Classifications

• • 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
  • C23C14/50—Substrate holders
  • C23C14/505—Substrate holders for rotation of the substrates
• • 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
  • C23C14/34—Sputtering
  • C23C14/3492—Variation of parameters during sputtering

Definitions

• Embodiments of the present subject matter generally relate to the deposition of reactively sputtered thin films on substrates.
• Exemplary films may be composed of two or more elements including, but not limited to, metal oxides, nitrides and carbides utilized to form non-scattering coatings, scattering coatings, and wear coatings.
• Exemplary substrates may be, but are not limited to, tungsten-halogen incandescent lamps, solar mirrors, lamp reflectors, lamp burners, and drill bits.
• Prior art coating systems for these substrates generally utilize magnetron sputtering systems.
• Figures 1 and 2 are perspective views of prior art magnetron sputtering systems.
• conventional magnetron sputtering systems utilize a cylindrical, rotatable drum 2 mounted in a vacuum chamber 1 having sputtering targets 3 located in a wall of the vacuum chamber 1.
• Plasma or microwave generators 4 known in the art may also be located in a wall of the vacuum chamber 1.
• Substrates 6 may be removably affixed to panels or substrate holders 5 on the drum 2.
• a plurality of substrates 6, such as lamp burners may be attached to the rotatable drum 2 via a conventional substrate holder 8.
• Conventional substrate holders 8 generally include a plurality of gears and bearings 9 allowing one or more lamps 6 to rotate about its respective axis.
• Material from the sputtering target 3 may thus be distributed around the lamps 6 as they pass a target 3. Obtaining sufficient uniformity in coating generally requires plural rotations past the target 3.
• Sputtering systems according to embodiments of the present subject matter may move the substrates rapidly and/or repeatedly past the sputtering target so as to limit the material deposited in a single pass to no more than a few atomic mono-layers, and often less than one. Exemplary single-pass material thicknesses may range from about one to thirty angstroms.
• Oxidation may be generally defined as the loss of one or more electrons by an atom, molecule, or ion during a chemical reaction. Oxidation is generally accompanied by an increase in the oxidation number on the atoms, molecules, or ions that lose electrons. In embodiments of the present subject matter, oxidation may be completed in other parts of the respective vacuum chamber during the intervals between deposition passes. Oxidation in embodiments of the present subject matter may be conducted with or without the aid of a highly oxidizing source, e.g., a microwave-driven plasma.
• a highly oxidizing source e.g., a microwave-driven plasma.
• Moving substrate holders may be provided to allow the flux from a sputtering target to be distributed over an area larger than the projected area of the substrates onto the sputtering target plane.
• an exemplary deposition process may be operated at a higher sputtering rate thereby resulting in an increased throughput of coated substrates.
• moving substrate holders may be provided to allow the flux from one or more sputtering targets to be nearly evenly distributed over the substrates by properly phasing the orientation of the substrates during deposition passes by the sputtering targets.
• an exemplary deposition process may be operated at a higher sputtering rate thereby resulting in an increased throughput of coated substrates.
• One embodiment of the present subject matter therefore provides a novel method of increasing the volume of non-absorbing thin film formed per unit of time.
• the method comprises increasing the area of a substrate surface by a factor of x, and increasing the rate of deposition of the target material by a factor greater than the inverse of x to thereby increase the rate of formation of the volume of non-absorbing thin film per unit of time.
• Another embodiment of the present subject matter provides a method of forming a non-absorbing thin film on a surface of a substrate.
• the method comprises operating a sputtering target at a first sputtering rate of target material and exposing the substrate surface to the target at a first exposure rate to effect the deposition of the sputtered target material on the surface of the substrate at a deposition rate per unit of area of substrate surface.
• the rate of exposure of the substrate surface to the target may then be increased, and the sputtering target operated at a second sputtering rate of target material so that the deposition rate of sputtered target material per unit of area of substrate surface is greater than the product of the ratio of the first exposure rate of substrate surface to the increased exposure rate of the substrate surface and the deposition rate per unit of area of substrate surface.
• a further embodiment of the present subject matter provides a coating system having a source of material to be deposited having a selective rate of release of the material, a reactive atmosphere for exposing the deposited material to a reactive agent to effect oxidation of the material, tooling for holding one or more substrates, the tooling having a capacity determining a first surface area of the substrates held thereby, and a carrier supporting the tooling for exposing the substrates held by the tooling to the source of deposition material and the reactive atmosphere at a first area per unit of time to thereby effect a first rate of depositing material per unit area of substrate.
