TWI608779B - Multilayer circuit board with high density interconnects and method of manufacturing the same - Google Patents

Description

High-density interconnect multilayer circuit board and manufacturing method thereof

The present invention relates to a multilayer board and a bonding method thereof, and more particularly to a high-density interconnection multilayer circuit board and a method of fabricating the same.

Printed circuit board is one of the indispensable components in many electronic products. Its function is to provide electronic signal transmission between different electronic components. With the advancement of printed circuit board (PCB) and electronic component manufacturing technology, Printed circuit boards and electronic components are also designed to be oriented in a small size to meet the current miniaturization of electronic products. However, while the volume or thickness of the printed circuit board is reduced, the attendant disadvantage is that the wiring area available on the printed circuit board is relatively reduced, and the layout design of the multilayer printed circuit board is correspondingly proposed so as not to increase the printing. Increase the area of the wiring under the premise of the board size.

In general, the vertical interconnection structure of a printed circuit board is generally manufactured by a high density interconnection (HDI) method, that is, a layer is added one by one, and a blind hole is filled by a laser. Hole plating and lamination processes are used to complete the vertical interconnections in order to form denser line connections with the same or smaller volume or thickness. In addition, there is a more special practice. Taking China Patent No. 200929495 as an example, it discloses a method for producing a high-interconnect density multilayer circuit, which mainly forms a through hole on the adhesive sheet, and then The via hole is filled with a conductive paste, and then the upper and lower layers of the polymer dielectric material carrying the high-density circuit are respectively attached to the upper and lower sides of the multilayer circuit core by the adhesive sheet. However, this method capacity It is easy to cause void defects due to the shallow plug of the conductive material, or the upper and lower interconnect failures due to the resin pressing the conductive plug.

In view of the deficiencies of the prior art, the main object of the present invention is to provide a method for manufacturing a high-density interconnected multilayer circuit board capable of effectively preventing connection failure between an upper layer and a lower layer circuit board, and a high-density mutual interface manufactured by the method. Connect multiple layers of boards.

A preferred embodiment of the present invention provides a method of fabricating a high-density interconnected multilayer circuit board, comprising the steps of: providing a pre-formed first multi-layer circuit substrate and a second multi-layer circuit substrate, wherein the first plurality The layer circuit substrate has a first bonding surface, and the first bonding surface is provided with a first contact pad array; a conductive bump is formed on each of the first contact pads in the first contact pad array, and Forming a glue layer on the first joint surface, wherein a plurality of the conductive bumps are exposed from the glue layer; a conductive composite material is filled in a gap between each of the conductive bumps and the glue layer; The second multilayer circuit substrate is pressed together with the first multilayer circuit substrate through the glue layer, wherein the second multilayer circuit substrate is covered by the plurality of the conductive bumps and the plurality of The conductive composite material is electrically connected to the first multilayer circuit substrate.

Another preferred embodiment of the present invention provides a high density interconnect multilayer circuit board including a first multilayer circuit substrate, a glue layer, a plurality of conductive composite materials, and a second multilayer circuit substrate. The first multilayer circuit substrate has a first bonding surface, the first bonding surface is provided with a first contact pad array, and each of the first contact pad arrays is provided with a conductive bump a plurality of the conductive bumps are exposed from the glue layer a gap between the conductive bump and the glue layer; and the second multilayer circuit substrate is disposed on the glue layer, and the second multilayer circuit substrate is covered by the plurality of conductive bumps and Multiple The conductive composite material is electrically connected to the first multilayer circuit substrate.

The present invention has at least the following technical effects: the present invention firstly forms a bump array including a plurality of conductive bumps on a first multilayer circuit substrate, and then forms a glue layer to surround it, and then in each conductive bump The gap of the glue layer is filled with a conductive composite material to fill the gap, and finally the flow design of the first and second multilayer circuit substrates is bonded through the glue layer, thereby avoiding formation between the contact pads of the upper layer and the lower circuit substrate. Void defect.

