US3238918A

US3238918A - Vacuum deposition chamber for multiple operations

Info

Publication number: US3238918A
Application number: US161927A
Authority: US
Inventors: Richard P Radke; William E Blair
Original assignee: Lear Siegler Inc
Current assignee: Lear Siegler Inc
Priority date: 1961-12-26
Filing date: 1961-12-26
Publication date: 1966-03-08
Anticipated expiration: 1983-03-08

Description

8, 1966 R. P. RADKE ETAL 3,238,918

VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS Filed Dec. 26, 1961 8 Sheets-Sheet l FlG.l

l6 INVENTOR.

- RICHARD P.RADKE WILLIAM E. BLAlR AGENT March 8, 1966 R. P. RADKE ETAL 3,238,913

VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS Filed Dec. 26, 1961 8 Sheets-Sheet 2 FIG.2

INVENTOR. RICHARD P. RADKE yWILLlAM E.BLA|R AGENT 1 an-ch 8, 1966 R. P. RADKE ETAL VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS Filed Dec. 26, 1961 8 Sheets-Sheet 5 INVENTOR. C D P. RA DKE Y I L l A M E B LAI R AG E N T Mam}! 1966 R. P. RADKE ETAL 3,238,913

VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS Filed Dec. 26, 1961 8 Sheets-Sheet 4 FIG.4

INVENTOR. w RICHARD P. RADKE WILLIAM E. BLAIR www- AGENT March 1966 R. P. RADKE ETAL 3,233,913

VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS Filed Dec. 26. 1961 8 Sheets-Sheet 5 IN VEN TOR.

RICHARD P. RADKE WILLIAM E. BLAIR MF/WM AGENT March 8, 1966 R. P. RADKE ETAL VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS 8 Sheets-Sheet 6 Filed Dec. 26, 1961 A GE N T March 8, 1966 R. P. RADKE ETAL 3,238,913

VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS Filed Dec. 26, 1961 8 Sheets-Sheet 7 FlG. 8

INVENTOR. RICHARD P. RADKE WILLIAM E.BLA|R WAX 2% AGENT 166 R. P. RADKE ETAL 3,238,918

VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS Filed Dec. 26, 1961 8 Sheets-Sheet 8 RICHARD P. RADKE WILLIAM E. BLAlR gs /fwz United States Patent 3,238,918 VACUUM DEPOSITION CHAMBER FOR MULTIPLE OPERATIONS Richard P. Radke, Northridge, and William E. Blair, Redondo Beach, Calif., assignors to Lear, Sicgler Inc., Santa Monica, alii., a corporation of Delaware Filed Dec. 26, 1961, Ser. No. 161,927 8 Claims. (Cl. 118-491) This invention relates to means of evaporating material onto a substrate and more particularly, to means to mass produce substrate having evaporated material thereon in a desired pattern.

Vacuum depositions and sputtering are accomplished in a vacuum chamber. The material to be vacuum deposited or sputtered is placed near a heating element or filament, and a substrate on which the material is to be evaporated, is positioned some distance from the material to be evaporated. A mask is positioned between the material to be evaporated and the substrate so that the evaporated material passes through the mask and condenses on the substrate in the pattern of the mask. This allows, for example, a resistive element to be evaporated or sputtered on a substrate in a zig zag pattern to control the resistance of the element, i.e., the resistance of the element is dependent upon the material chosen, the thickness of the evaporated layer put on the substrate, and the length of the line of material put on the substrate. Because this work is done in a vacuum chamber, once the operation is started there is virtually no mechanical access to the equipment inside the vacuum chamber. In order to get the proper vacuum, a considerable amount of time is required for pump down, while the chamber is being evacuated. Since the past methods used only accommodated one substrate, or at best a few substrates and one mask, the greatest cost in making the microcircuits was in the pump down time and also the cooling time after the circuits had been deposited. The pump down time and the cooling time might be approximately two hours as opposed to twenty or thirty seconds deposition time.

It is, therefore, an object of this invention to provide a mechanism for a vacuum chamber which will permit the deposition of a plurality of microcircuits on several substrates.

Another object of the present invention is to provide a mechanism for a vacuum chamber which permits the vacuum deposition of different components of microcircuits during one pump down of the chamber.

Still another object of the present invention is to provide a mechanism for a vacuum chamber which will allow the vapor deposition of several elements onto a given substrate through the use of a plurality of sources of material to be evaporated and a plurality of masks to be used between the sources of material to be evaporated and the substrate.

