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EP-3866185-B1 - SEMICONDUCTOR SILICON WAFER CLEANING TREATMENT APPARATUS AND CLEANING METHOD

EP3866185B1EP 3866185 B1EP3866185 B1EP 3866185B1EP-3866185-B1

Inventors

  • IGARASHI, Kensaku

Dates

Publication Date
20260506
Application Date
20190917

Claims (9)

  1. A method for cleaning a semiconductor silicon wafer for cleaning a semiconductor silicon wafer after polishing, the method comprising: an ozone water treatment step after polishing, of immersing, in ozone water, the semiconductor silicon wafer after polishing; a step of performing a first ultrasonic-wave-ozone-water treatment of cleaning the semiconductor silicon wafer at room temperature while immersing in ozone water and applying ultrasonic waves; and a step of performing a second ultrasonic-wave-ozone-water treatment of, after the step of performing the first ultrasonic-wave-ozone-water treatment, pulling out the semiconductor silicon wafer from the ozone water, performing a wafer rotation process of rotating, and cleaning the semiconductor silicon wafer after the wafer rotation process again at room temperature while immersing in ozone water and applying ultrasonic waves; wherein the step of performing the second ultrasonic-wave-ozone-water treatment is performed once or more times, and subsequently, a hydrofluoric acid treatment step of immersing the semiconductor silicon wafer in hydrofluoric acid and an ozone water treatment step of immersing the semiconductor silicon wafer after the hydrofluoric acid treatment step in ozone water are performed.
  2. The method for cleaning a semiconductor silicon wafer according to claim 1, wherein when the step of performing the second ultrasonic-wave-ozone-water treatment is performed "n" times, a rotation angle of the semiconductor silicon wafer in the wafer rotation process is 360°/(1+n).
  3. The method for cleaning a semiconductor silicon wafer according to claim 1 or 2, wherein the step of performing the second ultrasonic-wave-ozone-water treatment is performed twice.
  4. The method for cleaning a semiconductor silicon wafer according to any one of claims 1 to 3, comprising a pure water treatment step of immersing the semiconductor silicon wafer in pure water, wherein the pure water treatment step is performed at least before the hydrofluoric acid treatment step.
  5. The method for cleaning a semiconductor silicon wafer according to claim 4, wherein out of waste liquids produced in the steps, waste liquids of ozone water and pure water are collected and reused.
  6. The method for cleaning a semiconductor silicon wafer according to any one of claims 1 to 5, wherein out of the steps, an ozone water concentration in the steps where ozone water is used is 10 ppm or more.
  7. The method for cleaning a semiconductor silicon wafer according to any one of claims 1 to 6, wherein the semiconductor silicon wafer after polishing is a semiconductor silicon wafer polished using silica as a polishing agent.
  8. An apparatus for cleaning a semiconductor silicon wafer for cleaning a semiconductor silicon wafer after polishing, the apparatus comprising: a first ozone water tank filled with ozone water for immersing, in the ozone water, the semiconductor silicon wafer after polishing; a hydrofluoric acid tank filled with hydrofluoric acid for immersing the semiconductor silicon wafer in the hydrofluoric acid; a second ozone water tank filled with ozone water for immersing, in the ozone water, the semiconductor silicon wafer after immersing in the hydrofluoric acid; an ozone water tank having an ultrasonic wave application means for immersing the semiconductor silicon wafer in ozone water and cleaning while applying ultrasonic waves; the apparatus being characterised in that it comprises: a wafer rotation means for taking the semiconductor silicon wafer out of the ozone water tank having the ultrasonic wave application means and rotating.
  9. The apparatus for cleaning a semiconductor silicon wafer according to claim 8, wherein the ozone water filled in the ozone water tanks has a concentration of 10 ppm or more.

