Conductive Fill Adhesion via Seed Layer Oxide Removal
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving efficient conductive interconnects due to the presence of thin cobalt oxide layers, which impede current conduction and lead to gaps, oxide pockets, and adhesion failures in ultra-small cross-sectional areas, affecting the performance and miniaturization of integrated circuits.
Innovation Solution
A surface treatment process is employed to reduce or eliminate the oxide layer on the seed layer, followed by a hydroxylating step to improve wettability, allowing for the deposition of a conductive fill using electrochemical plating, thereby enhancing the adhesion and reducing defects and resistivity of the conductive interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive fill is deposited over a seed layer without surface treatment, then the deposition process is simple and fast, but the oxide layer on the seed layer impedes current conduction and causes defects
Solution Approach 1:
The patent applies preliminary surface treatment actions (vacuum treatment to remove oxide layer, followed by hydroxylating treatment to create hydroxyl groups) before the conductive fill deposition. This preliminary preparation of the seed layer surface ensures proper adhesion and electrical conduction, resolving the contradiction by accepting increased process complexity in exchange for reliable electrical performance.
2Manufacturing precision
If the minimum feature size is reduced to increase planar density, then more electronic components can be placed at any given level, but the oxide layer defects become more prevalent in ultra-small cross-sectional areas
Solution Approach 1:
The patent applies local quality treatment by specifically treating the seed layer surface at the interface where conductive fill will be deposited. The vacuum and hydroxylating treatments are applied locally to the seed layer surface in the openings, creating optimal adhesion conditions precisely where needed in ultra-small cross-sectional areas, thus maintaining reliability despite feature size reduction.
3Strength
If electrochemical plating is used to deposit conductive fill, then good adhesion can be achieved, but the presence of oxide layers prevents proper bonding and increases resistivity
Solution Approach 1:
The patent applies preliminary anti-action by using vacuum treatment to remove the harmful oxide layer and hydroxylating treatment to create a surface with hydroxyl groups that are receptive to conductive fill bonding. This preliminary elimination of the oxide barrier enables the electrochemical plating to achieve strong adhesion and low resistivity, resolving the contradiction between achieving good adhesion and eliminating oxide interference.
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 significantly reduces defects and resistivity, improving the electrical performance and miniaturization capabilities of integrated circuits by ensuring better bonding and conductivity of the conductive fills in the interconnects.
Implementation Method 1
The seed layer may then be treated with a vapor process to hydroxylate and/or moisturize the seed layer
Implementation Method 2
The seed layer is treated to remove an oxide of the first material
Implementation Method 3
The seed layer is treated with a vapor process to hydroxylate and/or moisturize the seed layer
Implementation Method 4
A conductive fill is deposited over the hydrolyzed seed layer
Data Source
AI summary
A conductive fill is provided in an opening of an interconnect layer. A seed layer is formed, a portion of which is then oxidized. The oxygen is removed in a treatment process and the surface of the de-oxidized seed layer is hydrolyzed to form a hydroxyl sublayer and moisturized. The conductive fill is formed over the hydroxyl sublayer.