Other objects and advantages of the present invention will become apparent from the following description when taken in conjunction with the drawings, in which:

FIG. 1 is a perspective view of a vacuum chamber;

FIG. 2 is a perspective view of the inside of a vacuum chamber;

FIG. 3 is a top view of the present invention;

FIG. 4 is a plan view of a mask holder;

FIG. 5 is a cross-sectional view of the mask holder and substrate holder;

FIG. 6 is a plan view of the rotating mechanism;

FIG. 7 is a view taken along lines 77 in FIG. 6;

FIG. 8 is a perspective view of the heater element; and

FIG. 9 is a schematic diagram of the control of the present invention.

Referring to FIG. 1, there is shown a vacuum chamber 10 having a base portion 11, a cover portion 12, and a viewing chamber 13. The viewing chamber 13 has a glass or transparent surface 14 to allow the inside of the vacuum chamber to be viewed from the outside. The cover portion 12 is mechanically connected to the arm 15, which in turn is mechanically connected to a screw jack, not shown. The screw jack raises and lowers the cover 12 for access to the vacuum chamber. The lever arm 16 is mechanically connected to the substrate holder, and its operation will be described below.

The inside of the vacuum chamber is shown in FIG. 2. A substrate holder 20 is mechanically connected to the lever arm 16 shown in FIG. 1 through a mechanical vacuum seal in the base of the vacuum chamber. The substrate holder 20 has slots 21 therein to accommodate substrates. The substrates can be the standard variety of glass or any suitable non-conductor. A mask holder support 22

supports mask holders

23, 24, and 25. The masks used also are the standard type made from a thin metal with a desired pattern cut in the metal. The substrate holder, mask holders, and mask support will be described in greater detail below.

Housings

26 and 27 have inside thereof heater elements and sources of material to be evaporated. A third housing, similar to housing 27, is shown in FIG. 3 and will be described below.

The heating elements and their connection with the source of material to be evaporated are well known in the art and any particular combination of heating elements and material can be used. A typical heater element is shaped like a trough and the material to be evaporated is placed in the trough. The housing 27 has one shutter mechanically operated by solenoid switch 28 by way of the

mechanical connections

29, 30 and 31. The shutter is not shown but is positioned between the housing 27 and the duct 32. Three

ducts

33, 34 and 35 are positioned above the housing 26. The housing 26 has three shutters, not shown, one for each duct and each actuated by a solenoid similar to solenoid 28.

Tubes

36 and 37 originate at the viewing chamber 13 and extend into the larger vacuum chamber using a series of mirrors so that the process of vacuum deposition may be viewed through the viewing chamber 13. Mirror 33 is shown positioned to view the underside of mask holder 25. The duct 32 is cut out to allow the viewing.

The

conduits

33, 34, 35 and 32 provide a conduit sheathing means through which vaporized material is deposited on substrates at different angles of incidence, as shown in FIGS. 2 and 3.

Conduits

33, 34 and 35 conduct vapors from a single source in housing 26. The vapors can be conducted through one, two or three of the

conduits

33, 34 and 35 at the same time depending on whether the individual shutters in these conduits are open or closed. The deposition made on a substrate through conduit 34 is at a first angle of incidence of substantially The vapors passing through conduit 33 are deposited on a substrate at a second angle of incidence which is greater than 90 when measured counterclockwise for a clockwise rotation of the substrate supporting means or holder 20. Conduit 35 permits for the deposition of vapors on a substrate at a third angle of incidence which is less than 90. In this construction, the third angle of incidence is smaller than 90 by an amount which is substantially the same as the second angle of incidence is greater than 90. The vapors coming from source in housing 27 and passing through conduit 32, are deposited at an angle of incidence which is less than 90 but greater than the third angle of incidence. The purpose of the deposition at diiferent angles is to prevent the deposition of a film layer from being deposited through a pin hole or other imperfection in a previously deposited film and thus causing a short circuit with a second underlying layer.

Generally, the operation is that a separate substrate is positioned in each of the slots 21 in the substrate holder 20. A separate mask is positioned on each of the

mask holders

23, 24 and 25. The chamber is evacuated through port 39 by use of a standard vacuum pump connected to port 39. The material in the

housings

26 and 27 are then heated to the evaporation point and the proper shutter is opened allowing the evaporated material to pass through the mask onto the substrate. When the evaporation is complete, the shutter is closed. Each substrate is passed over each mask so as to have a completed circuit when each substrate has been over each of the masks and had the material evaporated onto it through each of the masks.

