KR100553840B1 - Method for manufacturing thin copper film for printed circuit board - Google Patents

Abstract

The present invention relates to a copper foil laminated on a printed circuit board to form a variety of circuits, in an acidic electrolysis bath, the copper foil as a cathode and electrolyzed near the limit current density to smooth the convex portion 11 or smooth surface of the copper foil. In the manufacturing method of the copper foil for printed circuit boards which form the roughening process layer of the coin complex 12 on the surface, the contact area of the copper foil to-be-adhered surface is added by adding an inorganic polyanion more than molecular weight 2000 or more to an electrolysis bath. In addition, the adhesive strength and heat resistance of the insulating substrate are increased, and the adhesive strength of the copper foil and the resin substrate is constantly maintained so that the electrical properties and acid resistance are improved as well as the fall of copper is minimized.

Copper Foil, Convex, Coin Complex, Inorganic Polyanion

Description

Method for manufacturing copper foil for printed circuit board {Method for manufacturing thin copper film for printed circuit board}

1 is an electron micrograph showing a convex portion of a copper foil according to a general technique,

2 is an electron micrograph showing a state in which the complex is electrodeposited on the convex portion of the copper foil according to the prior art,

3 is an electron micrograph showing a state in which the complex is electrodeposited on the convex portion of the copper foil according to the present invention.

Explanation of symbols on the main parts of the drawings

11 convex portion 12: coin complex

The present invention relates to a copper foil laminated on a printed circuit board to form various circuits, and more particularly, to a method for manufacturing a copper foil for a printed circuit board which can increase the surface area of the copper foil to increase the adhesive strength as well as to improve the electrical properties. It is about.

In general, a printed circuit board is an electronic device used for precision control circuits such as electric devices and electronic communication equipments. After wiring a network through copper foil on one or both sides of an insulating board such as a synthetic resin, an IC or an electronic component is mounted on a board. It is manufactured by arranging lamps, electrically wiring them, and coating them with an insulator.

In addition, in the case where a printed circuit board is to be formed in a multilayer, copper foil is laminated on an insulating substrate under high temperature and high pressure, screen printed circuit patterns, and then etched with a copper chloride solution or the like to form a network, and then the surface of the copper foil is After the roughening layer is formed, elements such as semiconductor devices are mounted.

At this time, the copper foil for a printed circuit board is formed on the surface to be bonded to form a roughened layer of a plurality of protrusions of the coin complex to increase the surface area as much as possible, for example, insulation substrate and adhesive performance, that is, high temperature heating, wet treatment, welding, In the process of chemical treatment, the conditions that sufficient adhesive strength should be maintained must be met.

Therefore, as shown in FIGS. 1 and 2, as a means for increasing the adhesive strength of the copper foil, when the mountain-shaped convex portion 11 is formed on the copper foil, the coin 12 is electrodeposited onto the convex portion 11, When the copper foil does not have the mountain-shaped convex part 11, the coin complex 12 is electrodeposited on the smooth surface of copper foil, and forms a roughening process layer.

However, in the electrokinetic decomposition bath, as a result of forming the roughened layer of the coin complex 12 in the convex part 11, as shown in FIG. 2, a coin is spread over a wide range along the mountain and the valley of the convex part 11, as shown in FIG. Since the complex 12 is electrodeposited in a mixed state, there is a problem in that the adhesive surface with the resin substrate is reduced in the copper foil and the adhesion performance with the insulating substrate is lowered and may fall.

On the other hand, in the method of forming the coin complex 12 in the convex part 11 of copper foil, in Japanese special application (54-38053) and Japanese special application (53-39327), arsenic, antimony, A technique in which elements of group 6B of the periodic table, such as bismuth and selenium, are electrolyzed before and after the limit current density has been proposed.

However, when arsenic is included in the electrolysis bath, since a certain amount of arsenic is contained in the coin complex in the electrolysis process, the environmental and health effects of arsenic during the regeneration and other processing of copper foil or the disposal of the etching solution in which arsenic is dissolved are used. There is a disadvantage that serious problems arise.

