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
  • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
  • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
  • C23C18/31—Coating with metals
  • C23C18/42—Coating with noble metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K1/00—Soldering, e.g. brazing, or unsoldering
• • 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
  • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
  • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
  • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
  • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
  • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
  • H01L21/76841—Barrier, adhesion or liner layers
  • H01L21/76871—Layers specifically deposited to enhance or enable the nucleation of further layers, i.e. seed layers
  • H01L21/76874—Layers specifically deposited to enhance or enable the nucleation of further layers, i.e. seed layers for electroless plating

Definitions

• the present invention relates to a substitution type electroless plating solution.
• Replacement plating solutions are applied to electronic components and are typically used to form sub-0.2 micron thin films. This is to protect the joint at the time of mounting the electronic component with a thin gold film.
• the gold-coated part of the electronic component that has been subjected to the replacement plating in the plating process is replaced with another electronic component using solder or the like in the mounting process. After being joined with components, they are eventually assembled as electronic devices such as personal computers and mobile phones.
• solder joint characteristics of replacement metal plating has often been taken up as a problem. This is because the area of the solder joints has been reduced in order to meet the demand for smaller and lighter electronic devices, as well as increased opportunities for electronic devices to move, resulting in mechanical shocks such as falling and compression. And exposure to deformation pressure. In order to prevent disconnection of electronic circuits, higher solder joint strength is required than before.
• the displacement metal plating is mainly used to prevent the corrosion of the underlying metal (for example, copper, nickel, cobalt, metal, radium, etc.) and to ensure the wettability when the solder is melted. If the mold is not correctly attached, the solder joint strength will be reduced. In other words, if the replacement metal plating is not performed correctly, the underlying metal (eg, copper, nickel, etc.) may be oxidized. The adhesive layer formed between the solder and the solder may not provide sufficient strength. The gold thin film formed on the base metal diffuses into the solder when the solder is melted, and the interfacial alloy layer is formed by the metal and the solder. Conventionally, how to prevent oxidation of the underlying metal during the displacement Technical considerations are being made.
• the underlying metal for example, copper, nickel, cobalt, metal, radium, etc.
• substitutional plating is a plating method that uses the difference in ionization tendency between gold in the plating solution and the underlying metal (eg, copper or nickel).
• the underlying metal eg, copper or nickel.
• the underlying metal which has a large ionization tendency, becomes ions and dissolves in the plating solution.
• the replacement plating method does not require a reducing agent.
• electroless gold plating that requires a reducing agent is also called reduction plating, and is used when a thicker film than the substitution type is required, usually when it is 0.2 microns or more. ing.
• substitution reduction plating in which a reducing agent is added to a substitution plating solution to cause a substitution reaction and a reduction reaction to proceed simultaneously. It is interpreted that this method not only deposits gold due to the action of the reducing agent, but also prevents oxidation of the underlying metal, resulting in improved solder joint strength.
• Japanese Patent Application Laid-Open No. 2000-210973 introduces an electroless plating solution to which a reducing agent such as hydrazine and hydroxylamine is added.
• No. 59 discloses an electroless gold plating solution to which a reducing agent for hypophosphite and a hydrazine compound is added.
• the displacement reducing plating solution to which such a reducing agent is added has a problem in that the analysis and replenishment of the reducing agent in the plating solution must be constantly performed during the plating operation. Since the reducing agent is a substance that decomposes by heating the plating bath and emits electrons at this time, this decomposition reaction is a necessary chemical reaction to be used by being added to the plating solution. This indicates that the reducing agent decomposes as plating proceeds, and the amount of effective reducing agent gradually decreases. Therefore, the work of analyzing the amount of the reducing agent remaining in the plating bath and replenishing the decomposed amount is an indispensable work for the displacement reduction type plating solution.
