KR20010036694A - Coating method of wafer for fabricating semiconductor device - Google Patents

Abstract

PURPOSE: A photoresist coating method is provided to obtain a uniform thickness of photoresist layer without defects by uniformly coating a photoresist layer on a wafer through spraying a photoresist material while rotating the wafer in low and high speeds. CONSTITUTION: A wafer is loaded on a rotation chuck. A nozzle is located to the center of the wafer for spraying a photoresist material. The photoresist material is sprayed for 1 to 15 seconds through a nozzle fixed to a central position of the wafer while rotating the rotation chuck loaded with the wafer in a low speed of 50 to 250 rpm. The rotation chuck loaded with the wafer is rotated in a high speed of 200 to 5000 rpm. Then, a photoresist layer is formed on the wafer. The wafer is unloaded from the rotation chuck for next process.

Description

Coating method of photoresist on wafer for semiconductor device manufacturing {Coating method of wafer for fabricating semiconductor device}

The present invention relates to a photoresist coating method for a wafer for semiconductor device manufacturing. More specifically, the present invention relates to a photoresist coating method for uniformly applying photoresist onto a wafer by spraying the photoresist while rotating the wafer at a low speed.

Photolithography in the manufacturing process of a semiconductor device is to apply a photoresist to a wafer, transfer a pattern as previously designed, and develop it so that a substantial pattern by the photoresist is formed on the wafer. Next, it is one of the very important tasks to construct an electronic circuit through an etching process that is appropriately scraped according to the pattern of the photoresist formed on the wafer.

The photoresist used in the photolithography process serves to distinguish between a portion that should not be etched and a portion that should not be etched in a subsequent etching process, and a photosensitive polymer is used, and the photoresist polymer is used in the near ultraviolet region. Chemical and physical changes in a short time due to the action of light such as G-line, I-line, ultraviolet-ultraviolet or electron-beam or X-ray It can be a substance or composition which causes a change in solubility in a solvent.

In particular, the photoresist used in the manufacture of semiconductor devices should be capable of realizing a micron of less than micron, and also a material whose decomposition characteristics are changed due to decomposition or crosslinking reaction caused by light energy. In the present invention, a photoresist having the above photosensitivity is uniformly applied to the surface of a wafer used for manufacturing a semiconductor device, and a mask having a predetermined pattern formed thereon is placed thereon. By irradiating light having a predetermined level or more energy to the photoresist on the wafer due to the selective transmission of the light by the mask according to the pattern.

Therefore, uniform application of photoresist on the wafer can be considered a very important factor.

Conventional coating methods for applying photoresist on a wafer vary depending on the semiconductor device to be manufactured, but most of the photoresists are placed after placing a nozzle to inject the photoresist in the center of the stationary wafer. It was sprayed for a second, followed by further spraying the photoresist on the wafer for 2 to 3 seconds while rotating the wafer at a speed of about 700 rpm to allow the sprayed photoresist to be homogeneously applied onto the surface of the wafer.

However, such a conventional photoresist coating method includes a region where the photoresist initially sprayed in the stopped state of the wafer (hereinafter referred to as an 'super-foamed region') and a photoresist that is later sprayed in the wafer rotational state are used. Variations in the thickness of the photoresist between the coated areas (hereinafter referred to as 'late coating areas'), the difference in the bonding force between the photoresist and the surface of the wafer, or the volatility of the thinner contained in the photoresist. As a result, a circular defect occurred at a portion corresponding to the initial application region.

Defects such as circular defects may have a problem that affects subsequent phenomena and etching processes. That is, in the development, as both the initial application area and the late application area were developed in the same developing process, there was a problem in that the development degree was less developed and the initial application area was less developed. There is a problem that affects the yield and reliability of the resulting semiconductor device by causing a difference.

SUMMARY OF THE INVENTION An object of the present invention is to provide a photoresist coating method which enables the photoresist to be evenly coated on a wafer.

The photoresist coating method for a wafer for manufacturing a semiconductor device according to the present invention is different from applying the photoresist firstly while the wafer is stopped, and further applying the second photoresist while the wafer is continuously rotated. The photoresist is applied while rotating, and the wafer is then further rotated at high speed so that the photoresist is uniformly applied on the wafer.

Hereinafter, the present invention will be described in detail with reference to specific examples.

