IND
`
`APPLICATION TRANSMITTAL
`
`Atty. Docket No.
`
`_16655-0003
`
`oc.lUwH
`ac =
`Mas SB
`——
`ne =>
`Poo ==0
`to =o
`oS
`oo =
`"Express Mail" Label No.
`05855
`o_
`
`Date ofDeposit
`[ug 5D, l 49 /
`
`+
`
`& ===0WNSEND and TOWNSENDand CREW LLP
`.
`ibarcadero Center, 8th Floor
`rrErancisco, CA 94111-3834
`> ==>326-2400
`
`i—
`
`w)=F
`
`—
`©=PATENT APPLICATION
`Thereby certify that this is being deposited with the
`ASSISTANT COMMISSIONER FOR PATENTS
`United States Postal Service "Express Mail Post Office
`Washington, D. C. 20231
`to Addressee" service under 37 CFR 1.10 on the date indicated
`above and is addressed to:
`
`Sir:
`Transmitted herewith for filing is the [ ] patent application,
`[ ] design patent application, [X] continuation-in-part patent
`application of
`
`Inventor(s): Daniel L. Flamm
`
`Assistant Commissioner for Patents
`Washington, D.C. 20231
`
`
`
`For: PROCESS DEPENDING ON PLASMA DISCHARGES SUSTAINED BY INDUCTIVE CO
`
`ING
`
`[X] This application claims priority from each of the following Application Nos./filing dates:
`
`
`
`08/567,224 ;_08/736,315/ December 4, 1995 /_ October 23, 1996 ;
`
`
`
`T]
`
`--This application claims the benefit of U.S. Provisional
`Please amend this application by adding the following before the first sentence:
`Application No. 60/
`, filed
`, the disclosure of which is incorporated by reference.--
`
`
`
`
`‘Enclosed are:
`
`[X] Patent Application (incl. 26 pages spec., _/ pages claims, 1 page abstract).
`[xX]
`i3
`sheet(s) of [ ] formal
`[X] informal drawing(s).
`] An assignment of the invention to
`] A[ ]signed [] unsigned Declaration & Power of Attorney.
`] A verified statement to establish small entity status under 37 CFR 1.9 and 37 CFR 1.27 [] is enclosed [ ] was filed
`in the earliest of the above-identified patent application(s).
`] A certified copy of a
`]
`Information Disclosure Statement under 37 CFR 1.97.
`]_Apetition to extend time to respond in the parent application of this continuation-in-part application.
`[X] Postcard.
`
`
`
`
`application.
`
`Pursuant to 37 CFR 1.53, Applicant requests deferral ofthe filing fee until submission of the Missing Parts of Application.
`
`Telephone:
`(415) 326-2400
`16655\3-1-lapp.tm
`
`Respectfully submitted,
`
`TQWNSENDand TOWNSENDand CREW LLP
`
`Lan
`
`
`
`Richard T. Ogawa
`Reg. No.: 37,692
`Attorneys for Applicant
`
`

