U.S. patent application number 15/050606 was filed with the patent office on 2016-08-25 for circuit board and manufacturing method thereof.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. The applicant listed for this patent is SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Myung-Sam KANG, Young-Gwan KO, Jung-Han LEE, Tae-Hong MIN.
Application Number | 20160249445 15/050606 |
Document ID | / |
Family ID | 56690671 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160249445 |
Kind Code |
A1 |
MIN; Tae-Hong ; et
al. |
August 25, 2016 |
CIRCUIT BOARD AND MANUFACTURING METHOD THEREOF
Abstract
A circuit board is disclosed. In addition to insulating layers,
the circuit board includes a structure for heat transfer that
includes a first layer that is formed of graphite or graphene, a
second layer that is formed of metallic material and disposed on
one surface of the first layer, and a third layer that is formed of
metallic material and disposed on the other surface of the first
layer, and at least a portion of the structure for heat transfer is
inserted into an insulation layer. Such a circuit board provides
improved heat management. Also disclosed is a method of
manufacturing the circuit board.
Inventors: |
MIN; Tae-Hong; (Hwaseong-si,
KR) ; KANG; Myung-Sam; (Hwaseong-si, KR) ;
LEE; Jung-Han; (Seoul, KR) ; KO; Young-Gwan;
(Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRO-MECHANICS CO., LTD. |
Suwon-si |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
56690671 |
Appl. No.: |
15/050606 |
Filed: |
February 23, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K 1/181 20130101;
H05K 2201/10416 20130101; H05K 3/4608 20130101; H05K 1/0206
20130101; H05K 1/0203 20130101; H05K 1/0207 20130101; H05K 2201/066
20130101; H05K 1/0218 20130101; H05K 1/111 20130101; H05K 2201/0338
20130101; H05K 1/183 20130101; H05K 1/0204 20130101; H05K 2201/0323
20130101 |
International
Class: |
H05K 1/02 20060101
H05K001/02; H05K 1/11 20060101 H05K001/11 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2015 |
KR |
10-2015-0025166 |
Claims
1. A circuit board, comprising: insulation layers; a structure for
heat transfer, wherein at least a portion of the structure for heat
transfer is inserted into at least a portion of the insulation
layers; metal layers; and vias that penetrate at least one of the
insulation layers to connect at least two of the metal layers,
wherein the structure for heat transfer comprises a first layer,
formed of graphite or graphene, a second layer, located on one
surface of the first layer and formed of metallic material, and a
third layer, located on the other surface of the first layer and
formed of metallic material, wherein a boundary surface between the
first layer and the second layer or a boundary surface between the
first layer and the third layer is perpendicular to a boundary
between the insulation layers.
2. The circuit board of claim 1, further comprising penetration
holes that penetrate through the first layer and are filled with
the same metallic material as the metallic material that forms the
second layer and the third layer.
3. The circuit board of claim 2, wherein the second layer, the
third layer and the metallic material that is filled in the
penetration holes are formed in an integrated manner.
4. The circuit board of claim 1, wherein an XY plane of graphite or
graphene is formed in parallel with the boundary surface between
the first layer and the second layer.
5. The circuit board of claim 4, wherein the first layers are
arranged to be spaced apart from each other so as to form the
structure for heat transfer.
6. The circuit board of claim 1, further comprising: a first
insulation layer, comprising a cavity into which at least a portion
of the structure for heat transfer is inserted; a first via,
penetrating a second insulation layer that is located above the
first insulation layer; a second via, penetrating a third
insulation layer that is located below the first insulation layer;
a first metal pattern, located on an outer surface of the second
insulation layer and in contact with one end of the first via; and
a second metal pattern, located on an outer surface of the third
insulation layer and in contact with one end of the second via,
wherein the boundary surface between the first layer and the second
layer and the boundary layer between the first layer and the third
layer are perpendicular to the boundary surface between the first
insulation layer and the second insulation layer.
7. A circuit board, comprising: insulation layers; a structure for
heat transfer, wherein at least a portion of the structure for heat
transfer is inserted into at least a portion of the insulation
layers; metal layers; and vias that penetrate at least one of the
plurality of insulation layers to connect at least two of the metal
layers, wherein the structure for heat transfer comprises a first
layer, formed of graphite or graphene and comprising penetration
holes, and a second layer and a third layer, located on one surface
and the other surface of the first layer respectively and formed of
metallic material.
8. The circuit board of claim 7, wherein a boundary surface between
the first layer and the second layer or a boundary surface between
the first layer and the third layer is formed to be parallel with a
boundary between the insulation layers.
9. The circuit board of claim 8, wherein an XY plane of graphite or
graphene is in parallel with the boundary surface between the first
layer and the second layer.
10. The circuit board of claim 7, wherein the second layer, the
third layer, and the metallic material that is filled in the
penetration holes are formed in an integrated manner.
11. A method of manufacturing a circuit board, comprising forming
the circuit board such that the circuit board comprises insulation
layers and a structure for heat transfer, wherein at least a
portion of the structure for heat transfer is inserted into at
least a portion of the insulation layers, metal layers, and vias
that penetrate at least one of the insulation layers to connect at
least two of the metal layers, wherein the structure for heat
transfer is formed by providing a first layer that is formed of
graphite or graphene and comprises penetration holes, and forming a
second layer and a third layer by providing metallic material to
one surface and the other surface of the first layer and the
penetration holes.
12. The method of claim 11, wherein a boundary surface between the
first layer and the second layer or a boundary surface between the
first layer and the third layer is formed to be perpendicular to a
boundary between the insulation layers
13. The method of claim 11, wherein a boundary surface between the
first layer and the second layer or a boundary surface between the
first layer and the third layer is formed to be parallel with a
boundary between the insulation layers.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit under 35 USC 119(a) of
Korean Patent Application No. 10-2015-0025166 filed on Feb. 23,
2015 in the Korean Intellectual Property Office, the entire
disclosure of which is incorporated herein by reference for all
purposes.
BACKGROUND
[0002] 1. Field
[0003] The following description relates to a circuit board. The
following description also relates to a method of manufacturing
such a circuit board.
[0004] 2. Description of Related Art
[0005] In accordance with a trend toward light weight,
miniaturization, increased speed, multi-functional operation, and
improvements in performance of electronic devices, multilayered
substrate technologies in which a plurality of wiring layers are
formed on a printed circuit board (PCB) have been developed.
Furthermore, technologies in which electronic components such as
active elements, passive elements, or other appropriate electronic
components, are embedded in a multilayered substrate have also been
developed.
[0006] As an application processor (AP) that is connected to the
multilayered substrate becomes multi-functional and achieves
high-performance operation, the heat generation amount produced by
the AP increases significantly.
SUMMARY
[0007] This Summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the Detailed Description. This Summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used as an aid in determining the scope of
the claimed subject matter.
