TWI505040B - Lithographic apparatus, method for measuring radiation beam spot focus and device manufacturing method - Google Patents

Description

Micro-mirror device, method for measuring spot focus of radiation beam and component manufacturing method

The present invention relates to a lithography apparatus, a method for measuring spot focus of a radiation beam, and a method for fabricating an element.

A lithography apparatus is a machine that applies a desired pattern to a component of a substrate or substrate. The lithography apparatus can be used, for example, in the fabrication of integrated circuits (ICs), flat panel displays, and other components or structures having fine features. In conventional lithography devices, patterned elements, which may be referred to as reticle or scale reticle, may be used to create circuit patterns corresponding to individual layers of an IC, flat panel display, or other component. This pattern can be transferred onto the substrate (component), for example, via imaging onto a layer of radiation-sensitive material (resist) provided on a substrate (eg, a germanium wafer or glass plate).

Instead of a circuit pattern, the patterned elements can be used to create other patterns, such as color filter patterns or dot matrices. Instead of a conventional mask, the patterned elements can comprise a patterned array comprising an array of individually controllable devices that produce circuitry or other suitable patterns. The advantage of this "maskless" system over conventional mask-based systems is that the pattern can be provided and/or changed more quickly and at less cost.

Thus, a maskless system includes programmable patterning elements (eg, spatial light modulators, contrast elements, etc.). The programmable patterned elements are programmed (eg, electronically or optically) to form a desired patterned beam using an array of individually controllable devices. Types of programmable patterning elements include micromirror arrays, liquid crystal display (LCD) arrays, grating light valve arrays Columns, self-emissive contrast element arrays, and the like.

The maskless lithography apparatus can be provided with, for example, an optical column for creating a pattern on a target portion of the substrate. The optical column can have a self-emissive contrast element configured to emit a beam of light, and a projection system configured to project at least a portion of the beam onto the target portion. The device can be provided with an actuator for moving the optical column or its components relative to the substrate. Thereby, the light beam can move relative to the substrate, and as the case may be, the substrate moves relative to the light beam. A pattern can be created on the substrate by "on" or "cut" the self-emissive contrast element during the movement.

In a lithography procedure, it is necessary to accurately focus an image projected onto a substrate. In particular, in some reticle lithography configurations, the focus range can be relatively small compared to reticle based systems having the same critical dimension. For example, in a reticleless system, a plurality of lenses can each be used to project a spot of radiation onto a substrate, thereby causing a relatively small focus range. Thus, a system can provide focus adjustment, such as adjusting focus or adjusting the image to focus on the substrate by, for example, adjusting the relative position between the substrate and the projection system in a direction parallel to the optical axis of the projection system. .

In addition to being able to provide focus adjustment, it is desirable to be able to measure the focus of each of the radiation beams that form the radiation spot on the substrate. For example, this measurement can be performed by projecting each beam or radiation onto an image sensor capable of measuring the diameter of the radiation spot. The focus can then be adjusted until the spot diameter is the desired size and/or the system can determine the distance from the projection system when the spot is the desired diameter. However, it may be difficult to obtain a focusing system The accuracy required, and/or this configuration may require relatively expensive image sensors and/or the system may not be able to perform focus measurements quickly enough.

Accordingly, there is a need, for example, to provide an improved focusing system including, for example, an improved focus measurement system.

In accordance with an embodiment of the present invention, a lithography apparatus is provided, the lithography apparatus comprising: a programmable patterning element configured to provide a plurality of radiation beams; a projection system configured to a plurality of radiation beams projected onto a substrate to form respective radiation spots; and a spot focus sensor system comprising: a grating configured to cause at least one of the radiation beam spots to be sequentially Projecting onto a plurality of different locations on the grating to perform a radiation spot focus measurement; a radiation intensity sensor configured to pass through the grating or from the grating at the plurality of locations Reflecting the radiation beam spot to detect radiation intensity; and a controller configured to determine a spot focus value from the detected radiation intensity corresponding to the plurality of locations.

In accordance with an embodiment of the present invention, a method for measuring spot focus of a radiation beam in a lithography apparatus is provided, the lithography apparatus comprising: a programmable patterning element configured to provide a plurality of a radiation beam; and a projection system configured to project the plurality of radiation beams to Forming a respective radiation spot on the substrate; the method comprising: sequentially projecting at least one of the radiation beam spots onto a plurality of different portions on a grating; using a radiation intensity sensor to free the plurality The spot is transmitted through the grating or the radiation beam spot reflected from the grating to detect the radiation intensity; and a spot focus value is determined from the detected radiation intensity corresponding to the plurality of portions.

According to an embodiment of the present invention, there is provided a method of fabricating a component, comprising: using the above method to measure a spot of the radiation beam of at least one of a plurality of radiation beams in a lithography device; and using The detected spot focus value is used to control at least one parameter of the lithography device while projecting the plurality of radiation beams onto a substrate.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings,

Figure 1 schematically depicts a schematic cross-sectional side view of the components of a lithography apparatus. In this embodiment, the lithography apparatus has individual controllable devices that are substantially stationary in the X-Y plane (as discussed further below), but need not be the case. The lithography apparatus 1 includes a substrate stage 2 for holding a substrate, and a positioning element 3 for moving the substrate stage 2 in up to 6 degrees of freedom. The substrate may be a resist coated substrate. In an embodiment, the substrate is a wafer. In an embodiment The substrate is a polygonal (eg, rectangular) substrate. In an embodiment, the substrate is a glass plate. In one embodiment, the substrate is a plastic substrate. In an embodiment, the substrate is a foil. In an embodiment, the lithography apparatus is suitable for roll manufacturing.

The lithography apparatus 1 further includes a plurality of individually controllable self-emissive contrast elements 4 configured to emit a plurality of beams. In an embodiment, the self-emissive contrast element 4 is a radiation emitting diode such as a light emitting diode (LED), an organic LED (OLED), a polymer LED (PLED) or a laser diode (eg, a solid state Laser diode). In one embodiment, each of the individually controllable devices 4 is a blue-violet laser diode (eg, Sanyo Model DL-3146-151). Such diodes may be supplied by companies such as Sanyo, Nichia, Osram and Nitride. In one embodiment, the diode emits, for example, UV radiation having a wavelength of about 365 nanometers or about 405 nanometers. In an embodiment, the diode can provide an output power selected from the range of 0.5 milliwatts to 200 milliwatts. In one embodiment, the size of the laser diode (bare die) is selected from the range of 100 microns to 800 microns. In an embodiment, the laser diode has an emission area selected from the range of 0.5 square microns to 5 square microns. In an embodiment, the laser diode has a divergence angle selected from the range of 5 degrees to 44 degrees. In one embodiment, the diode has a configuration to provide a total brightness greater than or equal to about 6.4 x 10 ⁸ W/(m ² .sr) (eg, emission area, divergence angle, output power, etc.) .

The self-emissive contrast element 4 is disposed on the frame 5 and is extendable in the Y direction and/or the X direction. Although a frame 5 is shown, the lithography apparatus can have a plurality of frames 5, as shown in FIG. The lens 12 is further disposed on the frame 5. The frame 5 is substantially stationary in the X-Y plane and, therefore, the self-emissive contrast element 4 and lens 12 are substantially stationary in the X-Y plane. The frame 5, the self-emissive contrast element 4 and the lens 12 are movable in the Z direction by the actuator 7. Alternatively or additionally, lens 12 can be moved in the Z direction by an actuator associated with this particular lens. Each lens 12 may be provided with an actuator as appropriate.

The self-emissive contrast element 4 can be configured to emit a beam of light, and the projection systems 12, 14 and 18 can be configured to project a beam onto a target portion of the substrate. The self-emissive contrast element 4 and the projection system form an optical column. The lithography apparatus 1 can include an actuator (eg, motor 11) for moving the optical column or components thereof relative to the substrate. The frame 8 configured with the field lens 14 and the imaging lens 18 can be rotated by an actuator. The combination of field lens 14 and imaging lens 18 forms movable optics 9. In use, the frame 8 rotates about its own axis 10, for example, in the direction indicated by the arrow in FIG. The frame 8 is rotated about the axis 10 using an actuator (eg, motor 11). In addition, the frame 8 can be moved in the Z direction by the motor 7, so that the movable optical member 9 can be displaced relative to the substrate stage 2.

A pore structure 13 having pores may be located above the lens 12 between the lens 12 and the self-emissive contrast element 4. The pore structure 13 can limit the diffraction effect of the lens 12, associated with the self-emissive contrast element 4 and/or the adjacent lens 12/self-emissive contrast element 4.

