United States Patent
`Hauzer et al.
`[45] Date of Patent:
`Apr. 26, 1994
`
`[19]
`
`[11] Patent Number:
`
`5,306,407
`
`|l|||l||||||||lllllllllllllIlllllllllIllllIllllllllllllllllllllllllllllllll
`USO05306407A
`
`[52] U.S. C1. ........................ .. 204/192.38; 204/ 192.16;
`204/ 192.3; 204/298.41; 427/530; 427/580
`[58] Field of Search ...................... 204/192.38, 298.41,
`204/192.16, 192.3; 427/580, 523, 524, 530
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,877,505 10/1989 Bergmann ...................... 204/192.38
`5,037,517
`8/1991 Randhawa ... ... .
`... ... 204/192.15
`5,160,595 11/1992 Hauzer et al. ........... .. 204/192.38
`5,234,561
`8/1993 Randhawa et al.
`............ 204/192.38
`
`
`
`FOREIGN PATENT DOCUMENTS
`
`2-34775 2/1990 Japan .............................. 204/298.14
`
`Primary Examiner——Aaron Weisstuch
`— Attorney, Agent, or Fz'rm—-Townsend and Townsend
`Khourie and Crew
`
`[57]
`
`ABSTRACT
`
`A method and an apparatus for coating substrates is
`described in which the layer to be applied is produced
`by the condensing particles of a plasma generated by a
`gas discharge which are incident on the substrates. Both
`an arc discharge vaporization coating process and a
`cathode sputtering coating process are effected in the
`same apparatus, and the arc discharge vaporization
`process is carried out before the cathode sputtering
`process.
`
`28 Claims, 9 Drawing Sheets
`
`[54] METHOD AND APPARATUS FOR COATING
`SUBSTRATES
`
`[75]
`
`Inventors: Franciscus J. M. Hauzer;
`Wolf-Dieter Munz; Hans Veltrop, all
`of Venlo, Netherlands; Harald
`Wesemeyer, deceased, late of
`Hanger-Varnamo; Beate Wesemeyer,
`heiress, Kleinfischbach, both of
`Sweden
`
`[73] Assignee: Hauzer Holding BV, AF Venlo,
`Netherlands
`
`[211 App]. No.:
`
`654,626
`
`[22] PCT Filed:
`
`Jun. 27, 1990
`
`[86] PCT No.:
`
`PCT/EP90/01032
`
`§ 371 Date:
`
`Jul. 29, 1992
`
`§ 102(e) Date:
`
`Jul. 29, 1992
`
`[87] PCT Pub. No.: W091/00374
`
`PCT Pub. Date: Jan. 10, 1991
`
`[30]
`
`Foreign Application Priority Data
`
`Jun. 27, 1989 [EP]
`Dec. 19, 1989 [DE]
`
`........ 891ll705.3
`European Pat. Off.
`Fed. Rep. of Germany ..... .. 3941918
`
`[51]
`
`Int. C1.5 .................... .. c23c 14/32; c23c 14/34;
`C23C 14/43
`
`GILLETTE 1016
`
`\\uuuuu\uuN\nsu\\\n\uu\\\u\ 1I
`
`GILLETTE 1016
`
`

`
`U.S. Patent
`
`Apr. 26, 1994
`
`Sheet 1 of_9
`
`5,306,407
`
`Fig.1
`
`0
`
`80eV
`
`200eV
`
`E
`
`

`
`U.S. Patent
`
`Apr. 26, 1994
`
`Sheet 2 of 9
`
`5,306,407
`
`Fig. 2A (PRIOR ART)
`2
`
`.-.____.___:._..
`
` 5
`
`ov.....-soov
`
`1.
