U.S. patent number 3,785,046 [Application Number 05/017,157] was granted by the patent office on 1974-01-15 for thin film coils and method and apparatus for making the same.
This patent grant is currently assigned to Hull Corporation. Invention is credited to Thomas A. Jennings.
United States Patent |
3,785,046 |
Jennings |
January 15, 1974 |
THIN FILM COILS AND METHOD AND APPARATUS FOR MAKING THE SAME
Abstract
Thin film inductance coils, separately or in transformer
combinations, are made by depositing on a substrate from vapor
sources directed through selected apertured masks, superimposed
layers of alternate films of electrically conductive metal and
electrical insulating material in successive segments of each of a
plurality of coil turns.
Inventors: |
Jennings; Thomas A. (Sutton,
Coldfield, EN) |
Assignee: |
Hull Corporation (Hatboro,
PA)
|
Family
ID: |
21781041 |
Appl.
No.: |
05/017,157 |
Filed: |
March 6, 1970 |
Current U.S.
Class: |
29/602.1;
118/504; 336/200 |
Current CPC
Class: |
H01F
17/0006 (20130101); Y10T 29/4902 (20150115) |
Current International
Class: |
H01F
17/00 (20060101); H01f 019/00 () |
Field of
Search: |
;29/602 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Custer, Jr.; Granville Y.
Attorney, Agent or Firm: Olson; Oliver D.
Claims
Having now described my invention and the manner in which it may be
used, I claim:
1. The method of making an inductance coil, comprising depositing
on a planar surface of a substrate in superimposed layers alternate
films of electrically conductive metal and electrical insulating
material, to form a plurality of superimposed coil turns of said
metal separated by interposed films of said insulating material,
each metal coil turn being formed by depositing successive segments
of said metal, with the leading end portion of each segment being
overlapped by the trailing end portion of the next succeeding
segment and the leading end portion of the last segment of each
turn overlapping the insulating material covering the trailing end
portion of the first segment of the underlying coil turn.
2. The method of claim 1 wherein the plurality of coils are
supported on the substrate in spaced, concentric relation.
3. The method of claim 1 wherein the films of metal and insulating
material are deposited from vapors thereof.
4. The method of claim 1 including
a. providing the substrate with a pair of spaced terminals,
b. depositing the first coil segment of metal in electrical contact
with one of said terminals, and
c. depositing the last coil segment of metal in electrical contact
with the other of said terminals.
5. The method of claim 1 including
a. depositing on a substrate a film of electrically conductive
metal in the form of a segment of a turn of a coil,
b. depositing over all but one end portion of said segment of metal
a film of electrical insulating material;
c. depositing on the substrate a film of electrically conductive
metal in the form of a second segment of said turn of a coil, with
one end of the second segment of metal in contact with the exposed
end of the first segment of metal and the opposite end of the
second segment of metal overlapping the film of insulating material
covering the first segment of metal,
d. depositing over all but one end portion of the second segment of
metal a film of electrical insulating material, and
e. repeating said deposition steps sequentially to form a
predetermined number of coil turns.
6. The method of claim 1 for making a transformer having a primary
coil and at least one secondary coil, the method including
a. the initial step of depositing on the substrate for each
secondary coil a film of magnetic metal in the form of a segment of
a core for coupling the primary coil and each secondary coil,
b. depositing over an intermediate portion of said metal core
segment a film of electrical insulating material,
c. depositing said successive segments of coil turns for the
primary coil and each secondary coil about and spaced from the
exposed end portions of the associated metal core segment, and
d. after forming the primary and secondary coils, depositing over
the last film of insulating material a film of magnetic metal in
the form of a second segment of said core in electrical contact
with the first segment of the core.
7. The method of claim 6 wherein the films of metal and insulating
material are deposited from vapors thereof.
Description
BACKGROUND OF THE INVENTION
This invention relates to inductance coils and more particularly to
thin film coils and to a method and apparatus for making them.
