Non-contact process kit

A process kit for use in a physical vapor deposition (PVD) chamber, along with a PVD chamber having a non-contact process kit are provided. In one embodiment, a process kit includes a generally cylindrical shield that has a substantially flat cylindrical body, at least one elongated cylindrical ring extending downward from the body, and a mounting portion extending upwards from an upper surface of the body. In another embodiment, a process kit includes a generally cylindrical deposition ring. The deposition ring includes a substantially flat cylindrical body, at least one downwardly extending u-channel coupled to an outer portion of the body, an inner wall extending upward from an upper surface of an inner region of the body, and a substrate support ledge extending radially inward from the inner wall.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the invention generally relate to a process kit for a semiconductor processing chamber, and a semiconductor processing chamber having a process kit. More specifically, the invention relates to a process kit that includes a ring and shield suitable for use in a physical vapor deposition chamber.

2. Description of the Related Art

Physical vapor deposition (PVD), or sputtering, is one of the most commonly used processes in the fabrication of electronic devices. PVD is a plasma process performed in a vacuum chamber where a negatively biased target is exposed to a plasma of an inert gas having relatively heavy atoms (e.g., argon (Ar)) or a gas mixture comprising such inert gas. Bombardment of the target by ions of the inert gas results in ejection of atoms of the target material. The ejected atoms accumulate as a deposited film on a substrate placed on a substrate support pedestal disposed within the chamber.

A process kit may be disposed in the chamber to help define a processing region in a desired region within the chamber with respect to the substrate. The process kit typically includes a cover ring, a deposition ring and a ground shield. Confining the plasma and the ejected atoms to the processing region helps maintain other components in the chamber free from deposited materials and promotes more efficient use of target materials, as a higher percentage of the ejected atoms are deposited on the substrate. The deposition ring additionally prevents deposition on the perimeter of the substrate support pedestal. The cover ring is generally used to create a labyrinth gap between the deposition ring and ground shield, thereby preventing deposition below the substrate. The cover ring also may be utilized to assist in controlling deposition at or below the substrate's edge.

Although conventional ring and shield designs have a robust processing history, the reduction in critical dimensions brings increasing attention to contamination sources within the chamber. As the rings and shield periodically contact each other as the substrate support pedestal raises and lowers between transfer and process positions, conventional designs are potential source of particulate contamination.

Moreover, since conventional cover ring designs are generally unconnected to temperature control sources, such as a chamber wall or substrate support pedestal, the temperature of the cover ring may fluctuate during the process cycle. The heating and cooling of the cover ring increases the stress in materials deposited on the cover ring, making the stressed material prone to flaking and particle generation. Thus, the inventors have realized that is would be advantageous to have a process kit that contributed to minimizing chamber contamination.

Therefore, there is a need in the art for an improved process kit.

SUMMARY OF THE INVENTION

The invention generally provides a process kit for use in a physical vapor deposition (PVD) chamber, and a PVD chamber having an interleaving process kit. In one embodiment, a process kit includes an interleaving deposition ring and ground shield. The deposition ring is configured to have a large pedestal contact surface and a plurality of substrate supporting buttons. When installed in a PVD chamber, the interleaving deposition ring and ground shield advantageously are maintained in contact with the substrate support pedestal and chamber walls, thereby promoting excellent and predictable temperature control that substantially minimize process contamination from films deposited thereon. Moreover, the interleaving deposition ring and ground shield advantageously are configured not come into contact during use within the PVD chamber, thereby eliminating a potential source of particle generation present in conventional designs.

In one embodiment, a process kit of the invention includes a generally cylindrical shield that has a substantially flat cylindrical body, at least one elongated cylindrical ring extending downward from the body, and a mounting portion extending upwards from an upper surface of the body.

In another embodiment, a process kit includes a generally cylindrical deposition ring. The deposition ring includes a substantially flat cylindrical body, at least one downwardly extending u-channel coupled to an outer portion of the body, an inner wall extending upward from an upper surface of an inner region of the body, and a substrate support ledge extending radially inward from the inner wall.

