JP2005044883A - Method and device for exposure and substrate treating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for exposure by which the throughput can be improved at the time of performing multiple exposures on a plurality of substrates, and to provide a substrate treating system that can improve the productivity of a device on both aspects of the throughput and yield. <P>SOLUTION: After first exposures are successively performed on n pieces of wafers (steps 208, 308, etc.), second exposures are again successively performed on the wafers in a state where the wafers are not developed (208, 308, etc.). Since the first and second exposures can be performed by changing the exposing condition, such as the lighting condition etc., one time only when the change of the exposing condition is required between the first and second exposures (step 200), the speed regulation of the changing time of the exposing condition is not required as compared with the case where the exposing condition is changed whenever the exposure of one wafer ends. Therefore, the throughput can be improved in the case where time is required for, particularly, changing the exposing condition. In addition, in the case of performing multiple exposures of triple exposure or more, third exposure, fourth exposure, etc., can be performed similarly on the n pieces of wafers continuously from the second exposure without developing any wafer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure method, an exposure apparatus, and a substrate processing system. More specifically, the exposure method performs multiple exposure on each of n (n is an integer of 2 or more) substrates using a single exposure apparatus. The present invention also relates to an exposure apparatus suitable for carrying out the exposure method, and a substrate processing system including the exposure apparatus.
[0002]
[Prior art]
In recent years, in a lithography process for manufacturing a semiconductor element, a liquid crystal display element, and the like, along with the high integration of a semiconductor element and the like, and the enlargement of a substrate such as a wafer, a mask or a reticle (hereinafter collectively referred to as “reticle”), etc. Step-and-repeat reduction projection exposure equipment (so-called stepper) or step-and-scan scanning exposure equipment (so-called scanning stepper) improved from this stepper from the viewpoint of placing importance on throughput A type of projection exposure apparatus is mainly used.
[0003]
Recently, in order to expose a desired pattern with a high resolution and a large depth of focus, a method of performing multiple exposure such as double exposure as described in, for example, Japanese Patent Laid-Open No. 10-209039 has attracted attention. Has been. The above publication discloses an exposure method using a combination of multiple exposure and a so-called modified illumination method (for example, SHRINC: Super High Resolution by Illumination Control).
[0004]
When the double exposure method is performed by, for example, a conventional exposure apparatus, that is, an exposure apparatus that includes one wafer stage that holds and moves a wafer and one reticle stage that holds and moves a reticle, a. A first exposure (first exposure) on the wafer to be exposed; b. Exchange from reticle for first exposure to reticle for second exposure (second exposure) and reticle alignment; c. A second exposure for the wafer to be exposed; d. A processing sequence in which the exchange from the second exposure reticle to the first exposure reticle, the reticle alignment, the wafer exchange, and the wafer alignment are repeated is adopted.
[0005]
When such a processing sequence is adopted, the time required for exposure (first exposure time or second exposure time) for transferring one pattern onto one wafer is T1, and the time required for reticle replacement and reticle alignment. , T2 is the time required for wafer replacement, T4 is the wafer alignment time, and T4 is the wafer alignment time. ₁ Can be expressed as the following formula (1).
[0006]
TP ₁ = 3600 / (T1 × 2 + T2 + max (T3 + T4, T2)) (1)
[0007]
Note that max (T3 + T4, T2) means the larger of T3 + T4 and T2.
[0008]
The double exposure method employing such a processing sequence is a normal exposure throughput TP in which reticle exchange and reticle alignment are performed only once per lot. _g = 3600 / ((T2 / n) + T1 + T3 + T4) has a demerit that its throughput is extremely low. Note that n is the number of wafers in one lot.
[0009]
Here, for example, assuming that max (T3 + T4, T2) = T2 in the above equation (1), the pattern of each reticle in the order of “first reticle → second reticle” with respect to the first wafer. After the transfer, a processing sequence for transferring the pattern of the respective reticles in the order of “second reticle → first reticle” to the second wafer, that is, a sequence for changing the order of the reticles used for each wafer. Can be adopted. In such a case, the reticle exchange time can be shortened by reducing the number of reticle exchanges, and the throughput can be improved. Throughput TP when this processing sequence is adopted ₂ Is expressed by the following equation (2).
[0010]
TP ₂ = 3600 / (T1 × 2 + T2 + T3 + T4) (2)
[0011]
Here, for example, when T1 = 20 (sec), T2 = 20 (sec), and T3 + T4 = 12 (sec), the throughput TP ₂ Is TP from the above equation (2) ₂ = 50 (sheets). Therefore, even in this case, the normal exposure throughput (TP _g = 109 sheets (when calculated with the number n of one lot n = 25)), only half or less of the throughput was obtained, and sufficient cost performance could not be obtained.
[0012]
On the other hand, for normal exposure that is not double exposure, two wafer stages are prepared, and the exposure operation (time T1), wafer exchange (time T3), and wafer alignment (time T4) are performed on the two wafer stages. A concept of simultaneous processing and improving throughput has been proposed. Here, when the time for switching the wafer stage used for exposure from one stage to the other is T5, the throughput TP ₃ Can be expressed as the following equation (3).
[0013]
TP ₃ = 3600 / ((T2 / n) + T1 + T5) (3)
[0014]
Here, when T5 = 5 (sec), the throughput TP ₃ = 140 (sheets), and the throughput is dramatically improved.
[0015]
[Problems to be solved by the invention]
On the other hand, when performing double exposure using an exposure apparatus having two wafer stages as described above, reticle exchange and reticle alignment must be performed once for each wafer, and throughput TP in this case ₄ Is expressed as the following equation (4).
[0016]
TP ₄ = 3600 / (T2 + T1 × 2 + T5) (4)
[0017]
In this case, throughput TP ₄ = 55 (sheets), so there is almost no effect of using two wafer stages, and there is little merit in terms of cost performance.
[0018]
As a conventional technique for improving these, for example, from the viewpoint of shortening the reticle exchange and reticle alignment time T2, in reticle alignment of the reticle that is exchanged for the second time or later, quick reticle alignment in which the number of alignment mark measurement points is reduced. There is known a so-called double reticle holder type reticle stage which is disclosed in Japanese Patent Laid-Open No. 10-209039 and the like and can be changed by only moving the reticle stage. In the latter, two reticles can be mounted on a single stage.
[0019]
However, even if the quick reticle alignment method is adopted, the time T2 required for reticle replacement and reticle alignment has only an effect of changing from 20 (sec) to 10 (sec).
[0020]
Even when a reticle stage of the double reticle holder type is adopted, the time for exchanging the reticle can be shortened, but the illumination conditions, the numerical aperture (NA), and other exposures between the first exposure and the second exposure. When changing the conditions, there is a limitation on the switching time of the exposure conditions, and the effect of improving the throughput cannot be expected so much. In particular, in the case of a small lot (the number of wafers in one lot is small), the time for exchanging the two reticles at the time of the first reticle exchange increases the ratio of the total processing time, so that the throughput is improved. The effect of is not so great. Further, when a reticle stage of the double reticle holder type is mounted on the exposure apparatus, the disadvantage is particularly great for users who do not perform double exposure. For a user who does not perform double exposure, a double reticle holder type reticle stage is not only necessary, but the size of the apparatus is inevitably increased, resulting in an increase in cost. Therefore, the double reticle holder type reticle stage has not been actively utilized.
[0021]
Furthermore, if the illumination conditions are frequently changed during double exposure, there is a demerit that the life of each part such as a motor used for changing the illumination conditions is shortened.
[0022]
On the other hand, the target resolution line width of 0.1 μm for the next-generation exposure apparatus is difficult to realize only by means of shortening the exposure wavelength, modified illumination, phase shift reticle, and the like. Therefore, the double exposure method is changed to KrF excimer laser, ArF excimer laser, or F ₂ Realizing a resolution line width of 0.1 μmL / S or a finer resolution line width by using it in an exposure apparatus using a laser or the like as a light source will enable mass production of 1G (giga) or 4G DRAMs. There is no doubt that this is one of the leading options in the development of the intended future exposure apparatus.
[0023]
The present invention has been made under such circumstances, and a first object of the present invention is to provide an exposure method capable of improving throughput in multiple exposure on a plurality of substrates.
[0024]
A second object of the present invention is to provide an exposure apparatus capable of improving throughput in multiple exposure on a plurality of substrates.
[0025]
A third object of the present invention is to provide a substrate processing system capable of improving device productivity in terms of both throughput and yield.
[0026]
[Means for Solving the Problems]
The invention according to claim 1 is an exposure method for performing multiple exposure on each of n (n is an integer of 2 or more) substrates using a single exposure apparatus (10), A first step of sequentially performing a first exposure on the substrate (Wi); and after the first step, the first substrate to the n-th substrate are not developed without developing any of the substrates. A second step of sequentially performing a second exposure, wherein the exposure apparatus has two substrate stages on which substrates are placed, and the first exposure and the second exposure for the n substrates are: Both exposure methods are performed alternately and continuously on the different substrate stages.
[0027]
According to this, 1st exposure is sequentially performed with respect to n board | substrates (1st process). Thereafter, the second exposure is sequentially performed from the first substrate to the n-th substrate without developing any of the substrates (second step). For this reason, for example, when it is necessary to change the illumination condition and other exposure conditions between the first exposure and the second exposure, the exposure condition needs to be changed only once, so that the exposure of one substrate is completed. Unlike the case where the exposure condition is changed every time, there is no restriction on the switching time of the exposure condition. Accordingly, the throughput can be improved particularly when it takes time to change the exposure conditions performed between the first exposure and the second exposure. Further, since the first exposure and the second exposure are alternately and continuously performed on two different substrate stages, for example, while the substrate is being exposed on one substrate stage, the other substrate stage Since preparatory operations such as substrate replacement and alignment can be performed (parallel processing operation), the throughput can be improved. Here, when performing multiple exposures of triple exposure or more, the third exposure, the fourth exposure,... Are performed on the n substrates without developing any of the substrates following the second exposure. ... is performed in the same manner as described above.
[0028]
In this case, it is possible to use the same pattern for the first exposure and the second exposure. However, in the first exposure in the first step, as in the exposure method according to claim 2, the n exposures are performed. The first pattern is transferred to the substrate, and in the second exposure in the second step, a second pattern different from the first pattern is transferred onto the transfer area of the first pattern on each substrate. Is desirable. In such a case, it is necessary to switch (or replace) the pattern between the first exposure and the second exposure on the substrate. However, since the pattern needs to be switched only once, the exposure of one substrate is completed. The effect of improving the throughput is expected more than when the pattern is switched each time.
[0029]
In each of the exposure methods according to claims 1 and 2, a third step of changing exposure conditions between the first step and the second step as in the exposure method according to claim 3, further comprising: Can be included.
[0030]
The invention according to claim 4 uses the two substrate stages (WST1, WST2) on which the substrates (Wi) are respectively mounted to form the patterns (RP1, RP2) on the plurality of substrates by multiple exposure, respectively. An exposure method to be formed, which is placed on the other stage in parallel with the partial exposure of the multiple exposure on the substrate placed on one of the two substrate stages. The method includes a step of exchanging a substrate in the middle of multiple exposure performed with a substrate in the middle of another multiple exposure.
[0031]
According to this, the multiple exposure placed on the other stage is performed in parallel with the partial exposure of the multiple exposure on the substrate placed on one of the two substrate stages. The substrate in the middle of is replaced with a substrate in the middle of another multiple exposure. For this reason, when the exposure on the substrate placed on one stage is completed, one stage is exposed in parallel with the partial exposure of the multiple exposure on the substrate loaded on the other stage. The substrate exchange similar to that described above is performed. Therefore, by repeating such a procedure, partial exposure of multiple exposure on the substrate is successively and sequentially performed on one stage and the other stage.
[0032]
Therefore, for example, when it is necessary to change illumination conditions and other exposure conditions (including mask exchange) between an arbitrary m-th exposure and (m + 1) -th exposure of multiple exposures, etc. Since the exposure condition only needs to be changed, the exposure condition switching time is not limited as in the case where the exposure condition is changed every time the exposure of one substrate is completed. Accordingly, the throughput can be improved particularly when, for example, it takes time to change the exposure condition performed between the m-th exposure and the (m + 1) -th exposure.
[0033]
The invention according to claim 5 is an exposure apparatus for performing multiple exposure on each of a plurality of substrates (Wi), and a buffer (47) capable of storing n (n is an integer of 2 or more) substrates. And a transport device (27, 37, 11) for transporting p (2 ≦ p ≦ n) substrates in the middle of the multiple exposure and temporarily storing them in the buffer. .
[0034]
According to this, when the m-th exposure is sequentially performed on the p substrates when the multiple exposure is performed on the plurality of substrates, the conveyance device performs the completion of the m-th exposure. Then, the exposed substrate is transported and temporarily stored in the buffer. Immediately after the exposure on the p-th substrate is completed, the p-th substrate on which the m-th exposure has been completed is stored in the buffer.
[0035]
Next, in the (m + 1) th exposure, the (m + 1) th exposure is sequentially performed on the first to pth substrates taken out from the buffer, Each time the (m + 1) th exposure is completed, the exposed substrate is transported and temporarily stored in the buffer.