In the present state of micro circuit technology, interconnections
between chips are made by welding, soldering, or mechanical
fastening of metal wires or ribbons. It is generally recognized
that such forms of connections represent significant sources of
circuit failures. The present invention contemplates minimizing
such problems and providing other advantages by the use of thin
film inductance coils. For example, such coils afford the
introduction of inductor components into micro-circuitry. Still
further, by appropriate combination of coils the provision of
strong and dependable interconnections, transformers and switches
are made available.
Thin film coils have been made experimentally heretofore by
directing vapors of metal and insulating material through separate
apertures onto a rotating substrate to form a continuous coil of a
desired number of turns. This procedure imposes certain significant
structural limitations on the coils produced thereby. For example,
only one coil may be produced at one time. Moreover, the coils must
of necessity be circular in shape and therefore the inside area
defined by the coil constitutes a significant waste of valuable
substrate surface. Still further, the procedure limits the
deposition of insular material to but a single film, with
consequent high incidence of coil failure due to electrical
shorting between turns. In addition the procedure does not
accommodate the making of multiple coils and coupling cores and
therefore cannot be employed for the fabrication of
transformers.
SUMMARY OF THE INVENTION
In its basic concept the present invention provides for the
production of coils in which each of a plurality of turns of
superimposed layers of conductor metal and insulating material is
formed in successive interconnected segments.
It is by virtue of the foregoing basic concept that the principle
objective of this invention is achieved; namely, to overcome the
above enumerated disadvantages associated with micro-circuit
technology and with prior thin film coils.
Another important object of this invention is to provide a method
and apparatus by which coils may be formed with a plurality of
concentric coils of any desired shape, size and number of
turns.
Still another important object of this invention is to provide a
method and apparatus by which coils may be provided with multiple
layers of insulating material between conductor metal turns to
insure proper insulation.
A further object of this invention is to provide a method and
apparatus by which multiple coils may be formed simultaneously on a
single substrate to form transformers of various types and
configurations.
A still further important object of this invention is to provide a
simplified method and apparatus by which to produce coils and
transformers of high quality at minimum cost.
The foregoing and other objects and advantages of this invention
will appear from the foregoing detailed description taken in
connection with the accompanying drawings of preferred
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary, foreshortened vertical elevation, partly
in section, showing in some what schematic form apparatus embodying
the features of this invention.
FIG. 2 is a sectional view taken along the lines 2--2 in FIG.
1.
FIGS. 3-7 are plan views of various apertured masks for use in
fabricating an inductance coil.
FIGS. 8-14 are plan views illustrating the sequential steps in
fabricating an inductance coil by use of the masks illustrated in
FIGS. 3-7.
FIG. 15 is a plan view showing a plurality of concentric coils
mounted on a single substrate.
FIG. 16 is a vertical section illustrating a transformer
constructed from two inductance coils of FIG. 14.
FIGS. 17-23 are plan views of various apertured masks for use in
fabricating a multiple secondary transformer.
FIGS. 24-31 are plan views illustrating the sequential steps in
fabricating a multiple secondary transformer by use of the masks
illustrated in FIGS. 17-23.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2 of the drawings, the apparatus includes
a housing adapted to be evacuated. In the embodiment illustrated
this housing comprises a base 10 and a bell jar 12, preferably
transparent, supported removably thereon. A seal 14 is interposed
between the base and bell jar to provide a vacuum tight seal, as
will be understood. A conduit 16 extends through the base for
connection to a vacuum pump (not shown) for evacuating the
housing.
A supporting framework, including sub-base 18 and spaced vertical
posts 20, is mounted on the base within the housing. The upper
inturned ends of the posts mount a substrate heater unit 22 and
underlying substrate support 24 for a substrate 26. The substrate
is secured removably to the support by spaced clamps 28, although
other conventional means such as set screws, spring clips, or other
suitable form of retainer may be employed.
The heater unit is provided for heating the substrate support and
hence the substrate mounted thereon. In the embodiment illustrated
the heater unit includes an electric heater 30 connected to a
suitable source of electric potential by means of electrical
conductors 32 which extend through suitably sealed openings in the
base 10.
