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`WARNING: The information disclosed herein may be restricted. Unaytl16rized disclosure may be prohibited
`by the United States Code Title 35, Sections 122, 18:t"'and 368. Possession outside the U.S.
`Patent & Trademark Office is restricted to authorized employees and contractors only.
`
`',··~~ .. -'•
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`

`
`United States Patent [19]
`Flamm
`
`US006017221A
`[11] Patent Number:
`[45] Date of Patent:
`
`6,017,221
`Jan. 25, 2000
`
`[54] PROCESS DEPENDING ON PLASMA
`DISCHARGES SUSTAINED BY INDUCTIVE
`COUPLING
`
`5,431,968
`5.534.231
`5,637,961
`
`7/1995 Miller et al..
`7/1996 savas.
`6/1997 Ishii et al. .
`
`[76] Inventor: Daniel L. Flamm, 476 Green View Dr.,
`Walnut Creek, Calif. 94596
`
`[21] App1_NO_;08/866,040
`
`[221
`
`Filed?
`
`May 30! 1997
`
`Related US. Application Data
`
`[63]
`
`Continuation-in-part of application No. 08/736,315, Oct. 23,
`1996, abandoned, which is a continuation of application No.
`08/567,224’ Dec 4’ 1995’ abandoned~
`7
`[51] Int. Cl. ................................................... .. H01L 21/00
`[52] US. Cl. ........................ .. 437/225; 437/228; 437/233;
`156/643; 156/192.25; 204/192.32
`[58] Field of Search .......................... .. 118/501; 156/643,
`156/345, 646, 659.1; 219/12141, 121.44;
`204/1921, 19212, 19225; 427/12; 216/2;
`437/225, 228, 233
`
`OTHER PUBLICATIONS
`
`Asmussen et al., “The Design of a Microwave Plasma
`Cavity,” Pr0c. ofIEEE, 62(1):109—117 (Jan. 1974).
`Eckert, “The Hundred Year History of Induction Dis
`charges,” 2”“Ann. Int’l Conf Plasma Chem. Tech., (1984).
`Fossheim et al., “Broadband tguning of helical resonant
`cavitites,” J. Phys. E. Sci. Instrum, 11:892—893 (1978).
`NiaZi et al. “Operation of a helical resonator plasma source,”
`Plasma Sources Sci. TechnoL, 3:482—495 (1994).
`Roppel et al., “Low temperature oxidation of silicon using a
`microwave plasma disk source,” J. Vac. sci. TechnoL,
`B4(1):295—298 (Jan/Feb. 1986).
`Zverev et a1‘, “Realization of a Filter With Helical COmpO_
`nents,” [RE THU“ On Component Parts) pp 99_11(), (Sap~
`1961)
`
`Primary Examiner—Laurie Scheiner
`Attorney, Agent, Or Firm—ToWnsend and TOWnScnd and
`CreW LLP
`
`[561
`
`References Cited
`
`[571
`
`ABSTRACT
`
`Us‘ PATENT DOCUMENTS
`
`3/1975 Gabriel .
`3,873,884
`1/1983 Steinberg et a1- -
`4,368,092
`4/1990 Flamm ct a1~ -
`4,918,031
`7/1990 Asmussen et al. ................... .. 156/643
`4,943,345
`8/1993 Johnson '
`5’234’529
`8/1993 Barnes et al. .
`5,241,245
`4/1994 Flamm .
`5,304,282
`5,361,016 11/1994 Ohkawa et al. ................. .. 315/111.41
`
`A process for fabricating a product 28, 119. The process
`comprises the steps of subjecting a substrate to a composi
`tion of entities, at least one of the entities emanating from a
`species generated by a gaseous discharge excited by a high
`frequency ?eld in which the vector sum of phase and
`anti-phase capacitive coupled voltages from the inductive
`coupling structure substantially balances.
