Lithographic apparatus and device manufacturing method

The present invention relates to a lithographic apparatus including a projection system configured to project a patterned radiation beam onto a target portion of a substrate held on a substrate support, the patterned beam of radiation being patterned with a patterning device held by a patterning device support. The lithographic apparatus includes an exchangeable object handling apparatus for exchanging an exchangeable object with a exchangeable object station and a support, the exchangeable object being one of the substrate and the patterning device and the support being one of the substrate support and the patterning device support, the exchangeable object handling apparatus including an intermediate holding device for holding an exchangeable object, which intermediate holding device can interact with the support to place an exchangeable object on or take an exchangeable object from the support, and a robot which can exchange an exchangeable object with the support, the intermediate holding device and said exchangeable object station.

FIELD

The present invention relates to a lithographic apparatus and a method for manufacturing a device.

BACKGROUND

In conventional lithographic apparatus of the above-mentioned type an exchangeable object handling apparatus may be used for the exchange of exchangeable objects between a stationary exchangeable object station and an exchangeable object support on which the exchangeable object during an operational phase is supported. Such exchangeable object may be a substrate which is exchanged between a substrate station and a substrate support, such as a substrate table on which the substrate is supported during the transfer of a pattern on the substrate. The exchangeable object may also be a patterning device which is exchanged between a patterning device loading station and a patterning device support on which during an operational phase the patterning device is supported.

Production capacity of a lithographic apparatus is, in part, affected by the exchange time needed to take away, after illumination, a substrate, which is located on the substrate support, and to place another substrate on the substrate support for a subsequent illumination. In order to increase the capacity of the lithographic apparatus it is desirable to decrease this exchange time.

In order to keep the exchange time small, the substrate handling apparatus of a conventional lithographic apparatus includes a robot with a double end-effector, i.e. robot capable of holding at the same time two substrates in two different holding positions. The double end-effector can be rotated around its vertical axis so that one of the two holding positions can be turned to a position wherein the robot can exchange a substrate with the substrate support. In another position, usually when the double end-effector is rotated over 180 degrees, a substrate in the other of the two holding positions can be exchanged with the substrate support.

When a first substrate held in the substrate support is to be exchanged by a second substrate which is placed in a loading station, the second substrate can during the transfer of a pattern on the first substrate, be placed in one of the holding positions of the robot. When the transfer is finished, the first substrate is taken from the substrate support in the other one of the holding positions of the robot. After that the double end-effector is rotated the second substrate is placed on the substrate support. Subsequently a pattern can be transferred on that second substrate. During this pattern transfer the robot can place the first substrate in the loading station. As the robot can hold two substrates at the same time the robot with double end-effector makes a relative quick exchange of the first and second substrate possible.

However, in conventional substrate handling apparatus, the robot with double end-effector is a relative expensive part of the lithographic apparatus, also due to the space needed to make the movement of the robot and in particular the rotating movement of the double end-effector in the lithographic apparatus in the proximity of the substrate support possible.

Alternatively, two robots which each can exchange an exchangeable object with a stationary station and the support may be provided. However, this solution may be expensive and may require a lot of footprint.

SUMMARY

It is desirable to provide a lithographic apparatus including an improved exchangeable object handling apparatus for exchanging an exchangeable object, whereby the improved exchangeable object handling apparatus provides for an efficient change of exchangeable objects.

According to an embodiment of the invention, there is provided a lithographic apparatus including an illumination system configured to condition a radiation beam, a patterning device support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam, a substrate support constructed to hold a substrate, a projection system configured to project the patterned radiation beam onto a target portion of the substrate, and an exchangeable object handling apparatus for exchanging an exchangeable object with an exchangeable object station and a support, the exchangeable object handling apparatus including an intermediate holding device and a manipulator, each being designed to hold an exchangeable object, wherein the intermediate holding device is capable of exchanging an exchangeable object with the manipulator, wherein the manipulator is capable of exchanging an exchangeable object with the support, the intermediate holding device and the exchangeable object station, and wherein the intermediate holding device is positioned substantially closer to the support than the exchangeable object station.