In yet another embodiment, a PVD chamber is provided that includes an interleaving ground shield and deposition ring configured not to touch during use of the PVD chamber.

DETAILED DESCRIPTION

The invention generally provides a process kit for use in a physical vapor deposition (PVD) chamber. The process kit advantageously has reduced potential for generating particulate contamination, which promotes greater process uniformity and repeatability along with longer chamber component service life.

FIG. 1depicts an exemplary semiconductor processing chamber150having one embodiment of a process kit114. The process kit114includes an interleaving deposition ring102and ground shield162. One example of a processing chamber that may be adapted to benefit from the invention is an IMP VECTRA™ PVD processing chamber, available from Applied Materials, Inc., of Santa Clara, Calif. It is contemplated that other processing chambers, including those from other manufacturers, may be adapted to benefit from the invention.

The exemplary processing chamber150includes a chamber body152having a bottom154, lid assembly156and sidewalls158that define an evacuable interior volume160. The chamber body150is typically fabricated from welded plates of stainless steel or a unitary block of aluminum. The sidewalls158generally contain a sealable access port (not shown) to provide for entry and egress of a substrate104from the processing chamber150. A pumping port122disposed in the sidewalls158is coupled to a pumping system120that exhausts and controls the pressure of the interior volume160. The lid assembly156of the chamber150generally supports the annular shield162that interleaves with the deposition ring102to confine a plasma formed in the interior volume160to the region above the substrate104.

A pedestal assembly100is supported from the bottom154of the chamber150. The pedestal assembly100supports the deposition ring102along with the substrate104during processing. The pedestal assembly100is coupled to the bottom154of the chamber150by a lift mechanism118that is configured to move the pedestal assembly100between an upper (as shown) and lower position. In the upper position, the deposition ring102is interleaved with the shield162in a spaced apart relation. In the lower position, the deposition ring102is disengaged from the shield162to allow the substrate104to be removed from the chamber150between the ring102and shield162through the access port disposed in the sidewall158. Additionally, in the lower position, lift pins (shown inFIG. 2) are moved through the pedestal assembly100to space the substrate104from the pedestal assembly100to facilitate exchange of the substrate104with a wafer transfer mechanism disposed exterior to the processing chamber150, such as a single blade robot (not shown). A bellows186is typically disposed between the pedestal assembly100and the chamber bottom154to isolate the interior volume160of the chamber body152from the interior of the pedestal assembly100and the exterior of the chamber.

The pedestal assembly100generally includes a substrate support140sealingly coupled to a platform housing108. The platform housing108is typically fabricated from a metallic material such as stainless steel or aluminum. A cooling plate124is generally disposed within the platform housing108to thermally regulate the substrate support140. One pedestal assembly100that may be adapted to benefit from the invention is described in U.S. Pat. No. 5,507,499, issued Apr. 16, 1996 to Davenport et al., which is incorporated herein by reference in its entirety.

The substrate support140may be comprised of aluminum or ceramic. The substrate support140may be an electrostatic chuck, a ceramic body, a heater or a combination thereof. In one embodiment, the substrate support140is an electrostatic chuck that includes a dielectric body106having a conductive layer112embedded therein. The dielectric body106is typically fabricated from a high thermal conductivity dielectric material such as pyrolytic boron nitride, aluminum nitride, silicon nitride, alumina or an equivalent material.

The lid assembly156generally includes a lid130, a target132, spacer182and a magnetron134. The lid130is supported by the sidewalls158when in a closed position, as shown inFIG. 1. Seals136are disposed between spacer182and the lid130and sidewalls158to prevent vacuum leakage therebetween.

The target132is coupled to the lid130and exposed to the interior volume160of the processing chamber150. The target132provides material which is deposited on the substrate104during a PVD process. The spacer182is disposed between the target132, lid130and chamber body152to electrically isolate the target132from the lid130and chamber body152.

