DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the
first inventor to file provisions of the AIA .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Status of Claims
Claims 1-4 and 6-20 are pending
Claims 1, 4, 6, 7, and 14-16 have been amended
Claim 5 has been canceled
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1, 4, and 8-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Guha et al. (US 20150017810) in view of Ma et al. (US 20180358208), Collins et al. (US 20160276134), and Fung et al. (US 20170053811), with Chen et al. (US 20160293386), Class et al. (US 4422896), Ide (US 20060090704), Ui et al. (US 5976992), and Ludviksson (US 20060255260) as evidentiary references.
Regarding Claim 1:
Guha teaches a plasma etching apparatus comprising: a plasma generating source (upper sub-chamber 502); an ionization space (space between grids 551 and 552) coupled to the plasma generating source and configured to generate ions (plasma is generated in upper sub-chamber 502); a first grid (upper grid 551) between the ionization space and the plasma generating source; an acceleration space (lower sub-chamber 503) coupled to the ionization space and configured to deliver the ions to a substrate in the acceleration space (ions are accelerated from the upper sub-chamber to the lower sub-chamber); a substrate support (chuck 517) for supporting the substrate in the acceleration space, wherein the substrate support is configured to be biased (the electrostatic chuck used to support the substrate may be negatively biased to attract positive ions onto the substrate's surface); and a controller (a system controller may control some or all of the operations) configured with instructions for performing the following operations: introduce a noble gas into the plasma generating source; ignite plasma of the noble gas (plasma may be generated in the upper sub chamber 502; the plasma may be generated from an inert gas such as argon); a negative bias to the substrate support to etch modified materials on the substrate (the electrostatic chuck used to support the substrate may be negatively biased to attract positive ions onto the substrate's surface and bombard the surface of the substrate in order to activate the surface for reaction) [Fig. 5 & 0036, 0057, 0069, 0075-0076, 0089, 0090, 0093, 0098, 0102].
Guha does not specifically disclose wherein the one or more gas sources are configured to supply an electronegative reactive gas and a non-reactive gas to the ionization space; and a controller configured with instructions for performing the following operations: introduce the electronegative reactive gas and the non-reactive gas to the ionization space from the one or more gas sources.
Ma teaches wherein the one or more gas sources (first and second gas ports 118 and 121, which feed first gas 210 and second gas 220, respectively) are configured to supply an electronegative reactive gas and a non-reactive gas to the ionization space (an inert gas can be delivered through the gas ports. Different gases may also flow through the two ports. The chemical composition of the fed gases can be chosen and controlled) [Fig. 5 & 0059-0060, 0067]; wherein the apparatus is configured to introduce the electronegative reactive gas and the non-reactive gas to the ionization space from the one or more gas sources (an inert gas can be delivered through the gas ports. Different gases may also flow through the two ports. The chemical composition of the fed gases can be chosen and controlled) [Fig. 5 & 0059-0060, 0067].
Guha and Ma are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the apparatus of Guha to further include one or more gas sources coupled to the ionization space, as in Ma, to provide further control over process uniformity [Ma - 0057, 0059]. It is noted that Guha discloses that its plasma may be generated from a combination of inert and reactive gases (inert gases such as Ar, He, Ne, Kr and Xe; reactive gases such as hydrogen, oxygen, and nitrogen. One or more of the inert gases listed may be used) [Guha - 0043].
Modified Guha does not specifically disclose accelerate negative ions of the electronegative reactive gas to the substrate in the acceleration space by applying a positive bias to the substrate support to modify materials on the substrate.
Collins discloses accelerate negative ions of the electronegative reactive gas to the substrate in the acceleration space by applying a positive bias to the substrate support to modify materials on the substrate (a bias voltage may be applied to the pedestal 110 to selectively or alternately extract positive and/or negative ions from said plasma and accelerate those ions at desired energy levels to impact the surface of the workpiece 111 for etching, cleaning, deposition, or other materials modification. At least some electrons are also flowed to the lower chamber 100b) [Fig. 1 & 0063, 0087].
Modified Guha and Collins are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the controller of Modified Guha to have instructions for positively biasing a substrate support, as in Collins, to provide further control over substrate modification [Collins - 0063]. Chen et al. (US 20160293386) also discloses that selective control over positive and negative ion attraction can help minimize the effects of charge accumulation [Chen - 0005, 0046].
Modified Guha does not specifically disclose quenching the plasma of the noble gas.