• a method of increasing the rate of formation of substantially non-absorbing thin film on the one or more substrates may comprise increasing the capacity of the tooling to thereby increase the surface area of substrates held by the tooling, and increasing the area of the substrates exposed to the source of deposition material and the reactive atmosphere per unit of time.
• the rate of release of the material from the source may then be increased so that the rate of deposition of the material per unit area of substrate is greater than the product of (i) the ratio of the first area per unit of time exposed to the source of deposition material and the reactive atmosphere to the increased area and (ii) the first rate of depositing material per unit area of substrate.
• An additional embodiment of the present subject matter provides a method for forming thin films on substrates using a coating system wherein a number of atoms of an element are deposited on an area of substrate surface during a coating cycle and reacted with another element to form a thin film at a first rate of formation.
• the method comprises increasing the surface area of the substrate and the number of atoms of the element that are deposited on the substrate surface during a coating cycle, and adjusting one or more process parameters including substrate motion to obtain a rate of formation of the thin film per unit area of substrate surface greater than the product of (i) the ratio of the area of the substrate surface having atoms deposited thereon during a coating cycle to the increased area, and (ii) the first rate of formation of the thin film.
• One embodiment of the present subject matter provides a sputter coating system having a vacuum chamber having a coating station, a substrate carrier adapted for passing a plurality of identical substrates through the coating station, the carrier being configured to carry a first number of substrates, a means for introducing a reactive gas into said vacuum chamber at a predetermined rate, a target operating at a first predetermined power level sufficient to create a reactive atmosphere in said coating station and to plasma sputter a selected material onto substrates when passed through said coating station by said substrate carrier, and a plasma generator operating at a predetermined power level for increasing the area, density and reactivity of the reactive atmosphere in the coating station.
• a method for increasing the throughput of substrates in the system may comprise changing the configuration of the substrate carrier to carry a greater number of substrates than the first number, and operating the target at a second predetermined power level, the second power level being greater than the first power level to thereby increase the rate of plasma sputtering of the material onto the substrates.
• Yet another embodiment of the present subject matter provides a sputter coating system having a vacuum chamber, a drum rotatable about its axis for carrying a plurality of substrates mounted thereon within the vacuum chamber, a means for introducing a reactive gas into the vacuum chamber at a predetermined reactive gas introduction rate, a target operating at a target power level sufficient to create a reactive atmosphere in a portion of the chamber and to plasma sputter a selected material onto substrates when carried past the target by the rotating drum, and a plasma generator operating at a plasma generating power level sufficient to create a reactive atmosphere within a portion of the chamber.
• a method of operating the sputter coating system to form a non-absorbing thin film on the substrates may comprise rotating the drum at a selected frequency whereby an increase in the drum rotation frequency will result in an increase in the absorption property of the thin film when the system is operated at the predetermined reactive gas introduction rate, target power level, and plasma generator power level.
• Figures 1 and 2 are perspective views of prior art magnetron sputtering systems.
• Figure 3 is a graphical representation of absorption as a function of power and exposure rate to a sputtering target.
• Figures 4A and 4B are graphical representations of metal deposition pulse pattern with a drum rotation of 30 rpm and target power Pl and a drum rotation of 60 rpm and target power 2*P1, respectively.
• Figure 5 is a graphical representation of absorption as a function of drum rotation rate at constant target power.
• Figure 6 is a graphical representation of a deposition pulse pattern for an area (dA) on a substrate carried on the sputtering system of Figure 2.
• Figure 7A is a pictorial representation of a substrate or substrate carrier rotating clockwise with the clockwise rotation of an exemplary drum.
• Figure 7B is a pictorial representation of a substrate or substrate carrier rotating counterclockwise with the clockwise rotation of an exemplary drum.
• Figure 8 is a perspective view of a sputtering system according to one embodiment of the present subject matter.
• Figure 9 is a block diagram of a further embodiment of the present subject matter.
• Figure 10 is a block diagram of another embodiment of the present subject matter.
• Figure 1 1 is a block diagram of an embodiment of the present subject matter.
• Figure 12 is a block diagram of one embodiment of the present subject matter.
