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 .
Response to Amendment
Applicant’s amendment filed 01/14/2026 is acknowledged and has been accepted by the examiner. Claims 1-22 are pending.
Response to Arguments
Applicant’s arguments with respect to claims 1-22 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Claim Rejections - 35 USC § 103
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 (i.e., changing from AIA to pre-AIA ) 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.
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.
Claims 1, 2, 4, and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Chen (US20200373210A1), Chism (US20070097370A1), Meta (US9749044B1) as evidenced by RP Photonics (R. Paschotta, article on "Photodiodes" in the RP Photonics Encyclopedia, , https://doi.org/10.61835/8jq Available as early as 2006. Screenshot taken from Wayback Machine, March 9, 2022), and Lee (US20160126068A1).
Regarding claim 1, Mihaylov teaches an optical emission spectroscopy (OES) detection device comprising:
an optical collector (110, Fig. 3A) configured to be optically coupled to a plasma through an optical window (116, Fig. 2B) of a chamber of a plasma processing apparatus (plasma processing chamber, 104; paragraph [0007]), the plasma being generated in the chamber using a sequence of radio frequency (RF) source power (SP) pulses (paragraph [0023] discloses the plasma ignition source may be an RF source), the optical collector receiving an optical signal from the plasma (Fig. 1 shows the light collector (110) receiving an optical signal from the plasma processing chamber);
a wavelength filter optically coupled to the optical collector (310, Fig. 3A; paragraph [0041] discloses the photodiode may include an optical filter) and configured to
automatically adjust a passband of the wavelength filter to include a selected wavelength in response to receiving a wavelength selection signal (paragraphs [0041] and [0043] both disclose optical filters used to filter a specific wavelength depending on a selected wavelength), and
allow a filtered portion of the optical signal to pass through while excluding a remaining portion of the optical signal, the filtered portion comprising the selected wavelength (paragraphs [0041] and [0043]);
a photodiode optically coupled to the adjustable wavelength filter (Fig. 3A shows an optical filter (310) coupled to the light detector (112)) and configured to generate an OES measurement in response to detecting the filtered portion of the optical signal (Fig. 3A - light goes through optical filter before photodiode).
Mihaylov fails to teach the wavelength filter being an adjustable wavelength filter, the photodiode being configured to generate an electric current, the photodiode having an active area diameter less than about one millimeter; and
a timing circuit configured to receive a synchronization signal from a power control path of the plasma processing apparatus and use the synchronization signal to ensure locked-in synchrony with pulsing of the plasma by causing the OES detection device to collect a series of OES measurements from the photodiode during only a selected portion of each power cycle of the sequence of RF SP pulses.
However, in the same field of endeavor of OES detection devices, Chen teaches an adjustable wavelength filter for selecting different wavelengths of the transmitted optical signal (tunable wavelength filter - paragraph [0012]).
Chen discloses the use of a tunable wavelength filter allows for a wide range of wavelengths and applications (paragraph [0014]). Thus, it would be obvious to a person having ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov with the adjustable wavelength filter taught in Chen as it allows for a wide range of wavelengths and applications.
Mihaylov as modified by Chen fails to teach the photodiode being configured to generate an electric current, the photodiode having an active area diameter less than about one millimeter; and
a timing circuit configured to receive a synchronization signal from a power control path of the plasma processing apparatus and use the synchronization signal to ensure locked-in synchrony with pulsing of the plasma by causing the OES detection device to collect a series of OES measurements from the photodiode during only a selected portion of each power cycle of the sequence of RF SP pulses.
However, in the same field of endeavor of optical detection systems, Chism teaches a device which sends light to a photodiode and converts the signal to an electric current (paragraph [0045]).
Chism discloses that including the electric current generation in the photodiode rather than an additional circuit is a way to avoid adding unnecessary bulk (paragraph [0003]). Thus, it would be obvious to a person having ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov as modified by Chen with the photodiode configured to generate an electric current taught in Chism to avoid adding unnecessary bulk.
Mihaylov as modified by Chism and Chen fails to teach the photodiode having an active area diameter less than about one millimeter; and
a timing circuit configured to receive a synchronization signal from a power control path of the plasma processing apparatus and use the synchronization signal to ensure locked-in synchrony with pulsing of the plasma by causing the OES detection device to collect a series of OES measurements from the photodiode during only a selected portion of each power cycle of the sequence of RF SP pulses.
However, in the same field of endeavor of photodetectors used for optical measurements, Meta teaches a photodiode have an active region with a diameter of one millimeter or less (column 19, lines 1-2).
RP Photonics teaches that a larger active area decreases detection bandwidth, which decreases responsivity (2nd paragraph). Therefore, a smaller active area of a photodiode would lead to a better responsivity of the photodiode. Thus, a person of ordinary skill in the art prior to the effective filing date would find it obvious to combine the device of Mihaylov as modified by Chen and Chism with the photodiode diameter taught in Meta in order to have a better responsivity.
