JP2003229347A - Semiconductor manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact temperature control means of high precision in a vacuum, and also to provide an aligner comprising the temperature control means. <P>SOLUTION: The aligner uses an EUV light source for exposure in a vacuum to bake a minute pattern. An electrostatic chuck is used to secure a work piece such as wafer in a vacuum, only to generate heat by the electrostatic chuck. If it is cooled directly, vibration for cooling is transmitted to the wafer, resulting in the degraded positional accuracy of a pattern. A radiating board supported not to contact the chuck is provided as a countermeasure, and the temperature of the radiant board is set to a low value so that a sufficient amount of heat is moved from the chuck to the radiant boards at all times. Further, the chuck is provided with a heating body and a temperature-measuring means to control a temperature by controlling the amount of heat applied to the heating body. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor exposure apparatus that operates in a vacuum and a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art FIG. 8 shows a conventional semiconductor exposure apparatus used in the atmosphere. Lighting system, mask stage system, projection system,
It consists of a wafer stage. The mask stage system and the projection system are generally supported by a main body system (not shown).

FIG. 9A shows a perspective view of the entire wafer stage. A fine movement stage capable of moving a small stroke in the 6-axis directions of XYZωxωyωz is mounted on a coarse movement stage that moves a long stroke in the XY plane, and a wafer chuck is placed on the fine movement stage and a wafer chucked is not shown. The exposure system prints the pattern of the original plate. A vacuum chuck is used as the chuck.
The position of the fine movement stage is measured and controlled with high accuracy by a laser interferometer irradiated on the mirror.

It is desirable that the fine movement stage controls six axes by a linear motor, particularly a Lorentz force type linear motor. When the fine movement stage is controlled by a Lorentz type linear motor, the vibration from the coarse movement stage is insulated, and the most precise control is possible.

Coarse movement stages include those having a so-called cross-shaped configuration and a planar motor configuration in addition to the two-stage overlapping configuration. A linear motor is generally used as the driving means.

The heat sources in the conventional example are the linear motor for driving the coarse moving stage, the linear motor for driving the fine moving stage, and the exposure heat from the exposing means (not shown).

When heat is generated from the heat source, the air density in the optical path of the laser interferometer is changed to deteriorate the measurement accuracy, and the coarse movement stage and the fine movement stage are deformed by heat, and the wafer is distorted or the measurement reference is distorted. Both degrade the accuracy of the pattern printed.

As a countermeasure against this, as shown in FIGS. 9B and 9C, a coarse linear motor and a fine linear motor are provided with a jacket, and a refrigerant is circulated through the jacket to remove heat generated from the motor coil. Even so, heat generated by leaking out of the jacket is removed by circulating temperature-controlled air throughout the exposure atmosphere.

A sectional view of the fine movement stage linear motor is shown in FIG.
(B), a cross-sectional view of the coarse motion linear motor seen from above is shown in FIG.
(C) of.

On the other hand, since the heat from the exposure system escapes to the atmosphere by conduction, it is sufficient to circulate the temperature-controlled air.

[0011]

An apparatus for exposing in a vacuum using an EUV light source for printing a finer pattern has been proposed.

In an apparatus which performs exposure in a vacuum, heat conduction through air can be ignored. Therefore, the problem of fluctuation of the optical path of the interferometer, which has been a problem in the conventional example, does not occur. In addition, if the actuator and each member are configured so as not to contact with each other, the conduction of heat from the actuator via air can be ignored, and if the actuator coil is surrounded by a jacket and water-cooled, almost 100% of the heat generated from the coil is removed. As a result, the leakage of heat from the actuator to the outside is significantly reduced.

However, in an exposure apparatus in vacuum, the heat of exposure from the exposure system cannot escape to the surroundings because the surrounding area is vacuum. Furthermore, an electrostatic chuck is used in a vacuum because a vacuum chuck like the conventional example cannot be used. However, the electrostatic chuck has a characteristic of generating heat by itself, and the number of heat sources increases by one. When cooling water is caused to flow around the chuck to remove the exposure heat and the heat from the electrostatic chuck, the vibration from the cooling system is transmitted to the fine movement stage. Then, there is a drawback that the advantage of the vibration isolation of the 6-axis fine movement stage is lost and the positional accuracy of the fine movement stage is deteriorated.

The next conceivable method is the removal of heat using radiation, in which a radiation plate is provided near the chuck to control the temperature of the radiation plate and remove the electrostatic chuck and exposure heat. However, the radiation phenomenon occurs not only between the chuck and the radiation plate but also between all surrounding objects. Therefore, it is extremely difficult to control the chuck to a desired state even if the temperature of the radiation plate is controlled and only the amount of heat exchanged between the radiation plate and the chuck is controlled. That is, there is a problem that the temperature control by radiation is inaccurate.

An object of the present invention is to provide a highly accurate temperature adjusting means in a non-contact state in a vacuum and an exposure apparatus provided with the temperature adjusting means.

