阅读说明：本技术 一种超薄5g类覆铜板的覆膜方法及该覆铜板的制备方法 (Film covering method of ultrathin 5G copper-clad plate and preparation method of copper-clad plate ) 是由 鲜盛鸣 王卫华 于 2019-09-09 设计创作，主要内容包括：本发明提供了一种超薄5G类覆铜板的覆膜方法及该覆铜板的制备方法,包括以下步骤：1)激光开窗：利用激光对覆盖膜进行开窗处理,形成镂空板；2)覆盖膜对位：将覆盖膜开窗处理后形成的图案与超薄5G类覆铜板表面的线路图形对准；3)定位热压：将对位后的所述覆盖膜与超薄5G类覆铜板进行粘接,热压后完成固定。所述方法通过对厚度仅为0.2mm的基板表面进行热压覆盖膜以代替传统的阻焊工艺,能够改善由于传统阻焊加工过程中存在的厚度不均、表面覆盖效果差、阻焊面受环境影响等产生的外观垃圾,阻焊薄板固化不方便、阻焊加工周期时间长等问题。(the invention provides a film coating method of an ultrathin 5G copper-clad plate and a preparation method of the copper-clad plate, which comprise the following steps: 1) laser windowing: windowing the covering film by using laser to form a hollow-out plate; 2) aligning the covering film: aligning a pattern formed after windowing treatment of the cover film with a circuit pattern on the surface of the ultrathin 5G class copper-clad plate; 3) positioning and hot pressing: and (3) bonding the aligned covering film with the ultrathin 5G copper-clad plate, and fixing after hot pressing. According to the method, the hot-pressing covering film is carried out on the surface of the substrate with the thickness of only 0.2mm to replace the traditional solder mask process, so that the problems that the solder mask sheet is inconvenient to cure, the solder mask processing period is long and the like due to appearance garbage generated by uneven thickness, poor surface covering effect, influence of the environment on the solder mask surface and the like in the traditional solder mask processing process can be solved.)

1. a film coating method of an ultrathin 5G copper-clad plate is characterized by comprising the following steps:

1) Laser windowing: windowing the covering film by using laser to form a hollow-out plate;

2) aligning the covering film: aligning a pattern formed after windowing treatment of the cover film with a circuit pattern on the surface of the ultrathin 5G class copper-clad plate;

3) Positioning and hot pressing: and (3) bonding the aligned covering film with the ultrathin 5G copper-clad plate, and fixing after hot pressing.

2. the method of claim 1 wherein in step 2) the cover film temperature at the time of alignment is 400 ± 20 ℃.

3. The method according to claim 2, wherein the cover film and the ultra-thin 5G copper clad laminate are spot-welded using a branding plate after the alignment, and then hot-pressed.

4. The method according to claim 1, wherein in the step 3), the hot pressing temperature is 180-220 ℃ and the time is 200-300 s.

5. A preparation method of an ultrathin 5G copper-clad plate is characterized by comprising the following steps:

(1) Pretreatment: cutting a substrate according to the actual size requirement, and mechanically drilling holes, wherein the substrate is made of organic resin;

(2) copper deposition: filling holes in the substrate and electroplating to increase the thickness of the hole copper in the through holes to 5-8 microns;

(3) Pattern transfer: pasting an anti-electroplating layer dry film on the surface of the substrate, and then exposing and imaging;

(4) And (3) developing: developing the product which is exposed and imaged;

(5) Pattern electroplating: carrying out copper plating and tin plating treatment on the developed product;

(6) Etching: etching the surface of the product by using etching liquid to obtain a finished circuit pattern;

(7) pretreatment: performing pretreatment by using a grinding brush or a microetching solution to remove an oxide layer on the board surface;

(8) Film covering: laminating according to the method of any one of claims 1 to 4;

(9) And printing, curing, forming and surface treating the surface of the product.

6. the method of claim 5, wherein in step (1), the substrate is an ultra-thin printed circuit board with a thickness of 0.25mm or less.

7. The method of claim 5, wherein in step (3), the photo-plotting film is used for film alignment, and then exposure imaging is performed by using an exposure machine, or automatic exposure imaging is performed by using LDI.

8. the method according to claim 5, wherein in the step (4), a sodium carbonate or potassium carbonate solution with a mass concentration of 1-1.2% is used for development, the development time is 55-65 s, and the temperature is 30-33 ℃.

9. The method according to claim 5, wherein in the step (5), the copper plating is carried out in a copper plating solution, and the copper plating thickness is 15-20 microns; the current density of the tinning is 12ASF, and the tinning thickness is 3-5 microns.

10. the method of claim 5, wherein in the step (9), the surface treatment is a conventional PCB tin deposition process, and the tin deposition thickness is 0.8-1.2 μm.

