JPH0254517A - Aligner and method of exposure - Google Patents

Abstract

PURPOSE:To assure a greater optical detection area and a setting space by forming a thorough-hole through an X-ray blocking section located rearwardly of an exposure region on an extension line extending in a direction of X-ray irradiation, said section being fixed to a guide or the like of a stage, and disposing an X-ray actinometer oppositely to and backwardly of said through-hole. CONSTITUTION:A through-hole 11 is provided through a stage guide 50 of an aligner 4 on an extension line extending in a direction of X-ray 3 irradiation. An X-ray actinometer 9 is fixed oppositely to and backwardly of the through- hole 11. There is no limitation to the actinometer 9 in the size of the same from the setting conditions of the same. Thereafter, a large-sized X-ray actinometer for controlling temperature of an X-ray sensitive-device may also be available.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an exposure apparatus and an exposure method using soft X-rays as a light source.

Conventional technology As semiconductor devices become more densely packed, exposure technology that uses (soft) X-rays, which have wavelengths two orders of magnitude smaller, has replaced the conventional exposure technology that uses ultraviolet light to form fine patterns in the submicron region. It is being considered.

In this Xf@ exposure, there is no appropriate refractive optical system for X-rays, so a reduction projection exposure method using a lens such as ultraviolet light cannot be used, and a mask of equal size is placed close to the semiconductor substrate. It is necessary to use a close exposure method.

In this proximity exposure method, it is necessary to irradiate the entire surface of the mask with X-rays perpendicularly. Furthermore, since there is no resist with high sensitivity and high resolution to X-rays, the intensity of X-rays must be high in order to obtain high throughput.

Synchrotron radiation light (SOR light) is an X-ray whose intensity is 100 times greater than that of an electron-excited point light source and whose parallelism is much better, making it the most suitable X-ray for X-ray exposure.

When performing X-ray exposure using this SOR light, the X-rays emitted by the electron trajectory being bent by a polarizing magnet in the SOR ring, where electrons are orbiting at a speed close to the speed of light, are , lead to the exposure device through a long port. The emitted X-rays have a narrow vertical width of several nanometers, so in order to increase the exposure area to, for example, 25 fi, a mirror is installed in the middle of the port, and by vibrating the angle of this mirror, the exposed surface can be exposed to X-rays. Expansion of the exposure area is being carried out using methods such as scanning.

Based on FIG. 2, X-ray exposure by the exposure device connected to the port will be explained.

1 is a port, 3 is an X-ray incident on an exposure device, 4 is an exposure device, 6 is a substrate holder of a ueno stage, θ is a Si substrate, 7 is a mask, and 9 is an x-scarlet light meter. Port 1
In the exposure area of the exposure device 4 connected to
They are juxtaposed with a distance of 0 μm.

The relative position of the mask 7 and 81 substrate 6 is determined by measuring the amount of deviation between the respective alignment marks by the alignment optical system 8, and correcting the relative positional deviation by moving the substrate holder 6. Ru.

Next, the shutter 10 is opened and the X-rays 3 are exposed to the mask y, Si
The substrate 6 is irradiated. At this time x#! As mentioned above, the beam 3 is reflected by the mirror installed in the port 1 at an angle of about 2 degrees from the horizontal, passes through the Be window at the tip of the port, and enters the exposure device 4. Due to the vibration of this mirror, the X The line 3 scans the surface of the mask 7 up and down, thereby irradiating a wide area, for example, a 26 square area.

The shutter 1o is opened for an exposure time set depending on the sensitivity of the resist applied to the surface of the Si substrate 6 and the intensity of the X-rays 3. The X-rays 3 entering the exposure device 4 enter the Be' window 2
The X-ray photometer 9 is placed between the mask 7 and the mask 7.

In the above-mentioned X-ray exposure, the X-rays 3 that are guided through the port 1 kept in a high vacuum and transmitted through the Be window 2 are highly attenuated in the atmosphere. It is necessary to shorten the X-ray optical path and increase the intensity at the surface of the Si substrate 6 as much as possible.

Problems to be Solved by the Invention However, the X-rays 3 incident on the exposure device 4 using the conventional method
To measure the intensity of
It was necessary to arrange the optical cover meter 9, and it was difficult to shorten the X-ray optical path.

