U.S. patent application number 11/870182 was filed with the patent office on 2009-01-29 for circuit board structure with concave conductive cylinders and method for fabricating the same.
This patent application is currently assigned to UNIMICRON TECHNOLOGY CORP.. Invention is credited to Chih-Ming Chang, Shao-Chien Lee.
Application Number | 20090025210 11/870182 |
Document ID | / |
Family ID | 40293963 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090025210 |
Kind Code |
A1 |
Lee; Shao-Chien ; et
al. |
January 29, 2009 |
CIRCUIT BOARD STRUCTURE WITH CONCAVE CONDUCTIVE CYLINDERS AND
METHOD FOR FABRICATING THE SAME
Abstract
A method for fabricating a circuit board structure with concave
conductive cylinders is provided. Firstly, a conductive layer is
provided; a plurality of conductive cylinders are formed on a
surface of the conductive layer; a dielectric layer is formed on
the surface of the conductive layer with the conductive cylinders;
the tips of the conductive cylinders are exposed on a surface of
the dielectric layer far away from the conductive layer; removing
the exposed tips of the conductive cylinders such that the height
of the conductive cylinders is lower than the height of the
dielectric layer, and the conductive cylinders sunk into the
dielectric layer.
Inventors: |
Lee; Shao-Chien; (Taoyuan
County, TW) ; Chang; Chih-Ming; (Tinan City,
TW) |
Correspondence
Address: |
J C PATENTS, INC.
4 VENTURE, SUITE 250
IRVINE
CA
92618
US
|
Assignee: |
UNIMICRON TECHNOLOGY CORP.
Taoyuan
TW
|
Family ID: |
40293963 |
Appl. No.: |
11/870182 |
Filed: |
October 10, 2007 |
Current U.S.
Class: |
29/829 |
Current CPC
Class: |
H05K 1/113 20130101;
H05K 2201/09827 20130101; H05K 2201/0394 20130101; Y10T 29/49128
20150115; H05K 3/3457 20130101; H01K 3/10 20130101; H01L 23/5384
20130101; H01L 21/4853 20130101; H05K 3/06 20130101; Y10T 29/49124
20150115; Y10T 29/49165 20150115; H01L 23/49816 20130101; Y10T
29/49155 20150115; H05K 2203/0733 20130101; H01L 21/486 20130101;
H05K 3/4647 20130101; Y10T 29/49126 20150115; H01L 2924/0002
20130101; H05K 3/423 20130101; H05K 2201/09472 20130101; H01L
2924/00 20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
29/829 |
International
Class: |
H05K 3/00 20060101
H05K003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2007 |
TW |
96127050 |
Claims
1. A method for fabricating a circuit board structure with concave
conductive cylinders, comprising: providing a conductive layer;
forming a plurality of conductive cylinders on a surface of the
conductive layer; forming a dielectric layer on the surface of the
conductive layer; exposing the tips of the conductive cylinders on
a surface of the dielectric layer far away from the conductive
layer; and removing the exposed tips of the conductive cylinders,
so that the height of the conductive cylinders is relatively lower
than the dielectric layer and the conductive cylinders sunk into
the dielectric layer.
2. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 1, wherein the step of
forming the conductive cylinders comprises: partially etching the
conductive layer.
3. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 1, wherein the step of
forming the dielectric layer comprises: laminating or printing a
dielectric material on the surface of the conductive layer.
4. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 1, wherein the step of
removing the exposed tips of the conductive cylinders comprises
grinding or etching.
5. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 1, wherein after removing the
exposed tips of the conductive cylinders, further comprises:
disposing a solder material on the conductive cylinders sunk into
the dielectric layer, so as to rise the solder material above the
dielectric layer.
6. A method for fabricating a circuit board structure with concave
conductive cylinders, comprises: providing a conductive layer;
forming a dielectric layer on a surface of the conductive layer;
forming a plurality of vias in the dielectric layer, wherein the
vias expose the surface of the conductive layer; filling a
conductive material in the vias to form a plurality of conductive
cylinders on the surface of the conductive layer, so that the tips
of these conductive cylinders are exposed on a surface of the
dielectric layer far away from the conductive layer; and removing
the exposed tips of the conductive cylinders, so that the height of
the conductive cylinders is relatively lower than the dielectric
layer and the conductive cylinders sunk into the dielectric
layer.
7. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 6, wherein the step of
forming the dielectric layer comprises: laminating or printing a
dielectric material on the surface of the conductive layer.
8. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 6, wherein the method of
forming the vias comprises laser drilling.
9. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 6, wherein the method of
filling the conductive material in the vias includes printing and
filling, electroplating, sputtering or vapour deposition
method.
10. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 9, wherein the conductive
material filled in the vias comprise copper, copper paste, silver
paste or conductive polymeric material.
11. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 6, wherein the material
filled in these vias comprise copper, copper paste, silver paste or
conductive polymeric material.
12. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 6, wherein the steps of
removing the exposed tips of the conductive cylinders comprises
grinding or etching.
13. The method for fabricating a circuit board structure with
concave conductive cylinders of claim 6, wherein after removing the
exposed tips of the conductive cylinders, further comprises:
disposing a solder material on the conductive cylinders sunk into
the dielectric layer, so as to rise the solder material above the
dielectric layer.
14. A circuit board structure with concave conductive cylinders,
comprising: a conductive layer; a plurality of conductive
cylinders, formed on a surface of the conductive layer, and
electrically connected to the conductive layer; and a patterned
dielectric layer, covering the surface of the conductive layer,
wherein the tips of the conductive cylinders are exposed on a
surface of the dielectric layer far away from the conductive layer,
and the height of the conductive cylinders is relatively lower than
the dielectric layer and the conductive cylinders sunk into the
dielectric layer.
15. The circuit board structure with concave conductive cylinders
of claim 14, further comprises a solder material layer formed on
the conductive cylinders to rise above the dielectric layer.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 96127050, filed on Jul. 25, 2007. All
disclosure of the Taiwan application is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a circuit board structure
and the fabricating method thereof, more specifically, the present
invention relates to a circuit board structure with concave
conductive cylinders and the fabricating method thereof.
[0004] 2. Description of Related Art
[0005] Generally, conventional circuit boards used to carry and
electrically connect a plurality of electronic elements are mainly
formed with a plurality of interlayered patterned conductive layers
and dielectric layers. The patterned conductive layers are defined
and formed through patterning copper foil directly, or through
copper electroplating upon copper foil to increase the thickness of
conductive layer and then go through a patterning process. The
dielectric layers are respectively disposed between these adjacent
patterned conductive layers to insulate these patterned conductive
layers. In addition, the interlayered patterned conductive layers
are electrically connected to each other through conductive vias.
In addition, various electronic elements (e.g. active elements or
passive elements) may be further disposed on a surface of the
circuit board, and through the internal circuit in the circuit
board to realize electrical signal propagation.
[0006] FIG. 1 is a section view of a circuit board of prior arts.
With reference to FIG. 1, a patterned conductive layer 120 of a
circuit board 100 of prior arts is disposed on a dielectric layer
110, and the patterned conductive layer 120 has a plurality of pads
122. A patterned solder mask layer 130 is disposed on the
dielectric layer 110 to cover a portion of the patterned conductive
layer 120. The patterned solder mask layer 130 has a plurality of
openings 132 to expose these pads 122. In addition, a plurality of
solder balls 140 are respectively disposed on these pads 122 and
are respectively electrically connected to these pads 122.
[0007] However, during the fabricating process of the circuit board
100 of prior arts, when the patterned solder mask layer 130 is
formed, the locations of the openings 132 may not be accurately
aligned to the pads 122, and drifts may occur accordingly. And
therefore a portion of the pads 122 (with reference to the pads 122
on the right side of FIG. 1) are covered too much by the patterned
solder mask layer 130. In addition, when an image transfers, light
leaking, under exposure, less developing power or incomplete
development may also lead to too small openings 132. Therefore,
when the solder balls 140 are respectively formed on the pads 122,
the contact area between a portion of the solder balls 140 (with
reference to the solder balls on the right side of FIG. 1) and the
corresponding pads 122 become small, therefore the bonding
reliability between a portion of the solder balls 140 and the
corresponding pads 122 is reduced.
SUMMARY OF THE INVENTION
[0008] The present invention provides a circuit board structure
with concave conductive cylinders and the fabricating method
thereof, for fabricating circuit board structure with concave
conductive cylinders, so that the bonding quality between solder
material and conductive cylinder is better.
