JPS6217851B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resist coating device for coating a photoresist onto a substrate surface.

When manufacturing a semiconductor device, processes of selectively diffusing impurities into a semiconductor substrate and selectively etching are repeated many times. PEP process (Photo) is used for selective diffusion and selective etching.
In order to perform the PEP process, photoresist must be applied extremely thinly and uniformly to the surface of the semiconductor substrate. On the other hand, PEP is also performed when creating a photomask (a mask for selectively exposing the coated photoresist film) used for PEP accompanying the selective diffusion and selective etching, and in this case, for example, glass It is required to apply a very thin and uniform photoresist to the surface of a substrate or the like.

FIG. 1 is an explanatory diagram showing a conventional resist coating method. In the figure, 1 is a main body of a resist coating device called a spinner. A cavity 2 for vacuum suction is formed inside the spinner 1. A substrate, for example a rectangular glass substrate 3, whose surface is coated with a resist, is placed on the spinner 1 and is firmly held by vacuum suction through the cavity 2. In this state, a photoresist 4 is dropped onto the glass substrate 3,
When the spinner 1 and the firmly held glass substrate 3 are rotated, the dropped photoresist spreads from the center to the periphery of the glass substrate 3 due to centrifugal force, and is uniformly spread over the surface of the glass substrate 3 in an extremely thin layer. It is applied to a certain thickness.

However, if a photoresist with a molecular weight of 100,000 or more or a viscosity of 40cps or more is applied using the above method, the droplets of photoresist blown away by the rotation of the glass substrate become like long strings, as shown in Figure 2. . Moreover, as shown in the same figure, when the photoresist is scattered from the corner A of the glass substrate 3 at the rotation position indicated by the broken line and the glass substrate 3 is rotated to the solid line position while the thread is being pulled, this thread 4' is placed on the glass substrate 3. I often get carried away. The photoresist film coated on the glass substrate 3 is extremely thin, about 5000 Å thick, whereas the threads produced by the stringing phenomenon of the scattered photoresist are so thick that they can be clearly seen with the naked eye. Therefore, even if exposure and development are performed, the portion to which this thread is attached will be insufficiently exposed, resulting in defects in the formed pattern.

In this case, the resist solvent concentration in the surrounding atmosphere was varied from zero to saturated concentration, but the stringing phenomenon was not affected. I have also tried placing a ring or a rod around the rotating substrate to untangle the threads, but this has not had much effect, and in fact, this has caused more stringing.

The stringing phenomenon described above similarly occurs when photoresist is applied to the surface of a semiconductor wafer.
Further, some resist coating apparatuses are equipped with a spinner that holds the substrate mechanically without using vacuum suction, but even when such resist coating apparatuses are used, the stringing phenomenon similarly occurs.

The present invention was made in view of the above circumstances, and
The present invention provides a resist coating device capable of uniformly coating a resist without attaching threads generated by scattering of the resist to the surface of a substrate.

Embodiments of the present invention will be described below with reference to FIGS. 3 and 4.

FIG. 3A is a plan view showing a spinner of a resist coating apparatus according to an embodiment of the present invention, and FIG.
is a sectional view taken along the line BB. In these figures, 11 is the base of the spinner. A rotating shaft 12 is integrally attached to the back surface of the base 11. Furthermore, four arms 13 ₁ to 13 ₄ are fixed to a portion of the rotating shaft 12 near the back surface of the base 11 . Base stops 14 ₁ to 14 ₄ having an L-shaped cross section are protruded from each of the arms _{13 1} to 13 ₄ , and the mask glass substrate 15 placed at the position indicated by the imaginary line in the figure is attached to this base stop. 14 ₁ to 14 ₄ and held. On the other hand, arms 13 ₁ to 13 ₄
An annular wall 16 that surrounds a glass substrate 15 placed thereon is fixed to the tip of the glass substrate 15 . The wall body 16 is provided so as to be inclined so as to widen toward the end.

