Rigid-flex board and multi-layer flexible board stacking process

Abstract

The invention provides a rigid-flex board and a multilayer flexible board stacking process, and belongs to the technical field of circuit board preparation. The stacking process of the rigid-flex board and the multi-layer flexible board comprises the steps of drilling, electroplating, inner-layer circuit etching, protective glue curing, p < l > asma plasma surface roughening, flexible board ink printing, chemical gold, flying probe testing, flexible board laser processing, P film false connection, P film rapid pressing, flexible board and rigid board combination, rigid-flex pressing, drilling, p < l > asma plasma glue removal, electroplating, outer-layer circuit, solder mask, pre-forming, reinforcement pressing, chemical gold and character. Forming, laser cutting, uncovering, flying probe testing, flexible board appearance laser cutting, P I film tearing, Array forming, visual inspection, packaging and warehousing are carried out. According to the stack-up process of the scheme, by changing the press-fit structure, no indentation exists between the flexible boards, the inner-layer ink does not crack or fall off, the circuit does not deform, and the risk of copper wire fracturing in the circuit is reduced; the product yield is further improved, and the product competitiveness in the fields of multi-layer flexible boards and rigid-flex boards is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board preparation, and in particular to a rigid-flexible board and a multi-layer flexible board stacking process. Background Art

[0002] With the birth and development of FPC and PCB, a new product called rigid-flex board was born. Therefore, rigid-flex board is a circuit board with both FPC and PCB characteristics formed by combining flexible circuit board and rigid circuit board through lamination and other processes according to relevant process requirements.

[0003] Initially, the basic design concept and manufacturing process of multi-layer rigid-flex PCB were developed from aerospace equipment, because reliable wiring was required in a limited space. In some complex products, rigid-flex PCB with more than 30 conductor layers is even used. On the other hand, in consumer electronic products, such as mobile phones and digital cameras, high-density and low-cost wiring technology has always been required, so new design concepts and manufacturing processes came into being.

[0004] The combination of soft and rigid boards can be called rigid-flex boards, rigid-flex boards, or rigid-flex boards. When their multi-layer flexible media use flexible materials instead of glass-epoxy resin, they are also called multi-layer flexible boards. Multi-layer rigid-flex boards are basically a combination of rigid boards and flexible boards. However, for circuit board manufacturers to successfully combine the two, they need to have a good level of both rigid and flexible board manufacturing processes.

[0005] In the field of multi-layer soft boards and hard-flex boards, among them, 2+2 (2 refers to double-sided soft boards) stacked products, during the stacking process, a special high-temperature and high-pressure resistant PI material auxiliary material (referred to as PI film) is pasted between the two soft boards and then pressure is transmitted. After the laser cutting of the shape, the PI film between the two soft boards is removed. In the previous operation method, the stacked structure is 2+2 hard-flex boards and multi-layer soft boards. Due to the different circuit patterns of the two double-sided soft boards in the middle, during the high-temperature and high-pressure pressure transmission process, there are problems such as circuit breakage, deformation, appearance indentation, and inner ink fragmentation and shedding after the circuit is pressed together.

[0006] To this end, we need a rigid-flexible board and a multi-layer flexible board stacking process. Summary of the invention

[0007] In order to overcome the problems existing in the related art, the purpose of the present invention is to provide a process for stacking hard-flex boards and multi-layer soft boards. By changing the pressing structure, there is no indentation between the soft boards, the inner layer of ink does not break or fall off, the circuit does not deform, and the risk of copper wire fracturing in the circuit is reduced; the product yield is further improved, and the product competitiveness in the field of multi-layer soft boards and hard-flex boards is improved.

[0008] A process for stacking rigid-flex boards and multi-layer flexible boards, including drilling, electroplating, inner-layer circuit etching, protective glue aging, plasma surface roughening, flexible board ink printing, chemical gold, flying probe test, flexible board laser processing, PI film false connection, PI film fast pressing, flexible board and rigid board combination, flexible-hard pressing, drilling, plasma glue removal, electroplating, outer-layer circuit, solder mask, preforming, reinforcement pressing, chemical gold, text, molding, laser cutting, opening the cover, flying probe test, laser cutting of flexible board shape, tearing PI film, array molding, visual inspection, packaging, and warehousing;

[0009] The PI film joint comprises:

[0010] S1. Remove the release paper on the PI film and stick the PI film on the micro-mucosal membrane;

[0011] S2. Laser cutting of PI film;

[0012] S3. Transfer the PI film between two double-sided soft boards;

[0013] S4. Press the PI film onto the double-sided soft board by fast pressing to remove the micro-adhesive film. The pressing temperature is 80-120° C. and the pressing time is 15-25 s.