[0008] In one general aspect, a circuit board includes insulation
layers, a structure for heat transfer, wherein at least a portion
of the structure for heat transfer is inserted into at least a
portion of the insulation layers, metal layers, and vias that
penetrate at least one of the insulation layers to connect at least
two of the metal layers, wherein the structure for heat transfer
includes a first layer, formed of graphite or graphene, a second
layer, located on one surface of the first layer and formed of
metallic material, and a third layer, located on the other surface
of the first layer and formed of metallic material, wherein a
boundary surface between the first layer and the second layer or a
boundary surface between the first layer and the third layer is
perpendicular to a boundary between the insulation layers.
[0009] The circuit board may further include penetration holes that
penetrate through the first layer and are filled with the same
metallic material as the metallic material that forms the second
layer and the third layer.
[0010] The second layer, the third layer and the metallic material
that is filled in the penetration holes may be formed in an
integrated manner.
[0011] An XY plane of graphite or graphene may be formed in
parallel with the boundary surface between the first layer and the
second layer.
[0012] The first layers may be arranged to be spaced apart from
each other so as to form the structure for heat transfer.
[0013] The circuit board may further include a first insulation
layer, including a cavity into which at least a portion of the
structure for heat transfer is inserted, a first via, penetrating a
second insulation layer that is located above the first insulation
layer, a second via, penetrating a third insulation layer that is
located below the first insulation layer, a first metal pattern,
located on an outer surface of the second insulation layer and in
contact with one end of the first via, and a second metal pattern,
located on an outer surface of the third insulation layer and in
contact with one end of the second via, wherein the boundary
surface between the first layer and the second layer and the
boundary layer between the first layer and the third layer are
perpendicular to the boundary surface between the first insulation
layer and the second insulation layer.
[0014] In another general aspect, a circuit board includes
insulation layers, a structure for heat transfer, wherein at least
a portion of the structure for heat transfer is inserted into at
least a portion of the insulation layers, metal layers, and vias
that penetrate at least one of the plurality of insulation layers
to connect at least two of the metal layers, wherein the structure
for heat transfer includes a first layer, formed of graphite or
graphene and including penetration holes, and a second layer and a
third layer, located on one surface and the other surface of the
first layer respectively and formed of metallic material.
[0015] A boundary surface between the first layer and the second
layer or a boundary surface between the first layer and the third
layer may be formed to be parallel with a boundary between the
insulation layers.
[0016] An XY plane of graphite or graphene may be in parallel with
the boundary surface between the first layer and the second
layer.
[0017] The second layer, the third layer, and the metallic material
that is filled in the penetration holes may be formed in an
integrated manner.
[0018] In another general aspect, a method of manufacturing a
circuit board includes forming the circuit board such that the
circuit board includes insulation layers and a structure for heat
transfer, wherein at least a portion of the structure for heat
transfer is inserted into at least a portion of the insulation
layers, metal layers, and vias that penetrate at least one of the
insulation layers to connect at least two of the metal layers,
wherein the structure for heat transfer is formed by providing a
first layer that is formed of graphite or graphene and includes
penetration holes, and forming a second layer and a third layer by
providing metallic material to one surface and the other surface of
the first layer and the penetration holes.
[0019] A boundary surface between the first layer and the second
layer or a boundary surface between the first layer and the third
layer may be formed to be perpendicular to a boundary between the
insulation layers.
[0020] A boundary surface between the first layer and the second
layer or a boundary surface between the first layer and the third
layer may be formed to be parallel with a boundary between the
insulation layers.
[0021] Other features and aspects will be apparent from the
following detailed description, the drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1A is a cross-sectional view schematically showing a
circuit board according to an example.
[0023] FIG. 1B is a perspective view schematically showing one
example of the first structure for heat transfer according to an
example.
[0024] FIG. 1C is a perspective view schematically showing another
example of the first structure for heat transfer according to an
example.
[0025] FIG. 1D is a perspective view schematically showing still
another example of the first structure for heat transfer according
to an example.
[0026] FIG. 1E is a perspective view schematically showing still
another example of the first structure for heat transfer according
to an example.
[0027] FIG. 1F is a perspective view schematically showing still
another example of the first structure for heat transfer according
to an example.
[0028] FIG. 1G is a perspective view schematically showing still
another example of the first structure for heat transfer according
to an example.
[0029] FIG. 2 is a cross-sectional view schematically showing a
circuit board 100 according to another example.
[0030] FIG. 3 illustrates a plan view of circuit board 100
according to an example.
[0031] FIG. 4 illustrates a horizontal cross-sectional view of
circuit board 100 according to an example.
[0032] FIG. 5 illustrates a horizontal cross-sectional view of
circuit board 100 according to another example.
[0033] FIG. 6 is a partially enlarged view showing a main component
of circuit board 100 according to an example.
[0034] FIG. 7 illustrates the second structure for heat transfer
according to an example.
[0035] FIG. 8 illustrates the second structure for heat transfer
according to another example.
[0036] FIG. 9 illustrates the second structure for heat transfer
according to still another example.
[0037] FIG. 10A shows the reflow test result that is performed
during the time period in which the primer layer 111 is situated on
the surfaces of the structure for heat transfer.
[0038] FIG. 10B shows the solder pot test result that is performed
during the time period in which the primer layer 111 is disposed on
the surfaces of the structure for heat transfer.
[0039] FIG. 11A shows the reflow test result that is performed
during the time period in which the insulation part 120 is in
direct contact with the structure for heat transfer.
[0040] FIG. 11B shows the solder pot test result that is performed
during the time period in which the insulation part 120 is in
direct contact with the structure for heat transfer.
[0041] FIG. 12 illustrates a method of manufacturing the first
structure for heat transfer according to an example.
[0042] FIG. 13 illustrates a method of manufacturing the first
structure for heat transfer according to an example.
[0043] FIG. 14A illustrates a method of manufacturing the first
structure for heat transfer according to an example.
[0044] FIG. 14B illustrates a method of manufacturing the first
structure for heat transfer according to another an example.
[0045] FIG. 15 illustrates a method of manufacturing the first
structure for heat transfer according to still another an
example.
[0046] Throughout the drawings and the detailed description, the
same reference numerals refer to the same elements. The drawings
may not be to scale, and the relative size, proportions, and
depiction of elements in the drawings may be exaggerated for
clarity, illustration, and convenience.
DETAILED DESCRIPTION
[0047] The following detailed description is provided to assist the
reader in gaining a comprehensive understanding of the methods,
apparatuses, and/or systems described herein. However, various
changes, modifications, and equivalents of the methods,
apparatuses, and/or systems described herein will be apparent to
one of ordinary skill in the art. The sequences of operations
described herein are merely examples, and are not limited to those
set forth herein, but may be changed as will be apparent to one of
ordinary skill in the art, with the exception of operations
necessarily occurring in a certain order. Also, descriptions of
functions and constructions that are well known to one of ordinary
skill in the art may be omitted for increased clarity and
conciseness.
[0048] The features described herein may be embodied in different
forms, and are not to be construed as being limited to the examples
described herein. Rather, the examples described herein have been
provided so that this disclosure will be thorough and complete, and
will convey the full scope of the disclosure to one of ordinary
skill in the art.
