JP2006058675A - Exfoliating liquid for multistage treatment and method for exfoliating etching residual substance using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exfoliating liquid for a multistage treatment, with which an exfoliating treatment of etching residual substances formed in a wiring structure forming process of a display panel of a semiconductor multilayered wiring structure, a liquid crystal panel, or the like, is safely carried out without lowering the exfoliating performance in comparison with a conventional exfoliating liquid. <P>SOLUTION: When the etching residual substances are exfoliated, as the exfoliating liquid, at least two liquids of an exfoliating agent having a dissolving property to titanium and a titanium compound and an exfoliating agent containing at least a quaternary ammonium hydroxide are used in a multistage manner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention performs a peeling process on an etching residue formed in a wiring structure forming process of a display panel such as a semiconductor multilayer wiring structure or a liquid crystal panel safely and without lowering the peeling performance as compared with a conventional peeling liquid. The present invention relates to a stripping solution for multistage treatment that can be performed and a method for stripping etching residues using the stripping solution.

  As is well known, a basic wiring structure in a semiconductor integrated circuit includes a lower wiring layer formed directly or indirectly on a semiconductor substrate, and an upper wiring layer formed on the lower wiring layer via an interlayer insulating layer. Are connected by via wirings formed so as to penetrate the interlayer insulating layer. A multilayer wiring structure of a semiconductor integrated circuit is formed by multiplying the wiring structure into multiple layers.

This wiring structure is realized by repeatedly forming layers such as a conductor layer and an interlayer insulating layer stacked on a semiconductor substrate and patterning them by etching.
As is well known, the etching process mainly employs a dry etching technique. When the wiring layer and the insulating layer are processed by dry etching, the wiring layer and the insulating layer material shaved by the dry etching are formed in a state in which they are subjected to alterations such as components or oxidation as they are. It adheres to the sidewall and bottom of the etching space. When the etching space is a via hole, the etching process is stopped when the surface of the wiring layer is exposed. However, some of the surface of the wiring layer is inevitably etched. The etched wiring layer material also adheres to the sidewalls and bottom of the etching space in the same component or compounded state. In current semiconductor substrates and the like, a barrier metal is formed between the wiring layer and the insulating layer, and etching residues are roughly classified into residues resulting from the insulating layer and the wiring layer and residues resulting from the barrier metal. These residues remain at the same time in the etching space, although there are some amounts depending on the etching conditions at that time. In addition, after forming the etching space, the patterned resist layer remains on the surface of the insulating layer as a mask for performing etching, so this resist layer is removed by an ashing process. The altered film (residue) may be generated in the etching space.

  If the device formation process is carried out with the etching residue remaining as it is, the physical characteristics and chemical characteristics including the electrical characteristics of the formed via wiring are greatly impaired. Therefore, in the wiring formation process, after the etching space is formed, a step of stripping and removing the residue in the etching space using a stripping solution is essential.

  As a conventional stripping solution, a stripping solution mainly composed of hydroxylamine has been used (Patent Document 1). This stripping solution containing hydroxylamine as a main component has a good stripping property for both the etching residue deposits derived from the wiring layer and the insulating layer, and the residues derived from the barrier metal. In addition, since the invasiveness to the wiring layer is low and it is difficult to damage both layers, it has been actively used as a stripping solution.

  A stripping solution having such a universal stripping property has not been developed at present except for the hydroxylamine stripping solution, and is excellent in stripping of etching residues derived from wiring layers and insulating layers. Only a stripping solution specialized in the stripping property of one kind of residue is provided such that the stripping property of the etching residue derived from metal is poor or has reverse characteristics.

  Aluminum is mainly used for the wiring layer, but when aluminum is used as the wiring layer material, a titanium-based compound film such as titanium nitride is formed on the aluminum wiring layer. In the wiring structure using the aluminum wiring layer, when the via is formed by etching, the titanium-based compound film is also etched, so that it adheres as a residue. This titanium residue cannot be easily peeled off with a stripper other than the hydroxylamine stripper as described above. On the other hand, the peeling liquid specialized in peeling of titanium is provided (patent document 2).

