US 3856654 A
A magazine carrier drum is mounted within a vacuum housing to receive, at a load position, a magazine of radial arrayed substrate holders which are subsequently advanced seriatim into a carrousel mounted rotatably within a sputtering chamber. The carrousel advances the substrate holders about a centrally disposed cylindrical cathode whereafter the holders with film coated substrates are returned to the magazine carrier drum without breaking vacuum. Shields are provided to insure that each held substrate receives a uniform film deposit of the sputtered material. An arrangement of ducts, ports and shields control the uniform injection and diffusion of an ionizable gas or a mixture of an ionizable gas and a reactive gas. Facilities are also provided to control the cooling of the cathode and the sputtering chamber.
Claims available in
Description (OCR text may contain errors)
United States Patent 1 George 1 Dec. 24, 1974  Inventor: Carroll H. George, North Andover,
 Assignee: Western Electric Company,
Incorporated, New York, NY.
 Filed: Aug. 26, 1971  Appl. No.: 175,247
OTHER PUBLICATIONS M. R. C. catalog 89-12701000, December 1970.
Primary Examiner-John H. Mack Assistant Examiner-Wayne A. Langel Attorney, Agent, or FirmD. J. Kirk; R. P. Miller; A. S. Rosen [5 7] ABSTRACT A magazine carrier drum is mounted within a vacuum housing to receive, at a load position, a magazine of radial arrayed substrate holders which are subsequently advanced seriatim into a carrousel mounted rotatably within a sputtering chamber. The carrousel advances the substrate holders about a centrally disposed cylindrical cathode whereafter the holders with film coated substrates are returned to the magazine carrier drum without breaking vacuum. Shields are provided to insure that each held substrate receives a uniform film deposit of the sputtered material. An arrangement of ducts, ports and shields control the uniform injection and diffusion of an ionizable gas or a mixture of an ionizable gas and a reactive gas. Facilities are also provided to control the cooling of the cathode and the sputtering chamber.
14 Claims, 8 Drawing Figures APPARATUS FOR FEEDING AND COATING MASSES OF WORKPIECES IN A CONTROLLED ATMOSPHERE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to apparatus for feeding and coating masses of workpieces in a controlled atmosphere and, more particularly, to arrangements of apparatus for loading a mass of substrates, advancing the mass of substrates in a closed loop within a vacuum, and then feeding and withdrawing the substrates into and out of a controlled atmosphere coating chamber, e.g., sputtering or vapor deposition chamber, where the substrates are advanced in a circular path about a source of coating material.
2. Technical Considerations and Prior Art In the manufacture of many electronic or electrical components, such as integrated circuits, thin film tanta' lum nitride resistors, tantalum oxide capacitors, etc., there is a need to deposit metallic films on substrates. Materials such as gold, tantalum or tantalum nitride may be deposited on ceramic or glass substrates by a sputtering process and then etched or otherwise fabricated into the circuits and/or components. In sputtering, a cathode may be constructed of tantalum or a base metal with a tantalum coating and this cathode is subjected to a high voltage in an inert atmosphere such as argon, where the argon is ionized to bombard the exposed tantalum surface and dislodge atoms or clusters of atoms of tantalum which are deposited on the substrate.
Many manufacturing facilities have been developed for depositing thin films of metal on substrates. In one type of open end facility, the substrates are advanced through a series of individually pumped chambers of successively reduced pressure until the substrates enter a vacuum chamber where the sputtering takes place. In another type of continuous sputtering apparatus, the substrates are advanced through a series of locks which are successively evacuated and then the substrate enters a vacuum chamber to receive a sputtered deposit of metal. Even the sputtering of a relatively thin film takes considerable time; hence, these types of linear facilities are necessarily slow because so few substrates are being sputtered at a time.
In order to increase the number of substrates that are receiving a sputtered deposition, a bell jar arrangement may be utilized. In this arrangement substrates are positioned within the bell jar in a circular array about a centrally disposed cathode so that all substrates simultaneously receive a sputtered deposit of metal. This process does not lend itself to continuous operation in that the bell jar has to be pumped down for each batch of processed substrates. Further, in this process, the substrates are of a planar construction and receive nonuniform deposits of metal; more metal being deposited in the center area of each substrate due to the closer proximity of the center area to the centrally disposed cathode.