Mihaylov as modified by Chism, Chen, and Meta fails to teach a timing circuit configured to receive a synchronization signal from a power control path of the plasma processing apparatus and use the synchronization signal to ensure locked-in synchrony with pulsing of the plasma by causing the OES detection device to collect a series of OES measurements from the photodiode during only a selected portion of each power cycle of the sequence of RF SP pulses.
However, in the same field of endeavor of optical emission sensors, Lee teaching a digitizer (40, Fig. 1) and analyzer (50, Fig. 1) configured to receive a synchronization signal from a power control path (shown as 'PS' sent from 'pulse controller' 21 to the digitizer 40 in Fig. 1; paragraph [0061] further describes this), and also collects certain measurements from the sensor during the pulse-on or pulse-off period (paragraph [0014]). The examiner is interpreting the digitizer and analyzer to be analogous to the timing circuit.
Mihaylov discloses the plasma processing chamber disclosed may be used for semiconductor etching (paragraphs [0003], [0023], [0024]). Lee discloses that by synchronizing the measurement signal with pulse control, etch end point detection is enabled (paragraph [0025]), which enables precise etching and wafer yield (paragraphs [0090] and [0091]). Thus, it would be obvious for a person of ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov as modified by Chen, Chism, and Meta with the pulse-measurement synchronization taught in Lee in order to enable precise semiconductor etching. 20170084433
Regarding claim 2, Mihaylov as modified by Chen, Chism, Meta and Lee teaches the invention as explained above in claim 1, and further teaches wherein rise and fall times of the electric current (Chism: paragraph [0045]) generated by the photodiode are less than about a nanosecond (Mihaylov: paragraph [0034]).
As discussed above in claim 1, it would be obvious for a person having ordinary skill in the art prior to the effective filing date to combine the photodiode of Mihaylov as modified by Chen, Chism, Meta and Lee with the photodiode configured to generate an electric current taught in Chism to avoid adding unnecessary bulk.
Regarding claim 4, Mihaylov as modified by Chen, Chism, Meta and Lee teaches the invention as explained above in claim 1, and further teaches the adjustable wavelength filter comprises a Fabry-Perot interferometer with a tunable air gap (Chen: paragraph [0038]).
Chen discloses a Fabry-Perot cavity is desirable to use as a wavelength filter as it is a widely used and commercially available device (paragraph [0038]), therefore making it easily accessible to one of ordinary skill in the art. Thus, it would be obvious for a person of ordinary skill in the art to combine the device of Mihaylov as modified by Chen, Chism, RP Photonics and Lee with the Fabry-Perot wavelength filter taught in Chen as it is easily accessible.
Regarding claim 6, Mihaylov as modified by Chen, Chism, Meta and Lee teaches the invention as explained above in claim 1, and further teaches one or more additional optical paths (Mihaylov: paragraph [0030] discloses the collector has multiple paths), each comprising:
an additional adjustable wavelength filter optically coupled to the optical collector (Mihaylov: paragraph [0043] discloses additional optical filters in all channels) and configured to automatically adjust a passband of the additional adjustable wavelength filter to include an additional selected wavelength in response to receiving an additional wavelength selection signal (Chen: paragraph [0038]), and
allow an additional filtered portion of the optical signal to pass through while excluding a remaining portion of the optical signal, the additional filtered portion comprising the additional selected wavelength paragraph [0043] discloses the filter may be used to block a portion of the optical signal, while allowing a selected wavelength to pass through); and
an additional photodiode (Mihaylov: paragraph [0042] discloses there may be one or more photodiodes) optically coupled to the adjustable wavelength filter (Chen: paragraph [0012]) and configured to generate an electric current (Chism: paragraph [0045]) as an OES measurement in response to detecting the additional filtered portion of the optical signal, the additional photodiode having an active area diameter less than about one millimeter (Meta: column 19, lines 1-2).
As explained above in claim 1, it would be obvious for a person of ordinary skill in the art prior to the effective filing date to combine the wavelength filter of Mihaylov with the adjustable wavelength filter taught in Chen in order to have a wider range of applications, to combine the photodiode of Mihaylov with the photodiode configured to generate an electric current taught in Chism in order to avoid unnecessary bulk, and the photodiode of Meta having an active area diameter of less than 1 millimeter in order to improve detection bandwidth and increase responsivity as taught by RP Photonics.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Chen (US20200373210A1), Chism (US20070097370A1), Meta (US9749044B1) as evidenced by RP Photonics (R. Paschotta, article on "Photodiodes" in the RP Photonics Encyclopedia, https://doi.org/10.61835/8jq Available as early as 2006. Screenshot taken from Wayback Machine, March 9, 2022), and Lee (US20160126068A1) as applied to claim 1 above, and further in view of Mahoney (US20050034811A1).
Regarding claim 3, Mihaylov as modified by Chen, Chism, Meta, and Lee teaches the invention as explained above in claim 1, and further teaches the timing circuit is electrically coupled to the photodiode (Lee: Fig. 1 depicts the digitizer and analyzer coupled in some way to the optical emission sensor; paragraph [0059] discloses the sensor may include a photodiode).
