TWI691245B - Manufacturing method of circuit board - Google Patents

Abstract

A manufacturing method of a circuit board includes forming a through hole on a resin layer that is perforated on a substrate and an impeded layer by a laser drill and/or a mechanical drill, until a portion of the impeded layer exposed and the other portion of the impeded layer covered by the resin layer; sputtering a first conductive layer on a surface of the resin layer and a surface of the exposed impeded layer; electroless plating a second conductive layer on the first conductive layer; plating a third conductive layer with a pattern on the second conductive layer; filling the through hole for electrically connecting the first conductive layer, the second conductive layer and the third conductive layer; and etching the third conductive layer to the first conductive layer sequentially until the etched first conductive layer exposed the resin layer underneath to form an opening corresponding to the pattern.

Description

Circuit board manufacturing method

The present invention relates to a method for manufacturing a circuit board, in particular, a first metal layer, a second metal layer and a circuit pattern having a circuit pattern are formed on a substrate by sequentially using a sputtering process, a chemical plating process, and an electroplating process The three metal layers are then etched to etch part of the first and second metal layers to form a thin line width/line spacing line.

In recent years, with the rapid development of large-scale integrated circuits (VLSI), connection lines have become thinner and thinner. For example, in the semiconductor 22nm technology, the wafer density and signal processing capability per unit area have been continuously improved, which has forced the connection lines to be further miniaturized. As a result, the existing production, manufacturing equipment and processes are facing unprecedented challenges. Furthermore, in order to further increase the packaging density, the chips are stacked to form a three-dimensional package. At this time, the line width/line spacing of the circuit substrate needs to be reduced from 100um to 30-50um. For the industry's requirements to continuously reduce the line width/line spacing, the copper surface structure requirements of the circuit are also constantly strict. Generally, the roughness Rz of copper in a printed circuit board (Printed Circuit Board, PCB) is 5-7um, where the roughness of the carrier board must be less than 5um, but for line width/line spacing 10-20um, the copper of the line The surface roughness Rz of the wire is generally 2um, otherwise it is easy to deform the wire and cause the overall electrical function to fail, or the wire will cause a short circuit due to the residual copper, which cannot achieve high-precision and high-reliability interconnect .

In the conventional technology, the semi-additive process (Semi Additive Process, SAP) is generally used to make a line with a thin line width/line spacing below 50um, and the line width is less than 25um Semi-additive SAP technology is to use plain ABF resin as the insulating layer material, or to use Primer Coated Copper Foil (PCF) and prepreg (or film, Prepreg) produced by Mitsubishi Gas. Be achieved in a combined manner. For resin-coated copper foil (PCF), a layer of resin with a thickness of 2-3 microns is mainly coated on the surface of the copper foil roughened on one side, after curing, it is formed by pressing together with the prepreg, and after pressing , The copper foil can be removed to form a resin surface with a certain surface roughness, so the chemical copper plating layer (or chemical skin plating method) can be obtained on the resin surface to obtain a chemically copper plating layer with good binding force, so as to make the requirements more Fine lines.

Take the SAP method using a resin-coated copper foil (PCF) as an example. The specific method is to first press the PCF on the inner layer circuit, and then remove the copper foil on the PCF, leaving the resin with high surface characteristics for By means of chemical skin plating, a circuit pattern layer with fine line width/line spacing is formed on the surface of the resin.

However, the disadvantage of the above-mentioned conventional technology is that the resin left after removing the PCF copper foil is not stable enough, so that the circuit pattern layer formed by the chemical skin plating method is easily broken, peeled, and peeled off due to insufficient adhesion. It is difficult to keep the line pattern layer filled with blind holes as the upright shape of the connecting post without deviation, which affects the electrical quality of the line and the reliability of operation.

Therefore, there is a great need for a method of manufacturing a circuit board, in which a first metal layer, a second metal layer and a circuit pattern with a stack are formed on the substrate by sequentially using sputtering, chemical plating, electroless plating, or electroplating The third metal layer is then etched to etch part of the first and second metal layers to form a thin line width/line spacing circuit, thus solving all the problems of the above-mentioned conventional techniques.

