Screwless shield assembly for vacuum processing chambers

We claim:

1. The configuration for attaching a shield to a substrate processing chamber comprising:

a substrate processing chamber having walls surrounding a substrate processing location, a top edge of said walls forming a chamber opening;

a chamber opening cover member spanning said opening and configured to be sealed to said top edge of said chamber walls;

a shield configured to act as at least a partial barrier preventing process constituents emanating from the substrate processing location from reaching the walls, said shield including an integral flange piece which is securely held and clamped by a clamping force between a portion of said chamber wall and a portion of said chamber opening cover member, wherein at least part of the clamping force to hold and clamp the flange portion is created by evacuation of the substrate processing chamber which causes the cover member and said top edge of said chamber walls to be urged together;

wherein said flange piece is disposed at a spacer location between said walls of said processing chamber and said chamber opening cover member within said processing chamber and internal to the seal path of a flange sandwich of said chamber opening, wherein the chamber is gas tightly sealed by seals in said flange sandwich;

wherein said shield is configured so that in use removal and replacement of the shield is done without removal and replacement of a set of removable fasteners which in use are disposed inside the processing chamber.

2. The configuration for attaching a shield to a substrate processing chamber as in claim 1;

wherein said flange piece as a result of the cover member being urged toward said top edge of said walls of said chamber is urged toward said walls of said chamber and has electrical continuity with the walls of the chamber.

3. A configuration for attaching a shield to a substrate processing chamber comprising:

a substrate processing chamber assembly having one or more walls surrounding a substrate processing location, a top surface of the one or more walls forming an opening of said chamber,

a chamber opening cover member being configured to cover the opening of said chamber generally supported from and sealed to said top surface of said one or more walls;

an insulating ring to electrically isolate the one or more walls of the processing chamber from the chamber opening cover member, the insulating ring is generally configured to be disposed between said top surface of the walls of said chamber and said chamber opening cover member, generally vacuum tight seals being formed between the insulating ring and the top surface of the one or more walls of said chamber and between the insulating ring and said chamber opening cover member;

a first process chamber shield disposed to act as an internal liner for said one or more walls generally adjacent said substrate processing location, a portion of said shield in use generally acting as a barrier to prevent particles emitted from the processing location from reaching at least a portion of the processing chamber walls, said first process chamber shield including a flange portion;

a compliant spacer ring located within the processing chamber, said compliant spacer ring being configured to contact said flange portion and together with the flange portion form at least part of a shield clamping assembly, said shield clamping assembly being configured to clamp said flange portion at a spacer location located between said insulating ring and a clamping portion of said one or more walls of said processing chamber assembly, said compliant spacer ring in use providing contact pressure between adjacent members in the shield clamping assembly to assure electrical continuity between the flange portion of said shield and the one or more walls of the processing chamber assembly when a generally vacuum tight seal is formed to permit evacuation of gas molecules present in the processing chamber.

4. The configuration for attaching a shield to a substrate processing chamber as in claim 3,

wherein said compliant spacer ring includes a generally rigid ring with a cavity therein, said cavity receiving a generally compressible elastic member which in an uncompressed state protrudes beyond a mouth of said cavity and which in use is at least partially compressed and exerts a force on adjacent members in the shield clamping assembly so long as the elastic member is displaced from its uncompressed state.

5. The configuration for attaching a shield to a substrate processing chamber as in claim 4,

wherein said cavity is a generally continuous groove around said rigid ring, and said elastic member is a tubular structure laid in said groove where a side portion of said tubular structure protrudes beyond the mouth of said cavity.

6. The configuration for attaching a shield to a substrate processing chamber as in claim 3,

wherein said one or more walls of said processing chamber assembly includes an adapter ring generally configured to be disposed between said top surface of the walls of said chamber and said insulating ring, a generally vacuum tight seal being formed between the adapter ring and the top surface of the one or more walls of said chamber and between the insulating ring and said adapter ring.

7. The configuration for attaching a shield to a substrate processing chamber as in claim 3,

wherein said shield clamping assembly further includes a clamping ring disposed between said compliant spacer ring and said insulating ring.

