KR102161257B1 - Method of surface treatment for copper materials and their surface treatment liquids - Google Patents

Abstract

The present invention is a method for forming a roughness by etching a metal surface to improve adhesion between a metal surface selected from copper and its alloy material and a resin layer, wherein the roughness formation is (a) copper chloride, (b) organic acid, (c) Inorganic acid, (d) alkali metal halide, (e) any one or more components selected from benzotriazole and alkali metal formate, and (f) a copper-based metal comprising an etching step formed by treatment with an etching solution containing a residual amount of water It is to provide a method of forming surface roughness.

Description

[Method of surface treatment for copper materials and their surface treatment liquids]

The present invention relates to a method for chemical surface treatment of a surface of a copper layer and a composition thereof for enhancing adhesion with a resin layer in a printed circuit board manufacturing process.

In the process of manufacturing a printed circuit board, in order to increase adhesion to the dry film for forming a circuit or the solder resist of the outer layer, it is mainly processed through an etching process of sulfuric acid and fruit trees. Such a method of surface treatment using sulfuric acid and fruit water-based chemicals has a low surface roughness, so it is impossible to produce a highly reliable substrate by maximizing adhesion to the target material.

Sulfuric acid and fruit water type etching chemicals manage stable etching rate by adding hydrogen peroxide stabilizer, and supplement and discharge chemicals for continuous production while maintaining the amount of copper as a by-product within a certain range.

However, since sulfuric acid and hydrogen peroxide-based etching does not have a pretreatment process, contaminants on the substrate cannot be completely removed, causing stains on the substrate depending on the contamination state of the substrate. In addition, after the treatment, the surface becomes a pure Cu state, and oxidation proceeds easily to a CuO or Cu ₂ O state. Therefore, the independence of the etching process is low because the etching must be performed continuously with the next process.

Conventional sulfuric acid and hydrogen peroxide-based etching agents have a roughness of about 0.2 to 0.3 μm based on the Ra value after treatment. In addition, it is difficult to maximize the adhesion with the resin layer by the movement of copper ions by maintaining the pure copper surface state after treatment. On the other hand, the purpose of the present invention is to increase the physical bonding strength by raising the roughness of the surface to Ra 0.4um or more, and to prevent the decrease in adhesion due to the movement of copper ions through the formation of an organic layer on the surface, thereby maximizing adhesion with the resin. have.

Circuit boards are gradually thinner and smaller, and the resin layer has a low thermal expansion/contraction expansion ratio and improved physical properties to meet a low dielectric constant, resulting in poor adhesion to the copper layer and thermal shock durability. In order to compensate for this, it is required to improve the roughness and surface treatment of the copper layer.

In addition, there are many joint parts of copper materials and resins in various electronic products, and when these resins are molded onto metal materials in a state where heat is applied, the entire part needs to be exposed to high temperatures of 100-400°C. Therefore, if the adhesion between the copper material and the resin is poor, peeling occurs at the interface between the copper material and the resin, and the copper material swells, thereby impairing the internal corrosion resistance, or in some cases, cracks in the resin. It can lead to the result that the wiring pattern is destroyed.

In general, in order to improve the adhesion between a metallic material and a resin, a technique of mechanically roughening the surface of a metallic substrate by blasting or the like to form an anchor has been used for a long time.

Japanese Patent Publication No. 2000-183235

An object of the present invention is to solve the problems cited in the conventional sulfuric acid and hydrogen peroxide-based etching solution composition, and to demonstrate a higher required adhesion, a metal material of copper and a dry film or an insulating resin layer or an outer layer of solder resist and The purpose is to provide a composition for each process and a method of improving the bonding strength of.

Conventionally, there is an advantage of using the 1st or 2nd step of the etching process, but there is a problem in that it is easily oxidized after treatment and lack of ability to remove organic matter substrate contamination. For this reason, in the present invention, it is intended to improve the quality of the printed circuit board by providing a more complete surface treatment process.

In particular, the purpose is to increase the adhesion required for products with high specifications by increasing the surface area through roughness formation of the copper surface after the etching process.

