JP2001237167A - Exposure method and device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure method through which a light exposure operation can be quickly repeated as many times as required before a trouble such as a characteristic change of resist takes place when a substrate is subjected to a multi-exposure process. SOLUTION: Four units, an alignment state 21A, a wafer feed arm 21c, an exposure stage 11, and a wafer recovery arm 21d, out of various equipments comprising an exposure system are connected together into a transfer route in which a wafer can be circulated. One lot of wafers is defined as wafers one smaller in number than the units which constitute the transfer route. The wafers of one lot are successively supplied to the transfer route by a transfer robot connected to a coater/developer device (not shown in Figure) as shown in Figure 8 (a) to 8 (f), and the wafers are circulated in the transfer route, by which a light exposure operation is carried out as many times as required in a multi-exposure process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method and a device manufacturing method for manufacturing a semiconductor device or the like using an exposure apparatus.

[0002]

2. Description of the Related Art When manufacturing a semiconductor element or a liquid crystal display device, an image of a mask on which a desired circuit pattern (device pattern) is formed is transferred to a substrate surface (semiconductor wafer surface or liquid crystal glass substrate) through a projection optical system or the like. The photolithography process of transferring onto the (surface) is common.
At this time, an appropriate photosensitive material (resist) is applied to the substrate surface, and only a portion to which light has reached is exposed, so that a circuit pattern can be obtained on the substrate surface at once.

In recent years, there has been an increasing demand for finer circuit patterns for semiconductor elements and the like. This is due to the growing market demand for more integrated electronic circuit configurations. Against this background, a method of multiple exposure of a circuit pattern on a substrate surface has been devised. This is an attempt to transfer a plurality of circuit patterns to each shot area on one substrate (the same resist), miniaturize an electronic circuit, and further increase the degree of integration in one chip. This makes it possible to provide a high-performance electronic circuit with a smaller area.

[0004]

However, there are some difficulties in realizing the above multiple exposure. First, a plurality of circuit patterns to be transferred to the same region on the substrate surface must be positioned very accurately. Overlay (alignment) of multiple circuit patterns on the board surface
This is because in a situation where the accuracy is low, a problem such as distortion occurring in the relationship between the hierarchical circuits may occur, and as a result, an operation failure of a completed product may be caused.

There is also a problem of a resist applied on a substrate surface. Various types of light sources are currently provided for use in the exposure apparatus, and usually, there is a resist most suitable for each light source. For example, a typical light source, KrF
Excimer lasers (wavelength 248 nm) are widely used at present, and resists having the best photosensitive performance are developed and used for this light source.

[0006] However, it is known that some resists corresponding to the KrF excimer laser change remarkably with time. This is one obstacle when performing multiple exposure on the substrate surface. That is, in this case, 1
After performing the second exposure, the second exposure to be performed next must be performed as quickly as possible. Otherwise, the resist deteriorates and accurate transfer of the circuit pattern cannot be guaranteed.

However, the transfer operation to the substrate surface in the exposure apparatus is usually performed in units of lots of about 25 to 50 substrates. This is a measure that should be recommended from the viewpoint of improving the throughput. However, when performing multiple exposure by such a method (sequence), the first exposure is performed on the first substrate of the lot. After that, it is necessary to wait until the first processing for the number of substrates constituting the lot is completed before the second exposure is performed. Therefore, there is a great possibility that the resist will deteriorate during this time, and it cannot be said to be a preferable method.

As a countermeasure to avoid the above situation, for example, a buffer for temporarily storing a substrate may be separately provided near the exposure stage. However, in this case, a considerable change in the hardware of the exposure apparatus is necessary, and the cost is naturally high, which is not the best method. Note that so-called stitching exposure, in which a circuit pattern is transferred to a plurality of regions that partially overlap each other on a substrate, may cause the same problem as in the multiple exposure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. It is an object of the present invention to perform multiple exposures of a substrate immediately before a problem such as a change in properties of a resist occurs when performing multiple exposure of a substrate. It is an object of the present invention to provide an exposure method capable of completing the above exposure and a device manufacturing method using such an exposure method.

[0010]

The present invention employs the following means in order to solve the above-mentioned problems. That is, in the exposure method according to claim 1, there is a substrate that circulates in a transport path connecting three or more units, and in one of the three or more units, the exposure method transfers a mask pattern onto the substrate. In the method, when it is determined that predetermined processing has been completed for a substrate that has reached a predetermined unit of the three or more units, the substrate is taken out of the transport path. It is.

According to this, the substrate is on a circulating transport path connecting three or more units. In other words, the transfer of the master pattern is performed by circulating the transport path.
Operations such as performing a plurality of times on one substrate can be performed without unnecessarily moving the substrate. Further, when the substrate reaches a predetermined unit of the three or more units, and when it is determined that the predetermined processing has been completed, the substrate is taken out of the transport path. It can be seen that there is room for introducing a new substrate in the transport path.

For example, when there is a substrate occupying at least two units among three or more units, one substrate
The substrates are continuously subjected to the master pattern transfer, thereby speeding up the operation. Further, if the predetermined processing is to perform a plurality of transfer operations (that is, multiple exposure or stitching exposure) on one substrate, the substrates subjected to the multiple exposure are sequentially moved out of the transport path. And a new substrate can be introduced into the empty unit. from these things,
The operation of performing multiple exposure (or stitching exposure) on each of a plurality of substrates can be performed quickly as a whole.

