Hypobromite Ruthenium Etchant With pH Buffering for Stable Wafer Processing
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Solution Overview
Problem
Existing semiconductor treatment liquids for etching ruthenium lack precision control over the etching rate and stability, leading to issues such as non-uniform etching and potential exposure of other wiring materials, which can cause current leakage and incorrect semiconductor element operation.
Innovation Solution
A semiconductor treatment liquid containing hypobromite ions, a pH buffer, and onium ions, optionally with bromide, bromite, and/or bromate ions, to stabilize the pH and concentration of hypobromite ions, ensuring precise and stable etching of ruthenium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a treatment liquid containing only hypobromite ion is used, then the etching rate of ruthenium is high, but the pH and hypobromite ion concentration fluctuate significantly, making it difficult to control the etching amount
Solution Approach 1:
The invention changes the chemical parameters of the treatment liquid by introducing a pH buffer system (maintaining pH 10-12) and controlling hypobromite ion concentration within specific ranges (10^-6 to 10^-1 mol/L). These parameter controls stabilize the etching process while maintaining high etching rates, resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The invention introduces intermediary substances (pH buffers and stabilizing agents) that mediate between the hypobromite ion and ruthenium. These intermediaries maintain stable pH and ion concentration levels, preventing fluctuations that would otherwise cause imprecise etching control while preserving the high etching capability.
2Device complexity
If a treatment liquid containing only hypobromite ion is used, then the etching process is simple, but the stability of the treatment liquid is poor
Solution Approach 1:
The invention creates a composite treatment liquid system combining hypobromite ions with pH buffers and stabilizing agents. This composite formulation enhances the stability and reliability of the treatment liquid while maintaining relative simplicity in composition and application procedure.
3Productivity
If the etching rate is not controlled precisely, then the etching process is fast, but other wiring materials may be exposed causing current leakage and incorrect operation
Solution Approach 1:
By precisely controlling pH (10-12) and hypobromite ion concentration (10^-6 to 10^-1 mol/L), the invention maintains a stable etching rate that is both fast and controllable. This prevents over-etching that would expose underlying wiring materials, thereby ensuring operational reliability while preserving high productivity.
Solution Approach 2:
The invention establishes a feedback mechanism through pH buffering and ion concentration control, where the treatment liquid automatically maintains stable chemical conditions during etching. This feedback system ensures consistent etching rates that prevent damage to underlying structures while maintaining high processing 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
The treatment liquid maintains a consistent etching rate and improves stability, allowing for precise control of ruthenium etching without damaging the semiconductor wafer, thereby ensuring reliable semiconductor manufacturing.
Implementation Method 1
A semiconductor treatment liquid containing: (A) a hypobromite ion... The treatment liquid maintains a consistent etching rate and improves stability, allowing for precise control of ruthenium etching
Implementation Method 2
the purpose of the treatment liquid is to remove ruthenium adhered to the substrate such as the semiconductor wafer... adding onium ions and a pH buffer to the treatment liquid containing a hypobromite ion can reduce fluctuations in the pH of the treatment liquid
Data Source
AI summary
Provided is a treatment liquid for treating a semiconductor wafer in a semiconductor forming process, the treatment liquid containing (A) a hypobromite ion, (B) a pH buffer, and (C) an onium ion represented by formula (1):(wherein R1, R2, R3, and R4 each independently denote an alkyl group having carbon number from 1 to 25,)