U.S. patent application number 10/233440 was filed with the patent office on 2003-03-13 for apparatus and method for surface treatment to substrate.
Invention is credited to Nishida, Kazuto, Suzuki, Naoki, Tomita, Kazuyuki.
Application Number | 20030049937 10/233440 |
Document ID | / |
Family ID | 19094732 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030049937 |
Kind Code |
A1 |
Suzuki, Naoki ; et
al. |
March 13, 2003 |
Apparatus and method for surface treatment to substrate
Abstract
The present invention provides an apparatus and a method for
surface treatment to substrates whereby the quality of substrates
can be maintained by preventing an excessive plasma treatment to
substrates. In carrying out the plasma treatment to a surface of
the substrate in a reaction chamber, there are provided an emission
spectroscopic analysis device or a mass analyzer, and a controller,
so that an energy of ions in plasma is controlled to decrease when,
e.g., bromine included in the substrate is detected, and the
surface treatment to the substrate is controlled to stop when
removing impurities of the substrate is detected to end. The
bromine once separated from the substrate is prevented from
adhering again to the substrate to corrode the substrate. Moreover,
ions are prevented from being excessively irradiated to the
substrate when the removal of impurities ends, thereby reducing
damages to the substrate. The substrate quality is maintained
accordingly.
Inventors: |
Suzuki, Naoki;
(Neyagawa-shi, JP) ; Nishida, Kazuto; (Katano-shi,
JP) ; Tomita, Kazuyuki; (Ikoma-shi, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
19094732 |
Appl. No.: |
10/233440 |
Filed: |
September 4, 2002 |
Current U.S.
Class: |
438/714 ;
438/710 |
Current CPC
Class: |
H05K 2203/095 20130101;
H01J 37/32935 20130101; H05K 3/26 20130101; H01J 37/32009 20130101;
H05K 3/323 20130101; H01J 37/3299 20130101 |
Class at
Publication: |
438/714 ;
438/710 |
International
Class: |
H01L 021/302; H01L
021/461 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2001 |
JP |
2001-268801 |
Claims
What is claimed is:
1. A substrate surface treatment apparatus for executing surface
treatment to a substrate arranged in a reaction chamber by ions in
plasma generated in the reaction chamber, which comprises: a
detecting device arranged to the reaction chamber for detecting at
least either whether or not components constituting the substrate
are separated from the substrate, or whether or not impurities
adhering to a surface of the substrate are removed by the surface
treatment; and a controller connected to the detecting device for
controlling to reduce an energy of the ions in the plasma on a
basis of the detected information by the detecting device when the
separation of components is brought about, and for controlling to
terminate the surface treatment on a basis of the detected
information by the detecting device when the removal of impurities
ends.
2. The substrate surface treatment apparatus according to claim 1,
further comprising a plasma generating device including electrodes
arranged in the reaction chamber for generating the plasma and a
power supply unit for supplying electricity to the electrodes, and
a vacuum degree adjusting device connected to the reaction chamber
for adjusting a degree of vacuum in the reaction chamber, wherein
the controller controls operations of the power supply unit and the
vacuum degree adjusting device on the basis of the detected
information by the detecting device so as to control to reduce the
energy of the ions and to end the surface treatment.
3. The substrate surface treatment apparatus according to claim 1,
wherein the detecting device is comprised of a spectroscopic
analyzer for conducting spectral observation of light generated by
the plasma and detecting the components and the impurities of the
substrate on a basis of the observation.
4. The substrate surface treatment apparatus according to claim 2,
wherein the detecting device is comprised of a spectroscopic
analyzer for conducting spectral observation of light generated by
the plasma and detecting the components and the impurities of the
substrate on a basis of the observation.
5. The substrate surface treatment apparatus according to claim 1,
wherein the detecting device is comprised of a mass analyzer for
analyzing gas elements in the reaction chamber and detecting the
components and the impurities of the substrate on a basis of the
gas analysis.
6. The substrate surface treatment apparatus according to claim 2,
wherein the detecting device is comprised of a mass analyzer for
analyzing gas elements in the reaction chamber and detecting the
components and the impurities of the substrate on a basis of the
gas analysis.
7. The substrate surface treatment apparatus according to claim 1,
wherein the components of the substrate to be detected by the
detecting device is bromine.
8. The substrate surface treatment apparatus according to claim 2,
wherein the components of the substrate to be detected by the
detecting device is bromine.
9. The substrate surface treatment apparatus according to claim 3,
wherein the components of the substrate to be detected by the
detecting device is bromine.
10. The substrate surface treatment apparatus according to claim 5,
wherein the components of the substrate to be detected by the
detecting device is bromine.
