23/07 '09 16:86 FAX 02073588895
`
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`FRANK B.DEHN
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`—> EPO MUNICH
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`.001
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`I Patent and Trade Mark Attorneys
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`Robert Jackson
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`European Patent Application No. 037765849 (1556882)
`Regional Phase of PCT Application PCT/U32003/034191
`Zond, Inc.
`
`31.2.87738
`
`To
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`From I
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`Our Ref
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`Your Ref
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`Date
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`23 July 2009
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`Number of Pages (including this one) : ll
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`Comments
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`:
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`Putnam
`Chrlaiophar P Pm MA
`Kerry J Tomlimon MA
`Michael J Butlar MA
`Julian Cuckbaln MA omi
`Chrisxopher R Davies BS:
`Alexander J Piésnld BS:
`Dunk P Matthews ES: PhD
`Hanna Dzloglcwska 65: PhD
`Raberm Calamim MA
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`David Lackey 35c
`Alison J Hague MA
`Philip D 'I‘owler MA
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`Received at the EPO on Jul 23, 2009 17:44:44. Page 1 of 21
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`GIL
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`LETTE 1007
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`GILLETTE 1007
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`

`

`
`23/07 '09 16:36 FAX 02073538895
`FRANK B.DEHNI
`_____ __________..—-——
`
`—> EPO MUNICH
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`.002
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`St Bride's House, 10 Salisbury Square, London EC4Y 8J0
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`dare 23 July 2009
`your ref
`curref 31.2.87738
`
`BY FACSIMILE
`
`Dear Sirs
`
`European Patent Application No. 037765343 (1556382)
`Regional Phase of PCT Application PCT/USZOO3/034191
`20nd, Inc.
`I hereby request fuIther processing of this application in accordance with Article 121 EPC.
`
`I enclose a Fee Voucher authorising the withdrawal of the further processing fee
`from our Deposit Accomt No. 28050069 in respect of the fee for further processing.
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`A response to the Official Communication of 18 September 2008 is filed herewith,
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`A Form 1037 f0110ws with the confirmation of this facsimile for acknowledgement purposes.
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`YOurs faithfully
`Frank B. Dehn & Co.
`
`Robert Jackson
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`Enos
`shr
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`Partners
`Chrlstophar P Pen MA "
`Karry J Tomllnson MA r
`Mlchaal J ButlerMA ..
`Julian Cuckbaln MA om ~-
`Chrlsmphcr R Davies55: "
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`'UK Chartered Patent Attorney, European Patent Attorney 'UK Rnginered Trade Mark Attorney, European Trade Mark Attorney
`Received at the EPO on Jul 23, 2009 17:44:44. ng 19%;” Munich Brighton Oxford
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`23/07 '09 16:36 FAX 02073538895
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`FRANK Bf'DEHN
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`., EPO MUNICH
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`LLondon, 23 July 2009
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` EPO101004.05
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`Explains
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`. 1-4 mm overleaf.
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`Fives, dale
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 3 of 21
`
`
`
`