• Exemplary films may include, but are not limited to TiO 2 , rutile TiO 2 , SiO 2 , Tin-doped Indium Oxide, Ta 2 Os, Nb 2 Os, other metals and metal oxides, nitrides and carbides utilized to form non-scattering coatings, scattering coatings, wear coatings, and combinations thereof.
• embodiments of the present subject matter were viewed macroscopically in terms of the area of the sputtering target relative to that of total substrate area to be coated. For rapid motion of the substrate this macroscopic view may be equivalent to spreading the coating thinly over an area much larger than the area instantaneously adjacent the sputtering target thereby enhancing the average oxidation rate and machine throughput.
• an element having an area dA onto which a film is to be deposited may be viewed macroscopically in terms of the area of the sputtering target relative to that of total substrate area to be coated. For rapid motion of the substrate this macroscopic view may be equivalent to spreading the coating thinly over an area much larger than the area instantaneously adjacent the sputtering target thereby enhancing the average oxidation rate and machine throughput.
• the area dA may conceptually be assumed to be a one millimeter square and a portion of a large, flat substrate 6 mounted on a drum 2 in the conventional magnetron sputtering system illustrated in Figure 1.
• the area dA may be a portion of a substrate 6 attached to a rotatable drum 2 via a conventional substrate holder 8 allowing the substrate 6 to rotate about its own axis as illustrated in Figure 2.
• a typical drum 2 may generally be one meter in diameter and one meter in height.
• a one meter by 0.15 meter sputtering target 3 may be mounted in the wall of the system, and the drum 2 may be rotated at any rate, generally between zero and approximately 200 rpm.
• all parts of the substrate(s) may be assumed to possess a coating history identical to that of the area dA.
• variables for the run are drum rotation rate and power to the sputtering target 3. Power generally determines the sputtering rate of metal from the sputtering target 3 and therefore determines the time required to deposit the one micron thick film on an exemplary substrate 6. After each coating run, absorption in the deposited film may be measured.
• Figure 3 is a graphical representation of absorption as a function of power and exposure rate to a sputtering target.
• results from the above experiment are illustrated utilizing two drum rotation rates, 30 rpm and 60 rpm.
• For the 30 rpm rotation rate a low absorption was achieved for powers up to Pi and for the 60 rpm rotation rate, a low absorption was achieved for powers up to P 2 .
• the film became more absorbing in a nonlinear fashion.
• the limiting power for a low absorption is Pi and for a 60 rpm rotation rate, the limiting power for a low absorption is P 2 .
• Pi a nominal 60 minutes was required to deposit the one micron thick film on the area dA and
• the area dA receives a pulse of metal.
• the pulse duration is approximately 50 milliseconds (a "square" spatial distribution of the metal flux from the sputtering target being assumed).
• the pulse duration is approximately 100 milliseconds.
• the amplitude of each pulse, at either the 30 or 60 rpm rotation rates, is generally proportional to the power applied to the target.
• Figures 4A and 4B are graphical representations of a metal deposition pulse pattern with a drum rotation rate of 30 rpm and sputtering target power Pj and a drum rotation rate of 60 rpm and sputtering target power 2*P] or P 2 , respectively.
• These pulse patterns and exemplary processes may be applied to additional tooling and sputtering system configurations exemplified in co-pending and related U.S. Patent Application No. 12/155,544 and may be related to deposition film growth.
• a typical past-the-target rate for SiO 2 is generally lOOA/sec on a flat, non-rotating substrate onto which a non-absorbing film is to be deposited. Therefore, in 50 milliseconds a 5 A layer may be deposited on each pass past the sputtering target.
• a 5 A layer corresponds to approximately one atomic layer. If power (rate) is increased without changing drum rotation rate, the deposited layer thickness during a single pulse may be increased beyond 5 A and absorption increases.
• One response would be to increase drum rotation rate thereby allowing higher power while maintaining the 5 A maximum pulse amplitude, however, if one selects a given power level and measures the absorption as drum rotation rate is increased, the graphical representation illustrated in Figure 5 results.
• Figure 5 is a graphical representation of absorption as a function of drum rotation rate at constant target power. With reference to Figure 5, absorption decreases as drum rotation frequency or rate increases until a minimum is reached at f ⁇ . For drum rotation frequencies beyond f ⁇ absorption increases.
• the illustration of Figure 5 may be explained with continued reference to Figures 4A and 4B. Oxidation of the films deposited by pulses past a sputtering target is conducted in the intervals between the deposition pulses shown in Figures 4a and 4b. This oxidation is aided by a localized oxidation plasma generated by a device 4, e.g., microwave generator, etc., mounted in the sputtering system wall.
