JP2003234275A - Exposure apparatus, exposure method, device manufacturing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure apparatus capable of normally measuring permeability changes of all optical systems including a projecting optical system and controlling total exposure more precisely in an exposure process, and an exposure method, a device manufacturing method and its device. <P>SOLUTION: The exposure apparatus includes a projecting optical system for projecting a pattern formed in a mask on a body to be processed, including a reflecting optical member for generating a divided beam by dividing an incident beam and a detecting portion for detecting the light quantity of the divided beam, and a control portion for controlling the light quantity projected on the body to be processed based on the detecting result of the detecting portion. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an exposure apparatus and method, and more particularly, it is used for manufacturing devices such as a single crystal substrate for a semiconductor wafer and a glass substrate for a liquid crystal display (LCD). Exposure apparatus and method,
The present invention relates to a device manufacturing method and a device manufactured from the object to be processed. INDUSTRIAL APPLICABILITY The present invention is suitable for, for example, an exposure method in which, in a photolithography process, a circuit pattern drawn on a mask or a reticle (the terms are used interchangeably in the present application) is subjected to projection exposure on an object to be processed.

[0002]

2. Description of the Related Art When a device is manufactured by using a photolithography technique, a projection exposure apparatus which projects a circuit pattern drawn on a mask onto a wafer or the like by a projection optical system and transfers the circuit pattern has been conventionally used. There is. The projection exposure apparatus generally has an illumination optical system that illuminates a mask and a projection optical system that is arranged between the mask and the object to be processed and projects the illuminated circuit pattern of the mask onto the object to be processed.

The projection exposure apparatus exposes the object to be processed using, for example, a step-and-repeat method or a step-and-scan method. The step-and-repeat exposure apparatus is also called a stepper, and uses an exposure method in which a wafer is stepwise moved for each batch exposure of a shot of a wafer to move the next shot to an exposure area. The step-and-scan type exposure apparatus is also called a scanner,
An exposure method is used in which the wafer is continuously scanned with respect to the mask to expose the mask pattern on the wafer, and after the exposure of one shot is completed, the wafer is step-moved to the exposure area of the next shot.

The minimum size (resolution) that can be transferred by the projection exposure apparatus is proportional to the wavelength of light used for exposure and inversely proportional to the numerical aperture of the projection optical system. Therefore, the shorter the wavelength, the better the resolution.

For this reason, recent light sources include ultra-high pressure mercury lamps (g line (wavelength: about 436 nm), i line (wavelength: about 365 n).
m)) to a short wavelength KrF excimer laser (wavelength about 248 nm) or ArF excimer laser (wavelength about 193 nm).
nm, and the F ₂ laser (wavelength about 15 nm
(7 nm) is also in practical use.

Further, in order to improve the transfer fidelity, it is also necessary to perform control (that is, exposure amount control) for exposing the photosensitive agent applied on a substrate such as a wafer with an appropriate exposure amount with high accuracy. Becomes

The exposure amount control method in the stepper measures the exposure amount during each shot exposure by a sensor provided inside the illumination optical system, and reaches the wafer from the sensor which is assumed to be the measurement result and a certain value in advance. The transmittance of the optical system (a part of the illumination optical system and the projection optical system) is multiplied to obtain the estimated exposure amount on the wafer, and the exposure amount for the next shot is adjusted based on the estimated exposure amount (for example, light source output or ND). Adjust with a filter, etc.).

On the other hand, in the exposure amount control method in the scanner, each shot is exposed with a plurality of pulses during scanning, and during this period, the light amount is constantly measured by a sensor inside the illumination optical system, and there is an integrated exposure amount within the shot. Output of the light source (for example, energy per pulse or oscillation frequency) so as to reach a predetermined value (that is, the optimum exposure amount determined by the resist)
Adjust. Also in this case, similarly to the scanner, the exposure amount on the wafer is estimated by multiplying the measurement result by the transmittance of the optical system from the sensor to the wafer which is assumed to be a certain value in advance.

FIG. 11 is a schematic block diagram of a conventional step-and-scan type exposure apparatus 1000. Wafer 140 for various illumination modes (such as annular illumination conditions)
The illuminance on the 0th surface is measured by the detector 1500, output calibration with the integrated exposure amount sensor 1210 in the illumination optical system 1200 is performed in advance, and the calibration result is stored. Further, in various illumination modes, the illuminance distribution in the exposure area is measured by moving the detector 1500 two-dimensionally, and the variable slit 1220 achieves and stores a shape such that the illuminance distribution is uniform during scanning exposure. Keep it.

Next, when an arbitrary illumination mode is designated and the exposure amount at that time is set, the wafer stage 1450
Scanning speed V (mm / sec), variable slit 1120
Width W (mm) in the scanning direction and laser oscillation frequency F
(Hz) is determined so as to satisfy the following equation.

[0011]

[Equation 1]

N is the number of exposure pulses, which is the number of pulses irradiated during scanning exposure when one point on the exposure surface is focused.
The minimum value of the number of pulses is determined from the sensitivity of the mask used, the pulse energy of the light source, and the like, and the number of pulses equal to or greater than the minimum value is required for exposure.