8. The configuration for attaching a shield to a substrate processing chamber as in claim 7,

wherein said clamping ring includes at least one gas passage there through to provide for gas flow from a first side to a second side of said clamping ring without the need for there to be a gas flow path across the surface of the clamping ring between said first and second sides.

9. The configuration for attaching a shield to a substrate processing chamber as in claim 3, further comprising:

a second process chamber shield disposed to act as an internal liner for said one or more walls generally adjacent said target material, said shield in use generally acting as a barrier to prevent particles emitted from the substrate processing location from reaching at least a portion of the processing chamber walls, said second process chamber shield including a flange portion;

wherein said flange portion of said first shield is disposed on one side of said compliant spacer ring in said chamber and said flange portion of said second shield is disposed on a second side of said compliant spacer ring as part of said shield clamping assembly,

wherein said second shield acts as an inside liner for a portion of said first liner.

10. The configuration for attaching a shield to a substrate processing chamber as in claim 3, further comprising:

a second process chamber shield disposed to act as an internal liner for said one or more walls generally adjacent said substrate processing location, a portion of said second shield in use generally acting as a barrier to prevent particles emitted from the substrate processing location from reaching at least a portion of the processing chamber walls, said second process chamber shield including a flange portion;

wherein said flange portions of said first shield and of said second shield are disposed adjacent to one another and on a first side of said compliant spacer ring in said chamber as part of said shield clamping assembly,

wherein said second shield acts as an inside liner for portion of said first liner.

11. The configuration for attaching a shield to a substrate processing chamber as in claim 3,

wherein said compliant spacer ring generally acts as a floating elastically compressible spacer unit to assist in clamping the flange portion of said first shield in electrical contact with said one or more walls of said processing chamber.

12. The configuration for attaching a shield to a substrate processing chamber as in claim 3,

wherein said first shield generally spans a gap between the edge of a pedestal supporting the substrate to be processed and the one or more walls of the processing chamber.

13. A method of attaching a shield to a substrate processing chamber comprising the steps of:

providing a process chamber wall assembly surrounding a substrate processing location of the processing location;

placing a flange of an overspray shield in a spacer sandwich with a compliant spacer ring at a spacer location internal to said processing chamber wall, said compliant spacer ring having an elastic member which when compressed by an adjacent member urges the adjacent member away from said compliant spacer ring;

positioning a chamber opening cover member opposite said substrate processing location,

creating a gas tight seal between an outer portion of said wall assembly and said chamber opening cover member,

wherein a portion of said chamber opening cover member includes a surface internal to a seal location of said cover member, said surface facing said spacer location such that the spacer sandwich is compressed between said wall assembly and said surface when a gas tight seal is created at said seal location between an outer portion of said wall assembly and said chamber opening cover member and said processing chamber is at least partially evacuated.

14. A configuration for attaching a shield to a substrate processing chamber comprising:

a substrate processing chamber assembly having one or more walls surrounding a substrate processing location, a top surface of the one or more walls forming an opening of said chamber,

a chamber opening cover member being configured to cover the opening of said chamber generally supported from and sealed to said top surface of said one or more walls;

an insulating ring to electrically isolate the one or more walls of the processing chamber from the chamber opening cover member, the insulating ring is generally configured to be disposed between said top surface of the walls of said chamber and said chamber opening cover member, generally vacuum tight seals being formed between the insulating ring and the top surface of the one or more walls of said chamber and between the insulating ring and said chamber opening cover member;

a first process chamber shield disposed to act as an internal liner for said one or more walls generally adjacent said substrate processing location, a portion of said shield in use generally acting as a barrier to prevent particles emitted from the processing location from reaching at least a portion of the processing chamber walls, said first process chamber shield including a flange portion;

a spacer ring located within the processing chamber, said spacer ring being configured to contact said flange portion and together with the flange portion form at least part of a shield clamping assembly, said shield clamping assembly being configured to clamp said flange portion at a spacer location located between said insulating ring and a clamping portion of said one or more walls of said processing chamber assembly, said spacer ring in use providing contact pressure between adjacent members in the shield clamping assembly to assure electrical continuity between the flange portion of said shield and the one or more walls of the processing chamber assembly when a generally vacuum tight seal is formed to permit evacuation of gas molecules present in the processing chamber,

wherein said spacer ring includes a generally rigid ring with a cavity therein, said cavity receiving a generally compressible elastic member which in an uncompressed state protrudes beyond a mouth of said cavity and which in use is at least partially compressed and exerts a force on adjacent members in the shield clamping assembly so long as the elastic member is displaced from its uncompressed state.