Fung teaches quenching the plasma of the noble gas (RF power supplied for generating plasma is supplied in duty cycles, wherein there are on and off periods) [Fig. 12A, 12B& 0069-0070].
Modified Guha and Fung are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the apparatus of Guha to include periods of time where plasma is quenched, as in Fung, to provide control over etchant concentrations [Fung - 0041, 0053, 0063, 0094]. Accordingly, Fung also discloses that plasma duty cycle is a result effective variable. Specifically, the on and off periods for plasma generation can be controlled to control etchant concentration. As such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to find an optimum duty cycle to obtain a desired etching profile (therefore, plasma can be quenched at any desired point in time, such as prior to support biasing). It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. See MPEP 2144.05.
It is noted that the limitations “generate negative ions of the electronegative reactive gas in the ionization space using electrons extracted from the plasma of the noble gas, generate positive ions of the non-reactive gas in the ionization space using metastable neutral species that diffuse from the plasma of the noble gas after the plasma of the noble gas is quenched,” would be disclosed by the combination of references. Specifically, Collins discloses biasing a support to attract respective species [Collins - Fig. 1 & 0063, 0087]. Guha discloses forming a plasma from a noble gas [Guha – 0043]. Fung discloses that plasma duty cycle is a result effective variable [Fung - 0041, 0053, 0063, 0094]. As such, the combination of references discloses biasing a support to attract electrons from a noble gas plasma, and it also discloses biasing a support to diffuse neutral species after plasma is quenched. The instant application also discloses biasing of the support, which in turn causes ionization via extraction of species through the grids [IA – 0048-0050, 0056]. Since the combination of references is performing the same steps as the instant application, the result of negative ion generation would occur.
PNG
media_image1.png
830
705
media_image1.png
Greyscale
It is also noted that the controller limitations of claim 1 that are boxed (as shown in the annotated drawing above) are what the examiner considers structural programming, and as such, would have structural weight in the apparatus (i.e., the process steps that are positively recited). The portions of the controller limitations that are not boxed are considered intended results of steps that are positively recited. The court noted that a "‘whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.’" Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)). As such, the combination of references need only be capable of performing the intended results.
Regarding “using electrons extracted from the plasma of the noble gas, using metastable neutral species that diffuse from the plasma of the noble gas,” the examiner would like to note that the instant application does not provide specific support for the code of the program of the controller to directly ionize the gases. Rather, the controller discloses that through biasing of the support, respective species may be extracted through the grids such that reactions occur that result in the formation of the respective ions [IA – 0048-0050, 0056]. Collins discloses selective biasing of the substrate support, therefore negative, neutral, and positive particles would be extracted from the plasma through respective grid plates [Collins – 0063, 0087]. Guha discloses applying a negative bias to the electrostatic chuck [Guha - 0076]. Guha also discloses that plasma may be generated in the upper sub chamber 502; the plasma may be generated from an inert gas such as argon, or a combination of gases such as argon and oxygen [Guha – 0043]. Ma discloses feeding a combination of gases between grids (the gases can be chosen and controlled, and since Guha discloses that gases such as oxygen and argon can be used in its apparatus, feeding oxygen/argon between grids would be obvious) [Ma - 0059-0060, 0067]. Since the combination of references discloses a noble gas plasma that is quenched (of which, electrons and metastable species would be present), the application of a support bias would extract those electrons and metastable species and cause those electrons/metastable species to interact with other substances along the way (see the evidentiary references listed below). Therefore, since the combination of references is performing the same steps as the instant application, the intended result would occur.
Furthermore, Class et al. (US 4422896) discloses that the electron-molecule collisions in a plasma convert molecular oxygen to atomic oxygen, as well as positive and negative oxygen ions [Col. 2 lines 30-40]. Ide (US 20060090704) discloses that in oxygen plasma, the electrons generated by dissociation are also consumed in the production of negative ions [Ide - 0065 - 0069]. Ui et al. (US 5976992) discloses that when a rare gas such as argon is added to oxygen plasma, part of the rare gas is turned into a metastable excited state, which then acts upon oxygen atoms to ionize through penning ionization [Ui - Col. 12 lines 25-37]. Ludviksson (US 20060255260) also discloses that a gas such as helium can be excited to collide with neutral molecules to produce positive ions [Ludviksson - 0032-0037].
