阅读说明：本技术 一种印制线路板及其制作方法 (Printed circuit board and manufacturing method thereof ) 是由 梁梦楠 刘海龙 蒋忠明 吴杰 付强 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种印制线路板及其制作方法,其中,印制线路板的制作方法包括：获取待加工板件,对待加工板件进行棕化,以在待加工板件上形成棕化膜；对棕化膜进行减薄,形成减薄后的棕化膜；将形成有减薄后的棕化膜的待加工板件进行后处理,获得具有盲孔的印制线路板；通过上述方式,本发明的印制线路板的制作方法通过对棕化膜进行减薄,以减少去钻污过程中药水对棕化膜的侵蚀作用,从而减小楔形裂缝的宽度,最终达到在保持板件不会发生分层等可靠性问题的前提下减小楔形裂纹缺陷。(The invention discloses a printed circuit board and a manufacturing method thereof, wherein the manufacturing method of the printed circuit board comprises the following steps: obtaining a plate to be processed, and performing browning on the plate to be processed to form a browning film on the plate to be processed; thinning the browning membrane to form a thinned browning membrane; carrying out post-treatment on the plate to be processed with the thinned browning film to obtain a printed circuit board with a blind hole; through the mode, the manufacturing method of the printed circuit board reduces the erosion effect of the liquid medicine on the browning film in the drilling dirt removing process by thinning the browning film, so that the width of the wedge-shaped crack is reduced, and finally the defect of the wedge-shaped crack is reduced on the premise of keeping the reliability problems of layering and the like of the plate.)

1. A manufacturing method of a printed circuit board is characterized by comprising the following steps:

obtaining a plate to be processed, and carrying out browning on the plate to be processed so as to form a browning membrane on the plate to be processed;

thinning the browning membrane to form a thinned browning membrane;

and carrying out post-treatment on the plate to be processed on which the thinned browning film is formed to obtain the printed circuit board with the blind hole.

2. The method according to claim 1, wherein the step of thinning the browning membrane and forming the thinned browning membrane comprises:

and carrying out alkali washing treatment on the browning membrane for a preset time through an alkaline solution with a preset concentration at a preset temperature to form the thinned browning membrane.

3. The method of manufacturing a printed wiring board according to claim 2,

the preset temperature range is 20-35 ℃, and the alkaline solution with the preset concentration is a sodium hydroxide solution with the mass fraction range of 0.4-1.0%; the preset time ranges from 15 seconds to 35 seconds.

4. The method for manufacturing a printed wiring board according to any one of claims 1 to 3, wherein the thinned brownification film has a thickness in a range of 18 to 22 nm.

5. The method for manufacturing the printed wiring board according to claim 1, wherein the step of performing post-treatment on the board to be processed on which the thinned browning film is formed to obtain the printed wiring board with the blind hole comprises:

pressing the plate to be processed with the thinned browning membrane;

manufacturing the blind hole on the pressed plate to be processed through laser drilling;

and metalizing the blind holes to obtain the printed circuit board with the metalized blind holes.

6. The method for manufacturing the printed wiring board according to claim 5, wherein the step of manufacturing the blind hole on the pressed board to be processed by laser drilling comprises:

laser drilling light spots are overlapped and ablated on a preset position of the pressed plate to be processed through laser drilling, so that the blind hole is manufactured on the preset position;

and performing drilling dirt removal treatment on the blind hole.

7. The method according to claim 5, wherein the step of metalizing the blind via to obtain the printed wiring board with metalized blind via comprises:

and metalizing the blind holes through electroplating or sputtering to obtain the printed circuit board with the metalized blind holes.

8. The method for manufacturing the printed wiring board according to claim 1, wherein the step of obtaining the board to be processed, and performing browning on the board to be processed to form a browning film on the board to be processed comprises:

pickling the first plate to remove oxides on the first plate;

and carrying out alkali washing on the first plate to remove stains such as oil stains, impurities and the like on the first plate, so as to obtain the plate to be processed.

9. The method of claim 1, wherein the thickness of the browning film is in a range of 170 nm and 230 nm.

10. A printed wiring board produced by the method for producing a printed wiring board according to any one of claims 1 to 9.

