TW200426211A - Washing solution and washing method using the same - Google Patents

Abstract

This invention is to provide a washing liquid with excellent removal of impurities without corrosion of copper wiring used for semiconductor devices and the like or precipitation of the washing liquid components, particularly after chemical mechanical polishing (CMP) treatment using a slurry containing a highly adhesive anticorrosive agent such as benzotriazole without corrosion of copper wiring and capable of further removing benzotriazole together with impurity components under an alkaline condition. The washing liquid is composed of 0.001-60 wt.% of urea and/or ethyleneurea, 0.0001-10 wt.% of an alkaline component such as quaternary ammonium hydroxide and ammonia, 0.0001-10 wt.% of an organic acid such as citric acid, malic acid and tartaric acid or a salt thereof, 10 wt.% or less of hydrogen peroxide, if necessary, further a surfactant and water for the rest.

Description

200426211 (1) 发明. Description of the invention [Technical field to which the invention belongs] The present invention is a copper washing liquid, more specifically, a non-corrosive copper washing liquid for a semiconductor device can remove benzotriwa as a copper anti-clock bell oil [prior art] With the trend of miniaturization and high speed of information technology (LSI, ULSI, VLSI) in recent years, the multilayering of wiring has been carried out. The width of the wiring interval must be reduced, and the wiring interval must be reduced. We will try our best to change the current to low resistance. The technology of copper (CI) is related to copper wiring, and the mainstream tends to be buried wiring, using mechanical honing and the so-called C MP method (C hemica 1 M ech copper wiring material) is also figured out in the same way. According to CMP Method: Most metal particles and metal impurities are attached to the wafer. It is always washed with an alkaline solution. When metals other than copper are used, ammonia can generally be corroded. Ammonia cannot be used. Therefore, in order to reduce the corrosion rate of copper, it prevents corrosion. For example, the patent literature describes the use of copper compounds suitable for washing copper. The detergent of the present invention is a washing liquid for organic matter and the like. Developed from large-scale integrated circuits, high-density, high-integrated technology. Achieving the small size of the wiring and reducing the capacity of the wiring room, using tungsten and aluminum made of metal wiring materials. Into the elephant's eye method. Buried chemical by the elephant's eye method The rubbing effect is flattened by an ical polishing. After rubbing, the surface of the wafer must be cleaned due to the rubbing agent and the like. Because ammonia can be suppressed because of impurities. However, copper is easily a detergent. The proposal to add copper to ammonia water 1 reveals the addition of a succinic group-containing compound -5- (2) (2) 200426211 as a cleaning solution for the corrosion inhibitor. Further, Patent Document 2 proposes to use a compound formed by adding a morpholine compound and using water and / or a water-soluble organic solvent as a cleaning agent for the corrosion inhibitor. However, as described in the gazette, the fluorenyl group-containing compound has a particularly unpleasant odor, and its use as an anticorrosive agent has environmental and industrial problems. Aromatic compounds, such as benzotriazole, which are other corrosion inhibitors, are known to be highly harmful. Once attached to copper, benzotriazole has a problem that it is difficult to remove. In addition, a small amount of this corrosion inhibitor cannot suppress the corrosion of copper, and the corrosiveness and environmental problems of the ammonia-based cleaning solution that has been proposed have not been fully solved. In particular, it is known that once the benzotri-nine adheres to copper, it is difficult to remove. For example, Non-Patent Document 1 describes that benzotriazole forms a chelating agent with copper. The chelating agent formed by the residual copper and benzotriazole may cause a decrease in the yield of copper wiring semiconductors, which may have an adverse effect. As such, benzotriazole is not easily removed due to its strong adsorption to prevent the opposite side of copper oxidation. In addition, Non-Patent Document 1 describes the removal of benzotriazole under acidic conditions, and there is no description about the removal of benzotriazole under alkaline conditions. The cleaning solution for removing benzotriazole from copper films efficiently under alkaline conditions is unknown. . On the one hand, urea (derivatives) and hydroxy aromatics (Patent Document 3), which are proposed as essential components of copper corrosion inhibitors, are known as CMP honing slurry or photoresist film peeling agents. However, if these compounds do not contain a hydroxy aromatic compound, the anticorrosive effect is not obtained, and it is only suggested as a photoresist film peeling agent or a honing slurry, and it is not used as a cleaning solution. On the other hand, when washing with diluted ammonia water, a method using a carboxylic acid having an ability to form a chelating agent and its ammonium salt has been proposed (Patent Document 4). However, the method of -6- (3) 200426211 such a two-stage washing method is a little complicated and has problems in industrialization. In addition, a detergent (Patent Document 5) having a copolymer having a sulfonic acid group and the like has been proposed to disclose ammonium ions of the cations of the cleaning solution, including oxalic acid, citric acid, and the like as known detergent ingredients. However, in order to exert the performance as a cleaning agent, a copolymer is necessary, and a technique for triggering a cleaning function without adding this component is not suggested at all. [Non-Patent Document 1]