In summary, the instant application does not provide support for the programming of the controller specifically to form the respective ions, but rather, it has support for controlling biasing of the support, which in turn causes ionization via extraction of species through the grids [IA – 0048-0050, 0056]. The combination of references does disclose biasing of the support and noble gas plasma generation and would therefore disclose the formation of the respective species. So while the combination of references may not explicitly disclose the formation of the respective species, since the combination of references discloses all of the steps that are positively recited (biasing of the support, generation of plasma from a noble gas, feeding an electronegative gas), the intended results would occur.
Regarding Claim 4:
Guha teaches in connection with accelerating the positive ions of the electronegative non-reactive gas (the electrostatic chuck used to support the substrate may be negatively biased to attract positive ions onto the substrate's surface), etch the material layer of the substrate (the substrate is etched; Fig. 3A-3F shows layer to be etched 12) wherein the material layer includes a dielectric material or electrically conductive material (the layer to be etched 12 is a cobalt-platinum alloy) [Figs. 3A-3F 0008, 0028].
Modified Guha (Guha modified by Ma) does not specifically disclose accelerating negative ions of the reactive gas to the substrate.
Collins discloses accelerating negative ions of the reactive gas to the substrate in the acceleration space by applying a positive bias to the substrate support to modify materials on the substrate (a bias voltage may be applied to the pedestal 110 to selectively or alternately extract positive and/or negative ions from said plasma and accelerate those ions at desired energy levels to impact the surface of the workpiece 111 for etching, cleaning, deposition, or other materials modification. At least some electrons are also flowed to the lower chamber 100b) [Fig. 1 & 0063, 0087].
Modified Guha and Collins are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the controller of Modified Guha to have instructions for positively biasing a substrate support, as in Collins, to provide further control over substrate modification [Collins - 0063]. Chen et al. (US 20160293386) also discloses that selective control over positive and negative ion attraction can help minimize the effects of charge accumulation [Chen - 0005, 0046].
It's further noted that the combination of references would disclose an apparatus capable of performing the intended result of "form a reactive layer on a material layer of the substrate.” The examiner considers this limitation as the intended result of the other process steps that have been positively recited. Collins discloses selective biasing of the substrate support, therefore negative and positive particles would be extracted from the plasma through respective grid plates [Collins – 0063, 0087]. As such, since the instant application also forms a reactive layer on a material layer of the substrate via negative ion attraction via support biasing, the combination of references would also be capable of forming the reactive layer as claimed. The court noted that a "‘whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.’" Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)).
Regarding Claim 8:
Guha teaches wherein the first grid is configured to be biased or grounded (a negative bias is applied to the upper grid 551), and wherein the controller is further configured with instructions for performing the following operations: in connection with accelerating the positive ions, form a strong electric field between the first grid and the substrate support (the substrate support may be negatively biased) [Fig. 1, 2, 5 & 0022, 0026, 0076].
Modified Guha (Guha modified by Ma) does not specifically wherein the controller is further configured with instructions for performing the following operations: in connection with accelerating the negative ions, form a weak electric field between the first grid and the substrate support.
Collins teaches wherein the controller is further configured with instructions for performing the following operations: in connection with accelerating the negative ions, form a weak electric field between the first grid and the substrate support (a bias voltage may be applied to the pedestal 110 to selectively or alternately extract positive and/or negative ions from said plasma and accelerate those ions at desired energy levels to impact the surface of the workpiece 111 for etching, cleaning, deposition, or other materials modification. At least some electrons are also flowed to the lower chamber 100b) [Fig. 1 & 0063, 0087].
Modified Guha and Collins are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the controller of Modified Guha to have instructions for positively biasing a substrate support, as in Collins, to provide further control over substrate modification [Collins - 0063]. Chen et al. (US 20160293386) also discloses that selective control over positive and negative ion attraction can help minimize the effects of charge accumulation [Chen - 0005, 0046].
Regarding Claim 9:
Claim 9 is merely intended use and are given weight to the extent that the prior art is capable of performing the intended use. A claim containing a “recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus” if the prior art apparatus teaches all the structural limitations of the claim. Ex parte Masham, 2 USPQ2d 1647 (Bd. Pat. App. & Inter. 1987). It is noted that the process chamber of Modified Guha would be capable of accommodating a variety of different wafers. It’s also noted that the combination of references teach the process steps of applying negative and positive biases to selectively accelerate positive and negative ions, thus the prior art would be capable a high aspect ratio substrate,
Regarding Claim 10:
Guha teaches a second grid (lower grid 552) between the ionization space and the acceleration space [Fig. 5 & 0089].
