Etch Method Surface Modification for Semiconductor Selectivity
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Solution Overview
Problem
The semiconductor manufacturing process faces challenges in controlling the etch rate during wet etching operations due to insufficient selectivity between the sacrificial silicon nitride layer and underlying or nearby layers, leading to damage and uneven etch depths.
Innovation Solution
A surface modification treatment is applied to both the silicon nitride and silicon-containing layers using a silicon-containing compound and solvent, forming modified layers with different covalent bond strengths, allowing selective removal of the silicon nitride layer while protecting the silicon-containing layer during wet etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet etching is performed directly on the silicon nitride layer, then the etching process can proceed, but the selectivity between the silicon nitride layer and underlying/nearby layers is insufficient causing damage to other layers
Solution Approach 1:
The patent applies a surface modification treatment to the silicon-containing layers before the wet etching process. This preliminary action forms a modified layer with different etching characteristics that protects the silicon-containing layers during subsequent wet etching of the silicon nitride layer, thereby improving selectivity and preventing damage.
Solution Approach 2:
The surface modification treatment acts as an intermediary layer between the wet etchant and the silicon-containing layers. This modified layer has different covalent bond strengths that provide selective protection, allowing the etchant to remove the silicon nitride layer while sparing the underlying silicon-containing layers.
2Productivity
If wet etching is performed on the silicon nitride layer, then the sacrificial layer can be removed, but the etch rate is difficult to control due to loading effect and insufficient selectivity
Solution Approach 1:
The surface modification treatment is applied beforehand to create a protected state on the silicon-containing layers. This preliminary modification ensures that during the wet etching process, the etch rate is controlled and uniform across different areas, eliminating the loading effect problem and achieving precise etch depth control.
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
The method enhances selectivity and reduces damage to the silicon-containing layers, ensuring precise and uniform etch depths, thereby improving the manufacturing process for semiconductor structures.
Implementation Method 1
forming modified layers with different covalent bond strengths
Data Source
AI summary
An etching method with a surface modification treatment for forming a semiconductor structure is provided. The method includes providing a semiconductor substrate, forming a silicon nitride (SiN) layer on the semiconductor substrate, and forming a silicon-containing layer on the semiconductor substrate and beside the SiN layer. The silicon-containing layer includes a silicon dioxide layer, a n-type silicon-containing layer, a p-type silicon-containing layer or a combination thereof. The method further includes performing a surface modification treatment onto the SiN layer and the silicon-containing layer by using a surface modification solution, thereby forming a modified layer on the SiN layer and the silicon-containing layer. The method further includes removing a portion of the modified layer and its underlying SiN layer by a wet etching operation, while the other portion of the modified layer and its underlying silicon-containing layer remain, and removing the other portion of the modified layer.