SCAS NEWS 200 1 -11, p7 [Patent Document 1] Japanese Patent Application Publication No. 2000-273663 (Scope of Patent Application) [Patent Document 2] Japanese Patent Application Publication No. 2 0 0 0-2 4 1 7 9 5 (Patent Scope of application) [Patent Document 3] Japanese Patent Laid-Open No. 2001-207107 [Patent Document 4]

Japanese Patent Laid-open No. 1] -3 3 0023 [Patent Document 5] Japanese Patent Laid-Open No. 2001-64681 [Content of the Invention] [Disclosure of the Invention] As explained above, 'so far, it contains ammonia and other alkaline cleaning solutions, and the corrosion of copper is Problem 'The use of an alkaline cleaning solution such as ammonia has a problem of insufficient cleaning effect. Therefore, it is required to use an alkaline solution such as ammonia to improve the cleaning effect, and there is no copper rot. -7- (4) (4) 200426211 A cleaning solution with corrosion problems. In view of the above-mentioned problems, the object of the present invention is to provide a cleaning solution that does not attack copper, has excellent impurity removal properties, does not precipitate cleaning solution components, and does not attack copper under alkaline conditions and remove organic substances such as benzotriazole. Net liquid. [Problem solving means] The present inventors and others thoroughly researched the results of the cleaning solution, and found that the cleaning solution made of water, @thio compounds, organic acids, and alkaline components can be used as a cleaning solution that does not invade the worm. It was also found that the cleaning solution containing hydrogen peroxide does not corrode copper, and particularly has an excellent effect on the removal of benzotriazole, and completed the present invention. That is, the present invention is a washing liquid made of water, urea and / or urea, organic acid and / or its salt and alkali components, and a washing liquid made of hydrogen peroxide and an interfacial agent. The present invention is described in detail below. The present invention is made of water, urea and / or ethylene urea, organic acid and / or its salt and alkali components. The cleaning solution of the present invention is sufficient to use urea and / or carbamide as corrosion inhibitors, and it is not necessary to add other corrosion inhibitors. However, the addition of other anti-satisfaction ingredients is not excluded as long as the function of the present invention is not hindered. Urea and ethylene urea used in the cleaning solution of the present invention can be used individually or in combination. These are easily commercially available. Urea and / or ethylene urea show good corrosion resistance and excellent natural decomposability. The organic acids used in the cleaning solution of the present invention are those containing a carboxylic acid or an expanded acid, and salts of these organic acids are also suitable for use. -8- (5) (5) 200426211 Specific examples of organic acids include carboxylic acids such as formic acid, acetic acid, oxalic acid, malonic acid, succinic acid, and osmic acid, citric acid, malic acid, tartaric acid, lactic acid, and glycolic acid. Hydroxycarboxylic acids such as sodium salicylic acid, sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, P · toluenesulfonic acid, 2,4 · toluene disulfonic acid, etc. Examples of such salts include sodium and potassium salts And other metal salts or ammonium salts. Among them, from the viewpoint of the ability to remove metal impurities and prevent precipitation of urea-based compounds, hydroxycarboxylic acids are preferred, and citric acid, malic acid, and tartaric acid are preferred. These organic acids also work to prevent the precipitation of urea compounds on the metal surface while removing metal impurities. When the urea compound is used alone, the crystals precipitated on the metal surface are difficult to remove only with water. The combination of the organic acids of the present invention can prevent the precipitation of crystals, especially ethylene urea has an effect. These organic acids and / or their salts can be used alone or in combination of two or more. These are generally available from commercially available products. The alkali component used in the cleaning solution of the present invention can be used arbitrarily if it is alkaline in an aqueous solution. However, since semiconductor applications are susceptible to metal impurities, those which do not contain alkali metals such as Li, Na, and K are preferred. Specific examples are tetramethylammonium hydroxide, trimethyl (ethylhydroxy) ammonium hydroxide (commonly known as choline), and fourth-order ammonium hydroxide salts, and ammonia. Among them, from the viewpoints of cleaning performance, suppression of the precipitation of urea and / or ethylene urea, and cost, ammonia and hydroxide of the fourth ammonium salt are particularly preferable. On the other hand, when amines such as methanolamine and urea compounds are used together, urea compounds are precipitated, which causes discoloration of copper. For the purpose of the present invention, hydrogen peroxide can be used as a strong film for removing benzotriazole and the like used as an anticorrosive agent, and it is difficult to remove organic