Parylene deposition chamber including eccentric part tumbler

A deposition chamber for use in depositing vapors on substrates. The deposition chamber comprises a hollow outer containment vessel which defines a first longitudinal axis. Rotatably mounted within the containment vessel is a tumbler having first and second ends and an interior compartment for accommodating the substrates. The tumbler defines a second longitudinal axis which is angularly off-set relative to the first longitudinal axis. Disposed within the tumbler are vapor inlet and outlet ports, both of which communicate with the interior compartment. The rotation of the tumbler facilitates the reciprocal movement of substrates positioned within the interior compartment between the first and second ends of the tumbler.

FIELD OF THE INVENTION 
The present invention relates generally to a system for depositing 
condensation coatings on various substrates, and more particularly to an 
improved modular deposition chamber which includes an eccentric tumbler 
for facilitating the uniform deposition of para-xylylene polymers on 
substrates therewithin. 
BACKGROUND OF THE INVENTION 
Para-xylylene polymers are employed as coatings for various electronic 
components due to their desirable physical and electrical properties. One 
advantage of poly-para-xylylene coatings is that thin layers of such 
coatings are capable of exhibiting highly desirable physical and 
electrical properties. Because para-xylylene coatings are applied in very 
thin layers, heat tends to dissipate rapidly from the underlying 
components. Thus, the coated components cool down quickly and are less 
prone to temperature related degradation than similar components bearing 
other types of coatings. 
In further contrast to conventional polymer coatings, para-xylylenes are 
generally not prepolymerized prior to application on the coatable 
substrates. This is because the para-xylylene polymers are not given to 
simple extrusion, melting or molding as are many of the conventional 
thermoplastics. Additionally, because the para-xylylenes are generally 
insoluble in commonly used organic solvents, it is impractical to employ 
traditional solvent deposition techniques for applying poly-para-xylylene 
coatings. 
Accordingly, in most commercial applications, para-xylylene polymers are 
deposited on desired substrates by a pyrolytic deposition process known 
specifically as the "parylene process." Such process begins with the 
vaporization of a cyclic di-para-xylylene dimer. The dimer is 
pyrolytically cleaved at temperatures of about 400.degree. to 750.degree. 
C. to form a reactive para-xylylene monomer vapor. Thereafter, the 
reactive monomer vapor is transferred to a deposition chamber wherein the 
desired substrates are located. Within the deposition chamber, the 
reactive monomer vapor condenses upon the desired substrates to form a 
para-xylylene polymer or co-polymer film. 
Any monomer vapor which fails to condense within the deposition chamber is 
subsequently removed by a cold trap which is maintained at approximately 
-70.degree. C. 
The entire parylene process is generally carried out in a closed system 
under constant negative pressure. Such closed system may incorporate 
separate chambers for the (a) vaporization, (b) pyrolysis, and (c) 
deposition steps of the process, with such chambers being connected by way 
of appropriate plumbing or tubular connections. 
A primary consideration in the parylene deposition process is the 
achievement of uniform coating thickness on the desired substrates. Unlike 
conventional polymer coating systems, the condensation deposition of 
parylene coatings is capable of depositing even ultra-thin films without 
running or uneven areas resulting upon the substrates, provided that the 
monomer vapor is homogeneously and evenly distributed on the surface of 
the substrate. Thus, the design and functioning of the deposition chamber 
is critical to the achievement of uniform vapor distribution with 
resultant even coating deposition. Another important consideration in the 
parylene deposition process is the minimization of waste. Because of the 
high costs associated with parylene raw materials, there exists 
substantial economic motivation to preserve and conserve the parylene 
materials during the coating process. 