The main object of the present invention is to provide a method for manufacturing a circuit board, which is used to manufacture a circuit board that is easy to form a thin line width/line distance circuit, and to improve the accuracy of the circuit.

First, the manufacturing method of the circuit board of the present invention includes preparing a substrate, and the substrate has a blocking layer and a resin layer, wherein the resin layer is on the blocking layer, and the surface has a roughness of Ra=0~1um and Rz=0~10um , And is located on the surface of the substrate, and the blocking layer has a pattern, and can be composed of metal or alloy.

Next, laser drilling and/or mechanical drilling are used to penetrate the resin layer to form at least one via hole, wherein the via hole is a blind hole penetrating the bottom of the substrate and stops at the blocking layer without entering the blocking layer, that is, The blocking layer prevents the via hole from entering. In addition, the via hole can also be directly formed by laser drilling of the laser beam. For example, a photoresist layer with a specific pattern can be formed on the resin layer first, and then the photoresist layer can be used as a photomask for laser Etching laser drilling to form via holes.

Then, a sputtering process is performed to form a first metal layer on the resin layer and cover the surface of the via hole. After that, chemical plating or electroless plating is performed to form a second metal layer to cover the surface of the first metal layer. Next, a third metal layer is formed on the second metal layer by electroplating, wherein the third metal layer has a circuit pattern to expose a portion of the second metal layer and fill the via holes, so that the first metal layer and the second metal The layer and the third metal layer can be electrically connected to each other.

Finally, the exposed second metal layer is subjected to circuit etching, and the first metal layer underneath is further etched to expose part of the resin underneath to complete the required circuit board fabrication.

In addition, the resin layer may further include a reinforcing material uniformly distributed in the resin substrate, and the reinforcing material may include a plurality of glass fibers or carbon fibers to increase the flexibility resistance and enhance the mechanical strength of the overall structure, which can be avoided Deflection and deformation occurred.

In addition, the upper surface of the resin layer may be covered with a copper foil layer, so when forming the via hole, the copper foil layer is pre-treated, such as blackening or browning the copper foil layer to oxidize the copper foil layer Then, laser etching treatment is performed to form via holes. The upper surface and /or the lower surface of the substrate may also have inner layer circuits, for example, made of a conductive metal material, and have electrical patterns.

More specifically, the first metal layer may include an upper metal layer and a lower metal layer, wherein the upper metal layer is stacked on the lower metal layer, and the lower metal layer is stacked on the exposed portion of the inner circuit layer of the substrate. In addition, the upper metal layer includes copper (Cu), and the lower metal layer includes titanium (Ti), chromium (Cr), or tantalum (Ta), and the second metal layer and the third metal layer may include copper. The first metal layer may further include a bottom metal layer located below the above-mentioned lower metal layer and contacting the exposed portion of the inner circuit layer, wherein the bottom metal layer may include titanium nitride (TiN).

Another object of the present invention is to provide a method for manufacturing a circuit board, which includes preparing a substrate, forming a via hole, forming a first metal layer, forming a second metal layer, forming a third metal layer, and etching a circuit, wherein the via hole is through The through hole of the substrate, and the first, second, and third metal layers sequentially cover the upper surface, the lower surface, and the surface of the through hole of the substrate, and the third metal layer has a circuit pattern, which can expose part of the second metal layer And fill the entire through hole. In particular, the first and second metal layers are etched and removed during circuit etching by the circuit pattern of the third metal layer, thereby exposing part of the resin layer under the first metal layer.

Specifically, the circuit board manufactured by the present invention can have a line width/pitch less than 10um, which greatly improves the quality of the circuit board, especially the process steps are simple, easy to implement, and at the same time can reduce the manufacturing cost, has a price advantage, can It really meets the requirements of electronic components packaging and electronic application products for fine line width/line spacing of circuit boards, which is conducive to market competition.

