U.S. patent application number 13/474388 was filed with the patent office on 2012-09-06 for method of manufacturing a printed circuit board.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Jee Soo MOK, Chang Sup Ryu, Je Gwang Yoo.
Application Number | 20120222299 13/474388 |
Document ID | / |
Family ID | 42318241 |
Filed Date | 2012-09-06 |
United States Patent
Application |
20120222299 |
Kind Code |
A1 |
MOK; Jee Soo ; et
al. |
September 6, 2012 |
METHOD OF MANUFACTURING A PRINTED CIRCUIT BOARD
Abstract
A printed circuit board and a method of manufacturing the
printed circuit board, in which the printed circuit board includes
an insulating layer, a circuit layer embedded in the insulating
layer and having a connection pad that is embedded in the
insulating layer such that one side of the connection pad is flush
with a surface of the insulating layer, and insulating materials
configured to protect the circuit layer from an external
environment and having an opening through which the connection pad
is exposed. The printed circuit board is made slim, and reliability
and the degree of design freedom are increased.
Inventors: |
MOK; Jee Soo; (Gyunggi-do,
KR) ; Yoo; Je Gwang; (Gyunggi-do, KR) ; Ryu;
Chang Sup; (Gyunggi-do, KR) |
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Suwon
KR
|
Family ID: |
42318241 |
Appl. No.: |
13/474388 |
Filed: |
May 17, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12385003 |
Mar 27, 2009 |
8198550 |
|
|
13474388 |
|
|
|
|
Current U.S.
Class: |
29/846 |
Current CPC
Class: |
H05K 3/28 20130101; H05K
3/107 20130101; H05K 2201/0355 20130101; H05K 2203/1461 20130101;
Y10T 29/49155 20150115; H05K 2201/09481 20130101; H05K 3/4069
20130101; H05K 3/06 20130101; H05K 2201/0376 20130101; H05K 3/4647
20130101; Y10T 29/49144 20150115; H05K 2203/0278 20130101 |
Class at
Publication: |
29/846 |
International
Class: |
H05K 3/10 20060101
H05K003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 9, 2009 |
KR |
10-2009-0001971 |
Claims
1. A method of manufacturing a printed circuit board, comprising:
forming at least one circuit layer on a semi-cured insulating
layer, the circuit layer having a connection pad; forming
insulating materials on the insulating layer, the insulating
materials having an opening through which the connection pad is
exposed; and pressing and embedding the circuit layer and the
insulating materials into the insulating layer.
2. The method according to claim 1, wherein forming the at least
one circuit layer comprises: printing a first metal layer with a
bump; applying a semi-cured insulating layer on the first metal
layer printed with the bump; and applying a second metal layer on
the insulating layer and patterning the first and second metal
layers to form first and second circuit layers each having a
connection pad.
3. The method according to claim 1, wherein, in pressing and
embedding the circuit layer and the insulating materials, one side
of the connection pad, which is flush with the insulating layer,
acts as an exposed surface to which an external terminal is
bonded.
4. The method according to claim 1, wherein the insulating
materials are flush at one side with the insulating layer and are
embedded at the other side in the insulating layer.
5. The method according to claim 4, wherein the at least one
circuit layer is formed on the other side of the insulating
materials and is embedded in the insulating layer.
6. The method according to claim 4, wherein the at least one
circuit layer is embedded in the insulating materials.
7. The method according to claim 1, wherein, in pressing and
embedding the circuit layer and the insulating materials, the
pressing is executed while the insulating layer is in a semi-cured
state.
8. The method according to claim 1, wherein the insulating
materials are made of photosensitive insulating material.
9. The method according to claim 8, wherein forming the insulating
materials comprise: applying a photosensitive insulating material
on the insulating layer; and subjecting the photosensitive
insulating material to exposure and development processes to form
an opening through which the connection pad is exposed.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. divisional application filed
under 37 CFR 1.53(b) claiming priority benefit of U.S. Ser. No.
12/385,003, filed in the United States on Mar. 27, 2009, now
allowed, which claims earlier priority benefit to Korean Patent
Application No, 10-2009-0001971, filed Jan. 9, 2009, entitled "A
printed circuit board and a fabricating method the same", the
disclosures of which are incorporated herein by reference.
BACKGROUND
[0002] 1. Field
[0003] The present invention relates to a printed circuit board and
a method of manufacturing the printed circuit board.
