TW200925336A - Non-cyanogen type electrolytic gold plating bath for bump forming - Google Patents

Abstract

The invention discloses non-cyanogens-like electrolysis golden electroplate liquid used for forming protrusion, in which comprises 5 g/L to 150 g/L of conductive salt consisting of sulfurous acid gold alkali salt or sulfurous acid gold ammonium as the gold source, a crystal regulator, and potassium sulfite, 1 mg/L to 6 g/L of polyalkylene glycol with molecular weight 200 to 6000 and/or 0.1 mg to 1 g/L of ampholytic active agent, water-soluble amine and/or buffering agent; after electroplate gold plating on a patterned wafer by used of the gold electroplate liquid of the invention, protrusion with film hardness at 50 Hv to 90 Hv, and surface height difference less than 1.8 microns is formed after heat treatment at 200 degrees centigrade to 400 degrees centigrade for 5 min.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-cyanide electrolytic gold plating bath for bump formation of a semiconductor wafer. More specifically, it relates to a non-cyanide electrolytic gold plating bath which forms a bump having a flat surface and a desired hardness. The bumps formed are suitable for circuit bonding using an anisotropic conductive adhesive. Ο [Prior Art] The non-cyanide electrolytic gold plating bath generally contains a gold sulfite salt as a gold salt or a gold ammonium sulfite. It is known that the basic bath system is such a gold salt, a water-soluble amine as a stabilizer for the gold complex, a trace amount of Tl, Pb, or As compound as a crystal modifier of the electric shovel film, and further, sodium sulfite as an electrolyte or Sodium sulfate and buffers. (Japanese Patent Application No. 2005-286147 (Scope of Application for Patent Application)'--2005-145767 (Scope of Application for Patent)). © Gold bumps formed on a semiconductor wafer using a gold-plated bath have been widely used as electrodes for 1C and LSI in recent years. Figure 3 is a cross-sectional view of a conventional gold bump formed on a semiconductor wafer. When a gold bump is formed on a semiconductor wafer, first, a short-axis columnar aluminum (A1) electrode 2 is formed on the semiconductor wafer 1 by sputtering or the like. A compound wafer such as a sand wafer or GaAs is used on the semiconductor wafer 1. The surface of the wafer 1 is formed in advance with a circuit layer 1' including an integrated circuit. Next, the passivation film 3 is patterned. On the passivation film 3, the A1 electrode 2 is square -4-200925336 into an opening 3a. Thereafter, an under bump metal (UBM) layer 6 of a bump formed of a titanium-tungsten (TiW) sputter film 4 and a gold-sprayed film 5 is formed by sputtering. The UBM layer 6 is covered with the A1 electrode 2 exposed to the passivation film 3 and its opening portion 3a. The UBM layer 6 is attached to the photoresist film 8 for shielding. An opening 8a is formed in the photoresist film 8 above the A1 electrode 2. Next, in the opening 8a of the photoresist film 8, gold bumps 7 Ο are formed by electrolytic gold plating. Thereafter, the field of the photoresist film 8 and the gold sputtering film 5 (the region not covered by the gold bumps 7) and the Tiw sputtering film 4 are removed. As a result, the passivation film 3 is exposed, and a wafer on which the gold bumps 7 are formed is obtained. The semiconductor wafer (i.e., the semiconductor wafer) on which the gold bumps are formed is mounted in the subsequent step to mount the printed wiring substrate. At the time of mounting, the substrate electrode of the wiring pattern formed on the printed wiring board is connected to the gold bump formed on the semiconductor wafer. The connection is a flip chip bonding method in which wire bonding is performed using a metal wire and bonding the bump to the substrate 电极 electrode without using a metal wire. In recent years, in order to simplify the manufacturing steps of the semiconductor package and to perform the bonding reliably, a film-shaped anisotropic conductive adhesive is often used in the flip chip bonding method. The anisotropic conductive adhesive is one in which conductive particles are uniformly dispersed in an epoxy resin or the like. As the conductive particles, conductive particles having nickel or gold are sequentially coated on the surface of the particles formed of the acrylic resin. The shape and hardness of the bumps have a large influence on the bondability between the bumps and the substrate. The gold bumps are excellent in electrical conductivity and oxidation resistance, and are required to have a desired shape and hardness. -5- 200925336 In Fig. 3, 7' indicates the surface of the gold bump (the bonding surface with the substrate electrode). This surface 7' is a plane which is not parallel to the surface of the wafer 1, and is a convex shape which protrudes above the center. In addition to the above, there are cases where the surface of the bump is a concave shape or a shape in which the peripheral portion is cut. When the bumps of these shapes are bonded to the substrate, the conductive particles in the adhesive also fall into the concave or peripheral portion of the surface of the bump. Therefore, the conductive particles are not uniformly dispersed and disposed on the surface of the bump, but are biased in a part of the surface. As a result, the joint area is reduced by a small amount, and the bonding force between the gold bump and the counter substrate is not strong. This situation is caused by electrical defects due to wire breakage or poor joints after the installation step. Further, when the hardness of the bump is lower than that of the conductive particles, the conductive particles are not on the side of the bump. As a result, the conductive particles are not thermally bonded between the gold bumps and the counter substrate, and the bonding cannot be maintained. On the other hand, when the hardness of the bump is too high, only the conductive particles are crushed and cannot be joined, which causes disconnection or poor bonding, which causes electrical defects. