JPH11310883A - Surface treating agent for copper based material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oxide film having excellent discoloration preventing effect and adhesive property to a copper based material by using a surface treating agent composed of an aq. solution containing at least one kind selected from a polyoxyalkylene nonionic surfactant and a phosphoric ester anionic surfactant and having specified pH. SOLUTION: The aq. solution having pH 1-7 is provided. The surfactant is preferably one kind selected from ethylenediaminetetrapolyoxyalkylene ether, polyoxyalkylene phenyl phenol ether and the like and the content of the surfactant is 0.01-5 g/l, an inorganic acid and/or an organic acid is blended to adjust pH 1-7 and alkali metal salt of the acid used for the adjustment of pH is contained as a pH buffer and after the contact with the surface treating agent for copper based material, the copper base material is heated at 50-500 deg.C. The treatment of the copper based material is carried out by dipping, spraying, brush coating or the like. The oxide film having remarkably excellent adhesive property is formed by heating after surface treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surface treating agent for copper-based materials and a method for surface-treating copper-based materials.

[0002]

2. Description of the Related Art A lead frame is a sheet-like component used for assembling a semiconductor chip. A semiconductor chip is mounted on a die pad portion, wire-bonded to a lead portion, and then sealed with a resin. A chip is formed.

Usually, the lead portion of the lead frame is made of copper or a copper alloy, or is formed with a copper or copper alloy plating film. In the semiconductor manufacturing process, various processes such as partial silver plating of a lead frame, plating peeling of unnecessary portions after silver plating, mounting of a semiconductor chip, wire bonding, resin sealing, etc. are performed.
During these processes, the lead frame may be temporarily stored or moved for processing. In order to prevent discoloration of the copper metal part, the anti-tarnish treatment is performed. Have been.

Conventionally, benzotriazole derivatives, mercaptobenzothiazole derivatives, imidazole derivatives, amines, and the like have been used as discoloration inhibitors for copper metal. In recent years, however, various improvements have been made to improve performance. I have. For example, a rust inhibitor composition for copper comprising benzotriazole or a benzotriazole derivative, a polyester-based plasticizer, and a solvent (Japanese Patent Application Laid-Open No. 1-212782), a benzotriazole or a benzotriazole derivative, a phosphoric acid-based plasticizer, and a solvent Rust preventive composition for copper (JP-A-1-219183), a treatment solution containing a 2-position long-chain alkylimidazole compound and copper ions (Japanese Patent Publication No. 5-69914), 5,6-dimethyl. 1H
Copper discoloration preventing solution containing benzotriazole and / or 2-mercaptopyrimidine and an inorganic acid and / or an organic acid (Japanese Patent No. 2550436), 5-methyl-1H
Benzotriazole and / or 5,6-dimethyl-1H
A copper discoloration preventing liquid (Japanese Patent No. 2687195) in which an EDTA chelating agent is added to an acidic solution containing a benzotriazole derivative selected from benzotriazole and an inorganic acid and / or an organic acid has been reported.

However, when the discoloration preventing treatment of copper metal is performed using these treatment agents, when heat is subsequently applied to the metal subjected to the discoloration preventing treatment, an oxide film having extremely poor adhesion is formed on the surface. There is a problem that the formed oxide film is easily peeled off from the unoxidized copper metal material.

[0006] Since the lead frame is usually heated in various steps such as mounting of semiconductor chips, wire bonding, and resin encapsulation, the lead metal is subjected to a discoloration preventing treatment using a conventional discoloration preventing agent. Tends to form an oxide film having poor adhesion, and as a result, peeling may occur between the sealing resin and the copper metal portion, resulting in incomplete resin sealing. For this reason, there is a problem that moisture or the like invades from a defective portion of the sealing resin and the internal circuit is destroyed, thereby significantly reducing the reliability of the semiconductor component.

Furthermore, the use of an organic solvent among the above discoloration inhibitors has a problem that it is not preferable in working environment and occupational health.