According to a fifth aspect of the present invention, in the exposure method of transferring the first and second patterns onto a plurality of substrates using the same exposure apparatus, the substrate is loaded in the exposure apparatus. From the position to the exposure processing unit along the first path, and the substrate on which the first pattern has been transferred by the exposure processing unit is transported to the exit position for unloading to the outside. Returning to a path, and transferring the second pattern to the substrate by the exposure processing unit.

According to this, the substrate on the first path including the input position is sent to the second path including the exit position after the first pattern has been transferred by the exposure processing unit, and further, in the middle thereof. Is returned to the first route again. That is, the first path and the second path correspond to the circulating transport path described above. According to the present invention, the substrate returned to the first path is subjected to the transfer of the second pattern later. Since this is performed on a plurality of substrates, that is, exposure on a plurality of patterns can be continuously performed.

A more specific implementation of the continuous exposure for the plurality of patterns is, for example, to transfer the first pattern in the exposure processing section to a certain substrate, and then execute the second path from the second path. It is conceivable that an operation such as transferring the first pattern to another substrate before the re-loading into one path is performed. Further, the number of substrates to be processed can be smaller than the units constituting the first path and the second path, for example, (unit number-1) can be processed as one unit, that is, one lot.

In addition, if an alignment station is arranged on the first path, it can be expected that a certain degree of accurate positioning is performed when the substrate is loaded or re-loaded into the exposure processing section. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an example of an exposure apparatus for applying the exposure method of the present invention. FIG. 2 is a sectional view taken along the line AA shown in FIG. The exposure apparatus is composed of three mutually independent chambers as shown in FIGS. These are respectively
A main chamber 1 containing an exposure apparatus main body 10; a loader chamber 2 containing various devices (such as a loader) for introducing / collecting a wafer (substrate) and a reticle for exchange into / from the main chamber 1; The main chamber 1 and the loader chamber 2 are configured as an air conditioner chamber 3 having a device for performing air conditioning. As shown in FIG. 2, the loader chamber 2 is divided into upper and lower parts by a partition plate 2a.
The reticle loader system 22 is housed above.

The interior of each of the main chamber 1 and the loader chamber 2 is maintained in an appropriate environment by an air conditioner 31. The air conditioner 31 is provided with an air conditioning unit (not shown) corresponding to each of the chambers 1 and 2 in order to perform individual air conditioning control. In the loader chamber 2, the wafer loader system 21 and the reticle loader system 2
Since it is divided into two, air conditioning is also performed in a form corresponding to each of these systems. That is, the air conditioner 31 is provided with a total of three air conditioning units. Each of these air conditioning units is provided with a pipe 32 for sending or collecting a temperature-controlled gas (air or the like) to or from each of the chambers (1, 21, 22). In addition, one air conditioning unit may be used in common for each chamber, or a temperature control unit may be provided in front of the outlet of each chamber so that the temperature of gas supplied to each chamber can be set independently. Is also good.

The main chamber 1 is provided with an anti-vibration table 1b installed on a floor surface thereof through an anti-vibration pad 1a.
The exposure apparatus main body 10 is installed on the vibration isolating table 1b. As shown in FIG. 2, the exposure apparatus main body 10 includes an exposure stage 11, a column 12, a projection optical system 13 fixed in the middle thereof, and a reticle stage (or reticle holder) 1.
4 is schematically configured in such a manner as to be sequentially laminated. Above the reticle stage 14, there is further provided a light source and an optical system (such as an illumination optical system) for guiding exposure light emitted from the light source to the reticle. The light source and the optical system are not shown in FIGS. Further, the exposure processing section of the present invention corresponds to the exposure apparatus main body 10, but does not need to have all the components of the apparatus main body 10, and it is sufficient that at least the exposure stage 11 is included.

The exposure stage 11 is driven by an X
The stage 11 can be moved in the −Y direction.
When a wafer is mounted, an arbitrary position (shot area) on the wafer surface can be positioned below the projection optical system 13. The wafer and the projection optical system 13
Since it is necessary to perform a focusing operation and the like relating to both, the exposure stage 11 can also be operated in the vertical direction, that is, in the Z direction.

The column 12 is a member for holding a projection optical system 13 composed of a plurality of optical elements. The projection optical system 13 is an optical system for transmitting illumination light for exposure that has passed through the reticle and forming a pattern image of the reticle on the wafer. Furthermore, reticle stage 1
Reference numeral 4 denotes a stage for mounting a reticle on which a desired pattern is formed in advance. The reticle illuminates the reticle with illumination light for exposure, thereby defining a portion through which the illumination light passes and a portion where the illumination light is blocked.

The illumination light for exposure includes a bright line (for example, g line, i line) generated from a mercury lamp, a KrF excimer laser (wavelength 248 nm), and an ArF excimer laser (wavelength 1).
93 nm), F ₂ laser (wavelength 157 nm), or harmonics of a YAG laser or a metal vapor laser or a semiconductor laser is used. The exposure apparatus according to the present embodiment uses a KrF excimer laser as a light source among the various light sources.

