This application is based on and claims the benefit of priority from Taiwan Patent Application 102119669 filed on Jun. 3, 2013, which is incorporated herein by reference and assigned to the assignee hereof.
The present invention is related to a circuit board and a method of manufacturing the same and in particular, to a combined circuit board and a method of manufacturing the same.
In general, a conventional circuit board for carrying and electrically connecting a plurality of electronic components substantially comprises circuit layers and dielectric layers that are stacked alternately. Each of the circuit layers are defined and formed by performing a patterning process on a conductive layer. Each of the dielectric layers is disposed between adjacent ones of the circuit layers in order to space apart the adjacent circuit layers. In addition, each of the stacked circuit layers may be electrically connected to another by a conductive via. Furthermore, various electronic components (such as active components or passive components) can be disposed on a surface of the circuit board, and electrical signal propagation is achieved by means of an internal circuit of the circuit board.
Due to miniaturization of any of electronic products, the application of circuit boards rapidly increases; for example, circuit boards can be applied in clam type mobile phones and notebook computers. Accordingly, the development of combing a rigid circuit board and a flexible circuit board to form a combined circuit board is required.
The rigid circuit board 120 comprises a rigid dielectric layer 122 and a circuit layer 124. The rigid dielectric layer 122 is disposed on the surface 112a of the flexible dielectric layer 112 and the circuit layer 124 is disposed on the rigid dielectric layer 122 such that the rigid dielectric layer 122 is located between the flexible circuit board 110 and the circuit layer 124. The circuit layer 124 comprises a plurality of pads 124a. The conductive vias 140 are disposed in the rigid dielectric layer 122 and electrically connect the pads 124a and the golden finger contacts 114a. The rigid dielectric layer 130 is disposed on the surface 112b of the flexible dielectric layer 112 and corresponds in position to the rigid dielectric layer 122. Moreover, a chip (not shown) may be disposed on the rigid dielectric layer 122 and electrically connected to the pads 124a by means of wire bonding technology so as to be electrically connected to the golden finger contacts 114a.
The combined circuit board 100 has a thickness T1 in the vicinity of the golden finger contacts 114a and the thickness T1 can be 0.2 mm to meet the current industrial requirements. However, based on the limitation caused by the physical properties of the materials which are usually selected by the current industry for the rigid dielectric layers 122 and 130, a maximum thickness T2 of the combined circuit board 100, i.e., the thickness in the vicinity of the rigid dielectric layers 122 and 130, must be at least 0.3 mm. Hence, the conventional combined circuit board 100 cannot be further thinned.
Moreover, the process of manufacturing the conventional combined circuit board 100 is complicated. During the manufacturing process of the combined circuit board 100, the golden finger contacts 114a are preformed on the surface 112a of the flexible dielectric layer 112, and thus the flexible circuit board 110 is finished in advance. Afterward, the manufacturing process involves laminating a rigid substrate, the flexible circuit board 110 and the rigid dielectric layer 130, wherein the rigid substrate comprises the rigid dielectric layer 122 and a conductive layer disposed on the rigid dielectric layer 122 and usually a copper layer on a whole surface of the rigid dielectric layer 122. Afterward, the manufacturing process involves patterning the conductive layer to form the circuit layer 124 and performing drilling and electroplating steps to form the conductive vias 140. In doing so, the production of the conventional combined circuit board 100 is finalized. However, in the steps of lamination, patterning the conductive layer, and forming the conductive vias 140, the golden finger contacts 114a must be properly protected to be prevented from being damaged in the aforesaid steps. Moreover, when the golden finger contacts 114a are being formed, it is necessary to dispose the reinforcing plate 150 which corresponds in position to the golden finger contacts 114a to be formed. As a result, the process of manufacturing the conventional combined circuit board 100 is complicated.
The present invention provides a combined circuit board for which the process of manufacturing is relatively simple.
The present invention provides a combined circuit board of which the thickness can be thinner.
The present invention provides a method of manufacturing a combined circuit board, wherein the manufacturing process of the combined circuit board is relatively simple.
The present invention provides a method of manufacturing a combined circuit board, wherein the combined circuit board produced has a thinner thickness.
In an embodiment of the present invention, a combined circuit board comprising a flexible circuit board, a first rigid circuit board, at least one first conductive via and at least one second conductive via is provided. The flexible circuit board comprises a flexible dielectric layer and a first circuit layer disposed on the flexible dielectric layer. The first rigid circuit board comprises a first rigid dielectric layer and a second circuit layer. The first rigid dielectric layer is disposed on the flexible circuit board and comprises a first rigid dielectric portion and a second rigid dielectric portion spaced apart from the first rigid dielectric portion by a distance to expose a portion of the flexible circuit board. The second circuit layer comprises a main circuit and an out connection interface circuit. The main circuit is disposed on the first rigid dielectric portion, and the out connection interface circuit is disposed on the second rigid dielectric portion and comprises at least one contact. The at least one first conductive via is disposed in the second rigid dielectric portion and electrically connects the at least one contact and the first circuit layer. The at least one second conductive via is disposed in the first rigid dielectric portion and electrically connects the main circuit and the first circuit layer.