The parylene deposition process is conducted most efficiently when a 
relatively large number of substrates are simultaneously coated. However, 
parylene deposition chambers employed in the prior art are generally 
deficient in that they provide less than optimal coating uniformity due to 
an inferior distribution of substrates within the deposition chamber. In 
this respect, when large numbers of substrates are disposed within the 
deposition chamber, certain ones of the substrates often contact each 
other and/or portions of the inner wall of the deposition chamber. Since 
the substrates in the prior art deposition chambers are not tumbled or 
otherwise shifted during the deposition process, the coating is not 
applied to those surfaces of the substrates which are in contact with 
another substrate or the deposition chamber wall. The present invention 
overcomes this deficiency associated with prior art deposition chambers by 
providing a deposition chamber including an internal eccentric tumbler for 
facilitating the uniform and complete deposition of monomer vapor upon the 
substrates therewithin. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided a deposition 
chamber for use in depositing vapors on substrates. The deposition chamber 
comprises a hollow outer containment vessel which defines a first 
longitudinal axis. The containment vessel itself comprises a cylindrically 
configured housing having opposed ends and an inner surface. Rigidly 
attached to one end of the housing is a first end wall, while removably 
attached to the opposite end of the housing is a second end wall. 
In addition to the containment vessel, the deposition chamber comprises an 
eccentric tumbler which is rotatably mounted within the containment 
vessel. The tumbler includes first and second ends, and an interior 
compartment which accommodates the substrates. Additionally, the tumbler 
defines a second longitudinal axis which is angularly off-set relative to 
the first longitudinal axis when the tumbler is inserted into the 
containment vessel. In this respect, the removal of the second end wall 
from the housing allows the tumbler to be inserted into and removed from 
within the hollow interior of the containment vessel. Disposed within the 
tumbler are vapor inlet and outlet ports, each of which communicates with 
the interior compartment. Due to the second longitudinal axis being 
off-set relative to the first longitudinal axis, the rotation of the 
tumbler facilitates the reciprocal movement of the substrates positioned 
within the interior compartment between the first and second ends of the 
tumbler. Such reciprocal movement promotes the even coating of monomer 
vapor upon the substrates. The tumbler preferably rotates at a speed in 
the range of approximately 1 to 50 RPM's. 
In the preferred embodiment, the tumbler itself comprises a cylindrically 
configured sidewall. Enclosing one end of the sidewall is a first end 
plate, while enclosing the opposite end of the sidewall is a second end 
plate. The sidewall and the first and second end plates collectively 
define the interior compartment of the tumbler. The vapor inlet port is 
preferably disposed within the first end plate, with the vapor outlet port 
preferably being disposed within the second end plate. The tumbler further 
comprises a pair of bearing members or plates which are attached to 
respective ends of the sidewall. The first and second end plates are 
removably attached to respective ones of the bearing members for 
facilitating the loading and unloading of the interior compartment with 
the substrates. When the tumbler is inserted into the containment vessel, 
the peripheral edges of the bearing members are in movable engagement with 
the inner surface of the housing, thus facilitating the rotatable mounting 
of the tumbler within the containment vessel. 
In the preferred embodiment of the present invention, the deposition 
chamber is used in combination with a vapor inlet line which extends 
through the first end wall of the containment vessel. The vapor inlet line 
is inserted into the vapor inlet port and communicates with the interior 
compartment. In addition to the vapor inlet line, the deposition chamber 
is used in combination with a vapor outlet line which is fluidly connected 
to the housing and communicates with the vapor outlet port via an opening 
disposed within the bearing member having the second end plate attached 
thereto. Mechanically coupled to the tumbler, and in particular to the 
second end plate thereof, is a motor which, when activated, rotates the 
tumbler and thus facilitates the reciprocal movement of the substrates 
within the interior component. 
Further in accordance with the present invention, there is provided a 
method of depositing vapors on substrates. The method comprises the 
initial step of providing a deposition chamber which includes a 
containment vessel defining a first longitudinal axis, and a tumbler 
rotatably mounted within the containment vessel and defining a second 
longitudinal axis which is angularly off-set relative to the first 
longitudinal axis. The preferred method further comprises the step of 
loading the substrates into the interior compartment of the tumbler, and 
thereafter circulating vapors through the interior compartment. The 
tumbler is then rotated such that the substrates reciprocally move within 
the interior compartment thereof. The step of circulating the vapors 
through the interior compartment is preferably accomplished through the 
use of vapor inlet and outlet ports which communicate therewith. 
