U.S. patent number 3,584,847 [Application Number 04/733,553] was granted by the patent office on 1971-06-15 for advancing workpieces through a sputtering chamber.
This patent grant is currently assigned to Western Electric Company, Inc.. Invention is credited to Charles S. Hammond, Jr., Paul M. Johnson, Jr., Joseph C. Tribble, Robert M. Tribble.
United States Patent |
3,584,847 |
Hammond, Jr. , et
al. |
June 15, 1971 |
ADVANCING WORKPIECES THROUGH A SPUTTERING CHAMBER
Abstract
An apparatus for depositing a thin film of tantalum to
workpieces includes a sputtering chamber and entrance and exit
chambers located at opposite ends of and communicating with the
sputtering chamber. Sealing devices are provided for isolating the
sputtering chamber from the entrance and exit chambers. A
reciprocating conveyor having a central conveyor section located
within the sputtering chamber, and first and second conveyor
sections, located in the entrance and exit chambers, respectively,
and which sections may all be connected together, is provided for
advancing workpieces from a first magazine in the entrance chamber,
through the sputtering chamber, to a second magazine in the exit
chamber.
Inventors: |
Hammond, Jr.; Charles S.
(Winston-Salem, NC), Tribble; Joseph C. (Winston-Salem,
NC), Tribble; Robert M. (Winston-Salem, NC), Johnson,
Jr.; Paul M. (Winston-Salem, NC) |
Assignee: |
Western Electric Company, Inc.
(New York, NY)
|
Family
ID: |
24948103 |
Appl.
No.: |
04/733,553 |
Filed: |
May 31, 1968 |
Current U.S.
Class: |
432/86; 118/729;
204/298.25; 118/719; 118/733; 432/126; 414/937; 414/939 |
Current CPC
Class: |
C23C
14/56 (20130101); Y10S 414/137 (20130101); Y10S
414/139 (20130101) |
Current International
Class: |
C23C
14/56 (20060101); F27b 009/02 (); F27b
009/24 () |
Field of
Search: |
;263/6,36 ;215/17.4 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Camby; John J.
Claims
What we claim is:
1. An apparatus for moving articles through a treating chamber
having a controlled atmosphere maintained therein, which
comprises:
a reciprocating conveyor for advancing articles through the
treating chamber, said conveyor including (1) a central conveyor
section mounted for reciprocating movement in the treating chamber
and (2) first and second conveyor sections, mounted for
reciprocating movement at opposite ends of the treating chamber,
detachably connected to said central conveyor section; and
means for sealing the treating chamber from the outside atmosphere
when said conveyor sections are disconnected.
2. An apparatus for moving articles through a treating chamber
having entrance and exit openings formed in opposite sides thereof
and having a controlled atmosphere maintained therein, which
comprises:
a reciprocating conveyor for advancing articles through the
treating chamber, said conveyor including (1) a central conveyor
section extending through the treating chamber and mounted for
reciprocating movement along a path extending between the entrance
and exit openings formed in the chamber, (2) first and second
conveyor sections located outside the treating chamber at opposite
ends of and aligned with said central conveyor section and mounted
for reciprocating movement along paths parallel to the path of
reciprocation of said central conveyor section;
means selectively operable for coupling said first and second
conveyor sections together;
means for imparting reciprocating movement to the coupled conveyor
sections to advance articles through the treating chamber during
forward movement of the conveyor sections; and
means for sealing the entrance and exit openings of the treating
chamber to seal the interior of the chamber from the ambient
atmosphere when said conveyor sections are uncoupled.
3. An apparatus for moving articles through a treating chamber
having entrance and exit openings formed in opposite sides thereof
and having a controlled atmosphere maintained therein, as set forth
in claim 2, which includes:
means on said conveyor sections for engaging articles to be
advanced during the forward movement of the conveyor sections and
for disengaging the articles during backward movement of said
conveyor sections.
4. An apparatus for moving articles through a treating chamber
having entrance and exit openings formed in opposite sides thereof
and having a controlled atmosphere maintained therein, as set forth
in claim 3, wherein:
said article-engaging means comprises a plurality of
gravity-operated fingers, pivotally mounted to the conveyor
sections at equal distances along said conveyor sections, said
fingers being normally urged into article-engaging positions by
gravity during forward movement of the conveyor sections and being
pivoted to bypass the articles during backward movement of said
conveyor sections.
5. In an apparatus for moving articles through a treating chamber
having entrance and exit openings formed in opposite sides thereof
and having a controlled atmosphere maintained therein:
entrance and exit chambers located at opposite ends of and
communicating with the treating chamber through the entrance and
exit openings, respectively;
a conveyor for advancing articles from said entrance chamber,
through said treating chamber to said exit chamber, said conveyor
including (1) a central conveyor section mounted in said treating
chamber for reciprocating movement in a path extending from the
entrance opening to the exit opening, and (2) first and second
conveyor sections, mounted in said entrance and exit chambers,
respectively, for reciprocating movement in paths parallel to the
path of reciprocation of said central conveyor section;
means selectively operable for connecting said first and second
conveyor sections to said central conveyor section;
means for imparting reciprocating movement to the connected
conveyor sections to advance articles through said treating chamber
during forward movement of said conveyor sections; and
means operable when said conveyor sections are disconnected for
sealing said entrance and exit chambers from said treating
chamber.