  As described above, as a stripping solution capable of stripping off residues formed on the side wall and bottom of the etching space at a time, only a stripping solution containing hydroxylamine as a main component has been provided so far.

  The method of forming an etching space for forming a wiring layer in the semiconductor multilayer wiring structure is also performed in forming a wiring structure in a display panel such as a liquid crystal panel. Therefore, also in the formation of other wiring structures such as liquid crystal panels, there is a problem that etching residues are formed in the etching space in the manufacturing process and must be efficiently removed. ing.

JP-A-9-299500 JP 2004-71585 A

  However, in the stripping cleaning process using the stripping solution containing hydroxylamine as a main component, hydroxylamine itself is relatively rich in reactivity, so it is subject to severe restrictions in terms of storage temperature control and safety. It is difficult to handle.

  On the other hand, we examined whether the residue could be peeled off with other stripping liquids such as titanium stripping liquid and stripping liquid not containing hydroxylamine, but in the stripping process where stripping should always be possible, the result of peeling residue became. As a result of searching for the cause, the following findings were obtained.

  In general, a large number of vias connecting an upper wiring layer and a lower wiring layer formed through an insulating space, for example, an insulating layer, are formed on one wiring board. In this large number of spaces to be etched, the laminated structure of the residue deposits formed inside differs depending on the formation position such as whether the formation position is the center or the end of the substrate. That is, it has been found that the residue due to the etching treatment is mostly the residue due to the wiring layer and the insulating layer, and the residue due to the barrier metal layer is further generated. Since there is a variation in the layered structure of residues in the space to be etched on a single wiring board, a single sheet must be used unless it is a stripping solution with universal stripping properties such as hydroxylamine stripping solution. It has been found that it is difficult to sufficiently clean the etching space in the substrate.

  The present invention has been made in view of the above circumstances, and the problem is that the etching residue formed in the wiring formation process such as a semiconductor multilayer wiring structure or a liquid crystal panel can be removed safely and compared to the conventional products. An object of the present invention is to provide a stripping solution for multistage treatment which can be removed without degrading performance and a method for stripping etching residues using the stripping solution.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, experiments, and studies, and have obtained the following knowledge.

  Although it is possible to strip and remove the entire residue using a stripper containing hydroxylamine as the main component, hydroxylamine itself is relatively rich in reactivity. However, it is difficult to handle because of severe restrictions. However, any stripping solution that is soluble in titanium and titanium compounds can be stripped of titanium and titanium compounds. Similarly, a stripping solution containing quaternary ammonium hydroxide as the main component can be used. For example, it is possible to remove the silica-based residue or the aluminum-based residue. Moreover, it is much safer and easier to handle than the case of using a stripper containing hydroxylamine as a main component.

  Therefore, the time for the titanium residue to sufficiently peel off the stripping solution for multi-stage treatment composed of at least two kinds of stripping solutions, specifically, the stripping solution having solubility in titanium and titanium compound as one stripping solution. If the substrate is allowed to act on the substrate, and then the other stripping solution containing quaternary ammonium hydroxide as the main component is allowed to act on the substrate, the residue in all the etched spaces on the single substrate Can be sufficiently peeled and removed.

  The present invention has been made based on the above findings. That is, the stripping solution for multistage treatment of etching residues according to the present invention is a stripping solution for multistage processing composed of at least two types of stripping solutions used in a complementary manner to strip away etching residues. One of the at least two types of stripping solution is a stripping solution having solubility of titanium and a titanium compound, and the other is a stripping solution containing at least a quaternary ammonium hydroxide. .

  Further, the etching residue peeling method according to the present invention is characterized in that the etching residue is peeled off using a multi-stage treatment peeling solution composed of the at least two kinds of peeling solutions.

  In the stripping method, a stripping solution having solubility of the titanium and the titanium compound may be allowed to act on the etching residue, and then the stripping solution containing at least the quaternary ammonium hydroxide may be allowed to act. And vice versa.

