阅读说明：本技术 印刷电路板的表面处理方法及印刷电路板 (Surface treatment method of printed circuit board and printed circuit board ) 是由 张佳 马奕 胡新星 叶卓炜 于 2021-08-18 设计创作，主要内容包括：本发明适用于印刷电路板技术领域,提出一种印刷电路板的表面处理方法,包括：提供印刷电路板；将UV减粘胶带贴于所述印刷电路板的表面,所述UV减粘胶带具有开窗部；对所述印刷电路板上与所述开窗部对应的部分表面进行沉镍金处理,以形成镍金保护层；对所述印刷电路板照射UV光或进行等离子处理,使所述UV减粘胶带的剥离强度降低,以撕除所述UV减粘胶带。本发明还提出一种印刷电路板。上述印刷电路板的表面处理方法成本较低、效率较高、适用范围广,表面处理后的印刷电路板具有较好的品质。(The invention is suitable for the technical field of printed circuit boards, and provides a surface treatment method of a printed circuit board, which comprises the following steps: providing a printed circuit board; attaching a UV (ultraviolet) adhesive reduction tape to the surface of the printed circuit board, wherein the UV adhesive reduction tape is provided with an opening part; performing nickel-gold immersion treatment on the partial surface of the printed circuit board corresponding to the windowing part to form a nickel-gold protective layer; and irradiating UV light or carrying out plasma treatment on the printed circuit board to reduce the peeling strength of the UV adhesive tape so as to tear off the UV adhesive tape. The invention also provides a printed circuit board. The surface treatment method of the printed circuit board has the advantages of low cost, high efficiency and wide application range, and the printed circuit board after surface treatment has good quality.)

1. A surface treatment method of a printed circuit board, comprising:

providing a printed circuit board;

attaching a UV (ultraviolet) adhesive reduction tape to the surface of the printed circuit board, wherein the UV adhesive reduction tape is provided with an opening part;

performing nickel-gold immersion treatment on the partial surface of the printed circuit board corresponding to the windowing part to form a nickel-gold protective layer;

and irradiating UV light or carrying out plasma treatment on the printed circuit board to reduce the peeling strength of the UV adhesive tape so as to tear off the UV adhesive tape.

2. The surface treatment method of a printed circuit board according to claim 1, wherein attaching a UV detackifying tape to the surface of the printed circuit board comprises:

cutting the UV viscosity-reducing adhesive material to obtain a UV viscosity-reducing adhesive tape matched with the size of the printed circuit board;

processing a first positioning hole on the UV viscosity reducing adhesive tape, wherein the first positioning hole is arranged corresponding to a second positioning hole on the printed circuit board;

removing a partial area corresponding to the nickel and gold deposition area of the printed circuit board on the UV reduction adhesive tape to process the windowing part;

and sticking the UV adhesive-reducing tape on the surface of the printed circuit board through a positioning jig.

3. The surface treatment method of a printed circuit board according to claim 2,

processing the first positioning hole in a punching, mechanical drilling or laser drilling mode;

the window opening part is processed in a milling and routing forming mode, a punching forming mode or a laser cutting forming mode.

4. The surface treatment method of a printed circuit board according to claim 2, wherein the positioning jig comprises a jig plate provided with a plurality of through holes and positioning pins inserted in the through holes;

will through positioning jig UV subtracts sticky tape paste in printed circuit board's surface includes:

placing the upper surface of the printed circuit board on the jig board upwards to enable the positioning pin to penetrate through the second positioning hole;

placing the UV anti-sticking adhesive tape on the positioning jig, enabling the positioning needle to simultaneously penetrate through the corresponding second positioning hole and the corresponding first positioning hole, and enabling the UV anti-sticking adhesive tape to be attached to the upper surface of the printed circuit board;

adjusting the positioning pin, and placing the lower surface of the printed circuit board on the jig board in an upward manner to enable the positioning pin to penetrate through the second positioning hole;

and attaching another UV (ultraviolet) adhesive reduction tape to the lower surface of the printed circuit board.