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION As described above, the surface of the bump is uneven and convex or concave, and when the periphery of the bump is cut, the conductive particles of the anisotropic conductive adhesive cannot be It is evenly distributed on the surface of the bump and becomes a partially localized configuration. As a result, the bonding strength of the particles is reduced and the bonding strength is lowered. Therefore, when bonding is performed using an anisotropic conductive adhesive, as described above, the bonding surface must have a high smoothness. 200925336 Flat gold bumps. In the case where a bump is formed by a conventional electrolytic gold plating bath, the hardness of the gold bump cannot be made to have a desired hardness. As a result, the conductive particles passing through the anisotropic conductive adhesive do not cause electrical defects, but the bonding of the bumps to the substrate electrodes becomes difficult. Accordingly, it is an object of the present invention to provide a non-cyanide electrolytic gold plating bath for forming a bump which is capable of obtaining a gold bump having a hardness and a shape suitable for thermal compression bonding using an anisotropic conductive adhesive. Means for Solving the Problem The present inventors have made a discussion to solve the above problems. As a result, it was found that the hardness of the gold bumps can be controlled within a desired range by adjusting the addition amount of the ore bath having an alkanediol or an amphoteric surfactant having a predetermined molecular weight. Further, as a conductive salt, by using potassium sulfite and the above alkanediol or a two-sided active agent, it was found that a bump having a flat joint surface was obtained. ® The present invention for achieving the above object is as described below. [1] A non-cyanide electrolytic gold plating bath for forming a bump, which comprises a gold sulfite base salt or a gold ammonium sulfite, a crystal modifier, a potassium sulfite 5 to 150 g/L, and a molecular weight of 200 to 6000. Alkanediol 1 mg / L ~ 6 g / L and / or amphoteric surfactant 0 1 mg ~ 1 g / L and water-soluble amine and / or buffer. [2] The non-cyanide electrolytic gold plating bath for forming a bump according to [1], wherein the amphoteric surfactant is selected from the group consisting of 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, lauric acid Amidoxime hydroxysultaine, fatty acid decylamine 200925336 Ethyl ethylenediamine base electrolytic gold plating bath, or A s compound genus concentration. The heat treatment is performed by a patterned crystallizing gold bath, and the semiconductor wafer on the brush wiring substrate having a shape of 1.8 μm or less is connected: 50 to 90 Hv propyl betaine, and fatty acid sulfhydryl-N- One or two or more kinds of carboxyethyl-N-hydroxy salts. [3] The non-cyanide-based non-cyanide-forming method according to [1], wherein the crystal modifier is a T1 compound, a Pb compound, and a miscellaneous crystal modifier 0.1 to 100 mg/L is used as a gold [4] bump forming method. It is characterized in that the non-cyanide electroless gold plating for bump formation described in [1] is applied to the circle, and then the film hardness is 50 to 90 Hv at 200 to 400 ° C for 5 minutes or more, and the height difference of the surface is a bump. . [5] A connection structure in which a substrate electrode having a substrate wiring pattern formed on a substrate and a gold bump formed on the integrated circuit are used, and an anisotropic conductive adhesion connection structure is used, which is characterized by the aforementioned gold convex Block hard palate

EFFECTS OF THE INVENTION The salt is a non-cyanide electrolytic gold plating bath which does not use a surfactant or a preferable hardness such as poly or Ga/As. The non-cyanide electrolytic gold plating bath of the present invention contains sodium sulfite and contains a bisexual boundary. Alkanediol is an essential component. Thereby, when a bump is formed on the compound semiconductor wafer of the semiconductor wafer, an electrolytic gold plating layer > 4a block having a flat surface having no unevenness can be produced. In particular, the molecular weight and the added amount of the selected polyalkylene glycol can be controlled in the range of 50 to 90 Hv suitable for thermocompression bonding with the anisotropic conductive adhesive by blending with the sulfuric acid 200925336 potassium in the electroplating bath. The hardness of any 値 bump. The gold bumps formed by the electroplating bath of the present invention have a flat compressive surface and a desired hardness. Therefore, electrode bonding can be easily performed by an anisotropic conductive adhesive such as an anisotropic conductive film or an anisotropic conductive adhesive film used in the semiconductor manufacturing step. Moreover, the proportion of broken wires or poor joints is extremely small.