TWI746419B - Photoresist stripper solutions - Google Patents

Abstract

The disclosure is directed solutions and processes to remove substances from substrates. The substances can include photoresist. The solutions can include dimethylsulfoxide, a quaternary ammonium hydroxide, an alkanolamine, and less than 3% by weight water of a total weight of the solution. The quaternary ammonium hydroxide can include tetramethylammonium hydroxide, dimethyldipropylammonium hydroxide, or methyltriethylammonium hydroxide. Additionally, the solutions can include a secondary solvent. For example, the secondary solvent can include an alcohol. In another example, the secondary solvent can include ethylene glycol. Methods for the preparation and use of the solution to remove substances from substrates are also described.

Description

Photoresist stripping solution

This application is part of the continuation of U.S. Application No. 13/759,237 filed on February 5, 2013. The 13/759,237 case is a continuation of 12/091,808 filed on October 24, 2006. The 12 The /091,808 case is a continuation of the U.S. Application No. 11/260,912 filed on October 28, 2005, each of which is incorporated herein by reference in its entirety.

This disclosure generally relates to a composition capable of effectively removing photoresist from a substrate and its use method. The disclosed compositions are stripping solutions for removing photoresist. These solutions can maintain liquids at temperatures below normal room temperature and temperatures commonly encountered in transportation and storage, and additionally have the removed photoresist Favorable load capacity of the material. Stripping solutions with reduced water content have proven to be particularly effective in removing photoresist cleanly, providing low copper etch rates, and increasing the solubility of the photoresist in the stripping solution (as evidenced by lower particle counts).

Broadly speaking, the first aspect of the present disclosure provides a photoresist stripping solution that effectively removes or strips the photoresist from the substrate. Used in some manufacturing facilities to maintain liquid at temperatures below normal room temperature encountered. The composition of the present disclosure can remain liquid at a temperature as low as about -20°C to about +15°C. The composition of the present disclosure may contain dimethyl sulfide (DMSO), quaternary ammonium hydroxide, and alkanolamine. A preferred embodiment contains about 20% to about 90% dimethyl sulfide, about 1% to about 7% quaternary ammonium hydroxide and about 1% to about 75% alkanolamine (having at least two carbon atoms, At least one amine group substituent and at least one hydroxy substituent group, which can be attached to two different carbon atoms of the alkanolamine). The quaternary group may include (C ₁ -C ₈ )alkyl, arylalkyl, and combinations thereof. An example of quaternary ammonium hydroxide is tetramethylammonium hydroxide. The 1,2-alkanolamine may include compounds of the following formula:

Wherein R ¹ can be H, C ₁ -C ₄ alkyl or C ₁ -C ₄ alkylamino. The alkanolamine of formula I may have R ¹ _{which is H or -CH 2} CH ₂ NH _2. The solution of the present disclosure may also include another or second solvent. For example, the second solvent may include glycol, glycol ether, and the like. In another example, the second solvent may include alcohol. Specifically, the second solvent may include a polyhydroxy compound having two or more hydroxyl groups. Desirably, at least one hydroxyl group is a primary hydroxyl group, or at least two hydroxyl groups are a primary hydroxyl group.

The second aspect of the present disclosure provides a method for removing photoresist and related polymeric materials from the substrate using the stripping solution described herein. The photoresist can be removed from the selected substrate with photoresist thereon by the following methods: contact the substrate with the stripping solution for a time sufficient to remove the desired amount of photoresist, remove the substrate from the stripping solution, and rinse the substrate with the solvent The solution is peeled off and the substrate is dried.

The third aspect of the present disclosure includes electronic devices manufactured by the disclosed novel method.

The fourth aspect of the present disclosure includes a preferred stripping solution containing dimethyl sulfoxide, quaternary ammonium hydroxide, alkanolamine, and an optional second solvent with a reduced amount of water. The solutions may have a dryness coefficient of at least about 1. The solutions may also have a dryness coefficient of at least about 1.8, where the dryness coefficient (DC) is defined by the following equation:

The fifth aspect of the present disclosure includes the method of removing the photoresist from the substrate using the stripping solution described herein. The method involves selecting the substrate on which the photoresist is deposited, so that the substrate including the photoresist and the stripping solution (containing dimethyl sulfoxide, quaternary ammonium hydroxide, alkanolamine, optional second solvent The solution has a dryness coefficient of at least about 1) contact, keep the substrate away from no longer contacting the stripping solution and rinse the stripping solution from the substrate.

