The subject matter herein generally relates to circuit boards, in particular, to a circuit board assembly formed by connecting a plurality of circuit boards and a method for manufacturing the circuit board assembly.
Functions of electronic products are always increasing, which leads to the number of circuit boards in the electronic products being increased. These circuit boards need to be electrically connected. The circuit boards are generally connected through a hot bar process. However, the hot bar process includes a reflow soldering process which process is complicated.
Implementations of the present technology will now be described, by way of embodiment, with reference to the attached figures.
It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure.
Several definitions that apply throughout this disclosure will now be presented.
The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other feature that the term modifies, such that the component need not be exact. For example, “substantially cylindrical” means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the like.
A method for manufacturing a circuit board assembly according to an embodiment includes steps as follows.
Step S1, referring to
The first insulating layer 11 is made of a flexible insulating material, which is selected from a group consisting of liquid crystal polymer (LCP), poly tetra fluoro ethylene (PTFE), poly ether ether ketone (PEEK), polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene (PE), and any combination thereof.
Step S2, referring to
Step S3, referring to
In this embodiment, a coating is formed on a wall of the through hole 101, through an electroplating process, to obtain the first conductive structure 21. It can be understood that when the first conductive structure 21 is formed by electroplating, the coating is also formed on surfaces of the copper layers 12 facing away from the first insulating layer 11. In other embodiments, the first conductive structure 21 is formed by filling the through hole 101 with conductive materials.
Step S3, referring to
One of the first conductive wiring layers 13 includes a plurality of lines 131 and a plurality of first contact pads 132. The first contact pads 132 are coupled to the lines 131, respectively. The first contact pads 132 are adjacent to an end of the first insulating layer 11 and are parallel with each other.
Step S4, referring to
The first protective layers 31 are configured to protect the first conductive wiring layers 13. The first protective layers 31 are cover films which are bonded to the first conductive wiring layers 13 or printed ink layers formed on the first conductive wiring layers 13.
The first circuit board 40 includes a first surface 401 with the first contact pads 132 and a second surface 402 opposite to the first surface 401. The two first protective layers 31 are respectively located on the first surface 401 and the second surface 402.
Step S5, referring to
Step S6, referring to
Step S7, referring to
The stamped protrusions 51 protrude out of the first surface 401. A plurality of stamped grooves 52 are formed on the second surface 402, the stamped groove 52 corresponding in position to the stamped protrusions 51. Each stamped groove 52 has a shape matching that of a corresponding stamped protrusion 51. In this embodiment, a cross section of each stamped protrusion 51 is arc-shaped. In other embodiments, the cross section of each stamped protrusion 51 can be triangular, rectangular, trapezoidal, etc. It can be understood, each stamped protrusion 51 and the corresponding stamped groove 52 are formed simultaneously during a stamping process.
Step S8, referring to
In some embodiments, an adhesive layer 70 is sandwiched between the supporting block 60 and the first circuit board 40, the supporting block 60 is bonded to the first circuit board 40 through the adhesive layer 70.
The adhesive layer 70 may include a viscous resin. The viscous resin may be at least one of polypropylene, epoxy, polyurethane, phenolic, urea-formaldehyde, melamine-formaldehyde and polyimide.
Step S9, referring to
In this embodiment, the second circuit board 80 includes two second conductive wiring layers 83 which are arranged on opposite surfaces of the second insulating layers 81. The two second conductive wiring layers 83 are electrically connected with each other through a second conductive structure 42 which penetrates the second insulating layer 81. The second conductive structure 42 is a hole which is metallized or a conductive column. In other embodiment, the second circuit board 80 can include only one second conductive wiring layer 83.
The second circuit board 80 further includes two second protective layers 32. The second protective layers 32 cover surfaces of the second conductive wiring layers 83 facing away from the second insulating layer 81. The second contact pads 832 of one second conductive wiring layer 83 are exposed from a corresponding second protective layer 32. The second protective layers 32 are cover films or can be layers of ink.
The second insulating layer 81 is rigid. The second insulating layer 81 can be made of a resin material containing glass fibers.
In some embodiment, another supporting block 60 is arranged on the second protective layer 32 of the second circuit board 80. The supporting block 60 on the second circuit board 80 is configured to connect to the supporting block 60 on the first circuit board 40. In other embodiments, there is only one supporting block 60 arranged between the first circuit board 40 and the second circuit board 80.
