U.S. patent application number 15/342582 was filed with the patent office on 2017-08-24 for method and apparatus for supplying ion beam in ion implantation process.
The applicant listed for this patent is Taiwan Semiconductor Manufacturing Co., Ltd.. Invention is credited to Jen-Chung CHIU, Tai-Kun KAO, Tsung-Min LIN.
Application Number | 20170243719 15/342582 |
Document ID | / |
Family ID | 59581287 |
Filed Date | 2017-08-24 |
United States Patent
Application |
20170243719 |
Kind Code |
A1 |
KAO; Tai-Kun ; et
al. |
August 24, 2017 |
METHOD AND APPARATUS FOR SUPPLYING ION BEAM IN ION IMPLANTATION
PROCESS
Abstract
A method for generating an ion beam in an ion implantation
process is provided. The method includes supplying a working gas
into a first portion of an arc chamber which is separated from a
second portion of the arc chamber by an intermediate plate. The
method further includes guiding the working gas into the second
portion of the arc chamber via a plurality of gas outlets formed at
two opposite edges of the intermediate plate. The method also
includes generating an ion beam from the working gas in the second
portion of the arc chamber.
Inventors: |
KAO; Tai-Kun; (Hsinchu City,
TW) ; LIN; Tsung-Min; (Zhubei City, TW) ;
CHIU; Jen-Chung; (Hsinchu City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Taiwan Semiconductor Manufacturing Co., Ltd. |
Hsinchu |
|
TW |
|
|
Family ID: |
59581287 |
Appl. No.: |
15/342582 |
Filed: |
November 3, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62297167 |
Feb 19, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01J 37/08 20130101;
H01L 21/26513 20130101; H01J 37/3171 20130101; H01J 2237/006
20130101 |
International
Class: |
H01J 37/317 20060101
H01J037/317; H01J 37/08 20060101 H01J037/08; H01L 21/265 20060101
H01L021/265 |
Claims
1. An ion beam generator used in a semiconductor processing system,
comprising: an arc chamber, comprising: a lower wall, wherein a
first recess is formed on the lower wall, and a second recess is
formed at a bottom surface of the first recess, and a through hole
is formed at a bottom surface of the second recess; a side wall
connected the lower wall; and an intermediate plate positioned in
the first recess and comprising a plurality of gas outlets formed
on two opposite edges of the intermediate plate; a gas supply
connected to the through hole to supply gas into a gas reservoir
defined by the intermediate plate and the second recess; and a
filament and an electrode respectively positioned in two sides of
the side wall for generating an ion plasma.
2. The ion beam generator as claimed in claim 1, wherein the gas
outlets are arranged in first and second groups respectively lying
along two opposite long sides of the intermediate plate, and each
of the first and second group consists of three gas outlets spaced
apart by a predetermined pitch.
3. The ion beam generator as claimed in claim 2, wherein the first
and the third gas outlets in each of the first and second groups
are respectively spaced apart from two opposite short sides of the
intermediate plate by the same predetermined pitch.
4. The ion beam generator as claimed in claim 1, wherein the gas
outlets are generally symmetrically spaced about the center of the
intermediate plate.
5. The ion beam generator as claimed in claim 1, wherein a portion
of each gas outlet is covered by the bottom surface of the first
recess.
6. The ion beam generator as claimed in claim 1, wherein each of
the gas outlets is arranged to correspond to a side surface of the
second recess that connects the bottom surface of the first recess
to the bottom surface of the second recess.
7. The ion beam generator as claimed in claim 1, wherein each of
the gas outlets possesses a width ranging from about 3.5 mm to
about 6.0 mm.
8. An ion beam generator used in a semiconductor processing system,
comprising: an arc chamber comprising: a lower wall; a side wall
connected to the lower wall; an intermediate plate positioned on
the lower wall and comprising six gas outlets, wherein each of two
opposite long sides of the intermediate plate is divided equally
into four segments by three reference points, the six outlets are
arranged to correspond to the six reference points; a gas supply
connected to the arc chamber to supply gas into a gas reservoir
immediately underneath the intermediate plate; and a filament and
an electrode respectively positioned in two sides of the side wall
for generating an ion plasma.