• a device 4 e.g., microwave generator, etc.
• the generator 4 may generally be the same width and height of the sputtering target 3. Therefore, an area dA passing through the oxidizing plasma is subjected to an intense oxidizing pulse while passing the generator 4, just as the area dA is subjected to a metal deposition pulse while passing the sputtering target 3.
• the oxidative effectiveness of this auxiliary plasma increases as the oxidizing pulse width increases, that is, as the time the area dA is in the plasma zone increases. While a narrow metal pulse in the deposition zone yields a less absorbing film, just the opposite is the case for the oxidizing plasma pulse.
• increasing the drum rotation rate is productive in the metal deposition zone but counter-productive in the oxidation zone. At a certain rotation rate, then, an insufficient oxidation time exists between metal pulses and absorption increases as the rotation rate increases, as exhibited in Figure 5.
• embodiments of the present subject matter have been described utilizing a sputtering system having tooling allowing one degree of rotational freedom, that is, the rotating drum 2 of Figure 1.
• Exemplary substrates may be, but are not limited to, ellipsoidal tungsten halogen lamps where the ellipsoids are about 2-3 cm in length and approximately one centimeter in diameter. Of course, such an example should not be
• substrates such as solar mirrors, lamp reflectors, lamp burners, and drill bits.
• lamps 6 Two to three thousand such lamps 6, each spinning about its individual axis as the drum 2 rotates, may be mounted in an exemplary sputtering system.
• FIG. 6 is a graphical representation of a deposition pulse pattern for an area dA on a substrate carried on the sputtering system of Figure 2. With reference to Figure 6, five passes of the area dA are conceptually illustrated past an exemplary sputtering target for a drum rotation period of one second.
• pulse shape, width, amplitude and frequency each vary greatly, even at a constant drum rotation rate and constant power to the sputtering target.
• the area dA faces the sputtering target as the individual substrate rotates about its respective axis past the sputtering target. While in other passes, the area dA may be turned away from the sputtering target resulting in no deposition of material on the substrate on the respective pass. Therefore, a given thickness per pass cannot be assigned in this example, as it was for the one degree of rotational freedom example.
• a given exposure per pass through the auxiliary plasma cannot be assigned as the oxidation pulses also vary in shape, width, frequency and amplitude.
• a deposition film layer or nodule uneven in thickness may be deposited on each pass.
• Layers or nodules from a given pass may possess a thickness ranging from zero to several tens of angstroms, with an respective lateral extent dependent upon drum and substrate rotation rates. It should be noted that the location of the deposited layer or nodule may move about the circumference of the substrate from pass to pass; therefore, the non- uniformity in thickness of the deposited film over the entire substrate may be
• a one micron thick film on an exemplary substrate may require two to four thousand passes through the deposition zone.
• a layer or nodule may or may not be deposited on each pass depending upon whether the area dA faces the sputtering target during the pass. With proper phasing from pass to pass, however, a film of substantially uniform thickness may be deposited on the substrate.
• the tooling required to rotate the substrates may be driven in such a manner that every other (e.g., even) substrate rotates clockwise and odd substrates rotate counterclockwise. A one micron film may then be deposited on this array of substrates. If certain conditions are selected, the odd numbered substrates may be highly absorbing while the even numbered substrates are clear, even though the films on both sets of substrates are one micron thick and uniform thereabout.
• Figure 7A is a pictorial representation of a substrate or substrate carrier rotating clockwise with the clockwise rotation of an exemplary drum.
• Figure 7B is a pictorial representation of a substrate or substrate carrier rotating counter-clockwise with the clockwise rotation of an exemplary drum.
• the area dA on the substrate 6 is illustrated as rotating clockwise and entering a flux stream from a sputtering target 3 with an exemplary drum 2 having a clockwise rotational motion.
• the area dA on the substrate 6' is illustrated as rotating counterclockwise and entering a flux stream from a sputtering target 3 with an exemplary drum 2 having a clockwise rotational motion.
• the substrates 6, 6' rotate ninety degrees about their respective axes before their
• Type 1 absorbing oscillators are typically associated with isolated, incompletely oxidized metal atoms, the single pass density of which may be represented by ⁇ j.
