U.S. patent application number 13/186486 was filed with the patent office on 2011-11-10 for inner substrate for manufacturing multilayer printed circuit boards.
This patent application is currently assigned to FOXCONN ADVANCED TECHNOLOGY INC.. Invention is credited to CHENG-HSIEN LIN, CHIH-KANG YANG.
Application Number | 20110274866 13/186486 |
Document ID | / |
Family ID | 40247904 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110274866 |
Kind Code |
A1 |
YANG; CHIH-KANG ; et
al. |
November 10, 2011 |
INNER SUBSTRATE FOR MANUFACTURING MULTILAYER PRINTED CIRCUIT
BOARDS
Abstract
An exemplary inner substrate for manufacturing multilayer
printed circuit boards is provided. The inner substrate has a
number of substrate units and a number of transverse folding
portions alternately arranged along a longitudinal direction of the
inner substrate. Each of the substrate units is configured for
forming a unitary printed circuit board. Each of the folding
portions is interconnected between neighboring substrate units.
Each of the folding portions defines at least one line of weakness
perpendicular to the longitudinal direction of the inner substrate
for facilitating folding and unfolding the neighboring substrate
units to each other. Each of the folding portions defines at least
one groove in at least one side thereof along the at least one line
of weakness.
Inventors: |
YANG; CHIH-KANG; (Taoyuan,
TW) ; LIN; CHENG-HSIEN; (Taoyuan, TW) |
Assignee: |
FOXCONN ADVANCED TECHNOLOGY
INC.
Tayuan
TW
|
Family ID: |
40247904 |
Appl. No.: |
13/186486 |
Filed: |
July 20, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12702439 |
Feb 9, 2010 |
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13186486 |
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11959212 |
Dec 18, 2007 |
7698811 |
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12702439 |
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Current U.S.
Class: |
428/43 |
Current CPC
Class: |
H05K 3/4611 20130101;
H05K 2201/055 20130101; H05K 2201/1028 20130101; H05K 2201/09036
20130101; H05K 3/4652 20130101; Y10T 428/15 20150115; H05K 3/0097
20130101; Y10T 29/49165 20150115; Y10T 29/49124 20150115; H05K
3/242 20130101; H05K 1/0393 20130101; H05K 3/4691 20130101; H05K
2201/09063 20130101; H05K 2203/1536 20130101; H05K 3/4635 20130101;
Y10T 29/49135 20150115; Y10T 29/49126 20150115; Y10T 29/4913
20150115; H05K 3/06 20130101; H05K 2203/1545 20130101 |
Class at
Publication: |
428/43 |
International
Class: |
B65D 65/28 20060101
B65D065/28 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 13, 2007 |
CN |
200710076017.5 |
Aug 3, 2007 |
TW |
96128530 |
Claims
1. An inner substrate for manufacturing multilayer printed circuit
boards, the inner substrate comprising: a plurality of substrate
units and a plurality of transverse folding portions alternately
arranged along a longitudinal direction of the inner substrate,
each of the substrate units being configured for forming a unitary
multilayer printed circuit board, each of the folding portions
being interconnected between two neighboring substrate units, each
of the folding portions defining at least one line of weakness
perpendicular to the longitudinal direction of the inner substrate
for facilitating folding and unfolding the inner substrate, wherein
each of the folding portions defines at least one groove in at
least one side thereof along the at least one line of weakness; and
at least a conductive adhesive tape attached to the inner substrate
to electrically connect the conductive layers of two neighboring
substrate units.
2. The inner substrate of claim 1, wherein the inner substrate
includes an insulating base film and two electrically conductive
layers formed on two opposite sides of the insulating base film,
and a thickness of the at least one groove is larger than a
thickness of one of the electrically conductive layers and less
than a sum of thicknesses of the insulating base film and one of
the electrically conductive layers.
3. The inner substrate of claim 1, wherein each of the folding
portions defines at least one groove in each of the two opposite
sides of the inner substrate along the at least one line of
weakness.
4. The inner substrate of claim 1, wherein the at least one line of
weakness includes a first line and a second line parallel to the
first line, each of the folding portions comprising a first groove
in at least one side thereof along the first line and a second
groove in the at least one side thereof along the second line.
