U.S. patent application number 15/291193 was filed with the patent office on 2017-04-13 for apparatus for monitoring pulsed high-frequency power and substrate processing apparatus including the same.
This patent application is currently assigned to SEMES CO., LTD.. The applicant listed for this patent is SEMES CO., LTD.. Invention is credited to Jong Hwan AN, Hong Won LEE, Shin-Woo NAM, Jae Bak SHIM.
Application Number | 20170103871 15/291193 |
Document ID | / |
Family ID | 58498930 |
Filed Date | 2017-04-13 |
United States Patent
Application |
20170103871 |
Kind Code |
A1 |
AN; Jong Hwan ; et
al. |
April 13, 2017 |
APPARATUS FOR MONITORING PULSED HIGH-FREQUENCY POWER AND SUBSTRATE
PROCESSING APPARATUS INCLUDING THE SAME
Abstract
Disclosed are an apparatus for monitoring pulsed high-frequency
power and a substrate processing apparatus including the same. The
apparatus includes an attenuation module configured to attenuate a
pulsed high-frequency power signal; a rectifier module configured
to convert the pulsed high-frequency power signal into a direct
current signal; and a detection module configured to detect a pulse
parameter based on the direct current signal.
Inventors: |
AN; Jong Hwan; (Yongin-si,
KR) ; NAM; Shin-Woo; (Yongin-si, KR) ; LEE;
Hong Won; (Yongin-si, KR) ; SHIM; Jae Bak;
(Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEMES CO., LTD. |
Cheonan-si |
|
KR |
|
|
Assignee: |
SEMES CO., LTD.
Cheonan-si
KR
|
Family ID: |
58498930 |
Appl. No.: |
15/291193 |
Filed: |
October 12, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01R 29/02 20130101;
H03H 7/24 20130101; G01R 21/12 20130101; H03H 7/38 20130101; G01R
23/10 20130101; H01J 37/32174 20130101; H01J 2237/334 20130101;
H01J 37/32146 20130101; H01J 37/32935 20130101; H02M 7/04 20130101;
G01R 23/04 20130101 |
International
Class: |
H01J 37/32 20060101
H01J037/32; G01R 29/02 20060101 G01R029/02; H03H 7/24 20060101
H03H007/24; G01R 23/10 20060101 G01R023/10; H02M 7/04 20060101
H02M007/04; H03H 7/38 20060101 H03H007/38 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 12, 2015 |
KR |
10-2015-0142288 |
Claims
1. An apparatus for monitoring pulsed high-frequency power, the
apparatus comprising: a rectifier module configured to convert a
pulsed high-frequency power signal into a direct current signal;
and a detection module configured to detect a pulse parameter based
on the direct current signal.
2. The apparatus of claim 1, further comprising an attenuation
module configured to attenuate the pulsed high-frequency power
signal, wherein the rectifier module converts a high-frequency
power signal attenuated by the attenuation module into a direct
current signal.
3. The apparatus of claim 1, wherein the pulse parameter comprises
at least one of a pulse frequency, a pulse duty ratio and a pulse
phase of the direct current signal.
4. The apparatus of claim 1, wherein the detection module
comprises: a differentiator configured to differentiate the direct
current signal; and an edge detection unit configured to detect an
edge of the direct current signal based on a differentiation value
obtained by differentiating the direct current signal through the
differentiator.
5. The apparatus of claim 4, wherein the edge detection unit
comprises: a rising edge detection unit configured to detect a
rising edge of the direct current signal; and a falling edge
detection unit configured to detect a falling edge of the direct
current signal.
6. The apparatus of claim 5, wherein the detection module further
comprises a pulse frequency calculation unit configured to
calculate a pulse frequency of the direct current signal based on
at least two continuous rising edge signals detected by the rising
edge detection unit.
7. The apparatus of claim 5, wherein the detection module further
comprises a pulse duty ratio calculation unit configured to
calculate a pulse duty ratio of the direct current signal based on
the rising and falling edge signals sequentially detected by the
rising and falling edge detection units.
8. The apparatus of claim 4, wherein the detection module further
comprises a pulse phase calculation unit configured to calculate a
phase by comparing edge signals detected by the edge detection unit
with one another when a plurality of direct current signals are
applied to the detection module.
9. The apparatus of claim 2, wherein the attenuation module
attenuates the pulsed high-frequency power signal such that the
pulsed high-frequency power signal is in a range of 0 V to 10
V.
10. An apparatus for processing a substrate, the apparatus
comprising: a high-frequency power source configured to provide at
least one high-frequency power; a pulse input unit configured to
apply an ON/OFF pulse to the high-frequency power source to pulse
the high-frequency power; a chamber comprising a plasma source
configured to generate plasma by using the pulsed high-frequency
power; an impedance matching unit connected between the
high-frequency power source and the chamber to perform impedance
matching; an attenuation module disposed on an outside of the
chamber to attenuate a pulsed high-frequency power signal which is
applied to the chamber; a rectifier module configured to convert a
high-frequency power signal attenuated by the attenuation module
into a direct current signal; and a detection module configured to
detect a pulse parameter based on the direct current signal.
11. The apparatus of claim 10, wherein the pulse parameter
comprises at least one of a pulse frequency, a pulse duty ratio and
a pulse phase of the direct current signal.