• Type 2 absorbing oscillators are generally comprised of isolated pairs of unoxidized metal atoms joined by metal-metal bonds, the single pass density of which may be represented by ⁇ 2 .
• Type 2 oscillators which, due to the need to break the metal- metal bonds, are generally more difficult to oxidize and are formed at higher instantaneous rates of deposition. It should be noted that while production throughput is generally proportional to the average rate, over one drum rotation, absorbing oscillator formation depends on instantaneous conditions as the film is formed adjacent the sputtering target. Thus, when the rate of deposition is low, generally only type 1 absorbing oscillators are created. When the density of type 1 absorbing oscillators becomes high enough, type 2 absorbing oscillators begin to form thereby decreasing the number of type 1 absorbing oscillators during their respective formation.
• type 2 oscillators should be minimized through an analysis and examination of the relationships between process and tooling parameters, substrate rotation rates, substrate rotation directions, sputtering target widths, number of sputtering targets, drum diameter, shape and amplitude of the deposition pattern past the sputtering target(s), masking, phasing of substrate rotation and exposure in the oxidation zone, and cluster tooling.
• the rate of formation of the two types of absorbing oscillators may be represented by a pair of coupled first order differential equations and a pair of non- coupled first order differential equations, one pair for the deposition region and the other for the oxidation region.
• the pairs of differential equations may be represented by the following relationships:
• Equations (1) through (4) generally describe the formation and extinction of the two types of absorbing oscillators, both in the deposition-oxidation zone and in the oxidation-only zone.
• an area dA on a substrate passing in front of a sputtering target and then through an oxidation zone may be considered.
• the substrate e.g., a non-rotating flat, a rotating surface of a lamp, etc.
• metal atoms are deposited on the surface of the substrate at some defined rate. If this rate is low, the metal atoms deposited are single, isolated type 1 absorbing oscillators that then pass through the oxidation zone.
• all the metal atoms deposited on a single pass should be oxidized before the substrate passes in front
• the metal atoms on the surface do not remain as isolated atoms, but begin to form groups of coupled metal atoms and type 2 absorbing oscillators are then present in the coating.
• the type 2 absorbing oscillators begin forming, the density of type 1 absorbing oscillators decreases and the absorption in the film becomes non-linear. This is because the type 2 absorbing oscillators, formed from coupled metal atoms, are more difficult to oxidize than the type 1 absorbing oscillators.
• the metal atoms whether type 1 or type 2 are not fully oxidized before the substrate passes in front of the sputtering target again, the atoms will be buried underneath freshly deposited metal atoms and may become either more difficult or impossible to oxidize thereby leading to the presence of absorption in the deposited film.
• Embodiments of the present subject matter may also be applicable in sputtering systems having tooling allowing at least three degrees of rotational freedom.
• Figure 8 is a perspective view of a sputtering system according to one embodiment of the present subject matter. With reference to Figure 8, an exemplary sputtering system may
• the 16 utilize a substantially cylindrical, rotatable drum or carrier 2 mounted in a vacuum chamber 1 having sputtering targets 3 located in a wall of the vacuum chamber 1.
• Plasma or microwave generators 4 known in the art may also be located in a wall of the vacuum chamber 1.
• the carrier 2 may have a generally circular cross-section and is adaptable to rotate about a central axis.
• a driving mechanism (not shown) may be provided for rotating the carrier 2 about its central axis.
• a plurality of pallets 50 may be mounted on the carrier 2 in the vacuum chamber 1.
• Each pallet 50 may comprise a rotatable central shaft 52 and one or more disks 1 1 axially aligned along the central shaft 52.
• the disks 1 1 may provide a plurality of spindle carrying wells positioned about the periphery of the disk 11.
• Spindles may be carried in the wells, and each spindle may carry one or more substrates, such as a lamp, adaptable to rotate about it respective axis. Additional particulars and embodiments of this exemplary system are further described in co- pending and related U.S. Patent Application No. 12/155,544, filed June 5, 2008, the entirety of which is incorporated herein by reference.
• the first degree of freedom may be defined as the rotation of the drum.
• the second degree of rotational freedom may be defined as the rotation of the substrate, and the third degree of rotational freedom may be defined as the rotation of a planet on which the substrates are mounted.