5. The inner substrate of claim 3, wherein the distances between
the first line and the second line of the folding portions are
equal to each other.
6. The inner substrate of claim 3, wherein the distances between
the first line and the second line of the folding portions are
different from each other.
7. The inner substrate of claim 1, wherein the at least one line of
weakness includes a first line and a second line parallel to the
first line, each of the folding portions comprising a first groove
defined in each of opposite sides of the inner substrate along the
first line and a second groove defined in each of the opposite
sides of the inner substrate along the second line.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of and claims
the benefit of U.S. patent application Ser. No. 12/702,439 filed
Feb. 9, 2010, entitled "INNER SUBSTRATE FOR MANUFACTURING
MULTILAYER PRINTED CIRCUIT BOARDS", which is also a divisional
application of and claims the benefit of U.S. patent application
Ser. No. 11/959,212 filed Dec. 18, 2007, entitled "METHOD FOR
MANUFACTURING MULTILAYER PRINTED CIRCUIT BOARDS USING INNER
SUBSTRATE", the entire contents of which are incorporated herein by
reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure relates to printed circuit boards,
and more particularly relates to an inner substrate for
manufacturing multilayer printed circuit boards and a method for
manufacturing multilayer printed circuit boards using the inner
substrate.
[0004] 2. Description of Related Art
[0005] In order to accommodate development of miniaturization and
multifunction of electronic products, multilayer printed circuit
boards are widely used due to their characteristics such as
micromation, light quality, high-density interconnection.
[0006] Multilayer printed circuit boards usually include multilayer
rigid printed circuit boards and multilayer flexible printed
circuit boards. Nowadays, multilayer printed circuit boards are
manufactured using a typical sheet-by-sheet process. However, only
one multilayer printed circuit board can be manufactured at a time,
using the typical method describe above. Thus, efficiency of
manufacturing multilayer printed circuit boards is low and cost of
manufacturing multilayer printed circuit boards is high.
[0007] Currently, flexible printed boards can be manufactured using
a roll-to-roll process that is a substitute of a typical
sheet-by-sheet process. The roll-to-roll process can enhance
efficiency of manufacturing flexible printed boards. However, a
multilayer flexible printed circuit board is generally thicker than
a single layer flexible printed circuit board, flexibility of the
multilayer flexible printed circuit board is low. Thus, it is
difficult for the multilayer flexible printed circuit board to be
wrapped around a roller. Therefore, the roll-to-roll process for
manufacturing the single flexible printed circuit board is not
suitable for manufacturing the multilayer flexible printed circuit
board. Therefore, multilayer flexible printed circuit boards are
still manufactured using the sheet-by-sheet process like typical
multilayer rigid printed circuit boards. Thus, efficiency of
manufacturing multilayer flexible printed circuit boards is also
low and cost of manufacturing multilayer flexible printed circuit
boards is also high.
[0008] What is needed, therefore, is an inner substrate for
manufacturing multilayer printed circuit boards and a method for
manufacturing multilayer printed circuit boards using the inner
substrate, thereby improving efficiency of manufacturing multilayer
printed circuit boards.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Many aspects of the present embodiments can be better
understood with reference to the following drawings. The components
in the drawings are not necessarily drawn to scale, the emphasis
instead being placed upon clearly illustrating the principles of
the present embodiments. Moreover, in the drawings, like reference
numerals designate corresponding parts throughout the several
views.
[0010] FIG. 1 is a schematic view of an inner substrate according
to a present embodiment.
[0011] FIG. 2 is a schematic, cross-sectional view of the inner
substrate in FIG. 1.
[0012] FIG. 3 is a schematic view of another inner substrate
according to the present embodiment.
[0013] FIG. 4 is a schematic, cross-sectional view of the inner
substrate in FIG. 3.
[0014] FIG. 5 is a schematic view of further another inner
substrate according to the present embodiment.
[0015] FIG. 6 is a schematic, cross-sectional view of the inner
substrate in FIG. 5.