9. The ion beam generator as claimed in claim 8, wherein a first
recess is formed in a top surface of the lower wall, a second
recess is formed at a bottom surface of the first recess, and a
through hole is formed at a bottom surface of the second recess;
wherein the intermediate plate is positioned in the first recess,
and the gas supply is connected to the through hole.
10. The ion beam generator as claimed in claim 9, wherein a portion
of each gas outlet is covered by the bottom surface of the first
recess.
11. The ion beam generator as claimed in claim 9, wherein each of
the gas outlets is arranged to correspond to a side surface of the
second recess that connects the bottom surface of the first recess
to the bottom surface of the second recess.
12. The ion beam generator as claimed in claim 8, wherein a top
surface of the intermediate plate and a top surface of the lower
wall are the same height.
13. The ion beam generator as claimed in claim 8, wherein the gas
outlets are generally symmetrically spaced about the center of the
intermediate plate.
14. The ion beam generator as claimed in claim 8, wherein each of
the gas outlets possesses a width ranging from about 3.5 mm to
about 6.0 mm.
15. A method, comprising: supplying a working gas into a first
portion of an arc chamber which is separated from a second portion
of the arc chamber by an intermediate plate; guiding the working
gas into the second portion of the arc chamber via a plurality of
gas outlets formed at two opposite edges of the intermediate plate;
and generating an ion beam from the working gas in the second
portion of the arc chamber.
16. The method as claimed in claim 15, wherein the arc current
applied to the filament ranges from about 150 A to about 170 A.
17. The method as claimed in claim 15, wherein the working gas is
supplied to the arc chamber at a pressure from about 1.0 Torr to
about 4.0 Torr.
18. The method as claimed in claim 15, wherein the working gas
passes through each of the gas outlets at the same flow rate.
19. The method as claimed in claim 15, wherein guiding the working
gas into the second portion of the arc chamber via the plurality of
gas outlets comprises guiding the working gas along a direction
that is perpendicular to the immediate plate by a side wall of the
first portion of the arc chamber.
20. The method as claimed in claim 15, wherein the working gas
comprises boron trifluoride, phosphine, and arsine.
Description
PRIORITY CLAIM AND CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/297,167, filed on Feb. 19, 2016, the entirety of
which is incorporated by reference herein.
BACKGROUND
[0002] Semiconductor devices are used in a variety of electronic
applications, such as personal computers, cell phones, digital
cameras, and other electronic equipment. Semiconductor devices are
typically fabricated by sequentially depositing insulating or
dielectric layers, conductive layers, and semiconductor layers of
materials over a semiconductor substrate, and patterning the
various material layers using lithography to form circuit
components and elements thereon.
[0003] The semiconductor industry continues to improve the
integration density of various electronic components (e.g.,
transistors, diodes, resistors, capacitors, etc.) by continual
reductions in minimum feature size, which allows more components to
be integrated into a given area. These smaller electronic
components also require smaller packages that utilize less area
than the packages of the past, in some applications.
[0004] In an ion implanter, an ion generator may generate an ion
beam and direct the ion beam towards the target wafer. Ion
implantation is a process in semiconductor manufacturing for doping
different atoms or molecules into a wafer. By employing ion
implantation, the majority charge carriers of the implanted
portions of the wafer may be altered so as to produce different
types and levels of conductivity in regions of a wafer. Ion
implanters are automated tools which are used to perform the ion
implantation. In an ion implanter, an ion generator may generate an
ion beam and direct the ion beam towards the target wafer. The
target wafer should be handled properly onto the wafer holder for
the implanter to properly implant the target wafer.
[0005] Although existing devices and methods for implanting ion
implantation process have been generally adequate for their
intended purposes, they have not been entirely satisfactory in all
respects. Consequently, it would be desirable to provide a solution
for ion implantation for use in a wafer process apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Aspects of the present disclosure are best understood from
the following detailed description when read with the accompanying
figures. It should be noted that, in accordance with the standard
practice in the industry, various features are not drawn to scale.
In fact, the dimensions of the various features may be arbitrarily
increased or reduced for clarity of discussion.
[0007] FIG. 1 shows a schematic block diagram of a processing
apparatus in accordance with some embodiments.