12. The apparatus of claim 10, wherein the attenuation module is
disposed between the chamber and the impedance matching unit or
between the high-frequency power source and the impedance matching
unit.
13. The apparatus of claim 10, wherein the detection module
comprises: a differentiator configured to differentiate the direct
current signal; and an edge detection unit configured to detect an
edge of the direct current signal based on a differentiation value
obtained by differentiating the direct current signal through the
differentiator.
14. The apparatus of claim 13, wherein the edge detection unit
comprises: a rising edge detection unit configured to detect a
rising edge of the direct current signal; and a falling edge
detection unit configured to detect a falling edge of the direct
current signal.
15. A method of monitoring pulsed high-frequency power, the method
comprising: differentiating a direct current signal of the pulsed
high-frequency power; detecting an edge signal of the direct
current signal of the pulsed high-frequency power based on a
differentiation value of the differentiated direct current signal;
and calculating a pulse parameter of the direct current of the
pulsed high-frequency power based on the detected edge signal.
16. The method of claim 15, wherein the detecting of the edge
signal comprises: detecting a rising edge signal of the direct
current signal of the pulsed high-frequency power; and detecting a
falling edge signal of the direct current signal of the pulsed
high-frequency power.
17. The method of claim 16, wherein the calculating of the pulse
parameter comprises calculating a pulse frequency of the direct
current signal based on at least two continuous rising edge signals
of the rising edge signals.
18. The method of claim 16, wherein the calculating of the pulse
parameter comprises calculating a pulse duty ratio of the direct
current signal based on the rising and falling edge signals
sequentially detected.
19. The method of claim 16, wherein the calculating of the pulse
parameter comprises, when the direct current signal of the pulsed
high-frequency power includes a plurality of direct current
signals, calculating a pulse phase by comparing edge signals of the
current signals with one another.
20. A computer-readable recording medium recording a program to
implement method of claim 15.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] A claim for priority under 35 U.S.C. .sctn.119 is made to
Korean Patent Application No. 10-2015-0142288 filed Oct. 12, 2015,
in the Korean Intellectual Property Office, the entire contents of
which are hereby incorporated by reference.
BACKGROUND
[0002] Embodiments of the inventive concept described herein relate
to an apparatus for monitoring pulsed high-frequency power and a
substrate processing apparatus including the same.
[0003] Devices such as component transistors are formed on a
semiconductor wafer made of silicon in semiconductor integrated
circuit (IC) manufacture. In such a manufacturing process, various
material layers are deposited to form or construct an IC circuit,
where the various material layers are connected to each other
through metallization lines.
[0004] However, in a semiconductor etching process using plasma,
since many charges are non-uniformly accumulated on the surface of
a wafer, destructive current may be generated on a part of a metal
line material or arcing may be caused in dielectric layers.
[0005] Such destructive current or arcing destroys or damages
specific devices previously formed on a wafer and in addition,
causes a processing chamber to be electrically damaged, so that a
serious loss may be caused. However, when the high-frequency power
supplied to the plasma in a plasma chamber is pulsed (by repeatedly
applying ON/OFF pulses for a specific time) to neutralize the
charges accumulated on the wafer surface for an OFF time, the
damages may be prevented.
SUMMARY
[0006] Embodiments of the inventive concept provide an apparatus
and a method for monitoring pulsed high-frequency power which can
easily monitor the pulsed high-frequency (RF) power in real
time.
[0007] Technical tasks obtainable from the inventive concept are
non-limited the above-mentioned technical task. And, other
unmentioned technical tasks may be clearly understood from the
following description by those having ordinary skill in the
technical field to which the inventive concept pertains.
[0008] According to one aspect of an embodiment, an apparatus for
monitoring pulsed high-frequency power includes a rectifier module
configured to convert a pulsed high-frequency power signal into a
direct current signal; and a detection module configured to detect
a pulse parameter based on the direct current signal.
[0009] The apparatus may further include an attenuation module
configured to attenuate the pulsed high-frequency power signal,
wherein the rectifier module converts a high-frequency power signal
attenuated by the attenuation module into a direct current
signal.
[0010] The pulse parameter may include at least one of a pulse
frequency, a pulse duty ratio and a pulse phase of the direct
current signal.
[0011] The detection module may include a differentiator configured
to differentiate the direct current signal; and an edge detection
unit configured to detect an edge of the direct current signal
based on a differentiation value obtained by differentiating the
direct current signal through the differentiator.
[0012] The edge detection unit may include a rising edge detection
unit configured to detect a rising edge of the direct current
signal; and a falling edge detection unit configured to detect a
falling edge of the direct current signal.
[0013] The detection module may further include a pulse frequency
calculation unit configured to calculate a pulse frequency of the
direct current signal based on at least two continuous rising edge
signals detected by the rising edge detection unit.
[0014] The detection module may further include a pulse duty ratio
calculation unit configured to calculate a pulse duty ratio of the
direct current signal based on the rising and falling edge signals
sequentially detected by the rising and falling edge detection
units.
[0015] The apparatus detection module may further include a pulse
phase calculation unit configured to calculate a phase by comparing
edge signals detected by the edge detection unit with one another
when a plurality of direct current signals are applied to the
detection module.