15. The configuration for attaching a shield to a substrate processing chamber as in claim 14,

wherein said cavity is a generally continuous groove around said rigid ring, and said elastic member is a tubular structure laid in said groove where a side portion of said tubular structure protrudes beyond the mouth of said cavity.

16. A configuration for attaching a shield to a substrate processing chamber comprising:

a substrate processing chamber assembly having one or more walls surrounding a substrate processing location, a top surface of the one or more walls forming an opening of said chamber,

a chamber opening cover member being configured to cover the opening of said chamber generally supported from and sealed to said top surface of said one or more walls;

an insulating ring to electrically isolate the one or more walls of the processing chamber from the chamber opening cover member, the insulating ring is generally configured to be disposed between said top surface of the walls of said chamber and said chamber opening cover member, generally vacuum tight seals being formed between the insulating ring and the top surface of the one or more walls of said chamber and between the insulating ring and said chamber opening cover member;

a first process chamber shield disposed to act as an internal liner for said one or more walls generally adjacent said substrate processing location, a portion of said shield in use generally acting as a barrier to prevent particles emitted from the processing location from reaching at least a portion of the processing chamber walls, said first process chamber shield including a flange portion;

a spacer ring located within the processing chamber, said spacer ring being configured to contact said flange portion and together with the flange portion form at least part of a shield clamping assembly, said shield clamping assembly being configured to clamp said flange portion at a spacer location located between said insulating ring and a clamping portion of said one or more walls of said processing chamber assembly, said spacer ring in use providing contact pressure between adjacent members in the shield clamping assembly to assure electrical continuity between the flange portion of said shield and the one or more walls of the processing chamber assembly when a generally vacuum tight seal is formed to permit evacuation of gas molecules present in the processing chamber,

wherein said shield clamping assembly further includes a clamping ring disposed between said spacer ring and said insulating ring,

wherein said clamping ring includes at least one gas passage there through to provide for gas flow from a first side to a second side of said clamping ring without the need for there to be a gas flow path across the surface of the clamping ring between said first and second sides.

Description Submit all comments and votes

FIELD OF THE INVENTION

This invention relates to substrate processing in vacuum processing chambers and in particular to the configuration and method of mounting of shields or liners within such chambers.

BACKGROUND OF THE INVENTION

In the semiconductor industry vacuum chambers are used to deposit materials on, or etch materials from the surface of substrates. Some examples of the types of materials deposited include thin films of aluminum and aluminum alloys, refractory metal silicides, gold, copper, titanium-tungsten, tungsten, molybdenum, and silicon dioxide and silicon on an item, for example a substrate or wafer being processed. Ion, chemical, and plasma based etching is also performed in vacuum chambers. In many of these chambers the actual geometric arrangement of the substrate relative to the source from which the material being deposited determines the uniformity, quality, and efficiency of the material deposited or of the etching taking place. Typically a gas distribution plate or a sputtering target or ion source is placed opposite the substrate being processed. Processing occurs when active elements in the chamber contact the surface of the substrate being processed. For example when a reactive gas, in some cases charged to form a plasma, comes in contact with the surface of the substrate deposition occurs. Chemicals or ions which form part of an etch process also perform their function only when they contact the surface of the substrate (sometimes selectively).

Even though the space between the source of active elements, e.g. a gas distribution plate or an ion source, is usually small the scatter of the active particles in all directions causes the surface of the surrounding members to receive the same effect that is being directed toward the substrate being processed. The surrounding members are typically the walls of the vacuum processing chamber. The walls of the vacuum processing chamber could and do thereby become coated or etched (if affected by the etch process) during the processing of the substrate. Built-up deposited material can flake off creating particulates which can create defects when they land on the substrate surface. The surfaces of members surrounding the processing location are therefore periodically cleaned to reduce or nearly eliminate the likelihood that flaking from surrounding members will create defects. The walls of vacuum chambers in which etching occurs can wear away over time requiring that the wall of the chamber be replaced. Etching and mechanical abrasion are used in nearly all deposition chambers to remove the build-up of deposited material. Therefore the wear that takes place in etch chambers is also experienced in deposition chambers. Since the surfaces surrounding the substrate processing location are usually the walls of the vacuum processing chamber, excessive wear could require replacement of the walls of the processing chamber. Which is both time consuming and expensive.

