TWI477212B - Rigid and flexible composite circuit board and manufacturing metodh thereof - Google Patents

Description

Soft and hard composite circuit board and manufacturing method thereof

The present invention relates to a circuit board, and more particularly to a method of manufacturing a soft and hard composite circuit board.

The circuit board can be divided into a hard circuit board and a flexible circuit board according to the flexibility of the insulation layer. However, when an electronic component is to be soldered to a flexible circuit board, the flexible circuit board does not provide sufficient structural strength. In the case where the same electronic components are required to be soldered, although the rigid wiring board provides structural strength, the flexibility of the rigid wiring board is poor, thereby limiting the application of the rigid wiring board.

The soft and hard composite circuit board is a circuit board which is composed of a flexible circuit board and a rigid circuit board, and has both the flexibility of the flexible circuit board and the strength of the rigid circuit board. It is known that the fabrication of a soft and hard composite circuit board must first reserve a contact with the flexible circuit board on the rigid circuit board, so the position of the contact will affect and limit the circuit layout on the rigid circuit board. Moreover, in general, the contact position on the rigid circuit board is generally located in the peripheral area of the rigid circuit board, and the purpose is to facilitate subsequent electrical connection with the flexible circuit board. However, this design will increase the thickness and volume of the soft and hard composite circuit board structure after the subsequent assembly, which cannot meet the trend of light, thin, short and small for electronic products.

The invention provides a soft and hard composite circuit board and a manufacturing method thereof, which can Effectively reduce overall size to meet light, thin, short, and small design trends.

The present invention provides a method of manufacturing a soft and hard composite wiring board comprising the following steps. Provide a rigid circuit board. An insulating layer and a flexible circuit board are provided, wherein the insulating layer is disposed on the flexible circuit board. The insulating layer has an opening and the opening exposes a portion of the flexible circuit board. The rigid circuit board, the insulating layer and the flexible circuit board are pressed together to connect the insulating layer between the rigid circuit board and the flexible circuit board. A closed area is defined between the opening of the insulating layer, the rigid wiring board and the flexible wiring board. Forming a plurality of first conductive vias in the insulating layer, wherein one end of each of the first conductive vias is connected to the flexible circuit board. The other end of each of the first conductive vias is connected to the rigid wiring board. With the enclosed area as a positioning reference point, a portion of the rigid circuit board above the opening is removed to expose portions of the flexible circuit board.

In an embodiment of the invention, the rigid circuit board includes a plurality of conductive layers, a plurality of dielectric layers, and a plurality of second conductive vias. The conductive layer and the dielectric layer are alternately stacked with each other, and the second conductive via is located between the adjacent two conductive layers.

In an embodiment of the invention, the flexible circuit board comprises a base layer and a circuit layer on the base layer.

In an embodiment of the invention, the method for manufacturing the soft-hard composite circuit board described above further includes the following steps. Before removing a portion of the rigid wiring board located above the opening, a first solder resist layer is formed on the rigid wiring board, wherein the first solder resist layer is located on a surface of the rigid wiring board relatively away from the flexible wiring board.

In an embodiment of the invention, the above-mentioned system of soft and hard composite circuit boards The manufacturing method further includes the following steps. A cover layer is press-bonded to the flexible circuit board before removing the portion of the rigid circuit board above the opening, wherein the cover layer is on a surface of the flexible circuit board that is relatively far from the rigid circuit board.

In an embodiment of the invention, the method for manufacturing the soft-hard composite circuit board described above further includes the following steps. After pressing the cover layer on the flexible circuit board, a second solder resist layer is formed on the flexible circuit board and the cover layer, wherein the second solder resist layer exposes a portion of the cover layer.

In an embodiment of the invention, the step of removing the portion of the rigid line above the opening comprises the steps described below. Performing a laser cutting on the rigid circuit board to form at least two recesses in the rigid circuit board, wherein the recess exposes a portion of a conductive layer of the hard circuit board adjacent to the outermost layer of the insulating layer, and the conductive layer is located in the closed area Above. A portion of the conductive layer exposed by the recess is subjected to an etching step to remove portions of the conductive layer.