Regarding Claim 11:
The limitations “wherein a pressure in the ionization space is greater than a pressure in the acceleration space” are merely intended use and are given weight to the extent that the prior art is capable of performing the intended use. A claim containing a “recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus” if the prior art apparatus teaches all the structural limitations of the claim. Ex parte Masham, 2 USPQ2d 1647 (Bd. Pat. App. & Inter. 1987). It is noted that the pressure in the sub chambers of Guha are set to be different, therefore the apparatus would be capable of setting the pressure of the space between grids 551 and 552 to be higher than the pressure of the lower-sub chamber.
Regarding Claim 12:
Guha teaches wherein the second grid is configured to be biased (power supply 567 can supply a bias to lower grid 552) [Fig. 5 & 0089].
Regarding Claim 13:
Guha teaches wherein the plasma generating source is an inductively coupled plasma (ICP) reactor (plasma is generated in upper sub-chamber 502 via coil 533) [Fig. 5 & 0091, 0093].
Regarding Claim 14:
Modified Guha (Guha modified by Ma) does not specifically disclose wherein the controller is further configured with instructions for performing the following operations: repeat and alternate operations of accelerating the negative ions of the reactive gas and accelerating the positive ions of the non-reactive gas.
Collins teaches wherein the controller is further configured with instructions for performing the following operations: repeat and alternate operations of accelerating the negative ions of the reactive gas and accelerating the positive ions of the non-reactive gas (the bias voltage supplied to the support pedestal 110 is a waveform of low repetition frequency; bias that is applied may alternate between attracting positive or negative ions) [Fig. 1 & 0063].
Modified Guha and Collins are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the controller of Modified Guha to have instructions for positively biasing a substrate support, as in Collins, to provide further control over substrate modification [Collins - 0063]. Chen et al. (US 20160293386) also discloses that selective control over positive and negative ion attraction can help minimize the effects of charge accumulation [Chen - 0005, 0046].
Claim(s) 2-3, 6-7, and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Guha et al. (US 20150017810) in view of Ma et al. (US 20180358208), Collins et al. (US 20160276134), and Fung et al. (US 20170053811), with Chen et al. (US 20160293386), Class et al. (US 4422896), Ide (US 20060090704), Ui et al. (US 5976992), and Ludviksson (US 20060255260) as evidentiary references, as applied to claims 1, 4, and 8-14 above, and further in view of Wilson et al. (US 20070193975).
The limitations of claims 1, 4, and 8-14 have been set forth above.
Regarding Claim 2:
Modified Guha does not specifically disclose wherein the negative bias is substantially greater in absolute value than the positive bias.
Although Wilson does not specifically disclose “wherein the negative bias is substantially greater in absolute value than the positive bias,” Wilson does disclose that voltage amplitude is a result effective variable. Specifically, the shape, frequency, amplitude and duration of voltage pulses can be adjusted depending on the etching performance [Wilson - 0040]. Modified Guha and Wilson are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to find an optimum amplitude for the biases to obtain a desired etching performance. It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. See MPEP 2144.05.
Regarding Claim 3:
Modified Guha does not specifically disclose wherein the positive bias is between about 0.5 V and about 10 V, and wherein the negative bias is between about -50 kV and about -1 kV.
Although Wilson does not specifically disclose “wherein the positive bias is between about 0.5 V and about 10 V, and wherein the negative bias is between about -50 kV and about -1 kV,” Wilson does disclose that voltage amplitude is a result effective variable. Specifically, the shape, frequency, amplitude and duration of voltage pulses can be adjusted depending on the etching performance [Wilson - 0040]. Modified Guha and Wilson are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to find an optimum amplitude for the biases to obtain a desired etching performance. It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. See MPEP 2144.05.
Regarding Claim 6:
Modified Guha would disclose wherein the controller is further configured with instructions for performing the following operations: extract electrons from the plasma of the noble gas to the ionization space. Specifically, Collins discloses biasing a support to attract respective species [Collins - Fig. 1 & 0063, 0087]. Guha discloses forming a plasma from a noble gas [Guha – 0043]. As such, the combination of references discloses biasing a support to attract electrons from a noble gas plasma. The instant application also discloses biasing of the support, which in turn causes ionization via extraction of species through the grids [IA – 0048-0050, 0056]. Since the combination of references is performing the same steps as the instant application, the result of negative ion generation would occur.