The present invention has excellent adhesion to resin, particularly at high temperatures, and does not use substances that cause environmental pollution such as hexavalent chromium. It is an object of the present invention to provide a surface treatment method, a copper material, and a lamination member.

The method for forming roughness on a copper-based metal surface according to the present invention is a method for forming roughness by etching a metal surface to improve adhesion between a metal surface selected from copper and its alloy material and a resin layer, wherein the roughness formation is (a) chlorinated Copper, (b) organic acid, (c) inorganic acid, (d) alkali metal halide, (e) any one or more components selected from benzotriazole and alkali metal formate, and (f) the remaining amount of water. It includes an etching step formed by processing.

A pre-etching step may be further included before the etching step according to an exemplary embodiment of the present invention, and the pre-etching step may be in contact with a pre-etching solution including an organic peroxide, an inorganic acid, and a residual amount of water.

The method according to an exemplary embodiment of the present invention further includes a post-etching step after the etching step, and the post-etching step may be formed by contacting a post-treatment etching solution containing an alkali metal salt.

The method according to an embodiment of the present invention may further include a post-etching step after the etching step, and the post-etching step may be formed by contacting a post-treatment etching solution containing a chlorine-based salt.

The pre-etching solution according to an embodiment of the present invention may further include any one or two or more compounds selected from hydrochloric acid, polyethyleneimine, and ethylenediamine.

In the method according to an example of the present invention, the post-etching treatment liquid may further include any one or two or more components selected from glycolic acid and monoalkanolamine.

The surface of the copper material treated with the etching solution and the post-measurement solution of the present invention is dense, and a surface having a dense roughness with an increased surface area is produced, so that adhesion strength is further increased when adhering to the resin layer.

Patented copper etched surface has the advantage of increasing the roughness density and the surface area very high, so that the adhesive surface is further increased when bonding with the resin layer, and the bonding strength is remarkably increased.

In addition, the etching rate is improved at the same time, the roughness is increased, the density of the roughness is also increased, and the adhesion is remarkably increased. In particular, it has an excellent effect of adhesion under high temperature.

FIG. 1 is a photograph of an etching surface of a copper plate etched with the etching composition of Example 2 according to an exemplary embodiment of the present invention observed by a scanning electron microscope.
FIG. 2 is a photograph of an etching surface of a copper plate etched with the etching composition of Comparative Example 2 made of general sulfuric acid and hydrogen peroxide according to a comparative example of the present invention, as observed with a scanning electron microscope.

Hereinafter, the etching process and etching composition for surface roughness of copper and its alloy according to the present invention will be described in more detail through examples. However, the following examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

In addition, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. The terms used in the description herein are merely for effectively describing specific embodiments, and are not intended to limit the invention.

The present invention will be described in detail as follows.

The inventors of the present invention intensively studied to achieve the above object, as a result of (a) copper chloride, (b) organic acid, (c) inorganic acid, (d) alkali metal halide, (e) benzotriazole and alkali metal formate selected from By using a surface treatment solution for copper materials with an etching composition containing any one or more components and (f) the remaining amount of water, the adhesion between the copper material and the resin is excellent, and the adhesion at high temperatures is further increased. Found and completed the present invention.

As an aspect of the present invention

(a) 0.1 to 5% by weight of copper chloride, (b) 0.1 to 3% by weight of organic acid, (c) 0.01 to 1% by weight of inorganic acid (d) 0.01 to 2% by weight of alkali metal halide, (e) benzotriazole and formic acid When the surface of copper is treated with an etching solution containing 0.001 to 0.2% by weight of any one or two or more components selected from alkali metals and (f) the remaining amount of water, the high-temperature adhesion to the resin is more excellent.

In addition, in the present invention, it is more preferable to further undergo a pre-etching step before treating copper with the etching solution because it is possible to increase the roughness due to etching of the surface.

The object for increasing the roughness by surface treatment with the treatment liquid of the present invention is not particularly limited as long as it is a copper material.

For example, pure copper or a copper alloy may be exemplified, and pure copper may include, for example, oxygen-free copper, and the copper alloy is not particularly limited as long as it contains 50% by weight or more of copper. For example, zinc Examples thereof include brass or other alloys containing one or two or more metals selected from Zn, P, Al, Fe, and Ni.