The invention provides a soft and hard composite circuit board comprising a rigid circuit board, a flexible circuit board, an insulating layer and a plurality of first conductive vias. The rigid circuit board has a first opening. The flexible circuit board is disposed on the rigid circuit board, and the first opening exposes a portion of the flexible circuit board. The insulating layer is disposed between the rigid circuit board and the flexible circuit board, and the insulating layer has a second opening. The second opening communicates with the first opening and exposes a portion of the flexible circuit board. The first conductive via penetrates the insulating layer and connects the rigid circuit board and the flexible circuit board.

In an embodiment of the invention, the rigid circuit board includes a plurality of conductive layers, a plurality of dielectric layers, and a plurality of second conductive vias. The conductive layer and the dielectric layer are alternately stacked with each other, and the second conductive via is located adjacent to the two conductive layers between.

In an embodiment of the invention, the flexible circuit board comprises a base layer and a circuit layer on the base layer.

In an embodiment of the invention, the soft and hard composite circuit board further includes a first solder resist layer. The first solder resist layer is disposed on the rigid circuit board, wherein the first solder resist layer is located on a surface of the rigid circuit board that is relatively far from the flexible circuit board.

In an embodiment of the invention, the soft and hard composite circuit board further includes a cover layer. The cover layer is disposed on the flexible circuit board, wherein the cover layer is located on a surface of the flexible circuit board relatively far from the rigid circuit board.

In an embodiment of the invention, the soft and hard composite circuit board further includes a second solder resist layer. The second solder resist layer is disposed on the cover layer and the flexible circuit board, wherein the second solder resist layer exposes a portion of the cover layer.

Based on the above, the method for manufacturing the soft and hard composite circuit board of the present invention is to directly press the flexible circuit board onto the rigid wiring board to serve as the outer conductive layer of the rigid wiring board, thereby saving process time and reducing alignment difficulty. Further, by the method for manufacturing a soft and hard composite wiring board of the present invention, a soft and hard composite wiring board having a relatively thin thickness can be manufactured.

The above described features and advantages of the present invention will be more apparent from the following description.

1 to 9 are schematic cross-sectional views showing a method of fabricating a soft and hard composite circuit board according to an embodiment of the present invention. Please refer to FIG. 1 first, the embodiment The manufacturing method of the soft and hard composite circuit board 100 includes the following steps. First, a rigid wiring board 110 is provided. The rigid wiring board 110 includes a plurality of conductive layers 112, a plurality of dielectric layers 114, and a plurality of conductive vias 116. The conductive layer 112 and the dielectric layer 114 are alternately stacked with each other, and the conductive vias 116 are located between the adjacent conductive layers 112. In other words, the conductive vias 116 are electrically connected to the adjacent conductive layer 112 through the dielectric layer 114. In the present embodiment, the structure of the rigid wiring board 110 can be regarded as a build-up line structure, and the present invention does not limit the stacked form of the build-up line structure and the number of stacked layers.

Next, referring to FIG. 2, an insulating layer 120 and a flexible wiring board 130 are provided. The insulating layer 120 is disposed on the flexible wiring board 130. The insulating layer 120 has an opening 120s in which the opening 120s exposes a portion 136 of the flexible wiring board 130.

In the present embodiment, the flexible circuit board 130 includes a base layer 132 and a circuit layer 134, wherein the circuit layer 134 is disposed on the base layer 132. The base layer 132 is located between the circuit layer 134 and the insulating layer 120, and the opening 120s of the insulating layer 120 exposes a portion of the base layer 132 of the flexible wiring board 130. The material of the base layer 132 is, for example, Polyimide (PI), Polyethylene Terephthalate (PET) or other suitable materials. Specifically, the opening 120s is formed, for example, by removing a portion of the insulating layer 120 by routing or die.

