Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-03-24
2001-10-09
Young, Lee (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S874000, C336S096000, C336S200000, C336S196000
Reexamination Certificate
active
06298544
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of fabricating a high frequency thin film coil element, and more particularly, to a method with high quality and low production cost.
2. Description of the Prior Art
As the growth of radio communication is so rapid that almost completely takes over the position of wired communication, the frequencies are also rising higher and higher, and the requirements for coils with good high frequency: characteristic, such as high accuracy with minimum errors, high Q quality, low resistance, and very high self-resonance frequency . . . etc. increase day after day. However, most of the coil manufactures in this field have been able to contribute to meet the above requirements by providing high frequency coils of excellent quality.
Now, the fabricating methods of two of the most commonly used high frequency coil elements are described briefly hereinafter:
1. Thin film laminated, spirally loop shaped high frequency coil element (see FIGS.
1
A-
1
U:
The steps of fabricating this type of coil element comprise: forming a metallic conductor film
101
(
FIGS. 1C
,
1
D) by a proper deposition process on both surfaces of a ceramic or glass substrate
100
(
FIGS. 1A
,
1
B) which is cut to form a minimum unit chip; then perform the first lay spiral segment circuit and conducting pad Ly lithography technologies; the other surface also performing the similar processes as those of the first surface to form a spirally looped main body, and then reserving a connecting terminal
103
(
FIGS. 1E
,
1
F). In each of the steps mentioned above, electro plated layers
104
,
105
(
FIGS. 1G
,
1
H) are formed on conductor surfaces of the main body for increasing the thickness of the conductor thereby reducing the resistance and improving low resistance characteristic. Then afterward, selecting a certain material with low dielectric constant to form an insulation protecting layer
106
on the main body surface, and reserving the space for the conductor terminal and the space for a connecting hole
107
at the center of the spirally looped main body as well for the purpose of forming a connecting film thereof to complete fabrication of a first loop coil element after connection of the connecting film to the other terminal. Again, similar to the step of fabricating the first layer of spirally looped conductor shown in
FIG. 1E
, a second conductor film
108
and an electro plated layer
109
are formed on the protecting layer
106
so as to connect the central point of spiral loop to the other terminal thereby forming a complete coil (FIGS.
1
H-
1
N). Next, covering the spirally looped main body with a protecting layer
110
(
FIGS. 1P
,
1
Q), and attaching a lead wire
111
for the terminal on each of both sides of the substrate between the two poles after cutting the substrate thereby to complete fabrication of a basic coil element (
FIGS. 1R
,
1
S). Finally, the coil element is electro plated, and an interface layer is attached to the lead wire according to various usages so the all fabrication steps come to the end (FIGS. IT,
1
U).
As it can be seen from the above description, such fabrication steps are quite complicated and expensive.
2. Metallic conductor (copper) wire wound type high frequency coil element (refer to FIGS.
2
A~
2
C):
This type of coil element is fabricated on a specially shaped, single unit ceramic substrate
201
. The required terminal
202
for connecting with conductor is already prepared thereon. A varnished insulation copper wire
203
is wound around the ceramic substrate
201
by means of a specially designed winding machine and the wire terminals
2004
at two ends are connected to a reserved position (FIG.
2
B). Finally, a cover layer
205
is applied to protect the coil thereby completing fabrication of a coil element (FIG.
2
C).
To shallowly think it seems that fabricating such a coil is so easy that the only thing to do is to wind the varnished insulation wires on the substrate, yet it involves several problems remaining unsolved, namely:
A. The cost for raw materials becomes high as a very specially made substrate is used.
B. Winding varnished insulation wires around the substrate by means of a specially designed winding machine results in high equipment cost but inefficient production speed.
C. Though the size of winding affects the coil characteristic greatly, the operation of winding machine can not effectively control the size of winding resulting in a poor yield rate, and finished products have to go through checking and classification procedures again.
As described above, the conventional methods of fabricating high frequency coils have a number of unsolved problems which result in high production cost and expensive product price which the customer has to suffer from.
Having determined to solve these problems, the inventor of the present invention has studied for a long time trying to find out if there by any possibility to develop a new product able to overcome the difficulties which the conventional products and technology encountered and finally succeeded in providing high frequency thin film coil element and method of fabricating the same which will now be disclosed herein.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide high frequency thin film coil element and method of fabricating the same which can sharply reduce the production cost and increase the performance quality of the product by simplifying and stabilizing the method of fabrication thereby enabling the customer to enjoy the use of low price, high quality products.
To achieve the above object, gist of the present invention is directed to provide a high frequency thin film coil element comprising a main coil body composed of a rod shaped ceramic substrate, a thin metallic film layer covering the ceramic substrate, a conductor layer covering the thin metallic film layer, and a plurality of notches being cut from the conductor layer down to the substrate thereon, interface layers for conductor terminals provided at two side of the main coil body; a protecting layer covering the main coil body; and an anti-oxidation layer being cut as the conductor layer sandwiched between the conductor layer and the protecting layer of the main coil body, and the method of fabricating the same.
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patent: 5598621 (1997-02-01), Littecke
patent: 5764126 (1998-06-01), Kanetaka et al.
patent: 5853558 (1998-12-01), Gray et al.
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patent: 6157283 (2000-12-01), Tsunemi
patent: 0238104 (1986-10-01), None
patent: 0265413 (1988-11-01), None
patent: 11346450 (1999-11-01), None
Dougherty & Troxell
Inpaq Technology Co. Ltd.
Trinh Minh
Young Lee
LandOfFree
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