[0008] FIG. 2 shows a schematic view of an ion beam generator, in
accordance with some embodiments.
[0009] FIG. 3 shows a schematic cross-sectional view of partial
elements of an arc chamber and an inlet port, in accordance with
some embodiments.
[0010] FIG. 4 shows a top view of a lower wall of an arc chamber,
in accordance with some embodiments.
[0011] FIG. 5 shows a top view of an intermediate plate of an arc
chamber, in accordance with some embodiments.
[0012] FIG. 6 shows a schematic view of an inlet port, in
accordance with some embodiments.
[0013] FIG. 7 shows a flow chart illustrating a method for
generating an ion beam in an ion implantation process, in
accordance with some embodiments.
[0014] FIG. 8 shows a schematic view of a lower wall covered with
an intermediate plate, schematically depicting flow patents of a
gas.
[0015] FIG. 9 shows a schematic cross-sectional view of a lower
wall covered with an intermediate plate with gas discharging
through gas outlets, schematically depicting flow patents of a
gas.
[0016] FIG. 10A shows a side view of a typical ion beam generator
with single gas outlet, schematically depicting flow patents of a
gas.
[0017] FIG. 10B shows a side view of an ion beam generator of the
disclosure, schematically depicting flow patents of a gas.
DETAILED DESCRIPTION
[0018] The following disclosure provides many different
embodiments, or examples, for implementing different features of
the subject matter provided. Specific examples of solutions and
arrangements are described below to simplify the present
disclosure. These are, of course, merely examples and are not
intended to be limiting. For example, the formation of a first
feature over or on a second feature in the description that follows
may include embodiments in which the first and second features are
formed in direct contact, and may also include embodiments in which
additional features may be formed between the first and second
features, such that the first and second features may not be in
direct contact. In addition, the present disclosure may repeat
reference numerals and/or letters in the various examples. This
repetition is for the purpose of simplicity and clarity and does
not in itself dictate a relationship between the various
embodiments and/or configurations discussed.
[0019] Furthermore, spatially relative terms, such as "beneath,"
"below," "lower," "above," "upper" and the like, may be used herein
for ease of description to describe one element or feature's
relationship to another element(s) or feature(s) as illustrated in
the figures. The spatially relative terms are intended to encompass
different orientations of the device in use or operation in
addition to the orientation depicted in the figures. The apparatus
may be otherwise oriented (rotated 90 degrees or at other
orientations) and the spatially relative descriptors used herein
may likewise be interpreted accordingly. It is understood that
additional operations can be provided before, during, and after the
method, and some of the operations described can be replaced or
eliminated for other embodiments of the method.
[0020] FIG. 1 is a schematic block diagram of a processing
apparatus 1 in accordance with some embodiments. In some
embodiments, the processing apparatus 1 is configured to perform
ion implantation on a work piece, such as a semiconductor wafer.
Additionally, the processing apparatus 1 may be configured to
perform other processing using ion beams, such as film deposition
or surface treatment. Furthermore, the processing apparatus 1 is
configured to process not only wafers for semiconductor devices,
but also other types of substrates, such as solar panels.
[0021] The processing apparatus 1 includes an ion beam generator
10, a scanning device 20, an intermediate multi-pole device 30, an
output multi-pole device 40, an end station 50, and a controller
60. The scanning device 20, the intermediate multi-pole device 30,
and the output multi-pole device 40 are arranged along a path 70
between the ion beam generator 10 and the end station 50.
[0022] The ion beam generator 10 is configured to generate an ion
beam. The ion beam generator 10 transmits the ion beam toward the
end station 50. An ion beam generator 10 in accordance with some
embodiments will be described with respect to FIGS. 2-6.
[0023] The scanning device 20 is located downstream of the ion beam
generator 10 on the path 90. The scanning device 20 is configured
to scan the ion beam having the first configuration in a scanning
direction that is transverse to the path 90. In one or more
embodiments, the scanning device 20 includes a pair of coils for
generating an electromagnetic field between the coils that varies
in time in accordance with the frequency of the power supplied to
the coils. As the ion beam passes between the pair of coils, the
time-varying electromagnetic field deflects the ions in the ion
beam according to the left-hand rule or the right-hand rule. As a
result, the whole ion beam is reciprocally deflected, i.e.,
scanned, in the scanning direction between the pair of coils.