Many other problems exist in the sputtering of metal onto substrates, such as the need to outgas both the substrates and the substrate holders, the uniform distribution of both inert gasses and reactive gasses introduced into the sputtering atmosphere, and the dissipation and control of heat.
SUMMARY OF THE INVENTION This invention contemplates, among other things, apparatus for sputtering or otherwise coating thin films on a continuous procession of substrates wherein the substrates are batch loaded, fed seriatim to the sputtering apparatus, and then batch unloaded. More particularly, the substrates, mounted in trays, are loaded in a magazine and positioned in a first of a group of carriers or magazine chambers which is subsequently evacuated and advanced under vacuum into an outgas position and then into a position where the substrates are loaded seriatim into a sputtering chamber. The trays of substrates are advanced within the sputtering chamber in a circular path about a co-axially located hollow cylindrical cathode. The trays of substrates are incrementally advanced so that each substrate receives a uniform deposit of a thin film. During the time period between increments of advance of the trays, new trays of substrates are advanced into the sputtering chamber and trays of film-coated substrates are removed from the chamber. The cathode is provided with a unique system of ducts and ports through which an ionizable inert gas is emitted in such a fashion that the gas impinges on diffusion shields. Gas striking the shields is scattered across the face of the cathode so that the resultant plasma is of substantial uniform composition. During the sputtering operation, a substrate is positioned between a pair of shields. The shields may be constructed of the same material as the cathode and subjected to the same cathode voltage so that in effect the shields act as portions of the cathode. Inasmuch as the shields are aligned with the edges of the substrate and are closer to these edges than the remainder of the cylindrical cathode, there is a compensation to insure that the edge sections of the substrates receive substantially the same deposition of metal that the center sections of the substrates receive. The shields also act to preclude the ion penetration and deposition of metal vapors in the gas ports.
The invention also contemplates facilities for con trolling the temperature of both the substrates and the components constituting the sputtering chamber. Cooling water is circulated about the outer walls of the sputtering chamber and also within a structure supporting the hollow cylindrical cathode. The chamber is constructed of aluminum to more readily absorb the heat generated due to the sputtering action. The aluminum may be anodized to enhance the absorption and subsequent dissipation of heat. When it is desired to use the overall apparatus to sputter tantalum nitride, the substrates may be heated by providing the trays with stainless steel reflecting plates, which are positioned behind the substrates to reflect heat of deposition into the substrates.
Another feature of the invention resides in a seal arrangement utilizing O-rings wherein; the O-rings are engaged to provide double seals; that is, movement of the fluid from one chamber to another is precluded because the moving fluid is blocked by two engaged, spaced sections of the O-rings.
To further enhance the uniform deposition of metal on the substrates, one or more blocking shields are provided of a size that interfere with the deposition of sputtered material along center sections of the substrates while permitting normal deposition along the edge sections of the substrates.
BRIEF DESCRIPTION OF THE DRAWING Other advantages and features of the invention will appear from a consideration of the following detailed description when considered in conjunction with the drawings, wherein:
FIG. 1 is a perspective view of a tray or rack holding a pair of substrates to be sputtered by the apparatus of the present invention;
FIG. 2 is a schematic plan view of the overall apparatus illustrating the flow of substrates from a loadingunloading position, to an outgas position, to a sputtering position and then back to the initial position;
FIG. 3 is an enlarged sectional view, taken along line 33 of FIG. 2, particularly illustrating the substrate batch loading facilities and the facilities for transferring the substrates into a sputtering chamber;
FIG. 4 is a sectional view of the sputtering chamber depicting a duct and shield arrangement for the introduction and diffusion of gasses into the chamber and a cooling system for controlling the sputtering chamber atmosphere;
FIG. 5 is a sectional view taken along line 5-5 of FIG. 4 illustrating the arrangement of diffusion shields and blocking shields that function to provide a uniform plasmaa and a uniform deposition of sputtered material on the substrates;
FIG. 6 is a partial sectional view through the cathode illustrating further details of the ducts, ports and the diffusion shields;
FIG. 7 is a partial sectional view of a gas diffusion plug which may be used as an alternative for the shields shown in FIG. 6; and
FIG. 8 is a timing diagram showing the relative operation of the various component mechanisms.