It is noted that the examiner considers the limitations “to ionize the reactive gas and form the negative ions of the electronegative reactive species in the ionization space,” as the intended results of the other process steps that have been positively recited. The examiner does not consider the generation of the ions as requiring their own controller programming; the instant specification does not provide specific support for the code of the program of the controller to directly perform the aforementioned limitations. Rather, the controller of the instant application controls biasing of the support, which in turn causes ionization via extraction of species through the grids [IA – 0048-0050]. As such, the combination of references need only be capable of performing the intended results. The court noted that a "‘whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.’" Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)). It’s further noted that the pressure in the lower sub-chamber of Guha may be lower than the pressure in the upper sub-chamber (it can be reasonably inferred that since the lower sub-chamber's pressure is lower than the upper sub-chamber's, the pressure of the space between grids 551 and 552 will be higher than the pressure of the lower-sub chamber), as such, the combination of references would be able to move any other particles via pressure differential [Guha - Fig. 5 & 0081].
Furthermore, Class et al. (US 4422896) discloses that the electron-molecule collisions in a plasma convert molecular oxygen to atomic oxygen, as well as positive and negative oxygen ions [Col. 2 lines 30-40]. Ide (US 20060090704) discloses that in oxygen plasma, the electrons generated by dissociation are also consumed in the production of negative ions [Ide - 0065 - 0069]. Ui et al. (US 5976992) discloses that when a rare gas such as argon is added to oxygen plasma, part of the rare gas is turned into a metastable excited state, which then acts upon oxygen atoms to ionize through penning ionization [Ui - Col. 12 lines 25-37]. Ludviksson (US 20060255260) also discloses that a gas such as helium can be excited to collide with neutral molecules to produce positive ions [Ludviksson - 0032-0037].
Regarding Claim 7:
The examiner considers the limitation “wherein the controller is further configured with instructions for performing the following operations: cause diffusion of metastable neutral species from the plasma of the noble gas to the ionization space to ionize the non-reactive gas and form the positive ions of the non-reactive gas in the ionization space,” as the intended results of the other process steps that have been positively recited. The examiner does not consider the generation of the ions as requiring their own controller programming; the instant specification does not provide specific support for the code of the program of the controller to directly perform the aforementioned limitations. Rather, the controller discloses that through negative biasing of the support, the neutral species may be extracted [IA – 0050, 0056]. Guha discloses applying a negative bias to the electrostatic chuck [Guha - 0076]. Guha also discloses that plasma may be generated in the upper sub chamber 502; the plasma may be generated from an inert gas such as argon, or a combination of gases such as argon and oxygen [Guha – 0043]. As such, the combination of references discloses the positively recited step of negatively biasing a support. Therefore, since the combination of references is performing the same steps as the instant application, the intended result would occur. The court noted that a "‘whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.’" Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)). As such, the combination of references need only be capable of performing the intended results.
Regarding Claim 15:
Modified Guha does not specifically disclose wherein the controller is further configured with instructions for performing the following operations: in connection with accelerating the negative ions of the electronegative reactive gas, accelerate the negative ions of the electronegative reactive gas for a first duration between about 1 ms and about 10 ms, and in connection with accelerating the positive ions of the non-reactive gas, accelerate the positive ions of the non-reactive gas for a second duration between about 1 ms and about 10 ms.
Although Wilson does not specifically disclose “wherein the controller is further configured with instructions for performing the following operations: in connection with accelerating the negative ions of the reactive gas, accelerate the negative ions of the reactive gas for a first duration between about 1 ms and about 10 ms, and in connection with accelerating the positive ions of the non-reactive gas, accelerate the positive ions of the non-reactive gas for a second duration between about 1 ms and about 10 ms.” Wilson does disclose that bias duration is a result effective variable. Specifically, the shape, frequency, amplitude and duration of voltage pulses can be adjusted depending on the etching performance [Wilson - 0040]. Modified Guha and Wilson are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to find an optimum duration for the biases to obtain a desired etching performance. It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. See MPEP 2144.05.
Claim(s) 16-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Guha et al. (US 20150017810) in view of Ma et al. (US 20180358208), Collins et al. (US 20160276134), Wilson et al. (US 20070193975), and Fung et al. (US 20170053811), with Chen et al. (US 20160293386), Class et al. (US 4422896), Ide (US 20060090704), Ui et al. (US 5976992), and Ludviksson (US 20060255260) as evidentiary references.
