U.S. patent application number 16/875750 was filed with the patent office on 2021-11-18 for floating pin for substrate transfer.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Thomas BREZOCZKY, Bhaskar PRASAD, Kirankumar Neelasandra SAVANDAIAH, Sreenath SOVENAHALLI, Srinivasa Rao YEDLA.
Application Number | 20210358797 16/875750 |
Document ID | / |
Family ID | 1000004914427 |
Filed Date | 2021-11-18 |
United States Patent
Application |
20210358797 |
Kind Code |
A1 |
SOVENAHALLI; Sreenath ; et
al. |
November 18, 2021 |
FLOATING PIN FOR SUBSTRATE TRANSFER
Abstract
A floating pin for positioning a substrate relative to a
substrate support includes a shaft configured to move through a
guide hole in a substrate support, and a pin head including a top
surface and a flat shoulder surface disposed between the top
surface and the shaft. The flat shoulder surface is configured to
be seated on a recessed surface of the substrate support and seal
the guide hole of the substrate support.
Inventors: |
SOVENAHALLI; Sreenath;
(Bangalore, IN) ; SAVANDAIAH; Kirankumar Neelasandra;
(Bangalore, IN) ; PRASAD; Bhaskar; (Adityapur,
IN) ; YEDLA; Srinivasa Rao; (Bangalore, IN) ;
BREZOCZKY; Thomas; (Los Gatos, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
1000004914427 |
Appl. No.: |
16/875750 |
Filed: |
May 15, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/68742
20130101 |
International
Class: |
H01L 21/687 20060101
H01L021/687 |
Claims
1. A floating pin for positioning a substrate relative to a
substrate support, the floating pin comprising: a shaft configured
to move through a guide hole in a substrate support; and a pin head
comprising a top surface and a flat shoulder surface disposed
between the top surface and the shaft, wherein the flat shoulder
surface is configured to be seated on a recessed surface of the
substrate support and seal the guide hole of the substrate
support.
2. The floating pin of claim 1, wherein: the flat shoulder surface
has a diameter of between 8.9 mm and 9.1 mm, and the shaft has a
diameter of between 3.225 mm and 3.285 mm, having a clearance to
interior sidewall surface of the guide hole of between 0.3 mm and
0.4 mm.
3. The floating pin of claim 1, wherein the pin head comprises: a
shoulder portion that includes the flat shoulder surface; and a
countersunk portion that includes the top surface having a larger
diameter than the flat shoulder surface, the countersunk portion
having a beveled surface extending from an exterior sidewall
surface of the shoulder portion to the top surface.
4. The floating pin of claim 3, wherein: the flat shoulder surface
has a diameter of between 8.9 mm and 9.1 mm, the top surface has a
diameter of between 11.1 mm and 11.2 mm, and the shaft has a
diameter of between 3.225 mm and 3.285 mm, having a clearance to
interior sidewall surface of the guide hole of between 0.3 mm and
0.4 mm.
5. The floating pin of claim 1, wherein the shaft comprises
aluminum oxide.
6. The floating pin of claim 1, further comprising: a dead weight
disposed at an end of the shaft opposite the pin head.
7. The floating pin of claim 6, wherein the dead weight comprises
stainless steel and weighs between 13 g and 20 g.
8. A lift pin assembly for positioning a substrate relative to a
substrate support, the lift pin assembly comprising: a floating pin
having a pin head and a shaft; and a lift pin configured to contact
an end of the shaft opposite the pin head and move the shaft
through a guide hole in the substrate support, wherein: the pin
head comprises a top surface and a flat shoulder surface disposed
between the top surface and the shaft, and the flat shoulder
surface is configured to be seated on a recessed surface of the
substrate support and seal the guide hole of the substrate
support.
9. The lift pin assembly of claim 8, wherein: the flat shoulder
surface has a diameter of between 8.9 mm and 9.1 mm, and the shaft
has a diameter of between 3.225 mm and 3.285 mm, having a clearance
to interior sidewall surface of the guide hole of between 0.3 mm
and 0.4 mm.
