JP5593690B2 - Deformation measurement substrate, exposure apparatus, exposure method, and device manufacturing method - Google Patents

Description

  The present invention relates to a deformation measurement substrate, an exposure apparatus, an exposure method, and a device manufacturing method.

  Conventionally, in a photolithography process which is one of manufacturing processes of a semiconductor element, a liquid crystal display element, a thin film magnetic head, and other micro devices, a mask or a reticle (hereinafter, these are collectively referred to as a “mask”). An exposure apparatus that transfers a formed pattern onto a substrate such as a semiconductor wafer (hereinafter abbreviated as a wafer) or a glass plate coated with a photosensitive agent such as a photoresist via a projection optical system is used. As one of the exposure methods used in such an exposure apparatus, a step-and-repeat method is known. In this step-and-repeat method, a pattern formed on a reticle is exposed to a predetermined shot area (exposure area) set on the wafer, and then the wafer stage is moved step by step by a predetermined distance, The other shot area is exposed, and this operation is repeated for all the shot areas set on the wafer, thereby transferring the pattern image formed on the reticle to the entire wafer. An exposure apparatus that employs this step-and-repeat method is called a stepper and is widely used in the manufacturing process of semiconductor elements and the like.

  In such an exposure apparatus, an alignment technique called enhanced global alignment (EGA) is used in order to align the reticle and the wafer with high accuracy. This EGA images fine alignment marks formed in association with several typical (3 to 9) shot areas provided on a wafer, and performs statistical calculations based on the imaging results. The alignment coordinates of all the shot areas set on the wafer are obtained with high accuracy, and the reticle and the wafer are aligned based on the arrangement coordinates of each shot area (see, for example, Patent Document 1). ).

By the way, in the alignment described above, an alignment mark is imaged for several representative shot areas, and statistical calculation is performed based on the imaging results to obtain the array coordinates of all shot areas, and therefore there is a possibility that an error component is included. is there.
Thus, conventionally, it has been considered to obtain a deformation amount for each shot region by attaching a strain gauge to each shot region.

JP-A-8-316135

However, the following problems exist in the conventional technology as described above.
There is a problem that it takes a lot of time and effort to reduce the work efficiency to attach a minute strain gauge to each of a plurality of shot areas. In particular, when a plurality of deformation detection directions are set, it is necessary to attach a strain gauge for each detection direction, which causes a problem that work efficiency is further reduced.
Therefore, since a plurality of strain gauges are formed on a single manufacturing substrate in the manufacturing process and then divided into a single strain gauge, a manufacturing substrate on which the plurality of strain gauges are formed is provided. It is conceivable to measure the amount of deformation in the shot area, but in order to function as a strain gauge, it is necessary to mount (paste) other parts in each shot area, and the amount of deformation can be easily measured. It is not a thing.

  The present invention has been made in consideration of the above points, and a deformation measurement substrate, an exposure apparatus, and an exposure method that can easily measure information related to deformation of an exposure region on the substrate without causing a reduction in work efficiency. An object of the present invention is to provide a device manufacturing method.

In order to achieve the above object, the present invention adopts the following configuration showing an embodiment.
The deformation measurement substrate of the present invention is provided in each of a plurality of irradiation regions on the substrate where exposure light irradiation processing is performed, and a deformation measurement device that measures information related to deformation in each irradiation region, and deformation of the substrate due to temperature. And a second deformation measurement device that measures information related to the deformation measurement device independently of the deformation measurement device, and the deformation measurement device and the second deformation measurement device are formed by patterning by the exposure light irradiation process. Is.

Therefore, in the deformation measurement substrate of the present invention, the deformation measurement device and the second deformation measurement device are patterned by using exposure light, so that the deformation measurement device and the second deformation measurement device are attached or other components are attached. There is no need for mounting, and the deformation measurement substrate can be used for measurement as it is. Therefore, in the present invention, it is possible to easily measure the deformation amount for each exposure region on the substrate without causing a reduction in work efficiency.
Further, in the present invention, in each irradiation region, for example, a deformation in a state in which a deformation caused by an adsorption pressure when adsorbing and holding the substrate and a thermal deformation caused on the substrate due to a temperature change due to the substrate conveyance or the like are combined is measured. The thermal deformation is measured by a second deformation measuring device. Therefore, in the present invention, since the deformation amount caused by the adsorption pressure and the heat deformation amount can be separated, it is possible to effectively take measures according to each deformation.

An exposure apparatus according to the present invention is an exposure apparatus that has a substrate stage that moves while holding a substrate, and that exposes a pattern image on the substrate, the deformation measurement device and the second deformation measurement device described above. And a correction device that corrects information regarding the position where the pattern image is formed based on the measurement result.
The exposure method of the present invention is an exposure method for exposing a pattern image to a substrate, and information on deformation in an exposure region on the substrate is obtained using the deformation measurement device and the second deformation measurement device described above. A step of measuring.
Therefore, the exposure apparatus and the exposure method of the present invention can correct the information regarding the position where the pattern image is formed based on the deformation amount of the substrate measured easily and with high accuracy, and can efficiently perform the correction on the substrate. It becomes possible to form a pattern aligned with accuracy.