[0004] 2. Description of the Related Art
[0005] Recently, demands for a technology which directly mounts a
semiconductor chip on a printed circuit board has been increasing
in response to the development of highly-densified semiconductor
chips and the high-speed transmission of signals. Consequently, the
development of printed circuit boards of a high density and high
reliability which are suitable to highly-densified semiconductor
chips is required.
[0006] Requirements for a printed circuit board of a high density
and reliability are closely related to the specifications of the
desired semiconductor chip. The printed circuit board having high
density and high reliability must further be developed to have many
characteristics such as the implementation of fine circuits,
excellent electrical properties, structure for high-speed
transmission of signals, high reliability, high performance,
slimness and the like. Accordingly, a technology for printed
circuit board which is capable of forming fine circuit patterns and
micro via-holes is required in order to meet these needs.
[0007] FIGS. 1 to 5 are cross-sectional views showing a
conventional process of manufacturing a printed circuit board. The
conventional process of manufacturing a printed circuit board will
now be described with reference to the drawings.
[0008] First, as shown in FIG. 1, a copper clad laminate which
comprises an insulating layer 12 and copper layers 14 disposed on
the insulating layer 12 is prepared.
[0009] As shown in FIG. 2, a via-hole 16 for the interlayer
electrical connection is formed in the copper clad laminate using
mechanical drilling or laser machining.
[0010] As shown in FIG. 3, a plated layer 18 is applied on the
inner wall of the via-hole 16 as well as the copper layer 14. In
this regard, the plated layer 18 includes an electroless plated
layer formed by an electroless plating process and an electrolytic
plated layer formed by an electrolytic plating process. For the
convenience of explanation, the plated layer 18 is shown in FIG. 3
as being composed of a single plated layer.
[0011] As shown in FIG. 4, the copper layer 14 and the plated layer
18 are patterned to create a circuit layer 20.
[0012] Finally, as shown in FIG. 5, a solder resist layer 22 having
an opening 24 through which a pad part of the circuit layer 20 is
exposed is disposed on the insulating layer 12, thus finishing a
printed circuit board 50.
[0013] The printed circuit board which is manufactured through the
conventional process is configured such that the circuit layer 20
including the pad part is formed on the insulating layer 12 and the
solder resist layer 22 for protecting the outermost circuit layer
20 is formed on the insulating layer 12. Consequently, the printed
circuit board 50 configured in this manner is problematic in that
its thickness is increased and reliability of the high density
circuit is deteriorated.
[0014] Furthermore, since the printed circuit board is configured
such that the pad part and the solder resist layer 50 are formed on
the insulating layer 12, stepped portions occur in the course of
machining the openings 24 through which the pad part is exposed,
thus making printability of external connection terminals uneven.
In addition, since the openings must be machined while taking into
consideration manufacturing error, the openings 24 are inevitably
made larger than the pad part, thus reducing a degree of freedom in
the design of the openings 24.
SUMMARY
[0015] Accordingly, the present invention has been made keeping in
mind the above problems occurring in the related art, and the
present invention provides a printed circuit board and a method of
manufacturing the same which enable configuration into a slim
structure and improving the reliability of a high-density
circuit.
[0016] Furthermore, the present invention provides a printed
circuit board and a method of manufacturing the same in which a
circuit layer and a solder resist layer are embedded in an
insulating layer such that there is no stepped portion between a
pad part and the solder resist layer, thus increasing a degree of
freedom of design.
[0017] In an aspect, the present invention provides a printed
circuit board including: an insulating layer; at least one circuit
layer embedded in the insulating layer and having a connection pad
that is embedded in the insulating layer such that one side of the
connection pad is flush with a surface of the insulating layer; and
a insulating materials configured to protect the circuit layer from
an external environment and having an opening through which the
connection pad is exposed.
[0018] The at least one circuit layer may include a first circuit
layer disposed on one side of the insulating layer and a second
circuit layer disposed on the other side of the insulating layer,
and the insulating layer may include a bump for connecting the
first circuit layer with the second circuit layer.
[0019] The one side of the connection pad which is flush with the
insulating layer may act as an exposed surface to which an external
terminal is bonded.
[0020] The insulating materials may be flush at one side with the
insulating layer and may be embedded at the other side in the
insulating layer.
[0021] The at least one circuit layer may be formed on the other
side of the insulating materials and may be embedded in the
insulating layer.
[0022] The at least one circuit layer may be embedded in the
insulating materials.
[0023] The insulating layer may include photosensitive insulating
material.
