Cleaning and liquid contact with solids – Apparatus – Sequential work treating receptacles or stations with means...
Reexamination Certificate
1998-01-22
2001-09-04
Stinson, Frankie L. (Department: 1743)
Cleaning and liquid contact with solids
Apparatus
Sequential work treating receptacles or stations with means...
C134S105000, C134S095300, C134S901000
Reexamination Certificate
active
06283134
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application serial no. 86119669, filed Dec. 24, 1997, the full disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an apparatus for removing photo-resist, and more particularly to a gradient elution method of removing photo-resist without moving to another region other than the current processing region.
2. Description of the Related Art
The process of fabricating an IC is very complex. Hundreds of steps are needed for making an IC. The fabrication normally takes one or two month to complete. The IC industry is a high technology industry including four main branches: IC design, wafer fabrication, wafer testing, and wafer packaging.
For example, the main purpose for the process of development is to clean the exposed part of photo-resist layer by chemical reaction, and to develop the transferred pattern.
There are many methods to perform a development process. For a commercial in-line operation, a “spray/puddle” method is normally adapted. The “spray/puddle” method comprises three steps. Firstly, a developer is sprayed onto a wafer deposed on a spinner. Secondly, the wafer is puddle developed in a stationary status. Thirdly, after cleaning by water, the wafer is spun dry.
The next step after development is, before performing photolithography, to perform a quality control step, that is, an “after inspection (ADI)” step. The ADI step is to ensure the accuracy after the subsequent photolithography process. Thus, any abnormal state or condition can be found and reworked before the whole wafer to be damaged in the subsequent process.
During photolithography, such as forming photo-resist, exposure, bake, or development, or before cured by ultra-violet and performing plasma bombardment, if a fault is found, photo-resist has to be removed and reworked to avoid a further damage. In the conventional semiconductor process, the region of removing photo-resist and the processing region of photolithography is separate. Therefore, if a fault is found during fabrication, the photo-resist has to be removed in region of removing photo-resist. The removal of photo-resist can not be performed in the processing region of photolithography, and thus, consumes a long fabricating time.
One of the conventional method to remove photo-resist is to use an organic solution. The bonding of the photo-resist is destroyed by and dissolved in the organic solution. Normally, groups of acetone and aromatic base are used as the organic solution for removing photo-resist. In addition, photo-resist is an organic compound composed of carbon and hydrogen element. Therefore, inorganic solution such as sulfuric acid (H
2
SO
4
) and perhydrol (H
2
O
2
), can be used to oxidise the carbon element into carbon dioxide (CO
2
) by perhydrol and to remove the hydrogen element by dehydration of sulfuric acid. Another method to remove photo-resist is by plasma.
Though several methods are available to remove photo-resist in a conventional process, almost all the removal regions of photo-resist are separated from the processing region of photo-lithography. Therefore, during the process, the faulty wafers have to be moved from the current processing region to the removal region of photo-resist for rework.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an apparatus for removing photo-resist. The photo-resist is removed in the current processing region without being moved to another region.
It is therefore another object of the invention to provide an apparatus for removing photo-resist. Using acetone as medium, so that N-methyl-pyrrolidone (NMP) and deionized water are mutually dissolvable, and photo-resist on the wafer is removed by a gradient elution method.
To achieve these objects and advantages, and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention is directed towards an apparatus for removing photo-resist. The apparatus comprises carriers for carrying a wafer, hot plates to remove residue solvent on the wafer, a cooling plate to decrease the wafer temperature, an reverse unit to turn over the wafer, a development unit to develop and remove photo-resist on the wafer, a top scrubbing unit to clean a top side of the wafer, and a back scrubbing unit to clean a back side of the wafer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
REFERENCES:
patent: 4715392 (1987-12-01), Abe et al.
patent: 4745422 (1988-05-01), Matsukoa et al.
patent: 4850381 (1989-07-01), Moe et al.
patent: 5177514 (1993-01-01), Ushijima et al.
patent: 5361449 (1994-11-01), Akimoto
patent: 5374312 (1994-12-01), Hasebe et al.
patent: 5518542 (1996-05-01), Matsukawa et al.
patent: 5853961 (1998-12-01), Sakai et al.
patent: 5858112 (1999-01-01), Yonemizu et al.
Chung Army
Hong Hsi-Hsin
Ku Chi-Fa
Rabin & Champagne PC
Stinson Frankie L.
United Microelectronics Corp.
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