[0049] Hereinafter, configurations and effects of the present
examples are described in further detail with reference to the
accompanying drawings.
[0050] FIG. 1A is a cross-sectional view schematically showing a
circuit board according to an example. FIGS. 1B through 1G are
perspective views schematically showing various examples of the
first structure for heat transfer according to an example.
[0051] Further, FIG. 2 is a cross-sectional view schematically
showing a circuit board 100 according to another example. FIG. 3
illustrates a plan view of circuit board 100 according to an
example. FIG. 4 illustrates a horizontal cross-sectional view of
circuit board 100 according to an example. FIG. 5 illustrates a
horizontal cross-sectional view of circuit board 100 according to
another example. FIG. 6 is a partially enlarged view showing a main
component of circuit board 100 according to an example. FIG. 7
illustrates the second structure for heat transfer according to an
example. FIG. 8 illustrates the second structure for heat transfer
according to another example. FIG. 9 illustrates the second
structure for heat transfer according to still another example.
[0052] For example, the circuit board 100 according to an example
includes the first structure for heat transfer 110, and at least a
portion of the first structure for heat transfer 110 is inserted in
an insulation part 120. The first structure for heat transfer 110
is formed of a highly thermally conductive material. Also, the
first structure for heat transfer 110 is formed in the shape of a
lump. For example, in one example, the first structure for heat
transfer 110 is formed in the shape of a circular pillar or a
polygonal pillar having an upper surface and a lower surface. In
such an example, the first structure for heat transfer 110 is
formed of a metallic material such as a copper (Cu) or another
metal or metallic alloy with similar properties. In another
example, the first structure for heat transfer 110 is formed of a
non-metallic material with a high thermal conductivity such as
graphite, graphene, or the like. However, it will be recognized
that while the first structure for heat transfer 110 is potentially
made of different materials in different examples, the material
that is chosen should have good thermal conductivity.
[0053] Referring to the examples of FIGS. 1A through 1G, the first
structure for heat transfer 110 is formed by interposing a layer
that is made of graphite or graphene between layers that are formed
of the metallic material.
[0054] Subsequently, a layer that is formed of graphite or graphene
is referred to as the first layer 119, and a layer that is formed
of metallic material is referred to as the second layer 118-1 and
the third layer 118-2.
[0055] Conventionally, graphite or graphene is formed to have a
plate shape structure in which carbon atoms are connected to each
other, and these plate shape structures are stacked together in a
plurality of layers. A plane in which carbon atoms form the plate
shape structure is referred to as an XY plane, and a direction in
which a plurality of plate shape structures are stacked is referred
to as a Z-axis direction. Graphite or graphene has a relatively
high heat conductivity compared to any metallic material such as
copper, and further has an especially higher heat conductivity in
an XY plane direction than in a Z-axis direction.
[0056] Thus, as shown in the examples of FIGS. 1B through 1D, in a
case that the first layer 119 is arranged in a vertical direction,
the heat conductivity between the upper surface and the lower
surface of the first structure for heat transfer 110 is potentially
improved. In particular, in an example in which an XY plane of
graphite or graphene is arranged in the vertical direction, the
heat conductivity in the vertical direction is further improved.
Accordingly, the heat that the first electronic component 500
generates is rapidly dissipated in a downwards direction through
the first structure for heat transfer 110.
[0057] Also, as shown in the examples of FIGS. 1E through 1G, in an
example in which the first layer 119 is arranged in the horizontal
direction, the heat conductivity of the first structure for heat
transfer 110 in the lateral direction, namely, in the horizontal
direction, is possibly improved further. Especially, in an example
in which the XY plane of graphite or graphene is arranged in the
horizontal direction, the heat conductivity in the horizontal
direction is further improved. Accordingly, the heat that the first
electronic component 500 generates is transferred to the first
structure for heat transfer 110 and then rapidly dissipated in the
lateral direction. Also, in an example in which the first core
layer 11 is formed to include an element for heat transfer in the
horizontal direction in the circuit board 100, for example, such
that a second structure for heat transfer is provided, it is
further advantageous for improving the heat dissipation property.
Also, the second structure for heat transfer is described further
later.
[0058] For example, the first structure for heat transfer 110 is
formed by situating the second layer 118-1 on one surface of the
first layer 119 and the third layer 118-2 on the other surface of
the third layer 118-2 of metallic material.
[0059] However, a plurality of constituent layers that form the
first layer 119, such as constituent layers 119-1, 119-2, 119-3,
are optionally disposed on the first structure for heat transfer
110, if needed.
[0060] Compared to the metallic material that forms the other
layers, the graphite or the graphene that forms the first layer 119
has the heat conductivity that is relatively larger than that of
the metallic material such as copper. Accordingly, if the number of
the first layers increase, the heat transfer property of the first
structure of heat transfer 110 is further improved by the increase
in use of a material with better heat conductivity
characteristics.
[0061] However, since vias V1, V2 that are in contact with the
first structure for heat transfer 110 are formed to transfer
electrical signals, the thickness or the number of constituent
layers of the first layer 119 is potentially determined based on a
volume, a shape, and thickness of the first structure for managing
heat transfer and effective circuit wiring.
[0062] On the other hand, however, the hardness of graphite or
graphene is relatively low compared to that of the metallic
material. Especially in a case of graphite or graphene that is
formed by stacking plate shape structures, the bonding power
between stacked plates of graphite or graphene is relatively low.
Also, because the first layer 119 and the second and the third
layer 118-1 and 118-2 are formed of different materials, the
bonding power on the boundary surface is relatively weakened, due
to a lack of adhesion between the layers.
[0063] However, in a circuit board according to an example, the
metallic material that penetrates the first layer 119 is formed
integrally as a single unit with the metallic material that forms
the second layer 118-1 and the third layer 118-2. As a result, the
reliability of the first structure for heat transfer 110 is
possibly improved. That is, the bonding power between plate
structures of graphite or graphene that forms the first layer 119
is improved by using such an approach, and the bonding power or the
adhesion strength of the boundary surface between the first layer
119 and the second and the third layers 118-1, 118-2 that are
formed of different materials is also accordingly improved. Here, a
hole that penetrates the first layer 119 is referred to as a
through hole 119H.
[0064] The undescribed reference numerals 118-3 and 118-4 indicate
additional layers that are formed of the metallic material.
[0065] In an example, the insulation part 120 is formed of one
insulation layer or a plurality of insulation layers. In such an
example, the insulation part 120 illustrated in FIG. 1A includes
three insulation layers 10, 121, 121', and the insulation layer
that is disposed on the center portion is the core part 10.
However, this is merely an example and examples are not limited to
such an arrangement.
[0066] In an example, the first structure for heat transfer 110 is
situated in the middle of the insulation part 120. In such an
example, in which the core part 10 is disposed as shown, a cavity
C1 that penetrates the core part 10 is formed and the first
structure for heat transfer 110 may be inserted in cavity C1.
