Metal-Backed Porous SiC Vacuum Chuck for Warped & Thin Wafer Handling

St.Cera’s metal based ceramic vacuum chuck combines a porous silicon carbide (SiC) ceramic layer with a precision-machined metal base (aluminum or stainless steel). The porous SiC material (blue-black, porosity 35–40%, pore size 20–30 μm, permeability 60 ml/cm²·min) provides uniform, gentle vacuum distribution across the entire wafer surface, eliminating edge marking and enabling non-contact support for thin (≤100 μm) or warped wafers. The SiC layer offers low thermal expansion (3.5×10⁻⁶/℃), thermal stability up to 1000°C, and moderate flexural strength (32–35 MPa). The metal base adds structural rigidity, easy mounting via threaded holes, and protection against brittle fracture. This chuck is ideal for backside grinding, dicing, and high-temperature wafer processing where uniform vacuum and thermal compatibility are critical.

Specifications (based on supplied porous SiC data):

Note: Flexural strength is lower than dense SiC due to porosity. Metal base properties are not from ceramic tables.

Applications:

• · Backside grinding of thin wafers (≤100 μm)
• · Warped wafer mounting for dicing
• · High-temperature wafer chucking (up to 1000°C)
• · Vacuum fixturing for porous or fragile substrates

Manufacturing:

Porous SiC plate (formed with pore formers, sintered) → lapped to flatness ≤10 μm → metal base machined with vacuum ports and mounting features → epoxy bonding or mechanical clamping → helium leak test.

Quality Control:

• · Porosity and pore size verified by SEM
• · Permeability test (air flow)
• · Flatness measured with laser interferometer
• · Helium leak rate <1×10⁻⁹ Pa·m³/s

Advantages over Grooved or Dense Ceramic Chucks:

• · No wafer marking – uniform vacuum without discrete holes
• · Self-cleaning pores – reduced clogging
• · Handles warped wafers (up to 500 μm bow)
• · Metal base prevents brittle fracture and simplifies integration

Limitations:

• · Lower flexural strength (32–35 MPa) – avoid impact loading
• · Operating temperature limited to 1000°C (porous SiC), but metal base epoxy bond limits to ≤200°C unless mechanically clamped
• · Not for high-pressure vacuum (porous structure limits max vacuum differential)

Customization:

• · Metal base: aluminum (light), stainless steel (corrosion resistant), Invar (low expansion)
• · Bonding: epoxy (≤200°C) or mechanical clamp (up to 500°C)
• · Edge sealing ring for zone vacuum control

Please note: The supplied flexural strength (32–35 MPa) is significantly lower than dense ceramics due to porosity. Handle with care to avoid edge chipping.