TWI672078B - Multi-layer circuit board and manufacturing method thereof - Google Patents

Abstract

A multilayer circuit board includes a plurality of insulating bumps, a first conductor layer, and a second conductor layer. A plurality of insulating bumps are disposed between the first substrate and the second substrate, and the tops of the plurality of insulating bumps serve as circuit connection points. The first conductor layer is disposed on the first substrate and is connected to a circuit connection point. The second conductor layer is disposed on the second substrate and is connected to the circuit connection point.

Description

Multilayer circuit board and manufacturing method thereof

The invention relates to a circuit board, and in particular to a multilayer circuit board using a 3D printing technology and a manufacturing method thereof.

The circuit board is an indispensable key component in an electronic device, and is mainly responsible for signal transmission and connection between internal electronic components. Under the trend of electronic devices continuously pursuing lightness, thinness and shortness, the line width of the wires on circuit boards has also continued to shrink. Therefore, the industry is committed to researching how to break through process, material and other limiting factors to obtain low cost and high reliability. High-performance, high-density circuit boards.

In order to achieve a high-density circuit design and high-density circuit layer-to-layer interconnection, it is necessary to reduce the line use space occupied by vias in a general circuit board. Generally, the manufacturing method of the interlayer interconnection technology commonly used for high density interconnects (High Density Interconnection; HDI) is a free stack structure, which uses a laser drilling and metal filling process to complete the electrical connection between the circuit layers. This method has the disadvantages of complicated manufacturing process, high pollution post-treatment and low yield of finished products. In Buried Bump Interconnection Technology (B2it), a double-sided or multi-layer board is first produced, and conductive materials are printed on copper foil through multiple screen printing to form conical bumps, and then combined lamination is used. In the manufacturing process, after the insulating sheet is placed on the conductive bumps, the insulating layer plate is laminated on the copper foil by hot pressing, and the conductive bumps are penetrated through the insulating sheet, so that the prefabricated conductive bumps can be electrically connected between the circuit layers.

However, in the B2it process, because the conductive paste used for making bumps has high viscosity and low thixotropic index (TI), it is impossible to reach the design height when printing conductive materials only once. Repeating the process of printing and curing the conductive material 4 to 5 times can form conductive bumps with a designed height. In the process of bumps piercing the insulating layer to the superimposed layer, the conductive bumps are prone to skew, which will cause poor connection of the printed circuit board (PCB) and reduce the production yield.

The invention provides a multi-layer circuit board, which uses non-metallic materials (ceramic materials) to prefabricate bumps, which can obtain better material characteristics and avoid the skew of the bumps during the press-puncture process.

The invention provides a method for manufacturing a multilayer circuit, which uses 3D printing technology to print bumps with ceramic materials, and prints conductive lines on a substrate and bumps with 3D functional printing to make high-density multilayer circuits. board.

The multilayer circuit board of the present invention includes a first substrate, a plurality of insulating bumps, a first conductor layer, a second substrate, and a second conductor layer. The plurality of insulating bumps are disposed on the first substrate, and a material of the insulating bumps is a ceramic material. The first conductor layer is disposed on the first substrate, and a part of the first conductor layer is located on top of the plurality of insulating bumps. The second substrate is disposed on the first substrate and has a first conductor layer with a plurality of openings exposing the tops of the plurality of insulating bumps, respectively. The second conductor layer is disposed on the second substrate, and the second conductor layer is electrically connected to the first conductor layer on top of the plurality of insulating bumps.

In an embodiment of the present invention, the above-mentioned multilayer circuit board further includes a bonding adhesive layer. The adhesive layer is disposed between the first substrate and the second substrate.

According to an embodiment of the present invention, the first conductive layer includes a plurality of first conductive wires. The plurality of first wires include a first extension portion and a first connection portion. The first extension portion is disposed on the first substrate. The first connection portion is located on the top of the insulating bump.

In an embodiment of the present invention, the second conductor layer includes a plurality of second wires. The plurality of second wires include a second extension portion and a second connection portion. The second extension portion is disposed on the second substrate. The second connection portion is located on the top of the insulating bump.

In an embodiment of the present invention, the first substrate and the second substrate are made of an insulating material.

A multilayer circuit board of the present invention includes a plurality of insulating bumps, a first conductor layer, and a second conductor layer. A plurality of insulating bumps are disposed between the first substrate and the second substrate. The tops of the plurality of insulating bumps serve as circuit connection points, and the material of the insulating bumps is a ceramic material. The first conductor layer is disposed on the first substrate and is connected to a circuit connection point. The second conductor layer is disposed on the second substrate and is connected to the circuit connection point.