[0036]
For example, when it is necessary to change illumination conditions and other exposure conditions (including mask exchange) between an arbitrary m-th exposure and (m + 1) -th exposure in multiple exposures, the exposure conditions only once Therefore, unlike the case where the exposure condition is changed each time the exposure of one substrate is completed, there is no restriction on the switching time of the exposure condition. Accordingly, the throughput can be improved particularly when, for example, it takes time to change the exposure condition performed between the m-th exposure and the (m + 1) -th exposure.
[0037]
In this case, as in the exposure apparatus according to claim 6, the multiple exposure includes a first exposure in which a first pattern (RP1) is transferred to each of the substrates, and a first exposure on the substrates. And a second exposure in which a second pattern (RP2) different from the first pattern is transferred and transferred to a pattern transfer region, the transfer device is configured so that each of the p substrates for which the first exposure has been completed. Can be temporarily stored in the buffer prior to the second exposure.
[0038]
In this case, as in the exposure apparatus according to claim 7, at least one of the number p and the storage time is set based on a time during which the performance of the photosensitive agent applied on each substrate can be maintained. Can be.
[0039]
The exposure apparatus according to any one of claims 6 and 7 includes two substrate stages (WST1 and WST2) on which the substrate is placed as in the exposure apparatus according to claim 8, with respect to the p substrates. The apparatus may further include a control device (90) that performs a process in which the first exposure and the second exposure are alternately and continuously performed on different stages.
[0040]
In this case, the control apparatus can execute a process such that the first exposure and the second exposure are performed on the same stage for each of the substrates. In such a case, since the first exposure and the second exposure on the same substrate are performed on the same stage, for example, occurrence of an overlay error between the first pattern and the second pattern due to the difference in the stage is prevented. be able to.
[0041]
In each of the exposure apparatuses according to the eighth and ninth aspects, as in the exposure apparatus according to the tenth aspect, the control device selects each of the substrates at the time of substrate alignment performed prior to the first exposure. The specific partition region and the alignment mark attached to the specific partition region can be selected at the time of substrate alignment performed prior to the second exposure.
[0042]
In each of the above-described exposure apparatuses according to claims 8 to 10, as in the exposure apparatus according to claim 11, the control device performs the first exposure on each of the plurality of partitioned regions by a scanning exposure method. When performing the above, it is possible to make the scanning direction when performing the second exposure for each partition region by the scanning exposure method coincide with that at the time of the first exposure.
[0043]
A twelfth aspect of the present invention is a substrate processing system comprising: the exposure apparatus according to any one of the fifth to eleventh aspects; and a coater / developer (33) connected inline to the exposure apparatus. is there.
[0044]
According to this, since multiple exposure of a plurality of substrates can be performed with a high throughput by the exposure apparatus, the lithography process is performed by applying the photosensitive agent to the substrate and developing the exposed substrate in the coater / developer. It is possible to perform a series of processes in (2) without touching the substrate to the outside air. Therefore, a series of processes in the lithography process can be performed with high efficiency in a state where dust and the like are prevented from being mixed, and as a result, it is possible to improve device productivity in terms of both throughput and yield.
[0045]
The invention according to claim 13 is a substrate processing system comprising an exposure apparatus (10) for performing multiple exposure on each of a plurality of substrates and a coater / developer (33) connected inline to the exposure apparatus. A buffer (47) capable of storing n (n is an integer greater than or equal to 2) substrates; and p (2 ≦ p ≦ n) substrates respectively transported during the multiple exposure, and the buffer A transfer device (27, 37, 11) for temporary storage, and the buffer includes the exposure device, an interface unit (31) for connecting the exposure device and the coater / developer, and the coater / developer The substrate processing system is provided in any one of the above.
[0046]
According to this, as described above, multiple exposure on a plurality of substrates can be performed with high throughput, and a series of processes in the lithography process can be performed with high efficiency in a state in which dust and the like are prevented from being mixed. As a result, it is possible to improve device productivity in terms of both throughput and yield. In addition, the degree of freedom in buffer arrangement is improved.
[0047]
In this case, as in the substrate processing system according to the fourteenth aspect, at least a space for storing the substrate in the buffer may be a chemical clean atmosphere.
[0048]
15. Each of the substrate processing systems according to claim 13 and claim 14, wherein the buffer has an open / close type having a lid member that can be opened and closed in a state where the inside is blocked from outside air. Buffer.
[0049]
Each substrate processing system of Claim 13-15 WHEREIN: As the substrate processing system of Claim 16, the said conveying apparatus is the same order as the order with which the said several board | substrate was conveyed from the said coater / developer. Then, it can be returned to the coater / developer.
[0050]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic plan view of a substrate processing system 200 according to the present invention.
[0051]
The substrate processing system 200 of FIG. 1 is installed in a clean room having a cleanliness class of about 100 to 1000. The substrate processing system 200 includes a coater / developer (hereinafter referred to as “C / D”) 33 arranged on the floor surface F of a clean room with a predetermined interval in the X-axis direction (left-right direction in FIG. 1). And an exposure apparatus 10, and an interface unit 31 and a wafer relay unit 49 that connect the C / D 33 and the exposure apparatus 10 in-line.
[0052]
The C / D 33 is an apparatus that applies a resist as a photosensitive agent to a wafer to be exposed and develops the exposed wafer. The C / D 33 is housed in the chamber 154, a coater (resist coating device) for applying a photosensitive agent (resist) to the wafer, a developer (developing device), a wafer transport system, and the like. (Both are not shown). The chamber 154 partially protrudes from the lower end portion (−X side) opposite to the exposure apparatus 10, and a front opening unified pod (front opening unified pod), which is a kind of wafer carrier, on the upper surface of the protruding portion. Hereinafter, a mounting table 147 for mounting a plurality of 145 (abbreviated as “FOUP”) is formed. A guide rail (not shown) extends in the Y-axis direction on the ceiling portion of the clean room facing the mounting table 147. Along the guide rail, an OHV (over head vehicle) (not shown), which is a ceiling transfer system for transferring the wafer in a state of being stored in the FOUP 145, moves. The FOUP 145 is an open / close type container (sealed wafer cassette) for storing a plurality of wafers at a predetermined interval in the vertical direction, and is similar to a transfer container disclosed in, for example, Japanese Patent Application Laid-Open No. 8-279546. Is.
[0053]
In the present embodiment, the FOUP 145 storing wafers by OHV is carried into the mounting table 147 and unloaded from the mounting table 147 by OHV.
[0054]
The interface unit 31 includes a housing 156 and a first wafer transfer system 27 accommodated in the housing 156. The first wafer transfer system 27 includes a guide 28 and two horizontal articulated robots (scalar robots) 29A and 29B that move in the X-axis direction along the guide 28.
[0055]
The scalar robots 29A and 29B constituting the first wafer transfer system 27 are not controlled by a main control device 90 (see FIG. 2) via a driving device (not shown), and a C / D side control device (not shown). Is controlled by. The scalar robots 29A and 29B transfer the wafer from the C / D 33 to the wafer relay unit 49 located on the + X side (the right side in FIG. 1) of the interface unit 31, and from the wafer relay unit 49 to the C / D 33. The wafer is transferred. The transfer path from C / D 33 to wafer relay unit 49 is shown as transfer path C0 in FIG. 5A, and the transfer path from wafer relay unit 49 to C / D 33 is transfer path C7 in FIG. 5B. It is shown in
[0056]
Returning to FIG. 1, the wafer relay portion 49 includes a chamber 61 and a second wafer transfer system 37 disposed in the chamber 61.
[0057]
A FOUP expansion housing 141 is integrally attached to the chamber 61. The FOUP expansion housing 141 is provided with a FOUP expansion port (not shown) on the side surface in the −X direction. The operator can install and take out the FOUP 47 transported using a PGV (manual transport vehicle) or the like in the FOUP expansion port.
[0058]
In order to take out the wafer from the FOUP 47, the front surface of the FOUP 47 (the surface on the side where the door (not shown) is provided) is pressed against the surface provided with the opening of the chamber 61, and the door is passed through the opening. Need to open and close. Therefore, although not shown in the present embodiment, a door opening / closing mechanism (opener) of the FOUP 47 is disposed in the + X side portion of the chamber 61. Normally, the opening of the chamber 61 is closed by an opening / closing member that constitutes an opening / closing mechanism, and the interior of the chamber 61 is isolated from the outside air. Then, by opening the door of the FOUP 47 with an opening / closing member while the front surface of the FOUP 47 is pressed against the chamber 61, the door can be opened while the inside of the FOUP 47 is blocked from the outside air. That is, the cleanliness of the interior of the FOUP 47 is originally set to about class 1, and the interior of the chamber 61 is also set to the same degree of cleanliness. Therefore, the cleanliness of the interior of the FOUP 47 is reduced by opening the door. There is no configuration. It is also possible to maintain the inside of the FOUP 47 in a chemically clean state by filling the inside of the FOUP 47 with an inert gas such as a rare gas such as nitrogen or helium and making the inside of the chamber 61 a similar inert gas atmosphere. Is possible.
[0059]
The second wafer transfer system 37 includes a first wafer mounting portion 41 disposed on the + X side of the guide 28 in the chamber 61 and a horizontal multi-joint disposed on the −Y side of the first wafer mounting portion 41. A robot (scalar robot) 43 and a second wafer placement unit 45 disposed on the −Y side of the scalar robot 43 are provided.
[0060]
The first wafer mounting unit 41 includes a table having a substantially square shape in plan view (viewed from above), and a support mechanism including three pins provided on the upper surface of the table. The wafer can be supported substantially horizontally by the upper end surfaces of the three pins constituting the support mechanism.
[0061]
The second wafer mounting unit 45 includes a table having a rectangular shape in plan view (viewed from above) and a set of support mechanisms each including three pins provided on the upper surface of the table. . The wafer can be supported substantially horizontally by the upper end surfaces of the three pins constituting each support mechanism. In this case, the three pins constituting each support mechanism may be fixed pins or vertically movable pins that can move vertically. Alternatively, the table itself may be configured to be movable up and down, and in this case, it is desirable that the table be two tables for each support mechanism.
[0062]
The second wafer transfer system 37 configured as described above has a function of mediating wafer transfer between the interface unit 31 and the exposure apparatus 10.
[0063]
That is, the wafer transferred into the chamber 61 by the scalar robot 29A (or 29B) in the interface unit 31 is placed on the support mechanism of the first wafer placement unit 41, and the scalar robot 29A (or 29B) is placed in the chamber. When retracted from 61, the arm of the scalar robot 43 transfers the wafer to one support mechanism of the second wafer mounting portion 45. The wafer transfer path when transferred in this way is shown as transfer path C1 in FIG.
[0064]
On the other hand, the wafer transferred from the exposure apparatus 10 via the later-described scalar robot 19 is placed on the first wafer from the other support mechanism of the second wafer mounting portion 45 by the arm of the scalar robot 43, contrary to the above. It is conveyed to the placement unit 41. The transport path at this time is shown as a transport path C6 in FIG.
[0065]
As shown in FIG. 1, the exposure apparatus 10 is divided into two chambers, that is, a loader chamber 152B and an exposure chamber, by a partition wall 14 disposed in the middle of the Y-axis direction and a portion slightly closer to the −Y side. The main body chamber 152 divided into 152A, the exposure apparatus main body 10A housed in the exposure chamber 152A, and the rear surface (back surface) side (+ X side) of the main body chamber 152 are arranged on the floor surface F with a predetermined interval. The light source 40 serving as the exposure light source, and a routing optical system for connecting the light source 40 to an illumination optical system (to be described later) constituting the exposure apparatus main body are provided. Since the optical system for adjusting the optical axis called a beam matching unit (BMU) is accommodated in the routing optical system, the routing optical system is hereinafter referred to as “the routing optical system BMU”. It shall be. In FIG. 1, only projection optical system PL, alignment systems ALG1 and ALG2, and wafer stages WST1 and WST2 are shown as exposure apparatus body 10A.
[0066]
Most of the wafer loader system 11 is accommodated in the loader chamber 152B. The wafer loader system 11 includes an X guide 15 extending in the X-axis direction and two Y guides 17A and 17B that are positioned above the X guide 15 (front side in FIG. 1) and extend in the Y-axis direction. It is provided as a transport guide. Each of the Y guides 17A and 17B is provided in a state of penetrating the partition wall 14.
[0067]
On the X guide 15, a horizontal articulated robot (scalar robot) 19 that is driven by a driving device (not shown) and moves along the X guide 15 is provided. Further, the Y guides 17A and 17B are respectively provided with wafer carry-in arms 24A and 24B and wafer carry-out arms 25A and 25B which are driven by a driving device (not shown) and move in the Y-axis direction along the Y guides 17A and 17B. Is provided.
[0068]
Wafer alignment devices 26A and 26B are provided in the vicinity of the + Y ends of the Y guides 17A and 17B. These wafer alignment devices 26A and 26B include a wafer edge sensor (not shown) that measures the outer peripheral edge including the notch position of the wafer, a load arm (not shown) that holds the wafer and loads it on the wafer stage, and a wafer. It includes an arm drive mechanism that rotationally drives the load arm based on the measurement result of the edge sensor and aligns the rotational position of the wafer. Hereinafter, for convenience of explanation, the wafer alignment device 26A located on the left side of FIG. 1 is referred to as “left alignment device 26A”, and the wafer alignment device 26B located on the right side of FIG. 1 is referred to as “right alignment device 26B”. ".
