Stripper pretreatment

Disclosed are compositions useful for the pretreatment of polymeric material to be removed from substrates, such as electronic devices. The compositions of the present invention are particularly suitable for pretreating polymer residues from plasma etch processes. Also disclosed are methods of removing such pretreated polymeric material.

BACKGROUND OF THE INVENTION
 The present invention relates generally to the field of removal of
 polymeric materials from a substrate. In particular, the present invention
 relates to compositions and methods as pre-treatments for the removal of
 polymer material, and particularly plasma induced polymeric material, from
 electronic devices.
 Numerous materials containing polymers are used in the manufacture of
 electronic devices, such as circuits, disk drives, storage media devices
 and the like. Such polymeric materials are found in photoresists, solder
 masks, antireflective coatings, and the like. For example, modern
 technology utilizes positive-type resist materials for lithographically
 delineating patterns onto a substrate so that the patterns can be
 subsequently etched or otherwise defined into the substrate material. The
 resist material is deposited as a film and the desired pattern is defined
 by exposing the resist film to energetic radiation. Thereafter the exposed
 regions are subject to a dissolution by a suitable developer liquid. After
 the pattern has been thus defined in the substrate the resist material
 must be completely removed from the substrate to avoid adversely affecting
 or hindering subsequent operations or processing steps.
 It is necessary in such a photolithographic process that the photoresist
 material, following pattern delineation, be evenly and completely removed
 from all unexposed areas so as to permit further lithographic operations.
 Even the partial remains of a resist in an area to be further patterned is
 undesirable. Also, undesired residue between patterned features can have
 deleterious effects on subsequent film depositions processes, such as
 metallization, or cause undesirable surface states and charges leading to
 reduced device performance.
 Numerous polymer stripper compositions have been developed to remove
 positive and negative photoresists. For example, U.S. Pat. No. 5,962,197
 (Chen) discloses a composition for removing photoresists or soldermasks
 containing 30-80% by weight of a propylene glycol ether, 10-60% by weight
 of a pyrrolidone, 0.1-5% by weight of potassium hydroxide, 0.1-10% by
 weight of a surfactant, 0-20% by weight of 1,3-butanediol, 0-10% by weight
 of 2-(2-) aminoethoxy)ethanol and a water content of &lt;1%. Other
 compositions are known that contain amines, such as alkanolamines, or
 tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, as
 the active polymer removing agent. Surfactants may optionally be used in
 such compositions. See, for example, PCT patent application WO 88/05813
 (Martin et al.) which discloses a mixture having a selected solvent as the
 major component and a tetraalkylammonium hydroxide as a minor component
 and optionally a surfactant.
 The semiconductor industry is moving toward sub-quarter micron geometry
 features. As the geometry of the features gets smaller and pattern density
 increases, plasma etching, reactive ion etching, ion milling and the like
 are required for the lithographic process. During such plasma etching,
 reactive ion etching and ion milling processes, the polymeric material is
 subjected to conditions that make the removal of such polymeric material
 difficult. During the plasma etch process a photoresist film forms a hard
 to remove organometallic polymeric residue on the sidewalls of the various
 features being etched. Furthermore, the photoresist is extensively
 cross-linked due to the high vacuum and high temperature conditions in the
 etch chamber. Known cleaning processes do not acceptably remove such
 polymeric residue. For example, acetone or N-methylpyrrolidinone is
 currently used at extreme conditions, which include high temperature and
 extended cycle times. Such use conditions are often above the flashpoint
 of the solvent which raises certain environmental, health and safety
 issues regarding operator exposure. In addition, productivity and
 throughput are adversely affected by the extended process cycle times
 required. Even with such extreme stripping conditions, the devices may
 have to undergo wet strip followed by de-scum (O.sub.2 plasma ash) and a
 subsequent wet clean for a wet-dry-wet strip process.