`
`7 Claims, 13 Drawing Sheets
`
`LAM Exh 1009-pg 3
`
`

`
`U.S. Patent
`
`Jan. 25,2000
`
`Sheet 1 0f 13
`
`6,017,221
`
`FIG. 1
`
`LAM Exh 1009-pg 4
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`

`
`U.S. Patent
`
`Jan. 25,2000
`
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`6,017,221
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`U.S. Patent
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`Jan. 25,2000
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`Sheet 3 0f 13
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`6,017,221
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`U.S. Patent
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`Jan. 25,2000
`
`Sheet 4 0f 13
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`6,017,221
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`LAM Exh 1009-pg 7
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`U.S. Patent
`
`Jan. 25,2000
`
`Sheet 5 0f 13
`
`6,017,221
`
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`
`LAM Exh 1009-pg 8
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`U.S. Patent
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`Jan. 25,2000
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`6,017,221
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`Jan. 25,2000
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`Jan. 25,2000
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`Jan. 25,2000
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`Jan. 25,2000
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`Jan. 25, 2000
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`Jan. 25,2000
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`U.S. Patent
`
`Jan. 25,2000
`
`Sheet 13 of 13
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`6,017,221
`
`LAM Exh 1009-pg 16
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`LAM Exh 1009-pg 16
`
`

`
`1
`PROCESS DEPENDING ON PLASMA
`DISCHARGES SUSTAINED BY INDUCTIVE
`COUPLING
`
`CROSS REFERENCES TO RELATED
`APPLICATIONS
`
`This application is a continuation-in-part of application
`Ser. No. 08/736,315 ?led Oct. 23, 1996, noW abandoned,
`Which is a continuation of application Ser. No. 08/567,224
`?led Dec. 4, 1995, noW abandoned. 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 mate
`rials 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 fre
`quency poWer (rf) supplied to an inductive coil for providing
`poWer to gas phase species in forming a plasma.
`Plasmas can be used to form neutral species (i.e.,
`uncharged) for purposes of removing or forming ?lms 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 bombardment to
`substrate surfaces is often undesirable. This ion
`bombardment, hoWever, is knoWn to have harmful effects on
`properties of material layers in devices and excessive ion
`bombardment ?ux 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 environment into 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 de?ning selected
`?lms. But these ion assisted etching processes commonly
`have a loWer selectivity relative to conventional CDE pro
`cesses. Hence, CDE is often chosen When high selectivity 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 reac
`tion betWeen a neutral gas phase species and a surface
`material layer, typically for removal. This reaction generally
`forms volatile products With the surface material layer for its
`removal. The neutral gas phase species is formed by a
`
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`
`2
`plasma discharge. This plasma discharge can be sustained by
`a coil (e.g., helical coil, etc.) operating at a selected fre
`quency in a conventional photoresist stripper. An example of
`the conventional photoresist stripper is a quarter-Wave heli
`cal resonator stripper, Which is described by US. Pat. 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 ?ux) to surfaces being processed to maintain the desired
`etching selectivity. In practice, hoWever, it is often difficult
`to achieve using conventional techniques. These conven
`tional techniques generally attempt to control ion ?ux by
`suppressing the amount of charged species in the plasma
`source reaching the process chamber. A variety of tech
`niques 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, or the like, placed betWeen the plasma source and
`the process chamber. The conventional techniques generally
`attempt to directly suppress charge density doWnstream of
`the plasma source by interfering With convective and diffu
`sive 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 increas
`ing ?oW time, Which relates to increasing the distance
`betWeen the plasma source and the process chamber.
`These baf?es, hoWever, cause loss of desirable neutral
`etchant species as Well. The baffles, shields, and alike, also
`are often cumbersome. Baf?es, shields, or the large separa
`tion distances also cause undesirable recombinative loss of
`active species and sometimes cause radio frequency poWer
`loss and other problems. These baf?es and shields also are
`a potential source of particulate contamination, Which is
`often damaging to integrated circuits.
`Baf?es, shields, spatial separation, and alike, When used
`alone also are often insuf?cient 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 knoWn that When initial charged species levels
`are present in an electrical ?eld, the charged species are
`accelerated and dissociative collisions With neutral particles
`can multiply the concentration of charge to higher levels. If
`suf?cient “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 ?ux to the substrate.
`Charge densities also create a voltage difference betWeen
`the plasma source and processing chamber or substrate
`support, Which can have an additional deleterious effect.
`This voltage difference enhances electric ?elds 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 control and maintenance of ion ?ux intensity and
`uniformity Within selected process limits and Within selected
`process energy ranges. Control and maintenance of ion ?ux
`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
`
`LAM Exh 1009-pg 17
`
`

`
`3
`discharge often cause high and uncontrollable plasma poten
`tials relative to ground. It is generally understood that
`voltage difference betWeen the plasma and ground can cause
`damaging high energy ion bombardment of articles being
`processed by the plasma, as illustrated by US. Pat. No.
`5,234,529 in the name of Johnson. It is further often under
`stood 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 of
`articles by the plasma.