Furthermore, the Be window 2 must be made thin in order to reduce the attenuation of the X-rays 3, and its mechanical strength cannot be increased. Therefore, in order for the X-ray photometer 9 to receive the X-rays without blocking the exposure X-rays, it is necessary to have a movable structure that exits onto the X-ray optical path only during measurement, making the structure of the X-ray photometer 9 complicated and This increases the size and makes the X-ray optical path even longer.

Furthermore, since the measurement is performed in front of the mask 7, the intensity of the X-rays attenuated by the mask 7 cannot be measured.

Means for Solving the Problems In the present invention, a through hole is provided in the xm-s contact part which is located on the extended line in the X-ray irradiation direction behind the exposure area and is fixed to a stage guide, etc. An exposure device is used in which an X-ray photometer is installed facing toward the rear.

Prior to exposing the semiconductor substrate, the substrate holding part of the stage is moved outside the exposure area, and the intensity of the X-rays that pass through the mask, pass through the through-hole, and reach the X-ray photometer is measured, and based on this intensity, Set the exposure time.

Thereafter, the substrate holder holding the semiconductor substrate is moved to the exposure area, the mask and the semiconductor substrate are aligned, and then exposed for a set time.

Function: The above-mentioned exposure apparatus has an X-ray photometer installed facing the through hole provided on the extension of the X-ray irradiation direction behind the exposure area, so the X-ray photometer has a sufficiently large light-receiving area for the X-ray photometer. The space between the installation windows can be secured, and at the same time, the distance between the Be window and the mask, that is, the X-ray optical path can be shortened.

Furthermore, the attenuation rate of the shutter can be determined by measuring the intensity of the X-rays after passing through the mask.

Example An embodiment of the present invention will be demonstrated below based on FIG.

In FIG. 1, 11 is a through hole provided in a fixed stage guide 6o.

A through hole 11 is provided in the stage guide 6o of the exposure device 4 on an extension line in the irradiation direction of the X-rays 3. Also, through hole 1
An X-ray photometer 9 is fixed behind the X-ray photometer 1 so as to face the through hole 11 . In the vicinity of the stage guide 6o of the exposure device 4, power lines and signal lines for the stage drive motor, cooling water piping for temperature control, etc. are arranged, and these pass through the through hole 11 to reduce the amount of X-ray light. It is placed in such a position that it does not block a total of 9 X-rays 3. There are almost no restrictions on the size of the X-ray photometer 9 due to its installation conditions, and a large X-ray photometer with a cooling mechanism for controlling the temperature of the X-ray sensing element can also be used. .

When performing X-ray exposure, first move the substrate holder 6 of the stage to the substrate mounting area, and place the resist-coated Si
The substrate 6 is held in the substrate holder 5 by vacuum suction or the like (FIG. 1b).

When the shutter 10 is opened for a predetermined period of time before the mask 7 is attached to the exposure area, the X-rays 3 pass through the through hole 11 of the stage guide 6o and reach the light receiving part of the X-ray photometer 9, since there is nothing blocking the exposure area. is irradiated and its intensity is measured. This confirms that the X-rays 3 guided to the exposure device 4 have sufficient intensity to carry out exposure.

Next, the shutter 10 is closed and the mask 7 is attached to the exposure area, and when the shutter 10 is opened again for the required time, the intensity of the X-rays 3 transmitted through the mask 7 is measured by the X-ray photometer 9. At this time, a part of the X-rays transmitted through the mask 7 is blocked by the absorber pattern made of a metal film such as W of the mask 7, and is also absorbed by a retaining film made of a Si3N4 film or a SiC film, so that the intensity of the X-rays increases. is smaller than without mask 7.

However, by comparing the X-ray intensity measured at this time with the previous X-ray intensity measured in the same way using a mask with the same pattern, it was found that the mask 7 to be used from now on was It can be confirmed that this is a normal mask with no rate reduction ring.

To carry out exposure, the shutter 10 is closed, the substrate holder 6 holding the resist-coated Si substrate 6 is moved to the exposure area, and the exposure chip of the Si substrate 6 is opposed to the mask 7 (see Fig. 1a). ). The positional deviation between the pattern of the mask 7 and the exposed chip pattern of the Si substrate 6 is detected using the alignment optical system 8, and the mask 7 and the Si substrate 6 are aligned by moving the substrate holder 5.