In addition to the above, the exposure apparatus body 10
An optical device or the like for performing precise positioning with respect to each shot area on the wafer is provided. This is, for example, a position detection optical system (not shown) prepared separately from the projection optical system 13, thereby detecting an alignment mark formed on a wafer and using the drive source a1. Determination of the relative positional relationship between the wafer and the projection optical system 13, that is, accurate positioning of the shot area is performed before exposure.

The loader chamber 2 is, as described above,
The partition 2a divides the upper part into a chamber occupied by the wafer loader system 21 and the lower part into a chamber occupied by the reticle loader system 22.

First, the wafer loader system 21 will be described. The wafer loader system 21 loads a wafer from the outside of the exposure apparatus (for example, a coater / developer apparatus), unloads the wafer to the outside, and supplies / collects (loads) a wafer to / from the exposure apparatus main body 10 (exposure stage 11) in the main chamber 1.・ Unload). The wafer loader system 21 includes a horizontal slider 21X disposed in a direction along the X-axis in FIG.
Vertical axis slider 21Y, horizontal axis slider 21 along the axial direction
Transfer robot 21a attached to X, vertical axis slider 21
The two wafer supply and recovery arms 21c and 2c attached to Y
1d and an alignment stage (alignment station) 21A.

As shown in FIG. 1, the transfer robot 21a is a scalar type handling robot, and is installed so as to be movable along a horizontal axis slider 21X. In FIG. 1, the transfer robot 21a moves to the position P1.
Is shown. The transfer robot 21a itself
As shown in the enlarged view of FIG. 3, the translation unit includes a translation unit abX, abZ, a θ-axis, a rotation unit abR for an R-axis, and a hand unit abH. The X-axis movement is the horizontal axis slider 2
The operation along 1X and the Z-axis movement mean an operation in a direction perpendicular thereto. Further, the θ-axis rotation means a rotation operation about the Z-axis, and the R-axis rotation means a rotation operation with respect to the θ-axis moving unit (see arrow R in FIG. 3).

The horizontal axis slider 21X and the transfer robot 21a carry out and take in a wafer between a coater / developer device (hereinafter abbreviated as C / D device) and an exposure device. The C / D device includes a coater for applying a resist to a wafer, a developer for developing an exposed wafer, and the like, and is provided alongside the loader system chamber 2. That is, the wafer after the resist coating process in the coater is introduced into the exposure apparatus,
The exposed wafer is delivered to the developer. The present invention is not particularly limited with respect to a specific place of introduction and delivery, but in the present embodiment, the transfer is performed when the transfer robot 21a is at the position P1 or P2 shown in FIG. Has become.

The above-mentioned wafer supply and recovery arms 21c and 21d
One is used as a load arm and the other is used as an unload arm, and is installed so as to be movable along the vertical axis slider 21Y. These receive the wafer from the transfer robot 21a and supply (load) and collect (unload) the wafer to and from the exposure stage 11 of the exposure apparatus body 10. Therefore, the vertical slider 21
Y is provided so as to penetrate the loader system chamber 2 and the main chamber 1. However, when the wafer is supplied to the exposure apparatus main body 10, when the wafer is transferred from the transfer robot 21a to one of the wafer supply / collection arms 21c and 21d (load arm), the wafer is passed through the alignment stage 21A.

The alignment stage 21A has a predetermined positional relationship between the wafer and the exposure stage 11 with reference to an orientation flat portion (or a notch portion, hereinafter abbreviated as an OF portion) formed at the periphery of the wafer. Is a stage for roughly positioning the wafer. FIG. 4 shows an enlarged view of a portion related to the alignment stage 21A, and includes an adjustment table A1, a turntable A2, and an OF section detection sensor A3.
(See FIG. 2). In addition to the above, a centering sensor A4 is attached to the side of the adjustment table A1.

When a wafer is supplied from the transfer robot 21a to the alignment stage 21A, the wafer passes through the centering sensor A4. Centering sensor A
As shown in FIG. 5, which is a cross-sectional view taken along the line CC in FIG. 4, reference numeral 4 includes a light projecting unit A41 and a light receiving unit A42, and the wafer W passes between them. From such a configuration, it is understood that the light emitted from the light projecting unit A41 is not detected by the light receiving unit A42 when passing through the wafer W. Further, since the wafer W is substantially circular, the center position of the wafer W can be determined by calculation by measuring the light blocking time accompanying the passage of the wafer W described above. The center position of the wafer W is determined by the turntable A2 of the alignment stage 21A.
Transfer robot 21 so as to match the center position in
The attitude (position) of a is adjusted, and the wafer W is supplied to the turntable A2.

In the alignment stage 21A, the turntable A2 rotates around the axis in the Z-axis direction in a state where the wafer W is vacuum-sucked. Alignment stage 21
A includes, as shown in FIG.
32, an OF section detection sensor A3 comprising
The peripheral portion of the wafer W is the light projecting portion A31 and the light receiving portion A3.
It is located between the two. Therefore, when the wafer W rotates, the location of the OF section can be recognized. That is, while the light from the light projecting portion A31 is blocked at the normal peripheral portion, it is not blocked at the OF portion. In this way,
The relative positional relationship between the wafer W and the exposure stage 11 is roughly adjusted.