DETAILED DESCRIPTION Substrate Trays and General Overall Facilities Referring first to FIG. 1, there is shown a tray for receiving a pair of planar substrates 21 that may be constructed of glass or other ceramic-like material. The tray is formed of channel frame members 22 for supporting the edges of the substrates. Top and bottom cross members 23 and 24 are secured to the upright frames 22. Mounted on the bottom member 24 are a pair of wheels 26 and 27 which function to assist the support of the frame for movement during a sputtering operation. Offset from the plane of the wheels is a guide plate 28.
Prior to the sputtering onto the substrates, the substrates and trays are loaded in a magazine 30 in a radial array and are prebaked in an oven to outgas these elements. Referring to FIG. 2, the trays, while mounted in the magazine 30 and still warm, are loaded into a maqazine chamber 31. The magazine chamber 31 is one of three which are supported on a yoke 32 located within a housing 33 maintained at a vacuum condition approaching that existing in a sputtering chamber 34. During the loading operation at position 31A, the magazine chamber 31 is sealed from the housing 33 and exposed to permit the loading of the magazine of substrates. Following the loading of the substrates, the magazine chamber is evacuated down to vacuum conditions which exist within the housing 33. The yoke 32 is indexed 120 to move the magazine chamber into an outgas position 31B. The magazine chamber is held in this position for a period of time while the outgassing process continues to further extract any residual gasses within the trays 20 or the substrates 21. Next, the magazine chamber is moved to a transfer position 31C where the magazine 30 is rotated intermittently to move each tray into position to be advanced into the sputtering chamber 34. Following each advance of a tray into the sputtering chamber, a tray of completely sputtered substrates is moved into the vacated space in the magazine. The trays 20 are advanced in a circular path about a cylindrical cathode positioned within the sputtering chamber 34. The advance of the substrates is accomplished by a carrousel holder 36 which is successively indexed to move each tray from the load position about the centrally disposed cathode and back to the initial position where the trays are again transferred back to the magazine. The magazine chamber is subsequently returned to the initial load position 31A where air is introduced into the magazine chamber and the magazine of trays is unloaded and replaced with a magazine of heated trays of new substrates to be coated. Machine Load and Transfer Facilities Attention is directed to FIG. 3 for consideration of the methods and apparatus for loading a magazine chamber 31 with a magazine 30 of substrates 21, advancing the magazine chambers through the outgassing position 318 and to the position 31C for transferring the substrates into the sputtering chamber 34. Each magazine chamber 31 comprises a tub-like chamber or drum 41 of stainless steel having a centrally disposed bearing block 42 secured to the bottom of the chamber. Mounted within the bearing block is a flanged shaft 43 on which is mounted a removeable magazine 30. The magazine comprises a plurality of radially extending U-shaped frames 44 having upright channels for receiving the trays 20. The shaft 43 has a shoulder 45 for supporting the magazines 30. The radial arrangement of the frames 44 locates the trays of substrates in substantially back to face relation. This arrangement together with the reflective inner surfaces of the stainless steel chamber 41 insures the retention of the prebake heat in the substrates to provide for the further outgassing of the trays and the substrates. Slidably mounted within the shaft 43 is a lock rod 46. A drive flange 47 is secured to the lower end of the shaft 43 and has a plurality of circumferentially spaced bores 48 to receive drive studs 49 projecting from a hub 50 on a spline shaft 51 rotated by a solenoid controlled indexing drive unit 52. The lock rod 46 has a cross pin 53 extending through longtitudinal slots formed in the shaft 43 and resting within an opposed pair of a group of lock slots 54 formed about the upper surface of the bearing block 42. The upper end of the rod 46 is engaged and urged downwardly by a compression spring 55. The upper section of the rod 46 has a tapered shoulder 59 which is engaged by a series of three radially disposed spring loaded lock plungers 56 (only one is shown), for locking the magazine to the shaft 43.