As discussed above in claim 1, it would be obvious for a person of ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov as modified by Chen, Chism, Meta and Lee with the pulse-measurement synchronization taught in Lee in order to enable precise semiconductor etching.
Mihaylov as modified by Chen, Chism, Meta and Lee fails to teach the timing circuit configured to generate a setup delay in response to receiving the synchronization signal from the plasma processing apparatus,
generate a clock signal having a frequency greater than 1 kHz, and
cause the OES detection device to collect the series of OES measurements from the photodiode after the setup delay by switching the photodiode off and on according to the clock signal during the selected portion of each power cycle.
However, in the same field of endeavor of optical monitoring of plasma processing, Mahoney teaches a device which synchronizes data acquisition with plasma pulses (paragraph [0055]) through a delay and holding signal, where the frequency is greater than 1 kHz (paragraph [0056] discloses the pulsing frequency is in the range of 100 Hz to 10 kHz, while the sensor frequency is between 1 and 20 kHz, and the synchronization is done by delaying and holding the sensor signal to enable synchronous sampling). Further, Mahoney teaches powering the sensors on and off to synchronize the triggering of the sensors to take measurements (paragraph [0058]).
Mahoney discloses that the method of synchronization used allows for plasma variations caused by the plasma pulses to be accounted for (paragraph [0055]) and avoids noise in the sensor readings, making the readings more accurate (paragraph [0056]). Thus, it would be obvious for a person of ordinary skill in the art to combine the device of Mihaylov as modified by Chen, Chism, Meta and Lee with the measurement synchronization taught in Mahoney in order to take more accurate measurements.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Chen (US20200373210A1), Chism (US20070097370A1), Meta (US9749044B1) as evidenced by RP Photonics (R. Paschotta, article on "Photodiodes" in the RP Photonics Encyclopedia, , https://doi.org/10.61835/8jq Available as early as 2006. Screenshot taken from Wayback Machine, March 9, 2022), and Lee (US20160126068A1) as applied to claim 1 above, and further in view of Lam (US20170084433A1).
Regarding claim 5, Mihaylov in view of Chen, Chism, Meta, and Lee teach the invention as explained above in claim 1, and further teaches the adjustable wavelength filter (Chen: paragraph [0012]) and a fiber optic optically coupled to the photodiode and configured to transmit the filtered optical signal to the photodiode (Mihaylov: paragraph [0037]).
As discussed above in claim 1, it would be obvious to a person having ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov as modified by Chen, Chism, Meta and Lee with the adjustable wavelength filter taught in Chen as it allows for a wide range of wavelengths and applications.
Mihaylov in view of Chen, Chism, Meta and Lee fails to teach a collimator optically coupled between the optical collector and the adjustable wavelength filter, the collimator being configured to form a parallel beam from the optical signal; and
a focusing lens optically coupled between the adjustable wavelength filter and the fiber optic, the focusing lens being configured to focus the filtered optical signal on an input of the fiber optic.
However, in the same field of endeavor of optical emission spectroscopy, Lam teaches a collimator (228, Fig. 2; any collimator can be configured to form a parallel beam) that is coupled to an optical collector (220, Fig. 2), and has focusing optics to focus the filtered optical signal on an input of a fiber optic coupler (paragraph [0053]). Lam does not teach the focusing optics between a wavelength filter and the fiber optic, however the operation of the device would not be modified by the placement of the focusing lens before or after the wavelength filter, as the optical signal would be filtered either way.
The collimator of Lam is used as a coupler which collects the optical signal (paragraph [0053]), ensuring the signal reaches the optical detector. Further, Lam discloses the focusing optics allow the signal to match the acceptance of the fiber, ensuring the signal is carried and reaches the detector (paragraph [0053]). Thus, it would be obvious for a person having ordinary skill in the art to combine the device of Mihaylov as modified by Chen, Chism, Meta and Lee with the collimator and focusing optics taught in Lam to ensure the signal is carried to the optical collector.
Claims 7, 8, 9, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Lee (US20160126068A1), Chen (US20200373210A1) and Mahoney (US20050034811A1).
Regarding claim 7, Mihaylov teaches a pulsed plasma optical emission spectroscopy (OES) system (see claim 15 and paragraph [0027] which discloses the system may also be used for OES measurements) comprising:
a pulsed plasma processing apparatus (100, Fig. 1) comprising a plasma processing chamber (104, Fig. 1) comprising an optical window (116, Fig. 1), and
a source power (SP) coupling element configured to generate a plasma contained by the plasma processing chamber (paragraph [0023] discloses a source power element);
an OES detection device (112, Fig. 1) optically coupled to the plasma through the optical window of the plasma processing chamber (paragraph [0027]) and comprising a wavelength filter (paragraph [0041]) and a photodetector (paragraph [0041] also discloses the detector may be a photodiode); and
the series of OES measurements comprising a temporal resolution less than a millisecond so that multiple OES measurements of the series are collected for each RF SP pulse of the sequence (paragraph [0033] teaches the detector is equipped to handle signals in the microsecond range).