The sixth aspect of the present disclosure includes an electronic device prepared in part by the method described above.

The seventh aspect of the present disclosure includes a method of providing a dry composition, the composition comprising dimethyl sulfoxide, quaternary ammonium hydroxide, alkanolamine, and an optional second solvent, wherein the solution has a dryness of at least about 1 Degree factor.

The eighth aspect of the present disclosure includes a method of obtaining quaternary ammonium hydroxide with reduced water content, which is achieved by forming a solution of quaternary ammonium hydroxide, undesired water, and sacrificial solvent, and The solution was subjected to reduced pressure using a slight temperature increase. During the treatment, a portion of the sacrificial solvent and water are removed. During this process, excessive heating should be avoided to prevent decomposition of the hydroxide. If necessary, the addition and removal of sacrificial solvent and water can be repeated until the water content is sufficiently reduced.

The ninth aspect of the present disclosure includes a method of maintaining a low water content in the stripping solution. The method involves selecting a dry stripping solution, establishing contact between the stripping solution and the molecular sieve, and maintaining contact with the sieve until the stripping solution is used. This method is particularly useful for maintaining the peeling solution in a dry form after manufacturing, during storage and/or shipping, and after the container of the solution is opened.

For the purpose of facilitating understanding of the claimed content, reference will now be made to the illustrated embodiments and specific language will be used to illustrate these embodiments. However, it should be understood that it is not intended to limit the scope of the claimed content, as those skilled in the field involved in this disclosure can usually imagine, covering the changes and other modifications described in the claimed content and their principles. These other applications.

The composition of the present disclosure includes dimethyl sulfide (DMSO), quaternary ammonium hydroxide, and alkanolamine. The alkanolamine may have at least two carbon atoms, at least one amine group substituent, and at least one hydroxy substituent, wherein the amine group and the hydroxy substituent are attached to two different carbon atoms of the alkanolamine. The quaternary substituents may include (C ₁ -C ₈ )alkyl, benzyl, and combinations thereof. The composition can have less than about + -20 ℃ up to about the freezing point of 15 deg.] C and about 15cm ³ / well was raised up to about 90cm ³ / liter of the load capacity. For dry stripping solutions, the quaternary substituents may include C ₁ -C ₄ alkyl groups, aryl alkyl groups, or combinations thereof.

Formulas with increased alkanolamine content are particularly non-corrosive to carbon steel, and are less harmful to typical waste treatment systems and auxiliary equipment than other stripping solutions. The composition may include a 1,2-alkanolamine having the following formula:

Wherein R ¹ is hydrogen, (C ₁ -C ₄ )alkyl or (C ₁ -C ₄ )alkylamino. The formulation of the solution may additionally include a second solvent. The formulation of the solution may include about 2% to about 75% of the second solvent. The second solvent may include glycols and their alkyl or aryl ethers described in more detail below. In addition, in some cases, the second solvent may include alcohol. Specifically, the second solvent may include a polyhydroxy compound having two or more hydroxyl groups. The formulation may have a freezing point sufficiently lower than 25°C to minimize freezing during transportation and storage. The formulation can also have a freezing point below about 15°C. Since the peeling solution can keep the liquid at low temperature, it can eliminate or minimize the need to liquefy the solidification roller of the peeling solution received during cold weather or stored in an unheated warehouse before the solution can be used. The use of the roller heater for melting the solidified peeling solution is time-consuming, requires additional treatment, and can cause incomplete melting and modification of the melting solution composition.

In addition, the composition of the present disclosure exhibits a high loading capacity, thereby enabling the composition to remove a higher content of photoresist without sedimentation of solids. Loading capacity is defined as the number ^{of cm 3} of photoresist or double-layer material that can be removed per liter of stripping solution before the material is redeposited on the wafer or before the residue remains on the wafer. For example, if 20 liters of stripping solution can remove 300 cm ^{3 of} photoresist before redeposition occurs or residues remain on the wafer, the load capacity is 300 cm ³ /20 liters = 15 cm ³ / liter.

The composition generally contains about 55% to about 95% solvent, with all or most of the solvent being DMSO. In an illustrative example, the solution may include DMSO in an amount included in the range of about 70% by weight to about 90% by weight of the total weight of the solution. Additionally, the composition may include about 2% to about 10% quaternary ammonium hydroxide. In some cases, the solution may include quaternary ammonium hydroxide in an amount ranging from about 1% to about 7% by weight of the total weight of the solution. The quaternary substituents may include (C ₁ -C ₈ )alkyl, benzyl, and combinations thereof.

