TWI388262B - Fabrication method of rigid-flex circuit board - Google Patents

Description

Soft and hard bonding board manufacturing method

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

Simply put, the Rigid-Flex Circuit Board is a circuit board that combines a soft board and a hard board into the same product, and has the flexibility of a flexible circuit board and the strength of a rigid circuit board. Early applications in the military, medical, industrial equipment and other fields, in recent years, began to be used in mobile phones and consumer electronics (digital cameras, digital cameras, etc.) and other end products. In the application of the soft and hard combination board in the mobile phone, the image module, the button module and the RF module of the folding type mobile phone are commonly used.

The advantages of using a hard and soft combination board for the mobile phone include making the parts of the mobile phone easier to integrate and increasing the reliability of the signal transmission. The combination of the soft and hard board can replace the original combination of the two connectors and the soft board to increase the durability of the mobile phone folding point and the reliability of long-term use.

The application of soft and hard bonding boards has gradually expanded to other fields, such as flash memory, DRAM Module, and TFT-LCD Module. However, in the general soft and hard board bonding process, the soft board is usually in the middle layer of the two hard boards, the two ends of the soft board are sandwiched by two hard boards, and the middle section of the soft board is bendable. The area is used as a bridge between the two hard boards. However, the length of the soft and hard bonding board is limited by the processing area of the printed circuit board production equipment, so that the board length of the soft and hard bonding board cannot be extended beyond the processing area, especially for the manufacturing method of the long strip type soft and hard bonding board. Breaking through the size barrier, in addition to the appearance of the soft and hard board, may also result in a reduction in the utilization of the hard board. Therefore, how to improve the existing production methods and the convenience of subsequent assembly are all problems that the industry needs to solve.

The invention provides a method for manufacturing a soft and hard bonding board, which can break through the obstacles in size, and can extend the hard board unit in one direction by folding the soft board, thereby improving the existing production mode and the convenience of subsequent assembly. Sex.

The invention provides a method for manufacturing a soft and hard bonding board. First, a hard board having a first circuit layer is provided, and a plurality of soft boards having a second circuit layer, the hard board including a predetermined removal area and a plurality of hard board units. Next, a plurality of cutting lines that are intended to expose the area of the flexible board are cut between the hard board units and the predetermined removal area. These soft sheets are bonded to the hard board using a glue layer. Thereafter, a plurality of via holes are formed in the hard board and the soft boards to electrically conduct the first circuit layer on the hard board and the second circuit layer on the flexible board. The predetermined removal areas are respectively broken along the cutting lines on the hard plate to expose the respective flexible sheets and shape the hard board units. Each of the flexible sheets is folded in half along the respective plurality of folding lines so that the hard board units are arranged to extend in one direction.

In an embodiment of the present invention, the folding step of the soft board comprises sequentially folding a soft board along a vertical folding line, and folding the soft board along a horizontal folding line to overlap a soft area of the soft board. On another part of the board.

The invention provides a method for manufacturing a soft and hard bonding board, comprising: providing a two-hard board unit and a soft board, wherein the soft board is joined between the two hard board units by a glue layer, so that the soft and hard bonding board has a first length And folding a plurality of fold lines along the flexible board such that the soft and hard bond plates have a second length along the first length, the second length being greater than the first length.

In an embodiment of the invention, the hard board is a rigid circuit board having a double-sided circuit layer.

In an embodiment of the invention, the soft board is a flexible circuit board having a double-sided circuit layer.

In an embodiment of the invention, after the bonding of the soft and hard bonding board, the method further comprises forming a plurality of via holes in the soft board and the second hard board unit.

In an embodiment of the invention, the folding step of the soft board comprises: folding a pair of vertical folding lines; and folding along a horizontal folding line, and overlapping a part of the soft board with another part of the soft board. on.

In an embodiment of the invention, the folding step of the soft board comprises: folding in a horizontal fold line; and folding along a pair of corner fold lines, so that a part of the soft board overlaps another part of the soft board On the area.

