TW202247730A - Multilayer circuit board and method for manufacturing the same - Google Patents

Abstract

A method for manufacturing a multilayer circuit board includes setting a first groove and a second groove around a first blind hole and a second blind hole, respectively. A first conductive paste block protruding from a first insulating layer and a second conductive paste block protruding from a second insulating layer are respectively filled into the first groove and the second groove to restrict the flow of the first conductive paste block and the second conductive paste block. It can avoid the problem that an overflow area of conductive paste is too large to connect with a peripheral circuit, which leads to short circuit, or the overflow copper paste forms capacitance with the upper and lower copper layers. It is benefit to a high-density design of a multilayer circuit board, and it may improve a quality of the multilayer circuit board. The multilayer circuit board is also provided.

Description

Multilayer circuit board and its manufacturing method

The invention relates to the technical field of circuit board manufacturing, in particular to a multilayer circuit board and a manufacturing method thereof.

Multi-layer circuit boards (generally referring to 3 layers and above) mostly use conductive materials to plug holes to realize any layer interconnection, which can effectively reduce the difficulty of making circuit boards, shorten the production process of circuit boards, and is more environmentally friendly. Therefore, this technology Has broad development prospects.

At present, the commonly used conductive material is conductive paste. Conductive paste is an adhesive with certain conductive properties after curing or drying. It usually uses matrix resin and conductive particles as the main components. The conductive particles are combined by the bonding effect of the matrix resin. Together, a conductive path is formed. However, in the actual high-temperature lamination process, the conductive paste is easy to overflow, causing a short circuit between holes in the layer, which seriously affects the quality of the circuit board.

In view of this, in order to overcome at least one of the above defects, it is necessary to provide a method for manufacturing a circuit board.

It is also necessary to provide a circuit board manufactured by the above method for manufacturing a circuit board.

The invention provides a method for manufacturing a multilayer circuit board, the method comprising:

At least one first circuit board is provided, the first circuit board includes a stacked first insulating layer and a first conductive circuit layer, the first insulating layer is provided with a first blind hole and a At least one first groove around the first blind hole, a first conductive paste block electrically connected to the first conductive circuit layer is provided in the first blind hole, and the first conductive paste block protrudes out of the first Insulation.

At least one second circuit board is provided, the second circuit board includes a stacked second insulating layer and a second conductive circuit layer, a second blind hole is provided in the second insulating layer and a second blind hole is located in the second blind hole At least one second groove around the second blind hole, a second conductive paste block electrically connected to the second conductive circuit layer is provided in the second blind hole, and the second conductive paste block protrudes out of the second Insulation.

Stacking at least one first circuit board and at least one second circuit board to obtain an intermediate body.

And, pressing the intermediate body so that the first conductive paste block and the second conductive paste block are respectively filled in the first groove and the second groove, wherein the The first conductive paste block in a blind hole forms a first conductive portion, the first conductive paste block in the first groove forms a first overflow portion, and the first conductive paste block in the second blind hole forms a first overflow portion. Two conductive paste blocks form the second conductive portion, and the second conductive paste block located in the second groove forms the second overflow portion, thereby obtaining the multilayer circuit board.

In the implementation manner of the present application, the making of the first circuit board includes:

A first circuit substrate is provided, and the first circuit substrate includes the first insulating layer and the first conductive circuit layer stacked.

A first release film is formed on the first insulating layer.

At least one first blind hole is opened through the first insulating layer, the first blind hole also passes through the first peeling film, and the diameter of the first blind hole is from the first peeling film to the The direction of the first insulating layer gradually decreases.

Filling conductive paste into each of the first blind holes to obtain the first conductive paste block, wherein the first conductive paste block includes a first end surface away from the first conductive circuit layer.

At least one first groove is defined in the first insulating layer around the first end surface, and the first groove penetrates through the first peeling film.

And, removing the first peeling film, so that the first end surface protrudes from the first insulating layer, so as to obtain the first circuit board.

In the implementation manner of the present application, the production of the second circuit board includes:

A second circuit substrate is provided, and the second circuit substrate includes the second insulating layer and the second conductive circuit layer stacked.

A second release film is formed on the second insulating layer.

At least one second blind hole is opened through the second insulating layer, the second blind hole also passes through the second peeling film, and the diameter of the second blind hole is from the second peeling film to the The direction of the second insulating layer gradually decreases.