金 The gold bump formed by using the plating bath of the present invention is not only expanded on the side surface of the bump which is in contact with the photoresist film on the bonding surface, so that a gold bump which is shaped like the opening of the photoresist film can be formed. Therefore, the side surface and the upper surface are gold bumps having a columnar shape or a polygonal column shape formed by a flat surface or a cylindrical gold bump which can form a uniform diameter. BEST MODE FOR CARRYING OUT THE INVENTION The electrolytic gold plating bath of the present invention is a non-cyanide gold plating bath, which is water-soluble as a stabilizer for gold sulfite or gold ammonium sulfite as a gold source. An electrolytic gold plating bath containing potassium sulfite, polyalkylene glycol and/or an amphoteric surfactant as a conductive salt in a bath composed of an amine and a trace amount of a crystal modifier and a buffer. The conductive salt system is substantially free of sodium sulfite. Hereinafter, each component of the electrolytic gold plating bath of the present invention will be described. (1) Gold sulfite alkali salt, gold ammonium sulfite (gold source) The gold sulfite salt used in the present invention is not limited to the use of the gold sulfite salt known from the publication -9-200925336. Examples of the gold sulfite base salt include sodium (I) sulfite and potassium (I) sulfite. These may be used alone or in combination of two or more. In the electrolytic gold plating bath of the present invention, the above-mentioned gold sulfite salt or gold ammonium sulfite is used as a gold source, and the blending amount thereof is generally 1 to 20 g/L, preferably 8 to 15 g/L. . When the blending amount of the gold sulfite alkali salt or the gold ammonium sulfite is less than lg/L, the thickness of the electrodeposited film is not uniform 〇. When it exceeds 20 g/L, there is no problem in the characteristics of the plating film, etc., but the production becomes high and becomes an economical burden. (2) Water-soluble amine (anti-setting agent) As the water-soluble amine, a diamine having 2 or more carbon atoms and preferably 2 to 6 carbon atoms can be used, and examples thereof include 1,2-diaminoethane and 1,2. - Diaminopropane, 1,6-diaminohexane, and the like. These systems can be used alone or in combination of two or more. The blending amount of the water-soluble amine is usually from 0.1 to 30 g/L, preferably from 1 to 12 g/L. When the blending amount of the water-soluble amine exceeds 30 g/L, the stability of the gold-salt salt increases, but on the other hand, the plating film is excessively densified and a problem of poor adhesion is caused. When the o.lg/L system limit voltage density is lowered, it may become a case of burnt plating. (3) T1 compound, Pb compound, and As compound (crystal modulating agent) The crystal adjusting agent used in the electrolytic gold plating bath of the present invention may, for example, be a T1 compound such as cesium formate, strontium malonate, barium sulfate or strontium nitrate. -10- 200925336 : Pb compound such as lead citrate, lead nitrate or lead alkane sulfonate; As compound such as arsenic trioxide. These T1 compounds, Pb compounds, and As compounds may be used alone or in combination of two or more. The blending amount of the crystal modifier may be appropriately set within a range not detracting from the object of the present invention, but the metal concentration is generally 0.1 to 1 mg/L, preferably 0.5 to 50 mg/L, particularly preferably. It is 3~25mg/L. When the blending amount of the crystal modifier is less than 0.1 mg/L, the plating adhesion, the plating bath stability, and the 耐久性 durability are deteriorated, and the constituent components of the electric ore bath are decomposed. When it exceeds 100 mg/L, there is a case where the plating adhesion is deteriorated and the appearance of the plating film is uneven. (4) Potassium sulfite (conductive salt) Potassium sulfite is used as the conductive salt in the electrolytic gold plating bath of the present invention. The blending amount of potassium sulfite in the electrolytic gold plating bath of the present invention can be suitably set within the range not impairing the object of the present invention, but it is preferably the following blending amount. The blending amount of potassium sulfite is usually 5 to 150 g/L, preferably 10 to 150 g/L, more preferably 50 to 100 g/L, particularly preferably 60 to 90 g/L. When the blending amount of potassium sulfite is less than 5 g/L, the expansion of the bump shape cannot be sufficiently suppressed to flatten the surface of the bump. Further, plating adhesion and liquid stability are deteriorated, and decomposition of the plating bath occurs. When it exceeds 150 g/L, there is a case where the limit current density is lowered and it becomes a burnt