5. The surface treatment method of a printed circuit board according to claim 4, wherein after attaching another UV detackifying tape to the lower surface of the printed circuit board, the surface treatment method further comprises:

and (3) enabling the printed circuit board to pass through a film sticking machine, wherein the temperature of a roller of the film sticking machine is 110-130 ℃, and the peeling strength of the UV viscose glue is increased.

6. The surface treatment method of a printed circuit board according to claim 1, wherein the UV anti-adhesive tape comprises a PET film, a UV anti-adhesive layer and a release film, which are sequentially stacked, wherein the thickness of the PET film is 20um to 30um, the thickness of the UV anti-adhesive layer is 17um to 23um, and the thickness of the release film is 0.1um to 1 um.

7. The surface treatment method of a printed circuit board according to claim 6, wherein the peel strength of the UV visbreaker layer in a normal temperature state is 10gf/25mm to 15gf/25 mm; the peel strength of the UV visbreaking adhesive layer after UV light irradiation or plasma treatment is less than 5gf/25 mm.

8. The surface treatment method of a printed circuit board according to any one of claims 1 to 7, wherein the printed circuit board is passed through a UV machine or a plasma machine to irradiate UV light to the printed circuit board or to perform plasma treatment;

the parameters of the plasma machine are as follows: a stage of treatment, wherein the temperature rise time is 55-65min, the power is 6.5-7.5 KW, the temperature is 75-85 ℃, and the pressure is 200-300 mTorr; two-stage treatment, the holding time is 12-15min, the power is 4.5-5.5 KW, the temperature is 80-90 ℃, and the pressure is 200-300 mTorr; three-stage treatment, wherein the holding time is 1-2min, the power is 5.5-6.5 KW, the temperature is 85-95 ℃, and the pressure is 200-300 mTorr;

the plate passing energy of the UV machine is greater than or equal to 300 mJ.

9. The surface treatment method of a printed circuit board according to any one of claims 1 to 7, further comprising, after the UV adhesive tape is peeled off:

and carrying out OSP (organic solderability preservative) antioxidation treatment on the surface area of the printed circuit board without the nickel-gold protective layer.

10. A printed circuit board characterized by being treated by the surface treatment method of a printed circuit board according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of printed circuit boards, in particular to a surface treatment method of a printed circuit board and the printed circuit board.

Background

The selective chemical immersion nickel gold is prepared by adopting a chemical immersion nickel gold process to prepare a nickel gold protective layer on the surface of a part of copper layer on the outermost layer of a Printed Circuit Board (PCB) which is not covered by solder resist, and adopting other surface treatment modes in other areas, most commonly adopting an anti-oxidation process to prepare an Organic solder mask (OSP).

When the selective product is manufactured, two different surface treatments are required to be manufactured on the outer copper surface of the same PCB, a dry film or a wet film is usually selected to protect the copper surface which does not need to be selected, the dry film/wet film is removed after the selection is finished, and then another surface treatment is performed. However, the dry film needs to be a high temperature resistant dry film, which is relatively high in cost, and when other types of dry films which are not high temperature resistant are selected, wrinkling and foaming can occur in the selecting process, so that the manufacturing quality is affected; the wet film is not suitable for the PCB with multiple through holes, the application range is narrow, and the PCB with few through holes needs to be sealed by adhesive tapes to carry out surface treatment, so that manpower and material resources are wasted. In addition, no matter the film is a dry film or a wet film, when the film is removed, the risk of incomplete film removal exists, and the quality of the PCB is influenced.

Disclosure of Invention

The invention provides a surface treatment method of a printed circuit board and the printed circuit board, which can solve the problems of wrinkling and bubbling, higher cost, narrow application range and poor quality in a selection process.

The embodiment of the invention provides a surface treatment method of a printed circuit board, which comprises the following steps:

providing a printed circuit board;

attaching a UV (ultraviolet) adhesive reduction tape to the surface of the printed circuit board, wherein the UV adhesive reduction tape is provided with an opening part;

performing nickel-gold immersion treatment on the partial surface of the printed circuit board corresponding to the windowing part to form a nickel-gold protective layer;

and irradiating UV light or carrying out plasma treatment on the printed circuit board to reduce the peeling strength of the UV adhesive tape so as to tear off the UV adhesive tape.