`

`
`23/07 '09 16:37 FAX 02073588895
`FRANK B.DEHN
`
`—> EPO MUNICH
`
`.004
`
`FRANI< B DEHN 8 C0
`*________________,____.._—————-'——-"‘—-—
`Patent and Trade Mark Attorneys
`
`5t Bride's House, 10 Salisbury Square. London EC4Y BJD
`Telephone; +44 (0)20 7632 7200 Fax +44 (0)20 7353 3895
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`
`date 23 July 2009
`your ref
`omd 31.2.87738
`BY FACSIMILE
`
`Dear Sirs
`
`European Patent Application No. 03776584.9 (1556882)
`Regional Phase of PCT Application PCT/U520031034191
`Zond, Inc.
`In response to the Examination Report dated 18 September 2008, we enclose herewith amended
`pages 1, la, 1b and 30—32 to replace pages 1 and 30-31 currently on file. To aid the Examiner,
`we also enclose a draft copy of those pages in which the changes made to the text can be clearly
`3631).
`
`Prior Art Effect of D4
`We shall first address the question of the relevance of D4 to the claims of this application.
`This application was filed on 28 October 2003, before EPC 2000 came into force and therefore,
`according to the transitional provisions, Arts 53(3) and (4) and Rule 23a EPC 1973 continue to
`apply. A priority date of 29 October 2002 is claimed from United States Patent Application No.
`10/065,55 1, a copy of which was filed at the International Bureau in the International phase.
`The content of the priority document and this application is identical. Therefore all claims of
`this application are entitled to priority from this docturnent and have an effective date of 29
`October 2002.
`
`D4 was filed on 14 June 2002, before the effective date of the claims of this application, but was
`published on 27 December 2002, after the effective date of the claims. Thereafter D4 entered
`the European regional phase. This document is therefore prior art only in accordance with Art
`54(3),(4) EPC 1973. Applying Rule 23a EPC 1973, designation fees were paid in relation to
`D4 in respect of all states designated in the present application except Bulgaria, Czech
`Republic, Estonia, Hungary and Slovakia. D4 is therefore not prior art in these states. In
`respect of all remaining states designated in this application, D4 can be taken into consideration
`for novelty only.
`
`Amendments
`Turning now to the amendments, the Examiner Will note that claim 1, directed to a
`magnetically enhanced plasma source, has been amended to include features of previous
`Partners
`David Lackeyas: -'
`Annabel R 3433:}thMA on,” -
`Associates
`Dani=l Rowe as: the '
`Christopher P FcttMA "
`Alison J HagueMA "
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`Jamn Stevens BA '
`Barbara N R195! MA PhD ‘
`Kerry J Tomlinson MA -
`Philip D TowlarMA"
`Neil Campbell 513'
`Katharina F Mahey MA '
`Richard Goddard as; Ms: ‘
`Michael J ButlnrMA"
`Andrea M Hughes BEnn LLM "
`Philip M Webber MA PhD v
`Christopher R Goddard MAFhD -
`Adam Taylor MEng -
`Julian Cackhaln MA om ~"
`John F Tothlll MA -
`Matthew Hg“ in ME: ~
`Clare L Stancman BA'
`Laura Ramsay MA Mk5 v
`Christopher R Davies55:"
`Robert P Jackson as: LLM ‘
`Elaine F Bayer 59: .
`Ann: Leathley MBind—m mo '
`Kerry Bridge 55: PhD -
`Alexander J Plésold as: "
`Bizaberh Jones MS: PhD '
`Joseph M Letting LLB (Hons) '
`Andrew Chive MScl -
`Derek P Matthews as: PhD '
`Louise A Gnldlng MA -
`Deborah J Owen MA PhD '
`Joell: Rutherford as: mo -
`Hanna Dzieglewska as: who .-
`RchCCE Gardner as: '
`5‘ePh9I'I Gardiner Why! '
`Roberto Calnmlta MA "
`Phlllp M Jeffrey 35: PhD '
`Sara Kidd 35: PM) '
`‘UK Charmrcd Parent Attorney, European Patent Attorney 'UK Rugimmd Tradn Mark Attorney. European Trade Mark Attorney
`Received at the EPO on Jul 23, 2009 17:44:44. Pagfg 4 0cc: inlgtlon Munich Brlghton Oxford
`
`