Filling conductive paste into each of the second blind holes to obtain the second conductive paste block, wherein the second conductive paste block includes a second end surface away from the second conductive circuit layer.

At least one second groove is provided on the second insulating layer around the second end surface, and the second groove penetrates through the second peeling film.

And, removing the second peeling film, so that the second end surface protrudes from the second insulating layer, so as to obtain the second circuit board.

In the embodiment of the present application, the first groove is an annular groove, and the first groove surrounds the first conductive paste block; and/or the second groove is an annular groove, and the second The groove surrounds the second conductive paste block.

In the embodiment of the present application, the number of the first grooves is multiple, the multiple first grooves are arranged concentrically, and the depths of the multiple first grooves are sequentially along the direction away from the first blind hole increase or decrease sequentially; and/or, the number of the second grooves is multiple, the multiple second grooves are arranged concentrically, and the depths of the multiple second grooves are along the distance away from the second grooves. The direction of blind holes increases or decreases sequentially.

In the embodiment of the present application, the number of the first grooves is multiple, and the cross section of each of the first grooves is at least one of rectangle, circle and trapezoid; and/or the second groove The number is multiple, and the cross section of each second groove is at least one of rectangle, circle and trapezoid.

In the implementation manner of the present application, after the pressing step, both the first conductive paste block and the second conductive paste block are trapezoidal.

The present invention also provides a multilayer circuit board, which includes: at least one first circuit board and at least one second circuit board. The first circuit board includes a stacked first insulating layer and a first conductive circuit layer, the first insulating layer is provided with a first blind hole and at least one first groove around the first blind hole , a first conductive portion is disposed in the first blind hole, a first overflow portion is disposed in the first groove, and the first conductive portion is electrically connected to the first conductive circuit layer. The second circuit board includes a stacked second insulating layer and a second conductive circuit layer, and the second insulating layer is provided with a second blind hole and at least one second groove around the second blind hole , the second blind hole is provided with a second conductive part, the second groove is provided with a second overflow part, and the second conductive part is electrically connected with the second conductive circuit layer.

In the embodiment of the present application, the first groove is an annular groove, and the first groove surrounds the first conductive paste block; and/or the second groove is an annular groove, and the second The groove surrounds the second conductive paste block.

In the embodiment of the present application, the number of the first grooves is multiple, the multiple first grooves are arranged concentrically, and the depths of the multiple first grooves are sequentially along the direction away from the first blind hole increase or decrease sequentially; and/or the number of the second grooves is multiple, the multiple second grooves are arranged concentrically, and the depth of the multiple second grooves is along the distance from the second blind The direction of the holes increases or decreases sequentially.

In the embodiment of the present application, the number of the first grooves is multiple, and the cross section of each of the first grooves is at least one of rectangle, circle and trapezoid; and/or the second groove The number is multiple, and the cross section of each second groove is at least one of rectangle, circle and trapezoid.

Compared with the prior art, the preparation method of the multilayer circuit board provided by the present invention is by setting the first groove and the second groove around the first blind hole and the second blind hole respectively, when the first circuit board and the second blind hole During the pressing process of the two circuit boards, the first conductive paste block protruding from the first insulating layer and the second conductive paste block protruding from the second insulating layer are overflow-filled into the first groove and the second groove respectively , the first groove and the second groove can limit the flow of conductive paste, which can avoid the problem of short circuit caused by excessive overflow area of conductive paste and connection with peripheral lines, or the phenomenon that the overflowed copper paste forms capacitance with the upper and lower copper layers. Furthermore, the contact area between the first conductive paste block and the first insulating layer and the contact area between the second conductive paste block and the second insulating layer can be increased, thereby increasing the first The adhesion between the conductive paste block and the first insulating layer, and the adhesion between the second conductive paste block and the second insulating layer, reduce the thickness of the first conductive paste block and the second conductive paste block. Affected by cold and heat treatment, the reliability of the multilayer circuit board is improved.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

In order to further explain the technical means and effects adopted by the present invention to achieve the intended purpose, the present invention will be described in detail below in conjunction with the accompanying drawings and preferred embodiments.

A preferred embodiment of the present invention provides a method for manufacturing a multilayer circuit board, comprising the following steps:

Step S1 , please refer to FIG. 1 , providing at least one first circuit substrate 10 and at least one second circuit substrate 20 .

