Classifications

• • 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
  • H10P50/286—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of organic materials
  • H10P50/287—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of organic materials by chemical means
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/37—Polymers
  • C11D3/3746—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C11D3/3757—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions
  • C11D3/3765—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions in liquid compositions
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/26—Processing photosensitive materials; Apparatus therefor
  • G03F7/42—Stripping or agents therefor
  • G03F7/422—Stripping or agents therefor using liquids only
  • G03F7/425—Stripping or agents therefor using liquids only containing mineral alkaline compounds; containing organic basic compounds, e.g. quaternary ammonium compounds; containing heterocyclic basic compounds containing nitrogen
• • 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
  • H10P50/68—Wet etching of insulating materials
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/10—Objects to be cleaned
  • C11D2111/14—Hard surfaces
  • C11D2111/22—Electronic devices, e.g. PCBs or semiconductors

Definitions

• the present invention relates to a composition for photoresist stripping. Particularly, the present invention relates to a composition for post-ion implantation photoresist stripping.
• Ion implantation is one of the key processes in the fabrication of semiconductor devices. Dopant ions such as boron, phosphorus or arsenic are created from a high purity gas source and implanted in a semiconductor substrate. Each doped atom creates a charge carrier, either hole or electron and thus modifies the conductivity of the semiconductor device in its vicinity. Ion implantation is commonly applied to the source/drain junction and the channel to achieve desired electrical characteristics of the devices to be produced.
• a substrate e.g., silicon wafer
• a positive-tone photoresist is coated on the substrate.
• an organic photoresist mask is formed.
• dopants penetrate into the exposed (unmasked) surface of the substrate as well as the photoresist mask.
• the dopants may react with the photoresist mask to form a relatively nonporous layer, which is commonly known as a "crust.”
• the photoresist mask is then removed by a stripping process.
• Typical post-ion implantation stripping is done by a dry plasma ashing followed by a wet piranha clean (which uses a mixture of sulfuric acid and hydrogen peroxide as clean agents) and a marangoni dry.
• a wet piranha clean which uses a mixture of sulfuric acid and hydrogen peroxide as clean agents
• a marangoni dry is widely used in the semiconductor industry, some drawbacks such as long process time and damage to silicon substrates have been noted. Silicon substrate damage such as sili- con loss has become a key issue as the critical dimension shrinks to 45nm and below. Silicon loss of greater than 3OA may result in undesirable dopant out diffusion and cause device malfunction. For these reasons, the typical process for post-ion implantation stripping process is no longer acceptable and there is need for a new process.
• U.S. Patent No. 6,524,936 entitled to Hal- lock et al. discloses a method which exposes a wafer under UV radiation of 200 nm to 400 nm and at least 100 mJ/cm2 prior to conventional wet or dry stripping processes.
• U.S. Patent No. 5,811 ,358 entitled to Tseng et al. a three-step procedure is disclosed. The substrate is first stripped with an oxygen and nitrogen/hydrogen plasma at a low temperature ( ⁇ 220°C) to minimize the photoresist solvent popping problem.
• Photoresist stripping compositions are disclosed in numerous prior art.
• U.S. Patent No. 6,551 ,973 entitled to Moore discloses a stripping composition comprising benzyl-trimethylammonium hydroxide (BTMAH) and a solvent system comprising alkylsulfoxide and optionally a glycol co-solvent, corrosion inhibitor and non- ionic surfactant for removing polymeric organic substances from metalized inorganic substrates.
• BTMAH benzyl-trimethylammonium hydroxide
• solvent system comprising alkylsulfoxide and optionally a glycol co-solvent, corrosion inhibitor and non- ionic surfactant for removing polymeric organic substances from metalized inorganic substrates.
• U.S. Publication No. 2007/0099805 to Phenis et al. a stripper solution comprising dimethyl sulfoxide and a quaternary ammonium hydroxide and an alka- nolamine is disclosed.
• One of the objects of the invention is to provide a substantially water-free photoresist stripping composition which is useful in removing the photoresist after ion implantation process.