`

`
`23/07 '09 16:37 FAX 02078588895
`FRANK B.DEHN
`
`» EPO MUNICH
`
`I005
`
`FRANK B. DEHN 8 Co.
`
`231111,: 2009
`31.2.87738
`
`- 2 r
`
`dependent claims 3 and 5 and also to recite that the weakly—ionized and stronglyvionized
`plasmas are generated from afeed gas. Previous claims 3 and 5 have been deleted and the
`remaining claims have been renumbered accordingly.
`Basis for the included features of previous dependent claim 3, which recites to a voltage biased
`substrate positioned proximate the cathode, can be found in the International application as
`filed in original independent apparatus claim 1 of the PCT publication. Basis for the included
`features of previous dependent claim 5, which recites the power supply generating an electrical
`field pulse, can be feund in the International application as filed in original dependent
`apparatus claim 3 of the PCT publication, as well as throughout the specification (see, for
`example, Figure 4 and paragraph [015 1]). Basis for claiming that the weakly- and strongly—
`ionized plasma that is generated in the apparatus in accordance with the invention is a gas
`plasma produced from the feed gas can be found in the application as filed in paragraphs
`[0033], [0043]—[0048], [0060]-[0068], [00741—[0081] and [0147]~[0156]. These paragraphs
`also provide clear basis for claiming that the power source is arranged to apply an electrical
`pulse across the weakly~ionized feed gas plasma to produce a pulsed electrical field that
`generates a strongly-ionized gas plasma.
`
`An independent method claim 10, which complements independent apparatus claim 1 in
`scope, has been introduced into the claims based on original method claim 15.
`
`Summagy of the Invention
`Amended claim 1 now rec1tes a plasma source that generates, from a feed gas, a strongly-
`ionized gas plasma which performs a gas plasma etching process (particularly for the plasma
`etching processes described in paragraphs [001] and [002]) on a substrate by a two—step
`ionization process.
`
`In this process, an ionization source (that may be provided, for example, by a relatively low-
`power electrical field pulse across the anode and the cathode, or by a UV source, X—ray source,
`etc.) is arranged to ionize a feed gas to produce, as a first step in the two-step process, a
`relatively weakly—ionized gas plasma (Le. containing ions of the feed gas and having a relatively
`low plasma density of ions of, for example, anywhere between 1004012 ions/cm3 for an Argon
`feed gas (see paragraph [0046]». After ionization by the ionization source, the feed gas ions of
`the weakly ionised plasma are trapped in the region pr0ximate the cathode by the magnetic field
`produced by the magnet.
`
`The second stage of the claimed two-step ionisation process then occurs, with the power source
`applying an electrical pulse between the anode and the cathode which produces an electrical
`field pulse across the weakly—ionized gas plasma and generating, by producing excited
`atoms/molecules in the weakly—ionized feed gas plasma and secondary electrons from the
`cathode, a strongly-ionized gas plasma of the feed gas (i.e containing ions of the feed gas and
`having a relatively high plasma density of ions compared to the relatively weakly-ionised
`plasma).
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 5 of 21
`
`

`

`23/07 '09 16338 FAX 02073538895
`
`FRANK B.DEHN
`
`—> EPO MUNICH
`
`.006
`
`FRANK B, Darn: Er Co.
`
`23111137 2009
`31.237733
`
`- 3 -
`
`A substrate to be processed (for example, a semiconductor wafer) is positioned proximate to
`the cathode and a bias voltage is applied to the substrate by a voltage supply such that the ions
`of the strongly—ionized feed gas impact the surface of the substrate to process the substrate (see
`paragraph [0034]. Depending on the substrate, nature and reactivity of the gas, and energy of
`the gas ions on reaching the substrate, the substrate is processed by the plasma source in
`different ways. In the embodiment set out in the description, an Argon feed gas is provided to
`produce from the plasma scurce an Ar+ plasma which is then used to etch the substrate.
`In practical operation of the claimed plasma etching source, the claimed twoastep ionization
`process would be cyclically repeated (at a suitable frequency e.g. between 0.1Hz—1kHz) to
`maintain the gas plasma in at least its weakly—ionized state and to periodically regenerate the
`plasma to its strongly-ionized state. In this way, gas plasma processing of the subsrrate can be
`cominued for a desired period of time. In this way the claimed generation of a weakly—ionized
`gas plasma before a high—power pulse is applied to further ionized the gas plasma to a strongly—
`ionized state allows a dense gas plasma to be produced for etching of a Substrate while reducing
`the probability of an electrical breakdown condition and thus preventing arc generation in the
`plasma source that would otherwise harm the processing of the substrate.
`
`Novelty
`We will now set Out how the plasma source of amended claim 1 is novel over each citation
`beginning with D1.
`
`D1 discloses a magnetically enhanced sputtering apparatus for physical vapour deposition of a
`thin film of a sputter target material 9 (provided as a cathode) on a substrate 13. A plasma is
`created by high voltage pulsing of a feed gas to bombard the cathode 9 and cause sputter target
`material to be ejected and subsequently coat the substrate 13. The plasma itself does not
`bombard the substrate 13. Thus in D1, the sputtering apparatus is not arranged Such that ions
`of the plasma bombard the substrate to process the substrate, as required in amended claim 1.
`
`Further, the Substrate 13 in the apparatus of D1 is electrically isolated and has a neutral
`electrical potential (see page 1 lines 1—7, page 9 lines 5—6 and page 9 line 18). Thus D1 does not
`disclose providing a voltage supply arranged to apply a bias voltage to a substrate positioned
`proximate to the cathode, as required in amended claim 1.
`
`Further, we submit that, for the following reasons, and contrary to the Examiner’s assertion in
`item 2.1 of his report, D1 does not disclose the claimed ionization somce. In the sputtering
`apparatus of D1 a pulsed power scurce 18 is arranged (such as shown in Figure 6) to apply
`electrical voltage pulses initially across a feed gas input at inlet 21 between the sputter target
`cathode 9 and an anode 5 (i.e. the walls of the evacuation chamber 3). The power source is
`arranged to apply high power electrical voltage pulses having a waveform, for example as shown
`in Figure 8, With a very fast rise time, typically of at most a few microseconds, to a peak value of
`a few kilovolts (see page 12 lines 22—24). The purpose of this very fast rise time is to suddenly
`transform the feed gas into a completely ionized plasma (i.e. the state ‘88‘ shown in Figure l) by
`quickly applying a discharge voltage across the feed gas in the EXB region having a magnitude
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 6 of 21
`
`