In this embodiment, the first circuit substrate 10 includes a first insulating layer 101 and a first conductive circuit layer 102 stacked, and the first conductive circuit layer 102 is formed on the surface of the first insulating layer 101 . The second circuit substrate 20 includes a second insulating layer 201 and a second conductive circuit layer 202 stacked, and the second conductive circuit layer 202 is embedded in the second insulating layer 201 . Wherein, the second conductive circuit layer 202 includes a plurality of connection pads 2021 . In this embodiment, two first circuit substrates 10 and two second circuit substrates 20 are provided.

The material of the first insulating layer 101 and the second insulating layer 201 can be selected from epoxy resin (epoxy resin), prepreg (Prepreg, PP), BT resin, polyphenylene oxide (Polyphenylene Oxide, PPO), poly One of resins such as polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). In this embodiment, the materials of the first insulating layer 101 and the second insulating layer 201 are prepreg.

In this embodiment, the thickness T of the first insulating layer 101 and the second insulating layer 201 is both 5-150 microns.

Step S2 , forming a first release film 30 and a second release film 40 on the first insulating layer 101 and the second insulating layer 201 respectively.

In this embodiment, the thicknesses of the first peeling film 30 and the second peeling film 40 are both about 25 microns.

In this embodiment, both the first release film 30 and the second release film 40 are PET films.

Step S3, please refer to FIG. 2 , opening a first blind hole 50 penetrating through the first insulating layer 101 in the first circuit substrate 10 , and the first blind hole 50 also penetrates the first release film 30 , A second blind hole 51 penetrating through the second insulating layer 201 is opened in the second circuit substrate 20 , and the second blind hole 51 also penetrates the second peeling film 40 .

Wherein, the diameter of the first blind hole 50 gradually decreases from the first peeling film 30 to the first insulating layer 101, and the diameter of the second blind hole 51 decreases from the first The direction from the second peeling film 40 to the second insulating layer 201 gradually decreases.

The radius of the end of the first blind hole 50 away from the first conductive circuit layer 102 (that is, the maximum radius of the first blind hole 50 ) is the same as that of the end of the second blind hole 51 away from the second conductive circuit layer 202 The radii (that is, the maximum radius of the second blind hole 51) are approximately the same. As shown in FIG. 9 , the radius defining the blind hole is R, and the radius R is 50-150 microns.

In this embodiment, the radius R is approximately 100 microns.

In this embodiment, both the first blind hole 50 and the second blind hole 51 are formed by laser drilling.

Step S4, please refer to FIG. 3 , fill conductive paste in each of the first blind holes 50 and each of the second blind holes 51 respectively, and after curing, obtain The first conductive paste block 60 and the second conductive paste block 61 electrically connected to the second conductive circuit layer 202 .

Wherein, the first conductive paste block 60 includes a first end surface 601 away from the first conductive circuit layer 102 , and the second conductive paste block 61 includes a second end surface 611 away from the second conductive circuit layer 202 .

In this embodiment, both the first conductive paste block 60 and the second conductive paste block 61 are trapezoidal.

In this embodiment, the conductive paste may be solder paste or copper paste. Specifically, the conductive paste is solder paste.

Step S5, please refer to FIG. 4 , a first groove 70 is opened in the first insulating layer 101 around the first end surface 601, and the first groove 70 penetrates the first release film 30; The second insulating layer 201 around the second end surface 611 defines a second groove 71 , and the second groove 71 penetrates the second peeling film 40 .

The first end face 601 forms a first overflow area A on the first insulating layer 101 around the projected area of the first insulating layer 101 along the thickness direction of the first circuit substrate 10 , and the first groove 70 is located in the first overflow area A; the second end surface 611 forms a second The overflow area B, the second groove 71 is located in the second overflow area B. In this embodiment, only part of the first insulating layer 101 and part of the second insulating layer 201 are removed by laser drilling in the first overflow region A and the second overflow region B, thereby forming a first recess. For the groove 70 and the second groove 71, the material of the first insulating layer 101 drilled by laser is single, the process is simple, the timeliness is good, the requirements for alignment are low, and the requirements for laser drilling equipment are low.

Referring to Fig. 4 to Fig. 8, the shape, opening size, depth, arrangement and spacing between the first groove 70 and the second groove 71 in the present invention can be adjusted according to actual needs. specific design.