On the other hand, as a method of forming the coin complex 12 in the convex part 11 of copper foil, the method of using the bath which added a trace amount of benzoquinolines of Japanese special application (56-411196), and Japan special publication (62) -56677) using molybdenum, vanadium or both baths, and Japanese JP-A (6-169169, 8-236930) baths containing chromium, tungsten or protons, Japan The method of pulse plating of Unexamined-Japanese-Patent No. 63017597 and 58-164797, or including vanadium, zinc, iron, nickel, cobalt, chromium, etc. has been proposed.

By the way, these methods do not contain toxic elements such as arsenic does not adversely affect the environment and health, but the electrodepositions 12 are mixed in the acid and bone of the convex portion 11 formed on the copper foil electrodeposited The adhesive strength with the insulating substrate was lowered, and there was a fear that the complex 12 was detached.

Accordingly, the present invention has been made to solve the above problems, the printed circuit to increase the surface area of the copper foil to improve the adhesive strength with the insulating substrate as well as to improve the electrical characteristics of the printed circuit board. The objective is to provide the manufacturing method of the copper foil for board | substrates.

The present invention for achieving the above object, the printing in which the copper foil as a cathode in an acidic electrolysis bath and electrolyzed near the limit current density to form a roughened layer of a coin complex on the convex portion or smooth surface of the copper foil. In the method for producing a copper foil for a circuit board, an inorganic polyanion ion having a molecular weight of 2000 or more containing tungsten is further added to the plating ion of the electrolysis bath, or a molecular weight 2000 containing tungsten element and phosphorus selected from the plating ion of the electrolysis bath. The above-mentioned inorganic polyanion is further added, or the inorganic polyanion having a molecular weight of 2000 or more containing tungsten element and silicon selected from the plating ions of the electrolysis bath is further added.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is an electron micrograph showing a state in which the complex is electrodeposited on the convex portion of the copper foil according to the present invention, wherein the copper foil is used as a cathode in an acidic electrolysis bath and electrolyzed near a limit current density to convex portions 11 of the copper foil. Or an inorganic polyanion having a molecular weight of 2000 or more containing tungsten in the plating ion of the electrolysis bath, in the method of manufacturing a copper foil for a printed circuit board forming a roughened layer of the coin complex 12 on a smooth surface. Or an inorganic polyanion having a molecular weight of 2000 or more containing tungsten element and phosphorus selected in the plating ion of the electrolysis bath or an inorganic polyanion having a molecular weight of 2000 or more containing tungsten element and silicon selected in the plating ion of the electrolysis bath It is characterized by further addition.

First, the plating solution composition and plating conditions included in the acidic electrolysis bath according to the present invention are as shown in Table 1, and a detailed description thereof will be omitted, but instead of arsenic used in the plating solution, an environmentally friendly molecular weight of 2000 or more It is added that the inorganic polyanion was further added.

[Table 1] Plating Solution Composition

Copper ion Sulfuric acid Inorganic Polyanions Plating temperature Current density Plating time 5 ~ 150g / ℓ 10-200 g / ℓ 0.001 ~ 5g / ℓ 20 ~ 50 ℃ 5 ~ 100A / dm 1-30 sec

In addition, as a result of further adding an inorganic polyanion in the acidic copper electrolysis bath to form a roughened layer, as shown in FIG. 3, nucleation is suppressed in the process of depositing the coin 12 on the convex portion 11 of the copper foil. Of course, the development of the dendrite structure is suppressed to form a round shape of the particles.

In addition, as a source of the inorganic polyanion, it is possible to use paratungstic acid, metatungstic acid 12-phosphorous tungstic acid, or 12-molybdenum tungstic acid, sodium salts or ammonium salts thereof. At this time, the inorganic poly anion is suitably in a concentration ratio of 0.001 to 5 g / l, preferably 0.01 to 2 g / l, in the plating ion in the electrolytic decomposition bath.

Of course, the present invention can also be applied to the convex portion 11 is formed on the outer surface of the copper foil, it can be applied to electrolytic copper foil, rolled copper foil, etc. in which the convex portion 11 is not formed on the outer surface of the copper foil. Of course.