The depicted device can be used by rotating the frame 8 and simultaneously moving the substrate on the substrate table 2 under the optical column. When the lenses 12, 14 and 18 are substantially aligned with one another, the self-emissive contrast element 4 can emit a beam of light through the lenses. By moving the lenses 14 and 18, the image of the light beam on the substrate is spread over the substrate Partially scanned. By simultaneously moving the substrate on the substrate stage 2 under the optical column, portions of the substrate that are subjected to the image of the self-emissive contrast element 4 also move. Self-emissive contrast element 4 by "on" and "off" at high speed under control of the controller (eg, when self-emissive contrast element 4 is "off"), has no output or has a threshold below Output, and having an output above the threshold when the self-emissive contrast element 4 is "on"), controlling the rotation of the optical column or its components, controlling the intensity of the self-emissive contrast element 4, and controlling the speed of the substrate, The pattern is imaged in a resist layer on the substrate.

2 depicts a schematic top view of the lithography apparatus of FIG. 1 with self-emissive contrast elements 4. Similar to the lithography apparatus 1 shown in FIG. 1, the lithography apparatus 1 comprises: a substrate stage 2 for holding the substrate 17; a positioning element 3 for moving the substrate stage 2 in up to 6 degrees of freedom; A level sensor 19 is used to determine the alignment between the self-emissive contrast element 4 and the substrate 17, and to determine whether the substrate 17 is at a level relative to the projection of the self-emissive contrast element 4. As depicted, the substrate 17 has a rectangular shape, however, or alternatively, the circular substrate can be processed.

The self-emissive contrast element 4 is disposed on the frame 15. The self-emissive contrast element 4 can be a radiation emitting diode, such as a laser diode (eg, a blue-violet laser diode). As shown in Figure 2, the self-emissive contrast element 4 can be configured as an array 21 extending in the X-Y plane.

The array 21 can be a narrow line. In an embodiment, array 21 can be a one-dimensional array of self-emissive contrast elements 4. In an embodiment, array 21 can be a two-dimensional array of self-emissive contrast elements 4.

A rotating frame 8 can be provided, which can be in the direction indicated by the arrow Rotate. The rotating frame can be provided with lenses 14, 18 (shown in Figure 1) for providing images of each of the self-emissive contrast elements 4. The device can be provided with an actuator for rotating the optical column comprising the frame 8 and the lenses 14, 18 relative to the substrate.

Figure 3 depicts a highly schematic perspective view of a rotating frame 8 with lenses 14, 18 at its periphery. A plurality of beams (10 beams in this example) are incident on one of the lenses and projected onto a target portion of the substrate 17 held by the substrate stage 2. In one embodiment, the plurality of beams are arranged in the form of a straight line. The rotatable frame is rotatable about an axis 10 by an actuator (not shown). Due to the rotation of the rotatable frame 8, the light beam will be incident on the sequential lenses 14, 18 (field lens 14 and imaging lens 18) and will be deflected upon incidence on each of the sequential lenses, thereby facilitating along the substrate The portion of the surface of the 17 travels as will be explained in more detail with reference to FIG. In one embodiment, each beam is produced by a separate source (i.e., a self-emissive contrast element, such as a laser diode (not shown in Figure 3)). In the configuration depicted in Figure 3, the beam is deflected and focused by the segmented mirror 30 to reduce the distance between the beams, thereby enabling a greater number of beams to be projected through the same lens and to achieve resolution as discussed below. Degree requirements.

As the rotatable frame rotates, the beam is incident on the sequential lens, and whenever the lens is irradiated with the beam, the location where the beam is incident on the surface of the lens moves. Because the beam is projected onto the substrate differently (e.g., differently deflected) depending on where the beam is incident on the lens, the beam (when it reaches the substrate) will undergo a scanning movement each time through a subsequent lens. Reference See Figure 4 for a further explanation of this principle. FIG. 4 depicts a highly schematic top view of the components of the rotatable frame 8. The first beam set is represented by B1, the second beam set is represented by B2, and the third beam set is represented by B3. Each set of beams is projected through respective sets of lenses 14, 18 of the rotatable frame 8. As the rotatable frame 8 rotates, the light beam B1 is projected onto the substrate 17 during the scanning movement, thereby scanning the area A14. Similarly, beam B2 scans region A24 and beam B3 scans region A34. While rotating the rotatable frame 8 by the corresponding actuator, the substrate 17 and the substrate stage move in the direction D, which may be along the X-axis as depicted in FIG. 2, thereby being substantially perpendicular to the area A14, The scanning direction of the beam in A24 and A34. Due to the movement of the second actuator in the direction D (for example, by the movement of the substrate table motor by the corresponding substrate table motor), the sequential scanning of the light beams is projected when the sequential lens projection by the rotatable frame 8 is performed, so that Substantially abutting each other, causing substantially adjacent regions A11, A12, A13, A14 for each successive scan of beam B1 (regions A11, A12, A13 were previously scanned and A14 is currently scanned, as shown in Figure 4), Causes areas A21, A22, A23, and A24 for each successive scan of beam B2 (areas A21, A22, A23 were previously scanned and A24 is currently scanned, as shown in Figure 4) and caused each sequence for beam B3 Scanned areas A31, A32, A33, and A34 (areas A31, A32, A33 were previously scanned and A34 is currently scanned, as shown in Figure 4). Thereby, while rotating the rotatable frame 8, the areas A1, A2, and A3 of the substrate surface can be covered as the substrate moves in the direction D. Projection of multiple beams through the same lens will allow the entire substrate to be processed in a shorter time range (at the same rotational speed of the rotatable frame 8) because: for each pair of lenses By passing, a plurality of beams scan the substrate with each lens, thereby allowing an increase in displacement in the direction D for sequential scanning. From a different point of view, for a given processing time, when multiple beams are projected onto the substrate via the same lens, the rotational speed of the rotatable frame can be reduced, thereby potentially reducing the effects attributed to high rotational speeds, such as , deformation, wear, vibration, disturbance, etc. of the rotatable frame. In one embodiment, the plurality of beams are configured to be at an angle to the tangential direction of rotation of the lenses 14, 18, as shown in FIG. In an embodiment, the plurality of beams are configured such that each beam overlaps or is adjacent to a scan path of the adjacent beam.

An additional effect of the simultaneous projection of multiple beams by the same lens can be found when the tolerance is relaxed. Due to lens tolerance (positioning, optical projection, etc.), sequential regions A11, A12, A13, A14 (and/or regions A21, A22, A23 and A24, and/or regions A31, A32, A33 and A34) The location of the display can show some degree of inaccuracy relative to each other. Therefore, some overlap between the sequential areas A11, A12, A13, A14 may be required. In the case of a 10% overlap of a beam, for example, the processing speed will be reduced by a factor of 10% with a single beam simultaneously passing through the same lens. In the case where 5 or more beams are simultaneously projected through the same lens, 10% of the same overlap will be provided for every 5 or more projected lines (similarly referring to one of the beam examples above), thus The total overlap is reduced by a factor of about 5% or more to 2% or less, thereby having a significantly lower effect on the overall processing speed. Similarly, projecting at least 10 beams can reduce the total overlap by a factor of about 1/10 of the original. Therefore, the effect of tolerance on the processing time of the substrate can be due to multiple beams. Reduced by the simultaneous projection of the same lens. Alternatively or additionally, more overlap may be allowed (thus allowing for a larger tolerance band) because of its low effect on processing (if multiple beams are simultaneously projected by the same lens).

Instead of projecting multiple beams simultaneously through the same lens or in addition to projecting multiple beams simultaneously through the same lens, an interlacing technique can be used, however, this situation may require a more stringent match between the lenses. Thus, at least two beams that are simultaneously projected onto the substrate via the same lens in the lens have a mutual spacing, and the lithography apparatus can be configured to operate the second actuator to move the substrate relative to the optical column to have The light beam projected in the pitch is then projected.

To reduce the distance between successive beams in the group in direction D (by, for example, achieving a higher resolution in direction D), the beams may be diagonally disposed relative to each other relative to direction D. The pitch can be further reduced by providing a segmented mirror 30 in the optical path, each segment being used to reflect a respective one of the beams, the segments being configured to oppose the beam incident on the mirrors The spacing is reduced to reduce the spacing between the beams reflected by the mirrors. This effect can also be achieved by a plurality of fibers, each of which is incident on a respective one of the fibers, the fibers being configured to be along the optical path relative to the beam upstream of the fibers The spacing is used to reduce the spacing between the beams downstream of the fibers.