[0024] The intermediate multi-pole device 30 is located downstream
of the scanning device 20 on the path 90. The intermediate
multi-pole device 30 is configured to control the parallelism of
the ion beam. In other words, the intermediate multi-pole device 30
is configured to adjust the trajectory of ions in the ion beam to
be parallel, or as close as possible to being parallel, with the
path 90 along which the ion beam is being transmitted. As a result,
the ion beam output from the intermediate multi-pole device 30
includes ions that travel in parallel or substantially parallel
trajectories. In one or more embodiments, the intermediate
multi-pole device 30 is omitted from the processing apparatus
1.
[0025] The output multi-pole device 40 is configured to control the
uniformity of the ion beam. In other words, the output multi-pole
device 40 is configured to adjust the beam current and/or beam
energy so that it is uniform, or as close as possible to being
uniform, across the beam profile. As a result, the ion beam output
from the output multi-pole device 40 is uniform, or substantially
uniform, across the beam profile, thereby permitting a uniform dose
of ions to be applied to a work piece. In one or more embodiments,
the output multi-pole device 40 is omitted from the processing
apparatus 1.
[0026] The end station 50 is located at the end of the path 90. The
end station 50 is configured to support a work piece thereon. In
one or more embodiments, the work piece is a semiconductor wafer.
The end station 50 includes a chuck for holding the work piece
thereon, and an actuator for moving the chuck, with the work piece
held thereon, in one or more directions. The movement of the chuck
is configured so that the ion beam impinges in a uniform manner on
the work piece. In some embodiments, the end station 50 further
includes a load lock for transferring wafers into and out of the
processing apparatus 1, and a robot arm for transferring wafers
between the chuck and the load lock. In some embodiments, the end
station 50 further includes a measuring device for measuring one or
more properties of the ion beam to be impinging on the work piece,
thereby providing feedback information for adjusting the ion beam
in accordance with a processing recipe to be applied to the work
piece. Examples of measured ion beam properties include, but are
not limited to, beam profile, beam energy and beam current.
[0027] The controller 60 is coupled to the various components of
the processing apparatus 1 for controlling operation of the various
components. For example, the controller 60 controls the ion beam
generator 10 to vary one or more ion beam properties, including,
but not limited to, beam current, beam energy and beam profile. The
controller 60 further controls parameters, e.g., the scanning
frequency, of the scanning operation of the scanning device 20. The
controller 60 also controls one or more of the parallelism tuning
operation of the intermediate multi-pole device 30 and the
uniformity tuning operation of the output multi-pole device 40. The
controller 60 is coupled to the end station 50 to control one or
more of work piece transfer and chuck movement. In one or more
embodiments, the controller 60 is coupled to the measuring device
provided in the end station 50 to receive the feedback information
for adjusting operation of one or more of the other components of
the processing apparatus 1. In some embodiments, the controller 60
is one or more computers or microprocessors programmed to perform
one or more functions described herein. In some embodiments, the
controller 60 is one or more microprocessors hard-wired to perform
one or more functions described herein.
[0028] FIG. 2 is a schematic view of an ion beam generator 10, in
accordance with some embodiments. In some embodiments, the ion beam
generator 10 includes a gas source 11, an arc chamber 12, an inlet
port 13, a filament 14, a filament power supply 15, an electrode
16, an arc power supply 17, a set of magnets 18N and 18S, and an
extraction electrode 19.
[0029] The gas source 11 is configured to store and supply working
gas to be ionized into the arc chamber 12. In some embodiments, the
gas source 11 includes a container 112, a valve 114, and a tube
116. The container 112 may contain a mixture of dopant gas and
dilutant gas (e.g., xenon and hydrogen). The dopant gas may
comprise Ge, As, B, BF.sub.3, PH.sub.3, AsH.sub.3, or other species
to be implanted in semiconductor substrates. The dilutant gas may
comprise xenon and hydrogen.
[0030] The tube 116 connects the gas source 11 to the arc chamber
12. The valve 114 connects to the tube 116 to control the flow of
the working gas in the tube 116 according to control signal from
the controller 60 (FIG. 1).
