JP3602164B2 - Development method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to lithography in a manufacturing process of a semiconductor device, and more particularly to a method for developing a photoresist film applied and exposed on a semiconductor substrate.
[0002]
[Prior art]
A conventional developing method will be described with reference to FIG. FIG. 4 shows steps for developing a substrate to be processed by a conventional developing method. This example is a method of developing a resist film by a paddle method.
[0003]
In FIG. 4A, the semiconductor substrate 1 on which the application and exposure of the resist film 2 has been completed is fixed on a rotatable vacuum chuck 3, and firstly from a developing solution nozzle 4 guided over the center of the semiconductor substrate 1. The developer 5 is dropped. Next, the developer 5 is spread over the entire surface of the semiconductor substrate 1 by rotating the vacuum chuck 3 at a low speed for a short time, and the developer 5 is filled by the surface tension.
[0004]
Next, in FIG. 4B, the rotation of the vacuum chuck 3 is stopped, and the development of the resist film 2 is performed for a predetermined time by the developing solution 5 laid on the semiconductor substrate 1. In the figure, reference numeral 6 denotes an opening from which the resist has been removed.
[0005]
Next, in FIG. 4C, the developing solution 5 is spun off by rotating the vacuum chuck 3 at a medium speed, and then pure water 8 is poured from a washing nozzle 7 guided over the center of the semiconductor substrate 1. Then, the developer 5 is washed off. In FIG. 4 (C), after washing with water for a predetermined time, the pouring of the pure water 8 is stopped, and the semiconductor substrate 1 is spin-dried by rotating the vacuum chuck 3 at a high speed. is there.
[0006]
[Problems to be solved by the invention]
However, in the conventional developing method, since the developing solution 5 in which the resist is dissolved cannot be sufficiently replaced by the rinsing solution (pure water 8), the resist remaining in the rinsing solution is pushed around the semiconductor substrate 1. And adhere to the semiconductor substrate 1 again. Then, there is a problem that the remaining resist adheres as particles on the dried semiconductor substrate 1. If the particles adhere in this manner, it causes a cause of poor quality of the semiconductor device in a subsequent process.
[0007]
Therefore, an object of the present invention is to provide a developing method capable of effectively preventing particles from adhering to a semiconductor substrate after a resist pattern is formed.
[0008]
[Means for Solving the Problems]
The developing method of the present invention includes a step of supplying a developing solution to a substrate on a spin chuck and holding the developing solution for a predetermined time; a step of supplying a rinsing liquid to the substrate while rotating the spin chuck at a first rotation speed; Rotating the spin chuck at a second rotation speed while the supply of the rinsing liquid is stopped, and rotating the spin chuck at a third rotation speed higher than the first and second rotation speeds; It is characterized by including.
Further, in the developing method of the present invention, immediately after the start of the supply of the rinsing liquid, before rotating the spin chuck at the second rotation speed, the fourth rotation speed higher than the first and second rotation speeds Characterized by including a step of rotating with.
Further, in the developing method of the present invention, the method further includes a step of rotating the spin chuck by continuously or stepwise increasing the rotation speed following the rotation at the third rotation speed.
[0009]
[Action]
According to the method of the present invention, when drying after rinsing, the number of rotations of the semiconductor substrate, which is a substrate to be processed, is continuously increased from a low speed, or is changed in two or more steps to increase the rotation speed. The resist on the substrate is pushed around it. This can prevent the resist from re-adhering to the semiconductor substrate, and can suppress adhesion of particles after development.
[0010]
【Example】
Hereinafter, a preferred embodiment of the developing method of the present invention will be described with reference to FIGS.
First, FIG. 1 shows a schematic configuration of a developing device 10 used in the method of the present invention. In the figure, 11 is a semiconductor substrate to be processed, 12 is a resist film on the semiconductor substrate 11, 13 is a rotating shaft arranged at a predetermined position in the developing device 10, and 14 is connected to the rotating shaft 13. A spin chuck 15 for holding 11, a developing solution 15 on the semiconductor substrate 11, a developing solution supply nozzle 16, and a rinsing solution supply nozzle 17.
[0011]
In the developing device 10, the semiconductor substrate 11 coated with the resist film 12 and selectively exposed is held by a spin chuck 14. In this state, an appropriate amount of the developer 15 is dropped onto the semiconductor substrate 11 from the developer supply nozzle 16 disposed above the spin chuck 14. Then, the developing solution 15 is applied on the semiconductor substrate 11 by surface tension as shown in the drawing, and then maintained in this state for a certain period of time, so that the resist film 12 is developed.
[0012]
After this development, the semiconductor substrate 11 is cleaned by rotating the spin chuck 14 while dropping pure water as a rinsing liquid from a rinsing liquid supply nozzle 17 disposed above the spin chuck 14.
[0013]
Here, FIG. 2 shows an example of a change in the number of rotations of the rotating shaft 13 when the spin chuck 14, that is, the semiconductor substrate 11 is rotated.
At the time of rinsing liquid supply, high speed rotation (first rotation speed) of about 1000 to 2000 rpm is performed as shown by the solid line in FIG. If the rotating shaft 13 is rotated at such a high speed for a long time during the supply of the rinsing liquid, particles adhere to the semiconductor substrate 11 due to rebound from the surroundings.
