Metal-safe solid form aqueous-based compositions and methods to remove polymeric materials in electronics manufacturing

Abstract

Compositions and methods useful for the removal of organic substances from substrates, for example, electronic device substrates, are provided. A method is presented which uses a minimum amount of solid form concentrate that is diluted into water, introduced into a manufacturing tool and heated, applied to said substrate for a sufficient time to allow penetration and removal of an organic substance, and immediately rinsed with water to achieve complete removal. These compositions and methods are particularly suitable for removing and completely dissolving photoresists of the positive variety most commonly used in the manufacture of a flat panel display (FPD) and other electronic substrates.

Claims

1. A solid form composition used in electronic applications as a solid form concentrate to prepare aqueous alkaline solutions of pH 10 or above for removing photoresists from inorganic substrates comprising: a metal safe inhibitor comprising an inorganic silicate (Component A); an alkali hydroxide agent (Component B) that exhibits a dissociation constant of 110.sup.3 (pK.sub.b3); and, a fluorocarbon surfactant (component C); wherein the ratio of the respective weight percent values of Component A and Component B as (A wt %)/(B wt %) varies between 0.2 to 10 and the collective sum weight percent of Component A and Component B varies from 10 wt % to about 90 wt %.

2. The solid form composition of claim 1, wherein Component A further comprises one or more compounds selected from benzylic hydroxides catechol, triazoles, benzotriazole, tolytriazole, imidazoles, borates, thiourea, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitrilotriacetic acid, 2,4-pentanedione, reducing sugars, hydroquinones, glyoxal, salicylaldehyde, citric acid or salts thereof, ascorbic acid or salts thereof, hydroxylamines, rosin acids, or vanillin.

3. The solid form composition of claim 1 wherein the alkali hydroxide agent has the formula M(OH).sub.n where M is Na, K, Li, Cs, Rb, Ca, Mg, Sr, or Ba, and n is 1 or 2; or the alkali hydroxide agent has the formula (R).sub.4N.sup.+OH.sup. wherein each R group is (CH.sub.3); each R group is (CH.sub.2CH.sub.3); each R group is (CH.sub.2CH.sub.2CH.sub.3).sub.4; or one R group is (C.sub.6H.sub.5) and the remaining three R groups are (CH.sub.3).

4. The solid form composition of claim 1 wherein Component A further comprises a film forming polymer.

5. The solid form composition of claim 1 wherein Component B is KOH.

6. The solid form composition of claim 1 wherein Component B is LiOH.

7. The solid form composition of claim 1 wherein Component C further comprises an amine.

8. The solid form composition of claim 1 wherein Component C further comprises a water soluble polymer.

9. A method for removing photoresists from inorganic substrates, said method comprising mixing the composition of claim 1 with deionized water to form a solution, contacting the inorganic substrate with the solution at a temperature of between 40-90 degrees Celsius to remove said photoresist, and rinsing the inorganic substrate with water.

10. The method of claim 9 wherein said photoresists are removed from semiconductors or electronic displays.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The present invention provides a metal-safe aqueous stripping composition, which exists in a physical solid form prior to dilution and preparation, and methods of use to quickly and effectively remove polymeric organic substances from inorganic substrates such as those used to manufacture electronics. The stripping composition comprises a blend of chemistries to include an inhibitor or mixture thereof defined as a protecting agent, an alkaline agent that exhibits an aqueous base dissociation constant of 110.sup.3 (pK.sub.b3), and one or more additives consisting of surfactants and water soluble polymers, which effectively removes photoresist mask and its residue while achieving innumerable benefits in the fabrication of microcircuits.