Technical Field

The invention is applied to the technical field of printed circuit boards, in particular to a printed circuit board and a manufacturing method thereof.

Background

Browning techniques are often required to improve the bonding force inside the board during the production of pcb (printed Circuit board) printed wiring boards. Concretely, the browning technique carries out the copper face through browning liquid medicine to the plate and handles to generate the even coarse oxide layer of one deck on the copper foil surface of plate, promote the plate when the pressfitting the cohesion between copper foil and the polymeric material, thereby avoid the plate layering or explode the board scheduling problem to appear. Common browning techniques include black oxidation and brown oxidation.

Currently, with the development of 5G, HDI technology is increasingly applied to printed circuit boards. In the HDI technology, the reliability of a blind hole is particularly critical, and a wedge-shaped crack at the bottom of the blind hole is a main defect in the HDI printed circuit board. The blind hole wedge-shaped crack is a crack between resin at the bottom of a blind hole and copper at the bottom of the blind hole, and when the size of the wedge-shaped crack is too large or the distance between blind holes is too small, a layering phenomenon can be caused, so that the existence of the wedge-shaped crack seriously influences the reliability of the blind hole.

The direct reason for the formation of wedge-shaped cracks in blind holes is that brown films at the bottoms of the blind holes are not resistant to attack by liquid medicine in the drilling process. During the process of removing drilling dirt of the blind hole, the corrosion of the chemical liquid to the browning film causes the formation of a large crack at the bottom of the blind hole, and during the process of metallizing the hole, the electroplating is not enough to fill the large crack, and finally the formation of wedge-shaped crack defects of the blind hole is caused.

Disclosure of Invention

The invention provides a printed circuit board and a manufacturing method thereof, which aim to solve the problems that a large crack exists at the bottom of a blind hole in the prior art, which easily causes the delamination of a plate and the like.

In order to solve the technical problem, the invention provides a method for manufacturing a printed circuit board, which comprises the following steps: obtaining a plate to be processed, and performing browning on the plate to be processed to form a browning film on the plate to be processed; thinning the browning membrane to form a thinned browning membrane; and carrying out post-treatment on the plate to be processed with the thinned browning film to obtain the printed circuit board with the blind hole.

Wherein, thinning the browning membrane, the step of forming thinned browning membrane includes: and carrying out alkali washing treatment on the browning membrane for a preset time through an alkaline solution with a preset concentration at a preset temperature to form the thinned browning membrane.

Wherein the preset temperature range is 20-35 ℃, and the alkaline solution with the preset concentration is a sodium hydroxide solution with the mass fraction range of 0.4-1.0%; the preset time ranges from 15 to 35 seconds.

Wherein the thickness range of the thinned browning film is 18-22 nanometers.

Wherein, the plate to be processed with the brownification membrane after thinning is subjected to post-treatment, and the step of obtaining the printed circuit board with the blind hole comprises the following steps: pressing the plate to be processed with the thinned browning film; manufacturing blind holes in the pressed plates to be processed through laser drilling; and metalizing the blind holes to obtain the printed circuit board with the metalized blind holes.

Wherein, the step of producing the blind hole on waiting to process the plate after the pressfitting through laser drilling includes: laser drilling light spots are overlapped and ablated at a preset position of the pressed plate to be processed through laser drilling, so that a blind hole is manufactured at the preset position; and performing drilling dirt removal treatment on the blind hole.

The step of obtaining the printed circuit board with the metallized blind holes comprises the following steps: and (4) metalizing the blind holes through electroplating or sputtering to obtain the printed circuit board with the metalized blind holes.

Wherein, acquire and treat the processing plate, treat and process the plate and carry out the brown ization to the step before forming brown oxide membrane on treating the processing plate includes: pickling the first plate to remove oxides on the first plate; and (3) carrying out alkali washing on the first plate to remove oil stains, impurities and other stains on the first plate, and obtaining the plate to be processed.

Wherein, the thickness range of the browning membrane is 170-230 nm.

In order to solve the technical problem, the invention also provides a printed circuit board which is prepared by any one of the manufacturing methods of the printed circuit board.