[0009] The present invention provides a fabricating method of
circuit board structure with concaved conductive cylinders. The
method includes: providing a conductive layer first; forming a
plurality of conductive cylinders on a surface of the conductive
layer; forming a dielectric layer on the surface of the conductive
layer on which the conductive cylinders are formed; exposing the
tips of these conductive cylinders out of a surface of the
dielectric layer relatively far away from the conductive layer;
removing the tips of the conductive cylinders, so that the height
of the conductive cylinders is lower than the height of the
dielectric layer and the conductive cylinders sunk into the
dielectric layer.
[0010] In an embodiment of the present invention, the step of
forming the conductive cylinders includes partially etching the
conductive layers.
[0011] In an embodiment of the present invention, the step of
forming the dielectric layer includes laminating or printing a
dielectric material on the surface of the conductive layer on which
the conductive cylinders are formed.
[0012] In an embodiment of the present invention, the method of
removing the exposed tips of the conductive cylinders includes
etching.
[0013] In an embodiment of the present invention, after the exposed
tips of these conductive cylinders are removed, the present method
further includes disposing a solder material on the conductive
cylinders sunk into the dielectric layer, so as to rise the solder
material above the dielectric layer.
[0014] The present invention further provides a method of
fabricating the circuit board with concave conductive cylinders.
The method includes: providing a conductive layer first; forming a
dielectric layer on a surface of the conductive layer; forming a
plurality of vias in the dielectric layer, wherein the vias are
exposed on the surface of the conductive layer; filling a
conductive material in the vias to form a plurality of conductive
cylinders on the surface of the conductive layer, so that the tips
of the the conductive cylinders are exposed on a surface of the
dielectric layer relatively far away from the conductive layer; and
removing the exposed tips of the conductive cylinders, so that the
height of the conductive cylinders is lower than the dielectric
layer and the conductive cylinders sunk into the dielectric
layer.
[0015] In an embodiment of the present invention, the step of
forming the dielectric layer includes laminating or printing a
dielectric material on the surface of the conductive layer.
[0016] In an embodiment of the present invention, the method of
forming the vias includes laser drilling.
[0017] In an embodiment of the present invention, the method of
filling the conductive material in the vias includes
electroplating, screen printing conductive glue or conductive
polymeric material.
[0018] In an embodiment of the present invention, the conductive
glue includes copper paste or silver paste.
[0019] In an embodiment of the present invention, the method of
removing the exposed tips of the conductive cylinders includes
grinding or etching.
[0020] In an embodiment of the present invention, after the exposed
tips of the conductive cylinders are removed, the present method
further includes disposing a solder material on the conductive
cylinders sunk into the dielectric layer to rise the solder
material above the dielectric layer.
[0021] The present invention further provides a circuit board
structure with concave conductive cylinders, including a conductive
layer, a plurality of conductive cylinders and a patterned
dielectric layer. The conductive cylinders are formed on a surface
of the conductive layer and are electrically connected to the
conductive layer. The patterned dielectric layer covers a surface
of the conductive layer, wherein the tips of the conductive
cylinders are exposed on a surface of the patterned dielectric
layer far away from the conductive layer, and the height of these
conductive cylinders is lower than the patterned dielectric layer
and the conductive cylinders sunk into the patterned dielectric
layer.
[0022] In an embodiment of the present invention, the circuit board
structure further includes a solder material layer, formed on the
conductive cylinders to rise above the patterned dielectric
layer.
[0023] Since the present invention forms the dielectric layer on
the outside of the conductive layer, to substitute the function of
solder mask layer, therefore the solder mask opening drift problem
occurred in the prior arts because the solder mask layer has to
align with the pads, or the problem that the solder mask openings
are too small when image transfers can be avoided. In addition,
since the conductive cylinders are sunk into the dielectric layer,
so that the solder material can be filled in the dielectric layer
and to effectively bond to the conductive cylinders, therefore the
bonding reliability of the solder material and the conductive
cylinders can be improved, and disposing pads is no more
required.
[0024] In order to the make the aforementioned and other objects,
features and advantages of the present invention comprehensible, a
preferred embodiment accompanied with figures is described in
detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a section view of a circuit board of prior
arts.
[0026] FIG. 2A.about.FIG. 2F are diagrams of the flow of
fabricating the circuit board structure with concave conductive
cylinders of the first embodiment of the present invention.