  The substrate having the space to be etched can be particularly preferably applied to a substrate in which a via hole is formed.

  Usually, the metal or metal compound derived from the wiring layer and the insulating layer in the residue is an aluminum compound and / or a silica compound, and the metal compound derived from the barrier metal in the residue is a titanium compound.

  The metal or metal compound derived from the barrier metal is actually titanium or a titanium compound. On the other hand, a stripping solution having solubility of the titanium and the titanium compound is used. As such a stripping solution, an aqueous solution containing at least hydrogen peroxide is used.

  The metal or metal compound derived from the wiring layer and insulating layer is an aluminum-based compound and / or a silica-based compound. On the other hand, a stripping solution containing at least a quaternary ammonium hydroxide can be used.

  The “stripping solution having solubility of titanium and titanium compound” constituting the stripping solution for multistage treatment of the present invention will be described in more detail. This stripping solution is basically an aqueous solution containing at least hydrogen peroxide, and the titanium oxide dissolving action itself of this aqueous solution is known. Various improved products have been proposed to further improve the solubility (peelability) of titanium and titanium compounds in this aqueous solution, and they can all be used as one type of stripping solution constituting the multistage processing stripping solution of the present invention. It is.

  The main component responsible for titanium oxide solubility is hydrogen peroxide. It is preferable to add carbonic acid and / or carbonate to the stripping solution containing hydrogen peroxide as a main component from the viewpoint of improving the solubility of titanium and the titanium compound. Since this stripping solution is suitably an aqueous solution, the carbonate must be soluble in water. In view of the application device of the present invention, this carbonate preferably contains no metal ions. Examples of such carbonates include ammonia and carbonate salts, amine and carbonate salts, and quaternary ammonium salts. Of carbonate. Of these, ammonium carbonate is most preferred, which usually circulates as a mixture of ammonium carbonate, ammonium hydrogen carbonate, and ammonium carbamate, and these mixtures may be used.

  The “stripping solution having solubility of titanium and titanium compound” in the present invention is an aqueous solution, and water as the solvent may be used alone or in the form of a mixed solution with other organic solvents. It may be used in the form of an aqueous solution containing a salt, an acid, a base or the like.

  In the “peeling solution having solubility of titanium and titanium compound” constituting the stripping solution for multi-stage treatment of the present invention, the compounding ratio of carbonic acid and / or carbonate, hydrogen peroxide, and water depends on the application, use conditions, carbonic acid. Although it is not limited because it varies greatly depending on the type of salt, normally, the content of carbonic acid and / or carbonate is 0.01 to 40% by weight, and the content of hydrogen peroxide is 10 ppm based on the total weight of the titanium stripping solution. 35% by weight, water content of 25-99% by weight is preferred, carbonic acid (salt) content of 0.05-25% by weight, hydrogen peroxide content of 50 ppm-25% by weight, water content of 30- 95% by weight is further preferred.

  If the carbonic acid (salt) is less than 0.01% by weight, the dissolution of the titanium oxide is so slow that it is not practical, and if it exceeds 40% by weight, the carbonic acid (salt) becomes difficult to dissolve in the aqueous solution.

  Further, it has been pointed out that when the blending amount of hydrogen peroxide is less than 10 ppm, the dissolution of titanium oxide is so slow that it is impractical, and hydrogen peroxide exceeding 35% by weight increases the risk.

  When the amount of water, which is a solvent, is less than 25% by weight, carbonic acid hardly dissolves in an aqueous solution. When the amount exceeds 99% by weight, the dissolution of titanium oxide deviates from the practical range downward.

  The “peeling solution having solubility of titanium and titanium compound” used in the present invention may further contain a water-soluble organic solvent in addition to the above composition. Such a water-soluble organic solvent that can be added is not particularly limited. For example, alcohols such as methanol, ethanol, propanol, and butanol, ethers such as tetrahydrofuran, alkoxy alcohols, alkylene glycols, carbonate esters, Esters such as methyl acetate and ethyl acetate, amides such as dimethylformamide, dimethylacetamide, methylpyrrolidone and dimethylimidazolidinone, sulfoxides such as dimethylsulfoxide, amine oxides such as dimethyldodecylamine oxide and methylmorpholine oxide, N -Lactams such as methyl-2-pyrrolidone. These may be used singly or in combination of two or more.