Referring to FIG. 4 and FIG. 5 , in this embodiment, the first groove 70 may be an annular groove, and the first groove 70 surrounds the first conductive paste block 60 . The second groove 71 may be an annular groove, and the second groove 71 surrounds the second conductive paste block 61 .

Please refer to FIG. 4 and FIG. 5 again. In this embodiment, the number of the first grooves 70 is multiple, the multiple first grooves 70 are arranged concentrically, and the depth of the multiple first grooves 70 is decrease successively along the direction away from the first end surface 601 . The number of the second grooves 71 can be multiple, the multiple second grooves 71 are arranged concentrically, and the depths of the multiple second grooves 71 decrease sequentially along the direction away from the second end surface 611 .

Please refer to FIG. 6 , in another embodiment, the number of the first grooves 70 is multiple, the multiple first grooves 70 are arranged concentrically, and the depth of the multiple first grooves 70 is along the The direction of the first end surface 601 increases sequentially. The number of the second grooves 71 can be multiple, the multiple second grooves 71 are arranged concentrically, and the depths of the multiple second grooves 71 increase sequentially along the direction away from the second end surface 611 . It can be understood that the first grooves 70 of different depths can also be arranged irregularly, the second grooves 71 of different depths can also be arranged irregularly, and the distance between two adjacent first grooves 70 And the distance between the second grooves 71 can be designed according to actual needs.

Please refer to FIG. 7 and FIG. 8 , in yet another embodiment, the number of the first grooves 72 is multiple, and the cross section of each of the first grooves 72 can be at least one of rectangle, circle and trapezoid. One, a plurality of first grooves 72 may be scattered in the first overflow area A, and the plurality of first grooves 72 are arranged around the first conductive paste block 60 . In this embodiment, the number of the second grooves 73 can also be multiple, and the cross-section of each of the second grooves 73 can be at least one of rectangle, circle and trapezoid. Grooves 73 may be scattered in the second overflow area B, and a plurality of second grooves 73 are arranged around the second conductive paste block 61 . In this embodiment, the first groove 72 and the second groove 73 are designed as smaller grooves, and there is no special requirement on the size and shape of the grooves, which requires low precision and is easy to form.

Step S6, please refer to FIG. 9 , remove the first release film 30 and the second release film 40 respectively, so that the first end surface 601 and the second end surface 611 respectively protrude from the first insulating layer 101 and the second insulating layer 201 to obtain the first circuit board 80 and the second circuit board 81 .

Step S7, stacking at least one first circuit board 80 and at least one second circuit board 81 to obtain an intermediate body (not shown).

In this embodiment, one first circuit board 80 , two second circuit boards 81 and one first circuit board 80 are stacked in sequence. Specifically, the first end surface 601 of one of the first circuit boards 80 is in one-to-one correspondence with the second end surface 611 of one of the second circuit boards 81, and the other first circuit board The first end surface 601 in the circuit board 80 is in one-to-one correspondence with the connection pad 2021 in the other second circuit board 81 .

Step S8, please refer to FIG. 10 , pressing the intermediate body so that the first conductive paste block 60 and the second conductive paste block 61 are filled in the first groove 70 and the second concave hole respectively. In the groove 71, wherein the first conductive paste block 60 located in the first blind hole forms a first conductive part 90, and the first conductive paste block 60 located in the first groove 70 forms a first overflow part 91, the second conductive paste block 61 located in the second blind hole forms a second conductive part 92, and the second conductive paste block 61 located in the second groove 71 forms a second overflow part 93, Thus, the multilayer circuit board 100 is obtained.

In this embodiment, after the pressing step, the part of the first conductive paste 60 that protrudes from the first insulating layer 101 and the part of the second conductive paste that protrudes from the second insulating layer 201 The block 61 is pressed and filled in the first groove 70 and the second groove 71 respectively, wherein the first conductive part 90 located in the first blind hole and the first conductive part 90 located in the first groove 70 The first overflow portion 91 in the second blind hole is connected to the second conductive portion 92 in the second blind hole and the second overflow portion 93 in the second groove 71 is connected.

In this embodiment, the first conductive part 90 in one of the first circuit boards 80 and the second conductive part 92 in one of the second circuit boards 81 are bonded to each other to electrically connect the first The conductive circuit layer 102 and the second conductive circuit layer 202, the second conductive part 92 in the other second circuit board 81 and the connection pad 2021 of one of the second conductive circuit layers 202 are connected to each other. bonding to electrically connect the two second conductive circuit layers 202, the first conductive part 90 in the other first circuit board 80 and the connection pad of the other second conductive circuit layer 202 2021 are bonded to each other to electrically connect the first conductive circuit layer 102 and the second conductive circuit layer 202 .