[0069]
The operations of the respective components of the wafer loader system 11 configured as described above are carried out by the main control device 90 (see FIG. 2) and are not shown. It is controlled by the device.
[0070]
In the wafer loader system 11, an exchange mechanism (hereinafter referred to as “loading mechanism”) for loading a wafer onto the wafer stage WST1, which will be described later, and unloading the wafer from the wafer stage WST1, by the scalar robot 19, the wafer carry-in arm 24A, the wafer carry-out arm 25A and the left alignment device 26A. , Referred to as “first wafer exchange mechanism”). In addition, an exchange mechanism (hereinafter referred to as “No. This is called a “two-wafer exchange mechanism”.
[0071]
According to the first wafer exchange mechanism, when a wafer is loaded onto the wafer stage WST1, the wafer is transported by the scalar robot 19 from the second wafer mounting unit 45 in the + X direction by a predetermined distance and is moved to that position. The wafer is transferred to the waiting wafer carry-in arm 24A. Next, the wafer is transferred by the wafer carry-in arm 24A along the Y guide 17A to the position just below the left alignment device 26A. Then, the wafer is transferred from the wafer carry-in arm 24A to a load arm (not shown) constituting the left alignment device 26A. After this delivery, the wafer carry-in arm 24A is retracted from directly below the left alignment device 26A. Then, based on the measurement result of the wafer edge sensor that constitutes the left alignment device 26A, the load arm is driven by an arm drive mechanism (not shown), and the above-described rotational positional deviation correction of the wafer is performed. Then, the wafer is loaded by the load arm on wafer stage WST1 waiting directly under left alignment device 26A. Thereafter, the load arm is separated from wafer stage WST1. The transport path at this time is shown as a transport path C2 in FIGS. 5 (A) and 5 (B).
[0072]
When the wafer is unloaded from the wafer stage WST1, the wafer on the wafer stage WST1 positioned immediately below the left alignment device 26A is unloaded by the wafer unloading arm 25A, and a predetermined distance − along the Y guide 17A. It is conveyed in the Y direction. At that position, the wafer is transferred from the wafer carry-out arm 25 </ b> A to the scalar robot 19, transported in the −X direction along the X guide 15, and placed on the second wafer placement unit 45. The transport path at this time is shown as a transport path C3 in FIGS. 5 (A) and 5 (B).
[0073]
Wafer loading and unloading on wafer stage WST2 by the second wafer exchange mechanism are performed in the same manner as wafer loading and wafer unloading by the first wafer exchange mechanism described above. The wafer transfer paths at this time are shown as transfer paths C2 ′ and C3 ′ in FIGS. 5A and 5B.
[0074]
In this embodiment, when the wafer is transferred from the C / D 33 toward the exposure apparatus 10, it is transferred along the transfer path C0 → C1 → C2 (or C2 ′) shown in FIG. When the wafer is transferred from the exposure apparatus 10 toward the C / D 33, it is transferred along the transfer path C3 (or C3 ′) → C6 → C7 shown in FIG. Further, when the wafer is transferred from the FOUP 47 toward the exposure apparatus 10, it is transferred along the transfer path C 5 → C 2 (or C 2 ′) shown in FIG. 5B, and is transferred from the exposure apparatus 10 to the FOUP 47. When the wafer is transferred toward the wafer, the wafer is transferred along a transfer path C3 (or C3 ′) → C4 shown in FIG.
[0075]
Examples of the light source 40 include a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), or F ₂ A pulsed laser light source that outputs pulsed ultraviolet light such as a laser (wavelength 157 nm) is used. A laser control device 76 (see FIG. 2) is connected to the light source 40. Control of the oscillation center wavelength and wavelength width of pulsed ultraviolet light emitted from the light source by the laser control device 76, trigger control of pulse oscillation. The gas in the laser chamber is controlled.
[0076]
In the present embodiment, the routing optical system BMU is arranged on the floor as is apparent from FIG. 1, but most of the drawing optical system BMU can be arranged below the floor below the floor surface F.
[0077]
FIG. 2 schematically shows the overall configuration of the exposure apparatus main body 10A of FIG. The exposure apparatus main body 10A is synchronously moved in a one-dimensional direction (the X-axis direction which is the horizontal direction in FIG. 2) between a reticle R as a mask and a wafer Wi (wafers W1 and W2 in this case) as a substrate. A step-and-scan scanning exposure apparatus, that is, a so-called scanning stepper, transfers a circuit pattern formed on the reticle R to each shot area on the wafer Wi through the projection optical system PL.
[0078]
This exposure apparatus main body 10A includes an illumination unit ILU, an illumination system that illuminates a reticle R as a mask from above with exposure illumination light, and a reticle R as a mask mainly in a predetermined scanning direction, here an X-axis direction (FIG. 1, a reticle driving mechanism that is driven in the horizontal direction in the drawing), a projection optical system PL that is disposed below the reticle R, a wafer that is disposed below the projection optical system PL, and has a base plate 12 serving as a stage base as a substrate. A stage apparatus 13 including wafer stages WST1 and WST2 as stages that independently hold Wi and move in a two-dimensional direction, a control system that controls these units, and the like are provided.
[0079]
The illumination unit ILU includes a beam shaping optical system 46, an energy coarse adjuster 48, a first fly-eye lens system 50, a lens 52A, a vibrating mirror 54, which are housed in a predetermined positional relationship in an illumination system housing (not shown). The lens 52B, the second fly-eye lens system 58, the illumination system aperture stop plate 42, the lens 60, the fixed reticle blind 62, the movable reticle blind 64, the relay lenses 66 and 68, and the like.
[0080]
Here, each part which comprises the illumination unit ILU is demonstrated.
[0081]
The beam shaping optical system 46 is a first fly-eye lens system that constitutes an incident end of a double fly-eye lens system, which will be described later, in which the cross-sectional shape of the ultraviolet pulse light emitted from the light source 40 is provided behind the optical path of the ultraviolet pulse light. It is shaped so as to be similar to the overall shape of the 50 incident ends, and is composed of, for example, a cylinder lens or a beam expander (both not shown).
[0082]
The energy coarse adjuster 48 is for adjusting the average energy of each pulse of the ultraviolet pulsed light. Here, a plurality of optical filters having different transmittances (1-light attenuation rates) are arranged on the rotating disk. In other words, the light attenuation rate is changed stepwise in a geometric series. The optical filter constituting the energy coarse adjuster 48 is switched by the drive mechanism 44 including a motor controlled by the illumination control device 72 under the control of the main control device 90 and the exposure amount control device 70.
[0083]
The double fly-eye lens system is for uniformizing the intensity distribution of the illumination light. The first fly-eye lens system 50 and the lens are sequentially arranged on the optical path of the ultraviolet pulse light behind the energy coarse adjuster 48. 52A and 52B, and a second fly-eye lens system 58.
[0084]
In this case, an oscillating mirror 54 for smoothing interference fringes and weak speckles generated on the irradiated surface (reticle surface or wafer surface) is disposed between the lens 52A and the lens 52B. The vibration (deflection angle) of the oscillating mirror 54 is controlled by an exposure amount controller 70 under the control of the main controller 90 via a drive system 78.
[0085]
The combination of the double fly's eye lens system and the vibrating mirror as in the present embodiment is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 1-223589 and Japanese Patent Application Laid-Open No. 7-142354.
[0086]
An illumination system aperture stop plate 42 made of a disk-like member is disposed at or near the exit-side focal plane of the second fly-eye lens system 58.
[0087]
A plurality of types (for example, six types) of aperture stops are arranged at equiangular intervals on the illumination system aperture stop plate 42 (only two aperture stops are shown in FIG. 2). The illumination system aperture stop plate 42 is rotated by a motor 74 or the like controlled by the illumination control device 72, whereby any aperture stop is selectively set on the optical path of the ultraviolet pulsed light. It has become so.
[0088]
Here, the aperture stop arranged on the illumination system aperture stop plate 42 will be briefly described. The first aperture stop is composed of a small circular aperture, and an aperture stop (small σ) for reducing the σ value as a coherence factor. An aperture stop for normal illumination (normal aperture) composed of a circular aperture is employed as the second aperture stop. As the third to fifth aperture stops, there are three types of modified aperture stops in which a plurality of openings are arranged eccentrically for modified illumination, specifically, two types of double pole stops and one type. The quadrupole aperture is adopted. Further, the sixth aperture stop is an illumination system aperture stop (annular stop) for annular illumination, and the annular ratio (ratio of the diameter of the light shielding part at the center and the outer diameter of the surrounding light transmitting part). ) Is, for example, ½. Two types of double pole stops 59A and 59B are shown in FIGS. 10A and 10D, respectively. These aperture stops 59A and 59B have a relationship (90 °) in which the positional relationship of the stops is orthogonal to each other.
[0089]
A lens 60 is disposed on the optical path of the ultraviolet pulsed light behind the illumination system aperture stop plate 42, and a fixed reticle blind 62 and a movable reticle blind 64 are disposed on the rear optical path.
[0090]
The fixed reticle blind 62 is disposed on a surface slightly defocused from the conjugate plane with respect to the pattern surface of the reticle R, and an opening having a predetermined shape that defines an illumination area IAR (see FIG. 3) on the reticle R is formed. . The opening of the fixed reticle blind has a slit-like or rectangular shape extending linearly in the Y-axis direction perpendicular to the moving direction (X-axis direction) of the reticle R during scanning exposure at the center in the circular field of the projection optical system PL. It shall be formed in the shape.
[0091]
The movable reticle blind 64 has an opening whose position and width in the direction corresponding to the scanning direction are variable, and is unnecessary by further limiting the illumination area via the movable reticle blind 64 at the start and end of scanning exposure. This prevents the exposure of important parts. The movable reticle blind 64 is controlled by the stage control device 38 under the control of the main control device 90 via the blind drive device 39.
[0092]
A relay optical system including relay lenses 66 and 68 is disposed on the optical path of the pulsed ultraviolet light behind the movable reticle blind 64.
[0093]
In the above configuration, the incident surface of the first fly-eye lens system 50, the incident surface of the second fly-eye lens system 58, the arrangement surface of the movable reticle blind 64, and the pattern surface of the reticle R are optically conjugate with each other. ing. Further, the exit-side focal plane of the first fly-eye lens system 50 (a surface light source described later is formed), and the exit-side focal plane of the second fly-eye lens system 58 (a surface light source described later is formed). ), The Fourier transform planes (exit pupil planes) of the projection optical system PL are optically conjugate with each other to form a Koehler illumination system.
[0094]
Briefly describing the operation of the illumination unit ILU configured as described above, when the ultraviolet pulse light from the light source 40 is routed and enters the illumination unit ILU via the optical system BMU (see FIG. 1), the ultraviolet pulse light is emitted. Is shaped by the beam shaping optical system 46 so as to be efficiently incident on the rear first fly-eye lens system 50. Next, the ultraviolet pulse light is adjusted to a predetermined peak intensity by the energy coarse adjuster 48 and then enters the first fly-eye lens system 50. As a result, a surface light source, that is, a secondary light source composed of a large number of light source images (point light sources) is formed on the exit-side focal plane of the first fly-eye lens system 50. Ultraviolet pulsed light that diverges from each of these many point light sources enters the second fly-eye lens system 58 via the lens 52A, the vibrating mirror 54, and the lens 52B. As a result, a surface light source (tertiary light source) is formed on the exit-side focal plane of the second fly-eye lens system 58 in which a large number of minute light source images are uniformly distributed within a region having a predetermined shape. The ultraviolet pulse light emitted from the tertiary light source passes through one of the aperture stops on the illumination system aperture stop plate 42 and then illuminates the opening of the fixed reticle blind 62 with a uniform intensity distribution. However, interference fringes and weak speckles depending on the coherence of the ultraviolet pulse light from the light source 40 can be superimposed on the intensity distribution with a contrast of about several percent. For this reason, exposure unevenness due to interference fringes and weak speckles may occur on the wafer surface, but the exposure unevenness is a reticle during scanning exposure as described in JP-A-7-142354 mentioned above. Smoothing is performed by shaking the oscillating mirror 54 in synchronization with the movement of R and the wafer and the oscillation of the ultraviolet pulse light.
[0095]
The ultraviolet pulse light passing through the opening of the fixed reticle blind 62 in this way passes through the movable reticle blind 64 and then is defined by the fixed reticle blind 62 on the reticle R as uniform illumination light through the relay lenses 66 and 68. The illumination area IAR (see FIG. 3) having a predetermined shape, here a rectangular slit shape, is illuminated. Here, the rectangular slit-shaped illumination light irradiated on the reticle R is set to extend in the Y-axis direction (non-scanning direction) at the center of the projection field of the projection optical system PL in FIG. The width in the X-axis direction (scanning direction) is set to be substantially constant.