[0016] The attenuation module may attenuate the pulsed
high-frequency power signal such that the pulsed high-frequency
power signal is in a range of 0 V to 10 V.
[0017] According to another aspect of an embodiment, an apparatus
for processing a substrate includes a high-frequency power source
configured to provide at least one high-frequency power; a pulse
input unit configured to apply an ON/OFF pulse to the
high-frequency power source to pulse the high-frequency power; a
chamber comprising a plasma source configured to generate plasma by
using the pulsed high-frequency power; an impedance matching unit
connected between the high-frequency power source and the chamber
to perform impedance matching; an attenuation module disposed on an
outside of the chamber to attenuate a pulsed high-frequency power
signal which is applied to the chamber; a rectifier module
configured to convert a high-frequency power signal attenuated by
the attenuation module into a direct current signal; and a
detection module configured to detect a pulse parameter based on
the direct current signal.
[0018] The pulse parameter may include at least one of a pulse
frequency, a pulse duty ratio and a pulse phase of the direct
current signal.
[0019] The attenuation module may be disposed between the chamber
and the impedance matching unit or between the high-frequency power
source and the impedance matching unit.
[0020] The detection module may include a differentiator configured
to differentiate the direct current signal; and an edge detection
unit configured to detect an edge of the direct current signal
based on a differentiation value obtained by differentiating the
direct current signal through the differentiator.
[0021] The edge detection unit may include a rising edge detection
unit configured to detect a rising edge of the direct current
signal; and a falling edge detection unit configured to detect a
falling edge of the direct current signal.
[0022] According to still another aspect of an embodiment, a method
of monitoring pulsed high-frequency power includes differentiating
a direct current signal of the pulsed high-frequency power;
detecting an edge signal of the direct current signal of the pulsed
high-frequency power based on a differentiation value of the
differentiated direct current signal; and calculating a pulse
parameter of the direct current of the pulsed high-frequency power
based on the detected edge signal.
[0023] The detecting of the edge signal may include detecting a
rising edge signal of the direct current signal of the pulsed
high-frequency power; and detecting a falling edge signal of the
direct current signal of the pulsed high-frequency power.
[0024] The calculating of the pulse parameter may include
calculating a pulse frequency of the direct current signal based on
at least two continuous rising edge signals of the rising edge
signals.
[0025] The calculating of the pulse parameter may include
calculating a pulse duty ratio of the direct current signal based
on the rising and falling edge signals sequentially detected.
[0026] The calculating of the pulse parameter may include, when the
direct current signal of the pulsed high-frequency power includes a
plurality of direct current signals, calculating a pulse phase by
comparing edge signals of the current signals with one another.
[0027] According to still another aspect of an embodiment, a
computer-readable recording medium may record a program to
implement a method of monitoring pulsed high-frequency power.
[0028] Other aspects, advantages, and salient features of the
disclosure will become apparent to those skilled in the art from
the following detailed description, which, taken in conjunction
with the annexed drawings, discloses various embodiments of the
present disclosure.
BRIEF DESCRIPTION OF THE FIGURES
[0029] The above and other objects and features will become
apparent from the following description with reference to the
following figures, wherein like reference numerals refer to like
parts throughout the various figures unless otherwise specified,
and wherein:
[0030] FIG. 1 is a view illustrating a substrate processing
apparatus including an apparatus for monitoring pulsed
high-frequency power according to an embodiment;
[0031] FIG. 2 is a schematic view illustrating interworking between
elements of a substrate processing apparatus including an apparatus
for monitoring pulsed high-frequency power according to an
embodiment;
[0032] FIG. 3 is a block diagram illustrating an apparatus for
monitoring pulsed high-frequency power according to an
embodiment;
[0033] FIG. 4 is a waveform diagram illustrating a high-frequency
power signal attenuated by an attenuation module according to an
embodiment;
[0034] FIG. 5 is a waveform diagram illustrating a direct current
(DC) signal rectified by a rectifier module according to an
embodiment;
[0035] FIG. 6 is a view illustrating a method of calculating a
pulse parameter by a detection module according to an embodiment;
and
[0036] FIG. 7 is a flowchart illustrating a method of monitoring
pulsed high-frequency power according to an embodiment.
DETAILED DESCRIPTION
[0037] Advantages and features of embodiments of the inventive
concept, and method for achieving thereof will be apparent with
reference to the accompanying drawings and detailed description
that follows. But, it should be understood that the inventive
concept is limited to the following embodiments and may be embodied
in different ways, and that the embodiments are given to provide
complete disclosure of the inventive concept and to provide
thorough understanding of the inventive concept to those skilled in
the art, and the scope of the inventive concept is limited only by
the accompanying claims and equivalents thereof.
[0038] Even though it is not defined, all terms (including
technical or scientific terms) used herein have the same meanings
as those belonging to the inventive concept is generally accepted
by common techniques in the art. The terms defined in general
dictionaries may be construed as having the same meanings as those
used in the related art and/or a text of the present application
and even when some terms are not clearly defined, they should not
be construed as being conceptual or excessively formal. The terms
used in the present specification are provided to describe
embodiments, not intended to limit it.