`
`ov-———————--————ov
`
`
`
`WIIIIIIIAVIIIIIIIIIIIIIIIA
`
`
`
`Fig-. 2B (PRIOR ART)
`
`

`
`U.S. Patent
`
`Apr. 26, 1994
`
`Sheet 3 of 9
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`5,306,407
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`

`
`U.S. Patent
`
`Apppppppp94
`
`Sheet 4 of 9
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`5,306,407
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`
`
`
`
`
`
`I/ 5
`
`

`
`U.S. Patent
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`5,306,407
`
`

`
`U.S. Patent
`
`Apr. 26, 1994
`
`Sheet 6 of 9
`
`5,306,407
`
`~ Fig .7
`
`(1 10pm)
`
`l0,05.....0,2pm)
`
`TiN
`
`TiN
`
`SUBSTRATE
`
`

`
`U.S. Patent
`
`Apr. 26, 1994
`
`Sheet 7 of 9
`
`5,306,407
`
`Fig.8
`
`

`
`U.S. Patent
`
`Apr. 26, 1994
`
`Sheet 8 of 9
`
`5,306,407
`
`{I 10pm)
`
`TiN
`
`SUBSTRATE
`
`

`
`U.S. Patent
`
`Apr. 26, 1994
`
`Sheet 9 of 9
`
`5,306,407
`
`Fig.10
`
`

`
`1
`
`5,306,407
`
`2
`
`METHOD AND APPARATUS FOR COATING
`SUBSTRATES
`
`METHOD AND APPARATUS OF COATING
`SUBSTRATES
`
`5
`
`1. Field of the Invention
`
`OBJECT OF THE INVENTION
`
`An object of the invention is to develop a method
`which, on the one hand, ensures the deposition of layers
`which are as free as possible of defects and which are
`simultaneously well bonded, i.e. which are of high qual-
`ity layers, and which, on the other hand, offers adequate
`possibilities for ideally and precisely matching the layer
`growth to the required circumstances through a suitable
`choice of the deposition parameters.
`
`SUMMARY OF THE INVENTION
`
`This object is accomplished in accordance with the
`invention in that both an arc discharge vaporization
`process and a cathode sputtering process are performed,
`with the arc discharge vaporization being carried out
`before the cathode sputtering; i.e. in the first phase of
`the coating process, are vaporization is used and the
`coating is then continued or terminated by means of
`cathode sputtering.
`As a result of the arc discharge vaporization which
`‘precedes the cathode sputtering, a transition layer is
`generated on the substrate surface with highly energetic
`ions which ensures a good bond of the layer to be ap-
`plied on the substrate, whereas, during the subsequent
`cathode sputtering, it is possible to sensitively control
`both the speed of condensation at low particle energy
`over wide ranges, corresponding to the desired crystal
`growth and the desired crystal structure of the layer to
`be applied, and also the bias voltage at the substrate. As
`a result of the short mean free path of the vaporized
`particles a uniform thickness distribution of the layer
`arises, even around the corners.
`The cathode sputtering can be carried out such that
`the vapor of the cathode material and also the gas atoms
`which participate in the cathode sputtering can be ion-
`ized to a substantially higher degree in the space be-
`tween the cathode and the substrate or substrates with
`the aid of magnetic fields, which are additionally pro-
`vided as compared with customary known methods of
`cathode sputtering, such as DC sputtering or magne-
`tron sputtering, whereby a dense layer deposition is
`made possible. This is achieved by the scattering fields
`of specially mounted magnetic arrangements, which
`consist in particular of coils, which can be formed in
`accordance with the known principles of magnetic field
`assisted sputtering, and of the imbalanced magnetron
`(see the literature references 1-6).
`As the major portion of the particles which condense
`on the substrate during arc discharge vaporization is
`ionized, the kinetic energies can, for example, be advan-
`tageously controlled without problem by means of a
`negative bias on the substrate. With the combination in
`accordance with the invention of arc discharge vapori-
`zation and cathode sputtering,
`in particular cathode
`sputtering by means of an imbalanced magnetron, the
`advantages of the two coating methods, namely the
`good bond strength and high layer quality which can be
`achieved, are exploited in an ideal manner without hav-
`ing to tolerate the above describeddisadvantages of the
`individual methods.
`
`The substrate is preferably first bombarded during
`the arc discharge vaporization process with Ti ions of
`optimized energy and corresponding ion current den-
`sity such that the substrate surface is cleaned by ion
`etching, i.e. is partly removed in a known manner. The
`high ion energy required for this surface cleaning can be
`generated relatively easily, for example by the applica-
`
`15
`
`25
`
`30
`
`The invention relates to a method of coating sub-
`strates in which the layer to be applied is produced by 10
`condensing particles of a plasma generated by means of
`a gas discharge which are incident on the substrates.