  The content of the water-soluble organic solvent that can be added in the “stripping solution having solubility of titanium and titanium compound” used in the present invention is preferably 0.1 to 70% by weight based on the total weight of the titanium stripping solution. More preferred is 50% by weight. When a water-soluble organic solvent is added, the stability of hydrogen peroxide increases, and damage to materials other than titanium oxide is reduced. It is pointed out that when the content of the water-soluble organic solvent is less than 1% by weight, the effect of adding the water-soluble organic solvent is small, and when it exceeds 70% by weight, the dissolution rate of the titanium oxide is so small that it is not industrial. ing.

  The other stripping solution constituting the stripping solution for multistage treatment of the present invention is “a stripping solution containing at least a quaternary ammonium hydroxide”. As other components, alkanolamine, a water-soluble organic solvent other than the alkanolamine, and at least one selected from water may be added, and further, an aromatic hydroxy compound, a benzotriazole compound and a mercapto group are contained. You may mix | blend at least 1 sort (s) chosen from a compound.

  Specific examples of the quaternary ammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, trimethylethylammonium hydroxide, and (2-hydroxyethyl) trimethylammonium. Hydroxide, (2-hydroxyethyl) triethylammonium hydroxide, (2-hydroxyethyl) tripropylammonium hydroxide, (1-hydroxypropyl) trimethylammonium hydroxide, methyltripropylammonium hydroxide, methyl Examples include tributylammonium hydroxide. Of these, tetrapropylammonium hydroxide is preferred because it is less corrosive to various metal layers.

  The blending amount of the quaternary ammonium hydroxide is preferably 0.01 to 10% by mass, particularly 0.1 to 5% by mass in the stripper. If the amount of the main component is too large, the Al wiring tends to be corroded. On the other hand, if the amount is too small, the peeling performance tends to be lowered.

  Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, 2- (2-aminoethoxy) ethanol, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine and the like can be mentioned. Of these, monoethanolamine, 2- (2-aminoethoxy) ethanol, N-methylethanolamine, and monoisopropanolamine are preferably selected.

  The blending amount of the alkanolamine is preferably 0.1 to 25% by mass, particularly 1 to 20% by mass in the stripping solution. If the blending amount of the water-soluble organic solvent is too small, the peeling performance tends to be lowered. On the other hand, if the blending amount is too large, corrosion of various metals tends to occur.

  The water-soluble organic solvent other than the alkanolamine may be an organic solvent that is miscible with water or other compounding ingredients. Specifically, sulfoxides such as dimethyl sulfoxide; dimethyl sulfone, diethyl sulfone, bis (2- Sulfones such as hydroxyethyl) sulfone and tetramethylenesulfone; amides such as N, N-dimethylformamide, N-methylformamide, N, N-dimethylacetamide, N-methylacetamide and N, N-diethylacetamide; N- Lactams such as methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone; 1,3-dimethyl- 2-Imidazolidinone, 1,3-Diethyl-2-imidazolidinone Imidazolidinones such as 1,3-diisopropyl-2-imidazolidinone; ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate And polyhydric alcohols such as diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and derivatives thereof. . Among these, N-methyl-2-pyrrolidone, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidinone are preferably used. As the water-soluble organic solvent other than the alkanolamine to be used, one or more of the above can be used.

  The blending amount of the water-soluble organic solvent other than the alkanolamine is preferably 30 to 80% by mass, particularly 40 to 75% by mass in the stripper. If the blending amount of the water-soluble organic solvent other than alkanolamine is too large, the peeling performance tends to be lowered. On the other hand, if the blending amount is too small, corrosion of various metals tends to occur.

  About the said water, it mix | blends as a remainder of another component.