11. The substrate surface treatment apparatus according to claim 1,
wherein the impurities to be detected by the detecting device is
chlorine.
12. The substrate surface treatment apparatus according to claim 2,
wherein the impurities to be detected by the detecting device is
chlorine.
13. The substrate surface treatment apparatus according to claim 3,
wherein the impurities to be detected by the detecting device is
chlorine.
14. The substrate surface treatment apparatus according to claim 5,
wherein the impurities to be detected by the detecting device is
chlorine.
15. A substrate surface treatment method for executing surface
treatment to a substrate arranged in a reaction chamber by ions in
plasma generated in the reaction chamber, which comprises:
detecting at least either whether or not components constituting
the substrate are separated from the substrate by the surface
treatment, or whether or not impurities adhering to a surface of
the substrate are removed by the surface treatment; and controlling
on a basis of the detected information an energy of the ions in the
plasma to reduce when the separation of components is detected to
take place and the surface treatment to end when the removal of
impurities is detected to end.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an apparatus for executing
surface treatment such as cleaning, modifying or the like to
substrate surfaces by plasma, and a method for substrate surface
treatment carried out by the substrate surface treatment
apparatus.
[0002] High-packaging density has been required in the field of a
mounting technique in accordance with miniaturization and
multifunction of electronic devices. Consequently, connection
between elements and substrates should be carried out on a
remarkably fine scale, and mounting with a higher reliability is
being required. There is a method of modifying substrate surfaces
by plasma, i.e., plasma treatment as one example for securing the
reliability. For instance, the plasma treatment can remove an
organic contaminant adhering to the substrate surface, and the
bonding strength between a gold electrode and a wire in the case of
wire bonding can be improved when an inorganic substance such as
nickel hydroxide or the like deposited on an electrode face as a
bonding face formed of copper, nickel, and gold on a printed board
is removed by the sputtering action of argon plasma. Also in the
case where an IC is to be bonded to a lead electrode on a polyimide
film substrate via an ACF (anisotropic conductive film), the
bonding strength between the polyimide film and the ACF can be
improved through activation of a surface of the polyimide film
substrate by irradiating oxygen plasma to the film before bonding.
Moreover, the plasma treatment carried out to the substrate
improves the fluidity of a sealing resin on the substrate and the
adhesion between the substrate and the sealing resin.
[0003] An example of the plasma treatment method referred to above
will be described below with reference to drawings.
[0004] FIG. 3 roughly shows the configuration of a conventional
apparatus 20 for surface treatment to mounting substrates, in which
a reaction chamber 1 being grounded is provided with a gas
introduction port 2 and a vacuum exhaust port 3. A RF electrode 5
is arranged in the reaction chamber 1 via an insulating ring 4 to a
side wall of the reaction chamber 1. The RF electrode 5 has a
constitution on which a mounting substrate 6 can be placed. An
opposed electrode 7 is arranged in the reaction chamber 1, which is
arranged with facing to the RF electrode 5 and is grounded. A
RF(Radio-Frequency) is applied to the RF electrode 5 by a RF supply
source 8 through a matching tuner (not shown) and a RF power supply
part. O rings (not shown) are interposed between the RF electrode 5
and the insulating ring 4 and between the insulating ring 4 and the
side wall of the reaction chamber 1. For preventing the O rings
from being heated to 200.degree. C. or higher and maintaining the
reaction chamber 1 in vacuum, a cooling groove 9 where a cooling
water flows is formed in the side wall of the reaction chamber
1.
[0005] The surface treatment method to mounting substrates carried
out by the above-constituted surface treatment apparatus 20 will be
depicted hereinbelow in an example in which an argon gas is used to
substrates before wire bonded.
[0006] The substrate 6 before subjected to wire bonding is placed
on the RF electrode 5. While a degree of vacuum in the reaction
chamber 1 is kept to be 30 Pa with 50 SCCM(standard cc/min) of the
argon gas being supplied from the gas introduction port 2, a
RF(Radio-Frequency) of 200 W is applied to the RF electrode 5,
thereby generating plasma. Argon ions in the plasma are irradiated
onto a face of the substrate 6 exposed in the plasma. The substrate
6 is formed of glass cloth epoxy resin. An electrode 10 formed on
the surface of the substrate 6 is constituted of three layers of a
copper layer 11 having a film thickness of 35 .mu.m, a nickel layer
12 having a film thickness of 3 .mu.m and a gold layer 13 having a
film thickness of 0.05 .mu.m as shown in FIG. 4. The undercoat
nickel 12 is moved onto a surface of the gold 13 through a heat
process or the like, whereby nickel hydroxide or the like is
deposited. The nickel hydroxide is sputtered and removed by the
irradiation of argon ions. The surface of the gold 13 is cleaned
accordingly.
