CA1238295A - Method of coating ceramics and quartz crucibles with material electrically transformed into a vapor phase - Google Patents
Method of coating ceramics and quartz crucibles with material electrically transformed into a vapor phaseInfo
- Publication number
- CA1238295A CA1238295A CA000476016A CA476016A CA1238295A CA 1238295 A CA1238295 A CA 1238295A CA 000476016 A CA000476016 A CA 000476016A CA 476016 A CA476016 A CA 476016A CA 1238295 A CA1238295 A CA 1238295A
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/4505—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements characterised by the method of application
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
- C23C14/32—Vacuum evaporation by explosion; by evaporation and subsequent ionisation of the vapours, e.g. ion-plating
- C23C14/325—Electric arc evaporation
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
- C23C4/126—Detonation spraying
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
- H05K1/0306—Inorganic insulating substrates, e.g. ceramic, glass
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Structural Engineering (AREA)
- Plasma & Fusion (AREA)
- Physics & Mathematics (AREA)
- Physical Vapour Deposition (AREA)
- Laminated Bodies (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Quartz crucibles for the melting of silicon and ceramic substrates are coated with protective materials or metals at least in part evaporated from an electrode with which an arc is struck at low voltage and current to deposit material from the electrode on the substrate in a vacuum chamber. The electrode may be heated and the substrate may be sandblasted and preheated.
Quartz crucibles for the melting of silicon and ceramic substrates are coated with protective materials or metals at least in part evaporated from an electrode with which an arc is struck at low voltage and current to deposit material from the electrode on the substrate in a vacuum chamber. The electrode may be heated and the substrate may be sandblasted and preheated.
Description
SPECIFICATION
Field of the Invention The invention relates to a method of coating of a substrate with a material which is brought into the vapor phase by electrical jeans.
undo of the Invention , The deposition of material from a vapor phase onto a substrate is well known in the coating art and in the field of surface transformation of a substrate. Generally speaking, a body of the material to be transferred to the substrate is heated in the region of this substrate and transformed first into a molten state and then into a vapor state. The material thus undergoes two phase transformations, namely, the transform matron from the solid phase to the liquid phase and then from the liquid phase to the vapor phase.
The orating is generally effected in a vacuum and usually a relatively high vacuum must be drawn to permit trays-for of vapors from the source to the substrate.
, .
Earlier systems may use induction heating to effect I; 20 the aforementioned phase transformation.
A particular problem has been encountered with respect to the quartz~crucibles~utilized in the production of silicon wafers for semiconductor purposes. Such crucibles in which the elemental Solon lo melted, generally are composed of quartz and are received in a supporting carbon jacket within an induct lion toll which lo utillzed~to melt the elemental silicon. A
monocrystaIline silicon seed can then be lowered into the silicon :, :
-1 - Jo ., ,. . : : ",, " .: . , I
molt of the crucible and raised slowly to draw a silicon bar which is control1edly cooled so that the monocrystalline product can then be cut into wafers. Such crucibles are, for the melt-in of the elemental silicon and during the drawing process brought to and held for many hours at an elevated temperature close to their softening point and at a temperature at which attack by the molten silicon can occur. This causes deterrer-lion of the crucible and threatens the introduction of undesired impurities in the waxers which are produced.
Hence the semiconductor field has long sought a method of protecting such crucibles which will increase their life.
Another problem is the application of metals to core-miss. While many metals can be coated onto ceramics, the refract tory metals such as tungsten and titanium have been applied here-tougher in a manner which is less than satisfactory and practically in all cases adhesion problems are encountered by the methods used heretofore.
: :
Jo An object of this invention is to provide a method or the vapor deposition ox material on large-area and/or complex configuration substrates at relatively low-energy oust and with improved uniformity.
It is also an object of the invention to provide a method for the whopped coating of complex and/or large-area surfaces.
Yet another object of the invention is to provide an improved method ox protecting quartz crucibles of the type Utah-I- lived in the semiconductor yield so asset increase the life thereon.
, .
I
Sill]. another object of this invention it to provide an improved method of applying metal coatings to ceramics whereby the poor adhesion problems characterizing prior art systems are avoided.
summary of the Invention These objects and others which Wylie become apparent hereinafter are attained in accordance with this invention, in a method of vapor deposition which is based upon the discovery that especially large-area surface deposits can be formed by juxtaposing an elongated electrode of the depositing material, laterally with the surface of the substrate to be coated over a substantial portion of the length a the electrode in a vacuum, and striking an arc between one end of this electrode and a counter electrode such that the arc current should be between 50 and 90 amperes with a voltage applied across the electrode of 30 to I volts.
Surprisingly, once the arc is struck as the two elect troves are separated, the arc, a portion of the arc or a heating effect generated by the arc appears to spiral around the long electrode and cause vaporization of the material of the electrode , in a generally helical or spiral pattern progressively moving away from the counter electrode.
It is indeed a remarkable surprise that the arc is not : :
confined to the space between the two electrodes but rather has a component or an effect which spirals away from the counter electrode toward a~;reglon of the length ox the one electrode Jo which is further removed prom the counter electrode in spite, of the foot that the greatest conductivity would appear to lie in a line directly between the two electrodes where the major portion of the arc appears to be confined. This effect is manifest in the fact the long electrode, lye. the deposition electrode, while ; -3-I
originally of uniform cross section, develops a taper toward the counter electrode and coating from the blank of the deposit lion electrode onto the substrate can be observed at consider-able distance from the arc's striking face of the deposition electrode.
In fact, the effect appears to survive for a brief period following extinction of the original arc and hence it is preferred to periodically contact and separate the electrodes to generate the arc and then allow extinction thereof.
According to a feature of the invention, means is provided at an end of the electrode of the material to be depot sited, remote from the arc-striking electrode to control the temperature of the material-supplying electrode, generally to maintain it in the range of 800F to 1000F, the speed under the lower voltage, lower current and temperature conditions of the present invention, at which the material evaporates from the material-supplying electrode, can be increased by 1.5 to
Field of the Invention The invention relates to a method of coating of a substrate with a material which is brought into the vapor phase by electrical jeans.
undo of the Invention , The deposition of material from a vapor phase onto a substrate is well known in the coating art and in the field of surface transformation of a substrate. Generally speaking, a body of the material to be transferred to the substrate is heated in the region of this substrate and transformed first into a molten state and then into a vapor state. The material thus undergoes two phase transformations, namely, the transform matron from the solid phase to the liquid phase and then from the liquid phase to the vapor phase.
The orating is generally effected in a vacuum and usually a relatively high vacuum must be drawn to permit trays-for of vapors from the source to the substrate.
, .
Earlier systems may use induction heating to effect I; 20 the aforementioned phase transformation.
A particular problem has been encountered with respect to the quartz~crucibles~utilized in the production of silicon wafers for semiconductor purposes. Such crucibles in which the elemental Solon lo melted, generally are composed of quartz and are received in a supporting carbon jacket within an induct lion toll which lo utillzed~to melt the elemental silicon. A
monocrystaIline silicon seed can then be lowered into the silicon :, :
-1 - Jo ., ,. . : : ",, " .: . , I
molt of the crucible and raised slowly to draw a silicon bar which is control1edly cooled so that the monocrystalline product can then be cut into wafers. Such crucibles are, for the melt-in of the elemental silicon and during the drawing process brought to and held for many hours at an elevated temperature close to their softening point and at a temperature at which attack by the molten silicon can occur. This causes deterrer-lion of the crucible and threatens the introduction of undesired impurities in the waxers which are produced.
Hence the semiconductor field has long sought a method of protecting such crucibles which will increase their life.
Another problem is the application of metals to core-miss. While many metals can be coated onto ceramics, the refract tory metals such as tungsten and titanium have been applied here-tougher in a manner which is less than satisfactory and practically in all cases adhesion problems are encountered by the methods used heretofore.
: :
Jo An object of this invention is to provide a method or the vapor deposition ox material on large-area and/or complex configuration substrates at relatively low-energy oust and with improved uniformity.
It is also an object of the invention to provide a method for the whopped coating of complex and/or large-area surfaces.
Yet another object of the invention is to provide an improved method ox protecting quartz crucibles of the type Utah-I- lived in the semiconductor yield so asset increase the life thereon.
, .
I
Sill]. another object of this invention it to provide an improved method of applying metal coatings to ceramics whereby the poor adhesion problems characterizing prior art systems are avoided.
summary of the Invention These objects and others which Wylie become apparent hereinafter are attained in accordance with this invention, in a method of vapor deposition which is based upon the discovery that especially large-area surface deposits can be formed by juxtaposing an elongated electrode of the depositing material, laterally with the surface of the substrate to be coated over a substantial portion of the length a the electrode in a vacuum, and striking an arc between one end of this electrode and a counter electrode such that the arc current should be between 50 and 90 amperes with a voltage applied across the electrode of 30 to I volts.
Surprisingly, once the arc is struck as the two elect troves are separated, the arc, a portion of the arc or a heating effect generated by the arc appears to spiral around the long electrode and cause vaporization of the material of the electrode , in a generally helical or spiral pattern progressively moving away from the counter electrode.
It is indeed a remarkable surprise that the arc is not : :
confined to the space between the two electrodes but rather has a component or an effect which spirals away from the counter electrode toward a~;reglon of the length ox the one electrode Jo which is further removed prom the counter electrode in spite, of the foot that the greatest conductivity would appear to lie in a line directly between the two electrodes where the major portion of the arc appears to be confined. This effect is manifest in the fact the long electrode, lye. the deposition electrode, while ; -3-I
originally of uniform cross section, develops a taper toward the counter electrode and coating from the blank of the deposit lion electrode onto the substrate can be observed at consider-able distance from the arc's striking face of the deposition electrode.
In fact, the effect appears to survive for a brief period following extinction of the original arc and hence it is preferred to periodically contact and separate the electrodes to generate the arc and then allow extinction thereof.
According to a feature of the invention, means is provided at an end of the electrode of the material to be depot sited, remote from the arc-striking electrode to control the temperature of the material-supplying electrode, generally to maintain it in the range of 800F to 1000F, the speed under the lower voltage, lower current and temperature conditions of the present invention, at which the material evaporates from the material-supplying electrode, can be increased by 1.5 to
2.0 times the speed of evaporation of the earlier systems.