Based on the above, the manufacturing method of the soft and hard bonding board of the present invention overcomes the obstacle that cannot be broken in size, and can be combined into an extended soft and hard bonding board, which improves the defects of the existing production mode and improves the convenience in subsequent assembly.

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

FIG. 1 is a schematic view showing a soft and hard bonding board in an unfolded state according to an embodiment of the present invention. 2A to 2B are schematic cross-sectional views of the soft and hard bonding board taken along the line I-I perpendicular to the folding line of Fig. 1.

Referring to FIG. 1 and FIG. 2A , the soft and hard bonding board 100 includes a hard board 110 , a plurality of soft boards 120 , and a bonding layer 130 connected between the hard board 110 and the soft board 120 . The hard board 110 has a predetermined removal area 110A and a plurality of hard board units 111 to 118, and a plurality of cutting lines 110B may be formed between the respective hard board units 111 to 118 and the predetermined removal area 110A. The cutting line 110B is formed, for example, by a V-cutting machine or by laser cutting, but is not completely cut, and the depth can be controlled to 8 to 16 mils. The glue layer 130 may be first stamped or cut with a laser to remove the region 132 corresponding to the flexing position of each of the flexible sheets 120 to form a patterned glue layer 130. Each of the hard plates 110 is further integrated into the polyimide film 122 of the soft board 120 by the bonding layer 130.

The hard board 110 has a first wiring layer 110D, and each soft board 120 has a second wiring layer 124. After the hard plate 110 and the soft board 120 are pressed together, a plurality of via holes 140 may be formed between the hard board 110 and each of the soft boards 120. The via hole 140 is generally formed by drilling to form a conductive layer on the hole wall to electrically conduct the first circuit layer 110D and the second circuit layer 124. On the hard board 110 or the soft board 120, the outer circuit can be formed by a general circuit board layering method.

Thereafter, in the step of breaking the predetermined removal area, the respective hard plate units 111 to 118 are first formed, and the molding manner thereof may be a method commonly used for a general printed circuit board. Then, the V-cut line 110C is cut by a V-cutting machine or a laser at a lower surface of each of the hard plate units 111 to 118 with respect to the cutting line 110B of the predetermined removal area 110A, where the reservation is not completely cut off. The removal region 110A is a principle, the depth can be controlled at 8 to 16 mils, and the residual thickness can be controlled at 4 to 20 mils to facilitate subsequent fracture.

Next, as shown in FIG. 2B, the respective hard board units 111-118 can be broken along the cutting line 110B via the folding, and the broken removal areas 110A are taken out to reveal the soft board 120. Polyimide film 122.

The following describes in detail how to make an extended circuit board using the above-described soft and hard bonding board 100. Referring to FIG. 1, in the present embodiment, a plurality of hard plate units 111 to 118 arranged in parallel are formed on a hard plate 110 of a predetermined size. In addition, a plurality of flexible boards 120 are joined between the two hard board units, but the same two hard boards are not repeatedly joined, but the two hard board units are sequentially connected in an interlaced manner. According to the above configuration, the eight hard board units 111 to 118 and the seven soft boards 120 can be combined and processed through a subsequent processing process (for example, a via step, a solder resist step, etc.), and the hard board unit is used. The step of removing the predetermined removal region 110A is formed and formed by the folding step to form an extended soft and hard bonding plate. The number of the above-mentioned hard plates 111 to 118 and the soft board 120 is only an example, and can be adjusted according to actual needs.

The hard board 110 is preferably a hard circuit board having a double-sided circuit layer, which may be formed by laminating or layering a glass fiber resin and a patterned copper foil, and formed by curing, and can provide a soft board for assembly. 120 features. The flexible board 120 is preferably a flexible circuit board having a double-sided circuit layer, but may also have a single-sided second circuit layer 124 (as shown in FIG. 2A), which may be made of a polyimide film, an adhesive, and a patterned copper. Made of foil.