10. The lift pin assembly of claim 8, wherein the pin head
comprises: a shoulder portion that includes the flat shoulder
surface; and a countersunk portion that includes the top surface
having a larger diameter than the flat shoulder surface, the
countersunk portion having a beveled surface extending from an
exterior sidewall surface of the shoulder portion to the top
surface.
11. The lift pin assembly of claim 10 wherein: the flat shoulder
surface has a diameter of between 8.9 mm and 9.1 mm, the top
surface has a diameter of between 11.1 mm and 11.2 mm, and the
shaft has a diameter of between 3.225 mm and 3.285 mm, having a
clearance to interior sidewall surface of the guide hole of between
0.3 mm and 0.4 mm.
12. The lift pin assembly of claim 8, wherein: the shaft comprises
aluminum oxide, and the lift pin comprises stainless steel.
13. The lift pin assembly of claim 8, further comprising: a dead
weight disposed at an end of the shaft opposite the pin head.
14. The lift pin assembly of claim 13, wherein the dead weight
comprises stainless steel and weighs between 13 g and 20 g.
15. A processing system, comprising: a substrate support having a
guide hole therethrough, the guide hole comprising a seating
portion and a guide portion, wherein the seating portion comprises
a flat shoulder surface between a front-side surface of the
substrate support and the guide portion; and a lift pin assembly
comprising: a floating pin having a pin head configured to be
seated in the seating portion and a shaft configured to move
through the guide portion; and a lift pin configured to contact an
end of the shaft opposite the pin head and move the floating pin
through the guide hole in the substrate support, wherein: the pin
head comprises a top surface and a flat shoulder surface disposed
between the top surface and the shaft, and the flat shoulder
surface of the pin head is configured to be seated on the flat
shoulder surface of the seating portion and seal the guide hole of
the substrate support.
16. The processing system of claim 15, wherein: the flat shoulder
surface of the pin head has a diameter of between 8.9 mm and 9.1
mm, the shaft has a diameter of between 3.225 mm and 3.285 mm, the
flat shoulder surface of the seating portion has a diameter of
between 10.6 mm and 10.8 mm, and the guide portion has a diameter
of between about 3.95 mm and about 4.05 mm.
17. The processing system of claim 15, wherein the pin head
comprises: a shoulder portion that includes the flat shoulder
surface; and a countersunk portion that includes the top surface
having a larger diameter than the flat shoulder surface, the
countersunk portion having a beveled surface extending from an
exterior sidewall surface of the shoulder portion to the top
surface.
18. The processing system of claim 17, wherein: the flat shoulder
surface has a diameter of between 8.9 mm and 9.1 mm, the top
surface has a diameter of between 11.1 mm and 11.2 mm, the shaft
has a diameter of between 3.225 mm and 3.285 mm, having a clearance
to interior sidewall surface of the guide hole of between 0.3 mm
and 0.4 mm, the flat shoulder surface of the seating portion has a
diameter of between 12.6 mm and 12.8 mm, and the guide portion has
a diameter of between about 3.95 mm and about 4.05 mm.
19. The processing system of claim 15, wherein: the shaft comprises
aluminum oxide, and the lift pin comprises stainless steel.
20. The processing system of claim 15, further comprising: a dead
weight disposed at an end of the shaft opposite the pin head,
wherein the dead weight comprises stainless steel and weighs
between 13 g and 20 g.
Description
FIELD
[0001] Embodiments of the present disclosure generally relate to
methods and apparatuses for processing semiconductor substrates.
More particularly, embodiments of the disclosure relate lift pin
assemblies for positioning a substrate relative to a substrate
support.
BACKGROUND
[0002] Conventional semiconductor substrate processing tools (e.g.,
a cluster tool) are configured to perform one or more processes
during substrate processing. For example, a cluster tool can
include a physical vapor deposition (PVD) configured to perform a
PVD process on a substrate, an atomic layer deposition (ALD)
chamber configured to perform an ALD process on a substrate, a
chemical vapor deposition (CVD) chamber configured to perform a CVD
process on a substrate, etc., and/or one or more other processing
chambers, e.g., a preclean process chamber. The cluster tool can
include a robot to move the substrate(s) to/from the various
processing chambers, buffer chambers and/or load locks coupled to
the mainframe of the cluster tool.
