US3512369A - Ultrahigh-vacuum enclosure - Google Patents

Ultrahigh-vacuum enclosure Download PDF

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Publication number
US3512369A
US3512369A US783628A US3512369DA US3512369A US 3512369 A US3512369 A US 3512369A US 783628 A US783628 A US 783628A US 3512369D A US3512369D A US 3512369DA US 3512369 A US3512369 A US 3512369A
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US
United States
Prior art keywords
enclosure
casing
skirt
ultrahigh
reservoir
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US783628A
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English (en)
Inventor
Alain Houyvet
Pierre Noe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
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Publication of US3512369A publication Critical patent/US3512369A/en
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Expired - Lifetime legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/56—Apparatus specially adapted for continuous coating; Arrangements for maintaining the vacuum, e.g. vacuum locks
    • C23C14/564—Means for minimising impurities in the coating chamber such as dust, moisture, residual gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D8/00—Cold traps; Cold baffles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B37/00—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00
    • F04B37/06—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for evacuating by thermal means
    • F04B37/08—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for evacuating by thermal means by condensing or freezing, e.g. cryogenic pumps

Definitions

  • An ultrahigh-vacuum enclosure comprising a casing having a generally cylindrical shape formed of a lateral shell and two parallel end-walls, one end-wall being provided with a circular opening surmounted by a removable bell-housing which limits the volume of said enclosure.
  • a cylindrical skirt is mounted opposite to the circular opening and means are provided for displacing the skirt in sliding motion through the opening.
  • the skirt is provided in its outer surface with seals which are intended to be applied against raised bearing surfaces formed in the endwalls of the casing so as to define a closed annular chamber and a cryogenic pump is mounted within said annular chamber.
  • This invention relates to a sealed enclosure within which a high vacuum is produced for the main purpose of carrying out within said enclosure the deposition of metallic films on a substrate by vacuum evaporation, although other applications may be contemplated.
  • the present invention is directed to an ultrahigh-vacuum enclosure which makes it possible to achieve the object referred-to above by isolating the cryogenic pump or cold trap which is associated with said enclosure each time this latter is opened, the structure of the pump being additionally determined so that the conventional geometry of the enclosure is not modified.
  • the ultrahigh-vacuum enclosure in accordance with the invention which comprises a casing having a generally cylindrical shape formed of a lateral shell and ice two parallel end-walls, one end-wall being provided with a circular opening surmounted by a removable bell-housing which delimits the volume of said enclosure, is characterized in that it comprises a cylindrical skirt which is adapted to move along the axis of said casing through said opening, said skirt having a height which is substantially equal to that of said casing and provided in the outer surface thereof with seals which are intended to be applied against bearing surfaces formed in relief in the end-walls of said casing while defining a closed annular chamber, a cryogenic pump mounted within said annular chamber and means for producing the displacement of said skirt with respect to said casing.
  • said cryogenic pump comprises a first annular reservoir containing a liquefied gas and forming an outer thermal shield for a second annular reservoir which contains another liquefied gas.
  • said first reservoir surrounds said second reservoir on three sides, said second reservoir being provided in the outer surface which is directed towards the axis of said casing with flat circular plates forming condensation trays which are oriented at right angles to said axis.
  • said second reservoir is insulated from the central portion of said casing by means of a cooled inner shield comprising a plurality of metallic fins which prevent radiation in the direction of said annular chamber.
  • the means for controlling said cylindrical skirt are constituted by at least one pneumatic jack, the motion of said jack being imparted to a rod which traverses the endwalls of said casing and which is rigidly fixed to said skirt.
  • Small columns which are parallel to the axis of said casing are adapted to cooperate with runner-wheels carried by bearing-brackets which are rigidly fixed to said skirt so as to guide said skirt in its movement of displacement relative to said casing.
  • FIG. 1 is a diagrammatic axial sectional view of an enclosure in accordance with the invention
  • FIGS. 2 and 3 illustrate two alternative forms of construction of a detail of one of the portions of said enclosure.
  • the enclosure under consideration which is primarily intended for the deposition of metals by evaporation under vacuum, essentially comprises a casing 1 formed of a lateral cylindrical shell 2 and of two parallel end-walls 3 and 4 which are suitably joined to the ends of said shell with interposition of seals 5.
  • the upper end-wall 3 is provided at its center with a circular opening 6, a skirt 7 which is also of cylindrical shape being placed opposite to said opening.
  • Circular flanges 8 and 9 are provided respectively at each end of said skirt and adapted to accommodate seals which are designated respectively by the references 10 and 11.
  • the height of the skirt 7 is chosen so as to be substantially equal to that of the shell 2.
  • the skirt can be subjected to a movement of displacement along the axis of the casing 1 under the action of control means described hereinafter, said skirt is accordingly capable of closing said casing internally and of duplicating the shell 2, there being consequently formed between said shell and the end-walls 3 and 4 an annular chamber 12 which surrounds the axis of the casing.
  • the annular flanges 8 and 9 together with their respective seals 10 and 12 are capable of cooperating with two bearing surfaces 13 and '14 which are formed in relief in the end-walls 3 and 4 so as to ensure leaktightness of the annular chamber 12 with respect to the central portion of the casing.
  • cryogenic pump or cold trap which is advantageously constituted by a first reservoir 15 of annular shape which is filled with a liquefied gas and especially liquid nitrogen by means of a double duct 16 which traverses the endwall 3.