Please refer to FIG. 10 , and refer to FIG. 3 . In this embodiment, the radius r of the first end surface 601 is approximately equal to the radius r of the first blind hole 50 , which is approximately 100 microns. The first conductive paste block 60 The thickness H of the portion protruding from the first insulating layer 101 is equal to the thickness of PET, approximately 25 μm. The structural dimensions of the second blind hole 51 and the second conductive paste block 61 are substantially the same as those of the first blind hole 50 and the first conductive paste block 60 . Therefore, the volume V of the portion of the first conductive paste block 60 protruding from the first insulating layer 101 is approximately equal to the volume V of the portion of the second conductive paste block 61 protruding from the second insulating layer 201 , V=thickness of PET*area of the first end surface 601 or the second end surface 611=25 μm*3.14*100 μm*100 μm =785000 μm ³ . When the first conductive paste block 60 and the second conductive paste block 61 are stacked and pressed together, the total volume V total of the protruding copper paste: 2*V=2*785000=1570000μm ³ , assuming that there is no first groove 70 and the second groove 70 When the second groove is 71, the thickness of the overflow copper paste is 8~10μm. At this time, the overflow range of copper paste is R overflow, then Vtotal=3.14*R overflow ² , it can be deduced that the copper paste overflow range is about 707μm, and the copper paste overflow range is about 707μm. The maximum distance between the edge of the paste overflow and the edge of the blind hole is about 607 μm. Within this range, the overflowed copper paste is easily connected to the surrounding lines to cause a short circuit, or the overflowed copper paste forms a capacitor with the upper and lower copper layers.

The present invention makes a first groove 70 and a second groove 71 around the first blind hole 50 and the second blind hole 51 respectively, when the first circuit board 80 and the second circuit board 81 are in the pressing process In this process, the first conductive paste block 60 protruding from the first insulating layer 101 and the second conductive paste block 61 protruding from the second insulating layer 201 are overflow-filled into the first groove 70 and the second groove 71 respectively, It can avoid the phenomenon that the overflow area of conductive paste is too large to connect with the surrounding lines to cause short circuit or the phenomenon that the overflowed copper paste forms capacitance with the upper and lower copper layers.

Referring to FIG. 10 , an embodiment of the present invention also provides a multilayer circuit board 100 , the multilayer circuit board 100 includes at least one first circuit board 80 and at least one second circuit board 81 . The first circuit board 80 includes a stacked first insulating layer 101 and a first conductive circuit layer 102, and the first insulating layer 101 is provided with a first blind hole 50 and surrounding the first blind hole 50. At least one first groove 70, the first blind hole 50 is provided with a first conductive part 90, the first groove 70 is provided with a first overflow part 91, the first conductive part 90 and the The first conductive circuit layer 102 is electrically connected. The second circuit board 81 includes a stacked second insulating layer 201 and a second conductive circuit layer 202, and the second insulating layer 201 is provided with a second blind hole 51 and a hole around the second blind hole 51. At least one second groove 71, the second blind hole 51 is provided with a second conductive part 92, the second groove 71 is provided with a second overflow part 93, the second conductive part 92 and the The second conductive circuit layer 202 is electrically connected.

In this embodiment, the material of the first insulating layer 101 can be selected from epoxy resin (epoxy resin), prepreg (Prepreg, PP), BT resin, polyphenylene oxide (Polyphenylene Oxide, PPO), polyimide ( Polyimide, PI), polyethylene terephthalate (Polyethylene Terephthalate, PET) and polyethylene naphthalate (Polyethylene Naphthalate, PEN) and other resins. In this embodiment, the material of the first insulating layer 101 is polypropylene.

In this embodiment, the material of the second insulating layer 201 can be selected from epoxy resin (epoxy resin), prepreg (Prepreg, PP), BT resin, polyphenylene oxide (Polyphenylene Oxide, PPO), polyimide ( Polyimide, PI), polyethylene terephthalate (Polyethylene Terephthalate, PET) and polyethylene naphthalate (Polyethylene Naphthalate, PEN) and other resins. In this embodiment, the material of the first insulating layer 101 is polypropylene.