[0014]
Next, the number of rotations of the spin chuck 14 by the rotating shaft 13 is reduced to about 300 rpm, and cleaning with a rinsing liquid is subsequently performed. In FIG. 2, solid lines and dotted lines indicate the presence or absence of the supply of the rinsing liquid from the rinsing liquid supply nozzle 17.
After a lapse of a predetermined time, the dropping of the rinsing liquid from the rinsing liquid supply nozzle 17 is stopped, and in this stopped state, the rotation speed of the spin chuck 14 is about 300 to 500 rpm (the second rotation) as shown by the dotted line in FIG. Rotation speed). At this second rotation speed, particles adhering to the semiconductor substrate 11 are scattered.
Thereafter, the rotation speed of the spin chuck 14 is further increased from the second rotation speed to about 4000 rpm (third rotation speed), and thereby the semiconductor substrate 11 is dried. In this case, the third rotation speed is set higher than the first and second rotation speeds.
[0015]
Here, FIG. 3 shows an example of a change in the rotation speed of the spin chuck 14 in a comparative example with respect to the method of the present invention. In this comparative example, the development is performed by the developing device 10 according to the method of the present invention.
[0016]
The spin chuck 14 holding the semiconductor substrate 11 having the developed resist film on its surface is rotated at high speed (about 1000 to 2000 rpm) during the first few seconds by pure water as shown by a solid line in FIG. Washed. Subsequently, the spin chuck 14 is rotated at a rotation speed of 300 rpm for 46 seconds, and the semiconductor substrate 11 is washed with pure water. Thereafter, the semiconductor substrate 11 is dried by rotating the spin chuck 14 at a high speed of 4000 rpm.
[0017]
In this comparative example, the rinsing time was set to be much longer than that of the method of the present invention. Can be scattered. That is, in this comparative example, when the semiconductor substrate 11 is washed with pure water, the resist remaining (undissolved) in the developer 15 is expelled from the periphery of the wafer together with the rinse solution.
[0018]
In the method of the present invention, as shown in FIG. 2, after rinsing, particles on the surface of the semiconductor substrate 11 are scattered by rotating the spin chuck 14 at a rotation speed of about 300 to 500 rpm without a rinsing liquid. (Note that, when the semiconductor substrate 11 is rotated at a constant rotation speed as described above, particles on the surface thereof are easily scattered.) The time required for scattering particles is 6 seconds (see FIG. 2) in the method of the present invention, whereas in the comparative example, it is extremely long, 31 seconds between 18 seconds and 49 seconds. That is, according to the method of the present invention, the particle scattering time can be substantially reduced to 1/5.
[0019]
In the above embodiment, even if the rotation speed is other than the rotation speed (preferably, 500 rpm) of the spin chuck 14 in which the particles are easily scattered, the rotation speed is adopted if the particles can be substantially scattered. Is also good.
Further, the initial rotation speed is not limited to 300 rpm, and a developing solution laid by surface tension on the exposed semiconductor substrate 11 vacuum-adsorbed on the spin chuck 14 is rinsed with a rinsing liquid. When the rinsing liquid is dried while rotating the spin chuck 14 supporting the substrate, the rotation speed of the spin chuck 14 is increased from the rotation speed (faster than 0 and 1000 rpm or less) at which particles on the surface of the semiconductor substrate 11 can be scattered. The semiconductor substrate 11 may be raised in two or more steps to a rotation speed (3000 rpm or more and 3000 rpm or less) at which the semiconductor substrate 11 can be dried, or may be increased from low speed rotation to high speed rotation at an acceleration of 1000 rpm / sec or less.
[0020]
【The invention's effect】
As described above, according to the present invention, the resist dissolved in the developing solution in the lithography process does not re-attach to the substrate, and particles on the semiconductor substrate after the formation of the resist pattern can be reduced. The semiconductor substrate has advantages in that particles can be effectively prevented from adhering to the semiconductor substrate.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a developing device used in a method of the present invention.
FIG. 2 is a diagram showing an example of a change in the number of rotations of a rotating shaft when rotating a spin chuck according to the present invention.
FIG. 3 is a diagram illustrating an example of a change in the rotation speed of a rotating shaft in a comparative example of the present invention.
FIG. 4 is a diagram showing a schematic configuration of a developing device used in a conventional developing method.
[Explanation of symbols]
Reference Signs List 10 developing device 11 semiconductor substrate 12 resist film 13 rotating shaft 14 spin chuck 15 developing solution 16 developing solution supply nozzle 17 rinsing solution supply nozzle

Claims (3)

A step of supplying a developing solution to the substrate on the spin chuck and holding the developing solution for a predetermined time;
Supplying a rinse liquid to the substrate while rotating the spin chuck at a first rotational speed;
Rotating the spin chuck at a second rotation speed while the supply of the rinsing liquid is stopped;
Rotating the spin chuck at a third rotation speed greater than the first and second rotation speeds. Immediately after starting the supply of the rinsing liquid, before rotating the spin chuck at the second rotation speed, rotating the spin chuck at a fourth rotation speed higher than the first and second rotation speeds. The developing method according to claim 1, wherein 3. The method according to claim 1, further comprising a step of rotating the spin chuck by continuously or stepwise increasing the rotation speed following the rotation at the third rotation speed. 4.

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