`The invention further relates to an apparatus for car-
`rying out the method.
`2. Background of the Invention
`The technology of surface treatment and the produc-
`tion of thin films has become extremely significant in
`recent years, particularly with respect to its industrial
`application. The numerous known vacuum methods for
`the production of thin films or for the treatment of 20
`material surfaces primarily include methods which re-
`late to vaporization in furnaces, boats, and crucibles,
`etc. In these methods the vaporization takes place for
`example through electrical heating, or by electron bom-
`bardment by means of an anodic or cathodic are, or by
`eddy current heating of conductive material in an in-
`' duced AC field. Moreover, the large area sputtering of
`cathodes is known in various embodiments of cathode
`sputtering, with or without magnetic enhancement of
`the ionization in the DC or AC glow discharge.
`In the known and customary ion assisted vaporization
`methods the kinetic energies of the atoms, ions and/or
`particles which are incident on the substrate are distrib-
`uted such that the highlyenergetic particles create de-
`fects in the crystal lattice of the condensing layer which
`lead to compressive stresses and embrittlement of the
`layer, or trigger effects which lead to an undesired
`reverse sputtering or resputtering of the condensing
`layer. On the other hand, the incident particles of lower
`energy often hardly attain the kinetic energy required at
`the surface to ensure a homogeneous layer build-up. A
`particularly broad and therefore unfavorable distribu-
`tion of the kinetic energies of the atoms and ions which
`are incident on the substrate is present with are vaporiz-
`ers in particular. Moreover, macroparticles,
`termed
`“droplets”, frequently arise with the various forms of
`arc vaporizers and can be extremely disturbing if a
`corrosion resistant material coating is required, or if the
`coefficient of friction of the layer material is intended to 50
`be particularly low.
`.
`With cathode sputtering, the low concentration of
`ionized particles compared with are vaporization is
`unfavorable, particularly in the direct environment of
`the substrates to be coated. This frequentlyleads to the 55
`condensing layers not being sufficiently dense, particu-
`larly when depositing layers of high melting point such
`as is the case with hard material coatings.
`Moreover, it has been shown that layers deposited by
`means of cathode sputtering are inferior with respect to
`bond strength to those deposited by are vaporization.
`On the other hand, with cathode sputtering, it is possi-
`ble to precisely set the kinetic energy of the incident
`ionized particles in the range of some few electron
`volts, for example 10 eV up to 1000 eV and more,
`through a suitable choice of the negative substrate bias,
`whereas the majority of the non-ionized atoms have a
`kinetic energy which is typically smaller than 10 eV.
`
`35
`
`45
`
`65
`
`

`
`3
`tion of a negative substrate bias in the range from 1500
`V to 2000 V.
`
`5,306,407
`
`The transition zone which is important for the inven-
`tive combination of arc discharge vaporization and
`cathode sputtering is subsequently likewise formed with
`the aid of arc discharge vaporization in the region di-
`rectly beneath the substrate surface. For this, the fact is
`exploited that the multiply ionized Ti-atoms produced
`during arc discharge vaporization can be implanted into
`the substrate surface under certain conditions. For this
`purpose the energy of the Ti-ions must, on the one
`hand, be sufficiently high, but on the other hand, not too
`high in order to avoid the above described etching
`process being initiated. This can be achieved, for exam-
`ple, with substrates of differently alloyed steels, when
`the negative substrate bias potential lies in the region
`between 1000 and 1500 V, preferably between 1100 and
`1200 V. In the case of iron containing substrates, Ti-Fe
`mixed crystals then form, by way of example, and en-
`sure a particularly advantageous anchoring of a TiN
`layer which, for example, grows during coating. Similar
`favorable results can be achieved if one uses Zr-, I-If-,
`Cr-, Ta-, Nb or V-ions for the pretreatment in place of
`Ti-ions. In these cases a zone of, for example, 200 to-
`4005; thickness and rich in mixed crystals first forms
`directly beneath the substrate surface, whereas a diffu-
`sion profile of the implanted foreign ions occurs beneath
`it which extends into the substrate thickness to a depth
`of 1500 to 2000A. This transition layer then brings
`about a support function of, for example, the very hard
`and relatively brittle TiN coating during mechanical
`loading when the ion energy, for example, of the Ti-
`vapor, is correspondingly optimized.