Furthermore, since each of the contact pads of the upper circuit substrate and the corresponding contact pads on the lower circuit substrate have a transmission path formed by conductive bumps coated with a conductive composite material, and each has The conductive bumps coated by the conductive composite are completely dense with the corresponding inner edges of the through holes, thereby increasing the reliability and quality of signal transmission.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings.

S100-S106‧‧‧Steps

M‧‧‧High Density Interconnect Multilayer Board

1‧‧‧First multilayer circuit board

11‧‧‧First joint

12‧‧‧First contact pad array

121‧‧‧First contact pad

122‧‧‧ outside diameter

13‧‧‧Interlayer insulation

14‧‧‧through-type conductive structure

2‧‧‧Second multilayer circuit board

21‧‧‧Second joint

22‧‧‧Second contact pad array

221‧‧‧Second contact pad

23‧‧‧Interlayer insulation

24‧‧‧through-type conductive structure

3‧‧‧Electrical bumps

30‧‧‧ outside diameter

31‧‧‧ top surface

32‧‧‧ bottom

33‧‧‧ ring side

4‧‧‧Glued layer

41‧‧‧ openings

410‧‧‧ caliber

42‧‧‧through holes

5‧‧‧ Conductive composite materials

1 is a flow chart showing a method of manufacturing a high-density interconnection multilayer circuit board according to a preferred embodiment of the present invention.

2 is a schematic structural view of a first multilayer circuit substrate and a first multilayer circuit substrate in a high-density interconnection multilayer circuit board of the present invention.

3 is a partially exploded perspective view of the high density interconnect multilayer circuit board of the present invention.

Figure 4 is a partial enlarged view of a portion A of Figure 3.

Fig. 5 is a schematic view showing the combination of the high-density interconnection multilayer circuit board of the present invention.

Figure 6 is a partial enlarged view of a portion B of Figure 5.

The technical content disclosed by the present invention is mainly related to an innovative bonding method of a high-density interconnected multilayer circuit board, and a high-density interconnection made by using the bonding method. Multi-layer circuit board. The invention is characterized in that the upper circuit substrate and the lower circuit substrate are separately fabricated, and then the conductive bump array is formed on the contact pad array of the upper or lower circuit substrate, and then a glue layer is formed around the conductive bump array, and A conductive bump and a gap of the bonding layer are filled with the conductive composite material to fill the gap, and finally the upper layer and the lower circuit substrate are combined by the bonding layer; in this way, the contact pad of the upper layer and the lower circuit substrate can be effectively improved. A cavity defect is formed, which causes a problem of failure of the upper and lower interconnections, and a high-frequency signal transmission structure in which the conductive composite material completely encapsulates the conductive bump can be formed between the contact pads of the upper layer and the lower circuit substrate to increase the reliability of signal transmission. Degree and quality.

Various illustrative embodiments are described more fully hereinafter with reference to the accompanying drawings. However, the inventive concept may be embodied in many different forms and should not be construed as being limited to the illustrative embodiments set forth herein. Rather, these exemplary embodiments are provided so that this invention will be in the In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Similar numbers always indicate similar components.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements or signals and the like, such elements or signals are not limited by the terms. These terms are used to distinguish one element from another, or a signal and another. In addition, as used herein, the term "or" may include all combinations of any one or more of the associated listed items.

Please refer to FIG. 1 , which is a schematic flow chart of a method for manufacturing a high-density interconnection multilayer circuit board according to a preferred embodiment of the present invention. Referring to FIG. 2 to FIG. 6 , the manufacturing method of the high-density interconnection multilayer circuit board first performs step S100 : providing the first multilayer circuit substrate 1 and the second multilayer circuit substrate 2 which are prepared in advance. The first thing to note is that due to the limited processing capability, for example, the drilling ability of the existing burs is insufficient. The industry often adopts the process technology of “making the upper and lower multi-layer boards separately and then laminating” to increase the printed circuit board. The number of layers. In this embodiment, the first multilayer circuit substrate 1 has a first bonding surface 11 and The first bonding surface 11 is provided with a first contact pad array 12; the second multilayer circuit substrate 2 has a second bonding surface 21, and the second bonding surface 21 is provided with a second corresponding to the first contact pad array 12. Contact pad array 22.