`

`23/07 ’09 16:39 FAX 02073538895
`
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`FRANK B.DEHN
`
`—> EPO MUNICH
`
`I007
`
`FRANK B. DEHN 8‘ C0.
`
`2311113; 2009
`31.2.87738
`
`- 4 -
`
`greater than the burn—out voltage of the plasma source (see page 8 lines 13-28 and page 12 line
`24—26). A plot of discharge voltage against Current density is shown in D1. It should be noted
`that this is not a time plot of the discharge voltage produced by the sputtering apparatus of Dl
`on the application of the voltage pulse (this is shown in Figure 8). Rather, during this very brief
`rise time of the pulse, the feed gas immediately runs through the states ‘8 1‘ to ‘S7' shown in
`Figure 1(including a glow discharge state '84‘), and an electric are state '87" results (see page 12
`lines 26—29 and claim 1). In this intermediate 'S7‘ state, are discharges momentarily occur (see
`Figure 2 and page 10 lines 6—1 1) before the voltage exceeds the burn—Out voltage and a
`completely ionized state (88‘) is achieved. In D1, the sputtering apparatus is therefore arranged
`to provide a fully ionized plasma through the generation ofintermediate are discharges. In contrast,
`in the plasma source of the present invention, the taro-step ionization process Substantially
`eliminates the occurrence of arc discharges.
`
`In D1, after the brief high voltage pulse of the power source disappears (see Figure 8), the
`completely ionised state (’88') of the plasma cannot be maintained and the plasma disappears,
`reverting back to its non-ionized state (see page 12 line 29-33). Thus the power source 18 of
`D1 is arranged to always apply high voltage pulses across the feed gas itself, in a non-ionized
`state, and not across a weakly—ionised plasma, as required in amended claim 1. There is
`therefore no disclosure in D1 of the claimed ionization source which is arranged to partially
`ionize the feed gas befm-e the power source 18 applies a high voltage pulse. Instead, it is only as a
`result of the application of the high voltage pulse by the power scurce that the feed gas becomes
`very rapidly partially, then fully ionized, and not as a result of some separate pie-ionization
`means.
`
`Finally, we submit that the apparatus of D1, in normal use, does not previde a gas plasma in the
`region adjacent the cathode, as required by amended claim 1, but rather a gas-metal plasma is
`produced. Material ejected from the sputtering target 9 of D1 by ion bombardment interacts
`with the fully ionized plasma trapped in the magnetic field of the magnets 17 to itself become
`ionized by excitation. The metal ions of the sputtering target then themselves become trapped
`in the magnetic field such that, immediately after the first high voltage pulse is initiated in the
`sputtering process, a gas-metal plasma is produced.
`
`In contrast, in the claimed invention where the plasma source operates as a plasma etcher,
`sputtering from the cathode does not occur (see paragraph [0095]) and the plasma produced by
`the claimed plasma source is provided by feed gas ions, with no metal ions being produced in
`the region proximate the cathode.
`
`Turning now to the other citations, D4 is similar to D1 in that it discloses a magnetically
`enhanced sputtering apparatus (see Figures 12a and 12b) for sputtering material from a cathode
`23 by bombardment from ions of a plasma generated by a power source 26 applying electrical
`field pulses between the cathode 23 and an anode 24. There is no disclosure in D4, either
`explicit or implicit, of a substrate to be processed or of a voltage Supply arranged to apply a bias
`voltage to the substrate to cause ions of the plasma to bombard the substrate, as required in
`amended claim 1. Further, operation of the sputtering apparatus of D4 relies on self—sputtering
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 7 of 21
`
`

