JP6873006B2 - Manufacturing method for transport equipment, lithography equipment and articles - Google Patents

Description

The present invention relates to a transfer device, a lithography device, and a method for manufacturing an article.

With the demand for further improvement of productivity in the semiconductor manufacturing field, the exposure apparatus is required to be improved in throughput. In the exposure apparatus, it is necessary to transport the reticle (original plate) on which the pattern to be transferred is formed on the substrate from the prealignment stage to the reticle stage and hold it, and the time required for this (hereinafter, referred to as “transport time”). It is possible to improve the throughput by shortening. Here, when the reticle is held on the reticle stage, the reticle must be positioned with high accuracy with respect to the reticle stage. This is because, in the exposure apparatus, the alignment accuracy between the reticle and the substrate affects the non-defective rate of the semiconductor device, and therefore, the positioning accuracy of a certain level or higher is required even when the reticle is held on the reticle stage. Therefore, in order to improve the throughput, it is necessary to transfer the reticle to the reticle stage and hold the reticle by the reticle stage with a positioning accuracy of a certain level or higher in a short time.

The transfer of the reticle is performed by using a transfer system having a transfer mechanism for holding and transporting the reticle and a detection unit including a photodetector and an image processing unit. The detection unit detects the alignment mark provided on the reticle with a photodetector to acquire an image, and processes the image with the image processing unit to obtain the position of the reticle (alignment mark). In the transportation of the reticle, the reticle is transported onto the reticle stage by using a transport mechanism, and the position of the reticle is determined by using the detection unit in a state where the reticle is positioned on the reticle stage. Then, when the position of the reticle with respect to the position of the reticle stage is within a predetermined range, the reticle is passed from the transport mechanism to the reticle stage.

When transporting the reticle, vibration of the transport mechanism becomes a problem. In recent years, since the drive speed of the transport mechanism (the transport speed of the reticle) has been increasing for the purpose of shortening the transport time, the vibration immediately after the transport mechanism is stopped tends to be difficult to settle. If the transport mechanism is vibrating, the image (alignment mark) acquired by the detection unit will be blurred and the position of the reticle cannot be determined. Therefore, it is necessary to wait until the vibration of the transport mechanism subsides. It will lead to an increase. Therefore, a technique for suppressing the influence of vibration of the transport mechanism has been proposed (see Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 10-270349 Japanese Unexamined Patent Publication No. 2009-210489

Patent Document 1 discloses a technique in which a position sensor is provided in a transport mechanism that holds and transports a reticle, and the output of the position sensor is fed back to the transport mechanism to suppress vibration of the transport mechanism. However, in the technique disclosed in Patent Document 1, when the mechanical rigidity of the transport mechanism is low, the control band cannot be increased, so that the effect of suppressing the vibration of the transport mechanism may be reduced. Further, since a dedicated position sensor for suppressing the vibration of the transport mechanism is required, it is disadvantageous in terms of cost and the configuration of the transport mechanism becomes complicated.

Patent Document 2 discloses a technique for measuring the vibration of an object to be measured by taking an image of the object to be measured at predetermined time intervals and comparing the time-series images acquired. By applying the technique disclosed in Patent Document 2 to a transport mechanism that holds and transports a reticle, it is possible to measure the vibration of the transport mechanism without using a position sensor. However, one imaging time (time to acquire one image) also has a finite time, and a large number of imaging times are required to measure the vibration of the transport mechanism with high accuracy. This will increase the transportation time.

The present invention has been made in view of such problems of the prior art, and an exemplary object is to provide a transport device that is advantageous in reducing the time required to transport an object to be transported to a stage.

In order to achieve the above object, the transport device as one aspect of the present invention is a transport device that transports the marked object to the stage, and is a holding unit that holds and moves the object to be transported. The image pickup unit that accumulates the electric charge corresponding to the light from the transported object held in the holding unit over the accumulation time to acquire an image including the image of the mark, and the holding unit are vibrating. In the state, a feature amount related to the width of the mark on the first image is extracted from the first image acquired by the imaging unit, and based on the feature amount, the transported object held by the holding unit is said to be the same. It is characterized by having a control unit for determining whether or not it may be placed on a stage.

Further objects or other aspects of the invention will be manifested in the preferred embodiments described below with reference to the accompanying drawings.

According to the present invention, for example, it is possible to provide a transport device that is advantageous in reducing the time required to transport the object to be transported to the stage.

