JPH02103919A - Aligner - Google Patents

Abstract

PURPOSE:To enable acryloid photoresist to be patterned stably by introducing inert gas through a gas introduction part into closed space which is formed in the vicinity of a sample by a sample base, a sample base sidewall, and a mask, and exhausting air to the outside. CONSTITUTION:A sidewall 11 is erected around a sample base 10, and sealed space 12 is formed which is surrounded by this side wall 11 and the mask 9 being held to a mask holder 8 by vacuum chuck. When inert gas is introduced into the closed space 12 from a gas introduction port 15, the inert gas fills in the space 12 while expelling air in the space 12 from an exhaust port 16. A sample 13 which is chuck by vacuum onto the sample base 10 and on which photoresist is applied is exposed to the light through the mask 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an exposure apparatus for resists and the like in photolithography processes necessary for manufacturing semiconductors, electronic devices, and the like.

2. Description of the Related Art Heretofore, as an exposure apparatus of this type, one shown in FIG. 2, for example, has been known. This figure shows the optical system of a contact type exposure apparatus. Light emitted from a light source 1 is converted into parallel light by a lens 2, reflected by a mirror 3, passes through a mask 5 held by a mask holder 4, and is irradiated onto a sample 7 placed on a test tilt table 6.

Although not shown, a highly sensitive photoresist such as an acrylic photosensitive resin is coated on the sample 7. In the case of the contact method, there is no gap between the mask and the sample, but when contact is made in an oxygen atmosphere, oxygen is taken into the irregularities on the surface of the mask and sample, and polymerization is inhibited by this oxygen.

That is, there is a disadvantage that radicals generated from an initiator in the resist during exposure combine with oxygen molecules that have penetrated and diffused into the photoresist from the surrounding air, and do not contribute to the polymerization of the monomer.

Therefore, it is necessary to prevent oxygen from penetrating and diffusing into the photoresist.

Currently, as a countermeasure for this, a resist is applied to the glass base material of the substrate or the semiconductor substrate, and then a resin such as polyvinyl alcohol is applied as an oxygen barrier film on top of this, or an inert gas such as nitrogen is sprayed onto the resist. However, it is exposed to light.

Problems to be Solved by the Invention By attaching an oxygen barrier film to a photoresist in this manner, patterning can be performed with low exposure power. However, by adding an oxygen barrier film, (1) peeling of the photoresist after exposure due to insufficient wetting between the photoresist and the oxygen barrier film, and (2) blurring of the mask pattern image (decreased resolution due to the thickness of the oxygen barrier film). ), and the most important problem is that (3) an oxygen barrier film coating process (including pre-baking) is required, leading to high equipment costs. Further, in the case of exposure while blowing an inert gas such as nitrogen, if the gas replacement is insufficient, the polymerization will be damaged by the influence of residual oxygen and defects will easily occur.

In view of the above-mentioned problems, the present invention provides
It is an object of the present invention to provide an exposure apparatus that can stably pattern the acryloid photoresist by creating an inert gas atmosphere with sufficient oxygen blocking.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a sample stage on which a substrate coated with a photoresist is placed and a mask for selectively irradiating light from a light source. In an exposure apparatus having a mask holder for holding, a side wall is provided around the sample stage to form a substantially closed space surrounded by the side wall, the mask, and the sample stage, and to replace the surrounding air within the space. The sample stage is characterized in that a gas introduction hole for introducing an inert gas for the purpose of cleaning, and an exhaust hole for discharging the gas from inside the space to the outside are formed in the sample stage.

The side wall is movable up and down so as to come into contact with or separate from the mask, and is preferably driven by the gas pressure of an inert gas introduced into the substantially closed space to replace the atmosphere within the space. Further, it is preferable that the side wall or the contact portion between the side wall and the mask be formed of a material softer than a thin film such as metal forming the mask pattern.

According to the present invention, inert gas is introduced from the gas introduction hole into the substantially closed space formed around the sample by the sample stand, side wall of the sample stand, and mask, and gas such as nitrogen in the space is removed from the exhaust hole. Since the space is filled with an inert gas by discharging it to the outside, exposure can be performed in a state where surrounding air containing oxygen that inhibits polymerization is blocked. Therefore, during exposure, the radicals generated from the photoinitiator in the resist do not bond with oxygen molecules, but bond with the monomer that is the photopolymerizable material, allowing highly accurate exposure. Since the mask and the side wall of the sample table are in airtight contact, the inert gas formed in the groove in the nearly closed space will not flow out to the outside, so the atmosphere in the nearly closed space can be quickly created with a small amount of inert gas. can be replaced.

Furthermore, since the side wall is movable up and down, it can be lowered and separated from the mask during alignment, making alignment easier, and a substantially closed space can be easily formed by raising it during exposure.

The vertical movement of the side wall can be driven by using the gas pressure of the inert gas introduced to replace the atmosphere in the nearly closed space, so it is not only possible to push up the mask uniformly, but also to The structure of the device is simplified.