 Known stripping compositions for post-plasma etch polymer removal
 applications have numerous drawbacks including, undesirable flammability,
 toxicity, volatility, odor, necessity for use at elevated temperatures
 such as up to 100.degree. C., and high cost due to handling regulated
 materials. A particular problem with advanced next generation
 semiconductor devices is that known stripping compositions are
 incompatible with a variety of thin films in such devices, that is, such
 known stripping compositions cause corrosion of the thin films,
 specifically copper, and low-k dielectric material present in such
 advanced devices.
 Methods for increasing the effectiveness of polymer removers have been
 proposed. For example, U.S. Pat. No. 4,786,578 (Neisius et al.) discloses
 a rinse solution used after a photoresist stripper. This rinse solution
 contains a nonionic surfactant and an organic base, such as an
 alkanolamine, that will form a water-soluble salt with
 alkylbenzenesulfonic acids. U.S. Pat. No. 4,824,762 (Kobayashi et al.)
 discloses a photoresist stripper post rinse containing a glycol ether and
 an aliphatic amine. In both patents, the compositions contain amines which
 tend to cause corrosion of copper present in the electronic devices. A
 pretreatment has been proposed using hot (110-125.degree. C.) solvent, see
 U.S. Pat. No. 4,202,703 (Zuber et al.). In this patent, the pretreatment
 was followed by a stripper containing a tetraalkylammonium hydroxide and
 then a post rinse with 1,1,1-trichloroethane. Such a process raises a
 number of environmental concerns.
 There is thus a continuing need to effectively remove polymeric material,
 including post plasma etch polymeric material, from electronic devices in
 ways that are environmentally compatible, that do not damage the features
 and geometries of the electronic devices, that do not cause corrosion of
 the substrate, particularly thin metal films, and that do not etch
 dielectric layers in the substrate.
 SUMMARY OF THE INVENTION
 It has been surprisingly found that polymeric material may be easily and
 cleanly removed from substrates, particularly 100% copper substrates with
 dielectric materials by first pretreating the polymeric material and then
 contacting the polymeric material with a stripping composition. Such
 polymeric material may be removed according to the present invention
 without corrosion of underlying metal layers, specifically copper, and
 without etching of conventional dielectric materials, such as silicon
 dioxide and low dielectric constant ("low k") materials.
 In one aspect, the present invention provides a composition for the
 pretreatment of polymeric material to be removed from a substrate
 including one or more polyol compounds, one or more glycol ethers, water
 and one or more surfactants, wherein the composition is substantially free
 of amines, alkanolamines, hydroxylamines, tetraalkylammonium hydroxides,
 ammonium bifluoride, ammonium-tetramethylammonium bifluoride, and alkali
 metal hydroxides.
 In a second aspect, the present invention provides a method of pretreating
 polymeric material to be removed from a substrate including the step of
 contacting a substrate containing polymeric material to be removed with
 the composition described above.
 In a third aspect, the present invention provides a method for preparing
 integrated circuits including one or more polymeric materials to be
 removed including the steps of: a) contacting the polymeric material with
 a pretreatment composition including one or more one or more polyol
 compounds, one or more glycol ethers, water and one or more surfactants
 for a period of time sufficient to pretreat the polymeric material; b)
 removing the polymeric material from contact with the pretreatment
 composition; and c) then contacting the polymeric material with a polymer
 stripping composition; wherein the pretreatment composition is
 substantially free of amines, alkanolamines, hydroxylamines,
 tetraalkylammonium hydroxides, ammonium bifluoride,
 ammonium-tetramethylammonium bifluoride, and alkali metal hydroxides.
 In a fourth aspect, the present invention provides a method for preparing
 magnetic thin film heads including the steps of: a) contacting a magnetic
 thin film head precursor containing a polymeric material to be removed
 with a pretreatment composition including one or more polyol compounds,
 one or more glycol ethers, water and one or more surfactants for a period
 of time sufficient to pretreat the polymeric material; b) removing the
 polymeric material from contact with the pretreatment composition; and c)
 then contacting the polymeric material with a polymer stripping
 composition, wherein the pretreatment composition is substantially free of
 amines, alkanolamines, hydroxylamines, tetraalkylammonium hydroxides,
 ammonium bifluoride, ammonium-tetramethylammonium bifluoride, and alkali
 metal hydroxides.
