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
  • C23C14/34—Sputtering
  • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
• • 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
  • C23C14/35—Sputtering by application of a magnetic field, e.g. magnetron sputtering
• • 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
  • C23C14/56—Apparatus specially adapted for continuous coating; Arrangements for maintaining the vacuum, e.g. vacuum locks
  • C23C14/564—Means for minimising impurities in the coating chamber such as dust, moisture, residual gases
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering
  • H01J37/3402—Gas-filled discharge tubes operating with cathodic sputtering using supplementary magnetic fields
  • H01J37/3405—Magnetron sputtering
  • H01J37/3408—Planar magnetron sputtering
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering
  • H01J37/3411—Constructional aspects of the reactor
  • H01J37/3414—Targets
  • H01J37/3426—Material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering
  • H01J37/3411—Constructional aspects of the reactor
  • H01J37/3414—Targets
  • H01J37/3426—Material
  • H01J37/3429—Plural materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering
  • H01J37/3411—Constructional aspects of the reactor
  • H01J37/3435—Target holders (includes backing plates and endblocks)
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering
  • H01J37/3411—Constructional aspects of the reactor
  • H01J37/3441—Dark space shields
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
  • H10P14/22—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials using physical deposition, e.g. vacuum deposition or sputtering

Definitions

• the field of the subject matter is the design and use of DC magnetron sputtering systems, including targets, particle catch-rings and reduction of particle generation in these systems.
• Electronic and semiconductor components are used in ever-increasing numbers of consumer and commercial electronic products, communications products and data- exchange products. Examples of some of these consumer and commercial products are televisions, computers, cell phones, pagers, palm-type or handheld organizers, portable radios, car stereos, or remote controls. As the demand for these consumer and commercial electronics increases, there is also a demand for those same products to become smaller and more portable for the consumers and businesses. As a result of the size decrease in these products, the components that comprise the products must also become smaller and/or thinner. Examples of some of those components that need to be reduced in size or scaled down are microelectronic chip interconnections, semiconductor chip components, resistors, capacitors, printed circuit or wiring boards, wiring, keyboards, touch pads, and chip packaging.
• Electronic, semiconductor and communication/data-exchange components are composed, in some cases, of layers of materials, such as metals, metal alloys, ceramics, inorganic materials, polymers, or organometallic materials.
• the layers of materials are often thin (on the order of less than a few tens of angstroms in thickness).
• the process of forming the layer - such as physical vapor deposition of a metal or other compound - should be evaluated and, if possible, modified and improved.
• the surface and/or material composition must be measured, quantified and defects or imperfections detected.
• the deposition of a layer or layers of material its not the actual layer or layers of material that should be monitored but the material and surface of that material that is being used to produce the layer of material on a substrate or other surface.
• the atoms and molecules being deflected or liberated from the target must travel a path to the substrate or other surface that will allow for an even and uniform deposition.
• Atoms and molecules traveling natural and expected paths after deflection and/or liberation from the target can unevenly deposit on the surface or substrate, including trenches and holes in the surface or substrate.
• deposition begins with plasma ignition that is triggered by electrical arcing between an anodic shield and a cathodic target. Particles are always generated during arcing and become a major source of defects responsible for the reduced yield in microelectronic chip fabrication.
• the strike arc induced particles are ejected at a high velocity, like shot gun pellets, guided by the gap between the shield and the target side wall. These particles not only land on the wafer surface, but their impact also causes severe plowing and chipping on the wafer, predominately on the outer edges of the wafer's top surface, producing additional particles, particularly silicon and oxygen containing particles.
• the modified design includes: a) the design concept is not based on the physics of arcing, so the design optimization is not realized; b) the sloped target sidewall acts as reflective plane for the strike-arc induced particles, redirecting some of the particles toward the wafer; c) the target edge cools faster than the center due to the lower plasma density at the edge and the conductive medium underneath, so sputter atoms condense easily on the edge causing nodule formation; d) although a ledge is introduced by machining the backing plate, the positive slope results in inefficient strike-arc sites (i.e., less sharp, lower electric potential field); and e) the gradual change of the positive slope and somewhat shallow trench depth make a poorly defined demarcation between arcing and non-arcing area.
• Modified targets a) should be designed based on the physics of electric potential field, so the design optimization is realized, and in some cases the magnetic field; b) should have a modified target sidewall that does not merely act as reflective plane for the strike-arc induced particles redirecting some of the particles toward the wafer; c) should have a target edge that has a cooling pattern similar to the center, so sputter atoms do not condense easily on the edge causing nodule formation; d) any modification should result in efficient strike-arc sites (i.e., less sharp, lower electric potential field); and e) the modification should result in a defined demarcation between the arcing and non-arcing area.
