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
  • H10P70/00—Cleaning of wafers, substrates or parts of devices
  • H10P70/10—Cleaning before device manufacture, i.e. Begin-Of-Line process
  • H10P70/15—Cleaning before device manufacture, i.e. Begin-Of-Line process by wet cleaning only
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts

Definitions

• the invention relates to a method for removing silicon dioxide residues from a semiconductor surface after polishing with a silicon dioxide-containing polishing agent.
• polishing slurry Polishing with silica Ahren an example of a typical Polierver f.
• a polishing slurry containing an abrasive colloidal silicon dioxide, sodium dichloroisocyanurate as an oxidizing agent and sodium carbonate as a basic component are used.
• the pH of the polishing slurry is below 10. After polishing, it is necessary to clean the polished surface to remove the polishing slurry and other surface contaminants with a minimum of chemical or mechanical surface damage.
• the object of the invention is to provide an environmentally friendly, safe and effective method for removing silicon dioxide polishing materials while maintaining a clean, hydrophilic, undamaged semiconductor surface.
• the object of the invention is achieved by a method of the type mentioned at the outset, which is characterized in that the semiconductor surface is treated with an aqueous phosphoric acid solution and then rinsed with water and an aqueous ammonium hydroxide solution.
• the semiconductor surface is additionally treated with an aqueous sulfuric acid solution and then rinsed.
• the aqueous silica-based slurry used to polish semiconductor surfaces contains colloidal silica as the abrasive material, an oxidizing agent such as sodium dichloroisocyanurate and a base such as sodium carbonate.
• the surface After polishing the semiconductor surface with the silicon dioxide slurry, the surface is contaminated with a residue of colloidal silicon dioxide, amorphous silicon dioxide, sodium carbonate and residues of the polishing cloth. Rinsing with water alone is not enough to remove the impurities.
• the hydrophobic nature of the surface is converted to a hydrophilic one, which is probably due to the hydrolysis of the siloxane groups on the silicon surface taking place in an acid medium.
• Surface hydrolysis and dissolution are accelerated by a sulfuric acid treatment as shown in Example 1.
• the method allows the semiconductors to be stored prior to cleaning by placing them in a dilute aqueous solution of phosphoric acid without water stains or fog on the semiconductor surface after cleaning.
• Suitable phosphoric acid concentrations in Water is in the range of 10 to 50% by weight, preferably in the range of 20 to 30% by weight.
• the semiconductor substrates are removed from the polishing machine without being allowed to dry. They can then be cleaned immediately or stored in a phosphoric acid cleaning solution for a prolonged period (for example 24 hours) and then easily and effectively cleaned by the process according to the invention to obtain a haze-free surface.
• a phosphoric acid cleaning solution for about 5 to 10 minutes at ambient temperatures (20 to 30 ° C) and then rinsed in water to remove the loosely adhering particles and the phosphoric acid solution.
• the substrates are then preferably treated with a dilute (20 to 30% by weight) aqueous sulfuric acid solution, which brings about the dissolution of any silicon phosphates and favors the surface hydrolysis.
• the sulfuric acid solution can be added to the phosphoric acid solution.
• the water-rinsed substrates are rinsed (immersed or sprayed) with dilute aqueous ammonium hydroxide solution which is about 3 to 5% by weight.
• a complexing agent can also be added to the ammonium hydroxide solution to promote ion removal.
• the semiconductor body is then rinsed in water and cleaned by brushing in water.
• the concentrations are in parts by weight, unless stated otherwise.
• Freshly polished and rinsed silicon wafers are placed in an aqueous 21% phosphoric acid solution for 10 minutes and then removed and rinsed in running deionized water for two minutes.
• the wafers are placed in 20% by weight aqueous sulfuric acid for five minutes, rinsed with deionized water for two minutes, and then rinsed with a 3% aqueous ammonium hydroxide solution for 30 seconds. They are then sprayed with deionized water and spun dry in a hot nitrogen atmosphere. This process is carried out in an automatic rinsing-drying device.
• the wafers are cleaned by brushing or with a felt with deionized water. Examination of the surface under a bright lamp showed that there was no silica or other particulate contaminants.
• the above-mentioned method can be modified in such a way that two steps are eliminated when using an aqueous solution containing 21% by weight phosphoric acid and 20% by weight sulfuric acid in one step. This eliminates the need for separate use of sulfuric acid and the second water rinse.
• Silicon wafers that have been polished with a silicon dioxide polishing slurry and then rinsed with water are removed from the polishing machine. removed and placed in a 20% by weight aqueous phosphoric acid solution at room temperature for five minutes without prior drying.
• the wafers are removed from the solution and rinsed with deionized water for three minutes and then sprayed with an aqueous 3% by weight ammonium hydroxide solution and then with deionized water in a sprayer for 30 seconds and then spun in a hot nitrogen atmosphere.
• the entire rinsing process is carried out in an automatic spray drying machine and takes approximately 10 minutes.
• the wafers are hydrophilic (i.e. water wets the surface). The wafer surfaces are clean and without fog.
• An emission spectrographic analysis on the cleaned wafers shows negligible amounts of Al, Ca, Cr, Cu, Fe, Mg, Na and Ti.
• the described method leads to polished semiconductor surfaces which are clean, hydrophilic and without fog.
• the surfaces are not degraded by the cleaning process and only environmentally friendly and hygienic materials are used in the process.
• the semiconductor materials can be stored in dilute phosphoric acid solution for up to 24 hours before cleaning, without the surface being damaged in any way. Only a light brush cleaning is required to remove any particles from the cleaned surfaces.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Cleaning Or Drying Semiconductors (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Weting (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=25241258

Family Applications (1)

Country Status (4)

Families Citing this family (25)

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• 1977
  • 1977-08-15 US US05/824,382 patent/US4116714A/en not_active Expired - Lifetime
• 1978
  • 1978-07-10 DE DE7878100336T patent/DE2861075D1/de not_active Expired
  • 1978-07-10 EP EP78100336A patent/EP0000701B1/de not_active Expired
  • 1978-07-12 JP JP8410178A patent/JPS5432262A/ja active Granted

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