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(12) United States Patent ao) Patent No.: us 6,283,134 Bi
Chung et al. (45) Date of Patent: Sep. 4,2001
(54) APPARATUS FOR REMOVING PHOTORESIST
(75) Inventors: Army Chung, Hsinchu; Hsi-Hsin Hong, Nantou Hsien; Chi-Fa Ku, Kaohsiung Hsien, all of (TW)
(73) Assignee: United Microelectronics Corp., Taiwan (CN)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/010,683
(22) Filed: Jan. 22, 1998
(30) Foreign Application Priority Data
Dec. 24, 1997 (TW) 86119669
(51) Int. C I. B08B 3/02
(52) U.S. CI 134/62; 134/105; 134/95.3;
(58) Field of Search 134/61, 62, 105,
134/111, 902, 95.2, 95.3
* cited by examiner
Primary Examiner—Frankie L. Stinson
(74) Attorney, Agent, or Firm—Rabin & Champagne, PC
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.
19 Claims, 2 Drawing Sheets
APPARATUS FOR REMOVING PHOTO-
CROSS-REFERENCE TO RELATED
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 10
1. Field of the Invention
The invention relates to an apparatus for removing photoresist, 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 20 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 25 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 3J 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 ultraviolet and performing plasma bombardment, if a fault is found, photo-resist has to be removed and reworked to avoid 45 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 50 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 55 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 go sulfuric acid (H2S04) and perhydrol (H202), can be used to oxidise the carbon element into carbon dioxide (C02) by perhydrol and to remove the hydrogen element by dehydration of sulfuric acid. Another method to remove photo-resist is by plasma. 65
Though several methods are available to remove photoresist 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-mefhyl-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.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a configuration of an apparatus for removing photo-resist in a preferred embodiment according to the invention;
FIG. 2 is a flow chart of for removing photo-resist using the apparatus shown on FIG. 1;
FIG. 3 shows the configuration of the development unit in the apparatus shown on FIG. 1;
FIG. 4 shows the internal structure of a spray in the apparatus shown on FIG. 1; and
FIG. 5 shows the configuration of a recycling unit.
DESCRIPTION OF THE PREFERRED
Referring to FIG. 1, an apparatus for removing photoresist in a preferred embodiment according to the invention is shown. The apparatus for removing photoresist comprises four carrier stations 10 for wafer carrying, a development unit 20 to develop or remove photo-resist on the wafer, a top scrubbing unit 30 to clean the top side of the wafer, a reverse unit 50 to turn over the wafer for cleaning the opposite side, a back scrubbing unit 40 to clean the back side of the wafer, two hot plate to remove the residue solvent on the wafer, and a cooling plate to cool down the temperature of the wafer.
Referring FIG. 1 and FIG. 2, an apparatus, and by which the operation flow of removing photo-resist are shown. A wafer is deposed on one of the carriers 10. The wafer is then delivered to the development unit 20. After development and removal of photo-resist, the wafer is delivered to the top scrubbing unit 30 for top side scrubbing and cleaning. Through the reverse unit 50, the wafer is turned over for the preparation of back side scrubbing and cleaning. The wafer is delivered to the back scrubbing unit 40 for back side