In the sputtering chamber transfer position 31C, an air cylinder 57 is operated to elevate the spline shaft and the hub 50 to move the studs 49 into the bores 48. When the hub 50 is elevated, a centrally located push pin 58 engages and pushes the lock rod 46 upwardly to move the cross pin 53 from the slots 54 thus freeing the shaft 43 for rotation. The tapered shoulder of rod 46 acts against the spring loaded plunger 56 to force the plunger into locking engagement with the magazine 30. The spline shaft 51 is incrementally rotated to rotate the hub 50, the flanged shaft 43 and the magazine 30 to index the frames 44 into position so that the trays may be advanced into the chamber 34. When the indexing of the frames 44 is completed, the hub 50 is withdrawn and the cross pin 53 is again urged by spring 55 and positioned in a pair of slots 54 to lock the shaft 43 and the magazine channel frames 44 from movement while the magazine chamber 31 is moved to the unload position 31A.
The bottom of the magazine chamber 31 is also pr0- vided with a series of circumferential spaced apertures 61 which are indexed into position so that a pusher rod 62 may pass cyclically therethrough to advance each tray 20 into the sputtering chamber 34.
Considering the loading of a magazine 30 of substrates into the magazine chamber 31 at load position 31A, it will be noted that the magazine chamber has a band 66 girthing its midsection. This band rests on the edges of an arm 67 of the yoke 32. When a magazine chamber 31 is in the load position, a dished out plate 68 is advanced by an air cylinder 69 to engage the underside of the magazine chamber. The plate is provided with an O-ring seal 71, which engages the underside of the magazine chamber and seals the apertures 61 from the vacuum within the housing 33. The advance of the plate 68 moves the magazine chamber upwardly so that the top flange section engages an O-ring seal 72 mounted within a recess formed about a depending lip of an entry cylinder 73 that extends through an opening in the housing 33. The upper end of the cylinder 73 is sealed by a heavy metallic lid 74. With the magazine chamber 31 in its elevated position, air or a dry gas is introduced into a port 76 to normalize the pressure within the magazine chamber to that of the ambient atmosphere. The lid 74 is lifted and a pre-loaded magazine 30 of trays 20 is placed into magazine chamber. Upon completion of the loading operation, the lid 74 is replaced. Next, the air supply to the port 76 is interrupted and vacuum is drawn through the port 76. This vacuum may be initially established by a mechanical pump and then brought to a more finite value by use of a diffusion pump. When the vacuum is re-established in the magazine chamber 31, the plate 68 is lowered and the magazine chamber is again supported on the arm 67 of the yoke 32.
The yoke 32 is secured to a shaft 77 rotatably mounted with suitable seals and hearings in the lower section of the housing 33. The shaft 77 is driven by a bevel gear 78 which, in turn, receives motion from suitable solenoid controlled indexing unit (not shown) to index the shaft 77 and the yoke 32. The solenoid controlled drive unit is actuated following each complete loading of a magazine chamber 31 with a magazine of film-coated substrates and is effective to index the yoke through 120. During each rotation of the shaft 77, a magazine chamber loaded with uncoated substrates is moved to the outgas position 31B (see FIG. 2). Inasmuch as there is a vacuum being continually maintained within the housing 33 and the temperature within the housing is hotter than the ambient atmosphere, the preheated substrates will be further outgassed prior to loading into the sputtering chamber. Loading Facilities for Sputtering Chamber Referring first to FIG. 3, the yoke 32 indexes each magazine chamber 31 into position 31C to have the substrates moved into the sputtering chamber 34. Following advance of the magazine chamber 31, the air cylinder 57 is operated to advance the driving studs into the holes 48 formed in the driving plate 47. The solenoid controlled indexing unit 52 is actuated to rotate a belt 78 to cyclically impart motion to a sprocket 79 on the spline gear 51 which, in turn, rotates the spline gear 51, the hub 50, the flanged shaft 43 and the magazine 30 to index each tray 20 into an alignment with a slot 146 formed in the housing 33. As each tray is positioned in alignment with the slot 146, the push rod 62 with a roller 80 mounted thereon is advanced so that the roller engages the plate 28 of the tray. The push rod 62 is advanced by a commercially available ball-nut and screw arrangement 81 which is again driven by a solenoid controlled drive unit 82. The tray moves through the slot in the housing 33, along guides 83 and then between a pair of lateral supports or guide rails 84 until the top member 23 of the tray 20 is clipped by a pair of a group of spring clips 85 depending from a top frame member 86 of the carrousel holder generally designated by the reference numberal 36. The carrousel includes a bottom frame member 89 (see FIG. 4) se cured to a hub 91 attached to a drive shaft 92 which is cyclically indexed by suitable solenoid controlled driving unit 93. The bottom frame member 89 is electrically isolated from the remainder of the carrousel holder 36 by interposed insulator pillars 95 on which the main portions of the carrousel holder are sup ported.
