TW202103528A - Stress relief structures on outer frame of rigid-flex hybrid circuit boards - Google Patents

Abstract

Stress relief structures on outer frame of s rigid-flex hybrid circuit boards are disclosed. In particular, a whole-scale manufactured rigid-flex hybrid circuit board construction comprises: an array of rigid-flex hybrid circuit board units, each of the rigid-flex hybrid circuit board units is connected to one another and composed of a hard board, a flexible board and a contact pad. An outer frame connects and surrounds the array of rigid-flex hybrid circuit board units. A stress relief component includes winding structures winding back and forth and is disposed on the outer frame to eliminate stress generated in the manufacturing processes.

Description

Stress relief structure of outer frame of flexible and hard composite circuit board

The present invention relates to the related technology of stress relief of flexible and hard composite circuit boards, in particular to a stress relief structure for manufacturing the outer frame of flexible and rigid composite circuit boards in a whole piece.

As the research and development of electronic devices, such as smartphones, tablets, and notebook computers, are becoming lighter, thinner, and more efficient, the development of their internal components, such as circuit boards, also tends to be miniaturized.化 development. With the demand for lightness and thinness of terminal products, the application range of flexible boards and rigid-flex boards will become wider.

In order to improve the reliability of the connection between the rigid board and the flexible board, the flexible board can be directly fabricated between the two rigid boards to avoid the subsequent additional connection process. This product is called a flexible and rigid composite board, which is also a flexible circuit. The rigid-flex hybrid PCB module formed by combining a flexible circuit board with a rigid circuit board is a direction that the industry is actively promoting and developing.

When manufacturing flexible and hard composite circuit boards, the whole-chip process is mainly used to improve production efficiency. That is, an array composed of a plurality of flexible and hard composite circuit board units is simultaneously manufactured on a whole piece of substrate, and each flexible and hard composite circuit board unit is connected to each other. In addition, an outer frame is included to connect and surround the flexible and hard composite circuit board array. The electronic component chip is assembled on the hard and soft composite circuit board Then, the flexible and hard composite circuit board unit is cut or peeled into the cavity on the board, thereby completing the modularized packaged flexible and rigid composite circuit board structure.

However, when manufacturing a monolithic flexible and hard composite circuit board unit array, various process steps (such as drilling, etching, electroplating, and other process steps) often leave different levels of stress. The cumulative combined effect of various stresses causes warping or unevenness of the whole piece of flexible and hard composite circuit boards, which reduces the accuracy and yield of subsequent manufacturing processes, affects the electrical properties of the final product and reduces the quality reliability.

In view of this, in order to solve the above-mentioned dilemma of the prior art, the present invention provides a one-piece stress relief structure for manufacturing the outer frame of a flexible and hard composite circuit board. The stress relief structure provided on the outer frame effectively eliminates unnecessary stress. And avoid the warping phenomenon of the whole piece of soft and hard composite circuit board.

According to one aspect of the present invention, there is provided a rigid and flexible composite circuit board structure manufactured in one piece, including: a flexible and rigid composite circuit board array, and each flexible and rigid composite circuit board is connected to each other and consists of a rigid board and a flexible circuit board. A composite circuit board composed of a combination of a board and a contact pad; an outer frame that connects and surrounds the flexible and hard composite circuit board array; and a stress relief element including a winding gap structure arranged on the outer frame to eliminate the process The resulting stress.

According to another aspect of the present invention, there is provided a rigid and flexible composite circuit board structure manufactured in one piece, including: a flexible and rigid composite circuit board array, each flexible and rigid composite circuit board is connected to each other and is respectively composed of a rigid board and a flexible circuit board. A composite circuit board composed of a combination of a board and a contact pad; an outer frame connected to and surrounding the flexible and hard composite circuit board array; and a stress relief element arranged at the position of the outer frame corresponding to the soft board, wherein the stress relief element Including the upper and lower layers of overlapping metal lines.

