초록 ▼

AC waveforms biasing of bead transporter chucks and their accumulated charge sensing circuits tailored for low resistivity substrates and beads where if traditional DC quasi-static biasing potentials were used, the bead attraction potentials of the chuck would undergo rapid RC decay and cause the be

AC waveforms biasing of bead transporter chucks and their accumulated charge sensing circuits tailored for low resistivity substrates and beads where if traditional DC quasi-static biasing potentials were used, the bead attraction potentials of the chuck would undergo rapid RC decay and cause the bead transporter chuck to stop working. Methods for selecting AC waveforms are given, including those that maximize the time average of the bead attraction potential at the bead collection zone of the bead contact surface.

대표청구항 ▼

[ What is claimed is:] [3.] A method for adhering charged grains to a bead collection zone on a bead contact surface comprising:(1) adhering a substrate with a resistivity below 10.sup.11 .OMEGA.-cm to an electrostatic chuck, with the substrate arrayed over a grain-attracting electrode of the electr

[ What is claimed is:] [3.] A method for adhering charged grains to a bead collection zone on a bead contact surface comprising:(1) adhering a substrate with a resistivity below 10.sup.11 .OMEGA.-cm to an electrostatic chuck, with the substrate arrayed over a grain-attracting electrode of the electrostatic chuck so that a surface of the substrate defines the bead contact surface;(2) applying an AC waveform potential to the grain-attracting electrode to create a grain attracting field, wherein the AC waveform potential comprises a grain-attracting potential pulse followed by a recovery period adapted to allow an effective grain attraction potential at the bead collection zone on activation of a subsequent grain-attracting potential pulse,wherein the AC waveform potential has a frequency of 100 Hz or less, orthe AC waveform potential corresponds to applied voltages and time periods effective so that the voltage at the bead collection zone resulting from the grain-attracting potentials following a grain-attracting potential is at least 10% of an initial voltage at the bead collection zone, orthe AC waveform potential corresponds to applied voltages and time periods effective so that the integrated voltage at the bead collection zone integrated over the pulse period during which a grain-attracting voltage is applied voltage at the bead collection zone is at least 20% of an initial integrated voltage; and(3) attracting and retaining a grain to the bead collection zone.