The method for manufacturing a multilayer circuit board of the present invention includes the following steps. A plurality of protruding bumps are formed on the first substrate. The plurality of protruding bumps include a 3D printing method, and the material of the protruding bumps is a ceramic material. A first conductor layer is formed on the first substrate, and a part of the first conductor layer is located on top of the plurality of insulating bumps. A bonding glue layer is formed on the second substrate. The first substrate and the second substrate are pressed together, and the insulating bump passes through the bonding adhesive layer and the second substrate, and the top is exposed. A second conductor layer is formed on the second substrate, and the second conductor layer is electrically connected to the first conductor layer on top of the plurality of insulating bumps. The first conductor layer and the second conductor layer are formed by using a 3D printing method.

In an embodiment of the present invention, after the method for manufacturing a multilayer circuit board described above uses a 3D printing method to form a plurality of insulating bumps, it further includes performing a sintering process.

In an embodiment of the present invention, after forming the adhesive layer on the second substrate and before pressing the first substrate and the second substrate, the method further includes forming a plurality of openings in the adhesive layer.

In an embodiment of the present invention, the above-mentioned laminating the first substrate and the second substrate includes performing a heat-bonding process.

Based on the above, the present invention uses 3D printing technology to print bumps with ceramic materials, and 3D functional printing to print conductive lines on plates and bumps to make high-density multilayer circuit boards. In addition to simplifying the process and effectively using materials, and because non-metallic materials are used to prefabricate the bumps, better material characteristics can be obtained, and the skew of the bumps in the press-puncture process can be avoided. In addition to printing conductive lines, which can effectively reduce material consumption, they can also provide a green manufacturing process and reduce environmental pollution.

In order to make the above features and advantages of the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

Please refer to FIG. 1A to FIG. 1G, which are schematic diagrams of a method for manufacturing a multilayer circuit board according to a preferred embodiment of the present invention.

Referring to FIG. 1A, a substrate 100 is first provided. The substrate 100 includes an insulating substrate, and a material thereof is, for example, a resin. Then, a plurality of insulating bumps 102 are formed on the substrate 100. The hardness of the insulating bump is, for example, greater than the hardness of silver, that is, the hardness of the insulating bump is, for example, greater than the Mohs hardness 2.7. The material of the insulating bump 102 includes a ceramic material, such as zirconia, alumina, silicon dioxide, titanium dioxide, silicon nitride, silicon carbide, or a combination thereof. The insulating bump 102 is formed by, for example, a 3D printing method, and a ceramic material powder is spray-printed into a bump shape by a 3D printing technology. In addition, after the plurality of insulating bumps 102 are formed by using the 3D printing technology, a sintering process may be performed to sinter the ceramic powder into a ceramic body. In one embodiment, the plurality of insulating bumps 102 includes a stencil printing method. In addition, the use of 3D printing technology can complete the production of the insulating bumps at one time, compared with those who are familiar with the use of stencil printing technology, it can save the cost of multiple re-copying processes to complete the insulating bumps.

Referring to FIG. 1B, a conductive layer 104 is formed on the substrate 100. A portion of the conductive layer 104 is located on top of the plurality of insulating bumps 102. The conductive layer 104 is formed by using a 3D printing method. A 3D printing technique is used to print a circuit pattern (conductor layer 104) of a conductive line on the substrate 100 and the plurality of insulating bumps 102. The material of the conductive layer 104 is, for example, gold, silver, copper, aluminum, or other metals. The conductor layer 104 includes a plurality of conductive lines, and the plurality of conductive lines are, for example, divided into an extension portion 104 a and a connection portion 104 b. The extension portion 104 a is disposed on the substrate 100, and the connection portion 104 b is located on the top of the insulating bump 102.

Referring to FIG. 1C, another substrate 106 is prepared, and a bonding adhesive layer 108 is formed on the substrate 106. The substrate 106 includes an insulating substrate, and a material thereof is, for example, a resin. The bonding adhesive layer 108 is, for example, a thermocompression bonding adhesive layer. The adhesive layer 108 is formed on the substrate 106 in a bonding manner, for example. In one embodiment, before or after the bonding adhesive layer 108 is adhered to the substrate 106, the bonding adhesive layer 108 is selectively formed to form a plurality of openings 110. In one embodiment, in the step of forming the plurality of openings 110 in the bonding adhesive layer 108, the openings can also be selectively formed on the substrate 106. A method of forming the plurality of openings 110 includes laser lithography. The plurality of openings 110 are formed corresponding to the plurality of insulating bumps 102 on the substrate 100, respectively. A plurality of openings are formed in the bonding adhesive layer 108, which can prevent the residual adhesive of the bonding adhesive layer 108 from overflowing when the substrate 100 and the substrate 106 are subsequently pressed.