`

`23/07 '09 16:40 FAX 02073538895
`FRANK B.DEHN
`—) EPO MUNICH
`
`
`I008
`
`FRANK B. Dam: Er Co.
`
`23 July 2009
`31.2.87738
`
`- 5 -
`
`of the cathode by ions of the cathode material produced by interaction of the sputtered material
`and the plasma, the cathode metal ions being trapped in the magneuc field to produce a gas-
`metal or preferably a metal plasma (see page 7 lines 12-20, page 13 line 33 to page 14 line 7).
`Rather, in normal operation of the apparatus ofD4, a feed gas is provided only as a seed for the
`gas—metal or metal plasma, which is generated by the sputtering apparatus. Thus D4 does not
`disclose an apparatus for generating a strongly ionised gas plasma for impacting the surface of a
`substrate having a biased voltage, as required by amended claim 1.
`D2 discloses a plasma sputter etching/deposition device including a hollow cathode are source
`and a magnetron. D3 discloses a plasma processing apparatus for sputtering deposition on a
`substrate arranged on an anode of a sputtering target material provided on a cathode. There is
`no teaching in either D2 or D3 of providing a substrate to be processed by bombardment by a
`gas plasma etchant proximate to a cathode, or of providing a voltage source arranged to apply a
`bias voltage to the substrate SuCh that the gas plasma ions impact the substrate Surface, as
`required by amended claim 1. Further, the power Supply arranged between the anode and the
`cathode in both D2 and D3 provides a constant DC or AC voltage signal and is not arranged to
`provide an electrical field pulse, as required by amended claim 1.
`
`We therefore Submit that amended claim 1 is novel.
`
`Inventive step
`While we note there is currently no outstanding inventive step objection, to assist the Examiner,
`we provide the following comments.
`
`D1 may be considered the closest prior art as this document discloses a plasma processing
`apparatus having similar arrangement to the claimed invention and it uses high power pulses to
`achieve high intensity plasmas. D2 and D3 are clearly very different arrangements of apparatus
`and do not disclose high power pulses. D4 is not. prior art for the purposes of inventive step
`assessment.
`
`D1 is, for the reasons given above, very different to the invention now claimed in that it relates
`to a sputtering apparatus for coating a substrate with a sputtering material, wherein a high
`intensity gas—metal plasma is created by applying high power pulses across a feed gas/metal
`vapour to bombard a sputtering cathode and sputter material away to coat a subscrate.
`
`The present invention, in contrast, relates to a plasma source in which a strongly—ionized gas
`plasma is produced by a twvstep ionization process in which high voltage pulses are applied
`across a pre—ionized weakly-ionized plasma. The gas plasma is then attracted to a voltage biased
`substrate Which it bombards to etch the Substrate.
`
`There is no teaching or suggestion in D1, D2 or D3 of a two-step ionization process to produce
`a strongly ionized gas plasma Such as that provided in the plasma scurce of amended claim 1.
`Further, there is no teaching or Suggestion in D1, D2 or D3 of providing a voltage biased
`substrate proximate to the cathode such that the substrate is processed by bombardment by the
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 8 of 21
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`