Next, referring to FIG. 3, the flexible circuit board 130, the insulating layer 120, and the rigid wiring board 110 are pressed to connect the insulating layer 120 between the flexible wiring board 130 and the rigid wiring board 110. At this time, the opening 120s of the insulating layer 120, the rigid wiring board 110, and the flexible wiring board 130 can be defined. A closed area 150.

Next, referring to FIG. 4, a conductive via 140 is formed in the insulating layer 120 and the flexible wiring board 130. The conductive vias 140 extend through the insulating layer 120 to electrically connect the rigid wiring board 110 and the flexible wiring board 130. For example, an opening may be formed in the insulating layer 120 and the flexible wiring layer 130 by using a laser process, and then a conductive material is filled in the opening to form the conductive via 140.

The flexible wiring board 130 of the present embodiment is directly pressed onto the rigid wiring board 110 through the insulating layer 120 to serve as an outer layer conducting layer of the rigid wiring board 110, so that the processing time can be shortened. In addition, since the contacts connected to the flexible circuit board 130 are not separately designed on the rigid circuit board 100, the circuit layout of the rigid circuit board 100 can have better design flexibility, and the rigid circuit board 110 and the softness can also be reduced. The alignment problem between the circuit boards 130. Accordingly, the soft and hard composite circuit board 100 of the present embodiment can have a better process yield.

Next, referring to FIG. 5, a first solder resist layer 160 may be selectively formed on the rigid wiring board 110. The first solder resist layer 160 is located on a surface 110a of the rigid wiring board 110 relatively away from the flexible wiring board 130. The function of the first solder resist layer 160 is, for example, to protect the wiring structure (such as the conductive layer 112) on the rigid wiring board 110 from being affected during soldering, and to avoid oxidation of the circuit structure, and to reduce subsequent electronic components ( Not shown) is soldered to an incorrect location.

Next, referring to FIG. 6, a cover layer 170 may be selectively pressed on the flexible circuit board 130. The cover layer 170 is located on a surface 130a of the flexible circuit board 130 relatively far from the rigid circuit board 110, and is covered. The cover layer 170 is disposed corresponding to the portion 136 of the flexible circuit board 130. The material of the cover layer 170 is, for example, polyethylene terephthalate (PET) or polyimide (PI). The cover layer 170 is, for example, an insulating protective layer which is provided with insulation, solder resist, or the like to protect the flexible wiring board 130. It should be noted that the present invention does not limit the order in which the first solder resist layer 160 and the cap layer 170 are formed. In other words, the first solder resist layer 160 may be formed after the cap layer 170 is formed.

Next, referring to FIG. 7 , after the cap layer 170 is pressed onto the flexible circuit board 130 , a second solder resist layer 180 may be selectively formed on the flexible circuit board 130 and the cap layer 170 . The second solder mask 180 exposes a portion 172 of the cover layer 170. The function of the second solder resist layer 180 is, for example, to protect the base layer 132 on the flexible wiring board 130.

Next, referring to FIG. 8, a hard cut of the rigid wiring board 110 is performed to form at least two recesses 140t in the rigid wiring board 110. In particular, the enclosed area 150 can further serve as a positioning reference point for laser cutting. After the laser cutting, the recess 140t exposes a portion 112z1 of a conductive layer 112z of the outermost layer of the rigid wiring board 110. The conductive layer 112z is the conductive layer 112 of the rigid wiring board 110 that is closest to the flexible wiring board 130. The conductive layer 112z is located above the enclosed region 150, and the portion 112z1 of the conductive layer 112z is located between the recess 140t and the enclosed region 150.