[0027] FIG. 3A.about.FIG. 3F are diagrams of the flow of
fabricating the circuit board structure with concave conductive
cylinders of the second embodiment of the present invention.
DESCRIPTION OF THE EMBODIMENTS
First Embodiment
[0028] FIG. 2A.about.FIG. 2F are flow diagrams of fabricating the
circuit board structure with concave conductive cylinders of the
first embodiment of the present invention. With reference to FIG.
2A, first a conductive layer 210 is provided, the conductive layer
210 for example is a metal layer, the material of the conductive
layer 210 may be copper. Next, with reference to FIG. 2B, partially
etching the conductive layer 210 is conducted, so that a plurality
of conductive cylinders 220 are formed on the surface 212 of the
conductive layer. In another embodiment which is not shown, the
conductive cylinders 220 may also be formed on the surface 212 of
the conductive layer 210 through forming bumps using welding wire
machine or through other appropriate method.
[0029] Next, with reference to FIG. 2C, a dielectric layer 230 is
formed on the surface 212 of the conductive layer 210 on which the
conductive cylinders 220 are formed. The method of forming the
dielectric layer 230 on the conductive layer 210 includes
laminating a dielectric material and the conductive layer 210
together, or forming the dielectric layer 230 on the conductive
layer 210 through the method of printing dielectric material. Next,
with reference to FIG. 2D, the tips 222 of the conductive cylinders
220 on a surface 232 of the dielectric layer 230 far away from the
conductive layer 210 are exposed. For example, before the
dielectric material is cured, laminate the conductive layer 210 to
the dielectric material directly, until the tips 222 of these
conductive cylinders 220 are exposed out of the dielectric
material. Or, after the dielectric material is cured, a grinding
process is employed until the tips 222 of the conductive cylinders
220 are exposed out of the cured dielectric material.
[0030] Next, with reference to FIG. 2E, the tips 222 of the
conductive cylinders 220 may be removed through etching method or
the like, so that the height h1 of the conductive cylinders 220 is
lower than the height h2 of the dielectric layer 230. In addition,
in the present embodiment, during the process of etching the
conductive cylinders 220, the conductive layer 210 may be partially
etched in the same time, so as to form the patterned conductive
layer 210a, and the fabricating steps are therefore reduced. Next,
with reference to FIG. 2F, in the present embodiment, after the
tips 222 of the conductive cylinders 220 are removed, a solder
material is disposed on the conductive cylinders 220 sunk into the
dielectric layer 230 through electroplating or printing method, so
that a solder material layer 240 is formed.
[0031] In other words, after the previous fabricating method is
performed, a circuit board structure 200 with concave conductive
cylinders can be fabricated. Moreover, the circuit board structure
200 with concave conductive cylinders further includes a conductive
layer 210 (patterned conductive layer 210a), a plurality of
conductive cylinders 220 and a patterned dielectric layer 230.
[0032] As shown in FIG. 2E, the conductive cylinders 220 are formed
on a surface 212 of the conductive layer 210, and electrically
connected to the conductive layer 210. The patterned dielectric
layer 230 covers the surface 212, wherein the tips 222 of the
conductive cylinders 220 are exposed on a surface 232 of the
patterned dielectric layer 230 far away from the conductive layer
210, and the height of the conductive cylinders 220 is relatively
lower than the patterned dielectric layer 230 to sink into the
patterned dielectric layer 230. In addition, in FIG. 2F, the
circuit board structure 200 with concave conductive cylinders
further includes a solder material layer 240 formed on the
conductive cylinders 220 to rise above the patterned dielectric
layer 230. In addition, the material of the conductive layer 210 is
the same as the conductive cylinders 220; the material thereof
includes copper, aluminum or the alloy thereof.
[0033] It has to be addressed herein, the circuit board structure
200 with concave conductive cylinders may be applied in chip
package structure of different forms, and the appearance thereof
may vary with the requirements of designers. In addition, the
circuit board structure 200 with concave conductive cylinders may
further includes a plurality of conductive layers 220 and a
plurality of patterned dielectric layers 230 which are disposed
interlayering with each other. Therefore the present embodiment is
only exemplary, and is not to limit the present invention. In
addition, the circuit board structure 200 with concave conductive
cylinders is not limited to the fabricating method of the present
embodiment to fabricate.