[0008]

SUMMARY OF THE INVENTION The main object of the present invention is to:
A copper-based material surface treatment agent containing no organic solvent,
By providing a treatment agent that exhibits an excellent discoloration prevention effect on copper-based materials, and that has an oxide film formed when heat is applied after surface treatment and has very good adhesion. is there.

[0009]

Means for Solving the Problems The present inventor has made intensive studies to solve the problems of the prior art as described above. As a result, when surface treatment of a copper-based material is performed using an acidic aqueous solution containing at least one surfactant selected from a specific nonionic surfactant and an anionic surfactant, excellent discoloration prevention is achieved. It has been found that, at the same time that the effect is exhibited, the oxide film formed when heated is very excellent in adhesion. Further, after the treatment with the surface treatment agent, by performing a heat treatment under certain conditions, an oxide film having extremely good adhesion is formed, and thereafter, heat is applied to the treated product. Also found that the adhesion of the oxide film hardly decreased,
Here, the present invention has been completed.

That is, the present invention provides the following surface treating agent for copper-based materials and a method for surface-treating copper-based materials.

(1) p-containing at least one surfactant selected from a polyoxyalkylene type nonionic surfactant and a phosphate ester type anionic surfactant
A surface treating agent for a copper-based material comprising an aqueous solution of H1 to H7.

(2) The surfactant is ethylenediaminetetrapolyoxyalkylene ether, polyoxyalkylenephenyl phenol ether, polyoxyalkylene bisphenol A ether, rosin polyalkylene glycol ester, polyoxyethylene alkyl ether phosphate, polyoxyethylene Alkyl ether phosphate alkali metal salt, polyoxyethylene phenyl ether phosphate, polyoxyethylene phenyl ether phosphate alkali metal salt, polyoxyethylene alkyl phenyl ether phosphate, and polyoxyethylene alkyl phenyl ether phosphate Item 2. The surface treating agent for copper-based materials according to item 1, which is at least one selected from alkali metal salts.

(3) The surfactant content is 0.01 to 5
g / l, mixed with an inorganic acid and / or an organic acid.
Item 3. The surface treating agent for a copper-based material according to the above item 1 or 2, adjusted to 1 to 7.

(4) The surface treating agent for a copper-based material according to any one of the above items 1 to 3, further comprising an alkali metal salt of an acid used for pH adjustment as a pH buffer.

(5) A method for treating a surface of a copper-based material, comprising contacting the surface-treating agent for a copper-based material described in any one of the above items 1 to 4 with a copper-based material.

(6) After contacting the surface treating agent for a copper-based material described in any of the above items 1 to 4 with the copper-based material,
A surface treatment method for a copper-based material, wherein a heat treatment is performed at 0 to 500 ° C.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The surface treating agent for a copper-based material of the present invention contains at least one surfactant selected from a polyoxyalkylene type nonionic surfactant and a phosphate ester type anionic surfactant. PH 1 to 7 aqueous solution.

Preferred examples of the polyoxyalkylene type nonionic surfactant include ethylenediaminetetrapolyoxyalkylene ether, polyoxyalkylene phenyl phenol ether, polyoxyalkylene bisphenol A ether, rosin polyalkylene glycol ester and the like. . As the alkylene oxide in the polyoxyalkylene contained in these nonionic surfactants, alkylene oxides having 2 to 3 carbon atoms such as propylene oxide and ethylene oxide are preferable, and these may be used alone or in combination of two or more. The connection order may be block or random. In particular, those having 10% or more of ethylene oxide (EO) in alkylene oxide are preferable from the viewpoint of good solubility. The nonionic surfactant preferably has a number average molecular weight of about 1,000 to 8,000.