10: substrate

12: Block layer

20: resin layer

30: Via

40: First metal layer

50: second metal layer

60: third metal layer

62: opening

S10~S60: Step

The first figure shows the operation flow chart of the manufacturing method of the circuit board according to the first embodiment of the present invention.

FIGS. 2A to 2F sequentially show the processing steps of the manufacturing method of the first embodiment of the present invention.

FIGS. 3A to 3F sequentially show the processing steps of the manufacturing method of the second embodiment of the present invention.

The embodiments of the present invention will be described in more detail below with reference to icons and component symbols, so that those skilled in the art can implement them after studying this specification.

Referring to the first figure, an operation flowchart of the method for manufacturing a circuit board according to the first embodiment of the present invention. As shown in the first figure, the manufacturing method of the circuit board according to the first embodiment of the present invention mainly includes the steps S10, S20, S24, S30, S40, S50, and S60 performed in order to make a line with a fine line width/pitch Circuit board. In addition, in order to further facilitate the understanding of the technical features of the manufacturing method of the present invention, reference may be made to the schematic diagrams of the second drawings A to F at the same time.

First, the manufacturing method of the present invention starts from step S10 to prepare a substrate 10, as shown in FIG. 2A, in which the substrate 10 is provided with a blocking layer 12 and a resin layer 20. The resin layer 20 is on the blocking layer 12 and located on the surface of the substrate 10, and the blocking layer 12 has a pattern and is made of metal or alloy. The resin layer 20 can be formed by a pressing method. However, the present invention is not limited to this, and other methods such as coating and spraying can also be used. In particular, the resin layer 20 includes a resin base material, wherein the resin base material includes epoxy resin, FR4, FR5, Modified FR4) Silicone (Silicon), BT resin, polyphenylene oxide resin (PPO), polyimide (PI ), ABF (Ajinomoto build-up film), polypropylene or Photo Imageable Dielectric Material (PIDM), and the surface of the resin layer 20 has roughness of Ra=0~1um and Rz=0~10um.

Next, proceed to step S20, as shown in FIG. 2B, use laser drilling and/or mechanical drilling to penetrate the resin layer 20 to form at least one via hole 30, wherein the via hole 30 is a blind hole penetrating the bottom of the substrate 10 Hole, and stop at the blocking layer 12 without entering the blocking layer 12. That is, the blocking layer 12 is used to block the via 30 from entering. The via hole 30 can be directly formed by laser drilling of the laser beam, but the present invention is not limited to this. For example, a photoresist layer with a specific pattern can also be formed on the resin layer 20 (not shown in the figure). (Display), and then use the photoresist layer as a photomask for laser drilling to perform laser etching to form at least one via 30 as needed.

Then in step S30, as shown in FIG. 2C, a sputtering process is performed to form a first metal layer 40 on the resin layer 20, and the first metal layer 40 covers the surface of the via hole 30.

Step S40 is performed, as shown in the second D figure, a chemical plating process or an electroless plating process is performed to form a second metal layer 50, wherein the second metal layer 50 covers the surface of the first metal layer 40.

In step S50, as shown in the second E diagram, a third metal layer 60 is formed on the second metal layer 50 by electroplating, wherein the third metal layer 60 has a circuit pattern to expose a portion of the second metal layer 50, and fill the via 30 so that the first metal layer 40, the second metal layer 50, and the third metal layer 60 can be electrically connected to each other.

Finally, in step S60, as shown in the second F diagram, the exposed second metal layer 50. Etching the circuit, and further etching the underlying first metal layer 40, thereby exposing a part of the resin layer 20 underneath, thereby completing the required circuit board fabrication.

The above-mentioned resin layer 20 may further include a reinforcing material (not shown) uniformly distributed in the resin substrate, and the reinforcing material may include a plurality of glass fibers or carbon fibers to increase the flexibility resistance and strengthen the overall structure Mechanical strength to avoid deflection and deformation.