Referring to FIGS. 2A and 2B, first, a plurality of cutting lines 110B that are intended to expose a region of the flexible board are cut between the respective hard board units 111 to 118 and the predetermined removal area 110A. Next, the soft boards 120 are bonded to the hard board 110 by a glue layer 130. A plurality of via holes 140 are formed in the hard board 110 and the soft board 120 to electrically conduct the first circuit layer 110D on the hard board 110 and the second circuit layer 124 on the soft board 120. Thereafter, V-shaped cutting lines 110C are formed correspondingly along the cutting lines 110B on the hard plate 110, and the predetermined removal regions 110A are respectively broken to expose the respective soft plates 120, and the hard plate units 111 to 118 are molded.

The via hole 140 is implemented as follows: (1) a through hole 140A communicating with the soft board 120 and the hard board 110 is drilled using a drill, and preferably, the diameter of the through hole 140A is 0.2 mm to 3.175. (2) Electroplating the via hole 140A to electrically conduct the first circuit layer 110D on each of the hard plates 110 and the second circuit layer 124 on each of the soft plates 120. Generally, before the electroplating, the through hole 140A is subjected to the desmear operation, and then a direct current is passed through the plating solution to perform a chemical reduction reaction to make the first circuit layer 110D on the hard plate 110 and the first on the soft board 120. The two wiring layers 124 are electrically connected to the conductive layer 140A in the via hole 140B, and the thickness of the conductive layer 140A can be controlled to be 0.5 to 2 mils.

After the via 140 is completed, a solder resist layer 142 may be applied on the second wiring layer 124 of the flexible board 120 and the first wiring layer 110D of the hard board 110 to prevent oxidation or solder contamination of the wiring layer, but reveal The contact points C1 and C2 are outside the solder resist layer 142 as a joint surface for signal transmission.

Please refer to the folding sequence diagram of FIG. 3A to FIG. 3G, which representatively shows the folding order of four hard boards, but also applies to a larger number of hard boards. First, as shown in FIGS. 3A to 3C, the first rigid plate unit 111 is folded to the left so that the soft plate 120 is folded to the left along the vertical folding line L1, and then the soft plate 120 is further down along the horizontal folding line L2. The partial folding of the flexible panel 120 is overlapped with another partial area of the flexible panel 120. Next, as shown in FIG. 3D and FIG. 3E, the third hard board unit 113 and the fourth hard board unit 114 are folded to the right so that the soft board 120 is folded rightward along the vertical folding line L1, and then the soft board is further along The horizontal folding line L2 is folded upward to overlap a portion of the soft board 120 over another portion of the soft board 120. Next, as shown in FIG. 3F and FIG. 3G, the fourth rigid board unit 114 is folded to the right so that the soft board 120 is folded rightward along the vertical folding line L1, and then the soft board 120 is further down along the horizontal folding line L2. The partial folding of the flexible panel 120 is overlapped with another partial area of the flexible panel 120. In FIG. 3G, all of the first to fourth hard plate units 111 to 114 are arranged in the extending direction. Thus, the extended soft and hard bonding plate 100a is substantially completed, so the length S2 (second length) of the soft and hard bonding plate 100a after folding is greater than the original length S1 (first length) of the soft and hard bonding plate 100 before folding is greater than the original A printed circuit board produces a circuit board of a predetermined size on the device. Therefore, it is not limited by the production equipment of printed circuit boards.

Please refer to the folding diagram of FIG. 4A and FIG. 4B. In another embodiment, the two folding lines on the flexible board 220 are not limited to vertical folding lines and horizontal folding lines, and may also be folding lines on the diagonal line. First, the first hard board unit 211 is folded downward so that the soft board 220 is folded down along the horizontal folding line L3, and then the second hard board unit 212 is folded upward so that the soft board 220 is upward along the diagonal folding line L4. In half, a portion of the area of the flexible board 220 is overlapped with another portion of the flexible board 220. Thus, the second rigid plate unit 212 and the first hard plate unit 211 are L-shaped at right angles, not arranged in the longitudinal direction. Therefore, the invention can manufacture soft and hard combination boards of different folding methods according to the requirements of the customer, so as to meet the requirements of customization.