Practically all metals, alloys, carbides and silicides can be :
used in marine the material-supplying electrode. In addition to metals and other alloys, carbides, brides, silicides and nitrides can be deposited on the substrate.
While it is not fully understood why the rate of ova-portion of the material to be deposited increases with the lower energy utilization of the present invention, it is possible that the migration of the arc may spread the otherwise pooled moltion~phase over a wider area of the material-supplying elect trove to allow, in effect, evaporation of the molten metal in thin film forum Lo cording to another feature of the invention, the principles set forth above are utilized in the application of metal coating to synthetic resins, the synthetic resins in the form of cabinets or housings for electronic components. It's been found, most surprisingly, that since the substrate is unaffected by the large area coatings which can be applies in accordance with the invention, the invention is highly advantageous when utilized to coat the interiors of synthetic resin cabinets or housings which may be utilized for electronic components, the coating forming an electromagnetic shield.
It has also been found, most surprisingly, that the invention is highly effective in applying pure silicon coatings, or other protective coatings, e.g. silicon carbide, silicon nitride or boron nitride, to the interior surfaces of the quartz crucibles hitherto utilized for the melting of silicon in the I; production of the monocrystalline bars to be drawn from the molten silicon in the semiconductor yield. Furthermore, the o invention may reutilized in the application of metal coatings to ceramics, with improved adhesion, even when the applied metals are nickel, tungsten, titanium, tantalum and like refract tory metals which have been difficult to apply heretofore to ceramic substrates. Practically any ceramic substrate may be utilized for the purpose ox the invention and in the case of the quartz crucible sand the ceramic substrates, it is preferred to subject the surfacs~adapted to receive the coating to a sandblasting or other blast-roughening procedure. The term "sandblasting" is here utilized to describe the entrainment of abrasive particulatss against the surface, the abrasive part-curates being generally metal particles, silicon carbide, sift-
Practically all metals, alloys, carbides and silicides can be :
used in marine the material-supplying electrode. In addition to metals and other alloys, carbides, brides, silicides and nitrides can be deposited on the substrate.
While it is not fully understood why the rate of ova-portion of the material to be deposited increases with the lower energy utilization of the present invention, it is possible that the migration of the arc may spread the otherwise pooled moltion~phase over a wider area of the material-supplying elect trove to allow, in effect, evaporation of the molten metal in thin film forum Lo cording to another feature of the invention, the principles set forth above are utilized in the application of metal coating to synthetic resins, the synthetic resins in the form of cabinets or housings for electronic components. It's been found, most surprisingly, that since the substrate is unaffected by the large area coatings which can be applies in accordance with the invention, the invention is highly advantageous when utilized to coat the interiors of synthetic resin cabinets or housings which may be utilized for electronic components, the coating forming an electromagnetic shield.
It has also been found, most surprisingly, that the invention is highly effective in applying pure silicon coatings, or other protective coatings, e.g. silicon carbide, silicon nitride or boron nitride, to the interior surfaces of the quartz crucibles hitherto utilized for the melting of silicon in the I; production of the monocrystalline bars to be drawn from the molten silicon in the semiconductor yield. Furthermore, the o invention may reutilized in the application of metal coatings to ceramics, with improved adhesion, even when the applied metals are nickel, tungsten, titanium, tantalum and like refract tory metals which have been difficult to apply heretofore to ceramic substrates. Practically any ceramic substrate may be utilized for the purpose ox the invention and in the case of the quartz crucible sand the ceramic substrates, it is preferred to subject the surfacs~adapted to receive the coating to a sandblasting or other blast-roughening procedure. The term "sandblasting" is here utilized to describe the entrainment of abrasive particulatss against the surface, the abrasive part-curates being generally metal particles, silicon carbide, sift-
3 con nitride, diamond dust, iron oxide, silicon dioxide or any Jo I
other materiel capable of surface roughening. The entraining gas can be air or any other available gas. In both cases, in addition, the substrate may be preheated within the vacuum chamber or prior to introduction into the vacuum chamber to a temperature less than the melting point of the metal. The preheating temperature should be at least several hundred degrees, however.
Ceramic coating is effected in accordance with the present invention, by juxtaposing two electrodes of different metals, preferably a highly conductive and a highly refractory metal with a substrate which is preferably a ceramic body, and striking an arc between these electrodes in an evacuating chamber containing the electrodes and the substrate. According to the invention, the electrodes are first given a relative polarity, i.e. one is poled positively while the other is poled negatively to deposit the metal from one of these electrodes selectively while at the same time, it appears, depositing a small amount of this latter metal on the second electrode.
When polarity is then reversed, the metal vaporizes preferentially prom the second electrode, initially including the small portion of the metal from the first electrode which is deposited thereon so that at the interface between the two layers a mixed composition of the metals is formed.
The disadvantages, which have hitherto been encountered when high conductlvlty~metals, especially copper but also gold and silver, are applied to a ceramic substrate with respect to : :
; adhesion and especlally~with respect to adhesion after or during soldering or other welding ox conductivity elements thereto, oan~be obviated if, prior to the application of the high conduct 3 ~iVlty metal, the ceramic is coated with a refractory metaling a comparatively small thickness and this intermediate layer of coating is in turn coated with the conductive metal.
More particularly, it has been found that it is possible to deposit a coating of a thickness of, say, 5 to 10 microns of tungsten, molybdenum, titanium or zirconium as the refractory metal upon the substrate and thereafter to apply a coating of greater thickness, say 0.001 to 0.02 inch of copper of a copper alloy, gold, silver or some other non refractory metal, i.e. metal having a substantially lower boiling point than that of the refractory metal which is used.
It has been found that, when a two-electrode method is used, according to the invention, it is possible to keenest-lute one electrode as the refractory metal and the other elect trove as the non refractory metal and by regulating the polarity of the electrodes during the deposition, the particular metal i which is deposited can be controlled.
With the present invention, it has been found that it is possible to increase the adhesion, in terms of the force no-squired to separate the coating from the substrate by 100 or more times, all other things being equal, when the thin refract tory metal Catalina is applied between the copper coating and the ceramic substrate.
A ceramic substrate can be used in accordance with the present invention and masking techniques can be employed to ensure the formation of the deposit in any desired pattern.
According to an important feature of the invention, one of the two electrodes which are juxtaposed with the substrate can be moved out of alignment with the other electrode and no-; placed by a substitute electrode and the process repeated with ' the latter to additionally deposit at least a layer of the meatloaf the third electrode upon the second layer.
Brief Description of the Drawing __ The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompany-in drawing in which:
FIG. 1 is a diagram in elevation Al view illustrating an apparatus for carrying out vapor deposition in accordance with an embodiment of the present invention;
FIG. 2 is a similar view of another apparatus wherein, however, the vapor deposited material is collected on a vertically reciprocal electrode;
FIG. 3 is a vertical section, also in diagrammatic form, illustrating an apparatus for depositing material upon a substrate disposed below the pool of metal;
Jo FIG. 4 is a view similar to FIG. 3 illustrating :
another embodiment of the invention;
FIG. 5 is an axial cross-sectional view of another Jo 20 apparatus for depositing material upon a substrate according to I-; this invention;
FIG. 6 Sian axial cross-sectional view of a highly compact portable apparatus for carrying out the method of the invention FIG. issue a diagrammatic cross sectional view of another apparatus for carrying out the present invention;
: FIG. 8 is a diagrammatic section illustrating the application of the invention to the coating of a quartz crucible or use in the production of semiconductor wafers;
Jo : :
I: :
US
FIG. 9 is a view of still another device diagram-tidally illustrating the application of large area coatings to ceramic substrates according to the invention;
FIG. 10 is a diagram of an apparatus for carrying out the ceramic-coating method of the present invention;
FIG. 11 is a cross-sectional view drawn to a larger scale of a product of the present invention;
FIG. 12 is a view similar to FIG. 10 but illustrating another apparatus for carrying out the invention;
FIG. 13 is a diagram showing an effect obtained during the deposit of the metal for the first layer before the commencement of the second layer; and FIX. 14 is a cross-sectional view through the product in the latter case.
,:
Specific Description In FIG. 1 there is shown a system utilizing a simple !
arc method in accordance with the present invention for obtaining mirror-like protective coaxings upon substrates or for evaporate ing~various metals or metal alloys, including heat-resistant ; 20 and refractory metals, to apply coatings thereof to the substrate.
As is apparent from FIG. 1, the basic apparatus can include a vacuum chamber, not shown, which can be similar to :
the vacuum chamber of FIG. 6 and in which a metal electrode 1 own be fed by an electrode feeder 7 toward an electrode body 2 to form the pool 3 of molten metal with which the arc is struck. ;
; The electrons body 2 is held in a fixture or holder 5 and the direct-current source applies the arc current across the electrode 1 and the body 2 via a conventional art stabilizing circuit represented at 8.
I US
It has been found to be advantageous to provide the relatively small cross-section electrode 1 with a thermal regular ion 6 tending to prevent, overheating of this electrode Since the cross section of body 2 is substantially larger than that of the electrode 1, the pool 3 lies in a concave recess formed in situ in the body 2.
Jo The apparatus of FIG. 1, utilizing electrodes Lund 2 of titanium, aluminum, tungsten, tantalum or copper, strikes an arc at a temperature of 5000 to 7000F to generate vapor of the metal of the pool 3 which traverses the distance of 10 to 15 cm to the substrate 10 and forms a coating of the metal thereon.
.
The pool 3 can be formed by a mixture of metal contributed by the electrodes 1 and 2, thereby depositing an alloy of the metals ; of the two electrodes upon the substrate. Preferably the elect strode lo composed of titanium while the molten metal predominantly consists of aluminum, tungsten, tantalum or copper.
The apparatus of FIG. 1, without substantial midlife-cation, can be utilized in a non crucible method of generating protective coatings of carbides, for producing solaced coatings on the substrate or for forming carbide or solaced and even silicon carbide layers upon the substrate. To deposit silicon carbide-tungsten carbide layers on the substrate, electrode 2 is composed ox graphite and electrode 1 of tungsten solaced, The vacuum is initially drawn to 10 6 torn and maintained at 10 5 torn or lower Roy direct current arc-generating voltage ; is 100 volts and the arc current 150 amperes. The deposit forms at a rate of about 0~2 grams per minute.