The copper material is not particularly limited in shape or structure. As for the shape, a plate, a sheet, a film, a rod shape, etc. are mentioned, for example.

In the present invention, the pre-etching step is preferably treated with a pre-etching solution containing an organic peroxide and an inorganic acid.

As an example of the composition of the pre-etching liquid of the present invention, it is preferable to use a pre-etching liquid containing 1 to 30% by weight of sulfuric acid, 0.1 to 10% by weight of hydrogen peroxide, and the balance of water.

In the present invention, if the pre-etching solution further contains 0.01 to 1% by weight of one or more compounds selected from hydrochloric acid, polyethyleneimine, and ethylenediamine, etching by pre-etching solution on the surface of copper-based metal by pre-etching solution and the main etching solution Etching by is combined to generate more excellent surface roughness, and the adhesion to resins is further increased. It is not particularly limited in the present invention, but preferably. It is better to limit the etching rate to 0.1 μm or less during pre-etching.

In the present invention, after etching the surface of the copper-based metal with the etching solution, performing additional etching with a later etching solution is preferred because the surface roughness can be maintained and the adhesion with the resin layer can be further improved.

In the present invention, the post-tempering solution for post-ching treatment is treated using a post-tempering liquid containing one or two or more chlorine-based salts selected from at least one sodium chloride and ammonium chloride salt. When the treatment is performed using the after-treatment liquid, components of the etchant present on the etching surface by the etchant and impurities generated therefrom are dissolved and removed, and thus there is an advantage in that there are no components desorbed from the copper metal etching surface.

In the present invention, when the content of the chlorine-based salt in the post-treatment solution is an aqueous solution containing 1 to 20% by weight, the effect to be achieved in the present invention can be achieved.

In addition, when the post-treatment solution further includes any one or more components selected from glycolic acid and monoalkanolamine with respect to the entire post-treatment solution, the foreign matter on the surface is completely removed rather than the advantage in adhesion or etching rate. When bonded, it has an excellent advantage that projections are not formed on the surface of the resin layer. When the above components are added in the post-treatment solution, the content is not particularly limited, but for example, adding 0.001 to 1% by weight of glycolic acid and 0.01 to 1% by weight of monoalkanolamine dissolves foreign substances on the etched surface. As the removal effect is further increased, the phenomenon that foreign matters remain on the surface can be completely removed, which is even better.

In the present invention, after treating the etching solution or the later etching solution, the rust prevention treatment is also included as an aspect of the present invention.

In the present invention, the rust prevention treatment may be a rust prevention composition containing 0.1 to 5% by weight of toyltriazole and the balance being water. In addition, the anti-rust composition may further include an alkali hydroxide and monoethanolamine. Examples of the alkali hydroxide include sodium hydroxide, potassium hydroxide, and lithium hydroxide, and the content of the alkali hydroxide is 0.01 to 2% by weight, monoethanolamine 0.01 to 2% by weight, which further enhances the rust prevention effect. It is good to be able to be able to, and to further increase the adhesiveness to the resin layer.

Next, look at the etching and processing time of the present invention.

The present invention can complete the present invention by washing with water after etching the copper surface by contacting the etching solution of the present invention.

Further, the present invention can complete the present invention by immersing in a pre-etching solution, washing with water, immersing in an etching solution, and washing with water.

Further, the present invention can complete the present invention by contacting the etching solution and washing with water, and then contacting the etching solution and washing with water.

In addition, the present invention can complete the present invention by treating with a pre-etching liquid, washing with water, treating with an etching liquid, washing with water, contacting with a post-treatment liquid, and washing with water.

In addition, the present invention can complete the present invention by treating the rust preventive solution at the last stage of the manufacturing process, washing with water, and drying.

In addition, the present invention may further include a drying step after washing with water in each step.

The conditions of use of the treatment solution of the present invention are not particularly limited. For example, in the case of the etching solution, the treatment temperature is 10 to 60°C, preferably at room temperature of 20 to 30°C, and the time is, but not limited to, 10 seconds. The surface is etched by immersion in the range of from 10 minutes to 10 minutes, preferably from 30 seconds to 3 minutes.

