1. Significance of Ceramic Substrates Research

Ceramic substrates, known for their exceptional physical and chemical properties, are increasingly critical in high-tech applications. Their characteristics include:

• High thermal conductivity
• Low dielectric constant and dielectric loss
• Excellent electrical insulation
• Thermal expansion coefficient compatible with silicon materials

These properties make ceramic substrates ideal for high-density, high-power, and high-speed integrated circuits. They enhance performance, improve reliability, and foster innovation in the following fields:

• Electronics: Used as bases and packaging materials for electronic components. High thermal conductivity aids heat dissipation, while low dielectric constants improve signal transmission and reduce energy loss.
• Aerospace and Military: Their stability under high temperature, pressure, and corrosive conditions makes ceramic substrates indispensable.

Research on ceramic substrates focuses on their manufacturing processes, performance optimization, and application expansion to meet growing industrial demands. Among the preparation methods, tape casting and dry pressing stand out due to their distinct advantages and disadvantages.

2. Tape Casting Method

2.1 Advantages of the Tape Casting Process

1. Uniformity and Precision

   • Produces thin, large-area ceramic substrates with consistent thickness and smooth surfaces.
   • Particularly suited for high-precision electronics and IC packaging.

2. High Production Efficiency

   • Enables continuous, automated production with lower labor costs.

3. Efficient Material Utilization

   • Minimizes material waste by evenly spreading slurry on the substrate.

4. Customizable Performance

   • Through optimized formulations and parameters, substrates with specific properties, such as high thermal conductivity or low dielectric loss, can be produced.

2.2 Disadvantages of the Tape Casting Process

1. Brittleness

   • High strength but prone to cracking under impact or bending.

2. Parameter Sensitivity

   • Requires precise control of blade gap, slurry viscosity, drying, and sintering. Minor errors can lead to defects (e.g., cracks, deformation, or pores).

3. Environmental Concerns

   • High usage of organic solvents and binders leads to emissions during processing, necessitating additional treatment.

4. High Production Costs

   • Equipment and material requirements are significant, and production inefficiencies (e.g., waste) can increase costs.

5. Shape Limitations

   • Effective for thin, flat ceramics but less so for complex or thick designs.

3. Dry Pressing Method

3.1 Advantages of the Dry Pressing Process

1. High Green Body Density

   • The pressure applied ensures a compacted structure, aiding sintering and enhancing mechanical strength.

2. Simplicity

   • Straightforward operation with minimal skill requirements, ideal for large-scale production.

3. Lower Costs

   • Limited use of organic binders and a simple process reduce costs.

4. Stable Product Performance

   • Results in uniform microstructures and consistent properties.

3.2 Disadvantages of the Dry Pressing Process

1. Pressure-Related Issues

   • High-pressure requirements cause mold and equipment wear, increasing maintenance costs.
   • Internal stresses can degrade performance.

2. Size Limitations

   • Limited by mold size and press capacity, making it unsuitable for large ceramic substrates.

3. Non-Uniform Pressure Distribution

   • Unidirectional pressing causes uneven pressure, leading to cracks, delamination, and non-uniform density.

4. Lower Efficiency

   • Batch processing and repeated operations (feeding, pressing, demolding) reduce productivity.

5. Shape Constraints

   • Best suited for simple geometries; complex or large designs require costly molds.

6. Defects and Mold Wear

   • Powder inconsistencies and stress during pressing can cause cracks, pores, and delamination.
   • Long-term mold use leads to wear, affecting precision and quality, increasing costs.