  • Said first reservoir 15 has a central portion 17 which duplicates the shell 2 towards the exterior of the casing and two lateral portions 18 and 19 which are parallel to the end-walls 3 and 4, thus surrounding on three sides a second reservoir 20 which is in turn filled with a second liquefied gas such as liquid helium.
  • the first reservoir 15 thus constitutes a thermal shield for the second reservoir 20 and insulates this latter from the outer wall of the casing 1, thereby preventing any loss of refrigeration towards the exterior.
  • a thin metallic shield 21 is advantageously placed between the casing and the first reservoir so as to provide this latter with thermal protection against direct radiation from the casing wall, the outer face of which is at ambient temperature.
  • the second reservoir 20 is provided in the outer surface which is directed towards the axis of the casing 1 with flat circular plates 22 forming condensation trays; furthermore, this reservoir can be thermally insulated from the internal region of the casing 1 by means of a second shield 49 which is fixed between the lateral portions 18 and 19 of the reservoir 15 and formed by an assembly of flat metallic fins of which two particular profiles are illustrated in FIGS. 2 and 3.
  • said flat fins 23 are endowed with relatively high thermal conductivity whereas in the case of FIG. 2, the fins 24 have a herringbone configuration, which endows them with a greater degree of opacity but reduces the pumping speed in proportion.
  • the equipment of the ultrahigh-vacuum enclosure under consideration is completed by means of small spacing columns 25 which are disposed between the end-walls 3 and 4 of the casing I. Said columns serve in particular to transmit forces which arise from atmospheric pressure to the two end-walls while preventing any deformation or compression within the annular chamber 12 when the interior of the chamber is evacuated.
  • said chamber is limited externally by a bell-housing 26 having a flange 27 fitted with a seal 28 which is intended to be fitted within a groove 29 formed in the end-wall 3, said bell-housing which is shown partially in FIG. 1 being adapted to cover the entire opening 6 of the skirt 7.
  • the second end-wall 4 is rigidly fixed by means of screws 30 to a support plate 31 in which is formed a passage 32 for a rod 33, one end of which is fitted with a device 34 for fastening the rod to the skirt 7.
  • said rod is provided with an enlarged portion forming a piston 50 which is mounted within a sleeve 35, said sleeve being secured to the underface of the support plate 31 with interposition of a seal 36.
  • an O-ring seal 51 is fitted in the top face of said piston 50 in order to isolate the internal portion of the sleeve 35 from the enclosure when the skirt 7 is located in the top position thereof.
  • the piston 50 can be duplicated by a second piston 37, both pistons being fitted with sealing rings 38 in order to isolate the interior of the enclosure from the outer atmosphere which is in contact with the extremity of the sleeve 35.
  • the rod 33 is keyed to a plate 39 which is fastened by means of screws 40 to the rods 41 and 42 of two pneumatic jacks 43 and 44 which are fixed beneath the support plate 31. Said two jacks are operated in synchronism and permit the displacement of the skirt 7 along the axis of the casing 1.
  • the skirt is guided during its movement by means of small columns 45 which are mounted between the support plate 31 and a top plate 46 through the end-walls 3 and 4, said columns being intended to cooperate with runner-wheels 47 carried by bearing-brackets 48 which are fixed against the inner surface of the skirt 7.
  • a vacuum is first created within the enclosure by means of a conventional pump set such as a backing pump coupled with a highvacuum diffusion pump, whereupon the skirt is lifted and the pressure is reduced and maintained in the ultrahigh region by the cryogenic pump or cold trap which is constituted by the reservoirs 15 and 20 and more especially by the condensation trays 22 of the second reservoir 20, the fins 23 and 24 and the shield 21 being intended to prevent direct radiation from any heat sources towards the cold surface of the trap which is thus provided.
  • the skirt 7 is in the top position thereof; the bell-housing 26 is tightly applied against the end-wall 3.
  • the annular chamber 12 which contains the cold trap is first sealed in order to maintain the low temperature which has been produced and to prevent unnecessary heating of said trap by the surrounding atmosphere.
  • the jacks 43 and 44 are actuated in the direction which results in the downward movement of the rod 33 and consequently of the skirt 7 until this latter comes into abutment in the bottom position thereof with its seals 10' and 11 applied against the bearing surfaces 13 and 14 of the end-walls 3 and 4,
  • the invention is not limited to the example of construction which has been more especially contemplated but extends on the contrary to all alternative forms.
  • the ultrahigh-vacuum enclosure considered finds an advantageous application in the deposition of metals by vacuum evaporation, it will be apparent that other applications could also be contemplated each time it proves necessary to employ an enclosure which makes it possible to carry out operations under a vacuum within a short period of time while nevertheless retaining the possibility of opening the enclosure or even of increasing the pressure at frequent intervals.
  • An ultrahigh-vacuum enclosure comprising a casing having a generally cylindrical shape formed of a later- 211 shell and two parallel end-Walls, one end-wall being provided with a circular opening surmounted by a removable bell-housing 'which delimits the volume of said enclosure, characterized in that it comprises a cylindrical skirt which is adapted to move along the axis of said casing through said opening, said skirt having a height which is substantially equal to that of said casing and provided in the outer surface thereof with seals which are intended to be applied against bearing surfaces formed in relief in the end-walls of said casing while defining a closed annular chamber, a cryogenic pump mounted within said annular chamber and means for producing the displacement of said skirt with respect to said casing.
  • cryogenic pump comprises a first annular reservoir containing a liquefied gas and forming an outer thermal shield for a second annular reservoir which contains another liquefied gas.
  • An ultrahigh-vacuum enclosure in accordance with claim 1 characterized in that small columns which are parallel to the axis of said casing are adapted to cooperate with runner-wheels carried by bearing-brackets Which are rigidly fixed to said skirt so as to guide said skirt in its movement of displacement relative to said casing.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Physical Deposition Of Substances That Are Components Of Semiconductor Devices (AREA)
  • Physical Vapour Deposition (AREA)
US783628A 1968-01-05 1968-12-13 Ultrahigh-vacuum enclosure Expired - Lifetime US3512369A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR135093 1968-01-05