6. In an apparatus for conveying articles through a treating
chamber having a controlled atmosphere maintained therein:
entrance and exit chambers located at opposite ends of and
communicating with the treating chamber;
a conveyor track having a center track section extending through
the treating chamber for receiving and guiding articles in movement
through that chamber, a first track section extending from said
entrance chamber toward said center track section and a second
track section extending from said exit chamber toward said center
track section;
first means located between said entrance chamber and the treating
chamber and mounted to move between said first and center track
sections for sealing the treating chamber from said entrance
chamber;
second means located between said exit chamber and the treating
chamber mounted to move between said center and second track
sections for sealing the treating chamber from said exit chamber;
and
article-engaging means mounted for reciprocating movement along
said track sections to move articles from said entrance chamber
through the treating chamber to said exit chamber, said engaging
means including a central portion for engaging articles on said
center track section and first and second portions separable from
said central portion for engaging articles on said first and second
track sections, respectively.
7. An apparatus for advancing workpieces through a sputtering
chamber having entrance and exit openings formed in opposite sides
thereof and having a controlled atmosphere maintained therein,
which comprises:
entrance and exit chambers located at opposite ends of and
communicating with the sputtering chamber through the entrance and
exit openings, respectively;
central guide means extending through the sputtering chamber for
receiving and guiding workpieces in movement through that
chamber;
first and second guide means located in said entrance and exit
chambers, respectively, and aligned with said central guide means
in the sputtering chamber;
workpiece-advancing means mounted for reciprocating movement along
said guide means to engage and move workpieces along said guide
means to engage and move workpieces along said first guide means in
said entrance chamber to said central guide means in the sputtering
chamber and then to said second guide means in said exit chamber,
said advancing means including a central portion for engaging
workpieces on said central guide means and first and second
portions, which may be coupled to said central portion for engaging
workpieces on said first and second guide means, respectively;
means for imparting reciprocating movement to said
workpiece-advancing means after the portions thereof are coupled
together to advance workpieces along said guide means during
forward movement of said workpiece-advancing means in a direction
extending from said entrance chamber toward said exit chamber;
a first sealing device located between said entrance chamber and
the sputtering chamber for sealing the sputtering chamber from said
entrance chamber when said first and central portions of said
workpiece-engaging means are uncoupled; and
a second sealing device located between said exit chamber and the
sputtering chamber for sealing the sputtering chamber from said
exit chamber when the central and second portions of said
workpiece-engaging means are uncoupled.
8. An apparatus for advancing workpieces through a sputtering
chamber having entrance and exit openings formed in opposite sides
thereof and having a controlled atmosphere maintained therein, as
set forth in claim 7, which includes:
a plurality of fingers, pivotally mounted on the portions of said
workpiece-advancing means at equal distances therealong, for
engaging workpieces on said guide means during forward movement of
said workpiece-advancing means and for disengaging the workpieces
during backward movement of said workpiece-advancing means.
9. An apparatus for advancing workpieces through a sputtering
chamber having entrance and exit openings formed in opposite sides
thereof and having a controlled atmosphere maintained therein, as
set forth in claim 8, wherein:
said fingers are normally urged into workpiece-engaging positions
by gravity during forward movement of said workpiece-advancing
means and are pivoted to bypass the advanced workpieces during
backward movement of said workpiece-advancing means.
10. An apparatus for advancing workpieces through a sputtering
chamber having entrance and exit openings formed in opposite sides
thereof and having a controlled atmosphere maintained therein, as
set forth in claim 7, which includes:
heating means mounted in said entrance chamber for raising the
temperature of workpieces located in said entrance chamber to a
desired level prior to advancement of the workpieces into the
sputtering chamber.
11. An apparatus for advancing workpieces through a sputtering
chamber having entrance and exit openings formed in opposite sides
thereof and having a controlled atmosphere maintained therein, as
set forth in claim 7, which includes:
a first magazine located within said entrance chamber for receiving
a plurality of workpieces to be advanced through the sputtering
chamber, said first magazine being mounted to move relative to the
first portion of said workpiece-advancing mechanism to feed the
workpieces, one at a time, to said first portion of said
workpiece-advancing mechanism;
a second magazine located with said exit chamber for receiving
workpieces after advancement thereof through the sputtering
chamber, said second magazine being mounted to move relative to the
second portion of said workpiece advancing mechanism to remove
workpieces, one at a time, from said second portion of said
workpiece-advancing mechanism; and
means for moving said first and second magazines relative to said
first and second portions of said workpiece-advancing mechanism,
respectively, to feed workpieces to said workpiece-advancing
mechanism in said entrance chamber and to remove workpieces from
said advancing mechanism in said exit chamber.
12. An apparatus for moving articles into a treating chamber having
an entrance opening formed therein and having a controlled
atmosphere maintained therein, which comprises:
a conveyor for advancing articles through the entrance opening into
the treating chamber, said conveyor including (1) an internal
conveyor section located inside the treating chamber with one end
thereof adjacent to the entrance opening, said internal section
being mounted for reciprocating movement and (2) an external
conveyor section located outside the treating chamber with one end
thereof adjacent to the entrance opening, said external conveyor
section also mounted for reciprocating movement;
means selectively operable for connecting said external conveyor
section to said internal conveyor section;
means for imparting reciprocating movement to the connected
conveyor sections to advance articles from said external conveyor
section to said internal conveyor section; and
means for sealing the treating chamber from the ambient atmosphere
when said internal and external conveyor sections are
disconnected.