[0067] In an example, vias that are formed in the insulation layer
120 are in contact with the first structure for heat transfer 110.
Subsequently, the via that is formed on an upper portion of the
first structure for heat transfer 110 is referred to as the first
via V1, and the via that is formed on a lower portion of the first
structure for heat transfer 110 is referred to as the first via V2.
At least one metal pattern is situated on the insulation part 120,
and subsequently, the metal pattern that is in contact with the
first via V1 is referred to as the first metal pattern 131. The
metal pattern that is in contact with the second via V2 is referred
to as the second metal pattern 141. Also, the fourth via V4 and the
fifth via V5 are potentially further disposed in the insulation
part 120. The metal pattern that is contacted with the fourth via
V4 is referred to as the third metal pattern 133, and the metal
pattern that is contacted with the fifth via V5 is referred to as
the fourth metal pattern 142.
[0068] In an example, the first structure for heat transfer 110
performs a function of keeping heat, and this function increases as
the volume of the first structure for heat transfer increases. As
shown in the examples of FIGS. 1A through 1G, the first structure
for heat transfer 110 is formed in the cylindrical shape. As it is
formed in a pillar shape in these examples, the volume of the first
structure for the heat transfer 110 is maximized if the area of the
lower surface is chosen accordingly. Also, if the shape of the
lower and the upper surfaces of the first structure for heat
transfer 110 is polygonal, especially rectangular, the first
structure for heat transfer potentially satisfies the
miniaturization goal of the first electronic component 500 or the
miniaturization of circuit board 100, fine pattern pitch, or
another miniaturization requirement. Also, as shown, the first
structure for heat transfer 110 has a volume that is far larger
than the alternative vias such as the first via V1 through the
seventh V7. Accordingly, the vias of a plurality of vias are in
contact with surfaces, especially the upper surface or the lower
surface of the first structure for heat transfer 110. That is, the
area of the upper surface and the lower surface of the first
structure for heat transfer 110 themselves are larger than the
alternative vias. Also, the entire volume of the first structure
for heat transfer 110 is also more than double than that of an
alternative structure. As a result, the first structure for heat
transfer 110 is able to rapidly absorb the heat from a heat source,
and to dissipate the heat using other routes that are connected to
the first structure for heat transfer 110. Also, when the thickness
of the first structure for heat transfer 110 is increased, the
distance between the first structure for heat transfer 110 and the
hot spot is accordingly decreased so that a time for the heat to
flow to the first structure for heat transfer 110 is shortened.
[0069] In one example, the first electronic component 500 is
mounted on one surface of the circuit board 100. Also, in an
example, the circuit board 100 is mounted on one surface of an
additional board 800 such as a main board. For example, the first
electronic component 500 is an electronic part, such as an
application processor, and generates heat during its operation.
[0070] When the first electronic component 500 operates, the heat
is generated. However, when detecting the heat that the first
electronic component 500 generates, there is a region in which more
heat is generated than other regions. This region is referred to as
a hot spot. Such a hot spot is formed on a predetermined region of
the circuit board 100. For example, the hot spot is formed on one
or more points, having the first electronic component 500 as the
center. Also, these hot spots are potentially formed around a power
terminal of the first electronic component 500, or in a region in
which switching elements are relatively concentrated due to the
increased heat generation in these areas.
[0071] In an example, the first electronic component 500 includes a
relatively high performance region and a relatively low performance
region. For example, one processor that consists of cores operating
at 1.8 GHz and another processor that consists of cores operating
at 1.2 GHz are arranged in different regions of the first
electronic component. Referring to the example of FIG. 3, the first
electronic component 500 includes the first unit region 510 and the
second unit region 520. The first unit region 510 operates at
higher speed than the second unit region 520. Hence, the first
region 510 consumes much more power than the second unit region 520
does. Accordingly, the first unit region 510 generates much more
heat than the second unit region 520 does as waste heat from the
processing at a higher power.
[0072] In the circuit board 100 according to an example, the first
structure for heat transfer 110 is disposed adjacent to the hot
spot. Accordingly, the first structure for heat transfer 110
rapidly receives the heat from the hot spot to dissipate to other
regions of the circuit board 100 or other devices such as main
board, such as, for example, the additional board 800 in FIG. 1A,
on which the circuit board is mounted.
[0073] In an example, at least a portion of the first structure for
heat transfer 110 is situated below the first electronic component
500.
[0074] The circuit board 100 according to an example potentially
further includes the second electronic component 200. In examples
the second electronic component 200 is a capacitor, an inductor, a
resistor, or a similar component used as part of an electronic
circuit.
[0075] In an example, that the first electronic component 500 is
the application processor, the first electronic component 500 is
optionally connected to the capacitor in order to reduce a power
noise. In such an example, it is potentially helpful to choose a
distance between the capacitor and the first electronic component
that is relatively short in order to increase the noise reduction
effect.
[0076] Accordingly, at least a portion of the second electronic
component 200 is situated below the first electronic component 500.
As a result, the noise reduction effect is increased.
[0077] In an example, almost all portions of the first structure
for heat transfer 110 are situated at the region below the first
electronic component 500. Also, an area of the upper surface of the
first structure for heat transfer 110 is possibly smaller than the
area of the upper surface of the first electronic component 500.
Furthermore, in such an example, the area of the upper surface of
the first structure for heat transfer 110 is determined to
correspond to a width of hot spot region of the first electronic
component 500.
[0078] Accordingly, the heat from the hot spot is rapidly
transferred to the first structure for heat transfer 110. Also,
such an approach is advantageous for a lighter weight of the
circuit board 100 and also a circuit board 100 that reduces
warping. In addition, it increases an efficiency of processing to
situate the first structure for heat transfer 110 on the circuit
board 100.
[0079] In an example, almost all portions of the second electronic
component 200 are situated at the region below the first electronic
component 500. The second electronic component 200 is situated at
the region below the first electronic component 500, where the
first structure for heat transfer 110 is not situated. Also, by
comparison to the second electronic component 200, the first
structure for heat transfer 110 is situated nearer to the hot
spot.
[0080] Referring to FIGS. 1A through 1G and FIGS. 2 through 4, it
is to be understood that, in an example, the first structures for
heat transfer 110 and the second electronics components 200 are
inserted in cavities C1, C2 in the core part 10. The first cavity
C1 and the second cavity C2 are formed in the core part 10. In such
an example, the first structure for heat transfer 110 is inserted
into the first cavity C1 and the second electronic component 200 is
inserted into the second cavity C2. It is to be understood in this
example that at the region below the first electronic component
500, the first structures for heat transfer 110 and the second
electronic components 200 are situated adjacent to each other, and
in particular, the first structures for heat transfer 110 are
situated intensively around the hot spot, which is illustrated in
FIGS. 3-4. FIG. 5 illustrates schematically a plan view in an
example in which there is no core part 10 in the insulation part
120.
[0081] Accordingly, by using these approaches, it becomes possible
to maximize the power noise reduction by the second electronic
component 200 and to transfer the heat that is generated at the hot
spot.