• Field-enhanced sputtering targets include: a core material; and a surface material, wherein at least one of the core material or the surface material has a field strength design profile and wherein the sputtering target comprises a substantially uniform erosion profile.
• Target assembly systems include a field-enhanced sputtering target; and an anodic shield.
• methods of producing a substantially uniform erosion on a sputtering target include: providing an anodic shield; providing a cathodic field- enhanced target; and initiating a plasma ignition arc, whereby the arc is located at the point of least resistance between the anodic shield and the cathodic field-enhanced target.
• Prior Art Figure 1 shows a conventional cathode target 100/anodic shield 110 arrangement.
• Figure 3 shows the effect of an insulating layer buildup on non-eroding "race tracks”.
• Figure 4 shows a conventional target design as compared to a contemplated target design.
• Figure 5 shows a conventional target design as compared to a contemplated target design.
• Figure 6 shows a conventional target design as compared to a contemplated target design.
• Figure 7 shows a conventional target design as compared to a contemplated target design.
• Figure 8 shows the electric field concept for both a hemisphere and a circle.
• Figure 9 shows an erosion profile 920 of a typical target 910.
• Figure 10 shows an anticipated erosion profile 1020 of a field-enhanced titanium target 1000, where both the eroding and low-eroding peaks are kept to the same level of the original surface.
• Figure 11 shows a comparison of a conventional aluminum target 1100 with a field- enhanced aluminum target 1 140 wherein the erosion profile 1110 of the conventional target 1 100 is shown on the field enhanced target 1140 as compared with the field enhanced target surface 1130.
• Figure 12 shows another field enhanced surface design 1230 of the same target 1240, where the erosion profile 1210 is shown for reference.
• Figure 13 shows erosion profiles versus target life for 35 ⁇ m grain aluminum target.
• Figure 14 shows the conventional system from Prior Art Figure 1 where a particle catch- ring is coupled to and located around the anodic shield.
• Figures 15A-15D show the impact of strike-arc-induces particles with a TiN target.
• Figure 16A shows the results of a plasma that is initiated via arcing that inevitably produces particles 1610 on a wafer 1600.
• Figure 16B shows how strike-arc induced particles 1610 near the wafer edge 1620 are arrested by incorporating a catch-ring system.
• Figure 17 shows a spark-ring target design 1710 concept for particle reduction - showing both the conventional design 1700 and a contemplated design 1710.
• Figure 18 shows a typical erosion profile 1820 for a standard target before 1800 and after 80O kWh 1810.
• a standard magnet 1910, which is designed to optimize film uniformity, is shown in Figure 19.
• Figure 20 shows a new conventional or standard target 2000 and the design of a new field-enhanced target 2010.
• Figure 21 shows the surface contours/erosion profiles of a conventional or standard target 2100 and a field-enhanced target after 800 kWh 2110.
• Figures 22A and 22B show I-V variation versus target life for a standard target and a field- enhanced target.
• Figures 23A and 23B show deposition rate versus power at various target lives for a standard target and a field-enhanced target.
• Figures 24A and 24B show the erosion profile versus life of both a standard target and a field-enhanced target at 800 kWh.
• Figure 25 shows a comparison of the erosion profile at 800 kWh of the standard and field- enhanced targets.
• Figure 26 shows a comparison of the erosion thickness at 800 kWh of the standard and field-enhanced targets.
• Figure 27 shows the erosion thickness of a field-enhanced aluminum target at 400 kWh and 800 kWh.
• Table 1 shows material distribution after 800 kWh.
• Prior Art Figure 1 shows a conventional cathode target 100/anodic shield 1 10 arrangement. The target and anode are connected to a DC power supply 105. In this conventional arrangement comprising two magnetic poles 115, a dense plasma 130 is formed around a magnetic field orflux 120. The strike area 140 is also shown. Water 175 is directed into the system with the help of a rotary motor 190. In this embodiment, a silicon wafer 150 is placed in the chamber 180 on top of a heated gas line 170. Process gas 160 is added to the chamber and pumped out by pump 165.
• Particles are always generated during arcing and become a major source of defects responsible for the reduced yield in microelectronic chip fabrication.
• the strike arc induced particles and/or plasma ignition particles are ejected at a high velocity, like shot gun pellets, guided by the gap between the shield and the target side wall. These particles not only land on the wafer surface, but their impact also causes severe plowing and chipping on the wafer, predominately on the outer edges of the wafer's top surface, producing additional particles, particularly silicon and oxygen containing particles. Some of the small airborne particles stick to the target and surrounding surfaces becoming additional arc sites, further negatively impacting yield management. In addition, conventional target surfaces regularly erode in a non-uniform manner during use, which can lead to inferior deposition layers.