:
s In this case, the apparatus of FIX. 1 is used, again in the usual]. vacuum chamber, although the electrode 1 can be composed of silicon or carbon while the electrode 2 is composed of a metal whose solaced or carbide is to be formed or, in the case of a deposit of silicon upon the sub-striate, can also consist of silicon.
For example, when a silicon carbide deposit upon the substrate 10 is desired, the electrode 1 may consist of silicon while the electrode 2 is a carbon block in which a pool 3 of silicon and solubilized carbon is received.
The vapors are transferred to the substrate and Jo deposited in a silicon carbide layer thereon. The substrate may be titanium and the deposit formed on the substrate may be a mixture of titanium solaced and titanium carbide.
Alternatively, when the electrode 1 is composed of silicon or carbon, and the electrode body 2 is composed of titanium, titanium carbide or solaced can be deposited on a substrate of a different composition.
When a slight oxidizing atmosphere is provided in the evacuated chamber, silicon dioxide deposits are formed on the substrate.
Obviously the apparatus of FIG. 1 is particularly effective in the production of semiconductors.
The th~ermoregulator 6 may be duplicated along the length of the electrode 1 and additional thermoregulators may . .
be provided for the electrode body 2 to prevent overheating , :
thereof.
When either the electrode 1 or the body 2 is come , :
posed of silicon and the other is composed ox carbon, silicon !
carbide is generated by the reaction and deposits in a higher purity than that of the original silica and carbon.
Jo :
' , - , , OX
When both of the electrodes are composed of silicon, high density silica and silicon deposits can be obtained as is particularly desirable for the coating of semiconductors.
The apparatus of FIG. 2 is generally similar to that of FIG. 1 but operates under somewhat different principles, the evaporation being effected at least in part from the wetted upper electrode 101.
In this Figure, elements which correspond to those of FIG. 1 utilize similar reference numerals differing in the hundreds position.
In FIG. 2, the electrode feeder 107 is coupled with a vertical reciprocator 112 which imparts a reciprocation to the electrode 101 in the direction of the arrow 114 so as to periodic gaily plunge the tip of the electrode 101 into the pool 103 of the molten metal formed in the electrode body 102.
Upon rising from this pool to restrike the arc I04, the coating 113 of molten metal upon the electrode lulls evapora-ted and the deposit is formed upon the substrate 110.
The electrode body 102 is shown in the holder I05 and the arc current supply is formed by the direct current source I, 109 and the stabilizer 108 in the manner described, the electrode 101 being provided with the thermoregulator 106.
This system has been found to be particularly effect live, in a modification of the foregoing example, when the electrode 101 is composed of titanium and the pool 103 is formed of aluminum.
In FIG. 3 there is shown an embodiment of the invent lion in which the vapor is deposited upon a substrate 210 disk posed below a crucible 217 in the form of an upwardly open 3 ring containing the molten metal 203, the crucible being mounted -I in a holder or frame 205.
I
Here the upper electrode 201 is in the form of a spheric eel segment which functions as a reflector so that, when an arc 204 is struck between the electrode 201 and the melt in the crucible 217, the vapors pass upwardly as represented by the arrows 219 and are reflected downwardly to focus upon the sub-striate 210 as represented by the arrows 218.
The direct current source 209 is here connected across the electrode 201 and the crucible 217 via the arc stabilizer 208 and the upper electrode 201, mounted on the rod 216, is Yen-tidally positioned by the feeder 207 and horizontally positioned by an auxiliary mechanism 215 which adjusts the position of the electrode 201 over the evaporating metal.
In this embodiment, the electrode Sol can be composed of titanium, molybdenum or tungsten while the molten metal can be composed of aluminum or copper and the crucible 217 of gray White.
In FIG. 4 there is shown another embodiment of the invent lion in which the vapors flow downwardly to deposit upon the substrate 310.
Z In this oases the upwardly open crucible 317 containing the molten metal 303 can be supplied with additional molten metal from a ladle or other sources represented at 322 or with solid metal which is melted in the crucible 317. The latter can be Jo heated by auxiliary means such as an inductive heater 323 and is supported in a holder 305.
Jo : The bottom of the crucible 317 is formed with apertures 321 at which droplets of the molten metal appear, these droplets being vaporized by the arc 304 struck between the electrode 301 ~'~ and the bottom of the crucible 317.
The temperature in the region of the arc can be con-trolled by an auxiliary inductive means 324 and the electrode 301 can be cooled as represented by the cooling element 306.
Electrode 301 is fed toward the crucible 317 by the electrode holder 307 and the arc is maintained by an arc stab-liver 308 connected to the direct current source 309.
In this embodiment, the molten metal may be copper.
In place of the auxiliary device 324, a substrate to be coated may be provided at this location, e.g. in the form of a titanium ring, which can collect the vapor in the form of a coat-in.
The embodiment of FIG. 5 evaporates the molten metal as , it is formed in a closed space, the vapors being discharged through apertures 425 on the substrate 410.
In this case, the pool of liquid is formed by melting ;
the electrode 402 supported by the holder 405 by feeding the I, counter electrode 401 via the electrode feeder 407 through a central bore 426 in the electrode 402, the electrode 401 passing through an insulating sleeve 427 forming a guide. A temperature regulator 406 lo provided coccal around the two electrodes adjacent the arc 404 to prevent overheating in the region ahead of the apertures 425. The deposit is formed on the substrate 410.
The current is supplied between the electrodes through I; the arc stabilizer 408 and the direct current source 409 in the manner described previously.
FIG. 6 shows a portable voltaic arc device for~depositlng 'I; reflective anticorrosive, protective and semiconductor type metal, silicide~and carbide coatings using the principles dyes cried previously.
This apparatus comprises a vacuum chamber 500 which is :
formed at its upper end with a handle 530 enabling the portable unit to be readily transported.
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I
Within this chamber, there is provided a hollow sphere 517, the lower part of which forms a crucible for the molten metal 503, coated internally with a high-temperature heat nests-lent (refractory) material such as aluminum oxide.
The upper portion of this sphere is coated at 531 with a reflective layer concentrating the heat reflected from the bath back onto the latter.
An arc 504 is struck between an electrode 501 and the bath 503, the electrode being fed by the unit 507 toward the bath as the electrode material is consumed.
Additional metal, e.g. in solid form, is fed to the bath as a rod 532 which also is connected to the feeder 533 ' so that as the bath is consumed, additional metal is supplied thereto.
The electrode 501 and the bath 503 are connected to opposite terminals of an arc stabilizer and a direct current source in the manner previously described.
A tubular electrode 502 surrounds the rod 532.
The lower part of the chamber 500 is provided with an air pump as represented at 533, the latter evacuating the chamber - 20 containing the hollow sphere 517 and, via a vacuum hose 534, via a valve 535, an adapter 536 of outwardly divergent configure-lion which can be connected to a lateral aperture 525 of the hollow sphere 517.
` The adapter 536 can be formed with a heating coil 537 to prevent undesired condensation of vapor thereon.
. .
Between the aperture 525 and the adapter 536 there is provided a vacuum lock 538 and a mounting arrangement 539 for holding a variety of adapters of different shapes and sizes.
The adapter 536 is also formed with a vacuum gasket 5~0 3 whereby the adapter can bear against the substrate 510 to be coated.
;
s The portable unit shown in FIG. 6 is carried to the location of the substrate 510 to be coated and the appropriate adapter 536 is mounted on the fitting 539 and the gasket 540 pressed against the surface 510 to be coated. The arc current is supplied and the system is evacuated by the air pump 533, thereby melting the metal and forming the bath 503 within the hollow sphere. The gate 538 is then opened and the vapors per-milted to pass onto the substrate 510 at least in part by pressure differential as controlled by the valve 535 maintained between the interior ox the sphere 517 and the adapter 536.
Practically any product at any site can be coated and the use of a variety of adapters of different shapes and sizes enables coating of even intricate bodies without moving them from the area in which they are to be used. The device can be collapsible so as to be used to provide coatings inside ducts and the like.
The apparatus shown in the drawing, without the adapter 536, can be used as a propellant for individuals or equipment in space.
20~ Upon generation of the arc, one need only open the gate 53~ to discharge a stream through the aperture 525 and effect propulsion in the opposite direction. The vacuum in spate provides a natural vacuum for the device and no air pump 533 is then required Practically any waste found in space applications can be utilized in the vessel 517 to generate such propulsion.
In FIG. 'Thor is shown an embodiment of the invention , which combines features previously described and concepts developed above.
In this system, which can be used to deposit a coating 3 610' on the inter surface aye of a tube 610, forming a sub-striate, of complex shape, a material-supplying electrode 602 of corresponding shape is mounted centrally of the tube on a support I S
aye and is provided with an induction heating coil aye of a temperature controller 606 which can have a thermocouple 606b or a like temperature sensor responsive to the temperature of the material-supplying electrode 602 for maintaining the tempera-lure of the latter constant in the range of 800 to 1000F by conventional feed-back control circuitry.
As in the previous embodiment, the substrate and the source of the material to be deposited on the substrate are en-closed in a vacuum chamber 600 which can be evacuated to 10 6 torn so that vapor deposition can be effected at a pressure of 10-5 torn.
The end of the material-supplying electrode 602 is provided with an arc-striking electrode 601 which can be respire-acted toward and away from the electrode 602 by an electrically controlled reciprocating drive 607~ The latter can be operated in response to a zero current detector aye so that when the arc current decays completely, the electrode 601 is displaced to the Jo left into contact with the end aye of the electrode 602 and is then withdrawn to reestablish an arc. The arc current is pro-voided by a pulsating direct current source 609 across which an arc stabilizer 608 the parameters of the arc current and arc :~:
voltage are adjusted within the range of 50 to 90 amperes and 30 to 60 volts by these circuit elements.
