Annealed Metal Oxide Etch Stop Layer for Semiconductor Devices
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Solution Overview
Problem
Conventional etch stop layers in semiconductor device manufacturing are prone to erosion during wet etching, leading to damage to underlying layers due to permeation of etchants between the etch stop layer and conductive layers, particularly in the fabrication of cylindrical memory cell capacitors.
Innovation Solution
The use of an annealed metal oxide etch stop layer, such as hafnium oxide or aluminum oxide, which is resistant to wet etching, formed by depositing and annealing the metal oxide material at a lower temperature and for a shorter time compared to silicon nitride, reducing etch rate and preventing erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etch stop layers (silicon nitride) are used, then etch selectivity is achieved, but the etch stop layer is eroded during wet etching causing etchant permeation and damage to underlying layers
Solution Approach 1:
The patent changes the material composition of the etch stop layer from silicon nitride to annealed metal oxide (such as hafnium oxide or aluminum oxide). This parameter change in material composition provides superior resistance to wet etchants while maintaining etch selectivity, preventing both erosion and etchant permeation that damage underlying layers
Solution Approach 2:
The patent employs composite material structure by forming an annealed metal oxide layer that combines the properties of metal oxide materials with controlled annealing treatment. This composite approach creates a etch stop layer that simultaneously achieves high etch selectivity and superior resistance to wet etching, resolving the contradiction between protection capability and structural integrity
2Reliability
If silicon nitride etch stop layer is used, then etch selectivity is provided, but high temperature and long time annealing is required compared to metal oxide
Solution Approach 1:
The patent changes the material parameter from silicon nitride to metal oxide, which fundamentally alters the annealing characteristics. Metal oxide materials require lower temperature and shorter time annealing to achieve the desired etch stop performance, directly reducing the thermal processing time and temperature budget compared to silicon nitride
3Reliability
If silicon nitride etch stop layer is used, then etch selectivity is achieved, but high energy consumption is required for high temperature and long time annealing
Solution Approach 1:
The patent changes the material composition to metal oxide, which requires lower temperature and shorter duration annealing treatment. This parameter change in material properties directly reduces the energy consumption for annealing while maintaining or improving the etch stop performance, as metal oxide materials achieve the required properties with less thermal energy input
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 annealed metal oxide etch stop layer effectively prevents etchant permeation, enhancing device reliability and yield by maintaining structural integrity during the etching process.
Implementation Method 1
annealing the deposited metal oxide material to obtain an annealed metal oxide layer which is substantially resistant to wet etching
Data Source
AI summary
An etch stop layer is formed over a first structure by depositing a metal oxide material over the first structure and annealing the deposited metal oxide material. A second structure is formed over the etch stop layer, and a formation is etched through the second structure using the etch stop layer as an etch stop.