In actual exposure, it is necessary to keep the scanning speed V high in order to improve the throughput. Therefore, since the scanning direction width W (mm) of the variable slit 1220 is fixed for each illumination mode, the output (pulse energy and oscillation frequency F) of the light source 1100 and the dimming member are satisfied so as to satisfy the minimum condition of the pulse number n. The adjustment of 1230 is performed and the feedback control of the exposure amount is performed while constantly monitoring the integrated light amount sensor 1210. That is, the exposure amount control during exposure is always performed by the integrated light amount sensor 1210 in the illumination optical system 1200, but the calibration of the output value of the integrated light amount sensor 1210 and the illuminance of the actual exposure surface is performed separately from the exposure. There is.

[0014]

However, since the photon energy becomes high due to the shortening of the wavelength of the light source, it causes a photochemical reaction with the optical members (glass material or coating material) and substances in the atmosphere in the optical path, and the transmission of the optical system. The rate will change.

For example, from the data of basic research on quartz materials, there are both short-term absorption and long-term deterioration due to laser irradiation. Furthermore, it has been found that absorption is once reduced (restoration of transmittance) when irradiation is stopped, and returns to the absorption curve up to then (resumption of absorption) when irradiation is restarted. Therefore, also in the exposure apparatus, the degree of transmittance variation complicatedly varies depending on the exposure conditions (laser pulse energy, pulse number, illumination mode, reticle transmittance, exposure pause, etc.).

Therefore, in the conventional exposure apparatus 1000 as shown in FIG. 11, since the integrated exposure amount sensor 1210, which constantly monitors the light amount, is arranged in the illumination optical system 1200, the half mirror 1240 in the illumination system and thereafter. If the change in the transmittance of the optical system occurs, the exposure amount on the surface of the wafer 1400 cannot be accurately monitored, and the accuracy of the exposure amount control deteriorates.

Further, in order to improve the accuracy of the exposure amount control, the exposure is frequently stopped and the illuminance of the exposure surface is measured,
The output of the integrated exposure amount measuring sensor 1210 must be calibrated, which leads to a decrease in throughput.

Therefore, according to the present invention, the exposure apparatus and the exposure method are capable of constantly measuring the change in the transmittance of the entire optical system including the projection optical system even during the exposure process and controlling the integrated exposure amount more accurately. It is an exemplary object to provide a device manufacturing method and a device.

[0019]

In order to achieve the above object, an exposure apparatus according to one aspect of the present invention is a projection optical system for projecting a pattern formed on a mask onto an object to be processed. A projection optical system having a reflective optical member that generates a divided light beam by dividing the light beam, a detection unit that detects the light amount of the divided light beam, and the light amount that is projected on the object to be processed based on the detection result of the detection unit. And a control unit for controlling. According to such an exposure apparatus, since the light amount is detected in the projection optical system, the light amount at a position closer to the object to be processed can be detected, and the exposure amount can be controlled based on the detection result. The projection optical system is an optical system including at least a reflecting member, and the optical member is the reflecting member having a positive or negative refractive power of the projection optical system. As a result, the reflection member of the projection optical system can be used as an optical member, and installation of the optical member can be omitted. The optical member is a half mirror.

An exposure apparatus according to another aspect of the present invention is a cat for projecting a pattern formed on a mask onto an object to be processed.
A projection optical system, which is an adiooptic (catadioptric type) optical system, having a reflective optical member that generates a divided light beam by reflecting and transmitting an incident light beam, and a detection unit that detects the light amount of the divided light beam, And a control unit that controls the amount of light projected onto the object to be processed based on the detection result of the detection unit. This exposure apparatus also has the same operation as that of the above-described exposure apparatus.

An exposure apparatus as yet another aspect of the present invention is a projection optical system that projects a pattern formed on a mask onto an intermediate image plane and then re-projects it onto an object to be processed. And a projection optical system having a reflective optical member that generates a divided light beam by transmitting the light beam, and a detection unit that detects the light amount of the divided light beam, and the light amount that is projected on the object to be processed based on the detection result of the detection unit. And a control unit for controlling. This exposure apparatus also has the same operation as that of the above-described exposure apparatus. The optical member is provided between the optical member adjacent to the intermediate image surface and the intermediate image surface. The optical member is placed closer to the mask than the intermediate image plane, and is arranged obliquely with respect to the optical axis. The detection unit is arranged at a position optically conjugate with the position where the intermediate image is formed. This makes it possible to detect the amount of light at a position optically conjugate with the object to be processed, that is, at a position where an intermediate image is formed, by using the reflected light from the optical member.

In the above-described exposure apparatus, the optical member is arranged at the pupil position of the projection optical system. Thereby, the amount of light at the pupil position can be detected by using the transmitted light from the optical member. The divided luminous flux is reflected light reflected by the optical member or transmitted light transmitted through the optical member. The illumination optical system further includes an integrated light amount detecting means for detecting the integrated light amount at a position optically conjugate with the mask and the object to be processed. As a result, the change in the light amount of the projection optical system can be reflected in the detection result of the integrated light amount detecting means, and the exposure amount can be controlled with higher accuracy.

