Showerhead design to control stray deposition
A lid for a process chamber includes a plate having a first surface and a second surface opposite the first surface. The first surface has a recess and a seal groove formed in the first surface and surrounding the recess. The lid further includes an array of holes extending from the recess to the second surface.
1 . A lid for a process chamber, the lid comprising:
a plate having a first surface and a second surface opposite the first surface, the plate including an axis generally perpendicular to the first surface;
a recess in the first surface, the recess including a sidewall extending at a first acute angle to the axis from an opening at the first surface to a floor within the plate;
a seal groove formed in the first surface and surrounding the opening; and
an array of holes, each hole extending at a second acute angle to the axis from an entrance at the floor of the recess to an exit at a protrusion of the second surface, the protrusion aligned with the recess.
2 . The lid of claim 1 , wherein a cross sectional area of the opening is less than a cross sectional area of the floor.
3 . The lid of claim 1 , wherein the array of holes is arranged as:
a first ring of circumferentially-spaced first holes, each first hole having a first entrance at the floor of the recess and a first exit at the protrusion;
a second ring of circumferentially-spaced second holes, each second hole having a second entrance at the floor of the recess and a second exit at the protrusion; and
wherein:
the first ring has a first radius measured from the axis to the first entrance of each first hole,
the second ring has a second radius measured from the axis to the second entrance of each second hole, and
the second radius is greater than the first radius.
4 . The lid of claim 3 , wherein:
the first ring has a third radius measured from the axis to the first exit of each first hole,
the second ring has a fourth radius measured from the axis to the second exit of each second hole, and
the fourth radius is greater than the third radius.
5 . The lid of claim 1 , wherein the second surface at least partially defines a dome.
6 . The lid of claim 1 , further comprising channels in the first surface, the channels configured to convey a heat exchange fluid.
7 . The lid of claim 1 , wherein the protrusion is frustoconical.
8 . The lid of claim 7 , wherein:
the protrusion includes a side face and an end face; and
the exit of each hole is at the side face.
9 . A lid for a process chamber, the lid comprising:
a plate having a first surface and a second surface opposite the first surface, the first and second surfaces extending laterally to an outer edge of the plate, and the plate including an axis generally perpendicular to the first surface; a recess in the first surface, the recess including a sidewall extending at a first acute angle to the axis from an opening at the first surface to a floor within the plate; a seal groove formed in the first surface; and a showerhead comprising an array of holes extending through the plate, each hole of the array of holes extending at a second acute angle to the axis from an entrance at the floor of the recess to an exit at a protrusion of the second surface, the entrance located radially inward of the seal groove, wherein a maximum radial extent of the showerhead from the axis is 30% or less of a maximum lateral extent of the second surface from the axis.
10 . The lid of claim 9 , wherein the array of holes is arranged as:
a first ring of circumferentially-spaced first holes, each first hole having a first entrance at the floor of the recess and a first exit at the second surface;
a second ring of circumferentially-spaced second holes, each second hole having a second entrance at the floor of the recess and a second exit at the second surface; and
wherein:
the first ring is centered on the axis and has a first radius measured from the axis to the first entrance of each first hole,
the second ring is centered on the axis and has a second radius measured from the axis to the second entrance of each second hole, and
the second radius is greater than the first radius.
11 . The lid of claim 10 , wherein:
the first ring has a third radius measured from the axis to the first exit of each first hole,
the second ring has a fourth radius measured from the axis to the second exit of each second hole, and
the fourth radius is greater than the third radius.
12 . The lid of claim 11 , wherein the plate and showerhead are formed as a unitary structure.
13 . The lid of claim 9 , wherein the second surface at least partially defines a dome.
14 . The lid of claim 9 , wherein the protrusion is frustoconical.
15 . The lid of claim 14 , wherein:
the protrusion includes a side face and an end face; and
the exit of each hole is at the side face.
16 . An assembly, comprising:
a conduit configured to connect to a first gas source; and
a lid including:
a plate having:
a first surface connected to the conduit by a plurality of fixtures including apertures in the first surface or projections from the first surface;
a seal at an interface between the plate and the conduit;
a second surface opposite the first surface;
a recess in the first surface, the recess radially inward of the seal and centered on an axis that is generally perpendicular to the first surface, wherein the recess includes a sidewall extending at a first acute angle to the axis from an opening at the first surface to a floor within the plate; and
a showerhead aligned with the recess and the conduit along the axis, and comprising an array of holes extending at a second acute angle to the axis through the plate from an entrance at the floor of the recess to an exit at a protrusion of the second surface.
17 . The lid of claim 16 , wherein the protrusion is frustoconical.
18 . The lid of claim 17 , wherein:
the protrusion includes a side face and an end face; and
the exit of each hole is at the side face.