Hereinafter, with reference to the accompanying drawings, examples and comparative examples according to the present invention will be described in detail as follows.

Example 1

A current density of 20 A / d is applied to the adhered surface of a 35 µm thick electrolytic copper foil using a 30 ° C aqueous solution containing 100 g / l copper sulfate pentahydrate, 200 g / l sulfuric acid, and 0.001 to 5 g / l sodium metatungstate. After plating for 6 seconds at 2 m 2, plating was performed at a current density of 20 A / dm 2 for 10 seconds using a 45 ° C. electrolyte containing 50 g / l copper ions and 100 g / l sulfuric acid.

Subsequently, the copper foil obtained in Example 1 was heated and pressurized to an epoxy resin (not shown) to produce a copper-clad laminate, and then the adhesive strength of the copper foil and the resin was measured using UTM, and the dropping of the copper powder was measured after etching. Was observed using an optical microscope, and the results are shown in Table 2.

At this time, as a result of measuring the adhesive strength of the copper foil and the resin ten times, the average value was found to be very good as about 2.25kgf / ㎝, there is no fall of copper powder, it can be seen that the electrodeposition efficiency of the complex is very improved. there was.

That is, as shown in Fig. 3, since the fused complex 12 having a uniform size is concentrated on the peak of the convex portion 11 of the copper foil, the adhesion area with the epoxy resin (not shown) is greatly increased compared to Fig. 2. It can be estimated that the adhesion performance is improved.

In addition, when sodium metatungstate was added at a concentration ratio of less than 0.001 g / l in the acidic electrokinetic bath, there was no effect due to the increase in adhesive strength, copper powder dropped after etching, and sodium metatungstate 5.0g It was found that only the economic burden increased before the effect of increasing the adhesive strength under the conditions of the concentration ratio of / l or more.

Example 2

A 30 ° C aqueous solution containing 100 g / l copper sulfate pentahydrate, 200 g / l sulfuric acid, and 0.001 to 5 g / l 12-silicon tungstic acid was used as an electrolysis bath, and a current density of 20 A / After plating for 6 seconds at dm 2, plating was performed at 20 A / dm 2 for 10 seconds using a 45 ° C. electrolyte containing 50 g / l copper ions and 100 g / l sulfuric acid.

Subsequently, the copper foil obtained in Example 2 was heated and pressurized to an epoxy resin to produce a copper foil laminated plate, and then the adhesive strength of the copper foil and the resin (not shown) was measured using UTM, and the surface of the resin after etching the copper foil was measured by an optical microscope. Using copper was observed the fall off phenomenon, the results are shown in Table 2.

At this time, as a result of measuring the adhesive strength of the copper foil and the resin over 10 times, the average value was found to be very good as about 2.20kgf / cm, it was found that there is no falling of copper powder, the electrodeposition efficiency of the coin complex is improved. .

That is, since the slightly larger sized complexes 12 are formed uniformly in the peaks of the convex portion 11 of the copper foil, the adhesion area with the epoxy resin (not shown) is compared with that of FIG. It can be inferred that the adhesion performance with the resin substrate is improved greatly.

In addition, when 12-silicon tungstic acid was added at a concentration ratio of less than 0.001 g / l in the acidic electrokinetic bath, there was no effect of increasing the adhesive strength, and copper powder dropped after etching, and 5.0 g of 12-silic tungstic acid was generated. It was found that only the economic burden was increased before the effect of increasing the adhesive strength under the conditions of the concentration ratio of / l or more.

Comparative Example 1

As an example containing no additives, an aqueous solution of 30 ° C containing 100 g / l copper sulfate pentahydrate and 200 g / l sulfuric acid was used as an electrolysis bath, and the current density was 20 A / dm 2 at the adhered surface of the 35 µm thick electrolytic copper foil. After plating for a second, the plating was carried out at 20 A / dm 2 for 10 seconds using a 45 ° C. electrolyte containing 50 g / l of copper ions and 100 g / l of sulfuric acid.