`

`HN0/97
`A
`Date ofDepositMiy50,1497
`
`TOWNSENDand TOWNSENDand CREW LLP
`
`Two Embarcadero Center, 8th Floor
`’ San Francisco, CA 94111-3834
`(415) 326-2400
`
`APPLICATION TRANSMITTAL
`
`Atty. Docket No.
`
`-
`
`"Express Mail" Label No.
`
`4708/866040
`
`O5/3
`
`PATENT APPLICATION
`ASSISTANT COMMISSIONER FOR PATENTS
`Washington, D. C. 20231
`
`Sir:
`Transmitted herewith for filing is the [ ] patent application,
`[ ] design patent application, [X] continuation-in-part patent
`application of
`
`Inventor(s): Daniel L. Flamm
`
`I hereby certify that this is being deposited with the
`United States Postal Service "Express Mail Post Office
`to Addressee" service under 37 CFR 1.10 on the date indicated
`above and is addressed to:
`
`Assistant Commissioner for Patents
`
`Washington, D.C. 20231
`
`For: PROCESS DEPENDING ON PLASMA DISCHARGES SUSTAINED BY INDUCTIVE CO
`
`ING
`
`[X] This application claims priority from each of the following Application Nos./filing dates:
`08/567,224
`/ December 4, 1995
`;
`—08/736,315
`
`]
`
`--This application claims the benefit of U.S. Provisional
`Please amend this application by adding the following before the first sentence:
`Application No. 60/
`, filed
`, the disclosure of which is incorporated by reference.--
`
`application.
`
`Enclosed are:
`[X] Patent Application (incl. 26 pages spec., _/ pages claims, 1 page abstract).
`X]
`{3
`sheet(s) of [ ] formal
`[X] informal drawing(s).
`] An assignmentof the invention to
`] A[ ] signed [] unsigned Declaration & Power of Attorney.
`] A verified statementto establish small entity status under 37 CFR 1.9 and 37 CFR 1.27 [ ] is enclosed [ ] was filed
`in the earliest of the above-identified patent application(s).
`A certified copy of a
`Information Disclosure Statement under 37 CFR 1.97.
`] A petition to extend time to respond in the parent application of this continuation-in-part application.
`{X] Postcard.
`
`] ]
`
`
`
`
`Pursuant to 37 CFR 1.53, Applicant requests deferral of thefiling fee until submission of the Missing Parts of Application.
`
`Telephone:
`(415) 326-2400
`16655\3-1-lapp.tm
`
`Respectfully submitted,
`TQWNSENDand TOWNSEND and CREW LLP
`
`
`an
`
`
`Richard T. Ogawa
`Reg. No.: 37,692
`Attorneys for Applicant
`
`

`

`TOWNSENDand TOWNSENDand CREW LLP
`Two Embarcadero Center, 8th Floor
`San Francisco, CA 94111-3834
`(415) 326-2400
`
`APPLICATION TRANSMITTAL
`
`Atty. Docket No. 16655-00031]
`
`“Express Mail" Label No. EM140585524US_
`
`Date ofDepositMay40,1497
`
`PATENT APPLICATION
`ASSISTANT COMMISSIONER FOR PATENTS
`Washington, D. C. 20231
`
`I hereby certify that this is being deposited with the
`United States Postal Service "Express Mail Post Office
`to Addressee" service under 37 CFR 1.10 on the date indicated
`above and is addressed to:
`
`Sir:
`Transmitted herewith for filing is the [ ] patent application,
`[ ] design patent application, [X] continuation-in-part patent
`application of
`
`Inventor(s): Daniel L. Flamm
`
`Assistant Commissioner for Patents
`~ Washington, D.C. 20231
`
`For: PROCESS DEPENDING ON PLASMA DISCHARGESSUSTAINED BY INDUCTIVE CO
`
`ING
`
`[X] This application claims priority from each of the following Application Nos./filing dates:
`08/567 ,224
`/ December 4, 1995
`;
`_08/736.315
`/_ October 23, 1996
`
`3
`
`/
`
` ]
`
`--This application claims the benefit of U.S. Provisional
`Please amend this application by adding the following before the first sentence:
`Application No. 60/
`; filed
`, the disclosure of which is incorporated by reference.--
`
`Patent Application (incl. _2& pages spec., _/ pages claims, 1 page abstract).
`13
`sheet(s) of [ ] formal
`[X] informal drawing(s).
`An assignmentof the invention to
`A[ ] signed [] unsigned Declaration & Power of Attorney.
`A verified statementto establish small entity status under 37 CFR 1.9 and 37 CFR 1.27 [] is enclosed [ ] was filed
`in the earliest of the above-identified patent application(s).
`A certified copy of a
`Information Disclosure Statement under 37 CFR 1.97.
`A petition to extend time to respond in the parent application of this continuation-in-part application.
`Postcard.
`
`application.
`
`Pursuant to 37 CFR 1.53, Applicant requests deferral of the filing fee until submission of the Missing Parts of Application.
`
`Telephone:
`(415) 326-2400
`16655\3-1-Lapp.tm
`
`Respectfully submitted,
`TOWNSENDand TOWNSENDand CREW LLP
`
`
`ID
`
`
`Richard T. Ogawa
`Reg. No.: 37,692
`Attorneys for Applicant
`
`