Preferred examples of the phosphate type anionic surfactant include phosphate esters such as polyoxyethylene alkyl ether phosphate, polyoxyethylene phenyl ether phosphate, and polyoxyethylene alkyl phenyl ether phosphate. And alkali metal (Na, K, etc.) salts of these phosphate esters. These phosphate esters are obtained by phosphorylating nonionic polyoxyalkylene surfactants such as polyoxyethylene alkyl ether, polyoxyethylene phenyl ether, and polyoxyethylene alkyl phenyl ether. The degree of chemical conversion may be any of monoester, diester, and triester, and may be appropriately selected according to solubility and the like. As the alkyl group in the polyoxyethylene alkyl ether, those having about 10 to 20 carbon atoms are suitable, and specific examples include lauryl, stearyl, oleyl and the like. As the alkyl group in the polyoxyethylene alkylphenyl ether, one having about 5 to 10 carbon atoms is preferable, and specific examples thereof include octyl and nonyl. As these nonionic polyoxyalkylene surfactants, HLB before phosphorylation is 5 to 15%.
Examples in which ethylene oxide (EO) is added to a certain extent can be given.

In the surface treating agent of the present invention, a surfactant selected from the above polyoxyalkylene type nonionic surfactants and phosphate ester type anionic surfactants is used alone or in combination of two or more. be able to. The content of the surfactant is preferably about 0.01 to 5 g / l.

The treating agent of the present invention is used after adjusting the pH to about 1 to 7, preferably about 1 to 4. By setting the pH in such a range, discoloration of the surface of the object to be treated is prevented, moisture is easily removed, and generation of dry spots and the like can be suppressed. Further, the solubility of the surfactant is also improved.

The pH is adjusted by adjusting the acid and alkali hydroxide (Na,
K). Examples of the acid used for pH adjustment include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and organic acids such as formic acid, acetic acid, lactic acid, tartaric acid, succinic acid, citric acid, and gluconic acid. They can be used alone or in combination of two or more. Of these acids,
An inorganic acid is preferred, and sulfuric acid is more preferred, because it is inexpensive and the wastewater treatment is easy.

The surface treating agent of the present invention may further comprise a pH buffer, if necessary, for suppressing pH fluctuation.
The salt of the acid used for pH adjustment can be blended. Examples of the kind of the salt include an alkali metal (Na, K) salt and the like. The amount of the salt may be an amount capable of exerting an effect as a pH buffer, and usually,
What is necessary is just to mix | blend so that it may become a density | concentration of about 1-5% in aqueous solution as a surface conditioner.

In order to use the surface treating agent of the present invention stably for a long period of time, it is preferable to use an inorganic acid for pH adjustment and blend an alkali metal salt of the inorganic acid as a pH buffer. More preferably, sulfuric acid is used for pH adjustment, and an alkali metal salt of sulfuric acid is blended as a pH buffer.

The surface treating agent of the present invention can be prepared by dissolving each component in water and then adjusting the pH to a predetermined range. In addition, a predetermined amount of a surfactant, an acid or the like may be added in advance. A concentrated solution prepared in advance may be prepared and diluted at the time of use. When a concentrated solution is used, a small amount of alcohols such as methanol, ethanol and isopropyl alcohol may be blended in order to improve the solubility of the surfactant component. Usually, the amount of the alcohol is preferably such that the alcohol concentration becomes about 1% or less when the concentrated liquid is diluted to have the surface treatment agent concentration in the used state.

In order to treat a copper-based material with the treating agent of the present invention, the surface treating agent of the present invention may be brought into contact with a copper-based material to be treated. The method of contacting is not particularly limited, and various methods such as immersion, spraying, brush coating, and the like can be appropriately selected.

The processing conditions are such that the temperature of the processing solution is 10 to 80 ° C.
The contact time may be about 2 seconds to 10 minutes.

As the copper-based material to be treated, copper metal or copper alloy can be used. Further, a material having a plating film formed of copper or a copper alloy on the surface can also be treated. There is no particular limitation on the type of copper alloy, and for example, copper alloys such as brass and bronze, various copper alloys for lead frames, and the like can be processed. Various types of copper alloys for lead frames are known, and any of them can be used without limitation. For example, as alloy metals other than copper, Fe, Ni, Zn, Sn, T
A copper alloy containing i, Mg, Zr, Si, P, Cr, Ag and the like in a total amount of about 5% by weight or less can be exemplified.

A thin organic film at the molecular level is formed on the surface of the copper-based material treated in this manner, and the discoloration of the copper-based material can be suppressed in an atmosphere at room temperature to about 250 ° C. As a result, for example, the lead frame including the copper-based material portion, in the manufacturing process of the semiconductor component, after the electrolytic peeling of the partial silver plating, mounting of the internal circuit,
Discoloration on the surface of the copper-based material is suppressed during temporary storage and transportation until formation.

When the copper-based material treated with the surface treating agent of the present invention is heated, a dense and strong oxide film is formed on the surface. The oxide film to be formed has good adhesion with a copper-based material that has not been oxidized.For example, after treating the copper surface of a lead frame with the treatment agent of the present invention, a step of drying the treated product, When heated by various processes such as subsequent mounting of circuit components, bonding for circuit formation, formation of resin sealing, etc., since the adhesion of the oxide film to be formed is good, the resin sealing portion A semiconductor product having high reliability can be obtained without generating defects.

Further, the copper-based material treated with the surface-treating agent before the oxide-based film is formed by heating the copper-based material treated with the surface-treating agent of the present invention during the above-described various treatment steps. Is heated in advance to form an oxide film, whereby the adhesion of the oxide film can be further improved.

This heat treatment may be performed usually at a temperature of about 50 to 500 ° C. for about 2 seconds to 10 hours. Preferably, when the heating temperature is relatively low within the above range, that is, at a temperature of about 200 ° C. or less, the heating may be performed for about 10 minutes to 10 hours. can do. The heating atmosphere may be usually in the air. There is no particular limitation on the heating method, and a method of indirectly heating a material such as hot air heating by a dryer, a hot air circulation oven, an infrared heater, a method of contacting a heating device such as a hot plate, or a direct heat Any method such as a typical heating method may be used.

By performing the heat treatment in this manner, a dense and highly adherent oxide film is formed on the surface of the copper-based material treated with the surface treating agent of the present invention. In the case where an oxide film is formed in this manner, even if heat is applied in the subsequent semiconductor product manufacturing process, the oxidation does not easily proceed because the dense oxide film has already been formed, and The formation of the oxide film is prevented, and the adhesion of the oxide film does not decrease.

[0034]

The copper-based material treated with the surface treating agent of the present invention hardly causes discoloration and hardly causes dry spots. And even when heat is applied in the semiconductor manufacturing process,
Since the adhesiveness of the oxide film to be formed is very good, no defect occurs in the resin-sealed portion of the semiconductor product and the semiconductor product has high reliability.

Further, when an oxide film is formed by performing a heat treatment after the treatment with the surface treating agent of the present invention, an oxide film having particularly good adhesion is formed, and a highly reliable semiconductor product is obtained. Obtainable.

[0036]

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

Example 1 A 2.5 × 5.0 cm copper plate (phosphorous deoxidized copper material) whose surface was polished was used as a test piece, subjected to alkali degreasing and acid activity, and subjected to a surface treatment agent (aqueous solution) having the following composition. ) And heated in an electric furnace (300 ° C., in the atmosphere) for 5 minutes.

Thereafter, an adhesive tape (trade name: Scotch 810) was attached to the surface of the formed oxide film, and the film was peeled perpendicularly to the surface of the oxide film to evaluate the adhesion of the oxide film. The same test was performed on a test piece (blank) not immersed in the surface treatment liquid.

As for the discoloration preventing effect, the test piece before the heating test was placed in pure water and boiled for 5 minutes, and then the presence or absence of discoloration was visually evaluated.

The above results are shown in Table 1 below.