substances. The hydrogen peroxide used in the cleaning solution of the present invention can be used by general marketers. (9) (6) (6) 200426211, and high-purity products for semiconductors are also easy to obtain. It is ideal to use this high-purity hydrogen peroxide. The cleaning solution of the present invention is generally an aqueous solution containing water, and a water-soluble organic solvent may be added for the purpose of improving the cleaning power. Aqueous organic solvents can be used as users of cleaning solutions. Specific examples include methanol, ethanol, η-propanol, i-propanol, η-butanol, i-butanol, sec · butanol, butanol, benzyl alcohol, ethylene glycol, propylene glycol, and polyethylene. Alcohols such as diols, 1-butoxy-2-propanol, amines such as N, N-dimethylmethylamine, N-methylpyrrolidone'dimethylimidazolindione Subcodes such as carboxide, and esters such as tetrahydrofuran, dioxane, and diglyme. The cleaning solution of the present invention may contain a surfactant in order to reduce surface tension and improve hydrophilicity. When a surfactant is contained, the contact between organic substances such as hydrophobic benzotriazole and the cleaning agent of the present invention is improved, and the removal performance of benzotriazole is improved. At the same time, the ability to remove particles from fine wiring of semiconductor devices and the like can be improved. Any surfactant can be used, and it is considered to be a semi-conductor for alkali metals and halogen ions, and a nonionic surfactant is preferably used. The non-ionic surfactants that can be used are not particularly limited, such as ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol propyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ether, propylene glycol propyl ether, and propylene glycol Butyl ether, diethylene glycol methyl ether, diethylene glycol ether, diethylene glycol propyl ether, diethylene glycol butyl ether, dipropylene glycol methyl ether, dipropylene glycol ether, dipropylene glycol propyl ether, dipropylene glycol butyl ether, etc. Ether alcohols. Among them, propylene glycol butyl ether and diethylene glycol butyl ether are preferable. -10- (7) (7) 200426211 The pH of the cleaning solution of the present invention is based on the viewpoint of suppressing copper rot, to obtain an excellent cleaning effect. It is preferably 7.1 to 12 and more preferably 7.5 to 11.5, and is particularly desirable. It is 8.0 to 1 1.0. The composition of the washing liquid of the present invention can be adjusted to the specified ρ 由 by the combination of urea and / or ethylene urea, organic acids and / or salts thereof, and basic components, hydrogen peroxide, and surfactants, etc. The mixing ratio varies depending on the compound used, from the content of urea and / or ethylene urea is 0.001 to 60% by weight, the content of organic acid and / or its salt is 0.0001 to 10% by weight, and the content of alkaline components The concentration is 0.0001 to 10% by weight, the content of hydrogen peroxide is 30% by weight or less, the ideal content when using hydrogen peroxide is 0.01 to 30% by weight, and when the surfactant is added, the content is 0.00 0 I ~ 10% by weight is ideal (the rest is water, and the entire amount is 100% by weight). Outside this range, it is not impossible to use it at the specified pH, which may lead to a decrease in particle removal performance, copper corrosion, precipitation of urea or ethylene urea crystallization. The cleaning solution of the present invention may be added with each component during washing, or may be used after mixing the components in advance. The cleaning liquid of the present invention can be used for cleaning copper wiring semiconductor devices. When the cleaning solution of the present invention is used, the absolute corrosiveness to copper wiring is small, and it is particularly suitable for cleaning after CMP. The washing means of the present invention can be used without particular limitation, and can be washed with running water, immersion washing, shaking washing, rotary washing, stirring stick washing, spray washing, ultrasonic washing, brush washing, etc. Known means. The temperature during washing is -11-(8) (8) 200426211. There is no particular limitation on the temperature. From the viewpoint of suppressing corrosion, particle removal, and operability, it is preferably 10 to 100 ° C. [Effects of the invention] The cleaning liquid of the present invention exhibits the ability to remove impurities with superior cleaning ability, and at the same time has no cleaning liquid precipitation components. It can be used as a cleaning liquid that does not corrode copper. It can also remove organic substances such as benzotriazole attached to the copper surface, which is extremely suitable for cleaning semiconductor devices. [Embodiment] The method of the present invention will be described by examples below, and the present invention is not limited to these examples. Examples 1 to 8 and Comparative Examples 1 to 4 (Particle Removability) The copper-plated wafers were immersed in ultrapure water with colloidal oxidized φ silicon with an average particle diameter of 120 nm, and then washed with ultrapure water adjusted to pH 6 with sulfuric acid net.