Technical Field

The invention relates to the technical field of printed circuits, in particular to a film coating method of an ultrathin 5G copper-clad plate and a preparation method of the copper-clad plate.

background

As the printed electronics gradually shift from 4G to 5G, the demand for ultra-thin high-speed materials is also increasing. For non-FPC manufacturers, rigid ultra-thin printed boards present a significant challenge. According to the special requirements of 5G antenna products of terminal customers, a high-speed low-dielectric-constant copper-clad plate with the thickness of less than or equal to 0.25mm and the common thickness of 0.2mm is required to be used. The thickness exceeds the process requirement that the thickness of the copper-clad plate of the conventional equipment is more than or equal to 0.30mm, and the problem of difficult processing exists in the traditional solder mask manufacturing process. And the copper-clad plate prepared by the traditional screen printing mode usually resists solder ink with uneven thickness, and has certain quality influence on signal transmission, impedance and tin deposition layering.

Therefore, a manufacturing method suitable for the copper-clad plate with the thickness less than or equal to 0.25mm needs to be provided, so that the problem of difficult waste generated in the contact process of environment, screen printing plate, printing ink and personnel in the traditional solder resisting mode can be fundamentally solved while the thickness required by a client is achieved.

in view of this, the invention is particularly proposed.

Disclosure of Invention

The first purpose of the invention is to provide a film coating method of an ultrathin 5G copper-clad plate.

The second purpose of the invention is to provide a preparation method of the copper-clad plate.

In order to achieve the purpose, the technical scheme of the invention is as follows:

The invention relates to a film coating method of an ultrathin 5G copper-clad plate, which comprises the following steps:

1) Laser windowing: windowing the covering film by using laser to form a hollow-out plate;

2) aligning the covering film: aligning a pattern formed after windowing treatment of the cover film with a circuit pattern on the surface of the ultrathin 5G class copper-clad plate;

3) Positioning and hot pressing: and (3) bonding the aligned covering film with the ultrathin 5G copper-clad plate, and fixing after hot pressing.

preferably, in the step 2), the temperature of the covering film is 400 +/-20 ℃ during alignment, and after alignment, a branding plate is used for spot welding the covering film and the ultrathin 5G copper-clad plate, and then hot pressing is carried out.

Preferably, in the step 3), the hot pressing temperature is 180-220 ℃ and the time is 200-300 s.

the invention also relates to a preparation method of the ultrathin 5G copper-clad plate, which comprises the following steps:

(1) Pretreatment: cutting a substrate according to the actual size requirement, and mechanically drilling holes, wherein the substrate is made of organic resin;

Preferably, the substrate is an ultrathin printed circuit board, and the thickness of the ultrathin printed circuit board is less than or equal to 0.25 mm.

(2) copper deposition: filling holes in the substrate and electroplating to increase the thickness of the hole copper in the through holes to 5-8 microns;

(3) pattern transfer: pasting an anti-electroplating layer dry film on the surface of the substrate, performing film alignment by using a photo-drawing negative film, and then performing exposure imaging by using an exposure machine or performing automatic exposure imaging by using LDI (laser direct immersion imaging);

(4) And (3) developing: developing the product which is exposed and imaged;

preferably, the developing uses sodium carbonate or potassium carbonate solution with the mass concentration of 1-1.2%, the developing time is 55-65 s, and the temperature is 30-33 ℃.

(5) Pattern electroplating: carrying out copper plating and tin plating treatment on the developed product;

Preferably, the copper plating is carried out in a copper plating solution, and the copper plating thickness is 15-20 microns; the current density of the tinning is 12ASF, and the tinning thickness is 3-5 microns.

(6) Etching: etching the surface of the product by using etching liquid to obtain a finished circuit pattern;

(7) Pretreatment: performing pretreatment by using a grinding brush or a microetching solution to remove an oxide layer on the board surface;

(8) Film covering: coating the film according to the method described above;

(9) and printing, curing, forming and surface treating the surface of the product.

Preferably, in the step (9), the surface treatment is a conventional PCB tin deposition process, and the tin deposition thickness is 0.8-1.2 μm.

the invention has the beneficial effects that:

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

The embodiment of the invention relates to a film coating method of an ultrathin 5G copper-clad plate, which comprises the following steps:

1) Laser windowing: and carrying out windowing treatment on the covering film by using laser to form the hollow-out plate.

2) Aligning the covering film: and aligning a pattern formed after windowing treatment of the cover film with a circuit pattern on the surface of the ultrathin 5G copper-clad plate, and compounding the reverse side of the cover film with the front side of the ultrathin 5G copper-clad plate.

In one embodiment of the present invention, the coverlay film comprises a coverlay film body, a solid resin adhesive and a release film sequentially compounded together. In actual operation, the release film on the surface layer is removed, so that the solid resin adhesive is attached to the surface of the ultrathin 5G copper-clad plate, and then the cover film is hot-pressed to realize positioning. The temperature of the covering film is set to be 400 +/-20 ℃ during alignment, if the temperature is too low, fixation is difficult to realize, and if the temperature is too high, the body of the covering film is easy to damage. In order to prevent the cover film and the ultrathin 5G copper-clad plate from moving relatively, the cover film and the ultrathin 5G copper-clad plate are preferably subjected to spot welding by using a branding iron plate after alignment, 4-6 points can be fixedly fused at the edge and the center of the cover film, and then hot pressing is carried out.