The device manufacturing method of the present invention uses the exposure method described above.
Therefore, in the device manufacturing method of the present invention, it is possible to efficiently manufacture a device in which patterns are aligned with high accuracy.
In order to explain the present invention in an easy-to-understand manner, the description has been made in association with the reference numerals of the drawings showing one embodiment, but it goes without saying that the present invention is not limited to the embodiment.

  In the present invention, the deformation measurement substrate can be used for measurement as it is, information on the deformation of the irradiation region on the substrate can be easily measured without causing a reduction in work efficiency, and the deformation can be determined according to the cause of the deformation. High-precision exposure processing can be realized by taking appropriate measures.

1 is a view showing an embodiment of the present invention, and is a schematic block diagram of an exposure apparatus. FIG. 6 is a plan view of a measurement wafer WA in which a plurality of shot areas SA are set. It is the detailed drawing which expanded one of shot area SA. It is the detailed drawing which expanded one of flexure parts FL. FIG. It is a figure which shows the relationship between the time of adsorption | suction distortion and temperature distortion, and distortion amount. It is a figure which shows the design position of the flexure part FL, and the position at the time of a deformation | transformation. It is the detailed drawing which expanded one of shot areas SA in a 2nd embodiment. It is the figure which showed typically one of the same shot area SA. It is a figure which shows another form of the flexure part FL. 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.

Embodiments of a deformation measurement substrate, an exposure apparatus, an exposure method, and a device manufacturing method according to the present invention will be described below with reference to FIGS.
First, an exposure apparatus using a deformation measurement substrate will be described.
Here, for example, as an exposure apparatus, a scanning exposure is performed in which a circuit pattern of a semiconductor device formed on a reticle is transferred onto the wafer while the reticle and the wafer are synchronously moved in different directions (reverse directions) in the scanning direction. A description will be given using an example in which an apparatus (scanning stepper) is used. In this exposure apparatus, an example in which information about deformation in a shot area (exposure area, irradiation area) irradiated with exposure light on a wafer is measured using the deformation measurement substrate of the present invention is used. explain.

  FIG. 1 schematically shows a configuration of a reduction projection type exposure apparatus 1 for manufacturing a semiconductor device preferably used in this embodiment. First, the overall configuration of the exposure apparatus 1 will be described below.

  The exposure apparatus 1 includes an illumination system 2 that illuminates a reticle R as a mask with an energy beam (exposure light) from an exposure light source (not shown), and a wafer (substrate) W that uses exposure light emitted from the reticle R as an object. It includes a projection optical system PL for projecting above, a reticle stage RS for holding a reticle R, a wafer stage WS for holding a wafer W, a main control unit 30 for overall control of the entire apparatus, and the like.

  The illumination system 2 includes various lens systems such as a relay lens, a fly-eye lens (or lot integrator), a condenser lens (not shown), a blind disposed at a position conjugate with the aperture stop and the pattern surface of the reticle R, and the like. The illumination light from the exposure light source is irradiated in a predetermined illumination area on the reticle R with a uniform illuminance distribution.

  The projection optical system PL includes a plurality of lenses (not shown), reduces the illumination light transmitted through the reticle R to a predetermined reduction magnification β (β is, for example, 1/4, 1/5, etc.) Projection exposure is performed on a wafer W coated with a photosensitive material (such as a photoresist). Here, the direction parallel to the optical axis AX of the projection optical system PL (the normal direction of the surface of the wafer W) is the Z direction, and the relative scanning direction of the reticle R and the illumination area in a plane perpendicular to the optical axis AX. The (direction perpendicular to the paper surface) is the Y direction, the non-scanning direction orthogonal to the X direction is the X direction, and the rotation direction about the axis parallel to the optical axis AX of the projection optical system PL is the θ direction.

  Reticle stage RS is configured to be moved one-dimensionally in the Y direction (scanning direction at the time of scanning (scanning) exposure) by a driving device (not shown) and finely driven in the X direction and θ direction. . The positions of the reticle stage RS in the X direction, Y direction, and θ direction are constantly monitored by a measuring device (not shown) such as a laser interferometer, and the position information obtained thereby is supplied to the main control unit 30.

  The wafer stage WS includes an XY stage 3 that can be driven in a two-dimensional plane (in the XY plane in FIG. 1), and a Z leveling stage 4 that holds the wafer W by suction and can be driven minutely in the Z direction on the XY stage 3. And disposed on a base (not shown). The XY stage 3 has a driving device 28 composed of, for example, a magnetically levitated two-dimensional linear actuator, and performs positioning and movement of the wafer W to a predetermined position under the command of the main control unit 30. At the time of scanning exposure, the XY stage 3 performs scanning movement in the scanning direction (Y direction) in synchronization with the reticle stage RS.

The Z leveling stage 4 has a drive mechanism (not shown), and moves the wafer W minutely in the Z direction under the command of the main control unit 30. Further, the Z leveling stage 4 is provided with a holding mechanism (not shown) for sucking and holding the wafer W from below (−Z side) and lift pins (not shown) for lifting and lowering the wafer W by sucking and holding. .
The positions of the Z leveling stage 4 in the X direction, the Y direction, and the θ direction are constantly monitored by a measuring device 33 such as a laser interferometer, and the position information obtained thereby is supplied to the main control unit 30.