Mihaylov fails to teach a power control path comprising an SP control path electrically coupled to the SP coupling element and configured to supply a sequence of radio frequency (RF)SP pulses to the SP coupling element to generate the plasma;
the wavelength filter being an adjustable wavelength filter;
a timing circuit configured to receive a synchronization signal from the power control path and use the synchronization signal to ensure locked-in synchrony with pulsing of the plasma by generating a setup delay; and
a control and data acquisition circuit electrically coupled to the adjustable wavelength filter and the photodetector, the control and data acquisition circuit being configured to adjust a passband of the adjustable wavelength filter to a selected wavelength using a wavelength selection signal, and
cause the photodetector to collect a series of OES measurements of the plasma from the OES detection device during only a selected portion of each power cycle of the sequence of RF SP pulses using the setup delay from the timing circuit.
However, Lee teaches a power control path (see lines connecting pulse controller to pulse RF generators, Fig. 1), comprising an SP control path coupled to the source power element (23a, 23b, 23c, Fig. 1) which supplies a sequence of RF pulses to generate plasma (paragraph [0046]). Lee also teaches a timing circuit (digitizer 40, Fig. 1) which receives a synchronization signal from the power control path (see black line labeled 'PS', Fig. 1) to ensure synchrony with the plasma pulsing (paragraph [0061]).
Mihaylov discloses the plasma processing chamber disclosed may be used for semiconductor etching (paragraphs [0003], [0023], [0024]). Lee discloses that by synchronizing the measurement signal with pulse control, etch end point detection is enabled (paragraph [0025]), which enables precise etching and wafer yield (paragraphs [0090] and [0091]). Thus, it would be obvious for a person of ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov with the pulse synchronization taught in Lee in order to enable precise semiconductor etching.
Mihaylov as modified by Lee fails to teach the wavelength filter being an adjustable wavelength filter;
generating a setup delay; and
a control and data acquisition circuit electrically coupled to the adjustable wavelength filter and the photodetector, the control and data acquisition circuit being configured to adjust a passband of the adjustable wavelength filter to a selected wavelength using a wavelength selection signal, and
cause the photodetector to collect a series of OES measurements of the plasma from the OES detection device during only a selected portion of each power cycle of the sequence of RF SP pulses using the setup delay from the timing circuit.
However, Chen teaches a tunable wavelength filter for selecting different wavelengths of the transmitted optical signal (paragraph [0012]), and a controller which is coupled to the adjustable filter and selects a wavelength range in response to a selection signal (paragraph [0038]).
Chen discloses the use of a tunable wavelength filter and controller allows for a wide range of wavelengths and applications (paragraph [0014]). Thus, it would be obvious to a person having ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov as modified by Lee with the adjustable wavelength filter taught in Chen as it allows for a wide range of wavelengths and applications.
Mihaylov as modified by Lee and Chen fails to teach generating a setup delay; and
causing the photodetector to collect a series of OES measurements of the plasma from the OES detection device during only a selected portion of each power cycle of the sequence of RF SP pulses using the setup delay from the timing circuit.
However, Mahoney teaches a device which synchronizes data acquisition with plasma pulses (paragraph [0055]) through a delay and holding signal (paragraph [0056]), and further powering the sensors on and off to synchronize the triggering of the sensors to take measurements (paragraph [0058]).
Mahoney discloses that the method of synchronization used allows for plasma variations caused by the plasma pulses to be accounted for (paragraph [0055]) and avoids noise in the sensor readings, making the readings more accurate (paragraph [0056]). Thus, it would be obvious for a person of ordinary skill in the art to combine the device of Mihaylov as modified by Lee and Chen with the measurement synchronization taught in Mahoney in order to take more accurate measurements.
Regarding claim 8, Mihaylov in view of Lee, Chen and Mahoney teaches the invention as explained above in claim 7, the control and data acquisition circuit is further configured to set an integration time of the photodetector to between about 2 microseconds and about 100 microseconds (Mihaylov: paragraph [0026] teaches the photodetector is controlled by a controller (analogous to the control and data acquisition circuit); 114, Fig. 1; paragraphs [0033]-[0034] teach the photodetector can handle pulses in the nanosecond to microsecond range).
Regarding claim 9, Mihaylov in view of Lee, Chen and Mahoney teaches the invention as explained above in claim 7, and further teaches wherein the timing circuit (Lee: 40, Fig. 1) is electrically coupled to the control and data acquisition circuit (Lee: 50, Fig. 1; paragraph [0063] discloses the analyzer 50 may be a controller), the timing circuit being configured to generate a clock signal having a frequency greater than 1 kHz in response to receiving the synchronization signal corresponding to the sequence of RF SP pulses (Mahoney: paragraph [0056]), and
wherein the control and data acquisition circuit is further configured to cause the OES detection device to collect the series of OES measurements after the setup delay using the photodetector by switching the photodetector off and on according to the clock signal during the selected portion of each power cycle (Mahoney: paragraph [0058]).