Means is provided in the housing for supplying vapors of
electrically conductive metal and electrical insulation material
selectively for deposition on a substrate. In the embodiment
illustrated such means comprise a pair of spaced crucibles 34 and
36 supported above the subbase. Each crucible is provided with
means for heating to vaporization the metal or insulating material
contained therein. Any of a variety of heating means may be
employed, such as an electron beam, a laser beam, an electric arc,
or an induction heater. Sputtering also may be employed as the
technique for vaporizing the materials. The source illustrated
merely for this explanation is an electric heater element 38
contained within each crucible and connected through a pair of
supporting bus bars 40 to a suitable source of electric potential,
by electrical conductors which extend through suitably sealed
openings in the base.
Electrically conductive metal to be deposited on a substrate may be
selected from a wide variety of metals such as gold, nickel,
aluminum, chromium, silver, tantalum and others. The form of the
metal selected is dependent in part upon the type of heating
employed to vaporize it. In the illustrated embodiment the heater
element is a wire of tungsten or other suitable metal heated by
high current, and the vaporizable metal is provided in a form
capable of being wrapped around the wire in crucible 34.
The electrical insulating material to be vaporized and deposited on
the substrate may be aluminum oxide, silicon dioxide, tantalum
pentoxide and various other oxides well known in the art for their
dielectric properties. In the embodiment illustrated the material
is placed in the crucible 36 for heating by the resistance wire
heater.
The substrate 26 preferably is made of the same dielectric material
as the electrical insulating material in order to minimize
differences in thermal expansion. However, it will be recognized
that the substrate may be made of other suitable materials.
It will be understood that vapors of the materials in the crucibles
progress through the evacuated space of the housing along optical
paths between the crucibles and substrate. Accordingly, means is
provided for intercepting said optical paths selectively to prevent
the passage of one or both of the vapors from the associated
crucibles to the substrate. In the embodiment illustrated such
means is provided by a shield plate 42 which is supported in
horizontal position above the crucibles by means of an operating
rod 44. This rod extends downward through a suitably sealed opening
in the base. The lower end of the rod projecting downward from the
base provides a handle by which the rod may be rotated on its
vertical axis. By this means the shield plate may be swung on said
vertical axis to intercept or expose the optical path between the
substrate and each of the crucibles.
In accordance with the present invention an inductance coil is
fabricated by depositing on a substrate, in superimposed layers,
alternate films of electrically conductive metal and electrical
insulating material in successive segments of each of a plurality
of coil turns. Accordingly, means is provided for directing the
vaporized materials onto the substrate in predetermined patterns to
produce said successive segments. In the embodiment illustrated
this means is provided by a plurality of apertured masks which are
described more fully hereinafter. Each mask is mounted, preferably
removably, on a mask holder for movement between a retracted
position away from the substrate and an operative position
interposed between the substrate and the crucibles.
In the embodiment illustrated, mask holders are disposed about the
substrate at 90.degree. intervals. In order to accommodate up to
eight different masks, the mask holders are arranged in cooperating
pairs, as best illustrated in FIG. 1. Thus, both mask holders 46
and 48 of a pair are mounted for pivotal movement on a common pivot
shaft 50 supported by bearing tabs 52 extending laterally from the
substrate support 24. A projecting arm 54 on each holder is
connected pivotally through a link 56 to the upper end of an
operating rod 58. The rod extends downward slidably through a guide
opening in a lateral bracket 60 on a vertical post 20, thence
through an aligned guide opening in the sub-base 18, and thence
through a suitably sealed opening in the base 10. The lower end of
the rod provides a handle by which it may be moved vertically to
effect movement of the associated mask holder between the
aforementioned retracted and operative positions of the supported
mask.
The arrangement of cooperating pairs of mask holders allows the
mask carried by the inner holder 46 to be moved between retracted
and operative positions independently of the mask carried by the
associated outer holder 48. Movement of the mask carried by the
outer holder to its operative position results in simultaneous
movement of the associated inner mask to operative position
interposed between the outer mask and the substrate 26. The
cooperation between the inner and outer masks of an associated pair
of holders is explained more fully hereinafter.
