Wet Etching Silicon Micropatterns Using HF-Resistant Composite Masks
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Solution Overview
Problem
Conventional semiconductor manufacturing processes face limitations in forming silicon or silicon compound micropatterns with high aspect ratios due to pattern collapse and warping during dry etching, and the cost and efficiency issues associated with increasing photoresist and organic carbon film thicknesses.
Innovation Solution
A novel wet etching method involving the selective application of a hydrofluoric-acid-resistant material to an organic carbon film layer, followed by wet etching with a hydrofluoric acid solution, to form a silicon or silicon compound micropattern, enhancing corrosion resistance and preventing pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of photoresist and organic carbon film is increased to form deeper silicon patterns, then the pattern depth is improved, but the pattern collapses and warps during dry etching
Solution Approach 1:
The patent changes the etching method from dry etching to wet etching using hydrofluoric acid solution, which allows for etching deeper silicon patterns without causing pattern collapse or warping. The wet etching process provides better pattern stability while achieving the required depth, resolving the contradiction between pattern depth and stability.
Solution Approach 2:
The patent uses a composite structure consisting of an organic carbon film layer combined with a hydrofluoric-acid-resistant inorganic film layer (such as SiON). This composite mask structure provides both the necessary etching depth capability and pattern stability during the wet etching process, preventing collapse and warping while enabling deep pattern formation.
2Length of stationary object
If the thickness of organic carbon film layer is increased to achieve greater etching depth, then the pattern depth is improved, but the deposition time and cost increase
Solution Approach 1:
The patent employs a composite mask structure where a relatively thin organic carbon film layer is combined with a hydrofluoric-acid-resistant inorganic film layer. This composite approach achieves the required etching depth without needing to excessively increase the thickness of the organic carbon film alone, thereby reducing deposition time and cost while still enabling deep silicon pattern etching.
Solution Approach 2:
The patent changes from dry etching to wet etching using hydrofluoric acid, which has superior etching speed and depth capability for silicon. This parameter change allows achieving greater pattern depth without proportionally increasing the mask layer thickness, thus reducing deposition time and manufacturing cost.
3Speed
If conventional dry etching is used to form deep silicon patterns, then the etching speed is sufficient, but the pattern warps and breaks during the process
Solution Approach 1:
The patent changes the etching method from dry etching to wet etching using hydrofluoric acid solution. This parameter change maintains sufficient etching speed for deep silicon patterns while dramatically improving pattern stability, preventing warping and breaking that occur during dry etching of deep patterns.
Solution Approach 2:
The patent uses a composite mask structure of organic carbon film and hydrofluoric-acid-resistant inorganic film that provides robust support during wet etching. This composite structure enables the formation of deep silicon patterns with high stability, preventing the warping and breaking issues encountered with conventional dry etching while maintaining efficient etching speed.
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 allows for the formation of silicon or silicon compound patterns with high aspect ratios without warping, while being more economical and stable than traditional dry etching processes, with optimal results achieved within a specific thickness range of the hydrofluoric-acid-resistant material.
Implementation Method 1
wet etching the resultant organic carbon film layer using an aqueous solution containing hydrofluoric acid
Implementation Method 2
coating an organic carbon film layer with a hydrofluoric-acid-resistant material so that the hydrofluoric-acid-resistant material is selectively attached to the organic carbon film layer
Data Source
AI summary
A process of realizing a silicon micropattern having a large aspect ratio in a semiconductor-manufacturing process, and a novel wet etching method that includes treating an organic carbon film layer so that a hydrofluoric-acid-resistant material is selectively attached to the organic carbon film layer and then wet etching the same using an aqueous solution containing hydrofluoric acid, thus forming a pattern, are proposed. In the method of forming the pattern by wet etching, etching is performed so that an active region having a depth of several μm in an object to be etched is not damaged when a pattern having a small CD is formed, thereby exhibiting an effect of providing a method of forming a micropattern.