CN116939984A

CN116939984A - Manufacturing method of circuit board structure and manufactured circuit board structure

Info

Publication number: CN116939984A
Application number: CN202210344604.2A
Authority: CN
Inventors: 许议文; 许日能
Original assignee: Jialianyi Tech Suzhou Co ltd; Career Electronic Kunshan Co ltd
Current assignee: Jialianyi Tech Suzhou Co ltd; Career Electronic Kunshan Co ltd
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2023-10-24

Abstract

The manufacturing method of the circuit board structure comprises the steps of providing a substrate, wherein the substrate comprises a base material layer and two copper layers, and each copper layer is formed on a first surface and a second surface which are opposite to each other; forming two metal-clad conductor layers through chemical plating, sputtering or electroplating, wherein the two metal-clad conductor layers respectively cover the surfaces of the two copper layers; drilling holes from the surface of the metal-coated conductor layer on the first surface side, and conducting the holes to the copper layer exposed on the second surface of the substrate layer; forming a metallization layer in a chemical mode, wherein the metallization layer covers the surfaces of the holes and the surfaces of the two metal-coated conductor layers; forming a copper-clad layer by electroplating, wherein the copper-clad layer covers the holes, the metal-clad conductor layers on the first surface side and the second surface side; the chemical etch removes portions of the copper-clad layer that exceed the height of the copper layer. The two metal-clad conductor layers are removed by chemical etching.

Description

Manufacturing method of circuit board structure and manufactured circuit board structure

Technical Field

The invention relates to a manufacturing method of a circuit board structure and the manufactured circuit board structure.

Background

The common selective electroplating method of the circuit board is mainly to select a photoresist material as a material of the shielding layer, and because the shielding layer adopts the photoresist material, the photoresist characteristics are usually acid-resistant or alkali-resistant, and can not resist acid or alkali simultaneously, and acidic and alkaline medicinal liquid exists in a main flow metallization system at the same time, the process must be completed by metallization before the photoresist material is covered. The process is to carry out metallization after drilling and hole cleaning, then to match with photoresist shielding, exposing and developing to expose the metallized holes, and then to carry out electroplating, wherein the drilling process and the exposure process have the technical tolerance problem, so that the photoresist hole opening process is to carry out hole opening according to the drilling position, equipment with automatic alignment (a CCD exposure machine or a digital direct drawing exposure machine) is to be adopted, the hole opening size is to be enlarged due to the progressive problem of tolerance, and a convex part is to be formed around the hole opening after electroplating. In the circuit fabrication, in order to effectively cover the protruding portion, the photoresist selection thickness cannot be thinned, which results in limitation of resolution and etching molding, and influences the fabrication of fine circuit of the circuit board circuit structure.

In the prior art, although a new metallization system exists, the whole metallization process is neutral or slightly acidic, the operation condition of the photoresist can be compatible relatively, the metallization process is carried out with the photoresist, the photoresist surface has conductivity, the photoresist is plated on the hole of the circuit board in the electroplating process, so that the plating material on the photoresist is removed for smoothly removing the photoresist, the photoresist has the conductive property after metallization because of the non-conductive material of the photoresist, but after all, the non-metal material is not uniform as metal conductivity, the problem of uneven plating copper coverage on the photoresist is easily formed, the difficulty of removing the plating on the photoresist later is influenced, moreover, the bump added on the copper substrate can be formed on the difficulty of removing because of the thickness of the photoresist, and the use of the neutral or slightly acidic metallization system is limited because the photoresist material can be used only.

Disclosure of Invention

In view of the above, an embodiment of the present disclosure provides a method for manufacturing a circuit board structure, including providing a substrate, wherein the substrate includes a base layer and two copper layers, and each copper layer is formed on a first surface and a second surface opposite to the base layer; and forming two metal-clad conductor layers by electroplating, wherein the two metal-clad conductor layers are respectively covered on the surfaces of the two copper layers. Drilling holes from the surface of the metal-coated conductor layer on the first surface side, and conducting the holes to the copper layer exposed on the second surface of the substrate layer; forming a metallization layer in a chemical mode, wherein the metallization layer covers the surfaces of the holes and the surfaces of the two metal-clad conductor layers; and forming a copper-clad layer by electroplating, wherein the copper-clad layer covers the surface of the hole and extends to the surface of the metal-clad conductor layer positioned on the first surface side, and covers the surface of the metal-clad conductor layer on one side of the second surface. The copper-clad layer is removed by chemical etching partially over the height of the copper layer. The two metal-clad conductor layers are removed by chemical etching.