Referring to FIG. 3, the third housing 40 and shutter 41 are shown with the shutter 41 over the opening to chamber 40. The shutters over

chambers

26 and 27 are not shown because of the angles of the

ducts

32, 33, 34 and 35. It can be seen from FIG. 3 that When the solenoid which moves shutter 41 is actuated, the opening to the chamber 40 is in direct connection to duct 42. Therefore, any material which is heated in the chamber 40 to the state of evaporation, evaporates up through the duct 42 through the mask and onto the substrate. Leads 43 and 44 are positioned on the substrate holder and pass down to the monitor substrate (not shown) used for monitoring the amount of evaporation. The connection of the

leads

43 and 44 to the outside of the vacuum chamber will be described below.

FIG. 4 shows the lead 44 contacting the monitor slide 45. One end of the monitor slide 45 is connected to ground and the other end of the monitor slide 45 is connected to the lead 44. The monitor slide is painted with a conducting paint, or otherwise provided with an electrical connection with one end of the underside of the monitor slide 45 to lead 44. The other end of the underside of monitor slide 45 is grounded. It can be seen, then, that prior to evaporation, there is an open circuit between the two ends of the monitor slide 45. It is to be noted that the mask allows only a hair line to be evaporated onto monitor slide 45. This is so that when the substrate and monitor slide are moved to another mask, the new mask allows another hair line to be deposited and monitored by the other lead 43. As the evaporation progresses, the resistance between one end of the slide 45 and the other end of the slide 45 decreases as the material is evaporated. This provides a means for monitoring the amount of material to be evaporated onto the substrate 46. Only one lead 44 is shown, but lead 43 shown in FIG. 3 is used to monitor the monitor slide 45 in conjunction with a different mask as stated above.

FIG. is a view taken along lines 55 of FIG. 4 and shows the mask holder 50 supported by the mask holder support 22. The mask holder 50 is held to the support 22 by way of

screws

51 and 52. It is to be noted that the

screws

51 and 52 are securely fastened to the mask holder 50 but have considerable play in the support 22.

Springs

53 and 54 urge the mask holder 50 away from support 22. Mask 55 is indexed on mask holder 50 by the indexing pin 56. The mask 55 has the desired pattern for the circuit to be evaporated through that mask. The plate 57 is secured to the substrate holder 20 and holds the substrate 46 and substrate monitor 45. When the substrate holder 20 is lowered into position, the indexing pin 56 registers with an indexing hole 58 in the plate 57. Consequently, the substrate 46 maintains its position in the substrate holder 20 while the indexing pin 56 causes the mask held by the mask holder 50 to make the proper registration against the bottom of the plate 57.

Pins

59 and 60 make contact with the

leads

43 and 44, respectively. The electrical connection to

pins

59 and 60 will be described below.

Referring to FIGS. 6 and 7, the shaft 70 is mechanically connected to disk 71. Disk 71 has a series of holes 72. Shaft 70 is mechanically connected to the substrate holder 20. The lever arm support 73 is rotatable with respect to shaft 70. The lever arm support 73 has a pin 74 extending therefrom and registerable with the hole 72. Stationary support 75 has a pin 76 extending therefrom and also registerable with the hole 72. The lever arm 16 extends from the arm holder 73 and is movable about the pin 78 through both the support 73 and the lever arm 16. A chain gear 79 is mechanically connected to the disk 71 and an indicator -80 rotatable about shaft 81 has another chain gear 82 mechanically attached thereto and a chain 83 is mechanically connected to the chain gear 79 and chain gear 82.

In operation, the lever arm 16 is raised so that the pin 74 registers with one of the holes 72. This is caused by the lever arm 16 hitting the bolt 83 and thereby raising plate 71 with respect to pin 76. Next, the lever arm 16 is moved laterally which, in turn, causes the plate 71 and shaft 70 to rotate, thereby causing the substrate holder 20 to rotate also. When the rotation is complete, the lever arm 16 is dropped and the plate 71 lowers with the pin 76 registering with a new 'hole 72. The chain gear 79 being mechanically connected to the plate 71, rotates with the plate 71 causing the indicator 80 to rotate, thereby giving the operator a visual indication of the position of substrate holder 20. It should be noted that the shaft 70 is the only movable mechanical connection through the vacuum chamber base. The opening which allows shaft 70 to pass through the base of the vacuum chamber is vacuum sealed in the normal manner.

It is desirable to have the substrates heated at the time the material is deposited on the substrate. As shown in FIG. 8, a plurality of heater wires are connected in parallel between two

electrode connections

91 and 92. The heater wires 90 are supported by and insulated from a reflector shield 93. The reflector shield, in turn, is mechanically supported by the cover 12. When the cover 12 is lowered to close the chamber 10, the heater wires 90 are directly above the substrates, thereby providing the heat for the substrates.