[0007] FIG. 5 is a schematic diagram of a case in which a silicon
chip IC 16 is bonded via an ACF (anisotropic conductive film) 15 to
a polyimide film substrate 14. As shown in FIG. 5, electrodes 18 of
the IC 16 are bonded via the ACF 15 composed of a resin containing
conductive particles to electrode parts 17 on the polyimide film
substrate 14. A surface treatment method for the polyimide film
substrate 14 having the above constitution will be described
below.
[0008] The polyimide film substrate 14 is placed on the RF
electrode 5. A RF(Radio-Frequency) of 200 W is applied to the RF
electrode 5 while a degree of vacuum in the vacuum chamber 1 is
kept to be 30 Pa with 50 SCCM of an oxygen gas supplied from the
gas introduction port 2. As a result, plasma is generated. Oxygen
radicals or oxygen ions present in the plasma are irradiated onto a
surface of the polyimide film substrate 14 exposed in the plasma.
The oxygen radicals react with contamination organic substances
adhering on the polyimide film substrate 14, whereby the
contamination organic substances are decomposed to be sublimation
compounds such as CO.sub.2 or the like and then removed. Further,
functional groups such as C.dbd.O, COOH and the like are generated
on the surface of the polyimide film substrate 14, activating the
surface of the polyimide film substrate. The bonding strength
between the polyimide film substrate 14 and the ACF 15 is improved
accordingly.
[0009] In the case of polyimide film substrate 14, residual ions of
chlorine or the like are left yet on the polyimide film substrate
14 when the apparatus receives the polyimide film substrate 14. The
reason for this is that hydrochloric acid is used as one of
components of a plating solution for forming a pattern of the
electrodes 17 on the polyimide film substrate 14 by plating, and,
for example, chlorine ions are left if the substrate is not fully
cleaned by water after the pattern is formed. In the event that the
IC 16 is connected with the use of the ACF 15 to the polyimide film
substrate 14 having the residual ions, the residual ions cause
corrosion and electrical failures such as ion migration, etc. As
such, the plasma treatment is carried out to remove the chlorine
ions.
[0010] However, if the plasma treatment is carried out to the
substrate 6 before subjected to wire bonding, not only the organic
contaminant, inorganic substance, or the like, but the substrate 6
is sputtered by argon ions simultaneously. In the case of the
substrate 6 formed of glass cloth epoxy resin, Br (bromine)
included in the substrate 6 adheres again to the substrate after
separated from the substrate 6 by the plasma treatment. In the case
of the Br adheres to the electrode 10, the trouble is that the Br
adhering on the electrode 10 reacts with moisture in the air and
becomes HOBr or HBr when the substrate 6 is exposed to the
atmosphere, which causes corrosion of the electrode 10.
[0011] When the plasma treatment is carried out with the aim of
removing residual ions adhering to the polyimide film substrate 14,
since there is no means for observing whether or not the residual
ions are actually removed, the plasma treatment may be executed to
an excessive stage in order to perfectly remove the residual ions.
Thus the trouble is that the excessive plasma treatment damages
also the polyimide film substrate 14.
SUMMARY OF THE INVENTION
[0012] Accordingly, the present invention is devised to solve the
above-discussed problems inherent in the conventional art and an
object of the present invention is to provide an apparatus and a
method for surface treatment to substrates whereby the substrates
quality can be maintained by preventing an excessive plasma
treatment to the substrates.
[0013] In accomplishing the above objective, according to a first
aspect of the present invention, there is provided a substrate
surface treatment apparatus for executing surface treatment to a
substrate arranged in a reaction chamber by ions in plasma
generated in the reaction chamber, which comprises:
[0014] a detecting device arranged to the reaction chamber for
detecting at least either whether or not components constituting
the substrate are separated from the substrate, or whether or not
impurities adhering to a surface of the substrate are removed by
the surface treatment; and a controller connected to the detecting
device for controlling to reduce an energy of the ions in the
plasma on a basis of the detected information by the detecting
device when the separation of components is brought about, and for
controlling to terminate the surface treatment on a basis of the
detected information by the detecting device when the removal of
impurities ends.
