JPH04206626A - Removal of peripheral resist - Google Patents

Abstract

PURPOSE:To remove a resist layer at the peripheral part of a wafer in a short time and surely by a method wherein a solvent is sprayed from a nozzle installed at the peripheral part of the wafer, the surface of a resist film at the peripheral part is removed, the peripheral part which has become thin is exposed to light and developed and the resist layer is removed. CONSTITUTION:A wafer 3 is vacuum-sucked and fixed onto a spin chuck 2 installed inside a hermetically sealed chamber 1. While it is being turned at high speed by using a motor M, a resist liquid is dropped from a nozzle 4; a resist film 5 in a thickness of about 3000 to 8000Angstrom is formed. Then, the spin chuck 2 is turned at low speed. A solvent for the resist film is sprayed from a nozzle 6; it is sucked to the direction of an arrow 7; the peripheral part 5A of the resist film is made thin. Then, the resist film 5A is exposed to light by using a peripheral exposure device 9. After that, a developing solution 10 is made to flow; it is sucked to the direction of an arrow 11; the resist film 5A remaining in the peripheral part is removed. Thereby, the peripheral part 5A of the resist film 5 formed on the wafer 3 is removed quickly and surely, and the yield of the title method can be enhanced.

Description

[Detailed description of the invention]

"Purpose of invention"

[Industrial application field]

The present invention relates to a method for removing resist from a peripheral area of a semiconductor wafer.

[Conventional technology]

During the semiconductor manufacturing process, a resist is applied onto the semiconductor wafer, and then exposed to light and developed in a predetermined pattern.
Furthermore, some materials undergo various processing steps such as etching. Semiconductor wafers coated with resist often come into contact with a transport mechanism or the like during transportation, causing the resist around the wafer to peel off and scatter, and the resist in the scattered portions to adhere to the semiconductor wafer, resulting in defective products. In particular, with the recent trend toward narrower exposure line widths and higher densities of wafers, a decrease in yield due to resist peeling has become a major problem. Therefore, a method has generally been proposed in which the resist around the semiconductor wafer is removed in advance. Known methods include a solvent removal method in which a solvent is sprayed onto the periphery to remove it, a method in which a gas is sprayed on the periphery to remove it, and a peripheral exposure method in which the periphery is exposed and removed.

[Problem to be solved by the invention]

However, the conventional wafer peripheral removal method described above is
In both cases, the surface layer of the resist around the wafer periphery decreases and the layer becomes thinner, but it is not completely removed, and the resist around the wafer periphery still peels off and scatters, and the resist in this scattered area adheres. Other issues remained. Moreover, it is difficult to remove the resist from the peripheral portion of the orientation flat portion of the semiconductor wafer, no matter which removal method is used. The present invention was developed in view of the above-mentioned circumstances, and provides a peripheral resist removal method that takes measures against dust generation. "Structure of the Invention" [Means for Solving Problem 111 1] In order to achieve the above object, the present invention supplies a resist solvent to the peripheral area after resist is applied onto a plate-like object to be coated to remove the resist in the peripheral area. This is a peripheral resist removal method comprising the steps of thinning the resist, exposing the peripheral portion after this step, and supplying a developer after this step.