13. In an apparatus for moving articles into a treating chamber
having an entrance opening formed therein and having a controlled
atmosphere maintained therein:
an entrance chamber located at one end of and communicating with
the treating chamber through the entrance opening;
a conveyor for advancing articles from said entrance chamber
through the entrance opening into said treating chamber, said
conveyor including (1) an internal conveyor section located inside
the treating chamber with one end thereof adjacent to the entrance
opening, said internal conveyor section mounted for reciprocating
movement along a path extending from the entrance opening into the
treating chamber, and (2) an external conveyor section located in
the entrance chamber with one end thereof adjacent to the entrance
opening, said external conveyor section being mounted for
reciprocating movement along a path parallel to the path of
reciprocation of said internal conveyor section;
means selectively operable for coupling said external conveyor
section to said internal conveyor section;
means for imparting reciprocating movement to the coupled conveyor
sections to advance articles from said entrance chamber into the
treating chamber; and
means for sealing said treating chamber from said entrance chamber
when said internal and external conveyor sections are
disconnected.
14. An apparatus for conveying articles, which comprises:
a central conveyor section mounted for reciprocating movement along
a path through which articles are to be conveyed;
first and second conveyor sections located adjacent to opposite
ends of the central conveyor section and mounted for reciprocating
movement along said path;
means selectively operable for connecting said first and second
conveyor sections to said central conveyor section; and
means for imparting reciprocating movement to the connected
conveyor sections to advance articles, during forward movement of
the conveyor sections, from said first conveyor section along said
central conveyor section to said second conveyor section.
15. An apparatus for conveying articles, as set forth in claim 14,
which includes:
means on said conveyor sections for engaging articles to be
advanced during forward movement of said conveyor sections and for
disengaging the advanced articles during backward movement of said
conveyor sections.
16. An apparatus for conveying articles, as set forth in claim 15,
wherein:
said article-engaging means comprises a plurality of
gravity-operated fingers located at equal distances along said
conveyor sections which are urged into article engaging positions
by gravity during forward movement of the conveyor sections and
pivot to bypass the advanced articles during backward movement of
said conveyor sections.
17. In an apparatus for conveying articles:
a first conveyor section mounted for reciprocating movement along a
path in which articles are to be conveyed;
a second conveyor section mounted for reciprocating movement along
said path and located adjacent to said first conveyor section;
connecting means operated upon movement of said first conveyor
section into engagement with said second conveyor section for
connecting said first and second conveyor sections; and
means for imparting reciprocating movement to said first conveyor
section to (1) move said first conveyor section into engagement
with the second conveyor section to connect said sections together
and (2) to advance articles from said first conveyor section along
said second conveyor section.
18. In apparatus for conveying articles, as set forth in claim
17:
means for disabling said connecting means to allow said first and
second conveyor sections to be separated.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
In the manufacture of electrical devices, such as tantalum thin
film resistors, it is desirable to apply a thin film of tantalum to
a workpiece by cathode-sputtering techniques. In order that the
sputtering operation be commercially practicable, workpieces to
which the thin film of tantalum is applied should be processed
continuously through an apparatus capable of performing the
sputtering operation. Thus, a sputtering apparatus which is
designed to continuously advance workpieces through a sputtering
chamber is commercially desirable.
In addition to being designed for continuous processing, the
sputtering apparatus should also prevent the ambient atmosphere
from affecting the atmosphere inside the sputtering chamber. Thus,
a sputtering machine which may be completely isolated from the
ambient atmosphere is also commercially desirable. The sputtering
machine should be capable of adequately preheating the workpieces
before advancement thereof into the sputtering chamber. It is also
desirable that the speed of advancement of the workpieces through
the apparatus be controllable.
2. Description of the Prior Art
In the prior art, various sputtering arrangements have been used to
apply a thin film of tantalum to a workpiece. The earliest
apparatus used for sputtering included a bell jar into which
workpieces to be coated with a tantalum film were inserted. The
bell jar apparatus had two primary disadvantages: First, it was not
designed for continuous processing of workpieces; and second, the
bell jar had to be completely evacuated each time a new batch of
workpieces were placed inside.
After development of the bell jar sputtering apparatus, sputtering
machines were designed which were capable of continuously
processing workpieces through a sputtering chamber. Some machines
utilized a sputtering chamber which was, at all times, completely
isolated from the ambient atmosphere. Such sputtering machines
utilized airlocks located at opposite ends of the machine for
feeding workpieces, one at a time, into the sputtering apparatus
and for removing workpieces from the sputtering chamber in the same
fashion. Other sputtering machines employed a sputtering chamber
which was continuously in communication with the ambient atmosphere
through restricted openings in opposite ends of the sputtering
chamber. In such a machine workpieces could be continuously
advanced through the sputtering chamber on a conveyor which
extended between the openings in the opposite ends of the chamber.
The restricted openings were designed such that the ambient
atmosphere had a minimal affect upon the atmosphere maintained in
the sputtering chamber.
Another type of sputtering machine, which utilized a sputtering
chamber completely isolated from the ambient atmosphere, employed a
conveying arrangement in which magazines were fed into the
sputtering chamber through airlocks located at entrance and exit
sides of the chamber. Once the magazines were located within the
sputtering chamber, workpieces were advanced, one at a time, from
the magazine at the entrance side of the chamber to the magazine at
the exit side of the chamber.