[0024] In another aspect, the present invention provides a method
of manufacturing a printed circuit board, including: (A) forming at
least one circuit layer on a semi-cured insulating layer, the
circuit layer having a connection pad; (B) forming insulating
materials on the insulating layer, the insulating materials having
an opening through which the connection pad is exposed; and (C)
pressing and embedding the circuit layer and the insulating
materials into the insulating layer.
[0025] The circuit layer may include: (A1) printing a first metal
layer with a bump; (A2) applying a semi-cured insulating layer on
the first metal layer printed with the bump; and (A3) applying a
second metal layer on the insulating layer and patterning the first
and second metal layers to form first and second circuit layers
each having a connection pad.
[0026] In (C) pressing and embedding the circuit layer and the
insulating materials, one side of the connection pad, which is
flush with the insulating layer, may act as an exposed surface to
which an external terminal is bonded.
[0027] The insulating materials may be flush at one side with the
insulating layer and may be embedded at the other side in the
insulating layer.
[0028] The at least one circuit layer may be formed on the other
side of the insulating materials and may be embedded in the
insulating layer.
[0029] The at least one circuit layer may be embedded in the
insulating materials.
[0030] In (C) pressing and embedding the circuit layer and the
insulating materials, the pressing may be executed while the
insulating layer is in a semi-cured state.
[0031] The insulating materials may be made of photosensitive
insulating material.
[0032] In the method, (B) forming the insulating materials may
include: (B1) applying a photosensitive insulating material on the
insulating layer; and (B2) subjecting the photosensitive insulating
material to exposure and development processes to form an opening
through which the connection pad is exposed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The above and other features and advantages of the present
invention will be more clearly understood from the following
detailed description taken in conjunction with the accompanying
drawings, in which:
[0034] FIGS. 1 to 5 are cross-sectional views showing a
conventional process of manufacturing a printed circuit board;
[0035] FIG. 6 is a cross-sectional view of a printed circuit board
according to an embodiment of the present invention; and
[0036] FIGS. 7 to 14 are cross-sectional views showing a process of
manufacturing the printed circuit board shown in FIG. 6.
DESCRIPTION OF EMBODIMENTS
[0037] Various advantages and features of the invention will become
apparent from the following description of embodiments with
reference to the accompanying drawings.
[0038] The terms and words used in the present specification and
claims should not be interpreted as being limited to typical
meanings or dictionary definitions, but should be interpreted as
having meanings and concepts relevant to the technical scope of the
present invention based on the rule according to which an inventor
can appropriately define the concept of the term to best describe
the method he or she knows for carrying out the invention.
[0039] Concerning the designations of reference numerals in this
description, it should be noted that the same reference numerals
are used throughout the different drawings to designate the same or
similar components. Also, in the description of the present
invention, when it is considered that the detailed description of a
related prior art may obscure the gist of the present invention,
such a detailed description is omitted.
[0040] Hereinafter, an embodiment of the present invention will be
described in greater detail with reference to the accompanying
drawings.
Printed Circuit Board
[0041] FIG. 6 is a cross-sectional view of a printed circuit board
according to an embodiment of the present invention. The printed
circuit board 100 according to this embodiment is described below
with reference to FIG. 6.
[0042] As shown in FIG. 6, the printed circuit board 100 according
to this embodiment comprises an insulating layer 106, circuit
layers 102a, 108a embedded in the insulating layer 106, and
insulating materials 110a, 110b embedded in the surface regions of
the insulating layer 106 to protect the circuit layers 102a, 108a
from the external environment.
[0043] The circuit layers 102a, 108a are configured such that the
first circuit layer 102a is formed on a side of the insulating
layer 106 and the second circuit layer 108a is formed on the other
side of the insulating layer 106. The first and second circuit
layers 102a, 108a are connected to each other via bumps 104 passing
through the insulating layer 106.
[0044] Connection pads of the circuit layers 102a, 108a are
embedded in the insulating layer 106 such that external surfaces of
the connection pads are flush with the external surfaces of the
insulating layer 106. Specifically, one side of the connection pad
is flush with the external surface of the insulating layer 106 to
offer an exposed surface to which an external connection terminal
such as solder ball is bonded, and the other side of the connection
pad is embedded in the insulating layer 106.
[0045] The insulating materials 110a, 110b are also embedded in the
insulating layer 106 such that external sides thereof are flush
with the external surfaces of the insulating layer 106 in order to
protect the first circuit layer 102a and/or the second circuit
layer 108a from the external environment. Specifically, one side of
each of the insulating materials 110a, 110b is flush with the
external surface of the insulating layer 106, and the other side of
the insulating materials is embedded in the insulating layer
106.