  Furthermore, you may mix | blend at least 1 sort (s) chosen from an aromatic hydroxy compound, a benzotriazole compound, and a mercapto group containing compound. These additives function as anticorrosives that suppress invasion of various metals on the substrate by the stripping solution.

  Specific examples of the benzotriazole compound include benzotriazole, 5,6-dimethylbenzotriazole, 1-hydroxybenzotriazole, 1-methylbenzotriazole, 1-aminobenzotriazole, 1-phenylbenzotriazole, 1-phenylbenzotriazole, Hydroxymethylbenzotriazole, methyl 1-benzotriazolecarboxylate, 5-benzotriazolecarboxylic acid, 1-methoxy-benzotriazole, 1- (2,2-dihydroxyethyl) -benzotriazole, 1- (2,3-dihydroxypropyl ) Benzotriazole, or 2,2 ′-{[(4-methyl-1H-benzotriazol-1-yl) methyl] imino, commercially available from Ciba Specialty Chemicals as the “IRGAMET” series Bisethanol, 2,2 ′-{[(5-methyl-1H-benzotriazol-1-yl) methyl] imino} bisethanol, 2,2 ′-{[(4-methyl-1H-benzotriazole-1- Yl) methyl] imino} bisethane, 2,2 ′-{[(4-methyl-1H-benzotriazol-1-yl) methyl] imino} bispropane, and the like. Among these, 1- (2,3-dihydroxypropyl) -benzotriazole, 2,2 ′-{[(4-methyl-1H-benzotriazol-1-yl) methyl] imino} bisethanol, 2,2 ′ -{[(5-Methyl-1H-benzotriazol-1-yl) methyl] imino} bisethanol and the like are preferably used.

  The mercapto group-containing compound is preferably a compound having a structure having a hydroxyl group and / or a carboxyl group in at least one of the α-position and β-position of the carbon atom bonded to the mercapto group. Specific examples of such compounds include 1-thioglycerol, 3- (2-aminophenylthio) -2-hydroxypropyl mercaptan, 3- (2-hydroxyethylthio) -2-hydroxypropyl mercaptan, and 2-mercapto. Propionic acid, 3-mercaptopropionic acid and the like are preferable. Of these, 1-thioglycerol is particularly preferably used.

  Examples of the aromatic hydroxy compound include phenol, cresol, xylenol, catechol (= 1,2-dihydroxybenzene), tert-butylcatechol, resorcinol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, salicyl alcohol, p- Hydroxybenzyl alcohol, o-hydroxybenzyl alcohol, p-hydroxyphenethyl alcohol, p-aminophenol, m-aminophenol, diaminophenol, aminoresorcinol, p-hydroxybenzoic acid, o-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid Examples thereof include acid, 2,5-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, and 3,5-dihydroxybenzoic acid. Of these, catechol and pyrogallol are preferably used.

  These aromatic hydroxy compounds, benzotriazole compounds, and mercapto group-containing compounds are preferably blended in an amount of 0.1 to 25% by weight, particularly 0.2 to 20% by weight, based on the total amount of the stripping solution. It is preferable. When deviating from this range, for example, if it is less than the lower limit, corrosion of Al, Cu or the like is likely to occur. Conversely, even if it is added in excess of the upper limit, the effect according to the addition amount is not recognized.

  The stripping solution containing quaternary ammonium hydroxide is blended with an acetylene alcohol / alkylene oxide adduct in which alkylene oxide is added to acetylene alcohol as an optional additive component in order to improve permeability. May be. As this acetylene alcohol, for example, “Surfinol”, “Orphine” (all of which are manufactured by Air Product and Chemicals Inc.) are commercially available, and are preferably used. Among these, “Surfinol 104”, “Surfinol 82” or a mixture thereof is most preferably used in view of its physical properties. In addition, “Olfin B”, “Olfin P”, “Olfin Y” and the like can also be used.