• Japanese Unexamined Patent Publication No. 2001-144144 discloses an undercoat metal in a plating solution. Techniques related to electroless plating solutions that contain a complexing agent that does not dissolve metal and a gold deposition inhibitor that suppresses excessive etching of the underlying metal are introduced. This technique aims at suppressing excessive etching of the underlying metal, and no study has been made on preventing oxidation of the underlying metal.
• the underlying metal eluted by the substitution reaction cannot be stably dissolved, and the underlying metal tends to re-deposit together with the gold. It may take on a brownish hue and no longer show the original lemon yellow hue.
• the present invention provides an electroless metal plating solution that effectively prevents oxidation of a metal surface to be coated without using a reducing agent and forms a gold film having good solder joint characteristics.
• an object of the present invention is to provide a substitutional electroless plating solution that does not require analysis and replenishment of the reducing agent at the time of use.
• the substitutional electroless gold plating solution according to the present invention comprises a water-soluble gold salt, a conductive improver, an iminodiacetate type chelating agent, and an organic compound containing two or more nitrogen atoms in the main chain or ring.
• a surface oxidation inhibitor, and a solvent as a balance.
• the present inventors added various compounds to a plating solution comprising a water-soluble gold salt, a conductivity improver and a complexing agent to obtain a substitution type electroless gold plating solution, and formed the plating solution with the plating solution. Solder bonding was performed on the gold-plated film, and the bonding strength was measured.
• the present inventors have found that an organic compound containing two or more nitrogen atoms in its main chain or ring is effective as a surface oxidation inhibitor on the surface of copper, Huckel and the like widely used for electronic components.
• the present invention has been reached.
• the substitutional electroless gold plating solution according to the present invention which contains these series of surface oxidation inhibitors as essential components, has good soldering properties of the resulting gold-plated film despite not containing a reducing agent. It is. Since the plating solution does not contain a reducing agent, it has excellent thermal stability and does not need to constantly analyze and capture the reducing agent during the plating operation. 03 013243
• the plating solution of the present invention chelates and stably dissolves the underlying metal, the displacement reaction product (the underlying metal ion eluted when gold is deposited) accumulated by using the plating solution. However, it does not impair the color of the gold plating (lemon yellow) by being mixed into the gold-plated deposition layer, so that the plating solution can be used for a long time.
• the gold plating solution according to the present invention is hardly affected by metal ions such as copper, nickel, cobalt, and palladium, which are accumulated in the plating solution.
• the plating layer can be formed stably over a long period of time.
• FIG. 1 is a diagram showing a substrate for evaluating solder joint characteristics.
• FIGS. 2A and 2B are cross-sectional views showing a plating substrate according to the present invention.
• FIG. 3 is a diagram showing the solder balls used for evaluating the solder joint characteristics.
• Figure 4 is a diagram showing the outline of the shear-strength measurement of a solder pole.
• FIG. 5 is a diagram showing a peeled state when bonding is good.
• FIG. 6 is a diagram showing a peeled state in a case where bonding is defective.
• FIG. 7A and 7B are diagrams showing the results of the Auger measurement of Example 1.
• FIG. 7A and 7B are diagrams showing the results of the Auger measurement of Example 1.
• FIG. 8A and 8B are diagrams showing the results of the Auger measurement of Comparative Example 1.
• FIG. 8A and 8B are diagrams showing the results of the Auger measurement of Comparative Example 1.
• FIG. 9 is a diagram showing the ESC A measurement results of Example 3.
• the main components of the plating solution according to the present invention include a water-soluble gold salt, a conductivity improver, a chelating agent having an imino diacetate structure, and two or more nitrogen atoms in the main chain or ring.
• a surface oxidation inhibitor composed of an organic compound.
• gold plating means 24K gold plating (purity 98% or more) and various metal species ranging from 24K gold plating to 14K (purity 56-60%) (for example, Ni, (Co, Ag, In, etc.).