When the pushrod 62 advances a tray 20 into the sputtering chamber 34, the roller 80 supports the tray on the plate28. Actually the spring clips 85 are strong enough to hold the tray, but to insure stability of the trays during the indexing through the sputtering chambet, the wheeled tray 20 moves on a rail 101 (see both FIGS. 3 and 4). Upon indexing of the carrousel 36, the wheel 26 rides onto the rail 101 wlhile the plate 28 rides on the roller 80. Following movement of the wheel 27 onto the rail 101, a tray of film-coated substrates is positioned to be supported on the roller 80.
Sputtering Chamber Attention is directed to FIGS. 4 and 5 for a consideration of the details of construction of the sputtering chamber. The chamber comprises an outer hollow cylinder 102 supported between a top plate 103 and a bottom plate 104, which is mounted on and sealed to the top of the housing 33. The cylinder 102 is constructed of aluminum and the inner surface is anodized to facilitate the absorption of heat. Wrapped around the outer periphery of the cylinder 102 are spiral convolutions of a tube or rod 106. A drum 107 is placed over the convolutions so that a spiral passageway is defined between the convolutions and the outer surface of the cylinder 102 and the inner wall of the drum 107. Water is circulated through this spiral passageway to further aid in the dissipation of heat. Mounted within the cylinder 102, and secured to the top plate 103, is a second or inner coaxially positioned cylinder 108, also constructed of aluminum. This cylinder is provided with a circumferential duct 109 interconnecting ducts 111 and 112, which extend longitudinally away from the duct 109. Duct 109 is connected by way of tubing 113 to a source of inert gas or a mixture of inert gas and a reactive gas, such as a mixture of argon and nitrogen. The gas is distributed through the ducts and is emitted through a series of ports 114. The ports 114 are aligned with passageways 116 formed in a cylindrical cathode 117, constructed of tantalum or some other metal that is to be sputtered onto the substrates. Looking at FIGS. and 6, it will be noted that the passageways 116 are aligned with a series of strip shields 118 that extend longitudinally of the cathode and may be constructed of the same material as that of the cathode and electrically connected to the cathode so as to act as constituent parts of the cathode. Gas emanating from the ports 114 and the passageways 116 strikes the shields 118 and is diffused over the adjacent surfaces of the cathode 117.
In order to control the heat, the inside of the cylinder 108 is cooled by water. Water is admitted through a tube 121 and impinges in a well 122, then rises, and is exited out by exhaust tubing arrangement 123.
It will be noted that the cylinder 108 is provided with O-ring seals 131 and 132 to preclude the passage of water into the sputtering area. While the outer cylinder 102 is also provided with O ring seals 133 and 134 to preclude the entry of ambient atmosphere. Considering seal 131 as being typical, the top plate 103 is cut out to receive the upper section of the inner cylinder 108, which is also cut out. The cutout in cylinder 108 receives the seal 131 and the weight of the plate 103 acts to compress the seal. Water inside the cylinder 108 must pass contact lines of engagement 131a and b or lines 131a and d before the water can enter the sputtering area. In other words, the compression of the O-ring seals, both in the horizontal and vertical directions, provides two lines of contact that must be passed before a fluid can pass the seal.
Looking at FIG. 5, it will be noted that a tray of substrates 21, mounted between adjacent carrousel guide rails 84, is positioned between adjacent shields 118 during a sputtering operation. Due to the planar construction of the substrate, the center area of the substrate is closer to the cylindrical surface of the centrally located cathode and, hence, normally would receive a greater deposit of sputtered material. In order to compensate for this factor and insure a uniform deposition of sputtered material, a pair of partially blocking shields 136 and 137 are positioned in the sputtering area to intercept the sputtered material at two locations during the time each substrate is in the sputtering chamber. The shield 136 is formed as a right-angle piece to preclude warping due to the heat generated by the sputtering operation. The shielding effect provided by shield 136 is such that the edge sections of the substrates 21 are fully exposed to the normal sputtering action. It should be noted also that the strip shields 118 project towards the same edge sections and inasmuch as these shields can act as part of the cathode, there is an increased amount of material sputtered onto the edge sections. The overall effect is that the sputtered material is uniformly deposited on the substrates exiting from the sputtering chamber.