In this implementation manner, the thickness T of the first insulating layer 101 and the second insulating layer 201 is both 5-150 microns.

In this embodiment, the diameter of the first blind hole 50 gradually decreases from the first release film 30 to the first insulating layer 101, and the diameter of the second blind hole 51 decreases from the second The direction from the peeling film 40 to the second insulating layer 201 gradually decreases.

Referring to Fig. 4 to Fig. 8, the shape, opening size, depth, arrangement and spacing between the first groove 70 and the second groove 71 in the present invention can be adjusted according to actual needs. specific design.

Referring to FIG. 4 and FIG. 5 , in this embodiment, the first groove 70 may be an annular groove, and the first groove 70 surrounds the first blind hole 50 . The second groove 71 may be an annular groove, and the second groove 71 surrounds the second blind hole 51 .

Please refer to FIG. 4 and FIG. 5 again. In this embodiment, the number of the first grooves 70 is multiple, the multiple first grooves 70 are arranged concentrically, and the depth of the multiple first grooves 70 is It decreases successively along the direction away from the first blind hole 50 . The number of the second grooves 71 can be multiple, the multiple second grooves 71 are arranged concentrically, and the depths of the multiple second grooves 71 decrease successively along the direction away from the second blind hole 51. small.

Please refer to FIG. 6 , in another embodiment, the number of the first grooves 70 is multiple, the multiple first grooves 70 are arranged concentrically, and the depth of the multiple first grooves 70 is along the The directions of the first blind holes 50 increase sequentially. The number of the second grooves 71 can be multiple, the multiple second grooves 71 are arranged concentrically, and the depths of the multiple second grooves 71 increase sequentially along the direction away from the second blind hole 51. big. It can be understood that the first grooves 70 of different depths can also be arranged irregularly, the second grooves 71 of different depths can also be arranged irregularly, and the distance between two adjacent first grooves 70 And the distance between the second grooves 71 can be designed according to actual needs.

Please refer to FIG. 7 and FIG. 8 , in yet another embodiment, the number of the first grooves 72 is multiple, and the cross section of each of the first grooves 72 can be at least one of rectangle, circle and trapezoid. One, a plurality of first grooves 72 may be scattered around the first blind hole 50 , and the plurality of first grooves 72 are arranged around the first blind hole 50 . In this embodiment, the number of the second grooves 73 can also be multiple, and the cross-section of each of the second grooves 73 can be at least one of rectangle, circle and trapezoid. Grooves 73 may be scattered in the second blind hole 51 , and a plurality of second grooves 73 are arranged around the second blind hole 51 . In this embodiment, the first groove 72 and the second groove 73 are designed as smaller grooves, and there is no special requirement on the size and shape of the grooves, which requires low precision and is easy to form.

In this embodiment, the second conductive circuit layer 202 includes a plurality of connection pads 2021 .

In this embodiment, the first circuit board 80 has two layers, the number of the second circuit board 81 is two, and the first conductive part 90 in one of the first circuit boards 80 is connected with one of the first circuit boards 80. The second conductive part 92 in the second circuit board 81 is bonded to each other to electrically connect the first conductive circuit layer 102 and the second conductive circuit layer 202, and all the second conductive part 92 in the second circuit board 81 The second conductive part 92 is bonded to the connection pad 2021 of one of the second conductive circuit layers 202 to electrically connect the two second conductive circuit layers 202, and the other of the first circuit board 80 The first conductive portion 90 of the second conductive circuit layer 202 is bonded to the connection pad 2021 of the other second conductive circuit layer 202 to electrically connect the first conductive circuit layer 102 and the second conductive circuit layer 202 .

Please refer to FIG. 11 , another embodiment of the present invention also provides a multilayer circuit board 200, the first circuit board 80 in the multilayer circuit board 200 also includes a first connecting portion 94, the first conductive portion 90 and the first An overflow portion 91 is connected via the first connection portion 94 . The second circuit board 81 further includes a second connection portion 95 , and the second conductive portion 92 is connected to the second overflow portion 93 through a second connection portion 94 .