It will be understood that if the number of masks required for the
fabrication of a particular type of coil or transformer are fewer
than eight, each unused mask holder has a sufficiently large
opening 62 so as not to interfere with the proper function of the
mask carried by the associated holder. Alternatively, the number of
mask holders may be reduced correspondingly, as will be
understood.
The method of this invention and the operation of the apparatus
described hereinbefore as best explained by the following
descriptions of the fabrication of inductance coils and
transformers.
Considering first the fabrication of a single inductance coil,
reference is made to FIGS. 3-14.
The substrate 26 first is provided with a pair of spaced
electrically conductive terminals 64 and 66 (FIG. 8). These may be
formed by vapor deposition, by printed circuit technique, or by any
other suitable means. One of the terminals, for example terminal
64, extends farther inward from the margin of the substrate than
the other terminal 66, as illustrated.
The substrate is mounted in the substrate support 24, the bell jar
12 is mounted in place on the base 10 and the housing then is
evacuated to at least 1 .times. 10.sup.-.sup.4 torr. The substrate
then is heated by heater 30 to its appropriate deposition
temperature.
The first deposition on the substrate is a film of electrically
conductive metal to form the first segment of the first turn of the
coil, Accordingly, the mask 68 illustrated in FIG. 3 is moved to
operative position adjacent the substrate. With the shield 42
positioned across both crucibles, the heater 38 for the crucible 34
containing the vaporizable metal is adjusted to the desired
conductor metal deposition rate, the metal in the crucible is
outgassed and the shield then is moved out of the optical path
between the crucible 34 and the substrate 26. The metal vapors pass
through the opening 70 in the mask 68 and are deposited on the
substrate to form the segment 72 illustrated in FIG. 9. It is to be
noted that this segment is in electrical contact with the longer
terminal 64.
When the desired thickness of the conductor segment is attained,
for example about 1000 Angstroms, the shield 42 is moved back to
cover both crucibles, the mask 68 is retracted and the mask 74
illustrated in FIG. 4 is moved to operative position. The
insulating material in the crucible 36 is outgassed, the heater 38
associated therewith is adjusted to proper operating temperature to
provide the desired deposition rate, and the shield then moved out
of the optical path between the crucible 36 and the substrate 26.
The vapors of insulation material pass through the aperture 76 in
the mask 74 and deposit on the substrate to form the insulation
segment 78 illustrated in FIG. 10. It is to be noted that this
segment of insulating material covers all but one end portion 72'
of the underlying conductor segment 72.
Although the film of insulating material may be provided as a
single layer of predetermined thickness, the preferred procedure is
as follows: The deposition is stopped when about one half of the
total desired film thickness is deposited, and the pressure of the
vacuum system is increased to about 100 milli-torr by such means as
a variable leak valve. Gasses such as argon and nitrogen may be
used to backfill the vacuum chamber. The leak valve then is turned
off and the pressure is allowed to return to its original operating
level, after which the second half of the insulator film is
deposited.
After the insulator film has been deposited, for example to a total
thickness of about 1000 Angstroms, the shield 42 is returned over
the crucible 36 and the mask 74 is retracted. The pair of masks 80
and 82 illustrated in FIGS. 5 and 6 then are moved to operative
position, with the mask 80 interposed between the mask 82 and the
substrate 26. This is achieved by mounting masks 80 and 82 on
holders 46 and 48, respectively, of a pair. The shield now is moved
to expose the conductive metal in the crucible 34, whereupon metal
vapors are caused to pass first through the aperture 84 in mask 82
and then through the aperture 86 in mask 80. The vapors deposit on
the substrate to form the second segment 88 of the first turn of
the inductance coil, as illustrated in FIG. 11. It is to be noted
that one end of this second segment overlaps the exposed end
portion 72' of the first segment, and therefore is in electrical
contact therewith, and that the opposite end of the second segment
overlaps a portion of the underlying first segment 78 of insulating
material. It is to be noted further that the use of the mask 82
illustrated in FIG. 6 in combination with the mask 80 illustrated
in FIG. 5 has caused the lower portion 86' of the aperture 86 of
the mask 80 to be covered. Thus, conductive metal vapors have not
been allowed to deposit on the substrate in contact with the
shorter terminal 66.
