturing process and require additional planarization steps
Solution Approach 1:
The patent applies preliminary action by forming a first mask layer and performing a heat treatment process before the photoresist process. The heat treatment process pre-modifies the mask layer to ensure uniform etching characteristics, eliminating the need for additional planarization steps and maintaining process simplicity while achieving desired pattern accuracy
Solution Approach 2:
The patent changes the physical-chemical parameters of the mask layer through heat treatment, transforming it into a form that provides uniform etching rate and tolerance. This parameter change enables the mask layer to compensate for underlying height variations without requiring photoresist layer thickness increase or additional process steps
2Manufacturing precision
If a mask layer is formed to compensate for height variation, then etching uniformity improves, but the etching process becomes more difficult to control due to varying material properties
Solution Approach 1:
The heat treatment process fundamentally changes the material parameters of the mask layer, creating a uniform physical-chemical state that is highly tolerant to etching. This parameter transformation makes the etching process easier to control by providing consistent etching rates and characteristics across the entire substrate area
Solution Approach 2:
The patent creates a composite structure where the heat-treated mask layer combines the benefits of uniform coverage and enhanced etching tolerance. The treated mask layer acts as a composite material that integrates both the protective function and the etching control function, simplifying the overall etching process
3Manufacturing precision
If multiple mask layers are formed to achieve uniform height, then the number of process steps increases, but removing excess mask material requires additional etching steps
Solution Approach 1:
The heat treatment process is performed as a preliminary action that prepares the mask layer for subsequent etching. This single preparatory step enables the mask layer to maintain uniform thickness without requiring multiple deposition steps, and facilitates easy removal of excess material through the enhanced etching tolerance property
Solution Approach 2:
By changing the physical-chemical parameters of the mask layer through heat treatment, the patent enables the mask material to be more easily removed via etching. This parameter change reduces the energy and steps required for mask removal, improving overall pattern formation efficiency
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 prevents defocusing issues and allows for the precise formation of active patterns and structures in semiconductor devices, ensuring accurate layouts and improved manufacturing efficiency.
Implementation Method 1
performing a heat treatment process on the first mask layer
Data Source
AI summary
A method of forming a pattern is provided. The method includes: forming a first recess in a substrate; forming a first mask layer on the substrate that extends into the first recess; performing a heat treatment process on the first mask layer; removing an upper portion of the first mask layer to form a first mask in the first recess, the first mask comprising a lower portion of the first mask layer; forming a second mask on the substrate and the first mask, the second mask comprising a material having a tolerance with respect to an etching process that is greater than that of the first mask; and performing an etching process on the substrate using the second mask as an etching mask to form the pattern on the substrate.