`

`28/07 '09 18:40 FAX 02073538895
`
`FRANK B.DEHN
`
`
`—> EPO MUNICH
`
`@009
`
`FRANK B. DEH’N Er Co.
`
`231111;: 2009
`31.2.87738
`
`- 6 -
`
`gas plasma. There is therefore nothing in the cited art that would motivate the skilled man to
`provide the plasma etching source claimed in amended claim 1.
`l
`The plasma sOuIce of the present invention provides for efficient gas plasma etching of a
`substrate with a reduced likelihood of harmful electrical arcs occurring in the processing
`chamber. In contrast, as stated above, in D1) the sputtering apparatus is arranged to provide a
`fully ionized plasma through the generation of intermediate arc discharges.
`
`We therefore submit that amended claim 1 provides inventive step.
`As independent method claim 12 corresponds in scope to independent apparatus claim 1, the
`submissions presented above in support of the novelty and inventiveness of claim 1 therefore
`also apply to method claim 12 mumzis murandis. We therefore submit that claim 12 is also novel
`and provides inventive step.
`
`Clari
`and formalities
`‘
`The Examiner will note that the amendments to the claims address each of his clarity objections
`in item 3.1 of the Examination Report.
`
`An acknowledgement of D1 and a statement of the now—claimed invention have been inserted
`into the description. Reference numbers have also been inserted into the claims.
`
`However, the claims are not arranged in tWOApart form as this is only an optional of the EPC
`where it is appropriate. In this case, we Submit that the clarity of the current claims WOuld be
`deleteriOusly affected if they were arranged in two-part fonn, and it is therefore not appropriate
`in this case.
`.
`
`We trust this application is now in order for grant. However, if there are any objecrions we
`request a further Examination Report or the opportunity to discuss the objections with the
`Examiner by telephone.
`If, despite this, the Examining Division is at any stage intending to
`refuse this application for any reason, we hereby requesr Oral Proceedings.
`
`Please acknowledge receipt of this letter by date-stamping a returning the Form 1037, which will
`follow with the confirmation copy of this facsimile.
`
`Yours faithfully
`Frank Dehn & Co.
`
`Robert Jackson
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 9 onl
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`

`
`23/07 '09 18:41 FAX 02073538895
`FRANK B,DEHN
`
`a EPO MUNICH
`
`I010
`
`.1-
`
`High—Power Pulsed Magnetically Enhanced Plasma Processing
`
`Background of Invention
`
`[0001} Plasma processes are widely used in many industries, such as the
`semiconductor manufacttm'ng industry. For example, plasma etching is widely used in
`the semiconductor manufacturing industry. There are four basic types of plasma
`etching processes that are used to remove material fiom surfaces: sputter etching, pure
`chemical etching, i011 energy driven etching, and ion inhibitor etching.
`
`[0062] Spotter etching is the ejectiori of atoms from the surface of a substrate due to
`energetic ion bombardment Pure chemical etching uses a plasma discharge to supply
`gas-phase etchant atoms or molecules that chemically react with the surface of a
`substrate to form gas-phase products. ion—enhanced energy driven etching uses a
`plasma discharge to supply both etchaut and energetic ions to a surface ofa substrate.
`ion inhibitor etching uses a discharge to provide etchaut, energetic ions, and inhibitor
`precursor molecules that deposit on the substrate to form a protective layer film. It is
`desirably to increase the uniformity and etch rate of known sputter etching systems.
`
`International patent application publication number WO—A—9 8/40532 discloses a
`
`sputtering apparatus for coating a substrate with a sputtering material, wherein a high
`intensity gas-metal plasma is created by applying high voltage pulses across a feed
`
`gas/metal vapour to bombard a sputtering cathode and sputter material away to coat a
`
`substrate.
`
`Summary of the Invcnfi0n
`
`Viewed frdm one aspect, the invention provides a magnetically enhanced plasma
`
`source comprising: an anode; a cathode that is positioned adjacent to the anode; an
`
`ionization source that is arranged to, in use, ionize a feed gas to generate a weakly-
`
`ionizcd gas plasma; a magnet that is positioned to generate a magnetic field
`
`proximate to the weakly-ionized plasma, the magnetic field substantially trapping
`electrons in the weakly-ionized plasma proximate to the cathode; a power supply
`
`arranged to produce an electric field pulse across the anode and the cathode and
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 10 of 21
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`