• certain embodiments of the present subject matter to achieve higher sputtering system throughput by selecting the phasing of rotation to increase the time in an oxidation zone relative to the time in a deposition zone. For example, if a layer or nodule is deposited in a given pass past a sputtering target, it may be desirable to have the phasing in the auxiliary plasma zone so that the layer or nodule has a maximum exposure to the plasma. Such phasing may be accomplished through the design of the rotating tooling fixtures discussed in co-pending and related U.S. Patent Application No. 12/155,544.
• the phasing of the rotation angles past the sputtering target with those in a remote oxidation zone may be important if the oxidizing action in the remote oxidation zone is not isotropic around the substrate.
• the remote oxidizer is an ion gun (highly directional) or if a microwave plasma does not uniformly envelop a respective substrate.
• Selection of the phasing of rotation is important as applied to a single-pass sputtering system. For example, if the single-pass metal coating is uneven around a substrate as the substrate exits the deposition zone, absorption may be present at a greater level due to a greater level of type 1 and 2 absorbing oscillators. Therefore, this uneven coated portion should be oriented toward the oxidizing source as it passes through the remote oxidizing zone.
• inventions of the present subject matter may achieve higher sputtering system throughput by shortening the metal pulse width while increasing the pulse frequency. This may be accomplished by increasing the drum rotation rate, increasing the drum diameter while keeping metal deposition zones constant in spatial width, increasing the substrate rotation rate, increasing the planet diameter and/or rotation rate, and combinations thereof.
• One embodiment of the present subject matter may achieve higher sputtering system throughput by decreasing the deposition pulse frequency while increasing oxidation pulse width and/or frequency using multiple degrees of rotational freedom.
• An additional embodiment of the present subject matter may achieve higher
• Another embodiment of the present subject matter may utilize masking to affect absorption characteristics.
• Masking in coating machines is generally perceived as a means for controlling uniformity of deposited film through shadowing or by deliberately shadowing portions of a substrate according to a predetermined design.
• a predetermined design As the previously described model illustrates, however, anything that affects the shape or magnitude of the metal deposition pattern through which a substrate passes will, when the process is operating on the edge of allowed absorption, change the absorption characteristics of the film. Therefore, embodiments of the present subject matter may provide masking and/or substrate tooling that alters the shape or strength of the deposition pattern in a way that is advantageous with regard to absorption.
• Exemplary masking may be provided in many forms such as, but not limited to, a mask that momentarily blocks metal deposition as a substrate moves through the deposition zone to thereby influence absorption under certain conditions.
• a further embodiment of the present subject matter may achieve higher sputtering system throughput by dividing the sputtering target into two sputtering targets separated by an oxidation zone.
• type 2 absorbing oscillators should be kept as low as possible to optimize film oxidation.
• the sputtering target power i.e., the average coating rate
• P unacceptable absorption commences
• each sputtering target may be operated at a power greater than Pi/2 but lower than P] while maintaining absorption at the level produced
• each of the two sputtering targets may be operated at a lower power than that of a single sputtering target, but the combined power to the two sputtering targets is greater than that allowed with only a single sputtering target thereby resulting in a higher average coating rate.
• An additional embodiment of the present subject matter may also employ exemplary tooling in a disk coating machine as described in co-pending and related U.S. Patent Application No. 12/155,544. It is an aspect of one embodiment of the present subject matter to provide novel tooling, significantly thinner than conventional racks and tooling, without gears or bearings to house to thereby greatly reduce shadowing and improve coating uniformity.
• an exemplary sputtering system may include a substantially cylindrical, rotatable drum or carrier 2 having a plurality of pallets 50 mounted thereon.
• Each pallet 50 may comprise a rotatable central shaft 52 and one or more disks 11 axially aligned along the central shaft 52 whereby the disks 11 may provide a plurality of spindle carrying wells positioned about the periphery of the disk 11 and each spindle may carry one or more substrates adaptable to rotate about it respective axis.
• the substrate, drum and pallet may each possess their own respective rate of rotation. This effectively results in a lowering of the creation rate of type 2 absorbing oscillators at a given sputtering target power as the metal is deposited over a greater area. This also allows higher average coating rates before unacceptable absorption occurs.
• Embodiments of the present subject matter employed in an in line coating mechanism or sputtering system may be utilized to coat any number or type of substrate. Unlike drum type sputtering systems, an in line sputtering system generally does not require as many coating passes, rather, exemplary substrates may be coated in one long, continuous coating pass normally requiring a slow coating rate to ensure complete oxidation. Embodiments of the present subject matter may rotate the substrates at a rotational rate such that an area of the substrate exposed to the coating material moves to one side of the tooling before type 2 absorbing oscillators are formed thereby allowing the coating to be fully oxidized before the substrate rotates to another side of the tooling and receives additional coating material.
