Substrate Processing Method for Metal Layer Etching
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Solution Overview
Problem
In the backend process of semiconductor device production, achieving precise etching of metal layers with nanometer accuracy is challenging due to the lengthy process of wet etching, which requires repeated etching cycles with high precision, increasing the overall time required for metal oxide layer formation and removal.
Innovation Solution
A substrate processing method and device that alternately perform metal oxide layer forming and removal processes using an oxidation fluid and etching solution, with a controller adjusting the dissolved oxygen concentration in the etching solution to reduce the final concentration, allowing for precise control of the etching amount and time, utilizing an oxidation fluid nozzle, etching solution tank, and dissolved oxygen concentration reducing unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet etching is performed repeatedly to achieve desired etching amount, then etching precision is improved, but processing time increases
Solution Approach 1:
The invention changes the chemical parameters of the etching solution by controlling dissolved oxygen concentration. By reducing dissolved oxygen concentration in subsequent etching steps, the etching rate is modulated to enable precise removal of metal oxide layers formed in previous oxidation steps, achieving atomic-layer precision without excessive processing time
Solution Approach 2:
The invention employs periodic alternation between oxidation steps and etching steps. During oxidation, metal surfaces are converted to metal oxide layers; during etching, these oxide layers are selectively removed. This periodic cycle allows precise control of etching depth by controlling the number of cycles and the dissolved oxygen concentration in each etching step
2Manufacturing precision
If dissolved oxygen concentration in etching solution is reduced, then etching selectivity is improved, but process complexity increases
Solution Approach 1:
The invention modifies the chemical composition parameter of the etching solution by controlling dissolved oxygen concentration. This is achieved through simple operational means such as purging with inert gas or controlling aeration, making the parameter change easy to implement without complex equipment
Solution Approach 2:
The invention implements a feedback control mechanism where the dissolved oxygen concentration in the etching solution is monitored and adjusted based on the etching progress. The controller regulates the oxidation and etching cycles, adjusting dissolved oxygen concentration in subsequent etching steps based on the metal oxide layer thickness formed in previous oxidation steps
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 significantly reduces the time required for metal oxide layer processing while maintaining high accuracy in etching metal layers, improving etching selectivity and surface flatness, and allowing for precise control of the etching amount, enabling efficient and accurate processing of substrates with metal layers.
Implementation Method 1
a metal oxide layer forming process in which an oxidation fluid is supplied to a surface of the substrate and a metal oxide layer composed of a one-atom layer or a several-atom layer is formed on a surface layer of the metal layer
Implementation Method 2
a metal oxide layer removal process in which an etching solution is supplied to the surface of the substrate and the metal oxide layer is removed from the surface of the substrate
Data Source
AI summary
The substrate processing method includes alternately performing a plurality of times of a metal oxide layer forming process in which an oxidation fluid is supplied to a surface of the substrate and a metal oxide layer composed of a one-atom layer or a several-atom layer is formed on a surface layer of the metal layer; and a metal oxide layer removal process in which an etching solution is supplied to the surface of the substrate and the metal oxide layer is removed from the surface of the substrate. A final dissolved oxygen concentration which is a dissolved oxygen concentration in the etching solution supplied to the surface of the substrate in a final metal oxide layer removal process is lower than an initial dissolved oxygen concentration which is a dissolved oxygen concentration in the etching solution supplied to the substrate in an initial metal oxide layer removal process.