`

`16655-000311
`
`PATENT APPLICATION
`
`
`
`Inventor:
`
`Daniel L. Flamm,a citizen of the United States, residing at 476 Green
`View Drive, Walnut Creek, California 94596;
`
`
`
`Entity Status:
`
`Small
`
`TOWNSEND and TOWNSEND and CREW LLP
`Two Embarcadero Center, 8th Floor
`San Francisco, CA 94111-3834
`(415) 326-2400
`
`

`

`
`
`CROSS REFERENCES TO RELATED APPLICATIONS
`
`This application is a continuation-in-part of Application Serial No.
`08/736,315 filed October 23, 1996 which is a continuation of Application Serial No.
`08/567,224 filed December 4, 1995. All of these documents are hereby incorporated
`by reference for all purposes.
`
`BACKGROUND OF THE INVENTION
`
`This invention relates generally to plasma processing. More
`particularly, the invention is for plasma processing of devices using an inductive
`discharge. This invention is illustrated in an example with regard to plasma etching
`and resist stripping of semiconductor devices. The invention also is illustrated with
`regard to chemical vapor deposition (CVD) of semiconductor devices. But it will be
`recognized that the invention has a wider range of applicability. Merely by way of
`example, the invention also can be applied in other plasma etching applications, and
`deposition of materials such as silicon, silicon dioxide, silicon nitride, polysilicon,
`among others.
`
`Plasma processing techniques can occur in a variety of semiconductor
`manufacturing processes. Examples of plasma processing techniques occur in
`chemical dry etching (CDE), ion-assisted etching (IAE), and plasma enhanced
`chemical vapor deposition (PECVD), including remote plasma deposition (RPCVD)
`and ion-assisted plasma enhanced chemical vapor deposition IAPECVD). These
`plasma processing techniques often rely upon radio frequency power(rf) supplied to
`an inductive coil for providing powerto gas phase species in forming a plasma.
`Plasmas can be used to form neutral species(i.e., uncharged) for
`purposes of removing or forming films in the manufacture of integrated circuit
`devices. For instance, chemical dry etching generally depends on gas-surface
`reactions involving these neutral species without substantial ion bombardment.
`In other manufacturing processes, ion bombardmentto substrate
`
`10
`
`
`
`25
`
`30
`
`

`

`2
`
`surfaces is often undesirable. This ion bombardment, however, is known to have
`harmful effects on properties of material layers in devices and excessive ion
`bombardmentflux and energy can lead to intermixing of materials in adjacent device
`layers, breaking down oxide and "wear out," injecting of contaminative material
`formed in the processing environmentinto substrate material layers, harmful changes
`in substrate morphology (e.g. amophotization), etc.
`Ion assisted etching processes, however, rely upon ion bombardment
`to the substrate surface in defining selected films. But these ion assisted etching
`processes commonly have a lower selectivity relative to conventional CDE processes.
`Hence, CDEis often chosen whenhighselectivity is desired and ion bombardment
`to substrates are to be avoided.
`One commonly used chemical dry etching technique is conventional
`photoresist stripping, often termed ashing or stripping. Conventional resist stripping
`relies upon a reaction between a neutral gas phase species and a surface material
`layer, typically for removal. This reaction generally formsvolatile products with the
`surface material layer for its removal. The neutral gas phase species is formed by a
`plasma discharge. This plasma discharge can be sustained by a coil (e.g., helical
`coil, etc.) operating at a selected frequency in a conventional photoresist stripper. An
`example of the conventional photoresist stripper is a quarter-wave helical resonator
`stripper, which is described by U.S. Patent No. 4,368,092 in the name of Steinberg
`et al.
`
`Referring to the above, an objective in chemical dry etching is to
`reduce or even eliminate ion bombardment(or ion flux) to surfaces being processed
`to maintain the desired etching selectivity.
`In practice, however, it is often difficult
`to achieve using conventional techniques. These conventional techniques generally
`attempt to control ion flux by suppressing the amount of charged species in the
`plasma source reaching the process chamber. A variety of techniques for suppressing
`these charged species have been proposed.
`These techniques often rely upon shields, baffles, large separation
`distances between the plasma source and the chamber, orthe like, placed between the
`plasma source and the process chamber. The conventional techniques generally
`
`
`
`
`20
`
`25
`
`30
`
`

