MIM Capacitor Upper Electrode Protection During Etching
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Solution Overview
Problem
In semiconductor devices with MIM structures, forming openings for contact with the lower electrode without etching the upper electrode is challenging due to the thickness and etching time limitations of the interlayer insulating film, leading to potential capacitor leakage or incomplete contact.
Innovation Solution
A semiconductor device with a capacitance film and a protective film of the same material, where the protective film covers the upper electrode and is thicker than the portion of the capacitance film with the opening, allowing for reliable formation of openings in both films without etching the upper electrode by controlling the etching time and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the interlayer insulating film is increased to prevent etching of the upper electrode, then the upper electrode is protected from etching damage, but ions and radicals cannot successfully reach the capacitance film surface and the opening cannot be formed
Solution Approach 1:
The patent divides the protective function into two separate layers: the interlayer insulating film (first thickness) provides general protection, while the additional protective film (second thickness) specifically protects the upper electrode during etching. This segmentation allows each layer to have optimized thickness for its specific function, resolving the contradiction between protection and etching access.
Solution Approach 2:
The protective film is formed on the upper electrode before the etching process. This preliminary action ensures that the upper electrode is pre-protected with a sufficient thickness barrier, allowing the etching process to reach the capacitance film without damaging the upper electrode, thus resolving the timing and thickness conflict.
2Ease of manufacture
If the etching time is extended to ensure opening formation in the capacitance film, then complete contact is achieved, but the upper electrode may be excessively etched or pierced
Solution Approach 1:
The protective film is deposited on the upper electrode before the etching process begins. This preliminary protective layer acts as a barrier that allows longer etching times to be used safely, ensuring the opening is fully formed in the capacitance film while preventing excessive etching or piercing of the upper electrode.
Solution Approach 2:
The protective film serves as a cushioning layer that absorbs the excessive etching action. By providing this beforehand cushioning, the system can tolerate longer etching times needed for complete opening formation without the harmful effect of upper electrode damage, thus resolving the time conflict.
3Ease of manufacture
If the thickness of the capacitance film is reduced to facilitate opening formation, then etching can reach through more easily, but the capacitance density and performance are compromised
Solution Approach 1:
The patent segments the protective function from the capacitance function by adding a separate protective film layer. This allows the capacitance film to maintain its optimal thickness for performance while the protective film provides the additional thickness needed for successful etching penetration, resolving the thickness conflict between manufacturability and performance.
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 ensures reliable formation of openings in the capacitance film and protective film without etching the upper electrode, preventing capacitor leakage and ensuring proper contact between electrodes.
Implementation Method 1
When the capacitance film 93 is dry-etched, for example, ions and radicals do not successfully reach the surface of the capacitance film 93
Implementation Method 2
ions and radicals do not successfully reach the surface of the capacitance film 93
Implementation Method 3
a capacitance film 93 made of SiN (silicon nitride) and a metal film 94 made of TiN (titanium nitride) are laminated on the interlayer insulating film 91
Implementation Method 4
a capacitance film 93 made of SiN (silicon nitride) and a metal film 94 made of TiN (titanium nitride) are laminated on the interlayer insulating film 91
Data Source
AI summary
The semiconductor device according to the present invention includes a lower electrode made of a metallic material, a capacitance film made of an insulating material and laminated on the lower electrode, an upper electrode made of a metallic material, opposed to the lower electrode through the capacitance film, and having an outline smaller than that of the lower electrode in plan view along the opposed direction, and a protective film made of the same material as that of the capacitance film and laminated on the upper electrode.