Additionally, the step of rotating the tumbler is preferably accomplished 
through the use of a motor mechanically coupled thereto.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings wherein the showings are for purposes of 
illustrating a preferred embodiment of the present invention only, and not 
for purposes of limiting the same, FIG. 1 perspectively illustrates a 
parylene deposition system 10 which includes the new and unique deposition 
chamber 12 constructed in accordance with the present invention. As seen 
in FIG. 1, the deposition system 10 is preferably of modular design, and 
includes a pyrolytic vapor generating module 14 and an attendant 
deposition chamber module 16. The pyrolytic vapor generating module 14 
comprises a cabinet-like enclosure 18 which includes a control panel 20. 
Disposed within the enclosure 18 of the vapor generating module 14 is a 
dimer vaporization chamber (not shown) into which parylene raw material is 
inserted via an associated entrance port. The vaporization chamber 
includes heating elements associated therewith, and provides a zone 
wherein a quantity of di-para-xylylene dimer is initially vaporized at 
elevated temperatures. Also disposed within the enclosure 18 is a 
pyrolysis chamber or pyrolizer (not shown) which is fluidly coupled to the 
vaporization chamber by appropriate tubular connections. The vaporized 
dimer exits the vaporization chamber and enters the pyrolizer wherein the 
dimer is pyrolyzed at temperatures of about 400.degree. to 750.degree. C. 
by heating elements associated with the pyrolizer so as to form the 
desired para-xylylene monomer vapor. Though also not shown, the vapor 
generating module 14 further houses a controller unit which controls the 
temperatures, conditions, valves, motors, pumps, etc., of the deposition 
system 10. 
The deposition chamber module 16 of the deposition system 10 itself 
comprises a base cabinet 22 to which the deposition chamber 12 is mounted. 
The deposition chamber module 16 further comprises a cold trap 24 which is 
fluidly coupled to the deposition chamber 12 by appropriate tubular 
connections which will be described in more detail below. The cold trap 24 
may be attached to or disposed within the base cabinet 22. Fluidly coupled 
to the cold trap 24 via a tubular connection 26 is a vacuum pump 28 which 
may also be attached to or disposed within the base cabinet 22. The vacuum 
pump 28 is used to maintain negative pressure within the deposition system 
10 as will described in more detail below. Though not shown, preferably 
disposed within the tubular connection 26 between the cold trap 24 and 
vacuum pump 28 is filter. 
As shown in FIGS. 1 and 2, the deposition chamber 12 includes a box-like 
motor housing 21 which is disposed on one end thereof and includes a motor 
30 mounted therewithin. The motor housing 21 includes two pairs of linear 
bearings 23 which are rigidly attached to the bottom thereof in opposed 
relation to each other. Each pair of the linear bearings 23 is slidably 
positioned upon a respective one of a pair of guide rods or rails 25 which 
are attached to the top surface of the base cabinet 22 via opposed pairs 
of mounts 27 so as to extend in spaced, generally parallel relation to 
each other. The attachment of the linear bearings 23 to the motor housing 
21 is preferably accomplished through the use of welds, though alternative 
attachment methods may be employed in the deposition chamber 12. The motor 
30 is used to facilitate the rotation of an eccentric component of the 
deposition chamber 12, as will also be described in more detail below. 
Referring now to FIGS. 2 and 3, the deposition chamber 12 of the present 
invention which is mounted to the base cabinet 22 of the deposition 
chamber module 16 is used to facilitate the deposition or coating of the 
monomer vapor upon substrates disposed therewithin. The deposition chamber 
12 comprises a stationary, hollow outer containment vessel 32 which 
defines a first longitudinal axis A1. The containment vessel 32 itself 
comprises a cylindrically configured housing 34 which defines a generally 
smooth inner surface 36. Rigidly attached to one end of the housing 34 via 
a weld W is a first end wall 38 which includes a lower, laterally 
extending flange portion 40. Attached to the opposite end of the housing 
34 is a second end wall 42. The second end wall 42 itself comprises a rim 
member 44 which is rigidly attached to the housing 34 via a weld W. The 
rim member 44, like the first end wall 38, includes a lower, laterally 
extending flange portion 46. The second end wall 42 further comprises a 
cover plate 48 which is removably attached to the rim member 44 via 
fasteners 50 such as bolts. As seen in FIG. 2, the motor housing 21 is 
itself attached to the outer surface of the cover plate 44 via fasteners 
51 such as bolts. The detachment of the cover plate 48 from the rim member 
44 provides access to the hollow interior of the containment vessel 32 for 
reasons which will be described in more detail below. As seen in FIGS. 1 
and 2, the flange portions 40, 46 of the first and second end walls 38, 42 
are used to facilitate the mounting of the containment vessel 32 to the 
top of the base cabinet 22 of the deposition chamber module 16. 
