JP2006339303A - Exposure apparatus and method, and manufacturing method of device - Google Patents

Exposure apparatus and method, and manufacturing method of device Download PDF

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JP2006339303A
JP2006339303A JP2005160465A JP2005160465A JP2006339303A JP 2006339303 A JP2006339303 A JP 2006339303A JP 2005160465 A JP2005160465 A JP 2005160465A JP 2005160465 A JP2005160465 A JP 2005160465A JP 2006339303 A JP2006339303 A JP 2006339303A
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temperature
substrate
exposure
wafer
substrate holding
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Yosuke Shirata
陽介 白田
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Nikon Corp
株式会社ニコン
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Abstract

PROBLEM TO BE SOLVED: To propose an exposure apparatus or the like capable of always placing a photosensitive substrate having substantially the same temperature as a substrate holder on the substrate holder even if the temperature of the substrate holder rises by repeatedly performing exposure processing.
In an exposure apparatus EX that performs exposure processing on a substrate W held on a substrate holding portion WH, a temperature calculation portion C1 that obtains the temperature of the substrate holding portion WH that changes with the exposure processing, and a substrate W on the substrate holding portion WH. Prior to mounting, a substrate temperature adjustment unit 50 that adjusts the temperature of the substrate W based on the temperature of the substrate holding unit WH obtained by the temperature calculation unit C1 is provided.
[Selection] Figure 1

Description

  The present invention relates to an exposure apparatus that exposes a photosensitive substrate, an exposure method, and a device manufacturing method.

In lithography processes for manufacturing semiconductor elements, etc., step-and-repeat reduction projection exposure apparatuses (so-called steppers) and step-and-scan scanning projection exposure apparatuses (so-called scanning steppers) Projection exposure apparatuses are the mainstream.
In such an exposure apparatus, as the capacity of a semiconductor memory increases and the speed and integration of a CPU processor increase, there is an increasing demand for finer patterns formed on a photosensitive substrate, and high exposure accuracy is required. Has been.
For this reason, in order to suppress an exposure failure due to deformation accompanying a temperature change of the photosensitive substrate, a technique has been proposed in which exposure is performed by placing the photosensitive substrate on a substrate stage after adjusting the temperature to a predetermined temperature.
Japanese Patent Laid-Open No. 10-55945

  By the way, in order to avoid exposure failure due to deformation accompanying a temperature change of the photosensitive substrate, it is sufficient that the temperature of the substrate holder on which the photosensitive substrate is placed is equal to the temperature of the photosensitive substrate. If the temperatures of the substrate holder and the photosensitive substrate are equal, the photosensitive substrate is not thermally deformed, and no exposure failure occurs.

  The present invention has been made in view of the above-described circumstances. Even when the temperature of the substrate holder rises by repeatedly performing the exposure process, a photosensitive substrate having the same temperature as that of the substrate holder is always placed on the substrate holder. An object of the present invention is to propose an exposure apparatus and the like that can be used.

In the exposure apparatus, the exposure method, and the device manufacturing method according to the present invention, the following means are adopted in order to solve the above problems.
In a first aspect of the present invention, in an exposure apparatus (EX) that performs an exposure process on a substrate (W) held on a substrate holding part (WH), a temperature calculation part (C1) that obtains the temperature of the substrate holding part that changes with the exposure process And a substrate temperature adjusting unit (50) for adjusting the temperature of the substrate based on the temperature of the substrate holding unit obtained by the temperature calculating unit prior to placing the substrate on the substrate holding unit.
According to the present invention, even if the temperature of the substrate holding portion changes (rises) with the exposure process, the temperature is calculated by the temperature calculating portion, and the substrate is adjusted to the temperature calculated by the substrate temperature adjusting portion. Therefore, the temperature difference between the substrate and the substrate holder can be eliminated.

Further, when the temperature calculation unit (C1) includes a temperature detection unit that detects the temperature of the substrate holding unit (WH), the temperature detection unit can directly detect the temperature change of the substrate holding unit.
The temperature calculation unit (C1) calculates the temperature of the substrate holding unit (WH) based on the exposure energy of the exposure light (EL) irradiated on the substrate (W) in the exposure process. The temperature change of the substrate holder can be obtained without using an apparatus.
In addition, during the exposure process of one substrate (W1), the temperature calculation unit (C1) performs the exposure process on another substrate (W2) that is processed after the one substrate (WH). In the case where the substrate holding unit adjusts the temperature of another substrate to be processed later to the temperature estimated by the estimation unit, the plurality of substrates are continuously exposed. Even in this case, it is possible to prevent a temperature difference from occurring when each substrate is placed on the substrate holder.
The temperature calculation unit (C1) includes an initial temperature calculation unit (C1) that calculates an initial temperature before the exposure processing of the substrate holding unit (WH) is started, and the initial temperature calculation unit is placed on the substrate holding unit. In the case of obtaining the initial temperature based on the thermal deformation of the substrate (W0), the initial temperature of the substrate holding unit can be obtained indirectly from the thermal deformation of the substrate, whereby the initial temperature between the substrate and the substrate holding unit can be obtained. Temperature error can be eliminated.
Further, in the case where the initial temperature calculating means (C1) calculates the initial temperature based on the amount of thermal deformation determined by measuring the arrangement of shot regions formed on the substrate (W0), the temperature of the substrate holding unit is determined. The initial temperature can be determined without direct measurement.

