Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-02-28
2002-07-09
Gupta, Yogendra N. (Department: 1746)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S176000, C510S504000, C510S245000, C134S002000, C134S003000, C134S013000, C134S042000, C438S906000, C430S905000
Reexamination Certificate
active
06417147
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a cleaning agent composition for use in removing contamination on the surface of a semiconductor wafer or a precisely worked instrument made of glass, ceramic or the like, which is used in the manufacture of a wafer. In addition, the present invention also relates to a method for cleaning a semiconductor wafer, a semiconductor wafer and a method for manufacturing a semiconductor wafer.
BACKGROUND OF THE INVENTION
Semiconductor devices such as transistor, diode, IC, LSI and rectifying element are manufactured by applying steps such as growth in vapor phase, formation of oxide film, diffusion of impurities and vapor deposition of electrode metal film, to a silicon wafer or a compound semiconductor wafer.
The electric properties of a semiconductor device are conspicuously affected by impurities, and therefore, the semiconductor wafer surface is thoroughly cleaned to remove contamination with impurities before applying the respective steps described above. As industrial means therefor, a large number of methods using a treating solution mainly comprising an organic alkali or a treating solution obtained by adding a complexing agent, a surfactant, a hydrogen peroxide and the like to an organic alkali have been proposed.
JP-A-50-147287 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) describes the fact that sole use of, for example, tetramethylammonium hydroxide (hereinafter referred to as “TMAH”) out of tetraalkylammonium hydroxides is effective in the degreasing, removal of contamination with inorganic substances and removal of ultra-thin oxide layer. However, (1) due to poor wettability to the surface to be treated, the cleaning power is not sufficiently high, and (2) etching activity depends on the orientation of silicon crystal (that is, the (
100
) plane is readily etched, whereas the (
111
) plane has resistance against the etching activity and in the case of a (
100
) mirror face wafer, this plane is roughened due to etching). Thus, improvement is still needed.
JP-A-50-158281 describes a solution obtained by adding a complexing agent to TMAH. In this case, the cleaning power may be improved as compared with the sole use of TMAH; however, the wettability to the surface to be treated is poor and the cleaning power is still insufficient.
With respect to the etching of silicone crystal, the addition of only a surfactant to an aqueous alkali solution may have an effect of preventing etching of silicone crystal. However, the effectiveness varies depending on the kind of surfactant, the alkali concentration, the temperature or the like. Therefore, a sufficiently high effect is not always ensured in all possible conditions. To cope with this, a case of using a hydrogen peroxide in addition to an alkali and a surfactant has been reported. For example, JP-A-63-274149 describes a case where etching can be satisfactorily controlled when a hydrogen peroxide is used in addition to a tetraalkylammonium hydroxide and a nonionic surfactant. This technique, however, has a problem in that the capability of removing particles is not sufficiently high.
As described in Japanese Patent 2,579,401, a case of adding an alkanolamine to a tetraalkylammonium hydroxide and a nonionic surfactant is known. By adding an alkanolamine, the cleaning power increases; however, this technique has a problem that the capability of removing particles is not sufficiently high.
With recent tends toward higher integration of semiconductors, the requirement for removing impurities is further increasing and a new cleaning solution having high effects of removing impurities, preventing re-adsorption of desorbed impurities and ensuring satisfactorily controlled etching property is being demanded.
SUMMARY OF THE INVENTION
The present invention has been made under these circumstances and an object of the present invention is to provide a cleaning agent composition having excellent cleaning power for contamination on the surface of a semiconductor wafer or various precisely worked instruments made of glass, ceramic or the like, which are used in the manufacture of semiconductor wafer. Another object of the present invention includes providing a method for cleaning a wafer, a method for manufacturing a semiconductor wafer, and a semiconductor wafer having a surface cleaned by a cleaning method.
As a result of extensive investigations to solve the above-described problems, the present inventors have found that these problems can be solved by using a cleaning agent composition comprising a specific fluorine-containing anionic surfactant, a quaternary ammonium hydroxide and/or an alkanolamine. The present invention has been accomplished based on this finding.
More specifically, an embodiment of the present invention is a cleaning agent composition comprising from 0.0001 to 5 mass % of a fluorine-containing anionic surfactant, from 0.001 to 30 mass % of a quaternary ammonium hydroxide and/or from 0.01 to 20 mass % of an alkanolamine. In a preferred embodiment of the present invention, the fluorine-containing anionic surfactant is at least one compound selected from the group consisting of carboxylic acids represented by the following formula (1):
R
1
COOM (1)
wherein R
1
represents a linear or branched alkyl group or alkenyl group having from 2 to 20 carbon atoms, with a part or all of hydrogen atoms being substituted by fluorine atom, and M represents a hydrogen atom, an alkali metal atom, an ammonium group, an alkylammonium group or an alkanolammonium group, salts thereof, sulfonic acids represented by the following formula (2):
R
2
SO
3
M (2)
wherein R
2
represents a linear or branched alkyl group or alkenyl group having from 2 to 20 carbon atoms, with a part or all of hydrogen atoms being substituted by fluorine atom, and M has the same meaning as defined above, and salts thereof, and in a more preferred embodiment, the fluorine-containing anionic surfactant is at least one compound selected from the group consisting of perfluorocaprylic acid, perfluorocapric acid, perfluorooctane sulfonic acid and salts thereof.
Also, in a preferred embodiment, the quaternary ammonium hydroxide is at least one compound selected from the group consisting of compounds represented by the following formula (3):
wherein R
3
, R
4
, R
5
and R
6
, which may be the same or different, each independently represents an alkyl group having from 1 to 6 carbon atoms or a hydroxyalkyl group, and in a more preferred embodiment, the quaternary ammonium hydroxide is tetramethylammonium hydroxide.
Also, in a preferred embodiment, the alkanolamine is at least one compound selected from the group consisting of compounds represented by the following formula (4):
wherein R
7
represents a hydroxyalkyl group having from 1 to 4 carbon atoms, R
8
and R
9
, which may be the same or different, each independently represents a hydrogen atom, an alkyl group having from 1 to 4 carbon atoms, a hydroxyalkyl group having from 1 to 4 carbon atoms or an aminoalkyl group having from 1 to 4 carbon atoms, and R
8
and R
9
may combine to represent an alkylene group having from 3 to 6 carbon atoms, which may be interrupted by an oxygen atom or a nitrogen atom, and in a more preferred embodiment, the alkanolamine is at least one compound selected from the group consisting of monoethanolamine, diethanolamine and triethanolamine.
In a preferred embodiment of the present invention, the composition contains from 0.0001 to 5 mass % of a nonionic surfactant, and in a more preferred embodiment, the nonionic surfactant is at least one compound selected from the group consisting of polyoxyalkylene alkyl ether compounds represented by the following formula (5):
R
10
—O—(R
11
—O)
p
—H (5)
wherein R
10
represents an alkyl group having from 6 to 20 carbon atoms, R
11
represents an alkylene group having from 2 to 4 carbon atoms, and p represents an integer of 3 to 20, polyoxyalkylene aryl ether compounds represented by the following formula (6):
R
12
—C
6
Amemiya Masahiro
Matsuki Kunio
Saito Satoshi
Yano Katsuji
Gupta Yogendra N.
Showa Denko K.K.
Webb Gregory E.
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