Other aspects of the present invention will partly be described in the following description, and part will be easily known from the description, or can be learned from the implementation of the present invention. The various aspects of the present invention can be understood and achieved by using the elements and combinations specified in the appended patent application scope. It should be understood that the foregoing general description and the following detailed description are for example only, and are not intended to limit the present invention.

100‧‧‧Integral flexible and hard composite circuit board structure

110‧‧‧Soft and hard composite circuit board array

110A‧‧‧Lower layer circuit

110B‧‧‧Upper layer circuit

112‧‧‧Hard Board

114‧‧‧Soft Board

115‧‧‧Soft and hard composite circuit board unit

116‧‧‧Contact pad

120‧‧‧Outer frame

130‧‧‧Stress Relief Components

132‧‧‧Upper line

134‧‧‧Lower Line

136‧‧‧Finger electrode structure

140‧‧‧Stress Relief Components

142‧‧‧The width of the finger electrode

144‧‧‧The gap of the finger electrode

From the detailed description of each embodiment of the present invention, combined with the accompanying drawings, will be able to more fully understand and appreciate the present invention, where the drawings are: Figures 1A and 1B respectively show the one piece manufactured according to the embodiment of the present invention A schematic plan view of the lower layer circuit and the upper layer circuit of the flexible and hard composite circuit board structure; FIG. 2 shows the stress relief element according to an embodiment of the present invention including an upper circuit, a lower layer circuit, and upper and lower layer overlapping metal circuits; FIG. 3A shows an implementation according to the present invention For example, a schematic diagram of the relative size of the length X and the width Y of the stress relief element; and FIG. 3B shows a schematic diagram of the relative size of the width B and the electrode gap A of the interdigitated electrode according to an embodiment of the present invention.

The present invention discloses a stress relief element arranged on the outer frame of a monolithic flexible and hard composite circuit board to eliminate the stress generated in the manufacturing process, avoid affecting the accuracy of the subsequent manufacturing process and effectively improve the integrated rigid and flexible circuit board The flatness.

In order to make the description of the present invention more detailed and complete, please refer to the following description in conjunction with the accompanying drawings, in which similar component symbols represent similar components. However, the devices, components, and program steps described in the following embodiments are only used to illustrate the present invention, and are not used to limit the scope of the present invention.

Figures 1A and 1B respectively show the schematic diagrams of the lower circuit 110A and the upper circuit 110B of the monolithic flexible and hard composite circuit board structure. Through the superposition of the upper and lower circuits 110A and 110B, the whole piece of flexible and hard composite circuit board structure is formed 100. The monolithic flexible and hard composite circuit board structure includes a flexible and hard composite circuit board array 110, and each flexible and hard composite circuit board unit 115 is connected to each other and is respectively composed of a rigid board 112, a flexible board 114 and a contact pad 116. For the composite circuit board, please refer to the partial enlarged part 1A of Figure 1A. An outer frame 120 connected to and surrounds the flexible and hard composite circuit board array Column 110. A stress relief element 130 including a winding slit structure is disposed on the outer frame to eliminate the stress generated during the manufacturing process. Please refer to the partial enlarged part 1B of FIG. 1B.

The rigid board 112 and the contact pad 116 can be made of rigid circuit boards made of the same material and height. The material of the hard board 112 and the contact pad 116 includes an epoxy resin substrate, a phenolic resin substrate, a polyimide substrate, a polyamine formaldehyde substrate, a glass fiber substrate, a Teflon substrate, or any combination of the foregoing materials. The soft board 114 is a flexible substrate including polyimide (PI).

In an embodiment of the present invention, the stress relief element 130 is disposed at a position of the outer frame corresponding to the soft board 114. In another embodiment of the present invention, depending on the effect of stress relief, an additional stress relief element (not shown) is added, and it is selected to be located at the position of the outer frame corresponding to the rigid board.

Please refer to FIG. 2, the stress relief element includes metal lines with upper and lower layers overlapping 132 and 134. The upper and lower layers are respectively overlapping and staggered interdigitated electrode structures 136, as shown in the right diagram of FIG. 2.

