HK1078102B - Aqueous stripping and cleaning composition - Google Patents

Description

Aqueous stripping and cleaning compositions

Background

In the production of semiconductors or semiconductor microcircuits, it is necessary to remove some substance from the substrate surface of a semiconductor device. In some examples, the material to be removed is a polymeric composition known as a photoresist. In other examples, the species to be removed is a residue or simply a contaminant of an etching or ashing process. The purpose of the stripping and/or cleaning composition is to remove unwanted materials from the semiconductor substrate without etching, dissolving or darkening the exposed surface of the substrate.

There are many different compositions for stripping photoresist and/or washing etch residues, ash or other contaminants from semiconductor substrates. For example, some patents issued to Allied Signal disclose non-aqueous organic stripping compositions comprising one or more organic sulfonic acids, organic solvents, and various modifiers. The first patent, US4,165,295, discloses a composition for removing polymeric organic materials such as photoresist comprising one or more organic sulfonic acids, one or more organic solvents, optionally phenol and from about 5 to about 250ppm of fluoride ion. A second patent, US4,215,005, provides an improved composition containing both fluoride and a complexing agent containing nitrogen having an available unshared pair of electrons. The third patent US4,221,647 provides another improved composition wherein 0.01-5% by weight of a nitrile compound is added to the composition. A fourth patent, US4,242,218, discloses a phenol-free stripping composition comprising a sulfonic acid in admixture with a chlorinated aryl compound, an alkylaryl compound having from 1 to 14 alkyl carbon atoms, an isoparaffin, or mixtures thereof.

US5,308,745 discloses alkali-containing compositions for stripping photoresists having reduced metal corrosion comprising a nitrogen-free weak acid having a PK of 2.0 or greater in aqueous solution and an equivalent weight of less than about 140. The weak acid is present in an amount to neutralize 19% to 75% of the amine present in the composition. US5,972,862 discloses a cleaning solution for semiconductor devices comprising a fluoride-containing compound, a water-soluble organic solvent, an inorganic or organic acid and optionally a quaternary ammonium salt or carboxylic acid ammonium salt and/or an organic carboxylic acid amine salt. US6,231,677 discloses the use of one or more carboxylic acids in a stripping composition. WO00/02238 discloses a chemical detergent based on a choline compound such as choline hydroxide. The composition consists of a choline compound, water and an organic solvent. The composition may additionally contain hydroxylamine and corrosion inhibitors.

Disclosure of Invention

The present invention relates to aqueous compositions useful for removing photoresist, etch and ash residues and contaminants from semiconductor substrates. The aqueous composition has low surface tension, low viscosity, and is compatible with a variety of substrates including Al/Cu, Cu, Ti, W, Ta, TiN, W, or TaN, low-k materials such as Methylsilsequioxane (MSQ), Black Diamond, SiLK, and high-k materials such as Pt/BST/oxide, where BST is barium strontium tantalate.

The composition of the present invention consists essentially of:

A) 30-90% by weight of a water-soluble organic solvent selected from the group consisting of organic amines, amides, sulfoxides, sulfones, lactams, imidazolidinones, lactones, polyols, and mixtures thereof,

B)3 to 20 weight percent of a sulfonic acid or its corresponding salt selected from the group consisting of p-toluenesulfonic acid, 1, 5-naphthalenedisulfonic acid, 4-ethylbenzene sulfonic acid, dodecylbenzene sulfonic acid, isopropylbenzene sulfonic acid, methylethylbenzene sulfonic acid, isomers of xylene sulfonic acid and mixtures thereof; and

C) 5-50% by weight of water.

The composition also optionally contains an anti-corrosion agent.

The compositions of the present invention do not contain fluoride-containing compounds and inorganic amines.

The present invention also relates to a method of removing photoresist, etch and/or ash residue, or contaminants from a semiconductor substrate comprising: the semiconductor substrate is contacted with the inventive composition as described above for a time sufficient to remove the photoresist, etch and/or ash residue, or contaminants.

Detailed Description

The present invention relates to aqueous compositions useful for removing photoresist, etch and ash residues and contaminants from semiconductor substrates. The composition is comprised of a water soluble organic solvent, a sulfonic acid or its corresponding salt, water and optionally an anti-corrosion agent.