Next, referring to FIG. 9, after an etching step of the portion 112z1 of the conductive layer 112z exposed by the recess 140t, the portion 112z1 of the conductive layer 112z is removed. In detail, the groove 140t is used as a positioning reference point, and the portion 118 of the rigid wiring board 110 located above the opening 120s is removed. An opening 110s can be formed. At this time, the opening 110s in the rigid wiring board 110 communicates with the opening 120s located in the insulating layer 120 and exposes the portion 136 of the flexible wiring board 130.

Structurally, referring again to FIG. 9, the surface of the exposed portion 136 of the flexible wiring board 130 can serve as a surface for carrying the electronic component layer, and the electronic component layer can pass through the wiring layer 134 in the flexible wiring board 130 and The conductive vias 140 are electrically connected to the rigid wiring board 110. In other words, the electronic component layer can be buried in the soft and hard composite wiring board 100, so that an electronic component having a slim, short, and small shape can be obtained. In addition, since the flexible circuit board 130 of the present embodiment is directly pressed onto the rigid wiring board 110 through the insulating layer 120 having the opening 120s to serve as the outer conductive layer of the rigid wiring board 110, the thickness of the soft and hard composite wiring board 100 can be Drastically reduced.

FIG. 10 is a cross-sectional view showing a soft and hard composite circuit board according to another embodiment of the present invention. The soft and hard composite circuit board 100a of FIG. 10 is substantially similar to the soft and hard composite circuit board 100 of FIG. 9, except that the soft and hard composite wiring board 100a further includes a conductive via 190. The conductive via 190 penetrates each of the conductive layers 112 of the rigid wiring board 110, and the conductive vias 190 also penetrate the insulating layer 120 and the flexible wiring board 130. Accordingly, the conductive vias 190 can further ensure electrical connection between the conductive layers 112 of the rigid wiring board 110 and ensure electrical connection between the rigid wiring board 110 and the flexible wiring board 130.

In summary, the soft and hard composite circuit board of the present invention is formed by pre-forming an opening in the insulating layer, and defining a closed region through the opening, the rigid wiring board, and the flexible wiring board. The above enclosed area will be available as Remove the positioning datum point of the part of the hard board. In addition, the soft and hard composite circuit board of the present invention is manufactured by directly bonding a flexible circuit board through an insulating laminate having an opening to a rigid wiring board to serve as an outer conductive layer of the rigid wiring board, thereby saving process time and reducing the pair. It is difficult to manufacture, and it is also possible to manufacture soft and hard composite circuit boards with thin thickness.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Soft and hard composite panels

110‧‧‧hard circuit board

110a‧‧‧ surface

110s‧‧‧ openings

112‧‧‧ Conductive layer

112z‧‧‧ outermost conductive layer

Section 112z1‧‧‧

114‧‧‧Dielectric layer

116‧‧‧ Conductive through hole

Section 118‧‧‧

120‧‧‧Insulation

120s‧‧‧ openings

130‧‧‧Soft circuit board

130a‧‧‧ surface

132‧‧‧ basal layer

134‧‧‧circuit layer

140‧‧‧ Conductive through hole

140t‧‧‧ groove

150‧‧‧closed area

160‧‧‧First solder mask

170‧‧‧ Coverage

Section 172‧‧‧

180‧‧‧Second solder mask

190‧‧‧ conductive vias

1 to 9 are schematic cross-sectional views showing a method of fabricating a soft and hard composite circuit board according to an embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a soft and hard composite circuit board according to another embodiment of the present invention.

100‧‧‧Soft and hard composite panels

110‧‧‧hard circuit board

110a‧‧‧ surface

110s‧‧‧ openings

112‧‧‧ Conductive layer

114‧‧‧Dielectric layer

116‧‧‧ Conductive through hole

120‧‧‧Insulation

120s‧‧‧ openings

130‧‧‧Soft circuit board

130a‧‧‧ surface

132‧‧‧ basal layer

134‧‧‧circuit layer

140‧‧‧ Conductive through hole

160‧‧‧First solder mask

170‧‧‧ Coverage

Section 172‧‧‧

180‧‧‧Second solder mask

Claims (9)