`The continuation of the coating process can be ef-
`fected in accordance with two methods:
`On the one hand, the negative bias at the substrate
`can be reduced while retaining the are discharge vapor-
`ization until a majority of the metal atoms and ions
`arriving at the substrate condense in the presence of
`nitrogen atoms and ions. This is, for example, the case
`when the negative substrate bias lies in the range from
`r 10 to 200 V, preferably between 50 and l00 V. The
`coating is then interrupted when, for example, up to
`20% of the desired layer thickness of, for example, TiN
`has been achieved. The process is then switched over to
`cathode sputtering.
`On the other hand, an even better design of the transi-
`tion from the substrate to the coating layer can be
`brought about if one, directly after manufacturing the
`transition layer by means of arc discharge vaporization,
`directly switches over the ion implantation to coating
`by means of cathode sputtering, particularly by using an
`imbalanced magnetron. In the case of deposition of, for
`example, TiN, it is advantageous to apply a negative
`substrate bias voltage during cathode sputtering in the
`range from 40 V to 200 V, preferably 50.-+:225 V. In
`doing so it should be ensured that the ion bombardment
`is carried out with an ion current density greater than 2
`mA/cmz in order to attain an adequate layer thickness
`(see literature reference 7).
`The processes of arc discharge vaporization and cath-
`ode sputtering can be carried out from the same cath-
`ode. It is, however, also possible to use separate or
`respective cathodes for the two process steps. This
`leads, on the one hand, to the system concept becoming
`more expensive but, on the other hand, also opens the
`possibility of being able to construct the transition layer
`with materials which differ from the actual coating.
`
`l0
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`65
`
`4
`An apparatus for carrying out the method in accor-
`dance with the invention includes a chamber which
`receives the respective working gas, a substrate holder
`arranged in the chamber, and various electrical circuits
`which are required to carry out the different method
`steps. The chamber which is used is in this arrangement
`is constructed such that it can be pumped out with
`customary vacuum pumps to 10'5 mbar. The chamber
`is electrically grounded.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention will now be explained in the following
`in more detail with reference to the drawing in which
`are shown:
`
`FIG. 1 is a diagram of the typical distribution of the
`kinetic energies of the particles which are incident on
`the substrate when coating a substrate by means of a
`customary arc discharge vaporization method,
`FIGS. 2A and 2B show basic circuit diagrams to
`explain the arc discharge vaporization and cathode
`sputtering processes,
`FIG. 3 is a schematic illustration of an apparatus for
`carrying out the method of the invention,
`FIG. 4 is a schematic representation of a magnetron
`cathode,
`FIG. 5 is a cross-sectional representation of a multi-
`cathode system,
`FIG. 6 is a schematic cross-sectional representation
`of an imbalanced magnetron,
`FIGS. 7 and 8 show an example of a layer build-up
`and of the associated process steps in a schematic illus-
`tration, and
`FIGS. 9 and 10 depict a schematic representation of a
`preferred’ layer sequence and the temporal course or
`time sequence of the associated process steps.
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`The diagram of FIG. 1 shows the typical distribution
`of the kinetic energies of the particles which are inci-
`dent on a substrate to be coated by means of a custom-
`ary arc discharge vaporization method. The kinetic
`energy is plotted along the abscissa and the frequency of
`incidence of the condensing particles is plotted along
`the ordinate.
`
`As can be seen from this diagram, the ideal energy
`range lies, in accordance with experience, at around 40
`to 80 eV. Smaller or larger energies lead to defect
`mechanisms which are set forth in the diagram.
`Basic circuit diagrams for arc discharge vaporization
`and for cathode sputtering are shown in FIGS. 2A and
`2B, respectively.
