KR100211927B1 - Method and composition for underplating copper alloy and iron-nickel alloy with copper-nickel alloy - Google Patents

Abstract

Disclosed are a semiconductor lead frame (PCB), a printed circuit board (PCB) and a base plate composition of a connector, a base plate method, and a plated body made of a copper alloy and an iron-nickel alloy. Base plating composition is copper 15-25g / Nickel 10-20g / It consists of an aqueous solution included. The base plating layer consists of a copper-nickel alloy layer and may further plate a palladium layer, a gold layer or a palladium-gold alloy layer on the base plating layer. The base plating layer forming method is performed by dipping a plated body made of a copper alloy or an iron-nickel alloy material in a base plated composition solution, and then flowing a current of 2.5-5.0 ASD through the plated body. According to the present invention, the copper nickel alloy base plated layer of copper alloy and iron-nickel alloy material is much more flexible than the conventional nickel plated layer, has excellent adhesion and corrosion resistance, and is more than the two-step process of nickel plating after conventional copper plating. It is an advanced plating that is much more workable and free of pollution.

Description

Copper-nickel alloy not plating composition and not plating method of copper alloy and iron-nickel alloy material

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper-nickel alloy base plating composition and a base plating method of a copper alloy or an iron-nickel alloy material, and more particularly, to a semiconductor lead frame and a printed circuit board made of a copper alloy or an iron-nickel alloy material. The present invention relates to a copper-nickel alloy base plating composition and a base plating method which can be used for PCB) and connectors.

Conventionally, semiconductor lead frames made of copper or iron-nickel alloys have been mainly plated with silver or tin-lead alloys.

However, as a problem of silver plating, it is pointed out that the silver plating solution is made of harmful pollutants such as cyan compounds, along with discoloration of silver plated portions, formation of copper oxide films, resin bleeding during die contact, and poor adhesion during molding. come. In addition, tin-lead plating solution also had a problem that contains a large amount of lead, a heavy metal material.

In addition, nickel plated copper plated and palladium or gold plated on copper circuit boards and connectors are basically used, but satisfactory performance and efficiency are not obtained.

Recently, nickel plating is not used instead of silver plating solution and tin-lead alloy plating. However, this nickel base plating also does not show complete characteristics. For example, due to the large internal stress of the nickel plated layer, a fine crack occurs in the underlying nickel plated layer during trimming and trimming in the semiconductor process, resulting in corrosion resistance, solderability, and adhesion with other plating layers. There is a problem of lowering the reliability of semiconductor lead frames, printed circuit boards, connectors and the like.

Particularly in the case of an iron-nickel alloy material (Alloy # 42), Si and Ca components contained in the material (42%, Fe 56%, Mn 0.8%, Si 0.3%, Ca 0.035%, P 0.025%) Because of this, chemical activation is difficult, and if nickel is immediately plated on this material, the adhesion force is reduced due to Fe contained in this material, and thus there are many problems such as corrosion and deterioration in solderability due to micro cracks.

In order to overcome these problems, it is urgent to develop a new base plating solution that excludes silver plating and tin-lead alloy plating and also has much better characteristics than the base nickel plating currently in use.

On the other hand, nickel plating, then palladium or gold plating are carried out after copper plating on copper alloy and iron-nickel alloy material, but this is complicated by 3 or 4 step process, which reduces working efficiency and is caused by electrical stress with each plating layer. There is a problem that poor adhesion and fine cracks occur. In addition, there is a problem of causing pollution due to the use of toxic cyan compound during copper plating.

Therefore, the present inventors have studied diligently to solve the above problems of the conventional base plating layer applied to the copper alloy and iron-nickel alloy material, and as a result, the corrosion resistance, adhesion, The copper-nickel alloy plating composition was developed with much greater flexibility to complete the present invention.

It is an object of the present invention to provide a copper-nickel alloy base plating composition applied to copper alloy and iron-nickel alloy materials.

Another object of the present invention is to provide an underlying plating layer formed from the underlying plating composition of the present invention.

Still another object of the present invention is to provide a method of forming a copper-nickel alloy under plated layer of the present invention.

The base plating composition for achieving the above object is copper 15-25 g / Nickel 10-20g / It consists of an aqueous solution included.

Preferably, 30-100 g / of at least one conductive salt in the copper-nickel alloy base plating composition Complexing agent 0.5-20g / , Surface improver 0.1-5g / , And stress reducing agent 0.05-0.2 g / Included.

The base plated layer for achieving the above another object is made of a copper-nickel alloy.

Method for forming a base plated layer to achieve the above another object is a) copper 15-25g / l and nickel 10-20g / Dipping a plated body made of a copper alloy or an iron-nickel alloy material in a plating composition solution consisting of an aqueous solution containing a; And

B) flowing a current of 2.5-5.0 ASD (ampere per square decimeter) to the plated body to form a base plating layer having a thickness of 0.8-1.5 mu.

The palladium layer, gold layer or palladium-gold alloy layer may further be plated on the base plating layer.

Hereinafter, the present invention will be described in more detail.