[0082] In an example, the first electronic component 500 is coupled
to the circuit board 100 by means of a solder (S) or a similar
binder that attaches these two elements together. For example, the
first electronic component 500 is coupled to the first metal
pattern 131, the third metal pattern 133, the seventh metal pattern
134, and so on, by means of solder (S) or an alternative
binder.
[0083] Also, the second metal pattern 141, the fourth metal pattern
142, the fifth metal pattern 143, the sixth metal pattern 144, and
so on, are coupled to the additional board 800, such as a main
board, by means of solder (S). In an example, rather than an
alternative solder, the third structure for heat transfer L1 that
is formed of a similar material and in a similar shape to the first
structure for heat transfer 110, is interposed between the second
metal pattern 141 and the additional board 800. In order to
transfer heat of the first structure for heat transfer 110 to the
additional board 800, the third structure for heat transfer L1,
which is formed of material having higher heat conductivity than
the conventional solder and is formed to have a lump shape, is used
for coupling the second metal pattern 141 and the additional board
800 to one another. In addition, in order to rapidly receive heat
of the third structure for heat transfer L1 and to dissipate such
heat, a heat radiation part L2 is situated in the additional board
800. The heat radiation part L2 is exposed in the direction of the
upper surface of the additional board 800, and is also exposed in
the direction of the lower surface of the additional board 800 to
increase the heat radiation efficiency, if desired.
[0084] A metal pattern, which is situated at the outer part of the
board so as to be connected to other electronic components, for
example, the first electronic component 500 or the additional board
800, is referred to as a pad. Various circuit patterns as well as
pads are situated on the outermost metal layer, and a solder resist
layer, not shown, is optionally situated so as to protect the
circuit pattern or the insulation part 120. At least a portion of
pads for connecting to the external device are exposed to the
outside of such a solder resist layer. In an example, the pad that
is exposed to the solder resist layer and the terminal of the
external device are physically coupled to each other by a coupling
means, such as solder or wire, not shown.
[0085] As illustrated in the example of FIG. 1, in an example that
the first through the seventh metal patterns are exposed to the
outer surface of the insulation part 120, the first through the
seventh metal patterns are considered to be the aforementioned
pads. In addition, various surface processed layers such as a
nickel-gold plating layer are optionally situated on surfaces of
the metal patterns that are exposed to the outside of the solder
resist layer.
[0086] Although not shown, an insulation layer that covers the
outer surface of the first metal pattern 131 and a pad that is
formed on the outer surface of the insulation layer are optionally
further situated, and the first metal pattern 131 and the pad is
connected by a via that penetrates through the insulation layer.
That is, a built-up layer including the insulation layer and the
metal layer is further situated, if desired or required. In such an
example, the aforementioned metal pattern 131 is no longer a pad,
and is connected to the pad that is formed on the outmost metal
layer of the circuit board by means of a via or a similar
connector.
[0087] Accordingly, heat that is generated at the hot spot is
rapidly transferred to the additional board 800 through a route
starting at the first metal pattern 131, then progressing through
the first via V1, then the first structure for heat transfer 110,
then the second via V2 then the second metal pattern 141 as its
transfer route.
[0088] Alternatively, in an example in which a contact that is to
be connected to the first metal pattern among contacts of the first
electronic component 500 is a terminal for transmitting signals,
the route starting at the first via V1, then progressing through
the first structure for heat transfer 110, then the second via V2,
then the second metal pattern 141 performs a function of
transmitting signals. The contact pads or terminals of the
additional board 800 that are to be connected to the second metal
pattern 141 also potentially perform the function of transmitting
signals.
[0089] In an example in which a contact that is to be connected to
the first metal pattern among contacts of the first electronic
component 500 is not a terminal for transmitting signals, the route
of starting at the first via V1, then progressing through the first
structure for heat transfer 110, then the second via V2, then the
second metal pattern 141 is electrically connected to a ground
terminal, not shown. The contact pads or terminals of the
additional board 800 that is to be connected to the second metal
pattern 141 are also potentially electrically connected to the
ground terminal. In this example, the ground terminal is situated
on at least one of the circuit board 100 and the additional board
800.
[0090] In an example that a contact that is to be connected to the
first metal pattern among contacts of the first electronic
component 500 is a power terminal, the route starting at the first
via V1, then progressing through the first structure for heat
transfer 110, then the second via V2, then the second metal pattern
141 is electrically connected to a power providing circuit, not
shown. The contact pads or terminals of the additional board 800 to
be connected to the second metal pattern 141 are also electrically
connected to the power providing circuit. In this example, the
power providing circuit is situated on at least one of the circuit
board 100 and the additional board 800.
[0091] In an example, a contact that is to be connected to the
first metal pattern among contacts of the first electronic
component 500 is a dummy terminal. In such an example, the dummy
terminal is used as a passage for transferring heat to the outside
of the first electronic component 500.
[0092] As described above, terminals of the first electronic
component 500 are divided into terminals for signal input/output, a
terminal for power input/output, and a terminal for heat radiation.
It is to be noted that a certain terminal potentially performs more
than one function. That is, a terminal is potentially used for heat
radiation as well as power input/output. However, once terminals
that are disposed at the hot spot of the first electronic component
500 performs the heat radiation function, heat of the hot spot is
more rapidly dissipated. By placing the terminal for heat radiation
in contact with the first coupling means and placing the first
coupling means in contact with the first metal pattern 141, the
heat movement between the hot spot and the first structure for heat
transfer 110 is made to be much smoother.
[0093] In an example, at least one terminal of the first electronic
component 500 that is to be electrically connected to the first
structure for heat transfer 110 is a dummy terminal that is
dedicated for the heat radiation. If a terminal used only for
signal input/output among terminals of the first electronic
component 500 is connected to the first structure for heat transfer
110, a signal loss possibly occurs. Thus, in an example the
terminal for signal input/output is not electrically connected to
the first structure for heat transfer 110. That is, a via or a
circuit pattern that is connected to a pad in order to be connected
to the terminal only for signal input/output among terminals of the
first electronic component 500 is not electrically connected to the
first structure for heat transfer 110 based on this rationale.
[0094] Referring to FIGS. 1A through 9, the circuit board 100
according to an example includes the core part 10. For example, the
core part 10 reinforces a rigidness of the circuit board 100 in
order to relieve a problem that occurs due to the warping. In
addition, by including a material with high heat conductivity in
the core part 10, heat that is generated at a local region such as
a hot spot is rapidly dissipated to other regions of the circuit
board 100 in order to relieve a problem due to overheating.
[0095] The first upper insulation layer 121 is situated on the
upper surface of the core part 10, and the first lower insulation
layer 121' is situated on the lower surface of the core part 10. In
addition, the second upper insulation layer 122 and the second
lower insulation layer 122' are further situated appropriately.
[0096] In one example, the core part 10 includes the second
structure for heat transfer. For example, the core part 10 includes
the first core layer 11 that is made of graphite or graphene. As
discussed previously, graphite or graphene has relatively high heat
conductivity in an XY plane direction. As a result, graphite or
graphene dissipates heat effectively and rapidly.