Alternatively, an integrated optical waveguide circuit having a plurality of inputs can be used to achieve this effect, with each input being used to receive one of the beams. The integrated optical waveguide circuit is configured to reduce the integrated light along the optical path relative to the spacing between the beams upstream of the integrated optical waveguide circuit Learn the spacing between the beams downstream of the waveguide circuit.

A system for controlling the focus of the image projected onto the substrate can be provided. A configuration can be provided to adjust the focus of the image by a component or all of the projected projections of the optical column as discussed above.

As depicted in FIG. 5, the focus adjustment configuration can include a radiation beam expander 40 that is configured such that an image of the programmable patterning element 4 projected onto the field lens 14 (discussed above) is via The beam expander 40 is projected to project. Field lens 14 and imaging lens 18 (discussed above) are configured such that an image projected onto field lens 14 is projected onto a substrate supported on substrate table 2. Thus, by adjusting the position of the image projected onto the field lens 14 in a direction substantially parallel to the optical axis 46 of the projection system, the focus of the image formed at the level of the substrate can be adjusted. As will be discussed further below, the radiation beam expander 40 is used to provide this adjustment of the position of the image projected onto the field lens 14.

This situation may be advantageous because it means that focus adjustment can be performed without adjusting the position of the substrate relative to the projection system. This situation can achieve accurate focus control independently for different regions positioned across the full width of the illumination field on the substrate. For example, each optical column or component thereof can have the independent ability to adjust the focus of the image projected onto it from the substrate.

Moreover, this configuration may not require adjustment of the position of the field lens 14 or imaging lens 18 in a direction parallel to the optical axis 46 of the projection system. This control may be difficult in configurations in which the field lens 14 and imaging lens 18 are configured to move in a direction perpendicular to the optical axis 46 of the projection system, as discussed above. For example, as depicted in Figure 5 and configured as discussed above Consistently, the field lens 14 and imaging lens 18 can be mounted to a movable (eg, rotating) frame 8 that is driven by the first actuator system 11.

The radiation beam expander 40 can be formed from a pair of axially aligned positive lenses 41,42. The lenses 41, 42 can be fixedly positioned relative to each other, for example, by a rigid support frame 43.

In an embodiment, the radiation beam expander 40 can be configured such that it is both an object-space telecentric and an image-space telecentric. It should be understood that in terms of object-space telecentricity, it means that the entrance pupil is located at infinity, and in terms of image-space telecentricity, it means that the exit pupil is located at infinity.

A second actuator system 44 can be provided and configured to control the position of the radiation beam expander 40 in a direction substantially parallel to the optical axis 46 of the projection system. In particular, the second actuator system 44 can be configured to act on the support frame 43 to adjust the position of the first lens 41 and the second lens 42 relative to the field lens 14 while maintaining the first lens 41 and the second The relative position of the lens 42.

The second actuator system 44 can be configured to help ensure that the radiation beam expander 40 only moves in a direction substantially parallel to the optical axis 46 such that it does not substantially exist in a direction perpendicular to the optical axis 46 of the projection system. The movement of the radiation beam expander 40. The movement of the beam expander 40 in a direction parallel to the optical axis 46 of the projection system is used to adjust the position of the image of the programmable patterning element 4 projected onto the field lens 14.

A controller 45 can be provided that is adapted to control the second actuator 44 to move the radiation beam expander 40 in an appropriate manner to provide desired focus control of the image projected onto the substrate. In particular, the movement of the radiation beam expander 40 along the optical axis 46 of the projection system and subsequent to the substrate The focus shift is proportional. Thus, the controller can store a certain multiple of the system and use this multiple to convert the desired focus shift at the substrate to the appropriate movement of the radiation beam expander 40. Controller 45 can then control second actuator system 44 to provide the desired movement.

For example, by measuring the distortion of the upper surface of the substrate at the target portion where the image is to be projected, the position of the substrate 17 and/or the substrate table 2 can be measured to determine the desired focus shift at the level of the substrate. . The previously determined information about the focus shift and focus on the spot of each of the radiation beams projected onto the substrate can be combined. The distortion of the upper surface of the substrate may be mapped prior to exposing the pattern on the substrate, and/or the distortion of the upper surface of the substrate may be measured for the portion of the substrate immediately prior to projecting the pattern onto each portion of the substrate.

The multiple of the shift of the radiation beam expander 40 to the focus shift at the substrate can be determined by the following formula: (1/B ² ) / (A ² -1) where A is the magnification of the radiation beam expander 40 And B is the magnification of the optical system from the lens 14 (the radiation beam expander projects the image of the programmable patterning element onto the lens 14) to the substrate, ie, the combination of the combination of the field lens 14 and the imaging lens 18 rate.

In one configuration, the combined system of field lens 14 and imaging lens 18 may have a magnification of 1/15 (i.e., reduction ratio), and radiation beam expander 40 may have a magnification of two. Therefore, in the case of using the above formula, it will be seen that for a focus shift of 25 microns at the level of the substrate, the movement of the radiation beam expander should be 1.875 mm.

As mentioned above, a focus configuration can be provided separately for each optical column within the lithography apparatus. Accordingly, it should be appreciated that each optical column can include a respective radiation beam expander 40 and associated actuator system 44 that is configured to be substantially parallel to the optical axis 46 of the projection system. The respective radiation beam expanders 40 are moved.

Figure 6 depicts a configuration of a spot focus sensor system in accordance with an embodiment of the present invention. As shown, the spot focus sensor system includes a grating 50 and a radiance intensity sensor 51 (such as a photodiode or other photodetector). The grating 50 and the radiance intensity sensor 51 are configured such that the radiance intensity sensor 51 can detect the intensity of the radiation transmitted through the grating 50 as the radiation beam 52 is projected onto the grating 50.

In the depicted configuration, the grating 50 can be formed as a plurality of chrome strips 53 formed on the substrate 54. Other constructions of the grating can be used. Substrate 54 can be selected to be substantially transparent to radiation (eg, formed of SiO ₂ ). A radiation intensity sensor 51 can be formed on the side of the substrate 54 opposite the grating 50. The pitch P of the grating 50 can be selected to be of the same order of magnitude as the desired spot of the radiation beam to be projected onto the substrate (e.g., the same size as the desired spot of the radiation beam to be projected onto the substrate).

As shown in FIG. 6, if the relatively focused beam 52 is projected onto the grating 50 such that the spot is incident on the gap between the chrome strips 53 of the grating 50, substantially all of the intensity of the radiation beam can be transmitted through to the sense of radiation intensity. The detector 51 causes the maximum possible radiation intensity received at the radiation intensity sensor 51. In contrast, if the radiation beam 52' is incident on one of the chrome strips 53, little or no radiation beam can be transmitted through to the radiant intensity sensor 51, thereby The minimum possible radiation intensity received at the radiation intensity sensor 51 is caused.

The spot focus sensor system can be configured to cause the radiation beam 52 to scan across the grating 50 such that the radiation beam 52 is projected onto the grating 50 at a plurality of locations (and/or causing the grating 50 to move relative to the beam 52 The beam 52 is incident on the grating 50 at a plurality of locations). As shown in FIG. 6, if the beam or radiation 52 is relatively well focused at the level of the grating, there will be a significant contrast between the maximum radiation intensity level received at the radiation intensity sensor 51 and the minimum radiation intensity level.

However, if the radiation beam 52 is not well focused at the level of the grating, then substantially no substantial portion of the beam 52 will pass through the point adjacent the gap between the chrome strips 53 and there is no substantial presence of the radiation beam 52'. All will be incident on a single chrome strip 53 and thus not transmitted to the point of radiant intensity sensor 51. Therefore, under this condition, the difference between the maximum radiation intensity received at the radiation intensity sensor 51 and the minimum radiation intensity will be reduced.

Thus, the spot focus sensor system can include a controller 55 that is configured to control the spot focus sensor system. Controller 55 can be configured to receive a signal from radiation intensity sensor 51 that corresponds to the level of radiation intensity received at radiation intensity sensor 51. From these signals, controller 55 can determine the focus of beam 52 at grating 50. For example, the controller 55 can determine the spot focus value. This spot focus value may represent a measure of the focus range of the beam 52 for the position of the grating 50 relative to the projection system. Alternatively or additionally, the spot focus value may represent the distance from the projection system to the point at which the radiation beam 52 is at the best focus or acceptable focus.