It is the schematic which shows the structure of the exposure apparatus as one aspect of this invention. It is a flowchart for demonstrating transport of a reticle in this embodiment. It is a figure which shows an example of the image acquired by the image pickup unit. It is a flowchart for demonstrating S903 shown in FIG. 2 in detail. In the image shown in FIG. 3, it is a figure which shows the light amount distribution in the AA'straight line. It is a figure which shows the relationship between the time change of the position of the image of a mark, and the accumulation time of an image pickup part. It is a flowchart for demonstrating transport of a reticle in this embodiment. It is a flowchart for demonstrating S909 shown in FIG. 7 in detail. In the image shown in FIG. 3, it is a figure which shows the light amount distribution in the AA'straight line. It is a figure which shows the relationship between the time change of the position of the image of a mark, and the accumulation time of an image pickup part. It is a figure for demonstrating the process of finding the vibration center of the width of a mark. It is a figure for demonstrating the process of finding the vibration center of the width of a mark. It is a figure for demonstrating the process of finding the vibration center of the width of a mark.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same member is given the same reference number, and duplicate description is omitted.

FIG. 1 is a schematic view showing a configuration of an exposure apparatus EX as one aspect of the present invention. The exposure apparatus EX is a lithography apparatus used for manufacturing semiconductor devices and the like. The exposure apparatus EX projects a pattern of a reticle (original plate) on a substrate coated with a resist to form a pattern on the substrate. The exposure apparatus EX includes an illumination optical system (not shown) that illuminates the reticle 3 and a reticle stage 4 that holds and moves the reticle 3. Further, the exposure apparatus EX includes a projection optical system 9 that projects the pattern of the reticle 3 onto the substrate, a substrate stage (not shown) that holds and moves the substrate, a transfer device 1, and a main control unit 7. The reticle 3 is provided with marks (alignment marks) 301a and 301b. The main control unit 7 includes a CPU, a memory, and the like, and controls the entire exposure apparatus EX (operation of each unit).

The transport device 1 transports the reticle 3 as an object to be transported to the reticle stage 4. In the present embodiment, the transfer device 1 includes a transfer actuator 101, a transfer arm 102, a hand base 103, leaf springs 104a and 104b, hand pads 105a and 105b, a transfer control unit 106, and an imaging unit 2. Including. The transfer actuator 101, the transfer arm 102, the hand base 103, the leaf springs 104a and 104b, and the hand pads 105a and 105b function as holding portions that hold and move the reticle 3 as the object to be transported. The hand pads 105a and 105b are connected to, for example, a vacuum pump (not shown) or a vacuum line of factory equipment (not shown) and hold the reticle 3 by vacuum suction. The transfer control unit 106 includes a CPU, a memory, and the like, and controls the entire transfer device 1 (operation of each unit). In the present embodiment, the main control unit 7 and the transfer control unit 106 are individually configured, but the present invention is not limited to this, and the main control unit 7 and the transfer control unit 106 are integrally configured. You may. The image pickup unit 2 includes a microscope 201, an image pickup element (photodetector) 202, and an image processing unit 203.

The transport of the reticle 3 in the present embodiment will be described with reference to FIGS. 2 (a) and 2 (b). Here, in the exposure apparatus EX, a case where the reticle 3 is conveyed to the reticle stage 4 and the reticle 3 is held by the reticle stage 4 will be described. In this case, as shown in FIG. 2A, the reticle 3 is conveyed to the reticle stage 4 by the transfer device 1 in S900, the reticle 3 is held by the reticle stage 4 in S905, and the transfer device is held in S906. Evacuate 1.

FIG. 2B is a flowchart for explaining a detailed sequence of transporting the reticle 3 (S900). In S901, the reticle 3 is conveyed onto the reticle stage 4. Specifically, first, the transport device 1 attracts the reticle 3 mounted on the prealignment stage (not shown) with the hand pads 105a and 105b and holds (grasps) the reticle 3 with the hand base 103. The hand base 103 is mechanically connected to the transfer actuator 101 via the transfer arm 102. The transfer actuator 101 generates a driving force for driving the transfer arm 102 and the hand base 103 (hand pads 105a and 105b) based on a command from the transfer control unit 106. In the present embodiment, the transfer actuator 101 drives the transfer arm 102 and the hand base 103 to move the reticle 3 held by the hand base 103 onto the reticle stage 4. At this time, the vertical position of the hand base 103 is a position where the leaf springs 104a and 104b are pushed into the reticle stage 4 to such an extent that the leaf springs 104a and 104b are bent by a certain amount. The amount of deflection of the leaf springs 104a and 104b is set to, for example, about 300 μm to 400 μm, but is not limited to this, and is set according to the size and members thereof.

The reticle stage 4 includes stage pads 401a and 401b. The stage pads 401a and 401b are connected to, for example, a vacuum pump (not shown) or a vacuum line of factory equipment (not shown), and a compressed air line or a clean dry air (CDA) line. The stage pads 401a and 401b switch between the connection with the vacuum line and the connection with the compressed air line with a solenoid valve (not shown), so that the suction state in which the reticle 3 is adsorbed and the blow in which the reticle 3 is blown are blown. You can switch between states.