[0096]
The reticle driving mechanism includes a reticle stage RST that can move in the XY two-dimensional direction while holding the reticle R on the reticle base board 32, a linear motor (not shown) that drives the reticle stage RST, and the position of the reticle stage RST. A reticle interferometer system for managing
[0097]
More specifically, reticle stage RST is actually levitated and supported on reticle base board 32 via a gas static pressure bearing device (not shown). Reticle stage RST is actually composed of a reticle coarse movement stage driven by a linear motor (not shown) in a predetermined stroke range in the Y-axis direction, which is the scanning direction, and a voice coil motor and the like for the reticle coarse movement stage. The reticle fine movement stage is slightly driven by the drive system in the X-axis direction, the Y-axis direction, and the θz direction (rotation direction around the Z-axis). The reticle R is attracted and held on the reticle fine movement stage via an electrostatic chuck or a vacuum chuck (not shown).
[0098]
As described above, reticle stage RST is actually composed of two stages. In the following, for convenience, reticle stage RST is driven in the X-axis and Y-axis directions by drive mechanism 30 shown in FIG. In the following description, it is assumed that the stage is a single stage that is finely driven, finely rotated in the θz direction, and scanned in the Y axis direction. The drive mechanism 30 is a mechanism using a linear motor, a voice coil motor, or the like as a drive source. However, in FIG. 2, the drive mechanism 30 is shown as a mere block for convenience of illustration and convenience of explanation.
[0099]
On the reticle stage RST, as shown in FIG. 3, a parallel plate moving mirror 34 made of the same material (for example, ceramic) as the reticle stage RST extends in the X-axis direction at one end of the Y-axis direction. A reflecting surface is formed on one surface of the movable mirror 34 in the Y-axis direction by mirror finishing. An interferometer beam from an interferometer indicated by a measurement axis BI6Y constituting the reticle interferometer system 36 of FIG. 2 is irradiated toward the reflecting surface of the movable mirror 34, and the interferometer receives the reflected light and receives the reference light. The position of reticle stage RST is measured by measuring the relative displacement with respect to the surface. Here, the interferometer having the measurement axis BI6Y actually has two interferometer optical axes that can be measured independently, and the position measurement of the reticle stage RST in the Y-axis direction and the yawing amount ( [theta] z rotation amount) can be measured. The interferometer having the length measuring axis BI6Y is based on the reticle and the Y position information of the wafer stages WST1 and WST2 from the interferometer 146 (see FIG. 4) having the length measuring axis BI2Y on the wafer stage described later. It is used to control the rotation of reticle stage RST in a direction to cancel the relative rotation (rotation error) of the wafer and to perform Y-axis direction synchronization control.
[0100]
On the other hand, a pair of corner cube mirrors 35A and 35B are installed on one side in the X-axis direction, which is the scanning direction (scanning direction) of reticle stage RST. Then, from a pair of double path interferometers (not shown) constituting the reticle interferometer system 36 of FIG. 2, the interferometer beams indicated by measurement axes BI7X and BI8X in FIG. Irradiated. Each interferometer beam is returned from the corner cube mirrors 35A and 35B to the reflecting surface on the reticle base board 32 (see FIG. 2), and the reflected light reflected there returns on the same optical path and is received by the respective double-path interferometers. Then, the relative displacement of each corner cube mirror 35A, 35B from the reference position (reflecting surface on the reticle base board 32 at the reference position) is measured. Then, the measurement values of these double path interferometers are supplied to the stage control device 38 of FIG. 2, and the position of the reticle stage RST in the X-axis direction is measured based on the average value. The information on the position in the X-axis direction is the relative position between reticle stage RST and wafer stage WST1 or WST2 based on the measured values of interferometers 16 and 18 (see FIG. 4) having wafer-side measurement axes BI1X and BI2X, which will be described later. And the synchronous control of the reticle and wafer in the scanning direction (X-axis direction) during scanning exposure based on this calculation.
[0101]
Returning to FIG. 2, as the projection optical system PL, here, both the object plane side (reticle R side) and the image plane side (wafer side) are telecentric, and reduction of 1/4 (or 1/5) reduction magnification is performed. A system is used. For this reason, when the reticle R is irradiated with the ultraviolet pulse light, the imaging light beam from the portion illuminated by the ultraviolet pulse light in the circuit pattern area on the reticle R enters the projection optical system PL, and the circuit pattern The partial inverted image is limited to a slit shape or a rectangular shape (polygonal shape) at the center of the field on the image plane side of the projection optical system PL for each pulse irradiation of ultraviolet pulsed light. As a result, the partially inverted image of the projected circuit pattern is reduced and transferred to the resist layer on the surface of one shot area of the plurality of shot areas on the wafer arranged on the imaging plane of the projection optical system PL.
[0102]
As the projection optical system PL, when an ArF excimer laser or a KrF excimer laser is used as a light source, a refraction system consisting only of a refractive optical element (lens element) is mainly used. In contrast, F ₂ When a laser or the like is used, a so-called catadioptric system (catadioptric refraction and refraction) in which a refractive optical element and a reflective optical element (such as a concave mirror or a beam splitter) are combined as disclosed in, for example, Japanese Patent Laid-Open No. 3-282527. System), or a reflective optical system consisting only of reflective optical elements. F ₂ When using a laser, a refractive optical system can be used.
[0103]
In the vicinity of the pupil plane of the projection optical system PL, N.I. A. An aperture stop is provided. The aperture size of the aperture stop is variable, and the numerical aperture (NA) of the projection optical system PL can be freely adjusted. Here, an iris diaphragm is used as the aperture stop. By changing the aperture stop aperture by a diaphragm drive mechanism (not shown), the numerical aperture N.D. A. Can be continuously changed within a predetermined range. The aperture drive mechanism is controlled by the main controller 90. The diffracted light that has passed through the aperture of the aperture stop contributes to image formation on the wafer placed in a conjugate relationship with the reticle R.
[0104]
The stage device 13 is levitated and supported on a stage surface plate 12 via a static gas bearing device (not shown), and can be moved two-dimensionally independently in the X-axis direction and the Y-axis direction. Two wafer stages WST1, WST2 And a stage drive system for driving these wafer stages WST1 and WST2, respectively.
[0105]
More specifically, a plurality of gas static pressure bearing devices (not shown) are provided on the bottom surfaces of wafer stages WST1 and WST2, and these gas static pressure bearing devices are formed on the upper surface of stage surface plate 12. For example, it is levitated and supported with a space of several microns maintained with respect to the guide surface 12a.
[0106]
On the stage surface 12, as shown in the plan view of FIG. 4, a pair of X-axis linear guides 86 and 87 extending in the X-axis direction (for example, comprising magnetic pole units incorporating permanent magnets) are provided in the Y-axis direction. Are arranged at predetermined intervals. Above these X-axis linear guides 86, 87, two sliders 82 that can move along the respective X-axis linear guides 86, 87. ₁ , 82 ₂ And 83 ₁ , 83 ₂ Are supported by levitation through a clearance of about several μm, for example, through a static gas bearing device (not shown). A total of four sliders 82 ₁ , 82 ₂ , 83 ₁ , 83 ₂ Has an inverted U-shaped cross-section that surrounds the X-axis linear guide 86 or 87 from above and from the side, and an armature coil is incorporated in each of the inside. That is, in this embodiment, the slider (armature unit) 82 in which the armature coils are respectively incorporated. ₁ , 82 ₂ And the X-axis linear guide 86 constitute moving coil type X-axis linear motors, respectively, and similarly a slider (armature unit) 83. ₁ , 83 ₂ And the X axis linear guide 87 constitute moving coil type X axis linear motors. In the following, each X-axis linear motor is replaced by a slider (armature unit) 82 which is a respective mover. ₁ , 82 ₂ , 83 ₁ , 83 ₂ X-axis linear motor 82 using the same reference numeral ₁ , 82 ₂ , 83 ₁ , 83 ₂ Shall be described.
[0107]
The four X-axis linear motors (sliders) 82 ₁ ~ 83 ₂ Of the two, that is, the X-axis linear motor 82 ₁ , 83 ₁ Is a Y-axis linear guide extending in the Y-axis direction (for example, comprising an armature unit incorporating an armature coil) 84 ₁ Are fixed to one end and the other end in the longitudinal direction. The remaining two X-axis linear motors 82 ₂ , 83 ₂ Are similar Y-axis linear guides 84 extending in the Y-axis direction. ₂ It is fixed to one end and the other end. Therefore, the Y-axis linear guide 84 ₁ , 84 ₂ Each pair of X-axis linear motors 82 ₁ , 83 ₁ , 82 ₂ , 83 ₂ Are driven along the X-axis.
[0108]
At the bottom of wafer stage WST1, a magnetic pole unit (not shown) having a permanent magnet is provided. This magnetic pole unit and one Y-axis linear guide 84 are provided. ₁ Thus, a moving magnet type Y-axis linear motor for driving wafer stage WST1 in the Y-axis direction is configured. In addition, a magnetic pole unit (not shown) having a permanent magnet is provided at the bottom of wafer stage WST2, and this magnetic pole unit and the other Y-axis linear guide 84 are provided. ₂ Thus, a moving magnet type Y-axis linear motor for driving wafer stage WST2 in the Y-axis direction is configured. In the following, for each Y-axis linear motor, the Y-axis linear guide 84 that is the respective stator. ₁ , 84 ₂ Y-axis linear motor 84 using the same reference numeral ₁ , 84 ₂ Shall be described.
[0109]
In the present embodiment, the X-axis linear motor 82 described above. ₁ , 83 ₁ And Y-axis linear motor 84 ₁ Thus, a stage drive system for XY two-dimensional driving of wafer stage WST1 is configured, and X-axis linear motor 82 is formed. ₂ , 83 ₂ And Y-axis linear motor 84 ₂ Thus, a stage drive system for driving the wafer stage WST2 in an XY two-dimensional manner independent of the wafer stage WST1 is configured. The X-axis linear motor 82 ₁ ~ 83 ₂ And Y-axis linear motor 84 ₁ , 84 ₂ Are controlled by a stage controller 38 shown in FIG.
[0110]
A pair of X-axis linear motors 82 ₁ , 83 ₁ It is possible to control yawing of wafer stage WST1 by slightly differentiating the thrust generated by each. Similarly, a pair of X-axis linear motors 82 ₂ , 83 ₂ It is possible to control yawing of wafer stage WST2 by slightly varying the thrust generated.
[0111]
On wafer stage WST1, wafer Wi (i = 1, that is, W1 in FIG. 4) is sucked and held by a wafer holder (not shown). On the upper surface of wafer stage WST1, fiducial mark plate FM1 is installed so as to be approximately the same height as wafer Wi. As shown in FIG. 4, a pair of first reference marks MK1, MK3 and a second reference mark MK2 are formed on the surface of the reference mark plate FM1 in a predetermined positional relationship.
[0112]
Further, -X side surface (left side surface in FIG. 4) 20 and + Y side surface (surface on the upper surface in FIG. 4) 21 of wafer stage WST1 are reflecting surfaces that are mirror-finished. The interferometer beam of each length measuring axis constituting the interferometer system, which will be described later, is projected onto the reflecting surface of each of the reflecting surfaces, and the reflected light is received by each interferometer, so that the reference position of each reflecting surface (generally a projection optical system) A fixed mirror is disposed on the side surface or the side surface of the alignment system, and the displacement from the fixed mirror is used as a reference surface), whereby the two-dimensional position of wafer stage WST1 is measured. Instead of the reflecting surfaces 20 and 21, an X moving mirror extending in the Y axis direction is provided near the −X end portion on the upper surface of wafer stage WST1, and a Y moving mirror extending in the X axis direction is provided near the + Y end portion. Also good.
[0113]
The configuration of the other wafer stage WST2 is the same as that of wafer stage WST1.
[0114]
That is, wafer Wi (i = 2 in FIG. 2, ie, W2) is vacuum-sucked on wafer stage WST2 via a wafer holder (not shown). Further, as shown in FIG. 4, fiducial mark plate FM2 is installed on the upper surface of wafer stage WST2 so as to be approximately the same height as wafer Wi. The first reference marks MK1, MK3 and the second reference mark MK2 are also formed on the upper surface of the reference mark plate FM2 in the same positional relationship as the reference mark plate FM1.
[0115]
Further, + X side surface (right side surface in FIG. 4) 22 and + Y side surface (surface on the upper surface in FIG. 4) 23 of wafer stage WST2 are mirror-finished reflecting surfaces. Interferometer beams of each measuring axis constituting the interferometer system described later are projected onto these reflecting surfaces, and the two-dimensional position of wafer stage WST2 is measured in the same manner as wafer stage WST1. . Instead of the reflecting surfaces 22 and 23, an X moving mirror extending in the Y axis direction may be provided near the + X end portion of the upper surface of wafer stage WST2, and a Y moving mirror extending in the X axis direction may be provided near the + Y end portion. good.
[0116]
Returning to FIG. 2, a pair of alignment systems ALG1 and ALG2 as off-axis type mark detection systems having the same function are provided on both sides of the projection optical system PL in the X-axis direction. The optical axis AX of the PL (almost coincident with the projection center of the reticle pattern image) is installed at a position separated by the same distance.