As explained above in claim 7, it would be obvious for a person of ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov as modified by Lee, Chen and Mahoney with the timing circuit taught in Lee in order to enable precise semiconductor etching.
As explained above in claim 7, it would be obvious for a person of ordinary skill in the art to combine the device of Mihaylov as modified by Lee, Chen and Mahoney with the measurement synchronization taught in Mahoney in order to take more accurate measurements.
Regarding claim 10, Mihaylov in view of Lee, Chen and Mahoney teach the invention as explained above in claim 9, and further teaches the control and data acquisition circuit is further configured to use the synchronization signal (Lee: paragraph [0061] describes the synchronization signal) to cause the OES detection device to collect the series of OES measurements during the selected portion of each power cycle of the sequence of RF SP pulses (Lee: paragraph [0014] discloses certain measurements during the pulse sequence are collected).
As explained above in claim 7, it would be obvious for a person of ordinary skill in the art prior to the effective filing date to combine the device of Mihaylov as modified by Lee, Chen and Mahoney with the synchronization signal taught in Lee in order to enable precise semiconductor etching.
Claims 11 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Lee (US20160126068A1), Chen (US20200373210A1) and Mahoney (US20050034811A1) as applied above to claims 7 and 9, further in view of Lam (US20170084433A1).
Regarding claim 11, Mihaylov in view of Lee, Chen and Mahoney teach the invention as explained above in claim 9, and further teaches supplying a sequence of BP pulses to a substrate holder of the pulsed plasma processing apparatus disposed within the plasma processing chamber and configured to support a substrate (Mahoney: paragraphs [0018] and [0035] disclose a bias power may be applied to the wafer holder), and the control and data acquisition circuit is further configured to use the synchronization signal to cause the OES detection device to collect the series of OES measurements during a selected portion of each power cycle of the sequence of BP pulses (Mahoney: paragraph [0058] discloses the collection of measurements may be synchronized with the power cycle due to anything between the power supply and plasma source, which may also include a bias voltage applied to the wafer (paragraphs [0018], [0035]). Paragraph [0058] further discloses the collection may be synchronized with the power cycle and only take measurements during an on or off period).
Mahoney discloses that voltage biases applied to the wafer holder are often required in various processing methods (paragraph [0035]), therefore making it necessary to account for the voltage bias as it influences measurements (see Fig. 4b). Thus, a person of ordinary skill in the art would find it obvious to combine the method of Mihaylov as modified by Lee, Chen and Mahoney with the ability to synchronize with the wafer bias taught in Mahoney in order to account for the influence a wafer bias has on measurements.
Mihaylov in view of Lee, Chen and Mahoney fails to explicitly teach a bias power (BP) control path of the power control path configured to supply a sequence of BP pulses to a substrate holder of the pulsed plasma processing apparatus disposed within the plasma processing chamber and configured to support a substrate.
However, Lam teaches an embodiment that includes a bias voltage source (paragraph [0069], analogous to a bias power control) and a substrate holder (baseplate, 110, Fig. 1) that may be fed voltage (paragraph [0047]).
Mihaylov discloses the plasma processing chamber disclosed may be used for semiconductor etching (paragraphs [0003], [0023], [0024]). Lam uses the bias voltage for etching (paragraph [0069]), as it is known in the art to ideal for etching. It would be obvious to one of ordinary skill in the art prior to the effective filing date to combine the system of Mihaylov as modified by Lee, Chen and Mahoney with the biased power supply taught in Lam as bias voltages are ideal for etching.
Regarding claim 12, Mihaylov as modified by Lee, Chen and Mahoney teaches the invention as explained above in claim 7, and further teaches the timing circuit is electrically coupled to the control and data acquisition circuit, the timing circuit being configured to trigger the control and data acquisition circuit to cause the photodetector to collect the series of OES measurements in response to receiving the synchronization signal from at least one of the SP control path and the BP control path (Mahoney: paragraphs [0056] and [0058] disclose the measurements may be synchronized to any power source, including a bias power);
and wherein the control and data acquisition circuit is further configured to process, amplify, and digitize the series of OES measurements for output to a computing system (Lee: paragraph [0063]).
As explained above in claim 7, it would be obvious for a person of ordinary skill in the art to combine the device of Mihaylov as modified by Lee, Chen and Mahoney with the measurement synchronization taught in Mahoney in order to take more accurate measurements.
Lee discloses that processing the measurements by a controller enables a high time resolution and accurate analysis of the plasma pulses (paragraph [0063]). Thus, it would be obvious for one of ordinary skill in the art to combine the device of Mihaylov as modified by Lee, Chen and Mahoney with the processing of measurements taught by Lee in order to accurately analyzed the plasma pulses.