plating. In the electroplating bath of the present invention, as the conductive salt, a sodium salt substantially free of sodium sulfite, sodium sulfate or the like is contained. The sodium contained in the electroplating bath is limited to gold sodium sulfite from Jinyuan -11 - 200925336. (5) Buffering agent The buffering agent used in the present invention is not particularly limited as long as it is a user of a general electrolytic gold plating bath. For example, an organic acid such as a mineral acid salt such as a phosphate or a borate, a citrate salt, a citrate salt or an ethylenediaminetetraacetate salt (a polyvalent carboxylic acid of 2 to 5 or a hydroxycarboxylic acid) may be used alone. Two or more types can be used or used. The blending amount of the buffering agent in the non-cyanide electrolytic gold plating bath of the present invention is generally 1 to 30 g/L, preferably 2 to 15 g/L, particularly preferably 2 to 10 g/L. When the amount of the buffer is less than 1 g/L, the liquid stability deteriorates due to a decrease in pH, and there is a case where decomposition of the plating bath component occurs. When it exceeds 30 g/L, the limit current density is lowered to become a burnt shovel. (6) Polyalkylene glycol and amphoteric surfactant The polyalkylene glycol blended in the non-cyanide electrolytic gold plating bath of the present invention may, for example, be polyethylene glycol or polypropylene glycol. Examples of the amphoteric surfactant include beta-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, guanamine propyl hydroxythiobetaine, and fatty acid amidinopropyl betaine. An amphoteric surfactant; an aminocarboxylate-based amphoteric surfactant such as a fatty acid oxime ester-N-carboxyethyl-N-hydroxyethylethylenediamine base salt; an imidazoline derivative-based amphoteric surfactant. The blending amount of the polyalkylene glycol is from 1 mg/L to 6 g/L, preferably from 20 to 3,000 mg/L, particularly preferably from 1 to 10 mg/L. On the other hand, the blending amount of the surfactant -12-200925336 surfactant is generally 0.1 mg/L to lg/L, preferably 500 mg/L, particularly preferably 1 Torr to 300 mg/L. When the blending amount of the polyalkylene glycol and the amphoteric active agent is less than the above range, the hardness of the film after the heat treatment is less than 50 Hv, and further the shape of the surface of the bump cannot be made. When it exceeds the above range, the hardness of the bump after the heat treatment becomes 90 Hv or more, and the hardness suitable for joining cannot be obtained. The polyalkylene glycol and the amphoteric surfactant may also be used alone or in combination. When both are used, the blending amount of the two is suitably adjusted within the respective ranges for the purpose of blending. When the polyalkylene glycol is used, the film of the gold bump after the heat treatment is suitable for the bonding of the adhesive film for the anisotropic conductive film to 50 to 90 Hv, and the amount of use is 200 to 6000, preferably 400 to 2000, more preferably 400. ~ By. When the molecular weight exceeds 6,000, in order to make the hardness of the film after heat treatment | 〜90Hv, it is necessary to make the blending amount to be extremely low concentration of less than 1 mg/L. The concentration of the plating solution of the low concentration is difficult to manage. The hardness of the film formed by electroplating by adjusting the blending amount of the polyalkylene glycol having a molecular weight of 6,000 or less can be adjusted to be in the range of 50 to 90 Hv. The case of a low molecular weight polyalkylene glycol is increased by an amount, and in the case of a high molecular weight, by reducing the blending amount, a film hardness of 90 Hv can be obtained. In any of the molecular weights, a relatively high hardness of approximately 90 Hv can be obtained by increasing the hardness of the doped film. For example, when the film hardness after heat treatment is 70 Hv, the blending amount of the polyalkylene glycol having a quantity of 6000 or less is preferably 1 mg/L to 6 g/L, and it is preferably 20 to 300 Omg/L. Further, at this time, the two interface bumps are flat films, and the above hardness molecules are 1000 i 50 . For example, the blending amount of the active agent is preferably 10~3 OOmg/L, and the blending amount of the active agent is -10-200925336. Generally, by increasing the blending amount of the polyalkylene glycol or the amphoteric surfactant, the decrease in the hardness of the film due to the heat treatment is reduced. Further, in the case where potassium sulfite is blended without polyalkylene glycol or an amphoteric surfactant, the height difference of the surface of the bump is not sufficiently reduced. When only potassium sulfite, a polyalkylene glycol or an amphoteric surfactant is added, both the height difference of the surface of the bump and the hardness of the film can be desired. In the non-cyanide electrolytic gold plating bath of the present invention, other components such as a pH adjuster may be suitably used insofar as the object of the present invention is not impaired. Examples of the pH adjuster include sulfuric acid, sulfurous acid water, phosphoric acid, and the like; alkali potassium hydroxide, ammonia water, and the like. When the