Abrasive Articles with Precisely Shaped Features for Semiconductor Polishing
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Solution Overview
Problem
Current pad conditioners in the semiconductor industry face challenges such as irregular diamond grit distribution, limited size of embeddable diamonds, and chemical reactivity with acidic slurries, leading to reduced performance and increased wafer defectivity.
Innovation Solution
The development of an abrasive article comprising precisely shaped, monolithic carbide ceramic elements with at least 99% carbide content and low porosity, which are aligned and mounted on a carrier with a resilient element to ensure consistent and reproducible polishing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If natural diamond grit is used in traditional pad conditioners, then high abrasion capability is achieved, but irregular size and shape distributions lead to poor manufacturing precision and performance consistency
Solution Approach 1:
The patent changes the fundamental parameter of abrasive material from natural diamond to synthetic cubic boron nitride (cBN) particles, which can be manufactured with controlled size and shape parameters. This material substitution enables precise control over abrasive characteristics while maintaining high abrasion capability, directly resolving the contradiction between strength and manufacturing precision.
Solution Approach 2:
Instead of using natural diamond particles with random properties, the patent employs synthetic cBN particles that are created through controlled chemical vapor deposition processes. These synthetic particles replicate and improve upon natural diamond properties while achieving uniform size distribution (e.g., 10-50 μm ranges) and consistent spherical shapes, thereby enhancing manufacturing precision.
2Strength
If metal bonding matrix is used to hold diamond particles, then strong bonding is achieved, but chemical reaction with acidic slurries weakens the bond and causes metal ion contamination
Solution Approach 1:
The patent replaces traditional metal bonding matrices with a composite material system consisting of alumina (aluminum oxide) or silica (silicon dioxide) ceramic matrices. These materials provide strong mechanical bonding for the cBN particles while exhibiting chemical inertness to acidic slurries. The composite structure maintains bonding strength while eliminating the chemical reactivity issues that compromise reliability in acidic environments.
Solution Approach 2:
The patent creates a chemically inert environment by using alumina or silica ceramic matrices that are resistant to chemical reactions with acidic CMP slurries. This inert matrix environment protects the abrasive particles from chemical degradation and prevents metal ion contamination, thereby maintaining bond stability and reliability throughout the conditioner's service life.
3Measurement precision
If small diamond particles less than 45 μm are used, then finer polishing capability is achieved, but traditional bonding methods cannot embed them without burying them in the matrix
Solution Approach 1:
The patent uses a ceramic composite matrix system (alumina-silica or alumina-alumina) with optimized porosity and mechanical properties that enables effective embedding of fine cBN particles (10-50 μm). The composite structure provides appropriate hardness and bonding characteristics that prevent burying of small particles while maintaining polishing fineness, thus resolving the manufacturing difficulty associated with small abrasive particles.
4Reliability
If proprietary sorting and orienting processes are used to control diamond distribution, then better performance consistency is achieved, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent fundamentally changes the approach to achieving performance consistency by using synthetic cBN particles with inherently uniform parameters (size, shape, composition) from the manufacturing process itself. This eliminates the need for complex post-manufacturing sorting and orienting processes, as the particles are produced with consistent properties directly, thereby reducing device complexity while maintaining 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 solution provides consistent and reproducible performance, reduces scratching and metal ion contamination, and extends the life of the polishing pad, while maintaining low defect rates and wear rates.
Implementation Method 1
at least the first major surfaces of the first and second abrasive elements comprise a plurality of precisely shaped features, that are projections in the abrasive elements that are for protruding toward a workpiece and polishing said workpiece
Implementation Method 2
providing a resilient element having first and second major surfaces, affixing the first major surface of the resilient element to the second major surfaces of the abrasive elements
Data Source
Figure 1a~1b
Figure 2~3b
Figure 4a~4b
AI summary
An abrasive article includes a first abrasive element, a second abrasive element, a resilient element having first and second major surfaces, and a carrier. The first element and the second abrasive element each comprises a first major surface and a second major surface. At least the first major surfaces of the first and second abrasive elements comprise a plurality of precisely shaped features. The abrasive elements comprise substantially inorganic, monolithic structures.