When used, the second solvent usually constitutes about 2% to about 35% of the composition. In an illustrative example, the solution may include the second solvent in an amount included in the range of about 5 wt% to about 20 wt% of the total weight of the solution. The release formulation may also contain optional surfactants, the content of which is usually in the range of about 0.01% to about 3% by weight of the total weight of the solution. A suitable amount of alkanolamine can range from about 2% to about 75% of the composition. For example, the amount of alkanolamine in the solution can be included in the range of about 3% to about 15% by weight of the total weight of the solution. Since some of the components of the stripping solution can be provided as an aqueous solution, the composition may contain a small amount of water as appropriate. All% provided herein are weight% based on the weight of the composition.

The quaternary ammonium hydroxide may include alkyl ammonium hydroxide. For example, quaternary ammonium hydroxide may include tetramethyl ammonium hydroxide, diethyl dimethyl ammonium hydroxide, dipropyl dimethyl ammonium hydroxide, ethyl trimethyl ammonium hydroxide, tetrabutyl ammonium hydroxide Ammonium, benzyl trimethyl ammonium hydroxide. In an illustrative example, the solution may include one or more of tetramethylammonium hydroxide, dimethyldipropylammonium hydroxide, or methyltriethylammonium hydroxide.

The alkanolamine can have at least two carbon atoms and the amine group and the hydroxyl substituent can be located on different carbon atoms. Suitable alkanolamines include (but are not limited to) ethanolamine, N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, N-butylethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N -Ethyldiethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyl isopropanolamine, N-ethyl isopropanolamine, N-propyl isopropanolamine, 2-aminopropane-1-ol, N-methyl-2-aminopropane-1-ol, N-ethyl-2-aminopropane-1-ol, 1-aminopropane-3-ol, N-methyl-1-aminopropane-3-ol, N-ethyl-1-aminopropan-3-ol, 1-aminobutane-2-ol, N-methyl-1-amino Butane-2-ol, N-ethyl-1-aminobutan-2-ol, 2-aminobutan-1-ol, N-methyl-2-aminobutan-1-ol, N-ethyl-2-aminobutane-1-ol, 3-aminobutane-1-ol, N-methyl-3-aminobutane-1-ol, N-ethyl-3- Aminobutan-1-ol, 1-aminobutane-4-ol, N-methyl-1-aminobutane-4-ol, N-ethyl-1-aminobutane-4-ol Alcohol, 1-amino-2-methylpropane-2-ol, 2-amino-2-methylpropane-1-ol, 1-aminopentane-4-ol, 2-amino-4-ol Methylpentane-1-ol, 2-aminohexane-1-ol, 3-aminoheptan-4-ol, 1-aminooctane-2-ol, 5-aminooctane-ol , 1-aminopropane-2,3-polyhydroxy compound, 2-aminopropane-1,3-polyhydroxy compound, tris(oxymethyl)aminomethane, 1,2-diaminopropane-3 -Alcohol, 1,3-diaminopropan-2-ol and 2(2-aminoethoxy)ethanol.

The second solvent may include a glycol ether solvent, an alcohol or a polyhydroxy compound, or a combination of two or more of these compounds.

Glycol ether solvents may include (but are not limited to) diethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol Alcohol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monoiso Propyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monoanisole, diethylene glycol diethyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether Ether, polyethylene glycol monomethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl acetate, dipropylene glycol, tripropylene glycol, propylene glycol monomethyl Ether, propylene glycol dimethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoisopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol dipropyl ether, two Propylene glycol diisopropyl ether, tripropylene glycol and tripropylene glycol monomethyl ether, 1-methoxy-2-butanol, 2-methoxy-1-butanol, 2-methoxy-2-methyl-2- Butanol, 3-methoxy-3-methyl-1-butanol, dioxane, trioxane, 1,1-dimethoxyethane, tetrahydrofuran, crown ether and the like.

The second solvent alcohol and polyhydroxy compound have two or more hydroxyl groups and do not contain ester, amine or ether groups. The alcohol or polyhydroxy compound may be an aliphatic compound, an alicyclic compound, a cyclic compound, or an aromatic compound, but is desirably an aliphatic compound or an alicyclic compound. The alcohol or polyhydroxy compound may be a saturated or unsaturated compound, and desirably has one or less than one unsaturated bond, or no unsaturated bond. Alcohols and polyhydroxy compounds desirably contain no heteroatoms. Alcohols and polyhydroxy compounds desirably contain only carbon and hydrogen atoms.