non-cyanide electrolytic gold plating bath of the present invention is used to form bumps on the semiconductor wafer via the electric shovel, the plating operation is preferably carried out in accordance with a usual method. For example, a Ti-W sputter film is used as the UBM layer, and a wafer on which an Au sputter film or the like is formed is masked with a photomask. Thereafter, the wafer is used as a substrate to be electroplated. Next, there is a method of dissolving the photomask in a solvent to remove it. After the photomask is removed, the portion not covered by the gold bumps of the UBM layer is removed by etching and heat treatment of the wafer is performed. In the case of the photomask, a novolak-based positive photoresist can be used. For example, LA-900, HA-900 (above, manufactured by Tokyo Yinghua Chemical Co., Ltd.) and the like can be cited. The temperature of the ore is generally 40 to 70 ° C, preferably 50 to 65 ° C. When the temperature of the plating bath is out of the range of 40 to 70 ° C, there is a case where the plating film is hard to be precipitated, or the plating bath is unstable, and decomposition of the plating bath component occurs. -14- 200925336 The set current density used in the electric ore is different depending on the composition of the plating solution, the temperature, etc., and it is difficult to determine it by one meaning. The gold concentration is generally 8 to 15 g/dm2 or less, preferably 〇2 to 1.2 A/dm2 under the condition of the electric ore bath temperature of TC. When the current density is out of the above range, there is In the case where the workability is poor, or the appearance of the plating film or the characteristics of the electric shovel film is abnormal, or the plating bath becomes unstable and the decomposition of the plating bath component is caused. ® As the non-cyanide electrolytic gold plating bath of the present invention The pH is generally 7.0 or more, preferably 7.2 to 1 〇. 〇. When the pH of the non-cyanide electrolytic gold plating bath is less than 7.0, there is a case where the plating bath becomes unstable and decomposes. On the other hand, the pH exceeds 10.0, the photomask is dissolved and the desired gold bumps and the like cannot be formed. The heat treatment temperature of the gold bumps is 200 to 400 ° C, preferably 200 to 300 ° C. The heat treatment time is 5 minutes or longer. It is preferably 30 to 60 minutes. The heat treatment is carried out by using a precision thermostat (Fine Oven) or the like which can hold the inside of the chamber for a certain period of time at a set temperature. The non-cyanide electrolytic gold plating bath of the present invention is used. Supplementary management of its constituent gold source and electroplating bath The other components can be used for 2 turns (consumption of the amount of gold in all electroplating baths as 1 turn) in the electroplating bath. The non-cyanide electrowinning gold bath of the present invention can be metallized to be electrically conductive. If the material is not selected, the photomask is made of a novolac-based positive photoresist, which is particularly suitable for forming bumps on patterned wafers or on compound wafers such as Ga/As wafers. Fig. 1 is a cross-sectional view showing an example of forming a gold-15-200925336 bump on a semiconductor wafer using the gold plating bath of the present invention. In Fig. 1, 1 is a semiconductor wafer, and is formed to contain The circuit layer of the integrated circuit on the semiconductor wafer, 2 is an A1 electrode, 3 is a passivation film, 3a is an opening of a passivation film, 4 is a TiW溺 plating film, 5 is a gold sputtering film, and 6 is a TiW sputtering film. 4, the UBM layer formed by the gold splash film 5, 7 is the gold bump '7' is the surface of the gold bump, 8 is the opening of the photoresist film, and 8a is the opening of the photoresist film. Gold bump The surface 7, which is formed flat, contacts the height difference 中央 of the central portion 7'a and the peripheral end portions 7 and b of the photoresist film (the distance from the wafer 1) It is preferably within 1·8 μm, preferably within 1·7 μm, preferably within 1·6 μm, and preferably within 1.5 μm. Fig. 2 is a semiconductor wafer in which the gold bumps shown in Fig. 1 are formed In the same manner as in the first embodiment, the same reference numerals will be given to the same portions as those in the first embodiment, and the description thereof will be omitted. The printed wiring board 1 has a substrate wiring formed of a conductive material such as copper. The pattern type 12 is formed on the substrate wiring pattern 1 2 with the substrate electrode 14 formed of a conductive material such as gold. On the other side, a semiconductor bump 16 mounted on the substrate 1 in parallel with the printed wiring board 1 is formed with gold bumps 7 opposed to the substrate electrodes 14. The substrate electrode 14 and the gold bump 7 are bonded by the anisotropic conductive adhesive 20. The hard substrate 11 and the semiconductor wafer 1 are sealed by a sealing material I8. The material of the hard substrate 1 1 is not particularly limited as long as it is used for a hard printed wiring board, and examples thereof include glass reinforced epoxy resin and ceramics. As the sealing