Fine Pattern Cutting with a Sacrificial Layer Etch Mask
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for cutting fine patterns in semiconductor manufacturing face challenges such as decreased process margin due to the removal of photoresist patterns during etching, leading to enlarged openings and reduced precision.
Innovation Solution
A method involving the formation of a line structure on a substrate with a sacrificial layer, where a first mask and photoresist pattern are etched to create openings, allowing for the selective removal of the pattern into multiple pieces without etching byproducts, thus maintaining precision and process margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photoresist pattern is used as etching mask, then fine pattern can be formed, but photoresist pattern is removed during etching process causing slope of sidewall to be lowered and width of opening to be enlarged
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary material between the photoresist pattern and the underlying structure. This sacrificial layer serves as a stable etching mask that does not get removed during the etching process, unlike the photoresist pattern. The photoresist pattern is formed first, then the sacrificial layer is deposited over it, allowing the photoresist to define the pattern while the sacrificial layer provides the stable masking function during etching, thus resolving the contradiction between pattern formation precision and process margin reliability
Solution Approach 2:
The patent segments the masking function into two separate components: the photoresist pattern that defines the fine pattern geometry and the sacrificial layer that provides stable etching mask functionality. This segmentation allows each component to perform its specific function optimally - the photoresist for precise pattern definition and the sacrificial layer for maintaining process margin during etching, thereby resolving the technical contradiction
2Ease of manufacture
If photoresist pattern is easily removed during etching, then etching process is simpler, but sidewall slope is lowered and opening width is enlarged
Solution Approach 1:
The sacrificial layer acts as an intermediary that absorbs the etching process complexity. Instead of requiring the photoresist pattern to remain intact during etching (which would complicate the process), the sacrificial layer is designed to be the etching mask that gets selectively removed. This intermediary approach simplifies the etching process while maintaining precise dimensional control of the opening through the sacrificial layer's stable masking properties
Solution Approach 2:
The sacrificial layer creates a copy or replica of the photoresist pattern structure that serves as the actual etching mask. This copied structure maintains the precise pattern geometry while providing the necessary stability during etching, allowing the photoresist pattern itself to be removed more easily without affecting the dimensional control of the final opening
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 effectively divides the pattern into multiple pieces with improved precision and process margin, reducing the risk of etching byproducts and maintaining the integrity of the fine pattern cutting process.
Implementation Method 1
At least one of a portion of the first mask, an upper portion of the pattern, and a portion of the sacrificial layer that are under the first opening may be partially etched using a first etching gas
Data Source
AI summary
In a method of cutting a fine pattern, a line structure is formed on a substrate. The line structure extends in a first direction, and includes a pattern and a first mask. The pattern and the first mask include different materials. A sacrificial layer is formed on the substrate to cover the line structure. The sacrificial layer is partially etched to form a first opening partially overlapping the line structure in a vertical direction. A portion of the first mask, an upper portion of the pattern and/or a portion of the sacrificial layer under the first opening are partially etched using an etching gas having no etching selectivity among the pattern, the first mask and the sacrificial layer. A lower portion of the pattern under the upper portion thereof is removed to divide the pattern into a plurality of pieces spaced apart from each other in the first direction.