 DETAILED DESCRIPTION OF THE INVENTION
 As used throughout this specification, the following abbreviations shall
 have the following meanings unless the context clearly indicates
 otherwise: .degree. C.=degrees Centigrade; % wt=percent by weight;
 mL=milliliter; min=minute; DPM=dipropylene glycol monomethyl ether;
 DPNB=dipropylene glycol mono-n-butyl ether; and
 MP-diol=2-methyl-1,3-propanediol. All percentages are by weight. All
 numerical ranges are inclusive and combinable.
 The terms "stripping" and "removing" are used interchangeably throughout
 this specification. Likewise, the terms "stripper" and "remover" are used
 interchangeably. "Alkyl"refers to linear, branched and cyclic alkyl. The
 term "substituted alkyl" refers to an alkyl group having one or more of
 its hydrogens replaced with another substituent group, such as halogen,
 cyano, nitro, (C.sub.1 -C.sub.6)alkoxy, mercapto, (C.sub.1
 -C.sub.6)alkylthio, and the like. As used throughout this specification,
 the term "aprotic" refers to compounds that do not accept or yield a
 proton. The term "glycol" refers to dihydric alcohols. Thus, the term
 "glycol ether" refers to ethers of dihydric alcohols.
 Polymeric material on a substrate, including post plasma etch polymeric
 material, may be effectively removed by first treating or pretreating the
 polymeric material to be removed with the pretreatment composition
 according to the present invention. The polymeric material is then removed
 from contact with the pretreatment composition and then contacted with a
 polymer stripping composition. It is preferred that the substrate is not
 rinsed prior to the pretreatment step. It is further preferred that the
 polymeric material is not rinsed between the pretreating step and the
 polymer stripping step. Thus, the substrate containing the polymeric
 material is removed from contact with the pretreatment composition and
 directly contacted with a polymer stripping composition. Typically, the
 substrate is rinsed after the polymer stripping step.
 The compositions useful for pretreating polymeric material according to the
 present invention include one or more polyol compounds, one or more glycol
 ethers, water and one or more surfactants. Such pretreatment compositions
 are typically substantially free of polymer removing components, such as
 amines, alkanolamines, hydroxylamines, tetraalkylammonium hydroxides,
 ammonium bifluoride, ammonium-tetramethylammonium bifluoride, alkali metal
 hydroxides and the like. It is preferred that the pretreatment
 compositions of the present invention are free of amines, alkanolamines,
 hydroxylamines, tetraalkylammonium hydroxides, ammonium bifluoride,
 ammonium-tetramethylammonium bifluoride and lakali metal hydroxides.
 The polyol compounds useful in the present invention are any which are
 miscible with water and do not destabilize the composition. By the term
 "polyol compound" is meant a compound having two or more hydroxyl groups.
 Suitable polyol compounds include aliphatic polyol compounds such as
 (C.sub.2 -C.sub.20)alkanediols, substituted (C.sub.2
 -C.sub.20)alkanediols, (C.sub.2 -C.sub.20)alkanetriols, substituted
 (C.sub.2 -C.sub.20)alkanetriols, and the like. Suitable aliphatic polyol
 compounds include, but are not limited to, ethylene glycol, propylene
 glycol, diethylene glycol, dipropylene glycol, triethylene glycol,
 tripropylene glycol, 2-methyl-1,3-propanediol, butanediol, pentanediol,
 hexanediol, glycerol and the like. It is preferred that the aliphatic
 polyol compound is ethylene glycol, propylene glycol,
 2-methyl-propanediol, butanediol or pentanediol. Such polyol compounds are
 generally commercially available, such as from Aldrich (Milwaukee,
 Wisconsin), and may be used without further purification. The polyol
 compounds are typically used in the present invention in an amount in the
 range of from about 0.5 to about 20% wt based on the total weight of the
 composition, preferably from about 2 to about 10% wt, and more preferably
 from about 5 to about 6% wt.