In some embodiments, the metal-clad conductor layer is chromium, nickel, aluminum, titanium, tin, platinum, gold, or silver.

In some embodiments, the two copper layers are connected by a copper-clad layer of at least one hole.

In some embodiments, during the drilling process, at least one hole is conducted to the metal-clad conductor layer on one side of the second surface.

In some embodiments, the copper-clad layer is substantially aligned with the height of the copper layer by chemical etching during removal of the copper-clad layer partially beyond the height of the copper layer by chemical etching.

In some embodiments, the at least one hole is formed by laser drilling, mechanical drilling, or punching.

In some embodiments, the material of the two metal-clad conductor layers is an acid-alkali-resistant metal material, and the thickness of the metal-clad conductor layers is 0.1 to 20 μm.

In some embodiments, after removal of the two metal-clad conductor layer by chemical etching is completed; covering the two photoresist layers on the surfaces of the two copper layers, and exposing and developing the two photoresist layers to form a circuit pattern structure; etching to remove the surface of each copper layer uncovered by each photoresist layer; and removing the two photoresist layers.

In addition, according to one embodiment, a circuit board structure is provided, which is manufactured by the manufacturing method of the above embodiments.

In summary, by plating the metal conductor layer on the substrate, the metal conductor layer is not limited by neutral or weak acid metallization system, the current mainstream metallization system can be selected, the efficiency of manufacturing the circuit board structure is improved, the multiple elements of the manufacturing method are increased, the metal conductor layer is covered on the two copper layers by adopting chemical deposition or electroplating, the thickness is not limited by the manufacturing thickness of the photoresist, and the material conductivity of the metal conductor layer changes the conventional pattern electroplating into the whole plate electroplating characteristic, so that the overall electroplating uniformity is easier to control than the pattern electroplating, and the phenomenon that the removal is not easy due to the overlarge thickness difference when the electroplated layer on the metal conductor layer is removed later.

The invention will now be described in more detail with reference to the drawings and specific examples, which are not intended to limit the invention thereto.

Drawings

FIG. 1 is a schematic diagram (one) of a circuit board structure manufacturing method according to a first embodiment;

FIG. 2 is a schematic diagram of a circuit board structure manufacturing method according to a first embodiment (II);

FIG. 3 is a schematic diagram of a circuit board structure manufacturing method according to a first embodiment;

FIG. 4 is a schematic diagram of a circuit board structure manufacturing method according to a first embodiment;

FIG. 5 is a schematic diagram (fifth) of a circuit board structure manufacturing method according to a first embodiment;

FIG. 6a is a schematic diagram of a circuit board structure manufacturing method according to a first embodiment;

FIG. 6b is a schematic diagram of a copper-clad structure of a circuit board structure according to another aspect of the first embodiment;

fig. 7 is a schematic diagram (seventh) of a circuit board structure manufacturing method according to a first embodiment;

FIG. 7a is a schematic diagram (eighth) of a circuit board structure manufacturing method according to a first embodiment;

fig. 7b is a schematic diagram (nine) of a circuit board structure manufacturing method according to a first embodiment;

FIG. 7c is a schematic diagram of a copper-clad structure of a circuit board structure according to another aspect of the first embodiment;

FIG. 8 is a schematic diagram (one) of a circuit board structure manufacturing method according to a second embodiment;

FIG. 9 is a schematic diagram (II) of a circuit board structure manufacturing method according to a second embodiment;

FIG. 10 is a schematic diagram (III) of a circuit board structure manufacturing method according to a second embodiment;

FIG. 11 is a flowchart (one) of a method for fabricating a circuit board structure according to a first embodiment;

fig. 12 is a flowchart (ii) of a method for manufacturing a circuit board structure according to a first embodiment.

