Semiconductive Ceramic Sintered Compact for Static Electricity Removal
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Solution Overview
Problem
Existing semiconductive ceramics used in semiconductor and liquid crystal manufacturing apparatuses face challenges in achieving high conductivity for static electricity removal while maintaining excellent mechanical properties and stability over time, particularly due to electrostatic discharge issues during microminiaturization and increased device size.
Innovation Solution
A semiconductive ceramic sintered compact is developed with a structure comprising a main phase of Al2O3 particles and grain boundary phases containing conductive substances, where Al2O3 particles are present in an island-sea form within a conductive phase, and a second phase with the same composition electrically connects the first phases three-dimensionally, incorporating Fe, Ti, and Mn to enhance conductivity and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive substances are added to alumina to lower surface and volume resistivity for static electricity removal, then conductivity is improved, but mechanical properties deteriorate
Solution Approach 1:
The invention divides the grain boundary phase into two distinct phases: a first grain boundary phase containing conductive substances (Fe, Ti, Mn oxides) dispersed in a glassy matrix, and a second grain boundary phase consisting of crystalline alumina. This segmentation allows the conductive first phase to provide static electricity removal functionality while the crystalline alumina second phase maintains mechanical strength, resolving the contradiction between conductivity and mechanical properties.
2Reliability
If special sintering methods are used to achieve antistatic properties, then conductivity is improved, but manufacturing complexity increases
Solution Approach 1:
The invention achieves antistatic properties by controlling compositional parameters rather than using special sintering methods. Specifically, it formulates the first grain boundary phase with conductive substances (Fe2O3: 0.1-5 wt%, TiO2: 0.1-5 wt%, MnO2: 0.1-5 wt%) and controls the glassy phase composition (SiO2: 70-90 wt%, Al2O3: 5-30 wt%). This compositional parameter control enables antistatic functionality through conventional sintering processes, avoiding the need for complex special sintering methods.
3Reliability
If three-dimensional electrical connection of grain boundary phases is achieved, then conductivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The invention achieves three-dimensional electrical connection by extending the first grain boundary phase (containing conductive substances) continuously along the sintered compact in three dimensions. This is accomplished through proper formulation of the glassy phase composition and sintering conditions that promote continuous grain boundary phase formation. The continuous three-dimensional network of the first grain boundary phase provides reliable electrical connectivity without requiring extremely precise microstructure control, as the glassy matrix naturally forms continuous pathways during sintering.
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 sintered compact achieves high conductivity for static electricity removal and antistatic purposes while maintaining excellent mechanical stability and accuracy over time, effectively suppressing electrostatic discharge and supporting microminiaturization and increased device size without compromising planar parallelism.
Implementation Method 1
the first phase is a grain boundary phase comprising a conductive substance-containing conductive phase and Al2O3 particles... the second phase is a grain boundary phase containing a conductive phase having the same composition as the conductive phase in the first phase and having a structure that electrically connects the first phases three-dimensionally to each other
Implementation Method 2
the sintered compact can be densified by sintering at ordinary atmospheric pressure
Data Source
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AI summary
There is provided a semiconductive ceramic sintered compact that has a conductivity high enough to attain static electricity removal and antistatic purposes and, at the same time, has excellent mechanical properties or stability over time. The semiconductive ceramic sintered compact includes at least a main phase and first and second phases contained in the main phase observed as a result of observation of any face of the sintered compact, the main phase being a ceramic sintered phase containing Al2O3 particles, the first phase being a grain boundary phase including a conductive substance-containing conductive phase and Al2O3 particles, the Al2O3 particles being present in an island-sea form in the conductive phase, the second phase being a grain boundary phase containing a conductive phase having the same composition as the conductive phase in the first phase and having a structure that electrically connects the first phases three-dimensionally to each other.