When the carrousel 36 advances in a circular path about the coaxially located hollow sputtering cathode and a film coated substrate is moved into alignment with the exit slot, an upper pushrod 141 is operated by a mechanism 142, similar to the mechanism used to advance the pushrod 62, so as to push the tray downwardly from the spring clips 85 against the still elevated pushrod 62. The pushrods 141 and 62 now move in unison to move the tray back into the magazine 30. When the magazine is completely loaded with film-coated substrates, the solenoid controlled indexing mechanism for the yoke 33 is again operated to advance the magazine chamber 31 back to the original position 31A. Following admission of air into the magazine chamber 31, the lid 74 is lifted and the magazine of trays of filmcoated substrates may be removed and a magazine of trays of uncoated substrates loaded into the magazine chamber.
The operation of the various solenoid controlled drive units and the air cylinders may be sequentially controlled by a cam-operated controller in the sequence depicted in timing diagram of FIG. 8. In the alternative, the operation of the various component mechanisms may be controlled by a series of limit switches and an electrical control circuit. The particular means of sequence control may take other forms so long as the various handling and process steps are accomplished in the sequence described.
Referring to FIG. 7, there is shown an alternative arrangement for diffusing the inert gas over the cathode.
The shields 118 are replaced by a series of plugs 151 seated within openings 116 in the cathode 117. The plugs each have a blind bore 152 and a pair of slots 153 exposing the bore to the gas emanating from the aligned port 114. It will be noted that the seated end of the plug is exposed to the relatively cool inner cylinder 108. The projecting plugs act as part of the cathode and are positioned closer to the edges of the substrates between indexing of the carrousel so as to insure a more uniform deposition of metal on the substrate.
Cycle of Operation At load position 31A, with the lid 74 removed, a prebaked magazine 30 (FIGS. 2 & 3) of still warm trays of substrates 21 is loaded in the magazine chamber 31. When the magazine chamber 31 is loaded, the lid 74 is replaced and vacuum drawn through the port 76. The elevator plate 68 is lowered to move the magazine chamber back onto the yoke 32. Yoke 32 is then indexed to the outgas position 313 and held there while one of the other magazine chambers 31 is being unloaded and loaded and the other magazine chamber is being utilized to supply and receive substrates to and from the sputtering chamber 34. Upon the next advance of the yoke 33, the outgassed magazine of substrates is positioned for loading into the sputtering chamber 34. The hub 50 and flange 47 coupling is established by actuation of air cylinder 57 so that the magazine 30 may be subsequently indexed. The pushrod 62 is actuated to advance the first aligned tray through aligned slots 146 and 147 formed in the top of the housing 33 and the bottom plate 104 of the sputtering chamber into the carrousel holder 36. These aligned slots are substantially tangent to the circular path of movement of the trays in the sputtering chamber. The carrousel holder 36 is then indexed and the loaded tray is moved so that the wheels 26 and 27 ride onto the rail 101. The trays 20 are held by the spring clips 85, and wheels 26 and 27 riding on the rail 101 insure stable positioning of the substrates during the sputtering operation. High voltage is applied through connector 151 while the inner cylinder 108 and the carrousel holder 36 are maintained at ground potential.
The carrousel holder 36 is indexed to move the trays 20 in a circular path about the coaxially located cath ode 117. The cathode strip shields 118 together with the blocking shields 136 and 137 cooperate to insure that the edges of the substrates 20 receive deposited metal in the same amounts as is deposited on the center sections of the substrates.
The movement of the carrousel holder 36 positions a coated tray of substrates over the aligned slots 146 and 147 so that the plate 28 rides on the roller 80 of the still elevated pushrod 62. The pushrods 141 and 62 now worlt in unison to lower the tray 20 into the magazine 30. The magazine 30 is indexed one position by movement transmitted through the now engaged coupling provided by lugs 49 on hub 50 engaging within the holes 48 formed in flange 47. This cyclic operation continues until the magazine 30 is fully loaded with coated substrates. Next, the yoke 33 is again moved to position the magazine chamber beneath the lid 74 for subsequent unloading and reloading of magazines.
