Window and mounting arrangement for twist-and-lock gas injector assembly of inductively coupled plasma chamber

Patent metadata

Field	Value
Publication number	US-9947512-B2
Application number	US-201113280750-A
Country	US
Kind code	B2
Filing date	Oct 25, 2011
Priority date	Oct 25, 2011
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

An improved gas injection assembly for mounting in a central bore of a dielectric window of an inductively coupled plasma chamber includes a window having a central bore and cylindrical recess configured to receive an annular insert having a bayonet opening. The gas injector assembly includes a gas injector, an RF shield surrounding the gas injector, and a faceplate surrounding the RF shield, the faceplate including projections at the bottom thereof for engaging the bayonet opening in the annular insert. The window and gas injection assembly are designed to avoid chipping of the window which is typically made of quartz and in prior mounting arrangements the window has a bayonet opening machined therein. Due to the brittle nature of the quartz material, the machined bayonet opening was subject to chipping when the gas injector assembly was inserted into the bayonet opening.

First claim

What is claimed is:

1. A dielectric window mountable in a plasma processing chamber, the dielectric window comprising:
a disk having a uniform thickness;
a lower vacuum sealing surface of the dielectric window adapted to seal against an upper surface of the plasma processing chamber;
a central bore configured to receive a gas injector configured to deliver a process gas into a center of the plasma processing chamber;
an upper recess in an upper surface surrounding the central bore and configured to receive a portion of the gas injector and an annular insert, wherein the upper recess is defined by a cylindrical sidewall and a planar bottom wall, and wherein the annular insert is configured to secure the portion of the gas injector on the planar bottom wall; and
trenches extending circumferentially in respective outer peripheral portions of the disk,
wherein
each of the trenches is an elongated trench and extends a predetermined length along a periphery of the dielectric window,
each of the trenches has (i) a pair of planar walls, (ii) a curved bottom wall, and (iii) an elongated opening along a circumferential edge of the dielectric window
the elongated opening of each of the trenches has a first end and a second end,
the curved bottom wall of at least one of the trenches has a radially innermost edge,
the radially innermost edge of each of the at least one of the trenches extends linearly from the first end to the second end of the corresponding elongated opening,
the planar walls of each of the trenches are parallel to each other,
the at least one of the trenches extends radially inward away from an outer side surface of the dielectric window, wherein a depth of each of the at least one of the trenches is non-uniform along the corresponding radially innermost edge from the first end to the second end of the corresponding elongated opening,
the planar bottom wall includes vertical mounting holes spaced apart and located between the central bore and the sidewall, and
the vertical mounting holes are configured to secure the annular insert and the gas injector to the planar bottom wall.

2. The dielectric window of claim 1 , further comprising:
a blind hole for receipt of a temperature sensor in the upper surface; and
an indentation on an outer edge of the lower vacuum sealing surface.

3. The dielectric window of claim 1 , wherein the trenches include four circumferentially extending trenches in the outer periphery with midpoints of the four circumferentially extending trenches being spaced 90° apart.

4. The dielectric window of claim 1 , wherein the planar bottom wall of the upper recess includes three vertical mounting holes spaced 120° apart and located midway between the central bore and the cylindrical sidewall.

5. The dielectric window of claim 4 , wherein:
the planar bottom wall is a vacuum sealing surface and includes an alignment hole configured to receive an alignment pin on a lower end of an RF shield of an injector assembly; and
the injector assembly includes the gas injector and the annular insert.

6. The dielectric window of claim 1 , wherein:
the dielectric window has a diameter of 20 inches and a thickness of 1.75 inches;
the lower vacuum sealing surface is an annular vacuum sealing surface that is 1 inch wide and is on an outer bottom portion of the dielectric window; and
the upper recess has a diameter of 3.4 inches and a depth of 0.5 inches; and
the central bore has a diameter of 1 inch.