(2) The invention is an aqueous-based system designed to remove resists and residue that is in profound contrast to the current use of organic solvents for the same purpose. Organic solvent stripping of resists and residue, albeit a standard practice in the industry, is the very condition of this invention's baseline comparison, whereby numerous benefits to lower cost and improve safety help to define its novelty and unique practice. The benefits of this invention exceed the obvious benefits of low-cost when considering only the raw materials. For example, a typical end-use concentration mixture of the invention is between 2-5% (wt %) of the collective solid-form mixture added to DI water. In other words, 95-98% DI water combines with the invention's final mixture at the point of use. All microelectronic fabrication facilities have direct access to DI water measured in mass quantities every day during the manufacturing of their product. Because of its ubiquitous nature and availability, DI water is often considered to be an insignificant cost to the facility as compared with the use of organic solvents. For these reasons and others, the use of DI water to clean parts is an accepted practice and viewed as safe and low cost for both the workers and the final product.

(3) Alternatively, the use of organic solvents requires a raw material not directly available to the fabrication facility, most commonly this is a blend of materials, and is provided by external suppliers. Depending upon the organic mixture, the components may trigger certain hazardous criteria as toxicity and flammability, requiring their permitting for use in the facility at a given risk to workers and operating cost within the tool. For example, it is known that certain businesses that manufacture FPDs use large quantities as measured in metric tons of n,n-dimethylacetamide (DMAC, CAS #127-19-5), however, the product is considered a developmental toxin by the USEPA issue in May of 2010 of the safe drinking water standard (1986, Proposition 65). Although DMAC may be an excellent solvent for polymeric substances, its use in large volumes within enclosed fabrication facilities presents a health and safety risk to workers. Further, the solvent must be also reviewed and tested for its compatibility in the moving parts of the tool and filtration system. Upon completing a risk review for health and safety and tool compatibility, the organic solvent is permitted and approved for use. The solvent system must be purchased, inspected, shipped, stored, used, inspected repeatedly at numerous times during its use, and ultimately collected as a waste material, stored again into separate containers, and shipped off-site for recycle to be considered later for re-introduction into the process.

(4) When the use of the invention is compared with organic solvents, and it is known that 95% of DI water is mixed with the invention to prepare a metal-safe resist and residue stripper, the contrast becomes a comparison between DI water and organic solvents. Because DI water is readily available at the fabrication facility, there are significant benefits in reducing the cost of raw materials, storage space, health and safety risk, and waste generation. Promoting the use of DI water over organic solvents is also preferred for substrate and tool compatibility. As the manufacture of FPDs consider flexible thin organic substrates, compatibility is generally improved with chemistries based upon DI water as compared to organic solvents. Further, the periodic addition of concentrated chemistries to DI water for cleaning will allow the working life of the system to be increased far greater than is possible with organic solvents which are unable to incur the same adjustment practice. It is the objective of this invention, it's novelty, and unique design, to promote aqueous chemistries as solid-form concentrates while being used in DI water dilution that provides maximum flexibility to the manufacturing facility.

(5) Upon application of the invention in the end-use form of the aqueous alkaline mixture to contact the resist polymeric framework, the polymer breaks down, allowing the disintegrated residue to be rinsed away with water. The removal rates will, of course, vary depending upon the thickness of the resist coating and the condition to which the coating was exposed during the process. Heating assists in facilitating the removal and dissolution of resist and residue.

(6) As is the case with many manufacturers of FPDs and other electronics, the resist choice is positive-tone, typically a novolac variety. Without wishing to be bound by any particular theory, it is believed that the alkali component of the invention penetrates the void space of the resist polymer and dissolves non-crosslinked novolac. These cresol and cresol-formaldehyde based resins (e.g. novolac) exhibit at least one free alcohol (e.g. OH) functional group and are readily soluble in alkaline systems. In fact, this represents a fundamental formulation design for development of the positive-tone resist, whereby its solubility is governed by the unexposed form of the photoinitiator, diazonapthaquinone (DNQ). In the unexposed condition, DNQ is hydrophobic and renders the resist resin insoluble based upon its dispersion throughout the matrix. However, once exposed, the DNQ molecule changes to a ketene, which in the presence of moisture, converts to a carboxylic acid. Therefore, resist removal occurs rapidly based upon the existing resin aqueous alkali solubility and the effects of dispersed DNQ acidity to accelerate its breakdown. Throughout the surface of a FPD, resist removal may occur at slightly different rates based upon the chemistry to penetrate into the top skin of the resist, diffusion into the underlying resin, and release of underlying pieces to the bulk stripper followed by exposure of the underlying material.

