阅读说明：本技术 一种高厚径比hdi板的加工方法 (Method for processing HDI plate with high thickness-diameter ratio ) 是由 梁丽娟 高原 雷雨辰 于 2020-06-19 设计创作，主要内容包括：本发明公开了一种高厚径比HDI板的加工方法,属于印制板制造技术领域。本发明的高厚径比HDI板的加工方法,将图形镀分为两次,一次图形镀时不镀面只镀孔,二次图形镀时常规镀,从而保证面铜就和普通板的面铜厚度相当,降低了高厚径比HDI的面镀难度；而现有工艺得到的面铜的厚度为底铜、整板镀铜与后期的图形镀铜厚度,高厚径比HDI由于板子厚、孔小、线宽/线间距小的特点,图形电镀时通常面铜已经镀得很厚导致线条粘连而孔铜厚度不能满足要求；本发明保证了孔铜和面铜的厚度满足要求,又不影响蚀刻和丝印的质量,可广泛应用于行业内高厚径比HDI板的加工。本发明解决了由于表面图形分布不均而局部镀粗的问题。(The invention discloses a method for processing an HDI board with a high thickness-diameter ratio, and belongs to the technical field of printed board manufacturing. According to the processing method of the HDI board with the high thickness-diameter ratio, the pattern plating is divided into two times, only holes are plated on the non-plated surface during the primary pattern plating, and the conventional plating is performed during the secondary pattern plating, so that the surface copper thickness is equal to that of a common board, and the surface plating difficulty of the HDI board with the high thickness-diameter ratio is reduced; the thickness of surface copper obtained by the prior art is the thickness of bottom copper, whole plate copper plating and later pattern copper plating, and the thickness of the surface copper is higher than that of HDI (high aspect ratio) because of the characteristics of thick plate, small hole and small line width/line spacing, the surface copper is plated to be very thick usually during pattern electroplating, so that lines are adhered, and the thickness of the hole copper cannot meet the requirement; the method ensures that the thickness of the hole copper and the surface copper meets the requirements, does not influence the quality of etching and silk-screen printing, and can be widely applied to the processing of HDI plates with high thickness-diameter ratio in the industry. The invention solves the problem of local rough plating caused by uneven distribution of surface patterns.)

1. The method for processing the HDI plate with the high thickness-to-diameter ratio is characterized by comprising the following steps of:

1) carrying out first pattern transfer on a board obtained by drilling, copper deposition and whole board electroplating, and then carrying out first pattern electroplating, wherein the electroplating area is a bonding pad and a hole;

electroplating by using a copper plating solution until the thickness of the hole copper is 20-25 mu m, and then carrying out post-treatment of stripping and polishing;

2) carrying out second pattern transfer on the board, and then carrying out second pattern electroplating, wherein the electroplating area is a line and a hole;

and electroplating by using a copper plating solution until the thickness of the hole copper is 35-40 mu m, and then carrying out post-treatment to obtain the HDI board with the high thickness-diameter ratio.

2. The method for processing the HDI board with the high thickness-to-diameter ratio as claimed in claim 1, wherein the first pattern plating in the step 1) adopts a spot plating method, and the current density is 1.5A/dm²。

3. The method for processing the HDI board with the high thickness-to-diameter ratio as claimed in claim 1, wherein the step 1) further comprises the following operations before the first pattern plating:

cleaning, micro-etching and acid-washing treatment.

4. The method for processing the HDI board with the high thickness-to-diameter ratio as claimed in claim 3, wherein the micro-etching treatment is as follows:

placing the plate in Na₂S₂O₈Treating in water solution for 0.5-1 min.

5. The method for processing an HDI board with high thickness-to-diameter ratio as claimed in claim 1, wherein the current density of the second pattern plating in the step 2) is 1.5A/dm²The electroplating time is 40-60 min.

6. The method for processing the HDI board with the high thickness-to-diameter ratio as claimed in claim 1, wherein the second pattern plating in the step 2) further comprises the following operations before:

cleaning, micro-etching and acid-washing treatment.

7. The method for processing the HDI board with the high thickness-to-diameter ratio as claimed in claim 1, wherein the post-treatment in the step 2) comprises the following operations:

acid leaching treatment and tin electroplating.

Technical Field

The invention belongs to the technical field of printed board manufacturing, and particularly relates to a method for processing an HDI board with a high thickness-diameter ratio.

