Dual Plasma Pre-Clean for Interconnects to Remove Metal Contaminants
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pre-clean processes for interconnect structures in semiconductor devices can damage the patterned dielectric material, leading to reduced device performance and reliability, particularly due to the challenge of controlling the removal of metal compounds like copper oxides without harming the surrounding dielectric layer.
Innovation Solution
A method involving two plasma treatment processes is employed: the first enriches the dielectric surface with specific elements and the second, with reduced plasma ion density, specifically removes metal contact products like copper compounds from the substrate contact area without damaging the dielectric material, using processes such as silylation, oxidation, or nitridation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pre-clean process is used to remove metal compounds from the substrate, then metal compounds like copper oxides are removed, but the patterned dielectric material is damaged
Solution Approach 1:
The pre-clean process is divided into two distinct plasma treatment steps: a first plasma treatment that selectively removes metal compounds from the substrate contact area, and a second plasma treatment that protects and cleans the dielectric material surface. This segmentation allows each step to be optimized for its specific function, preventing dielectric damage while effectively removing metal contaminants.
Solution Approach 2:
The first plasma treatment is applied selectively to the opening region where metal compounds are present, while the second plasma treatment is applied to the dielectric material surfaces. This localized application ensures that metal removal occurs only where needed without exposing the dielectric material to damaging conditions, thereby maintaining dielectric integrity while achieving effective cleaning.
2Reliability
If a strong plasma treatment is used to remove metal compounds, then cleaning effectiveness is improved, but dielectric material damage increases
Solution Approach 1:
The first plasma treatment is performed as a preliminary step to remove metal compounds from the substrate contact area before the dielectric material is exposed to any potentially damaging treatments. This preliminary cleaning action ensures that metal contaminants are eliminated while the dielectric material remains protected, establishing a clean interface for subsequent metallization processes.
Solution Approach 2:
The patent employs different plasma treatment parameters for the two steps: the first plasma treatment uses conditions optimized for metal compound removal, while the second plasma treatment uses milder conditions that clean the dielectric surface without causing damage. By changing plasma parameters (such as power, gas composition, and treatment duration) between steps, the process achieves effective cleaning while preventing dielectric degradation.
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 enhances both the reliability and performance of semiconductor devices by effectively removing metal compounds without damaging the dielectric material, thereby improving signal transmission and reducing crosstalk between adjacent lines.
Implementation Method 1
performing a plasma treatment process to chemically enrich exposed surfaces of the dielectric material that line the opening
Implementation Method 2
chemically enrich exposed surfaces of the dielectric material to form a chemically-enriched dielectric surface layer
Implementation Method 3
performing a chemical treatment process to remove a metal contact product from the portion of the substrate that is in contact with the opening
Implementation Method 4
remove metal compounds like copper oxides
Data Source
AI summary
A method of making an interconnect structure includes forming an opening within a dielectric material layer disposed on a substrate including a conductive material, the opening extending from a first surface to a second surface of the dielectric material layer and being in contact with a portion of the substrate; performing a plasma treatment process to chemically enrich exposed surfaces of the dielectric material that line the opening to form a chemically-enriched dielectric surface layer that included an element in a higher concentration than a remaining portion of the dielectric material layer; performing a chemical treatment process to remove a metal contact product from the portion of the substrate that is in contact with the opening; and disposing a conductive material in the opening to substantially fill the opening and form the interconnect structure.