Wherein reference numerals are used to refer to

100 circuit board structure

10 substrate

11 substrate layer

111 first surface

112 second surface

12a, 12b copper layer

13a, 13b metal-clad conductor layer

14 metallization layer

15 copper-clad layer

16 photoresist layer

161 line pattern structure

20 holes

21 pore wall

22 bottom of hole

30 holes

31 pore wall

S10-S19 step

Detailed Description

The structural and operational principles of the present invention are described in detail below with reference to the accompanying drawings:

referring to fig. 1 to 6a, fig. 7 and fig. 11, fig. 1 to 6a are schematic structural diagrams (one) to (six) of a circuit board structure manufacturing method according to a first embodiment, fig. 7 is a schematic structural diagram (seven) of a circuit board structure manufacturing method according to a first embodiment, and fig. 11 is a flowchart (one) of a circuit board structure manufacturing method according to a first embodiment. As shown in fig. 1 and 11, the manufacturing method of the circuit board structure 100 of the present embodiment includes providing a substrate 10 (step S10), wherein the substrate 10 includes a base material layer 11 and two copper layers 12a and 12b. The substrate layer 11 has a first surface 111 and a second surface 112 opposite to each other, and the two copper layers 12a, 12b are formed on the first surface 111 and the second surface 112 of the substrate layer 11, respectively. For convenience of the following description, the copper layer on the first surface 111 side is illustrated as copper layer 12a, and the copper layer on the second surface 112 side is illustrated as copper layer 12b. That is, the first surface 111 and the second surface 112 of the substrate layer 11 can be used to manufacture the circuit board structure 100 with the same or different specifications, or only a single side surface can be used to manufacture the circuit board structure 100. In the first embodiment, the circuit board structure 100 is manufactured by using a single side surface as an example, but not limited thereto.

As shown in fig. 2 and 11, the two metal-clad conductor layers 13a and 13b are formed by electroless plating, sputtering, or electroplating, and the two metal-clad conductor layers 13a and 13b are respectively covered on the surfaces of the two copper layers 12a and 12b (step S11). For convenience of the following explanation, the metal-clad conductor layer on the first surface 111 side is illustrated as a metal-clad conductor layer 13a, and the metal-clad conductor layer on the second surface 112 side is illustrated as a metal-clad conductor layer 13b. In the first embodiment, the metal conductor layers 13a and 13b are made of metal materials capable of resisting acid and alkali, and the thickness is 0.1 to 20 μm, and the metal conductor layers 13a and 13b can be stripped more efficiently and conveniently in the stripping operation. In the first embodiment, the acid-and alkali-resistant metal material is, for example, nickel, but not limited thereto, and may be chromium, aluminum, titanium, tin, platinum, gold or silver.

As shown in fig. 3 and 11, holes 20 are formed by drilling holes 20 from the surface of the metal-clad conductor layer 13a located on one side of the first surface 111 (step S12), and the holes 20 are conducted to the copper layer 12b exposed on the second surface 112 of the substrate layer 11. In the first embodiment, the holes 20 are formed by laser drilling, but the holes 20 may be formed by mechanical drilling or punching. Here, two holes 20 are taken as an example, but not limited thereto. The hole 20 sequentially passes through the metal-clad conductor layer 13a, the copper layer 12a and the substrate layer 11 from the metal-clad conductor layer 13a on the side of the first surface 111 to the copper layer 12b on the side of the second surface 112, and forms the hole 20. The hole 20 includes a hole wall 21 and a hole bottom 22, and the hole wall 21 includes a metal-clad conductor layer 13a, a copper layer 12a and a side surface of the base material layer 11 exposed by drilling. The hole bottom 22 includes a surface of the copper layer 12b bonded to the second surface 112.

As shown in fig. 4 and 11, the metallization layer 14 is formed chemically (step S13), and the metallization layer 14 covers the surface of the hole 20 and the surfaces of the two metal-clad conductor layers 13a and 13b. In the first embodiment, the metal-clad conductor layers 13a, 13b are not limited to neutral or weak acidic metallization systems, and alkaline metallization systems may be used. In addition, the metal-clad conductors are able to adsorb the metallization layer 14 on average during the metallization process. In the first embodiment, the surface of the hole 20 and the surfaces of the two metal-clad conductor layers 13a, 13b are formed and covered by a weakly alkaline, neutral or weakly acidic metallization system. That is, the metallization layer 14 covers the surface of the metal-clad conductor layer 13a on the side of the first surface 111 and the surface of the metal-clad conductor layer 13b on the side of the second surface 112. In addition, the coverage of the metallization layer 14 does not include portions of copper material, such as the side surfaces of the copper layer 12a exposed by the drill holes and the surfaces of the copper layer 12b exposed by the drill holes.