In addition to the containment vessel 32, the deposition chamber 12 
comprises an eccentric tumbler 52 which is rotatably mounted within the 
interior of the containment vessel 32. The tumbler 52 defines a first end 
54, a second end 56, and an interior compartment 58 which accommodates a 
plurality of substrates 60 to be coated within the parylene deposition 
system 10. The tumbler 52 further defines a second longitudinal axis A2 
which is angularly off-set relative to the first longitudinal axis A1 when 
the tumbler 52 is inserted into the containment vessel 32. 
In the preferred embodiment, the tumbler 52 comprises a cylindrically 
configured sidewall 62. Rigidly attached to respective ones of the opposed 
ends of the sidewall 62 is a pair of circularly configured bearing members 
or plates 76, each of which defines a peripheral edge. The attachment of 
the bearing members 76 to respective ones of the opposed ends of the 
sidewall 62 of the tumbler 52 is preferably facilitated through the use of 
welds W, though alternative attachment methods may also be employed in the 
deposition chamber 12. The overall diameter of each bearing member 76 is 
substantially equal to the diameter of the inner surface 36 of the housing 
34 of the containment vessel 32. Each of the bearing members 76 is 
preferably provided with a series of apertures or openings 80 disposed 
therein for reducing the weight thereof, and hence the overall weight of 
the tumbler 52. The openings 80 within the bearing member 76 disposed 
adjacent the second end 56 of the tumbler 52 are also used to provide a 
vapor flow path as will be discussed in more detail below. 
The tumbler 52 of the deposition chamber 12 further comprises a first end 
plate 64 which defines the first end 54 of the tumbler 52 and is removably 
attached to the adjacent bearing member 76 via fasteners 63 such as bolts. 
Removably attached to the other bearing member 76 via fasteners 65 such as 
bolts is a second end plate 66 which defines the second end 56 of the 
tumbler 52. The first and second end plates 64, 66 are identically 
configured, with the removable attachment of the first and second end 
plates 64, 66 to respective ones of the bearing members 76 via the 
fasteners 63, 65 facilitating the loading and unloading of the interior 
compartment 58 with the substrates 60. As will be recognized, the inner 
surfaces of the sidewall 62 and first and second end plates 64, 66 
collectively define the interior compartment 58 of the tumbler 52. Formed 
on the inner surface of the sidewall 62 in equidistantly spaced relation 
to each other are a plurality of elongate ribs 67 which extend 
longitudinally between the first and second end plates 64, 66 in generally 
parallel relation to the second longitudinal axis A2. As further seen in 
FIG. 2, the first and second end plates 64, 66, in addition to extending 
in generally parallel relation to each other, also extend in generally 
parallel relation to the first and second end walls 38, 42 of the 
containment vessel 32. 
Disposed within the first end plate 64 of the tumbler 52 is a vapor inlet 
port 70, while disposed within the second end plate 66 is a vapor outlet 
port 72. Both the vapor inlet port 70 and vapor outlet port 72 fluidly 
communicate with the interior compartment 58. Additionally, the vapor 
inlet and outlet ports 70, 72 are oriented within respective ones of the 
first and second end plates 64, 66 so as to extend along the first 
longitudinal axis A1 when the tumbler 52 is mounted within the containment 
vessel 32, rather than extending along the second longitudinal axis A2. 