In the wafer loader system 21, a storage shelf 21S, a temporary storage shelf 21Q, and the like are provided in addition to the devices described above. The storage shelf 21S is a shelf for storing wafers waiting for exposure or wafers for which exposure has been completed.
This is because, as shown in the side view of the storage shelf 21S in FIG. 6, table S ₁ mounting a plurality stretched horizontally inside the box SB, ..., S _n
It is composed of In addition, the front and rear direction of the box SB is a blow-through. Wafer W plurality of table S _1, ..., but it will be gradually placed on S _n, this operation is achieved by in box SB, a hand portion abH of the transfer robot 21a is inserted Is done. Of course, the mounting table S _1, ..., is the same when the wafer is taken out from the S _n.

As shown in FIG. 1, on one inner side surface of the loader system chamber 2, there is provided a light projecting portion SP for emitting light passing through a blow-by portion in the front-rear direction of the box SB. A light receiving unit SC is provided on the other inner side surface of the chamber 2 facing the back surface of the storage shelf 21S so as to correspond to the light unit SP. These light emitting part SP and light receiving part SC
The mounting table S _1, ..., making it possible to determine whether or not there is a wafer on S _n. That is, if the light is blocked, it can be determined that the wafer is stored, and in the opposite case, it is determined that the wafer is not stored.

The hand part abH of the transfer robot 21a described above, the wafer supply / recovery arm 21c,
21d, turntable A2, the stage S _1, ..., S _n, etc.,
The part that comes into direct contact with the wafer is coated with a conductive ceramic material with a dense surface structure, or
The whole is made of the same material. This is a measure for preventing dust and the like from adhering to the wafer.

Next, the reticle loader system 22 will be described. As shown in FIG. 2, the reticle loader system 22 includes:
It is located above the wafer loader system 21 described above. The reticle loader system 22 includes a transport slider 22Y and two reticle supply / recovery arms 22a and 22b slidable along the transport slider 22Y. Also,
A handling robot 22R and a reticle storage shelf 22S are provided near the transport slider 22Y.

The transport slider 22Y and the reticle supply / recovery arms 22a and 22b supply / collect reticle to / from the reticle stage 14 of the exposure apparatus body 10. Therefore, the transfer slider 22Y is provided so as to penetrate the loader chamber 2 and the main chamber 1 similarly to the vertical slider 21Y in the wafer loader system 21 described above. However, in the penetrating part, the vertical slider 21Y of the wafer loader system 21 is located below, whereas the transport slider 22Y of the reticle loader system 22 is located above it.

The handling robot 22R takes out the reticle from the reticle storage shelf 22S and transfers it to the reticle supply / recovery arms 22a and 22b. In addition, the reverse operation is performed. The handling robot 22R is of a scalar type, and its outline is substantially the same as the transfer robot 21a of the wafer loader system 21 described with reference to FIG. That is, the Z-axis translation unit, θ
A shaft rotating unit, an R-axis rotating unit, and a hand unit are provided. However, the handling robot 22R is not provided with a translation unit for the X axis.

The reticle storage shelf 22S is a shelf for storing a plurality of reticles for replacement. That is,
It is possible to prepare a plurality of printing patterns, which are used when performing wafer multiple exposure, which will be described in detail later. To briefly explain the situation, at the time of multiple exposure, the reticle storage shelf 22S
Reticle is sequentially taken out, and the reticle is exchanged on the reticle stage 14 via the handling robot 22R and the transport system (22Y, 22a, 22b).

Finally, in this exposure apparatus, the operation of the exposure apparatus main body 10, the operation of the wafer loader system 21 and the operation of the reticle loader system 22, and the like, assure the smooth execution without interference. Such a control system (not shown) is provided. That is, in order to operate various devices constituting the exposure apparatus, the control system is accessed.

In the exposure apparatus described above, when performing an exposure operation on a wafer, first, the transfer robot 21a of the wafer loader system 21 receives the wafer from the C / D device (coater) and transfers the wafer while holding the wafer. The robot 21a moves along the horizontal axis slider 21X, and places a wafer on the alignment stage 21A. And
The wafer roughly positioned on the alignment stage 21A is transferred onto the exposure stage 11 along the vertical axis slider 21Y by the wafer supply / recovery arm 21c or 21d. After the exposure work is completed,
This time, the reverse operation described above is performed, and the wafer is transferred to the C / D device (developer). However, at this time, there is no intervention via the alignment stage 21A.

Here, considering the case where multiple exposure is performed, in the present embodiment, the last process of unloading the wafer to the C / D device (developer) is omitted, and the alignment stage 21A is again performed. An operation such as supplying a wafer to the wafer and an operation of exchanging a reticle with a conventional reticle when exposing the same wafer again are performed. This is illustrated in FIG. That is, a supply path (first path) connecting three of an “alignment stage J (input position), a“ wafer supply (collection) arm ”, and an“ exposure stage ”, and an“ exposure stage ” From the “wafer (supply) recovery arm” in the recovery path, assuming two paths, namely, a recovery path (second path) connecting the two “wafer (supply) recovery arm” (retreat position) Can consider one closed path for transporting the wafer to the "alignment stage", which means envisioning a transport path through which the wafer circulates.