The target132and pedestal assembly100are biased relative to each other by a power source184. A gas, such as argon, is supplied to the volume160from a gas source (not shown). A plasma is formed between the substrate104and the target132from the gas. Ions within the plasma are accelerated toward the target132and cause material to become dislodged from the target132. The dislodged target material is deposited on the substrate104.

The magnetron134is coupled to the lid130on the exterior of the processing chamber150. The magnetron134includes at least one rotating magnet assembly138that promotes uniform consumption of the target132during the PVD process. One magnetron which may be utilized is described in U.S. Pat. No. 5,953,827, issued Sep. 21, 1999 to Or et al., which is hereby incorporated by reference in its entirety.

A hinge assembly110couples the lid assembly156to the processing chamber150. A motorized actuator116may be coupled to the hinge assembly110and/or lid130to facilitate movement of the lid assembly156between an open and closed portion.

FIG. 2is a partial sectional view of the process kit114interfaced with the substrate support pedestal assembly100. Although not shown, the shield162of the process kit114is mounted to the chamber body152at a fixed elevation relative to the lid assembly156. The deposition ring102is shown in an elevated or process position in which a labyrinth gap250is defined between the deposition ring102and the ground shield162to confine the plasma and deposition species within the region defined between the substrate104and the target132. The deposition ring102and the ground shield162additionally provide a barrier that prevents ejected material from the target132from inadvertently depositing on other portions of the chamber. As such, the deposition ring102and the ground shield162promotes efficient transformation of the target132into a material layer deposited on the substrate104.

The ground shield162has a flat substantially cylindrical body202and may be fabricated from and/or coated with a conductive material, such as metal. Metals suitable for use as the ground shield162include stainless steel and titanium, among others. The material selected for the ground shield162should be selected to be compatible with processes preformed within the chamber. The body202is mounted to the chamber body152such that the centerlines of the body202and pedestal assembly100are substantially concentric. Centerline200of the body202shown in the embodiment ofFIG. 2and is oriented in a substantially vertical orientation. The position of the centerline200is merely illustrative and, along with other features of the Figures, is not to scale.

The body202includes an upper surface204, a lower surface206, an outer wall220and an inside edge224. In the embodiment depicted inFIG. 2, the upper surface204and lower surface206are substantially perpendicular to the centerline200, except for a sloped surface226of the upper surface204that slants downward towards the inside edge224of the body202.

Inner and outer rings208,210extend downward from the lower surface206. The rings208,210are generally elongated cylinders (as compared to the generally shape of the body202). In the embodiment depicted inFIG. 2, the rings208,210are orientated in a generally parallel, spaced apart relation. The outer ring210may also have an outer diameter that is the same as an outer diameter of the outer wall220.

A mounting section212extends upward from the upper surface204along the outer wall220. The mounting section212includes an inner wall214, and an inner taper216, an outer wall222and a mounting flange218. The inner wall214extends upwards in a substantially perpendicular orientation from the upper surface204to the inner taper216. The inner taper216extends upward and outward to provide clearance between the shield162and the target130(shown inFIG. 1). The outer wall222generally has a diameter greater than the outer diameter of the outer wall220of the body202.

The mounting flange218extends outward from the outer wall222and engages the body152and/or lid assembly156to secure the shield162in position. The mounting flange218may includes a plurality of holes and/or slots to facilitate coupling to the body152and/or lid assembly156. As the body152and/or lid assembly156to which the shield162is mounted is thermally regulated, temperature control of the mounting flange218is enabled via conduction.

Some portions of the ground shield162may be coated, textured or otherwise treated. In one embodiment, the ground shield162is roughened on at least some surfaces. Roughening (e.g., texturizing) may be accomplished by etching, embossing, abrading, bead blasting, grit blasting, grinding or sanding, among other suitable processes. In the embodiment depicted inFIG. 2, all surfaces of the ground shield162are bead blasted. The bead blasted surfaces of the ground shield generally have an RA surface finish of about 250 or greater microinches.