`

`3
`
`attempt to directly suppress charge density downstream of the plasma source by
`interfering with convective and diffusive transport of charged species. They tend to
`promote recombination of charged species by either increasing the surface area (e.g.,
`baffles, etc.) relative to volume, or increasing flow time, which relates to increasing
`
`the distance between the plasma source and the process chamber.
`
`These baffles, however, cause loss of desirable neutral etchant species
`
`as well. The baffles, shields, and alike, also are often cumbersome. Baffles, shields,
`
`or the large separation distances also cause undesirable recombinative loss of active
`
`species and sometimes cause radio frequency powerloss and other problems. These
`
`baffles and shields also are a potential source of particulate contamination, which is
`
`often damaging to integrated circuits.
`
`Baffles, shields, spatial separation, and alike, when used alone also are
`
`often insufficient to substantially prevent unwanted parasitic plasma currents. These
`
`plasma currents are generated between the wafer and the plasma source, or between
`
`the plasma source and walls of the chamber.
`
`It is commonly knownthat wheninitial
`
`charged species levels are present in an electrical field, the charged species are
`
`accelerated and dissociative collisions with neutral particles can multiply the
`
`concentration of charge to higher levels. If sufficient "seed" levels of charge and rf
`potentials are present, the parasitic plasma in the vicinity of the process wafer can
`reach harmful charge density levels.
`In some cases, these charge densities may be
`
`.
`
`similar to or even greater than plasma density within the source plasma region,
`
`thereby causing even more ion flux to the substrate.
`
`Charge densities also create a voltage difference between the plasma
`
`source and processing chamberor substrate support, which can have an additional
`
`10
`
`25
`
`deleterious effect. This voltage difference enhances electric fields that can accelerate
`
`extraction of charge from the plasma source. Hence, their presence often induces
`
`increased levels of charge to be irregularly transported from the plasma source to
`
`process substrates, thereby causing non-uniform ion assisted etching.
`
`Conventional ion assisted plasma etching, however, often requires
`
`30
`
`control and maintenance of ion flux intensity and uniformity within selected process
`
`limits and within selected process energy ranges. Control and maintenance of ion
`
`

`

`4
`
`flux intensity and uniformity are often difficult to achieve using conventional
`
`techniques. For instance, capacitive coupling between high voltage selections
`
`of the coil and the plasma discharge often cause high and uncontrollable plasma
`
`potentials relative to ground. It is generally understood that voltage difference
`
`between the plasma and ground can cause damaging high energy ion bombardmentof
`
`articles being processed by the plasma, as illustrated by U.S. Patent No. 5,234,529 in
`
`the name of Johnson.
`
`It is further often understood that rf component of the plasma
`
`potential varies in time since it is derived from a coupling to time varying rf
`
`excitation. Hence, the energy of charged particles from plasma in conventional
`
`inductive sources is spread over a relatively wide range of energies, which
`
`undesirably tends to introduce uncontrolled variations in the processing ofarticles by
`
`the plasma.
`
`Thevoltage difference between the region just outside of a plasma
`
`source and the processing chamber can be modified by introducing internal
`
`conductive shields or electrode elements into the processing apparatus downstream of
`
`the source. When the plasma potential is elevated with respect to these shield
`
`electrodes, however, there is a tendency to generate an undesirable capacitive
`
`discharge between the shield and plasma source. These electrode elements are often
`
`a source of contamination and the likelihood for contamination is even greater when
`
`
`
`20
`
`there is capacitive discharge (ion bombardment from capacitive discharge is a
`
`potential source of sputtered material). Contamination is damaging to the
`
`manufacture of integrated circuit devices.
`
`Another limitation is that the shield or electrode elements generally
`
`require small holes therein as structural elements. These small holes are designed to
`
`25
`
`allow gas to flow therethrough. The small holes, however, tend to introduce
`
`unwanted pressure drops and neutral species recombination. If the holes are made
`
`larger, the plasma from the source tends to survive transport through the holes and
`
`unwanted downstream charge flux will often result.
`
`In addition, undesirable
`
`discharges to these holes in shields can, at times, produce an even more undesirable
`
`30
`
`hollow cathode effect.
`
`In conventional helical resonator designs, conductive external shields
`
`

