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CN-121975441-A - Preparation method of alumina polishing solution applied to gallium arsenide

CN121975441ACN 121975441 ACN121975441 ACN 121975441ACN-121975441-A

Abstract

The invention provides a preparation method of alumina polishing solution applied to gallium arsenide, which relates to the field of polishing materials and comprises the steps of forming a protective layer on the surface of an alumina raw material through a protective agent, adding strong acid for ball milling, performing centrifugal separation after ball milling, washing to neutrality to obtain neutral precipitate, drying the neutral precipitate, filtering, further removing gamma-phase alumina in the alumina raw material to obtain pretreated alpha-phase alumina, adding a copolymer dispersing agent to ensure that the dispersion stability of the alpha-phase alumina is higher, and then adding a chelating agent and an oxidizing agent to form a finished product of the polishing solution. The preparation method provided by the invention not only improves the purity of alpha-phase alumina, but also further ensures the dispersibility of the abrasive by combining the steric hindrance effect of the copolymer dispersing agent, and the two are synergistic together, thereby improving the polishing rate and the polishing quality.

Inventors

  • LIU LEI
  • MU YUANYING
  • WANG PEIDONG

Assignees

  • 兴华清科(天津)电子材料有限公司

Dates

Publication Date
20260505
Application Date
20260331

Claims (9)

  1. 1. The preparation method of the alumina polishing solution applied to gallium arsenide is characterized by comprising the following steps of: The preparation method comprises the steps of pre-treating alumina particles, namely stirring and dispersing the alumina particles into deionized water to obtain an abrasive dispersion system, adding 0.3% -3% of protective agent into the abrasive dispersion system according to mass fraction, stirring to obtain an abrasive system with a protective layer, adding 2% -10% of strong acid into the abrasive system with the protective layer, stirring, ball-milling for 1-3 hours, performing centrifugal separation after ball milling, washing to neutrality to obtain neutral precipitate, drying the neutral precipitate, and filtering to obtain pretreated alpha-phase alumina, wherein the protective agent comprises one or more of nitric acid, hydrochloric acid or sulfuric acid; Dispersing the pretreated alpha-phase alumina into deionized water, adding an acidic pH regulator to regulate the pH value to 2.5-4.5 to obtain an alpha-phase alumina dispersion system, and then adding 0.5-5% of PAA-b-PEG-b-PPA terpolymer and/or acrylic acid-acrylic ester-phosphonic acid-sulfonic acid tetrapolymer according to mass fraction to stir, and adding an alkaline pH regulator to regulate the pH value to 9-10 during stirring to obtain a dispersion modified abrasive system; Adding a chelating agent, namely adding 0.3% -2.5% of EDTA chelating agent into the dispersion modified abrasive material system according to mass fraction to obtain an abrasive material complex system; And (3) adding an oxidant, namely adding 1% -2% of the oxidant into the abrasive complex system according to mass fraction to obtain a finished polishing solution.
  2. 2. The method for preparing alumina polishing solution for gallium arsenide according to claim 1, wherein in the step of pretreating alumina particles, alumina particles and deionized water are placed in a high-speed disperser and stirred and dispersed for 30min at a rotation speed of 2500r/min to obtain the abrasive dispersion system, the protective agent is added and stirred at a rotation speed of 500r/min, and the strong acid is added and kept at a rotation speed of 500 r/min.
  3. 3. The method for preparing an alumina polishing solution for gallium arsenide according to claim 2, further comprising: Adding strong acid, stirring, transferring the solution into a planetary ball mill, ball milling for 1-3 h at a rotating speed of 1500r/min, after ball milling, adopting a high-speed centrifuge to centrifugally separate for 10min at a rotating speed of 8000r/min, collecting precipitate, and repeatedly washing the precipitate with deionized water until the pH value of washing solution is=7, thus obtaining neutral precipitate.
  4. 4. The method for preparing an alumina polishing solution for gallium arsenide according to claim 3, further comprising: and (3) placing the neutral precipitate in a blast drying oven at 80 ℃ for drying for 4 hours, and filtering by adopting a 0.1 mu m microfiltration membrane after drying to obtain the pretreated alpha-phase alumina.
  5. 5. The method for preparing alumina polishing solution for gallium arsenide according to claim 1, wherein in the step of adding copolymer dispersant, the pretreated alpha-phase alumina and deionized water are placed in a high-speed disperser, stirred and dispersed for 30min at a rotation speed of 1000r/min, and after the PAA-b-PEG-b-PPA terpolymer and/or the acrylic acid-acrylic ester-phosphonic acid-sulfonic acid tetrapolymer are added, the mixture is stirred for 1h at a rotation speed of 500r/min, and then potassium hydroxide is added to adjust the pH value to 9-10.
  6. 6. The method for preparing alumina polishing solution for gallium arsenide according to any one of claims 1 to 5, wherein the protecting agent is hydroxy phosphonic acid in an amount of 2% of the mass of the abrasive dispersion, and the strong acid is nitric acid in an amount of 9% of the mass of the abrasive dispersion.
  7. 7. The method for preparing an alumina polishing solution for gallium arsenide according to any one of claims 1 to 5, wherein the amount of the PAA-b-PEG-b-PPA terpolymer and/or the acrylic-acrylic ester-phosphonic acid-sulfonic acid tetrapolymer is 3% of the mass of the alpha-phase alumina dispersion.
  8. 8. The method of claim 1, wherein the EDTA chelating agent is used in an amount of 1.5% of the mass of the dispersion modified abrasive system.
  9. 9. The method for preparing an alumina polishing solution for gallium arsenide according to claim 1, wherein the oxidizing agent is sodium hypochlorite, and the mass of the oxidizing agent is 1.5% of the mass of the abrasive complex system.