• Modified targets described herein a) are designed based on the physics of electric potential field, so the design optimization is realized, and in some cases take into effect the magnetic field effect; b) have a modified target sidewall that does not merely act as reflective plane for the strike-arc induced particles redirecting some of the particles toward the wafer; c) have a target edge that has a cooling pattern similar to the center, so sputter atoms do not condense easily on the edge causing nodule formation; d) result in efficient strike-arc sites (i.e., less sharp, lower electric potential field); and e) result in a defined demarcation between the arcing and non- arcing area.
• the erosion profile of a target is mainly determined by the magnet configuration in a DC magnetron sputtering system.
• the magnets also affect the I- V characteristics, deposition rate, film uniformity, and target life.
• the electric field on the target surface, and in some embodiments the magnetic field is used as an additional control parameter to improve target performance.
• this parameter is a very powerful tool in controlling the target performance. The results show that the erosion profile of a target and the film uniformity can be controlled in a desired way by tailoring the surface contour or electric field of a target.
• Field-enhanced sputtering targets include: a core material; and a surface material, wherein at least one of the core material or the surface material has a field strength design profile and wherein the sputtering target comprises a substantially uniform erosion profile.
• Target assembly systems are also disclosed that include a field- enhanced sputtering target; and an anodic shield. Additionally, methods of producing a substantially uniform erosion on a sputtering target are described that include: providing an anodic shield; providing a cathodic field-enhanced target; and initiating a plasma ignition arc, whereby the arc is located at the point of least resistance between the anodic shield and the cathodic field-enhanced target.
• field strength design profile means strategic target modifications designed to take into account the field strength effects during use, such as the electric field strength effects, the magnetic field strength effects for a combination thereof.
• a "uniform erosion profile” means that contemplated sputtering targets erode during use in a uniform manner based on the strategic target modifications mentioned herein.
• the target designs disclosed herein enhance the electric field strength of the poorly eroding race tracks on a target surface, such as those shown in Figure 2, by tailoring the surface geometry, such that it enhances sputtering efficiency around the edge and on the poorly eroding race tracks, prevents a buildup of insulating layer (which are tantamount to large dielectric particles) and nodules formation, extends the target life, and improves the film uniformity.
• an erosion profile 210 is shown, along with an actual eroded conventional target 220.
• On this target 220 there are eroding tracks 230, non-eroding or poorly eroding tracks 240 and a nodule and insulating layer 250 that forms on the non- eroding edge track 260. So, for example, during a TTN process, poorly conducting nitride films build up along the poorly eroding "race tracks" or "tracks", on which charges accumulate resulting in increased field strength and arcing, particularly at a later stage in target life.
• Figure 3 shows the effect of an insulating layer buildup on non-eroding "race tracks".
• the particle count was found to increase linearly with target usage.
• the particle count increased continuously, suggesting that the origin of the particles was the target - not the shield.
• particles were found to be circularly distributed around the edge of the wafers, suggesting that the build up of the insulating layer on the non-eroding race track and possibly the condensation around the target sidewall are likely the cause of the particles.
• Contemplated design modifications are based on the principle that the electric field strength is stronger on the area with a curvature and/or sharp curvature than the surrounding flat area and that the plasma attraction increases with increasing electric field strength.
• the most significant problem areas are the edge and non-eroding race tracks of a target where the plasma density and the erosion rate are low.
• the target edge and the poorly eroding race tracks are made to have a more pronounced or sharper curvature than the neighboring area, such that the electric field strength and plasma density are enhanced on such areas, resulting in reduced particle generation, extended target life, and improved film uniformity.
• Figures 4-7 show several contemplated designs where the original target (410, 510, 610 and 710, respectively) design has been modified according to the stated principles to produce a modified target (420, 520, 620, 720, respectively).
• Some contemplated benefits of the novel designs include: a) sharper (but tapered), recessed (1 ⁇ 2 mm), and raised tip (430, 530, 630 and 730, respectively), including a sharper, more pronounced tip, whereby a higher electric field attracts more plasma (more sputtering) and thus prevents nodule condensation, a recessed position - wider spacing from the shield prevents strike-arc here; b) a recessed sidewall groove (440, 540, 640 and 740, respectively), as much as allowed, wherein a recessed groove slows cooling (less condensation), traps arc-induced particles, and holds condensation nodules (possibly with nitride B-blast), and a recessed groove prevents arcing here and thus reduces the knock-
• the field strength design profile which incorporates the benefits described above, comprises at least one curvature feature.