[0015] The substrate surface treatment apparatus may be further
provided with a plasma generating device including electrodes
arranged in the reaction chamber for generating the plasma and a
power supply unit for supplying electricity to the electrodes,
and
[0016] a vacuum degree adjusting device connected to the reaction
chamber for adjusting a degree of vacuum in the reaction
chamber,
[0017] wherein the controller controls operations of the power
supply unit and the vacuum degree adjusting device on the basis of
the detected information by the detecting device so as to control
to reduce the energy of the ions and to end the surface
treatment.
[0018] The above detecting device may be comprised of a
spectroscopic analyzer for conducting spectral observation of light
generated by the plasma and detecting the components and the
impurities of the substrate on a basis of the observation.
[0019] The above detecting device may be comprised of a mass
analyzer for analyzing gas elements in the reaction chamber and
detecting the components and the impurities of the substrate on a
basis of the gas analysis.
[0020] The components of the substrate to be detected by the
detecting device may be bromine (Br).
[0021] The impurities to be detected by the detecting device may be
chlorine.
[0022] According to a second aspect of the present invention, there
is provided a substrate surface treatment method for executing
surface treatment to a substrate arranged in a reaction chamber by
ions in plasma generated in the reaction chamber, which
comprises:
[0023] detecting at least either whether or not components
constituting the substrate are separated from the substrate by the
surface treatment, or whether or not impurities adhering to a
surface of the substrate are removed by the surface treatment;
and
[0024] controlling on a basis of the detected information an energy
of the ions in the plasma to reduce when the separation of
components is detected to take place and the surface treatment to
end when the removal of impurities is detected to end.
[0025] By the above construction of the aspects of the present
invention, there are provided the detecting device and the
controller, so that the energy of ions in the plasma is controlled
to decrease when the constituent separated from the substrate is
detected, and the surface treatment to the substrate is controlled
to terminate when the completion of removing impurities adhering to
the substrate is detected. In the arrangement as above, the
constituent of the substrate can be prevented from separating and
scattering from the substrate. Therefore the phenomenon that the
separated constituent from the substrate adheres again to the
substrate and the redeposit of the separated constituent causes
corrosion to the substrate is avoided. Furthermore, the ions are
prevented from excessively irradiated to the substrate when the
removal of impurities is completed, therefore reducing damages to
the substrate.
[0026] The first embodiment and the second embodiment of the
present invention enable preventing the excessive plasma treatment
to substrates and maintaining quality of the substrates.
[0027] When the plasma generating device and the vacuum degree
adjusting device are provided additionally, the controller can
control the power supply unit installed to the plasma generating
device and the vacuum degree adjusting device on the basis of
detected information by the detecting device. In other words, the
power to be supplied to the electrode in the plasma generating
device is reduced by controlling the power supply unit, so that the
energy of ions in the plasma can be decreased. As a result, the
efficiency for sputtering can be lowered. Moreover, a collision
probability between gas molecules and ions in the reaction chamber
increases by raising the pressure in the reaction chamber by the
vacuum degree adjusting device, and eventually the energy of the
ions can be decreased. Furthermore, the plasma treatment can be
stopped by, e.g., stopping the power supply.
[0028] When the spectroscopic analyzer is used as the detecting
device, the detecting device can be arranged to the outside of the
reaction chamber, and the whole constitution of the substrate
surface treatment apparatus is simplified.
[0029] When the mass analyzer is used as the detecting device, the
constituent and impurities of the substrate can be detected more
highly accurately than by the spectroscopic analyzer, thus enabling
the quality of the substrate to be maintained at a high level.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] These and other objects and features of the present
invention will become clear from the following description taken in
conjunction with the preferred embodiments thereof with reference
to the accompanying drawings in which:
[0031] FIG. 1 is a schematic diagram of the configuration of a
surface treatment apparatus for substrates according to a first
embodiment of the present invention;
[0032] FIG. 2 is a schematic diagram of the configuration of a
surface treatment apparatus for substrates according to a second
embodiment of the present invention;
[0033] FIG. 3 is a schematic diagram of the configuration of a
conventional surface treatment apparatus for substrates;
[0034] FIG. 4 is a diagram showing the constitution of a substrate
electrode; and
[0035] FIG. 5 is a diagram for briefly explaining bonding when an
IC chip is bonded via an ACF to a film substrate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] An apparatus for surface treatment to substrates and a
method for surface treatment to substrates which is carried out by
the apparatus according to the preferred embodiments of the present
invention will be described below with reference to the attached
drawings. It is to be is noted that like parts are designated by
like reference numerals throughout the accompanying drawings.
[0037] First Embodiment
[0038] FIG. 1 is a schematic diagram showing the constitution of a
substrate surface treatment apparatus 101 according to a first
embodiment. Roughly speaking, the apparatus 101 has a reaction
chamber 110, a plasma generating device 120, a vacuum degree
adjusting device 130, a detecting device 140, and a controller 150.