Thus, prior art machines capable of continuously processing
workpieces through a sputtering chamber completely isolated from
the ambient atmosphere require specially designed airlocks located
at opposite ends of the chamber and feeding mechanisms associated
with the airlocks for advancing workpieces to and from the exit and
entrance locks, respectively. In view of the prior art, a
sputtering machine, capable of continuously processing workpieces
through a sputtering chamber completely isolated from the ambient
atmosphere, utilizing a single conveyor for advancing articles
therethrough is desirable. Such an apparatus would eliminate the
necessity of providing special handling mechanisms associated with
the entrance and exit airlocks to assist a conveyor located within
the sputtering chamber to advance workpieces through the
apparatus.
SUMMARY OF THE INVENTION
The present invention contemplates an apparatus for moving articles
through a treating chamber having a controlled atmosphere, such as
a sputtering chamber. The apparatus includes a central conveyor
section and first and second conveyor sections extending to and
from respective entrance and exit openings of the treating chamber.
When the conveyor sections are connected together, they may be
reciprocated to advance articles into and out of the treating
chamber. When the conveyor sections are disconnected, sealing
facilities at the respective entrance and exit openings may be
operated to seal the treating chamber from the ambient
atmosphere.
Additionally, the apparatus includes entrance and exit chambers at
the respective entrance and exit openings of the treating chamber.
The entrance and exit chambers may themselves be isolated from the
ambient atmosphere and provided with respective controlled
atmospheres. The first and second conveyor sections are located
within the respective entrance and exit chambers. Articles may be
subjected to preconditioning and post conditioning in the
respective entrance and exit chambers, such as heating and
outgassing in the entrance chamber and cooling in the exit chamber,
for any desired lengths of time before and after treatment in the
treating chamber.
Further, the apparatus is provided with first and second magazines
which are mounted within the entrance and exit chambers,
respectively. In the operation of the apparatus, the first magazine
is loaded with workpieces to be advanced through the sputtering
chamber. The second magazine is provided for receiving workpieces
which have been advanced through the sputtering chamber. The first
conveyor section is designed to remove workpieces from the first
magazine and to advance the workpieces to the central section of
the conveyor. The second conveyor section receives workpieces
advanced along the central conveyor section and inserts the
workpieces into the second magazine. When the first magazine is
completely exhausted and the second magazine is completely filled,
the conveyor sections are disconnected and the sputtering chamber
is sealed. Then the entrance and exit chambers are opened to permit
the processed workpieces to be removed from the second magazine and
unprocessed workpieces to be loaded into the first magazine.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an elevation view, partially in section, of a sputtering
apparatus which operates in accordance with the principles of the
present invention.
FIG. 2 illustrates schematically first and second magazines located
in entrance and exit chambers, respectively, of the sputtering
apparatus, and a conveyor along which workpieces are advanced from
the first magazine through a sputtering chamber to the second
magazine.
FIG. 3 is an enlarged view of a portion of the conveyor shown in
FIG. 2.
FIG. 4 is an elevation view, partially in section, of the entrance
chamber and a first section of the conveyor located therein.
FIG. 5 is a sectional view of the first section of the conveyor
taken along line 5-5 of FIG. 4.
FIG. 6 is an elevation view, partially in section, of the exit
chamber and a second section of the conveyor located therein.
DETAILED DESCRIPTION
In FIG. 1, a sputtering apparatus which incorporates the principles
of the present invention is shown. The apparatus includes an
entrance chamber 19, a sputtering chamber 21, and an exit chamber
23. The sputtering chamber 21 contains a sputtering cathode 25 for
applying a metallic coating, such as tantalum, to workpieces
advanced through the chamber 21. A first magazine Ml, located in
the entrance chamber 19, is provided for receiving unprocessed
workpieces to be advanced through the sputtering apparatus.
Surrounding the magazine Ml is a plurality of heating elements
20-20. The heating elements 20-20 are utilized to raise the
temperature of workpieces in the magazine Ml prior to advancement
of the workpieces through the apparatus. A second magazine M2 is
mounted in the exit chamber 23 for receiving processed
workpieces.
An auxiliary heating chamber 24 is located between the entrance
chamber 19 and the sputtering chamber 21 and communicates with the
entrance chamber 19 through a first sealing device 26. The chamber
24 contains a heating element 22 which is used to maintain
workpiece temperature at the level to which the temperature is
raised in the entrance chamber 19. Similarly, a chamber 28 is
located between the sputtering chamber 21 and the exit chamber 23
and communicates with the exit chamber through a second sealing
device 29. The chamber 28 provides for initial cooling of the
workpieces after advancement through the sputtering chamber 21. The
primary cooling operation is, however, conducted in the exit
chamber 23. The chambers 24 and 28 also serve as buffers for the
sputtering chamber 21 to protect the atmosphere in chamber 21 from
being contaminated by the atmosphere in the entrance and exit
chambers 19 and 23, respectively.
As shown in FIG. 4, the first sealing device 26 is provided with a
slide 26' which may be moved between the entrance chamber 19 and
the chamber 24 to seal the chambers 19 and 24 from each other. In
similar fashion, the second sealing device 29 (FIG. 6) is provided
with slide 29' which may be moved between the chamber 28 and exit
chamber 23 to seal the chambers 23 and 28 from each other.