As discussed above, in order for the controller 55 to have sufficient information to determine light The point focus value is projected onto the grating 50 at a plurality of locations. This situation enables identification of the maximum radiation intensity level and minimum radiation intensity level received at the radiation intensity sensor 51. Controller 55 can be configured to control the relative movement between grating 50 and beam 52 during spot focus measurement. Accordingly, the controller 55 can directly or indirectly control one or both of the actuators 50 to move the grating 50 via the controller of the lithography apparatus, and can be used to move the beam 52. One or more components of the projection system.

Figure 7 schematically depicts the signal I output from the self-radiation intensity sensor 51 when there is relative movement between the radiation beam 52 and the grating 50, i.e., the signal I at the range of the position of the grating 50 relative to the radiation beam 52. . As shown, the signal I includes a plurality of maximum values and a plurality of minimum values corresponding to the projection of the radiation beam 52 to the space between the chrome strips 53 and onto the chrome strip 53 respectively.

To determine the spot focus value, the controller 55 can analyze the signal from the radiation intensity sensor 51 to identify the value of the maximum intensity I _{max and} the value of the minimum intensity I _min . From this value, the controller 55 can determine the contrast value. For example, the contrast value Cv can be determined from the following equation: However, it should be understood that another definition of contrast can be used.

Therefore, the controller 55 can obtain a value for determining the contrast of the spot focus value. One of the contrast values determined for the different positions of the surface of the grating 50 in the direction parallel to the optical axis of the beam 52 relative to the projection system can be used. Value to determine the spot focus value. However, this system may be inconvenient because it may be necessary to provide calibration to account for, for example, changes in the intensity of the radiation beam and changes in the response of the radiation intensity sensor 51.

Thus, in an embodiment, the spot focus sensor system is configured to determine a contrast value of the surface of the grating 50 relative to the projection system in a direction parallel to the optical axis of the beam 52. By identifying the portion of the grating 50 in the direction parallel to the optical axis of the beam 52, at which the contrast value reaches its maximum value, it is possible to identify the best focus position and thus the spot focus value.

In an embodiment, the controller 55 can be configured to receive information corresponding to the position of the grating 50 relative to the projection system in a direction parallel to the optical axis of the beam 52, and/or can directly or indirectly control the The position of the surface of the grating 50 incident with the beam 52 relative to the projection system.

In an embodiment, the spot focus sensor system can be configured to determine the contrast of the surface of the grating 50 incident on the beam 52 in a direction parallel to the optical axis of the beam 52 relative to a plurality of portions of the projection system value. Controller 55 can then identify the best focus position by selecting the position at which the contrast value has the highest value identified.

In an alternate embodiment, controller 55 may fit a curve that determines the location of the surface of grating 50 incident on beam 52 in a direction parallel to the optical axis of beam 52 relative to the projection system. The contrast value is related. The controller 55 can then determine the best focus point and again determine the spot focus value by identifying the position corresponding to the maximum value of the curve.

This configuration can have improved accuracy because it can be reduced in the system The effect of any error. This situation may be particularly relevant because the system may have a relatively high sensitivity to errors near the best focus position. For example, the change in contrast value of the grating 50 relative to a given movement of the projection system can be relatively small near the best focus position. The accuracy can be improved by including the measurement of the contrast value from a position far from the best focus point.

As shown in Figure 8, the grating 50 of the spot focus sensor system and (as appropriate) the associated radiant intensity sensor 51 can be provided on the substrate table WT of the lithography apparatus. For example, as shown, the grating 50 can be provided adjacent to a region where the substrate W can be positioned. This portion may be advantageous because the actuator system 60 provided to control the position of the substrate table WT relative to the projection system during formation of the pattern on the substrate W can be used to control the grating 50 during measurement of the spot focus value. position.

For example, the actuator system 60 for controlling the position of the substrate table WT can be used to scan the grating 50 relative to the beam 52 in a direction substantially perpendicular to the optical axis of the beam 52 to project the beam 52 onto the grating 50. On a plurality of parts to determine the contrast value.

Alternatively or in addition, the actuator system 60 for the substrate table WT can be used to adjust the position of the substrate table WT in a direction substantially parallel to the beam 52, and thus adjust the position of the grating 50. Thus, the procedure can be repeated at a plurality of locations parallel to the optical axis of the beam 52 to obtain multiple measurements of the contrast value (as discussed above) in order to find the location at which the contrast value is maximized.

In an embodiment, the actuator system for controlling the position of the substrate table WT The system 60 may be capable of tilting the upper surface of the substrate table WT at an oblique angle relative to the optical axis of the beam 52, as shown in Figure 9 (as will be appreciated, Figure 9 depicts a schematic view). Thus, the upper surface of the grating 50 (which may be parallel to the upper surface of the substrate table WT) may also be beveled relative to the optical axis of the beam 52.

Subsequently, the actuator system 60 for controlling the position of the substrate table WT can move the substrate stage in a direction substantially perpendicular to the optical axis of the beam 52, and thus move the grating 50. In this configuration, it will be appreciated that the beam 52 can be projected onto a region of the grating 50 that is a first distance from the projection system in a direction parallel to the optical axis of the beam 52 and projected to an optical axis parallel to the beam 52. The direction is on the second region of the grating 50 at a different distance from the projection system.

Thus, from a single relative scanning movement of beam 52 across grating 50 between beam 52 and grating 50, controller 55 obtains sufficient information to determine that each is parallel to the projection system in a direction parallel to the optical axis of beam 52. Contrast values for a plurality of regions of the grating at different distances. From this contrast value, the controller can determine the point of the maximum contrast value and thus determine the spot focus value. This procedure can be performed relatively quickly by scanning the grating 50 separately and repeatedly by the beam 52 at different positions of the substrate table WT relative to the projection system in a direction parallel to the optical axis of the beam 52.

As depicted in FIG. 10, instead of using the actuator system 60 to tilt the substrate table WT or tilting the substrate table WT in addition to using the actuator system 60, the grating 50 can also be configured such that its upper surface is opposite the substrate table The upper surface of the WT is permanently beveled. For example, the substrate 54 used to separate the grating 50 from the radiant intensity sensor 51 can be wedge shaped, as depicted in FIG. Alternatively or additionally, the grating 50 may have its own actuator to cause the grating 50 to tilt oblique.

As discussed above, the projection system can be configured to include one or more moving optics such that the radiation beam can be scanned across the substrate during formation of the image on the substrate W. In this lithography apparatus, a projection system can be used during the determination of the spot focus value to cause the beam 52 to traverse across the grating 50 for scanning. Thus, it may not be necessary to use an actuator system to move the grating 50 in a direction substantially perpendicular to the optical axis of the beam 52 to project the beam 52 onto a plurality of locations on the grating 50 for use in determining one or more Contrast value.

In this configuration, the grating 50 can be configured to be at an oblique angle to the optical axis of the beam 52 (as discussed above) such that the spot focus value can be determined without moving the grating 50 relative to the projection system.

Alternatively, the upper surface of the grating 50 can be configured to be perpendicular to the optical axis of the beam 52. In this case, an actuator system (e.g., actuator system 60 for controlling the position of the substrate table WT) can be used to move the grating 50 through the projection system in a direction parallel to the optical axis of the beam 52. A plurality of positions are obtained to obtain a plurality of contrast values for determining the spot focus value.

In the embodiments discussed above, the grating 50 of the spot focus sensor system and the radiance intensity sensor 51 can be located on the substrate table WT. This configuration may be convenient because it may permit detection of one or more radiation beams periodically projected by the projection system to determine the spot focus value without providing significant additional equipment within the lithography apparatus.

In a system having a plurality of radiation beams projected by a projection system, whenever there is a convenient suspension of production using a lithography device (eg, when loaded) When a new substrate is loaded, the spot focus value can be determined for one or more of the radiation beams. In one configuration, all radiation beams are detected each time a test is performed. Alternatively or additionally, only a proportion of the beams may be detected during some or all of the detections. In this case, the radiation beam detected in each test can be scheduled such that each radiation beam is detected at least once throughout a given number of tests.

It should also be appreciated that there is no need to provide a spot focus sensor system to the substrate table WT. Thus, for example, a separation system can be provided that can include an actuator system for moving the grating to a desired position to detect one or more radiation beams as the substrate table WT is remote from the projection system. For example, this can occur during loading of the substrate and/or unloading of the substrate from the substrate stage.