• Water-soluble gold salts include potassium gold (I) cyanide, potassium gold (II) cyanide, sodium gold (I) chloride, titanium (II) chloride, ammonium ammonium sulfite, and gold sulfite. Potassium, sodium gold sulfite, and gold thiosulfate A mixture of sodium and gold thiosulfate has good properties. Particularly preferred in the present invention are cinnamate primary gold reamers and sodium gold sulfite. As a concentration of the water-soluble gold salt in the plating solution, a range of 0.1 to 10 gZL can be used, and a particularly preferable range is 0.5 to 5 g / L.
• Examples of the conductivity improver include inorganic compounds such as boric acid, borate, phosphoric acid, phosphate, sulfuric acid, sulfate, thiosulfate, nitrate, and chloride salt, citric acid, quinate, and malic acid.
• inorganic compounds such as boric acid, borate, phosphoric acid, phosphate, sulfuric acid, sulfate, thiosulfate, nitrate, and chloride salt, citric acid, quinate, and malic acid.
• Organic compounds such as benzoate, glycine, glycine salts, glutamic acid, glutamate, and mixtures thereof exhibit good properties.
• the compound is a salt compound
• the compound
• Particularly preferred conductivity improvers in the present invention are aliphatic polycarboxylic acids and their potassium, sodium and ammonium salts.
• the concentration of the conductivity improver in the plating solution can be in the range of 5 to 500 gZL ', and particularly preferred is in the range of 10 to 200 g / L.
• a chelating agent having an iminodiacetic acid structure is used as the chelating agent in the plating solution according to the present invention.
• Such chelating agents reduce the surface metal of the substrate to be plated, such as copper, nickel, cobalt, iron, and other metals (including alloys) to gold. JP2003 / 013243
• a chelating agent having an iminodiacetate structure capable of dissolving metals such as copper, nickel, cobalt, and iron (including alloys) as an essential component, the surface of the substrate to be plated with gold Dissolution of the metal (eg, copper, nickel, cobalt, iron, etc.) in the plating solution is promoted, and reprecipitation of these metals can be prevented.
• Chelating agents having such an iminodiacetic acid structure include ethylenediaminetetraacetic acid, hydroxyethyliminodiacetic acid, ethrotriacetic acid, hydroxyethylethylenediamine3acetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexacetic acid, and dicarboxymethyl.
• chelating agents having a strong action of stably dissolving Ni and Cu, and those containing three or more acetate units in the molecule are particularly preferred. That is, Utrilo triacetic acid, hydroxyethylethylene diamine triacetic acid, ethylene diamine tetraacetic acid, diethylene triamine pentaacetic acid, triethylene tetraamine hexaacetic acid, and water-soluble salts thereof are particularly preferable.
• the concentration of the chelating agent having an iminodiacetic acid structure in the plating solution is used in the range of 1 to 200 gZL, particularly preferably in the range of 2 to 100 gZL.
• other chelating agents can be used in combination with the chelating agent having such an iminodiacetic acid structure, if necessary.
• those which do not substantially dissolve the underlying metal eg, copper, nickel, cobalt, etc.
• organic phosphonic acid compounds cannot stably dissolve the underlying metal eluted by the replacement reaction, and This is not suitable for the present invention because re-precipitation occurs together with gold and the resulting gold plating has poor color tone and insufficient solder joint strength.
• the surface oxidation inhibitor used in the present invention is an organic compound containing two or more, preferably three or more nitrogen atoms in the main chain or ring.
• the surface oxidation inhibitor is preferably an electron-donating compound, in which case the electron-donating property of the compound is P2003 / 013243
• the nitrogen atom present in the chain or ring has a mono-NH structure, that is, the presence of one or more mono-NH groups in the main chain or ring Is preferred.