In one embodiment, the stress relief element is disposed at a position parallel to the outer frame corresponding to the soft board area, and the length X of the stress relief element 140 is equivalent to the length of the soft board area. If the length X of the soft board area is greater than 15mm, the stress relief element can be divided into two sections with a distance of about 1.0mm between each other. The width Y of the stress relief element 140 is substantially equivalent to the width of the outer frame, as shown in FIG. 3A. In a preferred embodiment, the upper and lower layers have overlapping and staggered interdigitated electrode structures. The interdigitated electrode has a width 142 of about 610 μm and an electrode gap 144 of about 290 μm, as shown in FIG. 3B.

The subsequent manufacturing process includes mounting electronic component chips in the cavities on the rigid board of the flexible and hard composite circuit board, and then cutting or peeling each unit of the flexible and rigid composite circuit board to complete the flexible and hard composite of the modular package. Circuit board structure.

The stress relief element of the embodiment of the present invention provides a structure equivalent to the function of a bridge expansion joint, such as a finger-like, serpentine-like surround, zigzag or other similar structure, to Buffer the stress generated in each manufacturing process to ensure the flatness of the integral flexible and hard composite circuit board.

Although the present invention is disclosed in various embodiments as above, it is not intended to limit the scope of the present invention. Anyone with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. . The scope of protection of the present invention shall be subject to those defined by the attached patent scope.

100‧‧‧Integral flexible and hard composite circuit board structure

110‧‧‧Soft and hard composite circuit board array

110A‧‧‧Lower layer circuit

112‧‧‧Hard Board

114‧‧‧Soft Board

115‧‧‧Soft and hard composite circuit board unit

116‧‧‧Contact pad

120‧‧‧Outer frame

Claims (10)

A whole piece of flexible and hard composite circuit board structure, including: a flexible and hard composite circuit board array, each of the flexible and hard composite circuit boards are connected to each other and is composed of a rigid board, a flexible board and a contact pad. Circuit board; an outer frame connected to and surrounding the flexible and hard composite circuit board array; and a stress relief element, including a winding slit structure arranged on the outer frame, to eliminate the stress generated in the manufacturing process. The flexible and hard composite circuit board structure described in the first item of the patent application, wherein the material of the rigid board and the contact pad includes an epoxy resin substrate, a phenolic resin substrate, a polyimide substrate, a polyamine formaldehyde substrate, and glass fiber Substrate, Teflon substrate or any combination of the above materials. The flexible and hard composite circuit board structure described in the first item of the scope of patent application, wherein the flexible board is a flexible substrate including polyimide In the flexible and hard composite circuit board structure described in item 1 of the scope of patent application, the stress relief element is arranged at the position of the outer frame corresponding to the flexible board. The flexible and hard composite circuit board structure described in item 1 of the scope of the patent application further includes an additional stress relief component arranged at the position of the outer frame corresponding to the rigid board. The stress relief element described in item 1 of the scope of patent application, wherein the stress relief element includes upper and lower layers of overlapping metal lines. As for the stress relief device described in item 6 of the scope of patent application, the upper and lower layers are respectively overlapping and staggered interdigitated electrode structures. A whole piece of flexible and hard composite circuit board structure, including: a flexible and hard composite circuit board array, each of the flexible and hard composite circuit boards are connected to each other and is composed of a rigid board, a flexible board and a contact pad. Circuit board; an outer frame connected to and surrounding the flexible and hard composite circuit board array; and a stress relief element arranged at the position of the outer frame corresponding to the soft board, wherein the stress relief element includes upper and lower layers of overlapping metal lines. As described in item 8 of the scope of patent application, the rigid-flex composite circuit board structure further includes an additional stress relief element arranged at the position of the outer frame corresponding to the rigid board. As for the stress relief device described in item 8 of the scope of patent application, the upper and lower layers are respectively overlapping and staggered interdigitated electrode structures.

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