`The voltage difference betWeen the region just outside of
`a plasma source and the processing chamber can be modi?ed
`by introducing internal conductive shields or electrode ele
`ments 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 contami
`nation is even greater When 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 alloW gas to How there
`through. 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 ?ux Will often result. In addition, unde
`sirable discharges to these holes in shields can, at times,
`produce an even more undesirable holloW cathode effect.
`In conventional helical resonator designs, conductive
`external shields are interposed betWeen the inductive poWer
`(e.g., coil, etc.) and Walls of the vacuum vessel containing
`the plasma. Avariety limitations With these external capaci
`tive shielded plasma designs (e.g., helical resonator, induc
`tive discharge, etc.) have been observed. In particular, the
`capacitively shielded design often produces plasmas that are
`dif?cult to tune and even ignite. Alternatively, the use of
`unshielded plasma sources (e.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 dif?culty and expense of implementing effec
`tive 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 substan
`tially perturbs the resonator characteristics oWing to
`unWanted capacitive coupling and current Which ?oWs from
`the coil to the shield. Since there are no general design
`
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`
`4
`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 by trial
`and error.
`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 com
`position and other variables. In many cases, it is desired to
`have the plasma potential be substantially at ground poten
`tial (at least offset from ground potential by an amount
`insigni?cantly different from the ?oating potential or intrin
`sic DC plasma potential). For example, When a plasma
`source is utiliZed to generate neutral species to be trans
`ported doWnstream of the source for use in ashing resist on
`a semiconductor device substrate (a Wafer or ?at panel
`electronic display), the 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. When there is a
`substantial potential difference betWeen plasma in the source
`and grounded surfaces beyond the source, there is a ten
`dency 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 subse
`quent impact of the energetic ions With surfaces. High
`energy ion bombardment may cause lattice damage to the
`device substrate being processed and may cause the chamber
`Wall or other chamber materials to sputter and contaminate
`device Wafers. In other plasma processing procedures,
`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 com
`monly form a reaction of a gas composition in a plasma
`discharge. One conventional plasma enhanced technique
`relies upon ions aiding in rearranging and stabiliZing the
`?lm, provided the bombardment from the plasma is not
`suf?ciently energetic to damage the underlying substrate or
`the groWing ?lm. Conventional resonators and other types of
`inductive discharges often produce parasitic plasma currents
`from capacitive coupling, Which often detrimentally in?u
`ences ?lm quality, e.g., an inferior ?lm, etc. These parasitic
`plasma currents are often uncontrollable, and highly unde
`sirable. 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 convenient to introduce these de?nitions.
`Ground (or ground potential): These terms are de?ned as
`a reference potential Which is generally taken as the poten
`tial of a highly conductive shield or other highly conductive
`surface Which surrounds the plasma source. To be a true
`ground shield in the sense of this de?nition, the RF con
`ductance at the operating frequency is often substantially
`high so that potential differences generated by current Within
`the shield are of negligible magnitude compared to poten
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`tials intentionally applied to the various structures and
`elements of the plasma source or substrate support assembly.
`HoWever, some realiZations of plasma sources do not incor
`porate a shield or surface With adequate electrical suscep
`tance to meet this de?nition. In implementations Where there
`is a surrounding conductive surface that is someWhat similar
`to a ground shield or ground plane, the ground potential is
`taken to be the ?ctitious 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 con?gured or Which
`does not have insuf?cient susceptance to act as a “ground”
`according to the above de?nition, ground potential is the
`potential of a ?ctitious surface Which is equi-potential With
`the shield or “ground” conductor of an unbalanced trans
`mission line connection to the plasma source at 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 de?ned as poWer
`transferred to the plasma substantially by means of a time
`varying magnetic ?uX Which is induced Within the volume
`containing the plasma source. A time-varying magnetic ?uX
`induces an electromotive force in accord With MaXWell’s
`equations. This electromotive force induces motion by elec
`trons and other charged particles in the plasma and thereby
`imparts energy to these particles.
`RF inductive poWer source and bias poWer supply: In
`most conventional inductive plasma source reactors, poWer
`is supplied to an inductive coupling element (the inductive
`coupling element is often a multi-turn coil Which abuts a
`dielectric Wall containing a gas Where the plasma is ignited
`at loW pressure) by an rf poWer generator.
`Conventional Helical Resonator: Conventional helical
`resonator can be de?ned as plasma applicators. These
`plasma applicators have been designed and operated in
`multiple con?gurations, Which Were described in, for
`example, US. Pat. No. 4,918,031 in the names of Flamm et
`al., US. Pat. No. 4,368,092 in the name of Steinberg et al.,
`US. Pat. No. 5,304,282 in the name of Flamm, U.S. Pat. No.