[0097] In an example, the second structure for heat transfer is in
direct contact with a side surface of the first structure for heat
transfer 110. For example, a side surface of the second structure
for heat transfer is exposed to the first cavity C1 that is formed
in the core part 10. Also, the first structure for heat transfer
110 is in contact with the first cavity C1. In another example, a
highly thermally conductive material is interposed between the
second structure for heat transfer and the first structure for heat
transfer 110. For example, Terminal Interface Material (TIM) is
applied as the highly thermally conductive material. In examples,
such a TIM includes polymer-metal composite material, ceramic
composite material, carbon-based composite material, or a similar
appropriate material, where these enumerated materials are merely
examples. For example, a mixture of epoxy and carbon fiber filler,
with a heat conductivity of about 660 W/mk, Silicon Nitride
(Si.sub.3N.sub.4), with a heat conductivity of about 200-320 W/mk,
a mixture of epoxy and Boron Nitride (BN), with a heat conductivity
of about 19 W/mk, or another appropriate material is applied as a
TIM. Accordingly, heat that is transferred into the first structure
for heat transfer 110 is rapidly dissipated in the horizontal
direction by using the second structure for heat transfer as well
as in the vertical direction, as previously discussed further.
[0098] Because the first structure for heat transfer 110 and the
second structure for heat transfer are in contact with each other
directly or by means of a TIM, heat of the first electronic
component 500 is rapidly transferred into the first structure for
heat transfer 110 and then dissipated more rapidly, compared to an
example in which heat is transferred in the downward direction
only. Compared to the example that temperature at a certain region
such as hot spot rises excessively, because heat is dissipated
evenly across the entire region of the circuit board 100,
temperature variations of each component or element on the circuit
board 100 are decreased so that the reliability is increased. In
addition, since heat is rapidly dissipated across the entire region
of circuit board 100, the circuit board 100 itself functions as a
kind of heat radiation plate, so that it provides an effective
result of an enlarged heat radiation area.
[0099] In an example, the first circuit pattern P1 and the second
circuit pattern P2 are situated on surfaces of the core part 10,
and the first circuit pattern P1 and the second circuit pattern P2
are electrically connected to each other by means of a through via
TV that penetrates through the core part 10. In such an example,
the first circuit pattern P1 is connected to the third metal
pattern 133 by means of the fourth via V4. Also, the second circuit
pattern P2 is connected to the fourth metal pattern 142 by means of
the fifth via V5. Additionally, the third metal pattern 133 is
connected to the first electronic component 500 by means of solder
(S), and the fourth metal pattern 142 is connected to contact pad
810 of the additional board 800 by means of solder (S). Here, the
solder (S) acts as a binder between the various components.
Accordingly, routes for transmitting electrical signals between the
first electronic component 500 and the additional board 800 are
further secured.
[0100] The second core layer 12 is situated on one surface of the
first core layer 11. Also, the third core layer 13 is situated on
the other surface of the first core layer 11. In an example, at
least one of the second core layer 12 and the third core layer 13
is formed of insulating material such as PPG, which is a
combination of glass fibers and polypropylene. In another example,
the second core layer 12 and the third core layer 13 are formed of
a metal such as copper or invar. Here, invar, also known
generically as 64FeNi or FeNi36 is a nickel-iron alloy notable for
its uniquely low coefficient of thermal expansion. In still another
example, the first core layer 11 may be formed of invar, and the
second core layer 12 and the third core layer 13 may be formed of
copper. In an example such that at least one of the second core
layer 12 and the third core layer 13 is formed of conductive
material, since the first circuit pattern P1 or the second circuit
pattern P2 is formed on surfaces of the core part 10, it is
possible for signals to be transmitted via an unintended route.
Thus, a means for securing an insulation property are situated on
surfaces of the core part 10 in such an example.
[0101] In an example, the second electronic component 200 is
inserted in the second cavity C2 of the core part 10. Also, the
second electronic component 200 is connected to the seventh metal
pattern 134 by means of the sixth via V6 and the sixth metal
pattern 144 by means of the seventh via V7, respectively. In some
examples, the second electronic component 200 is a passive element
such as an inductor, a capacitor, or a similar passive electronic
component, and in other examples, the second electronic component
200 is an active element such as an integrated circuit, if desired
or required. In an example in which the second electronic component
200 is a capacitor, the terminal of the first electronic component
500 to be connected to the seventh metal pattern 134 is a power
terminal. That is, in such an example, the second electronic
component is embedded as a de-coupling capacitor to reduce the
power noise of the first electronic component 500.
[0102] In this example, it is better to provide a distance between
the capacitor and the first electronic component that is short in
order to increase a noise reduction effect. For this purpose, in an
example, at least a portion of the second electronic component 200
is situated below the first electronic component 500.
[0103] Although not illustrated, rather than a cavity that
penetrates the core part 10, a recess that is a depressed portion
of the core part 10 is formed. In such an example, the first
structure for heat transfer 110 or the second electronic component
200 is inserted into the recess.
[0104] Referring to the example of FIG. 1, the thickness of the
first structure for heat transfer 110 is selected to be larger than
a height from the lower surface of the second circuit pattern P2 to
the upper surface of the first circuit pattern P1. Furthermore, as
compared to the upper surface of the first circuit pattern P1, the
upper surface of the first structure for heat transfer 110 is
situated to be closer to the upper surface of the circuit board
100. Accordingly, the heat capacity of the first structure for heat
transfer 100 is increased so that the function of keeping heat is
improved. Furthermore, the distance between the first structure for
heat transfer 110 and the hot spot decreases. As a result, the time
that is used for heat to move from the hot spot to the first
structure for heat transfer 110 is shortened further.
[0105] In one example, the bottom surface of the first structure
for heat transfer 110 and the lower surface of the second circuit
pattern P2 are situated on the same horizontal plane. Even in this
example, the thickness of the first structure for heat transfer 110
is potentially selected to be larger than a height from the lower
surface of the second circuit pattern P2 to the upper surface of
the first circuit pattern P1. Accordingly, the heat capacity of the
first structure for heat transfer 100 is increased, and the
distance between the first structure for heat transfer 110 and the
hot spot decreases.
[0106] Although not shown, in another example, the upper surface of
the first structure for heat transfer 110 and the upper surface of
the first circuit pattern P1 are disposed on the same horizontal
plane. Even in this case, the thickness of the first structure for
heat transfer 110 is selected to be larger than a height from the
lower surface of the second circuit pattern P2 to the upper surface
of the first circuit pattern P1. Accordingly, the heat capacity of
the first structure for heat transfer 100 is increased. Although a
theoretical or an ideal geometrical relationship is described above
to help explain the examples, when this structure is applied to an
actual design made by a manufacturing process, variances possibly
arise during the manufacturing process. For example, in actual
manufacturing, both surfaces of the core part are not always
perfectly flat, or thicknesses of circuit patterns are changed
during the process of forming circuit patterns on the core part.