[0046] Furthermore, the circuit layers 102a, 108a excluding the
connection pads are also embedded in the insulating layer 106 so as
not to be exposed to the outside. In this context, there are two
manners in which the circuit layers 102a, 108a excluding the
connection pads may be embedded in the insulating layer 106 such
that the external surfaces thereof are disposed on the other sides,
i.e., internal surfaces of the insulating materials 110a, 110b for
the protection from the external environment (see FIG. 6) or they
are embedded in the insulating materials 110a, 110b (see FIG. 14).
In other words, the circuit layers 102a, 108a may have any embedded
configuration as long as the circuit layers 102a, 108a are
protected from the external environment by the insulating materials
110a, 110b. Although the circuit layers 102a, 108a are shown in
FIG. 14 as being entirely embedded in the insulating materials
110a, 110b, circuit layers which are at least partially embedded in
the insulating materials 110a, 110b should also be construed as
falling within the scope of the present invention.
[0047] In this embodiment, the insulating layers 110a, 110b may be
composed of photosensitive insulating material.
[0048] Although the printed circuit board 100 is shown in FIG. 6 as
having a two-layered structure, this is no more than a single
exemplary structure. Accordingly, it will be appreciated that the
scope of the present invention may include any of various
structures wherein a multilayered buildup layer is formed, a
connection pad formed on the outermost layer is embedded in an
insulating layer so as to be flush with an outermost insulating
layer, and an outermost circuit layer is protected by insulating
materials embedded in the outermost insulating layer.
Process of Manufacturing the Printed Circuit Board
[0049] FIGS. 7 to 14 are cross-sectional views showing a process of
manufacturing the printed circuit board shown in FIG. 6. The
process is described below with reference to the drawings.
[0050] First, as shown in FIG. 7, a first metal layer 102 is
prepared. As this first metal layer 102, a copper layer typically
used in the creation of a circuit layer of a printed circuit board
may be used.
[0051] As shown in FIG. 8, bumps 104 are formed on the first metal
layer 102.
[0052] In this regard, the bumps 104 may be formed using a screen
print technology. The screen print technology is executed in a
manner such that conductive paste is transferred to the metal layer
through openings of a mask. Specifically, openings of the mask are
aligned with the metal layer 102, and then conductive paste is
applied onto the mask. Subsequently, the conductive paste is wiped
using a squeegee, so that the conductive paste is extruded through
the openings of the mask and is then transferred to the first metal
layer 102 into a pattern having the desired shape and height. Of
course, it is to be noted that a process of forming the bumps 104
through any other of known technologies also falls within the scope
of the present invention.
[0053] The conductive paste that constitutes the bumps 104 may
include any conductive material, for example, one selected from
among Ag, Pd, Pt, Ni and Ag/Pd.
[0054] As shown in FIG. 9, an insulating layer 106 is applied onto
the first metal layer 102 on which the bumps 104 were formed.
[0055] At this point, the insulating layer 106 may be configured
such that its thickness is less than the height of the bumps 104,
and may be formed in a contact or noncontact way.
[0056] The process of contact way formation is executed in a manner
such that the insulating layer 106 is applied onto the first metal
layer 102 on which the bumps 104 were formed. At this point, the
bumps 104 may have a rigidity higher than that of the insulating
layer 106 such that the bumps 104 penetrate through the insulating
layer 106, and the insulating layer 106 may be embodied as a
semi-cured prepreg made of thermosetting resin. In this embodiment,
since the insulating layer 106 has a thickness less than the height
of the bumps 104, the bumps protrude from the insulating layer 106
by the difference therebetween.
[0057] The process of noncontact way formation is executed in a
manner such that the metal layer is coated with insulating resin
powder using an ink-jet print technology. This process is
advantageous in that it minimizes problems such as deformation of
the bumps and generation of fine gaps between the bumps 104 and the
insulating layer 16 which may otherwise occur in the process of the
contact way in which the bumps 104 are under pressure from the
insulating layer 106 while penetrating through the insulating layer
106.
[0058] As shown in FIG. 10, second metal layers 108 are applied
onto the insulating layer 106.
[0059] At this point, the second metal layer 108 is formed in a
manner such that the insulating layer 106 and the bumps 104 are
heated to a temperature higher than a softening temperature thereof
under a vacuum condition and are thus semi-cured, and then the
second metal layer 108 is pressed onto the semi-cured components
using a press plate such as a stainless steel plate with a flat
surface. By the pressing of the second metal layer 108, the second
metal layer 108 is connected to the bumps 104.