Publications (1)

Publication Number Publication Date
US3512369A true US3512369A (en) 1970-05-19

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US783628A Expired - Lifetime US3512369A (en) 1968-01-05 1968-12-13 Ultrahigh-vacuum enclosure

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US (1) US3512369A (is")
BE (1) BE725393A (is")
DE (1) DE1900454A1 (is")
ES (1) ES362123A1 (is")
FR (1) FR1557891A (is")
GB (1) GB1181750A (is")
LU (1) LU57621A1 (is")
NL (1) NL6900130A (is")

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4311018A (en) * 1979-12-17 1982-01-19 Varian Associates, Inc. Cryogenic pump
US4438632A (en) * 1982-07-06 1984-03-27 Helix Technology Corporation Means for periodic desorption of a cryopump
US4763483A (en) * 1986-07-17 1988-08-16 Helix Technology Corporation Cryopump and method of starting the cryopump

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2319035A1 (fr) * 1975-07-22 1977-02-18 Physimeca Appareil pour faire le vide a l'interieur d'une enceinte
US4907413A (en) * 1988-06-02 1990-03-13 Grumman Aerospace Corporation Regenerable cryosorption pump with movable physical barrier and physical barrier thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2737779A (en) * 1946-05-24 1956-03-13 Ernest O Lawrence Condensable vapor extraction apparatus
US3327491A (en) * 1966-06-08 1967-06-27 Andonian Associates Inc Windowless vacuum chamber for exposing a cooled device to successive samplers
US3360949A (en) * 1965-09-20 1968-01-02 Air Reduction Cryopumping configuration

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2737779A (en) * 1946-05-24 1956-03-13 Ernest O Lawrence Condensable vapor extraction apparatus
US3360949A (en) * 1965-09-20 1968-01-02 Air Reduction Cryopumping configuration
US3327491A (en) * 1966-06-08 1967-06-27 Andonian Associates Inc Windowless vacuum chamber for exposing a cooled device to successive samplers

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4311018A (en) * 1979-12-17 1982-01-19 Varian Associates, Inc. Cryogenic pump
US4438632A (en) * 1982-07-06 1984-03-27 Helix Technology Corporation Means for periodic desorption of a cryopump
US4763483A (en) * 1986-07-17 1988-08-16 Helix Technology Corporation Cryopump and method of starting the cryopump

Also Published As

Publication number Publication date
GB1181750A (en) 1970-02-18
NL6900130A (is") 1969-07-08
BE725393A (is") 1969-05-16
FR1557891A (is") 1969-02-21
DE1900454A1 (de) 1969-09-04
LU57621A1 (is") 1969-04-08
ES362123A1 (es) 1970-11-01

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