In practice, utilizing the system illustrated once the arc is struck, the arc itself, an evaporation effect or some other electromagnetic phenomenon appears to progress as represented by the arrow A generally helical and spiral where ~,~ arc-striking location and vapor deposition takes place over the entire length of the ~aterial-supply electrode 602 which is sub-jetted to this phenomenon, i.e. over the length at which the phenomenon is effective until the arc decays.
I' :
The material loss from the electrode 602 gradually transforms it into a tapered shape as represented by the dot--dash lines as 602b in FIG. 7.
The fact that the taper results in a recession of the electrode from the substrate does not create any problem of significance because the greatest deposit is at the region of greatest recession and consequently, the ultimate coating as it progresses along the substrate is highly uniform.
The system of the invention is especially useful in coating temperature-sensitive materials with very small thick-messes of coating material since the coating is especially rapid and it is possible to carry out the deposition without significantly heating up the substrate.
A copper electrode 602 of the shape shown is prove-Dodd Inca substrate tube with an initial spacing of electrode 602 from the substrate of about 10 cm. The electrode is main-twined at a temperature of 900F and an arc is struck in the manner previously described at one end. The arc current is about 70 amperes and the voltage applied after the electrode 601 is withdrawn to form the arc is about 40 volts. The speed of evaporation from electrode 602 under these conditions ox-coeds the speed of evaporation in Example 1.
; In FIG. theorization an arrangement for applying a silicon coating 710' to a quartz crucible 710 of the type utilized for the melting of silicon and from the melt of which a monocrystalline bar of silicon can be drawn for subsequent slicing into silicon wafers and use in the semiconductor in-dusty. According to the invention, the interior surfaces of 3 the crucible are sandblasted and the crucible is preheated, :;; :: :
- ' Lo e.g. to a temperature of 200 to 600C before the crucible is placed in the vacuum chamber. A pair of silicon electrodes 701 and 702 are juxtaposed with one another within the crucible and, utilizing the electrode reciprocating means of the type shown at 607, the electrodes are brought together and then separated as represented by the arrows aye and 707b so they touch and then are drawn apart to stroke the arc. The power supply which can also be of the type described is represented at 709. The arc current can again be 50 to 90 amperes and the arc voltage some 30 to 60 volts. A substantially uniform highly adherent silicon coating can be obtained, especially when the silicon is initially heated, e.g. by means similar to that utilized in the embodiment of FIG. 7.
When a nitrogen atmosphere is released in the region of the arc, the deposit is of the silicon nitride Sweeney. When ' one of the electrodes is composed of carbon, a silicon carbide , deposit is-formed. The same system can be used for coating `'~ any substrate with pure So or one of the other coatings mentioned.
After the initial arc is produced the electrodes can be cooled.
In FIG. there is shown a system for the large area coating of a ceramic substrate 801 which prior to introduction into the vacuum chamber can be initially preheated, after its ; coating-receiving surface has been sandblasted, by the movement of a burner 820 along the underside of the substrate. The elect trove 801 can be composed of a refractory metal or nickel and via the actuator 807 is urged into contact with and withdrawn from contact from the counter electrode 802 which may also be composed of the same metal.
:
The power supply has been represented at 809. The 3 electrodes are here mounted on a track 821 and are moved along the substrate so that as the arc is repeatedly struck and the I
, ~3~9~
arc travels along the electrode 801 in the vacuum chamber receive in the entire assembly, the entire surface of the substrate is coated utilizing the principles described in FIG. 7.
E pie Utilizing an apparatus operating with the principles shown in FIG. 9, an aluminum oxide plate is coated to a thick-news of` l to 2 miss with tungsten utilizing tungsten electrodes.
The arc current is 50 amperes and the arc voltage 40 volts for a maximum electrode spacing of' approximately 4 mm. The electrode diameter was about l cm. The tungsten coating was highly ad-hornet to the alumina plate.
FIG. 10 shows an apparatus, in a highly diagrammatic form, for carrying out the method of the invention. This Papa-fetus comprises a chamber 1010 which can be evacuated by a suction pump 1011 to the desired degree of` vacuum, generally lo 5 to 10 6 torn. Within this chamber, by means not shown, a ceramic substrate 1012 can be disposed and can be shielded by a mask diagr~ammatica]ly~illustrated at 1013 so that coating can only occur in regions defined by the windows 1014 in the mask. 'I
Within the vacuum chamber the portion of the substrate to be coated is juxtaposed with a pair ox electrodes, i.e. a copper electrode 1015 and a tungsten electrode 1016, the elect triodes being provided with means such as the electromagnetic motors (solenoids) 1017 and 1018 for briefly bringing them into contact to strike the arc and then drawing them apart. The purser or periodically energizing the devices 1017 and 1018 have been shown at loll.
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The power supply comprises the alternating current source 1020 which is connected to a rectifier 1021 and the latter is provided with a reversing switch 1022 which can no-verse the polarity of the electrodes 1015 and 1016 under the control of a timer 1023.
In operation with the copper electrode 1015 poled positively and the tungsten 16 poled negatively an arc can be struck by passing an electric current of 30 to log amperes at a voltage of 40 to 100 volts through and across the gap after the electrodes briefly touch to preferentially vaporize tungsten and thus deposit tungsten through the window 1014 of the mask 1013 on the substrate. The duration of coating is controlled by the timer 1023 which, after the coating of the order of microns in thickness has been applied, reverses the polarity so that the copper electrode 1015 is now poled negatively and the tungsten electrode 1016 is poled positively whereupon copper is vaporized from the electrode 1015 and deposited upon the substrate.
As can be seen from FIG. 11, the resulting article has a substrate 1030, ego us aluminum oxide, bearing a copper coat-in 1032 which is separated by the refractory metal coating 1031 (tungsten) of smaller thickness.
Example Utilizing the principles described, a current of about , 70 amperes, a voltage of 80 volts and a vacuum of about 10 5 torn, an aluminum ogle plate is coated with tungsten to a thick- ;
news of about 8 microns and with copper to a thickness of about 0.002 inches. The adhesion is measured and for the coating is found to be 500 to 700 lobs per square inch (force required to remove the coating). When under identical conditions a copper I
coating of the same thickness is applied to the same substrate, the adhesion is only 6 to 8 lobs per square inch. The direct copper-to-ceramic bond is found to be sensitive to both mechanic eel and thermal effects when a solder connection is made to it and with the copper/tungsten contact, formed according to the invention, no similar sensitivity was found.
Practically identical results could be obtained by substituting molybdenum, titanium and zirconium for the tungsten and with combinations of these refractory metals with one another and with tungsten as intermediate layers. Similarly, high degrees of' adhesion were obtained with nickel, gold silver and alloys thereof with one another and with copper.
FIG. 12 shows a modification of the apparatus of FIG.
10 in which the chamber 1110, evacuated by the pump 1111, in-eludes a ceramic substrate 1112 which is to be coated with a plurality of metals. In this case, in addition to the common electrode 1116 and its actuator 1118 driven by the pulserltimer 1119, a pair of counter-electrodes 1115 and aye, respectively of copper and gold, are provided each with a respective actuator 1117, aye. The counter-electrode assembly is provided on a track 11124 having a drive enabling shifting of the two electrodes to the left as illustrated by the showing of the electrode 1115 in its shifted position in dot-dash lines. Naturally in the latter position, the electrode aye is aligned with the common electrode 1116. A reversing switch 1122 as described in connect lion with FIG. 10 19 here also provided and the apparatus is energized from the alternating current lines 1120 through the rectifier 1121.
In this mode of operation, once the chamber is evoke 3 ted, the actuators 1117 and 1118 are operated to move the elect troves 1115 and 1116 together and apart to strike an arc, the -22_ I
electrode 1116 of tungsten being poled positively while the electrode 1115 of copper is poled negatively.
This process is continued in the manner described until the initial coating of tungsten has been brought up to the desired thickness.
As can be seen from FIG. 13, this procedure not only results in erosion of the tungsten electrode 1016 but it also gives rise to a small deposit 1025 of tungsten on the copper electrode 1015.
When the polarity is now reversed 7 i.e. the copper electrode 1015 is poled positively and the tungsten electrode is poled negatively, the arc is struck and evaporation is effect ted from the copper electrode, the tungsten deposit 1025, which has been exaggerated in thickness in FIG. 13, vaporizes together with copper and a mixed tungstentcopper deposit is produced as an interface.
In FIG. 14, for example, the substrate 1112 is shown to have been coated at 1131 with the tungsten layer. The mixed or tungsten layer 1126 is then applied thereto before, with con-Tunisian of the generation of vapor by arc-striking between the electrodes 1115 and 1116, the copper coating 1132 is applied.
When the topper coating has reached the desired thick- ;
news, the electrode assembly 1115, 1117 is shifted to the left I:
and replaced Beth assembly aye, aye and the arc is struck between the electrodes aye, 1116 to deposit gold in a layer ; 1133 upon the topper coating.
A controller 1127 may be provided for the electrode shifting device 1124, the pulser/timer 1119 and the reversing switch 1122 and may be controlled by a preprogrammed MicroPro 3 censor to effect the polarity reversal and the switching of electrodes when layer thicknesses of the desired magnitude have been achieved.
eye The method of Example 4 is practiced except that the copper electrode is shifted away and replaced by a gold elect trove. Utilizing the same vacuum and striking a similar arc, a flash coating in the order of the 5 microns range of gold was deposited upon the copper coating under the condition recited for copper deposition.
The adhesion was not diminished and the resulting gold layer was found to make an ideal contact for micro-elec-ironic purposes. Investigations of the interface between copper and tungsten showed mixed transition zone 1126 which was traced to the vaporization of a minor deposit of tungsten from the copper electrode.
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other materiel capable of surface roughening. The entraining gas can be air or any other available gas. In both cases, in addition, the substrate may be preheated within the vacuum chamber or prior to introduction into the vacuum chamber to a temperature less than the melting point of the metal. The preheating temperature should be at least several hundred degrees, however.
Ceramic coating is effected in accordance with the present invention, by juxtaposing two electrodes of different metals, preferably a highly conductive and a highly refractory metal with a substrate which is preferably a ceramic body, and striking an arc between these electrodes in an evacuating chamber containing the electrodes and the substrate. According to the invention, the electrodes are first given a relative polarity, i.e. one is poled positively while the other is poled negatively to deposit the metal from one of these electrodes selectively while at the same time, it appears, depositing a small amount of this latter metal on the second electrode.