The reaction chamber 110 in which a substrate 109 is stored is a
vessel for carrying out surface treatment by plasma to the
substrate 109, which comprises a reaction gas introduction port
111, an exhaust port 112 and an observation window 113, and is
grounded. To the reaction gas introduction port 111 is connected a
reaction gas supply unit 161 which supplies a reaction gas for
generating desired ions into the reaction chamber 110 via the
reaction gas introduction port 111. The reaction gas supply unit
161 is controlled to operate by the controller 150.
[0039] Inside the reaction chamber 110, there is arranged an
electrode 121 via an insulating ring 162 to a side wall 110a of the
reaction chamber 110. The electrode 121 is constituted so that the
substrate 109 can be placed on the electrode 121. O rings are
interposed between the electrode 121 and the insulating ring 162
and between the insulating ring 162 and the side wall 110a, whereby
the reaction chamber 110 is kept in vacuum. Moreover, a cooling
groove 163 for passing a coolant, e.g., cooling water is formed in
the side wall llOa so as to prevent the O rings from being heated
to 200.degree. C. or more. A coolant supply unit 164 which is
controlled in operation by the controller 150 for supplying the
coolant, i.e., cooling water in this embodiment is connected to the
cooling groove 163.
[0040] Also in the reaction chamber 110, an opposed electrode 122
which is grounded is arranged opposite to the electrode 121. A
RF(Radio-Frequency) is applied to the electrode 121 by a power
supply unit 123 including a matching tuner and a RF power supply
part. The plasma generating device 120 is constituted of the
electrode 121, the opposed electrode 122 and the power supply unit
123. The power supply unit 123 is controlled to operate by the
controller 150. Plasma can be generated between the electrode 121
and the opposed electrode 122 by supplying the RF to the electrode
121 in the reaction chamber 110 to which a predetermined reaction
gas is supplied in a vacuum state.
[0041] According to the embodiment, an emission spectroscopic
analysis device 141 is arranged as an example of a spectroscopic
analyzer and the detecting device 140 for observing a state of the
plasma in the reaction chamber 110 from the outside of the
apparatus, more specifically, for observing an emission state of
the plasma from the outside of the apparatus. The emission
spectroscopic analysis device 141 is disposed adjacent to the
observation window 113. Although described in detail later, the
detecting device 140 detects at least either whether or not
components constituting the substrate 109 are separated from the
substrate 109 by the surface treatment carried out to the substrate
109 with the utilization of the plasma, or whether or not
impurities adhering to a surface of the substrate 109 are removed
by the surface treatment.
[0042] The vacuum degree adjusting device 130 connected to the
reaction chamber 110 is a device for adjusting a degree of vacuum
in the reaction chamber 110. The vacuum degree adjusting device 130
has a valve 131 for shutting the inside from the outside of the
reaction chamber 110, more precisely, for shutting the inside from
a vacuum pump 133 to be described below, a valve switch 132 for
controlling an opening degree of the valve 131, and the vacuum pump
133 for turning the interior of the reaction chamber 110 to vacuum
via the valve 131. As will be detailed later, the vacuum degree
adjusting device 130 adjusts the degree of vacuum inside the
reaction chamber 110 in accordance with a control signal sent from
the controller 150 on a basis of detected information sent from the
detecting device 140, namely, the emission spectroscopic analysis
device 141 in the embodiment to the controller 150. Specifically,
the control signal is supplied to the valve switch 132, whereby the
valve 131 is opened at the opening degree conforming to the control
signal. The degree of vacuum in the reaction chamber 110 is
adjusted in this manner.
[0043] Operation, i.e., the surface treatment method in the
above-constituted substrate surface treatment apparatus 101 will be
depicted below. The controller 150 carries out control related to
the substrate surface treatment method. The following description
is based on a state in which the substrate 109 is already placed on
the electrode 121.
[0044] While the air in the reaction chamber 110 is discharged by
the vacuum pump 133, 50 SCCM of an argon gas is supplied from the
reaction gas introduction port 111 by the reaction gas supply unit
161 so that the reaction chamber 110 is held in a degree of vacuum
of 30 Pa. In this state, 200 W RF(Radio-Frequency) is applied to
the electrode 121 from the power supply unit 123 to generate plasma
between the electrode 121 and the opposed electrode 122 in the
reaction chamber 110. Argon ions present in the plasma are
irradiated to the surface of the substrate 109 exposed in the
plasma. Although nickel hydroxide or the like is deposited onto a
surface of the electrode 10, which is formed of gold on the
substrate 109 in the same constitution as that described with
reference to FIG. 4, through a heat process or the like as
discussed in the "BACKGROUND OF THE INVENTION", the nickel
hydroxide or the like is removed by the sputtering action because
of the irradiation of argon ions, and therefore, the surface of the
electrode 10 formed of gold is cleaned.