Background

The processing of the HDI printed board with high thickness-diameter ratio is a difficult problem in the industry, and the conventional processing technology is adopted, such as: .. laminated drilling → copper deposition → whole board electroplating → pattern transfer → pattern electroplating → alkaline corrosion …, the problem that holes and lines cannot be compatible in the electroplating process is generated, namely, the surface copper is thick, the hole copper thickness still cannot meet the standard requirement, the surface copper is too thick, the etching and silk-screen printing are difficult, and in addition, if the wiring distribution of the outer layer is not uniform, the local line plating is also coarse.

Disclosure of Invention

The invention aims to overcome the defect that surface copper and hole copper cannot be considered in the existing HDI printed board processing technology, and provides a processing method of an HDI board with a high thickness-diameter ratio.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

a method for processing an HDI plate with a high thickness-to-diameter ratio comprises the following steps:

1) carrying out first pattern transfer on a board obtained by drilling, copper deposition and whole board electroplating, and then carrying out first pattern electroplating, wherein the electroplating area is a bonding pad and a hole;

electroplating by using a copper plating solution until the thickness of the hole copper is 20-25 mu m, and then carrying out post-treatment of stripping and polishing;

2) carrying out second pattern transfer on the board, and then carrying out second pattern electroplating, wherein the electroplating area is a line and a hole;

and electroplating by using a copper plating solution until the thickness of the hole copper is 35-40 mu m, and then carrying out post-treatment to obtain the HDI board with the high thickness-diameter ratio.

Further, the first pattern electroplating in the step 1) adopts a point plating method, and the current density is 1.5A/dm²。

Further, the first pattern electroplating in the step 1) further comprises the following operations:

cleaning, micro-etching and acid-washing treatment.

Further, the microetching treatment comprises the following steps:

placing the plate in Na₂S₂O₈Aqueous solutionTreating for 0.5-1 min.

Further, the current density of the second pattern plating in the step 2) is 1.5A/dm²The electroplating time is 40-60 min.

Further, before the second pattern plating in step 2), the following operations are also included:

cleaning, micro-etching and acid-washing treatment.

Further, the post-processing in step 2) comprises the following operations:

acid leaching treatment and tin electroplating.

Compared with the prior art, the invention has the following beneficial effects:

according to the processing method of the HDI board with the high thickness-diameter ratio, the pattern plating is divided into two times, only holes are plated on the non-plated surface during the primary pattern plating, and the conventional plating is performed during the secondary pattern plating, so that the surface copper thickness is equal to that of a common board, and the surface plating difficulty of the HDI board with the high thickness-diameter ratio is reduced; the thickness of surface copper obtained by the prior art is the thickness of bottom copper, whole plate copper plating and later pattern copper plating, and the thickness of the surface copper is higher than that of HDI (high aspect ratio) because of the characteristics of thick plate, small hole and small line width/line spacing, the surface copper is plated to be very thick usually during pattern electroplating, so that lines are adhered, and the thickness of the hole copper cannot meet the requirement; the method ensures that the thickness of the hole copper and the surface copper meets the requirements, does not influence the quality of etching and silk-screen printing, can be widely applied to the processing of HDI plates with high thickness-diameter ratio in the industry, and has higher economic benefit. The invention solves the problem of local rough plating caused by uneven distribution of surface patterns.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not a whole embodiment. 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.

It is noted that the terms first, second and the like in the description and in the claims of the present invention are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention discloses a method for processing an HDI plate with a high thickness-to-diameter ratio, which comprises the following steps:

1. engineering document production

When designing engineering documents, manufacturing plated hole negative files named as xxxxxxdk.gtl and xxxxdk.gbl on the basis of original documents;

the diameter of the bonding pad of the plating negative plate is 0.15-0.2 mm larger than that of the conducting hole.

And reserving 10-15 mm of the edge of the electroplating edge clamp, and calculating the area of a plated hole (including the area of the hole, the area of a bonding pad and the area of the electroplating edge).

And manufacturing a positioning hole welding disc corresponding to the drilling file on the plating hole bottom sheet.

Other conventional engineering document production methods are unchanged.

2.… … laminating → drilling → copper deposition → whole plate electroplating

Processing according to the conventional processing flow and manufacturing method of the printed circuit board until the whole board is electroplated.

3. First pattern making, making a plating hole pattern

The pattern transfer medium is polyester dry film and is a photosensitive material.

3.1 flow scheme

Surface treatment (brushing/sandblasting) → laminating → negative punching → alignment → exposure → development → turning down

3.2 function and parameters:

3.2.1 film pasting: and adhering the polyester dry film to the board by using a hot pressing roller according to the size of the board with the holes to be plated after the whole board is electroplated.

