Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
  • C23C22/58—Treatment of other metallic material
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C13/00—Alloys based on tin
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/48—After-treatment of electroplated surfaces
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
  • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
  • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
  • H05K3/3457—Solder materials or compositions; Methods of application thereof
  • H05K3/3478—Applying solder preforms; Transferring prefabricated solder patterns

Definitions

• the present invention relates to a surface treatment agent for metals, particularly Sn and Sn alloys, and a surface treatment method using the same. Furthermore, the present invention provides an electronic component, a substrate, a solder ball, a solder powder, a ball grid array using the solder ball, a solder paste using the solder powder, a solder paste using the solder powder, and the like. Related mounting products. Background art
• soldering is a technique for joining objects using a substance having a relatively low melting point, and is widely used in modern industry for joining and assembling electronic devices.
• the commonly used solder is Sn-Pb alloy, and its eutectic composition (63% Sn-balance Pb) has a low melting point of 183 ° C. Since it is performed in C, it hardly causes thermal damage to electronic components and substrates.
• the Sn-Pb alloy has excellent solderability, and also has the excellent characteristics that it solidifies immediately upon soldering and does not easily crack or peel even when vibration is applied to the soldered part. ing.
• electronic devices are formed of a synthetic resin such as an outer frame or a board and a metal such as a conductor or a frame. When disposed, they are not incinerated and are mostly buried in the ground. Can be In recent years, rain falling on the ground tends to be acidic (acid rain), and contaminating groundwater by eluting solder for electronic devices buried underground has become a problem. For this reason, the use of lead-free solder (lead-free solder) is rapidly moving, especially in the electronics industry.
• the external lead terminals of electronic components are mainly soldered (90% Sn-balance Pb) to respond to lead-free use. Is desired. Candidates for lead-free soldering are roughly classified into pure Sn, Sn-Ag (Cu), Sn-Zn, and Sn-Bi. Each has its own strengths and weaknesses. Has not been reached yet.
• the Sn-Zn-based alloy is advantageous in that it does not need to change the current equipment process because the melting point is close to that of a conventional Sn-Pb-based alloy. Also, the mechanical strength of the plating film is excellent and the cost is also excellent. However, since Zn is an active metal species and is easily oxidized, the Sn-Zn alloy has very poor solder wettability, so it is considered that the possibility of practical application is the lowest at this time.
• solder paste is used for surface mounting electronic components on a substrate, and its use has been increasing in recent years.
• the solder paste is generally a solder alloy powder as a main component, and is obtained by adding a flux containing an adhesive, an activator, a thixotropic agent ij, a surfactant, a solvent, and the like.
• As lead-free solder pastes Sn_Ag (Cu) -based alloys, Sn_Zn-based alloys, and Sn-Bi-based alloys are being studied. Eutectic temperature is considered a promising alternative.
• solder paste using Sn-Zn-based alloy as the solder powder undergoes an oxidation reaction with the activator contained in the flux, resulting in remarkable solder wettability and storage stability.
• an inert gas atmosphere is required during reflow.
• Patent Document 1 Japanese Patent Application No. 2002-304554
• Patent Document 2 Japanese Patent Application No. 2002-304554
• a surface treatment agent characterized by containing salt was proposed.
• Patent Document 2 Japanese Patent Application Laid-Open No. 7-188942 particularly proposes an antioxidant characterized by comprising diphenyl phosphate and / or diphenyl phosphite. ing.
• Patent Document 2 Japanese Patent Application Laid-Open No. 7-188942
• the present inventors have conducted intensive studies on the suppression of oxidation of metals, particularly Sn and Sn alloy surfaces, and as a result, they have two or more phosphonic acid groups in one molecule and have an ester bond in the molecule.
• Surface treatment with a surface treatment agent containing a total of 0.1 Olg / L or more of one or more of compounds containing no and / or salts thereof imparts oxidation resistance and improves solder wettability. I found that I can do better.