To postpone the replacement of such walls the surfaces of surrounding members are often lined by chamber shields which directly face the substrate processing location and shield the walls and surfaces of other surrounding components from the deleterious effects of the process acting on the substrate being processed. Such shields, usually electrically conductive, in many cases they must be in electrical contact (have continuity) with the surrounding surfaces to avoid discontinuities in the electrical and magnetic fields which contribute to the qualities and properties desired as materials are deposited on or etched from the surface of the substrate being processed.

For example, an existing PVD chamber (i.e., sputtering chamber), is shown in FIG. 1. A substrate 30 to be processed at a substrate processing location is shown in an evacuated processing chamber 20. The substrate 30 is supported on a pedestal 28 and faces a target assembly 60, the source of the material to be sputter deposited. The wall 22 of the chamber is sealed by O-rings 26, 40 and 74. The target assembly O-ring 74 seals the top (target) opening of the processing chamber to provide a gas tight chamber which can be evacuated. In use, the target assembly 60 is electrically biased (charged) to a predetermined voltage to facilitate sputtering. The target assembly 60 is therefore electrically isolated from the grounded or neutral potential chamber wall by an insulating ring 58 (often made of a ceramic material).

From the configuration as shown in FIG. 1 it is clear that the target assembly 60 is larger than the substrate 30. The size differential provides for nearly uniform bombardment of free atoms from all directions to sputter deposit material on the surface of the smaller substrate which improves the coverage and uniformity of thin film deposited. However, targets (especially larger targets like the one shown) when sputtered will sputter deposit material (free atoms) not only on the substrate being sputtered, but also all other surfaces which are directly exposed to the path of free atoms from target surface (i.e. substrate processing location). Outside the area of the substrate, the "overspray" of sputter deposited material coats all surfaces exposed to the sputter processing location. As a result target material is deposited to build up on and potentially contaminate all exposed surfaces. The surfaces facing the substrate processing location which are closer to the target surface generally receive a higher concentration of particles than surfaces farther away (the inverse square of the distance relationship), thus the thickness of sputter deposited material builds up more quickly on surfaces which are closer to the target surface and less quickly on more distant surfaces.

Other vacuum chamber substrate processing chamber configurations do not include a target assembly, but include some type of chamber opening covering member such as a gas distribution plate which is a source for material to be deposited or for etchant gas.

Overspray shields have been developed as partial or full chamber liners to reduce and/or eliminate the need to repeatedly clean the walls of the processing chamber to remove material deposited on their surface.

As pictured in FIG. 1, an overspray shield assembly 42 (typically aluminum, stainless steel or titanium) is roughly finished by either stamping or spinning it into its final configuration. These processes for forming the overspray shield are economical, but result in an imprecise dimensional tolerance and rough surface finish for the thickness of the shield flange 46. To eliminate any deleterious effect of the imprecise dimension (such as providing resistance to electrical conductivity), the shield flange 46 is clamped to an adapter ring 36 by a circumferential clamping ring 52 held tightly by a series of 8 to 16 clamping screws 54. The clamping ring 52 is configured to fit loosely into the space above the shield flange 46 and together with a close portion of the shield is oriented to provide a dark space ring gap 72--which provides a prescribed clearance between the target and its immediately adjacent pieces to deter sputtering of the edge of the target. The gap 56 between the clamping ring 52 and an insulating ring 58 results from the loose fit between the clamping ring 52 and its adjacent pieces (the insulating ting 58 and the target assembly 60) and is maintained to accommodate the largest expected dimensional variations in the thickness of the shield flange.

The shield assembly 42 includes a shield body portion 44 which has a generally annular shape and is generally configured to span the gap between the wall of the process chamber adjacent to the target surface (adjacent to the dark space ring gap 72) and the edge of the pedestal 28 supporting the substrate 30 being processed.