material 18, a known resin used for sealing a semiconductor wafer can be generally used. The formation of the substrate wiring pattern 10, -16-200925336 toward the hard substrate 11 is performed by vapor deposition, electroplating, etching of a metal thin film, application of a conductive coating, or the like. The method of attaching the semiconductor wafer 16 to the printed wiring board 1 is performed as follows. First, the position of the gold bumps 7 is placed above the substrate electrodes 14, and the position of the semiconductor wafer 16 is determined, and the semiconductor wafer 16 is placed on the printed wiring board 10 via the film-shaped anisotropic conductive adhesive 20. Next, the gold bumps 7 〇 and the substrate electrode 14 are thermally pressed via the anisotropic conductive adhesive 20. The gold bumps 7 formed on the electrodes of the integrated circuits in the circuit layer 1' are attached to the substrate electrodes 14 formed on the substrate wiring pattern 12 by mounting the semiconductor wafers 16 facing the printed wiring board 1'. The anisotropic conductive adhesive 20 is joined. [Embodiment] Example A non-cyanide electrolytic gold plating bath was prepared by mixing as shown in Tables 1 to 4. The unit of the blending concentration of each raw material is g/L unless otherwise specified. However, 'Na3Au(S03)2 and ammonium ammonium sulfite indicate the concentration for the amount of Au. As the object to be plated, a ruthenium wafer having a bump opening portion (a texture cross-section composition of gold sputter film / TiW/SiO 2 ) patterned with a novolac-based positive resist was used. The plated material was immersed in 1 L of the prepared non-cyanide electrolytic gold plating bath, and a gold plating film having a film thickness of 15 μm was formed by applying electricity. Further, the current efficiency of the non-cyanide electrolytic gold plating bath is generally 1 〇 0% under normal plating operation conditions. After forming a film having a predetermined film thickness, the photomask is removed, and the shape of the bumps of the shape -17-200925336, the bath stability, the appearance of the plating film, the film hardness (after heat treatment and heat treatment at 300 ° C for 30 minutes), The etchability of the iodine-based etchant by the au sputtering film was evaluated by the following method and standard. The combined results are shown in Tables 1 to 4. [The height difference of the surface of the bump (μιη);] As shown in Fig. 1, the phenolic varnish-based positive photoresist is used on the wafer, and the long side is 80 to 20 μm and the short side is 80 to 20 μm. The pattern of the rectangular opening is formed. After electroplating using an electrolytic gold plating bath, a novolac-based positive photoresist was dissolved in methyl ethyl ketone as a solvent. Using the laser microscope VK_9710 manufactured by KEYENCE, the obtained bump was used to measure the difference between the highest point on the upper surface of the bump and the lowest point on the upper side as the height difference and to make a smoothness index. Further, the height difference obtained in general for bump plating applications is 3 μm or less, preferably 2 μm or less, and more preferably 1.5 μm or less. 〔 [Bath stability] The appearance of the plating bath after plating on the object to be plated was observed and evaluated on the basis of the following criteria. Decomposition: decomposition of components in the electroplating bath. X: The precipitation of gold in the electric ore bath was observed to the extent that it was judged by the naked eye. △: Confirm a little gold spill in the plating bath. The degree of observation can be filtered by a 〇2μιη membrane filter. 〇: No precipitation of gold in the electric mine bath was observed. -18- 200925336 [Appearance of plating film] The appearance of the surface film of the bump formed on the mineral was observed and evaluated on the following basis. X: The color tone is red and the dendrites are precipitated, and unevenness is confirmed, and scorching occurs. △: There was no abnormal precipitation, and it was a glossy appearance. 〇: The hue is lemon yellow and has no ~ semi-gloss uniform appearance. 〔 [Film hardness (Vickers hardness; Hv)] Using a specific bump portion formed on the ammonium material, the film hardness (after heat treatment and heat treatment at 300 ° C for 30 minutes) is performed on a Vickers hardness tester. Determination. The characteristics obtained for the bumps for medium hardness use are about 70 Hv after annealing. Further, the measurement conditions were such that the indenter was maintained at a load of 25 gf for 1 sec. © [Etching property of iodine-based etchant by Au plating method] The object to be plated was immersed in an iodine-based etchant which was sufficiently stirred at room temperature for 90 seconds, washed in an alcohol-based rinsing liquid, and then sprayed with ethanol to dry with a hair dryer. Thereafter, the surface state of the full bump formed on the object to be plated was observed with a metal microscope at a magnification of 50 to 200 times, and evaluated based on the following criteria. X: It was observed that the surface of the bumps of 50% or more was uneven. △: It was observed that only a part of the area of the bump had a surface. 