• contemplated targets comprise at least one curvature feature on the target edge.
• conventional targets comprise at least one high erosion area that presents itself during use.
• at least one curvature feature is applied to the at least one high erosion area prior to the initial use of the sputtering target.
• the at least one curvature feature comprises strategic target surface modification based on a contemplated and known erosion profile that develops during use.
• modified targets will comprise less core and surface material than standard or conventional targets. In some contemplated embodiments, modified targets comprise at least about 5% less core and surface material than standard or conventional targets. In other contemplated embodiments, modified targets comprise at least about 10% less core and surface material than standard or conventional targets. In yet other contemplated embodiments, modified targets comprise at least about 15% less core and surface material than standard or conventional targets. To understand the theory behind these contemplated design modifications and their success one should review the calculation of the electric field for both a hemisphere and a circle.
• Figure 9 shows an erosion profile 920 of a typical target 910.
• Figure 10 shows an anticipated erosion profile 1020 of a field-enhanced titanium target 1000, where both the eroding and low-eroding peaks are kept to the same level of the original surface.
• the eroding peaks are maintained to the original surface level 1010 to keep the maximum material available to be sputtered, as shown by the field-enhanced target surface 1030.
• the low-eroding peaks are also placed to the same level of the original surface to increase the electric field, thereby enhancing plasma attraction and sputtering.
• Figure 11 shows a comparison of a conventional aluminum target 1100 with a field- enhanced aluminum target 1 140 wherein the erosion profile 1110 of the conventional target 1 100 is shown on the field enhanced target 1140 as compared with the field enhanced target surface 1 130.
• the peak surface height is kept at the same level as the original target surface 1120 or can be enhanced if extended target life is desired.
• Figure 12 shows another field enhanced surface design 1230 of the same target
• FIG. 1240 where the erosion profile 1210 and original target surface 1220 are shown for reference.
• Figure 13 shows erosion profiles versus target life for 35 ⁇ m grain aluminum target.
• the erosion rate increases initially with increasing curvature, but slows down as the re-deposition effect becomes larger in the steep groove.
• the enhancement of erosion rate is apparent with increasing curvature (target lift) for both the hills and the valleys.
• the electric field on the target surface is used as an additional control parameter to improve plasma distribution and erosion profile.
• the "Field Enhanced" target the first peaks are made at fast and poorly eroding areas, to have more materials on the fast eroding areas and to enhance electric field on the poorly eroding areas.
• a DC magnetron sputtering system comprises an anodic shield; a cathodic target that comprises at least one sidewall; a plasma ignition arc; and a catch-ring coupled to and located around the shield.
• Figure 14 shows the conventional system from Prior Art Figure 1 where a particle catch-ring is coupled to and located around the anodic shield.
• the modified system in Figure 14 shows a cathode target 1400/anodic shield 1410 arrangement.
• the target and anode are connected to a DC power supply (not shown).
• a catch ring or coil 1445 and a strike arc region 1447 is coupled to and located around the anode 1410 in order to help control errant particles 1460 and additional deposit buildup 1465.
• water is directed into the system with the help of a rotary motor.
• a silicon wafer 1450 is placed in the chamber 1480 on top of a heated gas line (not shown). Process gas is added to the chamber and pumped out by pump.
• Figures 15A-15D show the impact of strike-arc-induces particles with a TiN target.
• Figure 16A shows the results of a plasma that is initiated via arcing that inevitably produces particles 1610 on a wafer 1600.
• the strike-arc induced particles 1610 are mostly confined within a few mm of the wafer perimeter 1620 because the particle ejection projectile is guided by the approximately 1 mm gap between the anodic shield and the cathodic target-sidewall. These particles 1610 become subsequent arcing sites that contaminate the target and cause defects in the wafers.
• particles can be arrested before reaching the wafer by placing a catch-ring around the shield in the particle projectile path. A particle catch-ring is coupled to and is placed around the anodic shield below the target.
• the position and placement of the ring is determined by the need to block the ejected particles but not to interfere the sputtered atoms.
• the width of a catch-ring is designed to allow about 1 -3 mm overlap with the projection of the target's edge.
• the width of the ring can be increased as the ring is lowered away from the target.
• Typical ring width can be about 1 cm at about 2 cm below the target.
• Such an arrangement also extends the anodic field, so the plasma density near the edge of the target can be increased, resulting in reduced nodule formation around the edge of the target, particularly in nitriding process such as TaN and TiN.
• Figure 16B shows how strike-arc induced particles 1610 near the wafer edge 1620 are arrested by incorporating a catch-ring system.