[0003] While such semiconductor substrate processing tools (i.e.,
cluster tools) are suitable for processing a substrate or multiple
substrates, a process gas leaks from a substrate support that has
guide holes to accommodate lift pins. Lift pins are used for
transferring a substrate from a robot arm onto the substrate
support. Such process gas leakage may impact a thermal contact
resistance between a substrate and a substrate support on which the
substrate is deposited, leading to improper and non-uniform
chucking of the substrate to the substrate support during substrate
processing. Existing lift pins are enabled only to transfer a
substrate to a substrate support without providing any type of
sealing to avoid process gas leakage.
[0004] Therefore, there is a need in the art for lift pins that
transfer a substrate to a substrate support and provide sealing to
reduce process gas leakage through the substrate support.
SUMMARY
[0005] Embodiments described herein provide a floating pin for
positioning a substrate relative to a substrate support. A floating
pin includes a shaft configured to move through a guide hole in a
substrate support, and a pin head including a top surface and a
flat shoulder surface disposed between the top surface and the
shaft. The flat shoulder surface is configured to be seated on a
recessed surface of the substrate support and seal the guide hole
of the substrate support.
[0006] Embodiments described herein also provide a lift pin
assembly for positioning a substrate relative to a substrate
support. A lift pin assembly includes a floating pin having a pin
head and a shaft, and a lift pin configured to contact an end of
the shaft opposite the pin head and move the shaft through a guide
hole in the substrate support. The pin head includes a top surface
and a flat shoulder surface disposed between the top surface and
the shaft, and the flat shoulder surface is configured to be seated
on a recessed surface of the substrate support and seal the guide
hole of the substrate support.
[0007] Embodiments described herein also provide a processing
system. A processing system includes a substrate support having a
guide hole therethrough and a lift pin assembly. The guide hole
includes a seating portion and a guide portion. The seating portion
includes a flat shoulder surface between a front-side surface of
the substrate support and the guide portion. A lift pin assembly
includes a floating pin having a pin head configured to be seated
in the seating portion and a shaft configured to move through the
guide portion. A lift pin is configured to contact an end of the
shaft opposite the pin head and move the floating pin through the
guide hole in the substrate support. The pin head includes a top
surface and a flat shoulder surface disposed between the top
surface and the shaft, and the flat shoulder surface of the pin
head is configured to be seated on the flat shoulder surface of the
seating portion and seal the guide hole of the substrate
support.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] So that the manner in which the above recited features of
the present disclosure can be understood in detail, a more
particular description of the disclosure, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only exemplary embodiments
and are therefore not to be considered limiting of its scope, and
may admit to other equally effective embodiments.
[0009] FIG. 1 is a top plan view of a system according to one
embodiment.
[0010] FIG. 2 is a cross-sectional view of a processing system
according to one embodiment.
[0011] FIG. 3 is a schematic view of a floating pin according to
one embodiment.
[0012] FIG. 4 is a schematic view of a floating pin according to
one embodiment.
[0013] FIG. 5 is a schematic view of a floating pin according to
one embodiment.
[0014] FIG. 6 is a schematic view of a floating pin according to
one embodiment.
[0015] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
and features of one embodiment may be beneficially incorporated in
other embodiments without further recitation.
DETAILED DESCRIPTION
[0016] Embodiments of apparatus and systems for substrate
processing are provided herein. Particularly, some embodiments are
directed to a lift pin assembly that includes a floating pin and a
lift pin that moves the floating pin through a guide hole of a
substrate support. The floating pin described below includes a pin
head having a flat shoulder that is seated on a recessed surface of
the substrate support and seals the guide hole of the substrate
support. This sealing prevents gas leakage through the guide hole
and thus maintains the process pressure within a processing
chamber. In some embodiments, the pin head also has a countersunk
portion above the flat shoulder surface and provides further
sealing of the guide hole.