In addition, in the step S10 of preparing the substrate 10, the upper surface of the resin layer 20 of the substrate 10 may be covered with a copper foil layer (not shown in the figure). Therefore, in the step S20 of forming the via hole 30, it is first Pre-treating the copper foil layer, such as blackening or browning the copper foil layer to oxidize the surface of the copper foil layer, followed by laser etching to form at least one via 30 .

Furthermore, the upper and lower surfaces of the substrate 10 may have inner layer circuits (not shown in the figure), or the upper or lower surface of the substrate 10 may have inner layer circuits (not shown in the figure), The inner layer circuit is composed of a metal conductive material, and may further have an electrical pattern.

More specifically, the first metal layer 40 may further include an upper metal layer and a lower metal layer (not shown), wherein the upper metal layer is stacked on the lower metal layer, and the lower metal layer is stacked on the substrate 10 On the exposed portion of the inner circuit layer, because the via hole 30 formed in step S20 exposes part of the inner circuit layer. In addition, the upper metal layer includes copper (Cu), and the lower metal layer includes titanium (Ti), chromium (Cr), or tantalum (Ta), and the second metal layer 50 and the third metal layer 60 may include copper.

Furthermore, the first metal layer 40 may further include a bottom metal layer (not shown in the figure), which is located below the lower metal layer and contacts the exposed portion of the inner circuit layer, wherein the bottom metal layer may include titanium nitride (TiN).

In addition, the second embodiment of the present invention is another method of manufacturing a circuit board, wherein the operation flowchart of the manufacturing method of the second embodiment is still as shown in the first figure, including steps S10, S20, S24, S30, S40, S50 And S60, used to make a circuit board that is easy to form thin line width/line spacing, and the second embodiment is similar to the first embodiment, but to further facilitate the understanding of the characteristics of this embodiment, please cooperate with the third A to the third Schematic diagram of three F diagrams.

First, the operation of step S10 is performed to prepare the substrate 10, wherein the substrate 10 has resin layers 20 on the upper and lower surfaces, as shown in FIG. 3A. Next, proceed to step S20, use laser drilling and/or mechanical drilling to penetrate the substrate 10 and the resin layer 20 on the upper and lower surfaces of the substrate 10, thereby forming at least one via 30, and the at least one via 30 It is essentially a through hole, as shown in Figure 3B.

In step S30, as shown in FIG. 3C, a sputtering process is performed, and a first metal layer 40 is mainly formed on the resin layer 20, and the first metal layer 40 covers the surface of the via hole 30. Step S40 is executed, as shown in the third D figure, a chemical plating process or an electroless plating process is performed to form a second metal layer 50, wherein the second metal layer 50 covers the surface of the first metal layer 40. Then, proceed to step S50. As shown in the third diagram E, on the second metal layer 50, a third metal layer 60 is formed by electroplating, wherein the third metal layer 60 has a circuit pattern, and has a An opening 62 corresponding to the exposed portion of the second metal layer 50 and filling the via 30 so that the first metal layer 40, the second metal layer 50 and the third metal layer 60 can be electrically connected to each other to complete the process The production of the required circuit board.

Finally, in step S60, as shown in FIG. 3F, the exposed second metal layer 50 is etched, and the underlying first metal layer 40 is further etched to expose part of the resin layer 20 underneath to complete the required Circuit board production.

The remaining elements of the second embodiment are the same as those of the first embodiment, and are not repeated here.

In summary, the main feature of the manufacturing method of this embodiment is that a first metal layer with high adhesion is formed on the resin layer by sputtering, and a second metal is formed on the first metal layer by chemical skin plating Layer, and then use electroplating to form a third metal layer to cover the second metal layer and fill the blind holes, and because the first metal layer provides better surface characteristics, the second metal layer and the third metal layer are more stable, and After the circuit is etched, a circuit with a line width/line distance of less than 10um can be formed, so that it can truly meet the requirements of electronic device packaging and electronic application products for the fine line width/line distance of the circuit board.