The deposition ring102has a flat substantially cylindrical body252and may be made from a conductive or non-conductive material. In one embodiment, the deposition ring102is fabricated from a ceramic material, such as quartz, aluminum oxide or other suitable material.

The body252generally includes an outer portion274, an inner portion276, a lower surface256and an upper surface254. The upper surface254includes a recess258that accommodates the lip228of the shield162when the shield162and ring102are positioned approximate each other. The lower surface256is configured to sit on a ledge240formed at the perimeter of the pedestal assembly100. The lower surface256may be flat and/or have a smooth surface finish to promote good thermal contact with the ledge240. The relatively large (as compared to conventional designs) contact area between the lower surface256and ledge240, along with the relatively thin ring sectional area of the body252provides excellent heat transfer between the ring102and pedestal assembly100. As such, the temperature of the ring102may be readily maintained at a constant temperature through heat transfer with the pedestal assembly100.

In one embodiment, one or more temperature control elements246may be disposed in the pedestal assembly100directly below the ledge240to enhance temperature control of the ring102independent from features of the pedestal assembly100utilized to control the temperature of the substrate104. The temperature control elements246may include one or more of conduits for flowing a heat transfer fluid therethrough, resistive heating elements and the like. The output of the temperature control elements246is controlled by one or more appropriate temperature control sources248, such as a power source, heat transfer fluid supply and the like.

An inner wall260extends upward from the inner portion276to a substrate supporting flange262. The inner wall260has an inside diameter selected to maintain a gap between the wall260and a step242coupling the ledge240to a top surface244of the pedestal assembly100. The inner wall260has a height selected to maintain a gap between the flange262of the ring102and the top surface244of the pedestal assembly100.

The substrate supporting flange262extends inward from the upper end of the inner wall260and covers the outer edge of the top surface244of the pedestal assembly100. In one embodiment, the flange262is generally perpendicular to the inner wall260and parallel to the lower and upper surfaces256,254. The flange262includes a plurality of substrate support buttons264that support the substrate104spaced above the upper surface of the flange262. The buttons264may have a rounded shape, a cylindrical shape, a truncated conical shape, or other suitable shape. The buttons264minimize the contact between the substrate104and ring102. The minimal contact between the buttons264and substrate104reduces potential particle generation while minimizing heat transfer between the ring102and substrate104. In one embodiment, three buttons264are symmetrically arranged in a polar array and have a height of about 1 mm.

An upwardly facing u-channel266is generally formed at the outer portion274of the body274. The u-channel266has an inner leg268coupled to an outer leg272by a bottom270. The inner leg268extends downward from the lower surface256of the body252and has an inside diameter selected to maintain a gap between the pedestal assembly100and the ring102.

The legs268,272are generally elongated cylinders (as compared to the body252of the ring102). In the embodiment depicted inFIG. 2, the legs268,272are orientated in a generally parallel spaced apart relation and configured to interleave with the inner ring208of the ground shield162.

The spacing the between the legs268,272and inner ring208defines the outer region of the labyrinth gap250. The inner region of the labyrinth gap250is defined between the lip228of the shield162and the wall260and recess258of the deposition ring102. The spacing between the lip228and deposition ring102may be selected to promote or minimize deposition on the side of the substrate104facing the pedestal assembly100.

As the entry into the inner region of the labyrinth gap250is partially covered by the substrate104and faces away from the trajectory of sputtered target material in the interior volume160, deposition build up and bridging within the labyrinth gap250is less likely to occur as compared to conventional designs, thereby extending the service life between cleanings of the process kit114. Moreover, as the deposition ring102and ground shield162of the process kit114never come in contact, a potential source of particle generation is eliminated. Furthermore, as the deposition ring102and ground shield162of the process kit114remain in good thermal contact with their supporting structures (e.g., the pedestal assembly100and chamber body152/lid assembly156), thermal control of the kit114is enhanced. The enhanced thermal control enables stress management of films deposited on the kit114, resulting in less particle generation as compared to conventional designs.