An exposure method according to still another aspect of the present invention uses a light flux reflected or transmitted through a mask arranged on an illuminated surface as exposure light, and the exposure light is processed through a projection optical system. An exposure method for projecting light onto the object to be processed by exposing the object to be processed, the step of setting the amount of light on the object to be processed for an arbitrary illumination mode, and a first detection step of detecting the amount of light in the projection optical system. And exposing so that the light quantity on the object to be processed becomes the light quantity set in the setting step based on the detection result of the first detection step. According to such an exposure method, since the light quantity at the projection optical system, for example, the substantially pupil position or the substantially intermediate image formation position is detected, it is possible to detect the light quantity at a position closer to the object to be processed, and based on the detection result. By controlling the exposure amount, highly accurate control becomes possible. A second detection step of detecting a light amount at a position conjugate with the surface to be illuminated and / or the object to be processed during exposure, a light amount detected in the second detection step, and the first detection step. The method further includes a step of calculating a change amount with respect to the detected light amount, and the light amount on the object to be processed is set in the setting step by reflecting the change amount in the detection result of the second detection step. It is exposed to light intensity. Thereby, for example, the exposure can be controlled with higher accuracy by reflecting the amount of light in the illumination that illuminates the mask.

An exposure method according to still another aspect of the present invention is an exposure method of exposing exposure light onto an object to be processed by projecting exposure light onto the object via a projection optical system. A step of setting the amount of light on the object to be processed, a step of storing a change in the amount of light on the surface of the object to be processed when performing exposure based on the amount of light set in the setting step; A step of detecting a light amount at a substantially pupil position or a substantially intermediate image forming position, and the setting step for setting the light amount on the object to be processed based on the change in the light amount detected in the detecting step and the stored change in the light amount. It is characterized in that the exposure is performed so as to obtain the light amount set in step. This exposure method also has the same operation as that of the above-described exposure method.

In the above-mentioned exposure method, the detection step is always performed during exposure. This enables real-time exposure amount control. The detection step is periodically performed at a predetermined timing. As a result, during scanning exposure,
It is not affected by the change in the light quantity due to the difference in mask pattern or the effect of time within a shot.

An exposure apparatus as still another aspect of the present invention has an exposure mode in which exposure is performed by the above-mentioned exposure method. This exposure apparatus also has the same operation as that of the above-described exposure method.

A projection optical system as yet another aspect of the present invention is a projection optical system for projecting a pattern on an object plane onto an image plane, and comprises a half mirror and a light beam extracted through the half mirror. And a detection unit that detects the amount of light. According to such a projection optical system, it is possible to configure a device capable of detecting the amount of light in the projection optical system.

A projection optical system as still another aspect of the present invention is a projection optical system which is composed of at least a reflecting member and projects a pattern on the object plane onto an image plane, wherein the reflecting member is a half mirror. , And has a detection unit that detects the amount of light flux extracted by the half mirror. This projection optical system also has the same operation as that of the projection optical system described above.

According to still another aspect of the present invention, a device manufacturing method includes a step of projecting and exposing the object to be processed using the above-described exposure apparatus, and a predetermined process for the object to be projected and exposed. And steps. The claims of the device manufacturing method having the same operation as the above-described operation of the exposure apparatus extend to the devices themselves which are intermediate and final products. In addition, such devices are LSI and V
It includes semiconductor chips such as LSIs, CCDs, LCDs, magnetic sensors, thin film magnetic heads, and the like.

Further objects or other features of the present invention are:
It will be apparent from the preferred embodiments described below with reference to the accompanying drawings.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION An exposure apparatus according to one aspect of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to these examples, and each constituent element may be substituted instead as long as the object of the present invention is achieved. Here, FIG. 1 is a schematic block diagram of the exposure apparatus 1 as the first embodiment of the present invention. As shown in FIG. 1, the exposure apparatus 1 includes an illuminating device 100 that illuminates a mask 200 on which a circuit pattern is formed, and a plate 400 that diffracts light generated from the illuminated mask pattern.
It has a projection optical system 300 for projecting onto a screen and a control section 500.

The exposure apparatus 1 is a projection exposure apparatus that exposes the circuit pattern formed on the mask 200 on the plate 400 by a step-and-scan method, and is suitable for a submicron or quarter-micron lithography process.

The illuminating device 100 illuminates the mask 200 on which a transfer circuit pattern is formed, and has a light source section 110 and an illuminating optical system 120.

The light source unit 110 uses, for example, a laser as a light source. The laser is Ar with a wavelength of about 193 nm.
An F excimer laser, a KrF excimer laser having a wavelength of about 248 nm, an F ₂ laser having a wavelength of about 153 nm, or the like can be used, but the type of laser is not limited to the excimer laser, and for example, a YAG laser may be used. The number of lasers is not limited either. For example, if two solid-state lasers that operate independently are used, there is no coherence between the solid-state lasers, and speckle due to the coherence is significantly reduced. Further, in order to further reduce speckle, the optical system may be swung linearly or rotationally. Further, the light source that can be used for the light source unit 110 is not limited to the laser, and one or a plurality of lamps such as a mercury lamp and a xenon lamp can also be used.

The illumination optical system 120 is an optical system for illuminating the mask 200, and includes a lens, a mirror, a light integrator, a diaphragm, and the like, which are provided in a stage subsequent to the light source unit 110 described later and in a stage upstream of the mask 200.