`

`5
`
`are interposed between the inductive power(e.g., coil, etc.) and walls of the vacuum
`
`vessel containing the plasma. A variety limitations with these external capacitive
`
`shielded plasma designs (e.g., helical resonator, inductive discharge, etc.) have been
`
`observed.
`
`In particular, the capacitively shielded design often produces plasmasthat
`
`are difficult to tune and even ignite. Alternatively, the use of unshielded plasma
`
`sources (€.g.,
`
`conventional quarter-wave resonator, conventional half-wave
`
`resonator, etc.) attain a substantial plasma potential from capacitive coupling to the
`coil, and hence are prone to create uncontrolled parasitic plasma currents to grounded
`surfaces. Accordingly, the use of either the shielded or the unshielded sources using
`conventional quarter and half-wave rf frequencies produce undesirable results.
`
`In many conventional plasma sources a means of cooling is required to
`maintain the plasma source and substrates being treated below a maximum
`temperature limit. Power dissipation in the structure causes heating and thereby
`increases the difficulty and expense of implementing effective cooling means.
`Inductive currents may also be coupled from the excitation coil into internal or
`
`capacitive shields and these currents are an additional source of undesirable power
`loss and heating. Conventional capacitive shielding in helical resonator discharges
`utilized a shield which was substantially split along the long axis of the resonator to
`
`lessen eddy current loss. However, such a shield substantially perturbs the resonator
`characteristics owing to unwanted capacitive coupling and current which flows from
`the coil to the shield. Since there are no general design equations, nor are properties
`currently known for resonators which are "loaded" with a shield along the axis,
`sources using this design must be sized and made to work bytrial anderror.
`In inductive discharges, it is highly desirable to be able to substantially
`control the plasma potential relative to ground potential, independent of input power,
`pressure, gas composition and other variables.
`In manycases,it is desired to have
`the plasma potential be substantially at ground potential (at least offset from ground
`potential by an amountinsignificantly different from the floating potential or intrinsic
`DC plasmapotential). For example, when a plasmasourceis utilized to generate
`neutral species to be transported downstream of the source for use in ashingresist on
`a semiconductor device substrate (a wafer or flat panel electronic display), the
`
`10
`
`25
`
`30
`
`

