Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K13/00—Etching, surface-brightening or pickling compositions
  • C09K13/04—Etching, surface-brightening or pickling compositions containing an inorganic acid
  • C09K13/08—Etching, surface-brightening or pickling compositions containing an inorganic acid containing a fluorine compound
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/20—Dry etching; Plasma etching; Reactive-ion etching
  • H10P50/28—Dry etching; Plasma etching; Reactive-ion etching of insulating materials
  • H10P50/282—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of inorganic materials
  • H10P50/283—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of inorganic materials by chemical means
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/60—Wet etching
  • H10P50/66—Wet etching of conductive or resistive materials
  • H10P50/663—Wet etching of conductive or resistive materials by chemical means only
  • H10P50/667—Wet etching of conductive or resistive materials by chemical means only by liquid etching only
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P70/00—Cleaning of wafers, substrates or parts of devices
  • H10P70/40—Cleaning for reclaiming
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P90/00—Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
  • H10P90/12—Preparing bulk and homogeneous wafers
  • H10P90/16—Preparing bulk and homogeneous wafers by reclaiming or re-processing

Definitions

• the present invention relates to compositions and processes useful for the removal of low-k dielectric and other material layers from a rejected substrate or article having said material deposited thereon, for recycling/reworking and/or reuse of said substrate or article, and to products manufactured using same.
• Typical low-k materials include carbon doped oxides (CDO) deposited using commercially available precursors such as SiLKTM, AURORATM, CORALTM, or BLACK DIAMONDTM, for example using the proprietary BLACK DIAMONDTM process.
• CDO' s are typically formed using chemical vapor deposition (CVD) processes from organosilane and organosiloxane precursors.
• CVD carbon doped oxide low-k dielectrics typically consist of a porous, low density material having an overall dielectric constant less than about 3.2 and are used in a variety of semiconductor structures, typically by forming multiple layers of the CDO's within which other semiconductor structures, such as metal interconnect lines and vias, are formed.
• CDO's may be used as dielectric insulating layers (inter-metal dielectric (IMD) layers), capping layers and/or as gap filling material for certain structures.
• IMD inter-metal dielectric
• a microelectronic device wafer for example a silicon semiconductor wafer
• a microelectronic device wafer must be scrapped and hopefully recycled following the unacceptable processing of layers during the multi-layer device manufacturing process or qualification processes.
• Any number of processing problems may occur, for example, the non-uniform deposition of the CDO layer or a subsequent etching error.
• a number of quality control testing methods are performed following selected processing steps whereby the acceptability of the semiconductor wafer may be rejected and "scrapped" for various reasons resulting in a significant non-productive cost.
• the present invention Towards that end, it is an object of the present invention to provide an improved composition and process whereby metal stack materials, etch stop layers, and/or low-k dielectric layers, including CDO layers, may be removed from rejected microelectronic device structures for in- house recycling of said structures, whereby the compositions and processes are compatible with existing manufacturing processes and components.
• the underlying device surface e.g., silicon, is preferably undamaged by said removal composition.
• the composition of the invention may be formulated to comply with local environmental requirements. For example, high fluoride concentrations and high organic solvent concentrations may make a composition difficult to use in high volume manufacturing due to wastewater disposal issues.
• COD chemical oxygen demand
• the formulation may not be allowed in the facility wastewater for direct return to the environment.
• a fluoride treatment system may be employed to remove the fluoride from wastewater first, and then the water may be discharged to the environment.
• an organic disposal system such as an incinerator, may be employed.
• incineration systems may not accept wastewater samples containing high fluoride concentrations because the fluoride source may damage the incinerator materials of construction.
• the composition and/or process of using said composition preferably complies with local regulatory standards associated with the disposal of said composition.
• the present invention relates to compositions and processes useful for the removal of low-k dielectric and other material layers, including carbon doped oxide material layers, from a rejected microelectronic device structure having said material deposited thereon, for recycling and/or reuse of said microelectronic device structure, and methods of using such compositions and products or intermediate products manufactured using the same.
• the present invention relates to removal compositions useful in removing material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from the surface of a rejected microelectronic device structure for recycling of said microelectronic device structure, and methods of making and using the same.
• the compositions of the present invention include hydrofluoric acid.
• the present invention relates to a removal composition, comprising hydrofluoric acid and water, wherein said composition is further characterized by comprising at least one of the following components (I) and (II):
• composition is substantially devoid of amine species, and wherein said removal composition is suitable for removing material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from a microelectronic device having said material thereon.
• the present invention relates to a removal composition comprising hydrofluoric acid, amine-N-oxide, and water, wherein said removal composition is suitable for removing material selected from the group consisting of low-k dielectric material, metal stack material, and combinations thereof from a microelectronic device having said material thereon.
• the present invention relates to a removal composition comprising hydrofluoric acid, N-methylmorpholine-N-oxide, and water, wherein said removal composition is suitable for removing material selected from the group consisting of low-k dielectric material, metal stack material, and combinations thereof from a microelectronic device having said material thereon.
• the present invention relates to a removal composition
• a removal composition comprising hydrofluoric acid, water, at least one sulfur-containing solvent, and at least one glycol ether, wherein said composition is substantially devoid of amine, and wherein said removal composition is suitable for removing material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from a microelectronic device having said material thereon.
• the present invention relates to a removal composition
• a removal composition comprising hydrofluoric acid, water, tetramethylene sulfone, and at least one glycol ether, wherein said composition is substantially devoid of amine, and wherein said removal composition is suitable for removing material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from a microelectronic device having said material thereon.
• the at least one glycol ether comprises diethylene glycol butyl ether and the amount of water is in a range from about 10 wt% to 80 wt%, based on the total weight of the composition.
• Still another aspect relates to a stable removal composition, comprising hydrofluoric acid, at least one organic solvent, at least one oxidizing agent, at least one chelating agent, and water, wherein the composition is devoid of amines, and wherein said removal composition is temporally stable and suitable for removing material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from a microelectronic device having said material thereon.
• the chelating agent comprises CDTA.
• kits comprising, in one or more containers, one or more of the following reagents for forming a removal composition, wherein said removal composition comprises hydrofluoric acid and water, wherein said composition is further characterized by comprising at least one of the following components (I)-(II):
• kits are adapted to form a removal composition suitable for removing material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from a microelectronic device having said material thereon.
• the invention relates to a method of removing material from a microelectronic device having said material thereon, said method comprising contacting a microelectronic device structure with a removal composition for sufficient time to at least partially remove material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof, from the microelectronic device structure, wherein the removal composition includes hydrofluoric acid and water, and wherein said composition is further characterized by comprising at least one of the following components (I)-(II): (I) at least one amine; or (II) at least one organic solvent, wherein the composition is substantially devoid of amine species.
• the present invention relates to a method of manufacturing a microelectronic device, said method comprising contacting a microelectronic device structure with a removal composition for sufficient time to at least partially remove material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from the microelectronic device structure having said material thereon, wherein the removal composition includes hydrofluoric acid and water, and wherein said composition is further characterized by comprising at least one of the following components (I)-(II):
• composition is substantially devoid of amine species.
• a further aspect of the invention relates to microelectronic device wafers reclaimed using the methods of the invention comprising contacting the rejected microelectronic device wafer with a removal composition for sufficient time to at least partially remove material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from the microelectronic device, using the methods and/or compositions described herein, and optionally, incorporating the microelectronic device structure into a product (e.g., microelectronic device).
• a product e.g., microelectronic device
• Yet another aspect of the invention relates to improved microelectronic devices and microelectronic device structures, and products incorporating same, made using the methods of the invention comprising contacting the microelectronic device structure with a removal composition for sufficient time to at least partially remove material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof from the microelectronic device, using the methods and/or compositions described herein, and optionally, incorporating the microelectronic device structure into a product (e.g., microelectronic device).
• Another aspect of the invention relates to a method of removing low-k dielectric material from a microelectronic device having said low-k dielectric material thereon, said method comprising:
• the removal composition includes hydrofluoric acid and water, and wherein the pH of a 20:1 dilution of the removal composition in water is in a range from about 2.5 to about 4.5;
• Still another aspect of the invention relates to a method of recycling a microelectronic device substrate, said method comprising:
• microelectronic device structure comprising material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof with a removal composition for sufficient time to at least partially remove said material from the microelectronic device structure to produce a recycled microelectronic device structure;
• the removal composition includes hydrofluoric acid and water, and wherein said composition is further characterized by comprising at least one of the following components (I)-(II): (I) at least one amine; or
• composition is substantially devoid of amine species.