To sum up, the method for preparing a multilayer circuit board provided by the present invention is provided with a first groove 70 and a second groove 71 around the first blind hole 50 and the second blind hole 51 respectively, when the first circuit board 80 and the second circuit board 81 in the pressing process, the first conductive paste block 60 protruding from the first insulating layer 101 and the second conductive paste block 61 protruding from the second insulating layer 201 are respectively overflow filled into the first In the groove 70 and the second groove 71, the first groove 70 and the second groove 71 can restrict the flow of the conductive paste, which can avoid the problem that the overflow area of the conductive paste is too large and connected with the peripheral circuit to cause a short circuit or the overflow of the copper paste and the The phenomenon that the upper and lower copper layers form a capacitor. Furthermore, the contact area between the first conductive paste block 60 and the first insulating layer 101 and the contact area between the second conductive paste block 61 and the second insulating layer 201 can be increased, thereby increasing the The adhesion between the first conductive paste block 60 and the first insulating layer 101 and the adhesion between the second conductive paste block 61 and the second insulating layer 201 reduce the 60 and the second conductive paste block 61 are affected by cold and heat treatment, thereby improving the reliability of the multilayer circuit board 100 .

100,200: multi-layer circuit board 10: The first circuit substrate 101: The first insulating layer 102: the first conductive line layer 20: Second circuit substrate 201: second insulating layer 202: the second conductive line layer 2021: Connection Pads 30: The first release film 40: Second release film 50: The first blind hole 51: Second blind hole 60: The first conductive paste block 601: the first end face 61: Second conductive paste block 611: second end face 70,72: first groove 71,73: second groove 80: The first circuit board 81: Second circuit board 90: The first conductive part 91: The first overflow part 92: the second conductive part 93: Second overflow part 94: The first connecting part 95: the second connecting part A: First overflow area B: Second overflow area

FIG. 1 is a schematic structural view after forming a first peeling film and a second peeling film on a first circuit substrate and a second circuit substrate respectively according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of first blind holes and second blind holes respectively opened in the first circuit substrate and the second circuit substrate shown in FIG. 1 .

FIG. 3 is a schematic structural view of filling conductive paste in the first blind hole and the second blind hole shown in FIG. 2 to form a first conductive paste block and a second conductive paste block respectively.

FIG. 4 is a schematic structural view after forming a first groove and a second groove on the first insulating layer and the second insulating layer shown in FIG. 3 .

Fig. 5 is a schematic structural diagram of a first blind hole and a first groove provided by an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a first groove and a second groove provided by another embodiment of the present invention.

7 and 8 are structural schematic diagrams of the first groove and the second groove provided in another embodiment.

FIG. 9 is a schematic structural diagram after the first peeling film and the second peeling film shown in FIG. 4 are respectively removed.

FIG. 10 is a schematic structural view of a multilayer circuit board obtained by laminating and pressing the first circuit board and the second circuit board shown in FIG. 9 .

FIG. 11 is a schematic structural diagram of a multilayer circuit board provided by another embodiment of the present invention.

100: multilayer circuit board

101: The first insulating layer

102: the first conductive line layer

201: second insulating layer

202: the second conductive line layer

2021: Connection Pads

50: The first blind hole

51: Second blind hole

70: first groove

71: Second groove

80: The first circuit board

81: Second circuit board

90: The first conductive part

91: The first overflow part

92: the second conductive part

93: Second overflow part

Claims (11)

