Lead-Free Glass Passivation for Electronic Components
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Solution Overview
Problem
Existing passivation glasses for electronic components contain high percentages of lead oxide, which is environmentally harmful and difficult to replace with other ingredients to achieve desired technical properties, and tend to devitrify, affecting component functionality.
Innovation Solution
A lead-free glass composition is developed with specific weight percentages of SiO2, B2O3, Al2O3, Cs2O, MgO, BaO, Bi2O3, CeO2, MoO3, Sb2O3, and ZnO, applied as a suspension and sintered onto electronic components to provide a stable, non-devitrifying passivation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead oxide is used in passivation glass to achieve desired technical properties (electrical insulation, mechanical stability), then the glass provides good passivation performance, but the glass becomes environmentally harmful and difficult to dispose of
Solution Approach 1:
The patent replaces lead oxide with zinc oxide as the primary modifying component, fundamentally changing the chemical composition parameters. This substitution maintains the glass's technical properties (electrical insulation, mechanical stability, thermal expansion match) while eliminating the environmentally harmful lead oxide, thus resolving the contradiction between performance and environmental harm
Solution Approach 2:
The patent creates a composite glass system combining multiple oxides (SiO2, B2O3, Al2O3, ZnO, MgO, BaO, Bi2O3, CeO2, MoO3, Sb2O3) to achieve the desired passivation properties without lead oxide. This composite approach allows the glass to maintain high electrical insulation and mechanical stability while being environmentally friendly
2Reliability
If standard passivation glasses are used to provide mechanical protection and electrical insulation, then component reliability is improved, but the glass tends to devitrify during subsequent processing steps
Solution Approach 1:
The patent modifies the glass composition by incorporating specific amounts of CeO2 (0.01-1%, preferably 0.1-0.5%) and controlling the ZnO content (50-65%, preferably 55-62.5%), which suppresses devitrification during sintering and subsequent processing. This compositional adjustment maintains glass stability while providing the required mechanical protection and electrical insulation
Solution Approach 2:
The patent introduces small amounts of CeO2 and other metal oxides (MoO3, Sb2O3) as intermediaries that prevent crystallization and devitrification of the glass matrix during thermal processing. These intermediary components stabilize the glass structure during sintering and subsequent processing steps, preventing degradation of the passivation layer
3Object-affected harmful factors
If glass composition is modified to replace lead oxide, then environmental compliance is improved, but achieving desired technical properties becomes difficult
Solution Approach 1:
The patent employs a multi-component composite glass system where each oxide serves a specific function: SiO2 and B2O3 form the glass network, Al2O3 provides structural stability, ZnO acts as the primary modifier replacing lead oxide, MgO and BaO adjust thermal and electrical properties, and trace amounts of CeO2, MoO3, and Sb2O3 control devitrification and processing behavior. This sophisticated composite formulation achieves both environmental compliance and precise control of technical properties
Solution Approach 2:
The patent precisely controls the composition parameters within specific ranges (e.g., ZnO: 50-65%, B2O3: 15-25%, SiO2: 3-12%) to optimize the balance between environmental compliance and technical performance. By carefully adjusting these parameters, the glass achieves the required electrical insulation, mechanical stability, and thermal expansion characteristics without lead oxide
4Strength
If glass passivation is applied to protect electronic components, then mechanical protection is improved, but chemical resistance to subsequent processing steps varies and may be attacked
Solution Approach 1:
The patent optimizes the glass composition by adjusting the ratio of network formers (SiO2, B2O3) to modifiers (ZnO, MgO, BaO) to enhance chemical resistance. The high ZnO content (50-65%) combined with specific amounts of Al2O3 and B2O3 creates a chemically stable glass structure that resists attack from etching solutions and processing chemicals, while maintaining mechanical protection
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
The lead-free glass composition achieves desired technical properties for electronic component passivation, including mechanical protection, acid resistance, and electrical insulation without using lead oxide, and is resistant to subsequent processing steps, ensuring component stability and compliance with environmental regulations.
Implementation Method 1
sintering the component
Data Source
AI summary
The method for producing glass-coated electronic components includes processing a lead-free glass with a liquid to form a suspension, applying the suspension on an electronic component body and subsequently sintering the component body with the suspension on it. The lead-free glass contains, in % by weight, SiO2, 3-12; B2O3, 15-<25; Al2O3, 0-6; Cs2O, 0-5; MgO, 0-5; BaO, 0-5; Bi2O3, 0-5; CeO2, 0.01-1; MoO3, 0-1; Sb2O3, 0-2 and ZnO, 50-65. The method can be used to passivate electronic components.