A second invention is an exposure method for performing an exposure process on a substrate (W) held on a substrate holding portion (WH), and the substrate at the time of placing the substrate before placing the substrate on the substrate holding portion. A stage for estimating the temperature of the holding part, a temperature control stage for adjusting the temperature of the substrate to the estimated temperature, and a placing stage for placing the temperature-controlled board on the substrate holding part are provided.
According to this invention, even if the temperature of the substrate holder changes with the exposure process, the temperature of the substrate holder is estimated and the temperature of the substrate is adjusted to that temperature, so the substrate is placed on the substrate holder. The temperature difference at the time can be eliminated.

  Further, in the estimation step of estimating the temperature of the substrate holding portion (WH) based on the exposure energy of the exposure light (EL) irradiated to the substrate (W) by the exposure process, the estimation stage uses the energy given to the substrate. The temperature change of the substrate holder can be estimated easily and with high accuracy.

According to a third invention, in the device manufacturing method including the lithography process, the exposure apparatus (EX) of the first invention is used in the lithography process. Further, the exposure method of the second invention is used.
According to this invention, since the thermal deformation of the substrate when the substrate is placed on the substrate holding part is suppressed, a device having a fine pattern can be manufactured.

  In addition, in order to explain each said invention clearly, it demonstrated corresponding to the code | symbol of drawing showing one Example, but it cannot be overemphasized that this invention is not limited to an Example.

According to the present invention, the following effects can be obtained.
According to the present invention, since the temperature difference between the substrate and the substrate holder can be eliminated, thermal deformation of the substrate when the substrate is placed on the substrate holder can be suppressed.
In addition, since a device having a fine pattern can be manufactured, a high-performance device can be provided.

Embodiments of an exposure apparatus, an exposure method, and a device manufacturing method according to the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic block diagram that shows an exposure apparatus EX of the present invention.
The exposure apparatus EX transfers the pattern PA formed on the reticle R to each shot area on the wafer W via the projection optical system PL while moving the reticle R and the wafer W synchronously in the one-dimensional direction. A scanning type exposure apparatus, that is, a so-called scanning stepper.
In the following description, the direction that coincides with the optical axis AX of the projection optical system PL is the Z-axis direction, and the synchronous movement direction (scanning direction) between the reticle R and the wafer W in the plane perpendicular to the Z-axis direction is the X-axis. The direction perpendicular to the direction, the Z-axis direction, and the Y-axis direction (non-scanning direction) is defined as the Y-axis direction. Further, the rotation (inclination) directions around the X axis, Y axis, and Z axis are the θX, θY, and θZ directions, respectively.

The exposure apparatus EX includes an illumination optical system IL that illuminates the reticle R with exposure light EL, a reticle stage RST that can move while holding the reticle R, and projection optics that projects the exposure light EL emitted from the reticle R onto the wafer W. The system PL, a wafer stage WST that can be moved while holding the wafer W via the wafer holder WH, a control device CONT that comprehensively controls the exposure apparatus EX, and the like are provided.
The exposure apparatus EX is an immersion exposure apparatus to which an immersion method is applied in order to improve the resolution by substantially shortening the exposure wavelength and substantially increase the depth of focus. And a liquid recovery device 44 for recovering the liquid on the wafer W. In the present embodiment, pure water (hereinafter simply referred to as water L) is used as the liquid.
Further, exposure apparatus EX includes a wafer temperature adjustment device 50 that adjusts the temperature of wafer W to substantially the same temperature as that of wafer holder WH prior to placing wafer W on wafer holder WH on wafer stage WST.

The illumination optical system IL illuminates the reticle R supported by the reticle stage RST with the exposure light EL, and is an optical integrator or optical integrator that equalizes the illuminance of the exposure light EL emitted from the exposure light source. A condenser lens that collects the exposure light EL, a relay lens system, a variable field stop for setting the illumination area on the reticle R by the exposure light EL in a slit shape, and the like (all not shown).
The predetermined illumination area on the reticle R is illuminated with the exposure light EL having a uniform illuminance distribution by the illumination optical system IL.

  Examples of the exposure light EL emitted from the exposure light source include far ultraviolet light (g-line, h-line, i-line), KrF excimer laser light (wavelength 248 nm), etc. Vacuum ultraviolet light (VUV light) such as DUV light) or ArF excimer laser light (wavelength 193 nm) is used. These are permeable to water L.

The reticle stage RST supports the reticle R, performs two-dimensional movement in the plane perpendicular to the optical axis AX of the projection optical system PL, that is, the XY plane, and minute rotation in the θZ direction. A reticle fine movement stage (not shown) to be held, a reticle coarse movement stage (not shown) that moves together with the reticle fine movement stage with a predetermined stroke in the Y-axis direction that is the scanning direction, and a reticle stage such as a linear motor that moves these reticle fine movement stages. A drive device RSTD is provided. Note that the reticle R is vacuum-sucked (or electrostatically-sucked) by a reticle suction mechanism provided around a rectangular opening formed in the fine movement stage.
A movable mirror 12 is provided on the reticle stage RST. The movable mirror 12 is a mirror for the laser interferometer 14 for measuring the position of the reticle stage RST. A laser interferometer 14 is provided at a position facing the movable mirror 12. Thus, the position of the reticle R on the reticle stage RST in the two-dimensional direction (XY direction) and the rotation angle in the θZ direction (including rotation angles in the θX and θY directions in some cases) are measured in real time by the laser interferometer 14. The measurement result is output to the control device CONT. Then, the control device CONT drives the reticle stage driving device RSTD based on the measurement result of the laser interferometer 14 to control the position of the reticle R supported by the reticle stage RST.

The projection optical system PL projects and exposes the pattern PA of the reticle R onto the wafer W at a predetermined projection magnification β, and includes a plurality of optical elements including an optical element 22 provided at the tip (lower end) portion on the wafer W side. These optical elements are supported by a lens barrel PK.
The projection optical system PL is a reduction system having a projection magnification β of, for example, 1/4, 1/5, or 1/8. Note that the projection optical system PL may be either an equal magnification system or an enlargement system.
The optical element 22 arranged at the lower end of the projection optical system PL is formed of meteorite. Since the meteorite has a high affinity with the water L, the water L can be brought into close contact with almost the entire liquid contact surface (lower surface) of the optical element 22. That is, since the water L having high affinity with the liquid contact surface of the optical element 22 is supplied, the adhesion between the liquid contact surface of the optical element 22 and the water L is high, and the optical element 22 and the wafer W Can be reliably filled with water L. The optical element 22 may be quartz having a high affinity with water. Further, the liquid contact surface of the optical element 22 may be subjected to a hydrophilization (lyophilic treatment) to further increase the affinity with the water L.

Wafer stage WST performs two-dimensional movement in the XY plane and fine rotation in the θZ direction while supporting wafer W. Wafer holder WH for holding wafer W and wafer holder WH in the Z-axis direction, θX direction, Further, the Z table 31 for performing leveling and focusing of the wafer W by fine driving in the three degrees of freedom direction in the θY direction and the Z table 31 are continuously moved in the Y axis direction and stepped in the X axis direction. A wafer stage 33 that supports the slidable motion in the XY plane, a wafer stage driving device WSTD such as a linear motor that moves the XY table 32, and the like.
Then, by moving the Z table 31, the position (focus position) of the wafer W held on the Z table 31 in the Z-axis direction and the positions in the θX and θY directions are controlled. Further, by moving the XY table 32, the position of the wafer W in the XY direction (position in a direction substantially parallel to the image plane of the projection optical system PL) is controlled. That is, the Z table 31 controls the focus position and tilt angle of the wafer W to align the surface of the wafer W with the image plane of the projection optical system PL by the autofocus method and the autoleveling method, and the XY table 32 is the wafer W. Is positioned in the X-axis direction and the Y-axis direction. Note that the Z table 31 and the XY table 32 may be provided integrally.

  A movable mirror 35 is provided on the Z table 31 of the wafer stage WST. A laser interferometer 36 is provided at a position facing the movable mirror 35. Accordingly, the position and rotation angle of wafer W on wafer stage WST in the two-dimensional direction are measured in real time by laser interferometer 36, and the measurement result is output to control unit CONT. Then, the control device CONT drives the wafer stage WST via the wafer stage drive device WSTD based on the measurement result of the laser interferometer 36, so that the X axis and the Y axis of the wafer W supported on the wafer stage WST. The direction, position in the θZ direction, speed, and the like are controlled.

  The wafer holder WH is formed in a shape corresponding to the wafer W, and is connected to an air supply / exhaust device (not shown) in order to suck and hold the wafer W placed on the wafer holder WH. When the wafer W is placed on the wafer holder WH, the lower surface of the wafer W is sucked and held by operating the air supply / exhaust device. The wafer holder WH is made of a ceramic or glass material because severe requirements are imposed on mechanical and thermal stability.

The control device CONT controls the exposure apparatus EX in an integrated manner, and stores various information in addition to a calculation unit C1 (temperature calculation unit, temperature estimation unit, initial temperature calculation unit) that performs various calculations and controls. The unit C2 and the input / output unit C3 are provided.
Then, for example, an exposure operation for controlling the positions of the reticle R and the wafer W based on the detection results of the laser interferometers 14 and 36 and transferring an image of the pattern PA formed on the reticle R to a shot area on the wafer W. Repeat.
The control device CONT controls the liquid supply device 42 and the liquid recovery device 44 and the wafer temperature adjustment device 50.

The liquid supply device 42 and the liquid recovery device 44 apply liquid to a part of the wafer W including the projection area of the projection optical system PL by the water L while at least transferring the pattern PA image of the reticle R onto the wafer W. The immersion area AR is formed, and is arranged in each of four directions around the lower end of the projection optical system PL.
Specifically, the liquid supply device 42 fills the water L between the optical element 22 at the tip of the projection optical system PL and the surface of the wafer W, and the water L between the projection optical system PL and the wafer W is filled. The image of the pattern PA of the reticle R is projected onto the wafer W via the projection optical system PL, and the wafer W is exposed. At the same time, by collecting the water L in the liquid immersion area AR by the liquid recovery device 44, the water L in the liquid immersion area AR is always circulated, and the contamination of the water L is strictly prevented and the temperature management is also performed. Is called. Of the members constituting the liquid supply device 42 and the liquid recovery device 44, at least the member through which the water L circulates is formed of a synthetic resin such as polytetrafluoroethylene. Thereby, it can suppress that an impurity is contained in the water L. FIG.
The liquid supply device 42 and the liquid recovery device 44 are connected to a pure water production device that produces pure water and a temperature control device (both not shown) for managing the pure water at a predetermined temperature. Note that at least one of the pure water production apparatus and the temperature control apparatus or a part of each apparatus may be arranged below the floor where the exposure apparatus EX is installed.
Then, the liquid supply amount and the liquid recovery amount per unit time on the wafer W by the liquid supply device 42 and the liquid recovery device 44 are controlled by the control device CONT.

  Prior to placing the wafer W on the wafer holder WH, the wafer temperature adjusting device 50 is in direct contact with the wafer W to perform heat exchange, thereby adjusting the temperature of the wafer W to substantially the same temperature as the wafer holder WH. The apparatus is disposed on a wafer carry-in path in the vicinity of wafer stage WST.

2A and 2B are schematic configuration diagrams showing the wafer temperature control device 50. FIG. 2A is a plan view and FIG. 2B is a cross-sectional view.
The wafer temperature adjustment device 50 includes a temperature adjustment plate 51 on which the wafer W is placed, a temperature adjustment unit 56 that heats or cools the temperature adjustment plate 51 to a predetermined temperature, and an air supply / exhaust device for holding the wafer W by suction. 54. The wafer temperature adjustment device 50 adjusts the temperature of the temperature adjustment plate 51 by the temperature adjustment unit 56, and heats or cools the wafer W placed on the temperature adjustment plate 51 to substantially the same temperature as the temperature of the wafer holder WH. It is supposed to adjust the temperature.
The temperature adjustment unit 56 is provided inside the temperature adjustment plate 51. As the temperature control unit 56, those using a medium such as a liquid and those using a thermoelectric element such as a Peltier element are suitable and controlled by the control device CONT.

A plurality of recesses 52 are formed on the upper surface of the temperature control plate 51. A suction hole 53 is formed at the center of the recess 52, and a flow path 55 is provided inside the temperature control plate 51 from the suction hole 53 to the air supply / exhaust device 54.
The air supply / exhaust device 54 sucks the gas in the recess 52 through the flow path 55, so that the wafer W is adsorbed and held on the temperature control plate 51. On the other hand, the suction / holding of the temperature control plate 51 and the wafer W is released by supplying (blowing) gas from the air supply / exhaust device 54.

The temperature control plate 51 having the above configuration is desirably formed of a material that is easy to process and has high thermal conductivity and does not contaminate the wafer W with metal. For example, silicon carbide can be used. Or not only a single material but the member which sprayed ceramics on the surface of the base made from aluminum can also be used.
The temperature of the temperature adjustment plate 51 is measured by a temperature sensor 57 provided in the temperature adjustment unit 56 of the wafer temperature adjustment device 50.

Next, exposure processing in the exposure apparatus EX, particularly control of the wafer temperature adjustment apparatus 50 will be described.
First, when a plurality of wafers W (W1, W2,...) Are subjected to exposure processing, the temperature of the wafer holder WH on the Z table 31 is obtained prior to starting the exposure processing (for example, at the lot head).
As a method of accurately measuring the temperature of the wafer holder WH, the reference wafer W0 is placed on the wafer holder WH, the thermal deformation of the reference wafer W0 is measured, and the control unit CONT (calculation unit C1) is based on the measurement result. ) Is used to calculate the temperature of the wafer holder WH.
Specifically, the reference wafer W0 is placed on the temperature adjustment plate 51 of the wafer temperature adjustment device 50 by a wafer loader (not shown), and is sucked and held on the temperature adjustment plate 51 by the air supply / exhaust device 54. The reference wafer W0 placed on the temperature adjustment plate 51 is adjusted to the same temperature as the set temperature (for example, 23 ° C.) of a chamber (not shown) in which the exposure apparatus EX is accommodated after a predetermined time has elapsed. Is done.
Here, the temperature of the reference wafer W0 is adjusted to substantially the same temperature as the set temperature of the chamber because the temperature of the wafer holder WH is expected to be substantially the same as the temperature around the wafer holder WH. . That is, since the temperature around the wafer holder WH is set and maintained with high accuracy by the chamber, the temperature of the wafer holder WH itself is considered to be substantially the same as the temperature in the chamber. is there.

When the temperature adjustment process for the reference wafer W0 is completed, the reference wafer W0 is moved onto the wafer holder WH by the wafer loader.
If there is no temperature difference between the reference wafer W0 and the wafer holder WH, the reference wafer W0 is sucked and held on the wafer holder WH without being thermally deformed. However, in practice, the temperature of the wafer holder WH is often not substantially the same as the temperature around the wafer holder WH. For this reason, a minute temperature difference is generated between the reference wafer W0 and the wafer holder WH.
Thus, the reference wafer W0 on the wafer holder WH is sucked and held in a state where minute thermal deformation has occurred.

Next, the thermal deformation of the reference wafer W0 is measured by performing alignment measurement on the reference wafer W0 using an alignment sensor (not shown). As an alignment method, for example, an EGA (enhanced global alignment) method disclosed in Japanese Patent Application Laid-Open No. 61-44429 can be employed.
Specifically, a predetermined number (for example, eight) of sample shot areas are selected from a plurality of shot areas (marks are formed corresponding to the respective shot areas) formed on the reference wafer W0, and this sample is selected. A mark corresponding to the shot area is detected by an alignment sensor, and its coordinate position is obtained. Based on the result, position information of all of the plurality of shot areas on the reference wafer W0 is obtained by calculation.
On the other hand, since the ideal coordinate position (design value, etc.) of each shot area is known, the deformation amount of each shot area on the reference wafer W0 can be obtained by comparing with the result of the alignment measurement.
Further, since the thermal expansion coefficient of the reference wafer W0 is known, the temperature difference between the reference wafer W0 and the wafer holder WH is obtained from the obtained deformation amount of each shot area. And the exact temperature of the wafer holder WH is calculated | required from the calculated | required temperature difference and the temperature of the reference | standard wafer W0 (temperature control temperature of the temperature control board 51).
As described above, by placing the reference wafer W0 on the wafer holder WH on the Z table 31 and measuring the array of a plurality of shot areas formed on the reference wafer W0, that is, performing alignment measurement, the wafer holder WH Accurate temperature is required.
Note that the reference wafer W0 subjected to the alignment measurement is unloaded from the wafer holder WH without being subjected to an exposure process.

After the accurate temperature of the wafer holder WH is obtained, the wafer W1 to be exposed is adjusted to a temperature substantially the same as the temperature of the wafer holder WH (for example, a temperature difference of ± 0.01 ° C. or less) by the wafer temperature adjustment device 50. .
Specifically, first, the wafer W1 is loaded onto the temperature adjustment plate 51 of the wafer temperature adjustment device 50 by the wafer loader and held by suction. At this time, the temperature of the temperature control plate 51 is adjusted to substantially the same temperature as the temperature of the wafer holder WH obtained in the above-described process. For this reason, the temperature of the wafer W1 is adjusted to substantially the same temperature as the temperature of the wafer holder WH.
Then, when the temperature adjustment processing of the wafer W1 is completed, the wafer W1 is loaded onto the wafer holder WH by the wafer loader and held by suction. At this time, there is almost no temperature difference between the wafer W1 and the wafer holder WH. Note that the temperature of the wafer W1 may change while the wafer W1 is loaded to the wafer holder WH. In this case, in order to set the temperature difference between the two at the time of placing the wafer W1 on the wafer holder WH to be ± 0.01 ° C. or less, an offset corresponding to the temperature change may be added to the target temperature of the wafer temperature adjusting device 50. .
In this way, the temperature of the wafer holder WH is calculated by the calculation unit C1, and the temperature of the wafer W1 is adjusted to be substantially the same as this temperature, so that the wafer W1 is attracted and held on the wafer holder WH without causing thermal deformation. Can do.

When the loading of the wafer W1 onto the wafer holder WH is completed, the liquid supply device 42 and the liquid recovery device 44 are operated to form the liquid immersion area AR on the wafer W.
Next, the reticle R supported by the reticle stage RST is illuminated with the exposure light EL by the illumination optical system IL, and the pattern image of the reticle R is projected onto the wafer W1 held on the wafer holder WH by the projection optical system PL and the water L. Project through. Here, since the temperature of the wafer W1 is controlled to be substantially the same as that of the wafer holder WH, there is no distortion (thermal deformation) on the surface of the wafer W1. Therefore, pattern superposition is performed with high accuracy.

By the way, when the exposure processing of the wafer W1 is started, the wafer holder WH is heated via the wafer W1 by the exposure energy of the exposure light EL irradiated to the wafer W1. That is, the temperature of the wafer holder WH gradually increases. Specifically, a temperature rise of about 0.03 ° C. occurs.
For this reason, if the wafer W2 to be exposed next is temperature-controlled to substantially the same temperature as the wafer W1 and then loaded onto the wafer holder WH, a temperature difference occurs between the wafer W2 and the wafer holder WH. The surface will be distorted.
Therefore, the temperature rise of the wafer holder WH accompanying the exposure processing of the wafer W1 is obtained, and the temperature of the temperature control plate 51 is controlled in accordance with the temperature change. That is, by adjusting the temperature of the temperature control plate 51 in accordance with the temperature of the wafer holder WH after the exposure processing of the wafer W1, no temperature difference is generated between the wafer W2 and the wafer holder WH.
As a specific method for obtaining the temperature rise of the wafer holder WH, in the present embodiment, the temperature rise of the wafer holder WH is controlled by the control device CONT (calculation unit C1) based on the exposure energy of the exposure light EL applied to the wafer W1. The calculation method is used.
That is, the exposure energy of the exposure light EL applied to the wafer W1 is mainly determined by the irradiation intensity, the irradiation area (blind setting), the reticle transmittance (including the pattern presence rate), the projection lens transmittance, and the irradiation time. The irradiation intensity of the exposure light EL can be measured by an exposure amount sensor (not shown) provided in the illumination optical system IL, and the projection lens transmittance is an irradiation amount (not shown) provided on the Z table. It can be measured by a sensor. Further, the reticle transmittance is known, and the irradiation area and exposure time are defined in the exposure program (exposure conditions).
Therefore, the exposure energy applied to the wafer holder WH per shot area is calculated by the calculation unit C1 from these exposure conditions and the like. Further, since the number of shots on the wafer W1 and the exposure time are defined in the exposure program, the temperature rise of the wafer holder WH during the exposure processing of the wafer W1 is calculated.

Thus, the temperature rise of the wafer holder WH accompanying the exposure processing of the wafer W1 can be obtained by the calculation unit C1. Therefore, it is possible to control the temperature of the temperature adjustment plate 51 in accordance with the temperature rise and to adjust the temperature of the wafer W2 by the temperature adjustment plate 51.
When the exposure processing for the wafer W1 is completed, the wafer W1 is unloaded from the wafer holder WH. Subsequently, the wafer W2 placed on the temperature control plate 51 is loaded onto the wafer holder WH. Also here, since the temperature of the wafer W2 is adjusted to the same temperature as the temperature of the wafer holder WH rises, no distortion (thermal deformation) occurs on the surface of the wafer W2. Therefore, pattern superposition is performed with high accuracy.

By repeatedly performing the above operations, the exposure processing of the plurality of wafers W1 to Wn is performed with high accuracy.
Thus, according to the present invention, even if the temperature of the wafer holder WH changes with the exposure processing, it is possible to prevent a temperature difference from occurring between the wafer W and the wafer holder WH. Thereby, when the wafer W is loaded on the wafer holder WH, the occurrence of distortion on the wafer W can be suppressed. Therefore, a fine pattern can be exposed on the wafer W with high accuracy.
In addition, since the calculation unit C1 obtains a temperature rise associated with the exposure processing of the wafer holder WH based on the exposure energy of the exposure light applied to the wafer W, a temperature sensor (including wiring) for measuring the temperature of the wafer holder WH is obtained. ), And the weight of wafer stage WST can be reduced.
Further, since the calculation unit C1 obtains the initial temperature of the wafer holder WH before starting the exposure processing based on the thermal deformation of the reference wafer W0, the initial temperature error between the wafer W and the wafer holder WH can be eliminated. In particular, since the thermal deformation of the reference wafer W0 can be obtained using the measurement result of the alignment apparatus of the exposure apparatus, an increase in apparatus cost can be suppressed.

Although the embodiment of the present invention has been described above, the operation procedure shown in the above-described embodiment, or the shapes and combinations of the constituent members are examples, and the design is made without departing from the gist of the present invention. Various changes can be made based on the requirements.
For example, the present invention includes the following modifications.

In the above-described embodiment, as a method for measuring the initial temperature of the wafer holder WH, the method for measuring the amount of thermal deformation of the reference wafer W0 placed on the wafer holder WH and calculating the temperature difference from the wafer holder WH is described. Not limited to this.
For example, the deformation amount (or variation component of shot arrangement) of the reference wafer W0 is sequentially measured while changing the temperature of the temperature adjustment plate 51, and the temperature of the temperature adjustment plate 51 that minimizes the deformation amount (the variation component). Can be the initial temperature.
Further, for example, a temperature sensor (temperature detection unit) may be provided in the wafer holder WH. In this case, the temperature rise of the wafer holder WH can also be measured by this temperature sensor.
Further, the initial temperature of the wafer holder WH may be measured using a wafer with a temperature sensor instead of the reference wafer W0.

  In the embodiment described above, the temperature of the wafer W is controlled so as to coincide with the temperature of the wafer holder WH. In accordance with this, the temperature of the liquid (pure water) supplied from the liquid supply device onto the wafer W is adjusted. You may control so that it may correspond with the temperature of the wafer holder WH and the wafer W. FIG. In this case, when it is predicted that the imaging characteristics of the projection optical system PK will change according to the temperature rise of the liquid, the optical elements included in the projection optical system PL according to the temperature of the supplied liquid The image forming characteristics may be corrected by adjusting the position of a part of the image. For correcting the imaging characteristics, for example, a technique disclosed in Japanese Patent Laid-Open No. 5-251299 can be used.

  In the above-described embodiment, the case of the immersion exposure apparatus that forms a predetermined pattern on the substrate via the liquid supplied between the projection optical system and the substrate (wafer) has been described. The present invention can also be applied to a dry type exposure apparatus.

  In the above embodiment, the case where a KrF excimer laser, an ArF excimer laser, or the like is used as a light source has been described. However, the present invention is not limited to this, and an F2 laser or Ar2 laser may be used as a light source, or a metal vapor laser or a YAG laser is used. These harmonics may be used as exposure illumination light. Alternatively, infrared or visible single wavelength laser light oscillated from a DFB semiconductor laser or fiber laser is amplified by a fiber amplifier doped with, for example, erbium (Er) (or both erbium and ytterbium (Yb)). Then, a harmonic wave converted to ultraviolet light using a nonlinear optical crystal may be used as illumination light for exposure.

  In the above embodiment, the step-and-scan type exposure apparatus has been described as an example. However, the present invention can also be applied to a step-and-repeat type exposure apparatus. Further, the present invention is not limited to an exposure apparatus used for manufacturing a semiconductor element, but also used for manufacturing a display including a liquid crystal display element (LCD) and the like, and an exposure apparatus for transferring a device pattern onto a glass plate, and a thin film magnetic head. The present invention can also be applied to an exposure apparatus that is used for manufacturing and transfers a device pattern onto a ceramic wafer, and an exposure apparatus that is used to manufacture an image sensor such as a CCD.

Further, the projection optical system PL may be any of a refraction system, a catadioptric system, and a reflection system, and may be any of a reduction system, an equal magnification system, and an enlargement system.
Furthermore, in an exposure apparatus that transfers a circuit pattern onto a glass substrate or a silicon wafer in order to manufacture a reticle or mask used in an optical exposure apparatus, EUV exposure apparatus, X-ray exposure apparatus, electron beam exposure apparatus, or the like. The present invention can also be applied. Here, in an exposure apparatus using DUV (far ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used. As a reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, Magnesium fluoride or quartz is used. Further, in a proximity type X-ray exposure apparatus or an electron beam exposure apparatus, a transmission mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate.
Such an exposure apparatus is disclosed in WO99 / 34255, WO99 / 50712, WO99 / 66370, JP-A-11-194479, JP-A2000-12453, JP-A-2000-29202, and the like. .

The present invention can also be applied to a twin stage type exposure apparatus. The structure and exposure operation of a twin stage type exposure apparatus are disclosed in, for example, Japanese Patent Laid-Open Nos. 10-163099, 10-214783, 2000-505958, or US Pat. No. 6,208,407.
In addition, as disclosed in JP-A-11-135400, the present invention includes an exposure stage that can move while holding a substrate to be processed such as a wafer, and a measurement stage that includes various measurement members and sensors. The present invention can also be applied to other exposure apparatuses.

  An exposure apparatus to which the present invention is applied is a light transmissive mask in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light transmissive substrate, or a light transmissive substrate. For example, a transmission pattern based on electronic data of a pattern to be exposed, such as disclosed in US Pat. No. 6,778,257, is not limited to the one using a light reflection type mask on which a reflection pattern is formed. Alternatively, it may be an exposure apparatus using an electronic mask that forms a reflection pattern or a light emission pattern.

As described in JP-A-8-330224 (corresponding to US Pat. No. 5,874,820), the reaction force generated by the movement of the reticle stage is not mechanically transmitted to the projection optical system using a frame member. You may escape to the floor (ground).
Further, the reaction force generated by the movement of the wafer stage is not transmitted to the projection optical system by using a frame member as described in JP-A-8-166475 (corresponding USP 5,528, 126). You may mechanically escape to the floor (ground).

Next, an embodiment of a manufacturing method of a micro device using the exposure apparatus and the exposure method according to the embodiment of the present invention in the lithography process will be described.
FIG. 3 is a flowchart showing a manufacturing example of a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.).
First, in step S10 (design step), function / performance design (for example, circuit design of a semiconductor device) of a micro device is performed, and pattern design for realizing the function is performed. Subsequently, in step S11 (mask manufacturing step), a mask (reticle) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S12 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

  Next, in step S13 (wafer processing step), using the mask and wafer prepared in steps S10 to S12, an actual circuit or the like is formed on the wafer by lithography or the like, as will be described later. Next, in step S14 (device assembly step), device assembly is performed using the wafer processed in step S13. This step S14 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary. Finally, in step S15 (inspection step), inspections such as an operation confirmation test and a durability test of the microdevice manufactured in step S14 are performed. After these steps, the microdevice is completed and shipped.

FIG. 4 is a diagram illustrating an example of a detailed process of step S13 in the case of a semiconductor device.
In step S21 (oxidation step), the surface of the wafer is oxidized. In step S22 (CVD step), an insulating film is formed on the wafer surface. In step S23 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step S24 (ion implantation step), ions are implanted into the wafer. Each of the above steps S21 to S24 constitutes a pre-processing process at each stage of the wafer processing, and is selected and executed according to a necessary process at each stage.