In particular, the first metal layer includes an upper metal layer composed of easily oxidized copper or aluminum, and a lower metal layer composed of titanium, chromium, or tantalum for improving activity, which can improve the workability and subsequent processing quality. In addition, the first metal layer may further include a bottom metal layer made of titanium nitride, located under the lower metal layer, for contacting the inner circuit layer, so that the overall material strength of the first metal layer and the inner circuit layer The cohesion between them has been greatly improved. Furthermore, the second metal layer can be used as an interlayer conduction layer, and the third metal layer can be used to increase the overall thickness of the metal layer, and at the same time, the metal fills the via hole.

Therefore, the circuit board manufactured by the method of the present invention does have higher operating stability and reliability, and effectively solves the shortcomings of the conventional technology.

Since the technology of the present invention is not found in published journals, periodicals, magazines, media, and exhibition venues, it is novel and can be broken through the current technical bottlenecks for specific implementation, which is indeed progressive. In addition, the present invention can solve the problems of conventional technology, improve the overall use efficiency, and can achieve industrially useful value.

The above is only for explaining the preferred embodiments of the present invention and is not intended to be In order to limit the present invention in any form, any modifications or changes made to the present invention under the same spirit of the invention should still be included in the scope of protection of the present invention.

S10~S60‧‧‧Step

Claims (19)