• Such a surface oxidation inhibitor of the present invention include an aliphatic compound represented by the following formula [I] and a heterocyclic compound represented by the following formula [II]. (I)
• To shaku 4 each independently represent hydrogen, an alkyl group having 1 to 3 carbon atoms, one (C 2 H 4 ) m — NH 2 , one (C 2 H 4 ) n — OH (where m is 0 or 1 and n is 0 or 1). p is an integer of 0-4. ]
• R 5 represents hydrogen bonded to a carbon atom in the heterocyclic ring, an alkyl group having 1 to 3 carbon atoms, an amino group, or an alkylamino group having 1 to 3 carbon atoms.
• ⁇ ⁇ 4 are preferably hydrogen and methyl groups, m is 0 or 1, n is 0 or 1, and p is preferably 1-3.
• R 5 is preferably hydrogen, methyl group or amino group.
• heterocycle having a nitrogen atom and a carbon atom of one NH— group in the ring a 5-membered ring is preferable.
• the remaining four atoms of this five-membered heterocycle ie, the atoms other than the nitrogen atom of the above-mentioned NH— group
• R 5 can be bonded to this carbon atom.
• the heterocyclic compound represented by the above formula [II] may be a heteromonocyclic compound consisting of one “heterocyclic ring having a nitrogen atom or a carbon atom of one NH— group in the ring”. It may be a condensed complex ring compound in which two or more rings are formed in such a manner that the two carbon atoms therein are shared. Benzimidazole and benzotriazole are preferred specific examples of the fused heterocyclic compound.
• the surface oxidation inhibitor of the present invention is preferably an electron-donating compound
• at least one nitrogen atom containing at least three nitrogen atoms in the main chain or ring has at least one nitrogen atom.
• Compounds having one NH— structure, among them, ⁇ electron excess type aromatic compounds are particularly preferable.
• Preferred specific examples of the surface oxidation inhibitor of the present invention include the following compounds.
• Aliphatic compounds include ethylenediamine, ⁇ , ⁇ , -bis (beta-hydroxyl-ethylene-diamine, diethylenetriamine, ⁇ , ⁇ , -bis (beta-hydroxyl-oxethyl) -diethylenetriamine, triethylenetetramine, ⁇ , N'-bis (beta-hydroxixeti) ⁇ ⁇ )-triethylenetetramine, tetraethylenepentamine, ⁇ , ⁇ , -bis (betahydroxyshethyl) -tetraethylenepentamine, etc.
• Particularly preferred are those having 3 or more nitrogen atoms and at least 1 ⁇ Nitrogen is an aliphatic compound with a secondary amine structure.
• aromatic compounds examples include 2-aminovirol, 3-aminovirol, 2-aminoinodole, 3-aminoinodole, pyrazole, 3-aminovirazole, 4-aminopyrazole, 5-aminopyrazole, imidazole, and 2-aminoimida.
• Zonolle 4-amino-imidazonole, 5-amino-imidazonole, 1,2,3-triazole, 4-amino- 1,2,3-triazole, 5-amino- 1,2,3-triazonole , 1, 2, 4-triazole, 3-amino-1,2,4-triazo , 5-amino-1,2,4-triazole, tetrazole, 5-amino-tetrazonole, benzimidazonole, 2-amino-benzimidazonole, benztriazol and the like.
• aromatic heterocyclic compounds having 3 or more nitrogen atoms and a ⁇ -electron excess type.
• the ⁇ -electron excess type and the deficiency type of the heterocyclic compound are described in detail in a companion book, “Heterocyclic Chemistry, by Adrian Albert, The Anthon Press University of London, 1959,” JP-A-2000-14441. In the gazette, various nitrogen-containing compounds are listed as gold deposition inhibitors. Among them, pi-electron-deficient aromatic compounds such as pyridine and triazine cannot be used in the present invention.
• the concentration of the surface oxidation inhibitor in the plating solution can be used in the range of 5 to 50,000 ppm, particularly preferably in the range of 10 to 10,000 ppm.
• a crystallization modifier, a surfactant, and / or a buffer may be appropriately selected and added to the plating solution according to the present invention.
• Preferred crystal modifiers in the present invention include, for example, thallium and lead.
• the concentration of the crystal modifier in the plating solution is preferably 0.1 to 100 ppm, particularly preferably 1 to 50 ppm.
• Surfactants are mainly used to adjust the wettability of the plating solution to the substrate to be plated.
• a neutral, a cationic, or cationic surfactant can be used.
• the concentration of the surfactant in the plating solution can be appropriately used in the range of 1 to 1000 ppm.
• a compound having a buffering action may be used as a conductive salt component, but may be added separately.
• Phthalate, phosphate, borate, tartrate, lactate, acetate, etc. can be used in the range of 10-200 gZL.
• the substitutional electroless plating solution according to the present invention comprising the above components is placed in a bath, adjusted to a predetermined ⁇ , heated, and used.
• the pH is usually in the range 4-8, and the bath temperature is usually in the range 60-100 ° C.
• the material to be immersed in the plating solution preferably has copper or a copper alloy on the metal portion, or a nickel plating film formed on copper. Copper or a copper alloy formed by various methods such as mechanical processing such as rolling, an electroplating method, an electroless plating method, and a vapor phase plating method can be used as the covered portion.
• the nickel plating film a film formed by electroplating or electroless plating with a thickness of 0.2 to 10 ⁇ m on copper can be used as a covering portion.
• the thickness of the gold-plated thin film formed on these covered portions is usually from 0.02 to 0.4 ⁇ , preferably from 0.03 to 0.2 / zm.
• Solder balls mounted on this gold film have diameters in the range of 100 ⁇ m to 1 mm, depending on the size of the connection (pad).
• solder composition besides the conventional Sn-Pb system, various solder compositions generally referred to as Pb-free solder can be used.
• FIG. 1 shows an outline of a substrate used for evaluating solder joint characteristics in the present invention.
• the coated substrate shown in Fig. 1 has a glass epoxy substrate 1 with a length of 4 OmmX and a width of 4 OmmX and a thickness of 1 mm, and circular copper pads 2 with a diameter of 0.76 mm arranged in a grid pattern.
• the periphery of each copper pad is covered with a photo solder resist 3.
• Each copper pad 2 is formed of 12 / xm thick copper, the resist coating 3 has a thickness of 20 microns, and the opening of the copper pad 2 has a diameter of 0.62 mm.
• a substrate la (hereinafter referred to as a directly plated substrate 1a) having a 0.06 / zm-thick plating film 4 directly formed on the copper surface at the opening was obtained (Fig. 2 (a)). ).
• a nickel plating film 5 having a thickness of 5 ⁇ is formed on the copper surface of each copper pad 2 according to the conditions shown in Table 2 below, and further a thickness of 0.06 is formed on the nickel plating film 5.
• a substrate 1b on which a gold-plated film 4 of 1 m / m was formed (hereinafter, referred to as a substrate-brick-plated substrate 1b) was obtained (FIG. 2 (b)).
• Fig. 2 (a) shows a cross section of the directly plated metal substrate 1a obtained above
• Fig. 2 (b) shows a cross section of the base nickel-plated substrate 1 b obtained above.
• Solder poles 6 with a diameter of 0.76 mm are respectively placed on the surfaces of the plating films 4 on the pads of the above-mentioned direct plating substrate 1a and the base nickel plating substrate 1b. It was mounted, fused and soldered (Fig. 3), and its bonding strength was evaluated by the following method.
• solder pole 6 Pb solder and Pb free solder were used.
• Solder balls 6 were placed on the pads of the above-mentioned direct plating substrate 1a and the underlying nickel-plated substrate 1b, and the reflow soldering device (In this study, the reflow soldering device "RF-4 3 0 ”, manufactured by Nippon Pulse Giken Co., Ltd.), and the solder balls were melted, and the solder balls 6 were bonded to the plating 4 on the pads (FIG. 3). At this time, a part of the gold film 4 is dissolved in the solder ball, an alloy layer with copper or nickel as a base is formed, and the solder pole is fixed.