Step S10, referring to
The supporting block 60 is sandwiched between the first circuit board 40 and the second circuit board 80. Since the height of the stamped protrusion 51 is greater than the height of the supporting block 60, the stamped protrusion 51 will deform under pressure and its height will be reduced when the first circuit board 40 is pressed onto the second circuit board 80, thereby the supporting block 60 can make contact with the second circuit board 80, and an area of contact between the first contact pad 132 and the corresponding second contact pad 832 is thus increased The first contact pad 132 is thus in close contact with the corresponding second contact pad 832 to maintain good conductivity.
In some embodiments, another adhesive layer 70 is sandwiched between the supporting block 60 and the second circuit board 80. The supporting block 60 is bonded to the second circuit board 80 through the adhesive layer 70.
In this embodiment, two first circuit boards 40 are pressed on opposite surfaces of the second circuit board 80, the stamped protrusions 51 of one first circuit board 40 are in contact with the second contact pads 832 of a corresponding second conductive wiring layer 83.
Step S11, referring to
The encapsulation layer 90 further covers a portion of a surface of the first circuit board 40 facing away from the second circuit board 80, a portion of a side face of the first circuit board 40, a portion of a surface of the second circuit board 80 facing away from the first circuit board 40, and a portion of a side face of the second circuit board 80. The encapsulation layer 90 covers corresponding regions of the first circuit board 40 and the second circuit board 80.
The encapsulation layer 90 is made of a non-conductive material. The non-conductive material includes one or more of epoxy molding compound (EMC), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyethylene terephthalate (PET), and other injection molding materials.
Referring to
Each first circuit board 40 includes the first insulating layer 11, two first conductive wiring layers 13 on opposite surface of the first insulating layer 11, and two first protective layers 31 on surfaces of the two first conductive wiring layers 13 facing away from the first insulating layer 11. One first conductive wiring layer 13 of each first circuit board 40 includes the first contact pads 132 which are exposed from the corresponding first protective layer 31.
Each first circuit board 40 defines one slit 41 (shown in
Each first circuit board 40 further includes the first surface 401 and the second surface 402 opposite to the first surface 401. The first surface 401 defines the stamped protrusions 51 corresponding to the first contact pads 132, and each first contact pad 132 is outside a stamped protrusion 51. The second surface 402 defines the stamped grooves 52 having shapes matching the shapes of the stamped protrusions 51.
In other embodiments, the first conductive wiring layer 13 includes only one first contact pad 132, and the second conductive wiring layer 83 includes only one second contact pad 832, and there are only one stamped protrusion 51 being correspondingly positioned relative to a position of the first contact pad 132.
The second circuit board 80 includes the second insulating layer 81, two second conductive wiring layers 83 on opposite surfaces of the second insulating layer 81, and two second protective layers 32 on surfaces of the two second conductive wiring layers 83 facing away from the second insulating layer 81. Each second conductive wiring layer 83 includes the second contact pads 832 which are exposed from the corresponding second protective layer 32.
Each first contact pad 132 of the stamped protrusion 51 of one first circuit board 40 is in contact with a second contact pad 832 of one second conductive wiring layer 83, so that the two first circuit boards 40 are electrically coupled to the second circuit board 80.
In some embodiments, the circuit assembly further includes two supporting blocks 60, one supporting block 60 is sandwiched between one first circuit board 40 and the second circuit board 80, and the other supporting block 60 is sandwiched between the other first circuit board 40 and the second circuit board 80. Each supporting block 60 is adjacent to the stamped protrusions 51 of one first circuit board 40.
In some embodiments, each supporting block 60 is bonded to one first circuit board 40 and the second circuit board 80 by two respective adhesive layers 70.
In some embodiments, the circuit board assembly further includes the encapsulation layer 90. The encapsulation layer 90 infills gaps between the first circuit boards 40 and the second circuit board 80 and encapsulates and seals the first contact pads 132 and the second contact pads 832.
In the circuit board assembly and the manufacturing method, the first contact pads 132 of the first circuit board 40 are in contact with the second contact pads 832 of the second circuit board 80, so that electronic connections between the first circuit board 40 and the second circuit board 80 are achieved. Compared with a hot bar process, neither a solder paste nor a reflow soldering process is required, the process is simplified. Moreover, the encapsulation layer 90 encapsulates the first contact pad 132 and the connected second contact pads 832 to seal against the air, improving the reliability.
While the present disclosure has been described with reference to particular embodiments, the description is illustrative of the disclosure and is not to be construed as limiting the disclosure. Therefore, those of ordinary skill in the art can make various modifications to the embodiments without departing from the scope of the disclosure as defined by the appended claims.
Number | Date | Country | |
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Parent | PCT/CN2021/101044 | Jun 2021 | US |
Child | 18094506 | US |