MIM Capacitor Top Electrode Sidewall Damage Prevention
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Solution Overview
Problem
The formation of metal-insulator-metal (MIM) capacitors is challenged by sidewall damage to the top and bottom electrodes during the photoresist wet strip processes, leading to reduced dimensions and capacitance due to erosion of aluminum copper layers.
Innovation Solution
A method is developed where the top electrode is formed without aluminum copper, using a different material such as titanium nitride, and etched separately from the bottom electrode, avoiding sidewall damage and ensuring uniform dimensions and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the top electrode is formed with aluminum copper material, then the electrode can be patterned with photolithography, but the sidewalls are eroded during photoresist wet strip processes reducing dimensions and capacitance
Solution Approach 1:
The patent extracts the problematic aluminum copper material from the top electrode formation, using only titanium nitride and other erosion-resistant materials instead. This eliminates the sidewall erosion issue during photoresist wet strip processes while maintaining the ability to pattern the electrode with photolithography.
Solution Approach 2:
The patent uses a composite material structure for the top electrode consisting of titanium nitride combined with other erosion-resistant materials, replacing the single aluminum copper material. This composite approach provides both photolithography patternability and resistance to photoresist wet strip erosion.
2Productivity
If the top and bottom electrodes are etched together in a single process, then the manufacturing process is simplified, but the top electrode suffers sidewall damage from the etch process
Solution Approach 1:
The patent segments the etching process into two separate operations: first etching the top electrode, then etching the bottom electrode. This segmentation allows the top electrode to be etched under optimized conditions without exposure to the bottom electrode etching process, preventing sidewall damage while maintaining manufacturing efficiency.
Data Source
AI summary
A method for manufacturing a metal-insulator-metal (MIM) capacitor with a top electrode that is free of sidewall damage is provided. A bottom electrode layer is formed with a first material. An inter-electrode dielectric layer is formed over the bottom electrode layer. A top electrode layer is formed over the inter-electrode dielectric layer and without the first material. A first etch is performed into the top electrode layer and the inter-electrode dielectric layer to form a top electrode. A second etch into the bottom electrode layer to form a bottom electrode. The present application is also directed towards a MIM capacitor resulting from performing the method.