Clamping of the shield flange 46 to the adapter ring 36 attempts to assure that the shield 44 is electrically grounded or neutral (i.e., tied to the adapter ring 36) so that a uniform electrical potential with the chamber wall can be maintained to avoid distorting the deposition pattern due to variations in the charge (potential) present in surrounding members. Electrical connection (continuity) is ostensibly assured by a clamping ring 52 which clamps the shield flange 46 to a shelf 50 of the adapter ring 36. The adapter ring 36 is positioned on top of the circular opening of the flange and acts as part of the wall of the processing chamber assembly. An insulator ring 58 sits on the adapter ring 36 and O-rings 26, 40, 74 in O-ring grooves 24, 38, 74 are provided to seal the wall of the processing chamber assembly.

In use, the overspray shield 44 as shown in FIG. 1 must be periodically (e.g., weekly) removed and replaced (otherwise the build-up of material on this shield could flake off particulates which might contaminate the substrate being processed). This requires that the adapter ring 36 still clamped to the shield assembly 42 be removed. The screws 54 can then be unscrewed to release the clamping ting 52 and shield flange 46. A new shield assembly 42 can then be attached to the adapter ring 36 by re-tightening the screws 54 holding the clamping ring 52. The adapter ring 36 with the shield assembly 42 clamped to it must then be placed back in position and precisely positioned in relation to adjacent members to assure that the processing chamber can be sealed for subsequent evacuation and processing.

The weekly or more frequent release and re-tightening of the many screws 54 around the clamping ring 52 causes rubbing between adjacent metal pieces which generates micron size particles which can and do act as particulates deleterious to the PVD process in the evacuated environment of the processing chamber. The metal particles generated can and do find their way to the substrate being sputter deposited. In some instances the introduction of a potentially conductive particulate will create a change in electrical properties on the substrate which will cause rejection of the entire substrate. Every rejected substrate reduces overall productivity.

Similarly, the disassembly and reassembly of the adapter ting assembly using screws and dependence on correct tightening of the screws by technicians creates the risk of the screwed joint loosening under the repeated thermal cycling and vibration of the process environment. If the clamping is not done properly a good electrical contact between adjacent members is not made and then the bias voltage at the substrate level (ion current) (normally 20 volts DC) can increase (to 50 or 100 volts DC), to achieve conditions under which arcing (which also generates undesirable particles) can occur.

The gas in the chamber is usually argon or nitrogen at pressures of one to 10 millitorr. These pressures facilitate reactive sputtering using N.sub.2 to treat the surfaces, for example creating titanium nitrate.

The repeated removal and replacement of the shield assembly 42 and removal and replacement of the clamping ting 52 and the screws 54 holding the clamping ring in place generates undesirable particulates, which if eliminated, will reduce the down time and increase productivity in PVD and other vacuum processing chambers. The removal and replacement of removable screws in the shield assembly arrangement is also a time-consuming activity which can delay subsequent processing steps.

SUMMARY OF INVENTION

This invention eliminates particulates generated in the prior art, for example from rubbing contact, by providing a structure and method which includes nearly direct access to the overspray shield for removal and replacement without the need to remove an adapter ring and/or spend the time to remove and re-tighten screws to clamp a shield in place.

A configuration according to the invention includes a loose sandwich of rings (a shield clamping assembly) positioned and clamped during processing between a top surface of the walls of the processing chamber and a flange of the chamber opening cover member (the target--in PVD chambers). When the chamber assembly is properly assembled a vacuum tight seal is achieved; when not properly assembled gaps for leakage exist and no seal is achieved. In use, the differential pressure between the evacuated processing chamber and the ambient pressure around the processing chamber creates a tremendous clamping forces which compresses the shield clamping assembly (e.g., a shield separately or as part of a loose sandwich of rings) to tightly hold the flange of an overspray shield (also part of the shield clamping assembly and in some instances the only component of the shield clamping assembly extending beyond the wall of the processing chamber and its chamber opening cover member in electrical contact with its adjacent conductive members (i.e., the adapter ring and/or the wall(s) of the processing chamber).

