CMP Slurry Passivation for Pattern Density Planarization
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Solution Overview
Problem
The challenge in semiconductor device manufacturing is achieving overall planarization during chemical mechanical polishing (CMP) of substrates with areas of different pattern densities, as the CMP process often results in over-polishing of high-density areas and under-polishing of low-density areas, leading to operational errors.
Innovation Solution
A polishing slurry composition containing a polishing agent, a silicon nitride film passivation agent, and a silicon film passivation agent is used, where the silicon nitride film passivation agent reduces the polishing rate on high-density areas and the silicon film passivation agent prevents further polishing of exposed silicon films, ensuring global planarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional CMP process is used to planarize the substrate, then the polishing rate is high enough to remove material efficiently, but the pattern density effect causes over-polishing in high-density areas and under-polishing in low-density areas, failing to achieve global planarization
Solution Approach 1:
The patent applies local quality by introducing a silicon nitride film as an intermediate layer that provides different polishing characteristics to different areas. The silicon nitride film is formed selectively in regions where pattern density effects cause non-uniform polishing, creating local variations in film composition and polishing rate that compensate for the pattern density effect and achieve global planarization
Solution Approach 2:
The patent changes the physical and chemical parameters of the polishing system by controlling the thickness, composition, and physical state of the silicon nitride film. By adjusting these parameters, the polishing rate is modulated across different areas of the substrate, allowing high-density areas to be polished at different rates than low-density areas, thereby achieving uniform planarization
2Device complexity
If a single-layer structure is used, then the process is simple, but the pattern density effect cannot be compensated and global planarization cannot be achieved
Solution Approach 1:
The patent applies composite materials by creating a multi-layer film structure consisting of a silicon oxide film and a silicon nitride film. This composite structure combines the properties of both materials, where the silicon nitride film provides the necessary modulation of polishing rate to compensate for pattern density effects, while the silicon oxide film provides a base layer for planarization
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 solution effectively compensates for pattern density effects by reducing the polishing rate on high-density areas and preventing over-polishing, resulting in a globally planarized surface and facilitating the detection of the polishing end point.
Implementation Method 1
the silicon nitride film passivation agent contained in the polishing slurring composition forms a passivation film on the silicon nitride film exposed on the first area
Implementation Method 2
the silicon film passivation agent contained in the polishing slurry composition forms a passivation film on the silicon film
Implementation Method 3
a chemical mechanical polishing (CMP) process is performed using a polishing slurry composition containing a polishing agent
Data Source
AI summary
Provided are a multi-selective polishing slurry composition and a semiconductor element production method using the same. A silicon film provided with element patterns is formed on the uppermost part of a substrate having a first region and a second region. The element pattern density on the first region is higher than the element pattern density on the second region. Formed in sequence on top of the element patterns are a first silicon oxide film, a silicon nitride film and a second silicon oxide film. The substrate is subjected to chemical-mechanical polishing until the silicon film is exposed, by using a polishing slurry composition containing a polishing agent, a silicon nitride film passivation agent and a silicon film passivation agent. The polishing slurry composition may be a mixture of 100 parts by weight of a polishing agent suspension, containing a polishing agent, and from 40 to 120 parts by weight of an additive solution, and the additive solution can contain 100 parts by weight of a solvent, from 0.01 to 5 parts by weight of a silicon nitride film passivation agent and from 0.01 to 5 parts by weight of a silicon film passivation agent.