• the oxidation process may also be improved by the presence of a microwave driven plasma or an ion gun at one side of the tooling.
• Exemplary rotation speeds may result in less material being deposited per pass, but may allow sputtering targets on the in-line coater to be operated at a higher power thereby resulting in a faster average coating rate than would otherwise be possible.
• One embodiment of the present subject matter may also achieve higher sputtering system throughput by selecting the rotation direction of the substrate and/or planet to be the same as that of the drum.
• substrates rotating in one direction may exhibit an amount of absorption that differs from that shown by the substrates rotating in the other direction due to single pass non-uniformity.
• the nature of this non-uniformity may be such that it is not possible to have the same absorption (or lack thereof) in both sets of substrates while at the same time maximizing the average deposition rate.
• Exemplary tooling allowing all of the substrates lamps to rotate in the same direction may minimize the absorption for all of the substrates.
• rotating flats e.g., planar flats, triangular flats, and other suitably shaped flats.
• a method for forming thin films on substrates is provided using a coating system wherein a number of atoms of an element are deposited on an area of substrate surface during a coating cycle and reacted with another element to form a thin film at a first rate of formation.
• the method may include increasing the surface area of the substrate and the number of atoms of the element that are deposited on the substrate surface during a coating cycle at step 910.
• one or more process parameters may be adjusted to obtain a rate of formation of the thin film per unit area of substrate surface greater than the product of (i) the ratio of the area of the substrate surface having atoms deposited thereon during a coating cycle to the increased area, and (ii) the first rate of formation of the thin film.
• Exemplary parameters may include, but are not limited to, substrate rotation rate, substrate rotation direction, sputtering target width, number of sputtering targets, drum diameter, shape of a deposition pattern past a sputtering target, amplitude of a deposition pattern past a sputtering target, masking, phasing of substrate rotation, exposure of the substrate in an oxidation zone, tooling, and combinations thereof.
• FIG 10 is a block diagram of another embodiment of the present subject matter.
• a novel method of forming a non-absorbing thin film on a surface of a substrate is provided where, at step 1010, a sputtering target may be
• the substrate surface may be exposed to the target at a first exposure rate to effect the deposition of the sputtered target material on the surface of the substrate at a first deposition rate per unit of area of substrate surface.
• the rate of exposure of the substrate surface to the target may then be increased.
• the sputtering target may be operated, at step 1040, at a second sputtering rate of the target material so that the deposition rate of sputtered target material per unit of area of substrate surface is greater than the product of (i) the ratio of the first exposure rate of the substrate surface to the increased exposure rate of the substrate surface, and (ii) the first deposition rate per unit of area of substrate surface.
• the step of increasing the rate of exposure of the substrate surface to the target may include operating a second sputtering target at a second sputtering rate of target material and exposing the substrate surface to the second target at the first exposure rate to effect the deposition of the sputtered target material on the surface of the substrate at greater than the first deposition rate per unit of area of substrate surface.
• FIG. 11 is a block diagram of another embodiment of the present subject matter.
• a method of increasing the rate of formation of a substantially non-absorbing thin film on one or more substrates may include at step 1110, increasing the capacity of tooling for holding one or more substrates in an exemplary sputtering system to thereby increase the surface area of substrates held by the tooling.
• the area of the substrates exposed to a source of deposition material and a reactive atmosphere per unit of time may be increased.
• step 1110 may further include providing a plurality of pallets carried by a substrate carrier, each pallet comprising a rotatable central shaft
• step 1120 may further include adjusting one or more parameters such as, carrier rotation rate, planetary rotation rate, substrate rotation rate, planetary rotation direction, substrate rotation direction, target exposure phasing, reactive atmosphere exposure phasing, and combinations thereof.
• a reactive coating system may include a target material deposited and reacted on a substrate surface to form a substantially non-absorbing thin film.
• Figure 12 is a block diagram of one embodiment of the present subject matter.
• a method of increasing the volume of the non-absorbing thin film formed per unit of time may include at step 1210, increasing the area of the surface by a factor of "x" and at step 1220 increasing the rate of deposition of the target material by a factor greater than the inverse of the factor "x" to thereby increase the rate of formation of the volume of non-absorbing thin film per unit of time.

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