[0031] In some embodiments, the arc chamber 12 includes a lower
wall 121, a side wall 122, a top wall 123, and an intermediate
plate 124. The lower wall 121, the side wall 122, and the top wall
123 define an interior in the arc chamber 12.
[0032] In some embodiments, the filament 14 and the electrode 16
are positioned at two opposite sides of the side wall 122. The
filament power supply 15 provides power to heat the filament 14,
causing acceleration of electrons toward the filament 14. The arc
power supply 15 supplies the power to the electrode 16 to
accelerate electrons emitted by the filament 14 into a plasma. The
set of magnets 18N and 18S is provided to establish a magnetic
field for the ion beam formation. The top wall 123 has an aperture
1231, through which the ion beam passes. The extraction electrode
19 shapes and defines the ion beam as it leaves the ion beam
generator 10.
[0033] FIG. 3 shows a schematic cross-sectional view of partial
elements of the arc chamber 12 and the inlet port 13, in accordance
with some embodiments. In some embodiments, a first recess 125 is
formed on the top surface 1210 of the lower wall 121. A second
recess 126 is formed at the bottom surface 1251 of the first recess
125. The width W1 of the first recess 125 is greater than the width
W2 of the second recess 126, and a bottom surface 1251 of the first
recess 125 vertically connects the side surface 1252 to the side
wall 1262.
[0034] Additionally, a through hole 127 is formed at the
substantial center of the bottom surface 1261 of the second recess
126. The through hole 127 connects the second recess 126 to the
bottom surface 1211 and extends along a direction that is parallel
to the thickness direction of the lower wall 121.
[0035] FIG. 4 shows a top view of the lower wall 121, in accordance
with some embodiments. In some embodiments, the cross section of
the through hole 127 is not a round shape, and a straight cutting
edge 1271 is formed therein for increasing the ease and efficiency
of positioning the inlet port 13. In some embodiments, four notches
128 are formed at four corners of the first recess 125 for
facilitating the fabrication of the lower wall 121.
[0036] Referring again to FIG. 3, the intermediate plate 124 is
positioned in the first recess 125. The intermediate plate 124 may
have a shape that is compatible with that of the first recess 125.
The thickness of the intermediate plate 124 may be made equal to
the depth of the first recess 125, so that when the intermediate
plate 124 is positioned in the first recess 125, the top surface of
the intermediate plate 124 is as high as the top surface 1210 the
lower wall 121.
[0037] FIG. 5 shows a top view of the intermediate plate 124, in
accordance with some embodiments. In some embodiments, the
intermediate plate 124 has a rectangular shape including four
sides, such as two opposite long sides 1241 and 1243, and two
opposite short sides 1242 and 1244. Each of the long sides 1241 and
1243 are divided equally into four segments by three reference
points 0. Six gas outlets 129 are formed at the two long sides 1241
and 1243 of the intermediate plate 124 and arranged to correspond
to the reference points 0.
[0038] Therefore, the gas outlets 129 are arranged in first and
second groups respectively lying along two opposite long sides 1241
and 1243 of the intermediate plate 124, and the first and second
group each consists of three gas outlets spaced apart by the same
pitch. In addition, the first and the third gas outlets in each of
the first and second groups are respectively spaced apart from two
opposite short sides 1242 and 1244 of the intermediate plate 124 by
the same pitch P. The gas outlets 129 are generally symmetrically
spaced about the center of the intermediate plate 124.
[0039] In some embodiments, as shown in FIG. 5, each gas outlet 129
has an inner edge 1291, two round edges 1292, and two side edges
1293. The inner edge 1291 is parallel to the corresponding long
sides 1241 and 1243. The two side edges 1293 are vertically
connected to the corresponding long sides 1241 and 1243. The two
round edges 1292 respectively connect two ends of the inner edge
1291 to the two side edges 1293.