[0117]
In the present embodiment, alignment system ALG1 is used for measuring the position of an alignment mark on the wafer held on wafer stage WST1 and a reference mark formed on reference mark plate FM1. Alignment system ALG2 is used for measuring the positions of alignment marks on the wafer held on wafer stage WST2 and reference marks formed on reference mark plate FM2.
[0118]
As alignment systems ALG1 and ALG2, for example, a broadband detection light beam that does not expose the resist on the wafer is irradiated onto the target mark, and an image of the target mark formed on the light receiving surface by the reflected light from the target mark is not shown. An image processing type FIA (Field Image Alignment) type sensor that captures an image of an index using an image sensor (CCD or the like) and outputs an image signal thereof is used. In addition to the FIA system, the target mark is irradiated with coherent detection light to detect scattered light or diffracted light generated from the target mark, or two diffracted lights (for example, of the same order) generated from the target mark. Of course, it is possible to use an alignment sensor for detecting the interference by using them alone or in combination as appropriate.
[0119]
Image signals from the alignment systems ALG1 and ALG2 are A / D converted by the alignment control device 80 in FIG. 2, and the digitized waveform signal is arithmetically processed to detect the position of the mark with reference to the index center. . Information on the mark position is sent from the alignment controller 80 to the main controller 90.
[0120]
Next, the interferometer system for measuring the two-dimensional positions of wafer stages WST1 and WST2 will be described with reference to FIGS.
[0121]
As shown in FIG. 3, the reflecting surface 20 of the wafer stage WST1 is along the X axis passing through the optical axis AX of the projection optical system PL and the optical axis SXa of the alignment system ALG1 (coincidence with the index center described above). The interferometer beam indicated by the measurement axis BI1X from the X-axis interferometer 16 (see FIG. 4) is irradiated. Similarly, the reflection surface 22 of wafer stage WST2 has an X axis along the X axis passing through optical axis AX of projection optical system PL and optical axis SXb of alignment system ALG2 (coincident with the center of the index mark described above). The interferometer beam indicated by the measurement axis BI2X from the interferometer 18 (see FIG. 4) is irradiated. The X-axis interferometers 16 and 18 receive the reflected light from the reflecting surfaces 20 and 22, respectively, thereby measuring the relative displacement of each reflecting surface from the reference position, and the positions of the wafer stages WST1 and WST2 in the X-axis direction. Is to measure. Here, as shown in FIG. 3, the X-axis interferometers 16 and 18 are three-axis interferometers each having three optical axes. In addition to measurement of the wafer stages WST1 and WST2 in the X-axis direction, pitching ( Measurement of rotation about the Y axis (θy rotation) and yawing (rotation in the θz direction) is possible. The output value of each optical axis can be measured independently.
[0122]
Note that the interferometer beams of the measurement axis BI1X and the measurement axis BI2X always come into contact with the reflecting surfaces 20 and 22 throughout the moving range of the wafer stages WST1 and WST2, and accordingly, in the X-axis direction, The position of wafer stages WST1 and WST2 is managed based on the measured values of length measurement axis BI1X and length measurement axis BI2X during exposure using projection optical system PL and when alignment systems ALG1 and ALG2 are used. Is done.
[0123]
In the present embodiment, as shown in FIG. 4, a Y-axis interferometer 146 having a measurement axis BI2Y perpendicularly intersecting the measurement axes BI1X and BI2X with the optical axis AX of the projection optical system PL, and an alignment system Y-axis interferometers 144 and 148 having measurement axes BI1Y and BI3Y respectively perpendicular to the measurement axes BI1X and BI2X at the optical axes SXa and SXb of ALG1 and ALG2 are provided.
[0124]
In the case of the present embodiment, Y-axis interference having a length measuring axis BI2Y passing through the optical axis AX of the projection optical system PL is used for measuring the position in the Y-axis direction of the wafer stages WST1 and WST2 during exposure using the projection optical system PL. The Y-axis interferometer 144 having the measurement axis BI1Y passing through the optical axis SXa of the alignment system ALG1 is used for measurement of the position in the Y-axis direction of the wafer stage WST1 when using the alignment system ALG1. For measurement of the position of wafer stage WST2 in the Y-axis direction when using alignment system ALG2, the measurement value of Y-axis interferometer 148 having measurement axis BI3Y passing through optical axis SXb of alignment system ALG2 is used. Is used.
[0125]
Thus, in the present embodiment, an interferometer system that manages the XY two-dimensional coordinate positions of wafer stages WST1 and WST2 by a total of five interferometers, that is, X-axis interferometers 16 and 18 and Y-axis interferometers 144, 146, and 148. Is configured.
[0126]
As can be seen from the above description, in this embodiment, depending on the situation, the measurement axis of the Y-axis interferometer deviates from the reflection surface of wafer stages WST1 and WST2. That is, when the movement from the alignment position to the exposure position or the movement from the exposure position to the wafer exchange position, a state occurs in which the interferometer beam in the Y-axis direction does not hit the reflecting surface of wafer stages WST1 and WST2. It is essential to switch the interferometer used in In view of this point, in the present embodiment, the following measures are taken when the interferometer is reset.
[0127]
Of course, in the stage control device 38, when the interferometer beam from the Y-axis interferometer hits the reflection surface of the wafer stages WST1 and WST2 again in response to an instruction from the main control device 90, it has not been used for the control so far. The Y-axis interferometer of the measured length axis is reset (or preset), and then the movement of the wafer stages WST1, WST2 is controlled based only on the measured values of the X-axis interferometer and Y-axis interferometer constituting the interferometer system. To do.
[0128]
Note that the Y-axis interferometers 144, 146, and 148 are two-axis interferometers each having two optical axes, as apparent from FIG. 3, in addition to the measurement of the wafer stages WST1 and WST2 in the Y-axis direction. Rolling (rotation around the X axis (rotation of θx)) can be measured. In addition, the output value of each optical axis can be measured independently.
[0129]
In addition, the multi-axis interferometer described above transmits a laser beam to a reflective surface installed on a gantry (not shown) on which the projection optical system PL is placed via a reflective surface installed on the wafer table 18 with an inclination of 45 °. Irradiation may be performed to detect relative position information regarding the optical axis direction (Z-axis direction) of the projection optical system PL.
[0130]
The measurement values of the interferometers constituting the interferometer system configured as described above are sent to the stage controller 38 shown in FIG. 2 and the main controller 90 via the stage controller 38. In response to an instruction from main controller 90, stage controller 38 controls wafer stages WST1 and WST2 via the linear motors described above based on the output values of the interferometers. In other words, in this embodiment, wafer stages WST1 and WST2 are driven in the XY two-dimensional direction independently of each other and without mechanical interference.
[0131]
Further, in the present embodiment, although not shown, in order to simultaneously observe the reticle mark on the reticle R and the marks on the reference mark plates FM1 and FM2 via the projection optical system PL above the reticle R. There is provided a TTR (Through The Reticle) type reticle alignment microscope using light of the exposure wavelength. Detection signals from these reticle alignment microscopes are supplied to the main controller 90 via the alignment controller 80. Note that the configuration of the reticle alignment microscope is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-176468, and the detailed description thereof is omitted here.
[0132]
Although not shown, each of the projection optical system PL and alignment systems ALG1 and ALG2 has an autofocus / autoleveling measurement mechanism (hereinafter referred to as “AF / AL system”) for examining the in-focus position. Are provided. As described above, the configuration of the exposure apparatus in which the AF / AL system is provided in each of the projection optical system PL and the pair of alignment systems ALG1 and ALG2 is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 10-214783. Therefore, further explanation is omitted here.
[0133]
As shown in FIG. 2, the control system is centered on a main controller 90 that controls the entire apparatus as a whole, and an exposure amount controller 70 and a stage controller 38 that are subordinate to the main controller 90, and an exposure. It comprises an illumination control device 72, a laser control device 76, a transport system control device (not shown), a C / D side control device, and the like under the quantity control device 70.
[0134]
Next, with respect to the parallel processing operation (double exposure operation) for one lot of wafers at wafer stages WST1 and WST2, refer to other drawings as appropriate in accordance with FIG. I will explain.
[0135]
Note that the number n of wafers in one lot here is set based on the time during which the performance of the photosensitive agent (chemically amplified resist or the like) applied to the surface of each wafer by the coater in the C / D 33 can be maintained. . That is, the time from the application of the photosensitive agent to one wafer to the completion of development (including the transfer operation) until the development is completed is the time that can maintain the resist performance. The number n is set so as not to exceed. In the present embodiment, description will be made assuming that the number n of one lot is 25.
[0136]
In the following description, as a specific example, the case where the L / S pattern image shown in FIG. 10G is obtained using modified illumination will be described. Note that the basic principle and the like of the modified illumination used here are disclosed in Japanese Patent Laid-Open No. 4-273245 and the like, and thus the description thereof will be omitted.
[0137]
First, in the first stage, as the aperture stop, the light quantity distribution on the surface equivalent to the Fourier transform (for example, the pupil plane of the illumination optical system) or a surface in the vicinity thereof should be formed from the center of the optical axis as the pattern forming surface of the reticle. An aperture stop 59A shown in FIG. 10A has a distribution in which light is transmitted through two regions having centers at symmetrically eccentric positions in the periodic direction of the L / S pattern, and the other is a light shielding region. As the reticle, a reticle on which an L / S pattern RP1 similar to the pattern to be formed as shown in FIG. 10B is formed (hereinafter referred to as “first reticle R1” for convenience) is used. Shall be. The hatched portion in FIG. 10B shows a light-shielding portion made of chromium (Cr), and the other portions show a light transmitting portion of glass. The exposure operation performed under the above conditions will be referred to as “first exposure operation” below.
[0138]
In step 201 of FIG. 6, preparation operations such as reticle replacement (here, the reticle is not loaded on the reticle stage RST, simply loading the first reticle R1) and reticle alignment are performed. In the preparatory operation, under the instruction of the main controller 90, the illumination controller 72 of FIG. 2 performs illumination control by controlling the rotation of the motor 74 so that the aperture stop 59A is set on the optical path of the illumination light. Exposure conditions such as conditions are set.
[0139]
Next, at step 202, the first wafer W1 is loaded on wafer stage WST1.
[0140]
Prior to this, the wafer W1 is transferred from the C / D 33 along the transfer path C0 → C1 → C2, and is in a state of being held by the load arm of the left alignment device 26A. Then, in the state of FIG. 7 in which wafer stage WST1 is positioned at the left loading position immediately below left alignment device 26A, the load arm is lowered to load wafer W1 onto wafer stage WST1. Here, the position control of wafer stage WST1 is performed based on the measurement values of interferometers 16 and 144 having length measurement axes BI1X and BI1Y.
[0141]
At the left loading position, the reference mark plate FM1 of the wafer stage WST1 is positioned directly below the alignment system ALG1. For this reason, the main controller 90 resets the interferometer 144 having the measurement axis BI1Y before the alignment system ALG1 detects the reference mark MK2 on the reference mark plate FM1.
[0142]
When the reference mark MK2 is detected, an image of the mark MK2 is captured by the alignment system ALG1, and the image signal is sent to the alignment controller 80 in FIG. The alignment control device 80 performs a predetermined process on the image signal and analyzes the signal after the process to detect the position of the mark MK2 with reference to the index center of the alignment system ALG1. In the main controller 90, a coordinate system using the measurement axes BI1X and BI1Y based on the position of the mark MK2 and the measurement results of the interferometers 16 and 144 of the measurement axes BI1X and BI1Y (hereinafter referred to as “first stage as appropriate”). The coordinate position of the mark MK2 on the reference mark plate FM1 in the “coordinate system” is calculated.
[0143]
Subsequent to the wafer loading and the interferometer reset described above, in step 204 in FIG. 6, wafer alignment is performed to obtain the array of shot areas on the wafer W1 using the EGA. Specifically, wafer stage WST1 is managed based on design shot arrangement data (alignment mark position data) while managing the position of wafer stage WST1 by interferometers 16, 144 (measurement axes BI1X, BI1Y). , The alignment mark (sample mark) position of a predetermined sample shot area on the wafer W1 is measured by the alignment system ALG1, and the measurement result and the measurement values of the interferometers 16 and 144 at the time of measuring each sample mark are measured. All shot arrangement data are calculated by statistical calculation by the method of least squares based on the design coordinate data of the shot arrangement. Thereby, the coordinate position of each shot area is calculated on the first stage coordinate system. The operation of each part in the EGA is controlled by the main controller 90, and the above calculation is performed by the main controller 90.
[0144]
Then, main controller 90 calculates the relative positional relationship of each shot area with respect to mark MK2 by subtracting the coordinate position of reference mark MK2 described above from the coordinate position of each shot area.
[0145]
While wafer exchange (in this case, loading of wafer W1) and alignment operations are being performed on wafer stage WST1 side, wafer stage WST2 side is in a standby state.
[0146]
This standby wafer stage WST2 is positioned at the right loading position shown in FIG. The right loading position here is a position where the reference mark plate FM2 is positioned under the alignment system ALG2, similarly to the left loading position. Of course, the reset operation of the interferometer 148 having the measurement axis BI3Y of the interferometer system is executed prior to the detection of the mark MK2 on the reference mark plate FM2 by the alignment system ALG2.