In FIG. 7, if each of the equipment groups such as the “transport robot” and “exposure stage” is considered as an independent unit, the transport path connects these equipment groups in an annular shape. Can be defined as By the way, in a wafer exposure process, it is a general method to process a plurality of wafers into one lot and process the wafers as one unit for the purpose of improving throughput. In consideration of circulating one lot of wafers in the transfer path just described, it is feasible if each unit holds a smaller number of wafers than the number of units constituting the transfer path. You can see that there is. That is, in FIG. 7, when the number of wafers is three or less, the wafers can be circulated between the units. In the present embodiment, the number of wafers that can be circulated is defined as one lot.

On the assumption of the above-mentioned transfer path and the circulating transfer of one lot of wafers, the multiple exposure operation of the wafer using the above-mentioned exposure apparatus is performed by the following method, for example. Note that the multiple exposure here is assumed to be double exposure for transferring two different patterns to the same wafer. Further, the wafer supply / recovery arms 21c, 21d
Is used as a wafer supply arm (load arm) 21c far from the horizontal axis slider 21X and as a wafer recovery arm (unload arm) 21d near the horizontal axis slider 21X. And
The units constituting the circulating transport path are four units: an alignment stage 21A, a wafer supply arm 21c, an exposure stage 11, and a wafer recovery arm 21d.
The number of wafers in a lot is three.

First, a resist (photosensitive agent) is applied to the wafer surface by a C / D device. This resist coating is performed in units of one lot. Therefore, in this case, the wafer 3
The resist is applied to the sheets. When the resist coating is completed, the transfer robot 21a of the wafer loader system 21 sequentially carries these wafers into the exposure apparatus.

The transfer robot 21a loads the first wafer W1 from among the wafers of the one lot into the exposure apparatus as shown in FIG. 8A, and transfers it to the alignment stage 21A. When the first single wafer is placed on the alignment stage 21A, the transfer robot 21a becomes empty. Therefore, the transfer robot 2
1a, as shown in FIG. 8B, goes to the operation of loading the second wafer W2 from the previous one lot of wafers into the exposure apparatus.

Eventually, the first wafer W1 roughly positioned on the alignment stage 21A is transferred to the wafer supply arm 21c while maintaining its position. At this point, the second wafer W2 described above is introduced into the empty alignment stage 21A as shown in FIG. 8 (c), and the transfer robot 21a becomes empty accordingly. Carries the third wafer W3 into the exposure apparatus.

This means that all the wafers in one lot have been introduced, and the first wafer W1
1 will be passed. For the wafer that has reached the exposure stage 11, after a more precise positioning operation with respect to the shot area on the wafer is performed, a transfer operation, that is, an exposure operation is performed using the reticle on which the first pattern is formed. You. Then, when this exposure operation is completed, as shown in FIG.
1d receives the wafer, and the wafer supply arm 21c transfers the second wafer W2 on the alignment stage 21A to the exposure stage 11. In parallel with this, the third wafer W3 on the transfer robot 21a is sequentially sent to the alignment stage 21A and the wafer supply arm 21c.

When the exposure operation using the first pattern for the second wafer W2 is completed, the first wafer W1 is moved from the wafer recovery arm 21d to the alignment stage 21A as shown in FIG. Returned to. That is, at this point, the wafer is transferred from the recovery path to the supply path, and the first wafer W1 is again on the supply path to the exposure stage 11. When the transfer operation of the first pattern onto the third wafer W3 is completed, the reticle relating to the first pattern is collected from the reticle stage 14 by the reticle loader system 22 and returned to the reticle storage shelf 22S. Then, the reticle on which the second pattern is formed is supplied to the reticle stage 14.

When such an operation is continued, the first wafer W1 introduced first is replaced with the first wafer W1 shown in FIG. 8 when the second patanin exposure operation on the second wafer W2 is completed.
As shown in (f), it is returned to the transfer robot 21a. That is, the first wafer W1 is regarded as having undergone the predetermined processing, and departs from the circulating transport path and gets on the path for unloading the wafer to the C / D device (developer). At this time, since one empty space is created in the transport path, in parallel with continuing the exposure work on the second and third wafers W2 and W3,
The first wafer of the next lot is introduced.

In the same manner, the second and third wafers W
2. If W3 is also taken out of the transport path,
An exposure process similar to that described above, that is, an exposure process similar to that shown in FIGS. 8A to 8F is repeated for wafers constituting the next lot. However, at this time, when the processing for the first lot is completed, the reticle on which the second pattern is formed on the reticle stage 14 is left as it is, and is not replaced with the reticle of the first pattern. That is, in the processing for the second lot, the transfer of the second pattern is performed as the first exposure work, and then the transfer of the first pattern is performed as the second exposure work. Such a measure will be similarly applied to the following lots. In other words, in each lot, two cases of a double exposure in the order of the first pattern and the second pattern and a case of double exposure in the order of the second pattern and the first pattern are alternately performed. Will appear.

