Adhesion Control through Electric Field-Induced Water Adsorption at Oxidized Silicon Interfaces

TL;DR

This study uncovers how electric field-induced water adsorption at oxidized silicon interfaces influences adhesion hysteresis, offering new methods for adhesion control in chip manufacturing processes.

Contribution

It demonstrates that water adsorption, rather than charge trapping or siloxane bonds, governs adhesion hysteresis under electric fields at silicon interfaces.

Findings

Adhesion can be tuned via electric field-induced water adsorption.

Charge trapping and siloxane bonds are not primary factors in adhesion hysteresis.

Water adsorption effects are significant at low relative humidity (<10%).

Abstract

Adhesion plays a pivotal role in computer chip manufacturing, directly affecting the precision and durability of positioning components such as wafer stages. Electrical biasing is widely employed to eliminate floating potential and to enable electrostatic clamping. However, upon electrical grounding adhesion can persist and there is limited knowledge about the nature of this adhesion hysteresis. Here, we investigate potential causes underlying electric field-induced adhesion hysteresis at the interface between an n-type AFM tip and a p-type silicon sample using atomic force microscopy. Our findings reveal that neither charge trapping nor siloxane bond formation significantly impacts the measured adhesion. Surprisingly, we show that adhesion can be tuned through electric field-induced water adsorption under low relative humidity (RH < 10%). Our results provide new insights into adhesion hysteresis and opportunities for adhesion control.