[0147]
Next, in step 206 in FIG. 6, the wafer stage WST1 is moved from the position shown in FIG. 7 (left loading position) to the reference mark on the reference mark plate FM1 immediately below the center of the optical axis AX (projection center) of the projection optical system PL shown in FIG. Move to the position where the mark comes. Here, as can be seen from FIGS. 7 and 8, the interferometer beam of the measurement axis BI1Y is not incident on the reflecting surface 21 of the wafer stage WST1 during the movement, so that immediately after the alignment is completed, the interferometer beam of FIG. It is difficult to move wafer stage WST1 to the position. For this reason, in this embodiment, the following devices are devised.
[0148]
That is, as described above, in this embodiment, when wafer stage WST1 is at the left loading position, reference mark plate FM1 is set to be directly below alignment system ALG1, and the length measuring axis is set at this position. Since BI1Y interferometer 144 has been reset, wafer stage WST1 is temporarily returned to this position, and the distance between the detection center of alignment system ALG1 and the optical axis (projection center) of projection optical system PL, which are known in advance from that position. Based on (for convenience, BL), the wafer stage WST1 is moved to the + X side by the distance BL while monitoring the measurement value of the interferometer 16 of the measurement axis BI1X where the interferometer beam does not break. Thereby, wafer stage WST1 is moved to the position shown in FIG. It should be noted that position control in the Y-axis direction while the interferometer beam from the Y-axis interferometer does not hit wafer stage WST1 (or WST2) using a position measurement device other than the interferometer, such as a linear encoder, is performed. Is possible.
[0149]
Then, main controller 90 detects the relative positions of the projected images on the wafer surface of marks MK1, MK3 on reference mark plate FM1 and the corresponding marks on the reticle using exposure light by a pair of reticle alignment microscopes (not shown). To do.
[0150]
The main controller 90 resets the interferometer 146 of the measurement axis BI2Y prior to the above-described relative position detection (capture of the image signal of each mark image by the reticle alignment microscope). The reset operation can be executed when the next measurement axis to be used can irradiate the side surface of the wafer stage.
[0151]
As a result, the coordinate positions of the marks MK1 and MK3 on the reference mark plate FM2 in the coordinate system (second stage coordinate system) using the measurement axes BI1X and BI2Y and the projected image coordinate position of the mark on the reticle R1 on the wafer surface are determined. Detected. Then, the relative positional relationship between the exposure position (projection center of the projection optical system PL) and the coordinate positions of the marks MK1 and MK3 on the reference mark plate FM1 is obtained from the difference between the two.
[0152]
Main controller 90 finally determines the exposure position from the relative positional relationship of each shot with respect to mark MK2 on reference mark plate FM1 previously determined and the relative relationship between the exposure position and the mark MK1, MK3 coordinate positions on reference mark plate FM1. And the relative positional relationship of each shot. Depending on the result, each shot on the wafer W1 is exposed.
[0153]
As described above, the reason why high-precision alignment is possible even if the reset operation of the interferometer is performed is that the alignment mark on the reference mark plate FM1 is measured by the alignment system ALG1, and then the alignment mark of each shot area on the wafer W1. This is because the distance between the reference mark and the virtual position calculated by measuring the wafer mark is calculated by the same sensor. Since the relative positional relationship (relative distance) between the reference mark and the position to be exposed is obtained at this point, if the correspondence between the exposure position and the reference mark position is obtained by the reticle alignment microscope before exposure, the value is obtained. This is because, by adding the relative distance to the above, even if the interferometer beam of the interferometer in the Y-axis direction is cut during the movement of the wafer stage and reset again, a highly accurate exposure operation can be performed.
[0154]
Further, when the measurement axis BI1Y cannot be cut while the wafer stage WST1 moves from the alignment end position to the position shown in FIG. 8, the measurement values of the interferometers 16 and 144 of the measurement axes BI1X and BI1Y are monitored. However, it goes without saying that wafer stage WST1 may be moved linearly to the position shown in FIG. In this case, after the measurement axis BI2Y passing through the optical axis AX of the projection optical system PL is applied to the reflecting surface 21 orthogonal to the Y axis of wafer stage WST1, marks MK1, MK3 on reference mark plate FM1 by the reticle alignment microscope The interferometer resetting operation may be performed at any time before the relative position detection of the projected image on the wafer surface of the mark on the reticle corresponding thereto.
[0155]
Next, at step 208 in FIG. 6, exposure (transfer of the pattern RP1) using the pattern RP1 to the wafer W1 on the wafer stage WST1 is performed as follows.
[0156]
First, the stage controller 38 makes a relative positional relationship of each shot with respect to the mark MK2 performed as described above from the main controller 90, and the marks MK1, on the reference mark plate FM1 by a pair of reticle alignment microscopes (not shown). Wafer stage WST1 is monitored while monitoring the measured values of Y-axis interferometer 146 and X-axis interferometer 16 based on MK3 and the relative position detection result of the projected image on the wafer surface of the corresponding mark on the reticle. The wafer stage WST1 is moved to a scanning start position (acceleration start position) for exposure of the first shot of the wafer by controlling each linear motor constituting the drive system.
[0157]
Next, the stage controller 38 starts relative scanning in the X-axis direction between the first reticle R1 and the wafer W1, that is, the reticle stage RST and the wafer stage WST1, in accordance with an instruction from the main controller 90, and both stages RST, When WST1 reaches the respective target scanning speeds and reaches a constant speed synchronization state, the pattern area of reticle R1 begins to be illuminated by the ultraviolet pulse light from illumination unit ILU, and scanning exposure is started. The relative scanning is performed by the stage controller 38 while monitoring the measurement values of the measurement axes BI7X, BI8X and the measurement axis BI6Y of the Y-axis interferometer 146, the X-axis interferometer 16, and the reticle interferometer system 36 described above. This is performed by controlling the reticle drive unit 30 and each linear motor constituting the drive system of the wafer stage.
[0158]
Prior to the start of this scanning exposure, when both stages reach their respective target scanning speeds, the exposure control device 70 instructs the laser control device 76 to start pulse emission. At this time, since the movement of the predetermined blade of the movable reticle blind 64 is synchronously controlled with the movement of the reticle stage RST by the blind driving device 39 based on the instruction from the stage control device 38, the pattern region on the first reticle R1 It is the same as that of a normal scanning stepper that the irradiation of ultraviolet pulse light to the outside is prevented.
[0159]
The stage controller 38 synchronously controls the reticle stage RST and the wafer stage WST1 via each of the linear motors constituting the reticle drive unit 30 and the wafer stage drive system. At this time, particularly during the above-described scanning exposure, the movement speed Vr of the reticle stage RST in the X-axis direction and the movement speed Vw of the wafer stage WST1 in the X-axis direction are determined by the projection magnification (1/4 times or 1) of the projection optical system PL. Synchronous control is performed so that the speed ratio is maintained according to (/ 5 times).
[0160]
Then, different areas of the pattern area of the first reticle R1 are sequentially illuminated with the ultraviolet pulse light, and the illumination of the entire pattern area is completed, thereby completing the scanning exposure of the first shot on the wafer. Thereby, the pattern of the first reticle R1 is reduced and transferred to the first shot via the projection optical system PL.
[0161]
Here, simultaneously with the start of the pulse emission described above, the exposure amount control device 70 instructs the mirror drive device 78 to drive the vibrating mirror 54 so that the pattern region on the first reticle R1 is completely the illumination region IAR (FIG. 3), that is, until the image of the entire surface of the pattern is formed in the shot area on the wafer W1, the interference fringes generated in the two fly-eye lens systems 50 and 58 by performing this control continuously. To reduce unevenness.
[0162]
Further, in the blind drive device 39, based on an instruction from the stage control device 38, in order to prevent the irradiation of the ultraviolet pulse light outside the pattern region on the first reticle R1 immediately after the end of the scanning exposure, the movable reticle blind 64 The movement of the predetermined blade is synchronously controlled with the movement of the reticle stage RST.
[0163]
As described above, when the scanning exposure for the first shot is completed, the stage controller 38 controls the wafer stage WST1 through the linear motors constituting the wafer stage drive system based on an instruction from the main controller 90. It is moved stepwise in the X and Y axis directions and moved to the scanning start position (acceleration start position) for exposure of the second shot. At the time of this stepping, the stage controller 38 measures the positional displacement of the wafer stage WST1 in the X, Y, and θz directions in real time based on the measurement values of the Y axis interferometer 146 and the X axis interferometer 16. Based on this measurement result, stage control device 38 controls the position of wafer stage WST1 so that the XY position displacement of wafer stage WST1 is in a predetermined state. Further, stage control device 38 controls reticle drive unit 30 based on information on the displacement of wafer stage WST1 in the θz direction, and provides reticle stage RST (reticle fine movement stage) so as to compensate for the rotational displacement error on the wafer side. Control rotation.
[0164]
Then, in accordance with an instruction from the main controller 90, the operation of each unit is controlled by the stage controller 38 and the exposure amount controller 70 in the same manner as described above, and the same scanning exposure as described above is performed on the second shot on the wafer. Is done.
[0165]
In this way, the scanning exposure of the shot on the wafer and the stepping operation for the next shot exposure are repeated, and the pattern RP1 of the reticle R1 is sequentially transferred to all the exposure target shots on the wafer.
[0166]
The integrated exposure amount to be given to each point on the wafer during the scanning exposure is controlled by the main control device 90 via the exposure control device 70 or the stage control device 38. (Repetition frequency), at least one of pulse energy output from the light source 40, light attenuation rate of the energy coarse adjuster 48, and scanning speed of the wafer stage and the reticle stage are controlled.
[0167]
Further, in the main controller 90, for example, when correcting the movement start position (synchronization position) of the reticle stage and the wafer stage during scanning exposure, the main controller 90 instructs the stage controller 38 to correct the stage position according to the correction amount. .
[0168]
As described above, in step 208 in FIG. 6, while the wafer on wafer stage WST1 is being exposed (first exposure operation using reticle R1), on wafer stage WST2 side, in steps 302 and 304, The wafer W2 is loaded and the wafer alignment is performed at the right loading position in the same manner as the wafer stage WST1.
[0169]
In this case, the position control of wafer stage WST2 is performed based on the measurement values of interferometers 18 and 148 on measurement axes BI2X and BI3Y.
[0170]
In the exposure operation performed in parallel on the two wafer stages WST1 and WST2 and the wafer exchange / alignment operation, the wafer stage that has been completed first (wafer stage WST2 in FIG. 7) is in a waiting state, and both operations are performed. At the time when the process is completed, in steps 210 and 306, wafer stages WST1 and WST2 are moved to the positions shown in FIG.
[0171]
In wafer stage WST1 on the side where the exposure operation is completed in step 208, wafer exchange (wafer W1 → wafer W3) is performed in the left loading position in step 212, and the alignment operation is completed in step 304. In step 308, the first exposure operation is performed under the projection optical system PL for the wafer W2 on the side wafer stage WST2. At this time, the position control of wafer stage WST2 is performed based on the measurement values of interferometers 18 and 146 of measurement axes BI2X and BI2Y. Again, the interferometer 146 having the measurement axis BI2Y is reset in the same manner as described above.
[0172]
Here, in step 212, wafer W1 unloaded from wafer stage WST1 is transferred (loaded) into FOUP 47 along transfer paths C3 and C4 shown in FIG. 5A.
[0173]
Thereafter, in step 308, while the first exposure operation is performed on wafer W2 on wafer stage WST2, in the other wafer stage WST1, wafer alignment on wafer W3 is performed in step 214.
[0174]
When the exposure operation in wafer stage WST2 is completed, the movement (switching) of both wafer stages is performed in steps 216 and 310, and then the first exposure operation (step 218) on wafer W3 and the wafer in wafer stage WST2 are performed. Exchange (W2 → W4) and wafer alignment (steps 312 and 314) are performed in parallel. Also in this case, the wafer W2 unloaded from the wafer stage WST2 is transferred (loaded) into the FOUP 47 along the transfer paths C3 ′ and C4.
[0175]
Thereafter, parallel processing using two wafer stages is repeatedly performed. Then, odd-numbered wafers that have undergone the first exposure at wafer stage WST1 are loaded into FOUP 47 along transfer paths C3 and C4, and even-numbered wafers that have undergone the first exposure at wafer stage WST2 Then, it is carried into the FOUP 47 along the conveyance paths C3 ′ and C4.
[0176]
Then, the above operation is repeated, and while wafer W24 is being exposed at step 316 on wafer stage WST2, wafer W23 is replaced with wafer W25 at steps 220 and 222 on wafer stage WST1. At the same time, wafer alignment of the wafer W25 is performed.
[0177]
Further, both wafer stages are moved, that is, switched in steps 224 and 318, and when wafer stage WST2 is positioned at the right loading position, in step 320, wafer W24 is unloaded from wafer stage WST2. Thereafter, wafer stage WST2 stands by.
[0178]
On the other hand, on the wafer stage WST1 side, the first exposure operation for the last wafer W25 of one lot is performed as before. After the exposure is completed, wafer stage WST1 is moved to the left loading position in step 228, and wafer W25 is unloaded in step 230.