[0039] The terms of a singular form may include plural forms unless
referred to the contrary. The meaning of "comprises" and/or
"comprising" specifies a property, a region, a fixed number, a
step, a process, an element and/or a component but does not exclude
other properties, regions, fixed numbers, steps, processes,
elements and/or components. In addition, the terms "provided",
"having" and the like may be interpreted like the above.
[0040] Embodiments relate to an apparatus for monitoring pulsed
high-frequency power and a substrate processing apparatus including
the same, and provide an apparatus and a method which can easily
monitor pulsed high-frequency power in real time. An apparatus for
monitoring high-frequency power according to an embodiment may
rectify a pulsed high-frequency power signal applied from a
high-frequency power source to generate a direct current signal,
and detect a pulse parameter, such as a pulse frequency, a pulse
duty ratio or a pulse phase, based on the direct current signal,
such that the apparatus monitors the pulsed high-frequency power
signal. In addition, the high-frequency power signal, which is
converted into the direct current signal, may be an attenuated
high-frequency power signal in a predetermined range.
[0041] FIG. 1 is a view illustrating a substrate processing
apparatus including an apparatus for monitoring pulsed
high-frequency power according to an embodiment.
[0042] FIG. 1 shows a substrate processing apparatus of a
capacitively coupled plasma (CCP) type, but the embodiment is not
limited thereto. The embodiment may be applied to a substrate
processing apparatus of an inductively coupled plasma (ICP)
type.
[0043] Referring to FIG. 1, the substrate processing apparatus 10
processes a substrate W by using plasma. For example, the substrate
processing apparatus 10 may perform a process of etching the
substrate W. The substrate processing apparatus 10 may include a
chamber 100, a substrate support assembly 200, a gas supply unit
300, a plasma generation unit 400, an attenuation module 1100, a
pulse input unit 700 and an apparatus 1000 for monitoring pulsed
high-frequency power.
[0044] The chamber 100 has a space 101 therein. The inner space 101
serves as a space in which performs a process of treating the
substrate W with plasma. An exhaust hole 102 is formed on a bottom
surface of the chamber 100. The exhaust hole 102 is connected to an
exhaust line 121. Reaction by-products produced during a process
and gas residual in the chamber 100 may be exhausted through the
exhaust line 121. The inner space 101 of the chamber 100 is
decompressed by an exhausting process.
[0045] The substrate support assembly 200 is placed at an inside of
the chamber 100. The substrate support assembly 200 supports the
substrate W. The substrate support assembly 200 includes an
electrostatic chuck for holding the substrate W by using
electrostatic force. The substrate support assembly 200 includes a
dielectric plate 210, a first electrode 220, a heater 230, a lower
electrode 240 and an insulating plate 270.
[0046] The dielectric plate 210 is disposed on an upper end part of
the substrate support assembly 200. The dielectric plate 210 is
formed of a disc-shaped dielectric member. The substrate W is
placed on the dielectric plate 210. Since a top surface of the
dielectric plate 210 has a radius less than that of the substrate
W, an edge area of the substrate W is placed outside the dielectric
plate 210. A first supply passage 211 is formed in the dielectric
plate 210. The first supply passage 211 extends from the top
surface to the bottom surface of the dielectric plate 210. The
first supply passage 211 includes a plurality of first supply
passages 211 which are spaced apart from each other and serves as a
passage through which a heat transfer medium is supplied to the
bottom surface of the substrate W.
[0047] The first electrode 220 and the heater 230 are embedded in
the dielectric plate 210. The first electrode 220 is placed over
the heater 230. The first electrode 220 may be electrically
connected to a first power source 220a. The first power source 220a
may include a direct current power source. A switch 220b may be
installed between the first electrode 220 and the first power
source 220a. The first electrode 220 may be electrically connected
to the first power source 220a through an ON/OFF operation of the
switch 220b. When the first switch 220b is switched on, a direct
current may be applied to the first electrode 220. Electrostatic
force operates between the first electrode 220 and the substrate W
due to the current applied to the first electrode 220, so that the
substrate W may be attached to the dielectric plate 210 due to the
electrostatic force.
[0048] A lower power supply unit 221 applies high-frequency power
to the lower electrode 240. The lower power supply unit 221
includes a lower RF power supply 222 and 223 and a lower impedance
matching unit 225. The lower RF power source 222 and 223 may
include plural lower RF power sources 222 and 23 as shown in FIG.
1. Alternatively, the lower RF power source 222 and 223 may include
a single RF power source. The lower RF power source 222 and 223 may
control plasma density. The lower RF power source 222 and 223 may
control ion bombardment energy. Each of the lower RF power sources
222 and 223 may generate a frequency power in the range of 2 MHz to
13.56 Hz. The lower impedance matching unit 225 is electrically
connected to the lower RF power source 222 and 223. The lower
impedance matching unit 225 allows mutually different frequency
powers to be matched with each other and applies the matched
frequency powers to the lower electrode 240.
[0049] The heater 230 is electrically connected to an external
power source (not shown). The heater 230 generates heat based on
the current applied from the external power source thereto. The
generated heat is transferred to the substrate W through the
dielectric plate 210. The substrate W is maintained at a
predetermined temperature due to the heat generated by the heater
230. The heater 230 includes a spiral-shaped coil. The heater 230
may be embedded in the dielectric plate 210 by a uniform
interval.