As described above, in the exposure method according to the present embodiment, a plurality of (one lot) wafers coated with a resist circulate on the transport path connecting the units constituting the exposure apparatus. This makes it possible to quickly complete multiple exposure using different patterns without causing useless movement (for example, exposure standby) of the wafer. This is particularly effective when an exposure operation has to be performed on a resist that is significantly deteriorated with time.

Further, when the work is transferred from the first lot to the next lot, the above-described method of changing the pattern transfer order between the lots without replacing the reticle can avoid unnecessary reticle exchange. In that sense, it greatly contributes to the improvement of the throughput. Incidentally, the change of the pattern transfer order does not affect the quality. Further, an alignment stage 21A is arranged as a component on the transport path, and is always passed through the alignment stage 21A before being sent to the exposure stage 11, so that precise positioning on the exposure stage can be quickly performed. It can be completed and the exposure operation can always be performed accurately.

In addition, as is apparent from the above description, such an exposure method does not require any change in hardware related to the exposure apparatus. Therefore, it can be implemented only by changing the software in the control system,
It can be realized at low cost.

In the above-described exposure method, a double exposure using two different patterns has been described, but the present invention is not limited to this. That is, it is clear that the above method can be applied mutatis mutandis even when performing three or more exposures on the same substrate. The same applies to the description regarding the pattern transfer order for each lot. For example, considering the case of performing a quadruple exposure now, regarding the first lot,
If the transfer is performed in the order of the fourth pattern to the fourth pattern, the first exposure for the next lot is performed using the fourth pattern.

Further, the present invention provides the above-described "alignment stage 21A" and "wafer supply arm 21".
c, "exposure stage 11", "wafer collection arm 21"
However, the present invention is not limited to the embodiment in which the transport path is composed of "d". For example, in FIG. 1, a transfer robot 21b (not shown in FIG. 1), which is movable along the horizontal axis slider 21X and is separate from the transfer robot 21a, is provided, and is configured by six units as shown in FIG. May be assumed. That is, in FIG. 9, a transport path newly added with “transport robot 21 a” and “transport robot 21 b” in addition to the four units in the previous embodiment is used as the transport path.

In this case, the supply paths are “alignment stage 21A” and “wafer supply arm 21”.
c) and the “exposure stage 11” are the same as those in the previous embodiment, but the collection paths are the “exposure stage 11”, “wafer collection arm 21d”, “transfer robot 21a”, and “transfer robot 21b”. Then, by connecting a path for transferring the wafer from the last “transfer robot 21b” to the “alignment stage 21A” in the supply path, a circulating transfer path is assumed. It is apparent that the above-described method can be applied to the multiple exposure method itself by using such a transport path. In particular, in the case of this example, it can be seen that the number of wafers that can be supplied on the transfer path is five with the number of units being 6-1, and the processing capacity is improved as compared with the previous embodiment.

Further, the storage shelf 21 described with reference to FIG.
By using S, the temporary storage shelf 21Q, and the like, it is possible to assume a transport path having a larger number of units, and it is understood that the processing capacity is gradually improved accordingly. At this time, if the light projecting unit SP and the light receiving unit SC for confirming the presence / absence of a wafer stored in the storage shelf 21S are used in an auxiliary manner, an efficient exposure operation can be performed.

Further, since the present invention is not limited to the configuration of the exposure apparatus shown in FIGS. 1 and 2, the present invention can be applied to a transport path to which other components are added. It is. For example, there is an exposure apparatus in which a peripheral exposure apparatus 50 as shown in FIG. 10 is attached to an alignment stage 21A, and the peripheral exposure apparatus 50 is an exposure apparatus provided independently of the alignment stage 21A. In, the peripheral exposure apparatus 50 may be counted as a constituent unit of the transport path. Incidentally, the peripheral edge exposure device 50 is a device provided to prevent dust from the wafer by separately exposing the resist on the peripheral portion of the wafer. This comprises at least a rotary table 51 and an optical system 52 for guiding illumination light for exposure. The illumination light for exposure may be guided by partially branching from the light source of the exposure apparatus body 10.
The wafer W is placed on the rotary table 51 and rotated, and the peripheral portion is exposed to the illumination light for exposure from the optical system 52, so that the resist at the peripheral portion is exposed.

The point is that the exposure method of the present invention can be applied to any type of exposure apparatus if the units constituting the transport path are appropriately selected. However,
As the number of units constituting the transport path increases, the processing capacity improves. However, when it is necessary to apply a resist that changes significantly with time, it is necessary to apply the resist from the first exposure to the second exposure. Don't leave them at long intervals. Great care must be taken in this regard.

In each of the above embodiments, the exposure operation (sequence) has been described on the premise of multiple exposure. However, the present invention can be applied to other than multiple exposure, such as stitching exposure. In stitching exposure, a large area circuit pattern is obtained by transferring a pattern to a plurality of regions where the peripheral portion partially overlaps on the substrate, and if a pattern to be transferred is different in a part of the plurality of regions. Sometimes For example, when performing the stitching exposure with the first pattern and the second pattern, after transferring the first pattern to half of the plurality of shot areas on the first substrate, the remaining substrates in the same lot, Two
The first pattern is transferred to each of the n-th substrates (n = (number of units−1)). Next, the reticle is replaced, the first substrate is placed on the exposure stage 11, and the second pattern is transferred to the remaining shot areas, and the second pattern is similarly applied to the second to n-th substrates. Transcribe. Therefore, the same effect as in the multiple exposure can be obtained in the stitching exposure.