  Similarly to the reticle stage RS, the positions of the wafer stage WS in the X direction, the Y direction, and the θ direction are constantly monitored by a measuring device (not shown) such as a laser interferometer, and the position information obtained thereby is the main control. The unit 30 is supplied.

  Above the wafer stage WS, an AF sensor 5 for measuring the position in the Z direction (normal direction) of the surface (exposure surface) of the wafer W is provided. The AF sensor 5 receives a light transmission system 6 that irradiates slit light to the surface of the wafer W through a plurality of slits from an oblique direction, and reflected light (reflected slit light) reflected by the surface of the wafer W, respectively. And a height position (focus amount) in the Z direction of the surface of the wafer W with respect to the imaging surface of the projection optical system PL based on a detection signal obtained from the reflected light from the surface of the wafer W. It is configured to calculate.

  In this exposure apparatus 1, when the circuit pattern of the reticle R is transferred onto the wafer W, the Z leveling stage 4 is driven based on the focus amount calculated by the AF sensor 5 to move the wafer W in the Z direction. Then, a focusing (main AF) operation for adjusting the surface of the wafer W within the focal depth of the projection optical system PL is performed. In parallel with this, the XY stage 3 is driven to step the wafer W by a predetermined amount in the X and Y directions within the XY plane perpendicular to the optical axis AX of the projection optical system PL. The image of the circuit pattern of the reticle R is sequentially transferred to each of the shot areas set to.

  At this time, the exposure apparatus 1 performs an alignment operation for aligning the center of each shot area of the wafer W with the optical axis AX (exposure position) of the projection optical system PL. This alignment operation is performed based on position information of alignment marks formed on the reticle R and the wafer W. The mark on the reticle R is detected by the reticle alignment system 8, and the mark on the wafer W is detected by the wafer alignment system 10 as an imaging optical system.

Next, configuration examples of the reticle alignment system 8 and the wafer alignment system 10 will be described.
In this embodiment, the reticle alignment system 8 is a so-called TTR method (through-through) that simultaneously detects a reticle mark RM formed on the reticle R and a reference mark FM provided on the Z leveling stage 4 by an imaging method. (The reticle type) image detection optical system is used. The reticle R is aligned based on the position information (X coordinate, Y coordinate) of the reticle mark RM measured by the reticle alignment system 8 so that the center of the reticle R coincides with the optical axis AX of the projection optical system PL. . Note that the distance between the reticle mark RM and the center of the reticle R is a predetermined value in design, and this value is subjected to arithmetic processing based on the reduction magnification of the projection optical system PL, whereby the image plane side of the projection optical system PL is processed. The distance between the projection point of reticle mark RM (on the wafer side) and the center of projection optical system PL is calculated. This distance is used as a correction value when each shot area on the wafer W is placed in the field of view of the projection optical system PL. Further, the reference mark FM is formed on the Z leveling stage 4 so as to have the same shape as the alignment mark (wafer mark) formed on the wafer W, for example, so as to be almost the same height as the surface of the wafer W. It is formed on the provided reference mark plate.

  The wafer alignment system 10 uses an FIA system that captures an image of a wafer mark, emits a light beam having a predetermined broadband wavelength as a measurement beam, and captures an image of the wafer mark formed on the wafer W, thereby obtaining a wafer mark. The position of is detected.

(First Embodiment of Measurement Wafer)
Next, a measurement wafer for measuring information related to the deformation of the wafer W will be described.
FIG. 2 is a plan view of a measurement wafer (deformation measurement substrate) WA in which a plurality of shot areas (irradiation areas) SA are set on the substrate B, and FIG. 3 is an enlarged view of one of the shot areas SA. FIG.

The measurement wafer WA is used to measure the deformation of the wafer W used for actual exposure, and a strain gauge (deformation measurement device) G and strain gauge ( The second deformation measuring device) G2 is formed.
A plurality of (here, 13) shot areas SA identical to the wafer are set in the measurement wafer WA, and a plurality (here, nine) of strain gauges G are arranged in each shot area SA. .

  As shown in FIG. 3, the strain gauges G are arranged in a plurality of rows (3 rows × 3 rows) at intervals in the X direction and the Y direction. Each strain gauge G includes a strain gauge (first measurement unit) GY for measuring deformation (strain) in the Y direction (first direction) and a strain gauge (for measuring deformation (strain) in the X direction (second direction). (Second measuring unit) GX.

  The strain gauges G2 are arranged in a plurality (four in this case) of flexure portions FL provided at corner portions on the substrate B that are out of the shot area SA. Further, as shown in FIG. 4, each strain gauge G <b> 2 also has a strain gauge (first measurement unit) G <b> 2 </ b> Y that measures deformation (strain) in the Y direction, and deformation (strain) in the X direction. ) To measure a strain gauge (second measurement unit) G2X.