• the solder paste containing the surface-treated Sn alloy solder powder showed a remarkable improvement in storage stability. Furthermore, it was found that the occurrence of whiskers was significantly suppressed in the surface-treated Sn and Sn alloy.
• the present invention is as follows.
• a metal surface treatment agent characterized by the following:
• the compound having two or more phosphonic acid groups in one molecule and having no ester bond in the molecule and / or a salt thereof is represented by the following formula (1), (II) or (III) And / or a salt thereof with an alkali metal salt, an ammonium salt, or an amine compound, wherein the metal surface according to any one of (1) to (3) above, Processing agent.
• x 1 —x 3 and ⁇ 1 — ⁇ X 3 each represent a hydrogen atom which may be the same or different, or a lower alkyl group having 115 carbon atoms.
• R 2 and R 4 each represent the following groups (A) which may be the same or different;
• R 3 represents the following groups (A) or lower alkyl groups having 15 carbon atoms; Represents an integer of 1 to 3.
• x represents a hydrogen atom or a lower alkyl group having 115 carbon atoms
• ⁇ represents a hydrogen atom.
• And represents a lower alkyl group having 1 to 5 carbon atoms, a hydroxyl group, or an amino group.
• solder ball according to (8) is disposed on an electronic component and connected to a circuit board.
• Examples of the metal to be treated with the surface treatment agent of the present invention include Fe, Ni, Co, Cr, Cu, Zn, Sn, Al, Mg, Ti, Ag, and Au, and these may be alloys. Les ,. In particular, Sn and Sn alloys are preferred. As a Sn alloy, a lead-free Sn alloy is more preferred because of problems such as environmental pollution. Examples of the Sn alloy that does not include a mouth include a solder alloy that includes one or more of Zn, Bi, Cu, In, Ag, and Sb in Sn.
• the amount of the compound and / or its salt is less than 0.01 g / L, the effect is small. Conversely, there is no upper limit on the amount of addition because there is no deterioration in the properties even if the amount of added koji is too large. More preferably, it is 0.1-10 Og / L.
• the surface treatment agent of the present invention uses a compound containing no ester bond in the molecule, a sufficient antioxidant effect can be obtained even at a relatively high temperature where the ester bond is not decomposed by the heat treatment. . Therefore, lead-free soldering temperature is relatively higher than before
• the detailed mechanism of a compound having two or more phosphonic acid groups in one molecule is not clear as compared with a compound having two or more phosphonic acid groups in one molecule. Was found to be excellent.
• the number of phosphonic acid groups in one molecule is preferably 26 from the viewpoint of cost.
• x 1 —x 3 and Y 1 —Y 3 each represent a hydrogen atom which may be the same or different, or a lower alkyl group having 115 carbon atoms.
• R 2 and R 4 each represent the following groups (A) which may be the same or different;
• R 3 represents the following groups (A) or lower alkyl groups having 15 carbon atoms; Represents an integer of 1 to 3.
• X represents a hydrogen atom or a lower alkyl group having 115 carbon atoms
• Y represents a hydrogen atom, a lower alkyl group having 115 carbon atoms, a hydroxyl group, or an amino group.
• ditrilotrismethylenephosphonic acid and the like are particularly preferable because they are commercially available.
• ethylenediaminetetrakismethylenephosphonic acid diethylenetriaminepentakismethylenephosphonic acid and the like are particularly preferred.
• compound represented by the general formula ( ⁇ ) 1-hydroxyethane-1,1,1-diphosphonic acid and the like are particularly preferred.
• the alkali metal salt of the above compound is preferably a sodium salt, a potassium salt or the like.
• a salt with a compound triethylamine salt / triethanolamine salt and the like are preferable.
• the surface treatment agent of the present invention can be used by dissolving a compound having two or more phosphonic acid groups in one molecule and containing no ester bond in the molecule, and / or a salt thereof in a solvent. it can.