`In either case a cathode 2 is arranged in a vacuum
`chamber 1. In the case of arc discharge vaporization the
`cathode is held at a potential of -20 V to -50 V. The
`are current forms between the cathode 2 and the anode
`3.
`
`The anode 3 is at a typical potential in the region
`between 0 and +50 V. The are current can amount to
`several hundreds of amperes. A part of the current
`propagates in the space in the direction towards the
`substrates 4. The substrates are maintained, as required,
`at a negative bias of up to 2000 V in the case of an
`etching process and, for example, between 1100 and
`1200 V in the case of forming the transition layer, or at
`ca. 100 V during coating.
`The substrates 4 are fixedly connected to the sub-
`strate holder 5. The latter is positioned inside the cham-
`
`

`
`5,306,407
`
`6
`
`tering source. Finally, FIG. 6 shows the shape most
`frequently represented in the relevant literature for a
`magnetron in cross-section. In this arrangement the coil
`17 again serves to increase the ionization of the space
`and acts in conjunction with the magnet arrangement
`consisting of permanent magnets, preferably of SmCo
`or NdFeB, as an imbalanced magnetron.
`FIGS. 7 and 8 schematically show the various coat-
`ing layers and the individual process steps.
`FIG. 7 shows a typical substrate of steel, the surface
`of which is characterized by the transition layer which
`quasi operates as an “anchoring zone”. When using Ti
`as a coating material, intermetallic phases arise in this
`region, consisting, for example, of TiFe. A first layer of
`TiN then lies on this transition zone and is formed
`through reactive vapor deposition by means of are dis-
`charge vaporization. This layer is then followed by a
`second TiN layer deposited by cathode sputtering.
`FIG. 8 shows the time sequence of the characteristic
`electrical method parameters in a schematic representa-
`tion.
`
`5
`ber l in electrically insulated manner and can be con-
`nected with a suitable power supply.
`_
`In the case of conventional cathode sputtering, the
`negative bias on the cathode is in the range from 3000 to
`4000 V. Typical values for magnetron sputtering lie
`between 400 and 700 V. The space filling plasma of the
`conventional cathode sputtering process is schemati-
`cally indicated with the reference numeral 6. The same
`conditions apply to the substrates 4 and the substrate
`holder 5 as in the case of are discharge vaporization.
`FIG. 3 shows a block diagram of an example of an
`apparatus for carrying out the method of the invention.
`In this arrangement, a common cathode 2 is provided
`for the arc discharge vaporization and the cathode sput-
`tering.
`The cathode 2 is surrounded by a dark field screen 7
`held at ground potential or at a floating potential, or
`insulative material. Cathode 2 and anode 3 are con-
`nected together in the circuit 8. The power supply 9 for
`maintaining the arc discharge and the switch 10 for
`selectively actuating the arc discharge vaporization are
`in power circuit 8.
`Parallel to the power circuit 8 is the power circuit 11
`which connects the power supply 12 to the cathode 2
`via the switch 13 for selective maintenance of the cath-
`ode sputtering discharge. The positive output of the
`power supply 12 is, in known manner, at ground poten- ’
`tial. Finally, a circuit 14 connects the substrate holder 5
`with the negative output of power supply 16 via a
`switch 15. The positive output in this case is either held
`at ground potential or at the potential of the chamber.
`Two possible embodiments of magnetization devices
`for the plasma (reference numeral 6 in FIG. 2) are indi-
`cated by the reference numerals l7 and 18. Depending
`on the particular apparatus, these magnetization devices
`17 and 18 consisting of scattering field coils are electri-
`cally connected with DC power supplies 19 and 20,
`respectively. The level of the coil current is selected
`such that the ion current density at the substrates 4 is
`above 2 mA/cm? under the action of the negative bias
`originating from the power supply 16.
`FIG. 4 shows a known embodiment of a magnetron
`cathode. Reference numeral 2 designates the target of a
`conventional or magnetron cathode. Reference numeral
`21 designates a special magnet arrangement. A scatter-
`ing field coil 17 such as shown in FIG. 3 surrounds the
`arrangement in the region of the target 2. The double
`arrow indicates that the magnetic field is displaceable
`relative to the target 2. This is of practical significance
`because it is of advantage to selectively allow the arc
`discharge vaporization to proceed on its own with or
`without the influence of the magnetic field, whereas
`during cathode sputtering the magnetic field is of im-
`portance for the magnetron operation of the cathode.