In the embodiment illustrated, each coil turn is made of two
segments. It will be apparent that each turn may be made of more
than two segments, by provision of appropriate numbers of masks
provided with appropriately shaped apertures.
When the desired thickness of conductor metal has been deposited to
complete the second segment 88 of the first turn, the shield 42 is
returned to cover the crucible 34, the masks 80 and 82 are
retracted and the mask 90 illustrated in FIG. 7 is moved to
operative position. The shield then is moved to expose the crucible
36, thereby allowing the passage of insulation material vapors
through the aperture 92 in mask 90, for depositing the second
segment 94 of insulating material, as illustrated in FIG. 12. This
film of insulating material overlaps the first segment 78 of
insulating material and all but one end portion 88' of the second
segment 88 of conductive metal, as illustrated.
The foregoing deposition steps are repeated sequentially until all
but the last of the desired number of coil turns and insulator
films have been deposited in superimposed layers. When the first
segment of the last turn of conductive metal and insulating
material have been deposited, in the manner illustrated in FIG. 10,
the second segment 98 of the last turn of conductive metal is
deposited by using only the mask 80 illustrated in FIG. 5, i.e.
without combination with the mask 82 illustrated in FIG. 6. The
deposition of the conductive metal segment 98 resulting therefrom
is illustrated in FIG. 13. It can be seen that this last segment of
conductive metal includes the extension 98' which makes electrical
contact with the shorter terminal 66. Thereafter, the final
insulating segments are deposited by sequential use of the masks 74
and 90 illustrated in FIGS. 4 and 7 to complete the coil, as shown
in FIG. 14.
It should be noted here that the foregoing method and apparatus are
capable of producing inductance coils of any desired shape, size
and number of turns. Although the coil configuration illustrated in
FIGS. 3-14 is rectangular, it may be circular, triangular, square,
or any other shape desired. The size of the coil may be less than
1/8 inch in its longest dimension, while a few thousandths of an
inch total thickness accommodates several thousand coil turns.
Another advantage attending the case of apertured masks for the
deposition of coil segments, resides in the ability to provide
masks for producing simultaneously a plurality of concentric coils
on a single substrate. Such a multiple coil arrangement is
illustrated in FIG. 15, wherein there is shown three concentric
coils supported on a single substrate.
Although the coils are illustrated as being interconnected to form
a single coil of the sum of all three coil turns, it will be
understood that the coils may be separated, each with its own pair
of terminals, to provide a plurality of separate coils on a single
substrate. These separate coils may be produced simultaneously by
masks provided with multiple apertures.
Coils produced in the manner described hereinbefore may be utilized
as inductor components in micro-circuitry. On the other hand, two
or more such coils may be combined to provide a transformer. One
such form of transformer is illustrated in FIG. 16. Therein is
shown two such coils 100 and 102 arranged in spaced apart relation
with their respective substrates 104 and 106 secured to a support
108 of dielectric material. Underlying this support is
ferro-magnetic plate 110. Aligned openings are provided through the
substrates, support and plate in registry with the central openings
defined by the coils. A bar 112 of ferro magnetic material supports
a pair of spaced legs 114 of similar material which extend
removably through the aligned openings and make physical contact
with the underlying plate 110. The plate, bar and legs thus form a
ferro-magnetic core which couples the coils together. One coil is
usable as a primary winding of a transformer and the other as a
secondary. Since the assembly of bar 112 and legs 114 is removable,
the transformer may serve the function of a switch. It will be
apparent to those skilled in the art that if the plate 110, bar 112
and legs 114 are formed as a fixed, continuous ferro-magnetic loop
coupling the coils 100 and 102 together, the resulting transformer
may serve as an electrical interconnection between the substrate
104 and 106.
