Compositions – Compositions containing a single chemical reactant or plural... – Organic reactant
Patent
1992-09-24
1994-04-12
Albrecht, Dennis
Compositions
Compositions containing a single chemical reactant or plural...
Organic reactant
252103, 25218629, 252541, 252545, 252DIG11, 423272, 423584, C11D 706, C11D 718, C11D 732, C11D 736
Patent
active
053023110
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a cleaning solution for a semiconductor substrate. More specifically, it relates to a cleaning solution of a semiconductor which comprises a basic aqueous solution of hydrogen peroxide containing a chelating agent having at least two phosphonic acid groups.
BACKGROUND ART
In producing semiconductor elements, cleaning has been carried out with chemicals to remove contaminants adhered on a surface of a semiconductor substrate including silicon wafer. As the chemicals, cleaning solutions containing mainly hydrogen peroxide are often used. For example, a mixed aqueous solution of hydrochloric acid and hydrogen peroxide, a mixed aqueous solution of sulfuric acid and hydrogen peroxide, a mixed aqueous solution of ammonia and hydrogen peroxide and the like are known.
Particularly, a mixed aqueous solution of ammonia indicating basicity in an aqueous solution and hydrogen peroxide is most widely used since it is effective in removing fine particles adhered on a substrate surface. However, in a basic cleaning solution, there has been a problem that metal impurities including Fe and Cu come to be insoluble and adhere on a substrate to exert a bad influence on a characteristics of a semiconductor element.
In order to solve the problem, high purification of ammonia and hydrogen peroxide themselves has been promoting. Presently, a concentration of metal impurities in ammonia and hydrogen peroxide leads to 1 ppb or below. However, on the contrary, there has been a problem that a high purified cleaning solution comes to be sensitive to metal contamination from the outside and metal contamination from a cleaning vessel etc., causes instability for characteristics of a semiconductor element.
On the other hand, as the other methods for preventing adhesion of metal impurities to a semiconductor substrate, addition of a chelating agent has been suggested. For example, in German Patent Published No. 3822350, a method of using ethylenediaminetetraacetic acid (EDTA) as a chelating agent has been suggested. However, in fact, advantageous effects due to addition of EDTA are scarcely observed. Accordingly, a method for treatment of rendering stable advantageous effects has been desired.
DISCLOSURE OF THE INVENTION
The object of the present invention is to solve the foregoing problems and provide a cleaning solution which, even if a basic cleaning solution of hydrogen peroxide is contaminated with metal impurities, makes it possible to prevent contaminants adhering to a substrate surface and carry out stabilized cleaning of the substrate.
The present inventors have made extensive study to attain the foregoing object. As a result, it has been found that it is effective to add a chelating agent having at least two phosphonic acid groups. The present invention has been accomplished on the basis of above finding.
Thus, the present invention relates to a cleaning solution of a semiconductor substrate which comprises a basic aqueous solution of hydrogen peroxide containing a chelating agent having at least two phosphonic acid groups.
The chelating agent using in the present invention is not limited except that it is a chelating agent having at least two phosphonic acid groups. The typical examples include aminotri( methylenephosphonic acid). 1-hydroxyethylidene-1, 1-diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), hexamethlenediaminetetra(methylenephosphonic acid), propylenediaminetetra(methylenephoshonic acid), diethylenetriaminepenta(methylenephosphonic acid), triethylenetetraminehexa(methylenephosphonic acid), triaminotriethylaminehexa(methylenephoshonic acid), trans-1,2-cyclohexanediaminetetra(methylenephosphonic acid), glycoletherdiaminetetra(methylenephosphonic acid), and tetraethylenepentaminehepta(methylenephosphonic acid) etc.
Among them, ethylenediaminetetra (methylenephosphonic acid), propylenediaminetetra(methylenephosphonic acid) and the like having a strong chelating force, are particularly preferable. The chelating agent using in the present invention
REFERENCES:
patent: 3122417 (1964-02-01), Blaser
patent: 3234140 (1966-02-01), Irani
patent: 3701825 (1972-10-01), Radimer
patent: 4304762 (1981-12-01), Leigh
patent: 4497725 (1985-02-01), Smith
patent: 4614646 (1986-09-01), Christiansen
patent: 4808259 (1989-02-01), Jillie
patent: 4885106 (1989-12-01), Lapham et al.
patent: 5104635 (1992-04-01), Kanada
RCA Review, vol. 31, No. 2, Jun. 1970, Princeton, N.J., pp. 187-206.
Kawakami Michiya
Sugihara Yasuo
Tanaka Kazushige
Albrecht Dennis
Mitsubishi Gas Chemical Company Inc.
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