• Yet another aspect of the invention relates to a microelectronic device comprising a microelectronic device wafer and at least one layer thereon, wherein said at least one layer is selected from the group consisting of low-k dielectric material, barrier layer material, metals, metal alloys, and etch stop layers, and wherein the microelectronic device wafer is reclaimed.
• the microelectronic device wafer comprises silicon and the reclaimed wafer has a thickness that is greater than 95 % of the thickness of a new wafer, more preferably greater than 98%, and most preferably greater than 99% of the thickness of a new wafer.
• Another aspect of the invention relates to an article of manufacture comprising a removal composition of the invention, a microelectronic device, and material selected from the group consisting of low-k dielectric material, etch stop material, metal stack material, and combinations thereof, wherein the removal composition includes hydrofluoric acid and water, and wherein said composition is further characterized by comprising at least one of the following components (I)-(II):
• composition is substantially devoid of amine species.
• FIG. 1 is a plot of the etch rate, in A min "1 , of various low-k dielectric materials as a function of temperature.
• FIG. 2 is a plot of the etch rate, in A min "1 , of various metal stack materials as a function of temperature.
• FIG. 3 is a plot of the etch rate, in A min '1 , of various underlying silicon-containing materials as a function of temperature.
• the present invention relates to removal compositions and processes useful for the removal of low-k dielectric and other material layers, including carbon doped oxide material, from a rejected microelectronic device structure having said material thereon, for in-house recycling of said microelectronic device structure.
• Microelectronic device corresponds to semiconductor substrates, flat panel displays, and microelectromechanical systems (MEMS), manufactured for use in microelectronic, integrated circuit, or computer chip applications. It is to be understood that the term “microelectronic device” and “microelectronic device structure” is not meant to be limiting in any way and includes any substrate or structure that will eventually become a microelectronic device or microelectronic assembly. [0034] As used herein, "about” is intended to correspond to + 5 % of the stated value.
• low-k dielectric material corresponds to any material used as a dielectric material in a layered microelectronic device, wherein the material has a dielectric constant less than about 3.5.
• the low-k dielectric materials include low-polarity materials such as silicon- containing organic polymers, silicon-containing hybrid organic/inorganic materials, organosilicate glass (OSG), TEOS, fluorinated silicate glass (FSG), and carbon-doped oxide (CDO) glass.
• low-k dielectric material further includes silicon nitride materials. It is to be appreciated that the low-k dielectric materials may have varying densities and varying porosities.
• the term "semi-aqueous" refers to a mixture of water and organic components. Semi-aqueous removal compositions must not damage the material located adjacent to the low-k dielectric material removed using said composition. Adjacent materials include bare silicon, polysilicon, and combinations thereof. Depending on the desired results, adjacent materials may also include etch stop-layers and metal stack materials. Preferably, less than 100 A of adjacent materials are removed, more preferably less than 50 A, even more preferably less than 20 A, even more preferably less than 10 A and most preferred less than 1 A of the adjacent materials are removed using the compositions of the invention. ).
• At least 95% of the low-k dielectric is removed, more preferably at least 99%, even more preferably at least 99.9%, and most preferably 100%. It should be appreciated that there will be occasions when it is desired to remove metal stack materials and/or etch stop layers, in addition to low-k dielectric materials, in the process of regenerating the rejected microelectronic device structure.
• metal stack materials correspond to: tantalum, tantalum nitride, titanium nitride, titanium, nickel, cobalt, tungsten, and suicides thereof; copper layers; aluminum layers; Al/Cu layers; alloys of Al; alloys of Cu; hafnium oxides; hafnium oxysilicates; zirconium oxides; lanthanide oxides; titanates; and combinations thereof on the microelectronic device. It is to be appreciated by one skilled in the art that although the compositions of the invention are described as removing low-k dielectric materials, the recitation that the compositions are useful for removing low-k dielectric materials is intended to include the removal of metal stack materials as well, when desired.
• etch stop layers include silicon carbide (SiC), silicon carbon nitride (SiCN), silicon carbon oxide (SiCO), silicon oxynitride (SiON), copper, silicon germanium (SiGe), SiGeB, SiGeC, AlAs, InGaP, InP, InGaAs, and combinations thereof. It is to be appreciated by one skilled in the art that although the compositions of the invention are described as removing low-k dielectric materials, the recitation that the compositions are useful for removing etch stop layers is intended to include the removal of metal stack materials as well, when desired.
• the requirements of a successful wafer reclamation include, but are not limited to, zero or negligible front-side, bevel edge, and/or backside silicon pitting, less than 50 particles at 0.12 ⁇ m, a total thickness variation (TTV) of less than about 5 ⁇ m, and/or a surface metal contamination of less than 1 x 10 10 atoms cm "2 .
• TTV total thickness variation
• Bevel edge and backside cleaning is used to remove photoresist and electroplated copper from the outermost edge and backside of the device wafer, which reduces particle and metal contamination during subsequent processing.
• total thickness variation corresponds to the absolute difference between the maximum and the minimum thickness of a microelectronic device wafer as determined using a thickness scan or series of point thickness measurements known in the art.
• the microelectronic device structure to be reclaimed includes a wafer comprising bare silicon, poly-silicon, and combinations thereof, and can be any diameter or thickness conventionally used in the art.
• compositions of the invention may be embodied in a wide variety of specific formulations, as hereinafter more fully described.
• compositions of the present invention relate to removal compositions useful in removing low-k dielectric and metal stack material from the surface of a rejected microelectronic device structure for recycling of said microelectronic device structure, and methods of making and using the same.
• the compositions of the present invention include hydrofluoric acid.
• the compositions include at least one amine species, hydrofluoric acid, optionally at least one organic solvent, optionally at least one additional acid species, optionally at least one chelating agent, and optionally water, present in the following ranges, based on the total weight of the composition: component % by weight amine(s) about 1% to about 70.0% hydrofluoric acid about 1% to about 70.0% optional organic solvent(s) 0 to about 80.0% optional additional acid(s) 0 to about 80% optional chelating agent(s) O to about 10% optional water 0 to about 50%
• the removal composition may comprise, consist of, or consist essentially of at least one amine species, hydrofluoric acid, optionally at least one organic solvent, optionally at least one additional acid species, optionally at least one chelating agent, and optionally water.
• the specific proportions and amounts of amine(s), hydrofluoric acid source(s), optional organic solvent(s), optional additional acid(s), optional chelating agent(s), and water, in relation to each other may be suitably varied to provide the desired removal action of the composition for the low-k dielectric material and/or processing equipment, as readily determinable within the skill of the art without undue effort.
• compositions of the invention have a pH value in a range from about 1 to about 7, more preferably about 2.5 to about 4.5, most preferably about 3 to about 3.5, when diluted 20:1 with deionized water.
• the amine species may include, but are not limited to, straight-chained or branched Ci-C 20 alkylamines, substituted or unsubstituted C 6 -Ci 0 arylamines, glycolamines, alkanolamines, and amine- N-oxides including, but not limited to, pyridine; 2-ethylpyridine; 2-methoxypyridine and derivatives thereof such as 3-methoxypyridine; 2-picoline; pyridine derivatives; dimethylpyridine; piperidine; piperazine; triethylamine; triethanolamine; ethylamine; methylamine; isobutylamine; tert-butylamine; tributylamine; dipropylamine; dimethylamine; diglycol amine; monoethanolamine; pyrrole; isoxazole; 1,2,4-triazole; bipyridine; pyrimidine; pyrazine; pyridazine; quinoline; iso
• the amine species may comprise a combined amine-hydrogen fluoride salt.
• the removal compositions of the present invention may include at least one amine- hydrogen fluoride salt, optionally at least one organic solvent, optionally at least one organic acid, optionally at least one chelating agent, and optionally water.
• Amine-hydrogen fluoride salts are nonvolatile and as such, changes in the solution pH due to evaporation of the amine species is avoided.
• Amine-hydrogen fluoride salts contemplated herein include, but are not limited to, any of the above- enumerated amines in combination with HF to form an amine-hydrogen fluoride salt.
• the amine-hydrogen fluoride salt species when used, comprises isoxazole:HF and/or NMMO.HF. It is to be appreciated that the ratio of amine:hydrogen fluoride salt may vary from about 1 :1 to about 20:1 depending on the conditions of the reaction and the nature of the low-k dielectric material to be removed.
• Water may be included in the compositions of the invention in part because of its ability to solubilize the fluoride species. Preferably, the water is deionized.
• bare silicon, polysilicon, silicon carbide, silicon carbon nitride, and silicon carbon oxide e.g., bare silicon, polysilicon, silicon carbide, silicon carbon nitride, and silicon carbon oxide.