CONVEYOR
Referring to FIGS. 1 and 2, a conveyor 30 is utilized to advance
articles from the entrance chamber 19 through the sputtering
chamber 21 to the exit chamber 23. The conveyor 30 comprises three
separate portions: (1) a central conveyor section 31 which extends
through the sputtering chamber 21 and through the buffer chambers
24 and 28, respectively; (2) a first conveyor section 32 located
within the entrance chamber 19 and extending toward the chamber 24;
and (3) a second conveyor section 33 located in the exit chamber 23
and extending toward the chamber 28.
In general, the conveyor 30 includes a pair of stationary parallel
guide rails along which workpieces are advanced by a reciprocating
advancing mechanism located between the guide rails. As shown in
FIGS. 2 and 3, the first section 32 of the conveyor 30 includes a
pair of stationary parallel guide rails 42-42. The guide rails
42-42 have longitudinal grooves 42'-42' (FIG. 5) formed on the
inner sides thereof for receiving and supporting a workpiece for
sliding movement along the guide rails 42-42. Between the guide
rails 42-42, a workpiece-advancing mechanism is located. The
workpiece-advancing mechanism includes a bar 43 (FIG. 3) mounted
for reciprocating movement along a path parallel to the guide rails
42-42. The bar 43 comprises a pair of parallel strips 39-39 which
are fastened together by a set of spacers 41-41 located at equal
distances along the strips 39-39.
The guide rails 42-42 (FIG. 4) are supported by wall 19' of the
entrance chamber 19 and by a yoke 34 mounted within a tubular
section 35 of the apparatus located between the chamber 19 and the
sealing device 26. As shown in FIG. 5, the yoke 34 includes a pair
of plates 36 and 36' which are fitted together about the guide
rails 42-42. Projecting from the sides of the plates 36 and 36' are
a set of adjustable arms 37-37 which are used to support the yoke
34 within the tubular section 35. The plate 36' is provided with an
opening for receiving the bar 43. At the bottom of the opening, a
bead 38 of wear-resistant material, such as hard steel, is provided
to support the bar 43 for reciprocating movement. A similar bead
38' (FIG. 4) is mounted on the wall 19' of chamber 19 to support
the bar 43. The yoke 34 also supports a pair of roller bearings
40-40 for engaging the sides of bar 43 and guiding the bar 43 in
its reciprocating movement. In addition, a pair of guide plates
40'-40' (FIG. 5) are mounted on the yoke 34 above the bar 43 to
confine the bar 43 in a desired location in the opening formed in
plate 36'.
Referring to FIG. 3, the bar 43 supports a plurality of
workpiece-engaging fingers 44-44 which are pivotally mounted within
slots 45-45 located between the spacers 41-41. The fingers 44-44
are mounted on pivot pins 44'-44' such that each finger 44, under
the effect of gravity, is normally pivoted into a position where
one end of the finger 44 rests upon a stop 46 and the other end
projects above the bar 43 to engage workpieces to be advanced. When
the bar 43 is moved to the left, as viewed in FIG. 3, the fingers
44-44 engage the edges of the workpieces located in the path of
movement defined by the guide rails 42-42 to advance the workpieces
along the guide rails 42-42.
In order to impart reciprocating movement to the bar 43, a rack 47
and pinion 48 (FIG. 4) are provided. The rack 47 is secured to the
bar 43. The pinion 48 engages the rack 47 and is driven by a motor
49 (FIG. 4) to impart movement to the bar 43.
The second section 33 (FIGS. 2 and 6) of conveyor 30 also includes
a pair of parallel stationary guide rails 52-52 having longitudinal
grooves 52'-52' formed on the inner sides thereof to receive
workpieces advanced along the conveyor 30. The guide rails 52-52
are supported by wall 23' of the exit chamber 23 and by a yoke 57
(FIG. 6) which is similar to yoke 34 shown in FIG. 5. A bar 53,
which supports a plurality of workpiece engaging fingers 54-54, is
mounted for reciprocating movement in a path parallel to the guide
rails 52-52. The bar 53 is supported for reciprocating movement by
a wear-resistant bead 58' mounted on wall 23' of chamber 23 and by
a similar bead (not shown) mounted on the yoke 57. The fingers
54-54 are pivotally mounted to the bar 53 within slots 55-55 formed
in the bar 54 at equal distances therealong. The fingers 54-54 are
arranged to be normally pivoted upward into positions to engage
workpieces supported by the guide rails 52-52.
The central section 31 (FIG. 2) of the conveyor 30 includes a pair
of parallel guide rails 62-62 having longitudinal grooves 62'-62'
(FIGS. 4 and 6) formed on the inner sides thereof for receiving and
supporting workpieces. As indicated in FIG. 2, the guide rails
62-62 are divided into a series of rail sections to allow for
longitudinal expansion thereof resulting from the heat generated
during the operation of the apparatus. Referring to FIG. 1, the
guide rail sections are supported by the chamber walls through
which the rail sections are inserted and by flexible supports
located in the center of each of the chambers 21, 24, and 28. A
pair of yokes 67 and 68 (FIGS. 4 and 6, respectively) are also
provided for supporting the guide rails 62-62.
A bar 63 is mounted between the guide rails 62-62 for reciprocating
movement in the path parallel to the guide rails 62-62. The bar 63
is supported for reciprocating movement by wear-resistant beads
formed on the yokes 67 and 68 and by similar beads located in the
walls of chambers 21, 24, and 28. The bar 63 also supports a
plurality of workpiece-engaging fingers 64-64 which are pivotally
mounted within slots 65-65 formed at equal distances along the bar
63. The fingers 64-64 are mounted on the bar 63 in such fashion
that, under the action of gravity, the fingers 64-64 are normally
pivoted upward into workpiece engaging positions.