[0016] FIG. 7 is a schematic, cross-sectional view of an inner
substrate having circuit substrates laminated thereon according to
the present embodiment.
[0017] FIG. 8 is a schematic, cross-sectional view of folding of
the substrate units of an inner substrate having circuit substrates
laminated thereon according to the present embodiment.
[0018] FIG. 9 is a schematic, cross-sectional view of unfolding and
folding of the substrate units of an inner substrate having circuit
substrates laminated thereon according to the present
embodiment.
[0019] FIG. 10 is a schematic view of an inner substrate having
conductive adhesive tapes attaching thereon.
DETAILED DESCRIPTION
[0020] Embodiments will now be described in detail below and with
reference to the drawings.
[0021] Referring to FIG. 1 and FIG. 2, an exemplary inner substrate
10 for manufacturing multilayer printed circuit boards is shown.
The inner substrate 10 is elongated tape-shaped. The inner
substrate 10 can be a rigid printed circuit substrate or a flexible
printed circuit substrate. The inner substrate 10 can be a
single-layer structure or a multilayer structure containing two
layers, four layers, six layers or more. In the present embodiment,
referring to FIG. 2, the inner substrate 10 is a double-sided
structure. The inner substrate 10 includes an insulating base film
and two electrically conductive layers formed on two opposite sides
of the insulating base film. The inner substrate 10 has a number of
substrate units 11 and a number of transverse folding portions 20
alternately arranged along a longitudinal direction thereof.
[0022] In detail, the substrate units 11 are arranged along a
longitudinal direction of the inner substrate 10. Each of the
substrate units 11 includes an insulating layer 12 (i.e., the
insulating base film of the inner substrate 10) and two conductive
circuit layers 13 (i.e., the corresponding electrically conductive
layer of the inner substrate 10). The conductive circuit layers 13
are configured for forming conductive circuit patterns on two
opposite sides of the insulating layer 12, respectively. Each of
the substrate units 11 can be configured for forming a unitary
printed circuit board. Each of the folding portions 20
interconnects the two neighboring substrate units 11. Thus, the
folding portions 20 are also arranged along a longitudinal
direction of the inner substrate 10. Therefore, it is noted that
the inner substrate 10 is divided into a number of the substrate
units 11 by the folding portions 20.
[0023] Each of the folding portions 20 defines two line of
weaknesses including a first line 211 and a second line 212 both
perpendicular to the longitudinal direction of the inner substrate
10, for facilitating folding and unfolding the neighboring
substrate units 11 with/from each other. The first line 211 is
parallel to the second line 212. Each of the folding portions 20
defines a number of first through-holes 21 aligned in the first
line 211 and a number of second through-holes 22 aligned in the
second line 212. A distance between the first line 211 and the
second line 212 is determined by a thickness of the corresponding
multilayer printed circuit board finally produced. Generally, the
distance between the first line 211 and the second line 212 is
either equal to or larger than a total thickness of two neighboring
stacked substrate units 11 of the inner substrate 10 and two
circuit substrates sandwiched between the stacked substrate units
11 once the inner substrate 10 has been folded. That is, at least
one circuit substrate is laminated onto each of the two neighboring
substrate units 11, on an identical side of the inner substrate 10,
and then later on the two adjacent circuit substrates on the
identical side of the inner substrate 10 become sandwiched between
the two neighboring substrate units 11 during folding of the inner
substrate 10. For more details, please refer to the description
provided below in relation to FIG. 7.
[0024] Additionally, in general, the thicknesses of the two circuit
substrates sandwiched between any two neighboring stacked substrate
units 11 may be the same or may be different. Accordingly, the
distance between the first line 211 and the second line 212 of each
folding portion 20 can be identical with that of the other folding
portions 20 or different from that of any or all of the other
folding portions 20. Because the weakness of the inner substrate 10
at the first through-holes 21 and the second through-holes 22, the
flexibility of inner substrate 10 is increased,
especially/particularly at the area of the first through-holes 21
and the second through-holes 22. Thus, the inner substrate 10 can
be folded or unfolded at the first through-holes 21 along the first
line 211 and the second through-holes 22 along the second line
212.