  As the alkylene oxide added to the acetylene alcohol, ethylene oxide, propylene oxide or a mixture thereof is preferably used. The acetylene alcohol / alkylene oxide adduct is a substance known per se as a surfactant. These are commercially available as a series of “Surfinol” (produced by Air Product and Chemicals Inc.) or a series of “Acetylenol” (produced by Kawaken Fine Chemical Co., Ltd.), and are preferably used. In particular, in consideration of changes in water solubility and surface tension characteristics due to the number of ethylene oxide added, “Surfinol 440” (n + m = 3.5), “Surfinol 465” (n + m = 10), “Surfi” “Nol 485” (n + m = 30), “acetylenol EL” (n + m = 4), “acetylenol EH” (n + m = 10), or a mixture thereof is preferably used. In particular, a mixture of “acetylenol EL” and “acetylenol EH” is preferably used. Especially, what mixed "acetylenol EL" and "acetylenol EH" in the ratio of 2: 8-4: 6 (mass ratio) is used especially suitably. By blending this acetylene alcohol / alkylene oxide adduct, the permeability of the stripping solution itself can be improved and the wettability can be improved.

  When the acetylene alcohol / alkylene oxide adduct is blended, the amount is preferably about 0.05 to 5% by weight, particularly preferably about 0.1 to 2% by weight, based on the total amount of the stripping solution. When the blending amount exceeds the above range, the generation of bubbles is considered, the improvement in wettability is saturated, and further improvement of the effect cannot be expected even if it is added more, on the other hand, if less than the above range, the desired wettability It is difficult to obtain a sufficient effect.

  You may mix | blend an acidic compound further with the peeling liquid containing a quaternary ammonium hydroxide. Examples of such acidic compounds include hydrofluoric acid, acetic acid, glycolic acid, salicylic acid, and phthalic acid. When these acidic compounds are blended, the blending amount is preferably about 1% by mass or less. In addition, when an acidic compound is mix | blended, the effect that the peelability of Si type residue improves especially is acquired.

  As the metal wiring in the wiring structure targeted by the present invention, aluminum alloy (Al alloy) such as aluminum (Al); aluminum-silicon (Al-Si), aluminum-silicon-copper (Al-Si-Cu), etc. Pure titanium (Ti); titanium alloys (Ti alloy) such as titanium nitride (TiN) and titanium tungsten (TiW); pure copper (Cu) and the like, but not limited thereto.

  According to the stripping solution and the stripping method for multistage treatment of etching residues according to the present invention, an excellent stripping effect equal to or higher than that can be obtained without using a hydroxylamine stripping solution having a safety problem. .

  Examples of the present invention will be described in detail below. In addition, the Example shown below is only the illustration for demonstrating this invention suitably, and does not limit this invention at all.

Example 1
(Composition of stripping solution having solubility of titanium and titanium compound)
The stripping solutions A to D shown below (Table 1) were prepared as "stripping solutions having solubility of titanium and titanium compounds" constituting the stripping solution for multistage treatment of the present invention.

(Stripping solution containing quaternary ammonium hydroxide)
As the “stripping solution containing a quaternary ammonium hydroxide” constituting the stripping solution for multistage treatment of the present invention, the stripping solution of E shown below (Table 2) was prepared.

(Wiring board to be processed)
A substrate in which an Al-Si-Cu layer is formed on a substrate, a titanium nitride film is formed as a barrier metal layer on the Al-Si-Cu layer, and a plasma TEOS is further stacked thereon as an insulating layer Was used. In the insulating layer of the substrate, vias having a diameter of 300 nm were formed by dry etching, and residues due to the etching process remained inside.

(Peeling removal treatment conditions)
The substrate was immersed in stripping solutions A to D at 25 ° C. for 90 seconds. Thereafter, the substrate was washed with water to remove moisture on the surface of the substrate, and further immersed in the stripper E at 75 ° C. for 20 minutes. Thereafter, the substrate was washed with water to remove moisture from the substrate surface.

  The inside of the via hole was observed using a scanning microscope on the substrate after the peeling removal treatment. As a result, four types of treatments were attempted in which the combination of the stripping solution having solubility of titanium and titanium compound and the stripping solution containing at least quaternary ammonium hydroxide was changed. There was no residue deposit on the bottom. Moreover, although the surface state of the via hole side wall (insulating layer) and the bottom exposed surface (aluminum wiring layer) was observed, no damage due to the stripping solution was observed.