In one embodiment, attaching UV anti-adhesive tape to a surface of the printed circuit board includes:

cutting the UV viscosity-reducing adhesive material to obtain a UV viscosity-reducing adhesive tape matched with the size of the printed circuit board;

processing a first positioning hole on the UV viscosity reducing adhesive tape, wherein the first positioning hole is arranged corresponding to a second positioning hole on the printed circuit board;

removing a partial area corresponding to the nickel and gold deposition area of the printed circuit board on the UV reduction adhesive tape to process the windowing part;

and sticking the UV adhesive-reducing tape on the surface of the printed circuit board through a positioning jig.

In one embodiment, the first positioning hole is processed by punching, mechanical drilling or laser drilling;

the window opening part is processed in a milling and routing forming mode, a punching forming mode or a laser cutting forming mode.

In one embodiment, the positioning jig comprises a jig plate provided with a plurality of through holes and positioning pins inserted in the through holes;

will through positioning jig UV subtracts sticky tape paste in printed circuit board's surface includes:

placing the upper surface of the printed circuit board on the jig board upwards to enable the positioning pin to penetrate through the second positioning hole;

placing the UV anti-sticking adhesive tape on the positioning jig, enabling the positioning needle to simultaneously penetrate through the corresponding second positioning hole and the corresponding first positioning hole, and enabling the UV anti-sticking adhesive tape to be attached to the upper surface of the printed circuit board;

adjusting the positioning pin, and placing the lower surface of the printed circuit board on the jig board in an upward manner to enable the positioning pin to penetrate through the second positioning hole;

and attaching another UV (ultraviolet) adhesive reduction tape to the lower surface of the printed circuit board.

In one embodiment, after attaching another UV detackifying tape to the lower surface of the printed circuit board, the surface treatment method further includes:

and (3) enabling the printed circuit board to pass through a film sticking machine, wherein the temperature of a roller of the film sticking machine is 110-130 ℃, and the peeling strength of the UV viscose glue is increased.

In an embodiment, the UV visbreaking tape comprises a PET film, a UV visbreaking adhesive layer and a release film which are sequentially stacked, wherein the thickness of the PET film is 20um-30um, the thickness of the UV visbreaking adhesive layer is 17um-23um, and the thickness of the release film is 0.1um-1 um.

In one embodiment, the peel strength of the UV visbreaking adhesive layer in a normal temperature state is 10gf/25mm-15gf/25 mm; the peel strength of the UV visbreaking adhesive layer after UV light irradiation or plasma treatment is less than 5gf/25 mm.

In one embodiment, the printed circuit board is passed through a UV machine or a plasma machine to irradiate UV light or perform plasma treatment on the printed circuit board;

the parameters of the plasma machine are as follows: a step of treatment, wherein the temperature rise time is 55-65min, the power is 6.5-7.5 KW, the temperature is 75-85 ℃, and the pressure is 200-300 mTorr; two-stage treatment, the holding time is 12-15min, the power is 4.5-5.5 KW, the temperature is 80-90 ℃, and the pressure is 200-300 mTorr; three-stage treatment, wherein the holding time is 1-2min, the power is 5.5-6.5 KW, the temperature is 85-95 ℃, and the pressure is 200-300 mTorr;

the plate passing energy of the UV machine is greater than or equal to 300 mJ.

In one embodiment, after removing the UV detackifying tape, the surface treatment method further comprises:

and carrying out OSP (organic solderability preservative) antioxidation treatment on the surface area of the printed circuit board without the nickel-gold protective layer.

A second aspect of the present invention provides a printed circuit board treated by the surface treatment method of the printed circuit board according to the first aspect.

According to the surface treatment method of the printed circuit board, the UV anti-sticking adhesive tape is firstly pasted on the circuit board, then the selective treatment can be directly carried out, the exposure and the development are not needed, the flow process is saved, the cost of the UV anti-sticking adhesive tape is far lower than that of a dry film, and the cost is saved; in addition, in the selecting process, the UV viscosity reducing adhesive tape is not easy to wrinkle and bubble, and the influence on the quality of the product is avoided. The surface treatment method does not need hole sealing in advance, and has wide application range and high efficiency; and the risk of incomplete film stripping does not exist, and the product quality is ensured. Therefore, the surface treatment method of the printed circuit board has the advantages of low cost, high efficiency and wide application range, and the printed circuit board after surface treatment has good quality.