As shown in fig. 5 and 11, after the metallization layer 14 is formed, a copper-clad layer 15 is formed by electroplating (step S14), the copper-clad layer 15 covering the surface of the hole 20 and extending to the surface of the metal-clad conductor layer 13a located on the side of the first surface 111, and covering the surface of the metal-clad conductor layer 13b on the side of the second surface 112. In the first embodiment, the surfaces of the hole 20, i.e., the metal-clad conductor layer 13a, the copper layer 12a and the side surfaces of the base material layer 11 exposed by drilling are formed and covered by electroplating. In the first embodiment, the copper layer 12a on the first surface 111 side and the copper layer 12b on the second surface 112 side are connected by the copper-clad layer 15 formed in the hole 20.

As shown in fig. 6a, 6b and 11, after the plating is completed, the copper-clad layer 15 partially exceeding the height of the copper layer 12a on the side of the first surface 111 and the copper-clad layer 15 on the side of the second surface 112 are removed by chemical etching (step S15). In the first embodiment, the copper-clad layer 15 removed by the etching may be removed by removing the copper-clad layer 15 exceeding the height of the copper layer 12a located on the side of the first surface 111 and the copper-clad layer 15 located on the side of the second surface 112, and making the copper-clad layer 15 located on the side of the first surface 112 substantially aligned with the height of the copper layer 12a, as shown in fig. 6a, for the convenience of subsequent wiring. In addition, the heights of the copper clad layer 15 and the copper layer 12a may have slight tolerances, for example, the height of the copper clad layer 15 is slightly higher than the copper layer 12a or slightly lower than the copper layer 12a. Alternatively, the copper-clad layer 15 removed by etching may be a copper-clad layer structure of another aspect of the first embodiment shown in fig. 6b, where fig. 6b is a schematic view (a) of a circuit board structure manufacturing method according to another aspect of the first embodiment. In another embodiment, as shown in fig. 6b, the copper-clad layer 15 is removed by chemical etching to be aligned with the metal-clad conductor layer 13a by a portion exceeding the height of the copper layer 12a on one side of the first surface 111 for the subsequent line fabrication. This is suitable for the case where the thickness of the metal-clad conductor layer 13a is thin (e.g., 5 μm or less), at this time, the copper-clad layer 15 extending to only the surface of the metal-clad conductor layer 13a located on the side of the first surface 111 may be removed, and the height of the copper-clad layer 15 may be slightly higher than that of the copper layer 12a as shown in fig. 6 b. However, when the metal-clad conductor layer 13a is removed, the copper-clad layer 15 slightly protrudes from the copper layer 12a, but the thickness is very thin, so that the subsequent circuit process is not affected.

Continuing with the description of the steps of fig. 6a, as shown in fig. 7 and 12, after the chemical etching is completed, the metal-clad conductor layers 13a and 13b are removed (step S16), so as to complete the circuit board structure 100.

Specifically, the metallization and plating range is increased by the two metal-clad conductor layers 13a and 13b, and when the plating process is performed, the copper-clad layer 15 extends to the surface of the metal-clad conductor layer 13a, then the copper-clad layer 15 exceeding the height range of the metal-clad conductor layer 13a is removed together with the two metal-clad conductor layers 13a and 13b, so that the heights of the copper-clad layer 15 and the copper layer 12a are substantially the same, and the problem that the plating layer overflows the hole 20 and forms a protrusion around the hole 20 during the plating of the hole 20 is avoided, thereby affecting the manufacturing of the circuit board structure 100. In addition, because the metal conductor has conductivity, the metallized layer 14 can be adsorbed on average in the metallization process, and the problem that the metallized layer 14 is adsorbed on average by using the photoresist in the traditional process is solved. In addition, the photoresist has no alkali resistance effect, and can be metallized only by a neutral or weak acid metallization system, while the metal-clad conductor layers 13a and 13b are not limited by the neutral or weak acid metallization system, and an alkaline metallization system can be selected, so that the manufacturing efficiency of the circuit board structure 100 is improved, and the multiple elements of the manufacturing method are increased. The metal conductor layers 13a and 13b are covered on the two copper layers 12a and 12b by chemical deposition or electroplating, the thickness is not limited by the manufacturing thickness of the photoresist, and the metal conductor is conductive, so that the action in the electroplating process is changed from the traditional pattern electroplating to the whole plate electroplating, the overall electroplating uniformity is easier to control than the pattern electroplating, and the phenomenon that the electroplating on the metal conductor is difficult to remove due to the overlarge thickness difference is avoided when the electroplating layer on the metal conductor is removed later.