• the solvent used is not particularly limited as long as it is soluble.
• water is preferred in consideration of the power S, solubility, cost, and the like, which include polar solvents such as water and alcohols and glycols.
• the oxidation resistance of the surface to be treated is further improved.
• the pH of the surface treatment agent is more preferably pH 15 in consideration of the influence on the material and the like.
• the pH adjuster generally available acids and alkalis can be used.
• the oxidation resistance of the surface to be treated is further improved.
• the amount of surfactant added to the surfactant is preferably 0.1 to 10 g / L.
• surfactant one or more kinds of commercially available anionic, cationic, nonionic and amphoteric surfactants can be appropriately selected and used.
• anionic surfactants include sulfate ester type, sulfonate type, ester phosphate salt type, and sulfosuccinate type
• cationic surfactants include quaternary ammonium salt type and amine salt.
• Nonionic surfactants such as higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, polyoxyethylene polyoxypropylene block polymers, polyoxyethylene polyoxypropylene block polymers of ethylenediamine, and higher aliphatic surfactants
• Preferred are ethylene oxide adducts of amines and ethylene oxide adducts of aliphatic amides
• the amphoteric surfactants are preferably amino acid type, betaine type and the like.
• anionic and nonionic When the pH is used in the range of 5 or less, it is preferable to appropriately select and use one or more of anionic and nonionic.
• nonionic surfactants among the nonionic surfactants, the polyethylene glycol type is particularly preferred, and higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, and polyoxyethylene polyoxypropylene are particularly preferred.
• Block polymers and the like can be particularly preferably used, and among the anionic surfactants, sulfate ester type and phosphate ester type are particularly preferable.
• the surface treatment agent of the present invention may contain an additive in an amount that does not impair the original properties for the purpose of imparting desired performance.
• the additive include a preservative, a pH buffer, and the like, and those conventionally known can be used.
• the surface treatment of the metal using the surface treatment agent of the present invention may be any method that forms a film on the surface of the metal.
• a method in which the metal is simply immersed in the surface treatment agent a surface treatment
• Examples of the method include applying the agent using a shower or an apparatus such as an air coater, a blade coater, a rod coater, a knife coater, a gravure coater, a reverse coater, or a cast coater.
• the shape of the metal to be surface-treated with the surface treatment agent of the present invention may be any shape such as a line, a plate 'band' foil, a particle, and a powder. It can process electronic components, substrates, solder balls, solder powder, etc.
• the surface treatment agent of the present invention By using the surface treatment agent of the present invention, the surface of the conductor of the connection terminal portion of the electronic component or the substrate is surface-treated, or the surface of the conductor is plated, and then the surface is treated, so that the oxidation resistance is excellent and the solder wets. An electronic component or a substrate having improved performance can be obtained.
• Solder balls using the Sn alloy treated with the surface treatment agent of the present invention have excellent oxidation resistance, are arranged as ball grid arrays as electrical connection members, and are arranged on electronic components and connected to circuit boards. It can be used favorably as a mounted product.
• the Sn alloy powder is treated with the surface treatment agent of the present invention, and a flux containing an adhesive, an activator, a thixotropic agent, a surfactant, a solvent, and the like is added thereto to form a solder paste. You can also use it. This solder paste has a remarkable effect of improving the storage stability. Conventionally known adhesives, activators, thixotropic agents, surfactants, and solvents can be used.
• Examples 1 to 14 and Comparative Examples 1 to 5 Fifteen types of aqueous solutions containing two or more phosphonic acid groups in one molecule and containing no compound having an ester bond in the molecule or a salt thereof as an active ingredient were prepared (Examples 1 to 14 and Comparative Example 1). . Table 1 shows the breakdown.