When polarity is then reversed, the metal vaporizes preferentially prom the second electrode, initially including the small portion of the metal from the first electrode which is deposited thereon so that at the interface between the two layers a mixed composition of the metals is formed.
The disadvantages, which have hitherto been encountered when high conductlvlty~metals, especially copper but also gold and silver, are applied to a ceramic substrate with respect to : :
; adhesion and especlally~with respect to adhesion after or during soldering or other welding ox conductivity elements thereto, oan~be obviated if, prior to the application of the high conduct 3 ~iVlty metal, the ceramic is coated with a refractory metaling a comparatively small thickness and this intermediate layer of coating is in turn coated with the conductive metal.
More particularly, it has been found that it is possible to deposit a coating of a thickness of, say, 5 to 10 microns of tungsten, molybdenum, titanium or zirconium as the refractory metal upon the substrate and thereafter to apply a coating of greater thickness, say 0.001 to 0.02 inch of copper of a copper alloy, gold, silver or some other non refractory metal, i.e. metal having a substantially lower boiling point than that of the refractory metal which is used.
It has been found that, when a two-electrode method is used, according to the invention, it is possible to keenest-lute one electrode as the refractory metal and the other elect trove as the non refractory metal and by regulating the polarity of the electrodes during the deposition, the particular metal i which is deposited can be controlled.
With the present invention, it has been found that it is possible to increase the adhesion, in terms of the force no-squired to separate the coating from the substrate by 100 or more times, all other things being equal, when the thin refract tory metal Catalina is applied between the copper coating and the ceramic substrate.
A ceramic substrate can be used in accordance with the present invention and masking techniques can be employed to ensure the formation of the deposit in any desired pattern.
According to an important feature of the invention, one of the two electrodes which are juxtaposed with the substrate can be moved out of alignment with the other electrode and no-; placed by a substitute electrode and the process repeated with ' the latter to additionally deposit at least a layer of the meatloaf the third electrode upon the second layer.
Brief Description of the Drawing __ The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompany-in drawing in which:
FIG. 1 is a diagram in elevation Al view illustrating an apparatus for carrying out vapor deposition in accordance with an embodiment of the present invention;
FIG. 2 is a similar view of another apparatus wherein, however, the vapor deposited material is collected on a vertically reciprocal electrode;
FIG. 3 is a vertical section, also in diagrammatic form, illustrating an apparatus for depositing material upon a substrate disposed below the pool of metal;
Jo FIG. 4 is a view similar to FIG. 3 illustrating :
another embodiment of the invention;
FIG. 5 is an axial cross-sectional view of another Jo 20 apparatus for depositing material upon a substrate according to I-; this invention;
FIG. 6 Sian axial cross-sectional view of a highly compact portable apparatus for carrying out the method of the invention FIG. issue a diagrammatic cross sectional view of another apparatus for carrying out the present invention;
: FIG. 8 is a diagrammatic section illustrating the application of the invention to the coating of a quartz crucible or use in the production of semiconductor wafers;
Jo : :
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US
FIG. 9 is a view of still another device diagram-tidally illustrating the application of large area coatings to ceramic substrates according to the invention;
FIG. 10 is a diagram of an apparatus for carrying out the ceramic-coating method of the present invention;
FIG. 11 is a cross-sectional view drawn to a larger scale of a product of the present invention;
FIG. 12 is a view similar to FIG. 10 but illustrating another apparatus for carrying out the invention;
FIG. 13 is a diagram showing an effect obtained during the deposit of the metal for the first layer before the commencement of the second layer; and FIX. 14 is a cross-sectional view through the product in the latter case.
,:
Specific Description In FIG. 1 there is shown a system utilizing a simple !
arc method in accordance with the present invention for obtaining mirror-like protective coaxings upon substrates or for evaporate ing~various metals or metal alloys, including heat-resistant ; 20 and refractory metals, to apply coatings thereof to the substrate.
As is apparent from FIG. 1, the basic apparatus can include a vacuum chamber, not shown, which can be similar to :
the vacuum chamber of FIG. 6 and in which a metal electrode 1 own be fed by an electrode feeder 7 toward an electrode body 2 to form the pool 3 of molten metal with which the arc is struck. ;
; The electrons body 2 is held in a fixture or holder 5 and the direct-current source applies the arc current across the electrode 1 and the body 2 via a conventional art stabilizing circuit represented at 8.
I US
It has been found to be advantageous to provide the relatively small cross-section electrode 1 with a thermal regular ion 6 tending to prevent, overheating of this electrode Since the cross section of body 2 is substantially larger than that of the electrode 1, the pool 3 lies in a concave recess formed in situ in the body 2.
Jo The apparatus of FIG. 1, utilizing electrodes Lund 2 of titanium, aluminum, tungsten, tantalum or copper, strikes an arc at a temperature of 5000 to 7000F to generate vapor of the metal of the pool 3 which traverses the distance of 10 to 15 cm to the substrate 10 and forms a coating of the metal thereon.
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The pool 3 can be formed by a mixture of metal contributed by the electrodes 1 and 2, thereby depositing an alloy of the metals ; of the two electrodes upon the substrate. Preferably the elect strode lo composed of titanium while the molten metal predominantly consists of aluminum, tungsten, tantalum or copper.
The apparatus of FIG. 1, without substantial midlife-cation, can be utilized in a non crucible method of generating protective coatings of carbides, for producing solaced coatings on the substrate or for forming carbide or solaced and even silicon carbide layers upon the substrate. To deposit silicon carbide-tungsten carbide layers on the substrate, electrode 2 is composed ox graphite and electrode 1 of tungsten solaced, The vacuum is initially drawn to 10 6 torn and maintained at 10 5 torn or lower Roy direct current arc-generating voltage ; is 100 volts and the arc current 150 amperes. The deposit forms at a rate of about 0~2 grams per minute.
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s In this case, the apparatus of FIX. 1 is used, again in the usual]. vacuum chamber, although the electrode 1 can be composed of silicon or carbon while the electrode 2 is composed of a metal whose solaced or carbide is to be formed or, in the case of a deposit of silicon upon the sub-striate, can also consist of silicon.
For example, when a silicon carbide deposit upon the substrate 10 is desired, the electrode 1 may consist of silicon while the electrode 2 is a carbon block in which a pool 3 of silicon and solubilized carbon is received.
The vapors are transferred to the substrate and Jo deposited in a silicon carbide layer thereon. The substrate may be titanium and the deposit formed on the substrate may be a mixture of titanium solaced and titanium carbide.
Alternatively, when the electrode 1 is composed of silicon or carbon, and the electrode body 2 is composed of titanium, titanium carbide or solaced can be deposited on a substrate of a different composition.
When a slight oxidizing atmosphere is provided in the evacuated chamber, silicon dioxide deposits are formed on the substrate.
Obviously the apparatus of FIG. 1 is particularly effective in the production of semiconductors.
The th~ermoregulator 6 may be duplicated along the length of the electrode 1 and additional thermoregulators may . .
be provided for the electrode body 2 to prevent overheating , :
thereof.
When either the electrode 1 or the body 2 is come , :
posed of silicon and the other is composed ox carbon, silicon !
carbide is generated by the reaction and deposits in a higher purity than that of the original silica and carbon.
Jo :
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When both of the electrodes are composed of silicon, high density silica and silicon deposits can be obtained as is particularly desirable for the coating of semiconductors.
The apparatus of FIG. 2 is generally similar to that of FIG. 1 but operates under somewhat different principles, the evaporation being effected at least in part from the wetted upper electrode 101.
In this Figure, elements which correspond to those of FIG. 1 utilize similar reference numerals differing in the hundreds position.
In FIG. 2, the electrode feeder 107 is coupled with a vertical reciprocator 112 which imparts a reciprocation to the electrode 101 in the direction of the arrow 114 so as to periodic gaily plunge the tip of the electrode 101 into the pool 103 of the molten metal formed in the electrode body 102.
Upon rising from this pool to restrike the arc I04, the coating 113 of molten metal upon the electrode lulls evapora-ted and the deposit is formed upon the substrate 110.
The electrode body 102 is shown in the holder I05 and the arc current supply is formed by the direct current source I, 109 and the stabilizer 108 in the manner described, the electrode 101 being provided with the thermoregulator 106.
This system has been found to be particularly effect live, in a modification of the foregoing example, when the electrode 101 is composed of titanium and the pool 103 is formed of aluminum.
In FIG. 3 there is shown an embodiment of the invent lion in which the vapor is deposited upon a substrate 210 disk posed below a crucible 217 in the form of an upwardly open 3 ring containing the molten metal 203, the crucible being mounted -I in a holder or frame 205.
I
Here the upper electrode 201 is in the form of a spheric eel segment which functions as a reflector so that, when an arc 204 is struck between the electrode 201 and the melt in the crucible 217, the vapors pass upwardly as represented by the arrows 219 and are reflected downwardly to focus upon the sub-striate 210 as represented by the arrows 218.
The direct current source 209 is here connected across the electrode 201 and the crucible 217 via the arc stabilizer 208 and the upper electrode 201, mounted on the rod 216, is Yen-tidally positioned by the feeder 207 and horizontally positioned by an auxiliary mechanism 215 which adjusts the position of the electrode 201 over the evaporating metal.
In this embodiment, the electrode Sol can be composed of titanium, molybdenum or tungsten while the molten metal can be composed of aluminum or copper and the crucible 217 of gray White.
In FIG. 4 there is shown another embodiment of the invent lion in which the vapors flow downwardly to deposit upon the substrate 310.
Z In this oases the upwardly open crucible 317 containing the molten metal 303 can be supplied with additional molten metal from a ladle or other sources represented at 322 or with solid metal which is melted in the crucible 317. The latter can be Jo heated by auxiliary means such as an inductive heater 323 and is supported in a holder 305.
Jo : The bottom of the crucible 317 is formed with apertures 321 at which droplets of the molten metal appear, these droplets being vaporized by the arc 304 struck between the electrode 301 ~'~ and the bottom of the crucible 317.