Referring to FIG. 1D, the substrate 100 and the substrate 106 are pressed together, so that the plurality of insulating bumps 102 pierce the substrate 106 through the bonding adhesive layer 108, and the tops of the plurality of insulating bumps 102 with the conductive layer 104 formed are exposed. A method of bonding the substrate 100 and the substrate 106 is, for example, a hot pressing method. The substrate 106 (insulating layer board) and the bonding adhesive layer 108 are covered on the substrate 100 of the completed circuit by a hot pressing method, and the insulating bump 102 printed with the conductor circuit pattern (the conductor layer 104) is penetrated through the upper substrate 106 . That is, the insulating bump 102 passes through the bonding adhesive layer 108 and the substrate 106 and exposes the top.

Referring to FIG. 1E, a conductor layer 112 is formed on the substrate 106, and the conductor layer 112 is electrically connected to the conductor layer 104 on top of the plurality of insulating bumps 102. The conductive layer 112 is formed by using a 3D printing method. The conductor layer 112 is formed on the substrate 106 and the conductor layer 104 exposed by the substrate 106 by using a 3D printing technology. The material of the conductive layer 112 is, for example, gold, silver, copper, aluminum, or other metals. The conductive layer 112 includes a plurality of conductive lines, and the plurality of conductive lines are, for example, divided into an extension portion 112 a and a connection portion 112 b. The extending portion 112 a is disposed on the substrate 106, and the connecting portion 112 b is located on the top of the insulating bump 102.

Referring to FIG. 1F, a protective plate 114 is prepared, and a bonding adhesive layer 116 is formed on the protective plate 114. The protective plate 114 includes an insulating substrate, and a material thereof is, for example, resin. The bonding adhesive layer 116 is, for example, a thermocompression bonding adhesive layer. The bonding adhesive layer 116 is formed on the protective plate 114 by bonding, for example. After the bonding adhesive layer 116 is adhered to the protective plate 114, a plurality of contact openings 118 are further formed in the protective plate 114. A method of forming the plurality of contact openings 118 includes a laser perforation method.

Referring to FIG. 1G, the protective plate 114 is pressed onto the substrate 106, and the contact opening 118 exposes a part of the conductive layer 112 on the substrate 106. A method of pressing the protective plate 114 onto the substrate 106 is, for example, a hot pressing method.

In the above embodiment, the formation of a two-layer circuit board is taken as an example. Of course, the steps of forming an insulating bump, printing a conductive pattern, and pressing an insulating layer board can be repeated on the substrate, and then the protective board is pressed on On the substrate, two or more layers of circuit boards are formed.

2A and 2B are a schematic cross-sectional view and a three-dimensional structure view of a multilayer circuit board according to an embodiment of the present invention. In FIGS. 2A and 2B, the same components as those in FIGS. 1A to 1G are given the same reference numerals, and detailed descriptions thereof are omitted.

2A and 2B are a schematic cross-sectional view and a three-dimensional structure view of a multilayer circuit board according to an embodiment of the present invention.

As shown in FIGS. 2A and 2B, the multilayer circuit board of the present invention includes a plurality of insulating bumps 102, a conductor layer 104, and a conductor layer 112. The conductive layer 104 and the conductive layer 112 use the top of the insulating bump 102 as a circuit connection point 120.

For example, a plurality of insulating bumps 102 are disposed between the substrate 100 and the substrate 106, and the tops of the plurality of insulating bumps 102 serve as circuit connection points 120. The conductive layer 104 is disposed on the substrate 100 and is connected to the circuit connection point 120. The conductive layer 112 is disposed on the substrate 106 and is connected to the circuit connection point 120.