As shown in FIG. 5, the flexure portion FL is formed in a rectangular shape by a rectangular groove portion 41 formed on the front surface of the substrate body BH and a rectangular concave portion 42 formed on the back surface and substantially the same as the outer shape of the groove portion 41. A rectangular island portion connected to the substrate main body BH by a thin plate-like connection portion 43 formed in the shape of FIG. The flexure portion FL is rigidly connected to the substrate body BH in a direction parallel to the surface of the substrate body BH (that is, a direction parallel to the XY plane) by the connection portion 43 substantially parallel to the XY plane. With respect to the direction (eg, Z direction, θY direction, θX direction) that intersects with the substrate main body BH, it is flexibly connected. Further, the concave portion 42 is formed at a position where the negative pressure suction force by the above-described holding mechanism does not act and the suction pin is not held by the lift pin.
In addition, the said groove part 41 and the recessed part 42 can be formed by passing through a photolithographic process etc., for example.

As these strain gauges G and G2 (GY, GX, G2Y, G2X), a semiconductor strain gauge using an electro-strain effect that generates an electric field when strain occurs, or an electrical resistance value changes when strain occurs. A utilized linear strain gauge (foil strain gauge) or the like is used, and the silicon substrate B is formed by the exposure processing by the exposure apparatus 1.
In addition, as a method of forming a semiconductor strain gauge on the silicon substrate B, since it is described in detail in JP-A-7-131036, JP-A-5-264380, JP-A-5-164636, etc., The description is omitted here.

Further, as a method of forming a linear strain gauge (foil strain gauge) on the silicon substrate B, as in the case of forming a wiring pattern on the wafer W, a known photolithography method using the exposure apparatus 1 is used. It can be formed by forming a line pattern (foil pattern) with a conductive material.
In this case, the deformation in the detection direction that occurs in the silicon substrate B can be detected by setting the extending direction of the line pattern as the deformation detection direction.

  The strain gauges G (GX, GY) and the strain gauges G2 (G2X, G2Y) are connected to lead wires L, L2 for outputting a detection result and flowing current, respectively. These lead wires L and L2 are routed on the silicon substrate B with a gap therebetween so as not to short-circuit, and are provided for each lead wire L and L2, as shown in FIG. The electrodes are connected to electrodes (output units) E that are arranged in the vicinity of the upper edge on the −X side.

For the measurement wafer WA placed on the wafer stage WS, an input device (not shown) such as a contact probe provided in the exposure apparatus 1 abuts on the electrode E, so that the strain gauges G and G2 are measured. The result is input to the main control unit 30. Further, this contact operation may supply necessary power to each strain gauge formed on the measurement wafer WA. For example, a battery such as a capacitor can be built in the measurement wafer WA and can be configured to be charged when the electrode E comes into contact therewith. Moreover, you may make it incorporate the battery instead of a battery.
In addition, it is good also as a structure which acquires the measurement result of the strain gauge G not by said contact system but by a non-contact system. Specifically, when patterning the strain gauge G on the measurement wafer WA, an antenna circuit capable of wireless communication is formed by patterning, and an external transceiver (not shown) and at least electromagnetic wave or capacitive coupling A configuration may be employed in which at least one of power supply and data exchange is performed by one. As a configuration for transmitting the measurement result of the sensor or the like to the control unit in a non-contact manner, for example, the one disclosed in JP-A-62-133829 can be used.

  The measurement wafer WA can be subjected to processing equivalent to the preprocessing (photosensitive agent coating processing, development processing, etc.) of the wafer W for exposure processing, and can cause deformation equivalent to the deformation generated in the wafer W. Become. When the pre-processed measurement wafer WA is placed on the wafer stage WS, the strain gauges GY and GX are output for all the shot areas SA by bringing the input device into contact with the electrode E. And the outputs of the strain gauges G2Y and G2X in the flexure part FL are detected.

Then, the main control unit 30 obtains deformation of each shot area SA in the X direction and Y direction from the measurement results of the strain gauges GY and GX, and performs deformation in the flexure portion FL from the measurement results of the strain gauges G2Y and G2X. It calculates | requires about each of a X direction and a Y direction. Here, as shown in FIG. 6, the deformation generated in the measurement wafer WA is a strain HV (hereinafter referred to as an adsorption strain HV) generated by a negative pressure suction force by a holding mechanism, a lift pin, or the like when being held by the Z leveling stage 4. And a strain HT caused by a temperature change that has occurred before being conveyed to the Z leveling stage 4 (hereinafter referred to as a temperature strain HT).
Therefore, the deformation of each shot area SA obtained from the measurement results of the strain gauges GY and GX is measured by adding the adsorption strain HV and the temperature strain HT.

  On the other hand, in the flexure portion FL where the strain gauges G2Y and G2X are arranged, the temperature strain HT is transmitted from the substrate body BH via the connection portion 43, but the adsorption strain HV is deformed at the connection portion 43. It is not transmitted from the substrate body BH to the flexure part FL. Therefore, the deformation measured by the strain gauges G2Y and G2X arranged in the flexure part FL becomes a temperature strain HT generated in the substrate B due to a temperature change.