According to another embodiment of the invention, there is provided a device manufacturing method including the steps of projecting, in an operational phase, a pattern from a patterning device placed on a patterning device support onto a substrate placed on a substrate support, and exchanging, in an exchanging phase, an exchangeable object between a support and an exchangeable object station by using a manipulator and an intermediate holding device, the intermediate holding device being positioned substantially closer to the support than the exchangeable object station, the manipulator being capable of exchanging an exchangeable object with the exchangeable object station, the support and the intermediate holding device, and the intermediate holding device being capable of exchanging an exchangeable object with the manipulator, wherein during exchange an exchangeable object is temporarily stored in the intermediate holding device.

In an embodiment of the invention, there is provided a lithographic apparatus including (a) an illumination system configured to condition a radiation beam; (b) a patterning device support configured to support a patterning device, the patterning device configured to pattern the beam of radiation to a form a patterned beam of radiation; (c) a substrate support configured to hold a substrate; (d) a projection system configured to project the patterned radiation beam onto the substrate, and (e) an exchangeable object handling apparatus configured to exchange an exchangeable object with one of the supports, said exchangeable object handling apparatus including (i) a manipulator; and (ii) an intermediate holding device, wherein the manipulator is configured to exchange the exchangeable object with the one support, the intermediate holding device and an exchangeable object station, and wherein the intermediate holding device is positioned substantially closer to the support than the exchangeable object station.

In yet another embodiment of the invention, there is provided an exchangeable object handling apparatus configured to exchange an exchangeable object on a support in a lithographic apparatus, the exchangeable object handling apparatus including a manipulator; and an intermediate holding device, wherein the manipulator is configured to exchange the exchangeable object with the support, the intermediate holding device and an exchangeable object station, and wherein the intermediate holding device is positioned substantially closer to the support than the exchangeable object station.

DETAILED DESCRIPTION

Step mode: the mask table MT and the substrate table WT are kept essentially stationary, while an entire pattern imparted to the radiation beam is projected onto a target portion C at once (i.e. a single static exposure). The substrate table WT is then shifted in the X and/or Y direction so that a different target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.

FIGS. 2 and 3show an embodiment of a substrate handling apparatus which in general is indicated with the reference number1. The substrate handling apparatus1includes a robot2and an intermediate holding device3configured to temporarily hold one substrate W. The robot2includes a single end-effector4which can hold one substrate W at the same time. The robot2can exchange a substrate W with a loading station5, the substrate support (or substrate table) WT and the intermediate holding device3. The exchange between the robot2and the support WT takes place in a first take-over area or first take-over region and the exchange between the robot2and the intermediate holding device3takes place in a second take-over area or second take-over region. It will be appreciated that in embodiments of the invention, a take-over region broadly refers to a region in the space where a take-over is performed.

The end-effector4of the robot2can be designed as any suitable gripping device that can hold a substrate W and may, for example, include mechanical, vacuum, electromechanical or electrostatic gripping devices.

In general any suitable manipulator can be used to exchange the substrate W between the loading station5, the intermediate holding device3and the support WT. The robot2ofFIGS. 2 and 3may be a multi-axis robot which in an efficient way can move the substrate W to the substrate support WT, the intermediate holding device3, and the respective loading station5. A robot is defined as a manipulator including two or more arms, the two or more arms being movably, for example, rotatably connected to each other, whereby at least one end of the robot is designed to manipulate an object within a certain space.

The loading station5is a stationary station, such as for example, an exchangeable box commonly used in the chip producing industry, and holds a number of substrates W which may be transferred by the robot2, directly or via the intermediate holding device3, to the substrate support WT. The robot1may also be suitable for exchanging a substrate W with any other station5asuch as an inspection station, buffer station or a cleaning station. When a substrate W is directly transferred from such other station5ato the substrate support WT or the intermediate holding device3(and thus not via the loading station5), this other station5ais also regarded to be a loading station in the context of this application.

The intermediate holding device3can interact with the substrate support WT to place a substrate W on or take a substrate W from the substrate support WT, and can interact with the robot2to exchange a substrate W with the robot2. The exchange between the intermediate holding device3and the substrate support WT takes place in a third take-over area or third take-over region.

The intermediate holding device3is located above an exchange position of the substrate support WT in which the substrate support WT is placed for the exchange of a substrate W. During the operational phase of the lithographic apparatus the substrate support WT may be moved, whereby it is possible that the intermediate holding device3is not anymore located above the substrate support WT. In an embodiment of the invention, the intermediate holding device3is mounted on a substantially vibration-isolated frame10so that the chance on take-over errors is reduced.