A method for manufacturing a soft and hard composite circuit board, comprising: providing a rigid circuit board; providing an insulating layer and a flexible circuit board, wherein the insulating layer is disposed on the flexible circuit board, and the insulating layer has an opening, and the insulating layer has an opening Opening a portion of the flexible circuit board; pressing the flexible circuit board, the insulating layer, and the rigid circuit board to connect the insulating layer between the rigid circuit board and the flexible circuit board, wherein the insulating layer A closed area is defined between the opening, the rigid circuit board and the flexible circuit board; a plurality of first conductive vias are formed in the insulating layer, wherein one end of each of the first conductive vias is connected to the flexible circuit board, And the other end of each of the first conductive vias is connected to the rigid circuit board to press a cover layer on the flexible circuit board, wherein the cover layer is located on a surface of the flexible circuit board that is relatively far away from the rigid circuit board; a second solder resist layer on the flexible circuit board and the cover layer, wherein the second solder resist layer exposes a portion of the cover layer, and a portion of the second solder resist layer is in direct contact with the Of the circuit board; and to the portion of the closed area is a positioning reference point, removing a portion of the rigid circuit board is located above the opening of this, to expose the flexible printed circuit board. The method for manufacturing a soft and hard composite circuit board according to claim 1, wherein the rigid circuit board comprises a plurality of conductive layers, a plurality of dielectric layers, and a plurality of second conductive vias, and the conductive layer Some dielectric layers Stacked alternately, and the second conductive vias are located between two adjacent conductive layers. The method of manufacturing a soft and hard composite circuit board according to claim 1, wherein the flexible circuit board comprises a base layer and a circuit layer on the base layer. The method for manufacturing a soft and hard composite circuit board according to claim 1, further comprising: forming a first solder resist layer on the hard line before removing the portion of the rigid circuit board above the opening The board, wherein the first solder resist layer is located on a surface of the rigid circuit board that is relatively far from the flexible circuit board. The method of manufacturing a soft and hard composite circuit board according to claim 1, wherein the step of removing the portion of the hard line above the opening comprises: performing a laser cutting on the rigid board to Forming at least two grooves in the rigid circuit board, wherein the grooves expose a portion of a conductive layer adjacent to the outermost layer of the insulating layer, and the conductive layer is located above the closed region; The portion of the conductive layer exposed by the recesses is subjected to an etching step to remove the portion of the conductive layer. A soft and hard composite circuit board comprising: a rigid circuit board having a first opening; a flexible circuit board disposed on the rigid circuit board; and the first opening exposing a portion of the flexible circuit board; An insulating layer disposed between the rigid circuit board and the flexible circuit board, wherein the insulating layer has a second opening, the second opening communicates with the first opening and exposes a portion of the flexible circuit board Disposed on the flexible circuit board, wherein the cover layer is located on a surface of the flexible circuit board that is relatively far away from the rigid circuit board; a second solder resist layer is disposed on the cover layer and the flexible circuit board, wherein the cover layer The second solder resist layer exposes a portion of the cover layer, and a portion of the second solder resist layer directly contacts the flexible circuit board; and a plurality of first conductive vias extending through the insulating layer and connecting the rigid wiring board and the Flexible circuit board. The soft and hard composite circuit board of claim 6, wherein the rigid circuit board comprises a plurality of conductive layers, a plurality of dielectric layers, and a plurality of second conductive vias, the conductive layers and the dielectric layers The layers are alternately stacked with each other, and the second conductive vias are located between the adjacent two of the conductive layers. The soft and hard composite circuit board of claim 6, wherein the flexible circuit board comprises a base layer and a circuit layer on the base layer. The soft and hard composite circuit board of claim 6, further comprising a first solder resist layer disposed on the rigid circuit board, wherein the first solder resist layer is located on the rigid circuit board relatively far from the flexible circuit On one surface of the board.