A method of manufacturing a multilayer circuit board, comprising: At least one first circuit board is provided, the first circuit board includes a stacked first insulating layer and a first conductive circuit layer, the first insulating layer is provided with a first blind hole and a At least one first groove around the first blind hole, a first conductive paste block electrically connected to the first conductive circuit layer is provided in the first blind hole, and the first conductive paste block protrudes out of the first Insulation; At least one second circuit board is provided, the second circuit board includes a stacked second insulating layer and a second conductive circuit layer, a second blind hole is provided in the second insulating layer and a second blind hole is located in the second blind hole At least one second groove around the second blind hole, a second conductive paste block electrically connected to the second conductive circuit layer is provided in the second blind hole, and the second conductive paste block protrudes out of the second Insulation; stacking at least one of the first circuit board and at least one of the second circuit board to obtain an intermediate body; and Pressing the intermediate body so that the first conductive paste block and the second conductive paste block are respectively filled in the first groove and the second groove, wherein the first blind The first conductive paste block in the hole forms a first conductive portion, the first conductive paste block in the first groove forms a first overflow portion, and the second conductive paste block in the second blind hole forms a first conductive portion. The paste block forms the second conductive portion, and the second conductive paste block located in the second groove forms the second overflow portion, thereby obtaining the multilayer circuit board. The method for manufacturing a multilayer circuit board as claimed in item 1, wherein the making of the first circuit board includes: A first circuit substrate is provided, the first circuit substrate includes the first insulating layer and the first conductive circuit layer stacked; forming a first release film on the first insulating layer; At least one first blind hole is opened through the first insulating layer, the first blind hole also passes through the first peeling film, and the diameter of the first blind hole is from the first peeling film to the The direction of the first insulating layer gradually decreases; Filling conductive paste into each of the first blind holes to obtain the first conductive paste block, wherein the first conductive paste block includes a first end surface away from the first conductive circuit layer; At least one first groove is formed in the first insulating layer around the first end surface, and the first groove penetrates the first release film; and The first peeling film is removed, so that the first end surface protrudes from the first insulating layer, so as to obtain the first circuit board. The method for manufacturing a multilayer circuit board as claimed in item 1, wherein the making of the second circuit board includes: A second circuit substrate is provided, the second circuit substrate includes the second insulating layer and the second conductive circuit layer stacked; forming a second release film on the second insulating layer; At least one second blind hole is opened through the second insulating layer, the second blind hole also passes through the second peeling film, and the diameter of the second blind hole is from the second peeling film to the The direction of the second insulating layer gradually decreases; Filling conductive paste into each of the second blind holes to obtain the second conductive paste block, wherein the second conductive paste block includes a second end surface away from the second conductive circuit layer; At least one second groove is formed in the second insulating layer around the second end surface, and the second groove penetrates the second release film; and The second peeling film is removed, so that the second end surface protrudes from the second insulating layer, so as to obtain the second circuit board. The method for manufacturing a multilayer circuit board according to claim 1, wherein the first groove is an annular groove, and the first groove surrounds the first conductive paste block; and/or The second groove is an annular groove, and the second groove surrounds the second conductive paste block. The method for manufacturing a multilayer circuit board according to claim 4, wherein the number of the first grooves is multiple, the multiple first grooves are arranged concentrically, and the depth of the multiple first grooves is along the The direction away from the first blind hole increases or decreases sequentially; and/or The number of the second grooves is multiple, the multiple second grooves are arranged concentrically, and the depths of the multiple second grooves increase or decrease sequentially along the direction away from the second blind hole . The method for manufacturing a multilayer circuit board according to claim 1, wherein the number of the first grooves is multiple, and the cross-section of each of the first grooves is at least one of rectangle, circle and trapezoid ;and / or There are multiple second grooves, and the cross-section of each second groove is at least one of rectangle, circle and trapezoid. The method for manufacturing a multilayer circuit board according to Claim 1, wherein, after the pressing step, both the first conductive paste block and the second conductive paste block are trapezoidal. A multilayer circuit board, including: At least one first circuit board, the first circuit board includes a stacked first insulating layer and a first conductive circuit layer, the first insulating layer is provided with a first blind hole and is located around the first blind hole at least one first groove, the first blind hole is provided with a first conductive part, the first groove is provided with a first overflow part, the first conductive part and the first conductive circuit layer electrical connection; At least one second circuit board, the second circuit board includes a stacked second insulating layer and a second conductive circuit layer, the second insulating layer is provided with a second blind hole and is located around the second blind hole at least one second groove, the second blind hole is provided with a second conductive part, the second groove is provided with a second overflow part, the second conductive part and the second conductive circuit layer electrical connection. The multilayer circuit board according to claim 8, wherein the first groove is an annular groove, and the first groove surrounds the first conductive paste block; and/or The second groove is an annular groove, and the second groove surrounds the second conductive paste block. The multilayer circuit board according to claim 9, wherein the number of the first grooves is multiple, the multiple first grooves are arranged concentrically, and the depth of the multiple first grooves is along the The direction of the first blind hole increases or decreases sequentially; and/or The number of the second grooves is multiple, the multiple second grooves are arranged concentrically, and the depths of the multiple second grooves increase or decrease sequentially along the direction away from the second blind hole . The multilayer circuit board according to claim 8, wherein the number of the first grooves is multiple, and the cross-section of each of the first grooves is at least one of rectangle, circle and trapezoid; and/ or There are multiple second grooves, and the cross-section of each second groove is at least one of rectangle, circle and trapezoid.

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