`FIG. 5 shows a cross-section of a multi-cathode sys-
`tem. Here two conventional cathodes and the magne-
`tron cathode are located in the chamber 1. One of the
`conventional cathodes can in this case be used as an arc
`discharge vaporizer, whereas the other serves as a sput-
`TABLE
`PIOCCSS parameters
`Unit
`Operational range
`V
`15-50
`A
`40—400
`l0'5 mbar
`0.l—2
`V
`1300-2000
`min
`1-10
`V
`15-50
`
`During the etching process, the bias potential applied
`to the substrate is at its highest value (typically -1600
`V) and is reduced stepwise to form the transition zone
`(typically -1100 V) and during coating with the aid of
`the power supply 16. The current at the substrates is
`initially very high and is reduced during the formation
`of the transition layer.
`During the coating by means of arc discharge vapori-
`zation, and also during the phase of cathode sputtering,
`the negative substrate bias can be held at a constant
`level, i.e. typically 50 V:2S V.
`To achieve an adequate ion current at the substrate
`the arc current (power supply 9) is increased.
`The cathode potential is held almost constant (typi-
`cally -20 V) during the first process steps by means of
`the power supply 9 and is increased by means of the
`power supply 12 to typically -500 _V during the coat-
`ing by cathode sputtering, for example when using
`magnetron cathodes.
`The cathode current during cathode sputtering is
`current controlled by means of power supply 12 and
`remains constant during the course of the further coat-
`ing process.
`The ion current to the substrates (bias current) is
`correspondingly high through the use of additional
`magnetic ionization (for example, by means of the mag-
`netizing devices 17, 18) and is greater than 2 mA/cm3.
`FIGS. 9 and 10 represent a preferred method with
`reference to the example of TiN coating.
`FIG. 9 shows the layer sequence. The TiN-layer lies
`directly above the “anchoring zone”.
`FIG. 10 shows the time sequence of the process steps.
`In comparison to FIG. 8, the phase of arc discharge
`vaporization for the production of a first TiN-layer is
`missing.
`the
`important process parameters for
`The most
`method of the invention are set forth in the following
`table:
`
`l0
`
`I5
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`Process step
`Etching
`
`Process parameter
`Arc potential
`Arc current
`Pressure
`Neg. substrate bias
`Etching time
`Transition zone Arc potential
`
`Preferred range
`20-40
`50-250
`0 5-1
`l500—l600
`2-5
`20-40
`
`

`
`5,306,407
`
`7 T
`
`Process step
`(Ion implant»
`ation)
`
`Coating
`(imbalanced
`magnetron)
`
`ABLE-continued
`PFOCESS parameters
`Preferred range
`Unit
`Operational range
`Process parameter
`50-250
`A
`40-400
`Arc current
`0.5-1
`1O“5 mbar
`0.1-2
`Pressure
`1000-1200
`V
`10()0—1500
`Neg. substrate bias
`5-10
`min
`1-20
`Implantation time
`500-600
`Discharge potential V
`300-750
`10-15
`Discharge power
`W/cmz
`5-30
`1-3
`Total pressure
`10-3 mbar
`0.5—50
`50 i 25
`Neg. substrate bias
`V
`0-500
`2-4
`Bias current density mA/cmz
`1-10
`1-1.5
`Rate
`nm/sec
`0.5—l0
`3-5
`Layer thickness
`pm
`1-10
`Substrate
`“C.
`250-600
`350-450
`temperature
`
`
`20
`
`the arc discharge vaporization, and following it by
`cathodic sputtering until the desired layer thickness is
`reached.
`
`including
`7. Method in accordance with claim 6,
`limiting the layer component thickness produced by are
`discharge to up to approximately 20% of the total layer
`thickness.
`
`8. A method according to claim 6 wherein the layer
`comprises a TiN layer.
`9. Method in accordance with claim 1, wherein im-
`mediately following the formation of the anchoring
`zone a coating is directly effected by means of cathode.