In an embodiment of the present invention, the first rigid dielectric layer comprises an epoxy resin and a glass fabric which meets the style 1017 of the IPC standard.
In an embodiment of the present invention, the flexible circuit board further comprises a third circuit layer disposed on the flexible dielectric layer. The first circuit layer and the third circuit layer are disposed on two opposite sides of the flexible dielectric layer, respectively. The combined circuit board further comprises a second rigid circuit board comprising a second rigid dielectric layer and a fourth circuit layer. The second rigid dielectric layer is disposed on the flexible circuit board, and the fourth circuit layer is disposed on the second rigid dielectric layer. The second rigid dielectric layer comprises a third rigid dielectric portion and a fourth rigid dielectric portion. The third rigid dielectric portion and the fourth rigid dielectric portion correspond in position to the first rigid dielectric portion and the second rigid dielectric portion, respectively. The second rigid circuit board and the first rigid circuit board are disposed on two opposite sides of the flexible circuit board, respectively.
In an embodiment of the present invention, the first rigid dielectric layer comprises an epoxy resin and a glass fabric which meets the style 1017 of the IPC standard, and the second rigid dielectric layer comprises an epoxy resin and a glass fabric which meets the style 1017 of the IPC standard. The combined circuit board has a maximum thickness which is not larger than 0.2 mm.
In an embodiment of the present invention, the at least one contact is a golden finger contact.
In an embodiment of the present invention, a method of manufacturing a combined circuit board comprising the following steps is provided. First, a flexible circuit board comprising a flexible dielectric layer and a first circuit layer disposed on the flexible dielectric layer is provided. Next, a first rigid substrate comprising a first rigid dielectric layer and a first conductive layer disposed on the first rigid dielectric layer is provided. Next, the flexible circuit board and the first rigid substrate is laminated such that the first rigid dielectric layer is located between the first conductive layer and the flexible circuit board. Next, the first conductive layer is patterned to form a second circuit layer, wherein the first rigid dielectric layer and the second circuit layer together form a first rigid circuit board.
Next, a plurality of conductive vias in the first rigid dielectric layer are formed, wherein each of the conductive vias electrically connects the second circuit layer and the first circuit layer. Afterwards, a portion of the first rigid circuit board is removed to expose a portion of the flexible circuit board. The first rigid dielectric layer is divided into a first rigid dielectric portion and a second rigid dielectric portion spaced apart from the first rigid dielectric portion by a distance. The second circuit layer is divided into a main circuit and an out connection interface circuit. The conductive vias are divided into at least one first conductive via and at least one second conductive via. The main circuit is disposed on the first rigid dielectric portion, and the out connection interface circuit is disposed on the second rigid dielectric portion and comprises at least one contact. The at least one first conductive via is disposed in the second rigid dielectric portion and electrically connects the at least one contact and the first circuit layer. The at least one second conductive via is disposed in the first rigid dielectric portion and electrically connects the main circuit and the first circuit layer.
In an embodiment of the present invention, the first rigid dielectric layer comprises an epoxy resin and a glass fabric which meets the style 1017 of the IPC standard.
In an embodiment of the present invention, the flexible circuit board further comprises a third circuit layer disposed on the flexible dielectric layer. The first circuit layer and the third circuit layer are disposed on two opposite sides of the flexible dielectric layer, respectively. The method of manufacturing the combined circuit further comprises the following steps. A second rigid substrate comprising a second rigid dielectric layer and a second conductive layer disposed on the second rigid dielectric layer is provided. Next, the flexible circuit board and the second rigid substrate is laminated such that the second rigid dielectric layer is located between the second conductive layer and the flexible circuit board. The second rigid substrate and the first rigid substrate are disposed on two opposite sides of the flexible circuit board, respectively. Next, the second conductive layer is patterned to form a fourth circuit layer. The second rigid dielectric layer and the fourth circuit layer together form a second rigid circuit board. Next, a portion of the second rigid circuit board is removed to expose another portion of the flexible circuit board. The second rigid dielectric layer is divided into a third rigid dielectric portion and a fourth rigid dielectric portion. The third rigid dielectric portion and the fourth rigid dielectric portion correspond in position to the first rigid dielectric portion and the second rigid dielectric portion, respectively.
In an embodiment of the present invention, the first rigid dielectric layer comprises an epoxy resin and a glass fabric which meets the style 1017 of the IPC standard, and the second rigid dielectric layer comprises an epoxy resin and a glass fabric which meets the style 1017 of the IPC standard. The combined circuit board has a maximum thickness which is not larger than 0.2 mm.
In an embodiment of the present invention, the at least one contact is a golden finger contact.