Therefore, the main control unit 30 subtracts the deformation amount measured by the strain gauges G2Y and G2X from the deformation amount of each shot area SA obtained from the measurement results of the strain gauges GY and GX, thereby obtaining the change in each shot area SA. The adsorption strain HV can be obtained.
Here, as the temperature strain HT generated in each shot area SA, for example, the average value of the measured values of the strain gauges G2Y and G2X measured by the four flexure parts FL, or the flexure part FL closest to the shot area SA. The measured values of the strain gauges G2Y and G2X that have been measured can be used.

Then, with respect to the temperature distortion HT generated in the substrate B, the wafer does not cause a large difference between the temperature of the Z leveling stage 4 as a wafer holder and the temperature of the wafer W until the wafer is transferred to the Z leveling stage 4. The temperature of the transfer device for transferring W, the ambient temperature, the cooling temperature by the cool plate, and the like are adjusted.
For example, when the difference between the temperature adjusted by the cool plate and the temperature of the Z leveling stage 4 is clear, the temperature drop that occurs on the wafer W before being transferred from the cool plate to the Z leveling stage 4 is corrected. In the cool plate, a procedure for adjusting the temperature so that the temperature of the wafer W is increased by the correction value can be suitably selected.

  On the other hand, with respect to the suction strain HV generated on the substrate B, the suction strain HV is minimized by adjusting the suction pressure with respect to the wafer W by the holding mechanism and the lift pins and the moving speed of the lift pins that hold and lift the wafer W. .

When the above-described temperature, adsorption state, or the like is adjusted, the deformation of each shot area SA is obtained for each of the X direction and the Y direction again from the measurement results of the strain gauges GY, GX and the strain gauges G2Y, G2X. The difference from the ideal lattice is stored as a correction amount (magnification correction amount) for each direction.
Note that the deformation measurement using the measurement wafer WA may be set to be performed at regular intervals, for example, every time the wafer W is replaced or every lot before the wafer W exposure processing.

Next, an example of the alignment operation in the present embodiment will be described.
On the wafer W, a plurality of partitioned shot areas corresponding to the shot area SA of the measurement wafer WA, that is, areas to which an image of a circuit pattern formed on the reticle R is transferred are formed. Corresponding to the above, a wafer alignment mark (mark) that is observed when measuring a position in a two-dimensional plane on the wafer is formed on a predetermined layer (for example, the first layer). The alignment mark extends in the X direction at an interval and is observed when measuring the position of the wafer W in the X direction, and the alignment mark extends in the Y direction at an interval to measure the position in the Y direction. This is a line-and-space mark consisting of a wafer mark observed at the time. These alignment marks are formed on street lines on the wafer W, for example. The form of the alignment mark is not limited to this, and a two-dimensional mark having line and space marks arranged in a two-dimensional direction within one mark (for example, a special application filed by the present applicant). Application No. 8-311410) or a two-dimensional line mark arranged in a box shape. Note that search marks for search alignment are also formed on the wafer W corresponding to each shot area, but are not shown here.

  Each wafer alignment mark is arranged in a scribe line (street line) so as to have the same positional relationship with respect to the center of a predetermined shot area. In the present embodiment, each shot area on the wafer W is aligned by an EGA (Enhanced Global Alignment) method disclosed in, for example, Japanese Patent Laid-Open No. 61-44429.

In the EGA method, the main control unit 30 detects wafer marks in at least three shot areas selected as alignment shot areas among all shot areas by the wafer alignment system 10, and each alignment shot is based on the detection result. Find the coordinate position of the region. Subsequently, for the model function representing the arrangement of shot areas on the wafer W, the obtained coordinate position and a known coordinate position (design value, etc.) are substituted for each alignment shot area, and the least square method is used. Six shot arrangement error parameters (EGA parameters) of X shift, Y shift, X scale, Y scale, rotation, and orthogonality are calculated by statistical calculation. Based on these EGA parameters, design coordinate positions are corrected for all shot areas on the wafer W, and in particular, the projection optical system PL is connected based on scaling parameters (X scale, Y scale). Adjust the image characteristics.
Each shot area of the wafer W is driven by driving the wafer stage WS in the X direction and the Y direction based on the movement amount determined by the calculated coordinate position and the baseline amount of the wafer alignment system 10 described above. Is aligned with the optical axis AX of the projection optical system PL.

Thereafter, in the exposure apparatus 1, the wafer W is sequentially positioned at the exposure position (transfer position) via the driving device 28, and the pattern formed on the reticle R is sequentially transferred onto each positioned shot area. (Scanning exposure).
Here, the parameter (scale) obtained by the above-described EGA measurement is obtained comprehensively based on the result of detecting the wafer mark in the alignment shot area, and includes an error for each shot area. There is a case.
Therefore, the main control unit 30 serves as a correction device at a position where a pattern image is formed on the wafer W according to deformation (extension / contraction) in each direction for each shot area SA measured by the strain gauges GY, GX. • Correct the magnification.