7. The dielectric window of claim 2 , wherein the blind hole has a diameter of 0.22 inches, a depth of 1.2 inches and a tapered opening with a diameter of 0.48 inches.

8. The dielectric window of claim 4 , wherein:
the mounting holes are located 1.25 inches from a center of the central bore; and
each of the mounting holes has a diameter of 0.4 inches and a depth of 0.5 inches.

9. The dielectric window of claim 5 , wherein the alignment hole is located 0.9 inches from the center of the central bore, has a diameter of 0.09 inches and a depth of 0.15 inches.

10. A dielectric window mountable in a plasma processing chamber, the dielectric window comprising:
a disk having a uniform thickness;
a lower vacuum sealing surface adapted to seal against an upper surface of the plasma processing chamber;
a central bore configured to receive a gas injector, wherein the gas injector delivers process gas into a center of the plasma processing chamber;
an upper recess in an upper surface surrounding the central bore and configured to receive an annular insert, wherein the annular insert is used to mount a gas injector assembly on the dielectric window, wherein the gas injector assembly includes the gas injector;
trenches in an outer periphery of the disk, wherein each of the trenches extends a predetermined length and along a respective peripheral portion of the dielectric window, wherein at least one of the trenches has a non-uniform depth and extends radially inward away from an outer side surface of the dielectric window;
a blind hole configured to receive a temperature sensor in the upper surface; and
an indentation on an outer edge of the lower vacuum sealing surface,
wherein
the trenches include four circumferentially extending trenches in the outer periphery of the dielectric window with midpoints of the four circumferentially extending trenches being spaced 90° apart,
the four circumferentially extending trenches include the at least one of the trenches with the non-uniform depth,
each of the trenches has (i) a pair of planar walls, (ii) a curved bottom wall, and (iii) an elongated opening along a circumferential edge of the dielectric window,
the elongated opening of each of the trenches has a first end and a second end,
the curved bottom wall of each of the at least one of the trenches has a radially innermost edge,
the radially innermost edge of each of the at least one of the trenches extends linearly from the first end to the second end of the corresponding elongated opening,
a depth of each of the at least one of the trenches is non-uniform along the corresponding radially innermost edge from the first end to the second end of the corresponding elongated opening,
the planar walls of each of the trenches are parallel to each other,
the upper recess is defined by a cylindrical sidewall and a planar bottom wall,
the planar bottom wall includes three vertical mounting holes spaced 120° apart and located midway between the central bore and the cylindrical sidewall,
the vertical mounting holes are for securing the annular insert and the gas injector to the upper recess of the dielectric window,
the planar bottom wall is a vacuum sealing surface and includes an alignment hole configured to receive an alignment pin on a lower end of a radio frequency shield of the gas injector assembly,
the gas injector assembly includes the gas injector and the annular insert,
the dielectric window has a diameter of 20 inches and a thickness of 1.75 inches,
the lower vacuum sealing surface is an annular vacuum sealing surface that is 1 inch wide and is on an outer bottom portion of the dielectric window,
the upper recess has a diameter of 3.4 inches and a depth of 0.5 inches,
the central bore has a diameter of 1 inch,
the blind hole has a diameter of 0.22 inches, a depth of 1.2 inches and a tapered opening with a diameter of 0.48 inches,
the mounting holes are located 1.25 inches from the center of the central bore,
each of the mounting holes has a diameter of 0.4 inches and a depth of 0.5 inches,
the alignment hole is located 0.9 inches from the center of the central bore and has a diameter of 0.09 inches and a depth of 0.15 inches,
each of the trenches has a width

Assignees

• Chhatre Rish
• Schaefer David
• Lam Res Corp

Inventors

• Chhatre Rish
• Schaefer David

Classifications

• H01J37/3244

  Gas supply means · CPC title

• H01J37/32119 Primary

  Windows · CPC title

• H01J37/321

  the radio frequency energy being inductively coupled to the plasma · CPC title