[0050] The lower electrode 240 is placed below the dielectric plate
210. The bottom surface of the dielectric plate 210 and the top
surface of the lower electrode 240 may adhere to each other with
adhesive 236. The lower electrode 240 may be formed of an aluminum
material. A central area of the top surface of the lower electrode
240 may be placed at a position higher than that of an edge area of
the top surface, so that a step difference is generated between the
central area and the edge area. The central area of the top surface
of the lower electrode 240 has an area corresponding that of the
bottom surface of the dielectric plate 210 and is attached to the
bottom surface of the dielectric plate 210. The lower electrode 240
includes first and second circulation passages 241 and 242 and a
second supply passage 243.
[0051] The first circulation passage 241 serves as a passage
through which the heat transfer medium is circulated. The first
circulation passage 241 may be formed in a spiral shape in the
lower electrode 240. In addition, the first circulation passage 241
may include ring-shaped passages which have mutually different
radii and are concentrically disposed. The first circulation
passages 241 may communicate with each other. The first circulation
passages 241 have the same height.
[0052] The second circulation passage 242 serves as a passage
through which coolant is circulated. The second circulation passage
242 may be formed in spiral shape in the lower electrode 240. In
addition, the second circulation passage 242 may include
ring-shaped passages which have mutually different radii and are
concentrically disposed. The second circulation passages 242 may
communicate with each other. The second circulation passage 242 may
have an area larger than the first circulation passage 241. The
second circulation passages 242 have the same height. The second
circulation passage 242 may be placed under the first circulation
passage 241.
[0053] The second supply passage 243 extends upwardly from the
first circulation passage 241 to the top surface of the lower
electrode 240. The number of second supply passages 243 corresponds
to that of the first supply passage 211. The second supply passage
243 connects the first circulation passage 241 and the first supply
passage 211 to each other.
[0054] The first circulation passage 241 is connected to a heat
transfer medium storage unit 252 through a heat transfer medium
supply line 251. The heat transfer medium storage unit 252 stores a
heat transfer medium. The heat transfer medium includes inert gas.
According to an embodiment, the heat transfer medium includes
helium gas. The helium gas is supplied to the first circulation
passage 241 through the heat transfer medium supply line 251 and
then, is supplied to the bottom surface of the substrate W via the
second supply passage 243 and the first supply passage 211 in
sequence. The helium gas serves as the medium of transferring the
heat transferred from the plasm to the substrate W to the substrate
support assembly 200. The ion particles contained in plasma are
transferred to the substrate support assembly 200 due to the
electric force formed in the substrate support assembly 200 and
collide with the substrate W while being transferred, so that an
etching process is performed. When the ion particles collide with
the substrate W, heat is generated from the substrate W. The heat
generated from the substrate W is transferred to the substrate
support assembly 200 by the helium gas supplied to the space
between the bottom surface of the substrate W and the top surface
of the dielectric plate 210. Thus, the substrate W may be
maintained at a set temperature.
[0055] The second circulation passage 242 is connected to a coolant
storage unit 262 through a coolant supply line 261. The coolant
storage unit 262 stores coolant. A cooler 263 may be provided in
the coolant storage unit 262. The cooler 263 cools the coolant to a
predetermined temperature. To the contrary, the cooler 263 may be
installed on the coolant supply line 261. The coolant supplied to
the second circulation passage 242 through the coolant supply line
261 is circulated through the second circulation passage 242 to
cool the lower electrode 240. While the lower electrode 240 is
cooled, the substrate W is cooled together with the dielectric
plate 210, so that the substrate W is maintained at a predetermined
temperature.
[0056] The insulating plate 270 is provided below the lower
electrode 240. The insulating plate 270 has a size corresponding to
the lower electrode 240. The insulating plate 270 is placed between
the lower electrode 240 and the bottom surface of the chamber 100.
The insulating plate 270 is formed of an insulating material such
that the lower electrode 240 is electrically insulated against the
chamber 100.
[0057] A focus ring 280 is disposed on an edge are of the substrate
support assembly 200. The focus ring 200 has a ring shape and
disposed around the dielectric plate 210. A top surface of the
focus ring 280 includes outer and inner parts 280a and 280b, where
the outer part 280a is higher than the inner part 280b, so that a
step difference is formed on the top surface of the focus ring 280.
The inner part 280b of the top surface of the focus ring 280 is
positioned at the same height as that of the top surface of the
dielectric plate 210. The inner part 280b of the top surface of the
focus ring 280 supports an edge area of the substrate W placed at
an outside of the dielectric plate 210. The outer part 280a of the
top surface of the focus ring 280 surrounds an edge area of the
substrate W. The focus ring 280 expands an electric field forming
area such that the substrate W is located at the center of an area
in which plasma is formed. Thus, the plasma is uniformly formed in
the entire area of the substrate W, so that each area of the
substrate W may be uniformly etched.
[0058] The gas supply unit 300 supplies process gas to the chamber
100. The gas supply unit 300 includes a gas storage unit 310, a gas
supply line 320 and a gas inflow port 330. The gas supply line 320
is connected to the gas storage unit 310 and the gas inflow port
330 and supplies the gas stored in the gas storage unit 310 to the
gas inflow port 330. The gas inflow port 330 is connected to gas
supply holes 412 formed on an upper electrode 410.