When the apparatus is used to deposit a film of beta tantalum, the gas introduced into the sputtering chamber is argon. If the beta tantalum film is to be used for the fabrication of an oxide dielectric of a capacitor, then a relatively thick film e.g., 5,000A must be deposited at a slower rate. This is easily accomplished by the present machine by merely slowing down the rate of indexing of the various component mechanisms. When the deposit is to be a film of tantalum nitride for subsequent fabrication of resistor elements, the gas introduced into the sputtering chamber is a mixture of argon and nitrogen. In this instance, it is necessary to maintain heat in the substrates so as to produce resistors with a low temperature coefficient of resistance. This heating may be accomplished by mounting a thin reflective sheet of stainless steel behind each substrate mounted in a holder 20.
It is to be understood that the selection of mechanisms and component parts are merely illustrative of one embodiment of the invention and that other changes and modifications can be made without departing from the invention. The component units may be rearranged so that the yoke 32 advances the magazine chamber 31 relative to the top of the sputtering chamber 34 rather than the bottom of the chamber. In this instance, the mechanisms will be reversed, and the trays will be pushed down instead of up to load the carrousel holder 36.
What is claimed is:
1. In an apparatus for sputtering a metallic film onto substrates:
a sputtering chamber having a centrally disposed cathode for sputtering a film of the material of the cathode on the substrates;
a carrousel for holding a circular array of substrates about said cathode;
means for indexing the carrousel to move the substrates in a circular path about the cathode;
said chamber having a slot formed therein in tangential relation to the circular path of movement of the substrates;
a magazine carrier for holding a radial array of substrates;
means for intermittently rotating said magazine carrier to move each substrate into alignment with said slot;
means for moving an aligned substrate through said slot into said carrousel following each intermittent rotation of said magazine carrier and then for removing a film coated substrate from the carrousel and returning the substrate to the magazine carrier; and
means including a housing surrounding said magazine carrier for maintaining a vacuum about the substrates during movement to and from the sputtering chamber.
2. In an apparatus for sputtering metal onto substrates:
a cylindrical sputtering chamber;
a cylindrical sputtering cathode positioned axially within said chamber;
a carrousel rotatably mounted within said chamber for supporting a number of substrates in chordal relation with respect to said cylindrical chamber and spaced from said sputtering cathode;
means for cylically moving said. carrousel about said sputtering cathode;
means for applying energy across the space between the substrates and said cathode to sputter the material of the cathode onto the substrates; and
a pair of shields interposed between the substrates and said cathode for blocking the sputtered mate rial from the central portions of a pair of spaced substrates while allowing the sputtered material to deposit on opposed edge sections of the substrates.
3. In an apparatus for sputtering metal onto falt substrates:
a magazine carrier having means for supporting a mass of substrates with their major planes arranged in a radial array;
a sputtering chamber having a circular trackway for supporting substrates to move in a circular path; said sputtering chamber having an entry port to said trackway;
means for rotating said magazine carrier to move each substrate into alignment: with said entry port;
means for moving the aligned substrate into said sputtering chamber, upon advance of each substrate into alignment with said entry port, with its major plane facing the center of the circular path;
means for advancing each substrate moved into said chamber along said trackway; and
means for radially sputtering from the center of the path onto the substrates.
4. In an apparatus for sputtering metal onto a substrate as defined in claim 3:
means for removing each substrate from the circular path upon completion of movement along the path to a position at said entry port and restoring the substrate into the radial array on said magazine carrier.
5. In a sputtering apparatus:
a sputtering chamber having a hollow cylindrical cathode of a material to be sputtered; said cathode having longitudinal rows of openings extending therethrough;
a hollow aluminum cylinder coaxially positioned within said cathode, having a circumferentially extending duct with longitudinally extending ducts exiting in a number of ports in the surface of said cylinder and in alignment with the openings in said cathode;
strip-like shields spaced from and overlaying the longitudinal rows of openings in the cathode;
means for maintaining a vacuum in said sputtering chamber;
means for introducing an ionizable inert gas through said ducts and through said openings to diffuse the gas against the shields;
means for positioning a plurality of substrates about the cathode;
means for applying a voltage to said cathode to dislodge and sputter atoms of the material of the cathode onto substrates; and
means for moving substrates into and out of the positioning means under vacuum.