In one configuration the outer flange of the shield is precisely manufactured with dimensional tolerances and a surface finish which are conducive to being captured in the flange sandwich of the processing chamber and to act as part of the seal sealing the vacuum chamber. The flange generally includes continuous sealing surfaces on its surfaces against which O-rings can be placed for sealing.

In another configuration which can be compared with the prior art configuration described in the Background of the Invention, uses a shield configuration having a flange with the dimensional variations of economically manufactured shields. A ledge or shelf of the adapter ring supports a spacer ting having two O-ring type circumferential grooves at a spacer location between the adapter ring and the insulator ring. The two O-ring type grooves are filled with an elastic (spring) member. (Preferably a hollow spring O-ring shaped member--a metal ribbon tightly wounded in a spiral so that the outside of the spiral forms a generally circular hollow core cylinder, the ends of which are joined or brought into close contact with one another. From the outside the spring member tends to look like an O-ring with some spiral grooves or openings.) The side surface of the elastic members extend beyond the mouths of the spacer ring grooves and act as a compliant set of continuous spring contacts to maintain electrical continuity between the spacer ring and its adjacent conductive members. The elastic (compressive) range of such a spacer ring effectively accommodates variations in the thickness of the shield flange while continuing to assure electrical contact with it.

In the configuration described, the shield clamping assembly includes a loose sandwich of rings including: the perimeter top edge flange of the overspray shield, a spacer ring, and a floating clamping ring. The floating clamping ring in one configuration sits on top of the perimeter flange of the overspray shield and is clamped tightly to it by the insulator ring which presses the floating clamping ring toward the fixed upper flange of the processing chamber. Under process conditions when a vacuum is present in the processing chamber, the shield clamping assembly tightly holds the overspray shield in electrical contact with the adapter ring and the wall(s) (one or more) of the processing chamber.

A configuration according to the invention provides easy maintenance of the shield assembly such that once the chamber opening cover member and insulator ring are removed only a floating clamping ring need be removed in order to access, remove, and replace the shield flange and its associated shield assembly. In another configuration the spacer ring can function as a clamping ring. While it may be possible to eliminate the clamping ring function apart from the compliant spacer ring function, such a configuration is not preferred as the non-uniformities in the thickness of the overspray shield flange can cause areas of variable stress around the circumference of the insulating ring. Since the insulating ring is generally made of a brittle ceramic material, large variation (or concentration) in stress may contribute to cracking and failure of the insulator ring. Therefore it is better to have an intermediate member (i.e., a clamping ring) with a precisely manufactured surface to face the insulating ring so that the variations in stress and its distribution can take place in the intermediate member which is usually a malleable metal tolerant of variations in stress.

In yet another configuration, the flange of the shield assembly is configured such that the shield flange is positioned below the spacer ring which is directly adjacent to the insulator ring above. In this configuration the spacer ring provides both elastic compliant contact with the shield flange and also acts as the intermediate member to distribute potential high stresses due to variations in the shield flange thickness dimension.

Other configurations to clamp the shield perimeter flange are possible. Such configurations include, but are not limited to, a perimeter shield flange positioned at a spacer location adjacent to the chamber wall assembly, the actual position of the spacer location and the angular orientation of the perimeter flange may vary (e.g., be inclined at 45 degrees), as long as the mating pieces (sandwich) of surrounding vacuum sealing members are in contact to provide a vacuum seal and the shield is in electrical contact with the chamber wall directly or through an adapter plate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section of a prior art PVD processing chamber using a screw clamped overspray shield;

FIG. 2 is a cross sectional view of a chamber sidewall construction according to the invention, showing a flange of an overspray shield sealed in the flange sandwich;

FIG. 2A is a cross sectional view of a chamber sidewall construction according to the invention, showing a flange of an overspray shield clamped in the flange sandwich, but with the chamber seal path outside the shield flange;

FIG. 3 is perspective view of a overspray shield of the type illustrated in FIG. 1 split along a dashed line;

FIG. 4 is an exploded perspective view of the overspray shield of FIG. 3, with the upper (flange) portion being shown in solid lines separated from the lower portion shown in dashed lines

FIG. 5 is an exploded perspective diagram showing an embodiment of a chamber wall of a processing chamber including an upper (flange) portion of the overspray shield and its clamping members according to the invention;