[0025] It is noted that the folding portions 20 can be in other
structures.
[0026] Referring to FIGS. 3 and 4, another exemplary inner
substrate 30 for manufacturing multilayer printed circuit boards is
shown. The inner substrate 30 is similar to the inner substrate 10
except for folding portions 35. Each of the folding portions 35
defines a line of weakness including a third line 350 for
facilitating folding and unfolding the neighboring substrate units
31 with/from each other. The third line 350 extends perpendicularly
to a longitudinal direction of the inner substrate 30. Each of the
folding portions 35 defines a groove 351 on one side thereof along
the third line 350. A width of the groove 351 is determined by a
thickness of the corresponding multilayer printed circuit board
finally produced. Generally, the width of the groove 351 is either
equal to or larger than a total thickness of e two neighboring
stacked substrate units 31 of the inner substrate 30 and two
circuit substrates sandwiched between the stacked substrate units
31 once the inner substrate 30 has been folded. That is, at least
one circuit substrate is laminated onto each of the two neighboring
substrate units 31, on an identical side of the inner substrate 30,
and then later on the two adjacent circuit substrates on the
identical side of the inner substrate 30 become sandwiched between
the neighboring substrate units 31 during folding of the inner
substrate 30. It is noted that each of the folding portions 35 can
define a groove 351 at each of the two opposite sides of the inner
substrate 30.
[0027] Referring to FIGS. 5 and 6, further another exemplary inner
substrate 40 for manufacturing multilayer printed circuit boards is
shown. The inner substrate 40 is similar to the inner substrate 10
except the folding portions 45. Each of the folding portions 45
defines a first groove 451 along a first line 450 and a second
groove 453 along a second line 452. It is noted that each of the
folding portions 45 can define a first groove 451 along the first
line 450 respectively on two opposite sides of the inner substrate
40 and a second groove 453 along the second line 452 respectively
on two opposite sides of the inner substrate 40.
[0028] Multilayer printed circuit boards can be manufactured using
the inner substrate 10, 30, or 40, as described above. In the
present embodiment, the method for manufacturing multilayer printed
circuit boards using the inner substrate 10 includes the following
steps.
[0029] Step 1: the inner substrate 10, as described above, is
formed.
[0030] In the present embodiment, the inner substrate 10 is a
single-layer double-sided structure, therefore, the inner substrate
10 can be formed with a double-sided copper-clad substrate. A large
sheet of raw double-sided copper-clad substrate is divided into a
number of elongated tape-shaped double-sided copper-clad substrate
according to sizes of multilayer printed circuit boards. The
elongated tape-shaped double-sided copper-clad substrate can be
wrapped around a roller and be configured for forming the inner
substrate 10. The conductive circuit layer 13 on the two opposite
sides of the inner substrate 10 can be formed with two copper foils
of the double-sided copper-clad substrate using a photolithographic
process or a laser ablation process.
[0031] The folding portions 20 can be formed before or after the
conductive circuit layers 13 are formed. The folding portions 20
can be formed using a laser drilling process, a mechanical drilling
process or a chemical etching process.
[0032] Step 2: at least one circuit substrate is laminated on each
of the substrate units 11 of the inner substrate 10.
[0033] For the purpose of illustration only, in the present
embodiment, each of the substrate units 11 of the inner substrate
10 has two circuit substrates laminated on two opposite sides
thereof, respectively. It is noted that in alternative embodiments,
each of the substrate units 11 of the inner substrate 10 can have
only one circuit substrate laminated on only one side thereof. The
circuit substrates laminated can be rigid printed circuit
substrates or flexible printed circuit substrates. The circuit
substrates can be single-layer structures, or multilayer structures
containing two layers, four layers, six layers or more. In the
present embodiment, each of the circuit substrates is a
single-sided structure that including an insulating layer and an
electrically conductive layer. During laminating the circuit
substrates, the insulating layer of each of the circuit substrates
is in contact with the corresponding conductive circuit layer 13 of
the corresponding substrate unit 11. Thereby, the circuit
substrates are laminated onto the two opposite sides of the
substrate unit 11.