Specifically, for the scale error in the non-scanning direction (X direction) of the shot area SA, the main control unit 30 determines the imaging characteristics (projection magnification) of the projection optical system PL when exposing the shot area SA. The scale error in the scanning direction (Y direction) is corrected by adjusting the scanning speed of the wafer stage WS.
As a result, the pattern image of the reticle R is projected onto each shot area at an appropriate magnification according to the deformation of the wafer W (each shot area).

  As described above, in this embodiment, since the strain gauges G and G2 are formed by patterning on the measurement wafer WA by exposure processing, the strain gauges G and G2 are attached to the measurement wafer WA or other components are mounted. It is not necessary, and it is possible to easily measure information related to the deformation of the shot area SA using the measurement wafer WA without reducing work efficiency. In addition, since there is no separate component for functioning as a strain gauge, the state of the force acting on the substrate is set to a state close to that of the substrate used for actual exposure processing, and measurement under the same environment as this substrate is possible. It is also possible to do this.

In the present embodiment, in each shot SA area, for example, the deformation caused by the adsorption pressure when the substrate B is held by suction and the thermal deformation caused by the temperature change due to the substrate transport or the like are combined. Since the deformation can be measured by the strain gauge G and the thermal deformation can be measured by the strain gauge G2, it is possible to separate the deformation amount caused by the adsorption pressure from the thermal deformation amount, so that the countermeasures according to each deformation are effective. Therefore, the deformation of the wafer W can be minimized.
In particular, in the present embodiment, the strain gauge G2 is disposed in the flexure portion FL that is rigidly connected to the substrate body BH in a direction parallel to the surface and flexibly connected in a direction intersecting this direction. Only the temperature deformation of the substrate B can be easily measured with a simple configuration. In the present embodiment, since the deformation in the X direction and the Y direction is individually measured for each shot area SA, the deformation of the shot area SA can be measured more accurately, and a pattern image is formed. It is possible to manufacture a high-quality device by correcting the position to be performed with higher accuracy.

  Moreover, in this embodiment, the electrodes E from which the measurement results of the strain gauges G and G2 (GY, GX, G2Y, and G2X) are output are gathered and arranged, so that each measurement result is obtained with a small input device. As a result, it is possible to prevent an increase in the size of the apparatus and to obtain measurement results of a large number of strain gauges G effectively, thereby improving the measurement work efficiency.

  In the above-described embodiment, the information for adjusting the temperature, the attractive force, and the like is obtained using the results measured by the strain gauges G and G2. However, as shown in FIG. The deformation positions FL11 to FL14 are obtained from the design results of the flexure portions FL1 to FL4 from the measurement results of the strain gauges G2 arranged in FL1 to FL4), and the deformation occurs on the substrate B (wafer W). The rotation component in the θZ direction (direction around the Z axis) can also be obtained.

(Second Embodiment of Measurement Wafer)
Next, a second embodiment of the measurement wafer will be described.
In the first embodiment, the strain gauge G2 is provided in the corner portion on the substrate B that is out of the shot area SA. In the second embodiment, the strain gauge G2 is provided in each shot area SA.
That is, as shown in FIG. 8, in this embodiment, a flexure portion FL is provided at a substantially central portion of each shot area SA. The strain gauges G2Y and G2X are disposed in the flexure portion FL.
Other configurations are the same as those of the first embodiment.

In the above configuration, the strain gauge G2Y provided in the same shot area SA as the strain gauges GY and GX, based on the deformation amount of each shot area SA obtained by the main control unit 30 from the measurement results of the strain gauges GY and GX. By subtracting the deformation amount measured by G2X, the suction strain HV in each shot area SA can be obtained with higher accuracy.
Further, as shown in FIG. 9, the lengths of the strain gauges G2Y and G2X are set to LY and LX, the lengths of the shot areas SA in the Y direction and the X direction are set to SY and SX, and the strain gauges G2Y and G2X are respectively measured. The lengths εY and εX in the Y direction and X direction of the shot area SA are obtained by the following equations, where εy and εx are respectively set.
εY = εy · (SY / LY) (1)
εX = εx · (SX / LX) (2)
Therefore, for each shot area SA, the lengths εY and εX in the Y direction and X direction of the shot area SA are converted into the measurement results εy and εx of the strain gauges G2Y and G2X using the equations (1) and (2). By adding εY obtained in the shot area SA arranged in the Y direction and adding εX obtained in the shot area SA arranged in the X direction, the overall distortion generated in the wafer W can be reduced. Can be sought.

(Display process)
By appropriately displaying the results measured by the strain gauges G and G2 described above, it is possible to explicitly visualize the deformation or the like occurring on the wafer W.
For example, a display device (not shown) attached to the exposure apparatus 1 with respect to the deformation information shown in FIG. 7 or an arithmetic device (for example, the main control shown in FIG. 1) that calculates and analyzes the measurement results of the strain gauges G and G2. It is good also as a structure displayed in unit 30).