 The glycol ethers useful in the present invention are any which are water
 miscible, compatible with the polyol compound and do not destabilize the
 composition such as glycol mono(C.sub.1 -C.sub.6)alkyl ethers and glycol
 di(C.sub.1 -C.sub.6)alkyl ethers, such as but not limited to (C.sub.1
 -C.sub.20)alkanediol (C.sub.1 -C.sub.6)alkyl ethers and (C.sub.1
 -C.sub.20)alkanediol di(C.sub.1 -C.sub.6)alkyl ethers. Suitable glycol
 ethers include, but are not limited to, ethylene glycol monomethyl ether,
 diethylene glycol monomethyl ether, propylene glycol monomethyl ether,
 propylene glycol dimethyl ether, propylene glycol mono-n-butyl ether,
 dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether,
 dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl
 ether, and the like. It is preferred that the glycol ether is dipropylene
 glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene
 glycol mono-n-butyl ether or dipropylene glycol mono-n-butyl ether. Such
 glycol ethers are generally commercially available and may be used without
 further purification. Typically, the glycol ethers are present in the
 compositions of the invention in an amount in the range of from about 0.5
 to about 20% wt based on the total weight of the composition, and
 preferably from about 5 to about 10% wt.
 Nonionic, anionic, cationic and amphoteric surfactants may be used in the
 compositions of the present invention. Nonionic surfactants are preferred.
 Such surfactants are generally commercially available. Useful nonionic
 surfactants include, but are not limited to, ethoxylated alkylphenols,
 fatty acid ethoxylates, fatty alcohol ethoxylates, ethylene
 oxide/propylene oxide ("EO/PO") condensates, and the like. Suitable
 ethoxylated alkylphenols include ethoxylation products of (C.sub.6
 -C.sub.14)alkylphenols, that is alkylphenols having 6 to 14 carbon atoms
 in the alkyl chain, and a degree of ethoxylation of 2 to 20. Fatty acids
 or fatty alcohol ethoxylates with saturated or unsaturated hydrocarbon
 chains having 8 to 24 carbon atoms and a degree of ethoxylation of 2 to 20
 are also suitable. Particularly suitable EO/PO condensates are those
 having about 10 to about 20 EO or PO units.
 The surfactants are typically present in an amount of from about 0.1 to
 about 10% wt, preferably from about 0.5 to about 2% wt, and more
 preferably from about 1 to about 1.5% wt, based on the total weight of the
 composition.
 Typically, deionized water is used in the present invention. Water is
 present in an amount sufficient to make up 100% wt, based on the total
 weight of the composition. Typically, the amount of water is from about 50
 to about 98.9% wt based on the total weight of the composition, and
 preferably from about 75 to about 95% wt.
 The pretreatment compositions of the present invention may optionally
 include one or more additives. Suitable additives include, but are not
 limited to, corrosion inhibitors, wetting agents, co-solvents, chelating
 agents and the like.
 Any corrosion inhibitor which reduces the corrosion of metal film layers is
 suitable for use in the present invention. Suitable corrosion inhibitors
 include, but are not limited to, catechol; (C.sub.1 -C.sub.6)alkylcatechol
 such as methylcatechol, ethylcatechol and tert-butylcatechol;
 benzotriazole; hydroxyanisole; (C.sub.1 -C.sub.10)alkylbenzotriazoles;
 (C.sub.1 -C.sub.10)hydroxyalkylbenzotriazoles; 2-mercaptobenimidazole;
 gallic acid; gallic acid esters such as methyl gallate and propyl gallate;
 and the like. It is preferred that the corrosion inhibitor is catechol,
 (C.sub.1 -C.sub.6)alkylcatechol, benzotriazole or (C.sub.1
 -C.sub.10)alkylbenzotriazoles, 2-mercaptobenimidazole, and more preferably
 benzotriazole and tert-butylcatechol. Such corrosion inhibitors are
 generally commercially available from a variety of sources, such as
 Aldrich (Milwaukee, Wis.) and may be used without further purification.