Immediately after moving the reticle 3 onto the reticle stage 4, the stage pads 401a and 401b are in a blow state. When the stage pads 401a and 401b are in the blow state, the reticle 3 is in a slightly raised state without contacting the stage pads 401a and 401b. This is because the hand base 103 holds the reticle 3 via the leaf springs 104a and 104b, so that the force acting on the reticle 3 in the vertical direction escapes.

In this way, the reticle 3 is located on the reticle stage 4 while being held by the hand base 103 (conveyor device 1) via the hand pads 105a and 105b, and is slightly relative to the stage pads 401a and 401b. It will be in a state of surfacing.

In S902, the reticle 3 held by the hand base 103 is imaged to acquire an image including the images of the marks 301a and 301b. Specifically, immediately after moving the reticle 3 onto the reticle stage 4, that is, in a state where the hand base 103 (holding portion) is vibrating, the reticle 3 held by the hand base 103 is captured by the imaging unit 2. An image (first image) is acquired by taking an image.

The image pickup unit 2 irradiates the reticle 3 provided with the marks 301a and 301b with light, and projects the light passing through the reticle 3 and reflecting the marks 301a and 301b onto the image pickup device 202 via the microscope 201. Imaging device 202, a charge corresponding to light passing through the reticle 3, accumulated over a period of accumulation time T _DI, the image processing unit 203 converts the image of the mark 301a and 301b (light intensity distribution) into an electric signal Transfer to. The image processing unit 203 generates an image from the electric signal transferred from the image sensor 202.

3A and 3B are diagrams showing an example of an image acquired by the imaging unit 2. FIG. 3A shows an image 601 acquired by the image pickup unit 2 in a state where the reticle 3 is stationary with respect to the microscope 201 and the image pickup element 202, that is, a state in which the hand base 103 is not vibrating. .. FIG. 3B shows an image 602 acquired by the image pickup unit 2 in a state where the reticle 3 is vibrating with respect to the microscope 201 and the image sensor 202, that is, a state in which the hand base 103 is vibrating. .. For example, when there is no standby time (delay time) between S901 and S901, the vibration of the hand base 103 remains, so that the image 602 shown in FIG. 3B is acquired. The image 602 includes a mark image non-detection region 603 in which the images of the marks 301a and 301b are not detected, and a mark image detection region 604 in which the images of the marks 301a and 301b are detected. Since the images of the marks 301a and 301b are not detected in the mark image non-detection region 603, the mark image non-detection region 603 is a region having a high amount of light. On the other hand, since the marks 301a and 301b are detected in the mark image detection area 604, the mark image detection area 604 is a region where the amount of light is low.

In S903, the transport control unit 106 determines whether or not the reticle 3 held by the hand base 103 may be placed on the reticle stage 4 based on the image acquired in S902. Details of such determination will be described with reference to FIG. FIG. 4 is a flowchart for explaining in detail the determination (S903) of whether or not the reticle 3 held by the hand base 103 may be placed on the reticle stage 4.

Referring to FIG. 4, in S903a, the transport control unit 106 obtains the vibration amplitude of the widths of the marks 301a and 301b due to the vibration of the hand base 103 from the image acquired in S902. FIG. 5 is a diagram showing the light amount distribution in the AA'straight line in the image acquired in S902, that is, the image 602 shown in FIG. 3 (b). In FIG. 5, the horizontal axis represents the position and the vertical axis represents the amount of light. Amount L _B indicates the light intensity of the mark image non-detection region 603. Amount L _B may, for example, may be set from the design value, previously acquired images in a state in which the reticle stage 4 does not hold the reticle 3, may be the average value. Further, the light quantity L _T indicates the amount of light for determining a mark image detection region 604. Amount _{L T} is expressed by the following formula (1).
_{L T = a × L B,} 0 <a <1 ··· (1)
If the coefficient a is too large, the mark image detection region 604 will be erroneously determined due to the variation in the amount of light in the mark image non-detection region 603. On the other hand, if the coefficient a is too small, a region smaller than the actual mark image detection region 604 is determined to be the mark image detection region 604. Therefore, the coefficient a should be set to a value as large as possible without erroneously determining the mark image detection region 604. For example, the coefficient a may be set based on the design information of the imaging unit 2, or may be set to an appropriate value from the actual image 602.