During the manufacturing process of the combined circuit board of the embodiment of the present invention, the contact of the rigid circuit board comprising the out connection interface circuit is formed on the rigid dielectric layer of the rigid circuit board at the step of patterning the conductive layer. In this embodiment of the present invention, the contact is not formed yet during the laminating step and is being formed during the patterning step. Hence, compared to the conventional art, the contact of the embodiment of the present invention does not require additional protection during the two steps and the reinforcing plate is not required while the contact is being formed. Accordingly, the method of manufacturing the combined circuit board of the embodiment of the present invention is relatively simple. In addition, because the rigid dielectric layer comprises the epoxy resin and the glass fabric which meets the style 1017 of the IPC standard, compared to the conventional art, the thickness of the rigid dielectric layer can be reduced and the structural strength requirements for the rigid dielectric layer can be still meet such that the maximum thickness of the combined circuit board of this embodiment of the present invention can be effectively reduced and therefore, the combined circuit board can be thinner.
The rigid circuit boards 220 and 230 are disposed on two opposite sides of the flexible circuit board 210, respectively. The rigid circuit board 220 comprises a rigid dielectric layer 222 and a circuit layer 224. The rigid dielectric layer 222 is disposed on the flexible circuit board 210 and the circuit layer 224 is disposed on the rigid dielectric layer 222 such that the rigid dielectric layer 222 is disposed between the flexible circuit board 210 and the circuit layer 224. The rigid dielectric layer 222 comprises two rigid dielectric portions 222a and 222b. The rigid dielectric portion 222a and the rigid dielectric portion 222b are spaced apart from each other by a distance D1 such that a portion of the flexible circuit board 210 is exposed. The circuit layer 224 comprises a main circuit 224a and an out connection interface circuit 224b. The main circuit 224a is disposed on the rigid dielectric portion 222a. The main circuit 224a comprises at least one pad P1 and a plurality of the pads P1 are schematically shown in
A plurality of conductive vias 240 are disposed in the rigid dielectric portion 222b (only one conductive via 240 is schematically shown in
In this embodiment, the rigid circuit board 230 comprises a rigid dielectric layer 232 and a circuit layer 234. The rigid dielectric layer 232 is disposed on the flexible circuit board 210 and the circuit layer 234 is disposed on the rigid dielectric layer 232 such that the rigid dielectric layer 232 is disposed between the flexible circuit board 210 and the circuit layer 234. The rigid dielectric layer 232 comprises two rigid dielectric portions 232a and 232b. The rigid dielectric portions 232a and 232b of the rigid dielectric layer 232 correspond in position to the rigid dielectric portions 222a and 222b of the rigid dielectric layer 222, respectively.
Each of the rigid dielectric layers 222 and 232 is made of an epoxy resin and a glass fabric which meets the style 1017 of the IPC standard. That is to say, each of the rigid dielectric layers 222 and 232 comprises the epoxy resin and a plurality of fiberglass included in the glass fabric which meets the style 1017 of the IPC standard. The rigidity of each of the rigid dielectric layers 222 and 232 comprising the fiberglass and resin is relatively high. Moreover, the glass fabric which meets the style 1017 of the IPC standard has a thickness of about 10 μm and contains the fiberglass each of which has a diameter of about 4 μm. Because each of the rigid dielectric layers 222 and 232 comprises the epoxy resin and the glass fabric which meets the style 1017 of the IPC standard, compared to the conventional art, the thickness of each of the rigid dielectric layers 222 and 232 can be reduced and the structural strength requirements for them can be still meet such that the maximum thickness T3 of the combined circuit board 200 of this embodiment can be effectively reduced to 0.2 mm or even less and therefore, the combined circuit board 200 can be thinner.
In another embodiment, the rigid circuit boards 230 and the circuit layer 216 of the flexible circuit board 210 can be omitted in the combined circuit board 200, but the above mentioned is not depicted in any drawing.
A method of manufacturing the combined circuit board 200 according to this embodiment of the present invention is described below.
Afterward, referring to
Afterward, referring to
After the step depicted in
In this embodiment, the contacts C1 of the out connection interface circuit 224b of the circuit layer 224 are formed on the rigid dielectric layer 222 of the rigid circuit board 220 at the step of patterning the conductive layer 224.′ In this embodiment, the contacts C1 are not formed yet during the laminating step and are being formed during the patterning step. Hence, compared to the conventional art, the contacts C1 of the present embodiment do not require additional protection during the two steps and the reinforcing plate 150 (see
Based on the above mentioned, the combined circuit board has one of the following advantages or another advantage.
During the manufacturing process of the combined circuit board of the embodiment of the present invention, the contact of the rigid circuit board comprising the out connection interface circuit is formed on the rigid dielectric layer of the rigid circuit board at the step of patterning the conductive layer. In this embodiment of the present invention, the contact is not formed yet during the laminating step and is being formed during the patterning step. Hence, compared to the conventional art, the contact of the embodiment of the present invention does not require additional protection during the two steps and the reinforcing plate is not required while the contact is being formed. Accordingly, the method of manufacturing the combined circuit board of the embodiment of the present invention is relatively simple.
Because the rigid dielectric layer comprises the epoxy resin and the glass fabric which meets the style 1017 of the IPC standard, compared to the conventional art, the thickness of the rigid dielectric layer can be reduced and the structural strength requirements for the rigid dielectric layer can be still meet such that the maximum thickness of the combined circuit board of this embodiment of the present invention can be effectively reduced and therefore, the combined circuit board can be thinner.
Number | Date | Country | Kind |
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102119669 | Jun 2013 | TW | national |