 When such corrosion inhibitors are used in the compositions of the present
 invention, they are typically present in an amount in the range of from
 about 0.01 to about 10% wt, based on the total weight of the composition.
 It is preferred that the amount of corrosion inhibitor is from about 0.2
 to about 5% wt, more preferably about 0.5 to about 3% wt, and most
 preferably from about 1.5 to about 2.5% wt. It is preferred that a
 corrosion inhibitor is used.
 Suitable cosolvents useful in the compositions are any which are water
 miscible and do not destabilize the present compositions. Such suitable
 cosolvents include, but are not limited to, polar aprotic solvents such as
 dimethyl sulfoxide, tetramethylene sulfone (or sulfolane), and dimethyl
 sufur dioxide; aminoalcohols such as aminoethylaminoethanol; N-(C.sub.1
 -C.sub.10)alkylpyrrolidones such as N-methylpyrrolidone ("NMP"),
 N-ethylpyrrolidone, N-hydroxyethylpyrrolidone and N-cyclohexylpyrrolidone;
 amides such as dimethylacetamide ("DMAC") and the like. It is preferred
 that the cosolvent is selected from N-(C.sub.1 -C.sub.10)alkylpyrrolidones
 and amides, more preferably N-methylpyrrolidone, N-ethylpyrrolidone,
 N-hydroxyethylpyrrolidone, N-cyclohexylpyrrolidone and dimethylacetamide.
 It is further preferred that the compositions of the present invention are
 free of amine cosolvent, such as aminoalcohols. When such cosolvents are
 used they are typically present in an amount in the range of about 0.1 to
 about 20% wt, based on the total weight of the composition, preferably
 about 1 to about 10% wt, and more preferably from about 1 to about 5% wt.
 The compositions of the present invention may be prepared by combining the
 one or more polyol compounds, one or more glycol ethers, water, one or
 more surfactants and optionally one or more additives in any order.
 The compositions of the present invention are suitable for pretreating
 polymeric material to be removed from a substrate. The removal of any
 polymeric material, such as, but not limited to, photoresists,
 soldermasks, antireflective coatings, and the like, including such
 polymeric material that has been subjected to harsh process conditions
 such as plasma etching, auto-plasma ashing, ion implantation or ion
 milling processes, can be effectively enhanced by first contacting it with
 the pretreatment compositions of the present invention and then contacting
 it with known polymer stripping compositions. Any polymeric material
 subjected to the harsh treatment processes described above is referred to
 as "post-plasma etch polymeric residue" throughout this specification. The
 compositions and methods of the present invention are particularly useful
 in aiding removal of the organometallic polymeric residue present after a
 dry plasma etching, reactive ion etching and ion milling of materials,
 such as photoresists, conducting metal layers and insulating dielectric
 layers.
 Polymeric residue on a substrate may be removed by first contacting the
 substrate with a composition of the present invention for a period of time
 sufficient to pretreat the polymeric material. The substrate may be
 contacted with the compositions of the present invention by any known
 means, such as immersion of the substrate in a bath, such as a wet
 chemical bench, containing a composition of the present invention such
 bath being at room temperature or heated, or by spraying a composition of
 the present invention at a desired temperature on the surface of the
 substrate. Typically, the polymeric material is contacted with the
 pretreatment compositions of the present invention for up to 30 minutes,
 preferably up to 20 minutes, and more preferably up to 15 minutes.
 Typically, polymeric material is pretreated with the compositions of the
 present invention from about 5 to about 15 minutes.