[0040] In some embodiments, the width W3 (width measured in a
direction that is parallel to the short sides 1242 and 1244) of
each gas outlet 129 is greater than the difference between the
width W1 and W2, so that when the intermediate plate 124 is
positioned in the first recess (FIG. 3), a portion of each gas
outlet 129 is not covered by the bottom surface 1251 of the first
recess 125. On the other hand, the width W4 (width measured in a
direction that is parallel to the long sides 1241 and 1243) ranges
from about 3.5 mm to about 6.0 mm.
[0041] Referring again to FIG. 3, the inlet port 13 is configured
to connect the gas source 11 (FIG. 2) to the arc chamber 12. In
some embodiments, the inlet port 13 is connected to the through
hole 127 of the arc chamber 12. The inlet port 13 may have a first
flow path 131 extending along the longitudinal direction of the
inlet port 13 and a second flow path 132 vertically connected to
the first flow path 131. The gas from the gas source 11 (FIG. 2) is
supplied into the second recess 126 via the inlet port 13 in the
order of the second flow path 132 and the first flow path 131.
[0042] FIG. 6 shows a schematic view of the inlet port 13, in
accordance with some embodiments of the disclosure. In some
embodiments, the inlet port 13 includes a head portion 133 formed
at one end of the inlet port 13. The inlet port 13 connects the
through hole 127 (FIG. 3) via the head portion 133. The head
portion 133 has a shape that is compatible with that of the through
hole 127.
[0043] FIG. 7 is a flow chart illustrating a method 80 for
generating an ion beam in an ion implantation process, in
accordance with some embodiments. For illustration, the flow chart
will be described in company with the schematic views shown in
FIGS. 2-6 and 8. Some of the described stages can be replaced or
eliminated in different embodiments. Additional features can be
added to the semiconductor device structure. Some of the features
described below can be replaced or eliminated in different
embodiments.
[0044] The method 80 begins with an operation 81 in which a working
gas is supplied into the first portion of the arc chamber 16. In
some embodiments, the arc chamber 16 is divided into two portions
by the intermediate plate 124. A first portion of the arc chamber
16 is underneath the intermediate plate 124 (i.e., space defined by
the intermediate plate 124 and the second recess 126), and a second
portion of the arc chamber 16 is above the intermediate plate 124
(i.e., space defined by the lower wall, side wall 1, and the top
wall). The first portion and the second portion of the arc chamber
16 communicate with each other via the gas outlets 129 formed at
the intermediate plate 124. The working gas may be applied to the
arc chamber at a pressure from about 1.0 Torr to about 4.0 Torr
[0045] Afterwards, the method 80 continues an operation 82 in which
the working gas is guided into the second portion of the arc
chamber 16 via the gas outlets 129 as shown in FIG. 8. In some
embodiments, the working gas passes through the gas outlets 129 at
the same flow rate, and thus the same amount of working gas is
supplied to the regions above each of the gas outlets 129. Since
the gas outlets 129 are spaced the same distance away from one
another, the working gas becomes evenly distributed in the second
portion of the arc chamber 16.
[0046] It should be noted that, as shown in FIG. 9, since each of
the gas outlets 129 is arranged to correspond to a side surface
1262 of the second recess 126, before the working gas enters the
gas outlets 129, the working gas flows along the side surface 1262.
As a result, the working gas is guided along a direction that is
perpendicular to the immediate plate 126 by the side wall 1262 of
the second recess 126. In this manner, the uniformity of the
working gas in a depth direction of the arc chamber 16 is
increased.
[0047] Afterwards, the method 80 continues an operation 83 in which
an ion beam is generated from the working gas in the second portion
of the arc chamber. In some embodiments, a radio frequency (RF) or
microwave power is supplied to the filament 14 from the filament
power supply 15 to excite free electrons within the second portion
of the arc chamber 16. The arc current applied to the filament may
be ranged from about 170 A to about 150 A. The excited electrons
collide with the gas molecules to generate ions. The generated ions
which are positively charged are extracted through the aperture
1231 by supplying a negative potential to the extraction electrode
19.
[0048] FIG. 10A shows a side view of a typical ion beam generator
with single gas outlet, depicting the flow field of a gas. FIG. 10B
shows a side view of an ion beam generator 10 of the disclosure,
depicting the flow field of a gas. Compared with the typical ion
beam generator, the gas is distributed more uniformly throughout
the entire region of in the arc chamber 16 of the disclosure,
especially the central region (i.e, the region between the filament
14 and the electrode 16 shown in FIG. 2) where the ionization
process occurs.