The light-reducing member 121 is composed of, for example, a plurality of light amount adjusting filters (ND filters) having different transmittances, and N is adjusted so as to obtain an optimum exposure amount on the surface of the plate 400.
It is combined by the D driving means 610, and fine adjustment of the extinction ratio is possible.

The beam shaping optical system 122 is composed of a plurality of optical elements and a zoom lens. The beam shaping optical system 122 is driven by the lens system driving unit 620 to control the intensity distribution and the angular distribution of the light flux incident on the optical integrator 123 in the subsequent stage to a desired distribution.

The optical integrator 123 is
It consists of two-dimensionally arranged multiple micro lenses,
A secondary light source is formed near the exit surface.

The diaphragm 124 is arranged in the vicinity of the exit surface of the optical integrator 123, and the diaphragm driving means 63.
When 0, the size and shape of the diaphragm are variable.

The condenser lens 125 condenses the light beams emitted from a plurality of secondary light sources formed in the vicinity of the emission surface of the optical integrator 123, and superimposes and irradiates the surface of the scan blade 128b, which is the surface to be irradiated, with the light. The surface is uniform.

The half mirror 126 reflects a few% of the luminous flux emitted from the optical integrator 123, and guides it to the integrated exposure amount detector 127.

The integrated exposure amount detector 127 is an illuminance meter for constantly detecting the light amount at the time of exposure, is arranged at a position optically conjugate with the mask 200 and the plate 400, and controls a signal according to its output. Send to Department 500.

The scan blade 128b is composed of a plurality of movable light-shielding plates, and the scan blade driving means 640 forms an arbitrary opening shape to regulate the exposure range on the surface of the plate 400. Further, the scan blade 128b scans and moves in the arrow direction in the figure in synchronization with the mask stage 250 and the plate stage 450. A variable slit 128a is arranged near the scan blade 128b in order to improve the illuminance uniformity on the exposure surface after scanning exposure.

The image forming lenses 129a and 129b are masks 2 whose surface to be illuminated is the opening shape of the scan blade 128b.
No. 00 surface, and a required area on the mask 200 surface is uniformly illuminated.

The mask 200 is made of, for example, quartz, on which a circuit pattern (or image) to be transferred is formed, is supported by the mask stage 250, and is driven by the mask stage driving means 650. The diffracted light emitted from the mask 200 passes through the projection optical system 300 and the plate 4
00 is projected. The plate 400 is an object to be processed such as a wafer or a liquid crystal substrate, and is coated with a resist.
The mask 200 and the plate 400 have a conjugate relationship.
In the case of a scanner, the pattern of the mask 200 is transferred onto the plate 400 by scanning the mask 200 and the plate 400. Mask 20 for stepper
Exposure is performed with 0 and the plate 400 kept stationary.

The projection optical system 300 includes a plurality of lenses 300.
This is a catadioptric type including a to n and reflecting members 300α to ζ, and a circuit pattern on the surface of the mask 200 is once imaged at an intermediate image forming position G and then reduced and projected onto the surface of the plate 400. In the present embodiment, the mirror 310 near the intermediate image forming position G is a half mirror, and the partially transmitted light is monitored by the detection unit 320.

The half mirror 310 reflects most of the light as exposure light and transmits some of the light for detection. The half mirror 310 has a P of reflected and transmitted light.
Since the balance between the polarized light and the S-polarized light may be lost, when the balance between the P-polarized light and the S-polarized light is largely lost, a reflection surface is formed so that an error does not occur between the light amount reaching the exposure surface and the light amount detected by the detection unit 320. It is necessary to optimally design the coating in. The detection unit 320 is placed at a position that is substantially optically conjugate with the intermediate image formation position G (and the plate 400), and detects the amount of light that has passed through the half mirror 310.

Therefore, it becomes possible to detect the light transmitted through a part of the illumination optical system 120 and the projection optical system 300 in real time, and more accurately monitor the exposure amount on the surface of the plate 400 as compared with the prior art, and more. High-precision exposure control can be performed. Details of such an exposure amount control method will be described later.

Photoresist is applied to the plate 400. The photoresist coating process includes a pretreatment, an adhesion improver coating treatment, a photoresist coating treatment, and a prebake treatment. The pretreatment includes washing, drying and the like. The adhesion improving agent coating treatment is a surface modification treatment (that is, hydrophobic treatment by applying a surfactant) for enhancing the adhesion between the photoresist and the base, and HMDS (Hexam)
An organic film such as ethyl-dilazane) is coated or vapor-treated. Prebaking, which is a baking (baking) step, is softer than that after development, and removes the solvent.

The plate stage 450 includes the plate 40
Support 0. Since the stage 450 may have any configuration known in the art, detailed description of its structure and operation will be omitted here. For example, the plate stage 450 can move the plate 400 two-dimensionally along the optical axis direction and a plane orthogonal to the optical axis. The plate stage 450 is controlled by the plate stage driving means 660. Stage 450
Is provided on, for example, a stage surface plate supported on the floor or the like via a damper, and the mask stage 250 and the projection optical system 300 are, for example, a base frame in which the lens barrel surface plate is placed on the floor or the like. It is provided on a lens barrel surface plate (not shown) which is supported above via a damper or the like.