 The pretreatment compositions of the present invention may be effectively
 used at a wide range of temperatures, such as but not limited to, up to
 about 60.degree. C., preferably from about 20.degree. C. to about
 50.degree. C., more preferably from about 23.degree. C. to about
 45.degree. C., and most preferably from about 25.degree. C. to about
 35.degree. C. An advantage of the pretreatment compositions is that they
 may be effectively used at ambient temperature.
 Following contact with the compositions of the present invention, the
 substrate is then contacted with known polymer stripping compositions. The
 substrate may be contacted with the polymer stripping compositions by any
 known manner, such as immersion of the substrate in a bath, such as a wet
 chemical bench, containing the polymer stripping composition or by
 spraying a polymer stripping composition on the surface of the substrate.
 Any polymer stripping compositions may be advantageously used with the
 pretreatment compositions of the present invention. It is preferred that
 the polymer stripping compositions include one or more of one or more
 polyol compounds, one or more glycol ethers and water. The polymer
 stripping compositions typically contain one or more polymer removing
 components, such as but not limited to amines, alkanolamines,
 hydroxylamines, tetraalkylammonium hydroxides, ammonium bifluoride,
 ammonium-tetramethylammonium bifluoride, and the like. It is further
 preferred that the polymer removing agent is one or more of
 hydroxylamines, tetraalkylammonium hydroxides, ammonium bifluoride, and
 ammonium-tetramethylammonium bifluoride. Such polymer stripping
 compositions are generally well known and commercially available. Suitable
 polymer stripping compositions include those sold under the tradenames
 ACT-935 (available from Ashland), EKC-265 (available from EKC Technology,
 Hayward, Calif.), PRX-407 and PRX-120 (both available from Shipley
 Company.backslash.Silicon Valley Chemlabs, Sunnyvale, Calif.).
 No special procedures are necessary for using the polymer stripping
 compositions following pretreatment of polymeric material with the
 compositions of the present invention. The polymer stripping compositions
 are typically used in the manner recommended by the manufacturer. Such
 polymer stripping compositions may be used at ambient temperature or may
 be heated.
 It is preferred that the substrate is not rinsed until after the polymeric
 material has been subjected to the polymer stripping compositions.
 Following contact with the polymer stripping compositions, the substrate
 is typically rinsed such as with deionized water, and then dried such as
 by spin drying.
 An advantage of the pretreatment of the present invention is that polymeric
 material may be effectively removed in less time as compared to the time
 required to remove such polymeric material without pretreatment. Thus, the
 time required for contact with polymer stripping compositions is reduced.
 By reducing the time a substrate is in contact with the harsh components
 of a polymer stripping composition, adverse effects on the substrate, such
 as corrosion and lifting of layers, are also reduced.
 A further advantage of the compositions of the present invention is that
 they may be effectively used to pretreat polymeric material on substrates
 including one or more dielectric layers. Such pretreatment allows faster
 removal of the polymeric material when contacted with a polymer stripping
 composition. By increasing the rate of polymer removal, the substrate is
 exposed to the stripping composition for a shorter period of time and thus
 etching of the dielectric material is substantially reduced.
 A still further advantage of the compositions of the present invention is
 that post-plasma etch polymeric material may be removed from a substrate
 such that etching of thermal oxide layers underneath metal lines is
 greatly reduced or eliminated.
 The compositions of the present invention are particularly useful in aiding
 removal of post plasma etch residues when conventional strippers are not
 capable of removing such residues. Furthermore the present pretreatment
 compositions are substantially non-corrosive to substrates containing
 metals, particularly copper and aluminum. It is preferred that the
 compositions of the present invention are non-corrosive to metals,
 particularly copper and aluminum.