(7) The resist dissolution process described here is typically conducted in a tool where the chemistry is heated and sprayed onto the surface, a physical process that is considered to be aggressive. To afford protection for transition metals such as copper and aluminum, a suitable inhibitor or protecting agent is chosen that comprises a silicate, combined with a triazole, a citrate, and possibly a film forming agent such as polyvinylpyrrolidone. Silicates most commercially available include sodium, potassium, and lithium based, however, the sodium versions are discouraged for electronics applications due to their propinquity to penetrate the substrate and cause electromigration issues. The preferred inhibitor ingredients include a silicate of the trade name identity, KASOLV 16 (PQ Corporation), which may be used singularly or be mixed with one or more of the following: a conventional triazole as BTA (benzyltriazole), TTA (tolytriazole), MBTA (mercaptobenzyltriazole), citrates may be included as tribasic potassium citrate (C.sub.6H.sub.5K.sub.3O.sub.7), a rosin acid of the trade name identity, JONCRYL 682 (BASF Corporation), and a film-former as PVP K-series (International Specialty Products, ISP), where K varies from 15-120 (MW 6,000-3 m). The inhibitor package may exist as combinations thereof, incorporated into the stripper composition.

(8) The alkali agent of the invention is desired to be highly dissociative in water to achieve maximum strength when diluted in DI water, preferred to exhibit a dissociation constant of 110.sup.3 (pK.sub.b3), and most preferred 110.sup.2 (pK.sub.b2). The alkali agent may exist singularly or in a mixture which comprises the molecular form, excluding water of hydration within the complex: M.sub.nO (oxide), MOH (hydroxide), M.sub.yCO.sub.3 (carbonate), M.sub.y(PO.sub.4).sub.z (phosphate), MOC(CH.sub.3).sub.3 (butyrate or butoxide), where M may exist as Na, K, Li, Cs, Rb, Ca, Mg, Sr, Ba and n may be 1, 2, or 3 and m may be 1 or 2 and the alkali agent may also exist as RNOH where R may be (CH.sub.3).sub.4, (CH.sub.2CH.sub.3).sub.4, (CH.sub.2CH.sub.2CH.sub.3).sub.4, or (C.sub.6H.sub.6)(CH.sub.3).sub.3, the preferred alkali is KOH or LiOH and the most preferred is a combination of KOH and LiOH.

(9) The total amount of inhibitor (identified as (a)) in the invention is present at a level relative to the amount of alkali agent (identified as (b)), the weight percent (wt %) ratio of inhibitor relative to alkali ((a)/(b)) varies from an equal amount ((a)/(b)=1) to a level that is greater than the alkali level by a factor of 10 ((a)/(b)=10), and the sum total weight percent (wt %) of alkali and inhibitor present in the inhibitor varies from 10 wt % to about 99.9 wt %, and preferable of the order of about 50 to about 85 wt % is sufficient.

(10) To effect small geometry penetration and prevention of redeposit or scale formation from premature drying of the stripper prior to rinsing, the stripping compositions also comprise surfactants, water soluble polymers and other additives. These items ensure the stripper functions properly while resist is loaded into the chemistry to discourage residue formation with more solids dispersed into solution. The additives may be derived from, but not limited to, surfactants such as nonionic alcohol ethoxylates nonyl-phenols and nonyl-ethoxylates with a HLB (hydrophilic/lipophilic balance) ranging from 7-15, anionic forms that include alkyl-sulfonates, phosphate esters, and succinates, and fluorinated systems, bisphenol ethoxylates and propoxylates, alkylbenzene salts, cellulose acetate phthalate, cellulosic derivatives of alkoxyethyl and hydroxypropyl, copolymers of ethylene and propylene oxide, dendritic polyesters, ethoxylated amines, ethoxylated alcohol salts, ethylene acrylic acid, hydroxy-methacrylates, phosphate esters, polyethylene glycols, polyethylene imine, polyethylene oxides, polyvinyl alcohol, polyvinyl pyrollidinone, starch, styrene maleic anhydride, sulfonated acrylics, sulfonated polystyrenes, sulfopolyester of the linear or branched formula, or rosin acids. These additives may be used singularly or in combinations thereof with the inhibitor protectant and alkali agent at weight percent levels varying from 0.1 wt % to about 90 wt %, and preferable of the order of about 15 wt % to about 50 wt % is sufficient.