In practice, the arrangement of the first contact pad array 12 and the second contact pad array 22 may be changed according to the trend of fine pitch and smaller component size, which is not limited by the present invention; The number, shape, and size ratio of the first contact pads 121 of the first contact pad array 12 and the second contact pads 221 of the second contact pad array 22 may also be adjusted according to actual use requirements, and the detailed layout may be More complicated.

Further, the first multilayer circuit substrate 1 (the following layer circuit substrate) mainly includes a plurality of interlayer insulating layers 13 and a plurality of wiring layers (including internal interconnection lines, not shown) and a plurality of through-through layers that are alternately stacked. Conductive structure 14, well-known in the art, should understand the process technology for forming the interlayer insulating layer 13, the straight-through conductive structure 14 and the wiring layer, for example, by using lithography and etching, mechanical drilling or laser drilling Forming a through hole, forming a metal layer of the hole wall in the through hole, filling the remaining space with an insulating material to form a straight-through conductive structure 14, and forming a wiring layer by a process such as metal deposition, lithography, etching, etc.; There are many changes and options, so I won’t go into details here.

Similarly, the second multilayer circuit substrate 2 (the upper layer circuit substrate) mainly includes a plurality of interlayer insulating layers 23 and a plurality of wiring layers (including internal interconnection lines, not shown) and a plurality of straight-through conductive layers which are alternately stacked. Structure 24, those skilled in the art should understand the related process technology for forming the interlayer insulating layer 23, the straight-through conductive structure 24 and the wiring layer, and will not be described here. It should be noted that, in FIG. 2, the structures of the first multilayer circuit substrate 1 and the second multilayer circuit substrate 2 are of a symmetrical type, that is, the interlayer insulating layer 13 and the cloth included in the first multilayer circuit substrate 1. The number of layers of the line layer is the same as the number of layers of the interlayer insulating layer 23 and the wiring layer included in the second multilayer circuit substrate 2; however, for other embodiments of the embodiment, the first multilayer circuit substrate 1 and the first The structure of the two-layer circuit substrate 2 may also be an asymmetrical type, that is, the number of layers of the interlayer insulating layer 13 and the wiring layer included in the first multilayer circuit substrate 1, and the number of layers included in the second multilayer circuit substrate 2. Floor The number of layers of the interlayer insulating layer 23 and the wiring layer is different. Therefore, FIG. 2 is for reference and description only and is not intended to limit the invention.

Then, a step S102 is performed to form a conductive bump 3 on each of the first contact pads 121 of the first contact pad array 12, and a glue layer 4 is formed on the first bonding surface 11, wherein the plurality of conductive bumps 3 is exposed from the glue layer 4, respectively. The conductive bump 3 can serve as an external electrical contact of the first multilayer circuit substrate 1, and the material thereof can be a single metal or a multi-element alloy (such as copper or copper alloy); the bonding layer 4 is used to bond the first multilayer circuit substrate 1 The material is bonded to the second multilayer circuit substrate 2, and the material thereof may be a polypropylene resin composition containing glass fibers. In practice, the conductive bumps 3 can be formed by printing, sputtering coating, electro plating, or chemical vapor deposition, and lithography and etching processes, and the bonding layer 4 is It can be formed by pressing, but the invention is not limited thereto.

In this embodiment, the thickness of the glue layer 4 when formed is greater than the height of the conductive bumps 3, that is, the conductive bumps 3 are covered by the glue layer 4. In order to expose the conductive bumps 3 from the glue layer 4, a plurality of openings 41 are formed on the glue layer 4 by laser processing. However, the processing method of the openings 41 is not particularly limited thereto, and the operator can according to actual needs. The opening 41 is formed by a lithography and etching process; preferably, the opening 410 of each opening 41 is larger than the outer diameter 30 of the top of the corresponding conductive bump 3 and smaller than the corresponding first contact pad 121. Trail 122.

