JP2623608B2 - Resist removal method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method of removing a resist used for manufacturing a semiconductor device or the like.

[Summary of the Invention] The present invention relates to a method of removing a resist film in a ring shape along a wafer outer peripheral portion by dropping an organic solvent from a solvent dropping nozzle onto a wafer outer peripheral portion while rotating a semiconductor wafer coated with a resist film. In addition, wafer rotation speed, solvent discharge pressure,
By controlling the nozzle position and the like, the resist can be removed in a short time and with good finish.

[Prior Art] Conventionally, as a method of removing a resist film in a ring shape along an outer peripheral portion of a semiconductor wafer, the method shown in FIGS. 9 to 11 is known. That is, as shown in FIG. 9, a photoresist film 14 is formed by a spin coating method in which a photoresist is dropped on the upper surface of a wafer while the semiconductor wafer 12 is held and rotated by a wafer holder 10, and then the wafer 12 is rotated as shown in FIG. The organic solvent 18 is dropped from the solvent dropping nozzle 16 to the outer peripheral portion of the wafer while rotating at a constant rotational speed, thereby removing the photoresist film 14 in a ring shape along the outer peripheral portion of the wafer. Thereafter, as shown in FIG. 11, the wafer 12 is rotated in a state where the dropping of the solvent from the nozzle 16 is stopped, and the solvent is shaken off and dried.

[Problems to be Solved by the Invention] According to the conventional method described above, in the photoresist removing step of FIG. 10, since the photoresist is constantly dissolved from the thick portion of the photoresist film 14, the photoresist is thin as shown in FIG. There is a problem that the photoresist film 14A remains or the width D of the edge portion having an uneven thickness of the photoresist film 14 increases. Further, if the thin photoresist film 14A is to be eliminated, there is a disadvantage that the time for dropping the solvent is lengthened and the amount of the solvent used is increased.

[Means for Solving the Problems] An object of the present invention is to eliminate the above-mentioned inconveniences and to enable the resist to be removed in a short time and with good finish.

In the resist removal method according to the present invention, in the above-described resist removal step, for example, the wafer rotation is performed in order to reduce the spread of the dropped solvent toward the center of the wafer on the wafer as time elapses after the start of the solvent dropping. It is characterized by increasing the number or lowering the solvent discharge pressure.

[Operation] According to the method of the present invention, the spreading of the dripping solvent toward the center of the wafer is reduced as time elapses after the start of the solvent dripping, so that the resist constantly dissolves from the thick portion of the resist film. Disappears. Therefore, the eleventh
As shown in the figure, the thin resist film 14A does not remain or the width D of the edge portion of the resist film 14 does not increase, and the dripping time and the amount of solvent used can be reduced.

[Embodiment] FIGS. 1 to 4 show an embodiment of a resist removing method according to the present invention.

First, in the step of FIG. 1, a photoresist film 14 is formed by a spin coating method in which photoresist is dropped on the upper surface of a wafer while the semiconductor wafer 12 is held and rotated by a wafer holder 10. As an example, OFPR800 manufactured by Tokyo Ohka Kogyo Co., Ltd.
A photoresist was spin-coated to obtain a photoresist film 14 having a thickness of 1.16 [μm].

Next, in the step of FIG. 2, the organic solvent 18 is dropped from the solvent dropping nozzle 16 on the outer peripheral portion of the wafer while rotating the wafer 12 at a relatively low speed, so that the photoresist film 14 is formed into a ring shape along the outer peripheral portion of the wafer. Remove. As an example, the number of revolutions of the wafer was set to 100 [rpm], and acetone as an organic solvent was dropped from a nozzle 16 having a diameter of 0.2 [mm] for 3 seconds.

Next, in the step of FIG. 3, the solvent dropping from the nozzle 16 is continued while the wafer 12 is rotated at a relatively high speed. As an example, the wafer rotation speed was increased to 1500 [rpm], and acetone was dropped for 3 seconds.

Thereafter, in the step of FIG. 4, the wafer 12 is rotated while the dropping of the solvent is stopped, and the solvent is shaken off and dried. As an example, the wafer rotation speed was increased to 5000 [rpm], and rotation drying was performed for 10 seconds.

Thereafter, the wafer 12 is removed from the holder 10 and baked at, for example, 120 ° C. for 2 minutes using a hot plate oven or the like, thereby evaporating the solvent contained in the photoresist.

According to the above-described first embodiment, since the wafer rotation speed is increased during the removal of the resist, the centrifugal force is increased, and the spreading of the dripping solvent toward the center of the wafer is reduced. Therefore, as shown in FIG. 3, the photoresist on the outer peripheral portion of the wafer is completely removed, and the photoresist film 14 is removed.
Is cut cleanly, and the width D of the edge becomes narrower than before. Further, the dripping time and the amount of the solvent used can be shorter than before.