Referring to FIG. 4, the guide rails 42-42 are aligned with and
spaced from the center guide rails 62-62 to permit the slide 26' of
the sealing device 26 to move therebetween to seal the entrance
chamber 19 from the heating chamber 24. Similarly, as shown in FIG.
6, the guide rails 52-52 are aligned with and spaced from the
center guide rails 62-62 to permit the slide 29' of the sealing
device 29 to move therebetween and seal the exit chamber 23 from
the cooling chamber 28.
As shown in FIGS. 1 and 2, the chamber 24 is provided with a pair
of devices 50-50 for establishing restricted openings through which
workpieces are advanced during movement along conveyor 30. The
devices 50-50 are mounted over the guide rails of conveyor 30 and
located at opposite sides of the chamber 24. The purpose of the
devices 50-50 is to isolate, as effectively as possible, the
chambers 19 and 24 from the sputtering chamber 21. Similarly, the
chamber 28 is also provided with a pair of devices 50'-50' for
isolating the sputtering chamber 21 from the chambers 23 and
28.
WORKPIECE-ADVANCING MECHANISM
The reciprocating mechanism for advancing workpieces along the
guide rails 42-42, 52-52, and 62-62 of the conveyor 30, consists of
three separate portions; i.e., the reciprocating bars 43, 53, and
63 and the associated workpiece-engaging fingers 44-44, 54-54, and
64-64, described above. Referring to FIG. 4, the bar 63 is provided
at the end thereof adjacent to the sealing device 26 with a latch
71 pivotally mounted thereon. The latch 71 has a notch 71' formed
therein for engaging a projection 72 extending from the bar 43. A
stationary air cylinder 73, located outside the sealing device 26,
is provided for operating the latch 71. A piston rod 74 extending
from the air cylinder 73 through a tubular section 75 of the
sputtering apparatus supports a member 76 having a projection 76'
for engaging an arm 77 extending from the latch 71. When the air
cylinder 73 is operated to move the piston rod 74 downward, the
projection 76' moves into engagement with the arm 77 to pivot the
latch 71.
In the operation of the apparatus, when the pinion 48 is rotated to
move the bar 43 leftward, as viewed in FIG. 4, the projection 72 on
the bar 43 moves to a position where it is engaged by the latch 71
to couple the bars 43 and 63 together. Thereafter, reciprocating
movement may be imparted to the coupled bars 43 and 63 through the
rack 47 and pinion 48. The bars 43 and 63 may be uncoupled by
returning the bar 63 to its initial position (FIG. 4) and operating
the air cylinder 73 to pivot the latch 71 which disengages the
projection 72. The bar 43 may be returned to its initial position
without moving the bar 63.
A similar coupling arrangement (FIG. 6) is provided for connecting
the bar 53 to the other end of the bar 63. A latch 81, pivotally
mounted on the bar 53, has a notch 81' formed therein for engaging
a projection 82 formed on the bar 63. A stationary air cylinder 83,
having a piston rod 84 extending through an outer wall of the
sputtering apparatus, is provided for operating the latch 81. A
member 86 is mounted on the piston rod 84 and is provided with a
projection 86' for engaging an arm 87 extending from the latch 81.
The coupling and uncoupling of the bars 53 and 63 by operation of
the latch 81 to engage and disengage the projection 82 is similar
to the operation of the latch 71 and projection 72 described
above.
Thus, both bars 43 and 53 may be connected to the bar 63 by
operation of the latches 71 and 81. Workpieces may be then advanced
along the path defined by guide rails 42-42, 52-52, and 62-62 by
imparting reciprocating movement to the coupled bars 43, 53 and 63
through the rack 47 and pinion 48 mechanism. When the advancing
mechanism, i.e., the coupled bars 43, 53 and 63, is moved to the
left, as viewed in FIGS. 4 and 6, the workpiece-engaging fingers
44-44, 54-54 and 64-64 engage the edges of workpieces supported by
the guide rails 42-42, 52-52, and 62-62, and advance the workpieces
to the left. When the leftward stroke of the advancing mechanism is
completed, the motion of the coupled bars 43, 53 and 63 is
reversed.
Upon movement of the advancing mechanism to the right, the
workpiece-engaging fingers 44-44, 54-54 and 64-64 pivot into
horizontal positions to bypass the advanced workpieces. Thus, the
workpieces remain in their advanced positions while the advancing
mechanism is moved to the right, as viewed in FIGS. 4 and 6. When
the rightward stroke of the advancing mechanism is completed, the
fingers 44-44, 54-54, and 64-64 are moved into positions located
between the workpieces. The fingers 44-44, 54-54 and 64-64 are then
able to pivot into the spaces between adjacent workpieces by virtue
of gravitational forces exerted thereon. Then leftward movement may
be imparted to the advancing mechanism to repeat the advancing
sequence. In this manner, workpieces are conveyed in step-by-step
fashion along the conveyor 30.
ENTRANCE AND EXIT MAGAZINES
Referring to FIG. 2, the magazine M1 for receiving unprocessed
workpieces includes a plurality of vertical support members 20'-20'
having grooves or notches (FIG. 4) formed on the inner sides
thereof for receiving and supporting unprocessed workpieces. The
workpieces may be in the form of rectangular plates to which a thin
film of tantalum is to be applied. Alternatively, the support
members 20'-20' of the magazine M1 may be utilized to receive a
plurality of rectangular pallets upon which small workpieces, such
as ceramic bodies, may be supported during advancement through the
sputtering apparatus.