`.10.__Method in accordance with claim 1, including
`producing a boundary bonding layer by directing an
`electric field onto the substrate, slowly and continu-
`ously weakening the electric field by reducing a corre-
`sponding electric bias potential; and, after extinguishing
`the arc, continuously increasing the cathode sputtering.
`11. Method in accordance with claim 1, including
`using the same cathode for the arc discharge vaporiza-
`tion process and for the cathode sputtering process.
`12. Method in accordance with claim 1, including
`using separate cathodes for the arc discharge vaporiza-
`tion process and the cathode sputtering process, respec-
`tively.
`13. Method in accordance with claim 1, including
`operating the sputtering cathode as an imbalanced mag-
`netron.
`
`14. Method in accordance with claim 13, wherein the
`imbalanced magnetron includes a concentric external
`magnetic coil.
`15. Method in accordance with claim 1, including
`controlling the energy of the ions impinging onto the
`substrate during coating by choosing a negative bias
`potential on the substrate in the range of 50:25 V.
`16. Method in accordance with claim 15, including
`setting the bias current density flowing to said substrate
`at a value larger than 2 mA/cm? with the aid of the arc
`current density and the bias voltage during coating by
`means of arc discharge, and with the aid of a magnetic
`coil associated with the cathode during cathode sputter-
`mg.
`
`17. Method in accordance with claim 1, including
`continuously transforming the arc discharge vaporiza-
`tion process into the cathode sputtering process in such
`a way that deposits from the two processes become
`superimposed during the transition.
`18. Method in accordance with claim 1, including
`depositing a mixed layer following the formation of said
`anchoring layer,
`the mixed layer being formed by
`
`LITERATURE:
`
`1. L. Maissel, “Handbook of Thin Film Technology”
`McGraw-Hill Book Company, 1970, p. 4.8
`2. T. Hata, R. Noda, O. Morimoto, T. Hada Appl. Phys.
`Lett.. 37 (3) 1980, p. 633
`3. B. Window, F. Sharples, N. Savvides Vac. Sci.
`Tec}moI., A 3 (6) 1985, p. 2368
`4. B. Window, N. Savvides Vac. Sci. Technol., A 4 (2)
`1986, p. 196
`5. B. Window, N. Savvides Vac. Sci. Technol., A 4 (3)
`1985, p. 453
`6. S. Kadlec, V. Musil, W.-D. Manz, G. I-Iakanssot E.
`Sundgren, 16th ICMC, San Diego, ’U.S.A., 1989
`7. H. Freller, H. P. Lorenz Vac. Sci. TechnoI., A 4 (1986),
`p. 2691
`8. H. Freller Proc. SURTEC, Berlin ’89, Carl Hanser
`Verlag, Munich, 133
`'
`We claim:
`
`25
`
`3'0
`
`35
`
`1. A method for the coating of a substrate in which a
`layer to be applied is produced by condensing particles
`of a plasma generated by means of a gas discharge
`which are incident on the substrate, the method com-
`prising an arc discharge vaporization coating process
`'
`and a cathode sputtering coating process, the are dis- 40
`charge vaporization coating process being carried out
`before the cathode sputtering coating process; the arc
`discharge vaporization coating process being carried
`out with an ion energy and ion flux density which is
`selected to produce an anchorizing zone in the substrate 45
`for the layer by bombarding the substrate with appro-
`priately optimized ion energy and ion current density in
`such a way that ion implantation takes place in which
`ions penetrate into the substrate to a depth of a plurality
`of crystal lattice planes to thereby form the anchoring 50
`zone.
`
`2. Method in accordance with claim 1 including ini-
`tially directing during arc discharge vaporization ions
`of sufficiently high energy and ion current density
`against a surface of the substrate such that the substrate 55
`surface is cleaned and partially removed by ion etching.
`3. Method in accordance with claim 2 wherein the
`step of initially directing takes place by means of ions of
`an inert gas or metal ions originating from the cathode
`or from a mixture of the same.
`4. Method in accordance with claim 1 wherein the
`step of bombarding the substrate takes place with metal
`ions.
`
`60
`
`5. Method in accordance with claim 1 including using
`titanium ions to form the anchoring zone.