[0179]
As described above, when the first exposure for one lot (= 25 wafers) is completed, it is determined in the next step 400 whether or not the second exposure operation is completed. Here, since the first exposure has only been completed, the determination is denied and the process returns to step 201.
[0180]
In this step 201, a preparatory operation necessary for performing the reticle exchange and the second exposure operation is performed as follows.
[0181]
In this preparatory operation, main controller 90 instructs reticle transfer system (not shown) to start reticle exchange on reticle stage RST and start of reticle alignment, and also provides illumination conditions to illumination controller 72 in FIG. Instruct to change.
[0182]
By the way, in the first exposure operation performed so far, for example, a positive resist in which a resist image remains in a portion not exposed to light is used as the resist applied on the wafer. The pattern image P1 shown in FIG. 5 remains after development (in the present embodiment, however, development is not actually performed until the double exposure is completed). In this case, with respect to the periodic direction of the pattern RP1, exposure using the pattern RP1 (transfer of the image of the pattern RP1) can be performed with high resolution and a large focal depth, and the pattern image P1 is a good image with respect to the periodic direction. However, at both ends of the pattern image P1, as shown in FIG. 10C, there is no illumination in the vertical direction or oblique direction for resolving the pattern of this portion, so the pattern image is remarkably different. It will be deteriorated (the edge portion is bent and becomes tapered).
[0183]
Therefore, in the present embodiment, after the exposure under the two-beam interference condition by the first exposure operation described above is completed, the portion (both ends of the pattern) where the image is deteriorated by the next second exposure operation is removed, thereby removing the center. A good pattern image of the part is used effectively.
[0184]
That is, in the second exposure operation, as shown in FIG. 10D, as the aperture stop, as shown in FIG. 10D, the light quantity distribution on the plane equivalent to the Fourier transform or the plane in the vicinity thereof is the center of the optical axis. From the aperture stop 59B in such a distribution that light is transmitted through two regions having a center in a position that is symmetrically decentered in a direction orthogonal to the case of FIG. 10A, and the other is a light shielding region, As a reticle, a reticle on which a pattern RP2 composed of two isolated lines arranged at a predetermined interval in a direction orthogonal to a pattern to be formed as shown in FIG. (Referred to as “second reticle R2”) (the hatched portion in FIG. 10E is a light-shielding portion made of chromium (Cr), and the other portions are made of glass). A light-transmissive portion). In the second exposure operation, the pattern RP2 on the reticle R2 is arranged at a position where both ends of the virtual L / S pattern image that will be formed in the first exposure operation can be removed.
[0185]
Therefore, the reticle transport system (not shown) exchanges the first reticle R1 and the second reticle R2 on the reticle stage RST based on an instruction from the main controller 90, and the illumination controller 72 Based on the instruction, the exposure condition such as the illumination condition is changed by controlling the rotation of the motor 74 so that the aperture stop 59B is set on the optical path of the illumination light.
[0186]
Note that while the preparatory operation for the second exposure operation is performed as described above, the first exposure operation is finished first, and the first wafer W1 accommodated in the FOUP 47 is transferred to the FOUP 47. From the inside toward the wafer stage WST1, the transfer operation along the transfer paths C5 and C2 is started.
[0187]
When the preparation operation for the second exposure operation is completed, the wafer W1 is loaded on the wafer stage WST1 in step 202, and the wafer alignment with respect to the wafer W1 is performed in step 204. In the alignment operation performed prior to the second exposure operation, the shot region selected in the alignment operation performed prior to the first exposure operation and the same shot region and mark as the alignment mark provided in the shot region are used. Is going to be selected. The same applies to subsequent wafers.
[0188]
Then, as in the case of the first exposure operation, when wafer stage WST1 is moved directly below projection optical system PL in step 206, in next step 208, wafer W1 placed on wafer stage WST1 is applied. The second exposure operation is started. In the second exposure operation, for each wafer, the scanning direction when exposing each of the plurality of shot areas is made to coincide with the scanning direction for each shot area in the first exposure.
[0189]
On the other hand, on wafer stage WST2 side, loading of wafer W2 and wafer alignment are performed in steps 302 and 304.
[0190]
Thereafter, when exposure to all shot areas on wafer W1 is completed, switching of wafer stages WST1 and WST2 is performed in steps 210 and 306, and the second exposure operation is performed on wafer W2 on one wafer stage WST2. The other wafer stage WST1 is moved to the left loading position, and the wafer is exchanged at that position. Here, the unloaded wafer W1 is transported along the transport paths C3, C6, and C7 in FIG. 5B, is transported into the C / D 33, and is developed by the developing device (developer) in the C / D 33. Development of W1 is performed.
[0191]
After that, (i) the reticle to be used is reticle R2, (ii) the wafer to be exposed is a wafer that has been accommodated in FOUP 47 and has already completed the first exposure operation; The two wafer stages WST1, similar to the first exposure operation, except that the wafer for which the two exposure operations have been completed is transported along the transport path C3 (or C3 ′), C6, and C7 toward the C / D 33. A parallel processing operation using WST2 is performed.
[0192]
Thus, when the last wafer W25 of one lot is unloaded from the wafer stage WST1 in step 230, it is determined in step 400 whether or not the second exposure operation is completed. Then, if the determination here is affirmed, the series of processing ends.
[0193]
In the above description, the wafer load and the wafer exchange are performed after the reticle exchange / preparation operation in step 201 is completed. However, the present invention is not limited to this. Loading and wafer alignment are also desirable from the viewpoint of improving throughput.
[0194]
In this way, in the second exposure operation, when scanning exposure is performed using the second reticle R2 under the two-beam interference condition similar to that in the first exposure operation, a negative image in which a resist image remains in a portion that has been exposed to light. When a resist is used, a pattern image P1 as shown by a solid line in FIG. 10F should remain after development. However, since a positive resist is used in the present embodiment, the reticle pattern RP2 functions as a removal pattern, and as shown in FIG. 10F, at both ends of the pattern image P1 indicated by the broken line. On the other hand, as a result of the overlay exposure of the pattern image P2, an unexposed portion of the pattern image P1 is removed, and a final pattern image obtained by developing after exposure is as shown in FIG. A sharp resist pattern image of the edge portion is obtained. Although the remaining L / S is formed using a positive resist here, the remaining isolated line can be formed by the same method.
[0195]
If a negative resist is used and the same operation as the first exposure operation and the second exposure operation is performed, a penetrating L / S or a penetrating isolated line can be formed.
[0196]
Similar to the first exposure operation and the second exposure operation described above, the pattern to be formed is divided into at least two types of line patterns: a line pattern in a predetermined direction and a line pattern in a direction orthogonal thereto, Are prepared on the same or separate reticles, and the aperture stops 59A and 59B are switched by the main controller 90 via the motor 74 to superimpose the same as in the first exposure process and the second exposure process. By performing the exposure, for example, a two-dimensional lattice pattern image can be formed.
[0197]
It should be noted that the wafer at the head of the next lot may be transferred from within the C / D before the double exposure for one wafer is completed.
[0198]
The case where the exposure method described above is employed will be specifically described. That is, in the double exposure of this embodiment, after performing a first exposure operation (parallel processing operation with wafer exchange / wafer alignment) on a predetermined number of wafers, reticle exchange and reticle alignment are performed only once, and then a predetermined exposure is performed. A sequence is employed in which a second exposure operation (parallel processing operation with wafer replacement / wafer alignment) is performed on the number of wafers. For this reason, the time during which exposure is not performed is only the time required for switching between both wafer stages and the time required for preparatory operations such as reticle replacement and reticle alignment. That is, T1 is the time required for one exposure on one wafer, T5 is the time required for switching, n is one lot (predetermined number) of wafers, T2 is the time required for reticle replacement and reticle alignment, and 1 Since the time required for exposure of wafers per sheet can be expressed as (T1 + T5) × 2 + (T2 / n) × 2, throughput TP ₅ Can be expressed as the following equation (5).
[0199]
TP ₅ = 3600 / ((T1 + T5) × 2 + (T2 / n) × 2) (5)
[0200]
Here, assuming that the same values as those used in the description of the prior art described above are used for each time, T1 = 20 (sec), T2 = 20 (sec), and T5 = 5 (sec). Throughput TP from equation (5) above ₅ Is about 70 sheets. This is the case of double exposure using one wafer stage of the above-described prior art (throughput TP ₂ = 50 sheets), the throughput is improved by about 40%.
[0201]
Here, for example, when one lot (“predetermined number” in the present embodiment) is set to 25, the time required for the first exposure from the first to the 25th to be completed is as follows:
T2 + (T1 + T5) × 25
= 20 + (20 + 5) × 25 = 645 (seconds) (6)
Therefore, even if the time required for completing the second exposure (645 seconds) is combined, the time required for the total exposure is about 22 minutes.
[0202]
As a specific example, a resist used in an exposure apparatus using an ArF excimer laser as a light source can maintain its performance for several hours with a clean degree in a normal exposure apparatus. Therefore, even if the double exposure as in the present embodiment is performed, the resist hardly deteriorates during the exposure, so that there is almost no adverse effect on the device which is the final product.
[0203]
In the future, F ₂ The introduction of an exposure apparatus that uses a laser as an exposure light source is also under consideration. However, even when such an exposure apparatus is introduced, the cleanness inside the exposure apparatus is maintained for 30 minutes according to the above equation (6). If the degree of cleanliness is maintained as much as possible, even if an unexpected error occurs, double exposure similar to that of the present embodiment can be performed on one lot = 25 wafers. .
[0204]
FIG. 11 is a graph showing the results of simulating changes in throughput when the number of wafers per lot is changed in various exposure apparatuses. In FIG. 11, among the subscripts attached to each curve L, the Roman numeral (I or II) after R indicates the number of reticles that can be simultaneously placed on the reticle stage, and the Roman numeral after W. (I or II) indicates the number of wafer stages provided in the exposure apparatus. (Thus, for example, L _(RI-WII) Shows the change in the throughput of the exposure apparatus in which one reticle can be mounted on the reticle stage RST and has two wafer stages.) The curve Ln shows the change in the throughput of the exposure apparatus of this embodiment. is there.
[0205]
As can be seen from FIG. 11, in any of the exposure apparatuses, the throughput shows almost the same change, but the throughput of the exposure apparatus of this embodiment is the same type of exposure apparatus L. _(RI-WII) It can be seen that the throughput is remarkably improved as compared with.
[0206]
Further, from FIG. 11, in any apparatus, the throughput increases as the number of wafers in one lot increases, but conversely, if the number of wafers in one lot is small, which apparatus is Even if it is used, the throughput is hardly changed. That is, in order to improve the throughput, it is desirable to increase the number of wafers in one lot as much as possible. However, if one lot is hundreds or thousands (when processing DRAM or the like), there will be a situation where not all wafers can be stored in the FOUP 47, and the exposure time for each wafer will be very long. For example, when the number of chips is extremely long (when the number of chips is extremely large) or when the resist performance maintaining time is short, the upper limit of the number of lots per lot is determined according to the resist performance maintaining time.
[0207]
That is, in consideration of the time during which the resist performance that changes according to the cleanliness in the exposure apparatus can be maintained, the number of wafers that can be stored in the FOUP 47, and the like, It is desirable to maximize the throughput by setting the number of sheets as much as possible.
[0208]
As means for realizing this, for example, an input device such as a keyboard is connected to the main control device 90, and the performance maintenance time of the resist inputted by the operator via the input device is inputted in advance. Based on the number of sheets that can be stored in the FOUP 47, the main controller 90 determines the number of sheets in one lot so that the resist performance maintenance time is within the time from resist coating to development for one lot of wafers. It ’s fine. By controlling the number of sheets in one lot in this way, it is possible to perform management so as not to lower the exposure accuracy and throughput even if various conditions are changed.
[0209]
On the other hand, FIG. 12 shows the throughput when the configuration of each stage is changed for each of exposure apparatuses having different reticle stage maximum speed and acceleration and wafer stage maximum speed and acceleration when one lot is set to 25 sheets. The table shows the improvement rate of the throughput from the double exposure throughput (49 sheets) using the exposure apparatus having one wafer stage described in the prior art. Here, the configuration of each stage can be changed by changing the number of sheets that can be placed on the reticle stage at a time (1 (shown as “RI” in FIG. 12) or 2 (shown as “RII” in FIG. 12)), The number of wafer stages (one (shown as “WI” in FIG. 12) or two (shown as “WII” in FIG. 12)) is changed. Note that the case of using the sequence of the present embodiment is shown in the lowermost stage surrounded by a double line.
[0210]
FIG. 13 is a graph showing the improvement rate of the throughput of FIG.
[0211]
From these results, as shown in the graph of FIG. 13, it was found that the highest throughput was achieved by adopting double exposure in the same manner as in this embodiment in any apparatus.
[0212]
As described above in detail, according to the exposure method of this embodiment, the first exposure is sequentially performed on n wafers, and then the first wafer is not developed. To the nth wafer are sequentially subjected to the second exposure. For this reason, when it is necessary to change the illumination conditions and other exposure conditions between the first exposure and the second exposure, the exposure conditions need only be changed once. Therefore, each time the exposure of one wafer is completed. Unlike the case where the exposure conditions are changed, the exposure condition switching time is not affected. Accordingly, the throughput can be improved particularly when it takes time to change the exposure conditions performed between the first exposure and the second exposure.