Regarding Claim 16:
Guha teaches a plasma etching apparatus comprising: a plasma generating source (upper sub-chamber 502); an ionization space (space between grids 551 and 552) coupled to the plasma generating source and configured to generate ions (plasma is generated in upper sub-chamber 502); a first grid (upper grid 551) between the ionization space and the plasma generating source;
an acceleration space (lower sub-chamber 503) coupled to the ionization space and configured to deliver the ions to a substrate in the acceleration space (ions are accelerated from the upper sub-chamber to the lower sub-chamber); a substrate support (chuck 517) for supporting the substrate in the acceleration space, wherein the substrate support is configured to be biased (the electrostatic chuck used to support the substrate may be negatively biased to attract positive ions onto the substrate's surface); and a controller (a system controller may control some or all of the operations); ignite plasma of a noble gas in the plasma generating source (plasma may be generated in the upper sub chamber 502; the plasma may be generated from an inert gas such as argon); cause metastable neutral species of the plasma of the noble gas to diffuse to the ionization space (the plasma may be formed from a combination of gases such as Argon and Oxygen, which would generate a metastable species. Furthermore, a positive bias may be applied to the substrate) [Fig. 5 & 0043, 0076, 0081]; apply a negative bias to the substrate support; and accelerate the positive ions of the non-reactive gas to the substrate to etch the modified materials on the substrate (the electrostatic chuck used to support the substrate may be negatively biased to attract positive ions onto the substrate's surface and bombard the surface of the substrate in order to activate the surface for reaction) [Fig. 5 & 0069, 0076, 0102].
Guha does not specifically disclose one or more gas sources coupled to the ionization space, wherein the one or more gas sources are configured to supply an electronegative reactive gas and a non-reactive gas to the ionization space; and a controller configured with instructions for performing the following operations: introduce the electronegative reactive gas and the non-reactive gas to the ionization space from the one or more gas sources.
Ma teaches one or more gas sources (first and second gas ports 118 and 121, which feed first gas 210 and second gas 220, respectively) coupled to the ionization space (the space between grid plates 116b and 116c), wherein the one or more gas sources are configured to supply an electronegative reactive gas and a non-reactive gas to the ionization space (an inert gas can be delivered through the gas ports. Different gases may also flow through the two ports. The chemical composition of the fed gases can be chosen and controlled) [Fig. 5 & 0059-0060, 0067]; wherein the apparatus is configured to introduce the electronegative reactive gas and the non-reactive gas to the ionization space from the one or more gas sources (an inert gas can be delivered through the gas ports. Different gases may also flow through the two ports. The chemical composition of the fed gases can be chosen and controlled) [Fig. 5 & 0059-0060, 0067].
Guha and Ma are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the apparatus of Guha to further include one or more gas sources coupled to the ionization space, as in Ma, to provide further control over process uniformity [Ma - 0057, 0059]. It is noted that Guha discloses that its plasma may be generated from a combination of inert and reactive gases (inert gases such as Ar, He, Ne, Kr and Xe; reactive gases such as hydrogen, oxygen, and nitrogen. One or more of the inert gases listed may be used) [Guha - 0043].
Modified Guha does not specifically disclose extracting electrons from the plasma of the noble gas using the first grid apply a positive bias to the substrate support to ionize the electronegative reactive gas using the extracted electrons from the plasma of the noble gas and form negative ions of the electronegative reactive gas; accelerate the negative ions of the electronegative reactive gas to the substrate.
Collins teaches extracting electrons from the plasma of the noble gas using the first grid (radicals produced from the plasma in the upper chamber 100a may be extracted through grid filter 104 via bias application; plasma may be generated from a gas such as Argon), and apply a positive bias to the substrate and accelerate the negative ions of the electronegative reactive gas to the substrate to modify the substrate (a bias voltage may be applied to the pedestal 110 to selectively or alternately extract positive and/or negative ions from the plasma and accelerate those ions at desired energy levels to impact the surface of the workpiece 111 for etching, cleaning, deposition, or other materials modification. At least some electrons are also flowed to the lower chamber 100b.) [Fig. 1 & 0062-0064, 0087].
Modified Guha and Collins are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the controller of Modified Guha to have instructions for positively biasing a substrate support, as in Collins, to provide further control over substrate modification [Collins - 0063]. Chen et al. (US 20160293386) also discloses that selective control over positive and negative ion attraction can help minimize the effects of charge accumulation [Chen - 0005, 0046].
Modified Guha (Guha modified by Ma and Collins) does not specifically disclose to accelerate the negative ions of the electronegative gas to the substrate when the plasma is ignited, and to accelerate the positive ions of the non-reactive gas to the substrate as the plasma is quenched.