The temperature in the region of the arc can be con-trolled by an auxiliary inductive means 324 and the electrode 301 can be cooled as represented by the cooling element 306.
Electrode 301 is fed toward the crucible 317 by the electrode holder 307 and the arc is maintained by an arc stab-liver 308 connected to the direct current source 309.
In this embodiment, the molten metal may be copper.
In place of the auxiliary device 324, a substrate to be coated may be provided at this location, e.g. in the form of a titanium ring, which can collect the vapor in the form of a coat-in.
The embodiment of FIG. 5 evaporates the molten metal as , it is formed in a closed space, the vapors being discharged through apertures 425 on the substrate 410.
In this case, the pool of liquid is formed by melting ;
the electrode 402 supported by the holder 405 by feeding the I, counter electrode 401 via the electrode feeder 407 through a central bore 426 in the electrode 402, the electrode 401 passing through an insulating sleeve 427 forming a guide. A temperature regulator 406 lo provided coccal around the two electrodes adjacent the arc 404 to prevent overheating in the region ahead of the apertures 425. The deposit is formed on the substrate 410.
The current is supplied between the electrodes through I; the arc stabilizer 408 and the direct current source 409 in the manner described previously.
FIG. 6 shows a portable voltaic arc device for~depositlng 'I; reflective anticorrosive, protective and semiconductor type metal, silicide~and carbide coatings using the principles dyes cried previously.
This apparatus comprises a vacuum chamber 500 which is :
formed at its upper end with a handle 530 enabling the portable unit to be readily transported.
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Within this chamber, there is provided a hollow sphere 517, the lower part of which forms a crucible for the molten metal 503, coated internally with a high-temperature heat nests-lent (refractory) material such as aluminum oxide.
The upper portion of this sphere is coated at 531 with a reflective layer concentrating the heat reflected from the bath back onto the latter.
An arc 504 is struck between an electrode 501 and the bath 503, the electrode being fed by the unit 507 toward the bath as the electrode material is consumed.
Additional metal, e.g. in solid form, is fed to the bath as a rod 532 which also is connected to the feeder 533 ' so that as the bath is consumed, additional metal is supplied thereto.
The electrode 501 and the bath 503 are connected to opposite terminals of an arc stabilizer and a direct current source in the manner previously described.
A tubular electrode 502 surrounds the rod 532.
The lower part of the chamber 500 is provided with an air pump as represented at 533, the latter evacuating the chamber - 20 containing the hollow sphere 517 and, via a vacuum hose 534, via a valve 535, an adapter 536 of outwardly divergent configure-lion which can be connected to a lateral aperture 525 of the hollow sphere 517.
` The adapter 536 can be formed with a heating coil 537 to prevent undesired condensation of vapor thereon.
. .
Between the aperture 525 and the adapter 536 there is provided a vacuum lock 538 and a mounting arrangement 539 for holding a variety of adapters of different shapes and sizes.
The adapter 536 is also formed with a vacuum gasket 5~0 3 whereby the adapter can bear against the substrate 510 to be coated.
;
s The portable unit shown in FIG. 6 is carried to the location of the substrate 510 to be coated and the appropriate adapter 536 is mounted on the fitting 539 and the gasket 540 pressed against the surface 510 to be coated. The arc current is supplied and the system is evacuated by the air pump 533, thereby melting the metal and forming the bath 503 within the hollow sphere. The gate 538 is then opened and the vapors per-milted to pass onto the substrate 510 at least in part by pressure differential as controlled by the valve 535 maintained between the interior ox the sphere 517 and the adapter 536.
Practically any product at any site can be coated and the use of a variety of adapters of different shapes and sizes enables coating of even intricate bodies without moving them from the area in which they are to be used. The device can be collapsible so as to be used to provide coatings inside ducts and the like.
The apparatus shown in the drawing, without the adapter 536, can be used as a propellant for individuals or equipment in space.
20~ Upon generation of the arc, one need only open the gate 53~ to discharge a stream through the aperture 525 and effect propulsion in the opposite direction. The vacuum in spate provides a natural vacuum for the device and no air pump 533 is then required Practically any waste found in space applications can be utilized in the vessel 517 to generate such propulsion.
In FIG. 'Thor is shown an embodiment of the invention , which combines features previously described and concepts developed above.
In this system, which can be used to deposit a coating 3 610' on the inter surface aye of a tube 610, forming a sub-striate, of complex shape, a material-supplying electrode 602 of corresponding shape is mounted centrally of the tube on a support I S
aye and is provided with an induction heating coil aye of a temperature controller 606 which can have a thermocouple 606b or a like temperature sensor responsive to the temperature of the material-supplying electrode 602 for maintaining the tempera-lure of the latter constant in the range of 800 to 1000F by conventional feed-back control circuitry.
As in the previous embodiment, the substrate and the source of the material to be deposited on the substrate are en-closed in a vacuum chamber 600 which can be evacuated to 10 6 torn so that vapor deposition can be effected at a pressure of 10-5 torn.
The end of the material-supplying electrode 602 is provided with an arc-striking electrode 601 which can be respire-acted toward and away from the electrode 602 by an electrically controlled reciprocating drive 607~ The latter can be operated in response to a zero current detector aye so that when the arc current decays completely, the electrode 601 is displaced to the Jo left into contact with the end aye of the electrode 602 and is then withdrawn to reestablish an arc. The arc current is pro-voided by a pulsating direct current source 609 across which an arc stabilizer 608 the parameters of the arc current and arc :~:
voltage are adjusted within the range of 50 to 90 amperes and 30 to 60 volts by these circuit elements.
In practice, utilizing the system illustrated once the arc is struck, the arc itself, an evaporation effect or some other electromagnetic phenomenon appears to progress as represented by the arrow A generally helical and spiral where ~,~ arc-striking location and vapor deposition takes place over the entire length of the ~aterial-supply electrode 602 which is sub-jetted to this phenomenon, i.e. over the length at which the phenomenon is effective until the arc decays.
I' :
The material loss from the electrode 602 gradually transforms it into a tapered shape as represented by the dot--dash lines as 602b in FIG. 7.
The fact that the taper results in a recession of the electrode from the substrate does not create any problem of significance because the greatest deposit is at the region of greatest recession and consequently, the ultimate coating as it progresses along the substrate is highly uniform.
The system of the invention is especially useful in coating temperature-sensitive materials with very small thick-messes of coating material since the coating is especially rapid and it is possible to carry out the deposition without significantly heating up the substrate.
A copper electrode 602 of the shape shown is prove-Dodd Inca substrate tube with an initial spacing of electrode 602 from the substrate of about 10 cm. The electrode is main-twined at a temperature of 900F and an arc is struck in the manner previously described at one end. The arc current is about 70 amperes and the voltage applied after the electrode 601 is withdrawn to form the arc is about 40 volts. The speed of evaporation from electrode 602 under these conditions ox-coeds the speed of evaporation in Example 1.
; In FIG. theorization an arrangement for applying a silicon coating 710' to a quartz crucible 710 of the type utilized for the melting of silicon and from the melt of which a monocrystalline bar of silicon can be drawn for subsequent slicing into silicon wafers and use in the semiconductor in-dusty. According to the invention, the interior surfaces of 3 the crucible are sandblasted and the crucible is preheated, :;; :: :
- ' Lo e.g. to a temperature of 200 to 600C before the crucible is placed in the vacuum chamber. A pair of silicon electrodes 701 and 702 are juxtaposed with one another within the crucible and, utilizing the electrode reciprocating means of the type shown at 607, the electrodes are brought together and then separated as represented by the arrows aye and 707b so they touch and then are drawn apart to stroke the arc. The power supply which can also be of the type described is represented at 709. The arc current can again be 50 to 90 amperes and the arc voltage some 30 to 60 volts. A substantially uniform highly adherent silicon coating can be obtained, especially when the silicon is initially heated, e.g. by means similar to that utilized in the embodiment of FIG. 7.
When a nitrogen atmosphere is released in the region of the arc, the deposit is of the silicon nitride Sweeney. When ' one of the electrodes is composed of carbon, a silicon carbide , deposit is-formed. The same system can be used for coating `'~ any substrate with pure So or one of the other coatings mentioned.
After the initial arc is produced the electrodes can be cooled.
In FIG. there is shown a system for the large area coating of a ceramic substrate 801 which prior to introduction into the vacuum chamber can be initially preheated, after its ; coating-receiving surface has been sandblasted, by the movement of a burner 820 along the underside of the substrate. The elect trove 801 can be composed of a refractory metal or nickel and via the actuator 807 is urged into contact with and withdrawn from contact from the counter electrode 802 which may also be composed of the same metal.
:
The power supply has been represented at 809. The 3 electrodes are here mounted on a track 821 and are moved along the substrate so that as the arc is repeatedly struck and the I
, ~3~9~
arc travels along the electrode 801 in the vacuum chamber receive in the entire assembly, the entire surface of the substrate is coated utilizing the principles described in FIG. 7.
E pie Utilizing an apparatus operating with the principles shown in FIG. 9, an aluminum oxide plate is coated to a thick-news of` l to 2 miss with tungsten utilizing tungsten electrodes.
The arc current is 50 amperes and the arc voltage 40 volts for a maximum electrode spacing of' approximately 4 mm. The electrode diameter was about l cm. The tungsten coating was highly ad-hornet to the alumina plate.
FIG. 10 shows an apparatus, in a highly diagrammatic form, for carrying out the method of the invention. This Papa-fetus comprises a chamber 1010 which can be evacuated by a suction pump 1011 to the desired degree of` vacuum, generally lo 5 to 10 6 torn. Within this chamber, by means not shown, a ceramic substrate 1012 can be disposed and can be shielded by a mask diagr~ammatica]ly~illustrated at 1013 so that coating can only occur in regions defined by the windows 1014 in the mask. 'I
Within the vacuum chamber the portion of the substrate to be coated is juxtaposed with a pair ox electrodes, i.e. a copper electrode 1015 and a tungsten electrode 1016, the elect triodes being provided with means such as the electromagnetic motors (solenoids) 1017 and 1018 for briefly bringing them into contact to strike the arc and then drawing them apart. The purser or periodically energizing the devices 1017 and 1018 have been shown at loll.