`

`6
`
`concentration and potential of charged plasma species in the reaction zone are
`
`desirably reduced to avoid charging damage from electron or ionic current from the
`
`plasma to the device. Whenthere is a substantial potential difference between plasma
`in the source and grounded surfaces beyond the source, there is a tendency for
`unwanted parasitic plasma discharges to form outside of the source region.
`Another undesirable effect of potential difference is the acceleration of
`ions toward grounded surfaces and subsequent impact of the energetic ions with
`surfaces. High energy ion bombardment maycause lattice damage to the device
`substrate being processed and may cause the chamber wall or other chamber materials
`
`In other plasma processing procedures,
`to sputter and contaminate device wafers.
`however, some ion bombardment may be necessary or desirable, as is the case
`particularly for anisotropic ion-induced plasma etching procedures (for a discussion
`of ion-enhanced plasma etching mechanisms See Flamm (Ch. 2,pp.94-183 in Plasma
`Etching, An Introduction, D. M. Manos and D.L. Flamm, eds., Academic Press,
`1989)). Consequently, uncontrolled potential differences, such as that caused by
`"stray" capacitive coupling from the coil of an inductive plasma source to the plasma,
`are undesirable.
`
`Referring to the above limitations, conventional plasma sources also
`have disadvantages when used in conventional plasma enhanced CVD techniques.
`These techniques commonly form a reaction of a gas composition in a plasma
`discharge. One conventional plasma enhanced techniquerelies upon ions aiding in
`rearranging andstabilizing the film, provided the bombardmentfrom the plasmais
`not sufficiently energetic to damage the underlying substrate or the growing film.
`Conventional resonators and other types of inductive discharges often produce
`parasitic plasma currents from capacitive coupling, which often detrimentally
`influences film quality, e.g., an inferior film, etc. These parasitic plasma currents
`are often uncontrollable, and highly undesirable. These plasma sources also have
`disadvantages in other plasma processing techniques such as ion-assisted etching, and
`others. Of course, the particular disadvantage will often depend upon the
`application.
`
`To clarify certain concepts used in this application, it will be
`
`10
`
`
`
`“20
`
`25
`
`30
`
`

`

`convenient to introduce these definitions.
`
`Ground (or ground potential): These terms are defined as a reference
`potential which is generally taken as the potential of a highly
`conductive shield or other highly conductive surface which surrounds
`the plasma source. To bea true ground shield in the sense ofthis
`definition, the RF conductance at the operating frequencyis often
`substantially high so that potential differences generated by current
`within the shield are of negligible magnitude compared to potentials
`intentionally applied to the various structures and elements of the
`plasma source or substrate support assembly. However, some
`realizations of plasma sources do not incorporate a shield or surface
`with adequate electrical susceptance to meetthis definition.
`In
`implementations where there is a surrounding conductive surface that
`is somewhatsimilar to a ground shield or ground plane, the ground
`potential is taken to be the fictitious potential which the imperfect
`grounded surface would have equilibrated to if it had zero high
`frequency impedance.
`In designs where there is no physical surface
`which is adequately configured or which does not have insufficient
`susceptance to act as a "ground" according to the abovedefinition,
`ground potential is the potential of a fictitious surface which is equi-
`potential with the shield or "ground" conductor of an unbalanced
`transmission line connection to the plasma sourceat its RF feed point.
`In designs where the plasma source is connected to an RF generator
`with a balanced transmission line RF feed, "ground" potential is the
`average of the driven feed line potentials at the point where the feed
`lines are coupled to the plasma source.
`
`Inductively Coupled Power: This term is defined as powertransferred
`to the plasma substantially by means of a time-varying magnetic flux
`which is induced within the volumecontaining the plasma source. A
`time-varying magnetic flux induces an electromotive force in accord
`with Maxwell's equations. This electromotive force induces motion by
`electrons and other charged particles in the plasma and thereby imparts
`energy to these particles.
`
`In most
`RF inductive power source and bias power supply:
`conventional inductive plasma source reactors, power is supplied to an
`inductive coupling element(the inductive coupling elementis often a
`multi-turn coil which abuts a dielectric wall containing a gas where the
`plasmais ignited at low pressure) by an rf power generator.
`
`Conventional Helical Resonator: Conventional helical resonator can
`be defined as plasma applicators. These plasma applicators have been
`designed and operated in multiple configurations, which were
`described in, for example, U.S. Patent No. 4,918,031 in the names of
`Flammet al., U.S. Patent No. 4,368,092 in the name of Steinberg et
`
`5
`
`10
`
`
`
`30
`
`35
`
`40
`
`45
`
`

