Silicon Nitride Film for Semiconductor CMP Scratch Protection
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Solution Overview
Problem
The mechanical strength of semiconductor devices decreases when gaps are formed between interconnects, leading to damage during chemical mechanical polishing (CMP) due to scratches that can penetrate through insulating films, and existing blind CMP technologies cannot completely eliminate these scratches.
Innovation Solution
A method for manufacturing semiconductor devices that involves forming a silicon nitride film with compressive stress above the insulating film, which acts as a harder stopper film during CMP, preventing scratches from propagating to lower layers and maintaining the integrity of the device structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gaps are formed between interconnects to suppress electrical interference, then electrical isolation is improved, but mechanical strength decreases leading to damage during CMP
Solution Approach 1:
A silicon nitride film is formed in advance on the insulating film before CMP processing. This preliminary action creates a protective layer that prevents scratches from propagating to the underlying insulating film and electrode structures during subsequent CMP, thereby protecting the mechanically weakened structure while maintaining electrical isolation benefits
Solution Approach 2:
The silicon nitride film acts as an intermediary protective layer between the CMP polishing head and the underlying insulating film. This intermediate layer absorbs the mechanical stress and prevents direct contact between the polishing abrasives and the vulnerable insulating film, resolving the contradiction between electrical isolation and mechanical strength
2Manufacturing precision
If conventional CMP processing is used on structures with gaps, then planarization is achieved, but scratches penetrate through insulating films causing damage
Solution Approach 1:
The silicon nitride film is deposited beforehand to provide a cushioning protective layer that prevents scratch propagation. This prior cushioning absorbs the harmful mechanical effects of CMP processing before they can reach and damage the underlying insulating film and electrode structures
Solution Approach 2:
The silicon nitride film, which has inherently different mechanical properties including higher hardness and compressive stress, is used to convert the harmful scratch-propagation effect into a beneficial protective mechanism. The film's compressive stress state actually helps prevent crack initiation and propagation during CMP, turning a potential weakness into a protective feature
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 use of a silicon nitride film with compressive stress effectively blocks scratch propagation, preventing damage to the semiconductor device during CMP and ensuring high yield and reliability by maintaining the structural integrity of the device.
Implementation Method 1
forming a silicon nitride film having compressive stress above the insulating film
Data Source
AI summary
According to one embodiment, a method for manufacturing a semiconductor device includes forming a plurality of electrode structures above a substrate. The method includes forming an insulating film on the plurality of electrode structures to make a gap between mutually-adjacent electrode structures. The method includes forming a silicon nitride film having compressive stress above the insulating film. The method includes forming a planarization film above the silicon nitride film. The method includes planarizing a surface of the planarization film by polishing by CMP (chemical mechanical polishing) method.