As best seen in FIGS. 2 and 3, attached to the outer surface of the second 
end plate 66 and extending perpendicularly therefrom are two opposed pairs 
of elongate drive pins 74. The two pairs of drive pins 74 are disposed on 
opposite sides of and equidistantly spaced from the vapor outlet port 72 
such that the drive pins 74 of both pairs generally define respective ones 
of the four corner regions of a rectangularly configured region. The drive 
pins 74 are used to facilitate the mechanical coupling of the tumbler 52 
to the motor 30 mounted within the motor housing 21. Such coupling is 
facilitated by a drive shaft 100 which extends through and is rotatably 
mounted within the second end wall 42 of the containment vessel 32, and 
more particularly the cover plate 48 thereof. The rotatable mounting of 
the drive shaft 100 within the cover plate 48 is aided by a drive shaft 
seal 102 mounted to the outer surface of the cover plate 48. Extending 
perpendicularly from the end of the drive shaft 100 disposed within the 
interior of the containment vessel 32 is a coupling pin 104, the opposed 
ends of which extend between respective pairs of the drive pins 74 in the 
manner shown in phantom in FIG. 3. The structure formed by the combination 
of the drive shaft 100 and coupling pin 104 has a generally T-shaped 
configuration as seen in FIG. 2. Attached to the end of the drive shaft 
100 protruding from the containment vessel 32 and the drive shaft seal 102 
is a coupling 106 which is mechanically engaged to the output shaft 31 of 
the motor 30 via a chain 108. As will be recognized, due to the extension 
of the coupling pin 44 between each pair of drive pins 74, the rotation of 
drive shaft 100 via the motor 30 facilitates the concurrent rotation of 
the tumbler 52. The drive shaft seal 102 allows the drive shaft 100, and 
hence the coupling pin 104 and coupling 106 disposed on the opposed ends 
thereof, to rotate relative to the containment vessel 32. Importantly, the 
drive shaft 100 is oriented within the cover plate 48 of the containment 
vessel 32 so as to extend along the first longitudinal axis A1. 
As will be recognized, the bearing members 76 facilitate the rotatable 
mounting of the tumbler 52 within the containment vessel 32. In this 
respect, when the tumbler 52 is inserted into the hollow interior of the 
containment vessel 32, the peripheral edges of the bearing members 76 are 
in slidable engagement with the inner surface 36 of the housing 34, thus 
allowing the tumbler 52 to be easily rotated within the containment vessel 
32 by the motor 30. The bearing members 76 are preferably constructed of 
low friction plastic, such as ultra high density polyethylene to minimize 
frictional resistance to rotation. The insertion of the tumbler 52 into 
the containment vessel 32 and the removal of the tumbler 52 from 
therewithin is facilitated by the selective detachment of the cover plate 
48 of the second end wall 42 from the rim member 44 thereof. In this 
respect, subsequent to the removal of the fasteners 50, the motor housing 
21 (which is attached to the cover plate 48 via the fasteners 51) is slid 
along the guide rails 25 via the linear bearings 23 away from the housing 
34 of the containment vessel 32. Such movement causes the cover plate 48 
to be separated from the rim member 44 due to the attachment of the cover 
plate 48 to the motor housing 21, and further causes the coupling pin 104 
to be removed from between the drive pins 74 due to the drive shaft 100 
being rotatably mounted within the cover plate 48. The movement of the 
motor housing 21 to the distal ends of the guide rails 25 (i.e., the 
outermost mounts 27) provides sufficient space for the tumbler to be 
removed from within and re-inserted into the interior of the housing 34 of 
the containment vessel 32. 
As previously indicated, subsequent to the removal of the tumbler 52 from 
within the containment vessel 32 in the aforementioned manner, access to 
the interior compartment 58 thereof is facilitated by the removal of 
either the first or second end plates 64, 66 from a respective one of the 
bearing members 76. Such removal allows the substrates 60 to be loaded 
into and removed from within the interior compartment 58. Subsequent to 
the tumbler 52 being reinserted inserted into the interior of the 
containment vessel 32, the re-attachment of the cover plate 48 to the rim 
member 44 to enclose the containment vessel 32 is accomplished in the 
reverse order of the previously described detachment process. In this 
respect, the motor housing 21 is slid along the guide rails 25 until such 
time as the coupling pin 104 is re-inserted between the pairs of drive 
pins 74, and the cover plate 48 is abutted against the rim member 44. 