The pre-etching solution is preferably treated for 10 seconds to 1 minute at a temperature in the same range as the etching solution to finely etch the surface.Through this treatment, the etching rate by this etching solution is accelerated, and the depth and density of the etching. It is even better because it rises significantly. This is because the purpose is to remove contaminants.

The post-etching of the present invention also serves to clean up the surface by etching the remaining metal components without being desorbed by treating the surface for 10 seconds to 1 minute at a temperature in the same range as the etching solution, and the structure of the surface becomes more dense. It is good that there is no surface crushing when exposed to high temperature. In addition, it plays a role of removing the residuals of the etching solution. Therefore, by performing this post-ching treatment, particles that are desorbed are eliminated and the surface is arranged, so that the adhesion is further improved.

The rust prevention treatment is not particularly limited, but it is possible to prevent rust caused by oxygen in the air by treating it at 10 to 60°C for 10 seconds to 1 minute, so it has the effect of suppressing changes in the chemical properties of the surface due to storage during long-term use.

According to the present invention, the etching rate is 0.5 μm/min, the roughness is 0.21 (Ra) or more, preferably 0.4 (Ra), and the adhesion is 0.3 kgf/cm, preferably 0.5, and more preferably 0.6 kgf/cm or more. Can be obtained. The physical properties were measured and obtained by the following method.

The surface of the copper material treated with the nicking liquid and the post nicking liquid of the present invention is dense, and a surface having a dense roughness with an increased surface area is produced, so that adhesion is further increased when adhering to the resin layer.

Patented copper etched surface has the advantage of increasing the roughness density and the surface area very high, so that the adhesive surface is further increased when bonding with the resin layer, and the bonding strength is remarkably increased.

Also, the nicking rate is improved at the same time, the roughness is increased, the roughness density is also increased, and the adhesion is remarkably increased. In particular, it has an excellent effect of adhesion under high temperature.

The treatment method of the present invention includes a treatment step of bringing a copper material into contact with the treatment liquid of the present invention described above. The method of contacting the treatment liquid of the present invention is not particularly limited, and various known treatment methods such as dipping, spraying, and flow may be used, but are not limited thereto.

In addition, in the case of dipping, the presence or absence of agitation in the treatment liquid bath is not particularly limited, and in the case of flow coating, the amount of flush is not particularly limited as long as it is sufficiently wet, and the spray pressure in the spray treatment, the type of spray nozzle, etc. Is not particularly limited.

The present invention will be described in detail by showing examples below. However, the present invention is not limited to these, and the physical properties obtained in Examples and Comparative Examples were measured by the following method.

Measurement of etch rate

In the present invention, the etching rate was processed by the present invention using CCL (Copper clad laminate, EM-285), and then converted into thickness through weight change.

Measurement of adhesive strength

In addition, the measurement of the adhesive strength in the present invention is a copper foil (Copper foil, Iljin Material) of 1 ounce thickness is treated by the means of the present invention, and then laminated with a prepreg (DS-7402, hi-Tg) resin and then pressed. It was molded by thermosetting by holding at a pressure of 30 kg at 190° C. for 2 hours. After lamination molding, the copper foil layer was peeled off at an angle of 90° in a width of 1 cm, and the peel strength was measured, and a UTM (Universal Testing Machine) was used as a measuring equipment.

Roughness (Ra) measurement

In the examples, a stylus type surface roughness meter (Taylor & Hobson) was used for roughness measurement, and a center line average (Ra (Center line average, Roughness average)) was used as an evaluation index for surface roughness.

[Example]

After performing the pre-etching solution, etching solution, post-etching solution, and rust prevention solution treatment using the composition of Table 1 below, the physical properties were measured by the physical property measurement method described above.

As the material, CCL (Copper clad laminate, EM-285) and 36 μm-thick copper foil (Iljin Material) were used. The composition of each treatment solution is shown in Table 1, and the treatment conditions of each treatment solution are 25°C for pre-etching solution, immersion for 30 seconds, 25°C for etching solution, immersion for 1 minute, 25°C for post-etching solution, immersion for 30 seconds, and rust prevention solution. Was immersed at 25°C for 30 seconds.