FIGS. 17-31 illustrate the masks and method steps by which to
fabricate a transformer having a permanent core which couples to a
primary winding a step-down secondary winding and another secondary
winding having the same number of turns as the primary. In
fabricating this transformer, the substrate 120 first is provided
(FIG. 24) with a pair of electrically conductive terminals 122 and
124 for the primary winding, a pair of terminals 126 and 128 for
the step-down secondary winding and a pair of terminals 130 and 132
for the equal turns secondary winding. The substrate also is
provided with magnetic core segments 134 and 136 for coupling the
primary winding to the secondary windings. The intermediate portion
of each of these core segments is overlaid with a film 138 of
electrical insulating material such that the opposite end portions
of the core segment are exposed. The substrate 120 then is mounted
in the substrate support.
The first deposition on the substrate is provided by moving the
pair of masks 140 and 142 illustrated in FIGS. 17 and 18 into
operative position across the substrate, with mask 142 interposed
between mask 140 and the substrate. It is to be noted that the
aperture 144 of mask 142 does not interfere with, or modify, the
apertures 146, 148 and 150 of mask 140. However, it is interposed
between mask 142 and the substrate because it is used by itself in
a later deposition step. Vapors of electrically conductive metal
then are directed through the apertures of mask 140, in the manner
previously described. This results in the deposition of the first
electrically conductive metal segments 152, 154 and 156 of the
first turns of all three windings, as illustrated in broken lines
in FIG. 25. The masks 140 and 142 then are retracted.
It is to be noted that these first segments of electrically
conductive metal are deposited in electrical contact with one of
the associated pair of terminals, for example terminals 122, 126
and 130, respectively, whereby to provide electrical connection at
one end of each coil. It is to be noted further, by comparison of
FIGS. 24 and 25, that these first segments are spaced from the
exposed ends of the core segments 134 and 136 by depositing a
portion of the segments on the intermediate layer 138 of insulating
material and the remainder on the substrate 120.
The second deposition is provided by moving the mask 158
illustrated in FIG. 20 to operative position and directing vapors
of insulating material through its apertures 160, 162 and 164 onto
the substrate. This results in the deposition of the first segments
166, 168 and 170 of insulating material over the respective first
segments 152, 154 and 156 of conductor metal, as illustrated in
FIG. 25. It is to be noted that each of these insulator segments
covers all but one end portion of the associated underlying segment
of conductor metal. The mask 158 then is retracted.
The third deposition is provided by moving the masks 172 and 174
illustrated in FIGS. 21 and 22 into operative position, with mask
174 interposed between mask 172 and the substrate 120. The aperture
176 of mask 172 serves to expose all of the apertures 178, 180 and
182 of mask 174 except the projecting portions 178', 180' and 182'
thereof. Vapors of conductive metal then are directed through the
mask apertures onto the substrate to provide the deposition of the
second segments 184, 186 and 188 of the first turns of conductive
metal for the coils, as illustrated in FIG. 26. It is to be noted,
by comparison of FIGS. 25 and 26, that one end of each of these
second segments overlaps the exposed end portion of the associated
first segment of conductive metal and that the opposite end portion
of the second segment overlaps the corresponding end portion of the
first segment of insulating material.
The fourth deposition is provided by moving the mask 190
illustrated in FIG. 23 into operative position and directing vapors
of insulating material through its apertures 192, 194 and 196 onto
the substrate. This provides the second segments 198, 200 and 202
of insulating material for the first turn of each coil, as
illustrated in FIG. 26. These insulating segments cover all but one
end portion of the underlying second segments of conductor metal,
as illustrated. Thus, the first complete turn of each coil is
completed.
The foregoing four depositions are repeated sequentially until
there has been deposited on the substrate the desired number of
coil turns for the step-down secondary winding 204 (FIG. 29).
The fifth deposition is provided by moving the masks 140 and 142
illustrated in FIGS. 17 and 18 into operative position and
directing therethrough vapors of electrically conductive metal.