• the composition of the present invention comprises:
• composition is substantially water-free.
• the amine is a quaternary ammonium hydroxide.
• the amine is ben- zyl-trimethylammonium hydroxide (BTMAH).
• the amine is a tetramethylammonium hydroxide (TMAH).
• Another object of the present invention is to provide a method for post-ion implantation stripping.
• the method comprises the steps of:
• Figure 1 is a schematic flow chart comparing typical post-ion implantation stripping with the process of the present invention.
• Figure 2 is a schematic diagram of possible mechanisms in a stripping process.
• the first object of the present invention is to provide a photoresist stripping composition capable of removing photoresist from a substrate after ion implantation.
• the stripping composition of the present invention comprises:
• composition is substantially water-free.
• the amine in the composition of the present invention can break down the polymeric frameworks of the cured photoresist and lift off fragments of the cured photoresist.
• Suitable primary, secondary, tertiary or quaternary amines can be used in the composition of the present invention.
• Suitable primary amines include, but are not limited to, ethanolamine (MEA), N-methylethanolamine (NMEA), cyclohexylamine and hydroxylamine (HA).
• Suitable secondary amines include, but are not limited to, diethylhydroxyliamine, diethylamine and quinoline.
• Suitable tertiary amines include, but are not limited to, dimethylethanolamine and trimethylamine.
• Suitable quaternary amines include, but are not limited to, tetramethylammonium hydroxide (TMAH), ben- zyl-trimethylammonium hydroxide (BTMAH), tetraethylammonium hydroxide (TEAH) and tetrabutylammonium hydroxide (TBAH).
• TMAH tetramethylammonium hydroxide
• BTMAH ben- zyl-trimethylammonium hydroxide
• TEAH tetraethylammonium hydroxide
• TBAH tetrabutylammonium hydroxide
• Preferred amines are quaternary ammonium hydroxides.
• BTMAH and TMAH are surprisingly effective and thus are most preferred.
• the amount of amine in the composition of the present invention can vary from 1 to 10 wt%, preferably 1 to 4 wt%.
• the organic solvent A and co-solvent of the present invention function differently.
• the organic solvent A of the present invention is capable of removing photo- resists from the substrate by lift-off and cutting mechanisms, which are shown as (X) in Figure 2.
• Using solvent A alone without a co-solvent can lift off photoresists from the substrate, but the stripper solution then becomes turbid due to the suspended photoresist fragments in the solution.
• the photoresist fragments will decrease the load capacity of the stripping composition and contaminate the substrate as well as the equip- ment.
• the co-solvent of the present invention is less effective in lifting photoresists from a substrate, but can dissolve photoresist fragments so as to increases the load capacity of the stripping composition.
• the co-solvent alone cannot completely remove the photoresist from a substrate and some photoresist residues, especially the "crust," will remain on the substrate.
• the mechanism of the co-solvent is shown as (Y) in Figure 2.
• the composition of the present invention properly combines a solvent A and a co-solvent to achieve excellent stripping performance.
• the mechanism is schematically shown as (Z) in Figure 2.
• Solvent A and the co-solvent must be carefully selected.
• a suit- able solvent A and the co-solvent should have a flash point higher by at least 1O 0 C, preferably 3O 0 C, than the process temperature and a boiling point at least 4O 0 C higher than the process temperature.
• the melting point should be lower than room temperature and preferably lower than O 0 C to avoid crystallization during storage or shipping. Nevertheless, if a single solvent does not have all of the above physical properties, for example DMSO has a melting point of 18.5 0 C but is particularly effective at lifting off or dissolving implanted photoresists, it can be mixed with other suitable solvent(s) to meet the requirements.
• a suitable co-solvent is selected from alcohols, including primary, secondary and tertiary alcohols, such as isopropyl alcohols, isobutyl alcohols, sec-butyl alcohols, isopentyl alcohols, tert-pentyl alcohols, ethylene glycol (EG), propylene glycol, 1 ,2- propanediol, 1 ,3-propanediol, 1 ,2,3-propanetriol and 1-amino-2-propanol; esters, such as isopropyl acetate and ethyl acetoacetate; amines containing a hydroxy group, such as triethanol amine, ethanolamine (MEA), formamide, dimethylacetamide (DMAC), 2- (methylamino_ethanol (NMEA), and N-ethyldiisopropylamine; or a combination thereof.