Copper of the present invention is supplied in an appropriate salt form depending on the nickel concentration to be alloyed and the type of conductive salt, and examples of the salt include copper sulfate pentahydrate, cupric pyrophosphate, cupric carbonate, or mixtures thereof. It may be reacted with a suitable conductive salt beforehand. The concentration of copper metal in the composition is 15-25 g / l, preferably 20 g / l.

Nickel may be used, for example, nickel sulfate hexahydrate, nickel carbonate tetrahydrate, amine nickel sulfate, or a mixture thereof, and the like may be added to the composition after reacting with the electromotive salt in advance so as not to precipitate or thicken in the plating composition. Do. The metal nickel concentration is 10-20 g / l, preferably 15 g / l. to be. The conductive salt should be appropriately selected depending on the type of metal salt of copper and nickel to be alloyed. Metasulfonic acid salts, citrates or sulfates may be used, for example methanesulfonic acid, potassium citrate, citric acid, sodium citrate, ammonium sulfate, Sodium sulfate, sulfuric acid or mixtures thereof.

The conductive salts must be well combined with the metal and for this to be sufficiently reacted with the metal, in some cases after the reaction with the metal separately. Conductive salt concentration is 30-100g / , Preferably 50-80 g / to be.

The alloyed copper and nickel may be combined well alone, but in other cases, it is preferable to use an appropriately selected complexing agent to complex these metals to make stable plating. Examples of complexing agents include gluconic acid, ethylenediaminetetrasodium acetate dihydrate, N, N ', N''-tritosyldiethylenetriamine, or mixtures thereof. The amount of complexing agent used is 0.5-10 g / And preferably 0.7-7 g / 1.

As surface improvers, 6-oxo-3,9-diabicyclo [9.3.1] pentadeca-1 (15), 11-13-triene, potassium tartrate sodium, N, N-diethyl-1,3-dia Minopropane or a mixture thereof is used, and the amount of use is 0.1-5 g / , Preferably 0.5-2.0 g / to be.

Examples of the stress reducing agent include a, a'-dichloro-2,6-lutidine, S (-)-N- (1-pentylethyl) benzylamine, azodicarboxyl dipiperidide or mixtures thereof. Usage is 0.05-0.2g / , Preferably 0.1-0.15 g / Used as a concentration.

If the concentrations of copper and nickel metals are higher than 25 and 20 g / l, respectively, the metal deposition rate is fast and the current efficiency is too high, so that the plating of the high current part is carried out and the activity of the metal is also increased. Cracks occur, while the concentrations of copper and nickel metal are 15 and 10 g / When lower, the current efficiency is low, so plating is not performed well at low current sites, and pin holes or pits are easily generated on the plating surface; Conductive salt concentration is 100g / If higher, the alloy ratio is lowered or the current efficiency is increased, resulting in cracking or uneven plating of metal particles due to the high internal stress of the plating layer formed by plating of the high current portion, and the concentration of the conductive salt is 30 g / If it is lower than the low current portion plating is not good, corrosion resistance, adhesion and the like is inferior; The concentration of the complexing agent is 10 g / Greater than or equal to 0.5 g / Lower the plating surface, as well as the balance of the plating liquid is broken, the life of the plating liquid is shortened; The concentration of the surface improver or stress reducer was 5 and 0.2 g / The higher the organic matter, the more the plating liquid becomes turbid or the equilibrium of the plating liquid is easily broken, and the plating surface also has a narrow current range, so that both high and low currents are not plated, or pin holes and pits are severely generated, and surface improvers or If the concentration of the stress reducing agent is lower than 0.1 and 0.05 g / l, respectively, cracking occurs badly and pits occur due to the stress of the nickel plating layer.

Since the plating composition according to the present invention uses an appropriate conductive salt and a complexing agent according to the type of metal salt, it has excellent stability and is very insensitive to impurities, thereby achieving uniform plating even when used for a long time.

Meanwhile, the plating layer forming method according to the present invention is as follows.

The plating composition is prepared by directly dissolving copper, nickel, conductive salts, complexing agents, and other additives, which are plating compositions, directly in water or by reacting a metal salt with an electrically conductive salt or a complexing agent, and then dissolving in water to sufficiently react. The copper-nickel alloy base plating solution according to the present invention has a specific gravity of 15-20 Be '(Baume') and has an acidity of about pH 1-3.

While maintaining the plating composition at room temperature, a cathode such as a plated body and a platinum network, which is a cathode, is immersed, and a current of 2.5-5.0 ASD, preferably 3-4 ASD, is flown to the plated body to have a thickness of 0.8-.1.5 μm. Copper-nickel alloy base plated layer is formed. If the current density is higher than 5.0 ASD, the plating surface burns, and if the current density is lower than 2.5 ASD, the plating is not good or pits occur on the plating surface. Thereafter, palladium plating, gold plating or palladium-gold alloy plating is performed on the base plating layer.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

However, the scope of the present invention is not limited only to the following Examples.

Example 1

The following components were added to distilled water to prepare a plating composition.