[0059] The plasma generation unit 400 excites the process gas
remaining in the chamber 100. The plasma generation unit 400
includes the upper electrode 410, a distribution plate 420 and an
upper power supply unit 440.
[0060] The upper electrode 410 has a disc shape and is placed above
the substrate support assembly 200. The upper electrode 410
includes an upper plate 410a and a lower plate 410b. The upper
plate 410a has a disc shape. The upper plate 410a is electrically
connected to an upper RF power source 441. A first RF power
generated from the upper RF power source 441 is applied to the
process gas remaining in the chamber 100 through the upper plate
410a, such that the process gas is excited. The process gas is
excited into a plasma state. A lower surface of the upper plate
410a includes a central area and an edge area, where the central
area is placed higher than the edge area so that a step difference
is generated between them. Gas supply holes 412 are formed on a
central area of the upper plate 410a. The gas supply holes 412 are
connected to the gas inflow port 330, through which gas is supplied
to a buffer space 414. A cooling passage 411 may be formed in the
upper plate 410a. The cooling passage 411 may be formed in a spiral
shape. In addition, the cooling passage 411 may include ring-shaped
passages which have mutually different radii and are concentrically
disposed. The cooling passage 411 is connected to the coolant
storage unit 432 through the coolant supply line 431. The coolant
storage unit 432 stores coolant. The coolant stored in the coolant
storage unit 432 is supplied to the cooling passage 411 through the
coolant supply line 431. The coolant is circulated through the
cooling passage 411 to cool the upper plate 410a.
[0061] The lower plate 410b is placed below the upper plate 410a.
The lower plate 410b has a size corresponding to the upper plate
410a and faces the upper plate 410a. An upper surface of the lower
plate 410b includes a central area and an edge area, where the
central area is placed lower than the edge area so that a step
difference is generated between them. The upper surface of the
lower plate 410b and the lower surface of the upper plate 410a are
combined with each other to form the buffer space 414. The buffer
space 414 serves as a space in which the gas supplied through the
gas supply holes 412 temporarily remains before the gas is supplied
to the chamber 100. Gas supply holes 413 are formed on the central
area of the lower plate 410b. The gas supply holes 413 are spaced
apart from each other by a predetermined interval. The gas supply
holes 413 are connected to the buffer space 414.
[0062] The distribution plate 420 is placed below the lower plate
410b. The distribution plate 420 has a disc shape. Distribution
holes 421 are formed on the distribution plate 420. The
distribution holes 421 are formed from the upper surface of the
distribution plate 420 to the lower surface of the distribution
plate 420. The number of the distribution holes 421 corresponds to
that of the gas supply holes 413 and the distribution holes 421 are
located corresponding to the gas supply holes 413. The process gas
remaining in the buffer space 414 is uniformly supplied to the
chamber 100 through the gas supply holes 413 and the distribution
holes 421.
[0063] The upper power supply unit 440 applies high-frequency (RF)
power to the upper plate 410a. The upper power supply unit 440 may
include an upper RF power source 441 and an upper impedance
matching unit 442. The upper RF power source 441 may generate
frequency power of 100 MHz.
[0064] The pulse input unit 7 may apply an ON/OFF pulse to the
power supply units 221 and 440. The pulsed high-frequency power may
be generated from the upper and lower RF power sources 441, 222 and
223 according to the ON/OFF pulse applied by the pulse input unit
700.
[0065] The attenuation module 1100 may attenuate the pulsed
high-frequency power signals generated from the power supply units
221 and 440. As shown, in order to sense the pulsed RF power
signals having mutually different frequencies, which are applied
from the RF power sources 222, 223, and 441, the attenuation module
1110 may include first to third attenuation modules 1110, 1130 and
1150 corresponding to the RF power sources, respectively. As one
example, the attenuation modules may be disposed between the RF
power sources and the impedance matching units, respectively, but
the embodiment is not limited thereto. The attenuation modules may
be disposed between the impedance matching units 225 and 442 and
the chamber 100, respectively.
[0066] The monitoring apparatus 1000 may detect a pulse parameter
by using the pulsed high-frequency power signal applied from the RF
power source 222, 223 and 441 to the chamber 100 to monitor the
pulsed high-frequency power. Hereinafter, the apparatus for
monitoring pulsed high-frequency power will be described in detail
with reference to FIG. 3.
[0067] FIG. 2 is a schematic view illustrating interworking between
elements of a substrate processing apparatus including an apparatus
for monitoring pulsed high-frequency power according to an
embodiment.
[0068] An apparatus for processing a substrate according to an
embodiment may include a high-frequency (RF) power source 222, 223
and 441 configured to provide at least one high-frequency power, a
pulse input unit 700 configured to apply an ON/OFF pulse to the
high-frequency power source to pulse the high-frequency power, a
chamber 100 including a plasma source configured to generate plasma
by using the pulsed high-frequency power, an impedance matching
unit 442 and 225 connected between the high-frequency power source
and the chamber 100 to perform impedance matching, an attenuation
module 1100 disposed on the outside of the chamber to attenuate a
pulsed high-frequency power signal which is applied to the chamber,
a rectifier module 1300 configured to convert a high-frequency
power signal attenuated by the attenuation module 1100 into a
direct current signal, and a detection module 1500 configured to
detect a pulse parameter from the direct current signal.