Figure 11 depicts a configuration of a grating 50 for use in a spot focusing sensor system in accordance with an embodiment of the present invention. As shown, the grating 50 includes a first grating member 50a and a second grating member 50b that are configured to be different from the projection system in a direction parallel to the optical axis of the beam 52. distance. In a single relative scan between the radiation beam 52 and the grating 50, the controller 55 can obtain respective contrast values for the first grating member 50a and the second grating member 50b.

This configuration can be beneficially used to determine the spot focus value because the contrast value can be substantially symmetrical about the best focus point as the raster changes relative to the position of the projection system. Therefore, when the best focus plane 61 is midway between the upper surface of the first grating member 50a and the upper surface of the second grating member 50b (as depicted in FIG. 11), the first grating member 50a and the second grating member 50b The contrast values for each of them will be substantially the same. Therefore, the controller 55 can The configuration determines the spot focus value by the recognition of the position of the grating 50 when the contrast value of the first grating member 50a and the contrast value of the second grating member 50b are substantially the same.

To identify this position, the controller can control an actuator system, such as any of the actuator systems discussed above, to repeatedly adjust the grating 50 in a direction parallel to the optical axis of the beam 52 relative to The position of the projection system until the contrast value of the first grating member 50a is substantially the same as the contrast value of the second grating member 50b (i.e., when the difference between the contrast values is below a certain threshold). At this time, the first grating member 50a is above the optimal focus plane 61, and the second grating member 50b is below the optimal focus plane 61.

Alternatively, the controller 55 can control the actuator system to scan the grating 50 in a direction parallel to the optical axis of the beam 52 by a position range relative to the projection system, thereby determining the first grating member 50a and the first position at each position. The contrast value of each of the two grating members 50b. From this contrast value, the controller 55 can recognize the position at which the contrast value of the first grating member 50a is substantially the same as the contrast value of the second grating member 50b. For example, controller 55 may select a location where the two contrast values are most similar. Alternatively, controller 55 may fit a curve to the relationship between the difference between the two contrast values and the distance between the grating 50 and the projection system, and select the distance corresponding to the minimum of the curve.

In one configuration, the grating 50 can be constructed such that the distance between the first grating member 50a and the second grating member 50b in the direction parallel to the optical axis of the beam 52 is of the same order of magnitude as the depth of focus of the system. In this configuration, It may be provided that the point at which the contrast value of the first grating member 50a is substantially equal to the contrast value of the second grating member 50b (i.e., at the optimal focus plane 61 is at the first grating member 50a and the second grating member 50b) In the middle of the process, neither the first grating member 50a nor the second grating member 50b are close to the optimal focus plane 61. At the best focus plane 61, the contrast value can vary minimally for a given change in position, and thus can be relatively sensitive to noise in the system, as discussed above. Therefore, since the first grating member 50a and the second grating member 50b are configured to be away from the optimal focus plane 61 in this configuration, improved accuracy can be achieved.

Although the above description has been directed to a spot sensor system configured to detect a single beam 52 to determine the spot focus value of the radiation beam, the spot focus sensor system can be configured to simultaneously detect a plurality of radiations beam. For example, if the grating 50 is of a suitable size, a plurality of radiation beams can be simultaneously projected onto the grating 50. A plurality of radiant intensity sensors 51 can be provided to simultaneously determine the contrast value of each of the radiation beams projected onto the grating 50. Alternatively, the single radiation intensity sensor 51 can be configured to be able to distinguish the intensity of the radiation from each of the plurality of radiation beams that are transmitted through the grating.

Although the above description has been directed to a grating 50 (which is transmissive such that, for example, a lithography apparatus can be configured with the grating 50 provided between the projection system and the radiation intensity sensor, such that the radiation intensity sensor 51 is self-contained The use of radiation to detect radiation passing through the grating 50 is not required for this condition. For example, a reflective grating can be used. In this case, the radiation intensity sensor can be provided on the side of the same grating as the projection system to detect radiation from the radiation spot reflected from the grating. In an embodiment, the radiation intensity sensor can be installed Mounted to a projection system or otherwise incorporated into a projection system.

Although the particular embodiment has been described in the context of moving the grating 50 in a direction parallel to the optical axis of the radiation beam to provide sufficient information to determine the spot focus value, this need not be the case. In particular, or alternatively, the focus of one or more of the radiation beams can be moved in a direction parallel to the optical axis of the radiation beam to provide the same effect. Thus, all of the embodiments discussed above, in which the grating is moved in a direction parallel to the optical axis of the radiation beam, can be modified to be implemented by moving the focus of the radiation beam. The focus point of the radiation beam can be adjusted by using a focus adjustment system such as the focus adjustment system described above.

The lithography apparatus can include a position measurement system that can be used to determine the position of the spot focus sensor system relative to another device within the lithography apparatus for determination by the spot focus sensor system The spot focus value can be used to control the operation of the lithography device. For example, the system can be used to measure the position of the spot focus sensor system relative to the projection system and/or relative to the upper surface of the substrate within the lithography apparatus.

Additionally, information from the spot focus sensor system as described above can be used during subsequent procedures to project the radiation beam onto the substrate (ie, during subsequent procedures performed as part of the component fabrication method) Adjust one or more parameters of the lithography device.

Depending on the component manufacturing method, components such as a display, an integrated circuit, or any other item can be fabricated from a substrate on which a pattern has been projected.

In one embodiment, a lithography apparatus is provided, the lithography apparatus comprising: a programmable patterning element configured to provide a plurality of radiation beams; a shadow system configured to project a plurality of radiation beams onto a substrate to form respective radiation spots; and a spot focus sensor system comprising: a grating configured to cause at least a radiation beam spot One can be sequentially projected onto a plurality of different locations on the grating to perform a radiation spot focus measurement; a radiation intensity sensor configured to transmit through the grating or from the grating at a plurality of locations A radiation beam spot detects radiation intensity; and a controller configured to determine a spot focus value from the detected radiation intensity corresponding to the plurality of locations.

In an embodiment, the lithography apparatus further includes a substrate stage configured to support the substrate, wherein the grating is mounted to an upper surface of the substrate stage. In an embodiment, the lithography apparatus further includes an actuator system configured to move the substrate stage in a direction substantially perpendicular to an optical axis of the plurality of radiation beams, wherein the amount of focus at the radiation spot During the measurement, the actuator system is used to move the grating relative to the radiation beam spot such that the radiation beam spot is projected onto a plurality of different locations on the grating. In an embodiment, the projection system is configured such that it can scan a plurality of radiation beams across the substrate in a direction substantially perpendicular to the optical axis of the radiation beam; and during the focus measurement of the radiation spot, the projection The system is used to project a spot of the radiation beam onto a plurality of different locations on the grating. In one embodiment, the controller is configured to determine a contrast value of a difference between a maximum detected radiation intensity and a minimum detected radiation intensity of at least one region of the grating comprising the plurality of different portions, and using at least one The contrast value is used to determine the spot focus value. In one embodiment, the contrast value is determined based on the following equation: Where Cv is the contrast value, I _max is the maximum detected radiation intensity of the region of the grating, and I _min is the minimum detected radiation intensity of the region of the grating. In an embodiment, the lithography apparatus further includes a focus adjustment system configured to control a position of a focus point of the radiation beam for deriving the spot in a direction substantially parallel to an optical axis of the radiation beam; Wherein the controller is configured to determine a respective contrast value of one or more regions of the grating for different positions of the focus point of the radiation beam, and determine the spot focus from the determination of the position of the focus point corresponding to the maximum contrast value value. In one embodiment, the controller is configured to determine respective contrast values for one or more regions of the grating, the surface of the grating being in an optical axis substantially parallel to the plurality of radiation beams in one or more regions Different locations in the direction, and the controller is configured to determine the spot focus value from a determination of the position of the surface of the grating in a direction substantially parallel to the optical axis of the plurality of radiation beams corresponding to the maximum contrast value . In an embodiment, the controller is configured to determine a spot focus value from a position corresponding to a highest contrast value determined from the detected radiation intensity. In an embodiment, the controller is configured to determine a contrast value at at least three different positions in a direction substantially parallel to an optical axis of the plurality of radiation beams to fit a curve to the contrast value and the corresponding position The relationship between the points and the position of the spot is determined from the position corresponding to the maximum value of the curve. In an embodiment, the lithography apparatus includes an actuator system configured to move the grating in a direction substantially parallel to an optical axis of the plurality of radiation beams; and wherein the contrast value is in the direction A single zone of the grating is determined at different locations. In an embodiment, the lithography apparatus includes an actuator system configured to move the grating in a direction substantially perpendicular to an optical axis of the plurality of radiation beams; and wherein the surface of the grating is configured to The optical axes of the plurality of radiation beams are at an oblique angle, and the contrast values are determined for different regions of the grating. In one embodiment, the surface of the grating is substantially parallel to the upper surface of the substrate stage; the actuator system is configured to control the substrate stage such that when a plurality of radiation beams are projected onto the substrate, the upper surface of the substrate table is substantially vertical The optical axis of the plurality of radiation beams, and when the plurality of radiation beams are projected onto the grating, the upper surface of the substrate stage is at an oblique angle to the optical axes of the plurality of radiation beams; and the contrast value is determined for each of the different regions of the grating. In one embodiment, the grating comprises a first grating component and a second grating component, the first grating component and the second grating component being disposed at different respective positions in a direction substantially parallel to an optical axis of the plurality of radiation beams And the controller is configured to determine the first contrast value and the second contrast value for the regions of the grating in each of the first grating component and the second grating component, respectively, and compare the first contrast value with the second contrast Value to determine the spot focus value. In an embodiment, the lithography apparatus further includes an actuator system configured to adjust a position of the grating relative to the projection system in a direction substantially parallel to an optical axis of the plurality of radiation beams; and wherein The controller is configured to determine the spot focus value from the identification of the position of the raster when the first contrast value is substantially the same as the second contrast value. In an embodiment, the lithography apparatus further includes a focus adjustment system configured to control a position of a focus point of the radiation beam for deriving the spot in a direction substantially parallel to an optical axis of the radiation beam; Wherein the controller is configured to determine the spot focus value from the identification of the position of the focus point of the radiation beam when the first contrast value is substantially the same as the second contrast value. In an embodiment, the controller is configured to repeatedly adjust the position by comparing the first contrast value with the second contrast value until the difference between the first contrast value and the second contrast value is below a certain The position is identified by the limit. In an embodiment, the controller is configured to adjust the position and determine the plurality of first contrast values and the second contrast value by determining a range of positions for each of the first contrast value and the second contrast value The position is identified by identifying a position at which the first contrast value is substantially the same as the second contrast value. In one embodiment, the grating is transmissive and disposed between the projection system and the radiation intensity sensor. In an embodiment, the grating is reflective and the radiance intensity sensor is mounted to the projection system. In an embodiment, the spot focusing system is configured to simultaneously determine individual spot focus values for a plurality of radiation beam spots.