  Further, as other displays, information (deformation etc.) relating to deformation for each shot area SA, overall distortion produced in the wafer W, etc. can be displayed. As a display method, a method for displaying the deformation size as a vector and displaying an arrow for each direction in the Y direction and the X direction, and a method for displaying both the design value and the deformation time for the size of the shot area SA. Etc. can be selected. In this case, it is preferable from the viewpoint of improving visibility that the display colors are different between the Y direction and the X direction, or that lighting and blinking patterns are used. In addition, with regard to the overall distortion and distortion for each shot area SA, the allowable range can be set by changing the display method (display color, lighting, and blinking pattern) depending on whether it is within the allowable range or exceeds the allowable range. It is possible to quickly and accurately visually check the error information that has been exceeded.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the second embodiment, the strain gauges G2 are arranged one by one in each shot area SA. However, the present invention is not limited to this. For example, the strain gauges G2 are provided for each strain gauge G. Also good. In this case, with respect to the measurement result of the strain gauge G, the temperature strain HT and the adsorption strain HV can be separated with higher accuracy.

  Further, in the above embodiment, when the flexure part FL is formed at a position where the negative pressure suction force by the holding mechanism does not act and the suction holding by the lift pin is not performed, the recess 42 is provided to remove the Z leveling stage 4. In the case where the flexure portion FL is formed at a position where the negative pressure suction force by the holding mechanism or the suction holding by the lift pin is made, for example, as shown in FIG. The substrate B (wafer W) may have a configuration in which a contact portion with the Z leveling stage 4 is provided at a position where the flexure portion FL is provided, and a concave portion 42 is provided between the contact portion and the flexure portion FL.

  In this case, as a method of manufacturing the flexure portion FL, for example, a method of bonding a first plate member having a thickness of the contact portion and a second plate member separately formed with the flexure portion FL, or a substrate B After forming a recess by etching or the like at a depth that leaves a contact portion at a position corresponding to the flexure portion FL, a resist having a thickness of the recess 42 is applied, and the flexure portion FL is applied on the resist using a photolithography technique. For example, a method of removing the resist after the layers are formed can be employed. In this case, it is preferable that the flexure portion FL and the connection portion 43 are formed of metal in order to maintain the strength of the connection portion 43. In this case, the strain gauge G2 is disposed on the flexure portion FL via an insulating film or the like. Set up.

  In the above embodiment, the strain gauges GY and GX are arranged in each shot area SA of the measurement wafer WA. However, the present invention is not limited to this, and depending on the required accuracy, only one direction is provided. Alternatively, a strain gauge capable of measuring the deformation may be disposed, and conversely, a strain gauge capable of measuring the deformation in three or more directions may be provided.

In the above embodiment, the same number of strain gauges G is arranged in each shot area SA. However, the present invention is not limited to this. For example, it is located on the outer peripheral side where the amount of deformation (such as the amount of thermal expansion) tends to increase. The shot area SA may have a configuration in which more strain gauges G are arranged than the shot area SA located on the inner peripheral side.
In the above embodiment, nine strain gauges GY and GX are provided in each shot area SA so that the strain distribution state can be obtained for one shot area. Thereby, it is possible to obtain the degree of higher-order deformation of the shot area SA. However, the present invention is not limited to this, and one strain gauge GY, GX may be provided.

Further, in the above embodiment, the exposure apparatus 1 is configured to measure information related to deformation using the measurement wafer WA. However, in addition to the exposure apparatus 1, the exposure apparatus 1 is connected to the exposure apparatus 1 and is sensitive to the wafer W. It is also possible to adopt a configuration in which information relating to deformation is measured in a coater / developer apparatus that performs the coating process of the agent and performs the development process on the wafer W that has been exposed.
In this case, by performing application processing and development processing on the measurement wafer WA and measuring information on deformation generated in the measurement wafer WA, the deformation that will occur in the wafer W in the application processing and development processing is predicted. Thus, it is possible to reflect the correction in the exposure process, and it is possible to manufacture a high-quality device by correcting the position where the pattern image is formed with higher accuracy.

  The wafer W in each of the above embodiments is not only a semiconductor wafer for manufacturing a semiconductor device, but also a glass substrate for a display device, a ceramic wafer for a thin film magnetic head, or an original mask or reticle used in an exposure apparatus. (Synthetic quartz, silicon wafer) or the like is applied.

  The exposure apparatus main body 1 includes a reticle R and a wafer W, in addition to a step-and-scan type scanning exposure apparatus (scanning stepper) that scans and exposes the pattern of the reticle R by synchronously moving the reticle R and the wafer W. Can be applied to a step-and-repeat type projection exposure apparatus (stepper) in which the pattern of the reticle R is collectively exposed in a stationary state and the wafer W is sequentially moved stepwise. The present invention can also be applied to a step-and-stitch type exposure apparatus that partially transfers at least two patterns on the wafer W.

  The type of the exposure apparatus main body 1 is not limited to an exposure apparatus for manufacturing a semiconductor element that exposes a semiconductor element pattern on the wafer W, but an exposure apparatus for manufacturing a liquid crystal display element or a display, a thin film magnetic head, an imaging element ( (CCD) or an exposure apparatus for manufacturing a reticle or mask.

The light source of the exposure apparatus to which the present invention is applied includes not only KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ laser (157 nm), but also g-line (436 nm) and i-line (365 nm). ) Can be used. Further, the magnification of the projection optical system may be not only a reduction system but also an equal magnification or an enlargement system. In the above embodiment, the catadioptric projection optical system is exemplified, but the present invention is not limited to this, and the optical axis (reticle center) of the projection optical system and the center of the projection area are set at different positions. It can also be applied to a refraction type projection optical system.