An elevating mechanism is provided for raising and lowering the
magazine M1 relative to the first section 32 of the conveyor 30. As
shown in FIGS. 2 and 4, the elevating mechanism may comprise a
screw which is threaded into an opening formed in the bottom of the
magazine M1. A motor (not illustrated) may be provided to turn the
screw thereby raising or lowering the magazine M1.
In preparing the apparatus for a sputtering operation, the magazine
M1 is initially located in a raised position relative to the
conveyor section 32. With the sealing device 26 operated to seal
the chamber 24, the entrance chamber 19 may be opened in order to
allow the magazine M1 to be loaded with unprocessed workpieces.
During the sputtering operation of the apparatus, the elevating
mechanism is operated to lower the magazine M1 to feed the
workpieces, one at a time, to the conveyor section 32.
At the opposite end of the sputtering machine, a second magazine M2
is located within the exit chamber 23. The magazine M2 also
includes a plurality of vertical support members 18-18 having
grooves or notches (FIG. 6) for receiving and supporting workpieces
which have been advanced through the sputtering apparatus. An
elevating mechanism, similar to that shown in FIG. 4, is provided
for raising and lowering the magazine M2 relative to the conveyor
section 33. Prior to the initiation of the sputtering operation,
the magazine M2, as indicated in FIG. 2, is located in a lowered
position relative to the conveyor section 32. During the
advancement of workpieces through the sputtering apparatus, the
magazine M2 is raised relative to the conveyor section 32 to
receive processed workpieces, one at a time, from the sputtering
section of the apparatus. When the sputtering operation is
completed, the magazine M2 is located in a raised position relative
to the conveyor section 32 and is completely filled with
workpieces. In order to facilitate the unloading of the magazine
M2, the sealing device 29 is operated to seal the exit chamber 23
from the cooling chamber 28. Then the exit chamber 23 may be opened
to allow the processed workpieces to be unloaded from the magazine
M2.
OPERATION
In the operation of the sputtering apparatus of the present
invention, the sputtering chamber 21 is maintained at a high level
of evacuation. The buffer chambers 24 and 28 are maintained at
levels of evacuation which are higher than the evacuation level of
the sputtering chamber 21, i.e., the pressures in the chambers 24
and 28 is less than the pressure in the chamber 21. A predetermined
mixture of nitrogen and argon is supplied to the sputtering chamber
21.
Since it is desirable to maintain the atmosphere in the sputtering
chamber 21 at a constant level of evacuation and to prevent
contamination of the nitrogen and argon mixture, it is necessary to
isolate the chambers 21, 24 and 28 from the ambient atmosphere at
all times. For this reason, the sealing devices 26 and 29 are
provided to prevent the ambient atmosphere from entering the
chambers 21, 24 and 28 when the entrance chamber 19 and the exit
chamber 23 are exposed to the ambient atmosphere.
Prior to initiation of a sputtering operation, the slides 26' and
29' of the sealing devices 26 and 29, respectively, are closed to
isolate the sputtering chamber 21 from the entrance chamber 19 and
the exit chamber 23. At this time, the entrance chamber 19 may be
opened to allow workpieces to be loaded into the magazine M1. The
exit chamber 23 may also be opened to allow processed workpieces to
be removed from the magazine M2.
At the beginning of a sputtering operation, the magazine M1 is
located in a raised position (FIG. 4) relative to the conveyor
section 32 and is completely filled with workpieces. The magazine
M2 is located in a lowered position relative to the conveyor
section 33 (FIG. 6).
The entrance chamber 19 and the exit chamber 23 are closed and then
evacuated until the level of pressure therein is equal to the
pressures maintained in the chambers 24 and 28. The temperature of
the workpieces is raised to a desired level by the heating elements
20-20. The slides 26' and 29' of the sealing devices 26 and 29,
respectively, are then opened. The entrance chamber 19 is thus in
communication with the chamber 24 and the exit chamber 23 is in
communication with the chamber 28.
At this point, the bar 43 is advanced to the left, as viewed in
FIG. 4, by rotating the pinion 48 in a counterclockwise direction.
When the bar 43 moves a sufficient distance to the left, the
projection 72 formed on the bar 43 moves into the notch 71' formed
in the latch 71 on the bar 63. The bars 43 and 63 are thus
connected by the latch 71. Upon continued rotation of the pinion 48
to move the bar 43 to the left, the bar 63 which is coupled to the
bar 43 also moves in this direction. When the bar 63 is moved a
sufficient distance, the projection 82 formed on the bar 63 moves
into the notch 81' formed in the latch 81 on the bar 53 (FIG. 6).
The bar 63 is thus connected to the bar 53 by the latch 81.
Since the bars 43, 53 and 63 are connected together, reciprocating
motion imparted to the bar 43 through the rack 47 and pinion 48 is
also transmitted to the bars 53 and 63. It is by virtue of this
reciprocating movement that workpieces are advanced from the
magazine M1 through the sputtering apparatus to the magazine M2.