FIG. 3is a sectional view of another embodiment of a process kit300interfaced with a substrate support pedestal100. The process kit300generally includes a deposition ring302and a ground shield304that are interleaved to form a labyrinth gap350.

The ground shield304is generally similar to the ground shield described above. In the embodiment depicted inFIG. 3, the shield304includes a cylindrical body306having an upper surface308, a lower surface310, an inside edge312and an outer wall314. The upper surface308includes a sloped surface316. The lower surface310of the body306includes inner and outer rings208,210. In one embodiment, the inside edge312substantially truncates the sloped surface316

The deposition ring302is generally similar to the deposition ring described above with the addition of a trap352formed on an upper surface254of the ring302. The trap352is defined between a trap wall360and the upper surface254of the ring302.

The trap wall360includes a ring354extending upward from the upper surface254of the ring302to a lip356. The lip356extends inward and downward toward junction of the inner wall260and upper surface254. The distal end of the lip356is generally closer to the upper surface254than the portion of the lip356next to the ring354such that the upper ceiling of the trap352is higher than the distal end of the lip356. This geometric facilitates capture of deposition material without deposition build-up, thus preventing bridging of the gap defined between the lip356and substrate104.

In one embodiment, the top surface of the ring354includes an inner sloped wall364and an outer sloped wall362that meet at an apex366. The inner sloped wall364extends downward from the apex366to the lip356. The outer sloped wall362extends downward from the apex366to the outer trap wall368. The outer sloped wall362of the deposition ring302and the inside edge312of the shield304define the entrance to the labyrinth gap350from the processing region of the interior volume160.

The process kit300ofFIG. 3decouples the plasma isolation feature via the labyrinth gap350from edge deposition control via the trap352. Additionally, manufacturing costs are reduced with in this embodiment as the distance between inside and outer diameters of the shield304is substantially reduced without significant increase to the material need to fabricate the mating deposition ring302.

FIG. 4is a sectional view of another embodiment of a process kit400interfaced with a substrate support pedestal100. The process kit400generally includes a deposition ring402and a ground shield404that are interleaved to form a labyrinth gap450.

The ground shield404is generally similar to the ground shield described above with reference toFIGS. 1-2. In the embodiment depicted inFIG. 4, the shield404includes a flat cylindrical body406having an upper surface408, a lower surface410, an inside edge412and an outer wall414. The upper surface408includes a sloped surface416. The lower surface410of the body406has a cylindrical ring418.

The cylindrical ring418extends downward and outward and interleaves with the deposition ring402. In the embodiment depicted inFIG. 4, the ring418has an orientation of about 5 to about 35 degrees relative to the centerline of the shield404.

The deposition ring402is generally similar to the deposition ring described above with the addition of an inclined u-channel420. The u-channel420includes an inner leg422coupled to an outer leg424by a bottom426. The legs422,424have an orientation of about 5 to about 35 degrees relative to the centerline of the ring402. In the embodiment depicted inFIG. 4, the legs422,424are oriented at the same angle as the cylindrical ring418of the shield404.

An inside diameter of the distal end of the outer leg424is generally selected to clear the distal end of the ring418so that the shield404and deposition ring402may be separated without interference when the pedestal assembly100is lowered to facilitate substrate exchange. When the pedestal assembly100is raised to a process position as shown inFIG. 4, the legs422,424and ring418define an outer portion of the labyrinth gap450.

Optionally, an extension430(shown in phantom) may be formed at the distal end of the outer leg424. The extension430lengthens and adds additional turns to the labyrinth gap450. The extension430includes a flange432and terminal ring434. The flange432extends outward from the distal end of the outer leg424to the terminal ring434. The terminal ring434has an inner diameter selected to circumscribe the outer wall414of the shield404in a spaced apart relation when the pedestal assembly100is in the raised position as shown.

The process kit400ofFIG. 4is economical to manufacture and possesses advantages over conventional designs as described above.

