Stepped Dresser with Variable Superhard Particles for CMP Pad
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Solution Overview
Problem
The prolonged operating time of the dresser in chemical mechanical polishing (CMP) processes leads to wear and insufficient dressing of the polishing pad, resulting in defective polishing of semiconductor substrates.
Innovation Solution
A dresser with a stepped surface and superhard particles of increasing diameters, where the load applied to the dresser is adjusted to switch between different particle sizes based on operating time to maintain effective polishing, ensuring continuous dressing with fresh particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dresser operates for a prolonged period, then productivity is improved, but the dresser becomes worn and dressing quality deteriorates
Solution Approach 1:
The dresser surface is segmented into multiple stepped regions (first step, second step, third step) with different particle diameters. As the dresser operates, worn particles on upper steps are replaced by fresh particles from lower steps, maintaining consistent dressing quality over extended periods without requiring dresser replacement.
Solution Approach 2:
The dresser is pre-configured with multiple layers of particles of different diameters at different steps before operation begins. This preliminary arrangement ensures that as operation progresses and particles wear, the system automatically transitions to the next layer of particles, maintaining dressing effectiveness throughout the operational cycle.
2Manufacturing precision
If larger particles are used initially, then dressing effectiveness is improved, but particle wear occurs and polishing precision deteriorates over time
Solution Approach 1:
The dresser dynamically transitions between different particle sizes during operation. The system moves from larger particles on upper steps to progressively smaller particles on lower steps as operation continues, adapting the particle size to the wear state and maintaining optimal polishing precision throughout the particle service life.
Solution Approach 2:
The particle diameter parameter changes progressively across different steps of the dresser. By varying this critical parameter spatially across the stepped structure, the system maintains effective dressing and polishing quality over extended operational periods as particles wear and transition between steps.
3Device complexity
If the dresser structure is simplified, then device complexity is reduced, but the ability to maintain consistent dressing quality over time is compromised
Solution Approach 1:
The dresser employs a stepped structure that segments the surface into distinct levels, each populated with particles of specific diameters. This segmentation provides a simple yet effective mechanism for maintaining dressing consistency over time, avoiding complex control systems while ensuring quality reliability.
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 stabilizes the cut rate of the polishing pad, preventing a decrease in polishing efficiency and minimizing defective polishing by using progressively larger particles as the previous ones wear out.
Implementation Method 1
a plurality of superhard particles disposed on each of the plurality of steps of the stepped surface
Data Source
AI summary
A dresser includes a main body having a stepped surface comprising a plurality of steps, wherein a thickness of the main body at a first step of the plurality of steps is a largest thickness of the main body, and a thickness of the main body at a last step of the plurality of steps is a smallest thickness of the main body; and a plurality of superhard particles disposed on each of the plurality of steps of the stepped surface. The plurality of steps of the stepped surface are different in area, and particle diameters of the superhard particles increase stepwise from the first step of the plurality of steps to the last step of the plurality of steps.