Description

TECHNICAL FIELD The present invention relates to: an apparatus for cleaning a semiconductor silicon wafer; and a method for cleaning a semiconductor silicon wafer. BACKGROUND ART Conventionally, when a wafer having a polishing agent adhered to the wafer surface immediately after polishing is cleaned in a batch (cleaned by dipping), it has been common and necessary to perform a cleaning using SC1 (a mixed solution of ammonia water and hydrogen peroxide water) in order to remove organic matter or silica particles contained in the polishing agent, etc. FIG. 2 is a diagram showing an example of a conventional flow for cleaning a semiconductor silicon wafer after polishing. In a conventional cleaning flow, after removing, from a wafer after polishing, a polishing agent with SC1 and ultrasonic waves, a pure water treatment and removal of particles and metal impurity by oxide film removal using hydrofluoric acid are performed, and after forming an oxide film by reoxidation by ozone water, a pure water treatment is performed, and then drying is performed, as shown in FIG. 2. DE 102 39 773 B3 discloses a method of cleaning a semiconductor silicon wafer after polishing. CN 104 157 766 A relates to an etching method for a chip of gallium arsenide substrate. JP H08 107100 A relates to a processing method for semiconductor wafer etching or washing. CITATION LIST PATENT LITERATURE Patent Document 1: Japanese Patent Application No. 2015-023069Patent Document 2: DE 102 39 773 B3Patent Document 3: CN 104 157 766 APatent Document 4: JP H08 107100 A SUMMARY OF INVENTION TECHNICAL PROBLEM However, SC1 is a chemical solution that is accompanied by anisotropic etching, and there have been problems that projecting defects are generated on a wafer surface and that surface roughness is degraded. In addition, a chemical like SC1 has a high environmental load and requires wastewater treatment, and requires a temperature adjustment mechanism, and therefore, there has been a problem that costs are extremely high. Meanwhile, it is disclosed that in a spin-cleaning method, a neutral aqueous solution of a polymer having a molecular weight of 10,000 or less is supplied to a substrate, the polymer is removed from the substrate, and cleaning is performed with a solution having ozone dissolved (Patent Document 1). However, there have been no suggestions of methods for solving the above problems in methods for cleaning in a batch. The present invention has been made to solve the above problems, and an object thereof is to provide a method for cleaning a semiconductor silicon wafer and an apparatus for cleaning the same by which the generation of projecting defects on the wafer surface and the degradation of surface roughness in a conventional method for cleaning a semiconductor silicon wafer can be suppressed, and wafer quality can be improved. In addition, it is also an object of the present invention to provide a method for cleaning a semiconductor silicon wafer and an apparatus for cleaning the same by which costs can be reduced compared to what is conventional. SOLUTION TO PROBLEM To solve the above problems, the present invention provides a method for cleaning a semiconductor silicon wafer for cleaning a semiconductor silicon wafer after polishing, the method comprising: an ozone water treatment step after polishing, of immersing, in ozone water, the semiconductor silicon wafer after polishing;a step of performing a first ultrasonic-wave-ozone-water treatment of cleaning the semiconductor silicon wafer at room temperature while immersing in ozone water and applying ultrasonic waves; anda step of performing a second ultrasonic-wave-ozone-water treatment of, after the step of performing the first ultrasonic-wave-ozone-water treatment, pulling out the semiconductor silicon wafer from the ozone water, performing a wafer rotation process of rotating, and cleaning the semiconductor silicon wafer after the wafer rotation process again at room temperature while immersing in ozone water and applying ultrasonic waves; whereinthe step of performing the second ultrasonic-wave-ozone-water treatment is performed once or more times, and subsequently, a hydrofluoric acid treatment step of immersing the semiconductor silicon wafer in hydrofluoric acid and an ozone water treatment step of immersing the semiconductor silicon wafer after the hydrofluoric acid treatment step in ozone water are performed. According to such a method for cleaning a semiconductor silicon wafer, a polishing agent adhered not only to the wafer surface but also to an edge portion can be removed efficiently by rotating the wafer, and wafer quality can be improved. In addition, since the cleaning is not accompanied by etching of the wafer, surface roughness and projecting defects can be improved. Furthermore, since treatment at room temperature is possible by using ozone water, costs can be reduced. Furthermore, in this case, when the step of performing the second ultrasonic-wave-ozon