In the first embodiment, the pattern of each subsequent circuit can be continuously manufactured through the completed circuit board structure. Fig. 7a is a schematic diagram (eight) of a circuit board structure manufacturing method according to a first embodiment. Fig. 7b is a schematic diagram (nine) of a circuit board structure manufacturing method according to a first embodiment. Fig. 12 is a flowchart (ii) of a method for manufacturing a circuit board structure according to a first embodiment. As shown in fig. 7a, 7b and 12, the two photoresist layers 16 are covered on the surfaces of the two copper layers 12a and 12b, and the two photoresist layers 16 are exposed and developed to form a circuit pattern structure 161 (step S17). An etching process is performed to remove the surfaces of the copper layers 12a, 12b not covered by the photoresist layers 16 (step S18). Then, the two photoresist layers 16 are removed (step S19), so as to complete the circuit pattern of the circuit board structure 100. In the first embodiment, the photoresist layer 16 may be, for example, a dry film photoresist or a wet film photoresist.

Further, please refer to fig. 7c. Fig. 7c is a schematic diagram of a copper-clad structure of a circuit board structure manufacturing method according to another aspect of the first embodiment (ii). Continuing with the description of fig. 6b, the circuit board structure 100 completed by removing the copper-clad layer 15 partially exceeding the height of the copper layer 12a on the side of the first surface 111 to be aligned with the metal-clad conductor layer 13a and removing the two metal-clad conductor layers 13a, 13b will be formed in a form of slightly higher copper-clad layer 15 than the copper layer 12a in fig. 7c when the circuit pattern is subsequently fabricated.

Next, please refer to fig. 8, 9 and 10. Fig. 8 is a schematic diagram (a) of a circuit board structure manufacturing method according to a second embodiment. Fig. 9 is a schematic diagram (ii) of a circuit board structure manufacturing method according to a second embodiment. Fig. 10 is a schematic diagram (iii) of a circuit board structure manufacturing method according to a second embodiment. In the second embodiment, at least one hole 30 is formed through the substrate 10. The same portions as those in the first embodiment will not be described again, and only the differences will be described. As shown in fig. 8, the hole 30 is formed by mechanical drilling, punching or laser drilling, and the hole 30 sequentially passes through the metal-clad conductor layer 13a, the copper layer 12a, the base material layer 11, the copper layer 12b, and the metal-clad conductor layer 13b from the metal-clad conductor layer 13a on the side of the first surface 111 to the metal-clad conductor layer 13b on the side of the second surface 112. The hole 30 includes a hole wall 31, and the hole wall 31 includes a metal-clad conductor layer 13a, a copper layer 12a, a base material layer 11, a copper layer 12b, and side surfaces of the metal-clad conductor layer 13b exposed by drilling. The metallization layer 14 covers the surface of the hole 30, the surface of the metal-clad conductor layer 13a on the side of the first surface 111, and the surface of the metal-clad conductor layer 13b on the side of the second surface 112. Generally, the coverage of metallization layer 14 does not include portions of copper, such as the side surfaces of copper layer 12a exposed by the borehole and the side surfaces of copper layer 12b exposed by the borehole. As shown in fig. 9, during the electroplating stage, the copper-clad layer 15 covers the surface of the hole 30 and extends to the surface of the metal-clad conductor layer 13a on the side of the first surface 111 and the surface of the metal-clad conductor layer 13b on the side of the second surface 112. As shown in fig. 10, the copper-clad layer 15 partially exceeding the height of the copper layer 12a on the side of the first surface 111 and the copper-clad layer 15 partially exceeding the height of the copper layer 12b on the side of the second surface 112 are then removed by chemical etching. After removing the metal-clad conductor layers 13a and 13b, the substrate 10 is completed, as shown in fig. 10, with the copper-clad layer 15 filling the hole 30 (through hole).