[0045] At this time, the surface of the substrate 109 except the
electrode 10 is also sputtered by the irradiation of argon ions. In
the case where the substrate 109 is formed of glass cloth epoxy
resin, Br (bromine) as one of components constituting the substrate
109 is sputtered as well, emitted into the reaction chamber 110. So
there is apprehension that the emitted Br adheres again to the
surface of the substrate 109.
[0046] Meanwhile, according to the present embodiment, the plasma
state in the reaction chamber 110 is monitored at all times through
the observation window 113 by the emission spectroscopic analysis
device 141. The emission spectroscopic analysis device 141 sends a
signal to the controller 150 at a time point when an emission
spectrum of the Br is observed. The controller 150 in return
controls and adjusts the power supply unit 123 and the valve switch
132 to reduce an energy of argon ions in the plasma to prevent the
Br from being sputtered. More specifically, the controller 150
decreases an electric power to be supplied from the power supply
unit 123 to the electrode 121 and also drives the valve 131 in a
direction to close the valve to raise the pressure in the reaction
chamber 110. Since the energy of argon ions is reduced by
decreasing the electric power, whereby an efficiency for sputtering
can be deteriorated. At the same time, a collision probability
between gas molecules and the argon ions in the reaction chamber
110 is increased by raising the pressure, and eventually the energy
of argon ions is reduced. Thus the sputtering efficiency can be
decreased. Accordingly, only the nickel hydroxide deposited on the
electrode 10 of the substrate 109 can be removed by the sputtering
action through the irradiation of argon ions, while the Br
contained in the substrate 109 is prevented from being
sputtered.
[0047] The sputtering efficiency to the nickel hydroxide is
deteriorated by the reduction in the energy of argon ions as above.
But, where the nickel hydroxide is deposited is the surface of the
electrode 10 as mentioned above, and therefore the nickel hydroxide
is sputtered with priority by the irradiation of argon ions. In
contrast, since the Br is included in the substrate 109, amount of
Br to be sputtered is relatively small. That is, a sequence of the
above operations is based on an idea that the nickel hydroxide has
been removed as much as possible before the Br is emitted from the
substrate 109.
[0048] Since the nickel hydroxide can be removed from the surface
of the gold electrode 10 of the substrate 109, the bonding strength
between the gold electrode 10 and a wire can be improved when the
gold electrode 10 is to be wire bonded.
[0049] According to the embodiment as described hereinabove, in
processing the substrate 109 formed of glass cloth epoxy resin by
argon plasma, the plasma state in the reaction chamber 110 is
always monitored through the observation window 113 by the emission
spectroscopic analysis device 141, and the controller 150 controls
the power supply unit 123 and the valve switch 132 to adjust not to
sputter the Br when the emission spectrum of the Br is observed.
Therefore, only the nickel hydroxide deposited on the gold
electrode 10 of the substrate 109 can be removed by irradiating
argon ions while the Br as a constituent of the substrate 109 is
prevented from scattering. In consequence of this, the phenomenon
that the sputtered Br adheres again to the substrate 6 does not
arise, and the conventional trouble that the Br and the moisture in
the air react with each other when the substrate 6 having the Br
adhering to the electrode 10 is exposed to the atmosphere, thereby
forming HOBr or HBr, does not arise. Therefore the corrosion of the
electrode 10 of the substrate 109 can be prevented.
[0050] In the present embodiment, the controller 150 controls both
of the power supply unit 123 and the valve switch 132 when the
emission spectrum of the Br is observed. However, the
aforementioned effect is obtained by controlling at least one of
the power supply unit 123 and the valve switch 132 as is apparent
from the foregoing description.
[0051] The substrate 109 is formed of glass cloth epoxy resin in
the above description. Hereinbelow will be discussed the substrate
109 formed of a polyimide film.
[0052] As is described in the "BACKGROUND OF THE INVENTION", in the
case of the substrate 109 formed of a polyimide film, chlorine ions
are sometimes left as an example of impurities to the surface of
the substrate 109 if cleaning at a manufacturing time of the
substrate is insufficient. For removing the chlorine ions, an
oxygen gas is supplied by 50 SCCM into the reaction chamber 110
through the reaction gas introduction port 111 by the reaction gas
supply unit 161. While the degree of vacuum in the reaction chamber
110 is kept to be 30 Pa, 200 W RF(Radio-Frequency) is applied to
the electrode 121, thereby generating plasma. Oxygen ions present
in the plasma are irradiated onto the surface of the substrate 109
exposed in the plasma, which sputter and remove residual chlorine
ions on the surface of the substrate 109.