In one embodiment, a method for measuring spot focus of a radiation beam in a lithography apparatus is provided, the lithography apparatus comprising: a programmable patterning element configured to provide a plurality of radiation beams; and a projection a system configured to project a plurality of radiation beams onto a substrate to form respective radiation spots, the method comprising: sequentially projecting at least one of the radiation beam spots onto a plurality of different locations on the grating; The radiation intensity of the radiation beam reflected by the grating or from the grating is transmitted from a plurality of locations; and the spot focus value is determined from the detected radiation intensity corresponding to the plurality of locations.

In one embodiment, the lithography apparatus includes a substrate stage configured to support the substrate and the grating is mounted to an upper surface of the substrate stage; and the method further includes using an actuator system to focus the measurement at the radiation spot The substrate stage is moved in a direction substantially perpendicular to the optical axes of the plurality of radiation beams such that the radiation beam spots are projected onto a plurality of different locations on the grating. In one embodiment, during the radiation spot focus measurement, the projection system is configured to scan the radiation beam spot across a plurality of different locations on the grating. In one embodiment, the method includes determining a contrast value of a difference between the maximum detected radiation intensity and the minimum detected radiation intensity for at least one region of the grating including the plurality of different portions, and using at least one contrast value In order to determine the spot focus value. In an embodiment, the contrast value is determined based on: Where Cv is the contrast value, I _max is the maximum detected radiation intensity of the region of the grating, and I _min is the minimum detected radiation intensity of the region of the grating. In one embodiment, the method includes determining a respective contrast value of one or more regions of the grating, the surface of the grating being in a direction substantially parallel to an optical axis of the plurality of radiation beams in the one or more regions Different spot positions; and determining the spot focus value from the position of the surface of the grating in a direction substantially parallel to the optical axis of the plurality of radiation beams corresponding to the maximum contrast value. In one embodiment, the method includes determining a spot focus value from a position of a surface of the grating corresponding to a highest contrast value determined from the detected radiation intensity. In one embodiment, the method includes determining a contrast value of at least three different locations of a surface of the grating in a direction substantially parallel to an optical axis of the plurality of radiation beams; fitting a curve to the contrast value and the corresponding position The relationship between the points; and determining the spot focus value from the position corresponding to the maximum value of the curve. In one embodiment, the method includes using an actuator system to move the grating in a direction substantially parallel to an optical axis of the plurality of radiation beams; and determining a single region of the grating at different locations in the direction Contrast value. In one embodiment, the method includes using an actuator system to move the grating in a direction substantially perpendicular to an optical axis of the plurality of radiation beams, wherein the surface of the grating is configured to form an optical axis with the plurality of radiation beams Bevel angle; and determine the contrast value for each distinct zone of the raster. In one embodiment, the method includes: using an actuator system to control the substrate stage such that when a plurality of radiation beams are projected onto the grating, the upper surface of the substrate stage is at an oblique angle to the optical axes of the plurality of radiation beams, wherein the grating The surface is substantially parallel to the upper surface of the substrate stage; and the contrast value is determined for each distinct region of the grating. In one embodiment, the grating comprises a first grating component and a second grating component, the first grating component and the second grating component being disposed at different respective positions in a direction substantially parallel to an optical axis of the plurality of radiation beams And the method includes determining a first contrast value and a second contrast value for each of the regions of the grating in each of the first grating component and the second grating component, and comparing the first contrast value with the second contrast value to determine Spot focus value. In an embodiment, the method further comprises: using an actuator system to adjust a position of the grating relative to the projection system in a direction substantially parallel to an optical axis of the plurality of radiation beams; and from the first contrast value and the second The spot focus value is determined by the identification of the position of the grating when the contrast values are substantially the same. In one embodiment, the method includes repeatedly adjusting the position of the grating using the actuator system based on the comparison of the first contrast value to the second contrast value until the difference between the first contrast value and the second contrast value is low The position of the raster is identified at a certain threshold. In one embodiment, the method includes: identifying a position of the grating by using an actuator system to move the grating by determining a range of positions for which each of the first contrast value and the second contrast value is; and The first contrast value and the second contrast value identify positions at which the first contrast value and the second contrast value are substantially the same. In one embodiment, the method includes simultaneously determining respective spot focus values for the plurality of radiation beam spots. In one embodiment, a method of fabricating a component is provided, the method of fabricating a method comprising: measuring a spot of a radiation beam of at least one of a plurality of radiation beams in a lithography apparatus using the method described herein; and using the determined The spot focus value controls at least one parameter of the lithography device to control the projection of the plurality of radiation beams onto the substrate.

Although reference may be made specifically to the use of lithography devices in IC fabrication herein, it should be understood that the lithographic devices described herein may have other applications, such as manufacturing integrated optical systems, for magnetic domain memory. Lead to detection patterns, flat panel displays, liquid crystal displays (LCDs), thin film heads, and more. Those skilled in the art should understand that in the context of the content of such alternative applications, any use of the terms "wafer" or "die" herein is considered synonymous with the more general term "substrate" or "target portion". . The substrates referred to herein may be processed before or after exposure, for example, in a coating development system (typically applying a resist layer to the substrate and developing the exposed resist), metrology tools, and/or inspection tools. . Where applicable, the disclosure herein may be applied to such and other substrate processing tools. In addition, the substrate can be processed more than once, for example, to create a multi-layer IC, such that the term "substrate" as used herein may also refer to a substrate that already contains multiple processed layers.

The term "lens", when permitted by the context of the context, may refer to any of a variety of types of optical components, including refractive, diffractive, reflective, magnetic, electromagnetic, and electrostatic optical components, or combinations thereof.

The lithography device can also be of the type in which the substrate is infiltrated with relative A liquid of high refractive index (eg, water) to fill the space between the final device of the projection system and the substrate. The wetting liquid can also be applied to other spaces in the lithography apparatus, for example, the space between the patterned element and the first device of the projection system. Infiltration techniques are well known in the art for increasing the numerical aperture of a projection system.