By thus setting the amount of light L _B and L _T, as shown in FIG. 5, the following areas amount L _T, it is possible to determine that the mark image detection region 604, in the following, the hand base 103 The width of the mark image detection area 604 at the time of vibration is referred to as _WRBM. Further, in the stationary image of the hand base 103, that is, the image 601 shown in FIG. 3A, the width (dimensions) of the marks 301a and 301b in the direction parallel to the AA'straight line is defined _{as the width WRM.} .. In this case, the vibration amplitude of the widths of the marks 301a and 301b due to the vibration of the hand base 103 obtained from the image acquired in S902 is expressed by the following equation (2), and is hereinafter referred to as the vibration amplitude detection value A _RBM .
_{A RBM = W RBM -W RM ···} (2)
In S903b, in the transport control unit 106, whether the accumulation time T _DI of the image sensor 202 is 3/4 times or more (T _DI ≧ 3/4 · T _RB ) of _{the vibration cycle T RB} of the hand base 103 (holding unit). Judge whether or not. 6 (a) to 6 (c) are diagrams showing the relationship between the time change of the positions of the images of the marks 301a and 301b in the image acquired by the image pickup unit 2 and the accumulation time of the image pickup device 202. As shown in FIG. 6 (a), marks 301a and 1 period of oscillation of 301b as a vibration period _{T RB} of the hand base 103 (holding unit), marks 301a and 301b actual vibration amplitude vibration amplitude _{A RB} of the width of the And. _{FIG. 6B shows the vibration amplitude detection value A RBM} and the vibration amplitude A _{RB when the accumulation time T DI} of the image sensor 202 and the vibration period T _RB of the hand base 103 satisfy the relationship shown in the following equation (3). Shows the relationship with. The vibration cycle _TRB can be obtained from the hardware design of the transfer device 1. Further, the accumulation time _TDI depends on the performance of the imaging unit 2, but in general, it can be freely changed in the range of 1 millisecond to 1 second or more.
T _DI ≧ 3/4 ・ T _RB・ ・ ・ (3)
_{When the accumulation time T DI} of the image sensor 202 is 3/4 times or more of the vibration cycle T _RB of the hand base 103 (satisfying the equation (3)), the process proceeds to S903c. If the accumulation time T _DI of the image sensor 202 is less than 3/4 times the vibration cycle T _RB of the hand base 103 (does not satisfy the equation (3)), the process proceeds to S903d.

_{Here, the vibration amplitude detection value A RBM} when the equation (3) is satisfied is defined as the vibration amplitude detection value A _RBM1 . In this case, as shown in FIG. 6B, the vibration amplitude detection value A _RBM1 and the vibration amplitude A _RB satisfy the relationship shown in the following equation (4).
A _RB = A _RBM1 ... (4)
_{Therefore, in S903c, the transport control unit 106 sets the vibration amplitude detection value A RBM1} , which is the width of the time change of the positions of the images of the marks 301a and 301b extracted from the image acquired in S902, as the vibration amplitude A _RB (A). _RBM1 = A _RB ).

On the other hand, FIG. 6 (c) _{shows the vibration amplitude detection value A RBM} and the vibration amplitude _{when the accumulation time T DI} of the image sensor 202 and the vibration period T _RB of the hand base 103 do not satisfy the relationship shown in the equation (3). shows the relationship between the a _{RB. Here, the vibration amplitude detection value A RBM} when the equation (3) is not satisfied is defined as the vibration amplitude detection value A _RBM2 . In this case, as shown in FIG. 6 (c), the vibration amplitude detection value A _RBM2 and the vibration amplitude A _RB have a relationship shown in the following equation (5).
A _RB > A _RBM2 ... (5)
_{Therefore, the vibration amplitude detection value A RBM2} , which is the width of the time change of the positions of the images of the marks 301a and 301b extracted from the image acquired in S902, cannot be set as the vibration amplitude A _RB . Therefore, the vibration amplitude detection value A _RBM2 It is necessary to estimate the vibration amplitude _{ARB from. Therefore, in S903d, the transport control unit 106 sets the vibration amplitude detection value A RBM2} , which is the width of the time change of the positions of the images of the marks 301a and 301b extracted from the image acquired in S902, and the predetermined coefficient b. Let the product be the vibration amplitude _ARB . The coefficient b is a value represented by the ratio of the accumulation time T _{DI to the vibration period T RB.} In this way, the vibration amplitude _ARB can be estimated by the following equation (6).
A _RB = b × A _RBM2 , b = T _RB / T _DI ... (6)
As described above, the formula (6) means _{that the value obtained by multiplying the vibration amplitude detection value A RBM2} by the ratio of the vibration period T _RB and the accumulation time T _DI is defined as the vibration amplitude A _RB .