The printed circuit board can be selected under the protection of the UV viscosity-reducing adhesive tape, then the UV viscosity-reducing adhesive tape is peeled off after UV light irradiation or plasma treatment, and then other surface treatments are carried out, so that the manufacturing cost is low, the surface treatment efficiency is high, and the printed circuit board has good quality.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a flowchart of a surface treatment method of a printed circuit board according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a UV anti-adhesive tape provided in an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a lower fixture in the positioning fixture according to the embodiment of the present invention;

fig. 4 is a schematic structural diagram of an upper fixture in the positioning fixture according to the embodiment of the present invention;

fig. 5 is a schematic structural diagram of a positioning pin in the positioning fixture according to an embodiment of the present invention;

FIG. 6 is a schematic view of a process in a surface treatment method according to an embodiment of the present invention;

fig. 7 is a second schematic process diagram of the surface treatment method according to the embodiment of the invention.

The designations in the figures mean:

100. a printed circuit board;

200. UV visbreaking tape; 210. a window opening part; 220. a first positioning hole; 230. a PET film; 240. a UV visbreaking adhesive layer;

300. positioning a jig; 310. a lower jig; 311. a first mounting hole; 320. mounting a jig; 321. a second mounting hole; 330. a positioning pin; 331. an installation part; 332. a positioning part.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, which are examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly or indirectly secured to the other element. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element. The terms "upper", "lower", "left", "right", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, are not to be construed as limiting the patent. The terms "first", "second" and "first" are used merely for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "plurality" is two or more unless specifically limited otherwise.

It should be noted that, in the embodiments of the present invention, the same reference numerals are used to denote the same components or parts, and for the same components or parts in the embodiments of the present invention, only one of the components or parts may be labeled with the reference numeral, and it should be understood that the reference numerals are also applicable to other similar components or parts.

To illustrate the technical solution of the present invention, the following description is made with reference to the specific drawings and examples.

Referring to fig. 1, a surface manufacturing method of a printed circuit board according to a first embodiment of the present invention includes the following steps.

Step S110: a printed circuit board is provided.

In an embodiment, the printed circuit board may be a multilayer circuit board, and the step S110 specifically includes: manufacturing an inner layer circuit on the inner layer core board; the inner core board and the outer copper foil are pressed into a whole through the prepreg, and then the printed circuit board is formed through drilling, copper deposition, board electric and outer circuit manufacturing in sequence.

Step S120: and attaching the UV adhesive tape to the surface of the printed circuit board, wherein the UV adhesive tape is provided with an opening part.

Referring to fig. 2, the UV anti-adhesive tape 200 is adapted to the size of the pcb, the window 210 on the UV anti-adhesive tape corresponds to a portion of the pcb that needs to be subjected to nickel-gold deposition, and the rest of the surface area of the pcb is covered and protected by the UV anti-adhesive tape.

The UV anti-adhesive tape 200 has a certain peel strength at normal temperature, is not easily peeled off, and can reduce the peel strength after UV light irradiation or plasma treatment, so as to be easily torn off.

Step S130: the surface of the printed circuit board corresponding to the window 210 is subjected to a nickel-gold deposition process to form a nickel-gold protective layer.

Because the UV adhesive tape 200 has the window 210, when the printed circuit board is subjected to the nickel-gold deposition treatment, the nickel-gold protective layer is formed only in the region corresponding to the window 210, and the rest regions are covered and protected by the UV adhesive tape 200, so that the selective chemical nickel-gold deposition treatment, namely the selective treatment, of the printed circuit board is realized.

Step S140: the printed circuit board is irradiated with UV light or subjected to plasma treatment to reduce the peel strength of the UV detackifying tape 200 to tear off the UV detackifying tape 200.