`

`5
`
`10
`
`
`
`30
`
`8
`
`al., U.S Patent No. 5,304,282 in the name of Flamm, U.S. Patent No.
`5,234,529 in the name of Johnson, U.S. Patent No. 5,431,968 in the
`name of Miller, and others. In these configurations, one end of the
`helical resonator applicator coil has been grounded to its outer shield.
`In one conventional configuration, a quarter wavelength helical
`resonator section is employed with one end ofthe applicator coil
`grounded and the other end floating (i.e., open circuited). A trimming
`capacitance is sometimes connected between the grounded outer shield
`and the coil to "fine tune" the quarter wavestructure to a desired
`resonant frequency that is below the native resonant frequency without
`added capacitance.
`In another conventional configuration, a half-
`wavelength helical resonator section was employed in which both ends
`of the coil were grounded. The function of grounding the one or both
`ends of the coil was believed to be not essential, but advantageous to
`"stabilize the plasma operating characteristics" and "reduce the
`possibility of coupling stray current to nearby objects." See U.S.
`Patent No. 4,918,031.
`
`Conventional resonators have also been constructed in other
`geometrical configurations. For instance, the design of helical
`resonators with a shield of square cross section is described in Zverev
`et al., IRE Transactions on ComponentParts, pp. 99-110, Sept. 1961.
`Johnson (U.S. Patent No. 5,234,529) teaches that one end of the
`cylindrical spiral coil in a conventional helical resonator may be
`deformed into a planar spiral above the top surface of the plasma
`reactor tube. U.S. Patent No. 5,241,245 in the names of Barneset al.
`teach the use of conventional helical resonators in whichthespiral
`cylindrical coil is entirely deformed into a planar spiral arrangement
`with no helical coil component along the sidewalls of the plasma
`source (this geometry has often been referred to as a "transformer
`coupled plasma," termed a TCP).
`From the above it is seen that an improved technique, including a
`method and apparatus, for plasma processing is often desired.
`
`35SUMMARYOFTHEINVENTION
`
`The present invention provides a technique, including a method and
`apparatus, for fabricating a product using a plasma discharge. The present technique
`relies upon the controlof the instantaneous plasma AC potential to selectively control
`a variety of plasma characteristics. These characteristics include the amount of
`neutral species, the amountof charged species, overall plasma potential, the spatial
`extent and distribution of plasma density, the distribution of electrical current, and
`
`40
`
`

`

`9
`
`others. This technique can be used in applications including chemical dry etching
`(e.g., stripping, etc.), ion-enhanced etching, plasma immersion ion implantation,
`chemical vapor deposition and material growth, and others.
`In one aspect of the invention, a process for fabricating a productis
`provided. These products include a varieties of devices (e.g., semiconductor,flat
`panel displays, micro-machined structures, etc.) and materials, e.g., diamonds, raw
`materials, plastics, etc. The process includes steps of subjecting a substrate to a
`composition of entities. At least one of the entities emanates from a species
`generated by a gaseous discharge excited by a high frequency field in which the
`vector sum of phase and anti-phase capacitive coupled voltages (e.g., AC plasma
`voltage) from the inductive coupling structure substantially balances. This process
`providesfor a technique that is substantially free from stray or parasitic capacitive
`coupling from the plasma source to chamber bodies (e.g., substrate, walls, etc.) at or
`near groundpotential.
`
`In another aspect of the invention, another process for fabricating a
`product is provided. The processincludes steps of subjecting a substrate to a
`composition of entities. At least one of the entities emanates from a species
`generated by a gaseous discharge excited by a high frequency field in which the
`vector sum of phase and anti-phase capacitive coupled voltages from the inductive
`coupling structure is selectively maintained. This process provides for a technique
`that can selectively control the amountofcapacitive coupling to chamber bodies at or
`near groundpotential.
`
`A further aspect of the invention provides yet another process for
`fabricating a product. This process includes steps of subjecting a substrate to a
`composition of entities. At least one of the entities emanates from a species
`generated by a gaseous discharge excited by a high frequency field in which the
`vector sum of phase and anti-phase capacitive coupled voltages from the inductive
`coupling structure is selectively maintained. A further step ofselectively applying a
`voltage between theat least one ofthe entities in the plasma source and a substrate is
`provided. This process provides for a technique that can selectively control the
`amount of capacitive coupling to chamberbodies at or near ground potential, and
`
`10
`
`25
`
`30
`
`