The mask 200 and the plate 400 are synchronously scanned, for example, and the positions of the stage 450 and a mask stage (not shown) are monitored by, for example, a laser interferometer, and both are driven at a constant speed ratio. For example, when the reduction ratio of the projection optical system 300 is 1 / A, the scanning speed of the plate stage 450 is B (mm / sec).
At this time, the scanning speed of the mask stage 250 is AB (mm
/ Sec). The scanning direction of the mask stage 250 and the scanning direction of the plate stage 450 are opposite to each other.

The detector 452 is an illuminance meter for detecting the amount of exposure light incident on the surface of the plate 400. The detector 452 aligns the light receiving portion on the surface of the plate 400 and illuminates the illumination light within the illumination area on the plate stage 45.
It moves with the driving of 0, receives light, and sends a signal corresponding to the output to the control unit 500.

The control unit 500 receives the detection results of the integrated light amount detector 127 and the detection unit 320, and controls the exposure amount on the surface of the plate 400 via the driving means 610 to 660.

The method of controlling the exposure amount on the surface of the plate 400 (that is, the operation of the controller 500) will be described below with reference to FIG. Here, FIG. 2 is a flow chart for explaining the exposure amount control method of the present invention. First, the plate 40 for various lighting modes (such as annular lighting conditions)
The illuminance on the 0th surface is measured by the detector 452, output calibration is performed with the integrated light amount detection unit 127 in the illumination optical system 120, and the calibration result is stored (step 1000).

Next, the illuminance distribution on the exposed surface in various illumination modes is measured by moving the detector 452 two-dimensionally (when the detector 452 is a line sensor, moving it one-dimensionally) and performing scanning exposure. Then, conditions are set so that the illuminance distribution becomes uniform (step 1002). In this embodiment, the opening shape of the variable slit 128a is optimized.

When an arbitrary illumination mode is designated and the exposure amount on the surface of the plate 400 for that illumination mode is set, the scanning speed V (mm / s) of the plate stage 450 is set.
ec), the width W (m in the scanning direction of the variable slit 128a
m) and the laser oscillation frequency F (Hz) are respectively determined so as to satisfy the expression 1 (step 1004).

Next, the mask 200 on which the circuit pattern to be transferred is formed is arranged, and scanning exposure is performed while synchronizing the mask 200 and the plate 400 (step 10).
06). During scanning exposure, the amount of light reaching the detection unit 320 is periodically measured at an arbitrary timing (step 100
8) Then, the change in the transmittance of the optical system is sequentially calculated by detecting the change in the measurement signal (step 1010). On the other hand, the integrated exposure amount detector 127 monitors the integrated exposure amount (step 1012).

The exposure amount on the surface of the plate 400 is controlled by reflecting the change in the transmittance of the optical system obtained by the calculation on the integrated exposure amount detector 127 (step 1014). By such a method, more accurate exposure amount control is possible by performing feedback control with respect to the output of the light source unit 110 and the adjustment of the dimming member 121.

Here, the arbitrary timing at which the detecting section 320 measures the light amount in step 1008 will be described. FIG. 3 is a schematic diagram showing the mask 200 during scanning exposure. In the case of scanning exposure, as shown in FIG.
Since the mask 200 is scanned, for example, in the direction of the arrow in the figure, the mask pattern 202 sequentially passes through the slit-shaped exposure region R. Therefore, since the mask transmittance changes sequentially, the amount of light reaching the detection unit 320 constantly changes during exposure. Therefore, it is necessary to accurately grasp only the change in transmittance of the optical system in consideration of the timing measured by the detection unit 320.

FIG. 4 is a graph showing the results of monitoring the amount of light reaching the detector 320 during scanning exposure for two types of masks X and Y. In this figure, the horizontal axis represents time or stage movement distance, and the vertical axis represents the amount of light (signal intensity of the detection unit 320).

Referring to FIG. 4, the amount of light detected by the detector 320 fluctuates due to the influence of the mask pattern difference and the time within a shot (during scanning exposure). Have sex Therefore, the change in the transmittance of the optical system is detected by acquiring the integrated value of the detected light amount in the shot (total detected light amount in one shot) and the average value as one data and sequentially detecting the change for each data. Alternatively, the amount of light at a specific timing within a shot (a specific point in the scanning exposure area) may be set as one data, and the change may be sequentially detected.

In the exposure amount control method, the exposure amount may be directly controlled based on the light amount detected by the detector 320.
FIG. 5 is based on the amount of light detected by the detector 320 (that is,
6 is a flowchart for explaining an exposure amount control method (when the integrated light amount detection unit 127 is not used).

First, the illuminance on the surface of the plate 400 for various illumination modes (such as annular illumination conditions) is detected by the detector 4.
52, and the detection unit 320 in the projection optical system 300.
Output calibration is performed and the calibration result is stored (step 2000).

Next, the illuminance distribution on the exposed surface in various illumination modes is measured by moving the detector 452 two-dimensionally (when the detector 452 is a line sensor, moving it one-dimensionally) and performing scanning exposure. Then, conditions are set so that the illuminance distribution becomes uniform (step 2002). In this embodiment, the opening shape of the variable slit 128a is optimized.