As an example of the second solvent, the alcohol can mention linear and branched chain and aromatic compound alcohols. For illustration, the alcohol of the solution may include methanol, ethanol, propanol, isopropyl alcohol, butanol, tertiary-butyl alcohol, tertiary-pentyl alcohol, 3-methyl-3-pentanol, 1- Octanol, 1-decanol, 1-undecyl alcohol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 9-hexadecene- 1-alcohol, 1-heptadecanol, 1-octadecyl alcohol, 1-nonadecanol, 1-eicosanol, 1-eicosanol, 1-docosyl alcohol, 13-docosene-1 -Alcohol, 1-Ticosanol, 1-Dihexanol, 1-Dihexanol, 1-Dioctacosanol, 1-Triacontanol, 1-Triacontanol, 1-Tritetracosanol , Cetearyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol. In an illustrative example, the solution may include one or more of furfuryl alcohol, tetrahydrofurfuryl alcohol, tertiary-butyl alcohol, or 3-methyl-3-pentanol.

As mentioned above, the second solvent may be a polyhydroxy compound having two or more hydroxyl groups. The molecular weight of the polyhydroxy compound desirably does not exceed 500, or does not exceed 400, or No more than 350, or no more than 300, or no more than 275, or no more than 250, or no more than 225, or no more than 200, or no more than 175, or no more than 150, or no more than 125, or no more than 100, or Not more than 75.

The polyhydroxy compound as the second solvent may include ethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,2,3-propanetriol, 1,2-butanediol, 1,3 -Propylene glycol, 2,3-butanediol, 1,4-butanediol, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2-pentanediol, 1,3 -Pentanediol, 1,4-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 3,4-pentanediol, 1,2,3-pentanetriol, 1,2 ,4-Pentanetriol, 1,2,5-Pentanetriol, 1,3,5-Pentanetriol, etohexadiol, p-methane-3,8-polyol, 2-methyl- 2,4-pentanediol, 2,2-dimethyl-1,3-propanediol, glycerin, trimethylolpropane, xylitol, arabitol, 1,2- or 1,3-cyclopentanediol , 1,2- or 1,3-cyclohexanediol, 2,3-norbornanediol, 1,8-octanediol, 1,2-cyclohexane-dimethanol, 1,3-cyclohexane Alkyl dimethanol, 1,4-cyclohexane dimethanol, 2,2,4-trimethyl-1,3-pentanediol, hydroxypivalic acid hydroxypivaloyl ester, 2-methyl-1, 3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,6-hexanediol, 2,2,4 ,4-Tetramethyl-1,6-hexanediol, 1,10-decanediol, 1,4-benzenedimethanol, hydrogenated bisphenol A, 1,1,1-trimethylolpropane, 1, 1,1-Trimethylolethane, neopentylerythritol, erythritol, threitol, dineopentitol, sorbitol and the like, and one of two or more of the above-mentioned polyhydroxy compounds combination.

In an illustrative example, the solution may include ethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,4-pentanediol, 1,2-butanediol, or 1,3-butanediol One or more of the second polyhydroxy solvents of alcohol.

The composition may optionally contain one or more corrosion inhibitors. Suitable corrosion inhibitors include, but are not limited to, aromatic hydroxy compounds such as catechol; alkyl catechol (such as methyl catechol, ethyl catechol and tertiary butyl catechol) Phenol), phenol and gallic phenol; aromatic triazoles, such as benzotriazole; alkyl benzotriazole; carboxylic acids, such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, oxalic acid, malonic acid, Succinic acid, glutaric acid, Maleic acid, fumaric acid, benzoic acid, phthalic acid, trimellitic acid, glycolic acid, lactic acid, malic acid, citric acid, acetic anhydride, phthalic anhydride, maleic anhydride, Succinic anhydride, salicylic acid, gallic acid and gallic acid esters (such as methyl gallate and propyl gallate); organic salts and alkaline substances of the above-mentioned organic compounds containing carboxyl groups (such as ethanolamine) , Trimethylamine, diethylamine and pyridine (such as 2-aminopyridine and the like); and chelating compounds, such as phosphoric acid-based chelating compounds (including 1,2-propylenediaminetetramethylenephosphonic acid and hydroxyl Ethane phosphonic acid), carboxylic acid-based chelating compounds (e.g. ethylenediaminetetraacetic acid and its sodium and ammonium salts, dihydroxyethylglycine and nitrilotriacetic acid), amine-based chelating compounds (e.g. Bipyridine, tetraphenylporphyrin and phenanthroline), and oxime-based chelating compounds (such as dimethylglyoxime and diphenylglyoxime). Corrosion inhibitors can be used or a combination of corrosion inhibitors can be used. Corrosion inhibitors have proven useful at levels ranging from about 1 ppm to about 10%.