The intermediate holding device3may be located substantially closer to the substrate support WT in the exchange position (i.e. the position of the substrate support WT in which it is located during an exchange of a substrate W with said robot2or with said intermediate device3) than the loading station5. With substantially closer to the substrate support WT is meant that the distance between the intermediate holding device3and the substrate support WT in the exchange position is less than half, or may be less than a quarter of the distance between the substrate support WT and the loading station5.

It is however remarked that when an intermediate holding device3can directly exchange a substrate W with the substrate support WT it is not necessarily required that the intermediate holding device3be located substantially closer to the substrate support WT in the exchange position than the loading station5.

The interaction between the intermediate holding device3and the substrate support WT is in the embodiment ofFIGS. 2 and 3obtained by a lifting device6which is provided in the substrate support WT. This lifting device, which, for example, may be designed as a lifting pin-mechanism, which is often referred to as “e-pins”, can lift a substrate W from the support surface7of the substrate support WT to the third take-over area or third take-over region where the intermediate holding device3can take the substrate W from the lifting device6. In this same third take-over area or third take-over region the intermediate holding device3may place a substrate W on the lifting device6after which the substrate W can be lowered by retracting the lifting device6and be placed on the substrate support WT. In the embodiment of the invention shown inFIG. 6, the third take-over region is the region where the intermediate holding device3takes the substrate W from the lifting device6

The lifting device6may also be lifted to the first take-over area or first take-over region in which the robot2can exchange a substrate W with the substrate support WT. The position of the lifting device6wherein the lifting device6is retracted in the substrate support WT is in this application also referred to as retracted position. In this retracted position, a substrate W placed on the substrate support is supported on a support surface7of this substrate support WT. InFIG. 3, the first take-over region may be the region above the wafer table that is located at substantially a same height of the wafer W placed on the manipulator.

The intermediate holding device3may include any gripping device8that is suitable to hold the substrate W and may, for example, include mechanical, vacuum, electromechanical or electrostatic gripping devices. In the embodiment ofFIGS. 2 and 3the gripping device8includes pivotable arms which can be moved in the direction as indicated by the arrows. When the lifting device6moves a substrate upwards from the support surface7of the substrate support WT to the intermediate holding device3(i.e. the third take-over area or third take-over region), the pivotable arms are moved outwardly so that the substrate can be moved to a position above the position wherein the substrate is shown inFIG. 2. Subsequently, the pivotable arms are moved back to their initial positions and the lifting device6is retracted so that the substrate comes to rest on the pivotable arms as shown inFIG. 2.

In an alternative embodiment, the arms of the gripping device8are static and arranged in such a way that in a sideways direction (i.e. with a substantial horizontal movement) a substrate W can be brought in a position above the supporting parts of the arms8. In such embodiment, the lifting device6may move the substrate W to be exchanged to the same height as this position before or during that the substrate support WT is moved from the operational position to the exchange position. When the substrate support WT is moved into the exchange position the substrate is more or less slid into the gripping device8. When the substrate support WT is in the exchange position the lifting device6can be retracted so that the substrate W comes to rest on the arms of the gripping device8. In a reverse order a substrate W can be taken out of the intermediate holding device3. In a similar way, with a substantially horizontal movement, the robot2may exchange a substrate W with the intermediate holding device3. In this alternative embodiment any suitable static holding device may be used to hold the substrate W, which holding device3allows a sideways introduction of the substrate by the support WT and the robot2.