• Organic solvents contemplated herein include, but are not limited to, alcohols, ethers, pyrrolidinones, glycols, carboxylic acids, and glycol ethers such as methanol, ethanol, isopropanol, butanol, and higher alcohols (including diols, triols, etc.), 2,2,3,3,4,4,5,5-octafluoro-l-pentanol, lH,lH,9H-perfluoro-l- nonanol, perfluoroheptanoic acid, lH,lH,7H-dodecafluoro-l-heptanol, perfluoropentanoic acid, lH,lH,8H,8H-dodecafluoro-l ,8-octanediol, 2,2,3,3,4,4,5,5-octafluoro-l ,6-hexanediol, 5H- perfluoropent
• the solvent may comprise other amphiphilic species, i.e., species that contain both hydrophilic and hydrophobic moieties similar to surfactants.
• Hydrophobic properties may generally be imparted by inclusion of a molecular group consisting of hydrocarbon or fluorocarbon groups and the hydrophilic properties may generally be imparted by inclusion of either ionic or uncharged polar functional groups.
• the organic solvent comprises sulfolane, butyl carbitol, dipropylene glycol propyl ether, or mixtures thereof.
• the optional additional acid(s) assist in breaking up and solubilizing the cross-linked polymer bonds in the low-k dielectric material.
• Additional acids contemplated herein include, but are not limited to, boric acid, oxalic acid, succinic acid, citric acid, lactic acid, acetic acid, trifluoroacetic acid, tetrafluoroboric acid, hydrofluoric acid, hydrochloric acid, formic acid, fumaric acid, acrylic acid, malonic acid, maleic acid, malic acid, L-tartaric acid, methyl sulfonic acid, trifluoromethanesulfonic acid, iodic acid, mercaptoacetic acid, thioacetic acid, glycolic acid, sulfuric acid, nitric acid, propynoic acid, pyruvic acid, acetoacetic acid, and combinations thereof.
• Chelating agent(s) may be added to reduce or eliminate metal contaminating species on the surface of the device during wafer reclamation.
• Chelating agent(s) contemplated herein include, but are not limited to: ⁇ -diketonate compounds such as acetylacetonate, l,l,l-trifluoro-2,4-pentanedione, and l,l,l,5,5,5-hexafluoro-2,4-pentanedione; carboxylates such as formate and acetate and other long chain carboxylates; and amides (and amines), such as bis(trimethylsilylamide) tetramer.
• Additional chelating agents include amines and amino acids (i.e. glycine, alanine, citric acid, acetic acid, maleic acid, oxalic acid, malonic acid, succinic acid, nitrilotriacetic acid, iminodiacetic acid, etidronic acid, ethylenediamine, ethylenediaminetetraacetic acid (EDTA), and (l,2-cyclohexylenedinitrilo)tetraacetic acid (CDTA), and monoethanolamine (MEA)).
• amines and amino acids i.e. glycine, alanine, citric acid, acetic acid, maleic acid, oxalic acid, malonic acid, succinic acid, nitrilotriacetic acid, iminodiacetic acid, etidronic acid, ethylenediamine, ethylenediaminetetraacetic acid (EDTA), and (l,2-cyclohexylenedinitrilo
• fluorinated beta-diketone chelating agents can be used in the absence of a base.
• the chelating agent may be introduced to the composition at the manufacturer, prior to introduction of the composition to the device wafer, or alternatively at the device wafer, i.e., in situ. It is further contemplated that in addition to chelating agent(s), other components may be added to the composition to dilute, maintain and/or increase the concentration of other components in the composition.
• compositions may optionally include additional components, including active as well as inactive ingredients, e.g., surfactants, stabilizers, passivators, dispersants, pH stabilizing agents, oxidants, etc.
• active e.g., surfactants, stabilizers, passivators, dispersants, pH stabilizing agents, oxidants, etc.
• Specific embodiments of this aspect of the removal composition may be in concentrated form and include the following, wherein the components may be present in the following ranges, based on the total weight of the composition: component % by weight preferred/% by weight amine(s) about 1 % to about 30.0% about 5% to about 15.0% hydrofluoric acid about 5% to about 45.0% about ] 15% to about 25.0% organic solvent(s) about 10% to about 60% about 20% to about 50% additional acid(s) about 5% to about 25% about 10% to about 25% water about 10% to about 60% about 15% to about 30%
• amine-hydrogen fluoride salt about 1% to about 40.0% about 5% to about 30.0% hydrofluoric acid about 0.01% to about 5.0% about 1% to about 2% organic solvent(s) about 40% to about 75% about 50% to about 70% additional acid(s) about 1% to about 20% about 5% to about 20% water about 0.01% to about 20% about 1 % to about 20%
• amine-hydrogen fluoride salt about 1% to about 40.0% about 30% to about 35.0% hydrofluoric acid about 0.01% to about 5.0% about 1% to about 2% organic solvent(s) about 45% to about 75% about 55% to about 70% water about 0.01% to about 10% about 1% to about 2%
• component % by weight preferred/% by weight amine about 1 % to about 40% about 15 % to about 25 % hydrofluoric acid about 5% to about 50% about 35% to about 45% water about 20% to about 80% about 35% to about 45%
• component % by weight preferred/% by weight amine about 1% to about 30.0% about 5% to about 20% hydrofluoric acid about 5% to about 50% about 10% to about 30% organic solvents) about 1% to about 80% about 10% to about 65% water about 1% to about 80% about 15% to about 70%
• the pH of a 20:1 dilution of the semi-aqueous amine-containing removal composition in deionized water is in a range from about 2.5 to about 4.5.
• the semi-aqueous amine-containing removal composition contains less than 30 wt. %, preferably less than 10 wt%, more preferably less than 2wt%, even more preferably less than 1 wt% and most preferred is devoid of tetrahydrofurfuryl alcohol.
• the removal composition may comprise, consist of, or consist essentially of any of the foregoing embodiments.
• the low-k dielectric materials removed using the removal compositions of the invention include CORALTM, BLACK DIAMONDTM (hereinafter BD), derivatives of CORAL, derivatives of BD, AURORA®, derivatives of AURORA®, etc.
• CORALTM CORALTM
• BD BLACK DIAMONDTM
• derivatives of CORAL CORAL
• derivatives of BD correspond to CORAL and BD materials, respectively, that were deposited using alternative, often proprietary, deposition processes.
• the utilization of a different processing technique will result in a CORAL and BD material that differs from CORALTM and BLACK DIAMONDTM, respectively.
• Another aspect of the invention relates to the removal compositions as used and further containing such low-k dielectric residue.
• the foregoing embodiments of the removal composition of the invention may further include low-k dielectric and metal stack material residue(s).
• the low-k dielectric material comprises silicon-containing compounds that dissolve in the removal composition.
• the removal composition includes at least one amine species, hydrofluoric acid, water, material residue, optionally at least one organic solvent, optionally at least one chelating agent, and optionally at least one additional acid species, wherein the material residue includes low-k dielectric material residue, metal stack material residue, and combinations thereof.
• the removal composition includes at least one amine-hydrogen fluoride salt species, additional hydrofluoric acid, at least one organic solvent, at least one additional acid species, material residue and water, wherein the material residue includes low-k dielectric material residue, metal stack material residue, and combinations thereof.