I: :
~3~3q~
The power supply comprises the alternating current source 1020 which is connected to a rectifier 1021 and the latter is provided with a reversing switch 1022 which can no-verse the polarity of the electrodes 1015 and 1016 under the control of a timer 1023.
In operation with the copper electrode 1015 poled positively and the tungsten 16 poled negatively an arc can be struck by passing an electric current of 30 to log amperes at a voltage of 40 to 100 volts through and across the gap after the electrodes briefly touch to preferentially vaporize tungsten and thus deposit tungsten through the window 1014 of the mask 1013 on the substrate. The duration of coating is controlled by the timer 1023 which, after the coating of the order of microns in thickness has been applied, reverses the polarity so that the copper electrode 1015 is now poled negatively and the tungsten electrode 1016 is poled positively whereupon copper is vaporized from the electrode 1015 and deposited upon the substrate.
As can be seen from FIG. 11, the resulting article has a substrate 1030, ego us aluminum oxide, bearing a copper coat-in 1032 which is separated by the refractory metal coating 1031 (tungsten) of smaller thickness.
Example Utilizing the principles described, a current of about , 70 amperes, a voltage of 80 volts and a vacuum of about 10 5 torn, an aluminum ogle plate is coated with tungsten to a thick- ;
news of about 8 microns and with copper to a thickness of about 0.002 inches. The adhesion is measured and for the coating is found to be 500 to 700 lobs per square inch (force required to remove the coating). When under identical conditions a copper I
coating of the same thickness is applied to the same substrate, the adhesion is only 6 to 8 lobs per square inch. The direct copper-to-ceramic bond is found to be sensitive to both mechanic eel and thermal effects when a solder connection is made to it and with the copper/tungsten contact, formed according to the invention, no similar sensitivity was found.
Practically identical results could be obtained by substituting molybdenum, titanium and zirconium for the tungsten and with combinations of these refractory metals with one another and with tungsten as intermediate layers. Similarly, high degrees of' adhesion were obtained with nickel, gold silver and alloys thereof with one another and with copper.
FIG. 12 shows a modification of the apparatus of FIG.
10 in which the chamber 1110, evacuated by the pump 1111, in-eludes a ceramic substrate 1112 which is to be coated with a plurality of metals. In this case, in addition to the common electrode 1116 and its actuator 1118 driven by the pulserltimer 1119, a pair of counter-electrodes 1115 and aye, respectively of copper and gold, are provided each with a respective actuator 1117, aye. The counter-electrode assembly is provided on a track 11124 having a drive enabling shifting of the two electrodes to the left as illustrated by the showing of the electrode 1115 in its shifted position in dot-dash lines. Naturally in the latter position, the electrode aye is aligned with the common electrode 1116. A reversing switch 1122 as described in connect lion with FIG. 10 19 here also provided and the apparatus is energized from the alternating current lines 1120 through the rectifier 1121.
In this mode of operation, once the chamber is evoke 3 ted, the actuators 1117 and 1118 are operated to move the elect troves 1115 and 1116 together and apart to strike an arc, the -22_ I
electrode 1116 of tungsten being poled positively while the electrode 1115 of copper is poled negatively.
This process is continued in the manner described until the initial coating of tungsten has been brought up to the desired thickness.
As can be seen from FIG. 13, this procedure not only results in erosion of the tungsten electrode 1016 but it also gives rise to a small deposit 1025 of tungsten on the copper electrode 1015.
When the polarity is now reversed 7 i.e. the copper electrode 1015 is poled positively and the tungsten electrode is poled negatively, the arc is struck and evaporation is effect ted from the copper electrode, the tungsten deposit 1025, which has been exaggerated in thickness in FIG. 13, vaporizes together with copper and a mixed tungstentcopper deposit is produced as an interface.
In FIG. 14, for example, the substrate 1112 is shown to have been coated at 1131 with the tungsten layer. The mixed or tungsten layer 1126 is then applied thereto before, with con-Tunisian of the generation of vapor by arc-striking between the electrodes 1115 and 1116, the copper coating 1132 is applied.
When the topper coating has reached the desired thick- ;
news, the electrode assembly 1115, 1117 is shifted to the left I:
and replaced Beth assembly aye, aye and the arc is struck between the electrodes aye, 1116 to deposit gold in a layer ; 1133 upon the topper coating.
A controller 1127 may be provided for the electrode shifting device 1124, the pulser/timer 1119 and the reversing switch 1122 and may be controlled by a preprogrammed MicroPro 3 censor to effect the polarity reversal and the switching of electrodes when layer thicknesses of the desired magnitude have been achieved.
eye The method of Example 4 is practiced except that the copper electrode is shifted away and replaced by a gold elect trove. Utilizing the same vacuum and striking a similar arc, a flash coating in the order of the 5 microns range of gold was deposited upon the copper coating under the condition recited for copper deposition.
The adhesion was not diminished and the resulting gold layer was found to make an ideal contact for micro-elec-ironic purposes. Investigations of the interface between copper and tungsten showed mixed transition zone 1126 which was traced to the vaporization of a minor deposit of tungsten from the copper electrode.
.
' :
:
I, : I' ,, ' :
, I:
Claims (28)
1. A method of coating a ceramic with a metal, comprising the steps of:
roughening a surface of a ceramic substrate by subjecting it to blasting with particles;
preheating said substrate to a temperature of at least 200°C but less than the melting point of a metal to be applied thereto;
juxtaposing said surface of said substrate with an electrode composed of said metal;
evacuating the space in which said electrode is juxtaposed with said substrate to at most 10-6 torr and maintaining the pressure in said space substantially no higher than 10-5 torr; and striking an arc with said electrode by intermittently contacting same with another electrode while applying a voltage of substantially 30 to 60 volts across said electrodes and passing a current of substantially 50 to 90 amperes through said electrodes to evaporate the electrode composed of said metal and deposit said metal on said surface.
roughening a surface of a ceramic substrate by subjecting it to blasting with particles;
preheating said substrate to a temperature of at least 200°C but less than the melting point of a metal to be applied thereto;
juxtaposing said surface of said substrate with an electrode composed of said metal;
evacuating the space in which said electrode is juxtaposed with said substrate to at most 10-6 torr and maintaining the pressure in said space substantially no higher than 10-5 torr; and striking an arc with said electrode by intermittently contacting same with another electrode while applying a voltage of substantially 30 to 60 volts across said electrodes and passing a current of substantially 50 to 90 amperes through said electrodes to evaporate the electrode composed of said metal and deposit said metal on said surface.
2. The method defined in claim 1 wherein said ceramic substrate is a quartz crucible.
3. The method defined in claim 2 wherein at least one of said electrodes is composed of silicon, further comprising the step of controlling the temperature of said one of said electrodes to maintain said temperature in the range of substantially 800°F
to 1000°F.
to 1000°F.
4. The method defined in claim 1 wherein said metal is composed of nickel, copper, tungsten, titanium or tantalum.
5. The method defined in claim 4 wherein said ceramic is a body of alumina.
6. The method define din claim 1 wherein a thin layer of a refractory metal is first applied to said substrate and a layer of another metal is applied to said thin layer.
7. The method defined in claim 6 wherein said other metal is a high-conductivity metal.
8. The method defined in claim 7 wherein said high--conductivity metal is copper, gold, silver or an alloy thereof.
9. The method defined in claim 8 wherein said refractory metal is tungsten, molybdenum, titanium, zirconium or an alloy or combination thereof.
10. The method defined in claim 9 wherein said refractory metal is applied to said substrate to a thickness of the order of microns and said high-conductivity metal is applied in thickness of substantially 0.0001 to 0.02 inch.
11. The method defined in claim 10 wherein said high--conductivity metal is applied to a thickness of substantially 0.001 to 0.02 inch and said refractory metal is applied in a layer of 5 to 10 microns.
12. The method defined in claim 11 wherein said high--conductivity metal is copper and said refractory metal is tungsten.
13. The method defined in claim 12 where each of said metals is applied by striking an arc between a respective pair of electrodes to vaporize the respective metal from one of said electrodes in an evacuating chamber.
14. The method defined in claim 14 wherein an electrode of said refractory metal is juxtaposed with an electrode of said high-conductivity metal, said electrodes are brought into contact and drawn apart to strike said arc and said electrodes are initially energized with positive and negative polarities in one sense to initially deposit said refractory metal on said substrate and the polarity is thereafter reversed to deposit said high conductivity metal upon said substrate.
15. A ceramic body comprising a ceramic substrate having a thin refractory metal bonded thereto in a first layer and a second relatively thick layer of a high-conductivity metal bonded to said first layer as made by the method of claim 6.
16. The method defined in claim 1 which comprises:
juxtaposing a first electrode of a first metal with a second electrode of a second metal with one another and disposing said substrate in vapor-receiving relationship with said first and second electrodes in a chamber;
evacuating said chamber;
striking an arc between said first and second electrodes in said evacuated chamber while applying one electrical polarity to said first electrode and another electrical polarity to said second electrode to selectively vaporize metal from said first electrode and deposit same upon said substrate;
thereafter reversing the polarities of said first and second electrodes and striking an arc between them to selectively deposit metal from said second electrode on the metal from said first electrode previously deposited upon said substrate; and thereafter juxtaposing with one of said electrodes a substitute electrode and striking an arc between said substitute electrode and said one of said electrodes in said chamber to vaporize metal from said substitute electrode and deposit same on said layer of the metal of said second electrode on said substrate.
juxtaposing a first electrode of a first metal with a second electrode of a second metal with one another and disposing said substrate in vapor-receiving relationship with said first and second electrodes in a chamber;
evacuating said chamber;
striking an arc between said first and second electrodes in said evacuated chamber while applying one electrical polarity to said first electrode and another electrical polarity to said second electrode to selectively vaporize metal from said first electrode and deposit same upon said substrate;
thereafter reversing the polarities of said first and second electrodes and striking an arc between them to selectively deposit metal from said second electrode on the metal from said first electrode previously deposited upon said substrate; and thereafter juxtaposing with one of said electrodes a substitute electrode and striking an arc between said substitute electrode and said one of said electrodes in said chamber to vaporize metal from said substitute electrode and deposit same on said layer of the metal of said second electrode on said substrate.