Therefore, when interpreting the scope of the present examples, the
actual process variances or the like are to be considered to ensure
that the process takes into account practical issues. In addition,
due to the trend of slimness of electronic devices and high density
of wiring patterns, a certain degree of warping potentially occurs
during the manufacturing process of a circuit board. When this
warping is intensified, it may cause a short circuit in wiring or a
crack. As a result, there have been many efforts to minimize the
warping. However, practically, it is not possible to eliminate the
warping completely, and even though a warping occurs but falls in a
certain range, a circuit board is still potentially sorted into
being a good product of acceptable quality. Thus, in the circuit
board according to an example, a warping that falls within a
certain range is allowed, and when understanding the description
about the thickness or location of the first structure for heat
transfer 110, the allowed range of warping is to be considered as
well.
[0107] Referring to the example of FIG. 2, although the second
upper insulation layer 122 is formed on the first upper insulation
layer 121, even in this case, it is to be understood that the heat
capacity of the first structure for heat transfer 110 is increased
and at the same time the heat dissipation speed is also increased
by making the height of the first via V1 or the second via V2 that
is interposed between the outer surface of the circuit board 100
and the first structure for heat transfer 110 smaller than that of
the via that connects the outer surface of the circuit board 100 to
the inner patterns P1', P2'. Although not shown, in an example the
upper surface of the first structure for heat transfer 110 is
covered by the first upper insulation layer. Also, the other
surface of the via by which one surface is contacted with the first
structure for heat transfer 110 is possibly in contact with the
circuit pattern that is disposed on the first upper insulation
layer. Further, the via is connected to the first electronic
component through another via that penetrates through the second
upper insulation layer and another circuit pattern that is situated
on the second insulation layer and the solder ball. That is, the
number of build-up layers to be formed on the first structure for
heat transfer 110 is possibly changed, if desired or required.
However, it is to be understood that the lager the thickness of the
first structure for heat transfer, the better the heat
capacity.
[0108] Referring to the example of FIG. 6, an insulation film 14 is
situated on the surfaces of core part 10. In an example, the first
core layer 11 through the third core layer 13 have a good
electrical conductivity as well as a good heat conductivity. Thus,
in case that the first circuit pattern P1 is situated on the
surface of the core part 10, it is required to prevent a current
flow though an unwanted path that is caused by the conductivity of
the core part 10. In such an example, the insulation film 14 is
formed on the core part by vapor deposition with parylene or
another appropriate material. During a time period in which a
through via hole for forming a through via TV is processed, the
insulation film is formed on an inside of the through via hole by
providing an insulating material on the surface of the core part
10. Accordingly, the insulation is secured between the through via
TV, the first and the second circuit patterns P1, P2 and the core
part 10.
[0109] In an example, a core via hole that penetrates the second
core layer 12 and the third core layer 13 so as to expose a portion
of the first core layer 11 is formed. In this example, the eighth
via that is formed by disposing a conductive material in the core
via hole is located to be in direct contact with the first core
layer 11. For example, the insulation film 14 is formed on the
surface of the core part 10 during a time period when the core via
hole is provided, the insulation film 14 is formed on the exposed
surface of the first core layer 11 so that the first core layer 11
is disposed to face the eighth via V8. The insulation film 14 is
interposed between the first core layer 11 and the eighth via V8.
In an example in which heat moves to the eighth via V8 that is
directly, or indirectly by means of the insulation film 14, in
contact with the first core layer 11, heat is be rapidly dissipated
in this direction, which is horizontal to the circuit board 100,
along the first core layer 11.
[0110] In an example, the second structure for heat transfer is
formed of graphite or graphene. Accordingly, heat that moves from a
heat source such as the first electronic component 500 or the like
to the first structure for heat transfer is rapidly dissipated in
the horizontal direction through the second structure for heat
transfer. Especially, as shown in FIGS. 1E through 1G and 2, in an
example in which the first structure for heat transfer 110 is
provided by arranging the first layer in the horizontal direction,
the heat radiation efficiency in the horizontal direction is
improved through the first core layer 11, as shown in FIG. 6.
[0111] As shown in the example of FIG. 6, a penetration hole 11c is
formed in the first core layer 11. Also, the second core layer 12
and the third core layer 13 are connected to each other in the
integrated fashion to firmly support the first core layer 11.
Accordingly, the inter-layer bonding power is reinforced even
though the first core layer 11 is formed of a graphite material or
a graphene material.
[0112] Referring to the example of FIG. 7, an example in which a
primer layer 111 is situated on the outer surface of the first core
layer 11' is depicted. That is, the inter-layer bonding power is
improved by situating the primer layer 111 on the outer surface of
the graphite sheet. Such a primer layer 111 improves not only the
inter-layer bonding power between graphite sheets, but also the
inter-layer bonding power between the first core layer 11' and the
second core layer 12 and between the first core layer 11' and the
third core layer 13.
[0113] In another example, referring to the example of FIG. 8, the
first core layer 11'' is provided by stacking unit structures 11-1,
11-2, 11-3, 11-4, that are formed by situating the primer layer 111
on the surface of a graphite layer, in the vertical direction. In
this example, a degree in the heat radiation of the first core
layer 11'' in the horizontal direction is minimized and at the same
time the de-lamination of the first core layer 11'' in the vertical
direction is relieved.
[0114] In still another example, referring to the example of FIG.
9, the first core layer 11''' is provided by stacking unit
structures 11-1, 11-2, 11-3, 11-4. Such structures are formed by
disposing the primer layer 111 on the surface of graphite, in the
horizontal direction. For example, the XY plane of graphite is
arranged in parallel to the vertical direction. In this case, the
heat radiation in the horizontal direction is decreased more or
less and does not always improve, but the heat radiation in the
vertical direction improves.
[0115] The first structure for heat transfer 110 of the circuit
board 100 according to an example includes an adhesion strength
reinforcing part for improving the adhesion strength to the
insulation part 120.
[0116] In an example where the surface of the first structure for
heat transfer 110 is in direct contact directly with the insulation
part 120, the first structure for heat transfer 110 and the
insulation part 120 are separated from each other during a reflow
process or solder pot process. This practice is referred to as
delamination. As a means for improving the adhesion strength to the
insulation part 120, the primer layer 111 is situated on the
surfaces of the first structure for heat transfer 110. In an
example, the primer layer 111 is formed of a primer that includes
isopropyl alcohol and an acryl-based silane agent.
[0117] Also, in another example, the primer layer 111 is formed of
MPS (3-(trimethoxysilyl)propylmethacrylate), and a silane-based
additive is added to the primer layer 111.
[0118] FIG. 10A shows a reflow test result that is performed during
a time period in which the primer layer 111 is situated on the
surfaces of the structure for heat transfer. FIG. 10B shows the
solder pot test result that is performed during a time period in
which the primer layer 111 is disposed on the surfaces of the
structure for heat transfer. FIG. 11A shows a reflow test result
that is performed during a time period in which the insulation part
120 is in direct contact with the structure for heat transfer. FIG.