[0017] FIG. 1 is a top plan view of a system 100 in accordance with
at least some embodiments of the disclosure. The system 100
includes a front-end module 110, an interface module 120, and a
pair of load locks 130 (hereinafter referred to as the load locks
130). The system also includes a buffer (or vacuum transfer)
chamber 140 and a plurality (e.g., three) of multi environment
chambers 150a-150c including a plurality of processing chambers
160a-160d (hereinafter the processing chambers 160), and/or
enclosed areas 170a and 170b (hereinafter the enclosed areas
170).
[0018] FIG. 2 depicts a cross-sectional view of a processing system
200 that includes any processing chamber described above with
respect to FIG. 1. The processing system 200 generally comprises a
chamber body 202 coupled to a gas source 204. The chamber body 202
is typically a unitary machined structure fabricated from a rigid
block of material such as aluminum. Within the chamber body 202 is
a showerhead 206 and a substrate support assembly 210. The
showerhead 206 is coupled to the upper surface or lid of the
chamber body 202 and provides a uniform flow of gas from the gas
source 204 that is dispersed over a substrate 208 positioned on a
substrate support assembly 210.
[0019] The substrate support assembly 210 generally includes a
substrate support 212 and a stem 214. The stem 214 positions the
substrate support 212 within the chamber body 202. A substrate 208
is placed upon the substrate support 212 during processing. The
substrate support 212 may be a susceptor, a heater, an
electrostatic chuck or a vacuum chuck. Typically, the substrate
support 212 is fabricated from a material selected from ceramic,
aluminum, stainless steel, and combinations thereof. The substrate
support 212 has a plurality of guide holes 216 disposed
therethrough. Each guide hole 216, or alternatively an inner
passage of a guide bushing disposed within the guide hole 216 (such
as a through-hole 306 in a bush mechanism 304 shown in FIG. 3)
accommodates a floating pin 218 of a lift pin assembly 220.
[0020] The lift pin assembly 220 interacts with the substrate
support 212 to position the substrate 208 relative to the substrate
support 212. The lift pin assembly 220 includes the floating pins
218, a lift plate 222 with a lift pin 224 disposed thereon, a stem
226 connected to the lift plate 222, and a lifting mechanism 228,
such as an actuator, for controlling the elevation of the lift
plate 222. The elevation of the stem 226 is controlled by the
lifting mechanism 228. The lifting mechanism 228 may be a pneumatic
cylinder, hydraulic cylinder, lead screw, solenoid, stepper motor,
or other motion device that is typically positioned outside of the
chamber body 202 and adapted to move the stem 226. As the stem 226
and the lift plate 222 connected to the stem 226 are moved upward
towards the substrate support 212, the lift pin 224 mounted on the
lift plate 222 contacts the lower end of the floating pin 218 to
move the floating pin 218 through the guide hole 216 of the
substrate support 212. The upper end of the floating pin 218 exits
the guide hole 216 of the substrate support 212 and lift the
substrate 208 into a spaced-apart relation relative to the
front-side surface 212a of the substrate support 212.
[0021] The floating pin 218 is typically formed of ceramic,
stainless steel, aluminum, aluminum nitride, aluminum oxide,
sapphire, or other suitable material. In some embodiments, the
floating pin 218 is formed of aluminum nitride (AlN). Floating pins
formed of AIN improves lift pin thermal dissipation capacity due to
its higher thermal conductivity. If desired, the floating pins 218
may be AlN containing yttrium oxide (Y.sub.2O.sub.3) of about 2 wt
% to about 5 wt % to further enhance the thermal conductivity. A
cylindrical outer surface of the floating pin 218 may additionally
be treated to reduce friction and surface wear. For example, the
cylindrical outer surface of the floating pin 218 may be plated,
plasma flame sprayed, or electropolished to reduce friction, alter
the surface hardness, improve smoothness, or improve resistance to
scratching and corrosion. The lift pins 224 may be formed of
stainless steel (SST).