3) Positioning and hot pressing: and (4) bonding the aligned covering film with the ultrathin 5G copper-clad plate, and fixing after hot pressing.

In one embodiment of the present invention, the hot pressing temperature is 180-220 ℃ and the time is 200-300 s. Before hot pressing, the product coated with the cover film can be well protected by using a separation film, and then the product is placed into a hot pressing furnace for hot pressing. Since the cover film already contains a solid resin glue, no glue is needed in this step. If the covering film does not contain solid resin glue, epoxy resin glue or acrylic glue can be used for bonding.

the embodiment of the invention also relates to a preparation method of the ultrathin 5G copper-clad plate, which comprises the following steps:

(1) Pretreatment: and cutting the substrate according to the actual size requirement, and mechanically drilling holes, wherein the substrate is made of organic resin.

In one embodiment of the present invention, the substrate is an ultra-thin printed circuit board, which is also called a PCB hard board or a printed circuit board. The invention mainly aims at the improvement of an ultrathin printed circuit board with the thickness of less than or equal to 0.25mm and the thickness of 0.2mm, which is used for 5G antenna products.

(2) Copper deposition: and (3) filling holes on the substrate and electroplating to increase the thickness of the copper in the through holes to 5-8 microns. The copper deposition is performed by depositing a thin layer of copper chemically in the via walls, which can be performed in a dilute sulfuric acid solution containing copper ions.

(3) Pattern transfer: and pasting an anti-electroplating layer dry film on the surface of the substrate, carrying out film alignment by using a photo-drawing negative film, and then carrying out exposure imaging by using an exposure machine or carrying out automatic exposure imaging by using LDI (laser direct immersion imaging). Because the LDI directly images the image on the PCB by using a laser scanning method, the image is finer, a negative film procedure in the exposure process can be omitted, the time and the cost for loading and unloading the negative film are saved, the deviation caused by the expansion and shrinkage of the negative film is reduced, the production yield of the PCB is improved, and the LDI imaging is more inclined at present.

(4) And (3) developing: and developing the product which is exposed and imaged.

In one embodiment of the invention, sodium carbonate or potassium carbonate solution with the mass concentration of 1-1.2% is used for development, the development time is 55-65 s, and the temperature is 30-33 ℃. The product which has been exposed to light and imaged may be left to stand for 15 minutes and then developed by a developing machine.

(5) Pattern electroplating: and carrying out copper plating and tin plating treatment on the developed product.

The pattern electroplating is to electroplate a copper layer and a tin layer which reach the required thickness on the exposed copper sheet or the hole wall of the circuit pattern. In one embodiment of the invention, copper plating is carried out in a copper plating solution, and the copper plating thickness is 15-20 microns; the current density of the tinning is 12ASF, and the tinning thickness is 3-5 microns.

(6) etching: and etching the surface of the product by using an etching solution to obtain a finished circuit pattern, wherein the purpose is to remove the copper layer of the non-circuit part by using chemical reaction.

(7) pretreatment: and (4) carrying out pretreatment by using a grinding brush or a microetching solution to remove an oxide layer on the board surface.

(8) film covering: and (3) laminating according to the method, wherein the steps of laser windowing, cover film alignment and positioning hot pressing are included, and the copper-clad plate after laminating is obtained.

In the prior art, a solder resist mode is adopted to realize a film coating effect. The Solder resist ink is a Solder Mask in English, has various colors of red, blue, green, purple, white, black and the like, and is also called green oil in the industry because the green color is the most commonly used. The solder resist ink is viscous before use and is an acrylic oligomer. Through the operation flows of printing, pre-baking, alignment, exposure, development, post-curing and the like, the positions needing to be welded or assembled by a terminal customer are all exposed, the positions of the base material and the copper foil which do not need to be welded or assembled are all covered by the solder resist ink, and the solder resist layer has excellent acid and alkali resistance, solvent resistance, high temperature resistance and the like. However, as described in the background art, since the solder resist ink has uneven thickness, there is a certain quality influence on signal transmission, impedance and tin deposition delamination, and the rejection rate of the finished product is high.

The method provided by the invention can control the solder mask thickness of the ultra-thin high-speed material silk screen in the hot printing process to be consistent, and is not easy to generate the problems of garbage, scratch, board breakage, manual operation such as frame insertion and the like in the solder mask process, thereby greatly shortening the production period, avoiding solder mask layering and improving the product quality. The method can also reduce the application of water, electricity and chemicals in the solder mask developing process.

(9) And printing, curing, forming and surface treating the surface of the product.

in one embodiment of the invention, the surface treatment is a conventional PCB tin deposition process, and the tin deposition thickness is 0.8-1.2 μm.

in one embodiment of the invention, a 120T screen is used for text printing; the curing temperature is 150 ℃ and the curing time is 30 minutes; forming by normal CNC according to the shape and size; in the surface treatment process, the problems that solder resist ink cannot resist the attack of tin deposition liquid medicine and oil throwing frequently exists in the traditional process can be solved, and the repeated reworking tin deposition can be carried out.