In addition, the solution may optionally include one or more surfactants, such as fluorosurfactants. An example of a fluorosurfactant that can be included in the solution is DuPont FSO (with polyethylene glycol (50%), ethylene glycol (25%), 1,4-dioxane (<0.1%), water ( 25%) fluorinated short-chain polymer B monoether).

A temperature of at least 50°C can be used to contact the substrate, and for most applications, a temperature of about 50°C to about 75°C can be used. For specific applications where the substrate is sensitive or requires a longer removal time, a lower contact temperature is more appropriate. For example, when reprocessing the substrate, the peeling solution can be appropriately maintained at a temperature of at least 20° C. for a long time to remove the photoresist and avoid damaging the substrate. If a longer contact time is required to completely remove the resist, placing a dry nitrogen coating on the stripping solution can reduce water absorption from the atmosphere and maintain the improved performance of the dry stripping solution.

When the substrate is immersed, the agitation of the composition additionally aids the removal of the photoresist. The agitation can be achieved by mechanical agitation, circulation, or by bubbling inert gas through the composition. After removing the desired amount of photoresist, keep the substrate away from the stripping solution and use water or alcohol. rinse. For example, deionized (DI) water can be used to rinse the substrate. In another example, isopropanol can be used to rinse the substrate. For substrates that subject the components to oxidation, rinsing can be performed under an inert atmosphere. The stripping solution of the present disclosure can have an improved photoresist material loading capacity compared with current commercial products, and a larger number of substrates can be processed with a given volume of the stripping solution.

The stripping solution provided in the present disclosure can be used to remove the polymeric resist material present in a single layer or some types of double-layer resists. For example, a two-layer resist usually has a first inorganic layer covered by a second polymer layer or may have two polymer layers. Using the method described in this article, a single layer of polymer resist can be effectively removed from a standard wafer with a single polymer layer. The same method can also be used to remove a single polymer layer from a wafer having a double layer consisting of a first inorganic layer and a second or outer polymer layer. Finally, two polymer layers can be effectively removed from a wafer having a double layer composed of two polymer layers. A dry stripping solution can be used to remove one, two or more resist layers.

The dry stripping solution may include dimethyl sulfide, quaternary ammonium hydroxide, alkanolamine, optional second solvent, and less than about 3 wt.% water. The second solvent may include glycol ethers, alcohols, and/or polyhydroxy compounds. The dry stripping solution may also include dimethyl sulfide, quaternary ammonium hydroxide, alkanolamine, glycol ether solvent, polyhydroxy second solvent, and a dryness coefficient of at least about 1.8. The dry stripping solution may also include dimethyl sulfide, quaternary ammonium hydroxide, alkanolamine, a second solvent (such as an alcohol or a polyhydroxy second solvent), and a dryness coefficient of at least about 1.8.

The use of the dry photoresist stripping solution is similar to that described above for the stripping solution with a low freezing point. However, it helps to maintain the stripping solution in a dry form before use and can minimize water absorption during its use by maintaining a normally dry environment in the area involved in the removal of the resist. The peeling solution can be maintained in a dry state by maintaining the contact between the peeling solution and the active molecular sieve after opening the container during storage, transportation and before using the peeling solution.

The dry stripping solution described in this article should be prepared from the dry component as much as possible. because Quaternary ammonium hydroxide is hygroscopic and is usually available as an aqueous solution or its hydrate, so it is usually necessary to remove the water contained in the solution or combined with the hydrate to provide a dry stripping solution with a dryness coefficient of at least about 1. The work of obtaining dry quaternary ammonium hydroxide and reaching a dry state at elevated temperatures usually results in the decomposition of the hydroxide. It has been surprisingly discovered that quaternary ammonium hydroxide in a volatile solvent can be pre-dried to obtain a solvent wet paste with reduced water content and no decomposition. The dry stripping solution containing quaternary ammonium hydroxide can be prepared by pre-drying the quaternary ammonium hydroxide and combining it with other substantially dry components to maintain a low water content, or subsequently drying from the water-containing component The initial formation of a fan-treated wet stripping solution.