Mihaylov in view of Lee, Chen and Mahoney fails to explicitly teach a bias power (BP) control path of the power control path configured to supply a sequence of BP pulses to a substrate holder of the pulsed plasma processing apparatus disposed within the plasma processing chamber and configured to support a substrate.
However, Lam teaches an embodiment that includes a bias voltage source (paragraph [0069] – analogous to the bias power control) and a substrate holder (baseplate, 110, Fig. 1) that may be fed voltage (paragraph [0047]).
Mihaylov discloses the plasma processing chamber disclosed may be used for semiconductor etching (paragraphs [0003], [0023], [0024]). Lam uses the bias voltage for etching (paragraph [0069]), as it is known in the art to ideal for etching. It would be obvious to one of ordinary skill in the art prior to the effective filing date to combine the system of Mihaylov as modified by Lee, Chen and Mahoney with the biased power supply taught in Lam as bias voltages are ideal for etching.
Claims 13 rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Lee (US20160126068A1), Chen (US20200373210A1) and Mahoney (US20050034811A1) as applied above to claim 7, further in view of Meta (US9749044B1) as evidenced by RP Photonics (R. Paschotta, article on "Photodiodes" in the RP Photonics Encyclopedia, https://doi.org/10.61835/8jq Available as early as 2006. Screenshot taken from Wayback Machine, March 9, 2022).
Regarding claim 13, Mihaylov as modified by Lee, Chen and Mahoney teaches the invention as explained above in claim 7, and further teaches the adjustable wavelength filter is a Fabry-Perot interferometer with a tunable air gap (Chen: paragraph [0038]).
Chen discloses a Fabry-Perot cavity is desirable to use as a wavelength filter as it is a widely used and commercially available device (paragraph [0038]), therefore making it easily accessible to one of ordinary skill in the art. Thus, it would be obvious for a person of ordinary skill in the art to combine the device of Mihaylov as modified by Lee, Chen, and Mahoney with the Fabry-Perot wavelength filter taught in Chen as it is easily accessible.
Mihaylov as modified by Lee, Chen and Mahoney fails to teach the photodetector is a photodiode having an active area diameter less than about one millimeter.
However, in the same field of endeavor of photodetectors used for optical measurements, Meta teaches a photodiode have an active region with a diameter of one millimeter or less (column 19, lines 1-2).
RP Photonics teaches that a larger active area decreases detection bandwidth, which decreases responsivity (2nd paragraph). Therefore, a smaller active area of a photodiode would lead to a better responsivity of the photodiode. Thus, a person of ordinary skill in the art prior to the effective filing date would find it obvious to combine the device of Mihaylov as modified by Lee, Chen and Mahoney with the photodiode diameter taught in Meta in order to have a better responsivity.
Claims 14, 17-19 are rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Chen (US20200373210A1) and Lee (US20160126068A1).
Regarding claim 14, Mihaylov teaches a method (title; paragraph [0005]) of collecting optical emission spectroscopy (OES) data of a pulsed plasma process (see claim 15 and paragraph [0027] which discloses OES measurements are also taken), the method comprising:
selecting a first wavelength for a wavelength filter of an OES detection device (paragraph [0041] discloses a photodiode may include an optical filter configured for a specific wavelength) optically coupled to a plasma through an optical window of a plasma processing chamber of a plasma processing apparatus (paragraph [0027]), the plasma processing chamber being configured to contain the plasma for the pulsed plasma process (paragraph [0024] discloses a pulsed plasma may be used); and collecting measurements comprising a temporal resolution less than a millisecond so that multiple OES measurements of the series are collected for each RF SP pulse of the sequence (paragraph [0033] teaches the detector is equipped to handle signals in the microsecond range).
Mihaylov fails to teach the wavelength filter is adjustable, or collecting a series of OES measurements of the plasma through the adjustable wavelength filter in response to a timing circuit of the OES detection device receiving a synchronization signal from a power control path of the plasma processing apparatus configured to generate a sequence of radio frequency (RF)source power (SP) pulses applied to the plasma processing chamber to generate the plasma, the series of OES measurements being collected during only a selected portion of each power cycle of the sequence of RE SP pulses.
However, Chen teaches a tunable wavelength filter for selecting different wavelengths of the transmitted optical signal (paragraph [0012]).
Chen discloses the use of a tunable wavelength filter allows for a wide range of wavelengths and applications (paragraph [0014]). Thus, it would be obvious to a person having ordinary skill in the art prior to the effective filing date to combine the method of Mihaylov with the adjustable wavelength filter taught in Chen as it allows for a wide range of wavelengths and applications.
Mihaylov as modified by Chen fails to teach collecting a series of OES measurements of the plasma through the adjustable wavelength filter in response to a timing circuit of the OES detection device receiving a synchronization signal from a power control path of the plasma processing apparatus configured to generate a sequence of radio frequency (RF)source power (SP) pulses applied to the plasma processing chamber to generate the plasma, the series of OES measurements being collected during only a selected portion of each power cycle of the sequence of RE SP pulses.