Second Embodiment
[0034] FIG. 3A.about.FIG. 3F are diagrams of the flow of
fabricating the circuit board structure with concave conductive
cylinders of the second embodiment of the present invention. The
present embodiment is similar to the previous embodiment, the only
difference is that: in the previous embodiment, the dielectric
layer 230 is formed after the conductive cylinders 220 are formed;
while in the present embodiment, the dielectric layer 320 is formed
before the conductive cylinders 330 are formed. Refer the following
descriptions for the flow detail, the similarities thereof will not
be repeated.
[0035] With reference to FIG. 3A, a conductive layer 310 which has
a surface 312 is formed. Next, with reference to FIG. 3B, by using
laminating method or printing method or the alike, a dielectric
layer 320 is formed on the surface 312 of the conductive layer 310
on which the conductive cylinders 330 are formed. Further next,
with reference to FIG. 3C, a plurality of vias 322 are formed in
the dielectric layer 320 by using laser drilling or lithography
method, so as to expose a portion of the surface 312 of the
conductive layer 310.
[0036] Next, with reference to FIG. 3D, through for example
printing and filling, electroplating, sputtering or vapour
deposition method to fill a conductive material into the vias 322,
so as to form a plurality of conductive cylinders 330 on the
surface of the conductive layer 310, wherein the tips of the
conductive cylinders 330 are respectively exposed from the vias
322. In the present embodiment, the conductive material includes
copper, copper paste, silver paste or conductive polymeric
material. Further next, with reference to FIG. 3E, for example
etching method is used to remove the exposed tips 332 of the
conductive cylinders 330, so that the height h3 of the conductive
cylinders 330 is relatively lower than the height h4 of the
dielectric layer 320. When the tips 332 of the conductive cylinders
330 are etched, the patterned conductive layer 300 may also be
formed simultaneously. Further next, with reference to FIG. 3F, a
solder material layer 340 is formed on the surface of the
conductive cylinders 330.
[0037] By the way, in another embodiment, when filling conductive
material into the vias 322 through electroplating method, the
surface 324 (as shown in FIG. 3D) of the dielectric layer 320 may
also be plated a layer of metal. Next, expose the surface 324 of
the dielectric layer 320 through grinding or etching method. In
addition, in another embodiment, when filling conductive material
into the vias 322, the height h3 (as shown in FIG. 3E) of the
formed conductive cylinders 330 is controlled through disposing a
plating mask layer at the openings 322a (as shown in FIG. 3C) of
the vias 322, so that the height h3 of these conductive cylinders
330 is relatively lower than the height h4 (as shown in FIG. 3E) of
the dielectric layer. Thus, the step for removing the tips 332 of
the conductive cylinders 330 may be omitted.
[0038] Through the previous fabrication, the circuit board
structure 300 (with reference to FIG. 3F) with concave conductive
cylinders may be fabricated. The structure thereof is similar to
the circuit board structure 200 (with reference to FIG. 2F) with
concave conductive cylinders of the previous embodiment. Briefly,
the circuit board structure 300 with concave conductive cylinders
includes a conductive layer 310 (patterned conductive layer 310a),
a plurality of conductive cylinders 330 and a patterned dielectric
layer 320, wherein these conductive cylinders 330 are sunk into the
patterned dielectric layer 320. In addition, in FIG. 3F, the
circuit board structure 300 with concave conductive cylinders may
further include a solder material layer 340.
[0039] To sum up, since the present invention forms the dielectric
layer on the outside of the conductive layer, therefore the solder
mask layer may be substituted to ensure that the conductive layer
does not contact the solder material. Therefore, the problem in the
prior arts, that the solder mask layer has to be aligned to the
pads which results in solder mask opening drift, or the problem
that the solder mask openings are too small when image transfers
can be avoided. In addition, since the conductive cylinders are
sunk into the dielectric layer, so that solder material can be
filled in the dielectric layer, thus the structural intensity is
better, so that the solder material effectively contacts with the
conductive cylinders. Therefore the bonding reliability between the
solder material and the conductive cylinders is improved, and no
pads need to be disposed additionally.
[0040] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
present invention cover modifications and variations of this
invention provided they fall within the scope of the following
claims and their equivalents.
* * * * *