The properties of the coated copper obtained by the examples above are listed in Table 1.

As can be seen from Examples 1 to 8 of Table 1 below, in the case of performing all of the pre-etching, etching, post-etching and rust prevention treatment of the present invention, the etching rate was 0.4 µm/min or more, the roughness was 0.4 µm or more, and the adhesion was 0.6 It can be seen that it has excellent properties of more than kgf/cm.

In addition, as can be seen from Example 9, it can be seen that the present invention has a rather low etching rate, roughness, and adhesion when pre-etching is not performed, but this also belongs to an aspect of the present invention.

In addition, it can be seen that the overall etching rate, roughness, and adhesion are somewhat inferior to the case where the amine component is not added even after pre-etching, but it can be seen that it is significantly increased compared to the prior art.

In addition, Fig. 1 shows the etched surface of the copper plate of Example 2 of the present invention, showing very dense and high-density roughness, showing excellent properties such as adhesion to the resin of the present invention.

[Comparative Example]

As a comparative example, when etching was performed at 25° C. for 1 minute using conventional sulfuric acid (10% by weight) and hydrogen peroxide (3% by weight), followed by no post-etching (Comparative Example 1), sulfuric acid (Comparative Example 2) ) And hydrochloric acid (Comparative Example 3), the etching rate in Comparative Example 1 was 1.02 μm/min, the roughness (Ra) was very low as 0.21 μm, and the adhesion was very low as 0.18 kgf/cm. In Example 2, the etching rate was 1.05 µm/min, roughness 0.23 µm, and adhesion 0.21 kgf/cm, showing a heat-cleaning effect in almost the same category, and also in Comparative Example 3, 1.05 µm/min, 0.23 µm and adhesion were 0.25 kgf/cm It shows a very poor effect, and thus is shown as the excellence of the present invention.

With respect to Comparative Example 2, FIG. 2 shows the structure of the surface of the etched copper plate, which shows that the density of the roughness is low and is formed large, and the surface condition is poor and the surface area is poor, such as fine particles attached to the surface. .

The substances of the terms used in Table 1 are as follows.

-PI: Polyethylene imine

-EDA: Ethylene diamine

-BTA: Benzotriazole

-MEA: Monoethanolamine

-TA: Tolytriazole

The present invention described above is merely exemplary, and those of ordinary skill in the art to which the present invention belongs will appreciate that various modifications and other equivalent embodiments are possible. Therefore, it will be appreciated that the present invention is not limited to the form mentioned in the detailed description above. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

Therefore, the spirit of the present invention is limited to the described embodiments and should not be defined, and all things that are equivalent or equivalent to the claims as well as the claims to be described later fall within the scope of the spirit of the present invention. .

Claims (6)

As a method of forming roughness by etching a metal surface to improve adhesion between a metal surface selected from copper and its alloy material and a resin layer,
(S1) pre-etching step; (S2) roughness forming step;
(S3) post-etching step; And (S4) a rust prevention step,
The pre-etching includes contacting a pre-etching solution containing an organic peroxide, an inorganic acid, and a residual amount of water;
The roughness formation is any one or two or more components selected from (a) copper chloride, (b) organic acid, (c) inorganic acid, (d) alkali metal halide, (e) benzotriazole and alkali metal formate, and (f) And an etching step of forming by treating with an etching solution containing a residual amount of water;
The post-etching is a method for forming a surface roughness of a copper-based metal by contacting a post-treatment etching solution containing an alkali metal salt.
delete delete The method of claim 1,
The method further includes a post-etching step after the etching step, wherein the post-etching step is formed by contacting a post-treatment etching solution containing a chlorine-based salt to form a surface roughness of a copper-based metal.
The method of claim 1,
The pre-etching solution further comprises any one or two or more compounds selected from hydrochloric acid, polyethyleneimine, and ethylenediamine.
The method of claim 4,
The method is a method for forming a roughness of a copper-based metal surface, wherein the post-etching treatment liquid further comprises any one or two or more components selected from glycolic acid and monoalkanolamine.

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