Thereafter, the fasteners 50 are used to re-attach the cover plate 48 to 
the rim member 44, thus facilitating the re-assembly of the second end 
wall 42 and the enclosure of the interior of the containment vessel 32. As 
will be recognized, the motor 30, cover plate 48, drive shaft 100, drive 
shaft seal 102, coupling pin 104, coupling 106 and chain 108 all move as a 
unit with the motor housing 21 along the guide rails 25. 
As best seen in FIG. 2, the deposition chamber 12 of the present invention 
is preferably used in combination with a tubular vapor inlet line 82 which 
extends through and is mounted within the first end wall 38 of the 
containment vessel 32. The vapor inlet line 82 defines a reduced diameter, 
nozzle-like inner end 84 which is inserted into the vapor inlet port 70 of 
the first end plate 64 and extends therethrough such that the vapor inlet 
line 82 communicates with the interior compartment 58 of the tumbler 52. 
The end of the vapor inlet line 82 opposite the inner end 84 includes a 
circularly configured connector flange 86 extending radially therefrom. 
The vapor inlet line 82 is mounted within the first end wall 38 so as to 
extend along the first longitudinal axis A1, thus causing the inner end 84 
to be coaxially aligned with the vapor inlet port 70. 
In the preferred embodiment, the tumbler 52 is rotatable relative to the 
vapor inlet line 82 which is maintained in fixed relation to the first end 
wall 38 of the containment vessel 32. In this respect, the insertion of 
the tumbler 52 into the interior of the containment vessel 32 is limited 
by the abutment of the first end plate 64 against the beveled shoulder 
defined between the inner end 84 of the vapor inlet line 82 and the 
remainder thereof. When the tumbler 52 is fully inserted into the interior 
of the containment vessel 32, the inner end 84 of the vapor inlet line 82 
is extended through the vapor inlet port 70 in the aforementioned manner, 
so as to communicate with the interior compartment 58 of the tumbler 52. 
The deposition chamber 12 is also preferably used in combination with a 
tubular vapor outlet line 88 which communicates with the housing 34 of the 
containment vessel 32 and fluidly couples the interior of the containment 
vessel 32 to the cold trap 24. The vapor outlet port 72 disposed within 
the second end plate 66 of the tumbler 52 communicates directly with the 
interior of the containment vessel 32. As seen in FIG. 1, the vapor inlet 
line 82, and in particular the connector flange 86 thereof, is connected 
to an inlet line 90 extending from the pyrolytic vapor generating module 
14 of the parylene deposition system 10. 
In the use of the parylene deposition system 10, the substrates 60 are 
initially loaded into the interior compartment 58 of the tumbler 52 by 
detaching the first end plate 64 or the second end plate 66 from a 
respective bearing member 76. Subsequent to the interior compartment 58 
being loaded with the substrates 60 and the first end plate 64 or second 
end plate 66 being re-attached to the bearing member 76, the tumbler 52 is 
inserted into the interior of the containment vessel 32. Access to the 
interior of the containment vessel 32 is facilitated by the removal of the 
cover plate 48 from the rim member 44 of the second end wall 42 by sliding 
the motor housing 21 along the guide rails 25 in the previously described 
manner. The tumbler 52 is inserted into the interior of the containment 
vessel 32 such that the inner end 84 of the vapor inlet line 82 is 
received into vapor inlet port 70. Such connection is facilitated simply 
by sliding the tumbler 52 longitudinally within the interior of the 
containment vessel 32 due to the vapor inlet line 82 and vapor inlet port 
70 being coaxially aligned with each other along the first longitudinal 
axis A1. When the inner end 84 is received into the vapor inlet port 70 in 
the aforementioned manner, the peripheral edges of the bearing members 76 
are in sliding contact with the inner surface 36 of the housing 34. After 
the tumbler 52 has been inserted into the interior of the containment 
vessel 32, the cover plate 48 is re-attached to the rim member 44 in the 
previously described manner, thus facilitating the enclosure of the 
interior of the containment vessel 32. As previously explained, the 
re-attachment of the cover plate 48 to the rim member 44 results in the 
re-insertion of the coupling pin 104 of the drive shaft 102 between the 
two pairs of drive pins 74 of the tumbler 52. 