Description

Preparation method of alumina polishing solution applied to gallium arsenide Technical Field The invention relates to the field of polishing materials, in particular to a preparation method of aluminum oxide polishing solution applied to gallium arsenide. Background Gallium arsenide (GaAs) is widely used in the fields of high frequency communication devices, optoelectronic devices (such as LEDs, lasers, solar cells), and integrated circuit substrates, because of its excellent physicochemical properties such as high electron mobility, wide forbidden band, and direct band gap. With the continuous iteration of device technology, the surface quality requirement on the gallium arsenide substrate is higher and higher, and Chemical Mechanical Polishing (CMP) is the mainstream technology for realizing the global planarization of the wafer at present. During the CMP process of gallium arsenide, the composition of the polishing liquid plays a decisive role in the polishing rate (MRR) and surface quality (roughness, scratches). In practicing the present invention, applicants have found that increasing the gallium arsenide polishing liquid rate is currently performed with a-phase alumina (alphaAl 2O3) as an abrasive, however, the finally obtained alpha is due to improper control of the calcination process, differences in the purity of the raw materials, etcA certain amount of gamma will often remain in the Al 2O3 productAl2O3,γAl 2O3 is a thermodynamically metastable crystal form, is unstable, can influence the polishing rate in the gallium arsenide polishing process, and can produce the problems of scratch and the like, and secondly, the alpha-phase alumina is used for removing impurities gammaWhen Al 2O3 is used, the surface hydroxyl is damaged, active groups of aluminum oxide are damaged, and the aluminum oxide is not easy to disperse, so that the problems of high gallium arsenide surface roughness, scratch and the like are caused. Therefore, how to develop a polishing solution capable of improving scratch and roughness while considering high gallium arsenide polishing rate is a technical problem to be solved by those skilled in the art. Disclosure of Invention The invention aims to at least solve one of the technical problems in the prior art or related art, and provides a preparation method of alumina polishing solution applied to gallium arsenide, the prepared polishing solution is used for polishing operation, can give consideration to high gallium arsenide polishing rate, can improve scratch and roughness, and has stable dispersion of abrasive materials and good matching with gallium arsenide surface potential. The first aspect of the invention discloses a preparation method of alumina polishing solution applied to gallium arsenide, comprising the steps of pretreating alumina particles, namely stirring and dispersing the alumina particles into deionized water to obtain an abrasive dispersion system; adding 0.3-3% of a protective agent into an abrasive dispersion system according to mass fraction, stirring to obtain an abrasive system with a protective layer, adding 2-10% of strong acid into the abrasive system with the protective layer, stirring, ball milling for 1-3 hours, performing centrifugal separation after ball milling, washing to neutrality to obtain neutral precipitate, drying the neutral precipitate, filtering to obtain pretreated alpha-phase alumina, wherein the protective agent comprises one or more of hydroxy phosphonic acid and/or hydroxy ethylene diphosphonic acid, the strong acid comprises nitric acid, hydrochloric acid or sulfuric acid, adding copolymer dispersing agent, dispersing the pretreated alpha-phase alumina into deionized water, adding an acidic pH regulator, regulating the pH value to 2.5-4.5, obtaining an alpha-phase alumina dispersion system, adding 0.5-5% of PAA-b-PEG-b-PPA-phosphonic acid-sulfonic acid quaternary copolymer, stirring, adding an alkaline pH regulator into the abrasive dispersion system according to mass fraction, regulating the pH value to 9-10% of the abrasive system, and adding the complexing agent into the abrasive system according to mass fraction of the abrasive system, and adding the complexing agent to obtain the abrasive system according to mass fraction of 2-2%. According to the preparation method of the alumina polishing solution applied to gallium arsenide, in the step of pretreatment of alumina particles, preferably, the alumina particles and deionized water are placed in a high-speed dispersing machine and are stirred and dispersed for 30min at the rotating speed of 2500r/min to obtain an abrasive dispersion system, the abrasive dispersion system is stirred at the rotating speed of 500r/min when a protective agent is added, and the rotating speed of 500r/min is kept when strong acid is added. According to the preparation method of the alumina polishing solution applied to gallium arsenide, preferably, in the step of alumina particle pretreatment, strong