 Thus, the compositions of the present invention are useful in pretreating
 any polymeric material that needs to be removed during the manufacture of
 electronic devices, such as, but not limited to, flat panel display
 TFT/LCD manufacture, magneto-resistive and giant magnetoresistive thin
 film head manufacture, or read-write device manufacture. The compositions
 of the present invention are substantially inert, and preferably
 completely inert, to the metal films used in magneto-resistive and giant
 magneto-resistive thin film head manufacture such as, but not limited to,
 aluminum oxide ("Al.sub.2 O.sub.3 "), gold ("Au"), cobalt ("Co"), copper
 ("Cu"), iron ("Fe"), iridium ("Ir"), manganese ("Mn"), molybdenum ("Mo"),
 nickel ("Ni"), platinum ("Pt"), ruthenium ("Ru"), and zirconium ("Zr"), as
 well as other metals used in the manufacture of semiconductors and
 electronic materials, such as, but not limited to, copper, aluminum,
 nickel-iron, tungsten, titanium, titanium-nitride, tantalum, tantalum
 nitride.

The following examples are intended to illustrate further various aspects
 of the present invention, but are not intended to limit the scope of the
 invention in any aspect.
 EXAMPLE 1
 A pre-treatment solution was prepared by combining 5% MP-diol, 1% Japanese
 soap (a nonionic surfactant), 5% DPM with the balance being de-ionized
 ("DI") water.
 EXAMPLE 2
 A wafer containing sub-micron dual damascene vias to a copper metal layer
 and post plasma etched polymeric residue was examined by SEM which showed
 heavy polymer on the via bottoms as well as some sidewall polymer. The
 wafer was contacted with the solution of Example 1 (pretreated) for 1
 minute at 23.degree. C., removed from contact with the solution and placed
 in a polymer stripper (remover) bath containing 13% dimethylacetamide, 27%
 DPM, 28% DI water, and 28% MP-diol as active ingredients at 23.degree. C.
 for 10 minutes. The wafer was then removed from the stripping bath, rinsed
 for 5 minutes with the solution from Example 1 for 5 minutes, rinsed with
 DI water for 2 minutes and then dried. SEM analysis showed the wafer to be
 clean with no polymer in the bottom of the vias and no sidewall polymer
 remaining.
 EXAMPLE 3 (Comparative)
 The procedure of Example 2 was repeated except that the wafer was first
 contacted with the polymer remover bath for 30 minutes at 23.degree. C.
 The wafer was removed from the bath and placed in a bath containing the
 solution from Example 1 for 15 minutes. After removal from the bath, the
 wafer was then rinsed with DI water for 5 minutes and dried. SEM analysis
 showed the wafer to be mostly clean with polymer still remaining in the
 bottoms of the vias.
 EXAMPLE 4
 A wafer containing sub-micron vias to an aluminum metal layer and post
 plasma etched polymeric residue was examined by SEM which showed heavy
 polymer on the via sidewalls. The wafer was contacted with the solution of
 Example 1 (pretreated) for 1 minute at 23.degree. C., removed from contact
 with the solution and placed in the polymer stripper (remover) bath of
 Example 2 at 23.degree. C. for 10 minutes. The wafer was then removed from
 the stripping bath, rinsed for 5 minutes with the solution from Example 1
 for 5 minutes, rinsed with DI water for 5 minutes and then dried. SEM
 analysis showed the wafer to be clean with no sidewall polymer remaining.
 EXAMPLE 5
 The procedure of Example 4 was repeated except that the wafer was not
 subjected to a pretreatment step. After contact with the polymer stripping
 bath, the wafer was then rinsed with DI water for 5 minutes and dried. SEM
 analysis showed some sidewall polymer remaining.
 EXAMPLE 6
 A wafer containing post plasma etch sidewall polymer residue was contacted
 with the solution of Example 1 for 30 minutes at 23.degree. C. After
 removing the wafer from contact with the solution, the wafer was rinsed
 with DI water for 5 minutes and dried. SEM analysis of the wafer showed
 that the solution of Example 1 by itself was ineffective in removing post
 plasma etch sidewall polymer.
 The above examples clearly show that the solutions of the present invention
 are effective in pretreating substrates containing polymeric residue to be
 removed. Such pretreatment results in shorter contact time of the
 substrates with the polymer stripping baths as well as more complete
 removal of polymeric material, particularly post plasma etch polymeric
 material.