Furthermore, since the side wall or the contact portion between the side wall and the mask is made of a material that is softer than the thin film such as metal that forms the mask pattern, the mask does not move even if the side wall and the mask are aligned and are in contact with each other. The pattern is not scratched, and the pixels formed after exposure are not adversely affected.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

A side wall 11 is erected around the sample stage 10 to form a substantially closed space 12 surrounded by this side wall, the sample stage 10, and the mask 9 held by the mask holder 8 by vacuum suction. The sample stage 10 includes a gas introduction hole 15 for introducing an inert gas such as nitrogen gas into the substantially closed space 12 and an exhaust hole 16 for discharging gas such as oxygen in the road wall space to the outside. will be established. Note that 13 is a sample such as a glass substrate whose surface is coated with a photoresist.

Further, the side wall 11 can be moved so that it can be lowered during alignment to separate it from the mask, and after the alignment is finished, raised and brought into contact with the mask to form a substantially closed space.

For example, as shown in the figure, the lower piston rod section 18 is arranged to move up and down in a cylinder section 17 provided around the sample stage 13, and the inert gas introduced into the substantially closed space 12 is A part is the cylinder part 17 and the substantially closed space 1
It is connected to the inside of 2. Therefore, the cylinder portion 17
The piston rod portion 18 of the side wall 11 is moved up and down by the pressure of the inert gas flowing into the side wall 11, and the side wall 11 is driven up and down. Since the side wall 11 is configured in this way, it is not only possible to push up the mask uniformly, but also to maintain contact with the mask with a constant strength regardless of the top or bottom of the sample stage 10.

In this embodiment, the side wall 11 is lowered during alignment, and after the alignment is completed, an inert gas is fed into the sample stage 10 and the side wall is pressed against a mask to form the space 12. However, the side wall 11 or the side wall It is also possible to align the side wall 14 and the mask 9 while keeping them in contact by forming the contact portion 14 between the side wall 11 and the mask with a material that is softer than the thin film such as metal forming the mask pattern. Furthermore, if the mask is small, it is also possible to bring the side wall 11 into contact with the mask holder 8 to form the space.

In the above embodiment, the inert gas blown into the substantially closed space from the gas introduction hole 15 is used to direct the air in the space 12 to the exhaust hole 1.
6 and fills the space 12. If the side wall work 4 is not provided, a part of the inert gas discharged from the gas introduction hole 15 will flow into the space 12, and the rest will flow outside. Particularly when the gap between the mask and the sample is narrow, most of the gas will flow out to the outside, but by providing the side wall 14, the outflow to the outside can be suppressed, and a small amount of inert gas can be used.
It becomes possible to replace the atmosphere in the substantially closed space in a short time, and furthermore, it becomes possible to sufficiently reduce the residual oxygen concentration in the substantially closed space.

When the exposure apparatus of the present invention having the above configuration was actually used, for example, nitrogen gas was blown into the substantially closed space 12 from the large gas guide hole 15 at a rate of 5 ff/min for about 1 minute to cool the internal atmosphere of the space. After purging with nitrogen gas, a sample (glass substrate) 13 coated with photoresist vacuum-adsorbed onto the sample stage 10 was brought into contact with the mask 9 and exposed. After exposure, development was performed after being held in a nitrogen atmosphere for about 1 minute, and a developed surface with much higher precision than that obtained using conventional exposure means was obtained.

Effects of the Invention By using the exposure apparatus of the present invention, there is no need to coat an oxygen barrier film on the photoresist (the manufacturing time can be shortened, the number of coating equipment can be reduced, and the amount of inert gas used can be reduced). Since the oxygen concentration in the inert gas atmosphere can be reduced, a low-cost and highly reliable process can be constructed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an exposure apparatus of the present invention, and FIG. 2 is an explanatory diagram of a conventional general exposure apparatus. 8...Mask holder 9...Mask, 10.
... Sample stand, 13... Sample, 11... Side wall,
12...Substantially closed space, 15...Gas introduction hole, 16
...Exhaust hole.

Claims (4)

[Claims] (1) In an exposure apparatus that has a sample stand on which a substrate coated with photoresist is placed and a mask holder that holds a mask for selectively irradiating parallel light from a light source, a side wall is provided around the sample stand. This forms a substantially closed space surrounded by the side wall, the mask, and the sample stage, and also includes a gas introduction hole for introducing an inert gas to replace the atmosphere in the space, and a gas introduction hole for introducing an inert gas from inside the space to the outside. An exposure apparatus characterized in that an exhaust hole for discharging air is formed in the sample stage. (2) At the time of alignment, the side wall is lowered and separated from the mask, and at the time of exposure after alignment, the side wall is raised and brought into contact with the mask, so that the side wall can form a substantially closed space surrounded by the side wall, mask, and sample stage. 2. The exposure apparatus according to claim 1, wherein the exposure apparatus is movable up and down. (3) The exposure apparatus according to claim 2, wherein the side wall is driven by the gas pressure of an inert gas introduced into the space to replace the atmosphere within the substantially closed space. (4) The exposure apparatus according to claim 1, wherein the side wall or the contact portion between the side wall and the mask is formed of a material softer than a thin film such as metal forming the mask pattern.