[Function] In the present invention, after the resist is diffused over the entire surface of the wafer to form a resist film over the entire area of the wafer, a solvent is subsequently injected from a nozzle provided at the periphery of the wafer to form a resist film over the entire wafer surface. The surface of the resist film is removed to make it thinner, and then a peripheral resist is removed by performing an exposure and development process around the thinned area. In this way, since the peripheral resist has been removed to a certain extent by the solvent as described above, it becomes possible to more reliably remove the peripheral area in a short time through the wafer peripheral exposure and development process. [Example] Below, an example of the peripheral resist removal method according to the present invention will be described with reference to the drawings. In FIG. 1, inside a closed chamber 1. A spin chuck 2 which is rotated by a rotary motor in the direction of the arrow in the figure is provided, and the wafer 3 is vacuum-adsorbed onto the spin chuck 2 and temporarily fixed thereon. A rotary motor 15 is provided outside the chamber 1 to rotate the spin chuck 2 at a predetermined speed. A resist liquid application nozzle 4 is suspended from the upper center of the spin chuck 2, and a resist liquid 5 is dropped onto the surface of the wafer 3 from the tip of the nozzle 4, for example. The chuck 2 is rotated at high speed to form a resist 1li5 on the surface of the wafer 3 to a thickness of, for example, 3,000 to 8,000. A solvent such as ECA is mixed into the resist component of the resist liquid 5 to maintain the viscosity of the resist liquid 5 at a desired value, and the resist film is solidified due to the volatility of the solvent. A nozzle 6 for peripheral removal is provided at the upper peripheral position in the chamber l, and the spin chuck 2 is rotated at low speed (for example, lp
pm or less) and supply the above-mentioned resist film solvent from this nozzle 6 to the outer periphery side. For example, by spraying the solvent 1, the solvent is sucked in the direction of the arrow 7 shown in FIG. 1, and as shown in FIG. The surface layer of the resist solution 5 film at the periphery is removed to reduce the thickness of the resist film 5 at the periphery to be thinner than the thickness at the center, and the resist film at the periphery of the orientation flat portion 3A of the wafer 3 can also be made thinner. , the nozzle 6 at the orientation flat portion 3A.
is moved along the side edge. Next, in order to vaporize the solvent of the resist 5 on the wafer 3 and solidify the resist film, heat treatment is performed in the pre-baking process, which solidifies the surface of the peripheral resist 5A and makes it slightly thinner as shown in FIG. (x,>x,',
x2>x2'). The wafer 3 coated with the resist film as shown in FIG. 4 is subjected to peripheral exposure and development steps. Specifically, as shown in FIG. 5, a peripheral exposure device 9 is provided around the periphery of the wafer 3 temporarily fixed on the chuck 8, and after exposing the resist 5A in the peripheral area while rotating the chuck 8, the wafer 3 is exposed. Supply the developer as shown by arrow 10, and then
The developing solution is sucked so as to flow in the direction shown in 1, and the remaining peripheral resist SA is reliably removed in the peripheral area. In this case, as described above, since the peripheral resist has been removed to some extent in the developing process, the peripheral removal process can naturally be executed in a short time. By these two steps, the peripheral removal boundary can be removed neatly. Next, the process of removing the periphery of the resist will be mainly explained. The wafer 3 is suctioned and fixed on the spin chuck 2 in the closed chamber 1, and then the nozzle 4 is brought close to the center of the wafer 3 and the resist 5 is dropped.When the wafer 3 is rotated at high speed, the resist 5 is removed by centrifugal force. A resist film is formed over the entire surface of the wafer 3 by diffusing it over the entire surface of the wafer 3. Next, in this chamber 1, a solvent is injected from a nozzle 6 provided at the periphery of the wafer 3 to remove the surface portion of the resist at the periphery of the wafer 3 to thin only the periphery. The surface of the peripheral resist 5A is solidified together with the resist film in the area. As described above, since the resist around the periphery is thinned to a certain extent by the solvent, it is possible to reliably remove the periphery in a short period of time by exposing the wafer 3 to light around the wafer 3 and developing the resist. "Effects of the Invention" As is clear from the above, according to the present invention, the resist in the peripheral area of the semiconductor wafer can be reliably removed in a short time.
This has the effect of improving yield.

[Brief explanation of the drawing]

The drawings show one embodiment of the peripheral resist removal method of the present invention, and FIG. 1 is a front explanatory view showing the solvent removal process;
Fig. 2 is a partial cross-sectional view showing the state after removing the peripheral resist same as above, Fig. 3 is a plan view showing the wafer, Fig. 4 is a partial cross-sectional view showing the state after the pre-bake process, and Fig. 5 is the surrounding area. FIG. 3 is a partial front view showing an exposure and development process. 1...Chamber 2...Spin chuck 3...
...Wafer 5...Resist 5A...Peripheral resist 6...Nozzle 9...Peripheral exposure machine Patent Applicant Tokyo Electron Ltd. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) A step of thinning the resist in the peripheral area by supplying a resist solvent to the peripheral area after applying the resist onto the plate-shaped object to be coated;
A peripheral resist removal method comprising the steps of: exposing the peripheral area after this step; and supplying a developer after this step.