When an arbitrary illumination mode is designated and the exposure amount on the surface of the plate 400 for that illumination mode is set, the scanning speed V (mm / s) of the plate stage 450 is set.
ec), the width W (m in the scanning direction of the variable slit 128a
m) and the laser oscillation frequency F (Hz) are respectively determined so as to satisfy Expression 1 (step 2004).

Next, the mask 200 on which the circuit pattern to be transferred is formed is placed, dummy scanning exposure is performed while the mask 200 and the plate 400 are synchronized, and the light amount during the scanning exposure (variation of mask transmittance). Is stored as a model (step 2006). Next, main exposure is started, and the amount of light during scanning exposure is measured in real time by the detector 320 (step 2008), and at the same time, step 20
The model is compared with the model of the light amount (fluctuation of mask transmittance) during the scanning exposure stored in 06 (step 2010).

Then, as a result of the comparison, when the difference from the model becomes larger than the predetermined amount set in advance, the control for approaching the model is sequentially performed to control the exposure amount on the surface of the plate 400 (step 2012). By this method,
By performing feedback control on the output of the light source unit 110 and the adjustment of the dimming member 121, more accurate exposure amount control is possible.

In the exposure, the light flux emitted from the light source unit 110 illuminates the mask 200 by the illumination optical system 120 after shaping it into a desired angular distribution and illuminance distribution. Mask 2
Light that passes through 00 and reflects the mask pattern is imaged on the plate 400 by the projection optical system 300. Since the exposure apparatus 1 can control the exposure amount of the plate 400 with high accuracy by performing the above-described exposure amount control method, it has excellent resolution and high throughput and is economical (device, semiconductor element, LCD element, Image sensor (CCD etc.),
Thin film magnetic heads, etc.) can be provided.

Next, with reference to FIG. 6, an exposure apparatus 2 as a second embodiment of the present invention will be described. FIG. 6 is a schematic block diagram of the exposure apparatus 2 as the second embodiment of the present invention. The exposure apparatus 2 of FIG. 6 is the same as the exposure apparatus 1 of FIG. 1, but the structure of the projection optical system 300 is different. The projection optical system 300 detects the light amount at the intermediate image formation position, whereas the projection optical system 300A detects the light amount near the pupil plane. The same members as those shown in FIG. 1 are designated by the same reference numerals, and a duplicate description will be omitted.

The exposure apparatus 2 has a reflecting member 330 near the pupil position in the projection optical system 300A, and the reflecting member 33 is provided.
By setting 0 as the half mirror, the light amount of the transmitted light from the half mirror is detected by the detection unit 320. In the present embodiment, the reflecting member 3 is provided near the pupil plane in the projection optical system 300A.
Since there is a half mirror of 30, the region where the light amount can be detected differs depending on the illumination mode. Therefore, a plurality of positions of the detection unit 320 are arranged so as to correspond to the normal illumination mode, the annular illumination mode, and the quadrupole illumination mode. The entire surface of the reflection member 330 may be a half mirror, but only the portion corresponding to the detection unit 320 may be a half mirror to improve the light use efficiency for exposure.

With the above configuration, it is possible to detect in real time the light that has passed through a part of the illumination optical system 120 and the projection optical system 300A, and monitor the exposure amount on the surface of the plate 400 more accurately than before. Therefore, exposure control with higher accuracy can be performed.

Further, by monitoring the change in the measured amount of light, the change in the transmittance of the optical system up to the vicinity of the surface of the wafer 400 can be detected. By reflecting such a change in transmittance in the result of the integrated light amount detector 127 and performing feedback control for the output of the light source unit 110 and the adjustment of the dimming member 121, more accurate exposure amount control is possible.

The exposure control method using the exposure apparatus 2 is also the same as the method described with reference to FIGS.

Next, an exposure apparatus 3 as a third embodiment of the present invention will be described with reference to FIG. FIG. 7 is a schematic block diagram of the exposure apparatus 3 as the third embodiment of the present invention. The exposure apparatus 3 of FIG. 7 is the same as the exposure apparatus 1 of FIG. 1, but the structure of the projection optical system 300 is different. The same members as those shown in FIG. 1 are designated by the same reference numerals, and a duplicate description will be omitted.

The projection optical system 300B is a catadioptric type optical system. The projection optical system 300B has an intermediate image forming position G
The half mirror 340 is arranged obliquely with respect to the optical axis on the mask 200 side near the surface, and the light amount of the reflected light from the half mirror 340 is detected by the detection unit 320.

Since the half mirror 340 may disturb the balance between the P-polarized light and the S-polarized light of the reflected and transmitted light, when the balance between the P-polarized light and the S-polarized light is greatly disturbed, the amount of light reaching the exposure surface and the detection are detected. It is necessary to optimally design the coating on the reflection surface so that an error does not occur in the light amount detected by the unit 320. (Alternatively, the reflection surface may be non-coated, a polarization adjusting element (not shown) may be provided immediately before the detection unit 320, and the coating on the transmission surface of the half mirror 340 may be optimized.) The detection unit 320 has an intermediate connection. The light amount of the light reflected by the half mirror 340, which is placed at a position substantially optically conjugate with the image position G (and the plate 400), is detected.

