JPH0590132A - X-ray aligner - Google Patents

Abstract

(57) [Summary] [Objective] An object of the present invention is to provide an X-ray exposure apparatus capable of obtaining high precision and high throughput. A temperature detecting element 1 for measuring a temperature change in the load lock chamber and a pressure in the load lock chamber in a load lock chamber in which an atmosphere is substituted for a wafer supply portion for supplying a wafer to the X-ray exposure apparatus main body and the exposure apparatus. He supply unit 3 with a temperature control function capable of supplying He at an arbitrary temperature to the pressure detection element 2 for measuring the temperature and the load lock chamber.
And the He supply valve 4 operated by PWM, and the PW
By providing the vacuum valve 5 operating at M, high precision and high throughput can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray exposure apparatus for performing exposure using X-rays such as synchrotron radiation (hereinafter abbreviated as SR).

[0002]

2. Description of the Related Art In recent years, SR has been used as a light source for a semiconductor exposure apparatus.
The use of such X-rays has been drawing attention. X-rays used for exposure are usually soft X-rays with a wavelength of about 1 nm, but soft X-rays in this wavelength range are attenuated extremely strongly, so in an X-ray exposure apparatus, the X-ray exposure path or the entire apparatus may be lost. It is common to seal with a closed container and fill the inside of the closed container with a gas such as He that allows easy passage of X-rays for exposure. Therefore, a wafer is supplied by a load lock system, a cassette containing the wafer is set in a load lock chamber, the chamber is once evacuated, and then He is supplied. Here, when the load lock chamber is once evacuated, adiabatic expansion occurs in the chamber and the temperature drops. The temperature of the wafer in the load lock chamber also drops, but in order to precisely align the relative position of the mask and the wafer with 1: 1 proximity exposure to the mask, thermal deformation due to the temperature change of the wafer is required. It is necessary to prevent it as much as possible or to allow a sufficient stabilization time for the thermally deformed wafer to return to its original state. For this reason, as shown in FIG. 2, conventionally, a method of arranging the heater 21 in the load lock chamber and supplying by a thermal heater taken away by adiabatic expansion has been adopted.

[0003]

However, the mechanism shown in FIG. 2 has the following problems.
That is, first, when the load lock chamber becomes close to a vacuum, the atmosphere as a medium for transferring heat disappears, and most of the heat generated from the heater affects the surrounding members in the form of heat transfer. That is, the wafer set in the cassette of the load lock is finally transmitted from the heater through the cassette. Therefore, heat is not easily transferred onto the wafer, and even if it is transferred, uneven temperature distribution occurs. In addition, there is a problem in that the temperature on the wafer cannot be determined even if the temperature of the loader, cassette, wafer, etc. is different and the heater is simply determined by the temperature of the main body of the exposure machine. Therefore, the overlay accuracy of the mask and the wafer is not improved, and it takes time to stabilize the temperature.

In order to solve the above problems, the present invention first changes the method of supplying heat from He so that the vacuum valve and the He introducing valve can be freely opened and closed depending on the temperature and pressure in the load lock chamber. The present invention provides a load lock chamber of an X-ray exposure apparatus having a function of suppressing the temperature change of the wafer as much as possible.

[0005]

In order to solve the above problems, a load lock chamber of an X-ray exposure apparatus according to the present invention is provided with a temperature detecting element, a pressure detecting element, and a He having a temperature adjusting function.
A supply unit, a valve that introduces He into the load lock chamber from the He supply unit and that can be operated by PWM, and the same PWM
It is characterized in that it is provided with a vacuum valve that can be operated at.

[0006]

The operation will be described below with reference to FIG. Figure 3
FIG. 3 is a simplified diagram of a load lock portion of the X-ray exposure apparatus of the present invention, where 30 is a load lock chamber, 31 is a load lock pressure detecting element, 32 is a loader, 33 is a cassette, and 34 is
Is the wafer. Further, 35 is a dummy wafer mounted for temperature detection, and 36 is a temperature detection element attached on the dummy wafer. Further, 37 is a portion for supplying He of an arbitrary temperature to the load lock chamber, and 38 is a PWM for that.
And a vacuum valve 39 also driven by PWM. When vacuuming is performed, the temperature in the room drops due to adiabatic expansion. At this time, the PWM duty ratio of the vacuum valve 39 is reduced to 38.
By increasing the duty ratio of the He supply valve of No. 2, it is possible to supply He at a higher flow rate and a smaller flow rate than that of being evacuated, thereby reducing the temperature decrease due to adiabatic expansion. The amount of heat of He supplied from the valve 38 is determined by the duty ratio of the vacuum valve 39 and the He supply valve 38, and this value may be determined from the pressure of the load lock chamber from 31 and the temperature on the dummy wafer 36. Yes, in this case it is even possible to perform the isothermal replacement operation.