[0034] In detail, referring to FIG. 7, the inner substrate 10 can
be provided using a roller 15. The inner substrate 10 includes a
first substrate unit 111, a second substrate unit 112, a third
substrate unit 113, a first folding portion 201 and a second
folding portion 202. The first folding portion 201 interconnects
the first substrate unit 111 and the second substrate unit 112. The
second folding portion 202 interconnects the second substrate unit
112 and the third substrate unit 113. During laminating, a first
circuit substrate 301 and a second circuit substrate 401 are
laminated onto two opposite sides of the first substrate unit 111,
respectively. A third circuit substrate 302 and a fourth circuit
substrate 402 are laminated onto two opposite sides of the second
substrate unit 112, respectively. A fifth circuit substrate 303 and
a sixth circuit substrate 403 are laminated onto two opposite sides
of the third substrate unit 113, respectively.
[0035] In the present embodiment, the first circuit substrate 301,
the second circuit substrate 401, the third circuit substrate 302,
the fourth circuit substrate 402, the fifth circuit substrate 303
and the sixth circuit substrate 403 have an identical thickness. It
is noted that the first circuit substrate 301, the second circuit
substrate 401, the third circuit substrate 302, the fourth circuit
substrate 402, the fifth circuit substrate 303 and the sixth
circuit substrate 403 can have different thicknesses. Each of the
first circuit substrate 301, the second circuit substrate 401, the
third circuit substrate 302, the fourth circuit substrate 402, the
fifth circuit substrate 303 and the sixth circuit substrate 403 has
at least one electrically conductive layer. It is noted that a
circuit pattern can be preformed in the at least one electrically
conductive layer. Alternatively, the circuit pattern could be
formed in a later step, e.g. after the step of unfolding the inner
substrate, which should also be considered to have the same
meanings of "circuit substrates" of the present invention.
[0036] Step 3: the inner substrate 10 is folded in a manner such
that at least two of the substrate units 11 are stacked one on
another.
[0037] In detail, in order to stack the second substrate unit 112
on the first substrate unit 111, a distance between the first line
of the first through-holes 2011 and the second line of the second
through-holes 2012 of the first folding portion 201 is equal to a
total thickness of the inner substrate 10, the first circuit
substrate 301 laminated onto the first substrate unit 111 and the
third circuit substrate 302 laminated onto the second substrate
unit 112. Referring FIG. 8, after laminating, the inner substrate
10 can be folded at the first folding portion 201, and thus the
second substrate unit 112 is stacked on the first substrate unit
111. In such configuration, the third circuit substrate 302
laminated onto the second substrate unit 112 can contact with and
disposed onto the first circuit substrate 301 laminated onto the
first substrate unit 111. Thus, the first circuit substrate 301 and
the third circuit substrate 302 are sandwiched between the first
substrate unit 111 and the second substrate unit 112.
[0038] Similarly, in order to stack the third substrate unit 113 on
the second substrate unit 112, a distance between the first line of
the first through-holes 2021 and the second line of the second
through-holes 2022 of the second folding portion 202 is equal to a
total thickness of the inner substrate 10, the fourth circuit
substrate 401 laminated onto the second substrate unit 112 and the
sixth circuit substrate 403 laminated onto the third substrate unit
113. The inner substrate 10 can also be folded at the second
folding portion 202, and thus the third substrate unit 113 is
stacked on the second substrate unit 112. In such configuration,
the sixth circuit substrate 403 laminated onto the third substrate
unit 113 can be in contact with and disposed onto the fourth
circuit substrate 402 laminated onto the second substrate unit 112.
The fourth circuit substrate 401 and the sixth circuit substrate
403 are sandwiched between the second substrate unit 112 and the
third substrate unit 113. Similarly, multiple substrate units 11
laminated with circuit substrates can be stacked one by one in the
manner described above.
[0039] Additionally, because the circuit substrates are laminated
onto the substrate units 11 using an adhesive, the surplus adhesive
may overflow from the edges of the substrate units 11 and the
circuit substrates during laminating. When the substrate units 11
are stacked one by one, the surplus adhesive may overflow and cause
the substrate units 11 to adhere to each other. Thus, it is
difficult for the substrate units 11 to be stacked or unstacked
repeatedly. Advantageously, when one substrate unit 11 is stacked
on another substrate unit 11, a separating film (not shown) can be
interposed between the two neighboring stacked substrate units 11.