With the above configuration, it is possible to detect in real time the light that has passed through part of the illumination optical system 120 and the projection optical system 300B, and monitor the exposure amount on the surface of the plate 400 more accurately than before. Therefore, exposure control with higher accuracy can be performed.

By monitoring the change in the measured light quantity, the change in the transmittance of the optical system up to the vicinity of the surface of the wafer 400 can be detected. By reflecting such a change in transmittance in the result of the integrated light amount detector 127 and performing feedback control for the output of the light source unit 110 and the adjustment of the dimming member 121, more accurate exposure amount control is possible.

The exposure control method using the exposure apparatus 3 is also the same as the method described with reference to FIGS.

Next, an exposure apparatus 4 as a fourth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a schematic block diagram of the exposure apparatus 3 as the fourth embodiment of the present invention. The exposure apparatus 4 in FIG. 8 is similar to the exposure apparatus 3 in FIG. 7, but the structure of the projection optical system 300B is different. The projection optical system 300B detects the light amount at the intermediate image formation position, whereas the projection optical system 300C detects the light amount near the pupil plane. The same members as those shown in FIG. 1 are designated by the same reference numerals, and a duplicate description will be omitted.

The exposure apparatus 4 has a reflecting member 350 near the pupil position in the projection optical system 300C, and the reflecting member 35 is provided.
By setting 0 as the half mirror, the light amount of the transmitted light from the half mirror is detected by the detection unit 320. In the present embodiment, the reflecting member 3 is provided near the pupil plane in the projection optical system 300C.
Since there is a half mirror of 50, the region where the amount of light can be detected differs depending on the illumination mode. Therefore, a plurality of positions of the detection unit 320 are arranged so as to correspond to the normal illumination mode, the annular illumination mode, and the quadrupole illumination mode. Note that the entire surface of the reflecting member 350 may be a half mirror, but only the portion corresponding to the detection unit 320 may be a half mirror to improve the light use efficiency for exposure.

With the above structure, the light transmitted through the illumination optical system 120 and part of the projection optical system 300C can be detected in real time, and the exposure amount on the surface of the plate 400 can be monitored more accurately than before. Therefore, exposure control with higher accuracy can be performed.

Further, by monitoring the change in the measured light quantity, it is possible to detect the change in the transmittance of the optical system up to the vicinity of the plate 400 surface. By reflecting such a change in transmittance in the result of the integrated light amount detector 127 and performing feedback control for the output of the light source unit 110 and the adjustment of the dimming member 121, more accurate exposure amount control is possible.

The exposure control method using the exposure apparatus 4 is also the same as the method described with reference to FIGS.

Although the exposure apparatuses 1 to 4 are step-and-scan type exposure apparatuses, the same effect can be obtained even if they are step-and-repeat type exposure apparatuses. In the step-and-repeat method, since the mask pattern is fixed, the integrated value or the average value of the detected light amount for each shot is set as one data and the change may be detected to obtain the change in the transmittance of the optical system.

Next, with reference to FIGS. 9 and 10, an embodiment of a device manufacturing method using the above-mentioned exposure apparatuses 1 to 4 will be described. FIG. 9 is a flowchart for explaining the manufacture of devices (semiconductor chips such as IC and LSI, LCDs, CCDs, etc.). Here, manufacturing of a semiconductor chip will be described as an example. In step 1 (circuit design), the device circuit is designed. In step 2 (mask manufacturing), a mask having the designed circuit pattern is manufactured. In step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by a lithography technique using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer created in Step 4, and an assembly process (dicing,
Bonding), packaging process (chip encapsulation), etc. are included. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (step 7).

FIG. 10 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. Step 12 (CV
In D), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition or the like. In step 14 (ion implantation),
Implant ions into the wafer. In step 15 (resist processing), a photosensitive agent is applied to the wafer. Step 16
In (exposure), the exposure circuit 1 to 4 exposes the circuit pattern of the mask onto the wafer. In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist image are removed. In step 19 (resist peeling), the unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer. According to the manufacturing method of this embodiment,
It is possible to manufacture higher quality devices than ever before.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to these, and various modifications and changes can be made within the scope of the gist thereof.

[0089]

According to the exposure apparatus and method of the present invention, even during the exposure step, the change in transmittance of all optical systems including the projection optical system is constantly measured, and the integrated exposure amount is controlled more accurately. You can Also, because the measurement is performed during the exposure process,
It is possible to immediately respond to changes over time in the optical system and atmosphere. A device manufacturing method using such an exposure apparatus and method has improved throughput and can manufacture high-quality devices.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an exposure apparatus as a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining an exposure amount control method of the present invention.

FIG. 3 is a schematic diagram showing a mask during scanning exposure.

FIG. 4 is a graph showing the results of monitoring the amount of light detected during scanning exposure for two types of masks.

FIG. 5 is a flowchart for explaining another exposure amount control method of the present invention.

FIG. 6 is a schematic block diagram of an exposure apparatus as a second embodiment of the present invention.

FIG. 7 is a schematic block diagram of an exposure apparatus as a third embodiment of the present invention.