  At each stage of the wafer process, when the above pre-process is completed, the post-process is executed as follows. In this post-processing process, first, in step S25 (resist formation step), a photosensitive agent is applied to the wafer. Subsequently, in step S26 (exposure step), the circuit pattern of the mask is transferred to the wafer by the lithography system (exposure apparatus) and the exposure method described above. Next, in step S27 (development step), the exposed wafer is developed, and in step S28 (etching step), the exposed members other than the portion where the resist remains are removed by etching. In step S29 (resist removal step), the resist that has become unnecessary after the etching is removed. By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the wafer.

  Further, the present invention can be applied not only to microdevices such as semiconductor elements but also to the production of reticles or masks used in optical exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, and the like.

It is a schematic block diagram which shows the exposure apparatus EX which concerns on embodiment of this invention. It is a schematic block diagram which shows the wafer temperature control apparatus 50 which concerns on this embodiment. It is a flowchart figure which shows an example of the manufacturing process of a microdevice. It is a figure which shows an example of the detailed process of step S13 in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 50 ... Wafer temperature control apparatus C1 ... Operation part WH ... Wafer holder W (W1, W2) ... Wafer W0 ... Reference wafer EX ... Exposure apparatus EL ... Exposure light


Claims (10)

  1. In an exposure apparatus that performs exposure processing on a substrate held by a substrate holding unit,
    A temperature calculation unit for obtaining a temperature of the substrate holding unit that changes with exposure processing;
    Prior to placing the substrate on the substrate holding unit, a substrate temperature adjusting unit for adjusting the temperature of the substrate based on the temperature of the substrate holding unit obtained by the temperature calculating unit;
    An exposure apparatus comprising:
  2.   The exposure apparatus according to claim 1, wherein the temperature calculation unit includes a temperature detection unit that detects a temperature of the substrate holding unit.
  3.   The exposure apparatus according to claim 1, wherein the temperature calculation unit obtains the temperature of the substrate holding unit based on exposure energy of exposure light applied to the substrate in an exposure process.
  4. The temperature calculation unit includes an estimation unit that estimates a temperature of the substrate holding unit at a time when another substrate processed after the one substrate is exposed during the exposure processing of the one substrate,
    The exposure apparatus according to claim 2, wherein the substrate holding unit adjusts the temperature of another substrate to be processed later to the temperature estimated by the estimation unit.
  5. The temperature calculation unit includes an initial temperature calculation unit that calculates an initial temperature of the substrate holding unit before the exposure process starts,
    The said initial temperature calculation means calculates | requires the said initial temperature based on the thermal deformation of the said board | substrate mounted in the said board | substrate holding part, The Claim 1 characterized by the above-mentioned. Exposure equipment.
  6.   6. The exposure apparatus according to claim 5, wherein the initial temperature calculation means calculates the initial temperature based on a thermal deformation amount obtained by measuring an array of shot areas formed on the substrate.
  7. An exposure method for performing an exposure process on a substrate held by a substrate holding unit,
    Estimating the temperature of the substrate holding portion at the time of placing the substrate before placing the substrate on the substrate holding portion;
    Adjusting the temperature of the substrate to an estimated temperature; and
    Placing the temperature-adjusted substrate on the substrate holding unit; and
    An exposure method comprising:
  8.   The exposure method according to claim 7, wherein the estimating step estimates the temperature of the substrate holding unit based on exposure energy of exposure light applied to the substrate by exposure processing.
  9.   A device manufacturing method including a lithography process, wherein the exposure apparatus according to any one of claims 1 to 6 is used in the lithography process.
  10. A device manufacturing method including a lithography process, wherein the exposure method according to claim 7 or 8 is used in the lithography process.


JP2005160465A 2005-05-31 2005-05-31 Exposure apparatus and method, and manufacturing method of device Pending JP2006339303A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013201463A (en) * 2007-07-31 2013-10-03 Nikon Corp Adjustment method of exposure apparatus, exposure apparatus, and device manufacturing method

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6144429A (en) * 1984-08-09 1986-03-04 Nippon Kogaku Kk <Nikon> Alignment method
JPH1050588A (en) * 1996-08-01 1998-02-20 Nikon Corp Exposing device
JPH1055945A (en) * 1996-08-08 1998-02-24 Nikon Corp Exposing method and device
JP2001274078A (en) * 2000-03-28 2001-10-05 Canon Inc Temperature control apparatus, device manufacturing apparatus and device manufacturing method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6144429A (en) * 1984-08-09 1986-03-04 Nippon Kogaku Kk <Nikon> Alignment method
JPH1050588A (en) * 1996-08-01 1998-02-20 Nikon Corp Exposing device
JPH1055945A (en) * 1996-08-08 1998-02-24 Nikon Corp Exposing method and device
JP2001274078A (en) * 2000-03-28 2001-10-05 Canon Inc Temperature control apparatus, device manufacturing apparatus and device manufacturing method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013201463A (en) * 2007-07-31 2013-10-03 Nikon Corp Adjustment method of exposure apparatus, exposure apparatus, and device manufacturing method
US9025126B2 (en) 2007-07-31 2015-05-05 Nikon Corporation Exposure apparatus adjusting method, exposure apparatus, and device fabricating method

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