Thus, S903b, the S903c and S903d, based on the magnitude relation between the vibration period _{T RB} and the accumulation time _{T DI,} determine the vibration amplitude _{A RB. If the accumulation time T DI} is adjusted (set) so as to satisfy the equation (3) _{, the vibration amplitude ARB} can be obtained with higher accuracy. However, if the accumulation time T _DI is extended, the reticle 3 can be obtained. The time required for transportation is also delayed. On the other hand, if the accumulation time T _DI does not satisfy the equation (3), since it is impossible to determine directly the vibration amplitude A _RB from the image, it must be estimated vibration amplitude A _RB, the reticle with respect to the reticle stage 4 The position accuracy of 3 is lowered. Therefore, the accumulation time _TDI needs to be optimized (determined) according to the time required for transporting the reticle 3 and the position accuracy of the reticle 3 required by the exposure apparatus EX.

Returning to FIG. 4, in S902e, the transport control unit 106 determines whether the vibration amplitude _{A RB} obtained in S903c or S903d is equal to or smaller than the threshold _{A T,} i.e., satisfies the relationship shown in the following equation (7) Determine if it is present.
A _RB < _AT ... (7)
The threshold _AT is set based on the permissible placement error of the reticle 3 with respect to the reticle stage 4. The permissible mounting error differs depending on the device on which the transport device 1 is mounted. For example, in the exposure apparatus EX, when correcting the mounting error of the reticle 3 with respect to the reticle stage 4, the allowable mounting error is set to such an extent that the accuracy of the correction does not affect the exposure performance.

If the relationship shown in the formula (7) is satisfied, the process proceeds to S905. On the other hand, if the relationship shown in the equation (7) is not satisfied, the process proceeds to S904, and after waiting for a certain period of time (S904), the reticle 3 held by the hand base 103 is imaged by the imaging unit 2 to obtain an image. Is acquired again (S902).

S904 shown in FIG. 2B, that is, waiting for a certain period of time will be described. As described above, the waiting for a certain period of time is performed when the relationship shown in the equation (7) is not satisfied. By going through the wait for a certain time T _W, it is possible to attenuate the vibrations of the hand base 103 (holding unit).

The fixed time _TW is set as follows, for example. S902 and the amount of time spent in S903 (execution time) when it is less than half the vibration decay time of the hand base 103, a predetermined time T _W, 0 seconds, and is set to less than half of the vibration decay time. Then, S903 may be repeated until the relationship shown in the equation (7) is satisfied. On the other hand, the execution time of S902 and S903 is the case where more than half of the vibration decay time of the hand base 103, a predetermined time T _W, is set to the vibration decay time. This is because when the execution time of S902 and S903 is long, an increase in the number of executions of S902 and S903 leads to an increase in the time required for transporting the reticle 3, so that the number of executions of S902 and S903 is minimized. In this way, by setting the predetermined time _{T W} to the vibration decay time of the hand base 103, to minimize the number of times of execution of S902 and S903, when securely to satisfy the equation (7) in the second S903 Good.

When the relationship represented by the formula (7) is satisfied in S903, the transfer of the reticle 3 in S900 is completed. Returning to FIG. 2A, the reticle 3 is held by the reticle stage 4 in S905. Specifically, the stage pads 401a and 401b are switched from the blow state to the suction state. When the reticle adsorption pressure on the stage pads 401a and 401b reaches a certain level or higher, the holding of the reticle 3 in S905 is completed.

In S906, the transport device 1 is retracted. Specifically, the hand pads 105a and 105b are opened to the atmosphere, and the holding of the reticle 3 by the hand base 103 (conveyor device 1) is released. Then, the transport device 1 is retracted from the drive range of the reticle stage 4 so that the transport device 1 and the reticle stage 4 do not interfere with each other.

As described above, in the present embodiment, the vibration amplitude is extracted from the image acquired by the imaging unit 2 in the state where the hand base 103 (conveyor device 1) is vibrating as a feature amount related to the widths of the marks 301a and 301b on the image. To do. Then, based on the vibration amplitude as such a feature amount, it is determined whether or not the reticle 3 held by the hand base 103 may be placed on the reticle stage 4. Therefore, it is possible to determine whether or not the reticle 3 may be placed on the reticle stage 4 from one image at the time of vibration without waiting until the vibration of the hand base 103 is settled. Therefore, it is advantageous to reduce the time required to transport the reticle 3 to the reticle stage 4. Further, since a dedicated position sensor for suppressing the vibration of the transfer device 1 is not required, it is advantageous in terms of cost and simplification of the configuration of the transfer device 1.

Further, when it is determined in S902 that the reticle 3 may be placed on the reticle stage 4, as shown in FIG. 7, in S909, the vibration of the widths of the marks 301a and 301b due to the vibration of the hand base 103 (holding portion). You may ask for the center. The details of the process of obtaining the vibration center having the widths of the marks 301a and 301b will be described with reference to FIG. FIG. 8 is a flowchart for explaining in detail the step (S909) of obtaining the vibration center having the widths of the marks 301a and 301b.

Referring to FIG. 8, in S909a, the transport control unit 106 obtains the vibration centers having the widths of the marks 301a and 301b due to the vibration of the hand base 103 from the image acquired in S902. FIG. 9 is a diagram showing the light amount distribution in the AA'straight line in the image acquired in S902, that is, the image 602 shown in FIG. 3 (b). In FIG. 9, the horizontal axis represents the position and the vertical axis represents the amount of light. Each of the light amount L _B and L _T, as described above, shows the amount of light for determining the amount of light and the mark image detection area 604 of the mark image non-detection region 603. As shown in FIG. 9, of the intersection of the light amount L _T and the light amount distribution (curve), the position of an intersection closer to the A and P _R1, the position of an intersection closer to A 'and P _R2. In this case, the vibration centers having the widths of the marks 301a and 301b due to the vibration of the hand base 103, which are obtained from the image acquired in S902, are represented by the following equation (8), and are hereinafter referred to as _{vibration center detection values PRBM.
P RBM = (P R1 + P} R2) / 2 ··· (8)
In S903b, in the transport control unit 106, whether the accumulation time T _DI of the image sensor 202 is 3/4 times or more (T _DI ≧ 3/4 · T _RB ) of _{the vibration cycle T RB} of the hand base 103 (holding unit). Whether or not (that is, whether or not the equation (3) is satisfied) is determined. 10 (a) to 10 (c) are diagrams showing the relationship between the time change of the positions of the images of the marks 301a and 301b in the image acquired by the image pickup unit 2 and the accumulation time of the image pickup device 202. Figure 10 (a), the mark 301a and the one period of oscillation of 301b as a vibration period _{T RB} of the hand base 103 (holding unit), marks 301a and 301b actual vibration center vibration center _{P RB} of the width of And.

_{FIG. 10B shows the vibration center detection value P RBM} and the vibration center P _{RB when the accumulation time T DI} of the image sensor 202 and the vibration cycle T _RB of the hand base 103 satisfy the relationship shown in the equation (3). Shows the relationship. _{Here, the vibration center detection value P RBM} when the equation (3) is satisfied is defined as the vibration center detection value P _RBM1 . In this case, as shown in FIG. 10 (b), the vibration center detection value _{P RBM1} the vibration center _{P RB} satisfies the relation shown in the following equation (9).
P _RB = P _RBM1 ... (9)
Accordingly, in S909c, the conveyance control unit 106, a vibration amplitude detection value _{P RBM1} the center of the width of the time change of the position of the image of the mark 301a and 301b are extracted from the obtained image in step S902 and the vibration amplitude _{P RB} (P _RBM1 = P _RB ).

On the other hand, FIG. 10 (c) _{shows the vibration center detection value PRBM} and the vibration center _{when the accumulation time T DI} of the image sensor 202 and the vibration cycle T _RB of the hand base 103 do not satisfy the relationship shown in the equation (3). shows the relationship between the P _{RB. Here, the vibration center detection value P RBM} when the equation (3) is not satisfied is defined as the vibration center detection value P _RBM2 . In this case, as shown in FIG. 10 (c), the vibration center detection value P _RBM2 and the vibration center P _RB have a relationship shown in the following equation (10).
P _RB ≠ P _RBM2 ... (10)
Therefore, it is not possible to the center of the width of the time change of the position of the image of the mark 301a and 301b are extracted from the image is the vibration center detection value _{P RBM2} obtained with the oscillation center _{P RB} in S902, the oscillation center _{P RB} Need to be estimated. Therefore, in S909d, the conveyance control unit 106, the vibration center detection value _{P RBM2,} vibration amplitude detection value _{A RBM2} and, by using the coefficients c predetermined, estimated vibration center _{P RB} by the following equation (11) To do.
P _RB = c + P _RBM2 , c = T _RB / T _DI × A _RBM2 ... (11)
As described above, it is the center of the product of the vibration amplitude detection value A _RBM2 and the coefficient c, which is the width of the time change of the positions of the images of the marks 301a and 301b, and the width of the time change of the positions of the images of the marks 301a and 301b. the sum of the vibration center detection value _{a RBM2} the oscillation center _{P RB.} The coefficient c is a value represented by the ratio of the accumulation time T _{DI to the vibration period T RB.}