17. The method defined in claim 16 wherein said first electrode is composed of a refractory metal.
18. The method defined in claim 17 wherein said refractory metal is selected from the group which consists of tungsten, molybdenum, titanium, zirconium and alloys and combinations thereof.
19. The method defined in claim 17 wherein at least one of said second and substitute electrodes is composed of a metal selected from the group which consists of nickel, copper, gold, silver and alloys thereof.
20. The method defined in claim 16 wherein the layer of the metal of said first electrode is applied in a thickness of the order of microns and the layer formed by one of said second and substitute electrodes has a thickness of 0.001 to 0.02 inches.
21. The method defined in claim 1 which comprises the steps of:
juxtaposing a pair of electrodes of different metals with said substrate in a chamber;
evacuating said chamber;
applying one electrical polarity to one of said electrodes and the opposite electrical polarity to the other of said electrodes and striking an arc between said electrodes by approximating them into contact and drawing them apart to vaporize material from said one of said electrodes and deposit the vaporized material on said substrate in a first layer while simultaneously transferring a portion of said material from said one of said electrodes onto the other of said electrodes; and thereupon reversing the electrical polarities of said electrodes and striking an arc between them to vaporize material from said other electrode including said portion and deposit a mixed layer of materials from both of said electrodes on said first layer as a transition layer and thereafter deposit material from said second electrode onto said transition layer.
juxtaposing a pair of electrodes of different metals with said substrate in a chamber;
evacuating said chamber;
applying one electrical polarity to one of said electrodes and the opposite electrical polarity to the other of said electrodes and striking an arc between said electrodes by approximating them into contact and drawing them apart to vaporize material from said one of said electrodes and deposit the vaporized material on said substrate in a first layer while simultaneously transferring a portion of said material from said one of said electrodes onto the other of said electrodes; and thereupon reversing the electrical polarities of said electrodes and striking an arc between them to vaporize material from said other electrode including said portion and deposit a mixed layer of materials from both of said electrodes on said first layer as a transition layer and thereafter deposit material from said second electrode onto said transition layer.
22. The method defined in claim 21 wherein said substrate is a ceramic.
23. The method defined in claim 22 wherein the material of said one of said electrodes is a refractory material.
24. The method defined in claim 23 wherein said refractory metal is tungsten, molybdenum, zirconium or an alloy or combination thereof.
25. The method defined in claim 22 wherein said other electrode is composed of nickel, copper, gold, silver or an alloy thereof.
26. The method defined in claim 25 wherein said one of said electrodes is composed of tungsten.
27. The method defined in claim 22 wherein said other electrode is thereafter shifted out of alignment with said one of said electrodes and is replaced by a substitute electrode with which an arc is struck in said chamber to deposit a further material on said material of said electrode.
28. A body made by the method of claim 6.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/614,434 US4505948A (en) | 1983-05-13 | 1984-05-25 | Method of coating ceramics and quartz crucibles with material electrically transformed into a vapor phase |
| US06/626,056 US4537794A (en) | 1981-02-24 | 1984-06-29 | Method of coating ceramics |
| US626,056 | 1984-06-29 | ||
| US06/667,641 US4596719A (en) | 1981-02-24 | 1984-11-02 | Multilayer coating method and apparatus |
| US667,641 | 1984-11-02 | ||
| US614,434 | 1990-11-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1238295A true CA1238295A (en) | 1988-06-21 |
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ID=27417126
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000476016A Expired CA1238295A (en) | 1984-05-25 | 1985-03-07 | Method of coating ceramics and quartz crucibles with material electrically transformed into a vapor phase |
Country Status (8)
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|---|---|
| JP (1) | JPH03158478A (en) |
| CA (1) | CA1238295A (en) |
| DE (1) | DE3508690A1 (en) |
| FR (1) | FR2564865B1 (en) |
| GB (2) | GB2167774B (en) |
| IL (1) | IL74360A (en) |
| IT (1) | IT1200418B (en) |
| SE (1) | SE8501281L (en) |
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|---|---|---|---|---|
| DE3930832A1 (en) * | 1989-09-15 | 1991-03-28 | Nishibori Mineo | DEVICE AND METHOD FOR COATING WORKPIECES BY ARCH DISCHARGING |
| EP0531527B1 (en) * | 1991-03-27 | 1998-01-14 | Institut Elektrosvarki Imeni E.O.Patona Akademii Nauk Ukrainskoi Ssr | Method and device for plasma-detonation working of metal articles |
| DE19845804C2 (en) * | 1998-09-30 | 2000-11-30 | Tacr Turbine Airfoil Coating A | Method and arrangement for heating metal components with electron radiation in a vacuum chamber |
| US20070026205A1 (en) | 2005-08-01 | 2007-02-01 | Vapor Technologies Inc. | Article having patterned decorative coating |
| CN105506561B (en) * | 2015-12-25 | 2018-05-18 | 中国航空工业集团公司北京航空制造工程研究所 | Inhibit the method for edge effect in blade erosion resistance coating preparation process |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE419531A (en) * | 1936-02-01 | |||
| DE676733C (en) * | 1937-02-07 | 1939-06-10 | Siemens & Halske Akt Ges | Evaporation of alloys in a high vacuum |
| NL291753A (en) * | 1963-04-19 | |||
| GB1257015A (en) * | 1967-11-03 | 1971-12-15 | ||
| LU58252A1 (en) * | 1968-03-22 | 1969-07-11 | ||
| BE769262A (en) * | 1971-06-29 | 1971-12-29 | Centre Rech Metallurgique | PROCESS FOR DEPOSITING A STAINLESS NICKEL-CHROME COATING. |
| US3793179A (en) * | 1971-07-19 | 1974-02-19 | L Sablev | Apparatus for metal evaporation coating |
| CA960922A (en) * | 1971-12-27 | 1975-01-14 | Airco | Vapor deposition process |
| US3889632A (en) * | 1974-05-31 | 1975-06-17 | Ibm | Variable incidence drive for deposition tooling |
| DE2450834C3 (en) * | 1974-10-25 | 1984-06-28 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | Method for aluminizing the inside of the screen pan of a television picture tube |
| CH619344B (en) * | 1977-12-23 | Balzers Hochvakuum | PROCESS FOR PRODUCING GOLD-COLORED COATINGS. | |
| CH640886A5 (en) * | 1979-08-02 | 1984-01-31 | Balzers Hochvakuum | METHOD FOR APPLYING HARD WEAR-RESISTANT COATS ON DOCKS. |
| JPS5635768A (en) * | 1979-08-30 | 1981-04-08 | Inoue Japax Res Inc | Vapor depositing apparatus |
| JPS5635767A (en) * | 1979-08-30 | 1981-04-08 | Fuji Kinzoku Kako:Kk | Basket type electrostatic plating apparatus and plating method |
| CH624817B (en) * | 1979-09-04 | Balzers Hochvakuum | PROCESS FOR PRODUCING GOLD-COLORED COATINGS. | |
| DE3152736C2 (en) * | 1981-02-23 | 1984-04-05 | Leonid Pavlovič Sablev | Self-consuming cathode for an arc metal evaporator |
| US4351855A (en) * | 1981-02-24 | 1982-09-28 | Eduard Pinkhasov | Noncrucible method of and apparatus for the vapor deposition of material upon a substrate using voltaic arc in vacuum |
| US4609564C2 (en) * | 1981-02-24 | 2001-10-09 | Masco Vt Inc | Method of and apparatus for the coating of a substrate with material electrically transformed into a vapor phase |
| US4438153A (en) * | 1981-02-24 | 1984-03-20 | Welbilt Electronics Die Corporation | Method of and apparatus for the vapor deposition of material upon a substrate |
| JPS5881976A (en) * | 1981-11-06 | 1983-05-17 | Toru Mashida | Preparation of decorative body |
| JPS58136775A (en) * | 1982-02-08 | 1983-08-13 | Hitachi Ltd | Method and device for vapor deposition |
| JPS5950177A (en) * | 1982-09-16 | 1984-03-23 | Kobe Steel Ltd | Surface treatment of metal giving superior adhesive property |
| AT376460B (en) * | 1982-09-17 | 1984-11-26 | Kljuchko Gennady V | PLASMA ARC DEVICE FOR APPLYING COVERS |
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1985
- 1985-02-17 IL IL74360A patent/IL74360A/en unknown
- 1985-03-05 GB GB08521329A patent/GB2167774B/en not_active Expired
- 1985-03-07 CA CA000476016A patent/CA1238295A/en not_active Expired
- 1985-03-08 GB GB08506046A patent/GB2159540B/en not_active Expired
- 1985-03-12 DE DE19853508690 patent/DE3508690A1/en not_active Withdrawn
- 1985-03-12 FR FR8504056A patent/FR2564865B1/en not_active Expired
- 1985-03-15 IT IT19918/85A patent/IT1200418B/en active
- 1985-03-15 SE SE8501281A patent/SE8501281L/en not_active Application Discontinuation
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1990
- 1990-10-19 JP JP2279519A patent/JPH03158478A/en active Pending
Also Published As
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|---|---|
| GB8521329D0 (en) | 1985-10-02 |
| IL74360A (en) | 1989-01-31 |
| SE8501281L (en) | 1985-11-26 |
| GB2159540B (en) | 1988-10-05 |
| DE3508690A1 (en) | 1985-11-28 |
| IT8519918A0 (en) | 1985-03-15 |
| SE8501281D0 (en) | 1985-03-15 |
| GB8506046D0 (en) | 1985-04-11 |
| GB2167774B (en) | 1988-10-05 |
| JPH03158478A (en) | 1991-07-08 |
| FR2564865A1 (en) | 1985-11-29 |
| FR2564865B1 (en) | 1988-01-15 |
| GB2167774A (en) | 1986-06-04 |
| IL74360A0 (en) | 1985-05-31 |
| GB2159540A (en) | 1985-12-04 |
| IT1200418B (en) | 1989-01-18 |
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