The invention has the beneficial effects that: different from the situation of the prior art, the manufacturing method of the printed circuit board adopted by the invention comprises the following steps: obtaining a plate to be processed, and performing browning on the plate to be processed to form a browning film on the plate to be processed; thinning the browning membrane to form a thinned browning membrane; and carrying out post-treatment on the plate to be processed with the thinned browning film to obtain the printed circuit board with the blind hole. According to the invention, the brownification membrane is thinned, so that the brownification membrane thinned to a certain extent can be obtained while the bonding force between the plates is ensured, the size of cracks generated by impact of the drilling-stain-removing liquid medicine on the thinned brownification membrane is further reduced, and the phenomenon of layering of the plates due to overlarge cracks is reduced.

Drawings

Fig. 1 is a schematic flow chart of an embodiment of a method for manufacturing a printed wiring board according to the present invention;

FIG. 2 is a schematic flow chart of another embodiment of a method for manufacturing a printed circuit board according to the present invention;

fig. 3 is a schematic structural diagram of an embodiment of a printed wiring board provided by the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a method for manufacturing a printed circuit board according to the present invention. The method for manufacturing the printed circuit board comprises the following steps:

s11: obtaining a plate to be processed, and carrying out browning on the plate to be processed so as to form a browning film on the plate to be processed.

Obtaining a plate to be processed, and carrying out browning on the plate to be processed by browning chemical liquid so as to form a layer of extremely thin uniform organic metal conversion film on the surface of a copper layer of the plate to be processed, wherein the layer of organic metal conversion film is a browning film. A layer of browning film is generated on the surface of the plate to be processed, so that the binding force between a copper layer and epoxy resin can be improved when the multilayer circuit board is pressed.

S12: and thinning the browning membrane to form the thinned browning membrane.

The brownification film is an organic metal complex and is not attacked by corrosive liquid medicine such as acid and alkali. In the subsequent process of removing drilling dirt from the blind holes of the printed circuit board, the corrosion of drilling dirt removing liquid medicine on the browning film leads to the formation of large cracks at the bottoms of the blind holes, and in the process of metallizing the holes, electroplating is not enough to fill the large cracks, and finally the formation of wedge-shaped crack defects of the blind holes is easy to cause.

In this step, carry out the attenuate to brown oxide membrane through alkaline liquid medicine under certain condition, form brown oxide membrane after the attenuate for brown oxide membrane's thickness has obtained the attenuate to a certain extent, guarantees simultaneously that brown oxide membrane after the attenuate is even unanimous structure not destroyed, still possesses enough and stable cohesion. In addition, although the browning membrane can react with the acidic solution to reduce the thickness of the browning membrane, the use of the acidic solution cannot ensure a uniform structure of the browning membrane, and it is difficult to make the thinned browning membrane still have stable binding force. Therefore, in this embodiment, an alkaline chemical is selected to thin the browning membrane.

S13: and carrying out post-treatment on the plate to be processed with the thinned browning film to obtain the printed circuit board with the blind hole.

And pressing the plate to be processed to form the multilayer circuit board after the thinned browning film is formed on the plate to be processed. And drilling a hole on the multilayer circuit board to drill at least one blind hole, wherein the at least one blind hole penetrates through the epoxy resin and the thinned browning film to conduct between layers of the multilayer circuit board. When the drilling dirt is removed from the blind hole through the drilling dirt removing liquid medicine, the erosion degree of the thinned browning membrane is reduced by the drilling dirt removing liquid medicine, so that the generated wedge-shaped cracks are reduced to a certain degree, and the phenomenon that the printed circuit board is easily layered due to the overlarge wedge-shaped cracks is reduced.

In this way, this embodiment is through under the prerequisite that does not change current process flow, carries out the attenuate to a certain extent with brown oxide membrane to keep the stable cohesion of brown oxide membrane after the attenuate, with when guaranteeing the cohesion between multilayer circuit board layer and the layer, reduce blind hole wedge crack defect effectively, reduce the phenomenon that the plate appears layering because of the crack is too big. The reliability of the multilayer circuit board with the blind holes is guaranteed, and the quality of the multilayer circuit board is improved.

Referring to fig. 2, fig. 2 is a schematic flow chart of another embodiment of a method for manufacturing a printed circuit board according to the present invention, in this embodiment, the printed circuit board is a multilayer circuit board having blind holes. The method for manufacturing the printed circuit board comprises the following steps:

s21: and (3) carrying out acid cleaning on the first plate to remove oxides on the first plate, and carrying out alkali cleaning on the first plate to remove stains such as oil stains, impurities and the like on the first plate to obtain the plate to be processed.

And obtaining a first plate, and pickling the first plate to remove oxides and dirt on the surface of the first plate. And after acid washing, performing alkali washing on the first plate to remove stains such as oil stains, impurities and the like on the first plate, and thus obtaining the plate to be processed. And an alkaline environment is created on the plate surface of the plate to be processed, so that the plate can be browned by the brownification liquid medicine.

Various stains on the surface of the plate are cleaned and removed, certain cleanliness is guaranteed before the plate enters the browning tank, the phenomenon that the stains pollute the browning tank in the plate browning process is reduced, and meanwhile, the browning effect of the plate is guaranteed to a certain extent.

S22: obtaining a plate to be processed, and carrying out browning on the plate to be processed so as to form a browning film on the plate to be processed.

Obtaining a plate to be processed with certain cleanliness, and browning the plate to be processed by browning chemical liquid so as to form a layer of extremely thin uniform organic metal conversion film on the surface of a copper layer of the plate to be processed, wherein the layer of organic metal conversion film is a browning film. A layer of browning film is generated on the surface of the plate to be processed, so that the binding force between a copper layer and epoxy resin can be improved when the multilayer circuit board is pressed.

Wherein the thickness range of the brown oxide film is 170-230 nm. The browning membrane within the thickness range can provide enough stable binding force for plate combination, but the browning membrane cannot resist the erosion of drilling dirt removing chemicals in the subsequent drilling dirt removing process, cracks with the width range of 170-230 nm are easily formed at the bottom of the blind hole, and the cracks within the width range are very easy to cause the phenomenon of layering of the multilayer circuit board.

S23: and carrying out alkali washing treatment on the browning membrane for a preset time through an alkaline solution with a preset concentration at a preset temperature to form the thinned browning membrane.

Performing alkali washing treatment on the browning membrane for a preset time through an alkaline solution with a preset concentration at a preset temperature to form a thinned browning membrane, wherein the preset temperature range is 20-35 ℃, and the alkaline solution with the preset concentration is a sodium hydroxide solution with a mass fraction range of 0.4-1.0%; the preset time ranges from 15 to 35 seconds. When the thinning treatment meets the above conditions, the thickness of the brown oxide film can be effectively thinned, the structure of the brown oxide film is kept from being damaged, and a certain binding force is still provided. At the moment, the thickness of the thinned browning film is in the range of 18-22 nanometers. The thickness of the browning membrane is effectively reduced.

Alternatively, a browning membrane in the range of 170 and 230 nm thickness was treated at 30 degrees celsius for 25 seconds using 0.7% by mass sodium hydroxide solution. The brown oxide film can be thinned to about 20 nanometers, and the structure of the thinned brown oxide film is not damaged. The thinned browning film can have enough bonding effect, so that the plate is free from the reliability problems such as delamination and the like. The 0.4-1.0% by mass fraction sodium hydroxide solution of this example can be replaced with an alkaline solution containing other alkaline substances as well, but the concentration of hydroxide needs to be the same as that of hydroxide in a sodium hydroxide solution having a mass fraction in the range of 0.4-1.0%.

In this step, carry out the attenuate to brown oxide membrane through alkaline liquid medicine under certain condition, form brown oxide membrane after the attenuate for brown oxide membrane's thickness has obtained the attenuate to a certain extent, guarantees simultaneously that brown oxide membrane after the attenuate is even unanimous structure not destroyed, still possesses enough and stable cohesion. In addition, although the browning membrane can react with the acidic solution to reduce the thickness of the browning membrane, the use of the acidic solution cannot ensure a uniform structure of the browning membrane, and it is difficult to make the thinned browning membrane still have stable binding force. Therefore, in this embodiment, an alkaline chemical is selected to thin the browning membrane.