[0022] FIG. 3 illustrates a telescopic floating pin 302 that may be
used as the floating pins 218 in FIG. 2. A bush mechanism 304 is
fitted at least partially in the guide hole 216 of the substrate
support 212 and bonded to a back-side surface 212b of the substrate
support 212. The bush mechanism 304 has a through-hole 306. The
bush mechanism 304 may be made of ceramic. The telescopic pin 302
has a pin head 308 and a shaft 310. The pin head 308 has a rounded
tip 312, which contacts a substrate 208 when the telescopic
floating pin 302 is pushed up to lift the substrate 208. The pin
head 308 has a larger lateral diameter than the shaft 310. The
shaft 310 extends through the through-hole 306 of the bush
mechanism 304. The telescopic floating pin 302 has a beveled
surface 314 from the pin head 308 to the shaft 310.
[0023] The bush mechanism 304 has an insert portion 318 and a
flange portion 320. The insert portion 318 is inserted into the
guide hole 216 of the substrate support 212 from the back-side
surface 212b of the substrate support 212, and the flange portion
320 contacts (and forms a seal with) the back-side surface 212b of
the substrate support 212. The bush mechanism 304 may be secured to
the substrate support 212 by, for example, screws through the
flange portion 320 screwed into the substrate support 212. The
exterior sidewall surface of the insert portion 318 can contact a
sidewall surface of the guide hole 216, although some gap
therebetween may occur.
[0024] The insert portion 318 also has a beveled surface 316
extending from the exterior sidewall surface of the insert portion
318 to an interior sidewall surface of the through-hole 306 of the
bush mechanism 304. The beveled surface 316 of the insert portion
318 generally corresponds with the beveled surface 314 of the
telescopic floating pin 302. In a retracted position when a
substrate 208 rests on the front-side surface 212a of the substrate
support 212, the two beveled surfaces 314, 316 mate. The contacting
of the flange portion 320 to the back-side surface 212b of the
substrate support 212 and mating of the two beveled surfaces 314,
316 create a seal through the guide hole 216, which reduces gas
leakage and particle contamination through the substrate support
212 and thus maintains the pressure within the processing chamber
during processing.
[0025] In the retracted position, the corresponding lift pin 224 is
not providing a lifting force to the telescopic floating pin 302
and may be separated from the telescopic floating pin 302. In this
position, no force other than a gravitational force is acting on
the telescopic floating pin 302. The gravitational force causes the
telescopic floating pin 302 to be retracted such that the beveled
surface 314 of the telescopic floating pin 302 is seated on and
mates with the beveled surface 316 of the insert portion 318 of the
bush mechanism 304. This creates a seal as described above. In this
position, the rounded tip 312 is entirely below a surface of the
substrate support 212 on which a substrate 208 can rest.
[0026] To lift a substrate 208 from the front-side surface 212a of
the substrate support 212, the lifting mechanism 228 elevates the
lift plate 222 on which the lift pin 224 is disposed, which causes
the lift pin 224 to enter an internal cut-out 322 and move upward
in direction 324. Further upward movement of the lift pin 224
provides an upward force to the telescopic floating pin 302 such
that the pin head 308 of the telescopic floating pin 302 exits the
guide hole 216 of the substrate support 212. Extension of the
telescopic floating pin 302 above the front-side surface 212a of
the substrate support 212 causes the rounded tip 312 to contact a
backside surface of the substrate 208 and lift the substrate 208
from the front-side surface 212a of the substrate support 212.
[0027] Thereafter, the lifting mechanism 228 moves the lift plate
222 downward, which causes the lift pins 224 to move downward.
Downward movement of the lift pin 224 removes the previously
applied upward force to the telescopic floating pin 302 such that
the gravitational force acting on the telescopic floating pin 302
causes the telescopic floating pin 302 to return to the retracted
position, where the beveled surface of the telescopic floating pin
302 is seated on and mates with the beveled surface of the insert
portion 318 of the bush mechanism 304.
[0028] A number of other examples of floating pins 218 are
described below. Some examples use surfaces of the guide hole 216
recessed from the front-side surface 212a of the substrate support
212 to form a seal with the floating pin 218. A bush mechanism 304
may be omitted. Various configurations of mating surfaces that form
a seal and various configurations of a head of the floating pin 218
are described below. Any aspect of these configurations can be
combined with any other aspect of another configuration. A person
having ordinary skill in the art will readily envision
modifications and combinations that can be achieved and are
contemplated within the scope of other examples.