`5,234,529 in the name of Johnson, US. Pat. No. 5,431,968
`in the name of Miller, and others. In these con?gurations,
`one end of the helical resonator applicator coil has been
`grounded to its outer shield. In one conventional
`con?guration, a quarter Wavelength helical resonator section
`is employed With one end of the applicator coil grounded
`and the other end ?oating (i.e., open circuited). A trimming
`capacitance is sometimes connected betWeen the grounded
`outer shield and the coil to “?ne tune” the quarter Wave
`structure to a desired resonant frequency that is beloW the
`native resonant frequency Without added capacitance. In
`another conventional con?guration, a half-Wavelength heli
`cal 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 character
`istics” and “reduce the possibility of coupling stray current
`to nearby objects.” See US. Pat. No. 4,918,031.
`Conventional resonators have also been constructed in
`other geometrical con?gurations. For instance, the design of
`helical resonators With a shield of square cross section is
`described in Zverev et al., IRE Transactions on Component
`Parts, pp. 99—110, Sept. 1961. Johnson (US. Pat. No.
`5,234,529) teaches that one end of the cylindrical spiral coil
`in a conventional helical resonator may be deformed into a
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`planar spiral above the top surface of the plasma reactor
`tube. U.S. Pat. No. 5,241,245 in the names of Barnes et al.
`teach the use of conventional helical resonators in Which the
`spiral 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.
`
`SUMMARY OF THE INVENTION
`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
`control of the instantaneous plasma AC potential to selec
`tively control a variety of plasma characteristics. These
`characteristics include the amount of neutral species, the
`amount of charged species, overall plasma potential, the
`spatial eXtent and distribution of plasma density, the distri
`bution of electrical current, and 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
`product is provided. These products include a varieties of
`devices (e.g., semiconductor, ?at panel displays, micro
`machined structures, etc.) and materials, e.g., diamonds, raW
`materials, plastics, etc. The process includes steps of sub
`jecting 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 ?eld in Which
`the vector sum of phase and anti-phase capacitive coupled
`voltages (e.g., AC plasma voltage) from the inductive cou
`pling structure substantially balances. This process provides
`for 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 ground
`potential.
`In another aspect of the invention, another process for
`fabricating a product is provided. 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 ?eld 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 amount of capacitive coupling to
`chamber bodies at or near ground potential.
`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 ?eld in Which
`the vector sum of phase and anti-phase capacitive coupled
`voltages from the inductive coupling structure is selectively
`maintained. A further step of selectively applying a voltage
`betWeen the at least one of the entities in the plasma source
`and a substrate is provided. This process provides for a
`technique that can selectively control the amount of capaci
`tive coupling to chamber bodies at or near ground potential,
`and 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
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`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, inductive coil, transmission line, etc. This
`plasma applicator has an integral current driven by capaci
`tive coupling of a plasma column to elements With a selected
`potential greater than a surrounding shield potential sub
`stantially equal to capacitive coupling of the plasma column
`to substantially 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 com
`prising an outer surface and an inner surface. The enclosure
`houses a gaseous discharge. The apparatus also includes a
`plasma applicator (e.g., helical coil, inductive coil, trans
`mission line, etc.) disposed adjacent to the outer surface. A
`high frequency poWer source operably coupled to the plasma
`applicator 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 ?eld 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 dis
`charge apparatus includes a plasma source, a plasma appli
`cator (e.g., inductive coil, transmission line, etc.), and other
`elements. This plasma applicator provides a de-coupled
`plasma source. AWave adjustment circuit (e. g., RLC circuit,
`coil, transmission line, etc.) is operably coupled to the
`plasma applicator. The Wave adjustment circuit can selec
`tively adjust phase and anti-phase potentials of the plasma
`from an rf poWer supply. This rf poWer supply is operably
`coupled to the Wave adjustment circuit.
`The present invention achieves these bene?ts in the
`context of knoWn process technology. HoWever, a further
`understanding of the nature and advantages of the present
`invention may be realiZed by reference to the latter portions
`of the speci?cation and attached draWings.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a simpli?ed diagram of a plasma etching
`apparatus according to the present invention;
`FIGS. 2A—2E are simpli?ed con?gurations using Wave
`adjustment circuits according to the present invention;
`FIG. 3 is a simpli?ed diagram of a chemical vapor
`deposition apparatus according to the present invention;
`FIG. 4 is a simpli?ed diagram of a stripper according to
`the present inv