This provides the deposition of the first segments 206 and 208
(FIG. 27) of conductive metal for the next subsequent turn of the
primary winding 210 and equal turns secondary winding 212,
respectively (FIG. 29). It also provides a deposition of a
corresponding segment 214 of conductive metal overlaying the
step-down secondary winding 204, but this does not constitute an
additional winding, as will become apparent.
The sixth deposition is provided by moving the masks 216 and 158
illustrated in FIGS. 19 and 20 into operative position with the
mask 158 interposed between mask 216 and the substrate. Vapors of
insulating material then are directed through the masks to provide
the deposition of segments 218 and 220 illustrated in FIG. 27. It
is to be noted that these insulating film segments cover only the
respective conductive metal segments 206 and 208 associated with
the primary winding and equal turns secondary winding. This is
evident from FIGS. 19 and 20 wherein the apertures 222 and 224 are
shown to register only with apertures 160 and 164 of mask 158 and
no aperture is provided in mask 216 for registry with aperture 162
of mask 158. Accordingly, mask 216 has prevented deposition of
insulating material over the segment 214 of conductive metal
deposited over the step-down secondary winding.
The seventh deposition is provided by moving the masks 172 and 174
illustrated in FIGS. 21 and 22 into operative position and
directing vapors of conductive metal therethrough. The depositions
thus provided are the same as those illustrated in FIG. 26.
The eighth deposition is provided by moving the mask 190
illustrated in FIG. 23 into operative position and directing vapors
of insulating material therethrough. These depositions of
insulating films also are the same as those illustrated in FIG.
26.
The foregoing fifth, sixth, seventh and eighth depositions are
repeated sequentially until there has been deposited all but the
last one of the desired number of turns for the primary winding 210
and the equal turns secondary winding 212. The first segment of
conductive metal and insulating material for the last turn then are
provided by repeating the fifth and sixth depositions.
The ninth deposition is provided by moving the mask 174 illustrated
in FIG. 22 into operative position while retaining the associated
mask 172 illustrated in FIG. 21 in retracted position. Vapors of
conductive metal then are directed through the mask apertures to
provide deposition of the conductive metal segments 226, 228 and
230 illustrated in FIG. 28. It is to be noted that each of these
segments includes an extension which makes electrical contact with
the associated second terminal 124, 128 and 132, respectively, of
each pair. Each pair of terminals thus provides electrical
connection to the opposite ends of the associated coil.
The tenth and eleventh depositions are provided by moving the masks
158 and 190 illustrated in FIGS. 20 and 23 sequentially into
operative position and directing vapors of insulating material
therethrough. These depositions provide an insulating film 232
covering the completed windings, as illustrated in FIG. 29.
The twelfth deposition is provided by moving the mask 172
illustrated in FIG. 21 into operative position while retaining the
mask 174 illustrated in FIG. 22 in retracted position. Vapors of
magnetic metal then are directed through the mask to provide the
deposition 234 illustrated in FIG. 30. This deposition completes
the transformer, as shown in FIG. 31. It is to be noted that this
deposition constitutes a second segment of the transformer core and
it makes electrical contact with the exposed opposite ends of the
underlying first segments 134 and 136 of the core to provide
continuous loops of metal which couple together the primary winding
210 and each of the secondary windings 204 and 212.
It will be apparent from the foregoing that various other
transformer configurations may be fabricated, as desired. For
example, additional secondary windings may be included by
appropriate provision at different masks. Step-up secondary coils
may be provided by providing masks to shield the other windings
from additional depositions. By omitting the core segments and
providing removable cores, in the manner illustrated in FIG. 16,
such multiple secondary transformers also may be employed as
switches.
The foregoing and many other variations may be made within a wide
range of coil shapes and sizes, as will be understood. As an
illustration, the double secondary transformer illustrated in FIG.
31 may be fabricated on a substrate that is one-half inch square.
Smaller or larger substrates may be employed, as will be
apparent.
It will be further apparent to those skilled in the art that
various other changes may be made in the size, shape, number and
arrangement of parts of the components of the coils, transformers
and apparatus, as well as the number, type and arrangement of
method steps described hereinbefore, without departing from the
spirit of this invention.
* * * * *