11B shows the solder pot test result that is performed during a
time period in which the insulation part 120 is in direct contact
with the structure for heat transfer.
[0119] Referring to FIGS. 10A through 11B, in an example in which
the reflow process or the solder pot process is performed when
there is no primer layer 111, a delaminated space D is formed
between the structure for heat transfer and the insulation part
120. It is to be understood that the adhesion strength between the
structure for heat transfer and the insulation part 120 is improved
by situating the primer layer on the surfaces of the structure for
heat transfer. The structure for heat transfer is at least one of
the first structure for heat transfer 110 and the second structure
for heat transfer.
[0120] A surface processing, such as a black-oxidizing process, and
a roughing treatment process is performed on the surfaces of the
first structure for heat transfer 110. As a result, the adhesion
strength between the first structure for heat transfer 110 and the
insulation part 120 is improved.
[0121] However, if the surfaces of the first structure for heat
transfer 110 are processed as previously mentioned, a problem
potentially arises during the manufacturing process. For example,
the color of the first structure for heat transfer 110 potentially
changes due to the surface process. In such an example, faults
potentially occur frequently when an automatic equipment that
mounts the first structure for heat transfer 110 on a certain
position of the insulation part 120 identifies the first structure
for heat transfer 110.
[0122] Accordingly, in the circuit board 100 according to an
example, the de-lamination between the first structure for heat
transfer 110 and the insulation part 120 is decreased.
[0123] Referring to FIGS. 1A through 1F, in an example in which the
primer layer 111 is situated on the surfaces of the first structure
for heat transfer 110, the first via V1 or the second via V2
penetrate the primer layer 111 as well and are in direct contact
directly with the first structure for heat transfer 110. Thus, the
decrease in heat transfer performance due to the primer layer 111
is minimized. Here, the thickness of the primer layer 111 is
depicted in an exaggerated manner for a better understanding of the
primer layer 111. However, the primer layer 111 is formed to have
the thin film shape. Thus, the primer layer 111 in the actually
embodied circuit board is potentially substantially thinner than
that shown in the accompanying drawings. Thus, when understanding
the present examples, the exaggerated expression of the drawings is
to be considered as well. Especially, in FIG. 1A, the lower surface
of the primer layer 111 and the second circuit pattern P2 are
depicted to be situated along the same plane, and the bottom
surface of the first structure for heat transfer 110 except the
primer layer 111 is depicted to be situated somewhat higher than
the second circuit pattern P2. However, the thickness of the primer
layer 111 is very small compared to the thickness of the second
circuit pattern P2 or the thickness of the first structure for heat
transfer 110. Therefore, when understanding the positional
relationship between the first structure for heat transfer 110 and
the second circuit pattern P2, the thickness of the primer layer
111 is potentially ignored.
[0124] FIGS. 12 through 14A illustrate a method of manufacturing
the first structure for heat transfer according to an example.
[0125] Referring to FIGS. 12 through 14A, the method of
manufacturing a circuit board according to an example provides the
first structure for heat transfer 110 by forming the second layer
118-2 and the third layer 118-2 that are formed of a metallic
material on both surfaces of the first layer 119, wherein the first
layer 119 is formed of graphite or grapheme, as discussed
above.
[0126] For example, the first structure for heat transfer 110 is
mass-produced by using the first preliminary layer 119' through the
third preliminary layer 118-2', where the layers have certain
areas. For example, the first preliminary layer 119' through the
third preliminary layer 118-2' may be provided so as to have a
sheet shape that has relatively large area compared to its
thickness, and then by performing a dicing process, the first
structure for heat transfer 110 including the second layer 118-1,
the first layer 119, and the third layer 118-2 are mass-produced.
After the dicing process, the portion that corresponds to the first
preliminary layer 118-1' becomes the first layer 119, the portion
that corresponds to the second preliminary layer 118-1' becomes the
second layer 118-1, and the third preliminary layer 118-2' becomes
the third layer 118-2.
[0127] In FIGS. 12 through 14A, the first layer 119 through the
third layer 118-2 are illustrated to be provided by a lamination
process. However, as shown in FIG. 15, by performing a plating
process on the upper surface and the lower surface of the first
layer 119-1, the second layer 118-1 and the third layer 118-2 are
formed. By performing the plating process during a time period in
which the penetration hole 119H is formed in the first layer 119-1
to provide the metallic material, the second layer 118-1, the third
layer 118-2, and the metallic material that is filled in the
penetration hole 119H are formed in the integrated fashion. Thus
the bonding power between the first layer 119-1 and the second
layer 118-1 and between the first layer 119-1 and the third layer
118-2 is increased. Also, the inter-layer bonding power of graphite
or graphene that forms the first layer 119-1 is increased. After
further forming the third layer 119-2 on the outer surface of the
third layer 118-2, the third layer 118-3 is further situated
thereon.
[0128] Referring to FIG. 14B, after forming the second preliminary
layer 118-1', the first preliminary layer 119', and the third
preliminary layer 118-2', by adjusting the dicing line and
performing the dicing process, the first structure for heat
transfer 110-1 in which the first layer is arranged in the
horizontal direction is provided.
[0129] Unless indicated otherwise, a statement that a first layer
is "on" a second layer or a substrate is to be interpreted as
covering both a case where the first layer directly contacts the
second layer or the substrate, and a case where one or more other
layers are disposed between the first layer and the second layer or
the substrate.
[0130] Words describing relative spatial relationships, such as
"below", "beneath", "under", "lower", "bottom", "above", "over",
"upper", "top", "left", and "right", may be used to conveniently
describe spatial relationships of one device or elements with other
devices or elements. Such words are to be interpreted as
encompassing a device oriented as illustrated in the drawings, and
in other orientations in use or operation. For example, an example
in which a device includes a second layer disposed above a first
layer based on the orientation of the device illustrated in the
drawings also encompasses the device when the device is flipped
upside down in use or operation,
[0131] Expressions such as "first conductivity type" and "second
conductivity type" as used herein may refer to opposite
conductivity types such as N and P conductivity types, and examples
described herein using such expressions encompass complementary
examples as well. For example, an example in which a first
conductivity type is N and a second conductivity type is P
encompasses an example in which the first conductivity type is P
and the second conductivity type is N.
[0132] While this disclosure includes specific examples, it will be
apparent to one of ordinary skill in the art that various changes
in form and details may be made in these examples without departing
from the spirit and scope of the claims and their equivalents. The
examples described herein are to be considered in a descriptive
sense only, and not for purposes of limitation. Descriptions of
features or aspects in each example are to be considered as being
applicable to similar features or aspects in other examples.
Suitable results may be achieved if the described techniques are
performed in a different order, and/or if components in a described
system, architecture, device, or circuit are combined in a
different manner, and/or replaced or supplemented by other
components or their equivalents. Therefore, the scope of the
disclosure is defined not by the detailed description, but by the
claims and their equivalents, and all variations within the scope
of the claims and their equivalents are to be construed as being
included in the disclosure.
* * * * *