A photoresist coating method for a wafer for manufacturing a semiconductor device according to the present invention is a conventional applicator for applying photoresist, which is configured to load a wafer onto a rotary chuck and direct the nozzle toward the surface of the wafer to spray the photoresist. A photoresist coating method comprising: a wafer loading step of loading a wafer onto a rotary chuck; A nozzle adjusting step of placing a nozzle for spraying the photoresist at the center of the wafer; A low speed rotation step of spraying the photoresist for 1 to 15 seconds through a nozzle fixed to the center position of the wafer while rotating the rotating chuck loaded with the wafer at a low speed of 50 to 250 rpm; After the low speed rotation step is finished, a high speed rotation step of rotating the rotating chuck loaded wafers at a high speed of 200 to 5,000rpm; And an unloading step of unloading the photoresist-coated wafer from the rotary chuck for processing of a subsequent process such as a soft bake after the high-speed rotation step is completed.

The applicator can be easily understood by those skilled in the art to one of ordinary skill in the art can be purchased and used commercially by the leading manufacturers at home and abroad, the wafer is loaded on the rotary chuck And spray the photoresist by directing the nozzle towards the surface of the wafer.

The wafer loading step is a step of loading a wafer to be applied to the photoresist on a rotatable chuck, by rotating the wafer loaded on the rotary chuck to apply a centrifugal force to the photoresist injected onto the wafer to the surface of the wafer It serves to rotatably load the wafer so that it can evenly spread throughout.

The nozzle control step may be understood as a step of positioning a nozzle for ejecting the photoresist at a center or an arbitrary point of the wafer, and determining the ejection position of the photoresist.

Unlike the conventional photoresist coating method, the photoresist is sprayed for 1 to 15 seconds through a nozzle fixed at the center position of the wafer while rotating the rotating chuck loaded with the wafer at a low speed of 50 to 250 rpm in the low speed rotation step. It includes. In this step, the photoresist is sprayed onto the rotating wafer so that the photoresist does not stagnate on the wafer, so that there is no distinction between the initial application area and the late application area caused by the conventional photoresist coating method. do.

In the high speed rotation step, after the low speed rotation step is completed, the rotational chuck loaded with the wafer is rotated at a high speed of 200 to 5,000 rpm to perform a uniform photoresist on the entire surface of the wafer, and the thickness of the photoresist is performed. To adjust.

The expression of low speed or high speed in the low speed rotation step and the high speed rotation step is a relative concept of the rotation speed of the wafer in the low speed rotation step and the high speed rotation step in the present invention, and the low speed rotation step in the low speed rotation step in the high speed rotation step It means to rotate, in the high-speed rotation step is only to mean to rotate the wafer at a higher speed in the low speed rotation step, the rotation speed of the wafer does not mean an absolute. The rotational speed of the wafer may be determined in consideration of the type of semiconductor device to be manufactured, the physical properties of the photoresist used, in particular the viscosity, the thickness of the photoresist, and the like, which can be properly adjusted by those skilled in the art by repeated experiments. It can be.

In the unloading step, the wafer on which the application of the photoresist is finished is unloaded from the rotary chuck to enable the subsequent processing such as a soft bake on the photoresist-coated wafer.

In particular, the nozzles for the injection of the photoresist in the low-speed rotation step and the high-speed rotation step may not only be located at the center of the wafer, but also the edge of the wafer or at a point 1/3 to 1/2 from the center of the wafer. The photoresist may be sprayed while varying toward the center. As described above, by applying the photoresist while moving the nozzle from the edge of the wafer or the center of the wafer from a point of 1/3 to 1/2 toward the center, the effect of reducing contaminants remaining in the photoresist, in particular, This is considered to be due to the action similar to sweeping off contaminants that may remain on the surface of the wafer as the photoresist is sprayed once it reaches the surface of the wafer and is pushed out of the wafer by centrifugal force by the rotating wafer. .

In addition, in the high speed rotation step, the photoresist may be further injected for 1 to 5 seconds through a nozzle fixed to the center position of the wafer while rotating the rotating chuck loaded with the wafer at a high speed of 200 to 5,000 rpm. This is to adjust the thickness of the photoresist, such as supplying the photoresist sufficiently to obtain a thick film in the case of forming the thickness of the photoresist with a thick film or the like.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described.

The following examples are intended to illustrate the invention and should not be understood as limiting the scope of the invention.