〇: No unevenness in the surface of the full bump on the object to be plated was observed. -19- 200925336 [Total Evaluation] The above evaluation results are evaluated on the basis of the following evaluation criteria. X: The above evaluation results of the formed gold plating film (gold bump) and the non-cyanide electrolytic gold plating bath after the plating treatment included a bad result △: Regarding the formed gold film (gold bump) In the above evaluation results of the non-gas-based electrolytic gold plating bath after the shovel treatment, the results of the partial improvement include some unfavorable results. 〇 〇: The results of the above evaluations of the formed gold plating film (gold bump) and the non-cyanide electrolytic gold plating bath after the plating treatment were all good results. ❹ -20- 200925336

m _ 1 2 3 4 5 6 7 8 9 10 Blending concentration (g/L) Na3Au(S03)2 as Au 10 10 10 10 10 12 12 12 12 12 K2S〇3 75 75 75 75 75 75 75 75 75 75 N32S03 1,2-diaminoethylamine 4 4 4 4 4 4 4 4 4 4 Phosphate 5 5 5 5 5 Disodium edetate 10 10 10 10 10 Tl (mg/L) 15 15 15 15 15 15 15 15 15 15 Polyethylene glycol A (mg/L) 5000 — — — 2000 — — — — Polyethylene glycol B (mg/L) — 300 — — — — 100 — — — Polyethylene glycol C ( Mg/L) — — 20 — — — — 5 — — Sexual interfacial activity A (mg/L) — — — 700 — — — — 150 — Sexual interfacial activity B (mg/L) — — — — 300 — — — — 50 pH 7.8 7.8 7.8 7.8 7.8 7.8 7.8 7.8 7.8 7.8 Plating conditions Plating temperature (..) 60 60 60 60 60 60 60 60 60 60 Current density (A/dm2) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Film thickness (― 15 15 15 15 15 15 15 15 15 15 Bump shape height difference (μιη) 1.43 1.47 1.39 1.52 1.47 1.19 1.16 1.01 1.47 1.36 Bath stability 〇〇〇〇〇〇〇〇〇〇 Coating appearance 〇〇〇〇〇〇〇〇〇〇 etchability 〇〇〇〇〇〇〇〇〇〇 film hardness without heat treatment (Ην) 95 93 92 92 101 103 105 101 99 107 After heat treatment at 300 ° C (Ην) 67 69 76 73 64 62 70 75 68 60 Aggregate assessment〇〇〇〇〇〇〇〇〇〇•21 - 200925336 Table 2

Real S _ 11 12 13 14 15 16 17 18 19 20 Blending concentration (g/L) Na3Au(S03)2 as Au 10 10 10 10 10 12 12 12 12 12 Gold ammonium sulfite K2S〇3 75 75 75 75 75 75 75 75 75 75 Na2S03 1,2-diaminoethylamine 4 4 4 4 4 Disodium edetate 10 10 10 10 10 Tl(mg/L) 15 15 15 15 15 10 10 10 10 10 Glycol A (mg/L) 3000 — — — 500 — — — — Polyethylene glycol B (mg/L) — 200 — — — — 20 — — — Polyethylene glycol C (mg / L) 10 1 Amphoteric interface activity A (mg/L) — — — 400 — — — — 30 — Amphiphilic interfacial activity B (mg/L) — — — — 100 — — — — 10 PH 7.8 7.8 7.8 7.8 7.8 7.8 7.8 7.8 7.8 7.8 Electro-minening conditions electroplating ΓΟ 60 60 60 60 60 60 60 60 60 60 Current density (A/dm2) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Film thickness (μιη) 15 15 15 15 15 15 15 15 15 15 Bump Shape height difference (μιη) 1.36 1.34 1.23 1.50 1.45 1.34 1.27 1.21 1.53 1.56 Bath stability The appearance of the furnace film 〇 〇 〇 〇 〇 〇 〇 〇 蚀刻 蚀刻 蚀刻 蚀刻 〇 〇 〇 〇 〇 〇 〇 皮 Film hardness Unheated (Ην) 96 93 97 94 100 95 99 92 89 94 300. . After heat treatment (Ην) 65 69 72 75 69 77 79 78 75 70 Total evaluation 〇 〇 〇 〇 〇 〇 〇 〇 〇 -22 -22- 200925336

Table 3 Example 21 22 23 24 25 26 27 Blending concentration (g/L) Na3Au(S03)2 as Au 10 10 10 10 10 - — Gold ammonium sulfite — — — 1 — 1 20 K2S〇3 5 150 75 75 75 75 75 Na2S03 — I — — — — — 1,2-Diaminoethylamine 4 4 4 4 4 — —1,6-Diaminohexane——— — — 0.1 30 Phosphoric acid 5 5 5 5 5 — — Disodium edetate — — — — — 10 10 Tl(mg/L) 15 15 15 15 15 15 15 Polyethylene glycol A (mg/L) 5000 5000 — — 500 500 — Polyethylene glycol B(mg/L) — 200 — — — — 1000 Polyethylene glycol C (mg/L) Amphoteric interface activity A (mg/L) — — 5 900 — — — Sexual interface activity B (mg/L) — — — — 10 — — pH 7.8 7.8 7.8 7.8 7.8 7.8 7.8 Plating conditions Electrowinning temperature rc) 60 60 60 60 60 60 60 Current density (A/dm2) 0.3 0.5 0.5 0.5 0.5 0.2 0.8 Film thickness (μιη) 15 15 15 15 15 15 15 Bump shape height difference (μπι) 1.62 1.56 1.44 1.56 1.34 1.53 1.33 Bath stability 〇〇〇〇〇〇〇 plating appearance Δ 〇〇Δ 〇Δ 〇 etch 〇 〇 〇 〇 〇 〇 皮 Film hardness Unheated (Ην) 96 90 104 91 95 90 101 300. (3 After heat treatment (Ην) 68 71 51 86 75 70 61 Total evaluation Δ 〇 〇 Δ 〇 Δ 〇 -23- 200925336 Table 4

Comparative Example 1 2 3 4 5 6 7 8 9 10 Blending Concentration (g/L) Na3Au(S03)2 as Au 10 10 10 10 10 10 10 12 12 12 K2S〇3 75 Na2S03 — 60 60 60 60 60 60 60 60 60 1,2-diaminoethylamine 4 4 4 4 4 4 4 4 4 4 Phosphoric acid 5 5 5 5 5 5 5 —-disodium monoethylenediaminetetraacetate 10 10 10 Tl(mg/L) 15 15 15 15 15 15 15 15 15 15 Polyethylene glycol A (mg/L) — — 5000 — — — — 2000 — — Polyethylene glycol B (mg/L) — — — 300 — — — — 100 One poly Glycol C (mg/L) — — — — 20 — — — — 5 Sexual interfacial activity A (mg/L) — — — — — 700 — — — — Sexual interfacial activity B (mg/L) — — — — — — 300 — — — — — — — — — — — — — — — — — — — — — — — — 0.5 0.5 Film thickness (μιη) 15 15 15 15 15 15 15 15 15 15 Bump shape height difference (μιη) 1.83 3.11 2.48 2.48 2.20 2.63 2.58 2.04 1.98 1.85 Bath stability 〇〇〇〇〇〇〇 〇〇〇Electric acid film appearance 〇〇〇〇〇〇〇〇〇〇 etchability Δ Δ 〇〇〇〇〇〇〇〇 film hardness not heat treated (Hv) 106 105 91 89 90 87 99 100 102 101 300. Heat treatment After (Hv) 45 43 66 71 78 70 65 65 71 76 Total evaluation Δ XXXXXXX △ Δ -24- 200925336 Table 5

