CLASS 4 Material Preparation Guide

Class 4: Soft, Brittle Non-metals

Class 4 materials include brittle ceramics and electronic components such as multilayer capacitors and MEMS devices. These materials are highly sensitive to mechanical stress during preparation and require careful handling to preserve delicate internal structures and prevent surface damage.

Hardness Range
High; brittle with low fracture toughness
Typical Materials
Silicon, GaAs, Ferrites, PZTs, MLC Capacitors, MEMS
Preparation Challenge
Relief Control & Void Preservation

Material Categories

MLC Capacitors

Key Materials
  • BaTiO₃ Ceramic
  • Nickel or Silver Layers
  • Glass or polymer end caps
Key Features
  • Alternating ceramic and metal layers
  • Micron-scale structure
  • Highly sensitive to prep damage

Semiconductors

Common Types
  • Silicon (Si)
  • Gallium Arsenide (GaAs)
  • Silicon Carbide (SiC)
Key Features
  • Hard but brittle
  • Thin-film layers and junctions
  • Highly polished surfaces required

Functional Ceramics

Examples
  • Ferrites
  • PZTs (Lead Zirconate Titanate)
  • Dielectric Ceramics
Considerations
  • Highly porous or layered structures
  • Prone to chipping and delamination
  • Require gentle, low-relief prep methods

Preparation Guide

Key Preparation Challenges

Layer Delamination

Metal and ceramic layers in MLCs may separate if excessive force is applied during grinding or polishing.

Void Collapse

Porous ceramics may fracture or crush under grinding unless properly supported with resin.

Polishing Relief

Hard/soft layering causes uneven material removal, obscuring fine internal features.

Coating Damage

Thin coatings or films can be easily removed or distorted without controlled prep conditions.

Recommended Preparation Steps

Sectioning

Use low-force wafering saws with diamond blades and adequate cooling to prevent edge chipping.

Mounting

Vacuum impregnation is essential to fill internal voids and stabilize fragile features prior to grinding.

Grinding

Use very fine diamond or alumina abrasives with low pressure. Avoid coarse SiC papers to reduce risk of delamination.

Polishing

Polish using low-napped cloths with diamond followed by colloidal silica. Minimize relief and preserve interfaces.

Quality Verification

Confirm ceramic-metal layers remain flat and intact

Check for absence of polishing relief at layer boundaries

Ensure voids are clean and fully visible

Verify coatings and films are undisturbed