After the nickel-gold deposition treatment, the peeling strength of the UV anti-adhesive tape 200 is reduced by irradiating UV light or performing plasma treatment on the printed circuit board, so that the UV anti-adhesive tape 200 can be easily torn off, and residues are avoided. Therefore, in the method, the film stripping is simple and convenient, the glue layer can not remain on the board surface, and the subsequent operation is not influenced.

Optionally, after step S140, an OSP oxidation resistant treatment may be performed on a surface area of the printed circuit board where the nickel-gold protective layer is not formed, so as to form an organic solder mask on the surface of the printed circuit board; it is understood that the surface treatment may be selected in other ways according to the requirement to protect the copper layer from oxidation, and the specific treatment is not limited to OSP, for example, the surface treatment may be performed by depositing tin, depositing silver, spraying tin, etc. on the printed circuit board.

According to the surface treatment method of the printed circuit board, the UV adhesive reducing tape 200 is firstly pasted on the circuit board, then the selective treatment can be directly carried out, the exposure and the development are not needed, the flow process is saved, the cost of the UV adhesive reducing tape 200 is far lower than that of a dry film, and the cost is saved; in addition, in the selective process, the UV anti-adhesive tape 200 is not prone to wrinkling and air bubbles, thereby avoiding affecting the quality of the product. The surface treatment method does not need hole sealing in advance, and has wide application range and high efficiency; and the risk of incomplete film stripping does not exist, and the product quality is ensured. Therefore, the surface treatment method of the printed circuit board has the advantages of low cost, high efficiency and wide application range, and the printed circuit board after surface treatment has good quality.

In one embodiment, as shown in fig. 6, the UV adhesive reduction tape 200 includes a PET (polyethylene terephthalate) film 230, a UV adhesive reduction layer 240, and a release film (not shown) stacked in sequence, and when the UV adhesive reduction tape 200 is attached, the release film is removed first, and then the UV adhesive reduction layer is attached to the surface of the printed circuit board.

Optionally, the thickness of the PET film 230 is 20um-30um, for example, the thickness of the PET film 230 is 20um, 22um, 25um, 27um, 30um, etc., and the PET film 230 is used for carrying the UV visbreaking layer. The thickness of the UV vis-breaking adhesive layer 240 is 17um-23um, for example, the thickness of the UV vis-breaking adhesive layer 240 is 17um, 19um, 20um, 21um, 23um, etc., and the UV vis-breaking adhesive layer 240 plays a role of adhesion. The thickness of the release film is 0.1um-1 um. Optionally, the thickness of the UV anti-adhesive tape 200 after the release film is removed can be less than 50um, and the UV anti-adhesive tape can be completely attached to a plate and can be used for most printed circuit boards.

By adopting the technical scheme, the UV adhesive reducing tape 200 is convenient to manufacture and attach, and can effectively protect the surface which does not need to be selected.

In one embodiment, the peel strength of the UV visbreaking layer 240 at normal temperature is 10gf/25mm to 15gf/25 mm; the peel strength of the UV visbreaking adhesive layer 240 after UV light irradiation or plasma treatment is less than 5gf/25 mm. Therefore, the peeling strength of the UV anti-adhesive layer 240 at normal temperature is high, the UV anti-adhesive layer is not easy to fall off in the gold immersion process, and gold immersion in a non-gold immersion area is avoided, so that the requirement of gold immersion can be met; after the UV anti-adhesive layer 240 is irradiated by UV light or treated by plasma, the peel strength is greatly reduced, so that peeling is facilitated, and the board surface is not easily damaged. Further, when the temperature is heated to 90 ℃ or higher, the peel strength of the UV visbreaking adhesive layer increases to 700gf/25mm to 1000gf/25mm, which is similar to the high temperature resistant dry film, and the UV visbreaking adhesive tape 200 can replace the high temperature resistant dry film.

In an embodiment, the step S120 of attaching the UV anti-adhesive tape to the surface of the printed circuit board specifically includes the following steps.

Firstly, the UV anti-adhesive material is cut to obtain the UV anti-adhesive tape 200 matching the size of the printed circuit board.