Then, step S104 is performed: a conductive composite material 5 is filled in the gap G between each of the conductive bumps 3 and the bonding layer 4. In practice, the conductive composite material 5 can be formed by printing, but the manner of molding the conductive composite material 5 is not particularly limited thereto. In this embodiment, each conductive composite material 5 may be composed of a copper-tin alloy, a copper paste or a silver paste, wherein a copper-tin alloy is preferably used. Specifically, the copper-tin alloy may include copper and tin. And at least one metal selected from the group consisting of ruthenium, indium, zinc, manganese, chromium, nickel, ruthenium, osmium, platinum, magnesium, aluminum, and zirconium.

It should be noted that, in step S102, “a bump array including a plurality of conductive bumps 3 is formed first, and then a glue layer 4 is formed to closely surround the cover bump array, and then The process of forming a plurality of openings 41 in the glue layer 4 by laser processing to expose the conductive bumps 3 is designed. Therefore, the glue layer 4 has a plurality of through holes 42 and the plurality of conductive bumps 3 are respectively located in a plurality of through holes. In the hole 42, the top surface 31 and the ring side surface 33 of each of the conductive bumps 3 are not in contact with the inner edges of the corresponding through holes 42, and a gap G is formed between each other; therefore, in step S104, further A gap G is filled with a conductive composite material 5 to fill the gap G, that is, the remaining space in the through hole 42 is filled.

Furthermore, although the glue layer 4 still has fluidity before it is completely cured, since the plurality of conductive bumps 3 are pre-configured on the first joint surface 11 of the first multilayer circuit substrate 1, it can be used to block or The sliding of the bonding layer 4 relative to the first multilayer circuit substrate 1 is restricted, and the conductive bumps 3 coated with the conductive composite material 5 and the inner edges of the corresponding through holes 42 are completely dense without any void defects.

In addition, since the initially formed conductive composite material 5 has not been completely cured, after the step S104 is completed, the method for manufacturing the high-density interconnected multilayer circuit board further needs to perform a heat treatment step to completely cure the conductive composite material 5; Preferably, in order to ensure the bonding effect of the first and second multilayer circuit substrates 1, 2, only the glue layer 4 can be heated to semi-cured in the heat treatment step, so the temperature of the heat treatment must be smaller than the glass transfer of the material of the glue layer. Temperature to avoid transition of the glue layer.

Finally, step S106 is performed: the second multilayer circuit substrate 2 is pressed together with the first multilayer circuit substrate 1 through the glue layer 4, wherein the second multilayer circuit substrate 2 is covered by the plurality of conductive bumps 3 and The conductive composite material 5 is electrically connected to the first multilayer circuit substrate 1. In this embodiment, the glue layer 4 itself has adhesiveness, so the first and second multilayer circuit substrates 1 and 2 can be directly attached to the opposite surfaces of the glue layer 4 by hot pressing, and each of the first A contact pad 121 and the opposite second contact pad 221 are electrically connected to each other through a transmission path formed by the conductive bumps 3 coated with the conductive composite material 5.

Referring to FIG. 4 to FIG. 6 , after step S100 to step S106 is completed, a novel high-density interconnect multilayer circuit board M can be fabricated, which can be used as a post-package test or The interposer or the probe card PCB for the wafer level package test, however, the application field and use of the high-density interconnection multilayer circuit board M are not particularly limited thereto. As shown, the high-density interconnect multilayer circuit board M includes a first multilayer circuit substrate 1, a glue layer 4, a plurality of conductive composite materials 5, and a second multilayer circuit substrate 2. A first contact pad array 12 is disposed on the first bonding surface 11 of the first multilayer circuit substrate 1 , and each of the first contact pads 121 of the first contact pad array 12 is provided with a conductive bump 3; the bonding layer 4 Disposed on the first bonding surface 11 and surrounding the plurality of conductive bumps 3, wherein the plurality of conductive bumps 3 are exposed from the bonding layer 4; the plurality of conductive composite materials 5 are respectively filled in each of the conductive bumps 3 and the bonding layer 4. a gap G; a second multilayer circuit substrate 2 is disposed on the glue layer 4, and a second contact pad array 22 corresponding to the first contact pad array 12 is disposed on the second bonding surface 21 of the second multilayer circuit substrate 2, The second contact pad array 22 is electrically connected to the first contact pad array 12 by a plurality of conductive bumps 3 and a plurality of conductive composite materials 5.