• the particles shown on the wafer 1600 in this figure are mostly from a flaking shield that had reached a maintenance cycle. If the chamber had been clean, there would have been much fewer particles.
• the initial arc is located so as to direct the particles to areas that will minimize their damage to the microelectronic devices on the wafer.
• a DC magnetron sputtering system comprises an anodic shield; a cathodic target comprising at least one recess, cavity or a combination thereof and at least one protrusion; and a plasma ignition arc, whereby the arc is located at the point of least resistance between the anodic shield and the at least one recess, cavity or a combination thereof, the at least one protrusion or a combination thereof.
• the relocation of the arcing sites keeps the arc induced particle projectiles from reaching the surface of a wafer or the target surface in the sputtering system.
• Trench recesses can be modified and deepened such that strike-arc induced particle projectiles are not in line-of-sight with the wafer.
• arc induced particle projectiles are directed away from the wafer surface by locating the initial arc site inside the recess or cavity or by locating the initial arc site where the protrusion has been formed.
• protrusions may also be located or formed on the anodic shield in order to correspond with a protrusion or formation on or in the cathodic target having a vent slot.
• the system comprises an anodic shield comprising at least one protrusion; a cathodic target comprising at least one recess, cavity or a combination thereof; and a plasma ignition arc, whereby the arc is located at the point of least resistance between the at least one protrusion coupled to the anodic shield and the at least one protrusion, recess or cavity.
• the plasma ignition arc will occur at the point of least resistance, typically the closest distance between the cathode (target) and anode (chamber shield) surfaces. This concept is similar to a spark plug in that it uses a electrical protrusion, or pin, as a point of highest electric potential field to start the plasma arc in a specific location.
• the ejected projectiles can be directed away from the wafer surface.
• a simple pin can be located high on the side of the target sidewall such that projectiles are directed through a very narrow path that reduces the line of sight to the wafer.
• a recess can be made in the target and corresponding pins
• An ignition enclosure can be made, that uses target supply voltages in an enclosure which shields particles, and the ignition enclosure can be placed in the chamber. Another method is to use the target supply (or external voltage) to ignite an arc in a recess built into the target that will direct arc projectiles in a desired path away from the wafer or target surface.
• the arc induced particle projectiles can be significantly reduced when compared to a conventional system, wherein the cathodic target and/or the anodic shield are not modified by including a catch ring system or a protrusion, recess, cavity or combination thereof.
• the conventional system such as that shown in Prior Art Figure 1 , can be considered the "reference" or "control” meaning that the number of arc-induced particle projectiles produced in conventional systems should be the zero point by which all other modified systems are measured.
• the number of arc-induced particle projectiles are reduced by at least about 10%.
• the number of arc-induced particle projectiles are reduced by at least about 25%.
• the number of arc-induced particle projectiles are reduced by at least about 50%.
• Figure 17 shows a spark-ring target design 1710 concept for particle reduction - showing both the conventional design 1700 and the new design 1710.
• the design concept is based on the physics of arcing, in which the contemplated arcing sites 1720 and 1725, respectively, are narrow gaps and the sites with sharp asperities.
• a spark-ring 1730 is placed away from the target sidewall and the arc-induced particles are arrested in the grooved sidewall 1750 and on top of the shield 1740.
• Methods are also provided whereby the gas turbulence effect is mitigated, such methods include providing an anodic shield; providing a cathodic target comprising at least one recess, cavity or a combination thereof and at least one protrusion; and initiating a plasma ignition arc, whereby the arc is located at the point of least resistance between the anodic shield and the at least one recess, cavity or a combination thereof, the at least one protrusion or a combination thereof. Additional methods include providing an anodic shield; providing a cathodic target that comprises at least one sidewall; providing a catch-ring coupled to and around the shield; and initiating a plasma ignition arc.
• Methods are also provided whereby the gas turbulence effect is mitigated, such methods include providing an anodic shield comprising at least one protrusion; providing a cathodic target comprising at least one recess, cavity or a combination thereof; and initiating a plasma ignition arc, whereby the arc is located at the point of least resistance between the at least one protrusion coupled to the anodic shield and the at least one protrusion, recess or cavity.
• Contemplated coil sets may include those described in US Application Serial No.: 11/086022 filed on March 22, 2005, which is commonly-owned and incorporated herein in its entirety by reference.
• Sputtering targets contemplated herein also comprise a surface material and a core material, wherein the surface material is coupled to the core material.
• the surface material is that portion of the target that is exposed to the energy source at any measurable point in time and is also that part of the overall target material that is intended to produce atoms that are desirable as a surface coating.