Secondly, a first positioning hole 220 is processed on the UV anti-adhesive tape 200, and the first positioning hole 220 is arranged corresponding to a second positioning hole on the printed circuit board, so as to facilitate positioning during adhesive tape pasting.

Next, a partial region corresponding to the nickel-gold deposited region of the pcb is removed on the UV-reducing tape 200 to process the window 210.

Then, the UV adhesive reduction tape 200 is attached to the surface of the printed circuit board by the positioning jig.

By adopting the above technical scheme, the UV anti-adhesive tape 200 can be accurately positioned through the first positioning hole 220, and the windowing portion 210 corresponding to the region to be selected of the printed circuit board can be obtained by windowing before the tape is pasted.

Optionally, the first positioning hole 220 is processed by punching, mechanical drilling or laser drilling; the windowing portion 210 is processed by milling, punching or laser cutting. The processing method of the first positioning hole 220 and the windowing portion 210 can be selected according to the requirement, and the flexibility is high.

In an embodiment, referring to fig. 3 to 7, the positioning jig includes a jig plate 300 having a plurality of through holes and positioning pins 330 inserted into the through holes. The jig plate 300 comprises a lower jig 310 and an upper jig 320 which are detachably connected, a plurality of first mounting holes 311 are formed in the lower jig 310, a plurality of second mounting holes 321 are formed in the upper jig 320, the first mounting holes 311 and the second mounting holes 321 are correspondingly arranged, and the diameter of the first mounting holes 311 is larger than that of the second mounting holes 321. The positioning pins 330 are used for simultaneously penetrating into the corresponding first mounting holes 311 and second mounting holes 321. By such design, the position of the positioning pin 330 on the jig board 300 can be flexibly adjusted, and the jig board is suitable for printed circuit boards with different sizes. The positioning pin 330 may include a mounting portion 331 and a positioning portion 332 connected to each other, the mounting portion 331 and the positioning portion 332 are both circular in cross section, the diameter of the mounting portion 331 is greater than that of the positioning portion 332, the mounting portion 331 may be fixed in the first mounting hole 311, and the positioning portion 332 may be disposed on the second mounting hole 321, the UV anti-adhesive tape 200 and the printed circuit board 100 to position the printed circuit board 100 and the UV anti-adhesive tape 200.

The UV anti-sticking adhesive tape 200 is stuck to the surface of the printed circuit board through the positioning jig, and the method specifically comprises the following steps.

First, as shown in fig. 6, the upper surface of the printed circuit board 100 is placed on the jig board 300, and the positioning pin 330 is inserted into the second positioning hole.

Next, the UV anti-adhesive tape 200 is placed on the positioning fixture 300, so that the positioning pins 330 penetrate through the corresponding second positioning holes and the first positioning holes 220, and the UV anti-adhesive tape 200 is attached to the upper surface of the printed circuit board.

Next, the positioning pins are adjusted, and the lower surface of the printed circuit board 100 is placed on the jig board 300 in an upward manner, so that the positioning pins 330 are inserted into the second positioning holes.

Then, another UV anti-adhesive tape 200 is attached to the lower surface of the printed circuit board 100.

Thus, the surface treatment method provided by the embodiment of the invention can respectively attach the UV adhesive tape 200 to the upper surface and the lower surface of the printed circuit board through the positioning jig 300, thereby facilitating the selective treatment of the upper surface and the lower surface; the positioning jig aligns the printed circuit board and the UV adhesive reduction tape 200 through the positioning pins 330, positioning accuracy is high, and surface treatment accuracy and yield are improved.

Further, after the UV anti-adhesive tape 200 is attached to both the upper and lower surfaces of the printed circuit board 100, the surface treatment method further includes: the printed circuit board 100 is passed through a film sticking machine, the temperature of a roller of the film sticking machine is 110-130 ℃, and the peeling strength of the UV anti-adhesive is increased.

Thus, the laminator can ensure that the UV anti-adhesive tape 200 is tightly adhered to the surface of the printed circuit board 100 without generating bubbles and wrinkles; moreover, the temperature of the roller is 110-130 ℃, so that the peel strength of the UV adhesive can be increased, and in the embodiment, the peel strength of the UV adhesive can be increased to 700-1000 gf/25 mm.