(11) The temperature employed for suitable performance is dependent upon the resist processing conditions. In most cases, the temperature in the range from about 20 C. (room temperature) to about 80 C. is effective for proper operation of the aqueous stripping compositions of the present invention. Processing conditions may require using a temperature in excess of about 40 C., especially where the removal of more than one substance is desired such as the simultaneous stripping of a resist mask and sidewall polymer. When operated under the conditions stated within the customer's tool, the stripping composition quickly and effectively removes organic polymers from metallized and metallic surfaces.

(12) The disclosed invention differs from conventional organic solvent stripping processes in that it is an aqueous soluble system that is either comprising solid-form ingredients or collectively the final composition is of a physical solid form. It is therefore this solid-form aqueous resist stripper described here which provides the key novelty behind this invention and delivers several benefits in the manufacture of electronics. Such benefits begin with the extreme concentrated nature of the invention to minimize shipping costs, reduce storage space, improve worker safety, and eliminate wastes. The invention provides a broad improvement to performance and responsible care in the industry. To this end, the novelty and unique nature of this invention is considered a significant milestone in the elimination of organic solvents.

(13) In employing the stripping solutions of this invention, the electronics substrate covered with the baked resist and residue is brought into contact with the stripping solution usually within a conveyor operated tool moving from one chamber to another where a spray apparatus exists to deliver the invention stripper that has been prepared by dilution into DI water and heated to a temperature of between 40-90 C., preferably 60-70 C. Times required for stripping the resist vary to quite an extent depending on the resist type, thickness, and exposure condition, but for common positive-tone systems of <2 microns (um) and baking of 100 C., the times range from 15-60 seconds per stripping chamber for a triple chamber (3 chamber) tool. Generally, the time involved will be less than 1 minute during optimized performance conditions, while some resist, may require longer times where lower processing temperatures of the invention stripper are employed on highly polymerized and metallized surfaces. It will be appreciated that while many resists are completely dissolved from the substrate, others may be loosened, floated off, and subsequently dissolved in the bulk stripping composition.

(14) In the cases outlined here and without wishing to be bound by any particular theory, it is believed that the metal safe composition performs by the alkali component penetrating the void space of the resist organic layer and reacting with the underlying material to effect dissolution. In the case of cresol and cresol-formaldehyde based resins (e.g. novolac) the alcohol functional groups (e.g. OH) are readily able to react with the alkali to become soluble in the aqueous matrix and be emulsified, where it is then maintained in suspension by the water soluble polymer.

(15) Once the unbound resins of the resist begin to leach out, additional aqueous alkali agent diffuses into these areas and continues the same cycle. This process rapidly proceeds, typically on the order of seconds, and results in the resist pattern exhibiting a loss of adhesion to the substrate. The residual underlying organic substance migrates to the bulk stripper media where additional surface area is exposed and the solvation process described herein continues in an accelerated manner. By this time, the resist mask and residue has been in direct contact with the stripper composition and is lifted from the substrate and surrounded by other active alkali agent to effect further emulsifying and diffusing practice to occur until a completely dissolved state is achieved. Rinsing with DI water will immediately follow.

EXAMPLES

(16) The compositions of the invention and the method of making of the examples are described. It is understood, however, that the invention is not meant to be limited to the details described therein. In the examples, the percentages provided are percent (%) by weight unless otherwise stated.

(17) The invention is further illustrated, without limitation, by the following examples. The measurement of performance and selectivity of the invention is conducted using practices readily accepted by the industry. In such cases, measurement is made by optical microscope, etch rate determinations by high sensitivity gravimetric tests on metallic substrates, and where necessary, more detailed studies by using scanning electron microscopy (SEM).

