Post-Etch Treating Method for Semiconductor Opening Cleaning
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Solution Overview
Problem
The necking phenomenon occurs during the cleaning process for removing etching residues in semiconductor manufacturing, causing corrosion of dielectric layers and aggravating tensile stress, which affects the formation of subsequent layers and increases contact and sheet resistance in metal-filled openings.
Innovation Solution
A post-etch treating method involving a first cleaning process to remove part of the metal hard mask layer, followed by a second cleaning process using a fluorine-containing solution, optionally preceded by a pre-cleaning process and followed by sputtering to reduce the aspect ratio and alleviate necking, facilitating the deposition of barrier and seed layers and reducing metal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cleaning process is performed to remove etching residues, then etching residues are removed, but the dielectric layer is corroded and necking phenomenon occurs
Solution Approach 1:
The cleaning process is divided into multiple sequential cleaning processes with different cleaning solutions. The first cleaning process uses a first cleaning solution to remove etching residues, and the second cleaning process uses a second cleaning solution to remove remaining residues. This segmentation allows each cleaning solution to be optimized for specific residues without excessive corrosion of the dielectric layer.
Solution Approach 2:
Different parameters of the cleaning solution are changed between processes, including the type of cleaning solution (first vs. second cleaning solution), concentration, and cleaning conditions. These parameter changes enable effective removal of etching residues while controlling the corrosion rate and preventing necking phenomenon.
2Strength
If the metal hard mask layer is present during cleaning, then it provides structural support, but it causes high tensile stress that aggravates necking phenomenon
Solution Approach 1:
A pre-cleaning process is performed before the main cleaning processes to remove etching residues on the metal hard mask layer. This preliminary action reduces the need for aggressive cleaning that would cause necking, while the metal hard mask layer still provides structural support during this gentler pre-cleaning step.
Solution Approach 2:
The metal hard mask layer serves as a cushioning layer during the pre-cleaning process, protecting the dielectric layer from direct exposure to aggressive cleaning solutions. This beforehand protection reduces tensile stress and prevents necking phenomenon while still allowing effective cleaning.
3Productivity
If a single cleaning process is used, then the process is simple and fast, but it cannot effectively remove all etching residues without corroding the dielectric layer
Solution Approach 1:
The cleaning process is segmented into multiple sequential processes, each targeting specific types of etching residues. The first cleaning process removes organic residues, while the second cleaning process removes inorganic residues. This segmentation achieves thorough cleaning without requiring excessively aggressive conditions that would corrode the dielectric layer.
Solution Approach 2:
The metal hard mask layer acts as an intermediary that protects the dielectric layer during the cleaning process. By performing cleaning steps that selectively remove etching residues while the metal hard mask layer provides protection, the dielectric layer integrity is maintained while achieving effective residue removal.
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 method effectively alleviates the necking phenomenon, increasing the process window for deposition and reducing contact and sheet resistance of metals like copper in the openings.
Implementation Method 1
performing a first cleaning process on the stacked structure with the opening so as to remove at least a part of the metal hard mask layer
Implementation Method 2
performing a second cleaning process on the stacked structure with the opening so as to remove etching residues
Implementation Method 3
followed by sputtering to reduce the aspect ratio
Data Source
AI summary
This disclosure relates to a post-etch treating method. An opening is formed by etching a stacked structure of a dielectric layer, an intermediate layer and a metal hard mask layer arranged in order from bottom to top. The treating method sequentially comprises steps of: performing a first cleaning process on the stacked structure with the opening so as to remove at least a part of the metal hard mask layer; and performing a second cleaning process on the stacked structure with the opening so as to remove etching residues.