[0029] FIG. 4 illustrates an example floating pin 402 that may be
used as the floating pins 218 in FIG. 2. The floating pin 402 has a
countersunk pin head 408 and a shaft 410. The countersunk pin head
408 has a top surface 412 that includes a flat surface, a rounded
surface, a conical surface, the like, or a combination of these
surfaces. The countersunk pin head 408 contacts a substrate 208
when the floating pin 402 is pushed up to lift the substrate 208.
The top surface 412 of the countersunk pin head 408 has a larger
lateral diameter than the shaft 410 of the floating pin 402. The
countersunk pin head 408 has a beveled surface 414 extending from
the top surface 412 of the countersunk pin head 408 to the shaft
410 of the floating pin 402.
[0030] The guide hole 216 of the substrate support 212 includes a
seating portion (also referred to as an opening of the substrate
support 212) 216a that accommodates the countersunk pin head 408,
and a guide portion 216b that accommodates the shaft 410. The
seating portion 216a has a beveled surface 416 extending from the
front-side surface 212a of the substrate support 212 to an interior
sidewall surface of the guide portion 216b of the guide hole 216.
For example, the beveled surface 416 may be a result of
countersinking the guide hole 216. The beveled surface 416 of the
seating portion 216a generally corresponds with the beveled surface
414 of the countersunk pin head 408. In a retracted position, the
two beveled surfaces 414, 416 mate. The mating of the two beveled
surfaces 414, 416 creates a seal through the guide hole 216, which
reduces gas leakage and particle contamination through the
substrate support 212 during processing. The floating pin 402 can
be caused to be in a retracted position and can be caused to extend
from the surface of the substrate support 212 like described above
with respect to the telescopic floating pin 302 of FIG. 3.
[0031] FIG. 5 illustrates an example floating pin 502 that may be
used as the floating pins 218 in FIG. 2. The floating pin 502 has a
shoulder pin head 508 and a shaft 510. The shoulder pin head 508
has a top surface 512 that includes a flat surface, a rounded
surface, a conical surface, the like, or a combination of these
surfaces. The shoulder pin head 508 contacts a substrate 208 when
the floating pin 502 is pushed up to lift the substrate 208. The
shoulder pin head 508 has a larger lateral diameter than the shaft
510 of the floating pin 502. The shaft 510 extends through the
guide hole 216 of the substrate support 212. The shoulder pin head
508 has a flat shoulder surface 514 from the exterior edges of the
shoulder pin head 508 to the shaft 510 of the floating pin 502.
[0032] The guide hole 216 of the substrate support 212 includes a
seating portion 216a that accommodates the shoulder pin head 508,
and a guide portion 216b that accommodates the shaft 510. The
seating portion 216a has a flat shoulder surface 516 recessed below
the front-side surface 212a of the substrate support 212. This flat
shoulder surface 516 is also referred to as a recessed surface of
the substrate support 212. The flat shoulder surface 516 of the
seating portion 216a generally corresponds with the flat shoulder
surface 514 of the shoulder pin head 508. In a retracted position,
the two flat shoulder surfaces 514, 516 mate. The mating of the two
flat shoulder surfaces 514, 516 creates a seal through the guide
hole 216, which reduces gas leakage and particle contamination
through the substrate support 212 during processing.