FIG. 9 shows a typical electrical connection to the present invention. A variable power supply is directly connected to and provides the power for the heater wires 90. A similar variable power supply 101 is electrically connected to and provides the power supply for the heater element 102. The heater element 102 is a typical heater element which may be in, for example, housing 27. A solenoid switch, for example, solenoid which 28 is electrically connected to the battery 103 either by way of switch 104 or switch 105. Switch 105 is a manual switch allowing the opening and closing of the shutter by the solenoid 28 by manual operation. Switch 104 is mechanically operated by relay 106. Relay 106 is electrically connected to the output of the bridge circuit 107. The input to the bridge circuit 107 is electrically connected to the regulated power supply 108 by way of switch 109. A variable resistor 110 forms one leg of the bridge 107 and the slide to be monitored connected by way of either

59 or 60 forms another leg of bridge 107. Resistors 111 and 112 form the two remaining legs of the bridge circuit 107 and are equal in value.

In operation, first, if it is desired to manually operate the system, the heater element 90 is fed by variable power supply 100 and the filament 102 is powered by the variable power supply 101. When the filament 102 brings the material (not shown) up to the vaporizing point, switch 105 is closed, thereby actuating solenoid 28 to open the shutter and allow the vaporized material to deposit on the heated substrate. Note that in the manual operation, switch 109 is open; therefore, switch 104 is open and solenoid 28 is operated solely by the manual switch 105. For automatic operation, however, switch 109 is closed and switch 105 is open. Since switch 109 is closed, and

at the start of the operation, the filament 102 has not had time to evaporate the material, then the electrical connection between one side of the monitor slide connected to point 60 and the other side of monitor slide connected to ground is effectively an open circuit. Therefore, the power from regulated power supply 108 goes to the bridge circuit 107, which is unbalanced, thereby causing a current flow in the relay 106, and in turn closing the switch 104. However, when the filament 102 has heated the material to be evaporated sufiiciently to cause enough evaporated material to be deposited on the monitor slide, the resistance between the two ends of the monitor slide approaches the resistance set on the variable resistor 1110 thereby balancing the bridge circuit 107 and causing the relay 106 to be de-energized, opening switch 104. Note that resistor 110- is a variable resistor and can be set to any desired resistance value, which, when such resistance value is reached between the ends of the monitor slide, indicates that the proper amount of material has been deposited through the mask onto the substrate.

The apparatus of this invention has been used successfully to vapor deposit microcircuits onto a substrate in a desired pattern and with given values for each of the components deposited.

Although this invention has been particularly described above, it is not intended that it should be limited by the above description, but only in accordance with the spirit and scope of the appended claims.

What we claim is:

1. In a vacuum chamber having means to evacuate gases therefrom, the combination comprising:

(a) a vertically movable substrate supporting means,

rotatably mounted in said chamber, for supporting a plurality of substrates in a horizontally disposed plane;

(b) a plurality of material evaporation source housings mounted in said chamber below said substrate supporting means;

(c) evaporating means in said housings;

(d) a pattern mask supporting means, mounted intermediate said evaporation source housings and said substrate supporting means, for supporting a plurality of masks in a plane substantially parallel to the plane in which said substrates are supported;

(e) a plurality of shutters mounted intermediate said source housings and said mask supporting means and operable to be positioned so as to prevent vapors from selected sources from being deposited on predetermined substrates held in said substrate supporting means at a given rotary position of said substrate supporting means;

(f) conduit sheathing means extending from said sources toward said mask supporting means wherethrough vapors of materials from the sources in said evaporation source housings are deposited on a predetermined substrate which is at a preselected position at a plurality of different predetermined angles of incidence.

2. The combination of claim 1 and in addition a heating means mounted above said substrate mounting means to provide heat for said substrates.

3. The combination of claim 1 wherein said substrate supporting means comprises a vertically movable and rotatably mounted circular substrate mounting means having a plurality of substrate accommodating openings disposed along the radially outer portion thereof;

a retaining plate means attached to the lower surface of said circular means and over said substrate accommodating openings to provide a support for a substrate and a monitor plate to rest on;

said retaining plate means having a plurality of openings therein registering with a substrate accommodating opening to permit vapors to pass therethrough onto said substrate and said monitor plate.