The quaternary ammonium hydroxide in a pre-dried form can be obtained by subjecting the quaternary ammonium hydroxide in a hydrated or otherwise wet form to a reduced pressure using a very slight temperature increase. The removal of water can be aided by dissolving quaternary ammonium hydroxide in a solvent such as alcohol before subjecting the hydroxide to reduced pressure. Based on the work done so far using methanol, during the treatment, a large part of the water and alcohol are removed to provide an alcohol wet paste of quaternary ammonium hydroxide. Depending on the desired degree of dryness, additional dry alcohol can be added to the initial treated hydroxide and the treatment under reduced pressure can be repeated one or more times. The treatment can be carried out under a pressure of about 0.001 mmhg to about 30 mmhg and at a temperature up to at least about 35° C. without decomposing the quaternary ammonium hydroxide in a large amount. The treatment can also be carried out under a pressure of about 0.01 mmhg to about 10 mmhg.

For wet formulations with or without a second solvent, the stripping solution can be dried by contacting the stripping solution with a solid desiccant (for example, a combination of molecular sieve, calcium hydride, calcium sulfate or desiccant) after adding all the components . Example desiccants may include activated 3A or 4A molecular sieves. For dry stripping solutions containing a second solvent, quaternary ammonium hydroxide can be combined with any other wet components, and the resulting solution can be contacted with an active desiccant such as molecular sieve to separate the dry solution from the consumed desiccant and Any remaining dry components are added to the dry solution. Contact with molecular sieves or other solid desiccants can be done by any known method, for example, the desiccant is used to slurry the solution and filter the dry slurry. Similarly, you can use the string The wet solution is passed through agglomerated activated molecular sieve or other desiccant to dry any of the wet solutions described above. Suitable molecular sieves include 3A, 4A and 5A type sieves.

Molecular sieves can also be used as a drying agent (or desiccant) to maintain the peeling solution in a dry state. For example, the pellet form can be used because it allows the dry stripping solution to be removed by simple decantation. However, for applications where decantation does not provide sufficient separation, molecular sieves (whether powder or pellets) can be included in a "tea bag" arrangement that will allow equilibrium with the solution, but will not allow any sieve particles to contaminate the solution. The dry stripping solution containing molecular sieves can be maintained in a dry state for an extended period of time after the container has been opened, depending on the amount of molecular sieve included in the stripping solution, the surrounding humidity, and the amount of time to open the container.

Instance Example 1-14

The reactants listed in Table I were separately combined under stirring to obtain each of the 14 homogeneous stripping solutions. The freezing point was determined and is also provided in Table I. The compositions of Examples 1-14 may optionally be formulated without surfactants and formulated to include corrosion inhibitors.

Example 14

The silicon wafer with the photoresist thereon was immersed in the peeling solution of Example 1, and maintained at a temperature of about 70° C. for about 30 minutes to about 60 minutes with stirring. Remove the wafer and rinse with DI water Wash and dry. Inspection of the wafer will indicate the removal of virtually all photoresist. For some applications, good results can be obtained by immersing the wafer in the stripping solution and/or immersing the wafer for up to 150 minutes without stirring. The best way to remove the photoresist from the wafer can be easily determined without undue experimentation. This method can be used to remove a single layer of polymerized photoresist or two polymerized layers present in a double-layer resist with two polymer layers.

Example 15

The silicon wafer with photoresist on it was mounted in a standard spray device and sprayed with the stripping solution of Example 2, and maintained at about 50°C. The spray may be implemented in an inert atmosphere or in the presence of an active gas (such as oxygen, fluorine or silane) as appropriate. The wafers can be removed periodically and inspected to determine when enough photoresist is removed. When enough photoresist has been removed, the wafer can be rinsed with isopropanol and dried. This method can be used to remove a single layer of polymerized photoresist or two polymerized layers present in a double-layer resist with two polymer layers.

Example 16

The method described in Example f4 was used to remove the photoresist from the wafer described in Table II below. Use the three stripping solutions in a volume of 20 liters until the photoresist polymer remains on the wafer or until the polymer or its degradation products are deposited on the wafer again, at which point the solution loading capacity is reached. Using this method, the load capacity of the two stripping solutions described in the above Examples 1 and 2 and the general typical comparative example of the current commercial stripping solution were determined.