`

`23/07 '09 16:41 FAX 02078538895
`
`FRANK B.DEHN
`
`—> EPO MUNICH
`
`.011
`
`-1a-
`
`across the weakly-ionized gas plasma, the electric field pulse generating, in use, at
`least one of excited atoms and excited molecules in the weakly—ionized gas plasma
`and generating secondary electrons horn the cathode, the secondary electrons
`ionizing the excited atoms, thereby creating a strongly—ionized gas plasma
`comprising a plurality of ions of the feed gas; and a voltage supply arranged to apply
`a bias voltage to a substrate that is positioned proximate to the cathode, the bias
`voltage being so as to cause ions in the plurality of ions ofthe feed gas to impact a
`surface of the substrate in a manner that processes the surface ofthe substrate (211).
`
`Viewed from another aspect, the invention provides a method of magnetically
`enhanced gas plasma processing of a substrate, the method comprising: ionizing a
`feed gas to generate a weakly-ionized gas plasma proximate to a cathode; generating a
`magnetic field proximate to the weakly~ionized gas plasma, the magnetic field
`substantially trapping electrons in the weakly-ionized gas plasma proximate to the
`cathode; applying an electric field pulse across the weakly—ionized plasma that
`generates at least one of excited atoms and excited molecules in the weakly-ionized
`gas plasma and that generates secondary electrons from the cathode, the secondary
`electrons ionizing the excited atoms, thereby creating a strongly-ionized gas plasma
`
`comprising a plurality of ions of the feed gas; and applying a bias voltage to a
`substrate that is positioned proximate to the cathode, the bias voltage causing ions of
`
`the feed gas in the plurality of ions to impact a surface of the substrate in a manner
`
`that processes the surface of the substrate.
`
`Brief Description of Drawings
`
`[0003] This invention is described with particularity in the detailed description. The
`above and further advantages of this invention may be better understood by referring
`
`to the following description in conjunction with the accompanying drawings, in which
`
`like numerals indicate like structural elements and features in various figures. The
`
`drawings are not necessarily to scale, emphasis instead being placed upon illustrating
`
`the principles of the invention.
`
`[0004] FIG. 1 illustrates a cross-sectional View of a known magnetically enhanced
`etching apparatus having 5. having a radio-frequency (RF) power supply.
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 11 of 21
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`

`

`
`23/07 '09 16242 FAX 02073538895
`FRANK B.DEHN
`
`—> EPO MUNICH
`
`I012
`
`-1b-
`
`[0005] FIG. 2 illustrates a cross—sectional View of an embodiment of a magnetically
`enhanced plasma processing apparatus according to the present invention.
`
`Received at the EPO on Jul 23, 2009 17:44:44. Page 12 of 21
`
`

`

` 2073538895 FRANK B.DEHN
`28/07 ‘09 16:42 FAX 0
`
`
`
`_
`
`4 EP0 MUNICH
`
`@013
`
`-30-
`
`Claims:
`
`1.
`
`A magnetically enhanced plasma source (200; 450; 450'; 450") comprising:
`
`a)
`
`b)
`
`0)
`
`d)
`
`an anode (23 8);
`a cathode (216) that is positioned adjacent to the anode (233);
`an ionization source That is arranged to, in use, ionize a feed gas to
`
`generate a weakly—ionized gas plasma;
`a magnet (256) that is positioned to generate a magnetic field
`proximate to the weakly-ionized plasma, the magnetic field
`substantially trapping electrons in the weakly—ionized plasma
`
`proximate to the cathode (216);
`a power supply (234) arranged to produce an electric field pulse
`across the anode (23 8) and the cathode (216) and across the
`
`weakly—ionized gas plasma, the electric field pulse generating, in
`use, at least one of excited atoms and excited molecules in the
`weakly~ionized gas plasma and generating secondary electrons from
`the cathode (216), the secondary electrons ionizing the excited
`
`atoms, thereby creating a strongly—ionized gas plasma comprising a
`
`plurality of ions of the feed gas; and
`
`a voltage supply (214) arranged to apply a bias voltage to a
`
`substrate (211) that is positioned proximate to the cathode (216), the
`
`bias voltage being so as to cause ions in the plurality of ions of the
`
`feed gas to impact a surface of the substrate (211) in a manner that
`
`processes the surface of the substrate (211).
`
`2.
`
`3.
`
`4.
`
`The plasma source (200; 450; 450'; 450") of claim 1, wherein the power
`
`supply (234) comprises the ionization source.
`
`The plasma source (200; 450; 450'; 450”) of claim 1, wherein the voltage
`supply is operable such that, in use, the bias voltage is selected to control
`ion energy of the i