Furthermore, the pressure of the upper and lower rollers is 3.5-4.5kg, and the plate passing speed is 2-2.5m/min, so that the phenomena of air bubbles, wrinkling and the like are not easy to occur. At this time, the UV anti-adhesive tape 200 is more firmly attached to the surface of the printed circuit board 100, and the subsequent process can be performed.

In one embodiment, step S140 specifically includes: the printed circuit board 100 is passed through a UV machine or a plasma machine to irradiate UV light to the printed circuit board 100 or perform plasma treatment.

The parameters of the plasma machine are as follows: a step of treatment, wherein the temperature rise time is 55-65min, the power is 6.5-7.5 KW, the temperature is 75-85 ℃, and the pressure is 200-300 mTorr; two-stage treatment, the holding time is 12-15min, the power is 4.5-5.5 KW, the temperature is 80-90 ℃, and the pressure is 200-300 mTorr; three-stage treatment, wherein the holding time is 1-2min, the power is 5.5-6.5 KW, the temperature is 85-95 ℃, and the pressure is 200-300 mTorr. Optionally, the temperature of the first-stage treatment is 80 ℃, the temperature of the second-stage treatment is 85 ℃, and the temperature of the third-stage treatment is 90 ℃.

If a UV machine is used, the plate passing energy of the UV machine is greater than or equal to 300 mJ.

Through adopting above-mentioned technical scheme, can reduce the peel strength of UV visbreaking sticky tape 200, be convenient for tear UV visbreaking sticky tape 200, and avoid having the cull.

It is understood that the printed circuit board 100 may be passed through the UV machine first and then the printed circuit board 100 may be passed through the plasma machine to ensure no adhesive residue.

The surface treatment method of the printed circuit board 100 is described below with an embodiment.

First, a printed circuit board 100 is provided, which specifically includes: cutting, inner layer circuit manufacturing, pressing, drilling, copper plate electroplating, outer layer circuit manufacturing and resistance welding.

The cutting refers to cutting the copper-clad plate, the PP (prepreg) or the pressing auxiliary material into a working plate with a specified size.

The inner layer circuit fabrication includes fabricating an inner layer circuit pattern of the multilayer printed circuit board 100.

In the laminating step, the copper foil, the PP, and the inner core board are laid out according to a preset stacking configuration, and laminated under a high temperature and high pressure condition to form the multilayer printed circuit board 100.

And the drilling is to use an X-ray drilling target machine to machine the positioning holes at the edges of the plate, and to use a mechanical drilling machine and/or a laser drilling machine to drill holes (including metallized and/or non-metallized holes) preset in the unit and other types of tool holes at the edges of the plate.

The copper deposition and plate electric plating is to deposit copper in the holes to be metallized and electroplate a copper layer with a specified thickness.

The outer layer circuit manufacturing refers to manufacturing a circuit pattern on the outermost layer of the multilayer printed circuit board 100.

Solder mask is formed by silk-screen printing or spraying solder mask ink on the exposed copper surface of the outermost layer of the printed circuit board 100 to cover the copper surface which is not required to be exposed. The exposed copper surface (pad or hole wall) needs to be subjected to surface treatment in a post process, and a protective layer of tin, silver, gold, OSP and the like is formed on the copper surface in a chemical deposition or electrochemical plating mode to prevent the copper surface from being oxidized before formal welding of the PCB.

Then, a UV anti-adhesive tape 200 is attached on the printed circuit board 100, including: cutting, punching, windowing and rubberizing.

The cutting means cutting the roll material into the UV anti-adhesive tape 200 matching the size of the printed circuit board 100 so as to apply the anti-adhesive on the rear surface.

The punching refers to making a first positioning hole 220 on the UV anti-adhesive tape 200 using a PP punch, a mechanical drill, or a laser drill. In the embodiment, a PP punching machine is used for processing, and the UV viscosity-reducing adhesive is punched after the punching position is determined. Note that the difference between the upper surface and the lower surface, the first positioning hole 220 is punched twice for the UV anti-adhesive of different surface. The position and the size of the first positioning hole 220 correspond to those of the second positioning hole on the printed circuit board 100, and the punching precision is controlled to be +/-0.05 mm.