As described above, according to the present invention, the temperature drop due to adiabatic expansion can be reduced and the temperature of the wafer can be uniformly changed by the above-mentioned structure. Further, the wafer temperature can be accurately measured, and even if the temperature on the wafer is different from that of the main body, it can be made the same in the minimum time.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A load lock of an X-ray exposure apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an X-ray exposure apparatus according to the first embodiment of the present invention. In FIG. 1, 1 is a temperature measuring element (in this case, a temperature measuring resistance element PT-100), and 2 is a pressure sensor. Further, 3 is a He supply unit capable of adjusting temperature,
4 is a He introducing valve that can be operated by PWM, and 5 is also P
It is a vacuum valve that can be operated by WM. Further, 6 is a wafer cassette, 7 is a wafer, 8 is a loader, 9 is a loader base, and 10 is an outer wall of a load lock. The operation of the load lock chamber configured as above when replacing He will be described below.

First, when He is replaced, the vacuum valve 5 is opened. That is, the duty ratio of PWM is increased.
Then, the pressure in the load lock chamber decreases, and the temperature also decreases due to adiabatic expansion. Here, the temperature of He to be supplied is increased as the temperature of the load lock chamber is decreased, and the PWM duty ratio of the He supply valve is increased as the pressure of the load lock chamber is decreased. At the same time, the PWM duty of the vacuum valve is increased. If the ratio is lowered, the pressure in the load lock chamber temporarily decreases gradually, and the temperature in the chamber also rises. As a result, it is possible to suppress the temperature change of the wafer in the load lock chamber as much as possible, and to find the optimum conditions through experiments such as the relationship between the difference between the wafer temperature and the He temperature to be supplied, the pressure for opening the valve, and the duty ratio. In other words, it is not impossible to change the temperature substantially isothermally during evacuation during the replacement.

As described above, according to this embodiment, the temperature detecting element, the pressure detecting element, and the H with the temperature adjusting function capable of setting the temperature of He to an arbitrary temperature are provided in the load lock chamber.
An e supply unit, a He introducing valve that operates by PWM, and a vacuum valve that also operates by PWM are provided, and by changing the PWM duty ratio of the He introducing valve and the vacuum valve according to the temperature and pressure inside the load lock chamber, It is possible to provide a load lock capable of suppressing the temperature change on the wafer in the load lock as much as possible.

[0012]

As described above, according to the present invention, since the temperature change of the wafer can be controlled to be small when the wafer load lock is replaced, the deterioration of the overlay accuracy of the mask and the wafer due to the temperature change can be prevented, and the temperature stability can be improved. Since the time required for the X-ray exposure can be reduced, high precision and high throughput can be expected for the X-ray exposure machine.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a load lock device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional load lock device.

FIG. 3 is a simplified block diagram of the load lock of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Temperature measuring element 2 Pressure sensor 3 He supply part capable of adjusting temperature 4 He introduction valve 5 Vacuum valve 6 Wafer cassette 7 Wafer 8 Loader 9 Loader base 10 Load lock outer wall 20 Load lock outer wall 21 Heater 22 Wafer cassette 23 Wafer 24 Air supply unit 25 He supply unit 26 Vacuuming valve 27 Loader 28 Loader base 29 Main chamber 30 Load lock chamber outer wall 31 Pressure sensor 32 Loader 33 Wafer cassette 34 Wafer 35 Dummy wafer 36 Temperature detection element 37 Temperature control He supply unit 38 He introduction Valve 39 Vacuum valve

Claims (1)

[Claims] 1. An X-ray exposure apparatus having a load lock chamber having a function of replacing an atmosphere as a wafer supply portion for supplying a wafer to an X-ray exposure apparatus main body, wherein a temperature detection element and a temperature detection element are provided in the load lock chamber. A pressure detection element, a He supply unit with a temperature control function, a valve that can operate by pulse width modulation (hereinafter abbreviated as PWM) that introduces He into the load lock chamber from the He supply unit, and also operates by PWM An X-ray exposure apparatus, which is provided with a possible vacuum valve.