* Surface treatment agent (Product 1 of the present invention) Dipotassium sulfate: 1 g / l Ethylenediaminetetrapolyoxyalkylene ether (trade name: Pepol D-304, manufactured by Toho Chemical): 0.5 g / l pH: 1.5 (Adjusted with sulfuric acid) (Product 2 of the present invention) Polyoxyethylene phenyl ether phosphate (trade name: phosphanol LP-700 manufactured by Toho Chemical): 1.0 g / l pH: 2.5 (adjusted with sulfuric acid) Invention product 3) Polyoxyethylene alkyl ether phosphate (trade name: phosphanol RS-710, manufactured by Toho Chemical): 0.1 g / l pH: 2.2 (adjusted with sulfuric acid) (Product of the invention 4) polyoxyethylene Phenylphenol ether (trade name: TS-2000, manufactured by Toho Chemical): 0.2 g / l ethylenediaminetetrapolio Xyalkylene ether (trade name: Pepol D-304, manufactured by Toho Chemical): 0.3 g / l pH: 2.0 (adjusted with sulfuric acid) (Product 5 of the present invention) Polyoxyethylene bisphenol A ether (trade name: bisol 18EN) : 0.5 g / l polyoxyethylene phenyl ether phosphate (trade name: phosphanol LP-700, manufactured by Toho Chemical): 0.5 g / l pH: 1.8 (adjusted with sulfuric acid) Invention product 6) Rosin polyalkylene glycol ester (trade name: DRA-1500, manufactured by Toho Chemical): 0.5 g / l polyoxyethylene phenyl ether phosphate (trade name: phosphanol LP-700, manufactured by Toho Chemical): 0 0.3 g / l pH: 2.0 (adjusted with sulfuric acid) (Comparative product 1) Benzotriazole derivative Content-type discoloration inhibitor (Trade name: Top rust inhibitor 511, manufactured by Okuno Pharmaceutical): 20 ml / l (Comparative product 2) Benzotriazole derivative-containing type color-change inhibitor (Trade name: OPC Defenser, manufactured by Okuno Pharmaceutical) ): 5 ml / l

[0042]

[Table 1]

As is clear from the above results, when the copper-based material was surface-treated using the surface treatment agent of the present invention,
An excellent effect of preventing discoloration is exhibited, and the adhesion of an oxide film formed when heated thereafter is also very good.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // H01L 23/50 H01L 23/50 A

Claims (6)

[Claims] 1. A pH 1 to 1 containing at least one surfactant selected from a polyoxyalkylene type nonionic surfactant and a phosphate ester type anionic surfactant.
7. A surface treating agent for a copper-based material, comprising an aqueous solution of 7. 2. A surfactant comprising ethylenediaminetetrapolyoxyalkylene ether, polyoxyalkylenephenylphenol ether, polyoxyalkylenebisphenol A ether, rosin polyalkylene glycol ester, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl. Ether phosphate alkali metal salt, polyoxyethylene phenyl ether phosphate, polyoxyethylene phenyl ether phosphate alkali metal salt, polyoxyethylene alkyl phenyl ether phosphate, and polyoxyethylene alkyl phenyl ether phosphate alkali The surface treating agent for a copper-based material according to claim 1, which is at least one selected from metal salts. 3. A surfactant content of 0.01 to 5 g / l.
And an inorganic acid and / or an organic acid are blended to adjust the pH to 1 to 7.
The surface treatment agent for a copper-based material according to claim 1, wherein the surface treatment agent is adjusted to: 4. The surface treating agent for a copper-based material according to claim 1, further comprising an alkali metal salt of an acid used for pH adjustment as a pH buffer. 5. A method for treating a surface of a copper-based material, comprising contacting the surface-treating agent for a copper-based material according to claim 1 with a copper-based material. 6. After contacting the surface treating agent for a copper-based material according to any one of claims 1 to 4 with the copper-based material, 50 to 5 times.
A surface treatment method for a copper-based material, wherein the surface treatment is performed at 00 ° C.