[0069] As shown in FIG. 2, the pulse input unit 700 may apply the
ON/OFF pulse to the upper and lower RF power sources 222 and 223.
Thus, the upper and lower RF power sources 222 and 223 generate
pulsed high-frequency power. The attenuation module 1100 may
attenuate the pulsed high-frequency power signal generated from
each RF power source and may transfer the attenuated high-frequency
power signal to the rectifier module 1300 of the monitoring
apparatus 1000. The rectifier module 1300 converts the received
high-frequency power signal into a direct current signal. The
detection module 1500 may detect the pulse parameter from the
direct current signal such that the pulsed high-frequency power
signal is easily monitored. For example, the pulse parameter may
include at least one among the pulse frequency, the pulse duty
ratio and the pulse phase.
[0070] FIG. 3 is a block diagram illustrating an apparatus 1000 for
monitoring pulsed high-frequency power according to an
embodiment.
[0071] As shown in FIG. 3, an apparatus 1000 for monitoring pulsed
high-frequency power according to an embodiment may include an
attenuation module 1100, a rectifier module 1300 and a detection
module 1500.
[0072] The attenuation module 1100 may attenuate the pulsed
high-frequency power signal applied form a power source and
transfer it to the rectifier module 1300. For example, the
attenuation module 1100 may include a waveguide attenuator which
senses the pulsed high-frequency power signal applied from the
power source, attenuates the sensed signal, and transfers it to a
rectifier module, but the embodiment is not limited thereto. As one
example, the high-frequency power signal may be attenuated to be in
the range of 0 V to 10 V.
[0073] The rectifier module 1300 may convert the high-frequency
power signal attenuated by the attenuation module 1100 into the
direct current signal. That is, the direct current signal may
generated by rectifying the attenuated high-frequency power signal
which is an AC signal.
[0074] The detection module 1500 may detect the pulse parameter
from the direct current signal obtained through the rectifier
module 1300. For example, the detection module may include
differentiator 1510 configured to differentiate the direct current
signal, an edge detection unit 1530 configured to detect an edge of
the direct current signal based on a differentiation value obtained
by differentiating the direct current signal through the
differentiator 1510, and a pulse parameter calculation unit 1550
configured to calculate a pulse parameter based on the detected
edge signal detected by the edge detection unit 1530, wherein the
pulse parameter includes at least one of a pulse frequency, a pulse
duty ratio and a pulse phase.
[0075] The differentiator 1510 may include a differentiation
circuit in which a capacitor and a resistor are connected in series
to each other and a voltage of the resistor is output as the output
signal, but the embodiment is not limited thereto. As one
embodiment, an arbitrary positive value of the pulse-type direct
current signal when the pulse-type direct current signal is changed
from an OFF region to an ON region and an arbitrary negative value
of the pulse-type direct current signal when the pulse-type direct
current signal is changed from an OFF region to an ON region may be
output as the output signal output by the differentiator, where the
OFF and ON regions constitute a period of the pulse-type direct
current signal.
[0076] The edge detection unit 1530 may detect an edge of the
direct current signal based on the differentiation value output
from the differentiator 1510. As one embodiment, the edge detection
unit may include a rising edge detection unit 1532 configured to
detect a rising edge of the direct current signal, and a falling
edge detection unit 1534 configured to detect a falling edge of the
direct current signal. As one embodiment, the rising edge detection
unit 1532 may detect an arbitrary positive value output from the
differentiator 1510 and the falling edge detection unit 1534 may
detect an arbitrary negative value output from the differentiator
1510.
[0077] The pulse parameter calculation unit 1550 may include a
pulse frequency calculation unit 1552 configured to calculate a
pulse frequency of the direct current signal, a pulse duty ratio
calculation unit 1554 configured to confirm a ratio of an ON time
of the direct current signal, and a pulse phase calculation unit
1556.
[0078] The pulse frequency calculation unit 1552 may calculate the
pulse frequency of the direction current signal based on at least
two continuous rising edge signals detected by the rising edge
detection unit 1532. Alternatively, the pulse frequency calculation
unit 1552 may calculate the pulse frequency of the direction
current signal based on at least two continuous falling edge
signals detected by the falling edge detection unit 1534. As one
embodiment, the rising edge signal may be an arbitrary positive
value detected by the rising edge detection unit. For example, the
pulse frequency may be calculated based on a period of arbitrary
positive values sequentially detected by the rising edge detection
unit.
[0079] The pulse duty ratio calculation unit 1554 may calculate a
pulse duty ratio of the direct current signal based on the rising
and falling edge signals sequentially detected by the rising and
falling edge detection units 1532 and 1534. As one embodiment, the
arbitrary positive and negative values may be sequentially detected
by the rising and falling edge detection units 1532 and 1534 to
calculate the pulse duty ratio of the direct current signal based
on the difference between the time points at which the positive and
negative values are detected.