Further embodiments in accordance with the present invention are provided in the following numbered items:

CLAIMS 1. A lithography apparatus comprising: a programmable patterning element configured to provide a plurality of radiation beams; a projection system configured to project the plurality of radiation beams onto a substrate Forming respective radiation spots; and a spot focus sensor system comprising: a grating configured to cause at least one of the radiation beam spots to be sequentially projected onto the grating a portion for performing a radiation spot focus measurement; a radiation intensity sensor configured to detect radiation from the radiation beam spot reflected from or reflected from the grating at the plurality of locations Intensity; and a controller configured to determine a spot focus value from the detected radiation intensity corresponding to the plurality of locations.

2. The lithography apparatus of clause 1, further comprising a substrate stage configured to support the substrate, wherein the grating is mounted to an upper surface of the substrate stage.

3. The lithography apparatus of clause 2, further comprising an actuator system, The actuator system is configured to move the substrate stage in a direction substantially perpendicular to an optical axis of the plurality of radiation beams, wherein the actuator system is operative relative to a radiation spot focus measurement The radiation beam spot moves the grating such that the radiation beam spot projects onto a plurality of different locations on the grating.

4. The lithography apparatus of any of the preceding clause, wherein the projection system is configured such that it can cause the plurality of radiation beams to traverse in a direction substantially perpendicular to one of the optical axes of the radiation beams The more the substrate is scanned; and during a radiation spot focus measurement, the projection system is used to project the radiation beam spot onto a plurality of different locations on the grating.

5. The lithography apparatus of any of the preceding clause, wherein the controller is configured to determine a maximum detected radiation intensity and a minimum detective for at least one region of the grating comprising a plurality of the different portions A contrast value of one of the differences between the measured radiances is used, and the at least one contrast value is used to determine the spot focus value.

6. The lithography apparatus of clause 5, wherein the contrast value is determined based on the following formula: Where Cv is the contrast value, I _max is the maximum detected radiation intensity of the region of the grating, and I _min is the minimum detected radiation intensity of the region of the grating.

7. The lithography apparatus of clause 5 or 6, further comprising a focus adjustment system configured to be substantially parallel to the radiation beam Controlling, in one of the optical axes, a position of a focus point of the radiation beam for deriving the spot; and wherein the controller is configured to determine one of the gratings for different positions of the focus of the radiation beam or The respective spot contrast values of the plurality of zones are determined from one of the positions of the focus point corresponding to the maximum contrast value to determine the spot focus value.

8. The lithography apparatus of clause 5 or 6, wherein the controller is configured to determine respective contrast values for one or more regions of the grating, wherein the surface of the grating is in the one or more regions Substantially parallel to different respective locations in one of the optical axes of the plurality of radiation beams, and the controller is configured to be substantially parallel to the plurality of radiation beams corresponding to the maximum contrast value One of the positions of the surface of the grating in the direction of the optical axes is determined to determine the spot focus value.

9. The lithography apparatus of clause 7 or 8, wherein the controller is configured to determine the spot focus value from a position corresponding to a highest contrast value determined from the detected radiation intensities.

10. The lithography apparatus of clause 7 or 8, wherein the controller is configured to determine a contrast value at at least three different locations in the direction substantially parallel to the optical axes of the plurality of radiation beams And fitting a curve to a relationship between the contrast values and the corresponding positions, and determining the spot focus value from a position corresponding to a maximum value of the curve.

11. The lithography apparatus of any of clauses 8 to 10, comprising an actuator system configured to be substantially parallel to the optical axes of the plurality of radiation beams Moving the grating in the direction; and Wherein the contrast values are determined for a single region of the grating at different locations in the direction.

12. The lithography apparatus of any of clauses 8 to 11, comprising an actuator system configured to be substantially perpendicular to one of the optical axes of the plurality of radiation beams Moving the grating upward; and wherein the surface of the grating is configured to be at an oblique angle to the optical axes of the plurality of radiation beams, and the contrast values are determined for different regions of the grating.

13. The lithography apparatus of any of clauses 8 to 12, when attached to the item 3, wherein: the surface of the grating is substantially parallel to the upper surface of the substrate stage; the actuator system Configuring to control the substrate stage such that when the plurality of radiation beams are projected onto the substrate, the upper surface of the substrate stage is substantially perpendicular to the optical axes of the plurality of radiation beams, and when the plurality of radiation beams The upper surface of the substrate stage is angled with the optical axes of the plurality of radiation beams when projected onto the grating; and the contrast values are determined for different regions of the grating.

14. The lithography apparatus of clause 5 or 6, wherein the grating comprises a first grating component and a second grating component, the first grating component and the second grating component being disposed substantially parallel to the plurality of radiation beams And the respective controllers are configured to determine the first for the region of the grating in each of the first grating component and the second grating component, respectively; a contrast value and a second contrast value, and comparing the first contrast value with the second contrast value The spot focus value is determined.

15. The lithography apparatus of clause 14, further comprising an actuator system configured to adjust the grating relative in a direction substantially parallel to one of the optical axes of the plurality of radiation beams At the location of the projection system; and wherein the controller is configured to determine the spot focus value from one of the locations of the raster when the first contrast value is substantially the same as the second contrast value.

16. The lithography apparatus of clause 14, further comprising a focus adjustment system configured to control the source for deriving the spot in a direction substantially parallel to the optical axis of the radiation beam a location of the focus point of the radiation beam; and wherein the controller is configured to identify one of the positions of the focus point of the radiation beam from the first contrast value being substantially the same as the second contrast value The spot focus value is determined.

17. The lithography apparatus of clause 15 or 16, wherein the controller is configured to repeatedly adjust the position to the first contrast value by comparing the first contrast value to the second contrast value The position is identified by the difference between the second contrast value being below a certain threshold.

18. The lithography apparatus of clause 15 or 16, wherein the controller is configured to adjust the position by determining a range of positions for each of the first contrast value and the second contrast value And identifying the position from the plurality of first contrast values and the second contrast value identifying the position when the first contrast value is substantially the same as the second contrast value.

19. The lithography apparatus of any of the preceding clause, wherein the grating is transmissive and disposed between the projection system and the radiation intensity sensor.

The lithography apparatus of any of clauses 1 to 18, wherein the grating is reflective and the radiant intensity sensor is mounted to the projection system.

The lithography apparatus of any of the preceding clauses, wherein the spot focusing system is configured to simultaneously determine respective spot focus values of the plurality of the radiation beam spots.

22. A method for measuring spot focus of a radiation beam in a lithography apparatus, the lithography apparatus comprising: a programmable patterning element configured to provide a plurality of radiation beams; and a projection system Configuring to project the plurality of radiation beams onto a substrate to form respective radiation spots; the method comprising: sequentially projecting at least one of the radiation beam spots onto a plurality of gratings Detecting radiation intensity at a plurality of locations through the grating or from the grating reflected by the grating; and determining a spot from the detected radiation intensity corresponding to the plurality of locations Focus value.

23. The method of clause 22, wherein the lithography apparatus comprises a substrate stage configured to support the substrate, and the grating is mounted to an upper surface of the substrate stage; and the method further comprises using System is focused on a radiant light During the focal measurement, the substrate stage is moved in a direction substantially perpendicular to one of the optical axes of the plurality of radiation beams such that the radiation beam spot is projected onto a plurality of different locations on the grating.

24. The method of clause 22 or 23, wherein during a radiation spot focus measurement, the projection system is configured to scan the radiation beam spot across a plurality of different locations on the grating.

The method of any one of clauses 22 to 24, comprising: determining between a maximum detected radiation intensity and a minimum detected radiation intensity for at least one region of the grating comprising a plurality of the different portions a difference value of the difference; and using the at least one contrast value to determine the spot focus value.

26. The method of clause 25, wherein the contrast value is determined based on: Where Cv is the contrast value, I _max is the maximum detected radiation intensity of the region of the grating, and I _min is the minimum detected radiation intensity of the region of the grating.

27. The method of clause 25 or 26, comprising: determining respective contrast values for one or more regions of the grating, wherein the surface of the grating is substantially parallel to the plurality of regions in the one or more regions a respective different position in one of the optical axes of the radiation beam; and one of the surfaces of the grating in a direction substantially parallel to the optical axes of the plurality of radiation beams corresponding to the maximum contrast value The position is used to determine the spot focus value.

28. The method of clause 27, comprising determining the spot focus value from the location of the surface of the grating corresponding to the highest contrast value determined from the detected radiation intensities.

29. The method of clause 27, comprising: determining a contrast value of at least three different locations of the surface of the grating in a direction substantially parallel to the optical axes of the plurality of radiation beams; Fitting a relationship between the contrast values and the corresponding positions; and determining the spot focus value from a position corresponding to a maximum value of the curve.