[0016]

[Means for Solving the Problems] The temperature of the radiation plate is set to a low temperature so that a sufficient amount of heat is always transferred from the chuck to the radiation plate, and the ambient temperature, that is, the transfer of heat to and from the surrounding object due to radiation is transferred. Regardless of the degree, the temperature of the chuck will decrease monotonically. Further, the chuck is provided with a heating body and a temperature measuring means so that the temperature is controlled by the amount of heat applied to the heating body.

EUV for printing fine patterns
An exposure apparatus that uses a light source to perform exposure in vacuum has been proposed. An electrostatic chuck is used to fix a workpiece such as a wafer in a vacuum, but the electrostatic chuck generates heat. If this is directly cooled, the vibration for cooling is transmitted to the wafer and the positional accuracy of the pattern deteriorates. Therefore, a radiation plate that is supported in non-contact with the chuck is provided, and the temperature of the radiation plate is set to a low temperature so that a sufficient amount of heat is always transferred from the chuck to the radiation plate. Temperature control should be performed according to the amount of heat applied to the heating element.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION <First Embodiment> An overall view is shown in FIG. Since it is a device used in vacuum, a vacuum chamber is provided, and the stage system is inside the vacuum chamber,
The inside of the vacuum chamber is maintained at a high vacuum. Since the stage configuration and the actuator configuration are the same as those of the conventional example, they are omitted. Only around the fine movement stage will be described with reference to FIG.

An electrostatic chuck for chucking the wafer is provided on the top plate of the fine movement stage, and the wafer is chucked by the electrostatic chuck. A hole is provided below the electrostatic chuck, and a radiation plate is provided so as to face the lower surface of the electrostatic chuck. Cooling means is provided below the radiating plate to remove the amount of heat received by the radiating plate and keep the temperature of the radiating plate low at all times.

The radiation plate and the cooling means therebelow are fixed to the coarse movement stage. The cooling means circulates the cooling medium as shown in the conventional example to remove heat by the heat capacity and flow rate of the medium, the phase change such as a heat pipe or a refrigeration system, and the adiabatic expansion of gas. A general means such as one that can be used.

Alternatively, a Peltier element may be interposed between the radiation plate and the cooling means to forcibly cool the radiation plate itself. In any case, in the cooling means, it is necessary to move heat to some medium to forcibly move the medium, and if the amount of heat removed increases, vibration tends to increase. But,
Since this cooling means is fixed to the coarse movement stage and is not in contact with the fine movement stage top plate, even if the cooling means vibrates, it is not transmitted to the fine movement stage top plate.

Below the electrostatic chuck, there are provided a plurality of heating elements composed of resistance elements connected to a power source (not shown) via lead wires (not shown) and a plurality of temperature detecting means, and the temperature of the electrostatic chuck is set to a desired temperature. The degree of heating of the electrostatic chuck can be adjusted as described above.

In the above structure, the exposure apparatus positions the wafer at a desired position or scans the wafer to expose the wafer. At this time, the heat generated in the actuator system is removed by the cooling jacket similar to the conventional example, but since the outside of the jacket is vacuum, almost 100% of the heat generated is recovered by the refrigerant in the jacket and hardly leaks outside. The problems are heat generation and exposure heat of the electrostatic chuck.

Although the temperature of the electrostatic chuck tends to rise by these, the temperature of the radiation plate provided at the hole is set to a low temperature so as to release a larger amount of heat than the heat generated by the electrostatic chuck and the exposure heat, so that the total temperature is reduced. As a result, heat is taken from the electrostatic chuck system. Furthermore, if the relative positions of the vacuum chamber wall and the surrounding projection system, main body system, etc. change, the transfer of heat by radiation to these peripheral objects also changes, but due to this fluctuation, The temperature of the radiant plate is set so that the heat is taken away. Therefore, if left untouched, the temperature of the electrostatic chuck will decrease monotonically.

The temperature of the radiation plate may be set so that the amount of heat received from the periphery of the electrostatic chuck + the amount of heat generated by the electrostatic chuck itself can be discharged. It does not need to be controlled with such high precision. Then, since the temperature detecting means provided on the lower surface of the chuck detects that the temperature is monotonically decreasing, the heating body may be controlled by a temperature control system as shown in FIG. 3 so as to keep the temperature constant.

In FIG. 3, a control calculation such as PID is performed on the temperature difference between the set temperature and the temperature detected by the temperature detecting means, and the result is used as a heat quantity command. Since the heat quantity ∝ is the square of the current of the resistance element, the heat quantity command is subjected to √ calculation to obtain the current command of the resistance element, and this is added to the current amplifier to control the current of the resistance element.

Such linearization is not always necessary, and if the heat fluctuation is small, the √ calculation may be omitted.

