Conductive Solution Rinse for Post-Etch Residue Removal
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Solution Overview
Problem
In semiconductor manufacturing, post-etch residues on dielectric layers can cause arcs when removed by cleaning solutions, leading to damage of semiconductive elements due to charge accumulation during the etching process in copper damascene interconnect processes.
Innovation Solution
A method involving a conductive solution with deionized water and conductive ions like bicarbonate, carbonate, or ammonium ions is used to rinse the patterned hard mask and dielectric layer, neutralizing accumulated charges before a cleaning solution is applied to remove post-etch residues, preventing arcs by ensuring the cleaning solution can contact the surface without causing electrical discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cleaning solution is used to remove post-etch residues, then the residues are removed, but arcs form due to charge accumulation on the dielectric layer
Solution Approach 1:
The patent applies preliminary action by introducing a conductive solution rinse step before the cleaning solution application. This preliminary rinse removes accumulated charges from the dielectric layer surface, preventing arcs when the cleaning solution is subsequently applied. The conductive solution temporarily prepares the surface by neutralizing charges, allowing the main cleaning process to proceed without harmful electrical discharges.
Solution Approach 2:
The conductive solution acts as an intermediary between the charged dielectric layer and the cleaning solution. It serves as a mediating substance that safely dissipates accumulated charges through its ionic conductivity, bridging the harmful charged surface and the cleaning process. This intermediary step transfers the charge removal function, enabling the cleaning solution to work without causing arcs.
2Manufacturing precision
If deionized water is used to rinse the dielectric layer, then it is effective for removing residues, but it cannot conduct away accumulated charges
Solution Approach 1:
The patent applies parameter changes by modifying the electrical conductivity parameter of the rinsing solution. Instead of using pure deionized water with very high resistance, the invention introduces conductive ions (such as ammonium bicarbonate, ammonium carbonate, or a combination) to adjust the solution's resistance to a specific range (1-3000 MΩ·cm). This parameter adjustment enables the solution to simultaneously maintain residue removal effectiveness and gain charge conduction capability.
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 approach effectively prevents arcs during the removal of post-etch residues, ensuring the integrity of semiconductive elements by conducting charges away from the dielectric layer, thereby safeguarding against damage from electrical discharges during the cleaning process.
Implementation Method 1
The solution conducts the accumulated charges to leave the patterned hard mask and the dielectric layer
Implementation Method 2
an etching process is performed to etch the hard mask with ions so as to form a patterned hard mask
Data Source
AI summary
A method of removing post-etch residues is provided. First, a substrate is provided. An isolation layer covers the substrate and a conductive layer is embedded in the isolation layer. A dielectric layer and a hard mask cover the isolation layer. Then, an etching process is performed, and a patterned hard mask is formed by etching the hard mask by ions or atoms. After that, a charge-removing process is performed by using a conductive solution to cleaning the patterned hard mask and the dielectric layer so as to remove the charges accumulated on the patterned hard mask and the dielectric layer during the etch process. Finally, the post-etch residues on the patterned hard mask and the dielectric layer is removed.