FIG. 6 is a cross section of a wall of a processing chamber of FIG. 5 according to the invention configured to capture the flange of a one piece overspray shield member;

FIG. 7 is a cross section of a wall of a processing chamber according to the invention configured to capture two flanges of shield members; the flanges located both on the top and the bottom of a spacer according to the invention;

FIG. 8 is a cross section of a wall of a processing chamber according to the invention configured to capture two flanges of shield members; the flanges located adjacent to one another on one side of a spacer ring according to the invention;

FIG. 9 is a cross section of a groove configuration of an elastic member in a spacer ring according to the invention - configured with plain parallel square cornered walls at the mouth of the groove; and

FIG. 10 is a cross section of a groove configuration of an elastic member in a spacer ting according to the invention - configured with a width dimension narrower at the mouth of the groove than the width dimension between the side walls closer to the bottom of the groove.

DETAILED DESCRIPTION

The present invention reduces the potential for particulate generation and facilitates easy insertion and removal of an overspray shield used in a substrate processing chamber by providing easy dis-assembly and re-assembly of the chamber wall including an edge flange around a processing chamber opening. A substrate processing chamber opening cover member fills the chamber opening and seals the opening. The differential pressure across the cover member creates a force to clamp the cover member to the flange of the chamber edge flange. An outer flange of a chamber inner shield is configured to be clamped by the clamping force clamping said cover member to said chamber edge flange.

In one configuration the flange is positioned within the sandwich of the chamber flange assembly and forms part of the chamber wall which creates the pressure (vacuum) seal sealing the chamber from outside atmosphere and also assures electrical continuity with the wall of the chamber. When the pieces in the flange sandwich are properly aligned they mate, so that the chamber can seal and a vacuum can be produced in the chamber. When alignment is not correct adjacent pieces do not mate and a tight vacuum cannot be maintained.

In another configuration an assembly of the chamber wall includes an outside seal and an inner compliant elastic fixture (structure) for holding (clamping) the overspray shield and assuring electrical continuity with the walls of the processing chamber (assembly) while providing easy screwless assembly of components.

FIG. 2 shows a cross section of chamber flange sandwich which is configured to capture a flange 142 of the top portion of the shield 144 between the top surface 150 of the flange 152 of the chamber wall 154 and the bottom of a clamping ring 148. The clamping ring 148 supports an insulator ring 146 which supports a chamber opening covering member 156. O-rings 160, 162, 164, 166 disposed in O-ring grooves 161, 163, 165, 167 provide seals between adjacent pieces.

FIG. 2A shows a cross section of chamber flange sandwich similar to FIG. 2 except that a flange 142a of the top portion of the shield 144a is captured and clamped between the top surface 150 of the flange 152 of the chamber wall 154 and the bottom of a clamping ring 148a. The clamping ring 148a includes a recess 149 whose depth is equal to the thickness of the flange 142a of the shield 144a. The fit/interference between the flange 148a and the chamber pieces being such that good electrical contact is achieved between the flange and the chamber wall, but the interference between pieces is not so great that it interferes with achieving a tight vacuum seal. The chamber seal path as shown in FIG. 2A is around the edge of the shield flange, while in FIG. 2 it includes and is through the shield flange.

FIG. 3 shows a shield configuration 42a of the type shown in FIG. 1, (prior art) discussed above. For the purposes of this discussion the actual shape of the shield 42a below the dashed line 41, separating the top portion 43 adjacent to the flange from the lower portion 45 is not important, but may be any configuration to act as a shield for the walls from the process being performed in the vacuum processing chamber.

FIG. 4 shows the separated sections of the shield 42a of FIG. 3. The bottom portion 45 shown in dashed lines could be configured in any particular shape desired for a particular process chamber configuration. The upper portion 43 including an outwardly extending flange 47 which is captured or clamped to the chamber wall to achieve good electrical contact and to hold the shield securely without excessive vibration.

FIG. 5 shows a perspective exploded view of chamber wall (flange) members according to the invention whose assembled cross-section is shown in FIG. 6.

The chamber wall 22, as seen in FIG. 6, is a series of hollow annular pieces or rings welded together to form a continuous cylindrical wall 22. The top of the