However, Lee discloses collecting measurement through a wavelength filter (see the path of the optical signal going from detection window 31 to optical filter 35 in Fig. 1A), and a timing circuit receiving a synchronization signal from a power control path (paragraph [0061]), and collecting certain measurements taken during the pulse-on or pulse-off period (paragraph [0014]; paragraph [0063]). Further, Lee also uses radio frequency pulse generators to create the plasma pulses (see 23a, 23b, 23c in Fig. 1A).
Mihaylov discloses the plasma processing chamber disclosed may be used for semiconductor etching (paragraphs [0003], [0023], [0024]). Lee discloses that by synchronizing the measurement signal with pulse control, etch end point detection is enabled (paragraph [0025]), which enables precise etching and wafer yield (paragraphs [0090] and [0091]). Further, RF plasma generators are one of the most common ways of generating a plasma and have the advantage of minimizing damage to delicate substrates and are therefore ideal for precision applications. Thus, a person having ordinary skill in the art prior to the effective filing date would find it obvious to combine the method of Mihaylov as modified by Chen with the synchronization method taught in Lee in order to enable precise end point detecting and etching.
Regarding claim 17, Mihaylov in view of Chen and Lee teaches the invention as explained above in claim 14, and further teaches continuously selecting wavelengths for the adjustable wavelength filter from a range of wavelengths including the first wavelength while collecting the series of OES measurements of the plasma through the adjustable wavelength filter (Chen: paragraph [0039]).
Chen discloses a continuous sweeping of the wavelength ranges increases the rate of measurement (paragraph [0039]). Thus, a person having ordinary skill in the art would find it obvious to combine the method of Mihaylov as modified by Chen and Lee with the continuous wavelength sweep taught in Chen in order to increase the rate of measurements.
Regarding claim 18, Mihaylov in view of Chen and Lee teaches the invention as explained above in claim 14, and further teaches monitoring the series of OES measurements for an indication of an endpoint of the pulsed plasma process (Chen: paragraph [0005]); and
instructing the plasma processing apparatus to terminate the pulsed plasma process in response to detecting the endpoint (Chen: inherent to endpoint detection).
Chen discloses the indication of an endpoint is necessary to ensure the underlying layer is not etched through (paragraph [0005]), therefore also necessitating the plasma processing to be terminated. Thus, it would be obvious for a person of ordinary skill in the art to combine the device of Mihaylov as modified by Chen and Lee with the endpoint indication taught in Chen in order to ensure there is no unwanted etching.
Regarding claim 19, Mihaylov in view of Chen and Lee teaches the invention as explained above in claim 14, and further teaches selecting a second wavelength for an additional adjustable wavelength filter of the OES detection device (Mihaylov: paragraph [0043] discloses multiple wavelength filters); and
wherein collecting the series of OES measurements of the plasma comprises simultaneously collecting a first series of OES measurements at the first wavelength and collecting a second series of OES measurements at the second wavelength (Mihaylov: paragraph [0043] discloses multiple wavelength filters in the same optical path, but associated with different channels. The examiner is interpreting this to mean they measurements are taken at the same time), each of the first and second series of OES measurements comprising a temporal resolution less than a millisecond so that multiple OES measurements of each of the first and second series are collected for each RF SP pulse of the sequence (Mihaylov: paragraph [0034] discloses the device is capable of detecting pulses started in the nanosecond range).
Claims 15, 16, 20, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Chen (US20200373210A1) and Lee (US20160126068A1) as applied above to claim 14, further in view of Mahoney (US20050034811A1).
Regarding claim 15, Mihaylov as modified by Chen and Lee teaches the invention as explained above in claim 14, and further teaches receiving the synchronization signal from an SP power control path of the power control path, the SP control path being configured to control application of the sequence of RF SP pulses to the plasma processing apparatus (Lee: see Fig. 1A, which depicts a pulse controller controlling the RF pulse generators and sending the synchronization signal).
As explained above in claim 14, it would be obvious for a person of ordinary skill in the art prior to the effective filing date to combine the method of Mihaylov as modified by Chen and Lee with the synchronization signal taught in Lee in order to enable precise semiconductor etching.
Mihaylov as modified by Chen and Lee fails to teach synchronizing the series of OES measurements with the sequence of RF SP pulses to ensure locked-in synchrony with pulsing of the plasma by triggering a setup delay in response to receiving the synchronization signal; and
starting acquisition of the series of OES measurements after the setup delay.
However, Mahoney teaches a method of synchronizing data acquisition with plasma pulses (paragraph [0055]) through a delay and holding signal before triggering the sensor (paragraph [0056]).
Mahoney discloses that the method of synchronization used allows for plasma variations caused by the plasma pulses to be accounted for (paragraph [0055]) and avoids noise in the sensor readings, making the readings more accurate (paragraph [0056]). Thus, it would be obvious for a person of ordinary skill in the art to combine the method of Mihaylov as modified by Chen and Lee with the measurement synchronization taught in Mahoney in order to take more accurate measurements.