[0014] In a preferred technical solution of the present invention, in said S4, the pressing temperature is 90-110°C;

[0015] In a preferred technical solution of the present invention, in said S4, the pressing time is 18-22s;

[0016] In a preferred technical solution of the present invention, during the soft-hard pressing process, the pressure is 80-230N / qcm; the soft-hard pressing holding time is 1-160min; the soft-hard pressing pressure slope is 0-30min;

[0017] In a preferred technical solution of the present invention, during the soft-hard pressing process, the pressure is 100-210N / qcm; the soft-hard pressing holding time is 2-145min; the soft-hard pressing pressure slope is 0-20min;

[0018] The soft-hard pressing pressure slope refers to the time it takes for the pressure to rise evenly from 100 N / qcm in the previous step to 160 N / qcm in the next step;

[0019] In a preferred technical solution of the present invention, during the soft-hard pressing process, the heating temperature is 20-250°C; the soft-hard pressing heating time is 1-150min; and the soft-hard pressing temperature slope is 3-30min.

[0020] In a preferred technical solution of the present invention, during the soft-hard pressing process, the heating temperature is 40-210°C; the soft-hard pressing heating time is 2-130min; and the soft-hard pressing temperature slope is 5-25min.

[0021] The soft-hard pressing temperature slope refers to the time it takes for the temperature to rise from 60°C in the previous step to 80°C in the next step;

[0022] In a preferred technical solution of the present invention, during the PI film tearing process, after the laser cutting of the outer shape, the two soft boards are separated and the PI film between the two soft boards is removed.

[0023] In a preferred technical solution of the present invention, the working temperature of the PI film is -269°C to 400°C.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides a rigid-flexible board and a multi-layer flexible board stacking process.

[0026] 1. A layer of PI film is pasted in the middle of the flexible board to avoid high temperature and high pressure, and the circuit patterns between the flexible boards are inconsistent, which leads to the fracturing and deformation of the copper circuit and the indentation on the product appearance;

[0027] 2. The PI film isolates the inner layer ink from contact with the soft board, preventing the inner layer soft board ink from breaking and falling off after high temperature and high pressure;

[0028] 3. The stacking process of the present invention has no pollution to the product and is easy to operate;

[0029] 4. Improve product yield and achieve zero risk of circuit breakage for multi-layer soft boards and 2+2 structure products of soft-rigid combined boards;

[0030] 5. The stacking process of the present invention can reduce the defective rate of line indentation deformation from 68% to less than 2%; reduce the defective rate of soft board ink cracking and shedding from 83% to 0.6%; and can also achieve no pollution to the product after use. After element analysis of the product surface after film tearing, no other elements other than the specific elements contained in the product itself were found. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the first double-sided soft board in the soft-rigid combination board and multi-layer soft board stacking process provided by the present invention;

[0032] Figure 2 It is a structural schematic diagram of the second double-sided soft board in the soft-rigid combination board and multi-layer soft board stacking process provided by the present invention;

[0033] Figure 3It is a structural schematic diagram of two double-sided soft boards stacked in the soft-rigid combination board and multi-layer soft board stacking process provided by the present invention. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms of "a", "said" and "the" used in the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0036] It should be understood that although the terms "first", "second", "third", etc. may be used to describe various information in the present invention, the information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other.

[0037] Unless otherwise specified, the methods and equipment used in the present invention are all conventional reagents, methods and equipment in the art.

[0038] The equipment used in the following embodiments is as follows:

[0039] PI film: working temperature: -269℃ to 400℃; product model: AHIPI520XSS1; manufacturer: Yasen;

[0040] Example 1

[0041] A process for stacking rigid-flex boards and multi-layer flexible boards, including drilling, electroplating, inner-layer circuit etching, protective glue aging, plasma surface roughening, flexible board ink printing, chemical gold, flying probe test, flexible board laser processing, PI film false connection, PI film fast pressing, flexible board and rigid board combination, flexible-hard pressing, drilling, plasma glue removal, electroplating, outer-layer circuit, solder mask, preforming, reinforcement pressing, chemical gold, text, molding, laser cutting, opening the cover, flying probe test, laser cutting of flexible board shape, tearing PI film, array molding, visual inspection, packaging, and warehousing;

[0042] PI film joints include:

[0043] S1. Remove the release paper on the PI film and stick the PI film on the micro-mucosal membrane;

[0044] S2. Laser cutting of PI film;

[0045] S3. Transfer the PI film between two double-sided soft boards;

[0046] S4. Use fast pressing to press the PI film onto the double-sided soft board to remove the micro-adhesive film. The pressing temperature is 80-120℃ and the pressing time is 15-25s.

