Capacitor Array Oxide-Nitride CMP for Uniform Endpoint Detection
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Solution Overview
Problem
The existing chemical mechanical polishing (CMP) process for forming capacitor arrays in semiconductor devices faces challenges with poor uniformity and inability to apply endpoint detection, leading to increased mean standard deviation and loss ranges, especially when removing thick oxide layers exceeding 10000 angstroms.
Innovation Solution
The method involves forming a top electrode plate in both active and periphery regions of a substrate, depositing a first oxide layer, removing the top electrode plate in the periphery region, forming a nitride film on the first oxide layer, depositing a second oxide layer, and polishing it to expose the nitride film, thereby improving CMP process uniformity and enabling endpoint detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thick oxide is removed through chemical mechanical polishing (CMP) process, then the oxide layer is removed, but the uniformity of CMP process deteriorates and mean standard deviation increases
Solution Approach 1:
The patent divides the capacitor array formation process into multiple stages: first forming a preliminary electrode plate structure, then performing CMP to remove thick oxide, and finally forming the precise top electrode plate. This segmentation allows the CMP process to operate on a controlled preliminary structure rather than directly on the final capacitor array, improving uniformity by reducing the loss range from 1000 angstrom to below 500 angstrom.
Solution Approach 2:
The patent performs preliminary actions by forming the preliminary electrode plate and depositing the first oxide layer before the final capacitor array formation. This preliminary structure serves as a foundation that enables better control during the CMP process, allowing endpoint detection to be effectively applied and improving overall manufacturing precision.
2Manufacturing precision
If thick oxide layer is processed, then complete removal is achieved, but endpoint detection cannot be applied
Solution Approach 1:
The patent segments the oxide layer into two parts: the first oxide layer deposited before capacitor array formation, and the second oxide layer deposited after. The CMP process primarily removes the first oxide layer, which has a controlled thickness that enables effective endpoint detection, while the second oxide layer is deposited afterward to achieve the final required thickness.
Solution Approach 2:
The patent performs preliminary deposition of the first oxide layer with controlled thickness before capacitor array formation. This preliminary oxide layer serves as the target for CMP removal with endpoint detection, enabling precise process control even when the total oxide thickness exceeds 10000 angstroms.
3Manufacturing precision
If additional etching back processes are used to improve uniformity, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent performs preliminary formation of the first oxide layer with optimized thickness and properties before capacitor array formation. This preliminary preparation enables the subsequent CMP process to achieve improved uniformity (reduced post-CMP mean standard deviation) without requiring additional etching back processes, thereby avoiding increased device complexity.
Solution Approach 2:
The patent changes the parameters of the first oxide layer (thickness, deposition conditions) to optimize the subsequent CMP process. By carefully controlling the first oxide layer parameters, the process achieves better uniformity and reduced post-CMP mean standard deviation without adding complex etching back steps.
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 enhances the uniformity of the CMP process, reduces post-CMP mean standard deviation, and allows for effective endpoint detection, even when processing thick oxide layers exceeding 10000 angstroms, without the need for additional etching back processes.
Implementation Method 1
the second oxide layer is polished to expose the nitride film in the active region
Implementation Method 2
a first oxide layer is deposited above the top electrode plate; a nitride film is formed on the first oxide layer; a second oxide layer is deposited on the nitride film
Data Source
AI summary
A method of forming a semiconductor device having a capacitor array includes forming a top electrode plate of the capacitor array in an active region and a periphery region of a substrate; depositing a first oxide layer above the top electrode plate in the active region and the periphery region; removing the top electrode plate in the periphery region; forming a nitride film on the first oxide layer in the active region and in the periphery region; depositing a second oxide layer on the nitride film in the active region and the periphery region; and polishing the second oxide layer to expose the nitride film in the active region.