[0033] The seating portion 216a of the guide hole 216 has a
diameter larger than a diameter of the shoulder pin head 508 such
that the shoulder pin head 508 does not touch the interior sidewall
surface of the seating portion 216a even when the floating pin 502
moves upward and downward slightly tilted with respect to the guide
hole 216. The guide portion 216b of the guide hole 216 has a
diameter larger than a diameter of the shaft 510 to allow movement
of the shaft 510 through the guide portion 216b. A clearance
between the shaft 510 and the interior sidewall surface of the
guide portion 216b is sealed by the flat shoulder surface 514 of
the shoulder pin head 508, since the flat shoulder surface 514 has
a large enough diameter to cover the clearance. In a case where the
centerline of the floating pin 502 is misaligned (i.e., tilted)
with respect to the centerline of the guide hole 216, the
gravitational force causes the floating pin 502 to be retracted
such that the shoulder pin head 508 is positioned within the
seating portion 216a and the flat shoulder surface 514 of the
shoulder pin head 508 is seated against the flat shoulder surface
516 of the seating portion 216a of the guide hole 216. In some
embodiments, to enhance the retraction of the floating pin 502 that
is misaligned and sealing of the clearance between the shaft 510
and the interior sidewall surface of the guide hole 216, a dead
weight 522 is added at the lower end (i.e., on the opposite side of
the shoulder pin head 508) of the shaft 510. The dead weight 622
may be made of Stainless Steel 316 (SS 316) and weigh between about
13 g and about 20 g.
[0034] In some embodiments, the flat shoulder surface 516 of the
seating portion 216a of the guide hole 216 has a diameter of
between about 10.6 mm and about 10.8 mm, such as about 10.8 mm, and
the guide portion 216b of the guide hole 216 has a diameter of
between about 3.95 mm and about 4.05 mm, such as about 4 mm. The
flat shoulder surface 514 of the shoulder pin head 518 has a
diameter of between about 8.9 mm and about 9.1 mm, such as about 9
mm, and the shaft 510 of the floating pin 502 has a diameter of
between about 3.225 mm and about 3.285 mm, such as about 3.25 mm,
allowing a clearance to the interior sidewall surface of the guide
portion 216b of the guide hole 216 of between about 0.3 mm and
about 0.4 mm, such as about 0.34 mm.
[0035] The floating pin 502 can be caused to be in a retracted
position and can be caused to extend from the surface of the
substrate support 212 like described above with respect to the
telescopic floating pin 302 of FIG. 3.
[0036] FIG. 6 illustrates an example floating pin 602 that may be
used as the floating pins 218 in FIG. 2. The floating pin 602 has a
shouldered countersunk pin head 608 and a shaft 610. The shouldered
countersunk pin head 608 has a top surface 612 that includes a flat
surface, a rounded surface, a conical surface, the like, or a
combination of these surfaces. The shouldered countersunk pin head
608 contacts a substrate 208 when the floating pin 602 is pushed up
to lift the substrate 208. The shouldered countersunk pin head 608
includes a shoulder portion 618 and a countersunk portion 620. The
top surface 612 of the shouldered countersunk pin head 608 has a
larger lateral diameter than the shoulder portion 618, and the
shoulder portion 618 has a larger lateral diameter of the shaft 610
of the floating pin 602. The shoulder portion 618 of the shouldered
countersunk pin head 608 has a flat shoulder surface 614a extending
from the shaft 610 of the floating pin 602 to the exterior sidewall
surface of the shoulder portion 618 of the shouldered countersunk
pin head 608. The countersunk portion 620 of the shouldered
countersunk pin head 608 has a beveled surface 614b extending from
the exterior surface of the shoulder portion 618 to the top surface
612 of the shouldered countersunk pin head 608.
[0037] The guide hole 216 of the substrate support 212 includes a
seating portion 216a that accommodates the shouldered countersunk
pin head 608, and a guide portion 216b that accommodates the shaft
610. The seating portion 216a includes a flat shoulder surface 616a
recessed below the front-side surface 212a of the substrate support
212. This flat shoulder surface 616a is also referred to as a
recessed surface of the substrate support 212. The seating portion
216a further includes a beveled surface 616b between the flat
shoulder surface 616a and the front-side surface 212a of the
substrate support 212. This beveled surface 616b is also referred
to as a beveled surface of the substrate support 212. The beveled
surface 616b of the seating portion 216a generally corresponds with
the beveled surface 614b of the countersunk portion 620 of the
shouldered countersunk pin head 608. The flat shoulder surface 616a
of the seating portion 216a generally corresponds with the flat
shoulder surface 614a of the shoulder portion 618 of the shouldered
countersunk pin head 608. In a retracted position, the two beveled
surfaces 614b, 616b and/or the two flat shoulder surfaces 614a,
616a mate. The mating of the two beveled surfaces 614b, 616b and/or
the two flat shoulder surfaces 614a, 616a creates a seal through
the guide hole 216, which reduces gas leakage and particle
contamination through the substrate support 212 during
processing.