• alcohols including primary, secondary and tertiary alcohols, such as isopropyl alcohols, iso
• DMSO, NMP, benzyl alcohol, propanol, butyldiglycol, pentanol, N,N-dimethylethanol amine, benzaldehyde or a mixture thereof is preferred for use in the present invention as solvent A.
• DMSO, NMP, benzyl alcohol, butyldiglycol and a mixture thereof are more preferred.
• Ethylene glycol, 1 ,2-propanediol, 1-amino-2-propanol, triethanol amine, MEA, isopropyl acetate or a mixture thereof is preferred for use in the present invention as a co-solvent and ethylene glycol, triethanol amine, MEA or a mixture thereof is more preferred.
• the amount of the solvent A and co-solvent basically ranges from 90 to 99 wt% of the composition, if no other additives are added.
• the ratio of the solvent A to co-solvent is not critical.
• the stripping composition of the present invention can optionally contain additives such as chelating agents and surfactants.
• Suitable chelating agents include, but are not limited to, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepen- taacetic acid (DTPA) and 2,4-pentanedione.
• Suitable surfactants include, but are not limited to, non-ionic alkoxylated alcohols, nonyl-phenols and nonyl-ethoxylates.
• the amount of each additive can vary depending on needs and can be decided by a skilled person in view of prior art. Preferably, the total amount of additives is less than about 1 wt% of the composition.
• the stripping composition of the present invention is substantially water-free, that is, the water content must be less than 3 wt%, preferably less than 1 wt%, and more preferably less than 0.5 wt% so as to prevent damage to a silicon substrate. Silicon loss is highly correlated with the water content of the composition.
• Another object of the present invention is to provide a wet process for post- ion implantation.
• the method comprises the steps of:
• the stripping process of the present invention does not require dry plasma ashing, so it is advantageous in reduction of cycle time and energy consumed.
• the method of the present invention can be performed in any suitable equipment such as conventional wet bench or cleansers.
• the contact of the substrate with the composition can be done by any suitable conventional means such as immer- sion, rinsing, spraying and jetting.
• the method is performed in a wet bench.
• the process can be conducted at a temperature of 25 0 C to 9O 0 C, preferably 4O 0 C to 8O 0 C, and more preferably 6O 0 C to 8O 0 C.
• the temperature is much lower than the process temperature of piranha clean, which is normally 12O 0 C to 14O 0 C. It is believed that elevated temperature increases silicon loss of a substrate, so a lower temperature is beneficial.
• implanted photoresists can be completely removed from a substrate in 20 min to 2hr. Actual time depends on the types of photoresists, equipment used and process conditions.
• Table 2 shows that among the usedamines, TMAH shows surprisingly effective photoresist stripping performance at the given process conditions. It should be noted that other amines are also capable of removing photoresists, although their performance is not as good as TMAH and BTMAH.
• Table 3 shows that the process window for TMAH is broader than BTMAH.
• BTMAH 60min at 7O 0 C is required to complete the stripping.
• TMAH 60min at 6O 0 C is required.
• elevated temperature is disadvantageous because it increases the damage to silicon substrate.
• Table 5 shows the performance of the embodiments of the present invention. It should be noted that the ratio of solvent A to co-solvent is not critical.

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• General Physics & Mathematics (AREA)
• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Cleaning Or Drying Semiconductors (AREA)
• General Chemical & Material Sciences (AREA)

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• 2010
  • 2010-07-26 MY MYPI2012000352A patent/MY185453A/en unknown
  • 2010-07-26 SG SG10201404328QA patent/SG10201404328QA/en unknown
  • 2010-07-26 CN CN201080033645.5A patent/CN102473638B/zh active Active
  • 2010-07-26 US US13/387,787 patent/US9484218B2/en active Active
  • 2010-07-26 WO PCT/EP2010/060762 patent/WO2011012559A2/en not_active Ceased
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  • 2010-07-26 EP EP10736715.3A patent/EP2460177B1/en active Active
  • 2010-07-26 KR KR1020127005545A patent/KR101746879B1/ko active Active
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• 2012
  • 2012-01-24 IL IL217708A patent/IL217708A/en active IP Right Grant

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