4. The combination of claim 1 wherein said pattern mask supporting means comprises a support means mounted in a plane parallel to the plane in which said substrate supporting means is mounted, said support means having a plurality of openings which are registerable with a number of the said plurality of substrates supported on said substrate supporting means;

a mask holding member yieldably mounted on said support means over each of said openings, said holding member having openings therein to permit the passage of vapors therethrough;

spring means disposed between said holding member and said support means, yieldably urging said holding member away from said support means and towards a retaining plate means attached to the lower surface of said substrate supporting means; and

an indexing member means integral with said mask holding member which registers with an indexing hole in said retaining plate means when said substrate supporting means is lowered and said retaining plate means contacts the mask that is placed on said mask holding member.

5. The combination of claim 1 wherein the sheathing means are so constructed as to permit vapor of a material from a said evaporating means in a selected source to be deposited on the surface of a preselected substrate supported in said substrate supporting means at a predetermined first angle of incidence, and thereafter upon a repositioning of said substrate by a rotation of said substrate supporting means, to permit vapor from another of said evaporating means in another selected source to be deposited on said surface at a second angle of incidence different from said first angle of incidence.

6. The combination of claim 5 wherein said sheathing means comprises a first sheathing means and a second sheathing means; and

wherein said first sheathing means is constructed so as to permit vapors of a material to be deposited from a first source on the surface of a substrate in a preselected position on said substrate supporting means in a selected one of three predetermined angles of incidence, wherein a first of said angles of incidence is at relative to the surface of said substrate, a second of said angles of incidence is less than 90 measured along the direction of rotation of said substrate supporting means and a third of said angles of incidence is greater than 90; and

wherein said second sheathing means is constructed so as to permit vapors of a material to be deposited from a second source on the surface of a substrate in a preselected position on said substrate supporting means at an angle of incidence of a magnitude intermediate said first and said second angles of incidence.

7. The combination of claim 1 and in addition a rotating means for rotating said substrate supporting means, comprising:

a disc means fixedly mounted on the shaft means on which said substrate supporting means is mounted, said disc means having a pluarlity of indexing holes near the outer edge thereof;

a stationary support means having a first indexing pin means registering with and passing through one of said indexing holes from the lower side of said disc means;

a lever arm means rotatably and slidably mounted about said shaft, and above said disc means;

said lever arm having a second indexing pin member extending from a lower surface thereof and registerable with said indexting holes;

a lever member having a free end, and another end pivotally connected to said lever arm and positioned to contact the lower end of said shaft, so that by raising the said free end, the said shaft is raised upwardly together with said disc means until said disc means clears said first indexing pin means from one of said indexing holes and simultaneously engages said second indexing pin member in another of said indexing holes, whereupon a sideWise movement of said free end of said lever member causes said disc means and said shaft to rotate, thereby rotating said substrate supporting means.

8. The combination of claim 7 and in addition a position indicating means operatively connected to said shaft supporting means is positioned.

References Cited by the Examiner UNITED STATES PATENTS Lyon 11849.1 X Koller 117106 X Blaustein 1187 X Theodoseau et al. 11849 X Fury et a1. 1188 0 CHARLES A. WILLMUTH, Primary Examiner.

RICHARD D. NEVIUS, Examiner.

Claims

1. IN A VACUUM CHAMBER HAVING MEANS TO EVACUATE GASES THEREFROM, THE COMBINATION COMPRISING: (A) A VERTICALLY MOVABLE SUBSTRATE SUPPORTING MEANS, ROTATABLY MOUNTED IN SAID CHAMBER, FOR SUPPORTING A PLURALITY OF SUBSTRATES IN A HORIZONTALLY DISPOSED PLANE; (B) A PLURALITY OF MATERIAL EVAPORATION SOURCE HOUSINGS MOUNTED IN SAID CHAMBER BELOW SAID SUBSTRATE SUPPORTING MEANS; (C) EVAPORATING MEANS IN SAID HOUSINGS; (D) A PATTERN MASK SUPPORTING MEANS, MOUNTED INTERMEDIATE SAID EVAPORATION SOURCE HOUSINGS AND SAID SUBSTRATE SUPPORTING MEANS, FOR SUPPORTING A PLURALITY OF MASKS IN A PLANE SUBSTANTIALLY PARALLEL TO THE PLANE IN WHICH SAID SUBSTRATES ARE SUPPORTED; (E) A PLURALITY OF SHUTTERS MOUNTED INTERMEDIATE SAID SOURCE HOUSINGS AND SAID MASK SUPPORTING MEANS AND OPERABLE TO BE POSITIONED SO AS TO PREVENT VAPORS FROM SELECTED SOURCES FROM BEING DEPOSITED ON PRE-