CMP Slurry Photocatalyst Light Irradiation Uniformity
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Solution Overview
Problem
The chemical mechanical polishing (CMP) process faces challenges in maintaining uniformity and material removal rate (MRR) on larger semiconductor wafers, leading to increased processing time and substrate rejection due to variability in polishing pad wear and slurry composition.
Innovation Solution
Incorporating a photocatalyst in the CMP system that reacts with light to generate oxidative radicals, such as hydroxyl radicals, in the slurry or solution, increasing the material removal rate and allowing for real-time adjustment of light intensity to maintain consistent substrate thickness without extending processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafer size is increased to improve throughput and reduce cost per die, then productivity increases, but manufacturing precision deteriorates due to difficulty in maintaining uniformity in smoothness and thickness
Solution Approach 1:
The patent applies local quality by varying the slurry flow rate across different regions of the polishing pad. Specifically, the slurry flow rate is increased at the center region and decreased at the edge regions of the polishing pad. This localized adjustment compensates for the non-uniform polishing characteristics that occur on large wafers, ensuring consistent material removal rate and surface uniformity across the entire wafer surface.
2Area of stationary object
If conventional CMP process is used on larger wafers, then processing area increases, but manufacturing precision deteriorates due to variability in polishing pad wear and slurry composition
Solution Approach 1:
The patent implements dynamics by dynamically adjusting the slurry flow rate during the CMP process. The system continuously monitors polishing conditions and modifies the slurry delivery in real-time, increasing flow to the center region and decreasing it at the edges. This dynamic control compensates for variations in polishing pad wear and slurry composition, maintaining uniform polishing quality across the large wafer surface area.
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 consistent substrate thickness and MRR, reducing substrate rejection and processing time by enhancing the CMP process's efficiency and uniformity through the use of photocatalytic reactions.
Implementation Method 1
Incorporating a photocatalyst in the CMP system that reacts with light to generate oxidative radicals, such as hydroxyl radicals, in the slurry or solution
Data Source
AI summary
A chemical-mechanical planarization device and a method for using a chemical-mechanical planarization device in conjunction with a semiconductor substrate is provided. In accordance with some embodiments, the device includes: a pad disposed over a rotatable platen; a carrier head disposed over the pad and configured to retain a semiconductor substrate between the pad and the carrier head; a tank configured to retain a liquid containing composition; at least one tube fluidly coupled with the tank, the at least one tube comprising a photocatalyst therein; a nozzle fluidly coupled with the tank through the at least one tube and configured to supply the liquid containing composition onto the pad; and a light source configured to provide light to irradiate the photocatalyst, and the liquid containing composition passing through the at least one tube.