FIG. 8 is a schematic block diagram of an exposure apparatus as a fourth embodiment of the present invention.

FIG. 9 is a flowchart for explaining a device manufacturing method having the exposure apparatus of the present invention.

FIG. 10 is a detailed flowchart of step 4 shown in FIG.

FIG. 11 is a schematic block diagram of a conventional exposure apparatus.

[Explanation of symbols]

1, 2, 3, 4 Exposure devices 300, 300A, 300B, 300C Projection optical systems 300a to n Lenses 300α to ζ, 330, 350 Reflecting members 310, 340 Half mirror 320 Detection unit 500 Control unit

Claims (20)

[Claims] 1. A projection optical system for projecting a pattern formed on a mask onto an object to be processed, wherein a reflection optical member for generating a divided light beam by dividing an incident light beam and a light quantity of the divided light beam are detected. An exposure apparatus comprising: a projection optical system having a detection unit; and a control unit that controls the amount of light projected onto the object to be processed based on the detection result of the detection unit. 2. A catadioptric optical system for projecting a pattern formed on a mask onto an object to be processed, wherein the catoptric optical member generates a split light flux by reflecting and transmitting an incident light flux, and the split light flux. An exposure apparatus comprising: a projection optical system having a detection unit that detects the amount of light; and a control unit that controls the amount of light projected onto the object to be processed based on the detection result of the detection unit. 3. A projection optical system for projecting a pattern formed on a mask onto an intermediate image plane and then re-projecting it onto a target object, wherein the reflection optical system reflects and transmits an incident light beam to generate a divided light beam. An exposure apparatus that includes a projection optical system that includes an optical member and a detection unit that detects the light amount of the divided light flux, and a control unit that controls the light amount projected onto the object to be processed based on the detection result of the detection unit. 4. The exposure apparatus according to claim 3, wherein the optical member is provided between the optical member adjacent to the intermediate image surface and the intermediate image surface. 5. The exposure apparatus according to claim 4, wherein the optical member is located closer to the mask than the intermediate image plane and is arranged obliquely with respect to the optical axis. 6. The exposure apparatus according to claim 1, wherein the optical member is arranged at a pupil position of the projection optical system. 7. The exposure apparatus according to claim 1, wherein the divided luminous flux is reflected light reflected by the optical member or transmitted light transmitted through the optical member. 8. The exposure apparatus according to claim 3, wherein the detection unit is arranged at a position optically conjugate with a position where the intermediate image is formed. 9. The exposure according to claim 1, wherein the projection optical system is an optical system having at least a reflecting member, and the optical member is the reflecting member having a positive or negative refractive power of the projection optical system. apparatus. 10. The exposure apparatus according to claim 1, wherein the optical member is a half mirror. 11. The illumination optical system according to claim 1, further comprising an illumination optical system provided with an integrated light amount detection means for detecting an integrated light amount at a position optically conjugate with the mask and the object to be processed. The exposure apparatus described. 12. A light beam reflected or transmitted through a mask arranged on a surface to be illuminated is used as exposure light, and the exposure light is projected onto a target object through a projection optical system to expose the target object. An exposure method, comprising: a step of setting a light amount on the object to be processed for an arbitrary illumination mode; and a first detecting step of detecting a light amount in the projection optical system, the first detecting step An exposure method for exposing the object to be processed so that the light amount on the object is the light amount set in the setting step. 13. A second detecting step of detecting a light amount at a position conjugate with the illuminated surface and / or the object to be processed during exposure, and a light amount detected in the second detecting step and the first detecting step. And a step of calculating a change amount with respect to the light amount detected in the first detection step, and by reflecting the change amount in a detection result of the second detection step, the light amount on the object to be processed is The exposure method according to claim 12, wherein the exposure is performed so that the light amount set in the setting step is obtained. 14. An exposure method for exposing an object to be processed by projecting exposure light onto the object to be processed through a projection optical system, wherein the step of setting the amount of light on the object to be processed for an arbitrary illumination mode. And a step of storing a change in the light amount on the surface of the object to be processed when performing exposure based on the light amount set in the setting step, and a light amount at a substantially pupil position or a substantially intermediate imaging position of the projection optical system. And a step of detecting the light amount on the object to be processed based on the change in the light amount detected in the detecting step and the change in the stored light amount so as to be the light amount set in the setting step. And an exposure method. 15. The exposure method according to claim 12, wherein the detecting step is always performed during exposure. 16. The exposure method according to claim 12, wherein the detecting step is periodically performed at a predetermined timing. 17. An exposure apparatus having an exposure mode for performing exposure according to the exposure method according to claim 12. 18. A projection optical system for projecting a pattern on an object plane onto an image plane, the projection optical system comprising: a half mirror; and a detection section for detecting a light quantity of a light beam extracted through the half mirror. system. 19. A projection optical system comprising at least a reflecting member for projecting a pattern on an object plane onto an image plane, wherein the reflecting member is a half mirror, and the light quantity of the light flux extracted by the half mirror is A projection optical system having a detection unit for detecting. 20. A step of projecting and exposing the object to be processed using the exposure apparatus according to any one of claims 1 to 11, and a predetermined process for the object to be projected and exposed. A method of manufacturing a device, the method comprising: