JPH04352417A - Photoresist coater for semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the partial dispersion of a resist film thickness in a wafer surface by obviating the falling of a solid body formed at the front end of a resist nozzle. CONSTITUTION:A washing tank 5, a washing nozzle 2, a drain tank 3 and a washing-tank driving section 6 are installed around a cup 1 conducting coating treatment. A solvent is ejected from the washing nozzle 2, and the surface of the front end of a resist nozzle 4 is washed. When treatment reaches a set time, the blow-off of the solvent is stopped. The front end of the resist nozzle 4 is dipped in the washing tank 5, into which the solvent is admitted, and the washing tank 5 is moved vertically by the washing-tank driving section 6 and the inner surface of the resist nozzle 4 is washed. The operation is repeated for the set time. A resist is discharged to the drain tank 3 from the resist nozzle 4 only by set number in order to expel an excess solvent component in the resist nozzle 4.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to photoresist (hereinafter referred to as
The present invention relates to a photoresist coating apparatus (hereinafter simply referred to as a resist coating apparatus) for semiconductor devices that coats a semiconductor wafer (hereinafter simply referred to as a wafer) with a photoresist coating apparatus (hereinafter simply referred to as a resist coating apparatus).

0002

2. Description of the Related Art The operation of a conventional resist coating apparatus of this type will be explained in order, as shown in the cross-sectional view of FIG. First, as shown in FIG. 5, a certain amount of resist is dropped from the resist nozzle 4 onto the wafer 8 adsorbed by the chuck 7. After that, the wafer 8 is rotated by the spin motor 9.
The resist film thickness on the wafer 8 is made uniform by rotating the wafer 8 to scatter unnecessary resist. The above operation is repeated for each wafer, but if the wafer 8 is not processed continuously and the resist is not dropped for a certain period of time, the resist at the tip of the resist nozzle 4 will be in contact with air for a long time. Become. As a result, a portion of the resist dries, and solid matter is generated on the inner wall of the resist nozzle 4.

[0003] When the process is restarted next time in this state, the resist mixed with the solid matter is dropped, resulting in defects in which the resist film thickness differs locally within the wafer surface. To prevent such defects from occurring, the resist nozzle 4 is moved onto the drain hose 10 (indicated by a dotted line), and the resist is discharged from the resist nozzle 4 onto the drain hose 10 several dozen times to discharge solid matter. The inner wall of the resist nozzle is cleaned.

0004

[Problems to be Solved by the Invention] In the conventional resist coating apparatus described above, solid matter on the inner wall of the resist nozzle is removed by discharging the resist itself. There were some things that could not be removed. Therefore, solid matter may suddenly be mixed into the resist, and the solid matter becomes a core, causing defects in which the resist film thickness varies linearly in the centrifugal direction within the wafer surface.

Local deterioration due to variations in resist film thickness causes changes in pattern dimensions. Therefore, before restarting the process after a long stop, it is necessary to completely remove the solid matter that has adhered to the inner wall of the resist nozzle.
This will reduce the yield and quality in the wafer photolithography process.

[0006]

[Means for Solving the Problems] A resist coating apparatus of the present invention is provided with a cleaning mechanism for cleaning a resist nozzle, the tip of which is adhered to a dried and solidified resist, with a solvent.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a cross-sectional view of the configuration of Example 1 of the present invention. A cleaning nozzle 2 and a drain tank 3 are provided around the cup 1 where the coating process is performed. A cleaning nozzle 2 is provided above the drain tank 3. First, as shown in FIG. 1, the resist nozzle 4 is moved close to the cleaning nozzle 2. A solvent is ejected from the cleaning nozzle 2 to clean the tip of the resist nozzle 4. When the set time is reached, stop spraying the solvent. Then, in order to drive out excess solvent components in the resist nozzle, the resist is drained from the resist nozzle 4 a set number of times. After that, the resist nozzle 4 is moved to the center of the chuck 7, and the wafer 8
is transferred onto the chuck 7, and a resist is dropped onto the chuck 7 to perform a spin coating process. When the product processing is completed and the waiting time until the start of the next processing exceeds about 1 hour, the tip of the resist nozzle 4 dries and solid matter is generated, so the above-mentioned resist nozzle cleaning is started. If it does not exceed about 1 hour,
The resist nozzle cleaning is not performed and the coating process begins immediately. However, since the time required for solid matter to be generated varies depending on the shape of the resist nozzle and the intensity of exhausting the cup, it is necessary to confirm the time interval for performing this cleaning depending on the conditions.

FIG. 2 is a cross-sectional view of a second embodiment of the present invention. A cleaning tank 5, a cleaning tank drive unit 6, and a drain tank 3 are provided around the cup 1 that performs the coating process. The cleaning tank 5 is driven up and down within the drain tank 3 by a cleaning tank drive unit 6. First, as shown in FIG. 2, the resist nozzle 4 is moved above the cleaning tank 5. During this time, a certain amount of solvent is supplied to the cleaning tank 5. Next, the cleaning tank 5 is raised so that the tip of the resist nozzle 4 can be immersed in the solvent. Further, the cleaning tank 5 is slowly moved up and down by the cleaning tank drive unit 6. As a result, solid matter adhering to the inner wall of the resist nozzle 4 is effectively removed. For example, if MEK (methyl ethyl ketone) is used, sufficient cleaning is possible by repeating this operation for about 30 seconds. Thereafter, the excess solvent component in the resist nozzle 4 is expelled in the same manner as in Example 1.

FIG. 3 is a cross-sectional view of a third embodiment of the present invention. This embodiment is a combination of embodiments 1 and 2, and includes a cleaning tank 5, a cleaning nozzle 2, a drain tank 3, and a cleaning tank drive section 6. The operation of this embodiment will be explained using the flowchart of FIG. First, the resist nozzle 4 is moved onto the cleaning tank 5. Next, the solvent is ejected from the cleaning nozzle 2, and when a set time has elapsed, the ejection is stopped and the cleaning tank 5 starts to swing. When the set time is reached, the swinging is stopped and the resist nozzle 4 is moved above the drain tank 3. Next, the resist is ejected from the resist nozzle 4, and when a set number of times is reached, the ejection is stopped. Next, the resist nozzle 4 is moved to the center of the chuck 7, and a resist coating sequence is performed on the wafer 8. When the waiting time limit until the start of product processing has been reached, the process returns to the above-mentioned resist nozzle cleaning operation.

0010

[Effects of the Invention] As explained above, the present invention cleans the surface and inner surface of the resist nozzle with a solvent before the coating sequence, and then replaces it with clean resist.
After the treatment is stopped, any solids generated by leaving the treatment can be completely eliminated. Therefore, it is possible to prevent the formation of solid matter at the tip of the resist nozzle, which is effective in improving product yield and reliability.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a configuration of Example 1 of the present invention.

FIG. 2 is a cross-sectional view of the configuration of Example 2.

FIG. 3 is a cross-sectional view of the configuration of Example 3.

FIG. 4 is a flowchart diagram of Example 3.

FIG. 5 is a configuration diagram of a conventional resist coating apparatus.

[Explanation of symbols]

1 cup 2 Cleaning nozzle 3 Drain tank 4 Resist nozzle 5 Cleaning tank 6 Cleaning tank drive unit 7 Chuck 8 Wafer 9 Spin motor 10 Drain hose

Claims (1)

[Claims] 1. A photoresist coating apparatus for a semiconductor device that coats a photoresist onto a semiconductor wafer, the apparatus comprising a mechanism for cleaning at least a photoresist nozzle with a solvent.