A method for manufacturing a circuit board, comprising: laser drilling and/or mechanical drilling through a resin layer on a substrate and a blocking layer until a part of the blocking layer is exposed and another of the blocking layer Partly covered by the resin layer to form at least one via hole; sputtered on the surface of the resin layer and the surface of the exposed blocking layer, on the surface of the resin layer and the exposed layer of the blocking A first metal layer is formed on the surface; the first metal layer is chemically plated or electrolessly plated to form a second metal layer on the first metal layer; the second metal layer is electroplated and formed on the second A third metal layer is formed on the metal layer, the third metal layer is configured with a circuit pattern, and fills the at least one via hole, thereby electrically connecting the first metal layer, the second metal layer, and the third metal layer; And sequentially etching the third metal layer, the second metal layer, and the first metal layer with the circuit pattern until the etched first metal layer is exposed to the resin layer below to form a circuit corresponding to the circuit An opening in the pattern. The method for manufacturing a circuit board according to claim 1, wherein a part of the third metal layer corresponds to the via hole located below and the other part of the third metal layer is configured with the circuit pattern. The method for manufacturing a circuit board according to claim 1, wherein the at least one via hole is formed by a laser drilling. The method for manufacturing a circuit board according to claim 1, wherein the formation of the at least one via hole is to first form a photoresist layer with a specific pattern on the resin layer, and then use the photoresist The layer is used as a mask to perform a laser drilling process of laser etching to form the at least one via hole. The method for manufacturing a circuit board according to claim 1, wherein an upper surface of the resin layer is covered with a copper foil layer, and the formation of the at least one via is to perform a pre-treatment on the copper foil layer first, including The copper foil layer is subjected to a blackening treatment or a browning treatment, and the blackening treatment or the browning treatment is used to oxidize the surface of the copper foil layer, followed by a laser etching treatment to form the at least one Vias. The method for manufacturing a circuit board according to claim 1, wherein the resin layer comprises a resin base material, and the resin base material comprises epoxy resin, FR4, FR5, Modified FR4) Silicone, BT resin, polymer Phenyl ether resin (PPO), polyimide (PI), Ajinomoto build-up film (ABF), polypropylene or photo imageable dielectric material (PIDM), and the resin The surface of the layer has a roughness of Ra=0~1um and Rz=0~10um. The method for manufacturing a circuit board according to claim 1, wherein the substrate has an inner circuit layer on an upper surface and/or a lower surface, respectively. The method for manufacturing a circuit board according to claim 1, wherein the first metal layer includes an upper metal layer and a lower metal layer, and the upper metal layer is stacked on the lower metal layer, and the lower metal layer is Stacked on the exposed portion of the inner circuit layer, the upper metal layer includes copper (Cu), and the lower metal layer includes titanium (Ti), chromium (Cr) or tantalum (Ta), the second metal layer and the The third metal layer contains copper. The method for manufacturing a circuit board according to claim 1, wherein the first metal layer further includes a bottom metal layer under the lower metal layer and in contact with the exposed portion of the inner circuit layer, and the bottom metal The layer contains titanium nitride (TiN). The method for manufacturing a circuit board according to claim 1, wherein the resin layer further includes a reinforcing material uniformly distributed in the resin substrate, and the reinforcing material includes a plurality of glass fibers or carbon fibers. A method for manufacturing a circuit board, comprising: penetrating a substrate and a resin layer with a laser drilling and/or a mechanical drilling, and forming a through hole in the substrate and the resin layer, wherein an upper surface of the substrate And the lower surface are respectively provided with the resin layer; the surface of the resin layer is sputtered, and a first metal layer is formed on the surface of the resin layer; the first metal layer is chemically plated or electrolessly plated, and the A second metal layer is formed on the surface of the first metal layer; the second metal layer is electroplated and a third metal layer is formed on the surface of the second metal layer, a portion of the third metal layer corresponding to the bit A circuit pattern is disposed on the via hole below and the other part of the third metal layer; the third metal layer also fills the via hole to electrically connect the first metal layer and the second metal layer; and The circuit pattern sequentially etches the third metal layer, the second metal layer, and the first metal layer until the etched first metal layer is exposed to the resin layer underneath to form a pattern corresponding to the circuit pattern An opening. The method for manufacturing a circuit board according to claim 11, wherein the at least one via hole is formed by a laser drilling. The method for manufacturing a circuit board according to claim 11, wherein the formation of the at least one via hole is to first form a photoresist layer with a specific pattern on the resin layer, and then use the photoresist layer as a photomask A laser drilled by a laser etching process is used to form the at least one via hole. The method for manufacturing a circuit board according to claim 11, wherein an upper surface of the resin layer is covered with a copper foil layer, and the formation of the at least one via hole is to perform a pretreatment on the copper foil layer first, including The copper foil layer is subjected to a blackening treatment or a browning treatment, and the blackening treatment or the browning treatment is used to oxidize the surface of the copper foil layer, followed by a laser etching treatment to form the at least one Vias. The method for manufacturing a circuit board according to claim 11, wherein the resin layer comprises a resin base material, and the resin base material comprises epoxy resin, FR4, FR5, Modified FR4) silicone, BT resin, polymer Phenyl ether resin (PPO), polyimide (PI), ABF, polypropylene or photo-imageable dielectric material (PIDM), and the surface of the resin layer has one of Ra=0~1um and Rz=0~10um Roughness. The method for manufacturing a circuit board according to claim 11, wherein the substrate has an inner circuit layer on an upper surface and/or a lower surface, respectively. The method for manufacturing a circuit board according to claim 16, wherein the first metal layer includes an upper metal layer and a lower metal layer, and the upper metal layer is stacked on the lower metal layer, and the lower metal layer is Stacked on the exposed part of the inner circuit layer, the upper metal The layer includes copper (Cu), and the lower metal layer includes titanium (Ti), chromium (Cr), or tantalum (Ta), and the second metal layer and the third metal layer include copper. The method for manufacturing a circuit board according to claim 17, wherein the first metal layer further includes a bottom metal layer under the lower metal layer and in contact with the exposed portion of the inner circuit layer, and the bottom metal The layer contains titanium nitride (TiN). The method of manufacturing a circuit board according to claim 11, wherein the resin layer further includes a reinforcing material uniformly distributed in the resin substrate, and the reinforcing material includes a plurality of glass fibers or carbon fibers.

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