• This substrate was Sn plated with a thickness of about 5 xm (plating bath: Tincoat K (manufactured by Nikko Metal Plating Co., Ltd.), plating conditions: cathode current density 2A / dm 2 , temperature 20 ° C , Liquid flow and force sword rocking).
• the Sn-plated substrate (hereinafter referred to as Sn substrate) contains a compound having two or more phosphonic acid groups in one molecule and containing no ester bond in the molecule, or a salt thereof. After being immersed in the solution at a bath temperature of 60 ° C. for 10 seconds, it was washed with water and dried to obtain a test substrate.
• Table 1 shows the test results.
• solderability (zero cross time) with lead-free solder was measured by the meniscograph method under the following measurement conditions. .
• solderability zero cross time
• lead-free solder was measured using a meniscus. It was measured by the cograph method in the same manner as in the term of thermal oxidation resistance.
• a substrate treated with an isopropanol solution containing lg / L of dodecylphosphonic acid on the above Sn substrate (however, without water washing after the surface treatment, Comparative Example 2), Japanese Unexamined Patent Publication No. 7-188942 discloses a base material treated with an aqueous solution containing lgZL phosphonate lgZL (Comparative Example 3), the untreated Sn base material (Comparative Example 4), and the Sn base material.
• a substrate (Comparative Example 5) treated with the surface treatment agent aqueous solution containing 0.1 g / L of diphenyl phosphate was also evaluated. Table 1 also shows the test results.
• Plating bath manufactured by Nikko Metal Plating Co., Ltd., plating conditions: cathodic current density 3 A / dm 2 , temperature 35 ° C., pH 4.0, liquid flow and force swinging).
• Sn—Zn-plated substrate (hereinafter referred to as Sn—Zn substrate) was added to the solutions prepared in Examples 1-11, Comparative Examples 1-3, and Comparative Example 5 at a bath temperature of 60 ° C. After immersion for 10 seconds, the substrate washed with water, dried, and untreated were used as test substrates.
• Example 114 After aging was performed on these test substrates in the same manner as in Example 114 and Comparative Example 115, the solderability was measured. Table 2 shows the test results.
• a surface treatment agent (lwt% isopropanol of monodioctadecynyl phosphate) described in Japanese Patent Application No. 2002-304554 was used for the untreated Sn—Zn substrate. And the treated substrate (Comparative Example 11) was also evaluated. Table 2 shows the test results.
• Example 29 The Sn-plated substrate treated in the same manner as in Example 7 and the substrate not subjected to the surface treatment were allowed to stand in a constant temperature and humidity atmosphere of 85 ° C. and 85% humidity for 24 hours. After that, the substrate was sufficiently dried, and the surface was observed with a scanning electron microscope (SEM). In the case where the surface was not treated, many whiskers were observed (Comparative Example 12). No whiskers were observed in the treated products (Example 29).
• a compound having two or more phosphonic acid groups in one molecule and having no ester bond in the molecule, and / or one or two or more of salts thereof in total of 0.1 Olg / L or more By treating the surface of the metal with a surface treatment agent containing it, it can impart oxidation resistance and improve solder wettability. By adjusting the pH of this surface treatment agent to 5 or less, and further adding a surfactant of 0.01 to 10 g / L, the oxidation resistance is improved.
• the storage stability of the solder paste containing the Sn alloy solder powder subjected to the surface treatment using the surface treatment agent of the present invention is remarkably improved. Further, by treating Sn and the Sn alloy with the surface treatment agent of the present invention, the generation of whiskers can be significantly suppressed.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mechanical Engineering (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Electric Connection Of Electric Components To Printed Circuits (AREA)
• Chemical Treatment Of Metals (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Electroplating Methods And Accessories (AREA)
• Other Surface Treatments For Metallic Materials (AREA)

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• 2005
  • 2005-02-22 CN CN2011103259870A patent/CN102424965A/zh active Pending
  • 2005-02-22 KR KR1020067019566A patent/KR100802878B1/ko active IP Right Grant
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