Example 17

Combine dimethyl sulfite (85.5g), diethylene glycol monomethyl ether (6.0g), aminoethylethanolamine (2.7g) and tetramethylammonium hydroxide pentahydrate (5.5g) to obtain A peeling solution with about 3wt.% water and a dryness coefficient of about 0.9. Agitate the mixture slightly to help dissolve the hydroxide pentahydrate. About 3wt.% of the water in the solution is essentially derived from the pentahydrate.

Example 18

Active 3A molecular sieves were added to three different samples of the peeling solution prepared according to the method of Example 17, and the contact with the peeling solution was maintained at ambient temperature for 72 hours. The sieves were removed by filtration and the moisture content of the initial and dry solution was determined by the Karl Fischer method. Store the dry stripping solution in a closed container. The spent sieve can be dried for reuse or discarded. Tabulate the specific details of this experiment in Table III below grid.

Example 19

Three silicon wafers with dry film photoresist based on negative acrylate polymer (120/μm) placed on the copper area were individually immersed in the three dry stripping solutions prepared in Example 18 and kept at 70°C Maintain for 60 minutes. Remove the samples and rinse with deionized water for one minute. A LiQuilaz SO5 particle analyzer was used to analyze the number of particles of the photoresist suspended in the solution in the stripping solution, and to determine the copper etching rate of each wafer. The results are tabulated in Table IV provided below. LiQuilaz is a registered trademark of Particle Measuring Systems, Inc. 5475 Airport Blvd., Boulder, Colorado, 80301.

The photoresist removal as described above can be carried out at a temperature in the range of about 70°C to about 80°C without taking any measures to remove water. However, when the photoresist removal is performed at a relatively low temperature of less than about 70°C, it can be helpful to take measures to minimize the absorption of moisture from the atmosphere. Providing a cover layer of dry nitrogen over the stripping solution maintained at less than about 70°C has proven to be effective in minimizing water absorption when the stripping solution is exposed to a humid atmosphere for a longer period of time. The ability of the dry stripping solution described above to dissolve a larger amount of photoresist and minimize the number of particles dispersed in the stripping solution can extend the effective life of the stripping solution and reduce Less overall cost.

Example 20

A 25wt.% solution of tetramethylammonium hydroxide pentahydrate in methanol was prepared, and 40.8 g of the solution was heated to about 30°C in a water bath and maintained at a pressure of about 0.01 mmhg for about 75 minutes. The condensate was collected in a Dewar flask cooled with liquid nitrogen. After about 75 minutes, the temperature of the water bath was raised to about 35°C and maintained at this temperature for another 105 minutes. A white paste is produced. The vacuum was broken and 85.8 g of dry DMSO was added to dissolve the white solid, and then 6.0 g of diethylene glycol monomethyl ether and 2.7 g of aminoethylethanolamine were added to obtain the peeling solution in a substantially dry form as set forth in Table 1 of Example 1. The Karl Fischer method found that the water content of the dry stripping solution was 0.71% and the solution contained less than 1% methanol. Lower water content can be obtained by adding additional methanol to the white paste and maintaining the resulting solution under reduced pressure for another 2 to 5 hours.

Example 21

An appropriate amount of dry peeling solution of the type described in Example 18 was filled with active molecular sieves to maintain the peeling solution under dry conditions for a longer period of time. For every 100 g of peeling solution maintained in a closed and sealed container, add about 5 grams to about 10 grams of active sieves. The preferred ones are molecular sieves in the form of pellets. However, if it is removed by filtration before use or if a small amount of particulate matter does not interfere with the use of the dry peeling solution, a powdered sieve can be used.

Although the applicant's disclosure content has been provided with reference to the above specific embodiments, it should be understood that those who practice the technology can make modifications and changes in the disclosed embodiments without departing from the spirit and scope of the disclosure. It is intended to cover all such modifications and changes.

Claims (20)