After the tumbler 52 has been properly mounted within the containment 
vessel 32, a quantity of parylene dimer is introduced into the 
vaporization chamber of the pyrolytic vapor generating module 14 via its 
entrance port. After such introduction has occurred, the deposition 
process is initiated by activating the heating elements associated with 
the pyrolizer, the motor 30, and the vacuum pump 28. The heating elements 
of the pyrolizer are set to an operating temperature of approximately 
400.degree. to 700.degree. C., and preferably about 600.degree. C. When 
the set temperature of the heating elements of the pyrolizer has been 
reached and the required vacuum has been achieved by the vacuum pump 28, 
the heating elements of the vaporization chamber are activated to start 
the process of sublimation of the dimer. 
The activation of the vacuum pump 28 creates a negative system pressure 
which causes the parylene material to be drawn from the vaporization 
chamber into the pyrolizer via the tubular connections therebetween. As 
the vaporized dimer enters the pyrolizer, the heat provided by the heating 
elements associated therewith causes the dimer to be further pyrolyzed to 
form the desired para-xylylene-monomer. The vacuum created by the vacuum 
pump 28 causes the parylene vapor to be drawn into the interior 
compartment 58 of the tumbler 52 via the inlet line 90 and vapor inlet 
line 82. The vapor flows (i.e., circulates) through the interior 
compartment 58, and deposits upon the substrates 60 disposed therewithin. 
As the monomer vapor is circulated through the interior compartment 58, the 
tumbler 52 is rotated within the containment vessel 32 in the 
aforementioned manner via the activation of the motor 30. In the preferred 
embodiment, the motor 30 is adapted to rotate the tumbler 52 at a speed in 
the range of approximately 1 to 50 revolutions per minute. Importantly, 
due to the second longitudinal axis A2 of the tumbler 52 being angularly 
off-set relative to the first longitudinal axis A1 of the containment 
vessel 32, the rotation of the tumbler 52 causes the same to gyrate back 
and forth, thereby resulting in the reciprocal movement of the substrates 
60 between the first and second end plates 64, 66 in the manner shown in 
FIG. 4. The movement of the substrates 60 is aided by the ribs 67 disposed 
on the inner surface of the sidewall 62. The reciprocal movement of the 
substrates 60 within the interior compartment 58 as the monomer vapor 
circulates therethrough promotes the even and complete coating of the 
substrates 60 with the vapor. 
Any residual vapor not being deposited on the substrates 60 within the 
interior compartment 58 exits the tumbler 52 via the vapor outlet port 72. 
The vapor flows through the vapor outlet port 72 and into the enclosed 
interior of the containment vessel 32, and is subsequently drawn into the 
vapor outlet line 88 via the openings 80 disposed within the bearing 
member 76 having the second end plate 66 attached thereto. As seen in FIG. 
2, the vapor outlet line 88 is oriented in relative close proximity to 
this bearing member 76 of the tumbler 52. After passing through the outlet 
line 88, the vapor enters and circulates through the interior reservoir of 
the cold trap 24. The flow through the cold trap 24 causes the 
condensation and polymerization of residual vapors which were not coated 
upon the substrates 60 disposed within the interior compartment 58 of the 
tumbler 52. The vapor is then drawn from within the interior reservoir of 
the cold trap 24 through the tubular connection 26 and into the filter 
therewithin wherein any remaining vapor is removed from the air stream. In 
this respect, the filter prevents any parylene from condensing within the 
vacuum pump 28. Thereafter, the air stream is circulated through the 
vacuum pump 28 and subsequently vented to the exterior of the deposition 
chamber module 16. 
Additional modifications and improvements of the present invention may also 
be apparent to those of ordinary skill in the art. Thus, the particular 
combination of parts described and illustrated herein is intended to 
represent only one embodiment of the present invention, and is not 
intended to serve as limitations of alternative devices within the spirit 
and scope of the invention.