[0213]
In the present embodiment, the exposure operation, the wafer exchange, and the wafer alignment are continuously performed in parallel using the double stage of wafer stages WST1 and WST2. In such a double stage, the throughput increases almost in proportion to the shortening of the exposure time, so that the effect of improving the throughput is greater than that of an exposure apparatus subject to restrictions on wafer replacement and wafer alignment time.
[0214]
In this embodiment, the number of sheets in one lot is set based on the time during which the performance of the photosensitive agent (chemically amplified resist or the like) applied on each wafer can be maintained. Even if the exposure is performed and then the second exposure is performed on the wafer on which the first exposure has been performed, the photosensitive agent is not deteriorated, so that it does not cause a decrease in the yield of the device as the final product.
[0215]
In the present embodiment, since the first exposure and the second exposure are performed on the same wafer stage on the same wafer stage, for example, the first pattern and the second pattern are overlapped due to the difference in the wafer stage. Generation of errors can be prevented.
[0216]
Further, in the present embodiment, for each wafer, the shot area selected at the time of wafer alignment performed prior to the first exposure and the alignment mark attached to the shot area are displayed on the wafer that is performed prior to the second exposure. Since the selection is also performed at the time of alignment, the wafer position measurement error due to the alignment mark shape error can be minimized.
[0217]
Further, for each wafer, since the scanning direction when the first exposure is performed by the scanning exposure method for each of the plurality of shot regions and the scanning direction when the second exposure is performed are made to coincide with each other, the transfer error is further increased. Can be performed with less exposure.
[0218]
In addition, according to the lithography system of this embodiment, multiple exposure of a plurality of wafers can be performed with a high throughput by the exposure apparatus, so that the photosensitive agent is applied to the wafer and the exposed wafer is developed in the coater / developer. As a result, a series of processes in the lithography process can be performed without exposing the wafer to the outside air. Therefore, a series of processes in the lithography process can be performed with high efficiency in a state where dust and the like are prevented from being mixed, and as a result, it is possible to improve device productivity in terms of both throughput and yield.
[0219]
The wafer storage time in the FOUP 47 is set based on the time during which the performance of the photosensitive agent (chemically amplified resist, etc.) applied on each wafer can be maintained instead of or together with the number n of one lot described above. It is also good to do.
[0220]
Further, in the exposure apparatus of the present embodiment, it is sufficient that only one reticle can be placed on the reticle stage RST. Therefore, when the user does not perform multiple exposure or uses multiple exposure and single exposure in combination. Even in such cases, the reticle stage and hence the exposure apparatus are not unnecessarily large compared to the case where a reticle stage capable of mounting a plurality of reticles is mounted, thereby reducing the cost and the footprint. be able to.
[0221]
Furthermore, in order to improve the throughput of the exposure apparatus as in the past, there is almost no deterioration in accuracy compared to the case of performing quick alignment of the reticle, etc., and it is not necessary to mount a double reticle stage, and the illumination conditions can be switched. The fact that it is not necessary to perform at high speed is also a great merit in terms of cost performance.
[0222]
In addition, it is possible to reduce wear due to friction of each part involved in the change in illumination conditions and the like, motor consumption, etc., and to reduce the occurrence of failure in each part of the exposure apparatus and to suppress the shortening of the lifetime as much as possible. Can do.
[0223]
In addition, when the reticle is exchanged at high speed for each wafer, two is the limit, and in order to exchange three reticles for each wafer at high speed, it is necessary to provide a complicated mechanism. . However, in the present invention, since the reticle may be exchanged in lot units, it is not necessary to provide a special mechanism even when triple exposure is performed, and high throughput can be obtained at low cost.
[0224]
In addition to double exposure, when multiple exposure of triple exposure or more is performed, the second exposure is followed by the third exposure, the second exposure on the n wafers without developing any wafer. Four exposures,... May be performed in the same manner as described above. Also in this case, if the number of sheets in one lot is set based on the time during which the performance of the photosensitive agent can be maintained, the same effect as described above can be obtained.
[0225]
In the above embodiment, different patterns are used for the first exposure and the second exposure, but the same pattern may be used for the first exposure and the second exposure.
[0226]
In the above embodiment, a double stage (twin stage) type exposure apparatus having two wafer stages is used. However, a single stage type exposure apparatus may be used.
[0227]
In the above-described embodiment, an exposure method using a combination of multiple exposure and a so-called modified illumination method (for example, SHRINC: Super High Resolution by Illumination Control) is used. However, the present invention is not limited to this, and a general multiple exposure method is used. It's also good.
[0228]
In addition, after performing double exposure on the wafer of one lot in the order of the first reticle → second reticle, a sequence in which the double exposure of the wafer of the next lot is performed in the order of the second reticle → first reticle is adopted. Thus, it is possible to further improve the throughput.
[0229]
In the above embodiment, the FOUP 47 is used as the buffer. However, the present invention is not limited to this, and an internal buffer provided in advance in the substrate processing system may be used. In this case, it may be provided in any of the main body chamber 152, the chamber 61 constituting the wafer relay unit 49, the housing 156 constituting the interface unit 31, and the chamber 154 constituting the C / D 33. Further, when the FOUP 47 is used, not only the interface unit 31 but also the C / D 33 or the exposure apparatus 10 may be provided.
[0230]
In the above embodiment, the case where the present invention is applied to the scanning stepper has been described. However, the present invention is not limited to this, and the present invention can also be applied to a stationary exposure apparatus such as a stepper. Further, the use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, but for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern to a square glass plate, a thin film magnetic head, a micromachine, and DNA The present invention can be widely applied to an exposure apparatus for manufacturing chips and the like. 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., glass substrates or silicon wafers, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern.
[0231]
The light source of the exposure apparatus of the above embodiment is F. ₂ Not only an ultraviolet pulse light source such as a laser light source, an ArF excimer laser light source, and a KrF excimer laser light source, it is also possible to use an ultrahigh pressure mercury lamp that emits bright lines such as g-line (wavelength 436 nm) and i-line (wavelength 365 nm). . In addition, a single-wavelength laser beam in the infrared region or visible region oscillated from a DFB semiconductor laser or fiber laser is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and ytterbium), and a nonlinear optical crystal You may use the harmonic which wavelength-converted into ultraviolet light using. The magnification of the projection optical system may be not only a reduction system but also an equal magnification or an enlargement system.
[0232]
For semiconductor devices, the step of designing the function and performance of the device, the step of manufacturing a reticle based on this design step, the step of manufacturing a wafer from a silicon material, and transferring the reticle pattern onto the wafer by the exposure apparatus of the above-described embodiment And a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like.
[0233]
【The invention's effect】
As described above in detail, according to the exposure method of the present invention, there is an effect that it is possible to improve throughput when multiple exposure is performed on a plurality of substrates.
[0234]
According to the exposure apparatus of the present invention, there is an effect that it is possible to improve the throughput when multiple exposure is performed on a plurality of substrates.
[0235]
According to the substrate processing system of the present invention, there is an effect that the productivity of devices can be improved in both throughput and yield.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a substrate processing system according to the present invention.
FIG. 2 is a view schematically showing the overall configuration of the exposure apparatus main body of FIG. 1 together with a light source.
FIG. 3 is a perspective view showing a positional relationship among two wafer stages, a reticle stage, a projection optical system, and an alignment system.
FIG. 4 is a plan view showing a configuration of a drive system for a wafer stage.
5A and 5B are diagrams for explaining a wafer transfer operation. FIG.
FIG. 6 is a flowchart showing time-sequential simultaneous processing in the exposure apparatus main body.
FIG. 7 is a diagram (No. 1) for describing simultaneous parallel processing using two wafer stages;
FIG. 8 is a diagram (No. 2) for explaining simultaneous parallel processing using two wafer stages;
FIG. 9 is a diagram (No. 3) for explaining the simultaneous and parallel processing using two wafer stages;
FIGS. 10A to 10C are diagrams respectively showing an aperture stop, a reticle pattern, and a predicted formation pattern when exposure is performed using the pattern in the first exposure operation. FIGS. 10D to 10F are diagrams respectively showing an aperture stop, a reticle pattern, and an expected formation pattern when the pattern is exposed using the pattern in the second exposure operation. FIG. It is a figure which shows the completion pattern formed as a result of double exposure.
FIG. 11 is a graph showing a result of simulating a change in throughput when the number of wafers in one lot is changed in various exposure apparatuses.
FIG. 12 shows the change in throughput when the configuration of each stage is changed for each exposure apparatus having different reticle stage maximum speed and acceleration and wafer stage maximum speed and acceleration when one lot is set to 25 sheets. It is a table | surface which shows an improvement rate.
13 is a graph showing an improvement rate of the throughput of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus, 11 ... Wafer loader system (part of conveyance apparatus), 31 ... Interface part, 33 ... Coater / developer, 37 ... Second wafer conveyance system (part of conveyance apparatus), 47 ... FOUP (buffer), 90 ... main controller (control device), 200 ... substrate processing system, RP1 ... pattern (first pattern), RP2 ... pattern (second pattern), W1-W25 ... wafer (substrate), WST1, WST2 ... wafer stage ( Substrate stage).

Claims (16)

An exposure method for performing multiple exposure on each of n (n is an integer of 2 or more) substrates using a single exposure apparatus,
A first step of sequentially performing a first exposure on the n substrates;
A second step of sequentially performing second exposure from the first substrate to the n-th substrate without developing any of the substrates after the first step;
The exposure apparatus has two substrate stages on which a substrate is placed,
The exposure method, wherein the first exposure and the second exposure on the n substrates are both performed alternately and continuously on the different substrate stages. In the first exposure in the first step, a first pattern is transferred to each of the n substrates,
2. The exposure method according to claim 1, wherein, in the second exposure in the second step, a second pattern different from the first pattern is transferred onto the transfer region of the first pattern on each substrate. . The exposure method according to claim 1, further comprising a third step of changing an exposure condition between the first step and the second step. An exposure method for forming a pattern by multiple exposure on each of a plurality of substrates using two substrate stages on which the substrates are respectively placed,
A substrate in the middle of multiple exposure placed on the other stage in parallel with the partial exposure of the multiple exposure on the substrate placed on one of the two substrate stages. Including a step of exchanging with a substrate in the middle of another multiple exposure. An exposure apparatus that performs multiple exposure on each of a plurality of substrates,
a buffer capable of storing n (n is an integer of 2 or more) substrates;
an exposure apparatus comprising: a transport device that transports p (2 ≦ p ≦ n) substrates in the middle of the multiple exposure and temporarily stores them in the buffer. In the multiple exposure, the first pattern in which the first pattern is transferred to each of the substrates, and the second pattern different from the first pattern is transferred onto the transfer region of the first pattern on each substrate. A second exposure to be performed,
6. The exposure apparatus according to claim 5, wherein the transport device temporarily stores each of the p substrates for which the first exposure has been completed in the buffer prior to the second exposure. The exposure apparatus according to claim 6, wherein at least one of the number p and the storage time is set based on a time during which the performance of the photosensitive agent applied on each substrate can be maintained. Having two substrate stages on which the substrate is placed;
7. The apparatus according to claim 6, further comprising a control device that performs processing such that the first exposure and the second exposure on the p substrates are alternately and continuously performed on different stages. 8. The exposure apparatus according to 7. 9. The exposure apparatus according to claim 8, wherein the control device performs a process such that the first exposure and the second exposure are performed on the same stage on each of the substrates. The control device performs, prior to the second exposure, the specific partition area selected during the alignment of the substrate performed prior to the first exposure and the alignment marks attached to the specific partition area for each of the substrates. The exposure apparatus according to claim 8 or 9, wherein the exposure apparatus is selected during alignment of the substrate. When the first exposure is performed on each of the plurality of partitioned regions by the scanning exposure method for each of the substrates, the control device determines a scanning direction when performing the second exposure on each partitioned region by the scanning exposure method. The exposure apparatus according to claim 8, wherein the exposure apparatus matches the first exposure. An exposure apparatus according to any one of claims 5 to 11;
And a coater / developer connected in-line to the exposure apparatus. A substrate processing system comprising: an exposure apparatus that performs multiple exposure on each of a plurality of substrates; and a coater / developer connected inline to the exposure apparatus,
a buffer capable of storing n (n is an integer of 2 or more) substrates;
a transport device that transports p (2 ≦ p ≦ n) substrates in the middle of the multiple exposure and temporarily stores them in the buffer;
The substrate is provided in any of the exposure apparatus, an interface unit for connecting the exposure apparatus and the coater / developer, and the coater / developer. 14. The substrate processing system according to claim 13, wherein at least a space in which the substrate is stored in the buffer has a chemically clean atmosphere. 15. The substrate processing system according to claim 13, wherein the buffer is an open / close type buffer having a lid member that can be opened and closed in a state where the inside is blocked from outside air. 16. The transport device according to claim 13, wherein the transport device returns the plurality of substrates to the coater / developer in the same order as transported from the coater / developer. Substrate processing system.

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