• compositions of this aspect of the invention may be formulated in the following Formulations A-BB, wherein all percentages are by weight, based on the total weight of the formulation:
• Formulation A Tetrafluoroboric acid 4.7 wt%; Triethanolamine:HF 11.7 wt%; HF 1.7 wt%; Ethylene glycol 39.6 wt%; Sulfolane 10.0 wt%; Butyl carbitol 15.0 wt%; Water 17.3 wt%
• Formulation B Tetrafluoroboric acid 4.7 wt%; Pyridine:HF 16.0 wt%; HF 1.7 wt%; Ethylene glycol 39.6 wt%; Sulfolane 10.0 wt%; Butyl carbitol 15.0 wt%; Water 13.0 wt%
• Formulation C Tetrafluoroboric acid 5.9 wt%; Pyridine:HF 8.0 wt%; HF 1.7 wt%; Ethylene glycol 39.6 wt%; Sulfolane 10.0 wt%; Butyl carbitol 19.0 wt%; Water 15.8 wt%
• Formulation D Acetic acid 17.0 wt%; Pyridine:HF 27.0 wt%; HF 1.2 wt%; Ethylene glycol 27.6 wt%; Sulfolane 10.0 wt%; DMSO 16.0 wt%; Water 1.2 wt%
• Formulation E Pyridine:HF 32.0 wt%; HF 1.3 wt%; Ethylene glycol 32.4 wt%; Sulfolane 13.0 wt%; DMSO 20.0 wt%; Water 1.3 wt%
• Formulation F Pyridine:HF 32.0 wt%; Propylene glycol 35.0 wt%; Sulfolane 13.0 wt%; DMSO 20.0 wt%
• Formulation G Pyridine:HF 31.1 wt%; HF 1.4 wt%; Propylene glycol 34.1 wt%; Sulfolane 12.6 wt%; DMSO 19.4 wt%; Water 1.4 wt%
• Formulation H Pyridine:HF 32.0 wt%; HF 1.7 wt%; Ethylene glycol 39.6 wt%; Sulfolane 10.0 wt%; DMSO 15.0 wt%; Water 1.7 wt%
• Formulation I Acetic acid 13.0 wt%; Isoxazole 7.0 wt%; HF 16.2 wt%; Ethylene glycol 22.1 wt%; Sulfolane 10.0 wt%; DMSO 15.0 wt%; Water 16.7 wt%
• Formulation J Acetic acid 13.0 wt%; 1 ,2,4-Triazole 7.0 wt%; HF 16.2 wt%; Ethylene glycol 22.1 wt%; Sulfolane 10.0 wt%; DMSO 15.0 wt%; Water 16.7 wt%
• Formulation K Acetic acid 13.0 wt%; Isoxazole 7.0 wt%; HF 16.3 wt%; Ethylene glycol 24.0 wt%; Sulfolane 15.0 wt%; Water 24.7 wt%
• Formulation L Acetic acid 13.0 wt%; Isoxazole 7.0 wt%; HF 16.3 wt%; Ethylene glycol 24.0 wt%; Sulfolane 10.0 wt%; NMP 13.0 wt%; Water 16.7 wt%
• Formulation M Acetic acid 13.0 wt%; Isoxazole 7.0 wt%; HF 16.3 wt%; Ethylene glycol 24.0 wt%; Sulfolane 10.0 wt%; Methyl carbitol 13.0 wt%; Water 16.7 wt%
• Formulation N Acetic acid 13.0 wt%; Isoxazole 7.0 wt%; HF 16.3 wt%; Ethylene glycol 24.0 wt%; Sulfolane 10.0 wt%; Dipropylene glycol methyl ether 13.0 wt%; Water 16.7 wt%
• Formulation O Acetic acid 15.0 wt%; Isoxazole 9.0 wt%; HF 17.2 wt%; Ethylene glycol 25.9 wt%; Sulfolane 15.0 wt%; Water 17.9 wt%
• Formulation P Isoxazole 10.3 wt%; HF 20.4 wt%; Ethylene glycol 30.7 wt%; Sulfolane 17.2 wt%; Water 21.4 wt%
• Formulation O acetic acid 21.1 wt%; Isoxazole 12.0 wt%; HF 23.0 wt%; Sulfolane 20.0 wt%; Water 23.9 wt%
• Formulation R acetic acid 18.0 wt%; Isoxazole 10.2 wt%; HF 20.2 wt%; Sulfolane 30.4 wt%; Water 21.2 wt%
• Formulation S acetic acid 26.4 wt%; Isoxazole 15.0 wt%; HF 28.7 wt%; Water 29.9 wt%
• Formulation T Isoxazole 15.2 wt%; HF 29.1 wt%; Sulfolane 25.4 wt%; Water 30.3 wt%
• Formulation U Isoxazole 20.4 wt%; HF 39.0 wt%; Water 40.6 wt% Formulation V: 2-ethylpyridine 20.4 wt%; HF 39.0 wt%; Water 40.6 wt% Formulation W: 2-Methoxypyridine 20.4 wt%; HF 39.0 wt%; Water 40.6 wt% Formulation X: Piperidine 20.4 wt%; HF 39.0 wt%; Water 40.6 wt% Formulation X: Piperidine 20.4 wt%; HF 39.0 wt%; Water
• Formulation Y NMMO 8.0 wt%; HF 17.6 wt%; Sulfolane 15.0 wt%; Butyl carbitol 33.0 wt%; Water 26.4 wt%
• Formulation Z 2-Methoxypyridine 7.0 wt%; HF 15.7 wt%; Sulfolane 61.0 wt%; Water 16.3 wt%
• Formulation AA NMMO 7.0 wt%; HF 15.7 wt%; Water 77.3 wt%
• Formulation BB NMMO 7.0 wt%; HF 15.7 wt%; Sulfolane 10.0 wt%; Water 67.3 wt%
• the range of weight percent ratios of the components are: about 0.1 :1 to about 10:1 etchant(s) relative to amine(s), preferably about 1 :1 to about 5:1 , and most preferably about 2:1 to about 3:1; and about 1 :1 to about 30:1 water relative to amine(s), preferably about 5:1 to about 20:1, and most preferably about 10:1 to about 15:1.
• the present invention relates to removal compositions useful in removing materials selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof from the surface of a rejected microelectronic device structure, wherein said removal compositions are substantially devoid of amine species.
• said removal compositions are substantially devoid of amine species.
• substantially devoid corresponds to less than about 1 wt. %, more preferably less than 0.5 wt. %, and most preferably less than 0.1 wt. % of the composition, based on the total weight of said composition.
• this aspect of the present invention may include hydrofluoric acid and at least one organic solvent. More specifically, the compositions of the invention may include hydrofluoric acid, at least one organic solvent, water, optionally at least one organic acid, and optionally at least one chelating agent, present in the following ranges, based on the total weight of the composition: component % by weight hydrofluoric acid about 0.01% to about 50.0% organic solvent(s) about 20% to about 70.0% optional organic acid(s) 0 to about 80.0% optional chelating agent(s) 0 to about 10% water about 0.01% to 80%
• the removal composition may comprise, consist of, or consist essentially of hydrofluoric acid, at least one organic solvent, water, optionally at least one organic acid, and optionally at least one chelating agent.
• hydrofluoric acid source(s), organic solvent(s), water, optional organic acid(s), and optional chelating agent(s), in relation to each other may be suitably varied to provide the desired removal action of the composition for the materials selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof, and/or processing equipment, as readily determinable within the skill of the art without undue effort.
• this aspect of the present invention includes at least 10 wt % HF, based on the total weight of the composition.
• the removal composition of this aspect is devoid of oxidizer and/or carbonate-containing species.
• the amount of water present in the removal composition of this aspect is preferably in a range from 10 wt % to 80 wt. %, more preferably 10 wt% to about 75 wt%, based on the total weight of the composition.
• Compositions of this aspect have a pH value in a range from about 1 to about 7, more preferably about 2.5 to about 4.5, most preferably about 2.8 to about 3.5, when diluted 20:1 with deionized water.
• the preferred organic solvent(s), chelating agent(s), and organic acid(s) species were previously introduced hereinabove.
• the water is deionized.
• compositions may optionally include additional components, including active as well as inactive ingredients, e.g., surfactants, stabilizers, passivators, chelating agents, dispersants, pH stabilizing agents, oxidants, etc.
• active e.g., surfactants, stabilizers, passivators, chelating agents, dispersants, pH stabilizing agents, oxidants, etc.
• surfactants contemplated include nonionic, anionic, cationic (based on quaternary ammonium cations) and/or zwitterionic surfactants.
• suitable non-ionic surfactants may include fluoroalkyl surfactants, ethoxylated fluorosurfactants, polyethylene glycols, polypropylene glycols, polyethylene or polypropylene glycol ethers, carboxylic acid salts, dodecylbenzenesulfonic acid or salts thereof, polyacrylate polymers, dinonylphenyl polyoxyethylene, silicone or modified silicone polymers, acetylenic diols or modified acerylenic diols, alkylammonium or modified alkylammonium salts, and alkylphenol polyglycidol ether, as well as combinations comprising at least one of the foregoing.
• the nonionic surfactant may be an ethoxylated fluorosurfactant such as ZONYL® FSO-100 fluorosurfactant (DuPont Canada Inc., Mississauga, Ontario, Canada).
• Anionic surfactants contemplated in the compositions of the present invention include, but are not limited to, fluorosurfactants such as ZONYL® UR and ZONYL® FS-62 (DuPont Canada Inc., Mississauga, Ontario, Canada), sodium alkyl sulfates, ammonium alkyl sulfates, alkyl (Ci 0 -Ci 8 ) carboxylic acid ammonium salts, sodium sulfosuccinates and esters thereof, e.g., dioctyl sodium sulfosuccinate, and alkyl (Ci 0 -Ci 8 ) sulfonic acid sodium salts.
• Cationic surfactants contemplated include alkyltetramethylammonium salts such as cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium hydrogen sulfate.
• Suitable zwitterionic surfactants include ammonium carboxylates, ammonium sulfates, amine oxides, N-dodecyl-N,N-dimethylbetaine, betaine, sulfobetaine, alkylammoniopropyl sulfate, and the like.