• the term "coupled” means a physical attachment of two parts of matter or components (adhesive, attachment interfacing material) or a physical and/or chemical attraction between two parts of matter or components, including bond forces such as covalent and ionic bonding, and non-bond forces such as Van der Waals, electrostatic, coulombic, hydrogen bonding and/or magnetic attraction.
• the surface material and core material may generally comprise the same elemental makeup or chemical composition/component, or the elemental makeup and chemical composition of the surface material may be altered or modified to be different than that of the core material.
• the surface material and the core material comprise the same elemental makeup and chemical composition.
• the surface material and the core material may be tailored to comprise a different elemental makeup or chemical composition.
• the core material is designed to provide support for the surface material and to possibly provide additional atoms in a sputtering process or information as to when a target's useful life has ended.
• the core material comprises a material different from that of the original surface material, and a quality control device detects the presence of core material atoms in the space between the target and the wafer, the target may need to be removed and retooled or discarded altogether because the chemical integrity and elemental purity of the metal coating could be compromised by depositing undesirable materials on the existing surface/wafer layer.
• the core material is also that portion of a sputtering target that does not comprise macroscale modifications or microdimples, such as those disclosed in PCT Application Serial No.:
• the core material is generally uniform in structure and shape.
• the surface material is that portion of the target that is exposed to the energy source at any measurable point in time and is also that part of the overall target material that is intended to produce atoms and/or molecules that are desirable as a surface coating.
• Contemplated surface materials make up a portion of the core material, which is the material of the target.
• Sputtering targets, catch-rings and/or other related particle generation apparatus may generally comprise any material that can be a) reliably formed into a sputtering target, catch-rings and/or other related particle generation apparatus; b) sputtered from the target (and sometimes the coil) when bombarded by an energy source; and c) suitable for forming a final or precursor layer on a wafer or surface.
• the catch-ring comprises materials that are considered the same or similar to those materials being sputtered, the catch-ring may or may not sputter atoms. Coil sputtering depends primarily on the coil bias with respect to the plasma and the wafer.
• metals Materials that are contemplated to make suitable sputtering targets, catch-rings and/or other related particle generation apparatus are metals, metal alloys, conductive polymers, conductive composite materials, conductive monomers, dielectric materials, hardmask materials and any other suitable sputtering material.
• metal means those elements that are in the d-block and f-block of the Periodic Chart of the Elements, along with those elements that have metal-like properties, such as silicon and germanium.
• d-block means those elements that have electrons filling the 3d, 4d, 5d, and 6d orbitals surrounding the nucleus of the element.
• f-block means those elements that have electrons filling the 4f and 5f orbitals surrounding the nucleus of the element, including the lanthanides and the actinides.
• Preferred metals include titanium, silicon, cobalt, copper, nickel, iron, zinc, vanadium, ruthenium, zirconium, aluminum and aluminum-based materials, tantalum, niobium, tin, chromium, platinum, palladium, gold, silver, tungsten, molybdenum, cerium, promethium, thorium or a combination thereof.
• More preferred metals include copper, aluminum, ruthenium, tungsten, titanium, cobalt, tantalum, magnesium, lithium, silicon, manganese, iron or a combination thereof. Most preferred metals include copper, aluminum and aluminum- based materials, tungsten, titanium, zirconium, cobalt, ruthenium, tantalum, niobium or a combination thereof.
• contemplated and preferred materials include aluminum and copper for superfine grained aluminum and copper sputtering targets; aluminum, copper, cobalt, tantalum, zirconium, and titanium for use in 200 mm and 300 mm sputtering targets, along with other mm-sized targets; and aluminum for use in aluminum sputtering targets that deposit a thin, high conformal "seed" layer of aluminum onto surface layers.
• the phrase "and combinations thereof" is herein used to mean that there may be metal impurities in some of the sputtering targets, such as a copper sputtering target with chromium and aluminum impurities, or there may be an intentional combination of metals and other materials that make up the sputtering target, such as those targets comprising alloys, borides, carbides, fluorides, nitrides, suicides, oxides and others.
• Materials contemplated herein also comprise those materials described in commonly-owned PCT Application Serial No.: PCT/US05/13663 entitled “Novel Ruthenium Alloys, Their Use in Vapor Deposition or Atomic Layer Deposition and Films Produced Therefrom", which was filed on April 21 , 2005 and which is incorporated herein in its entirety by reference.