In summary, the manufacturing method of the soft and hard bonding board of the present invention overcomes the obstacle that cannot be broken in size, and can be combined into an extended soft and hard bonding board by folding the hard board to extend in the same direction or in different directions, thereby improving The defects of the existing production methods and the convenience of subsequent assembly can be widely applied to the industries of electronic products such as panels, mobile phones, and memory modules.

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 board

100a. . . Extended soft and hard board

110. . . hard Board

110A. . . Scheduled removal area

110B. . . Cutting line

110C. . . V-cut line

110D. . . First circuit layer

111～118. . . Hard board unit

120. . . Soft board

122. . . Polyimide film

124. . . Second circuit layer

130. . . Glued layer

132. . . Deflection location

140. . . Via

140A. . . Conductive layer

140B. . . Through hole

142. . . Solder mask

211, 212. . . Hard board unit

220. . . Soft board

C1, C2. . . contact

L1, L2. . . Folding line

L3, L4. . . Folding line

FIG. 1 is a schematic view showing a soft and hard bonding board in an unfolded state according to an embodiment of the present invention.

2A to 2B are schematic cross-sectional views of a soft and hard bonding board cut perpendicularly to the folding line of Fig. 1.

3A to 3G are schematic views showing the folding sequence of the soft and hard bonding board according to the present invention.

4A-4B are schematic views showing the folding of the soft and hard bonding board according to another embodiment of the present invention.

100. . . Soft and hard board

110. . . hard Board

111～118. . . Hard board unit

120. . . Soft board

110A. . . Scheduled removal area

L1, L2. . . Folding line

Claims (8)

A method for manufacturing a soft and hard bonding board, comprising: providing a hard board having a first circuit layer, and a plurality of soft boards having a second circuit layer, the hard board comprising a predetermined removal area and a plurality of hard boards a cutting line that cuts a plurality of areas that are intended to expose the soft board between the hard board unit and the predetermined removal area; bonding the soft boards to the hard board by using a glue layer; forming a plurality of through holes The hard board and the soft boards electrically electrically connect the first circuit layer on the hard board and the second circuit layer on the flexible board; and the predetermined shifts are respectively broken along the cutting lines on the hard board In addition to the area, the respective flexible boards are exposed and the hard board units are formed; and the respective soft boards are folded in half along the respective plurality of folding lines so that the hard board units are arranged to extend in one direction. The method for manufacturing a soft and hard bonding board according to the first aspect of the invention, wherein the folding step of the soft board comprises: sequentially folding a soft board along a vertical folding line; folding the soft board in a horizontal folding line; The partial area of the flexible board is overlapped with another part of the soft board. A method for manufacturing a soft and hard bonding board, comprising: providing a two-hard board unit and a soft board, wherein the soft board is joined between the two hard board units by a glue layer, so that the soft and hard board has a first length And folding a plurality of folding lines along the flexible board such that the soft and hard bonding board has a second length along the first length, the second length being greater than the first length. The method for manufacturing a soft and hard bonding board according to claim 3, wherein the hard boards are rigid circuit boards having double-sided circuit layers. The method for manufacturing a soft and hard bonding board according to claim 3, wherein the flexible board is a flexible circuit board having a double-sided circuit layer. The method for manufacturing a soft and hard bonding board according to the third aspect of the invention, wherein the bonding of the soft and hard bonding board further comprises forming a plurality of via holes in the soft board and the two hard board units. The method for manufacturing a soft and hard bonding board according to the third aspect of the invention, wherein the folding step of the soft board comprises: folding along a vertical folding line; and folding along a horizontal folding line to make one of the soft boards A portion of the area overlaps another portion of the soft board. The method for manufacturing a soft and hard bonding board according to the third aspect of the invention, wherein the folding step of the soft board comprises: folding in a horizontal folding line; and folding along a pair of corner folding lines to make the soft board A portion of the area overlaps another portion of the flexible board.