[0053] In the meantime, the plasma state in the reaction chamber
110 is monitored at all times by the emission spectroscopic
analysis device 141 through the observation window 113. The
emission spectroscopic analysis device 141 observes an emission
spectrum of chlorine. At a time point when the removal of
impurities terminates, that is, the emission spectrum of chlorine
disappears or the emission spectrum of chlorine decreases to a
level where no trouble is substantially brought about, the emission
spectroscopic analysis device 141 sends a signal to the controller
150, and the controller 150 controls the power supply unit 123, the
valve switch 132 and the reaction gas supply unit 161 to stop the
plasma treatment.
[0054] Since the chlorine ions remaining at the substrate 109
formed of the polyimide film can be removed in the manner as above,
the problems of corrosion by residual ions, electrical failures
such as ion migration or the like which are caused by connecting
the IC with the use of ACF in a state in which chlorine ions remain
can be prevented.
[0055] In addition, by observing the emission spectrum of chlorine
by the emission spectroscopic analysis device 141, the plasma
treatment to the substrate 109 is stopped when chlorine as
impurities is removed. Therefore, chlorine ions remaining at the
substrate 109 can be removed while the effect of oxygen ions to the
substrate 109 is restricted to a minimum. At the same time, since
the substrate 109 is formed of polyimide, an organic contaminant at
the polyimide surface can be removed by the oxygen radicals and
oxygen ions as described in the "BACKGROUND OF THE INVENTION", and
also functional groups such as C.dbd.O, COOH, etc. are formed to
the surface, thereby activating the surface of the substrate 109.
The bonding strength between the substrate and the ACF is improved
accordingly.
[0056] Second Embodiment
[0057] The above substrate surface treatment apparatus 101 is
exemplified in the arrangement of using the emission spectroscopic
analysis device 141 as the detecting device 140 as shown in FIG. 1.
The detecting device 140 is not limited to the emission
spectroscopic analysis device, and a mass analyzer 142 may be
employed as will be described below with reference to FIG. 2.
[0058] A substrate surface treatment apparatus 102 indicated in
FIG. 2 is constituted including the mass analyzer 142 in place of
the emission spectroscopic analysis device 141 installed to the
foregoing substrate surface treatment apparatus 101. The same parts
in the substrate surface treatment apparatus 102 as those of the
substrate surface treatment apparatus 101 are designated by the
same reference numerals, and omitted from the description. Only
different parts will be discussed below.
[0059] Since the emission spectroscopic analysis device 141 is
eliminated from the substrate surface treatment apparatus 102, no
observation window 113 is formed to the reaction chamber 110. On
the other hand, the mass analyzer 142 is mounted to the exhaust
port 112 communicating with the valve 131 from the reaction chamber
110 so as to analyze a plurality of gas elements present at the
exhaust port part 112, that is, in the reaction chamber 110. The
mass analyzer 142 is connected to the controller 150.
[0060] Operation, i.e., surface treatment method in the substrate
surface treatment apparatus 102 constituted as above will be
described hereinbelow. Comparing the substrate surface treatment
method in the apparatus 102 with that in the apparatus 101, only a
manner of detecting a detection object in the reaction chamber 110
is different while the operation and effect obtained in the
apparatus 102 are fundamentally equal to the operation and effect
exerted in the apparatus 101. Therefore, an operation of detecting
the detection object will be primarily depicted below, with the
rest being omitted from the description or roughly described.
[0061] In the case where the substrate 109 is formed of the glass
cloth epoxy resin material, an argon gas is supplied by 50 SCCM
into the reaction chamber 110 from the reaction gas introduction
port 111 while the air in the reaction chamber 110 is discharged by
the vacuum pump 133. In a state with the reaction chamber kept to
30 Pa of the degree of vacuum, 200 W RF is applied to the electrode
121 thereby generating plasma. Similar to the case of the substrate
surface treatment apparatus 101, argon ions in the plasma are
irradiated to the surface of the substrate 109, and nickel
hydroxide or the like deposited to the surface of the gold
electrode 10 is removed by sputtering. On the other hand, a
plurality of kinds of gases present in the reaction chamber 110 are
monitored by the mass analyzer 142 at all times after the reaction
chamber 110 reaches a specified degree of vacuum or when the plasma
is generated. The mass analyzer 142 sends a signal to the
controller 150 when the element Br separated from the substrate 109
formed of the glass cloth epoxy resin material and emitted to the
reaction chamber 110 is observed. Based on the supply of the
signal, the controller 150 controls the power supply unit 123 and
the valve switch 132 to prevent the Br from being sputtered.