Specifically, the glue layer 4 has a plurality of through holes 42 , and the plurality of conductive bumps 3 and the plurality of conductive composite materials 5 are respectively located in the plurality of through holes 42 , and the inner edge of each of the consistent holes 42 and the conductive composite material are provided The covered conductive bumps 3 are completely dense. Structurally, each of the conductive bumps 3 has a top surface 31, a bottom surface 32 corresponding to the top surface 31, and a ring side surface 33 between the top surface 31 and the bottom surface 32, at each first contact. Between the pad 121 and the corresponding second contact pad 221, a gap G exists between the conductive bump 3 and the inner edge of the through hole 42, and the conductive composite material 5 is just filled in the gap G; the bottom surface 32 of the conductive bump 3 is The first contact pads 121 are connected, and the conductive composite material 5 is connected on the one hand to the top surface 31 and the ring side surface 33 of the conductive bump 3, and on the other hand to the second contact pad 221.

Incidentally, the structure of the conductive bump 3 and the through hole 42 may vary according to the process taken; in this embodiment, although the outer diameter 30 of the conductive bump 3 shown in FIG. 4 is the second contact pad The direction of the first contact pad 121 is gradually increased, that is, the conductive bump 3 is a trapezoidal trapezoid having a trapezoidal cross section, and the aperture (not labeled) of the through hole 42 is from the second contact pad 221 to the first contact pad 121. The direction of the hole is gradually reduced, that is, the through hole 42 is slightly funnel shaped, however, the invention is not limited thereto. For different implementations of this embodiment, the conductive bumps 3 can be of any geometric shape (such as a rectangular shape, a cylindrical shape, etc.), and the through holes 42 can be hollow cylindrical.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Therefore, equivalent technical changes made by the present invention and the contents of the drawings are included in the scope of the present invention.

M‧‧‧High Density Interconnect Multilayer Board

1‧‧‧First multilayer circuit board

12‧‧‧First contact pad array

121‧‧‧First contact pad

13‧‧‧Interlayer insulation

14‧‧‧through-type conductive structure

2‧‧‧Second multilayer circuit board

22‧‧‧Second contact pad array

221‧‧‧Second contact pad

23‧‧‧Interlayer insulation

24‧‧‧through-type conductive structure

3‧‧‧Electrical bumps

4‧‧‧Glued layer

5‧‧‧ Conductive composite materials

Claims (18)