Regarding claim 16, Mihaylov as modified by Chen, and Lee teaches the invention as explained above in claim 14, but fails to teach repeating the step of collecting the series of OES measurements from the plasma in response to receiving additional synchronization signals, each corresponding to additional sequences of RF SP pulses.
However, Mahoney teaches a method of repeating measurements and therefore signals (paragraph [0058] discloses multiple signals; Fig. 10 also depicts multiple RF pulse sequences).
The method of repeating measurements is well-known and widely used in the art to ensure the measurements are accurate by verifying repeatable, which minimizes outliers and errors. Thus, a person of ordinary skill in the art would find it obvious to combine the method of Mihaylov as modified by Chen and Lee with the repeated measurement step taught in Mahoney in order to minimize outliers and errors in the measurement.
Regarding claim 20, Mihaylov as modified by Chen, and Lee teaches the invention as explained above in claim 14, and further teaches collecting the series of OES measurements during a selected portion of a source power "on" power cycle applied during each power cycle of the sequence of RF SP pulses (Lee: paragraph [0014] and [0063] discloses only taking some of the measurements during a pulse-on period).
As discussed in claim 14, it would be obvious for a person of ordinary skill in the art prior to the effective filing date to combine the method of Mihaylov as modified by Chen and Lee with the measurements only taken during a certain period signal taught in Lee in order to enable precise semiconductor etching.
Mihaylov as modified by Chen and Lee fails to teach switching off collection of the series of OES measurements during remaining portions of each power cycle.
However, Mahoney discloses turning the sensors on and off to synchronize with the rf plasma pulse cycle (paragraph [0058]).
Mahoney discloses that the method of turning the sensors on and off avoids noise in the sensor readings, making the readings more accurate (paragraph [0056]). Thus, it would be obvious for a person of ordinary skill in the art to combine the method of Mihaylov as modified by Chen and Lee with the method taught in Mahoney in order to take more accurate measurements.
Regarding claim 21, Mihaylov as modified by Chen, and Lee teaches the invention as explained above in claim 14, but fails to teach wherein collecting the series of OES measurements of the plasma only during the selected portion further comprises:
collecting the series of OES measurements during a selected portion of a wafer bias "on" power cycle applied during each power cycle of a sequence of wafer bias pulses applied to a substrate holder supporting a wafer, each of the wafer bias pulses being in synchrony or out of synchrony with the RF SP pulses; and
switching off collection of the series of OES measurements during remaining portions of each power cycle of the sequence of wafer bias pulses including a wafer bias "off' power cycle of each power cycle of the sequence of wafer bias pulses.
However, Mahoney teaches the collection of measurements may be synchronized with a power cycle due to anything between the power supply and plasma source (paragraph [0058]), which may also include a bias voltage applied to the wafer (paragraphs [0018], [0035]). Mahoney further discloses the collection may be synchronized with the power cycle and only take measurements during an on or off period (paragraph [0058]).
Mahoney discloses that voltage biases applied to the wafer holder are often required in various processing methods (paragraph [0035]), therefore making it necessary to account for the voltage bias as it influences measurements (see Fig. 4b). Thus, a person of ordinary skill in the art would find it obvious to combine the method of Mihaylov as modified by Chen and Lee with the ability to synchronize with the wafer bias taught in Mahoney in order to account for the influence a wafer bias has on measurements.
Claim 22 is rejected under 35 U.S.C. 103 as being unpatentable over Mihaylov (US20170140905) in view of Chen (US20200373210A1), Lee (US20160126068A1) and Mahoney (US20050034811A1) as applied above to claim 21, further in view of Pape (US20090002836A1).
Regarding claim 22, Mihaylov as modified by Chen, Lee and Mahoney teaches the invention as explained above in claim 21, and further teaches reporting, in real-time (Mihaylov: paragraph [0033]), differences between OES measurements from the center of the wafer and OES measurement from edges of the wafer (Mihaylov: paragraph [0079]).
Mihaylov as modified by Chen, Lee and Mahoney fails to teach collecting the series of OES measurements utilizing light collection through a gimbal.
However, in the same field of endeavor of OES devices used in plasma processing devices, Pape teaches a collimator arrangement used in OES measurements that may be on a gimbal (paragraph [0042] discloses the arrangement may allow for "gimballing motion". The examiner is interpreting that to mean a gimbal is used).
Pape disclosed a gimbal allows the best alignment relative to other components (paragraph [0066]). Thus, it would be obvious to a person having ordinary skill in the art prior to the effective filing date to combine the method of taking measurements at different points of the wafer taught in Mihaylov as modified by Chen and Lee with the gimbal taught in Pape to ensure the best alignment.
Conclusion
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/ALEXANDRIA MENDOZA/ Examiner, Art Unit 2877
/MICHELLE M IACOLETTI/ Supervisory Patent Examiner, Art Unit 2877
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