• an embodiment of this aspect of the invention may be present in concentrated form and includes the following components present in the following ranges, based on the total weight of the composition: component % by weight hydrofluoric acid about 5% to about 40% organic solvent(s) about 10% to about 70% water about 5% to 80%
• the pH of a 20:1 dilution of the removal composition in deionized water is in a range from about
• the foregoing embodiment of the removal composition of the invention may further include materials selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof.
• the materials dissolve in the removal composition.
• This embodiment may be formulated in the following Formulations CC-HH, wherein all percentages are by weight, based on the total weight of the formulation:
• Formulation CC HF 20.1 wt%; Butyl carbitol 57.5 wt%; Sulfolane 1.5 wt%; Water 20.9 wt% Formulation DD: HF 37.4 wt%; Butyl carbitol 21.7 wt%; Sulfolane 2.2 wt%; Water 38.7 wt% Formulation EE: HF 20.1 wt%; Butyl carbitol 21.7 wt%; Sulfolane 2.2 wt%; Water 56.0 wt% Formulation FF: 10.04% HF, 10.8% butyl carbitol, 2.2% sulfolane and 76.96% water Formulation GG: HF 20.1 wt%; Butyl carbitol 10.8 wt%; Sulfolane 2.2 wt%; Water 66.9 wt% Formulation HH: HF 20.1 wt%; Butanol 10.8 wt%; Sulf
• the removal compositions of the invention are formulated in the following embodiments, wherein all percentages are by weight, based on the total weight of the formulation:
• this aspect of the invention relates to a removal composition including hydrogen fluoride, diethylene glycol butyl ether, sulfolane and water.
• the range of weight percent ratios of the components are: about 0.1 :1 to about 10:1 solvent(s) relative to etchant(s), preferably about 0.5:1 to about 5:1, and most preferably about 1 :1 to about 3:1; and about 0.1 :1 to about 10:1 water relative to etchant(s), preferably about 0.5:1 to about 5:1, and most preferably about 1 :1 to about 3:1.
• the removal composition may further include materials selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof, wherein the material is dissolved in the removal composition and the removal composition remains viable for its intended use.
• the removal composition includes water, sulfolane, diethylene glycol butyl ether, and hydrogen fluoride, wherein the amount of water is in a range from 10 wt. % to about 75 wt. %, based on the total weight of the composition, with the provision that the composition is substantially devoid of amine.
• the compositions of the invention include at hydrofluoric acid, at least one organic solvent, at least one oxidizing agent, and water, with the provision that the composition be substantially devoid of amine.
• Oxidizing agents contemplated herein include, but are not limited to, hydrogen peroxide (H 2 O 2 ), oxone, oxone tetrabutylammonium salt, ferric nitrate (Fe(NO 3 ) 3 ), potassium iodate (KIO 3 ), potassium permanganate (KMnO 4 ), nitric acid (HNO 3 ), ammonium chlorite (NH 4 ClO 2 ), ammonium chlorate (NH 4 ClO 3 ), ammonium iodate (NH 4 IO 3 ), ammonium perborate (NH 4 BO 3 ), ammonium perchlorate (NH 4 ClO 4 ), ammonium periodate (NH 4 IO 3 ), ammonium persulfate ((NH 4 )
• an embodiment of this aspect of the invention may be present in concentrated form and includes the following components present in the following ranges, based on the total weight of the composition: component % by weight preferred/% by weight hydrofluoric acid about 10% to about 40% about 15% to about 25% organic solvent(s) about 10% to about 80% about 20% to about 55% water about 10% to about 80% about 15% to about 55% oxidizing agent about 0.1% to about 15% about 1% to about 10%
• the pH of a 20:1 dilution of the removal composition in deionized water is in a range from about
• the foregoing embodiment of the removal composition of the invention may further include materials selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof.
• the materials dissolve in the removal composition.
• This embodiment may be formulated in the following Formulations II-KK, wherein all percentages are by weight, based on the total weight of the formulation:
• Formulation II HF 18.3 wt%; Butyl carbitol 52.3 wt%; Sulfolane 1.3 wt%; Water 19 wt%; H 2 O 2 9.1 wt%
• Formulation JJ HF 20.1 wt%; Butyl carbitol 21.7 wt%; Sulfolane 2.2 wt%; H 2 O 2 1 wt%; Water 55.0 wt%
• Formulation KK HF 20.1 wt%; Butyl carbitol 21.7 wt%; Sulfolane 2.2 wt%; HNO 3 0.97 wt%; Water 55.3 wt%
• the compositions of the invention include at hydrofluoric acid, at least one organic solvent, at least one oxidizing agent, water, and at least one copper chelating agent, with the provision that the composition be substantially devoid of amine.
• This compositional embodiment is particularly useful for the removal of low-k dielectric material, etch stop layers and/or the metal film stacks without damaging the underlying device substrate and without the re-deposition or precipitation of copper on the surface of said substrate.
• an embodiment of this aspect of the invention may be present in concentrated form and includes the following components present in the following ranges, based on the total weight of the composition: component % by weight preferred/% by weight hydrofluoric acid about 5% to about 30% about 10% to about 20% organic solvent(s) about 5% to about 40% about 10% to about 25% water about 40% to about 90% about 50% to 80% oxidizing agent about 0.1% to about 15% about 1% to about 5% chelating agent about 0.01% to about 5% about 0.1 % to about 2%
• the pH of a 20:1 dilution of the removal composition in deionized water is in a range from about
• the foregoing embodiment of the removal composition of the invention may further include materials selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof.
• the materials dissolve in the removal composition.
• This embodiment may be formulated in the following Formulations LL-QQ, wherein all percentages are by weight, based on the total weight of the formulation:
• Formulation LL HF 20.1 wt%; Butyl carbitol 21.7 wt%; Sulfolane 2.2 wt%; H 2 O 2 1 wt%; CDTA 0.15 wt%; Water 54.85 wt%
• Formulation MM HF 20.1 wt%; Butyl carbitol 21.7 wt%; Sulfolane 2.2 wt%; H 2 O 2 1 wt%; EDTA 0.15 wt%; Water 54.85 wt%
• Formulation NN HF 20.1 wt%; Butyl carbitol 21.7 wt%; Sulfolane 2.2 wt% H 2 O 2 1 wt%; MEA 0.15 wt%; Water 54.85 wt%
• Formulation OQ HF 10.04 wt%; Butyl carbitol 10. 8 wt%; Sulfolane 2.2 wt%; H 2 O 2 1 wt%; CDTA 0.15 wt%; Water 75.81 wt%
• Formulation PP HF 10.04 wt%; Butyl carbitol 10.8 wt%; Sulfolane 2.2 wt%; H 2 O 2 1 wt%; acac 2 wt%; Water 73.96 wt%
• Formulation OQ HF 10.04 wt%; Butyl carbitol 10.8 wt%; Sulfolane 2.2 wt%; H 2 O 2 5 wt%; CDTA 0.15 wt%; Water 71.81 wt%
• the range of weight percent ratios of the components are: about 0.1 :1 to about 10:1 etchant(s) relative to oxidant(s), preferably about 0.5:1 to about 5:1, and most preferably about 1 :1 to about 3:1; about 0.1 :1 to about 10:1 solvent(s) relative to oxidant(s), preferably about 1 :1 to about 5:1, and most preferably about 2:1 to about 3.5:1; about 0.001 :1 to about 0.1 chelating agent(s) relative to oxidant(s), preferably about 0.01 :1 to about 0.05:1; and about 1 :1 to about 30:1 water relative to oxidants), preferably about 5:1 to about 25:1, and most preferably about 10:1 to about 20:1.
• the chelating agent may be introduced to the composition of this aspect at the manufacturer, prior to introduction of the composition to the device wafer, or alternatively at the device wafer, i.e., in situ. It is further contemplated that in addition to chelating agent(s), other components may be added to the composition to dilute, maintain and/or increase the concentration of other components in the composition.
• the low-k dielectric materials removed using the removal compositions of the invention include CORALTM, BLACK DIAMONDTM (hereinafter BD), derivatives of CORAL, derivatives of BD, AURORA®, derivatives of AURORA®, etc.
• CORALTM CORALTM
• BD BLACK DIAMONDTM
• derivatives of CORAL CORAL
• derivatives of BD correspond to CORAL and BD materials, respectively, that were deposited using alternative, often proprietary, deposition processes.
• the utilization of a different processing technique will result in a CORAL and BD material that differs from CORALTM and BLACK DIAMONDTM, respectively.
• Another aspect of the invention relates to the removal compositions as used and further containing such low-k dielectric residue.