Subsequently, the copper foil obtained in Comparative Example 1 was heated and pressurized to an epoxy resin to produce a copper-clad laminate, and then the adhesive strength of the copper foil and the resin was measured using UTM, and the drop of copper was etched after etching the resin surface using an optical microscope. It measured, and the result is shown in Table 2.

At this time, as a result of measuring the adhesive strength of the copper foil and the resin 10 times, the average value was measured about 1.93kgf / cm was found to be significantly reduced compared to Example 1.2, the convex portion of the coin complex is not rounded It was found that the fall of the copper powder caused by the shape caused by this, the electrodeposition efficiency is reduced.

Comparative Example 2

A 30 ° C aqueous solution containing 100 g / l copper sulfate pentahydrate, 200 g / l sulfuric acid, and 3 g / l arsenic acid was used as an electrolysis bath, and plated on the adhered surface of a 35 µm thick electrolytic copper foil with a current density of 20 A / dm 2 for 6 seconds. After that, plating was performed at 20 A / dm 2 for 10 seconds using a 45 ° C. electrolyte containing 50 g / l of copper ions and 100 g / l of sulfuric acid.

Subsequently, in Comparative Example 2, the copper foil was heated and pressurized to an epoxy resin to prepare a copper-clad laminate, and then the adhesive strength of the copper foil and the resin was measured using UTM, and the fall of copper was measured using an optical microscope. The results are shown in Table 2.

At this time, the adhesive strength of the copper foil and the resin was measured 10 times, and the average value was about 2.21kgf / cm, which is similar to Example 1.2, and copper powder did not occur, and electrodeposition efficiency was good, but arsenic was about 100 ppm. It was found to have adverse environmental and health effects.

Therefore, by further adding an inorganic polyanion having a molecular weight of 2000 or more in the acidic electrolysis bath to form a roughened layer of coin complex, the coin complex 12 electrodeposited on the surface to be bonded of the copper foil has rounded particles as shown in FIG. Formed in the form it can be seen that the surface area of the copper foil is relatively increased.

[Table 2] Property measurement result of copper foil

division Additive in electrolyte Adhesive strength (kgf / cm) Equal fall Example 1 Sodium metatungstate 2.25 none Example 2 12-silicon tungstic acid 2.20 none Comparative Example 1 No addition 1.93 has exist Comparative Example 2 arsenic acid 2.21 none

 As described above, according to the manufacturing method of the copper foil for printed circuit board according to the present invention, since the roughened layer of the round coin-formed body is formed on the to-be-bonded surface of the copper foil, the contact area of the to-be-bonded surface of copper foil is relatively In addition, the adhesive strength and heat resistance of the insulating substrate are increased, and the adhesive strength of the copper foil and the resin substrate is always kept constant, thereby improving electrical characteristics and acid resistance and minimizing the dropping of copper.

Claims (5)

delete In the manufacturing method of the copper foil for printed circuit boards which uses copper as a cathode in an acidic electrolysis bath, and electrolyzes in the vicinity of a limit current density, and forms the roughening process layer of the coin complex in the convex part or the smooth surface of copper foil,    A method for producing a copper foil for a printed circuit board, wherein an inorganic poly anion having a molecular weight of 2000 or more containing tungsten element and phosphorus selected in the plating ion of the electrolysis bath is added at a concentration of 0.001 to 5.0 g / l. In the manufacturing method of the copper foil for printed circuit boards which uses copper as a cathode in an acidic electrolysis bath, and electrolyzes in the vicinity of a limit current density, and forms the roughening process layer of the coin complex in the convex part or the smooth surface of copper foil,    A method for producing a copper foil for a printed circuit board, wherein an inorganic poly anion having a molecular weight of 2000 or more containing tungsten element and silicon selected from the plating ions of the electrolysis bath is added at a concentration of 0.001 to 5.0 g / l. delete The method according to claim 2 or 3, wherein the inorganic poly anion, A method for producing a copper foil for a printed circuit board, comprising: an electrolyte containing at least one selected from vanadium, zinc, iron, nickel, cobalt, and chromium.

Images