In summary, according to the method for manufacturing the circuit board structure 100 of the embodiment, the metallization and electroplating range is increased by the two metal-clad conductor layers 13a and 13b, and when the electroplating process is performed, the copper-clad layer 15 extends to the surface of the metal-clad conductor layer 13a, and then the copper-clad layer 15 exceeding the height range of the metal-clad conductor layer 13a and the two metal-clad conductor layers 13a and 13b are removed together, so that the heights of the copper-clad layer 15 and the copper layer 12a are approximately consistent, and the overflow of the electroplating layer from the hole is avoided when the electroplating hole is performed, and the protruding portion is formed around the hole, thereby affecting the manufacturing of the circuit board structure 100. In addition, since the metal conductor has conductivity, the electric requirement during electroplating can be satisfied without depending on the adsorption effect of the metallization system, and the metal conductor layers 13a and 13b are not limited to neutral or weak acid metallization systems, and alkaline metallization systems can be selected, so that the manufacturing efficiency of the circuit board structure 100 is improved and the multiple properties of the manufacturing method are increased. The metal conductor layers 13a and 13b are covered on the two copper layers 12a and 12b by chemical deposition, sputtering or electroplating, the thickness is not limited by the manufacturing thickness of the photoresist, and the property of the conventional pattern plating is changed into the whole plate plating due to the conductivity of the material of the metal conductor in the electroplating process, so that the overall plating uniformity is easier to control than that of the pattern plating, and the phenomenon that the plating layer on the metal conductor is difficult to remove due to the overlarge thickness difference is avoided when the plating layer on the metal conductor is removed later.

Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention, as will be apparent to those skilled in the art, without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method of manufacturing a circuit board structure, comprising:

providing a substrate, wherein the substrate comprises a substrate layer and two copper layers, the substrate layer is provided with a first surface and a second surface which are opposite, and each copper layer is formed on the first surface and the second surface of the substrate layer;

forming two metal-clad conductor layers through chemical plating, sputtering or electroplating, wherein the two metal-clad conductor layers are respectively covered on the surfaces of the two copper layers;

drilling from the surface of the metal-clad conductor layer at one side of the first surface to form at least one hole, wherein the at least one hole is communicated with the copper layer exposed at the second surface of the substrate layer;

forming a metallization layer by a chemical mode, wherein the metallization layer covers the surface of the at least one hole and the surfaces of the two metal-coated conductor layers;

forming a copper-clad layer by electroplating, wherein the copper-clad layer covers the surface of the at least one hole and extends to the surface of the metal-clad conductor layer positioned on one side of the first surface, and covers the surface of the metal-clad conductor layer on one side of the second surface;

removing a portion of the copper-clad layer that exceeds the height of the copper layer by chemical etching; and

the metal-clad conductor layer is removed by chemical etching.

2. The method of claim 1, wherein each of the metal-clad conductor layers is chromium, nickel, aluminum, titanium, tin, platinum, gold, or silver.

3. The method of claim 1, wherein the copper-clad layer passing through the at least one hole connects the two copper layers.

4. The method of claim 1, wherein the at least one hole is routed to the metal-clad conductor layer on one side of the second surface during drilling.

5. The method of manufacturing a circuit-board structure according to claim 1, wherein the copper-clad layer is aligned with the height of the copper layer by chemical etching during removal of the copper-clad layer partially exceeding the height of the copper layer by chemical etching.

6. The method of claim 1, wherein the at least one hole is formed by laser drilling, mechanical drilling or punching.

7. The method of manufacturing a circuit board structure according to claim 1, wherein the thickness of the metal-clad conductor layer is 0.1 to 20 μm.

8. The method of manufacturing a circuit board structure according to claim 1, after removing the metal-clad conductor layer by chemical etching;

covering two photoresist layers on the surfaces of the two copper layers, and exposing and developing the two photoresist layers to form a circuit pattern structure;

etching to remove the surface of each copper layer uncovered by each photoresist layer; and

the two photoresist layers are removed.

9. A circuit board structure manufactured by the method of manufacturing a circuit board structure according to any one of claims 1 to 8.