`including
`6. Method in accordance with claim 1,
`selecting the parameters during arc discharge vaporiza-
`tion to lead to the deposition of the layer, terminating
`
`65
`
`

`
`5,306,407
`
`10.
`
`15
`
`20
`
`25
`
`10
`trate the substrate with the ions sufficiently to form an
`anchoring zone comprising mixed crystals to a depth of
`200 to 400A beneath the substrate surface.
`27. A method for the coating of a substrate in which
`a layer to be applied is produced by condensing parti-
`cles of a plasma generated by means of a gas discharge
`which are incident on the substrate, the method com-
`prising: an arc discharge vaporization coating process
`and a cathode sputtering coating process, the are dis-
`charge vaporization coating process being carried out
`before the cathode sputtering coating process; and pro-
`ducing a boundary bonding layer by directing an elec-
`tric field onto the substrate, slowly and continuously
`weakening the electric field by reducing a correspond-
`ing electric bias potential, and, after terminating the arc
`discharge vaporization coating process, continuously
`increasing the cathode sputtering coating process.
`28. Apparatus for applying and intimately attaching a
`material
`layer to a substrate comprising: a vacuum
`chamber adapted to be filled with a processing gas; a
`substrate holder electrically insulated from and dis-
`posed within the chamber; a cathode electrically insu-
`lated from and disposed inside the chamber, the cathode
`being provided with material for the layer; an anode; an
`arc discharge first power supply; a cathode sputtering
`second power supply; a first electric circuit operatively
`coupled the cathode,
`the anode and the first power
`supply; a second electric circuit operatively coupling
`the cathode, the substrate holder and the second power
`supply; means for selectively and sequentially opening
`and closing the electric circuits in such a way than an
`arc discharge vaporization coating process is carried
`out first and is followed by a cathode sputtering coating
`process to form said layer on the substrate; and means
`for generating an ion flow having an energy and current
`density during an initial phase of the arc discharge va-
`porization coating process to penetrate ions into the
`substrate to a depth of a plurality of crystal
`lattice
`planes to form an anchoring zone for an enhanced at-
`tachment for said material layer to the substrate.
`10!
`it
`t
`it
`t
`
`9
`means of simultaneous arc vaporization and cathode
`sputtering.
`19. A method for applying a material layer to a sur-
`face of a substrate ‘in a processing gas environment, the
`method comprising the steps of initially bombarding the
`surface of the substrate with ions of an energy and cur-
`rent density selected to implant the ions in the substrate
`to a depth of a plurality of crystal lattice planes, thereby
`forming an anchoring zone for the material layer; there-
`after applying a first portion of the material layer over
`the anchoring zone with an ‘arc discharge vaporization
`coating process; and thereafter forming a second por-
`tion of the material layer over the first portion with a
`cathode sputtering coating process.
`20. A method according to claim 19 wherein the step
`of bombarding forms an initial phase of the are dis-
`charge vaporization coating process.
`‘
`21. A method according to claim 20 including the
`step of etching the substrate surface prior to the'bom-
`barding step, the etching step comprising the step of
`subjecting the substrate to a negative bias of between
`1500 V to 2000 V during a beginning phase of the arc .
`discharge vaporization coating process.
`,
`22. A method according to claim 19 including the
`step of subjecting the substrate to a bias potential of
`between l000 V and 1500 V during the bombarding
`step.
`23. A method according to claim 22 including the
`step of maintaining the substrate at a bias potential of
`between 1100 and 1200 V during the bombarding step.
`24. A method according to claim 19 wherein the step
`of bombarding includes the step of bombarding the
`substrate surface with ions selected from the group of
`materials consisting of Ti, Zr, Hf, Cr, Ta, Nb, and V.
`25. A method according to claim 19 wherein the step
`of bombarding comprises the step of bombarding the
`substrate surface with Ti ions.
`
`30
`
`35
`
`26. A method according to claim 19 wherein the step
`of bombarding comprises the step of bombarding the
`substrate surface with ions of sufficient energy and
`current density and for sufficient length of time to pene-
`
`40
`
`45
`
`50
`
`55
`
`65