(18) In the following examples, silicon wafers are used as the inorganic substrate upon which the organic substance is applied and cured. This material forms the basis for the survey, which the invention is demonstrated.

(19) Where applicable, the organic substance is applied in the manner of a coating utilizing a Brewer Science, Inc. CB-100 coater and following standard protocol for applying the liquid form of the polymer material (organic substance) to the said inorganic substrate. Once the material is coated, it is sent to a soft bake step on a hot plate at a defined temperature and time period. The positive photoresist used for demonstration is of the variety AZ-4620 (novolak based), manufactured by AZ Electronic Materials (AZEM), located in Branchburg N.J. (USA, www.azem.com). Where applicable, the material is exposed to ultraviolet light (UV) of a broad-band type emitting at 365 nm and of a high exposure dose of 0.12 W/cm2-sec, for a period up to 30 min.

Example #1

(20) The following example demonstrates the dependence of the resist removal performance on the pK.sub.b.value of the active agent prepared to a given concentration in water. Further, this example presents the difficulty in removing resists which have been subsequently baked to higher temperatures.

(21) Coated silicon wafers with AZ-4620 PR are prepared (6 Si), coat 1000 rpm 60 sec 6-8 ml, soft bake cure at 90-100 C, 5 min, reserve for post-bake as described: wafers #1-3, no post bake, wafers #4-6, post bake 130-140 C, 15 min, wafers #7-10, post bake 160-180 C, 15 min. Expose to the following solutions at three (3) different temperatures (room temperature20 C, 50 C, and 90 C). The active agent solutions are described as follows: tetramethylammonium hydroxide (TMAH, CAS #75-59-2, available from Sigma Aldrich) 0.26N, 95 g of 25% TMAH solution, dilute to 1 L with H2O; potassium hydroxide (KOH, CAS #1310-58-3, available from Sigma Aldrich) 0.26N, 14.6 g of 45% KOH solution, dilute to 1 L with H2O; sodium hydroxide (NaOH, CAS #1310-73-2, available from Sigma Aldrich) 0.26N, 23.1 g NaOH pellets, dilute to 1 L with H2O; diisopropylamine (DIPA, CAS #108-18-9, available from DOW Chemical) 0.26N, 34.1 g DIPA solid, dilute to 1 L with H2O; triisopropanolamine (TIPA, CAS #122-20-3, available from DOW Chemical) 0.26N, 49.7 g TIPA solid, dilute to 1 L with H2O.

(22) The pK.sub.b values of the active agents are found by using the equation pK.sub.a+pK.sub.b=14. The values of pK.sub.a are found in the literature and converted to pK.sub.b. The resist removal time of each chemistry segregated according to the resist hard bake condition (i.e. no hard bake, 130-140 C (135 C) 15 min, and 160-180 C (170 C) 15 min is given in Tables 1-3, where each table represents the removal condition temperature.

(23) TABLE-US-00001 TABLE 1 Resist (PR) removal time (cleaning) in varying chemistries with stated Pk.sub.b value based on the equation pK.sub.a + pK.sub.b = 14, operated at room temperature (20 C.) of resist exposed to specific hard bake (HB) conditions. Removal (min) Removal (min) Active Removal (min) HB 135 C. HB 170 C. Agent Pk.sub.a pK.sub.b No Hard Bake 15 min 15 min TMAH >13 <1 No clean No clean No clean KOH >13 <1 No clean No clean No clean NaOH >13 <1 1 min 1 min 1 min DIPA 8 6 No clean No clean No clean TIPA 9 5 No clean No clean No clean

(24) TABLE-US-00002 TABLE 2 Resist (PR) removal time (cleaning) in varying chemistries with stated Pk.sub.b value, operated at 50 C. of resist exposed to specific hard bake (HB) conditions. 50 C. PR 50 C. 50 C. PR Removal (min) Removal (min) Active removal (min) HB 135 C. HB 170 C. Agent pK.sub.b No Hard Bake 15 min 15 min TMAH <1 No clean No clean No clean KOH <1 5 min No clean No clean NaOH <1 <1 min <1 min <1 min DIPA 6 No clean No clean No clean TIPA 5 No clean No clean No clean