  Further, the present invention is applied to a so-called immersion exposure apparatus in which a liquid is locally filled between the projection optical system and the substrate, and the substrate is exposed through the liquid. It is disclosed in the publication No. 99/49504 pamphlet. Further, in the present invention, the entire surface of the substrate to be exposed as disclosed in JP-A-6-124873, JP-A-10-303114, US Pat. No. 5,825,043 and the like is in the liquid. The present invention is also applicable to an immersion exposure apparatus that performs exposure while being immersed.

  The present invention can also be applied to a twin stage type exposure apparatus provided with a plurality of substrate stages (wafer stages). The structure and exposure operation of a twin stage type exposure apparatus are described in, for example, Japanese Patent Laid-Open Nos. 10-163099 and 10-214783 (corresponding US Pat. Nos. 6,341,007, 6,400,441, 6,549). , 269 and 6,590,634), JP 2000-505958 (corresponding US Pat. No. 5,969,441) or US Pat. No. 6,208,407. Furthermore, the present invention may be applied to the wafer stage disclosed in Japanese Patent Application No. 2004-168482 filed earlier by the present applicant.

  An exposure apparatus to which the present invention is applied assembles various subsystems including the constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. It is manufactured by. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

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. 11 is a flowchart illustrating a manufacturing example of a micro device (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micro machine, or the like).
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. 12 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), 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, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., from mother reticles to glass substrates and The present invention can also be applied to an exposure apparatus that transfers a circuit pattern to a silicon wafer or the like. Here, in an exposure apparatus using DUV (deep ultraviolet), 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. In proximity-type X-ray exposure apparatuses, electron beam exposure apparatuses, and the like, a transmissive 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. .

  DESCRIPTION OF SYMBOLS 1 ... Exposure apparatus, E ... Electrode (output part), G ... Strain gauge (deformation measurement apparatus), GY, G2Y ... Strain gauge (1st measurement part), GX, G2X ... Strain gauge (2nd measurement part), SA ... shot area (irradiation area), WA ... measurement wafer (deformation measurement substrate), WS ... wafer stage (substrate stage)

Claims (11)

A substrate section;
A deformation measuring device that is provided in each of the plurality of first regions of the substrate unit and measures information related to the deformation that occurs in each of the plurality of first regions ;
Wherein provided in each of the plurality of first regions, information about the deformation occurring in each of the plurality of first regions I by the changes in temperature, the deformation measuring device a second modified measuring device for measuring independently of the And
The deformation measurement device and the second deformation measurement device are deformation measurement substrates formed through an exposure process .   A substrate section;
  A deformation measuring device that is provided in each of the plurality of first regions of the substrate unit and measures information related to deformation that occurs in each of the plurality of first regions;
  A second deformation measuring device that is disposed in a second region outside the plurality of first regions and measures information relating to deformation that occurs in the second region due to a change in temperature;
  The deformation measurement device and the second deformation measurement device are deformation measurement substrates formed on the substrate portion through an exposure process. The second deformation measuring device includes a flexure unit in which strain in a direction parallel to the surface of the substrate is transmitted from the substrate body, and transmission of strain in a direction intersecting the parallel direction from the substrate body is suppressed. deformation measurement substrate according to claim 1 or 2, wherein provided. 4. The deformation measurement substrate according to claim 1, wherein the plurality of first regions are provided corresponding to a plurality of shot regions on a device manufacturing substrate. 5. The deformation measurement device and the second deformation measurement device include a first measurement unit that measures information related to deformation in a first direction, and a second measurement unit that measures information related to deformation in a second direction different from the first direction. The deformation measurement substrate according to any one of claims 1 to 4 , wherein   The deformation | transformation as described in any one of Claim 1 to 4 which is connected to the said deformation | transformation measurement apparatus and the said 2nd deformation | transformation measurement apparatus, respectively, and the output part which outputs the information regarding the said deformation | transformation is aggregated and arrange | positioned. Measurement board. An exposure apparatus having a substrate stage that holds and moves a substrate and exposes a pattern image on the substrate,
An exposure apparatus comprising: a correction device that corrects information related to a position where the pattern image is formed based on a measurement result of the deformation measurement device according to any one of claims 1 to 6 and the second deformation measurement device. An exposure method for exposing a pattern image to a substrate,
An exposure method comprising a step of measuring information related to deformation in an exposure region on the substrate using the deformation measurement device according to any one of claims 1 to 6 and the second deformation measurement device. The exposure method according to claim 8, further comprising a step of displaying information on the measured deformation in the exposure area on the substrate. Information related to deformation measured by at least one of the deformation measurement device and the second deformation measurement device is converted into information related to deformation in the exposure region in which at least one of the deformation measurement device and the second deformation measurement device is arranged. The exposure method according to claim 9 , wherein the obtained result is displayed. The device manufacturing method using the exposure method as described in any one of Claims 8 to 10 .

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