FIG. 5 and FIG. 6 show a second embodiment of the resist removing method of the present invention.

In the step of FIG. 5, following the photoresist coating step of FIG. 1, the organic solvent 18 is dropped from the nozzle 16 onto the outer periphery of the wafer while the wafer 12 is rotated at a predetermined number of revolutions, so that the photoresist film 14 is formed. Remove in a ring. In this case, the discharge pressure of the solvent from the nozzle 16 is set relatively high.

Next, in the step of FIG. 6, the discharge pressure of the solvent from the nozzle 16 is set relatively low, and the rotation of the wafer 12 and the nozzle 16
Continue to add solvent from.

Thereafter, the processing after the above-described drying step in FIG. 4 is performed.

According to the above-described second embodiment, since the solvent discharge pressure is reduced during the removal of the resist, even if the wafer rotation speed is constant, the spread of the dropped solvent toward the center of the wafer is reduced. Accordingly, as shown in FIG. 6, the photoresist on the outer peripheral portion of the wafer is removed cleanly, the edge of the resist film 14 is cut cleanly, and the width D of the edge becomes narrower than before. In addition, the time and amount of solvent dripping can be reduced.

FIG. 7 and FIG. 8 show a third embodiment of the resist removing method of the present invention.

In the step of FIG. 7, following the photoresist removing step of FIG. 1 described above, the photoresist film 14 is formed by dropping an organic solvent 18 from the nozzle 16 onto the outer periphery of the wafer while rotating the wafer 12 at a predetermined rotation speed. Remove in a ring.

Next, in the step of FIG. 8, the position of the nozzle 16 is moved away from the center of the wafer, and the rotation of the wafer 12 and the dropping of the solvent from the nozzle 16 are continued. In this case, the rotation speed of the wafer 12 is set high as in the step of FIG. 3, or the discharge pressure of the solvent from the nozzle 16 is set low as in the step of FIG.

 Thereafter, the processes after the above-described step of FIG. 4 are performed.

According to the third embodiment described above, the nozzle position is moved outward during the removal of the resist, and the wafer rotation speed is increased or the solvent discharge pressure is reduced. The spread of the solvent is reduced. Accordingly, as shown in FIG. 8, the photoresist on the outer peripheral portion of the wafer is removed cleanly, the edge of the resist film 14 is cut cleanly, and the width D of the edge is narrower than before. Further, the dripping time and the amount of the solvent used can be shorter than before.

The present invention is not limited to the above embodiment. For example, in the third embodiment, when the nozzle position is moved, the wafer rotation speed may be increased and the solvent discharge pressure may be decreased. In addition, increase in the number of rotations of the wafer,
The reduction of the solvent discharge pressure or the movement of the nozzle position may be performed continuously or stepwise. Furthermore, not only removal of so-called photoresist, but also electron beam resist,
The present invention is applicable to the removal of an X-ray resist or the like.

[Effects of the Invention] As described above, according to the present invention, the resist can be removed in a short time and with good finish, so that in the manufacture of a semiconductor device or the like, it is possible to improve the production yield and reduce the cost. Things.

[Brief description of the drawings]

FIGS. 1 to 4 are sectional views showing a first embodiment of the photoresist removing method according to the present invention, and FIGS. 5 and 6 are sectional views showing a second embodiment of the photoresist removing method according to the present invention. FIGS. 7 and 8 are cross-sectional views showing a third embodiment of the photoresist removing method according to the present invention, and FIGS. 9 to 11 are sectional views showing a conventional photoresist removing method. 10 wafer holder, 12 semiconductor wafer, 14 photoresist film, 16 solvent drop nozzle, 18 organic solvent.

Claims (2)

(57) [Claims] An organic solvent is dropped from a solvent dropping nozzle onto a peripheral portion of a wafer while rotating a semiconductor wafer having a resist film applied on an upper surface thereof, thereby removing the resist film in a ring shape along the peripheral portion of the wafer. In the resist removing method, the resist is characterized in that the number of rotations of the wafer is increased in order to reduce the spread of the dropped solvent toward the center of the wafer on the wafer as time passes after the start of the dropping of the organic solvent. Removal method. 2. An organic solvent is dropped from a solvent dropping nozzle onto a peripheral portion of a wafer while rotating a semiconductor wafer having a resist film applied on an upper surface thereof, thereby removing the resist film in a ring shape along the peripheral portion of the wafer. In the resist removing method, the discharge pressure of the organic solvent from the nozzle is reduced on the wafer in order to reduce the spread of the dropped solvent toward the center of the wafer over time after the start of the dropping of the organic solvent. A resist removing method characterized by the following.