(25) TABLE-US-00003 TABLE 3 Resist (PR) removal time (cleaning) in varying chemistries with stated Pk.sub.b value, operated at 90 C. of resist exposed to specific hard bake (HB) conditions. 90 C. PR 90 C. 90 C. PR Removal (min) Removal (min) Active removal (min) HB 135 C. HB 170 C. Agent pK.sub.b No Hard Bake 15 min 15 min TMAH <1 1 min 3 min No clean KOH <1 <1 min 1 min 1 min NaOH <1 <1 min <1 min <1 min DIPA 6 3 min No clean No clean TIPA 5 No clean No clean No clean

Example #2

(26) The following example demonstrates the dependence of metal safety as moles of inhibitor (M.sub.i), moles of active agent (M.sub.a), expressed as the ratio (M.sub.i/M.sub.a) and represented numerically prepared as 5% (wt %) in water. In this case, the chosen inhibitor is an alkali silicate of the form potassium silicate (KASOLV 16, a powder with 53% SiO.sub.2 (wt %), PQ Corporation). The respective silicate is a solid form material with protective quality dependent upon the silicon dioxide content (wt % SiO.sub.2). Aluminum is tested for metal safety by immersion methods at temperatures of approximately 90 degrees centigrade. Aluminum metal is used as foil (aluminum foil, Reynolds Heavy-Duty, domestically available). Metal safety is measured using the observation of bubbles during immersion, the condition of the foil following exposure, and using a measured difference in the gravimetric weight of the specimens before and after their exposure. Gravimetric test results convert mass change into etch rate as angstroms/min. The following equation is used for this conversion: R=[W10^8]/[DT(2A)], where R=etch rate as angstroms/min, W is the mass difference in grams, D=density of the metal (aluminum=2.6989 g/cm.sup.3), T=time (min), and A=area of the aluminum foil in cm.sup.2. The results of observations for these tests are shown in Table 4, and gravimetric measurement in Table 5.

(27) TABLE-US-00004 TABLE 4 Observation of metal safety tests with aluminum foil used in 5% (w/w %) of varying mole ratio solutions of silicate inhibitor to active agent as KOH, expressed as (M.sub.i/M.sub.a). Solutions are tested at 90 C. for 20 min. Observations as solution bubbling and metal appearance following exposure. KASOLV 16, 0.00 0.32 0.42 0.47 moles as M.sub.i KOH, moles as M.sub.a 0.80 0.50 0.29 0.19 Mole ratio - 0 - 0.60 1.50 2.40 KASOLV16/KOH (M.sub.i/M.sub.a) Solution observations Extreme Vigorous Minor No during test (metal foil) vigorous bubbling bubbling bubbling bubbling Metal foil appearance Com- Etched Partial No effect, after exposure pletely (attacked) etch bright, dissolved (some shiny damage)

(28) TABLE-US-00005 TABLE 5 Metal safety tests in 5% (wt %) solutions using gravimetric measurement on aluminum foil in different mole ratio solutions of silicate inhibitor compared to active agent as KOH, expressed as (M.sub.i/M.sub.a). Solutions are tested at 90 C. for 20 min. Observations included as solution bubbling and metal appearance following exposure. Mole ratio 0.88 1.04 2.39 KASOLV16/KOH (M.sub.i/M.sub.a) Solution observations Minor bubbles, Minor bubbles, No bubbles during test (metal foil) 1-2 min 1-2 min Metal foil appearance No effect, No effect, No effect, after exposure bright, bright, bright, shiny shiny shiny Mass metal before (g) 0.16580 0.16042 0.16122 Mass metal after (g) 0.16573 0.16033 0.16120 Mass difference (g) 0.00007 0.00009 0.00002 Etch rate expressed as 2.55 3.28 0.73 angstroms/min