When transferring a pattern to a large number of shot areas on the substrate, the large number of shot areas may be divided into a plurality of blocks, and a different pattern may be transferred for each block. In this case, the present invention can be applied, and it is possible to obtain exactly the same effects as those of the multiple exposure and the stitching exposure described above.

In each of the above embodiments, when transferring the same pattern (for example, the first pattern or the second pattern in the above-described multiple exposure) onto a plurality of shot areas on the substrate, a step-and-repeat method is used. And the step-and-scan method may be used.
A plurality of patterns used for multiple exposure, stitching exposure, and the like may be formed on the same reticle, or may be formed on different reticles.

Further, the illumination light for exposure is not limited to a far ultraviolet region or a vacuum ultraviolet region, but is a soft X-ray region having a wavelength of about 5 to 50 nm generated from a laser plasma light source or SOR, for example, a wavelength of 13. 4 nm or 11.5 n
The present invention is also applicable to an exposure apparatus using a charged particle beam such as EUV (Extreme Ultra Violet) light, hard X-ray, electron beam, or ion beam as exposure light for exposure, or a proximity type exposure apparatus. Thus, a similar effect can be obtained. The present invention is used not only for an exposure apparatus used for manufacturing an electronic device such as a semiconductor device, but also for an image pickup device (such as a CCD), a thin-film magnetic head, a display device, a micromachine, and a reticle (mask). The present invention can be applied to an exposure apparatus.

Incidentally, for a semiconductor device or the like, a step of designing the function and performance of the device, a step of manufacturing a reticle based on this design step, a step of manufacturing a wafer from a silicon material, and a step of manufacturing a reticle according to the sequence shown in FIG. It is manufactured through a step of transferring a pattern to a wafer, a step of assembling a device (including a dicing step, a bonding step, and a package step), an inspection snub, and the like.

[0065]

As described above, according to the first aspect of the present invention, since the substrate circulates through the transport path connecting the three or more units, the transfer of the mask pattern is performed a plurality of times on the same substrate. In the case of performing a predetermined process, for example, when the process is performed, the operation of the substrate can be completed quickly without waste. If it is determined that the substrate has reached the predetermined unit and the predetermined processing has been completed, the substrate is taken out of the transport path, and a new substrate is introduced into the transport path. It is possible to improve the throughput from the viewpoint of the entire exposure operation.

According to the exposure method of the second aspect,
Since the substrate is supplied to at least two or more units of the three or more units, the substrate occupying the two or more units can be continuously exposed,
Work efficiency can be improved.

According to the exposure method of the third aspect,
Since the predetermined processing is a multiple exposure, the above-described effects can be more effectively utilized. That is, from the start to the end of the multiple exposure, all the predetermined operations are performed while circulating through the transport path without making useless movement, so that the operations can be completed as a whole quickly. As described in the embodiment, this is particularly effective when a resist that changes significantly with time is used.

According to a fourth aspect of the present invention, in performing the multiple exposure, the pattern used at the time when the multiple exposure for the first substrate is completed is transferred to the next substrate to be supplied. Since the exchange is not performed when the exposure operation is performed, the trouble of pattern exchange can be saved, and the throughput can be improved.

According to the exposure method of the fifth aspect,
The substrate having received the transfer of the first pattern is returned to the first path including the input position from the middle of the second path including the exit position. Then, the substrate returned to the first path is subjected to the transfer of the second pattern later. Therefore, it is suggested that the exposure operation for a plurality of patterns can be continuously performed, and the exposure operation can be completed quickly.

According to the exposure method of the sixth aspect,
After transferring the first pattern to a certain substrate,
A plurality of substrates are supplied to the first and second paths to transfer the first pattern to another substrate before the second path is re-loaded into the first path. Thus, the exposure operation for the plurality of patterns can be performed on a plurality of substrates at a time, and this operation can be speeded up and the efficiency can be increased.

According to the exposure method of the seventh aspect,
Since the number of one lot of the substrate is defined to be smaller than the number of at least three units capable of holding the substrate on the path for re-transferring to the exposure processing section, The substrate can circulate in two paths, so that the exposure operation for the plurality of patterns can be performed without delay.

According to the exposure method of the eighth aspect,
Since the number of substrates in one lot is one less than the number of the at least three units, the maximum number of substrates that can be circulated through the first and second paths is processed,
The efficiency of the work can be further improved.

According to the exposure method of the ninth aspect,
After the substrate processing of one lot is completed, the operation of transferring the substrate of the next lot is started without switching the second pattern to the first pattern. Therefore, in the exposure operation for each lot, it is possible to save the trouble of pattern exchange. It is possible and work can be performed more quickly.

