Polysilicon Stopper Film CMP Scratch Reduction
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Solution Overview
Problem
The existing CMP process using silicon nitride films as stopper films requires additional processing steps for removal and often results in increased scratches on the polysilicon film, leading to potential device performance deterioration.
Innovation Solution
A method involving a silicon film as the stopper film with a surface modification film and a slurry containing cerium oxide particles, surface active agents, and resin particles with cationic or anionic functional groups for chemical mechanical polishing, which reduces scratches and eliminates the need for silicon nitride film removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a silicon nitride film is used as a stopper film, then the detection performance and surface state after polishing are improved, but the number of processes increases due to the need to remove the silicon nitride film
Solution Approach 1:
The invention extracts and removes the silicon nitride film from the process, replacing it with a polysilicon film that serves as the stopper film. This eliminates the need for additional removal processes while maintaining the essential function of automatic polishing termination detection.
Solution Approach 2:
The polysilicon film is designed to serve multiple functions: it acts as the stopper film for automatic detection of polishing timing, provides a good surface state after polishing, and eliminates the need for separate removal processes. This multi-functionality resolves the contradiction between detection performance and process complexity.
2Device complexity
If a polysilicon film is used as a stopper film without a silicon nitride film, then the number of processes is reduced, but scratches on the polysilicon film surface increase due to frequent rubbing by abrasive particles
Solution Approach 1:
The invention uses a composite slurry system containing cerium oxide particles for polishing, surface active agents for surface modification, and resin particles with cationic or anionic functional groups for protection. This composite approach reduces scratches on the polysilicon film while maintaining polishing effectiveness.
Solution Approach 2:
The surface active agents and resin particles act as intermediaries between the abrasive particles and the polysilicon film surface. These intermediaries reduce direct contact and mechanical damage from abrasive particles, thereby reducing scratches while maintaining the stopper film function.
3Ease of manufacture
If a polysilicon film is used as a stopper film, then the process is simplified, but device performance deteriorates due to increased scratches on the surface
Solution Approach 1:
The composite slurry containing cerium oxide particles, surface active agents, and resin particles with functional groups works together to simplify the process while protecting device performance. The resin particles and surface active agents specifically reduce scratches that would otherwise deteriorate device performance.
Solution Approach 2:
The invention changes the chemical and physical parameters of the polishing slurry by incorporating surface active agents and resin particles with specific functional groups. These parameter changes reduce the harmful effects of abrasive rubbing while maintaining process simplicity and polysilicon film functionality.
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 effectively planarizes silicon oxide films, reduces scratches on the polysilicon film, and simplifies the manufacturing process by eliminating the need for additional processing steps, thereby improving semiconductor device performance and reducing costs.
Implementation Method 1
forming a surface modification film for hydrophilizing a surface of the polysilicon film
Implementation Method 2
chemical mechanical polishing of the second silicon oxide film using slurry containing cerium oxide particles
Implementation Method 3
slurry for the chemical mechanical polishing contains cerium oxide particles, a surface active agent, and resin particles
Implementation Method 4
resin particles having a cationic or anionic functional group
Data Source
AI summary
In a method of manufacturing a semiconductor device for planarizing a silicon oxide film with chemical mechanical polishing using a silicon film formed on a semiconductor substrate as a stopper film, a surface modification film for hydrophilizing the surface of the silicon film is formed on an upper layer of the polysilicon film, and slurry for the chemical mechanical polishing contains cerium oxide particles, a surface active agent, and resin particles having a cationic or anionic functional group.