(Comparative Example 1)
The peeling process using only the peeling liquid C in Example 1 was performed on the substrate used in Example 1. The peeling treatment conditions were 40 ° C. and 10 minutes. There was no damage in the wiring layer and the insulating layer by this treatment. However, removal of the etching residue was insufficient, and peeling residue was observed.

(Comparative Example 2)
The peeling treatment using only the peeling liquid E used in Example 1 was performed on the substrate used in Example 1. As the stripping treatment conditions, the conditions of 75 ° C. and 20 minutes, which are standard treatment conditions for stripping solutions containing quaternary ammonium hydroxides, were adopted. Although there was no damage in the wiring layer and the insulating layer due to this treatment, the removal of the residue was insufficient, and a peeling residue was observed.

(Example 2)
In Example 1, the same treatment was performed except that the peeling treatment with the peeling solution E was performed first using the substrates having different etching conditions, and the washing treatment was followed by the peeling treatment with the peeling solution C. When the inside of the via hole of the substrate after processing was observed, neither the insulating layer nor the wiring layer was damaged, and no residue was present.

  As described above, the multistage treatment stripping solution and stripping method of the etching residue according to the present invention obtains an excellent stripping effect equivalent to or better than when a hydroxylamine stripping solution having universal stripping properties is used. It can be used safely without the dangers of handling like hydroxyamine.

Claims (13)

A stripping solution for multi-stage treatment composed of at least two types of stripping solutions used in a complementary manner to strip and remove etching residues,
One of the at least two types of stripping solutions is a stripping solution having solubility of titanium and a titanium compound, and the other is a stripping solution containing at least a quaternary ammonium hydroxide. Stripping solution for multistage processing.   The stripping solution for multistage treatment according to claim 1, wherein the stripping solution having solubility of titanium and a titanium compound is an aqueous solution containing at least hydrogen peroxide.   The stripping solution for multistage treatment according to claim 2, wherein the aqueous solution containing at least hydrogen peroxide further contains a carbonate.   The stripping solution having solubility of titanium and a titanium compound can preferentially remove at least etching residue caused by a barrier metal among etching residues. The stripping solution for multistage treatment according to Item.   The stripping solution for multistage treatment according to claim 4, wherein the metal forming the barrier metal is titanium and / or titanium nitride.   The stripping solution containing at least the quaternary ammonium hydroxide further contains at least one selected from alkanolamine, a water-soluble organic solvent other than the alkanolamine, and water. The stripping solution for multistage treatment according to any one of claims 1 to 5.   The stripping solution containing at least the quaternary ammonium hydroxide further contains at least one selected from an aromatic hydroxy compound, a benzotriazole compound, and a mercapto group-containing compound. The stripping solution for multistage treatment according to 6.   The stripping solution containing at least the quaternary ammonium hydroxide can preferentially remove at least the etching residue caused by the wiring layer and / or the insulating layer among the etching residue. The stripping solution for multistage treatment according to any one of claims 1 to 7.   The stripping solution for multistage treatment according to claim 8, wherein the metal forming the wiring layer and / or the insulating layer is an aluminum compound and / or a silica compound.   An etching residue removing method, comprising: removing an etching residue using a multi-step treatment stripping solution comprising at least two stripping solutions according to any one of claims 1 to 9. .   A stripping solution having solubility in titanium and a titanium compound is allowed to act on the substrate on which the etching residue is formed, and then a stripping solution containing at least a quaternary ammonium hydroxide is allowed to act on the substrate. The method for removing an etching residue according to claim 10.   A stripping solution containing at least quaternary ammonium hydroxide is allowed to act on the substrate on which the etching residue is formed, and then a stripping solution having solubility in titanium and a titanium compound is allowed to act on the substrate. The method for removing an etching residue according to claim 10.   13. The etching residue peeling method according to claim 10, wherein the substrate on which the etching residue is formed is a substrate on which at least a via hole is formed.