Silicate-Embedded Hollow Microspheres for Low-Scratch CMP Pads
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Solution Overview
Problem
Chemical mechanical polishing (CMP) operations face issues such as wafer scratching due to foreign materials in polishing pads, leading to defects and variability in pad performance, which affects the planarization and removal rate of semiconductor substrates.
Innovation Solution
A composite polishing pad with gas-filled polymeric microelements embedded with silicate particles, where the silicate particles are distributed to minimize scratching and gouging, and air classification is used to control the morphology and distribution of these particles, ensuring consistent pad properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hard glass spheres are used in the polishing pad, then scratching resistance is improved, but polishing rate decreases
Solution Approach 1:
The polishing pad uses a composite structure combining a polymeric matrix with hollow polymeric microelements containing silicate particles. This composite design allows the pad to achieve both low scratching (through the compliant polymeric shell) and high polishing rate (through the silicate particles), resolving the contradiction between scratching resistance and polishing rate.
Solution Approach 2:
The invention changes the material parameters from hard glass spheres to hollow polymeric microelements with specific density ranges (5-200 g/liter) and shell thicknesses. These parameter changes allow the pad to maintain structural integrity while providing compliant contact that reduces scratching, simultaneously achieving both low scratching and high polishing rate.
2Productivity
If silicate particles are added to enhance removal rate, then polishing productivity is improved, but wafer scratching increases
Solution Approach 1:
The silicate particles are distributed within the hollow polymeric microelements rather than being uniformly dispersed throughout the pad. This localized distribution ensures that silicate particles are present at the polishing interface to enhance removal rate, while the polymeric matrix provides overall compliance to minimize scratching, resolving the contradiction between productivity and harmful factors.
Solution Approach 2:
The hollow polymeric microelements act as intermediaries that carry silicate particles to the polishing interface. The polymeric shell protects the silicate particles from directly causing scratches, while still allowing them to contribute to material removal, thus resolving the contradiction between enhanced removal rate and reduced scratching.
3Manufacturing precision
If traditional casting techniques with controlled curing cycles are used, then macro-properties of the pad are improved, but micro-polishing aspects and pad-to-pad variability are not addressed
Solution Approach 1:
The invention segments the polishing pad into discrete hollow polymeric microelements with consistent morphology. By controlling the morphology of individual microelements through the manufacturing process, the invention achieves both good macro-properties and reduced pad-to-pad variability, as each microelement contributes consistently to the overall pad performance.
Solution Approach 2:
The invention introduces specific parameter controls for the hollow polymeric microelements including density (5-200 g/liter), shell thickness, and particle size distribution. These parameter specifications ensure consistent micro-polishing characteristics across different pads, reducing pad-to-pad variability while maintaining good macro-properties.
Data Source
AI summary
The invention provides a plurality of polymeric particles embedded with silicate that include gas-filled polymeric microelements. The gas-filled polymeric microelements have a shell and a density of 5 g/liter to 200 g/liter. The shell having an outer surface and a diameter of 5 μm to 200 μm with silicate particles embedded in the polymer. The silicate particles have an average particle size of 0.01 to 3 μm. The silicate-containing regions are spaced to coat less than 50 percent of the outer surface of the polymeric microelements; and less than 0.1 weight percent total of the polymeric microelements is associated with i) silicate particles having a particle size of greater than 5 μm; ii) silicate-containing regions covering greater than 50 percent of the outer surface of the polymeric microelements; and iii) polymeric micro elements agglomerated with silicate particles to an average cluster size of greater than 120 μm.