TABLE 1 film parameters

Item	Rubber roll temperature/. degree.C	pressure/MPa	Speed/(m/min)
				Range of	100～120	0.4～0.6	0.8～1.5

3.2.2 para: the plated negative films xxxxdk.gtl and xxxxdk.gbl, which correspond to the film-coated board registration holes, were used, and were positive negative films.

3.2.3 Exposure: by utilizing the photosensitivity of the polyester dry film, the position with the film on the negative film is protected, the position without the film is exposed, and the exposure parameters are shown in the table 2.

TABLE 2 Exposure parameter Table

3.2.3 development: the pattern protected by the medicine film is developed to expose copper, namely a part needing electroplating, only a bonding pad and a hole are exposed in the process, the distance between a single edge of the hole and the polyester dry film is 0.05-0.10 mm, and the developing parameters are shown in a table 3:

TABLE 3 development parameters

4. Electroplating hole (Pattern electroplating 1)

Plating holes by adopting a point plating method, wherein the current density is 1.5A/dm according to the plating hole area given by an engineering document²And the electroplating time is 60min, and the thickness of the electroplated hole copper is 20-25 um.

4.1 the procedure is as follows:

upper plate → cleaning → microetching → acid cleaning → electrocoppering → lower plate → stripping → upper plate

Compared with the conventional electroplating process, the process has less pickling and electroplating before electroplating tin, and no etching is needed after the process, so that no tin plating resist is needed to be generated.

4.2 function

Cleaning: the cleaning agent is an acidic cleaning agent and is used for removing plate surface fingerprints and oil stains;

micro-etching: the surface of the conductive pattern has certain micro roughness, which is beneficial to improving the bonding force of the plating layer and the bottom layer;

acid pickling before copper plating: removing the oxidation of the plate surface and protecting the copper plating solution;

copper electroplating: a layer of compact metal copper is deposited on the surface and in the hole of the conductive pattern, and the thickness of the plating layer meets the process requirement;

stripping and hanging: removing residual copper on the pinch points by using a dilute nitric acid solution to prevent the bath solution from being polluted;

washing with water: the board surface is cleaned to prevent the cross contamination of the bath solution.

4.3 process parameters, wherein the wetting agents in the table are the components: from 90.0% to 99.6% water and from 1.0% to 5.0% alkylene oxide polymer; the brightener comprises the following components: 90.0% to 99.6% water and 1.0% to 5.0% alkylene oxide polymer.

TABLE 4 copper electroplating process control parameter table

5. Film fading film

5.1 scheme:

transfer → bulking → stripping → roller motor → pressure washing 1 → high pressure washing → pressure washing 2 → pressure washing 3 → cold air drying → hot air drying heating → discharge cooling → self-checking

5.2 formula of solution in cylinder:

TABLE 5 open vat solution formulation

5.3, film removing technological parameters:

TABLE 6 Process parameters

6. Polishing

After stripping, the burr at the orifice is removed in a manual grinder or a belt grinder until the surface is as flat as the surface.

7. Hole line pattern making (pattern making 2)

The process is the same as that of the pattern manufacturing 1, all patterns for pcb conduction are manufactured, the electroplating area is lines and a conduction hole, after a brush board and a film are manufactured according to the pattern manufacturing 1, a plating hole bottom plate xxxxxx.gtl and xxxxxx.gbl are used for aligning according to corresponding positioning holes, and after exposure and development, the distance between a hole single side and a dry film is not less than 0.13 mm.

8. Hole plating line (graph electroplating 2)

8.1 scheme: compared with the pattern plating 1, the acid dipping and the tin plating are added before the tin plating, and the tin plating is used for protecting the copper of the effective pattern from being corroded during the alkaline etching.

Cleaning → microetching → acid cleaning → copper electroplating → acid pickling → tin electroplating → lower plate → stripping → upper plate

The current density of the pattern electroplating line is 1.5A/dm²The electroplating time is 40-60 min, and the thickness of the copper in the holes after electroplating is 35-40 um.

8.2 function

Acid washing before tinning: removing the oxidation of the plate surface and protecting the tin plating solution;

electroplating tin: plating a copper plating resist layer on the conductive pattern surface after the copper electroplating;

8.3 Process parameters

TABLE 7 control parameter table for tin electroplating process

Other plating with the same pattern 1

9. Alkaline etching

Starting from alkaline etching, the method enters the conventional processing flow of the printed board and is processed by using the conventional process.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.