It is a local temperature control system which is closed only by the heating body on the lower surface of the chuck and the temperature detecting means irrespective of the radiation plate system. The control system of FIG. 3 may be independently applied to each of the plurality of pairs of temperature detecting means and the heating body as shown in FIG. 4, or a plurality of control systems may be provided in consideration of mutual interference as shown in FIG. The detection result of the temperature detection means may be subjected to matrix calculation for the purpose of non-interference and fed back to each control system.

The number of heating elements and the number of temperature detecting means do not have to be the same, and the combination of each number may be flexibly adapted. The amount of heat applied from the heating element is immediately returned to the temperature detecting means, which enables highly accurate temperature control.

As a result, highly accurate temperature control can be realized in a non-contact type exposure apparatus used in a vacuum.

<Second Embodiment> A second embodiment is shown in FIG.
In the first embodiment, the temperature control means is provided only near the lower surface of the chuck to control the temperature of only the chuck. However, the heat generated by the electrostatic chuck is also transmitted to the top plate and may deform the top plate. When the top plate is deformed, the relative relationship between the mirror and the wafer, which is a measurement reference, is changed, so that the positional accuracy of the wafer is deteriorated. Therefore, in the present embodiment, the temperature detecting means and the heating body are also provided on the lower surface of the top plate, and the lower surface of the top plate faces the radiation plate.

The structure, function and effect of the heating element, the temperature detecting means and the radiation plate are the same as those in the first embodiment.

The effect peculiar to the second embodiment is that not only the chuck but also the top plate is temperature-controlled, so that the deterioration of the wafer position accuracy due to the deformation of the top plate can be avoided.

<Third Embodiment> FIG. 7 shows a third embodiment.
The structure is the same as that of the first embodiment except the structure of the heating body. Only the heating element will be described.

The heating element on the lower surface of the top plate is composed of a simple conductor,
Basically, a coil is provided on the coarse movement stage side so as to face the conductor, and a high-frequency current is passed through the coil to flow an induction current through the conductor for high-frequency heating. A plurality of conductors are formed on the lower surface of the chuck. The conductor is preferably formed by forming a thin film by plating or vapor deposition. This is because the adhesion between the chuck and the conductor is improved and the thermal resistance at the boundary between the conductor and the chuck is reduced. The effect is basically the same as that of the first embodiment.

As an effect peculiar to the third embodiment, the wiring for the resistance element is unnecessary. As a result, the vibration transmission element to the fine movement stage is reduced, and the control accuracy of the fine movement stage is improved.

<Modifications> In the scanning type exposure apparatus, the mask, which is the original plate, is also scanned in synchronization with the wafer. For this reason, a mask stage is required, and the structure is the same as that of the wafer stage except that the coarse movement is uniaxial.

Therefore, the same structure as in the first to third embodiments can be applied to the cooling of the mask and the mask chuck.

The present invention can also be applied to other semiconductor manufacturing apparatuses that hold a wafer in vacuum and perform processing.

[0040]

As described above, according to the present invention, highly accurate temperature control can be realized without contact in a semiconductor exposure apparatus and a semiconductor manufacturing apparatus used in a vacuum.

[Brief description of drawings]

FIG. 1 is an overall view of a first embodiment.

FIG. 2 is a detailed view of the fine movement top plate according to the first embodiment.

FIG. 3 is a temperature control block diagram of the first embodiment.

FIG. 4 is a temperature control block diagram of the first embodiment.

FIG. 5 is a temperature control block diagram of the first embodiment.

FIG. 6 is a detailed view of the fine movement top plate according to the second embodiment.

FIG. 7 is a detailed view of a fine movement top plate according to a third embodiment.

FIG. 8 Overall view of conventional example

9A is a perspective view of a coarse movement stage H, FIG. 9B is a sectional view of a fine movement stage cooling system, and FIG. 9C is a sectional view of a coarse movement linear motor cooling system.

Claims (6)

[Claims] 1. A heat quantity removing means that is supported in a temperature control system of a semiconductor manufacturing apparatus used in a vacuum in the vicinity of a temperature control target in a non-contact manner with a temperature control target utilizing a radiation phenomenon, and directly connected to the temperature control target. A semiconductor manufacturing apparatus characterized by comprising a heating means and a temperature detecting means attached thereto. 2. The semiconductor manufacturing apparatus according to claim 1, wherein the heat quantity removing means comprises a radiation plate and a cooling means. 3. The semiconductor manufacturing apparatus according to claim 1, wherein the heating element is composed of a resistance element. 4. The semiconductor manufacturing apparatus according to claim 1, wherein the heating body is composed of a conductor directly attached to a temperature control target and a coil supported in a non-contact manner with the conductor. 5. The heating element control means according to any one of claims 1 to 4, wherein the heating element is controlled by a difference between a target temperature of a temperature control target and a temperature detected by the temperature detecting means. Semiconductor manufacturing equipment. 6. A semiconductor manufacturing apparatus having the temperature adjusting means according to claim 1.