Example 1

As a coater for conventional photoresist coating, the wafer is loaded on a rotary chuck for the application of the thick film photoresist, and the nozzle is directed toward the surface of the wafer to spray and apply the photoresist. Photoresist was applied using a commercial DNS-629 coater. First, the wafer is loaded onto the rotary chuck, and the nozzle for spraying the photoresist is positioned at the center of the wafer. The resist was sprayed for 12 seconds, and then the photoresist was further sprayed for 3 seconds through a nozzle fixed at the center position of the wafer while rotating the rotating chuck loaded with the wafer at a high speed of 200 rpm. Unloaded.

Example 2

Commercially available as a coater for conventional photoresist application, the wafer is loaded onto a rotary chuck for application of a thin film of photoresist, and the nozzle is directed toward the surface of the wafer to spray and apply the photoresist. The photoresist was applied using DNS-629 coater. First, the wafer is loaded on the rotary chuck, and the nozzle for spraying the photoresist is positioned at the center of the wafer, and then the rotary chuck loaded with the wafer is rotated at a low speed of 200 rpm to be fixed at one third from the center position of the wafer. After spraying the photoresist for 2 seconds through the prepared nozzle, the rotating chuck loaded with the wafer was continuously rotated for 26 seconds at a high speed of 4,610 rpm, and subsequently rotated for another 5 seconds at a high speed of 1,500 rpm. The applied wafer was unloaded.

Example 3

The photoresist-coated wafer was unloaded in the same manner as in Example 2 except that the position of the nozzle started from the edge of the wafer.

Comparative example

The photoresist was loaded using a commercially available DNS-629 coater as a coater for conventional photoresist application configured to load the wafer onto a rotary chuck and direct the nozzle towards the surface of the wafer to spray and apply the photoresist. Applied. First, the wafer is loaded onto the rotary chuck, the nozzle for ejecting the photoresist is positioned at the center of the wafer, and then the photoresist is moved through the nozzle fixed at the center position of the wafer while the rotary chuck loaded with the wafer is fixed. After spraying for 2 seconds, the photoresist is further sprayed for 2 seconds through a nozzle fixed at the center position of the wafer while rotating the rotating chuck loaded with the wafer at a high speed of 700 rpm, and then the wafer with the photoresist applied is unloaded. Loaded.

As a result of the synthesis of the above embodiments, it was confirmed that in the case of the photoresist coated wafer by the photoresist coating method according to the present invention, a photoresist film having a uniform thickness can be formed over the entire surface of the wafer. In particular, it could be confirmed that the circular defect shown in the conventional photoresist coating method shown in Comparative Example did not appear.

Therefore, according to the present invention, it is possible to obtain a photoresist film having a uniform thickness without generating defects such as circular defects, thereby improving the productivity of the semiconductor device and increasing the reliability of the obtained semiconductor device.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (3)

In the application of a photoresist using a coater for application of a conventional photoresist configured to load a wafer onto a rotary chuck, direct the nozzle towards the surface of the wafer and spray and apply the photoresist, A wafer loading step of loading the wafer onto the rotary chuck; A nozzle adjusting step of placing a nozzle for spraying the photoresist at the center of the wafer; A low speed rotation step of spraying the photoresist for 1 to 15 seconds through a nozzle fixed to the center position of the wafer while rotating the rotating chuck loaded with the wafer at a low speed of 50 to 250 rpm; After the low speed rotation step is finished, a high speed rotation step of rotating the rotating chuck loaded wafers at a high speed of 200 to 5,000rpm; And An unloading step of unloading the photoresist-coated wafer from the rotating chuck after the high-speed rotation step is completed for a subsequent process such as a soft bake; A photoresist coating method for a wafer for manufacturing a semiconductor device, characterized in that comprises a. The method of claim 1, In the low speed rotation step and the high speed rotation step, the nozzle for ejecting the photoresist is sprayed photoresist while varying toward the center of the wafer at a point of 1/3 to 1/2 from the edge of the wafer or the center of the wafer A photoresist coating method for a wafer for manufacturing a semiconductor device. The method of claim 1, The wafer for manufacturing a semiconductor device, wherein the photoresist is further sprayed for 1 to 5 seconds through a nozzle fixed at a center position of the wafer while rotating the rotating chuck loaded with the wafer at a high speed of 200 to 5,000 rpm in the high speed rotation step. Photoresist coating method.