Although Wilson does not specifically disclose “to accelerate the negative ions of the electronegative gas to the substrate when the plasma is ignited, and to accelerate the positive ions of the non-reactive gas to the substrate as the plasma is quenched,” Wilson does disclose that frequency and duration of bias voltage pulses is a result effective variable. Specifically the shape, frequency, amplitude and duration of voltage pulses can be adjusted depending on the etching performance [0040]. Modified Guha and Wilson are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to find an optimum timing for the biases to obtain a desired etching performance (therefore, plasma can be quenched at any desired point in time, such as prior to support biasing). It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. See MPEP 2144.05. It is also noted that being able to adjust a frequency or duration of bias pulses would also mean that the timing of those pulses can be adjusted.
Modified Guha (Guha modified by Ma, Collins, and Wilson) does not specifically disclose quenching the plasma.
Fung teaches quench the plasma of the noble in the plasma generating source (RF power supplied for generating plasma is supplied in duty cycles, wherein there are on and off periods) [Fig. 12A, 12B& 0069-0070].
Modified Guha and Fung are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the apparatus of Guha to include periods of time where plasma is quenched, as in Fung, to provide control over etchant concentrations [Fung - 0041, 0053, 0063, 0094]. Accordingly, Fung also discloses that plasma duty cycle is a result effective variable. Specifically, the on and off periods for plasma generation can be controlled to control etchant concentration. As such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to find an optimum duty cycle to obtain a desired etching profile. It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. See MPEP 2144.05.
PNG
media_image2.png
568
679
media_image2.png
Greyscale
It is also noted that the controller limitations of claim 16 that are boxed (as shown in the annotated drawing above) are what the examiner considers structural programming, and as such, would have structural weight in the apparatus (i.e., the process steps that are positively recited). The portions of the controller limitations that are not boxed are considered intended results of steps that are positively recited. The court noted that a "‘whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.’" Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)). As such, the combination of references need only be capable of performing the intended results.
Regarding “to cause metastable neutral species of the plasma of the noble gas to diffuse to the ionization space,” the examiner would like to note that the instant application does not provide specific support for the code of the program of the controller to directly cause the neutral species to diffuse. Rather, the controller discloses that through negative biasing of the support, the neutral species may be extracted [IA – 0050, 0056]. Guha discloses applying a negative bias to the electrostatic chuck [Guha - 0076]. Guha also discloses that plasma may be generated in the upper sub chamber 502; the plasma may be generated from an inert gas such as argon, or a combination of gases such as argon and oxygen [Guha – 0043]. Ma discloses feeding a combination of gases between grids (the gases can be chosen and controlled, and since Guha discloses that gases such as oxygen and argon can be used in its apparatus, feeding oxygen/argon between grids would be obvious) [Ma - 0059-0060, 0067]. As such, the combination of references discloses the positively recited step of negatively biasing a support. Therefore, since the combination of references is performing the same steps as the instant application, the intended result would occur.
Regarding “to ionize the electronegative reactive gas using the extracted electrons from the plasma of the noble gas and form negative ions of the electronegative reactive gas; to ionize the non-reactive gas using the metastable neutral species from the plasma of the noble gas and form positive ions of the non-reactive gas,” the examiner would like to note that the instant application does not provide specific support for the code of the program of the controller to directly ionize the respective gases. Rather, the controller discloses that through biasing of the support, respective species may be extracted through the grids such that reactions occur that result in the formation of the respective ions [IA – 0048-0050, 0056]. Collins discloses selective biasing of the substrate support, therefore negative and positive particles would be extracted from the plasma through respective grid plates [Collins – 0063, 0087]. Ma discloses feeding a combination of gases between grids (the gases can be chosen and controlled, and since Guha discloses that gases such as oxygen and argon can be used in its apparatus, feeding oxygen/argon between grids would be obvious) [Ma - 0059-0060, 0067]. Since the combination of references discloses a noble gas plasma that is quenched (of which, electrons and metastable species would be present), the application of a support bias would extract those electrons and metastable species and cause those electrons/metastable species to interact with other substances along the way (see the evidentiary references listed below). Therefore, since the combination of references is performing the same steps as the instant application, the intended result would occur.