After drying, it is used as particles contaminated by oxidized sand particles. The wafer was immersed and washed at 50 ° C for 30 minutes with the cleaning solution shown in Table 1, and then washed with water and then dried. The surface of the table was observed by SEM (scanning electron microscopy), and the number of silicon oxide particles per unit area was viewed. SEM uses JSM T220A manufactured by Japan Electronics Co., Ltd. The particle removability is evaluated according to the following standards. 〇: Good removability -12- (9) (9) 200426211 △: Some residual X: Most residual (copper corrosive) The copper-plated wafer was immersed in the cleaning solution shown in Table 1 and immersed at 70 ° C After 1 hour, it was washed with water and dried. The film thickness of the copper film before and after immersion of this wafer was measured, and the dissolution rate was calculated from the amount of film thickness change to determine the anti-corrosion effect. The surface before and after immersion was observed with an AFM (atomic microscope) to observe the state of the surface of the copper film. The film thickness was measured using a sheet resistance measuring device manufactured by Mitsubishi Chemical Corporation of Japan, and a method of converting the film thickness from sheet resistance 値 was used. Copper corrosion is evaluated according to the following standards. 〇: Film thickness reduction less than 3 A / min. △: Film thickness reduction of 3 to 10 A / min. X: Film thickness reduction of more than 10 A / min. (Urea-based compound precipitation) Copper-plated wafers were washed as shown in Table 1. The solution was immersed in 70 ° C for 1 hour, and then washed with water and dried. The surface before and after immersion was observed with an AFM (atomic microscope) to observe the state of the surface of the copper film. As AFM, Nanopics manufactured by SEIKO INSTRUMENT Co., Ltd. was used. The results are shown in Table 1. (Removability of organic matter (benzotriazole)) Copper-plated wafer was immersed in an aqueous 2,3-benzotriazole aqueous solution at 0.6% by weight for 1 hour at room temperature, and washed with water to obtain adhered 1,2,3-benzotriazole. A copper wafer of azole. This crystal-13-200426211 (10) pieces are shown in Table 1 as the cleaning solution (the rest is water, and the entire cleaning solution is 100 weight ° / 〇, ultrasonically washed at room temperature) for 0 minutes, and then washed with water. 、 Dry. This copper wafer is analyzed by XPS (X-ray photoelectron spectroscopy), and the presence or absence of benzotrifluorene 1,2,3-benzotriazole (BTA) is checked. The amount of BTA before washing is compared. The standard price. The results are shown in Table 1. 〇: Residual amount 5% or less △: Residual amount 5 to 50% X: Residual amount 50% or more (11) 200426211 Table 1 Example composition (% by weight) pH urea compound precipitation Removable copper corrosive particles B but A Removable 1 EU (1.0) ΝΗ3 (0.0) Malic acid (〇.〇)) 9.7 None 〇〇1 2 EU (10) NH3 (0.01) Malic acid (〇.〇 υ 9.7 without 〇〇3 EU (1.0) NH3 (0.01) malic acid (〇.〇)) BP (10) 9.7 without 〇04 EU (1.0) NH3 (0.01) malic acid (o.oi) BP (1.0) 9.5 None 〇05 EU 〇.0) 3 (0.0)) Tartaric acid (〇.〇)) BP (1.0) 9.8 None 〇06 EU (10) NH3 (0.01) Malate (〇.〇)) BP (1.0 ) 9.8 None 0.07 EU (60) NH3 (0.01) Fruit acid (.00BP (1.0) 9.9 without 〇08 EU (1.0) TMAH (0.02) malate (〇.〇)) BP (1.0) 10.4 without 〇09 EU (1.0) NH3 (0.01) apple Acid (〇.〇)) BP (1.0) h2o20.0) 9.5 None 0.000] 0 EU (] .0) NH3 (0.01) Malic acid (〇.〇)) BP (10) h2o2 ( io) 9.4 None 〇〇〇〇Π EU () · 0) nh3 (o.oi) Malate (〇.〇)) BEE (IO) h2o2 (io) 9.5 No 〇〇〇12 EU (1.0) nh3 (oo) ) Malic acid (〇.〇)) BP (1.0) H2 2 0 2 0) 9.5 None 0.00 Comparative Example 1 EU (1.0) NH3 (0.01) 10.5 Fully precipitated Comparative Example 2 NH3 (0.01) 10.5 None Added X 〇 Comparative Example 3 3 (0.01) TGL (0.05)]] 0 No addition △ 〇 Comparative Example 4 EU (1.0) MEA (O. Ol) Malic acid (〇.〇)) BP (lO) 8.6 Fully precipitated X △ Comparative Example 5 NH3 (0.01) H2O2 (5.0) 9.2 No added X 〇〇 Comparative Example 6 EU (10) H2O2 (5.0) 7.2 Fully precipitated XX Comparative Example 7 EU (10) NH3 (0.01) 10.5 Fully precipitated. 〇X Comparative Example 8 nh3 (oo)) η2ο2 () · ο) 9.8 No added X 〇〇