• the removal compositions of this aspect are also effective at concurrently removing polymers, metal stack materials, etch stop layers, and/or other residue from a surface of the microelectronic device.
• the removal compositions may effectively remove low-k dielectric material from one side of the microelectronic device while concurrently removing polymer and other residue from the other side of the microelectronic device.
• the removal compositions of the present aspect of the invention are usefully employed to remove material selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof from rejected microelectronic device structures, including wafers comprising silicon, for recycling and/or reuse of said structures.
• the removal compositions of the invention satisfy the wafer reclamation requirements, including less than 50 particles at 0.12 ⁇ m, a total thickness variation less than the industry standard of 5 ⁇ m, and/or a metal surface contamination of less than I xIO 10 atoms cm "2 .
• an additional chemical mechanical polishing (CMP) step i.e., to planarize the substrate subsequent to the wet removal of the materials, may not be needed to planarize the front-side and backside of the wafer before reuse.
• the parameters of the CMP step may be altered such that the energy requirements are substantially reduced, e.g., the length of time of the polish is shortened, etc.
• the TTV is less than 3%, more preferably less than 1% and most preferably less than 0.5%, subsequent to the removal of the materials from the microelectronic device substrate.
• any of the removal compositions disclosed herein may be used during (CMP) processes, i.e., to planarize copper and remove barrier layer materials, to accelerate the removal of CDO and other low-k dielectric materials, as readily determinable by one skilled in the art.
• CMP chemical vapor deposition
• the removal composition preferably further includes at least one copper passivator species.
• the removal compositions of the invention may be diluted with a solvent such as water and used as a post-chemical mechanical polishing (CMP) composition to remove post-CMP residue including, but not limited to, particles from the polishing slurry, carbon-rich particles, polishing pad particles, brush deloading particles, equipment materials of construction particles, copper, copper oxides, and any other materials that are the by-products of the CMP process.
• CMP post-chemical mechanical polishing
• the concentrated removal compositions may be diluted in a range from about 1:1 to about 1000:1 solvent to concentrate, wherein the solvent can be water and/or organic solvent.
• any of the removal compositions disclosed herein may be buffered to a pH in a range from about 5 to about 8, preferably about 5.5 to about 7, to minimize corrosion of the materials of construction in the fab, e.g., steel drainage systems and other tools, as readily determinable by one skilled in the art.
• Contemplated buffering species include, but are not limited to organic quaternary bases, alkali bases, alkaline earth metal bases, organic amines, alkoxides, amides, and combinations thereof.
• the buffering species may include benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, benzyltributylammonium hydroxide, dimethyldiethylammonium hydroxide, tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide, tetrapropyl ammonium hydroxide, tetrabutyl ammonium hydroxide, ammonium hydroxide, potassium hydroxide, cesium hydroxide, rubidium hydroxide, alkyl phosphonium hydroxides, and derivatives thereof, Aniline, Benzimidazole, Benzylamine, 1- Butanamine, «-Butylamine, Cyclohexanamine, Diisobutylamine, Diisopropylamine, Dimethylamine, Ethanamide, Ethanamine, Ethylamine, Ethylenediamine, 1-Hexanamine, 1 ,6-Hexanedia
• the removal compositions of the invention are formulated in the following embodiments, wherein all percentages are by weight, based on the total weight of the formulation:
• HF about 0.01% to about about 5% to about 35% about 10% to about 25%
• 50% organic solvent(s) about 20% to about about 10% to about 65% about 15% to about 30% or 70% about 50% to about 60% water about 0.01% to about about 10% to about 80% about 20% to about 80% 80% oxidizing agent(s) O to about 10% about 0.01 to about 7% about 0.1 to about 5% chelating agent(s) 0 to about 5% about 0.01% to about 1% about 0.01% to about 0.5%
• the removal compositions of the invention are easily formulated by simple addition of the respective ingredients and mixing to homogeneous condition. Furthermore, the removal compositions may be readily formulated as single-package formulations or multi-part formulations that are mixed at the point of use. The individual parts of the multi-part formulation may be mixed at the tool or in a storage tank upstream of the tool. The concentrations of the respective ingredients may be widely varied in specific multiples of the removal composition, i.e., more dilute or more concentrated, in the broad practice of the invention, and it will be appreciated that the removal compositions of the invention can variously and alternatively comprise, consist or consist essentially of any combination of ingredients consistent with the disclosure herein.
• one aspect of the invention relates to concentrated formulations of the compositions described herein with low amounts of water and/or solvent, or alternatively without water and/or solvent, wherein water and/or solvent may be added prior to use to form the removal compositions of the invention.
• the concentrated formulations may be diluted in a range from about 1 : 10 to 10:1 solvent to concentrate, wherein the solvent can be water and/or organic solvent.
• another aspect of the invention relates to a kit including, in one or more containers, one or more components adapted to form the removal compositions of the invention.
• the kit may include, in one or more containers, at least one amine, hydrofluoric acid, optionally at least one organic solvent, optionally at least one chelating agent, optionally at least one additional acid, and optionally water for combining at the fab.
• the kit may include at least one amine, hydrofluoric acid, at least one organic solvent, and at least one additional acid, for combining with the water and/or organic solvent at the fab.
• the kit may include at least one amine, hydrofluoric acid, water, and at least one additional acid, for combining with the water and/or organic solvent at the fab.
• the kit may include, in one or more containers, at least one amine-hydrogen fluoride salt, additional hydrofluoric acid, at least one organic solvent, and optionally at least one additional acid, for combining with water and/or organic solvent at the fab.
• the kit may include, in one or more containers, hydrofluoric acid, at least one organic solvent, optionally at least one chelating agent, and optionally at least one organic acid, for combining with the water and/or organic solvent at the fab. It should be appreciated that the kit may include any of the components of the foregoing embodiments, in any combination, as readily determined by one skilled in the art.
• the containers of the kit should be chemically rated to store and dispense the component(s) contained therein.
• the containers of the kit may be NOWPak® containers (Advanced Technology Materials, Inc., Danbury, Conn., USA).
• the removal compositions may be formulated as foams, fogs, subcritical or supercritical fluids (i.e., wherein the solvent is CO 2 , etc., instead of water and/or organic solvent(s)).
• the removal compositions dissolve materials selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof from the microelectronic device substrate (i.e., bare silicon, polysilicon) rather than delaminate said material therefrom. Dissolution has the advantage of minimizing the generation of particulate matter that may subsequently settle on said substrate as well as substantially eliminating clogging of the removal equipment.
• the underlying wafer device remaining following the removal process using the compositions of the invention is substantially smooth and undamaged.
• the invention relates to methods of removal of materials selected from the group consisting of low-k dielectric layers, etch stop layers, metal stack materials, and combinations thereof from a microelectronic device having said layers thereon using the removal compositions described herein.
• low-k dielectric materials may be removed while maintaining the integrity of the underlying polysilicon, bare Si, etch stop layers (e.g., SiCN, SiCO, SiC, SiON, SiGe, SiGeB, SiGeC, AlAs, InGaP, InP, InGaAs,), and metal stack materials.
• low-k dielectric layers and metal stack materials may be removed while maintaining the integrity of the underlying polysilicon, bare Si layers, and/or etch stop layers (e.g., SiCN, SiCO, SiC, SiON, SiGe, SiGeB, SiGeC, AlAs, InGaP, InP, InGaAs,).
• etch stop layers e.g., SiCN, SiCO, SiC, SiON, SiGe, SiGeB, SiGeC, AlAs, InGaP, InP, InGaAs,.
• low-k dielectric layers, etch stop layers and metal stack materials may be removed while maintaining the integrity of the underlying polysilicon and bare Si layers.
• the invention relates to methods of removal of low-k dielectric layers from one side of the microelectronic device and polymer or other residues from the other side of the microelectronic device.
• the removal composition is applied in any suitable manner to the rejected microelectronic device having material to be removed thereon, e.g., by spraying the removal composition on the surface of the device, by dipping (in a volume of the removal composition) of the device including the low-k dielectric material, by contacting the device with another material, e.g., a pad, or fibrous sorbent applicator element, that has said removal composition absorbed thereon, by contacting the device including the material to be removed with a circulating removal composition, or by any other suitable means, manner or technique, by which the removal composition is brought into removal contact with the material to be removed.
• batch or single wafer processing is contemplated herein.
• the removal process using the removal compositions may include a static clean, a dynamic clean, or sequential processing steps including dynamic cleaning, followed by static cleaning of the device in the removal composition, with the respective dynamic and static steps being carried out alternatingly and repetitively, in a cycle of such alternating steps.