The windowing refers to windowing the UV anti-adhesive tape 200 after the punching is finished to form a windowing portion 210, and the milling and routing forming, the punching and forming and the laser cutting forming can be adopted, in this embodiment, the milling and routing forming is adopted, and the tolerance of the routing size is controlled to be less than or equal to 0.1 mm. Attention is paid to the difference of the outer layer circuit patterns of the upper surface and the lower surface of the printed circuit board 100, and UV anti-adhesive glue of different surfaces is milled twice. When the board is milled, a base plate needs to be arranged below the UV anti-sticking adhesive tape 200, and a cover plate is arranged on the base plate, so that milling is facilitated, and meanwhile, a glue film can be supported and protected. The backing plate and the cover plate can be made of bakelite plates, PP plates, phenolic resin plates and the like.

When the UV anti-adhesive tape 200 is attached, a general positioning jig may be used for attachment. Firstly, adjusting the position of the positioning pin 330 to be suitable for the dimension of the printed circuit board 100 to be filmed and the position of the second positioning hole; positioning the printed circuit board 100 on the positioning pins 330; tearing off the release film of the UV anti-adhesive tape 200 for the upper surface, and then attaching the UV anti-adhesive tape 200 to the printed circuit board 100; adjusting the position of the positioning pin 330 to be suitable for the positioning specification of the lower surface of the printed circuit board 100, positioning the printed circuit board 100 on the positioning pin 330, tearing off the release film of the UV anti-adhesive tape 200 for attaching to the lower surface of the printed circuit board 100, and then attaching the UV anti-adhesive tape 200 to the printed circuit board 100. Wherein the film sticking sequence of the upper surface and the lower surface is not sequential, and the operation can be carried out randomly. Then, the printed circuit board 100 having both sides to which the UV detackifying tape 200 is attached passes through a film sticking machine once. Because the peeling strength of the UV adhesive tape 200 is within the range of 10-15gf/25mm at normal temperature, namely the UV adhesive tape 200 can be firmly attached to the surface of the printed circuit board 100 at normal temperature, the situation that the UV adhesive tape 200 is positioned and deviated when passing through a film sticking machine does not need to be worried. The temperature of the upper and lower rollers of the film sticking machine is 110-130 ℃, the pressure of the upper and lower rollers is 3.5-4.5kg, and the speed of passing the film is 2-2.5 m/min. After passing through the film sticking machine, the whole printed circuit board 100 is not allowed to have the undesirable phenomena of air bubbles, wrinkles and the like. At this time, the UV anti-adhesive tape 200 is more firmly attached to the surface of the printed circuit board 100, and the subsequent process can be performed.

Then, carrying out the selection: on the copper side not protected by the UV detackifying tape 200, a nickel gold protective layer of the specified thickness was deposited.

Then, the printed circuit board 100 is passed through a plasma machine or a UV machine, which may be set as described in the previous embodiment, to weaken the adhesiveness of the UV anti-adhesive tape 200. After the UV machine is started, the machine needs to be warmed up for 15-20 min so as to ensure that the energy is sufficient when the UV machine passes through. The energy needs to be tested before passing through the UV machine, and the plate passing energy is required to be more than or equal to 330 mJ. Since the UV visbreaker has failed at this time and the peel strength is < 5gf/25mm, the PET film 230 and the UV visbreaker layer 240 attached to the PET film can be directly removed.

The exposed copper side (i.e., the non-selected copper side) after the removal of the UV detackifying tape 200 is subjected to another surface treatment to protect the copper layer from oxidation, in this embodiment, the OSP treatment is selected. Then, FQC and packaging are performed.

A second aspect of the present invention provides a printed circuit board treated by the surface treatment method of the printed circuit board as in the first aspect.

The printed circuit board can be selected under the protection of the UV adhesive tape 200, then the UV adhesive tape 200 is peeled off after UV light irradiation or plasma treatment, and then other surface treatment is carried out, so that the manufacturing cost is low, the surface treatment efficiency is high, and the printed circuit board has good quality.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.