Copper sulfate 5 receiver 80 g /

Nickel Sulfate Heptahydrate 55g /

Ammonium Sulfate 60g /

Sodium sulfate 40g /

Gluconic Acid 5g /

6-oxo-3,9-diabicyclo [9,3,1] pentameca-

1 (15), 11-13-triene 0.2g /

a, a'-dichloro-2,6-lutidine 0.07 g /

The above-described plating composition was electroplated by applying a semiconductor lead frame, a printed circuit board, or a connector as a cathode, and a current of 3 ASD was applied to obtain a highly uniform and flexible 60-40 copper-nickel alloy plating layer. Palladium plating, gold, plating, and palladium-gold alloy plating were selectively plated on this plating layer to obtain good results, respectively.

Example 2

The following components were added to distilled water to prepare a plating composition.

50 g of cupric pyrophosphate

Amine nickel sulfate 40g /

Methanesulfonic Acid 55g /

N, N'N ''-tritosyldiethylenetriamine 2g /

N, N-diethyl-1,3-diaminenopropane 0.1 g /

0.05 g / S (-)-N (1-phenylethyl) benzylamine

Plating under the same conditions as in Example 1 with the above prepared plating composition resulted in a very even and flexible copper-nickel base plated layer. Thereafter, palladium plating, gold plating or radium-gold alloy plating were performed in the same manner as in Example 1 to obtain good results.

Example 3

The following components were added to distilled water to prepare a plating composition.

45 g / cupric carbonate

Nickel Carbonate Tetrahydrate 27g /

Citric acid 70g /

Potassium Citrate 28g /

Ethylenediaminetetraacetic acid

Sodium Salt Dihydrate 5g /

Sodium Potassium Tartrate 3g /

Azodicarboxylic dipiperidide 0.1 g /

As a result of plating under the same conditions as in Example 1 with the plating composition prepared above, a very uniform and flexible copper-nickel alloy base plated layer was obtained, and then palladium, gold, or palladium-gold alloy plating was performed as in Example 1. The plating layer which was excellent in corrosion resistance, solderability, and adhesiveness was obtained.

Claims (12)

15-25g / Copper, 10-20 g / Nickel, 30-100g / Of conductive salt, 0.5-10g / , Complexing agent, 0.1-5g / Surface improver and 0.05-0.2g / Copper-nickel alloy base plating composition of the copper alloy or iron-nickel alloy material in the form of an aqueous solution containing a stress reducing agent of the. The copper alloy or iron-nickel of claim 1, wherein the copper is added to the aqueous solution in the form of a copper sulfate pentahydrate, cupric pyrophosphate, cupric carbonate, and a mixture thereof. Base plating composition of alloy material. The copper alloy or iron-nickel alloy of claim 1, wherein the nickel is added to the aqueous solution in the form of one selected from the group consisting of nickel sulfate hexahydrate, nickel carbonate tetrahydrate, amine nickel sulfate and mixtures thereof. Base plating composition of the material. The copper alloy or iron-nickel alloy of claim 1, wherein the conductive salt is selected from the group consisting of methanesulfonic acid, potassium citrate, citric acid, sodium citrate, ammonium sulfate, sodium sulfate, sulfuric acid and mixtures thereof. Base plating composition of the material. The method of claim 1, wherein the complexing agent is selected from the group consisting of gluconic acid, ethylenediamine tetraacetic acid sodium salt dihydrate, N, N ', N' '-tritosyldiethylenetriamine, and mixtures thereof. Not plating composition of copper alloy or iron-nickel alloy material. The method of claim 1, wherein the surface improving agent is 6-oxo-3,9-dithiabicyclo [9.3.1] pentadeca-1 (15), 11-13-triene, potassium tartrate sodium, N, N-di A base plating composition of copper alloy or iron-nickel alloy material, characterized in that it is selected from the group consisting of ethyl-1,3-diaminopropane and mixtures thereof. The method of claim 1, wherein the stress reducing agent , '-Dichlor-2,6-lutidine, S (-)-N- (1-phenylethyl) benzylamine, azodicarboxylic dipiperidide and mixtures thereof Base plating composition of copper alloy or iron-nickel alloy material. A) 15-25 g / Copper, 10-20 g / Nickel, 30-100g / Of conductive salt, 0.5-10g / , Complexing agent, 0.1-5g / Surface improver and 0.05-0.2g Dipping a plated body made of a copper alloy or an iron-nickel alloy into a solution of a plating composition in the form of an aqueous solution containing a stress reducing agent of; B) flowing a current from the plated body to 2.5-5.0 ampere per square decimeter (ASD) to form a base plated layer having a thickness of 0.8-1.5 microns. The method of claim 8, wherein palladium plating, gold plating or palladium-gold alloy plating is performed on the copper-nickel alloy underlying plating layer. A plated body comprising a plated body made of a copper alloy or an iron-nickel alloy material prepared according to the method of claim 8 and a base plated layer formed of a copper-nickel alloy on the plated body. The plated body according to claim 10, wherein the plated body is a semiconductor lead frame, a printed circuit board (PCB), or a connector. The plated material according to claim 10, wherein a palladium, gold or palladium-gold alloy is further plated on the base plating layer.