During a leftward stroke of the workpiece advancing mechanism, the
fingers 44-44, 54-54, and 64-64 engage and advance workpieces along
the guide rails 42-42, 52-52 and 62-62 of the conveyor 30. The
fingers 44-44 mounted on the bar 43 advance workpieces from the
magazine M1 along the guide rails 42-42. After the workpieces are
advanced through the sealing device 26, the workpieces are received
by the guide rails 62-62 and are further advanced by the fingers
64-64 mounted on the reciprocating bar 63.
The workpieces are then advanced through the chamber 24 beneath the
heating element 22 which maintains the workpieces of the desired
temperature. Continued reciprocation of the bar 63 and the fingers
64-64 advances the workpieces through the sputtering chamber 21
past a sputtering cathode 25 which applies a thin film of tantalum
to the workpieces. Next, the coated workpieces are advanced through
the chamber 28, beneath a cooling panel 28', where initial cooling
of the workpieces takes place. Upon advancement through the second
sealing device 29, the workpieces are moved to the guide rails
52-52. The workpieces are then advanced along the guide rails 52-52
by the operation of the reciprocating bar 53 and the fingers 54-54
mounted thereon. The bar 53 and fingers 54-54 advance the
workpieces to the magazine M2.
During the reciprocation of the workpiece-advancing mechanism, the
magazine M1 is lowered by the elevating mechanism located in the
entrance chamber 19 to present workpieces, supported by the
magazine M1, one at a time, to the conveyor section 32. At the same
time, the magazine M2 is raised by the elevating mechanism located
in the exit chamber 23, by one step at a time, to permit workpieces
advanced along the conveyor section 33 to be received in the
magazine M2.
The reciprocation of the workpiece-advancing mechanism is continued
until all the workpieces originally located in the magazine M1 are
advanced through the sputtering apparatus and received in the
magazine M2. After the magazine M2 is completely filled with
workpieces, the bar 53 is returned to its initial position, as
shown in FIG. 6, and the air cylinder 83 is operated to pivot the
latch 81 to disconnect the bar 53 from the bar 63.
Then the bar 63 is returned to its initial position, as shown in
FIG. 4, to locate the arm 77 of the latch 71 adjacent to the member
76 supported by the piston rod 74. At this point, the air cylinder
73 is operated to pivot the latch 71 to disconnect the bar 43 from
the bar 63. Then the bar 43 is returned to its initial position
without affecting the position of the bar 63.
After the bars 43, 53 and 63 are disconnected and located in their
original positions, the slides 26' and 29' of the first and second
sealing devices 26 and 29, respectively, are closed to seal the
entrance chamber 19 from the chamber 24 and to seal the exit
chamber 23 from the chamber 28. The processed workpieces are then
allowed to cool in the exit chamber 23.
After the sealing devices 26 and 29 are closed and the workpieces
are cooled, the pressure in the exit chamber is raised to
atmospheric level and the exit chamber 23 is opened to permit the
processed workpieces to be unloaded from the magazine M2. It should
be noted that the magazine M2, at this time, is located in a raised
position relative to the conveyor section 33.
When the processed workpieces have been unloaded from the magazine
M2, the sputtering apparatus may then be prepared for a subsequent
sputtering operation. The magazine M2 is moved to its original
lowered position relative to the conveyor section 33. The exit
chamber 23 is closed. The entrance chamber 19 is opened and the
magazine M1 is moved to its initial raised position relative to the
conveyor section 32.
Then as described above, the magazine M1, may be loaded with
unprocessed workpieces to be advanced through the sputtering
apparatus. The entrance chamber 19 is then closed and the
sputtering operation described above may be repeated to advance the
workpieces from the magazine M1 through the sputtering apparatus to
the magazine M2.
In order to regulate the amount of tantalum deposited on the
workpieces in the sputtering chamber 21, the speed of reciprocation
of the workpiece-advancing mechanism is made variable by providing
a control device (not shown) for varying the speed of motor 49
(FIG. 4). By adjusting the speed of the motor 49 to a desired
value, the thickness of the thin film coating of tantalum applied
to the workpieces may be controlled.
In the operation of the sputtering apparatus, it may be desirable
to further limit communication between the sputtering chamber 21
and buffer chambers 24 and 28 by positioning workpieces within the
devices 50 and 50' located adjacent to chamber 21 for the time
during which the chambers 19 and 23 are exposed to the ambient
atmosphere. This result may be accomplished by removing two of the
fingers 64-64 from the bar 63, a first finger 64 which reciprocates
through the device 50 located at the exit side of chamber 24 and a
second finger 64 which reciprocates through the device 50' located
at the entrance side of chamber 28. With these two fingers 64-64
removed, the conveyor 30, in advancing the final two workpieces
from the magazine M1, will operate to advance the first of the
workpieces into the device 50' and the last of the workpieces into
the device 50. The workpieces will then remain in these positions
until another group of workpieces is loaded into the magazine M1
and advanced through the apparatus. It should be noted that the
final two workpieces in the magazine M1 will only be advanced as
far as the devices 50 and 50' located adjacent to the sputtering
chamber 21.
It should be noted that the above-described apparatus is merely
illustrative of the principles of the present invention. The
conveying system described herein is not limited to utilization
with an apparatus capable of performing only sputtering operations.
The system may be incorporated in any apparatus where it is
desirable to advance workpieces through a treating chamber which is
isolated from the ambient atmosphere. In addition, the structure of
the apparatus and its mode of operation may be modified by persons
having ordinary skill in the art without departing from the scope
of this invention.
* * * * *