A photoresist stripping solution, comprising: dimethyl sulfoxide; quaternary ammonium hydroxide; alkanolamine, which has at least two carbon atoms and includes at least one amino substituent and at least one hydroxyl substituent, and Amino substituents and the at least one hydroxy substituent attached to different carbon atoms of the alkanolamine; water accounting for less than 3% by weight of the total weight of the photoresist stripping solution; and a second solvent comprising a polyhydroxyl group A compound, wherein the polyhydroxy compound does not contain ether, amine or ester linkages and wherein the amount of the polyhydroxy compound is in the range of about 5% to about 20% by weight of the total weight of the photoresist stripping solution. The photoresist stripping solution of claim 1, wherein the quaternary ammonium hydroxide includes alkyl ammonium hydroxide. According to the photoresist stripping solution of claim 2, wherein the alkyl ammonium hydroxide includes tetramethyl ammonium hydroxide, dimethyl dipropyl ammonium hydroxide or methyl triethyl ammonium hydroxide. The photoresist stripping solution of claim 1, wherein the polyhydroxy compound comprises propylene glycol. The photoresist stripping solution of claim 1, wherein the amount of the alkanolamine is included in the range of about 3% by weight to about 15% by weight of the total weight of the photoresist stripping solution. The photoresist stripping solution of claim 1, wherein the photoresist stripping solution further contains glycol ether. The photoresist stripping solution of claim 4, wherein the quaternary ammonium hydroxide comprises tetramethylammonium hydroxide, dimethyldipropylammonium hydroxide or methyltriethylammonium hydroxide and wherein the alkanolamine The amount is included in the range of about 3 wt% to about 15 wt% of the total weight of the photoresist stripping solution. The photoresist stripping solution of claim 7, wherein the amount of the dimethyl sulfoxide is included in the range of about 70% by weight to about 90% by weight of the total weight of the photoresist stripping solution. A photoresist stripping solution, which contains dimethyl sulfide; quaternary ammonium hydroxide, which includes tetramethylammonium hydroxide, dimethyldipropylammonium hydroxide or methyltriethylammonium hydroxide, benzene Methyl trimethyl ammonium hydroxide, diethyl dimethyl ammonium hydroxide; alkanolamine, which has at least two carbon atoms, at least one amino group substituent and at least one hydroxyl substituent group, the at least one amino group substituted Group and the at least one hydroxy substituent attached to different carbon atoms of the alkanolamine; water accounting for less than 3% by weight of the total weight of the photoresist stripping solution; and a second solvent comprising an alcohol, the alcohol selected From one or more of furfuryl alcohol, tetrahydrofurfuryl alcohol, tertiary butyl alcohol and 3-methyl-3-pentanol. The photoresist stripping solution of claim 9, wherein: the amount of the alkanolamine is included in the range of about 3% by weight to about 15% by weight of the total weight of the photoresist stripping solution; and the alkanolamine contains mono Ethanolamine. The photoresist stripping solution of claim 9, wherein the photoresist stripping solution further comprises a polyhydroxy compound selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4- Pentylene glycol, 1,2-butanediol or 1,3-butanediol. The photoresist stripping solution of claim 9, wherein the amount of the dimethyl sulfoxide is included in the range of about 70% by weight to about 90% by weight of the total weight of the photoresist stripping solution. The photoresist stripping solution of claim 9, wherein the amount of the quaternary ammonium hydroxide is included in the range of about 1% by weight to about 7% by weight of the total weight of the photoresist stripping solution. A photoresist stripping solution, which comprises: dimethyl sulfoxide; Dimethyldipropylammonium hydroxide; water accounting for less than 3% by weight of the total weight of the photoresist stripping solution; alkanolamine; and a second solvent, which includes alcohol, polyhydroxy compound or a combination thereof, and optionally two Alcohol ether compounds, where the alcohol and polyhydroxy compounds do not contain ether, amine or ester linkages. The photoresist stripping solution of claim 14, wherein the amount of the second solvent is included in the range of about 2% by weight to about 35% by weight of the total weight of the photoresist stripping solution. The photoresist stripping solution of claim 14, which further comprises a corrosion inhibitor included in an amount ranging from about 1 ppm to about 10% by weight of the total weight of the photoresist stripping solution. The photoresist stripping solution of claim 14, wherein: the amount of the dimethyl sulfide is included in the range of about 55 wt% to about 95 wt% of the total weight of the photoresist stripping solution; the dimethyl bismuth The amount of propylammonium hydroxide is included in the range of about 2% by weight to about 10% by weight of the total weight of the photoresist stripping solution; and the amount of the alkanolamine is included in the range of about 2% by weight to about 10% by weight of the total weight of the photoresist stripping solution. In the range of 2% by weight to about 75% by weight. The photoresist stripping solution of claim 14, wherein the alkanolamine has at least two carbon atoms, at least one amino group substituent and at least one hydroxyl substituent, the at least one amino substituent and the at least one hydroxyl substituent Attached to a different carbon atom of the alkanolamine. The photoresist stripping solution of claim 17, wherein the second solvent contains a polyhydroxy compound. The photoresist stripping solution of claim 17, wherein the amount of the second solvent is included in the range of about 2% by weight to about 35% by weight of the total weight of the photoresist stripping solution.