• the removal compositions may be used with a large variety of conventional cleaning tools, including Verteq single wafer megasonic Goldfinger, OnTrak systems DDS (double-sided scrubbers), Laurell spin-spray tools, SEZ single wafer spray rinse, Applied Materials Mirra-MesaTM /Reflexion TM/Reflexion LKTM, and Megasonic batch wet bench systems.
• the removal compositions of the present invention are usefully employed to remove material selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof from rejected microelectronic device structures for recycling and/or reuse of said structures.
• the removal compositions may be used during chemical mechanical polishing processes to accelerate the removal of CDO and other low-k dielectric materials or post- CMP processes to remove post-CMP residue material.
• compositions of the present invention by virtue of their selectivity for such material(s), relative to other materials that may be present on the microelectronic device structure and exposed to the removal composition, such as polysilicon, bare Si, etc., to achieve at least partial removal of the material(s) in a highly efficient manner.
• the removal composition typically is contacted with the device structure for a time of from about 30 seconds to about 60 minutes, more preferably about 75 sec to about 5 min, the preferred time being dependent on the thickness of the Iayer(s) to be removed, at temperature in a range of from about 2O 0 C to about 90 0 C, preferably about 25 0 C to about 6O 0 C, most preferably about 25 0 C to about 50 0 C.
• the contacting time may be in a range of from about 5 minutes to about 3 hours at temperature in a range of from about 25 0 C to about 80°, depending on the thickness of the etch stop layer.
• Such contacting times and temperatures are illustrative, and any other suitable time and temperature conditions may be employed that are efficacious to at least partially remove the material(s) from the device structure, within the broad practice of the invention.
• "at least partial dissolution” corresponds to at least 90% dissolution removal of material, preferably at least 95% dissolution removal of material. Most preferably, at least 99% of the material is dissolvably removed using the compositions of the present invention.
• the removal composition is readily removed from the microelectronic device to which it has previously been applied, e.g., by rinse, wash, or other removal step(s), as may be desired and efficacious in a given end use application of the compositions of the present invention.
• the microelectronic device may be rinsed with deionizfid water.
• the microelectronic device may be dried with nitrogen gas or SEZ (spin process technology).
• the present invention relates to methods of manufacturing an article comprising a microelectronic device, said method comprising contacting a rejected microelectronic device structure with the removal compositions of the present invention for sufficient time to at least partially remove material selected from the group consisting of low-k dielectric material, etch stop layers, metal stack materials, and combinations thereof from the microelectronic device structure to yield a reusable microelectronic device structure, and optionally further comprising applying one or more layers to the reusable microelectronic device structure, including at least one low-k dielectric material layer, in a subsequent multi-layer microelectronic device manufacturing process and incorporating said microelectronic device into said article.
• the wet bench tools in the art consist of two baths - one for the removal composition and one for rinsing the device wafer subsequent to immersion in the removal composition.
• the pH of the rinse bath can become very acidic following immersion of the device wafers having fluoride-containing removal compositions.
• a solution having high fluoride concentrations (and high organic solvent concentrations) may cause significant disposal problems. Accordingly, a process is needed to ensure that the rinse water does not become too acidic.
• the present invention further relates to the incorporation of a third bath in the wet bench tool, specifically a neutralizing bath for use subsequent to the removal composition bath but prior to the rinse bath, said bath being useful for neutralizing the high fluoride content of the removal composition that remains on the device wafer following immersion therein.
• a third bath in the wet bench tool specifically a neutralizing bath for use subsequent to the removal composition bath but prior to the rinse bath, said bath being useful for neutralizing the high fluoride content of the removal composition that remains on the device wafer following immersion therein.
• the present invention broadly relates to a method of at least partially removing low-k dielectric material from the microelectronic device structure using the removal compositions of the invention, neutralizing the wafer surface using a buffer rinse step and rinsing the neutralized wafer with water.
• the present aspect of the invention relates to a method of removing low-k dielectric material from a microelectronic device having said low-k dielectric material thereon, said method comprising: contacting the microelectronic device with a removal composition for sufficient time to at least partially remove said low-k dielectric material from the microelectronic device, wherein the removal composition includes hydrofluoric acid, and at least one amine species, and wherein the pH of a 20:1 dilution of the removal composition in water is in a range from about 2.5 to about 4.5;
• the neutralizing compositions include at least one buffering species wherein the pH of the neutralized removal composition is in a range from about 5 to about 9, more preferably in a range from about 6 to about 8, and most preferably about 7.
• Buffering species contemplated herein include, but are not limited to, commercial color-coded buffer solutions or customized solutions including bases such as hydroxides, carbonates, phosphates, diphosphates, etc., and base/salt mixtures.
• Bare Si substrates having blanketed BD materials thereon were statically soaked in concentrated Formulation A for 2 min to 5 min at 40 0 C to 6O 0 C as indicated in Table 1.
• the BD material layers were characterized by the method of depositing the BLACK DIAMONDTM material as well as the thickness of the BD layers.
• the first bare Si substrate had a blanketed BLACK DIAMONDTM layer deposited using the proprietary BLACK DIAMONDTM process and had a thickness of approximately 6,5O ⁇ A (hereinafter BDTM).
• the second bare Si substrate had a blanketed BD derivative material deposited using a proprietary deposition process and had a thickness of approximately 13,OO ⁇ A (hereinafter BDDl).
• the third bare Si substrate had a blanketed BD derivative material deposited using another proprietary deposition process and had a thickness of approximately 12,OO ⁇ A (hereinafter BDD2).
• Table 1 Results of static soak of BD materials in diluted Formulation A.
• Blanketed polysilicon was statically soaked in Formulation A for 30 minutes at various temperatures and the etch rate of the polysilicon determined. The results are summarized in Table 2 hereinbelow.
• Table 3 Results of static soak of bare Si and BD materials in Formulation A.
• Example 1 were statically soaked in concentrated Formulation B for 1 min to 2 min at 30 0 C to 50 0 C as indicated in Table 5.
• the results of the static soak are summarized in Table 5 hereinbelow, whereby a "yes” denotes that the specific BD material was substantially dissolved in the composition at the specified temperature during the soak for the specified time.
• Example 6 Blanketed polysilicon was statically soaked in Formulation B for 30 minutes at various temperatures and the etch rate of the polysilicon determined. The results are summarized in Table 6 hereinbelow.
• Example 1 were statically soaked in concentrated Formulation C for 1 min to 2 min at 30 0 C to 50 0 C as indicated in Table 9.
• the results of the static soak are summarized in Table 9 hereinbelow, whereby a "yes” denotes that the specific BD material was substantially dissolved in the composition at the specified temperature during the soak for the specified time.
• Blanketed polysilicon was statically soaked in Formulations I-O for 30 minutes at various temperatures and the etch rate of the polysilicon determined. The results are summarized in Table 13 hereinbelow.
• Ta ble 13 Results of static soak of ol silicon in Formulations I-O.
• Bare Si substrates having blanketed BD materials thereon (as described in Example 1) were statically soaked in concentrated Formulation CC for 1 min at 30 0 C to 50 0 C as indicated in Table
• Table 18 Results of static soak of BD materials in diluted Formulation CC.
• the BD materials were etched from the surface of the substrate and were not dependent on the process conditions evaluated, including time of soaking, the temperature, or the thickness of the BD material.
• Blanketed polysilicon (initial thickness of approximately 970 A) was statically soaked in
• Table 20 Results of static soak of bare Si and BD materials in Formulation CC.
• Silicon substrates having a blanketed CORALTM layer having a thickness of approximately 22,000 ⁇ 1,000 A thereon were statically soaked in Formulation CC for 2 min at 40 0 C. Following immersion for the specified time, the substrate was rinsed with DI water, dried, and the amount of CORALTM removed and the etch rate determined using a Nanospec. It was determined that 22,042 A of CORALTM was removed and thus the etch rate was 11,021 A min '1 . It can be concluded herein that Formulation CC provides excellent CORAL etch rates at relatively low temperatures.
• a silicon substrate having a blanketed CORALTM layer was statically soaked in Formulation CC for 200 minutes at 60 0 C to mimic extreme soaking conditions. Following immersion, the sample was removed from the static soak bath, rinsed, dried and the Atomic Force Microscopic (AFM) surface roughness determined. The RMS roughness (5 ⁇ m scan) of the bare Si after processing was determined to be 0.845 nm.
• Formulation CC efficiently removes the many low-k dielectric variations, with the overall efficiency dependent on the removal temperature chosen. Importantly, Formulation CC did not compromise copper materials that were exposed to said formulation.
• Table 25 Results of static soak of film layers in Formulation CC.