FIG. 5is a sectional view of another embodiment of a process kit500interfaced with a substrate support pedestal100. The process kit500generally includes a deposition ring502and a ground shield504that are interleaved to form a labyrinth gap550.

The ground shield504is generally similar to the ground shield described above with reference toFIGS. 3-4. In the embodiment depicted inFIG. 5, the shield504includes a cylindrical body506having an upper surface308, a lower surface310, an inside edge312and an outer wall314. The upper surface308includes a sloped surface316. The lower surface310of the body306includes a cylindrical ring418. The cylindrical ring418extends downward and outward and interleaves with the deposition ring502.

The inside portion of the deposition ring502is generally similar to the deposition ring302described above with reference toFIG. 3. The ring502includes a trap352formed on an upper surface254of the ring502. The trap352is defined between a trap wall360and the upper surface254. The trap wall360includes a ring354, a lip356, and sloped walls262,264meeting at an apex366.

The outer portion of the deposition ring502is generally similar to the deposition ring402described above with reference toFIG. 4. The ring502includes an inclined u-channel420. The u-channel420includes an inner leg422coupled to an outer leg424by a bottom426. The legs422,424are configured to interleave with the cylindrical ring418of the shield504as discussed above.

FIG. 6is a sectional view of another embodiment of a process kit600interface with a substrate support pedestal100. The process kit600generally includes a deposition ring620and a ground shield662that are interleaved to form a labyrinth gap650. The deposition ring620and the shield622are substantially similar to the deposition ring102and ground shield162described above, and as such, similar features are provided with identical reference numerals without further description for the sake of brevity.

In the embodiment depicted inFIG. 6, the inner wall260of the deposition ring620has a substrate support end622. The substrate support end622does not extend radially inward of the inner wall260. The substrate support end622provides a substrate seating surface configured to support the substrate104above the surface244of the pedestal assembly100, and in one embodiment, is substantially flat and perpendicular to the center line of the ring620. In one embodiment, the inner wall260has a height of about 0.45 inches. The intersection between the inner wall260and the lower surface256of the deposition ring flange262may be chamfered, for example, at a 45-degree angle, to provide additional clearance with the pedestal assembly100.

In the embodiment depicted inFIG. 6, the deposition ring620may also be texturized on its upper surface, as indicated by dashed line624. The texturized surface provides improved adhesion of material deposited on the ring620so that particles or flakes of deposited material do not easily become detached from the ring620and become process contaminants over the course of processing. Such adhered deposited material may be removed from the ring620utilizing an in-situ and/or ex-situ cleaning process. In one embodiment, the ring may be texturized as described above.

The ground shield662includes a mounting section212having a step606formed in an upper outer diameter604. The step606couples the outer diameter604to a substantially horizontal upper surface602. A transition radius608couples the outer wall222of the ground shield662and the upper outer wall604.

A lip610extends downward from the upper outer wall604and beyond the transition radius608, as shown inFIG. 6. The lip610provides a reduced contact area between the processing chamber and the ground shield662.

The upper inner surface of the ground shield662may also be texturized, as indicated by dashed line654. As discussed above, the textured surface of the ground shield provides improved adhesion of deposition materials so that they may not later become process contaminants.

The lip228of the ground shield662may also include a recess612formed at the transition between the lip228and the lower surface206of the shield body202. the recess612provides extra clearance between the shield662and the ring620to accommodate a large amount of material deposited in the recess258of the ring620.

As with the process kits described above, the process kit600ofFIG. 6is economical to manufacture and possesses advantages over conventional designs as described above.

Thus, a process kit for a PVD process chamber has been described that advantageously reduces the potential for particulate generation as the ground shield and deposition ring of the process kit do not contact during operation. Moreover, as the shield and ring of the kit are maintained in contact with surfaces that are temperature controlled, the temperature of the process kit may be controlled to reduce and/or eliminate thermal cycling, thereby allowing management of stress included in materials deposited on the process kit. Furthermore, the process kit of the present invention provides an attractive cost of fabrication due to a compact design and elimination of the third ring present in conventional process kits.