6. In a sputtering apparatus as defined in claim a plurality of blocking shields each of which is positioned between a pair of said strip-like shields to interfere with the deposition of the sputtered material on center sections of aligned substrates; and wherein the blocking shields are separated from each other by more than the distance between adjacent strip-like shields; and means for moving the positioned substrates about a circular path which is coaxial with respect to the cathode.
7. In a sputtering apparatus as defined in claim 6:
wherein said shields are constructed of the same material as said cathode; and
means are provided for connecting said strip shield to said cathode to sputter the material of said shield.
8. An apparatus for sputtering metal onto substrates,
a sputtering chamber having a centrally located cath ode;
a housing having a first opening in communication with said sputtering chamber and second opening in communication with the ambient atmosphere;
a lid removably positioned over said second opening;
means for maintaining a vacuum in said housing;
a plurality of substrate magazine carriers having enclosing walls and a loading opening in one end; means for mounting said carrier for movement to and from positions in alignment with said first and second openings in said housing and for movement toward said aligned second opening;
means for moving said carrier positioned in alignment with said second opening toward said second opening to move said loading opening of said magazine carrier into sealing engagement with said housing about said second opening whereby said lid may be lifted and said carrier loaded with substrates;
means for pumping down the substrate loaded carrier when said lid is replaced to establish a vacuum about the substrates;
cyclically operated means for moving the substrates from said magazine carrier in alignment with said first opening into said sputtering chamber; and
means for moving the substrates in a circular path in said sputtering chamber about said cathode.
9. An apparatus for coating articles in a controlled atmosphere that has characteristics different from the ambient atmosphere, which comprises:
a carrousel mounted for rotation;
a plurality of trays for retaining articles therein:
clips for retaining trays in said carrousel;
wheels on said trays;
guide rails for supporting said trays in said carrousel, said wheels engaging said rails to roll along said rails as the carrousel rotates;
means for sputter coating material from within the carrousel onto the articles;
feed means for removing trays having coated articles therein from the carrousel and for moving trays having uncoated articles therein into the carrousel; and
means for maintaining the controlled atmosphere about the carrousel and said feed means.
10. An apparatus as defined in claim 9, wherein said coating means includes sputtering facilities comprising a cylindrical cathode.
11. An apparatus as defined in claim 9, wherein the said feed means includes a first push rod, and means for moving the push rod to remove a coated article from the carrousel; and a second push rod, and means for moving the second push rod to move uncoated articles into the carrousel.
12. An apparatus as defined in claim 9, wherein said atmosphere maintaining means includes a chamber about the carrousel and a housing about the feed means for maintaining a vacuum about the trays being removed from and moved into the carrousel and about the trays moving with the carrousel.
13. An apparatus as defined in claim 12, wherein said coating means includes a hollow, cylindrical cathode with a plurality of passageways extending therethrough;
means for injecting an inert gas through said passageways;
means for diffusing the gas across the cylindrical surface of said cathode; and
means for applying energy to said cathode to sputter the material of the cathode onto the procession of articles.
14. In an apparatus for sputtering metal onto sub strates:
a sputtering chamber having an entry opening for passage therethrough of substrates;
a plurality of open-ended carrier chambers for re-.
ceiving and rotatably mounting magazines of substrates;
yoke means for supporting said carrier chambers for movement about an axis of said yoke means and for movement longitudinally of said axis;
a housing surrounding said carrier chambers and said yoke means, and said housing having a first opening communicating with said entry opening and a second opening for loading a magazine of substrates;
a removable lid covering said second loading opening in said housing;
means for indexing said yoke means and said carrier chambers to position a first of said carrier chambers with its open end in register with said entry opening and a second of said carrier chambers with its open end in register with said second loading opening;
means for moving said first carrier chamber longitudinally of the axis of said yoke means, upon indexing of said yoke means, to move the open end of said first carrier chamber over said loading opening whereby the lid may be removed to load a magazine of substrates;
means for incrementally rotating said magazine in said second carrier chamber upon indexing of said yoke means; and
means for advancing a substrate from the magazine through the open end of said carrier chamber, the opening in said sputtering chamber and into said sputtering chamber, upon each incremental rotation of said magazine.