S909b, the S909c and S909d, based on the magnitude relation between the vibration period _{T RB} and the accumulation time _{T DI,} obtaining the oscillation center _{P RB. If the accumulation time T DI} is adjusted (set) so as to satisfy the equation (3) _{, the vibration center PRB} can be obtained with higher accuracy. However, if the accumulation time T _DI is extended, the reticle 3 can be obtained. The time required for transportation is also delayed. On the other hand, if the accumulation time T _DI does not satisfy the equation (3), since it is impossible to determine directly the vibration center P _RB from the image, must be estimated oscillation center P _RB, the reticle with respect to the reticle stage 4 The position accuracy of 3 is lowered. Therefore, the accumulation time _TDI needs to be optimized (determined) according to the time required for transporting the reticle 3 and the position accuracy of the reticle 3 required by the exposure apparatus EX.

Further, in the step of obtaining the vibration center having the widths of the marks 301a and 301b, the center of gravity of the light intensity distribution (light intensity distribution) of the mark image detection region 604 of the image 602 shown in FIG. 3B may be used. FIG. 11A is a diagram showing the light amount distribution I (x) in the AA'straight line in the image 602 shown in FIG. 3B. In FIG. 11A, the horizontal axis indicates the position and the vertical axis indicates the amount of light. Here, a variable represented by the following equation (13) is defined as the mark light amount evaluation value _{IM (x).
I M (x) = L B} -I (x) ··· (13)
Further, a variable represented by the following equation (14) is defined as the mark light amount evaluation value integration I _{IM (x).
I IM (x) = ∫I M} (x) dx ··· (14)
FIG. 11B is a diagram showing the mark light amount evaluation value integration I _{IM (x) in the AA'straight line.} Here, the value of the mark light amount evaluation value integration I _IM (x) at A'is defined by the following equation (15).
L _MAX = I _IM (A') ・ ・ ・ (15)
Further, assuming that half the value of _{L MAX is L HRF} , the center of gravity _{PLMC of the} light amount distribution satisfies the following equation (16).
L _HRF = I _IM ( _PLMC ) ・ ・ ・ (16)
The center of gravity _{P LCM} of the thus the obtained mark 301a and 301b light quantity distribution (light intensity distribution), may be the vibration center _{P RB} of the width of marks 301a and 301b.

Further, in the step of obtaining the vibration center having the widths of the marks 301a and 301b, the light intensity distribution (light intensity distribution) of the mark image detection region 604 of the image 602 shown in FIG. 3B and the image 601 shown in FIG. 3A. You may use the degree of correlation with the light intensity distribution of the mark image of. FIG. 12 shows how to obtain the degree of correlation with the mark image 605 in the image 601 from an arbitrary point of the image 602, for example, the upper left pixel of the image 602, with respect to the image 602.

_{FIG. 13 (a) shows the mark correlation degree CM} (x) on the AA'straight line obtained by the method shown in FIG. 12 (a). Since the image 602 is an image acquired at the time of vibration, a plurality of peaks may be detected or become asymmetric at _{the mark correlation degree CM (x).} Thus, obtaining the oscillation center _{P RB} with the center of gravity of the mark correlation _C M (x).

First, using a mark correlation _C M (x), the mark correlation cumulative value _C IM (x), defined by the following equation (17).
_{C IM (x) = ∫C M} (x) dx ··· (17)
FIG. 13B is a diagram showing the mark correlation degree integrated value _CIM (x) on the AA'straight line. Here, the value of the mark correlation degree integrated value _CIM (x) in A'is defined by the following equation (18).
C _MAX = C _IM (A') ・ ・ ・ (18)
Further, assuming that half the value of _{C MAX is C HRF} , the center of gravity P _CMC of the mark correlation degree satisfies the following equation (19).
C _HRF = C _IM ( _PCMC ) ・ ・ ・ (16)
In this manner, the obtained mark correlation centroid _{P CMC} of (correlation distribution), may be the vibration center _{P RB} of the width of marks 301a and 301b.

Further, based on the vibration center P _RB of the width of marks 301a and 301b, it may control the position of the reticle stage 4 at the time of placing the reticle 3 held by the transport device 1 to the reticle stage 4. Such control may be performed by the transport control unit 106 or by the main control unit 7. Specifically, by using the vibration center P _RB obtained in S909, and generates a drive command of the reticle stage 4. Assuming that such a drive command is the reticle stage correction amount command _PRS , it is defined by, for example, the following equation (20).
P _RS = P _RB ... (20)
_{By controlling the position of the reticle stage 4 based on the vibration center PRB} in this way, the placement error (positional error) when the reticle 3 held by the transport device 1 is placed on the reticle stage 4 is reduced. can do.