When, in the embodiment ofFIGS. 2 and 3, a first substrate W on the substrate support WT is to be replaced by a second substrate W that is placed in the loading station5the following acts can be followed with the substrate handling apparatus1. First the robot2takes the second substrate W out of the loading station5. This act may be taken during the operational phase of the lithographic apparatus in which a pattern from a patterning device is transferred to the first substrate W which is located on the substrate support WT in which case the operational phase and the exchanging phase overlap. After or during this act, but in any case after the operational phase, the substrate W is lifted from the support surface7of the support WT by the lifting device6to the third take-over area or third take-over region, so that the intermediate holding device3is able to take the first substrate W from the substrate support WT. Thereafter the robot places in the first take-over area or first take-over region the second substrate W on the lifting device6for which it may be needed that the lifting device is lowered over a certain distance to the first take-over area or first take-over region. When the second substrate W is placed on the lifting device6the lifting device6is lowered to the retracted position to place the second substrate W on the support surface7after which the operational phase with respect to the second substrate W may begin. The first substrate W which is held in the intermediate holding device3is in the second take-over area or second take-over region taken out of the intermediate holding device3by the robot2which transfers it consequently to the substrate loading station5. In the embodiment ofFIGS. 2 and 3the first take-over area or first take-over region is located at a lower height than the second and third take-over area or second and third take-over region, while the second and third take-over area or the second and third take-over region substantially overlap. In other embodiments the first, second and/or third take-over area may (at least partially) overlap, but also may include different areas depending on the arrangement and functioning of the robot2, the intermediate holding device3and the substrate support WT.

Instead of the method described above, it is also possible that the robot2takes in the first act the second substrate W out of the loading station5and places it in the intermediate holding device3before the operational phase has ended. Thereafter, the robot2may take the first substrate W from the substrate support WT after which the second substrate W may be placed on the substrate support WT by the intermediate holding device3.

In both methods the intermediate holding device3holds temporarily one of the substrates W1, W2to be exchanged in order to make an efficient exchange of the substrates W possible. The intermediate holding device3does not interact with the loading station5and holds maximal one substrate W at the same time. For this reason the intermediate holding device3may be of a relative simple design and is therefore relatively cheap. The presence of the intermediate holding device3makes it thus possible to quickly exchange a substrate W for another without the need for two robots or a relatively expensive robot with a double end-effector.

In the methods as described above it was assumed that at the beginning of the different acts of the method a substrate was present on the substrate support, which was to be exchanged with another substrate which was present in the loading station. This mode of exchange may be described as the input/output mode.

In general, three different types of exchange modes can be distinguished. In the input mode, a substrate is transferred from the loading station to the substrate support, whereby initially no substrate is present on the substrate support. In the output mode a substrate is transferred from the substrate support to the loading station, while no substrate is transferred from the loading station to the substrate support. As in both the input and the output mode only one substrate is exchanged there is no need to use the intermediate holding device during the exchange.

In an embodiment, the lithographic apparatus includes two or more intermediate holding devices each capable of holding one or more substrates. The input and output modes can in such embodiment be used to place a number of substrates on or take a number of substrates from the intermediate holding device, respectively (in that case the substrates are not transferred from or to the substrate support, but to or from the intermediate holding device).

During use of the lithographic apparatus the three different modes can be used in any suitable order. The application of any of these three modes in a lithographic apparatus with an intermediate holding device is deemed to fall within the scope of the invention.

InFIG. 4an alternative embodiment of the substrate handling apparatus1is shown. In this embodiment the lifting device6of the substrate support WT may lift the substrate W to the first take-over area or first take-over region wherein the robot2can exchange a substrate W with the substrate support WT. The gripping devices8of the intermediate holding device3are movable in a vertical direction using actuators9between a robot exchange position, making possible an exchange in the second take-over area or second take-over region, and a support exchange position, making possible an exchange in the third take-over area or third take-over region. In the support exchange position, in which position the intermediate holding device3is shown inFIG. 4, the intermediate holding device3can exchange a substrate W with the lifting device6of the substrate support WT in the above-mentioned third take-over area or third take-over region. In the robot exchange position, the intermediate holding device3can exchange a substrate W with the robot2in the second take-over area or second take-over region. The support exchange position is in the substrate handling apparatus1ofFIG. 4located at a lower height than the robot exchange position, so that when the intermediate holding device3is in the latter position the robot2can be placed between the intermediate holding device3and the substrate support WT to make an exchange between the robot2and the substrate support WT and between the robot2and the intermediate holding device3possible.

In an alternative embodiment, it is possible to use an intermediate holding device3, which can move vertically towards the substrate support WT so that substrate W can be taken directly from the support surface7of the substrate support WT without the use of a lifting system. In such embodiment of the substrate handling apparatus, the robot may place a substrate W on or take a substrate W from the substrate support WT without the substrate W being lifted from the substrate support WT by a lifting device. In yet another embodiment, it is also possible that instead of lifting device6the substrate support WT can be moved in a vertical direction to the first and the third take-over area or first and third take-over region. In this embodiment the intermediate holding device3may not have to be movable in a vertical direction.

