Agitating – Having specified feed means – Responsive to condition sensor
Reexamination Certificate
2002-02-06
2003-07-08
Soohoo, Tony G. (Department: 1723)
Agitating
Having specified feed means
Responsive to condition sensor
C366S152400, C366S153100, C366S160100
Reexamination Certificate
active
06588927
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to developer producing equipment and a developer producing method, and more particularly to equipment which is connected via piping to working equipment in which electronic circuits on which fine working is performed are formed, and which manufactures an alkali type developer that is used to develop photoresists or the like in the abovementioned working equipment, and a method for manufacturing this alkali type developer.
2. Description of the Related Art
Generally, resist materials used in photolithographic processes in the manufacture of devices such as electronic devices or the like that have electronic circuits on which fine working is performed include positive type materials that are solubilized by exposure to light, and negative type materials that are insolubilized by exposure to light. As one example, in the manufacture of semiconductor devices, flat panel display (FPD) substrates and the like, such photo-etching is repeatedly performed; accordingly, mainly positive type resists are commonly used.
Aqueous solutions of inorganic alkalies consisting of sodium phosphate, caustic soda, sodium silicate or mixtures of these substances with other inorganic alkalies or the like may be cited as examples of developer materials for positive type resists. Furthermore, in cases where contamination by alkali metals is a concern, aqueous solutions of amine type organic alkalies that contain no metals, aqueous solutions of tetramethylammonium hydroxide (TMAH), aqueous solutions of trimethylmonoethanolammonium hydroxide (choline) or the like are used. Among the latter materials, an aqueous solution of TMAH with a concentration of 2.38% are widely used.
Furthermore, developers prepared from these materials are used in large quantities in developing devices using a spray system, spin-coating system, dipping system or the like.
In developers used on photo-resists, the composition and concentration of the developer must be strictly controlled in order to obtain the maximum resolution, patterning sharpness (sharpness), stability and high yield in accordance with the developing process.
In particular, as the density of patterning has increased in recent years, there has been a demand for finer patterning widths. For example, in the case of semiconductor substrates, a demand has appeared for line widths on the 0.1 &mgr;m level; furthermore, in the case of flat panel display substrates, there is now a demand for line widths on the 1 &mgr;m level, and in the case of multi-layer printed circuit boards, there is a demand for line widths on the 10 &mgr;m level. Furthermore, there is now a demand for line widths of 1 &mgr;m or less in order to incorporate semiconductor circuits into flat panel display substrates using low-temperature polycrystalline silicon TFT techniques.
Consequently, there is a strong demand for improved precision of developer concentrations in order to reduce the variation in the effective sensitivity of photo-resists. For example, a range of values that deviate from the specified concentration by ±{fraction (1/1000)} or less is required as the control range of the developer concentration. Especially in the case of an aqueous solution of TMAH, a range of values that deviate from the specified concentration by ±{fraction (1/2000)} or less (more concretely, 2.380±0.001 wt %) is required.
Furthermore, in order to eliminate patterning defects, it is required that various developers contain extremely few particles, i.e., the content of particles with a size of 0.1 &mgr;m or greater must be 10 or fewer particles per milliliter of developer.
In recent years, moreover, there has been a further increase in the amount of developer used as a result of increased size and increased mass production of substrates.
Thus, along with a sharp demand for improved precision in developer concentrations and demand for particle-free developers, there has been a strong demand for measures to facilitate mass production and reduce cost.
In the case of conventional techniques, however, adjustment of the composition and concentration of developers in manufacturing plants for semiconductor devices and the like has been extremely difficult, not only in terms of equipment and operating costs, but also from the standpoint of sufficient control the of the composition and concentration of the developers.
For these reasons, it has been unavoidable necessary in manufacturing plants for semiconductor devices and the like (hereafter referred to as the “use side”) to use developers whose composition and concentration have been adjusted exclusively by the developer makers (hereafter referred to as the “supply side”).
In such cases, a method is used in which a developer stock solution that has been prepared with a specified composition is diluted with pure water on the supply side, the developer thus adjusted to a specified concentration is places in containers, and this adjusted developer is supplied to the use side.
In this case, the dilution factor of the developer stock solution varies according to the solution composition and stock solution concentration, the type of positive resist or the like that is the object of development, and the intended use. Ordinarily, the stock solution is diluted approximately 8 to 40 times. Accordingly, the amount of developer prepared on the supply side is greatly increased in accordance with the dilution factor, thus resulting in an increase in the work involved in preparing containers and filling containers for the shipping of the developer to the use side, and an increase in shipping costs. As a result, such expenses account for a considerable portion of the cost of the developer.
Furthermore, considerable time is required for shipping and storage until the developer prepared on the supply side can be used on the use side, and the developer deteriorates during this period.
Moreover, since developers tend to absorb carbon dioxide gas from the air, variations in concentration caused by the absorption of carbon dioxide gas occur during the dilution operation and during the storage of the diluted developer, even if a dilution apparatus is installed on the use side. This may also be cited as one of the reasons why the dilution of developers has not been performed on the use side in semiconductor device manufacturing plants or the like.
In order to solve these problems, a developer dilution apparatus comprising an agitating tank into which a photo-resist alkali type developer stock solution and pure water are introduced and subjected to forced agitation for a specified period of time, conductivity measuring means for extracting a portion of the mixed solution in the agitating tank, measuring the conductivity of this solution and then returning the solution of the agitating tank, control means for controlling either the photo-resist alkali type developer stock solution or pure water that is supplied to the agitating tank on the basis of the output signal from the conductivity measuring means, a storage tank into which the mixed solution from the agitating tank is introduced, and in which this mixed solution is stored, and nitrogen gas sealing means for sealing the agitating tank and storage tank with nitrogen gas, is disclosed in Japanese Patent No. 2751849. Furthermore, this apparatus makes it possible to prepare the developer on the use side by mixing the developer stock solution and pure water.
SUMMARY OF THE INVENTION
However, when the present inventors investigated the abovementioned conventional apparatus in detail in the light of requirements arising in the manufacture of electronic circuit boards for semiconductor devices and the like, which have become progressively finer and thinner, it became clear that the precision of the alkali concentration and the particle concentration in the developer obtained are not always satisfactory, and that there is a strong demand for improved quality in terms of high precision and particle-free solutions.
Accordingly, the present invention
Hozan Takahiro
Kikukawa Makoto
Morita Satoru
Nakagawa Toshimoto
Ogawa Shu
Nagase & Co. Ltd.
Rosenthal & Osha L.L.P.
Soohoo Tony G.
LandOfFree
Purified developer producing equipment and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Purified developer producing equipment and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Purified developer producing equipment and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3037781