Stepped indirectly heated cathode with improved shielding

Patent metadata

Field	Value
Publication number	US-11244800-B2
Application number	US-202117330801-A
Country	US
Kind code	B2
Filing date	May 26, 2021
Priority date	Jun 18, 2020
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

An ion source for forming a plasma has a cathode with a cavity and a cathode surface defining a cathode step. A filament is disposed within the cavity, and a cathode shield has a cathode shield surface at least partially encircling the cathode surface. A cathode gap is defined between the cathode surface and the cathode shield surface, where the cathode gap defines a tortured path for limiting travel of the plasma through the gap. The cathode surface can have a stepped cylindrical surface defined by a first cathode diameter and a second cathode diameter, where the first cathode diameter and second cathode diameter differ from one another to define the cathode step. The stepped cylindrical surface can be an exterior surface or an interior surface. The first and second cathode diameters can be concentric or axially offset.

First claim

The invention claimed is:

1. An ion source for forming a plasma, the ion source comprising:
a cathode comprising:
a cathode surface defining a cathode step; and
a cavity;

a filament disposed within the cavity; and
a cathode shield having a cathode shield surface at least partially encircling the cathode surface, wherein a cathode gap is defined between the cathode surface and the cathode shield surface.

2. The ion source of claim 1 , wherein the cat…

Assignees

• Axcelis Tech Inc

Inventors

• Platow Wilhelm
• Bassom Neil
• Satoh Shu
• Silverstein Paul
• Farley Marvin

Classifications

• H01J1/52

  Electricity · mapped topic

• H01J1/20

  Electricity · mapped topic

• H01J1/025 Primary

  Electricity · mapped topic

• H01J2201/19

  Electricity · mapped topic

• H01J2203/04

  Electricity · mapped topic