For example, in the present embodiment, one separating film can be
interposed between the third circuit substrate 302 laminated onto
the second substrate unit 112 and the first circuit substrate 301
laminated onto the first substrate unit 111, and another separating
film can be interposed between the sixth circuit substrate 403
laminated onto the third substrate unit 113 and the fourth circuit
substrate 402 laminated onto the second substrate unit 112.
[0040] Step 4: the stacked substrate units 11 are unfolded.
[0041] Generally, a process for manufacturing multilayer printed
circuit boards using the substrate units of the inner substrate 10
includes the step of drilling holes in the circuit substrates,
forming electrical traces on the circuit substrates, electroplating
gold on terminals of the electrical traces, laminating protective
films on the circuit substrates, inspecting electrical connection
and external appearance, and so on. Therefore, the stacked
substrate units may need to be unfolded to undergo these steps.
[0042] It is understood that the inner substrate 10 stacked as
described above can be unfolded at the first folding portion 201
and the second folding portion 202. Thus the third substrate unit
113 can be unstacked from the second substrate unit 112, and the
second substrate unit 112 can unstacked from the first substrate
unit 111. Similarly, multiple substrate units 11 can be unstacked
one by one. When one substrate unit 11 is unstacked from the other
substrate units 11, sequential steps to form multilayer printed
circuit boards, for example, forming outside electrical traces on
the circuit substrates, electroplating gold on terminals of the
electrical traces, and laminating protective films on the circuit
substrates, can be performed.
[0043] Step 5: the at least one circuit substrate on each of the
unfolded substrate units 11 is processed.
[0044] The sequential steps includes drilling holes in the circuit
substrates, forming outside electrical traces on the circuit
substrates, electroplating gold on terminals of the electrical
traces, laminating protective films on the circuit substrates,
inspecting electrical connection and external appearance, and so
on. In these steps, referring to FIG. 9, multilayer printed circuit
boards can be manufactured using the substrate units 11 of the
inner substrate 10 in a manner such that the inner substrate 10 is
unfolded at the folding portions 20. When one substrate unit 11 is
unfolded from a stack of the substrate units 11, one of the steps
of drilling holes in the circuit substrates, forming outside
electrical traces on the circuit substrates, electroplating gold,
laminating protective films on the circuit substrates, and
inspecting electrical connection and external appearance, can be
performed on the one unfolded substrate unit 11.
[0045] It is understood that, after one substrate unit 11 has
undergone one of the steps of drilling holes in the circuit
substrates, forming electrical traces on the circuit substrates,
electroplating gold on terminals of the electrical traces,
laminating protective films on the circuit substrates, and
inspecting electrical connection and external appearance, the one
unfolded substrate unit 11 can be stacked on the other substrate
units 11 again. For example, as shown in FIG. 9, the one unfolded
substrate unit 11 can be stacked on the other substrate units 11
that have already undergone the same step. It is also understood
that some steps can be performed on the stacked substrate units 11.
For example, a baking step can be performed after the substrate
units 11 laminated with the circuit substrates are stacked
together.
[0046] Preferably, in the step of electroplating gold on terminals
of the electrical traces, at least a conductive adhesive tape 50
can be attached on the inner substrate 10, as shown in FIG. 10. The
conductive adhesive tape 50 is configured for connecting the two
neighboring substrate units 11 so as to electrically connect the
conductive circuit patterns formed with conductive circuit layers
13 of the two neighboring substrate units 11. The conductive
adhesive tape 50 can be attached onto the conductive circuit layers
13 using a method such as a thermal attachment or an ultrasonic
attachment.
[0047] While certain embodiments have been described and
exemplified above, various other embodiments will be apparent to
those skilled in the art from the foregoing disclosure. The present
disclosure is not limited to the particular embodiments described
and exemplified but is capable of considerable variation and
modification without departure from the scope of the appended
claims.
* * * * *