The shutter 10 is opened for a predetermined period of time to perform exposure to X-rays 3, and after the shutter 10 is closed, the substrate holder 6 is moved in steps to make the next exposure chip face the mask 7, position it, and start the exposure. I'll return it.

Note that while exposing one Si substrate, the X-ray photometer 9 is
Since ray 3 is not incident, measurement of X-ray intensity is not performed.

When the exposure of all the chips on the Si substrate 6 is completed, the substrate holder 6 moves to the substrate mounting area (FIG. 1b) and holds the next Si substrate to be exposed, replacing the exposed Si substrate. Attach it to section 6.

In the case of trial exposure, the exposed Si substrate is subjected to a development process, and a reference exposure time is determined based on the resist pattern formation result. When replacing this Si substrate, the shutter 10 is opened and the intensity of the X-rays transmitted through the mask 7 is measured with an X-ray photometer 9. By comparing this measurement value with the measurement value before trial exposure, it is possible to determine the
An appropriate exposure time is determined by understanding intensity fluctuations and correcting the reference exposure time as necessary.

FIG. 1 used to explain this embodiment shows the alignment optical system 8.
is near the exposure area and the distance between the B6 window 2 and the mask 7 is large. Be window 2 when aligning with
The distance between the mask 7 and the mask 7 can be made much smaller.

In addition, since the X-ray photometer 9 is located behind the mask 7 and 81 substrate 6, and the X-rays 3 are attenuated by the time they pass through the through hole 11 and reach the X-ray photometer 9, the measured The intensity is lower than the X-ray intensity on the surface of the Si substrate 6 during exposure, but the attenuation rate can be calculated in advance and a highly sensitive X-ray photometer 9 can be selected, so this is not a problem.

Furthermore, the exposure area expansion method is not based on mirror vibration;
Other methods can also be used, such as keeping the X-ray 3 fixed and moving the mask 7 and the S1 substrate 6 in alignment.

Note that since the through hole is formed on an extension line of the X-ray irradiation direction, it can also be used for optical axis alignment when connecting the port 1 and the exposure device 4.

Effects of the Invention According to the present invention, the exposure X reaching the mask from the tip of the boat
The optical path of the ray can be shortened, and the mask and Si substrate can be irradiated with X-rays of low attenuation and high intensity, so the X-ray exposure time can be shortened and the throughput can be increased. In particular, a greater effect can be obtained if the optical path can be further shortened by using a small-sized optical fiber in the alignment optical system or by detecting positional deviation outside the exposure area.

In addition, in order to measure the X-ray intensity after passing through the mask,
It is possible to understand not only the fluctuations in X-rays caused by the SOR ring, but also the fluctuations due to mask deterioration. Furthermore, when selecting an X-ray photometer, there is no restriction from the mounting position, and the optimal photometer for X-ray intensity measurement can be selected.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view for explaining an exposure apparatus and exposure method in an embodiment of the present invention, and FIG. 2 is a schematic plan view for explaining a conventional exposure apparatus and exposure method. 3...X-ray, 5...Substrate holding part of stage, 9...X-ray light meter, 11...Through hole in fixed part, 6o. ...Fixed part of the stage. Name of agent: Patent attorney Shigetaka Awano and 1 other person Boat Be book X Ori exposure front stage 1! Temporary monument Smu1 & plate mask position Kouito X-ray photometer (Town n51 Lii)

Claims (2)

[Claims] (1) A substrate holder that uses X-rays as a light source and moves out of the exposure area; a through hole located in the X-ray shielding part located behind the exposure area and extending in the X-ray irradiation direction; An exposure apparatus comprising an X-ray photometer installed opposite to the rear of a through hole. (2) A step of measuring the intensity of the X-rays transmitted through a mask attached to the exposure area, a step of determining the exposure time based on the measured value of the X-ray intensity, and a step of bringing the mask and the semiconductor substrate close to each other. an exposure method comprising the steps of arranging the X-rays in parallel and irradiating the X-rays for the exposure time.