• the reflow soldering device “RF-4 3 0 ”, manufactured by Nippon Pulse Giken Co., Ltd.
• the reflow temperature and the reflow time were appropriately set in the range of 200 to 300 ° C. in consideration of the composition of the solder to be used, and the evaluation was performed.
• solder joint characteristics were evaluated by using a shear strength measuring device (in this study, “Bond Tester 400”, Digi Co., Ltd.), peeling the solder pole 6 from the pad (Fig. 4) and peeling it off. This was done by observing the surface conditions.
• a plating solution having the composition described in Example 1 in Table 3 was prepared in a 50-mL beaker, the pH was adjusted to 7.0, and the mixture was heated to 85 ° C in a water bath. After the substrate of Fig. 1 was plated with nickel under the conditions shown in Table 2 (Fig. 2 (b)), it was immersed in the prepared plating bath for 10 minutes to form a 0.06 micron thick gold film. . Pb solder balls were mounted on the 20 gold-plated pads, and after being fused with a reflow device at 230 ° C, 20 solder poles were peeled off with a shearing device. Observed.
• the plating solution was placed in an oven at 90 ° C, left for 80 hours, and then removed. However, no gold deposition was observed in the plating solution, and the plating bath had good thermal stability. Was.
• the pH was adjusted to 7.0 again, heated to 85 ° C in a hot water bath, and then the substrate shown in Fig. 1 was coated with nickel under the conditions shown in Table 2 (Fig. 2 (b)) was immersed for 10 minutes to obtain a plating film having a thickness of 0.06 ⁇ m.
• solder peeling mode was measured.95% of the pads in the solder were exposed and 5% of the pads with Ni interface exposed. It was just a mistake.
• a plating solution having the composition shown in Example 2 in Table 3 was prepared, and plated with a nickel-plated substrate (FIG. 2 (b)) in the same manner as in Example 1 to obtain a plating solution.
• a micron-thick gold-plated film was formed.
• the cut in the solder was as good as 100%.
• this plating solution was placed in an open at 90 ° C, gold deposition did not occur even after 80 hours and was stable.
• a plating solution having the composition described in Example 3 in Table 3 was prepared in a 50-mL beaker, the pH was adjusted to 5.0, and the mixture was heated to 85 ° C in a water bath. After pre-treating the substrate shown in Fig. 1 under the conditions shown in Table 1 (Fig. 2 (a)), it was immersed in the prepared plating bath for 10 minutes to form a coating having a thickness of 0.06 micron.
• Fig. 9 shows the results of analysis of the obtained gold-plated film in the depth direction using ESCA (QUANTUM2000, manufactured by ULVAC). No oxidation of the underlying copper was observed, and no carbon was detected in the plating film.
• the surface oxidation inhibitor suppresses the oxidation of the copper surface, but indicates that it is not incorporated into the plating film.
• a solder pole test was performed. Pb-free solder poles (Sn-Ag3.0-CuO.5) are mounted on the 2 2 pads that have been gold-plated, fused by a reflow device at 255 ° C, and then shared by a single device. Twenty solder balls were peeled off, and each peeled part was observed.
• the plating solution was placed in an oven at 90 ° C., left for 100 hours, and then taken out. However, no gold deposition was observed in the plating solution, and the thermal stability was good. .
• the pH was adjusted to 5.0 again, heated to 85 ° C in a hot water bath, and the substrate in Fig. 1 was pretreated under the conditions in Table 1 (Fig. a)) was immersed for 10 minutes to obtain a plating film having a thickness of 0.06 ⁇ m.
• the color of the gold-plated film was bright lemon yellow.
• solder peeling mode was measured. Only 5% of the pads had exposed Cu interface.