A manufacturing method of a high-density interconnection multilayer circuit board, comprising the steps of: providing a first multilayer circuit substrate and a second multilayer circuit substrate prepared in advance, wherein the first multilayer circuit substrate has a first bonding surface, And forming a first contact pad array on the first bonding surface; forming a conductive bump on each of the first contact pads, and forming a glue on the first bonding surface; a layer, wherein a plurality of the conductive bumps are exposed from the glue layer; a conductive composite material is filled in a gap between each of the conductive bumps and the glue layer; and the second multilayer circuit substrate is transparent The bonding layer is press-fitted together with the first multilayer circuit substrate, wherein the second multilayer circuit substrate comprises a plurality of the conductive bumps and a plurality of the conductive composite materials and the first plurality The layer circuit substrate is electrically connected. The manufacturing method of the high-density interconnection multilayer circuit board of claim 1, wherein the step of forming the conductive bumps on each of the first contact pads in the first contact pad array further comprises utilizing The laser processing forms a plurality of openings on the glue layer such that a plurality of the conductive bumps are exposed to the plurality of openings, respectively. The manufacturing method of the high-density interconnection multilayer circuit board according to claim 2, wherein a diameter of each of the openings is larger than an outer diameter of a corresponding top of the conductive bumps, and is smaller than the corresponding first contact The inner diameter of the pad. The method for manufacturing a high-density interconnection multilayer circuit board according to claim 1, wherein in the step of filling the conductive composite material in a gap between each of the conductive bumps and the glue layer, each of the conductive composites The material is filled into the gap between the corresponding conductive bump and the glue layer by printing. A method of manufacturing a high-density interconnected multilayer circuit board according to claim 4, wherein each of said conductive composite materials is composed of a copper-tin alloy, a copper paste or a silver paste. A method of manufacturing a high-density interconnected multilayer circuit board according to claim 5, wherein The copper-tin alloy includes at least one of copper, tin, and antimony, indium, zinc, manganese, chromium, nickel, lanthanum, cerium, platinum, magnesium, aluminum, and zirconium. The method of manufacturing a high-density interconnection multilayer circuit board according to claim 1, wherein the step of filling the conductive composite material in a gap between each of the conductive bumps and the bonding layer and the second The step of bonding the layer circuit substrate through the bonding layer to the first multilayer circuit substrate further includes a heat treatment step to completely cure each of the conductive composite materials and to bond the bonding layer Semi-cured. The method of manufacturing a high-density interconnected multilayer circuit board according to claim 7, wherein the heat treatment has a temperature lower than a glass transition temperature of a material of the glue layer. The method of manufacturing the high-density interconnection multilayer circuit board of claim 1, wherein the second multilayer circuit substrate has a second bonding surface, and the second bonding surface is provided with a second contact pad array; In the step of pressing the second multilayer circuit substrate through the glue layer and the first multilayer circuit substrate, the second contact pad array comprises a plurality of the conductive bumps and a plurality of The conductive composite material is electrically connected to the first contact pad array of the first multilayer circuit substrate. A high-density interconnected multilayer circuit board comprising: a first multi-layer circuit substrate having a first bonding surface, the first bonding surface being provided with a first contact pad array, and Each of the first contact pads is provided with a conductive bump; a glue layer, the glue layer is disposed on the first joint surface and surrounds the plurality of the conductive bumps, wherein the plurality of The conductive bumps are exposed from the glue layer; a plurality of conductive composite materials, a plurality of the conductive composite materials respectively filling a gap between each of the conductive bumps and the glue layer; and a second multilayer circuit substrate, The second multilayer circuit substrate is disposed on the glue layer, and the second multilayer circuit substrate comprises a plurality of the conductive bumps and the plurality of the conductive composite materials and the first multilayer circuit The substrate is electrically connected. The high-density interconnection multilayer circuit board of claim 10, wherein the second multilayer circuit substrate has a second bonding surface, and the second bonding surface is provided with the first Contacting the second contact pad array corresponding to the array of pads, and the second contact pad array is formed by the plurality of the conductive bumps and the plurality of the conductive composite materials and the first multilayer circuit substrate A contact pad array is formed to be conductive. The high-density interconnection multilayer circuit board of claim 10, wherein the glue layer has a plurality of through holes, and the plurality of the conductive bumps and the plurality of the conductive composite materials are respectively located in the plurality of through holes . The high-density interconnected multilayer circuit board of claim 12, wherein each of the conductive bumps has a top surface, a bottom surface corresponding to the top surface, and a top surface and the bottom surface The bottom surface of each of the conductive bumps is connected to the corresponding first contact pads, and each of the conductive composite materials is connected to the corresponding second contact pads and the conductive bumps The top surface. The high-density interconnected multilayer circuit board of claim 12, wherein an aperture of each of the through holes is gradually reduced from a corresponding one of the second contact pads toward a corresponding one of the first contact pads. The high-density interconnect multilayer circuit board of claim 13, wherein each of the conductive composite materials is connected to a corresponding loop side of the conductive bump. The high-density interconnect multilayer circuit board of claim 10, wherein each of the conductive composite materials is a copper-tin alloy, a copper paste or a silver paste. The high-density interconnect multilayer circuit board of claim 16, wherein the copper-tin alloy comprises copper, tin and antimony, indium, zinc, manganese, chromium, nickel, lanthanum, cerium, platinum, magnesium, aluminum, and zirconium. At least one metal in the middle. The high-density interconnection multilayer circuit board of claim 10, wherein an outer diameter of each of the conductive bumps is gradually increased from a corresponding second contact pad toward a corresponding one of the first contact pads. .