Example #3

(29) The following example demonstrates the dependence of metal safety on a ratio in moles of inhibitor to active agent (M.sub.i/M.sub.a) represented numerically and prepared from the solid composition as 5% (wt %) in water. In this case, the inhibitor chosen is an alkali silicate of the form potassium silicate (KASOLV 16, a powder with 53% SiO.sub.2 (wt %), PQ Corporation). The respective silicate is a solid form material with protective quality dependent upon the silicon dioxide content (wt % SiO.sub.2). In this example, the test specimens are parts from a flat panel display manufacturing line with microelectronic features which contain metal deposited areas which are coated by positive photoresist. The metal features are aluminum or aluminum alloys. The positive photoresist is of the variety AZ-4620 (novolak based), manufactured by AZ Electronic Materials (AZEM), located in Branchburg N.J. (USA, www.azem.com) and processed in the same or similar manner as described in this section to deposit a remaining layer of approximately <5 um, and more specifically 1-2 um. The FPD parts with resist coated aluminum features are exposed to the said solutions at the specified conditions for approximately 30 seconds, rinsed in deionized water, and dried. These parts are observed under a light microscope at a magnification range between 100-500 and the appearance of the aluminum is recorded. The parts are then prepared for SEM observation. The results are stated in Table 6.

(30) TABLE-US-00006 TABLE 6 Metal safety tests in various cleaners using optical microscopy and SEM on FPD specimens containing aluminum features with a resist coating. Included are different mole ratio solid form solutions of silicate inhibitor (M.sub.i) compared to active agent as KOH (M.sub.a), expressed as (M.sub.i/M.sub.a). Solutions are tested at 60 C. for 30 seconds. KOH Solid Solid Solid base- form form form Acetone line (no (silicate (silicate (silicate Solution Description cleans silicate) mix) mix) mix) Mole ratio Non- -0- 0.27 0.54 0.82 KASOLV16/KOH applicable (M.sub.i/M.sub.a) Metal feature Clean, Dark, Partial Partial Clean, observation (OM) bright black black- black- bright and surface ening ening and shiny shiny Metal feature Smooth Serious Partial Partial Smooth observation (SEM) surface, etch, etched etched surface, no pitting, and dull and dull no effect damage surface surface effect

Example #4

(31) The following example demonstrates the use of organic additives to minimize or eliminate the formation of residue during processing due to premature drying. The additives are considered as antideposition agents or dispersants. The materials are added as a solid raw material to the mixture, comprising approximately 10% of the total (wt %) represented as the solid form product. This product is diluted as 5% (wt %) in water and observed for any noticeable increase in viscosity of the fluid (thickening). An amount of approximately 5 milliliters (ml) is sent to test tubes of a volume capacity near 10 ml. The top is enclosed to not allow fluid to escape and they are shaken vigorously and set into a test tube rack to measure the foam level which forms over the liquid level. The foam levels are measured using the straight edge ruler device with increments in millimeters (mm). The solution is then applied to glass plates (microscope slides), an amount of 1-2 grams. The plates are transferred to a hot plate held at a temperature of approximately 90 C and allowed to dry. Periodically, more material is added to the plates to produce a visible dried residue. Once a visible dried material remains, the plates are transferred to a hot plate of a temperature >120 C and held there for 30 minutes. After this time, the plates are immersed into deionized water at room temperature for 5 minutes, removed from the liquid, allowed to stand erect and dry, and observed for any residue that remains. Measurements are assigned a number 0 (preferred) or 1 (not preferred). For example, residue removal with neutral water or wash liquid (base solution) is assigned a 0 for complete removal after 5 min, and no foam or thickening of the solution is assigned a 0 (preferred). The numbers are summed to give a total, the lower number is preferred. The observation of residue following this process is shown in Table 7.