• the plating solution described in Example 3 was mixed at 50 OmL and placed in a 100 OmL beaker to perform a plating run-length test. A number of 5 cm square copper plates were prepared and plated under the conditions described in Example 3 to form a plated film of about 0.06 microns. The operation for the formation was repeated. The gold concentration in the plating solution was measured by ICP (SPS 3000, manufactured by Seiko Instruments Inc.) during Runjung, and the same amount of gold (1) gold cyanide was added every time the gold concentration decreased by 0.2 g ZL. The plating operation was repeated while replenishing, and the running was terminated when a total amount of 4.0 gZL of gold was consumed. The test took five days.
• the concentration of the surface oxidation inhibitor in the plating solution after the test was analyzed using a capillary electrophoresis device (CAP 13200, manufactured by Otsuka Electronics Co., Ltd.). The concentration was the same as before running. It was found that the surface oxidation inhibitor of the present invention did not decompose even under a long-time heating condition (85 ° C, between 53) and was not consumed during the plating reaction. -(Comparative Example 1)
• a plating solution having the composition shown in Comparative Example 1 in Table 3 was prepared and plated in the same manner as in Example 1 to form a plating film having a thickness of 0.07 ⁇ m. Twenty Pb solder balls were mounted on this gold-plated board in the same manner as in Example 1, and when the solder release mode was measured, the cut in the solder was only 10% and the remaining 90% was nickel The interface was exposed and the solder connection characteristics were unsatisfactory.
• a plating solution having the composition shown in Comparative Example 2 in Table 3 was prepared, and plated in the same manner as in Example 1 to form a plating film having a thickness of 0.07 ⁇ m. Twenty Pb solder balls were mounted on the gold-plated board in the same manner as in Example 1, and the solder peeling mode was measured. The cut in the solder was only 5%, and the remaining 95 ° / 0 was The nickel interface was exposed and the solder connection characteristics were unsatisfactory.
• FIG. 7 shows the Auger measurement result of Example 1
• FIG. 8 shows Comparative Example 1.
• Comparative Example 1 in which the surface oxidation inhibitor was not added, the Ni underlayer was severely oxidized. (Comparative Example 3).
• a plating solution having the composition shown in Comparative Example 3 in Table 3 was prepared, and a plating process was performed on a substrate treated in the same manner as in Example 3 to form a plating film having a thickness of 0.05 ⁇ m.
• 20 Pb-free solders (same composition as in Example 3) of this gold-plated board were measured for the ball peeling mode. %Met.
• gold deposition gold precipitation on the bottom of the beaker
• This plating solution had poor thermal stability due to the addition of the reducing agent ascorbic acid.
• a plating solution having the composition shown in Comparative Example 4 in Table 3 was prepared, and plating was performed in the same manner as in Example 3 to form a plating film having a thickness of 0.07 ⁇ m.
• Twenty Pb-free solder balls (same composition as in Example 3) were mounted on this gold-plated board in the same manner as in Example 3, and the solder peeling mode was measured. At 0%, the remaining 90. /. The Cu interface was exposed and had unsatisfactory solder connection characteristics.
• a plating solution having the composition shown in Comparative Example 5 in Table 3 was prepared and plated in the same manner as in Example 3.However, a black plating deposition layer was formed, and a lemon-yellow plating was performed. No film was obtained.
• the copper solubility of the chelating agent using phosphonic acid is low, and it is considered that copper was co-deposited with gold.
• the plating solution shown in Comparative Example 6 in Table 3 was prepared and plated in the same manner as in Example 3 to form a plating film having a thickness of 0.06 ⁇ m.
• the color of the gold-plated film was lemon yellow.
• Twenty Pb-free solder balls (same composition as in Example 3) were mounted on this gold-plated board in the same manner as in Example 3, and the solder peeling mode was measured. %, And the Cu interface was exposed in the remaining 80% of the pads, indicating unsatisfactory solder connection characteristics. Table 3

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