A plurality of insulating bumps 102 are disposed on the substrate 100. The hardness of the insulating bump 102 is, for example, greater than the hardness of silver, that is, the hardness of the insulating bump 102 is, for example, greater than the Mohs hardness 2.7. The material of the insulating bump 102 includes ceramic materials, such as zirconia, alumina, and silicon dioxide , Titanium dioxide, silicon nitride, silicon carbide, or a combination thereof. Since the ceramic material is used to replace the conductive metal to make the bumps, the characteristics of the material can be used to avoid the skew of the bumps in the press-puncture process and ensure the yield and completion quality of the multilayer circuit board.

The conductive layer 104 is disposed on the substrate 100, and a part of the conductive layer 104 is located on top of the plurality of insulating bumps 102. The substrate 106 is disposed on the substrate 100 and has a plurality of openings 110 that respectively expose the conductive layers 104 on top of the plurality of insulating bumps 102.

The conductive layer 112 is disposed on the substrate 106, and the conductive layer 112 is electrically connected to the conductive layer 104 on top of the plurality of insulating bumps 102.

In one embodiment, a bonding adhesive layer 108 is further included between the substrate 100 and the substrate 106. The bonding adhesive layer 108 is, for example, a thermocompression bonding adhesive layer.

In one embodiment, a protective plate 114 is further disposed on the substrate 106. An adhesive layer 116 is further included between the protective plate 114 and the substrate 106. The bonding adhesive layer 116 is, for example, a thermocompression bonding adhesive layer.

In the multilayer circuit board and the manufacturing method thereof of the present invention, ceramic bumps are printed by 3D printing technology to produce insulating bumps, and 3D printing technology is used to print conductive lines (conductive layers) so that the insulating bumps are on the bumps. The lines form a conductive connection between circuit layers, replacing the commonly used via technology or the metal bumps in B2it technology.

Moreover, the use of 3D printing technology can complete the production of insulating bumps at one time, and the use of screen printing technology requires multiple re-copying processes to complete the production of insulating bumps. Using ceramic materials instead of conductive metals to make bumps, the characteristics of the material itself can be used to avoid the skew of the bumps during the press-puncture process and ensure the yield and completion quality of the multilayer circuit board.

Using 3D printing technology to replace the traditional etching process to complete the circuit board production, in addition to effectively reducing the complexity of multi-layer substrate production and the required consumables, and can effectively reduce the substrate manufacturing time and cost.

The multi-layer circuit board and the manufacturing method thereof of the present invention print conductive lines on an insulating substrate. Therefore, the circuit layout can be easily changed according to use requirements, and the use is extremely flexible.

In addition, in the multilayer circuit board and the manufacturing method thereof of the present invention, since an etching and electroplating process is not required, a green manufacturing method can be provided to reduce the disposal and discharge costs of sewage and waste.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

100, 106‧‧‧ substrate

102‧‧‧Insulated bump

104, 112‧‧‧ Conductor layer

104a, 112a‧‧‧ extension

104b, 112b‧‧‧ Connection

108, 116‧‧‧ Adhesive layer

110‧‧‧ opening

114‧‧‧protection plate

118‧‧‧ contact opening

120‧‧‧Circuit connection point

1A to 1G are schematic diagrams of a method for manufacturing a multilayer circuit board according to an embodiment of the present invention. 2A and 2B are a schematic cross-sectional view and a three-dimensional structure view of a multilayer circuit board according to an embodiment of the present invention.

Claims (4)

A method for manufacturing a multi-layer circuit board includes: forming a plurality of protruding bumps on a first substrate, wherein the plurality of bumps include a 3D printing method, and a material of the bumps is Ceramic material; forming a first conductor layer on the first substrate, and a part of the first conductor layer is located on top of the plurality of insulating bumps; forming a bonding adhesive layer on the second substrate; The first substrate and the second substrate, the insulating bump passes through the bonding adhesive layer and the second substrate and exposes the top; and a second conductor layer is formed on the second substrate, In addition, the second conductor layer is electrically connected to the first conductor layer on the top of the plurality of insulating bumps; wherein the first conductor layer and the second conductor layer are formed by using a 3D printing method. . The method for manufacturing a multilayer circuit board according to item 1 of the scope of patent application, wherein after forming the plurality of insulating bumps by a 3D printing method, a sintering process is further included. The method for manufacturing a multilayer circuit board according to item 1 of the scope of patent application, wherein after forming the bonding adhesive layer on the second substrate and before laminating the first substrate and the second substrate, the method further includes: A plurality of openings are formed in the adhesive layer. The method for manufacturing a multilayer circuit board according to item 1 of the scope of patent application, wherein laminating the first substrate and the second substrate includes performing a hot-pressing process.