• metal also includes alloys, metal/metal composites, metal ceramic composites, metal polymer composites, as well as other metal composites. Alloys contemplated herein comprise gold, antimony, arsenic, boron, copper, germanium, nickel, indium, palladium, phosphorus, silicon, cobalt, vanadium, iron, hafnium, titanium, iridium, zirconium, tungsten, silver, platinum, tantalum, tin, zinc, lithium, manganese, rhenium, and/or rhodium.
• Specific alloys include gold antimony, gold arsenic, gold boron, gold copper, gold germanium, gold nickel, gold nickel indium, gold palladium, gold phosphorus, gold silicon, gold silver platinum, gold tantalum, gold tin, gold zinc, palladium lithium, palladium manganese, palladium nickel, platinum palladium, palladium rhenium, platinum rhodium, silver arsenic, silver copper, silver gallium, silver gold, silver palladium, silver titanium, titanium zirconium, aluminum copper, aluminum silicon, aluminum silicon copper, aluminum titanium, chromium copper, chromium manganese palladium, chromium manganese platinum, chromium molybdenum, chromium ruthenium, cobalt platinum, cobalt zirconium niobium, cobalt zirconium rhodium, cobalt zirconium tantalum, copper nickel, iron aluminum, iron rhodium, iron tantalum, chromium silicon
• chromium boride lanthanum boride, molybdenum boride, niobium boride, tantalum boride, titanium boride, tungsten boride, vanadium boride, zirconium boride, boron carbide, chromium carbide, molybdenum carbide, niobium carbide, silicon carbide, tantalum carbide, titanium carbide, tungsten carbide, vanadium carbide, zirconium carbide, aluminum fluoride, barium fluoride, calcium fluoride, cerium fluoride, cryolite, lithium fluoride, magnesium fluoride, potassium fluoride, rare earth fluorides, sodium fluoride, aluminum nitride,
• Thin layers or films produced by the sputtering of atoms or molecules from targets discussed herein can be formed on any number or consistency of layers, including other metal layers, substrate layers, dielectric layers, hardmask or etchstop layers, photolithographic layers, anti-reflective layers, etc.
• the dielectric layer may comprise dielectric materials contemplated, produced or disclosed by Honeywell International, Inc.
• FLARE polyarylene ether
• adamantane-based materials such as those shown in pending application 09/545058 ; Serial PCT/US01/22204 filed October 17, 2001 ; PCT/US01/50182 filed December 31 , 2001 ; 60/345374 filed December 31 , 2001 ; 60/347195 filed January 8, 2002; and 60/350187 filed January 15, 2002;
• the wafer or substrate may comprise any desirable substantially solid material. Particularly desirable substrates would comprise glass, ceramic, plastic, metal or coated metal, or composite material.
• the substrate comprises a silicon or germanium arsenide die or wafer surface, a packaging surface such as found in a copper, silver, nickel or gold plated leadframe, a copper surface such as found in a circuit board or package interconnect trace, a via-wall or stiffener interface ("copper” includes considerations of bare copper and its oxides), a polymer-based packaging or board interface such as found in a polyimide-based flex package, lead or other metal alloy solder ball surface, glass and polymers such as polyimides.
• the substrate comprises a material common in the packaging and circuit board industries such as silicon, copper, glass, or a polymer.
• the substrate layer may also comprise a plurality of voids if it is desirable for the material to be nanoporous instead of continuous.
• Voids are typically spherical, but may alternatively or additionally have any suitable shape, including tubular, lamellar, discoidal, or other shapes. It is also contemplated that voids may have any appropriate diameter. It is further contemplated that at least some of the voids may connect with adjacent voids to create a structure with a significant amount of connected or "open" porosity.
• the voids preferably have a mean diameter of less than 1 micrometer, and more preferably have a mean diameter of less than 100 nanometers, and still more preferably have a mean diameter of less than 10 nanometers. It is further contemplated that the voids may be uniformly or randomly dispersed within the substrate layer. In a preferred embodiment, the voids are uniformly dispersed within the substrate layer.
• the surface provided is contemplated to be any suitable surface, as discussed herein, including a wafer, substrate, dielectric material, hardmask layer, other metal, metal alloy or metal composite layer, antireflective layer or any other suitable layered material.
• the coating, layer or film that is produced on the surface may also be any suitable or desirable thickness - ranging from one atom or molecule thick (less than 1 nanometer) to millimeters in thickness.
• Wafers and layered materials (stacks) produced from the sputtering systems described herein can be incorporated into any process or production design that produces, builds or otherwise modifies electronic, semiconductor and communication/data transfer components.
• Electronic, semiconductor and communication components as contemplated herein are generally thought to comprise any layered component that can be utilized in an electronic-based, semiconductor-based or communication-based product.