The water-soluble organic solvent includes organic amine, amide, sulfoxide, sulfone, lactam, imidazolone, lactone, polyol and the like. Examples of organic amines include monoethanolamine, N-methylethanolamine, 1, 2-ethylenediamine, 2- (2-aminoethylamino) ethanol, diethanolamine, dipropylamine, 2-ethylamino ethanol, dimethylaminoethanol, cyclohexylamine, benzylamine, pyrrole, pyrrolidine, pyridine, morpholine, piperidine, oxazole and the like. Examples of the amide include N, N-dimethylformamide, dimethylacetamide, diethylacetamide, and the like. Examples of sulfoxides include dimethyl sulfoxide. Examples of sulfones include dimethyl sulfone and diethyl sulfone. Examples of lactams include N-methyl-2-pyrrolidone and imidazolinone. Examples of lactones include butyrolactone and valerolactone. Examples of polyols include ethylene glycol, propylene glycol, ethylene glycol monomethyl ether acetate, and the like. Examples of preferred water-soluble organic solvents include monoethanolamine, N-methylethanolamine, dimethyl sulfoxide and dimethylacetamide. These water-soluble organic solvents may be present alone or in combination. The water-soluble organic solvent is present in an amount of 30 to 90 wt%, preferably 30 to 85 wt%, most preferably 45 to 80 wt%, based on the total weight of the composition.

In addition to the water-soluble organic solvent, the composition also contains a sulfonic acid or its corresponding salt. Examples of suitable sulfonic acids include p-toluenesulfonic acid, 1, 5-naphthalenedisulfonic acid, 4-ethylbenzene sulfonic acid, dodecylbenzene sulfonic acid, isopropylbenzene sulfonic acid, methylethylbenzene sulfonic acid, isomers of xylene sulfonic acid and the corresponding salts of the above sulfonic acids. Examples of the sulfonate include ethanolammonium p-methylsulfonate and triethanolammonium p-methylsulfonate. The sulfonic acids and their corresponding salts may be present in the composition as the individual acids or salts, or as a mixture of sulfonic acids or salts thereof. The sulfonic acid or corresponding salt thereof is present in an amount of 3 to 20% by weight, preferably 3 to 10% by weight, based on the total weight of the composition.

Water is an essential component of the stripping and cleaning compositions of the present invention. Water comprises from 5 to 50 wt%, preferably from 5 to 35 wt%, most preferably from 10 to 30 wt% of the total weight of the composition.

Optionally, the stripping and cleaning composition contains an anti-corrosion agent. A single corrosion inhibitor compound or a mixture of corrosion inhibitors may be used in the stripping and scrubbing composition. Examples of corrosion inhibitors include benzotriazole, benzoic acid, malonic acid, gallic acid, catechol, ammonium malonate, and the like. The corrosion inhibitor is present in the stripping and cleaning composition in an amount of less than or equal to 20 wt%, preferably from 0.1 to 15 wt%, based on the total weight of the stripping and cleaning composition.

Other conventional known ingredients such as dyes, biocides, and the like may also be included in the stripping and cleaning composition in a total amount of less than or equal to 5 wt%, based on the total weight of the stripping and cleaning composition.

The stripping and cleaning compositions of the present invention are prepared by mixing the components in a vessel at room temperature until the solids are dissolved. Examples of such stripping and cleaning compositions are listed in table 1.

TABLE 1

Compound/formulation #	1	2	3	4	5	6	7	8	9	10	11	12	13
														MEA	70.0	71.0	70.0	-	70.0	70.0	70.0	72.0	-	-	71.0	73.5	72.0
NMEA	-	-	-	70.0	-	-	-	-	-	-	-	-	--
														DMSO	-	-	-	-	-	-	-	-	71.0	-	-	-	-
DMAc	-	-	-	-	-	-	-	-	-	71.0	-	-	--
														ToSA	7.0	7.0	7.0	-	7.0	7.0	7.0	7.0	7.0	7.0	-	7.0	-
NDSA	-	-	-	5.0	-	-	-	-	-	-	-	-	-
														EBSA	-	-	-	-	-	-	-	-	-	-	7.0	-	-
DBSA	-	-	-	-	-	-	-	-	-	-	-	-	5.0
														Deionized water	20.5	19.5	19.5	23.0	22.0	21.5	21.0	19.0	19.5	19.5	19.5	19.5	20.5
Gallic acid	1.5	1.5	1.5	1.0	-	0.5	1.0	1.0	1.5	1.5	1.5	-	1.5
														Benzotriazole compounds	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	1.0	-	1.0

MEA-monoethanolamine ToSA-p-toluenesulfonate NMEA-N-methylethanolamine NDSA-1, 5-naphthalenedisulfonic acid

DMSO ═ dimethyl sulfoxide EBSA ═ 4-ethylbenzene sulfonic acid DMAc ═ dimethyl acetamide DBSA ═ dodecylbenzenesulfonic acid

The aqueous stripping and cleaning compositions are useful for removing post-etch and ash, organic and inorganic residues, and polymeric residues from semiconductor substrates at low temperatures and low corrosion. Typically, the stripping and washing process with the composition of the present invention is carried out by immersing the substrate in the stripping/washing composition at 25-80 ℃ for 3 minutes to 1 hour. However, the compositions of the present invention may be used in any method known in the art that utilizes a liquid to remove photoresist, etch or ash residues and/or contaminants.

