Wafer Handling End Effector

Wafer Handling End Effector is a type of robot hand designed specifically for the semiconductor industry, usually used to handle and transfer wafers. The production environment of wafers requires extremely high cleanliness, because tiny particles or contaminants can cause chips to fail during processing. 

Ceramic materials are widely used in the manufacture of these hands due to their excellent physical and chemical properties.

Purity and composition

The purity of alumina is usually ≥99.9%, and the metal impurities (such as MgO, CaO, SiO₂) are controlled within 0.05% to 0.8% to improve the resistance to plasma etching.

α-phase alumina (corundum structure) is the main, the crystal type is stable, the density is 3.98 g/cm³, and the actual density after sintering is 3.6~3.9 g/cm³.

Mechanical property

Hardness: Mohs hardness 9~9.5, Vickers hardness 1800~2100 HV, higher than stainless steel and alloy.

Bending strength: 300~400 MPa, which can withstand the mechanical stress of high speed handling of wafer.

Elastic modulus: 380~400 GPa, to ensure that the handling arm is rigid and not easy to deform.

Thermal and electrical properties

Thermal conductivity: 20~30 W/(m·K), still maintain stable insulation (resistivity >10¹⁴ Ω·cm).

Temperature resistance: long-term use temperature can reach 850~1300℃, suitable for vacuum high temperature environment.

Surface characteristic

Surface roughness: Ra≤ 0.2μm (after polishing) to avoid wafer scratches

Vacuum adsorption porosity: Hollow structure achieved by isostatic pressing, porosity <0.5%.

Second, structural design features

Lightweight and strength optimization

Using an integrated molding process, the weight is only 1/3 of the metal arm, reducing the positioning error caused by inertia.

The end-effector is designed as a gripper or vacuum absorber, and the contact surface is coated with an antistatic coating to prevent the wafer from contaminating the 710 by electrostatic adsorption.

Pollution resistance

High purity alumina is chemically inert, does not release metal ions, and meets the SEMI F47 cleanliness standard (particle pollution <10 ppm).

Third, manufacturing process requirements

Forming and sintering

Isostatic pressing (pressure 200~300 MPa) to ensure the material density >99.5%.

High temperature sintering (1600~1800℃), grain size control in 1~ 5μm to balance strength and toughness.

Precision machining

Diamond grinding processing, dimensional accuracy ± 0.01mm, flatness ≤ 0.05mm/m

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