US 5,347,138 A · In situ real time particle monitor for a sputter coater chamber

Abstract

A structure and a method use a non-invasive particle monitor to detect particles in a process chamber for a "down sputtering" metal deposition process. In one embodiment, only non-spherical particles are detected using a single laser beam of a predetermined polarization is used, and the phase shift in the polarization due to the passing of a particle through the laser beam is measured. In another embodiment, two closely spaced orthogonally polarized laser beams are used, and the differential intensity of the laser beams is measured when a particle passes through one of the laser beams. In another embodiment, shield tubes for housing optical components are used to prevent coating of the optical components and to prevent deposition to take place outside the shielded area. Internal electric and magnetic fields are used to drive particles through the laser beams for particle detection.

Claims18

Dependent claims

An apparatus for monitoring particles in a process chamber for a sputter deposition process using plasma, said process chamber having first and second ports allowing access to said plasma in said process chamber, comprising:

a laser source for providing an incident laser beam;
a set of optical components for collimating, polarizing and focussing said laser beam through said first and second ports on said plasma;
and
a detector for detecting from a measurement of the phase of said incident laser beam particles in said plasma passing through said incident laser beam.

1 more element

A method for detecting particles in a process chamber for a sputter deposition process using plasma, said process chamber having first and second ports allowing access to said plasma in said process chamber, comprising the steps of:

providing an incident laser beam;
providing a set of optical components for collimating, polarizing and focussing said incident laser beam, so as to allow said incident laser beam to enter said process chamber through said first port, passing through said plasma and exiting said process chamber through said second port;
and
providing a detector for detecting from said laser beam whether or not particles in said plasma pass through said laser beam.

1 more element

Dependencies are inferred from the claim text.

In situ real time particle monitor for a sputter coater chamber

Life of this patent

In situ real time particle monitor for a sputter coater chamber

Life of this patent

Abstract

Claims18