Furthermore, Class et al. (US 4422896) discloses that the electron-molecule collisions in a plasma convert molecular oxygen to atomic oxygen, as well as positive and negative oxygen ions [Col. 2 lines 30-40]. Ide (US 20060090704) discloses that in oxygen plasma, the electrons generated by dissociation are also consumed in the production of negative ions [Ide - 0065 - 0069]. Ui et al. (US 5976992) discloses that when a rare gas such as argon is added to oxygen plasma, part of the rare gas is turned into a metastable excited state, which then acts upon oxygen atoms to ionize through penning ionization [Ui - Col. 12 lines 25-37]. Ludviksson (US 20060255260) also discloses that a gas such as helium can be excited to collide with neutral molecules to produce positive ions [Ludviksson - 0032-0037].
In summary, the instant application does not provide support for the programming of the controller specifically to form the respective ions, but rather, it has support for controlling biasing of the support, which in turn causes ionization via extraction of species through the grids [IA – 0048-0050, 0056]. The combination of references does disclose biasing of the support and noble gas plasma generation and would therefore disclose the formation of the respective species. So while the combination of references may not explicitly disclose the formation of the respective species, since the combination of references discloses all of the steps that are positively recited (biasing of the support, generation of plasma from a noble gas, feeding an electronegative gas), the intended results would occur.
Regarding Claim 17:
Modified Guha (Guha modified by Ma and Collins) does not specifically disclose wherein the positive bias is between about 0.5 V and about 10 V, and wherein the negative bias is between about -50 kV and about -1 kV.
Although Wilson does not specifically disclose “wherein the positive bias is between about 0.5 V and about 10 V, and wherein the negative bias is between about -50 kV and about -1 kV,” Wilson does disclose that voltage amplitude is a result effective variable. Specifically, the shape, frequency, amplitude and duration of voltage pulses can be adjusted depending on the etching performance [Wilson - 0040]. Modified Guha and Wilson are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to find an optimum amplitude for the biases to obtain a desired etching performance. It has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. See MPEP 2144.05.
Regarding Claim 18:
Guha teaches wherein the first grid is configured to be biased and the second grid is configured to be biased (power supplies 557 and 567 can supply biases to upper grid 551 and lower grid 552, respectively) [Fig. 5 & 0081, 0089].
Furthermore, the limitations “wherein a pressure in the ionization space is greater than a pressure in the acceleration space” are merely intended use and are given weight to the extent that the prior art is capable of performing the intended use. A claim containing a “recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus” if the prior art apparatus teaches all the structural limitations of the claim. Ex parte Masham, 2 USPQ2d 1647 (Bd. Pat. App. & Inter. 1987). It is noted that the pressure in the sub chambers of Guha are set to be different, therefore the apparatus would be capable of setting the pressure of the space between grids 551 and 552 to be higher than the pressure of the lower-sub chamber.
Regarding Claim 19:
Guha teaches wherein the plasma generating source is an inductively coupled plasma (ICP) reactor (plasma is generated in upper sub-chamber 502 via coil 533) [Fig. 5 & 0091, 0093].
Regarding Claim 20:
Modified Guha (Guha modified by Ma) does not specifically disclose wherein the controller is further configured with instructions for performing the following operation: repeat and alternate operations of applying the positive bias to the substrate.
Collins teaches wherein the controller is further configured with instructions for performing the following operation: repeat and alternate operations of applying the positive bias to the substrate support (the bias voltage supplied to the support pedestal 110 is a waveform of low repetition frequency; bias that is applied may alternate between attracting positive or negative ions) [Fig. 1 & 0063].
Modified Guha and Collins are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to modify the controller of Modified Guha to have instructions for positively biasing a substrate support, as in Collins, to provide further control over substrate modification [Collins - 0063]. Chen et al. (US 20160293386) also discloses that selective control over positive and negative ion attraction can help minimize the effects of charge accumulation [Chen - 0005, 0046].
Modified Guha (Guha modified by Ma and Collins) does not specifically disclose applying the positive bias to the substrate support when the plasma is ignited and applying the negative bias to the substrate support when the plasma is quenched.
Although Wilson does not specifically disclose “applying the positive bias to the substrate support when the plasma is ignited and applying the negative bias to the substrate support when the plasma is quenched,” Wilson does disclose that frequency and duration of bias voltage pulses is a result effective variable. Specifically the shape, frequency, amplitude and duration of voltage pulses can be adjusted depending on the etching performance [0040]. Modified Guha and Wilson are analogous inventions in the field of plasma etching apparatuses. It would have been obvious to one of ordinary skill in the art to find an optimum timing for the biases to obtain a desired etching performance. It