In the above description a number of embodiments of a substrate handling apparatus have been described. Such apparatus could also be used for the exchange of patterning devices between the patterning device support (mask table) and a patterning device loading station, or to exchange any other exchangeable object which is applied in a lithographic apparatus, such as an exchangeable object used in the optical path of the lithographic apparatus. Such exchangeable object handling apparatus for the exchange of a substrate, patterning device or any other exchangeable object used in a lithographic apparatus is deemed to fall within the scope of the present application.

Examples of a patterning device handling apparatus are shown inFIG. 5andFIG. 6. InFIG. 5the patterning device handling apparatus1includes a robot2with an end-effector4for holding one patterning device, and an intermediate holding device3which can hold a patterning device MA, for example by a mechanical, vacuum, electrostatic or electromagnetic gripping device8. The intermediate holding device3is mounted on a substantially vibration-isolated frame (also referred to as “metro-frame”) and includes an actuator9to move the gripping device8of the intermediate holding device3in a vertical direction. Due to this vertical movement the intermediate holding device3can directly place a patterning device MA on or take a patterning device MA from the support surface7the patterning device support MT.

In the embodiment ofFIG. 5, it may also be possible that the patterning device support is movable in a vertical direction as indicated by the arrow (at the right side of the patterning device support MT). Depending on the vertical movement of the gripping device8and/or the patterning device support MT the third take-over area or third take-over region is situated where the patterning device is exchanged between the intermediate holding device8and the patterning device support MT. The first and/or second take-over area or first and/or second take-over region may in this embodiment overlap with the third take-over area or third take-over region.

InFIG. 6, another patterning device handling apparatus is shown. The patterning device handling apparatus1includes a robot2with a single end-effector4capable of holding one patterning device MA and two intermediate holding devices3each capable of holding one patterning device MA. The two intermediate holding devices3are located substantially closer to the patterning device support in the exchange position than the loading station5. With substantially closer to the patterning device support is meant that the distance between each of the intermediate holding devices3and the patterning device support MT in the exchange position is less than half, or may be less than a quarter of the distance between the patterning device support MT and the loading station5.

The two intermediate holding devices3can not directly exchange a patterning device with the patterning device support MT. The robot2can exchange a patterning device between the loading station5, the intermediate holding devices3and the patterning device support MT.

A first patterning device on the patterning device support can be exchanged by a second patterning device present in the loading station5using the following method. During the operational phase, i.e. when a pattern of the first patterning device MA supported on the patterning device support is transferred to a substrate, the robot can take the second patterning device MA out of the loading station5and place it on one of the intermediate holding devices3. After the operational phase the robot2takes the first patterning device MA from the patterning device support MT and places it on the other of the two intermediate holding devices3, after which the robot2takes the second patterning device MA and places it on the patterning device support MT. Now, in a new operational phase the illumination of a substrate can be started using the pattern of the second patterning device MA. In the mean time, the robot2can take the first patterning device from the intermediate holding device and place it in the loading station5.

Since the intermediate holding devices3are located close to the patterning device support MT the time needed for the exchange of the first and second patterning devices MA is relatively small, while at the same time a robot2with a single end-effector4is used, which reduces the costs and the space needed for the robot when compared to a robot with a double end-effector.

In an alternative embodiment there may also be provided one intermediate holding device capable of holding at least two patterning devices. In other embodiments, the intermediate holding device is only capable of holding two patterning devices MA at the same time, or there are provided two intermediate holding devices each capable of holding one patterning device MA. In this way a minimum of space is required to temporarily hold the patterning devices MA.

In the above-described embodiments of the substrate handling apparatus the support plane of a substrate W present on the substrate support WT was horizontal, whereby the support plane is defined as the plane in which the bottom side of the substrate W is lying when it is supported on the substrate support WT. In some known substrate supports WT this support plane is not horizontal but another direction for instance vertical or slanting. In such embodiments the location of the intermediate holding device would not be defined as above but rather as perpendicular to the support plane. Terms as higher and lower should in such a case be understood as further or closer spaced with respect to the support plane in this direction perpendicular to the support plane.