According to the exposure method of the tenth aspect, the alignment station is disposed on the first path, and the substrate returned from the second path to the first path passes through the exposure processing unit via the alignment station. The substrate to be received in the exposure processing unit has been accurately positioned to some extent. Therefore, more precise positioning performed by the exposure processing section can be completed quickly, and an accurate transfer operation can be expected. In addition, since this can be applied to all the substrates on the first and second paths, it is possible to speed up the entire operation and improve the accuracy.

According to the exposure method of the eleventh aspect, since the substrate is subjected to multiple exposure, each of the effects can be enjoyed to the maximum in the most suitable exposure method of multiple exposure.

[Brief description of the drawings]

FIG. 1 is a plan view showing an exposure apparatus.

FIG. 2 is a sectional view of the exposure apparatus shown in FIG.

FIG. 3 is an enlarged plan view showing a transfer robot provided in the exposure apparatus in FIGS. 1 and 2;

FIG. 4 is an enlarged plan view showing a portion related to an alignment stage provided in the exposure apparatus in FIGS. 1 and 2;

FIG. 5 is a front view showing a centering sensor attached to the alignment stage shown in FIG. 4;

FIG. 6 is an enlarged side view of a storage shelf provided in the exposure apparatus in FIGS. 1 and 2;

FIG. 7 is an explanatory view schematically showing a wafer circulating transfer path in the exposure apparatus shown in FIGS. 1 and 2.

FIG. 8 is an explanatory diagram illustrating an exposure method in the present embodiment using the exposure apparatus shown in FIGS. 1 and 2;

FIG. 9 is an explanatory diagram schematically showing a configuration different from the transport path shown in FIG. 7;

FIG. 10 is a side view showing a peripheral edge exposure apparatus.

[Explanation of symbols]

11 Exposure Stage 21A Alignment Stage (Alignment Station) 21a, 21b Transfer Robot (Unit) 21c, 21d Wafer Supply / Recovery Arm (Unit) 21S Storage Shelf 21Q Temporary Shelf 50 Peripheral Exposure Device W, W1, W2, W3 Wafer <Substrate>

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01L 21/68 H01L 21/30 514D 514A F term (Reference) 5F031 CA02 CA07 DA17 FA01 FA04 FA07 FA12 FA13 FA14 FA15 GA45 GA47 GA48 GA49 HA13 HA59 JA05 JA14 JA15 JA17 JA22 JA28 JA29 JA32 JA34 JA35 JA38 KA06 KA07 KA08 KA10 KA11 KA13 KA14 MA03 MA06 MA13 MA24 MA26 MA27 PA03 5F046 AA13 BA04 CA04 CD01 CD03 CD05

Claims (12)

[Claims] 1. An exposure method, comprising: a substrate circulating in a transport path connecting three or more units, and transferring a mask pattern onto the substrate in one of the three or more units. An exposure method that, when it is determined that predetermined processing has been completed for a substrate that has reached a predetermined unit among the units, the substrate is taken out of the transport path. 2. The exposure method according to claim 1, wherein the substrate is supplied to at least two of the three or more units. 3. The exposure method according to claim 1, wherein the predetermined processing is to perform the transfer a plurality of times on one substrate while exchanging the pattern of the mask. 4. After the predetermined processing is completed on the substrate on the transfer path, and the substrate is taken out of the transfer path, the transfer of a subsequently supplied substrate is performed until then. 4. The exposure method according to claim 3, wherein the exposure method is performed without replacing the used pattern of the mask. 5. An exposure method for transferring a first pattern and a second pattern onto a plurality of substrates by using the same exposure apparatus, wherein the substrate is exposed along a first path from an input position of the substrate in the exposure apparatus. Transporting the substrate on which the first pattern has been transferred by the exposure processing section to the first path in the middle of a second path for transporting the substrate to an exit position for unloading to the outside; An exposure method, wherein the transfer of the second pattern to the substrate is performed. 6. A method according to claim 1, wherein the substrate on which the first pattern has been transferred by the exposure processing section is returned to the first path in the middle of the second path and re-loaded into the exposure processing section.
6. The exposure method according to claim 5, wherein the first pattern is transferred to a single substrate. 7. A lot having a number of substrates smaller than the number of at least three units capable of holding the substrates on a path for re-transferring the substrates onto which the first pattern has been transferred to the exposure processing unit, 6. The exposure method according to claim 5, wherein the first and second patterns are transferred for each lot. 8. The exposure method according to claim 7, wherein the number of substrates in one lot is one less than the number of said at least three units. 9. The method according to claim 1, wherein the second pattern is transferred to a substrate of one lot to which the first pattern has been transferred.
9. The exposure method according to claim 7, wherein the second pattern is transferred onto a substrate of a next lot without switching the pattern to the first pattern. 10. An alignment station for detecting positional information of the substrate is arranged on the first path, and a substrate returned from the second path to the first path is sent to the exposure processing section via the alignment station. The exposure method according to claim 5, wherein the exposure method is re-loaded. 11. The exposure processing unit according to claim 1, wherein the first and second exposure processing units include:
The exposure method according to any one of claims 5 to 10, wherein the substrate is subjected to multiple exposure using a pattern. 12. A device manufacturing method, comprising a step of transferring a device pattern onto a photosensitive substrate using the exposure method according to claim 1.