[0047] In S4, the pressing temperature is 90-110°C;

[0048] In S4, the pressing time is 18-22s;

[0049] During the soft and hard pressing process, the pressure is 100-210N / qcm; the soft and hard pressing holding time is 2-145min; the soft and hard pressing slope is; during the soft and hard pressing process, the heating temperature is 40-210℃; the soft and hard pressing heating time is 2-130min.

[0050] The specific process parameters are as follows:

[0051]

[0052] During the PI film tearing process, after laser cutting the shape, the two soft boards are separated and the PI film between the two soft boards is removed.

[0053] The operating temperature of PI film is -269℃ to 400℃.

[0054] The present invention provides a rigid-flexible board and a multi-layer flexible board stacking process.

[0055] 1. A layer of PI film is pasted in the middle of the flexible board to avoid high temperature and high pressure, and the circuit patterns between the flexible boards are inconsistent, which leads to the fracturing and deformation of the copper circuit and the indentation on the product appearance;

[0056] 2. The PI film isolates the inner layer ink from contact with the soft board, preventing the inner layer soft board ink from breaking and falling off after high temperature and high pressure;

[0057] 3. The stacking process of the present invention has no pollution to the product and is easy to operate;

[0058] 4. Improve product yield and achieve zero risk of circuit breakage for multi-layer soft boards and 2+2 structure products of soft-rigid combined boards;

[0059] 5. The stacking process of the present invention can reduce the defective rate of line indentation deformation from 68% to less than 2%; reduce the defective rate of soft board ink cracking and shedding from 83% to 0.6%; and can also achieve no pollution to the product after use. After element analysis of the product surface after film tearing, no other elements other than the specific elements contained in the product itself were found.

[0060] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The embodiments of the present application have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Without departing from the scope and spirit of the described embodiments, many modifications and changes are obvious to those of ordinary skill in the art. The choice of terms used in this article is intended to best explain the principles of the embodiments, practical applications or improvements to the technology in the market, or to enable other ordinary technicians in the technical field to understand the embodiments disclosed herein.

Claims

1. A process for stacking rigid-flex boards and multi-layer flexible boards, including drilling, electroplating, inner layer circuit etching, protective glue maturation, plasma surface roughening, flexible board ink printing, chemical gold, flying probe test, flexible board laser processing, PI film false connection, PI film fast pressing, flexible board and rigid board combination, flexible and rigid pressing, drilling, plasma glue removal, electroplating, outer layer circuit, solder mask, preforming, reinforcement pressing, chemical gold, text, molding, laser cutting, opening the cover, flying probe test, laser cutting of flexible board shape, tearing PI film, Array molding, visual inspection, packaging, and warehousing; Features ； The PI film joint comprises: S1. Remove the release paper on the PI film and stick the PI film on the micro-mucosal membrane; S2. Laser cutting of PI film; S3. Transfer the PI film between two double-sided soft boards; S4. Press the PI film onto the double-sided soft board by fast pressing to remove the micro-adhesive film. The pressing temperature is 80-120° C. and the pressing time is 15-25 s.

2. The rigid-flex board and multi-layer flexible board stacking process according to claim 1, characterized in that: In the step S4, the pressing temperature is 90-110°C.

3. The rigid-flex board and multi-layer flexible board stacking process according to claim 1, characterized in that: In S4, the pressing time is 18-22s.

4. The rigid-flex board and multi-layer flexible board stacking process according to claim 1, characterized in that: During the soft-hard pressing process, the pressure is 80-230 N / qcm; the soft-hard pressing holding time is 1-160 min; and the soft-hard pressing pressure slope is 0-30 min.

5. The rigid-flex board and multi-layer flexible board stacking process according to claim 4, characterized in that: During the soft-hard pressing process, the pressure is 100-210 N / qcm; the soft-hard pressing holding time is 2-145 min; and the soft-hard pressing pressure slope is 0-20 min.

6. The rigid-flex board and multi-layer flexible board stacking process according to claim 1, characterized in that: During the soft-hard pressing process, the heating temperature is 20-250° C.; the soft-hard pressing heating time is 1-150 min; and the soft-hard pressing temperature slope is 3-30 min.

7. The rigid-flex board and multi-layer flexible board stacking process according to claim 6, characterized in that: During the soft-hard pressing process, the heating temperature is 40-210° C.; the soft-hard pressing heating time is 2-130 min; and the soft-hard pressing temperature slope is 5-25 min.

8. The rigid-flex board and multi-layer flexible board stacking process according to claim 1, characterized in that: In the PI film tearing process, after the laser cutting shape, the two soft boards are separated and the PI film between the two soft boards is removed.

9. The rigid-flex board and multi-layer flexible board stacking process according to claim 1, characterized in that: The working temperature of the PI film is -269°C to 400°C.

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