• Contemplated components comprise micro chips, circuit boards, chip packaging, separator sheets, dielectric components of circuit boards, printed-wiring boards, touch pads, wave guides, fiber optic and photon-transport and acoustic-wave-transport components, any materials made using or incorporating a dual damascene process, and other components of circuit boards, such as capacitors, inductors, and resistors.
• Electronic-based, semiconductor-based and communications-based/data transfer- based products can be "finished” in the sense that they are ready to be used in industry or by other consumers. Examples of finished consumer products are a television, a computer, a cell phone, a pager, a palm-type organizer, a portable radio, a car stereo, and a remote control. Also contemplated are "intermediate" products such as circuit boards, chip packaging, and keyboards that are potentially utilized in finished products. Electronic, semiconductor and communication/data transfer products may also comprise a prototype component, at any stage of development from conceptual model to final scale-up mock-up. A prototype may or may not contain all of the actual components intended in a finished product, and a prototype may have some components that are constructed out of composite material in order to negate their initial effects on other components while being initially tested.
• Figure 18 shows a typical erosion profile 1820 for a standard target before 1800 and after 800 kWh 1810.
• the erosion profile of the standard target is dictated by the configuration of the magnets behind the target.
• a standard magnet 1910 which is designed to optimize film uniformity, is shown in Figure 19.
• these fixed magnets have a limited capacity in controlling plasma distribution.
• Figure 20 shows a new conventional or standard target 2000 and the design of a new field-enhanced target 2010. Not only is the field-enhanced target better for these types of applications, as will be shown by the data, but they also use, in some embodiments, about 15% less material than the standard target, as shown by the weight in grams.
• Figure 21 shows the surface contours/erosion profiles of a conventional or standard target 2100 and a field-enhanced target after 800 kWh 2110.
• the standard target shows preferential erosion where the magnetic field is stronger, whereas the field- enhanced target shows uniform erosion, because both magnetic and electric field strength control the erosion.
• Figures 22A and 22B show I-V variation versus target life for a standard target and a field-enhanced target.
• the results for a standard target, shown in Figure 22A shows an increasing shift in I-V curves as the target erodes. The surface are of the target increases as erosion grooves develop. The increased area (current path) allows higher current flow resulting in reduced operating voltage.
• the results for a field-enhanced target, shown in Figure 22B delivers almost invariant I-V performance with target erosion.
• the overall operating voltage is slightly higher than that of the standard target because of the enhanced field strength by pre-grooving, which increases the operating voltage. Pre- grooving makes the target surface area change slowly with target erosion, resulting in almost invariant I-V characteristics.
• Figures 23 A and 23B show deposition rate versus power at various target lives for a standard target and a field-enhanced target.
• the standard target shows a decreasing trend of deposition rate with target erosion, mainly because of the increasing fraction of re- deposition in the deepening erosion grooves.
• the field-enhanced target shows very little change in deposition rate with target erosion. It is possible that the field-enhanced target may not require power or time compensation with target erosion.
• Figures 24A and 24B show the erosion profile versus life of both a standard target and a field-enhanced target at 800 kWh.
• the field-enhanced target showed 33% more materials left at the peak erosion area than the standard target.
• Figure 25 shows a comparison of the erosion profile at 800 kWh of the standard and field-enhanced targets.
• the field-enhanced target shows 2.9 mm (31 %) less erosion after 800 kWh than the standard target.
• Figure 26 shows a comparison of the erosion thickness at 800 kWh of the standard and field-enhanced targets.
• the field-enhanced target erodes more uniformly than the standard target and therefore extends the target life.
• the field-enhanced target can control both the erosion profile and the film uniformity.
• Figure 27 shows the erosion thickness of a field-enhanced aluminum target at 400 kWh and 800 kWh.
• the circled area in the graph shows clear evidence for erosion near the edge area of the target, suggesting that nodule formation can be suppressed by enhancing the electric-field strength at the edge area.
• Table 1 shows material distribution after 800 kWh. Both the standard and the field-enhanced targets show similar efficiency in material usage, but the field-enhanced target deposited 6% more material and left 30% more material in thickness because of uniform erosion, resulting in extended target life. Based on this data, 1000 kWh and 1200 kWh can be achieved without increasing overall target thickness to optimize kit change cycle.
• the field-enhanced targets show less variation in I-V curve and deposition rate with target life
• recalibration of the deposition parameter e.g. power or time compensation
• the electric field of a target surface and thus the erosion profile can be controlled via target surface contour without modifying the system configuration
• the erosion profile is determined by the existing system magnets and the electric field strength at the target surface, the latter being controlled by the target manufacturer
• film uniformity can be controlled via target surface contour.

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• 2009
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