[0049] Table 1 provides data from two tests that were conducted
using an arc chamber with a single gas outlet and an arc chamber
with multiple gas outlets. To generate an ion beam current using
the arc chamber with a single gas outlet, the gas is supplied at a
pressure of 2.0 Torr, and an electric current applied to the
filament 14 is 2.8 A. To generate an ion beam current using the arc
chamber with multiple gas outlets, the gas is supplied at a
pressure of 1.3 Torr, and an electric current applied to the
filament 14 is 1.9 A.
TABLE-US-00001 TABLE 1 Beam S/H life current time Tune beam
parameter (uA) (days) bottom plate Gas (Torr) 2.0 450 1.2 with
single Arc current (A) 2.8 opening Source magnet (A) 30.0 bottom
plate Gas (Torr) 1.3 450 1.6 with multiple Arc current (A) 1.9
openings Source magnet (A) 15
[0050] Embodiments of a method and apparatus for generating an ion
beam for an ion implantation process are provided. Since gas to be
ionized is supplied through multiple gas outlets into an ionized
region in the arc chamber, the gas is uniformly distributed in the
arc chamber. Compared to a typical arc chamber with a single gas
outlet, the ion beam generator uses small amount of gas (35% gas
usage reduction) and less electrical current (32% arc current
reduction) to generate the same current of ion beam. As a result,
the manufacturing cost is reduced. Additionally, since a lower
electrical current is applied to the filament, the lifetime of the
filament is increased (32% source head life time improvement). A
higher throughput capability is realized since the expected and/or
actual repair/replacement times are prolonged.
[0051] In accordance with some embodiments an ion beam generator
used in a semiconductor processing system is provided. The ion beam
generator includes an arc chamber. The arc chamber includes a lower
all, a side wall, and an intermediate plate. The side wall is
connected the lower wall. A first recess is formed on the lower
wall, and a second recess is formed at a bottom surface of the
first recess, and a through hole is formed at a bottom surface of
the second recess. The intermediate plate is positioned in the
first recess and includes a plurality of gas outlets formed on two
opposite edges of the intermediate plate. The ion beam generator
further includes a gas supply. The gas supply is connected to the
through hole to supply gas into a gas reservoir defined by the
intermediate plate and the second recess. The ion beam generator
also includes a filament and an electrode. The filament and an
electrode are respectively positioned in two sides of the side wall
for generating an ion plasma.
[0052] In accordance with some embodiments an ion beam generator
used in a semiconductor processing system is provided. The ion beam
generator includes an arc chamber. The arc chamber includes a lower
all, a side wall, and an intermediate plate. The side wall is
connected the lower wall. The intermediate plate is positioned on
the lower wall and includes six gas outlets. Each of two opposite
long sides of the intermediate plate is equally divided into four
segments by three reference points, the six outlets are arranged
corresponding to the six reference points.
[0053] In accordance with some embodiments an ion beam generator
used in a method for generating ion beam in ion implantation
process is provided. The method includes sending supplying a
working gas into a first portion of an arc chamber which is
separated from a second portion of the arc chamber by an
intermediate plate. The method further includes guiding the working
gas into the second portion of the arc chamber via a plurality of
gas outlets opposite edges of the intermediate plate. The method
also includes generating an ion beam from the working gas in the
second portion of the arc chamber.
[0054] Although the embodiments and their advantages have been
described in detail, it should be understood that various changes,
substitutions, and alterations can be made herein without departing
from the spirit and scope of the embodiments as defined by the
appended claims. Moreover, the scope of the present application is
not intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods, and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure, processes, machines, manufacture, compositions of
matter, means, methods, or steps, presently existing or later to be
developed, that perform substantially the same function or achieve
substantially the same result as the corresponding embodiments
described herein may be utilized according to the disclosure.
Accordingly, the appended claims are intended to include within
their scope such processes, machines, manufacture, compositions of
matter, means, methods, or steps. In addition, each claim
constitutes a separate embodiment, and the combination of various
claims and embodiments are within the scope of the disclosure.
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