The following are examples of the use of the composition of the present invention, and the present invention is not limited to these examples.

Example 1

Positive photoresist was spin coated on a substrate of chemical vapor deposited Al-Cu film on a silicon wafer. The positive photoresist consisted of diazonaphthoquinone and a novolak resin, and the photoresist coating was baked at 90 ℃ for 90 seconds. A pattern is defined in the photoresist by exposing the wafer to i-line (365nm) radiation through a patterned mask and subsequent development. With Cl₂/BCl₃The etching gas mixture plasma etches the patterned wafer at a pressure of 5 torr and 20 ℃. Patterning the etched pattern onOxygen plasma ashing was performed at 65 ℃ for 55 seconds at a pressure of 0.3 torr.

The patterned and ashed wafer was immersed in a bath containing formulation 3 in table 1 at 65 ℃ for 30 minutes. The washed wafer was analyzed by examining the SEM image of the wafer. The SEM pictures showed that the wafer was cleaned and that there was no residue and no evidence of corrosion.

Example 2

TEOS (tetraethoxy silicate) is coated on top of a TiN anti-reflection coating (ARC), which in turn is coated on top of an Al-Cu layer, which is chemically deposited on the silicon wafer. A positive photoresist was spin coated over the TEOS layer. The coated photoresist was baked at 90 ℃ for 90 seconds. A pattern is defined in the photoresist by exposing the wafer to i-line radiation through a patterned mask and subsequent development. The pattern is transferred from the photoresist layer to the substrate using a two-step plasma process. The first step consists in subjecting the wafer to CO/CF for a TEOS layer₄/Ar/CHF₃Plasma etching gas mixture, followed by in situ Ar/CF for TiN ARC layer₄/O₂The plasma etches the gas mixture. The etched pattern was ashed with oxygen plasma at a pressure of 0.3 torr and 60 c for 150 seconds. The etched and ashed wafers were immersed in a bath containing formulation 3 for 30 minutes at 65 ℃. The washed wafer was analyzed by examining the SEM image of the wafer. The SEM showed that the wafer was cleaned and had no residue and no signs of corrosion.

Claims (9)

1. A composition for removing etching and/or ashing residue or contaminants from a semiconductor substrate consisting essentially of:

A) 30-90% by weight of a water-soluble organic solvent selected from the group consisting of organic amines, amides, sulfoxides, sulfones, lactams, imidazolidinones, lactones, polyols, and mixtures thereof,

B)3 to 20 weight percent of a sulfonic acid or its corresponding salt selected from the group consisting of p-toluenesulfonic acid, 1, 5-naphthalenedisulfonic acid, 4-ethylbenzene sulfonic acid, dodecylbenzene sulfonic acid, isopropylbenzene sulfonic acid, methylethylbenzene sulfonic acid, isomers of xylene sulfonic acid and mixtures thereof; and

C) 5-50% by weight of water.

2. The composition of claim 1, further comprising an anti-corrosion agent.

3. The composition of claim 1, wherein the water soluble organic solvent is monoethanolamine, N-methylethanolamine, dimethylsulfoxide, dimethylacetamide, or mixtures thereof.

4. The composition of claim 2, wherein the corrosion inhibitor is gallic acid, catechol, benzotriazole, benzoic acid, malonic acid, ammonium malonate, or a mixture thereof.

5. The composition of claim 2 wherein the corrosion inhibitor is present in an amount of 20% by weight or less.

6. The composition of claim 5 wherein the corrosion inhibitor is present in an amount of 0.1 to 15% by weight.

7. A composition as claimed in any one of claims 1 to 6, wherein the water-soluble organic solvent is present in an amount of 45 to 90% by weight and the sulphonic acid or corresponding salt is present in an amount of 3 to 10% by weight.

8. A composition as claimed in any one of claims 1 to 6, wherein the water-soluble organic solvent is present in an amount of 30 to 85% by weight.

9. A method of removing photoresist, etch and/or ash residue, or contaminants from a semiconductor substrate, comprising: contacting the semiconductor substrate with the composition of any one of the preceding claims for a time sufficient to remove the photoresist, etch and/or ash residue, or contaminant.