`

`10
`
`provide for a driving voltage between the entities and a substrate.
`
`Another aspect of the invention provides another process for
`fabricating a product. The process comprises steps of subjecting a substrate to a
`composition of entities and using the resulting substrate for completion of the
`product. At least one of the entities emanates from a species generated by a gaseous
`discharge provided by a plasma applicator, e.g., a helical resonator, inductivecoil,
`transmission line, etc. This plasma applicator has an integral current driven by
`capacitive coupling of a plasma columnto elements with a selected potential greater
`than a surrounding shield potential substantially equal to capacitive coupling of the
`plasma column tosubstantially equal elements with a potential below shield potential.
`In a further aspect, the invention provides an apparatus for fabricating
`a product. The apparatus has an enclosure comprising an outer surface and an inner
`surface. The enclosure houses a gaseous discharge. The apparatus also includes a
`plasmaapplicator(e.g., helical coil, inductive coil, transmission line, etc.) disposed
`adjacent to the outer surface. A high frequency power source operably coupled to the
`plasmaapplicator is included. The high frequency power source provides high
`frequency to excite the gaseous discharge to provide at least one entity from a high
`frequency field in which the vector sum of phase and anti-phase capacitive current
`coupled from the inductive coupling structure is selectively maintained.
`In another aspect, the present invention provides an improved plasma
`discharge apparatus. This plasma discharge apparatus includes a plasma source, a
`plasma applicator (e.g., inductive coil, transmission line, etc.), and other elements.
`This plasma applicator provides a de-coupled plasma source. A wave adjustment
`circuit (e.g., RLC circuit, coil, transmission line, etc.) is operably coupled to the
`plasma applicator. The wave adjustment circuit can selectively adjust phase and anti-
`phasepotentials of the plasma from an rf power supply. This rf power supply is
`operably coupled to the wave adjustmentcircuit.
`
`The present invention achieves these benefits in the context of known
`process technology. However, a further understanding of the nature and advantages
`of the present invention may berealized by referenceto the latter portions of the
`specification and attached drawings.
`
`10
`
`25
`
`30
`
`

`

`11
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Fig. 1 is a simplified diagram of a plasma etching apparatus according
`to the present invention;
`
`Figs. 2A-2Eare simplified configurations using wave adjustment
`circuits according to the present invention;
`Fig. 3 is a simplified diagram of a chemical vapor deposition apparatus
`according to the present invention;
`
`Fig. 4 is a simplified diagram ofa stripper according to the present
`
`invention;
`
`Figs. 5A-5C are more detailed simplified diagramsof a helical
`resonator according to the present invention;
`Fig. 6 is a conventional quarter-wave helical resonator plasma etching
`apparatus with stray plasma whichresults from the coupling in the conventional
`design;
`
`Fig. 7 is a simplified diagram of the rf voltagedistribution along the
`coil of the Fig. 6 apparatus;
`Fig. 8 is a simplified top-view diagram ofa stripping apparatus
`according to the present experiments; and
`Fig. 9 is a simplified side-view diagram of a stripping apparatus
`according to the present experiments.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`Fig. 1 is a simplified diagram of a plasma etch apparatus 10 according
`to the present invention. This etch apparatus is provided with an inductive
`applicator, e.g., inductive coil. This etch apparatus depicted, however, is merely an
`illustration, and should notlimit the scope of the claims as defined herein. One of
`ordinary skilled in the art may implement the present invention with other treatment
`chambers andthe like.
`
`The etch apparatus includes a chamber 12, a feed source 14, an
`exhaust 16, a pedestal 18, an inductive applicator 20, a radio frequen