Abbreviations EU: ethylene urea, U: urea, NH3: ammonia, TGL: thioglycerol, H202: hydrogen peroxide, BP: 1-butoxy-2-propanol, BEE: diethylene glycol butyl ether, BTA: 1,2,3-benzotriazole, TMAH: tetramethylammonium hydroxide, MEA ·· monomethanolamine-15-

Claims (1)

200426211 ⑴ Pickup, patent application scope 1 · A cleaning liquid, which is characterized by water, urea and / or ethylene urea, organic acid and / or its salt, and alkaline components. 2 · If the cleaning solution according to the scope of the patent application, the alkaline component is ammonia and / or level 4 ammonium hydroxide. 3. The cleaning liquid according to the item in the scope of the patent application, wherein the organic acid and its salt are more than one kind selected from oxalic acid, malonic acid, malic acid, citric acid, succinic acid, acid, tartaric acid, lactic acid, glycolic acid and the like Waiting for the hordes of salt. 4 · If the cleaning solution in the scope of application for item 丨, it contains more hydrogen peroxide. 5 · If the cleaning solution in the scope of patent application item 丨, it contains surfactants. 6 · The cleaning solution according to item 5 of the patent application, in which the surfactant is a non-ionic surfactant. 7. The cleaning solution according to item 5 of the application, wherein the surfactant is at least one selected from the group consisting of ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol propyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, Propylene glycol ether, propylene glycol propyl ether, propylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ether, diethylene glycol propyl ether, diethylene glycol butyl ether, dipropylene glycol methyl ether, dipropylene glycol ether, dipropylene glycol propylene Ether, Dipropylene glycol butyl ether group. 8. The cleaning solution according to item 1 of the scope of patent application, wherein P Η of the cleaning solution is 7 · 1 ~ 12. 9 · The cleaning solution according to any one of items 1 to 8 of the scope of the patent application, wherein the degree of urea and / or urea is 0.001 to 60% by weight, -16 · (2) (2) 200426211 The concentration of the organic acid is 0.01 to 10% by weight, the concentration of the basic component is 0.0001 to 10% by weight, the content of hydrogen peroxide is 30% by weight or less, and the surfactant is 10% by weight. /. The following ° 1 0. — A cleaning method, characterized in that the semiconductor device is cleaned by using a cleaning liquid according to any one of claims 1 to 8 of the scope of patent application. 1 1 · The cleaning method according to item 10 of the patent application scope, in which the semiconductor and m devices have copper wiring. -17- 4200426211 柒, (a) (b) The designated representative figure in this case is: None. The component representative symbol of this representative figure is simply explained: 4fflF 若 If the formula of this case: If there is no chemical formula, please disclose the chemistry that can best show the characteristics of the invention -4-