Electric field sensor, surface wave plasma source, and surface wave plasma processing apparatus

Patent metadata

Field	Value
Publication number	US-11244810-B2
Application number	US-202016872778-A
Country	US
Kind code	B2
Filing date	May 12, 2020
Priority date	May 13, 2019
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

An electric field sensor includes a probe, a cylindrical probe guide, an insulating member, a preload spring and a connector. The probe serves as an inner conductor of a coaxial transmission path and has a portion forming a monopole antenna at a tip end to be in constant contact with a microwave transmission window by a pressing force of a built-in spring thereof. The probe guide is disposed at an outer side of the probe and serves as an outer conductor of the coaxial transmission path. The insulating member is disposed between the probe and the probe guide. The preload spring preloads the probe guide downward and presses the probe guide so that the tip end of the probe guide comes in constant contact with the planar slot antenna. The connector is connected to the probe and the probe guide to connect coaxial signal cables for extracting signals.

First claim

What is claimed is:

1. An electric field sensor for detecting an electric field of microwaves in generating surface wave plasma by emitting microwaves transmitted through a microwave transmission path into a chamber through slots of a planar slot antenna and a microwave transmission window made of a dielectric material, the electric field sensor comprising:
a probe serving as an inner conductor of a coaxial transmission path and having a built-in spring and a portion forming a monopole antenna at a tip end thereof so that the tip end of the probe is in constant contact with a rear surface of the microwave transmission window by a pressing force of the built-in spring;
a cylindrical probe guide disposed at an outer side of the probe, serving as an outer conductor of the coaxial transmission path, and having a tip end to be in contact with a rear surface of the planar slot antenna;
an insulating member disposed between the probe and the probe guide;
a preload spring configured to preload the probe guide downward and press the probe guide so that the tip end of the probe guide comes in constant contact with the planar slot antenna; and
a connector connected to the probe and the probe guide and configured to connect coaxial signal cables for extracting signals.

2. The electric field sensor of claim 1 , wherein a length of the portion of the probe that forms the monopole antenna is within a range from 1.5 to 2 mm.

3. The electric field sensor of claim 1 , wherein the tip end of the probe has a fillet shape.

4. The electric field sensor of claim 1 , wherein the tip end of the probe guide has a fillet shape.

5. The electric field sensor of claim 1 , further comprising:
a fixing nut into which the probe guide is inserted, and configured to fix the probe guide to a fixing portion,
wherein when the fixing nut is tightened to the fixing portion, the preload spring is compressed and the probe guide is preloaded downward.

6. The electric field sensor of claim 5 , further comprising:
a rotation stopper installed at the fixing nut and configured to restrict a rotation of the probe guide while allowing a vertical movement of the probe guide.

7. The electric field sensor of claim 6 , wherein the rotation stopper is a set screw that is screw-coupled to a screw hole formed through a side surface of the fixing nut, and a tip end of the rotation stopper is inserted into a recess formed in a side surface of the probe guide to be vertically movable.

8. The electric field sensor of claim 1 , further comprising:
a band-type contact connected to a ground potential and having a cylindrical main body made of a conductive material and a contact member disposed at an inner side of the main body to be in contact with the main body,
wherein the contact member is formed by arranging a plurality of plate springs, each being made of a conductive material, along a circumferential direction while central portions of the plate springs protrude inward, and
when the probe guide is inserted into the contact member, electrical connection between the probe guide and the contact member is ensured.

9. The electric field sensor of claim 7 , further comprising:
a band-type contact connected to a ground potential and having a cylindrical main body made of a conductive material and a contact member disposed at an inner side of the main body to be in contact with the main body,
wherein the contact member is formed by arranging a plurality of plate springs, each being made of a conductive material, along a circumferential direction while central portions of the plate springs protrude inward, and
when the probe guide is inserted into the contact member, electrical connection between the probe guide and the contact member is ensured.

10. A surface wave plasma source for generating surface wave plasma in a chamber by supplying microwaves into the chamber, comprising:
a microwave output unit configured to output microwaves;
at least one microwave emission mechanism disposed on a microwave transmission path for transmitting the microwaves outputted from the microwave output unit and configured to emit the microwaves into the chamber; and
the electric field sensor described in claim 1 configured to detect an electric field of the microwaves emitted from the at least one microwave emission mechanism,
wherein the at least one microwave emission mechanism includes:
a planar slot antenna configured to emit the microwaves transmitted through the microwave transmission path into the chamber from slots of the planar slot antenna;
a wave retardation member made of a dielectric material and disposed on an upstream side in a microwave transmission direction of the planar slot antenna,
a microwave transmission window made of a dielectric material and disposed on a downstream side in the microwave transmission direction of the planar slot antenna, and
at least one sensor insertion hole formed through the wave retardation member and the planar slot antenna wherein the electric field sensor is inserted into the at least one sensor insertion hole.

11. The surface wave plasma source of claim 10 , wherein the at least one sensor insertion hole includes two or more sensor insertion holes arranged at regular intervals on the same circumference around an axis of the microwave transmission path in a region at the inner side of the slots of the planar slot antenna,
the number of the two or more sensor insertion holes is n times the number of the slots where n is an integer of 1 or more, and
the electric field sensor is inserted into at least one of the two or more sensor insertion holes.

12. The surface wave plasma source of claim 10 , wherein the at least one microwave emission mechanism includes two or more microwave emission mechanisms, and the microwaves emitted from the two or more microwave emission mechanisms into the chamber are combined in a space in the chamber to thereby generate the surface wave plasma.

13. The surface wave plasma source of claim 11 , wherein the at least one microwave emission mechanism includes two or more microwave emission mechanisms, and the microwaves emitted from the two or more microwave emission mechanisms into the chamber are combined in a space in the chamber to thereby generate the surface wave plasma.

14. A surface wave plasma processing apparatus for processing a substrate with surface wave plasma, comprising:
a chamber accommodating the substrate;
a gas supply mechanism configured to supply a gas into the chamber; and
the surface wave plasma source of claim 10 configured to generate the surface wave plasma by supplying microwaves into the chamber.

15. A surface wave plasma processing apparatus for processing a substrate with surface wave plasma, comprising:
a chamber accommodating the substrate;
a gas supply mechanism configured to supply a gas into the chamber; and
the surface wave plasma source of claim 11 configured to generate the surface wave plasma by supplying microwaves into the chamber.

16. A surface wave plasma processing apparatus for processing a substrate with surface wave plasma, comprising:
a chamber accommodating the substrate;
a gas supply mechanism configured to supply a gas into the chamber; and
the surface wave plasma source of claim 12 configured to generate the surface wave plasma by supplying microwaves into the chamber.

Assignees

• Tokyo Electron Ltd

Inventors

• Mori Kiyoshi
• Osada Yuki
• NAKAGOMI Jun
• Harima Yoshiyuki

Classifications

• H01J37/3222

  Antennas · CPC title

• H05H1/4615

  using surface waves · CPC title

• H05H1/0081

  by electric means · CPC title

• H01J37/32238

  Windows · CPC title

• H01Q1/26

  with electric discharge tube · CPC title