[0038] The seating portion 216a of the guide hole 216 has a
diameter larger than a diameter of the shouldered countersunk pin
head 608 such that the shouldered countersunk pin head 608 does not
touch the interior sidewall surface of the seating portion 216a
even when the floating pin 602 moves upward and downward slightly
tilted with respect to the guide hole 216. The guide portion 216b
of the guide hole 216 has a diameter larger than a diameter of the
shaft 610 to allow movement of the shaft 610 through the guide
portion 216b. A clearance between the shaft 610 and the interior
sidewall surface of the guide portion 216b is sealed by the flat
shoulder surface 614a of the shoulder portion 618 of the shouldered
countersunk pin head 608, since the flat shoulder surface 614a has
a large enough diameter to cover the clearance. The beveled surface
614b of the countersunk portion 620 of the shouldered countersunk
pin head 608 provides further sealing of the clearance between the
shaft 610 and the interior sidewall surface of the guide portion
216b.
[0039] In a case where the centerline of the floating pin 602 is
misaligned (i.e., tilted) with respect to the centerline of the
guide hole 216, the gravitational force causes the floating pin 602
to be retracted such that the shouldered countersunk pin head 608
is positioned within the seating portion 216a and the flat shoulder
surface 614a of the shoulder portion 618 of the shouldered
countersunk pin head 608 is seated against the flat shoulder
surface 616a of the seating portion 216a of the guide hole 216. In
some embodiments, to enhance the retraction of the floating pin 602
that is misaligned and sealing of the clearance between the shaft
610 and the interior sidewall surface of the guide hole 216, a dead
weight 622 is added at the lower end (i.e., on the opposite side of
the shouldered countersunk pin head 608) of the shaft 610. The dead
weight 622 may be made of Stainless Steel 316 (SS 316) and weigh
between about 13 g and about 20 g.
[0040] In some embodiments, the seating portion 216a of the guide
hole 216 at the front-side surface 212a of the substrate support
212 has a diameter of between about 12.6 mm and about 12.8 mm, such
as about 12.7 mm. The flat shoulder surface 616 of the seating
portion 216a of the guide hole 216 has a diameter of between about
10.6 mm and about 10.8 mm, such as about 10.8 mm, and the guide
portion 216b of the guide hole 216 has a diameter of between about
3.95 mm and about 4.05 mm, such as about 4 mm. The top surface 612
of the shouldered countersunk pin head 608 has a diameter of
between about 11.1 mm and about 11.2 mm, such as about 11.2 mm. The
flat shoulder surface 614a of the shoulder portion 618 of the
shouldered countersunk pin head 608 has a diameter of between about
8.9 mm and about 9.1 mm, such as about 9 mm, and the shaft 610 of
the floating pin 602 has a diameter of between about 3.225 mm and
about 3.285 mm, such as about 3.25 mm, allowing a clearance to the
interior sidewall surface of the guide portion 216b of the guide
hole 216 of between about 0.3 mm and about 0.4 mm, such as about
0.34 mm.
[0041] The floating pin 602 can be caused to be in a retracted
position and can be caused to extend from the surface of the
substrate support 212 like described above with respect to the
telescopic floating pin 302 of FIG. 3.
[0042] Benefits of the present disclosure include an improved
floating pin for positioning a substrate relative to a substrate
support in a substrate processing system. The floating pin has a
flat shoulder surface that is seated on a recessed surface of the
substrate support and seal a guide hole formed to guide the
floating pin in the substrate support. This sealing prevents gas
leak from the guide hole and thus maintains the pressure within the
substrate processing system.
[0043] While the foregoing is directed to embodiments of the
present disclosure, other and further embodiments of the disclosure
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
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