Light-Transmitting Polishing Pad for CMP Rate Control
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Solution Overview
Problem
The chemical mechanical polishing (CMP) process lacks the ability to adjust the polishing rate effectively, which is crucial for planarizing various substrate materials such as interlayer dielectric, silicon oxide films, and copper wiring.
Innovation Solution
A polishing apparatus and method utilizing a light-transmitting polishing pad with a built-in light source unit emitting a specific wavelength band of light to excite photocatalyst particles in the slurry, generating reactive OH radicals that adjust the chemical reaction rate and thus the polishing rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional CMP process is used, then the substrate surface can be planarized, but the polishing rate cannot be adjusted effectively
Solution Approach 1:
The patent applies parameter changes by introducing light irradiation as a controllable parameter to activate photocatalyst particles in the slurry. By adjusting light intensity, wavelength, and irradiation time, the polishing rate can be precisely controlled without sacrificing productivity. The chemical reaction rate is modified through optical parameter adjustment rather than mechanical or chemical composition changes.
Solution Approach 2:
The patent replaces part of the mechanical polishing system with a photochemical system. Instead of relying solely on mechanical abrasion, the invention uses light-activated photocatalyst particles to generate chemical reactions that assist the polishing process. This substitution enables independent control of chemical reaction rate through optical parameters, providing adjustable polishing rates while maintaining high productivity.
2Productivity
If the polishing rate is increased to improve productivity, then more materials can be processed, but control over the polishing rate is lost
Solution Approach 1:
The patent implements feedback control through the photochemical system. The light source parameters (intensity, wavelength, duration) can be precisely controlled and adjusted in real-time based on polishing requirements. This allows the polishing rate to be dynamically optimized for both high productivity and precise control, as the chemical reaction rate responds directly to controllable optical input parameters.
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
Enables precise control over the polishing rate by varying the amount of reactive OH radicals formed, enhancing the CMP process's efficiency and adaptability for different substrate materials.
Implementation Method 1
a slurry supply unit configured to supply a slurry containing photocatalyst particles excited by light of a predetermined wavelength band
Implementation Method 2
a polishing pad formed of a light-transmitting material
Implementation Method 3
a platen on which the polishing pad is disposed on an upper surface thereof, the platen having a groove portion in a region overlapping the polishing pad, and being rotatably installed in one direction
Data Source
AI summary
A polishing apparatus for a substrate, includes: a polishing pad having at least one region formed of a light-transmitting material; a platen on which the polishing pad is disposed on an upper surface thereof, having a groove portion in a region overlapping the polishing pad, and rotatably installed in one direction; a light source unit accommodated in the groove portion of the platen, and emitting light of a predetermined wavelength band to the one region of the polishing pad; a slurry supply unit supplying a slurry containing photocatalyst particles excited by the light of the predetermined wavelength band to the polishing pad; and a polishing head installed on the polishing pad to be spaced apart from the slurry supply unit in the one direction, and rotating a semiconductor substrate in close contact with the polishing pad.