Comparative Example 11 12 13 14 Blending concentration (g/L) Na3Au(S03)2 as Au 12 12 10 10 k2so3 — — 75 75 N32SO3 60 60 — 1,2-diaminoethylamine 4 4 4 -phosphoric acid — — 5 — Disodium edetate 10 10 — 10 Tl (mg/L) 15 15 15 15 Polyethylene glycol A (mg/L) — — 10000 Polyethylene glycol B (mg/L) — — — — Polyethylene glycol C (mg/L) — — — — Amphiphilic interfacial activity A (mg/L) 150 — — 2000 Sexual interfacial activity B (mg/L) — 50 — — pH 7.8 7.8 7.8 7.8 Electron ore conditions Plating temperature CC) 60 60 60 60 Current density (A/dm2) 0.5 0.5 0.5 0.5 Film thickness (4) 15 15 15 15 Bump shape height difference (μπι) 2.39 2.22 1.56 1.59 Bath stability 〇〇〇〇Electric acid film appearance〇 〇Δ X Etching film hardness not heat treated (Ην) 97 105 98 102 300°C after heat treatment (Ην) 65 66 96 100 Total evaluation XXXX

Polyethylene glycol A: Average molecular weight 400 Polyethylene glycol B: Average molecular weight 1000 Polyethylene glycol C: Average molecular weight 6000 Amphoteric interface activity Λ: Made by Nippon Oil & Fat Co., Ltd., NISSAN ANON BDL (carboxybetaine) Activity B: manufactured by Kao Co., Ltd., AMPHITOL20YB (carboxybetaine system) -25- 200925336 By comparison of the comparative examples and comparative examples, it is clear that the following is the 〇(1) potassium sulfite system to make the surface of the bump The effect of reducing the height difference is the principle. The height difference of Examples 1 to 20 containing potassium sulfite was 1.01 to 1.56, and the height of the bumps was compared with that of Comparative Examples 2 to 12 containing sodium sulfite, which was 1. 8 5 to 3.11. The height difference is obviously small. 〇 (2) The polyalkylene glycol and the amphoteric surfactant are based on the effect of reducing the hardness of the film after heat treatment at 300 °C. Examples 1 to 20 containing a polyalkylene glycol or an amphoteric surfactant are suitable for film hardness after heat treatment at 300 ° C (50 to 90 Hv). On the other hand, the hardness of Comparative Examples 1 and 2 which did not contain a polyalkylene glycol and an amphoteric surfactant was as low as 45 Hv and 43 Hv. (3) However, the addition of only potassium sulfite is not sufficient to reduce the height difference of the surface of the bump. Although Comparative Example 1 was added with the same amount of potassium sulfite as in Examples 1 to 20, the height difference was still large (1.83). By adding a polyalkylene glycol or an amphoteric surfactant to potassium sulfite, the difference in height was changed to 1.56 or less (Examples 1 to 20). BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an example of a gold bump formed by using the gold plating bath of the present invention. Fig. 2 is a cross-sectional view showing an example of a state in which a semiconductor wafer having gold bumps shown in Fig. 1 is mounted on a printed wiring board. -26- 200925336 Figure 3 shows a cross-sectional view of a gold bump formed using a conventional gold plating bath. [Main component symbol description] 1 : Semiconductor wafer 1 ' : Circuit layer 2 : A1 electrode 〇 3 : Passivation film 3 a : Passivation film opening 4 : TiW sputtering film 5 : Gold sputtering film 6 : UBM layer 7 : Gold Bump 7': surface 8 of gold bump: photoresist film © 8a: opening portion 1 of photoresist film 〇: printed wiring substrate Η : hard substrate 1 2 : substrate wiring pattern 1 4 : substrate electrode 1 6 : semiconductor Wafer 18: Sealing Material 20: Anisotropic Conductive Adhesive-27-

Claims (1)

200925336 X. Patent application scope 1. A non-cyanide electrolytic gold bath for forming a bump, which is characterized by containing gold alkali sulfite or gold ammonium sulfite, crystal modifier, potassium sulfite 5 to 150 g/L, molecular weight It is made up of 200~6000 polyalkylene glycol 1mg/L~6g / L and / or amphoteric surfactant 〇. 1 mg~1 g / L with water-soluble amine and / or buffer. 2. The non-cyanide electrolytic ruthenium gold plating bath for bump forming according to the first aspect of the patent application, wherein the amphoteric surfactant is selected from the group consisting of 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, One or more of melamine propyl hydroxy sulfobetaine, a fatty acid guanamine propyl betaine, and a fatty acid sulfhydryl-N-carboxyethyl-N-hydroxyethylethylenediamine base salt. 3 · A non-cyanide electrolytic gold plating bath for bump forming according to item 1 of the patent application, wherein the crystal modifier is a T1 compound, a Pb compound, or an As compound, and a crystal modifier is blended. 0~1 0 0 mg / L as a metal concentration 〇Ο 4 - a bump forming method, characterized in that after electroplating is performed on a patterned wafer using a non-cyanide electrolytic gold plating bath for bump forming in the first application of the patent scope, The heat treatment is carried out at 200 to 400 ° C for 5 minutes or more to form a bump having a film hardness of 50 to 90 Hv and a surface height difference of 1.8 μm or less. 5. A connection structure for a substrate electrode having a substrate wiring pattern formed on a printed wiring substrate and a gold bump formed on an integrated circuit formed on the semiconductor wafer, using an anisotropic conductive adhesive The connection structure of the connection is characterized in that the hardness of the gold bump is 50 to 90 Ην. -28-