Selective Cleaning of Post-Etch Residues in BEOL
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Solution Overview
Problem
There is a need for effective cleaning compositions that can selectively remove post-etch residue and aluminum-containing materials from microelectronic devices without damaging cobalt-containing layers, copper, or low-k dielectric materials, which are common in advanced semiconductor manufacturing processes.
Innovation Solution
Aqueous cleaning compositions comprising a metal corrosion inhibitor, etchant source, chelating agent, silica source, and oxidizing agent, specifically designed to have a controlled etch rate selectivity for aluminum-containing materials over other layers, allowing for efficient removal of post-etch residues and aluminum-containing etch stop layers while protecting cobalt, copper, and low-k dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cleaning chemistry is used to remove post-etch residue, then cleaning effectiveness is improved, but selectivity is worsened causing damage to cobalt-containing layers, copper, and low-k dielectric materials
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific corrosion inhibitors, chelating agents, and oxidizing agents in controlled concentrations. This changes the chemical reactivity parameters of the cleaning solution to achieve selective removal of post-etch residue while protecting sensitive materials like cobalt, copper, and low-k dielectrics through controlled etch rates.
Solution Approach 2:
The cleaning chemistry is formulated as a composite solution containing multiple functional components: corrosion inhibitors to protect metals, chelating agents to bind residual metals, oxidizing agents to remove organic residue, and buffers to control pH. This composite formulation enables simultaneous protection of multiple sensitive materials while maintaining effective cleaning.
2Productivity
If etch rate is increased to improve cleaning speed, then productivity is improved, but selectivity is worsened causing damage to protected layers
Solution Approach 1:
The patent optimizes the concentration parameters of active cleaning agents to achieve the desired etch rate. By controlling the amounts of oxidizing agents, chelating agents, and corrosion inhibitors, the process achieves high cleaning speed while maintaining selectivity through controlled chemical reactivity with different materials.
Solution Approach 2:
The cleaning process parameters including temperature, exposure time, and chemical concentration are dynamically optimized to achieve high cleaning speed while protecting sensitive materials. The process adapts the etch rate through controlled chemical reactions that progress differently on various materials.
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 compositions achieve at least 90% removal of post-etch residues and aluminum-containing materials while maintaining the integrity of cobalt, copper, and low-k dielectric layers, ensuring high selectivity and minimal damage during the cleaning process.
Implementation Method 1
a cleaning composition suitable for removing post-etch residues and aluminum-containing materials from a microelectronic device having same thereon
Implementation Method 2
comprising (a) a concentrate comprising, consisting of, or consisting essentially of at least one metal corrosion inhibitor, at least one etchant source, at least one silica source, at least one chelating agent, and at least one solvent, and (b) at least one oxidizing agent
Data Source
AI summary
The disclosure relates to a cleaning composition that aids in the removal of post-etch residues and aluminum-containing material, e.g., aluminum oxide, in the production of semiconductors that utilize an aluminum-containing etch stop layer. The compositions have a high selectivity for post-etch residue and aluminum-containing materials relative to low-k dielectric materials, cobalt-containing materials and other metals on the microelectronic device.