S24: and pressing the plate to be processed with the thinned browning membrane, manufacturing a blind hole on the pressed plate to be processed through a laser hole, and metalizing the blind hole to obtain the printed circuit board with the metalized blind hole.

And pressing the plate to be processed to form the multilayer circuit board after the thinned browning film is formed on the plate to be processed.

And laser drilling facula superposition ablation is carried out at the preset position of the plate to be processed after the pressing by a carbon dioxide laser drilling machine so as to drill and burn at least one blind hole at the preset position, and the plate to be processed after the pressing is communicated with each other.

The plate has gluey sediment to remain after laser beam bores the ablation, in this embodiment, uses to remove to bore dirty liquid medicine and removes to bore dirty the processing to the plate, lets the plate carry out "swelling" through removing to bore dirty liquid medicine to make the remaining gluey sediment behind the laser beam ablation plate break away from step groove bottom copper sheet. In the process, as the browning membrane between the multilayer circuit boards is thinned, the thickness of the browning membrane ranges from 18 nanometers to 22 nanometers, the erosion thickness range of the drilling pollutant removal liquid medicine is reduced to a certain extent, and the drilling pollutant removal liquid medicine is difficult to enter the inside of the browning membrane through the opening between the bottom of the blind hole and the browning membrane due to the reduction of the thickness of the thinned browning membrane. Therefore, the length and the thickness of the wedge-shaped crack of the embodiment are reduced to a certain extent, so that the phenomenon of plate delamination caused by the wedge-shaped crack defect is reduced.

And metalizing the at least one blind hole by electroplating or sputtering so as to conduct the layers of the printed circuit board.

The embodiment treats the browning membrane through the process parameters in a specific range, so that the browning membrane can keep the original effect, the erosion of the drilling-stain-removing liquid medicine to the browning membrane in the subsequent process can be reduced by thinning the browning membrane, and the purpose of reducing the wedge-shaped crack defect is finally achieved. Thereby reducing the problem of panel delamination due to wedge cracks.

Referring to fig. 3, fig. 3 is a schematic structural diagram of an embodiment of a printed wiring board provided in the present invention. The printed wiring board of this embodiment is a two-layer wiring board, and in other embodiments, the printed wiring board may be a multilayer wiring board, such as 4-layer, 5-layer, etc.

The printed wiring board 10 of the present embodiment includes: a first copper layer 11, a first insulating layer 12, a brown oxide film 13, a second copper layer 14, and a second insulating layer 15. The first copper layer 11, the first insulating layer 12, the browning film 13, the second copper layer 14 and the second insulating layer 15 are sequentially attached to form the printed wiring board 10. The printed circuit board 10 is provided with a blind metallized hole 16, and the blind metallized hole 16 penetrates through the first copper layer 11, the first insulating layer 12 and the browning film 13, and is attached to and contacted with the second copper layer 14 to conduct the first copper layer 11 and the second copper layer 14. A crack 17 is formed between the browning membrane 13 and the blind metallized hole 16. Wherein the width of the slit 17 is 20 nm. In the present embodiment, the filling metal of the metallized blind via 16 is copper, and in other embodiments, the material of the filling metal can be other conductive metals.

The slits 17 having a width of only 20 nm can reduce the occurrence of delamination of the board due to an excessively large gap in the printed wiring board 10. Meanwhile, the browning membrane 13 can also keep a uniform structure to provide enough bonding force to enable the circuit boards to be stably and durably bonded together.

The printed circuit board of this embodiment reduces blind hole wedge crack under the prerequisite that guarantees that original brown oxide membrane structure can play the effect that bonds and makes the plate reliability problems such as layering not take place, avoids the wedge crack defect because of brown oxide membrane too thick leads to effectively. The phenomenon that the printed circuit board is easy to delaminate due to the existence of wedge-shaped cracks is reduced, and the reliability and the quality of the printed circuit board are improved.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.