Accordingly, only the nickel hydroxide deposited on the gold
electrode 10 of the substrate 109 can be removed by the irradiation
of argon ions without scattering the Br as a constituent of the
substrate 109. Corrosion of the electrode 10 caused by the Br can
be thus prevented.
[0062] The controller 150 controls both of the power supply unit
123 and the valve switch 132 when the mass analyzer 142 detects the
Br. However, the above-described effect can be obtained by
controlling at least one of the power supply unit 123 and the valve
switch 132.
[0063] If the substrate 109 is formed of a polyimide film, in order
to eliminate residual chlorine ions, the oxygen gas is supplied by
50 SCCM into the reaction chamber 110 while the air in the reaction
chamber 110 is discharged by the vacuum pump 133 so that the
reaction chamber 110 is kept to the degree of vacuum of 30 Pa. In
this state, 200 W RF is applied to the electrode 121, thereby
generating plasma. Oxygen ions present in the plasma are irradiated
onto the surface of the substrate 109 exposed in the plasma.
Residual chlorine ions on the surface of the substrate 109 are
hence removed.
[0064] The mass analyzer 142 always monitors gases present in the
reaction chamber 110. When impurities are completely removed, that
is, when the chlorine comes not to be detected in the embodiment or
when a concentration of the chlorine decreases to a level where no
trouble is brought about, the mass analyzer 142 sends a signal to
the controller 150. In response to the signal, the controller 150
controls the power supply unit 123, the valve switch 132 and the
reaction gas supply unit 161 to stop the plasma treatment.
[0065] As above, since it is enabled to remove the chlorine ions
remaining at the substrate 109 formed of the polyimide film, this
can prevent corrosion by residual ions, electrical failures such as
ion migration or the like which are to be caused if the IC is
connected with the use of ACF in a state with the chlorine ions
remaining. Moreover, since the plasma treatment to the substrate
109 is stopped when the removal of the chlorine is completed as
described hereinabove, it is possible to remove the chlorine ions
remaining at the substrate 109 while the effect of oxygen ions to
the substrate 109 is limited to a minimum. At the same time, since
the substrate 109 is formed of polyimide, as discussed in the
"BACKGROUND OF THE INVENTION", the organic contaminant on the
polymide surface can also be removed by the oxygen radicals and the
oxygen ions, and functional groups such as C.dbd.O, COOH and the
like are formed to the surface, whereby the bonding strength
between the substrate and the ACF is improved.
[0066] The element within the substrate 109 controlled to emit from
the substrate 109 is Br in the foregoing embodiments. However, the
substrate surface treatment apparatuses 101 and 102 in the
embodiments can be applied to the other corrosive elements.
Similarly, although the element adhering to the substrate 109 is
chlorine in the foregoing embodiments, the apparatuses 101 and 102
of the embodiments are applicable to the other elements as
well.
[0067] In each of the above embodiments, suppressing the emission
of the element Br in the substrate 109, and removing the chlorine
adhering to the substrate 109 are described separately from each
other. Needless to say, however, suppressing the emission of
substrate constituents and removing impurities of the substrate may
be carried out simultaneously by detecting a plurality of elements
by the detecting device 140 such as the above emission
spectroscopic analysis device 141, the mass analyzer 142, etc.
[0068] Although the reaction gas injected to the reaction chamber
110 is the argon and the oxygen respectively in the embodiments as
above, the present invention is not restricted to the specific kind
of gas, and for instance, a mixed gas of argon and oxygen, hydrogen
or nitrogen gas is utilizable. It is to be noted, however, that the
reaction gas should be selected in some cases from a view point of
a relationship with the substance to be processed by the surface
treatment, because it is necessary to generate ions or the like
effective for the substance to be processed by the surface
treatment.
[0069] In each embodiment, the grounded opposed electrode 122 is
arranged in the reaction chamber 110. The grounded reaction chamber
110 may be adapted to function by itself as an opposed electrode,
and the opposed electrode 122 can be eliminated depending on the
circumstances.
[0070] Although the present invention has been fully described in
connection with the preferred embodiments thereof with reference to
the accompanying drawings, it is to be noted that various changes
and modifications are apparent to those skilled in the art. Such
changes and modifications are to be understood as included within
the scope of the present invention as defined by the appended
claims unless they depart therefrom.
* * * * *