Glass Composition Balancing Deflection, Meltability, and Transmittance
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Solution Overview
Problem
Manufacturing glass with low thermal expansion and high Young's modulus for semiconductor device support is challenging, and existing glasses often suffer from poor transmittance and manufacturing difficulties.
Innovation Solution
A glass composition comprising SiO2 (40-60%), B2O3 (0.01-15%), Al2O3+rare earth oxide (0-20%), with specific ratios to balance thermal expansion, Young's modulus, and meltability, ensuring easy manufacturing and high transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass composition is optimized for low thermal expansion and high Young's modulus, then deflection is suppressed, but manufacturing becomes difficult and transmittance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition ratios of oxides in the glass. Specifically, it sets Al2O3 content at 15-30%, B2O3 at 3-10%, and SiO2 at 60-75%, while controlling the ratio (Al2O3+B2O3)/SiO2 at 0.10-0.30. These parameter optimizations enable the glass to achieve both low thermal expansion (α ≤ 5.0 ppm/°C) and high Young's modulus (E ≥ 85 GPa) while maintaining manufacturability and transmittance.
2Strength
If glass composition is optimized for low thermal expansion and high Young's modulus, then deflection is suppressed, but transmittance deteriorates
Solution Approach 1:
The patent resolves the transmittance issue through parameter optimization by controlling the base glass composition. It specifies SiO2 at 60-75% and B2O3 at 3-10%, which provides good optical properties. Additionally, it strictly limits impurity content (Fe2O3 ≤ 0.1%, TiO2 ≤ 0.05%, Nb2O5 ≤ 0.05%) to maintain high transmittance while achieving the required mechanical strength and low thermal expansion.
3Strength
If Al2O3 content is increased to suppress deflection, then Young's modulus increases, but meltability deteriorates
Solution Approach 1:
The patent uses B2O3 as an intermediary substance to improve meltability while Al2O3 provides high Young's modulus. By setting B2O3 at 3-10% and controlling the ratio (Al2O3+B2O3)/SiO2 at 0.10-0.30, the B2O3 acts as a flux that lowers the melting temperature and improves meltability, enabling the Al2O3-containing glass to be manufactured easily while maintaining high mechanical strength.
Data Source
AI summary
Manufacturing is facilitated while deflection is suppressed, and transmission ability is increased. A glass (10) contains SiO2: 40% to 60%, B2O3: 0.01% to 15%, and Al2O3+rare earth oxide: 0% to 20% as expressed in mol % on an oxide basis, and the ratio of the total content of Al2O3 and ΣRO to the total content of SiO2, Al2O3, and ΣRO (that is, (Al2O3+ΣRO)/(SiO2+Al2O3+ΣRO)) is 0.38 or more.