The method for manufacturing an article according to the embodiment of the present invention is suitable for producing an article such as a device (semiconductor element, magnetic storage medium, liquid crystal display element, etc.). Such a manufacturing method includes a step of exposing a substrate coated with a photosensitizer (forming a pattern on the substrate) and a step of developing the exposed substrate (processing the substrate) using an exposure apparatus EX. In addition, such a manufacturing method may include other well-known steps (oxidation, film formation, vapor deposition, doping, flattening, etching, resist peeling, dicing, bonding, packaging, etc.). The method for producing an article in the present embodiment is advantageous in at least one of the performance, quality, productivity and production cost of the article as compared with the conventional method.

Although the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof. For example, the present invention is not limited to the lithography apparatus as an exposure apparatus, and can be applied to a lithography apparatus such as an imprint apparatus. Here, the imprinting apparatus brings the imprint material supplied on the substrate into contact with the mold (original plate) and applies energy for curing to the imprint material to transfer the pattern of the mold to the cured product. Form a pattern. The above-mentioned method for manufacturing an article may be performed using an imprint device.

1: Transfer device 101: Transfer actuator 102: Transfer arm 103: Hand base 104a and 104b: Leaf spring 105a and 105b: Hand pad 106: Transfer control unit 2: Imaging unit 3: Reticle 301a and 301b: Mark 4: Reticle stage

Claims (12)

It is a transport device that transports the object to be transported with the mark to the stage.
A holding unit that holds and moves the object to be transported,
An imaging unit that acquires an image including an image of the mark by accumulating charges corresponding to light from the transported object held in the holding unit over an accumulation time.
A feature amount related to the width of the mark on the first image is extracted from the first image acquired by the imaging unit while the holding unit is vibrating, and the feature amount is held in the holding unit based on the feature amount. A control unit that determines whether or not the transported object may be placed on the stage.
A transport device characterized by having. Claim 1 is characterized in that the control unit obtains the vibration amplitude of the width of the mark due to the vibration of the holding unit as the feature amount based on the time change of the position of the image of the mark in the first image. The transport device according to. The control unit
When the accumulation time of the imaging unit is 3/4 times or more of the vibration cycle of the holding unit, the width of the time change of the position of the image of the mark in the first image extracted from the first image. Is the vibration amplitude.
When the accumulation time of the imaging unit is less than 3/4 times the vibration cycle of the holding unit, the time change of the position of the image of the mark in the first image extracted from the first image is changed. The transport device according to claim 2, wherein the product of the width and a predetermined coefficient is the vibration amplitude. When the control unit determines that the object to be transported held by the holding unit may be placed on the stage, the holding unit holds the object based on the time change of the position of the image of the mark in the first image. The transport device according to any one of claims 1 to 3, wherein a vibration center having a width of the mark is obtained due to vibration of a portion. The control unit
When the accumulation time of the imaging unit is 3/4 times or more of the vibration cycle of the holding unit, the width of the time change of the position of the image of the mark in the first image extracted from the first image. With the center of the vibration center as the vibration center
When the accumulation time of the imaging unit is less than 3/4 times the vibration cycle of the holding unit, the time change of the position of the image of the mark in the first image extracted from the first image is changed. The vibration center is the sum of the product of the width and the predetermined coefficient and the center of the width of the time change of the position of the image of the mark in the first image extracted from the first image. The transport device according to claim 4. The transport device according to claim 3 or 5, wherein the predetermined coefficient includes a value represented by the ratio of the accumulation time of the imaging unit to the vibration cycle of the holding unit. The transport device according to claim 4, wherein the control unit has the center of gravity of the light intensity distribution of the mark extracted from the first image as the vibration center. The control unit includes a light intensity distribution of the mark extracted from the first image and a light intensity distribution of the mark extracted from an image acquired by the imaging unit while the holding unit is not vibrating. The transport device according to claim 4, wherein the center of gravity of the correlation degree distribution indicating the degree of correlation is set as the vibration center. The control unit controls the position of the stage when the object to be transported held by the holding unit is placed on the stage based on the vibration center of the width of the mark due to the vibration of the holding unit. The transport device according to any one of claims 4 to 8. A lithography system that forms the pattern of the original plate on the substrate.
A stage that holds and moves the original plate,
The transport device according to any one of claims 1 to 9, wherein the original plate is transported to the stage as an object to be transported.
A lithographic apparatus characterized by having. The lithography apparatus according to claim 10, further comprising a projection optical system for projecting the pattern of the original plate onto the substrate. A step of forming a pattern on a substrate using the lithography apparatus according to claim 10 or 11.
A step of processing the substrate on which the pattern is formed in the step and a step of processing the substrate.
The process of manufacturing an article from the processed substrate and
A method of manufacturing an article, which comprises having.

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