• the Ta, TaN, and TiN metal stack materials can be removed using the formulation of the present invention, however, copper material was not readily removed at the temperatures investigated.
• 40 g of Formulation CC was mixed with 4 g of 30 % hydrogen peroxide and the low-k and metal stack materials immersed therein (see Formulation II herein).
• the etch rate of the low-k dielectric materials was unchanged following the inclusion of H 2 O 2 in Formulation CC, however, the etch rate of the copper was immeasurable because the copper layer was etched so rapidly.
• the etch rate of the TiN was increased when immersed in Formulation II.
• the first experiment included cleaning a device wafer with Formulation CC for 3 minutes at 50 0 C followed by rinsing said wafer in a deionized (DI) water bath for 1 min, wherein the volume of Formulation CC was the same as the volume of DI water in the rinse bath. The pH of the DI water was measured before and after the rinsing step.
• DI deionized
• the second experiment included immersion of the device wafer in formulation CC for 3 minutes at 50 0 C, followed by immersion of the device wafer in the neutralizing buffer bath for 1 minute, and lastly immersion in the DI water rinse bath for 1 minute.
• the neutralizing buffer bath had a pH of approximately 7 prior to immersion therein.
• the volume of removal composition bath, neutralizing buffer bath and rinse bath is approximately the same.
• the pH of the DI water bath and the neutralizing buffer bath were measured before and after the rinse step. The results are reported in Table 26.
• Table 26 H of baths followin immersion of device wafers therein.
• the third experiment included immersion of the device wafer in formulation CC for 3 minutes at 5O 0 C, followed by immersion of the device wafer in the neutralizing buffer bath for 1 minute, and lastly immersion in the DI water rinse bath for 1 minute.
• the neutralizing buffer bath had a pH of approximately 10. Similar to the first experiment, the volume of removal composition bath, neutralizing buffer bath and rinse bath is approximately the same. The pH of the DI water bath and the neutralizing buffer bath was measured before and after the rinse step and the results reported in
• Table 27 pH of Dl water following serial immersion of six samples.
• the buffer bath aids in maintaining the DI water bath pH at about pH 7 even after multiple, serial rinsing steps.
• Formulation CC was buffered with tetramethylammonium hydroxide (TMAH), or monoethylamine (MEA) and the resulting solutions had measured pH values of 6. Unfortunately, the solutions underwent phase separation and were discarded. Formulation CC was then buffered with triethylamine (TEA) to form a solution having a pH of 7.4 and a solution having a pH of 5.5. In both cases, the solutions including TEA remained in one phase and blanketed samples of CORAL®, BD and poly-Si were immersed in each solution at 50 0 C and the etch rates of each determined using a NanoSpec. In each case, buffered formulation CC displayed an unacceptably fast etch rate of the underlying silicon-containing layer (Si damage was observed) and an unacceptably slow etch rate of the low-k dielectric material.
• TMAH tetramethylammonium hydroxide
• MEA monoethylamine
• HF in Formulation CC was replaced with approximately 20 wt. % tetrabutylammonium fluoride (TBAH) or approximately 20 wt. % borofluoric acid. Blanketed samples of CORAL®, BD and poly-Si were immersed in each solution at 50 0 C and the etch rates of each determined using a NanoSpec. It was concluded that in formulation CC, the best fluoride source remains HF.
• TBAH tetrabutylammonium fluoride
• Hydroxide-based formulations having a pH of about 13.7 were investigated as an alternative to fluoride-based removal compositions. Blanketed samples of CORAL®, BD and poly-Si were immersed in each solution at 5O 0 C and the etch rates of each determined using a NanoSpec. It was concluded that acidic, fluoride-based formulations are superior to hydroxide-based formulations at removing low-k dielectric material from the surface of the microelectronic device.
• Formulation CC was diluted with water, diethylene glycol monobutyl ether (BC) or 1- phenoxy-2-propanol (PPh) in order to decrease the overall HF concentration (1 part formulation CC to x parts diluting solvent). These solutions would have the advantage of having low HF concentrations and as such, could be disposed of by incineration. Blanketed samples of CORAL®, BD and poly-Si were immersed in each solution at the specified temperature for the specified length of time and the etch rates of each determined using a NanoSpec. The results using the formulation diluted with water, BC and PPh are shown in Tables 28, 29 and 30, respectively. Table 28: Etch rates in A min ⁇ ' of sam les immersed in formulation diluted with water at 60 0 C.
• BC diethylene glycol monobutyl ether
• PPh 1- phenoxy-2-propanol
• the 1 :1 and 1 :2 dilutions with PPh both had an acceptable low-k dielectric etch rate and a negligible underlying silicon-containing layer etch rate.
• these compositions diluted with PPh have a much lower concentration of HF than formulation CC and as such, disposal issues are reduced.
• a three-step process of removing low-k dielectric material from the surface of a microelectronic device was investigated.
• BD wafers were immersed in a 20 wt. % HF solution for 1 min or 5 min at 50 0 C. In both cases, BD residue was visually observed on the wafer following immersion. Thereafter, the wafers were immersed in a 97.5 wt. % BC/2.5 wt. % sulfolane composition for 1 min or 5 min at 50 0 C. Again, BD residue was visually observed on the wafer. Thereafter the wafer was immersed in water, dried and the surface imaged using SEM. The micrographs clearly illustrated that BD residues remained on the surface of the wafer at the conclusion of the three-step process which indicates that the three-step process as described herein using the components of Formulation CC is not a viable option.
• Formulation DD represents a variation of Formulation CC having a lower organic solvent concentration and a higher fluoride concentration, so that the formulation had a lower COD count while still having a high low-k dielectric etch rate and a low underlying layer etch rate.
• Formulation DD provided a high low-k dielectric removal rate and a low poly-Si removal rate, and would be a viable option when high concentrations of HF are acceptable.
• Formulation EE represents a variation of Formulation DD having a lower fluoride concentration and the same organic solvent concentration, as introduced hereinbelow.
• Formulation EE provided a high low-k dielectric removal rate and a low poly-Si removal rate, and would be a viable formulation for the removal of low-k dielectric materials from microelectronic devices for recycling of same.
• formulation EE removes Ta and TiN after immersion for 10 min at 60 0 C, disadvantageous ⁇ with delamination, but cannot dissolve TaN or Cu under the same conditions.
• formulation EE can remove BD and CORAL without substantially damaging the underlying device substrate, e.g., poly-Si. That said, formulation EE does not readily remove metal films.
• oxidizing agents such as hydrogen peroxide and nitric acid may be added to the formulations to enhance the concurrent removal of metal films from the surface of the device substrate without damaging said substrate.
• Formulations JJ and KK represents variations of formulation CC including oxidizing agents.
• the oxidizing agent may be introduced to the composition at the manufacturer, prior to introduction of the composition to the device wafer, or alternatively at the device wafer, i.e., in situ. It is further contemplated that in addition to oxidizing agent(s), other components may be added to the composition to dilute, maintain and/or increase the concentration of other components in the composition.
• chelating agents were added to the formulations including oxidizing agents.
• Chelating agents contemplated herein include ethylenediaminetetraacetic acid (EDTA), (l,2-cyclohexylenedinitrilo)tetraacetic acid (CDTA), monoethanolamine (MEA), and acetylacetone (acac).
• EDTA ethylenediaminetetraacetic acid
• CDTA l,2-cyclohexylenedinitrilo)tetraacetic acid
• MEA monoethanolamine
• acetylacetone acac
• Formulation OO displayed the most favorable results whereby the low-k and metal materials were readily removed from the device substrate and no Cu re-deposition or precipitation was observed on the processed substrate.
• separate tests relating to the addition of chelating agents to formulation EE (i.e., devoid of oxidizing agent) and the static immersion of blanketed Cu wafers therein revealed that the Cu would not dissolve in a composition including chelating agents but not oxidizing agents.
• formulation QQ stored at room temperature for 49 days still removed ⁇ 5000 A copper in 10 sec and a ⁇ 9000 A three-layer film including copper/TaN/low-k in 1 minute.
• the same formulation stored at 40 0 C for 35 days removed ⁇ 5000 A copper in 10 sec and a ⁇ 9000 A three- layer film including copper/TaN/low-k in 1 minute.
• Formulations AA, EE and FF attack the metal films and barrier layer materials.
• concentration of HF and butyl carbitol is decreased (formulation FF)
• the etch rate of copper increased while the etch rate of TaN, Ta and TiN all decreased.
• a composition having a low concentration of HF plus barrier layer inhibiting agents will reduce the etch rate of the barrier layer materials, especially Ta and TiN.
• Formulations GG and HH were 1.42 A min “1 and 0.54 A min “1 , respectively.

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