[0080] When the direct current signals are applied to the detection
module, the pulse phase calculation unit 1556 may calculate the
phase by comparing the detected edge signals by the edge detection
unit 1530 with each other. As one embodiment, as shown in FIGS. 1
and 2, when the high-frequency powers having mutually different
frequencies are applied, the detection module including a storage
unit may store edge signals of the high-frequency power having
mutually different frequencies. Thus, a phase of each signal may be
calculated by setting an arbitrary reference phase for signals
having mutually different frequencies and comparing the edge
signals of high-frequency power with each other.
[0081] FIG. 4 is a waveform diagram illustrating a high-frequency
power signal attenuated by an attenuation module 1100 according to
an embodiment.
[0082] As shown in FIG. 4, the attenuation module 1100 according to
an embodiment may attenuate a pulsed high-frequency power signal PS
having an ON/OFF region to generate an attenuation signal AS in a
narrower voltage range. As one embodiment, the voltage range may
include a range of 0 V to 10 V, but the embodiment is not limited
thereto.
[0083] FIG. 5 is a waveform diagram illustrating a direct current
signal DS rectified by the rectifier module 1300 according to an
embodiment.
[0084] As shown in FIG. 5, the rectifier module 1300 according to
an embodiment may convert the attenuation signal AS of FIG. 4 into
a direct current signal DS. Thus, the direct current signal DS may
become a pulse type direct current having ON and OFF regions
constituting the period thereof.
[0085] FIG. 6 is a view illustrating a method of calculating a
pulse parameter by the detection module 1500 according to an
embodiment.
[0086] As shown in FIG. 6, the detection module 1500 according to
an embodiment may detect an edge signal based on a differentiation
value DV obtained by differentiating the direct current signal DS
from the rectifier module 1300. As shown in FIG. 6, a positive
value is output at the rising edge RE1 of the pulse of the direct
current signal DS and a negative value is output at the falling
edge FE1 of the pulse of the direct current signal DS.
[0087] Thus, to calculate the pulse frequency PF of the direct
current signal, a difference between continuous rising edge
signals, for example, the time points of rising edges 1 and 2 RE1
and RE2 may be used.
[0088] In addition, when a pulse duty ratio OD of the direct
current signal, that is, a ratio of the ON region in the direct
current signal is calculated, a time (FE1-RE1) of the ON region may
be obtained by calculating a difference between sequentially
detected rising and falling edge signals, for example, the time
points of rising edge 1 RE1 and a falling edge 1 FE1 such that the
pulse duty ratio is calculated by (FE1-RE1)/(RE2-RE1).
[0089] In addition, when a plurality of direct current signals are
applied to the detection module and a phase reference signal is
set, the phase of each direct current may be calculated by
comparing the rising or falling edge signal RE1 or FE1
corresponding to the current signal with the phase reference
signal.
[0090] FIG. 7 is a flowchart illustrating a method S1000 of
monitoring pulsed high-frequency power according to an
embodiment.
[0091] As shown in FIG. 7, a method of monitoring pulsed
high-frequency power according to an embodiment may include
differentiating a direct current signal of the pulsed
high-frequency power (S1100), detecting an edge signal of the
direct current signal of the pulsed high-frequency power based on a
differentiation value of the differentiated direct current signal
(S1200), and calculating a pulse parameter of the direct current of
the pulsed high-frequency power based on the detected edge signal
(S1300).
[0092] The detecting (S1200) may include detecting a rising edge
signal of the direct current signal of the pulsed high-frequency
power based on the differentiation value of the direct current
signal, and detecting a falling edge signal of the direct current
signal of the pulsed high-frequency power. As one embodiment, the
detecting of the rising edge signal may include detecting an
arbitrary positive value of the differentiation value of the direct
current signal, and the detecting of the falling edge signal may
include detecting an arbitrary negative value of the
differentiation value of the direct current signal.
[0093] The calculating (S1300) may include calculating a pulse
frequency of the direct current signal based on at least two
continuous rising edge signals of the rising edge signals;
calculating a pulse duty ratio of the direct current signal based
on the rising and falling edge signals sequentially detected; and,
when the direct current signal of the pulsed high-frequency power
includes a plurality of direct current signals, calculating a pulse
phase by comparing edge signals of the current signals with one
another.
[0094] The method for monitoring pulsed high-frequency power
described above may be implemented in a program executable through
a computer as an application and may be recorded on a
computer-readable recording medium. The computer-readable recording
medium may include a volatile memory such as a static RAM (SRAM), a
dynamic RAM (DRAM), a synchronous DRAM (SDRAM), etc., a
non-volatile memory such as a read only memory (ROM), a
programmable ROM (PROM), an electrically erasable and programmable
ROM (EPROM), an electrically erasable and programmable ROM
(EEPROM), a flash memory, a phase-change RAM (PRAM), a magnetic RAM
(MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), etc., a
floppy disk, a hard disk, or an optical recording media such as a
storage medium including a compact disc read only memory
(CD-ROM),), a digital versatile disc (DVD), etc., but the
embodiment is not limited thereto.
[0095] According to the inventive concept, the pulsed
high-frequency power signal can be easily monitored in real
time.
[0096] While the inventive concept has been described with
reference to exemplary embodiments, it will be apparent to those
skilled in the art that various changes and modifications may be
made without departing from the spirit and scope of the inventive
concept. Therefore, it should be understood that the above
embodiments are not limiting, but illustrative.
* * * * *