Photography – Fluid-treating apparatus – Having testing – calibration – or indicating
Reexamination Certificate
2001-03-13
2002-10-01
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Having testing, calibration, or indicating
C396S604000, C396S611000, C396S622000
Reexamination Certificate
active
06457882
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate processing method and a substrate processing apparatus for forming a desired resist pattern on a front face of a substrate such as a semiconductor wafer and an LCD substrate.
2. Description of the Related Art
For example, in a photolithography process in semiconductor device fabrication, a resist film is formed on a front surface of a semiconductor wafer (hereinafter called “a wafer”) and after exposure processing is performed, developing processing is performed, whereby a predetermined resist pattern is formed.
Such a photolithography process is performed by transferring a wafer to and from a resist coating unit for forming a resist film on the wafer, an exposure processing unit for performing exposure processing for the wafer, and a developing processing unit for performing developing processing for the wafer after the exposure processing.
By the way, in recent years, a demand for miniscule resist patterns formed on the front faces of wafers has been increased, and hence it is required to control the line width of a resist pattern more tightly. Conventionally, the line width of a resist pattern is controlled in such a manner as, for example, an operator actually measures the line width of a resist pattern on the front face of a wafer transferred from the resist coating and developing system by using an SEM, then determines whether or not the line width is included in the range of the specifications, and feeds the determination results back to the processing condition of each processing unit.
However, the aforementioned method has the disadvantages of requiring an expensive SEM, and much time and effort for measuring a line width. Further, on measuring a line width by using the SEM, the wafer has to be temporally carried out and transferred into the vacuum sample chamber, thus causing the disadvantage of the wafer being contaminated.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a substrate processing method and a substrate processing apparatus capable of controlling the line width of a resist pattern with high precision.
According to a first aspect of the present invention, a substrate processing method for forming a resist film on a substrate with a base film being formed, and performing an exposure processing and a developing processing for the resist film to thereby form a desired resist pattern, comprises a base reflected light analyzing step of radiating a light of the same wavelength as an exposure light radiated during the exposure processing to the base film and analyzing a reflected light, before forming the resist film, and a processing condition control step of controlling at least one of a resist film forming condition, a condition for a heating processing performed after the resist film is formed, an exposure processing condition and a developing processing condition, based on an analysis of the reflected light.
The present invention is made in view of the fact that the exposure light is reflected on the base film on exposure, a nd this exerts an influence on the exposure, whereby the line width of the resist pattern is varied.
For example, SiO
2
and A
1
with different light reflectivity are formed as the base film on a semiconductor wafer as a substrate, the ratio of the area with SiO
2
and the area with A
1
differs according to the circuit pattern to be formed, and the reflectivity state of a light on the base film differs according to the ratio. Consequently, if the resist pattern is formed under the same condition, the line width of the resist pattern differs according to the reflectivity of the light on the base film.
Thus, in the present invention, by measuring the reflectively of the base film with a light of the same wavelength as the exposure light, an influence that the base film exerts on the exposure amount during the exposure is accurately found, thereby controlling the resist coating condition and the exposure condition.
It should be noted that even with use of the light of the same wavelength as the exposure light, the radiation is performed before the resist film is formed, thus causing no adverse effects on the resist pattern.
According to a second aspect of the present invention, a substrate processing method for forming a resist film on a substrate with a base film being formed, and performing an exposure processing and a developing processing for the resist film to thereby form a desired resist pattern, comprises a base reflected light analyzing step of radiating a light of multiple wavelengths to the base film and analyzing a component of the same wavelength as an exposure light radiated during the exposure processing out of the reflected lights before forming the resist film, and a condition control step of controlling at least one of a resist film forming condition, a condition for heating processing performed after the resist film is formed, an exposure processing condition and a developing processing condition, based on the analysis of the reflected light.
According to the above configuration, by using the light of multiple wavelengths, even when the wavelength of the exposure light varies, the component of the same wavelength as the exposure light is analyzed out of the reflected lights, thus making it possible to find an influence that the state of the base film exerts on the line width of the resist pattern.
According to a third aspect of the present invention, a substrate processing method for forming a resist film on a substrate with at least a base film being formed and transferring the substrate to an aligner, comprises a base reflected light analyzing step of radiating a light of the same wavelength as an exposure light in the aligner and analyzing a reflected light before forming the resist film, a step for obtaining an optimal exposure processing condition in the aligner based on an analysis of the reflected light, and a step of outputting the obtained optimal exposure processing condition to the aligner side. Thereby, the line width of the resist pattern can be controlled with high precision.
According to a fourth aspect of the present invention, a substrate processing method for forming a resist film on a substrate with a base film being formed, and performing an exposure processing and a developing processing for the resist film to thereby form a desired resist pattern, comprises a step of radiating a light of the same wavelength as an exposure light radiated during the exposure processing to the base film and controlling at least one of a resist film forming condition and an exposure processing condition based thereon, and a step of measuring a resist film thickness with use of a light of a different wavelength from the exposure light radiated during the exposure processing, after forming the resist film.
According to the above configuration, the light of the same wavelength as the exposure light is used before the resist film is formed, but after the resist film is formed, the light of a different wavelength from the exposure light is used, and thus various kinds of measurements can be performed without having adverse effects on the resist pattern.
According to a fifth aspect of the present invention, a substrate processing method for supplying a coating solution to a substrate and rotating the substrate to thereby spread the coating solution by a centrifugal force of the rotation, then further rotating the substrate to thereby spin-dry the coating solution, comprising:
a correlation calculating step of forming coating films at a plurality of spin rotational frequencies in a predetermined range based on a set target film thickness, and based thereon, obtaining a correlation between the spin rotational frequency and the film thickness, a judging step of judging whether the target film thickness is included in a range of the coating film obtained in the above step, a spin rotational frequency calculating step of applying the target film thickness to the correlation when it is judged that the tar
Nakajima Yoshiyuki
Ogata Kunie
Tateyama Masanori
Uemura Ryouichi
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Rutledge D.
Tokyo Electron Limited
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