(32) TABLE-US-00007 TABLE 7 Observation of solution thickening, foaming, and residue after water and wash solution exposure for 5 min, following processing mixtures on glass plates, hot plate drying, and rinsing with deionized water. Mixtures are prepared with 5% (wt %) of solid cleaner in water. The solid cleaner contains ~10% of the dispersing agent within the cleaner matrix. Viscosity Residue Residue # Additive Chemistry Manufacturer thickening Foam w/water w/wash Total: Base -None- not applicable 0 0 1 1 2 Kcitrate Chelate Noveon 0 0 1 0 1 Capstone Surfactant DuPont 0 0 1 0 1 PVP K15 Polyvinylpyrrolidone Int. Sci. Prod. (ISP) 0 0 1 0 1 Acrylidone Polyvinylpyrrolidone ISP 0 0 1 0 1 Aquazole Polyvinylpyrrolidone ISP 0 0 1 0 1 Stabileze Polyvinylpyrrolidone ISP 1 0 0 0 1 PVP/VA S630 Polyvinylpyrrolidone ISP 0 0 1 0 1 Gantrez Polyvinylpyrrolidone ISP 0 0 1 0 1 Klucel Cellulose Noveon 0 0 1 0 1 Croda 5M Surfactant Croda 0 1 0 0 1 DIPA Amine DOW 0 0 1 1 2 CMCAB Cellulose Eastman 0 0 1 1 2 Scripset 550 SMA Copolymer Ashland 0 0 1 1 2 LiSS Polystyrene sulfonate Tosoh 0 0 1 1 2 NaSS Polystyrene sulfonate Tosoh 0 0 1 1 2 Resinall Resin Resinall 0 0 1 1 2 PVA Alcohol Kuraray 0 0 2 1 3 Methocel Cellulose DOW 0 1 1 1 3 Croda C Surfactant Croda 0 1 1 1 3 Croda M Surfactant Croda 0 1 1 1 3 Croda L Surfactant Croda 0 1 1 1 3

(33) The best dispersing aids which inhibit residue formation are those exhibiting a low number in the column total (i.e. 1). For example, the potassium citrate (Kcitrate) exhibits a 1 due to non-thickening, non-foaming, and residue removal with the wash agent (i.e. 0).

Example #5

(34) The following example demonstrates the use of replenishment for increasing bath life of the resist remover (cleaning agent). The base solution (wash, cleaning agent, resist remover) comprises a mixture of inhibitor to active agent (M.sub.i/M.sub.a) of approximately 0.8 (i.e. M.sub.i/M.sub.a=0.8) and prepared as 2% (wt %) in water. The inhibitor is an alkali silicate of the form potassium silicate (KASOLV 16, a powder with 53% SiO.sub.2 (wt %), PQ Corporation) and active agent is KOH. In this example, the positive photoresist is of the variety AZ-4620 (novolak based), manufactured by AZ Electronic Materials (AZEM), located in Branchburg N.J. (USA, www.azem.com). The PR is dried in aluminum dishes to drive off all carrier solvent, collected, weighed, and dissolved into the cleaning agent at the specified concentrations. The representative amount of PR is the solid form amount, similar to that present on the device substrate. Using this information, conversion from the value of % w/w of loaded PR to substrates is possible with simple assumptions of known thickness and area coverage. Replenishment is normally conducted by adding back a known amount of concentrate at a level which is approximately one-half () of the concentration of the original value of the solution. Replenishment of solution activity corresponds to an increase in bath life.

(35) TABLE-US-00008 TABLE 8 Measured pH of solutions with varying amounts of PR (% w/w PR loading). A subsequent increase in solution activity as increased pH observed by the replenishment of the solution concentrate. Original solution concentration is approximately 2% (w/w) diluted in water. Change in Solution pH (ref is Solution Activity Ref previous # Solution Description as pH Solution solution) 1 2% (w/w) of remover 12.81 N/A N/A concentrate in water 2 Solution #1 + 0.25% 12.70 1 0.11 (w/w) PR, total PR = 0.25% (w/w) 3 Solution #2 + 0.25% 12.52 2 0.18 (w/w) PR, total PR = 0.50% (w/w) 4 Solution #3 + 0.25% 12.35 3 0.17 (w/w) PR, total PR = 0.75% (w/w) 5 Solution #4 + 0.25% 12.26 4 0.09 (w/w) PR, total PR = 1.00% (w/w) 6 Solution #5 + 1% (w/w) 12.54 5 +0.28 remover concentrate, total PR = 1.00% (w/w)