If, for example, a rectangular glass substrate 15 is placed at the position shown by the imaginary line in the figure of the spinner having the above configuration and the spinner is rotated, the glass substrate 15 is held by the substrate stops 14 ₁ to _{14 4} . Rotates with the spinner. In this way, the glass substrate 1
When applying photoresist by dropping it onto the surface of the glass substrate 15 while rotating the glass substrate 15, even if the photoresist pulls strings from the periphery of the glass substrate 15 (usually the four corners) and scatters, the scattered photoresist will not be scattered around the surrounding area. The wall 16 rotating at the same angular velocity
The situation is captured and no further action is taken. At this time, if the wall 16 is inclined to widen toward the end as described above, the captured drops of photoresist will fall along the wall surface. Therefore, it is possible to prevent the droplets of photoresist from further pulling a thread from the upper end of the wall body 16 and scattering, and from adhering the thread to the glass substrate 15. Even if the captured droplets of photoresist pull a string from the lower end of the wall 16 and scatter, the lower end of the wall 16 extends below the glass substrate 15, so in this case, the thread will not be attached to the glass. It does not adhere to the resist-coated surface of the substrate 15. Note that the diameter of the annular wall body 16 is the same as that of the glass substrate 1.
It is desirable to make it as small as possible so as not to touch 5.

FIG. 4A is a plan view showing a spinner of a resist coating apparatus according to another embodiment of the present invention, and FIG. 4B is a sectional view taken along the line BB. In this embodiment, the wall is not inclined but is vertically arranged and is divided into four parts. The divided individual arc-shaped walls 16 ₁ ′ to 16 ₄ ′ are connected to the arms 13 ₁ to 1
3 _{and 4} , respectively. Then, it is placed at the position shown by the imaginary line in the figure, and the base stoppers 14 ₁ to 1
The four corners of the glass substrate 15, which is fixed to the glass substrate ₄₄ , extend outward from the gaps between the arcuate walls ₁₆₁ ' to ₁₆₄ '. All other configurations are the same as the embodiment shown in FIG.

By the way, when applying photoresist to the surface of the rectangular glass substrate 15 while rotating it with a spinner, the drops of photoresist will be applied to the glass substrate 15.
Scattered from the four corners. Therefore, when photoresist is applied using the spinner having the above-mentioned structure, drops of photoresist are scattered from the four corners of the glass substrate 15 to the outside of the walls 16 ₁ ′ to _{16 4} ′. As a result, the threads formed by the scattering of the photoresist are blocked by the walls 16 ₁ ′ to _{16 4} ′ and
It does not adhere to the glass substrate 15 within ₁ ' to ₁₆₄ ', and an excellent photoresist film can be formed as in the embodiment shown in FIG. 3.

In addition, in all the above-mentioned embodiments, the substrate stops 14 ₁ to 1
_4. The glass substrate 15 is fixed on the spinner by being locked by the spinner.
Of course, it is also possible to fix the spinner 5 on the spinner base 11 by vacuum suction.

Furthermore, the resist coating apparatus shown in the embodiment of FIG. 4 can only be applied to rectangular substrates, such as the glass substrate of a photomask, whereas the resist coating apparatus shown in the embodiment of FIG. It can also be applied to the case of coating a photoresist on the surface of a substrate. In this case, vacuum suction is preferred as the method for fixing the substrate on the spinner.

As detailed above, the resist coating apparatus of the present invention prevents threads formed by the stringing phenomenon of photoresist drops scattered from the periphery of the substrate from adhering to the photoresist coated surface of the substrate. It is possible to produce a remarkable effect in that a photoresist pattern without defects can be formed.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the method of applying photoresist using a spinner, and Fig. 2 shows the stringing phenomenon of photoresist scattered from a rotating glass substrate.
An explanatory diagram showing how the threads thus formed adhere to the resist-coated surface of the glass substrate, FIG. 3A
3 is a plan view showing a spinner of a resist coating apparatus according to an embodiment of the present invention, and FIG.
FIG. 4A is a plan view showing a spinner of a resist coating device according to another embodiment of the present invention; FIG. 4B is a cross-sectional view taken along line B--B in FIG. 4A. . 11... Spinner base, 12... Rotating shaft, 1
3 ₁ - 13 ₄ ... Arm, 14 ₁ - 14 ₄ ... Base stopper, 15 ... Glass substrate, 16, 16 ₁ ' - 1
6 ₄ '...Wall body.

Claims (1)

[Scope of Claims] 1. A spinner that holds and rotates a substrate to which a resist is to be applied; and an annular wall that is provided around the spinner and rotates together with the spinner; The interior angle formed by the main surface of the spinner base is an acute angle, the upper end thereof is located above the main surface of the base body held by the spinner, and the lower end thereof is located above the main surface of the base body held by the spinner. A resist coating device characterized in that the resist coating device is installed so that the resist coating device is positioned below the resist coating device. 2. A patent claim characterized in that the wall provided around the spinner is divided into parts in order to extend the corner of the base fixed to the spinner where the resist is likely to scatter to the outside of the wall. The resist coating apparatus according to item 1.