[0060] In this regard, since the second metal layer 108 is pressed
by the press plate having a flat surface, the pressure of the press
plate is evenly transmitted to the insulating layer 106, thus
preventing warping or twisting from occurring throughout the
substrate. Furthermore, since the pressing is executed under vacuum
conditions, there is no occurrence of voids in the insulating layer
106.
[0061] As shown in FIG. 11, the first metal layer 102 and the
second metal layer 108 are patterned to create a first circuit
layer 102a and a second circuit layer 108a each having a connection
pad.
[0062] At this point, the first circuit layer 102a and the second
circuit layer 108a may be created using a typical process such as a
subtractive process. Specifically, the first circuit layer 102a and
the second circuit layer 108a may be created in a manner such that
dry films are applied onto the first metal layer 102 and the second
metal layer 108 and then the first and second metal layers 102 and
108 are subjected to exposure, development and etching processes in
this order.
[0063] In this regard, the first circuit layer 102a and the second
circuit layer 108a are formed on the semi-cured insulating layer
106. The reason for this is because the first circuit layer 102a,
the second circuit layer 108a and insulating materials 110a, 110b
which are described below must be embedded in the insulating layer
106.
[0064] As shown in FIG. 12, the insulating materials 110a, 110b
having openings through which the insulating layer 106 is exposed
are formed on the insulating layer 106.
[0065] The insulating materials 110a, 110b, which are provided so
as to serve as solder resist layers for protecting the first and
second circuit layers 102a, 108a, may be made of a photosensitive
insulating material that has a higher reliability than a general
solder resist material and which allows for provision of openings
by a simple process. Specifically, this procedure may be
implemented by applying photosensitive insulating material 110a,
110b onto the insulating layer 106 and subjecting the
photosensitive insulating material to exposure and development
processes to form the openings through which the connection pads
are exposed.
[0066] Furthermore, the insulating materials 110a, 110b applied to
the insulating layer 106 may have a thickness exceeding that of the
first circuit layer 102a and the second circuit layer 108a so as to
protect the first and second circuit layer 102a, 108a from the
external environment.
[0067] Finally, as shown in FIG. 13, the first and second circuit
layers 102a, 108a including the connection pads and the insulating
materials 110a, 110b are pressed and are thus embedded in the
insulating layer 106.
[0068] At this point, the embedding procedure is implemented by
pressing the first and second circuit layers 102a, 108a and the
insulating materials 110a, 110b into the semi-cured insulating
layer 106 using a press plate such as a flat stainless steel
plate.
[0069] In this regard, the connection pads of the first and second
circuit layers 102a, 108a are embedded in the insulating layer 106
such that outer surfaces thereof are flush with the surface of the
insulating layer 106. In other words, one side of each of the
connection pads is flush with the surface of the insulating layer
106 and acts as an exposed surface on which an external connection
terminal such as a solder ball is bonded, and the other side of the
connection pad is embedded in the insulating layer 106.
[0070] The insulating materials 110a, 110b are also embedded in the
insulating layer 106 with their external surfaces flush with the
surface of the insulating layer 106. In other words, one side of
each of the insulating materials 110a, 110b is flush with the
surface of the insulating layer 106, and the other side of the
insulating materials is embedded in the insulating layer 106.
[0071] At this point, the first and second circuit layers 102a,
108a excluding the connection pads thereof are embedded in the
insulating layer 106 so as not to be exposed to the external
environment. In this procedure, the insulating materials 110a, 110b
may be deformed by the pressing force of the press plate and the
repulsion force of the insulating layer 106 against the pressing
force so that the first and second circuit layers 102a, 108a are
disposed on the internal surfaces of the insulating materials 110a,
110b. Alternatively, the insulating materials 110a, 110b and the
first and second circuit layers 102a, 108a may be embedded in the
insulating layer 106 without their initial configuration being
changed, as shown in FIG. 14. Although the first and second circuit
layers 102a, 108a are shown in FIG. 14 as being entirely embedded
in the insulating materials 110a, 110b, the first and second
circuit layers 102a, 108a may be partially embedded in the
insulating materials 110a, 110b.
[0072] Although the preferred embodiment of the present invention
has been disclosed for illustrative purposes, those skilled in the
art will appreciate that the printed circuit board and the method
of manufacturing the same are not limited thereto and that various
modifications, additions and substitutions are possible, without
departing from the scope and spirit of the invention as disclosed
in the accompanying claims. Accordingly, such modifications,
additions and substitutions should also be understood as falling
within the scope of the present invention.
* * * * *