The method of any one of clauses 27 to 29, comprising: using an actuator system to move the grating in a direction substantially parallel to the optical axes of the plurality of radiation beams; The contrast values are determined for a single zone of the grating at different locations in the direction.

The method of any one of clauses 27 to 29, comprising: using an actuator system to move the grating in a direction substantially perpendicular to one of the optical axes of the plurality of radiation beams, wherein the grating The surface is configured to be at an oblique angle to the optical axes of the plurality of radiation beams; and the contrast values are determined for respective different regions of the grating.

The method of any one of clauses 27 to 29, when attached to the item 23, the method comprising: using the actuator system to control the substrate stage such that when the plurality of radiation beams are projected onto the grating The upper surface of the substrate stage is at an oblique angle to the optical axes of the plurality of radiation beams, wherein the surface of the grating is The upper surface is qualitatively parallel to the substrate stage; and the contrast values are determined for different regions of the grating. The method of clause 25 or 26, wherein the grating comprises a first grating component and a second grating component, the first grating component and the second grating component being disposed substantially parallel to the plurality of radiation beams And a different position in one of the optical axes; and the method includes determining a first contrast value and a second contrast for each of the regions of the grating in each of the first grating component and the second grating component And comparing the first contrast value to the second contrast value to determine the spot focus value.

34. The method of clause 33, further comprising: using an actuator system to adjust the position of the grating relative to the projection system in a direction substantially parallel to one of the optical axes of the plurality of radiation beams; The spot focus value is determined by identifying one of the positions of the raster when the first contrast value is substantially the same as the second contrast value.

35. The method of clause 34, comprising: repetitively adjusting the position of the grating using the actuator system based on the comparison of the first contrast value and the second contrast value until the first contrast value is The position of the grating is identified by the difference between the second contrast values below a certain threshold.

36. The method of clause 34, comprising: identifying, by using the actuator system, moving the grating by determining a range of positions for which each of the first contrast value and the second contrast value is for The position of the grating; and The position is determined from the plurality of first contrast values and the second contrast value when the first contrast value is substantially the same as the second contrast value.

The method of any one of clauses 22 to 36, comprising simultaneously determining respective spot focus values of the plurality of the radiation beam spots.

38. A method of fabricating a component, comprising: measuring a spot of the radiation beam of at least one of a plurality of radiation beams in a lithography apparatus using the method of any one of clauses 22 to 37; and using The detected spot focus value controls at least one parameter of the lithography device to control the projection of the plurality of radiation beams onto a substrate.

Although the specific embodiments of the invention have been described above, it is understood that the invention may be practiced otherwise than as described. For example, the present invention can take the form of a computer program containing one or more sequences of machine readable instructions configured to perform the methods as disclosed above; or a computer readable material storage medium (eg, a semiconductor) Memory, disk or CD) with this computer program stored in it.

The above description is intended to be illustrative, and not restrictive. Therefore, it will be apparent to those skilled in the art that the present invention may be modified without departing from the scope of the appended claims.

1‧‧‧ lithography device

2‧‧‧ substrate table

3‧‧‧ Positioning components

4‧‧‧ Individual controllable self-emissive contrast elements/individual controllable devices/programmable patterned elements

5‧‧‧Frame

7‧‧‧Actuator/motor

8‧‧‧Rotating frame/rotary frame

9‧‧‧Removable optics

10‧‧‧ axis

11‧‧‧Motor/First Actuator System

12‧‧‧Lens/projection system

13‧‧‧Pore structure

14‧‧‧Projection System / Field Lens

15‧‧‧Frame

17‧‧‧Substrate

18‧‧‧Projection System / Imaging Lens

19‧‧‧Alignment/level sensor

21‧‧‧Array

30‧‧‧Segmented mirror

40‧‧‧radiation beam expander

41‧‧‧ positive lens / first lens

42‧‧‧ positive lens / second lens

43‧‧‧hard support frame

44‧‧‧Second actuator system / second actuator

45‧‧‧ Controller

46‧‧‧ optical axis

50‧‧‧Raster

50a‧‧‧First grating component

50b‧‧‧second grating component

51‧‧‧radiation intensity sensor

52‧‧‧radiation beam/focus beam

52'‧‧‧radiation beam

53‧‧‧Chromium strips

54‧‧‧Substrate

55‧‧‧ Controller

60‧‧‧Actuator system

61‧‧‧Best focus plane

A1‧‧‧ area

A2‧‧‧ area

A3‧‧‧ area

A11‧‧‧ area

A12‧‧‧ area

A13‧‧‧ area

A14‧‧‧Area

A21‧‧‧Area

A22‧‧‧Area

A23‧‧‧Area

A24‧‧‧ area

A31‧‧‧Area

A32‧‧‧Area

A33‧‧‧Area

A34‧‧‧Area

B1‧‧‧First beam set/beam

B2‧‧‧Second beam collection/beam

B3‧‧‧ Third beam set/beam

P‧‧‧ pitch

W‧‧‧Substrate

WT‧‧‧ substrate table

1 depicts components of a lithography apparatus in accordance with an embodiment of the present invention; FIG. 2 depicts a top view of components of the lithography apparatus of FIG. 1 in accordance with an embodiment of the present invention; FIG. a highly schematic perspective view of the components of the lithography apparatus; 4 depicts a schematic top view of a projection onto a substrate by a lithography apparatus according to FIG. 3, in accordance with an embodiment of the present invention; FIG. 5 depicts a configuration of a system for controlling focus, in accordance with an embodiment of the present invention; 6 schematically depicts a configuration of a spot focus sensor system in accordance with an embodiment of the present invention; FIG. 7 depicts an expected output of a radiation intensity sensor that may be used in an embodiment of the present invention; Configuration of a sensor system of one embodiment of the present invention; FIGS. 9 and 10 depict changes in the configuration of a spot focus sensor system in accordance with an embodiment of the present invention; and FIG. 11 depicts an implementation in accordance with the present invention An example of a spot focus sensor system.

50‧‧‧Raster

51‧‧‧radiation intensity sensor

52‧‧‧radiation beam/focus beam

52'‧‧‧radiation beam

53‧‧‧Chromium strips

54‧‧‧Substrate

55‧‧‧ Controller

P‧‧‧ pitch

Claims (13)

A lithography apparatus comprising: a programmable patterning element configured to provide a plurality of radiation beams; a projection system configured to project the plurality of radiation beams onto a substrate to form each And a spot focusing sensor system, comprising: a grating configured to cause at least one of the radiation beam spots to be sequentially projected onto a plurality of different portions of the grating To perform a radiation spot focus measurement; a radiation intensity sensor configured to detect radiation intensity from the radiation beam spot reflected by the grating or from the grating at the plurality of locations; And a controller configured to determine a spot focus value from the detected radiation intensity corresponding to the plurality of locations, wherein the controller is configured to target the grating including the plurality of the different portions At least one zone to determine a contrast value of a difference between the maximum detected radiation intensity and the minimum detected radiation intensity, and using the at least one contrast value to determine the spot focus value, wherein the control Configuring to determine respective contrast values of one or more regions of the grating, wherein the surface of the grating is in substantially parallel to the plurality of radiation beams in the one or more regions Different locations in one of the axes, and the controller is configured to be substantially parallel to the plurality of radiation beams The spot focus value is determined by determining one of the positions of the surface of the grating corresponding to the maximum contrast value in the direction of the axis. The lithography apparatus of claim 1, further comprising a substrate stage configured to support the substrate, wherein the grating is mounted to an upper surface of the substrate stage. The lithography apparatus of claim 2, further comprising an actuator system configured to move the substrate stage in a direction substantially perpendicular to an optical axis of the plurality of radiation beams, wherein During the radiation spot focus measurement, the actuator system is configured to move the grating relative to the radiation beam spot such that the radiation beam spot is projected onto a plurality of different locations on the grating. The lithography apparatus of any one of claims 1 to 3, wherein the projection system is configured such that it can cause the plurality of radiation beams to traverse in a direction substantially perpendicular to one of the optical axes of the radiation beams The more the substrate is scanned; and during a radiation spot focus measurement, the projection system is used to project the radiation beam spot onto a plurality of different locations on the grating. The lithography apparatus of claim 1, further comprising a focus adjustment system configured to control the radiation beam for deriving the spot in a direction substantially parallel to one of the optical axes of the radiation beam a location of a focus point; and wherein the controller is configured to determine respective contrast values for one or more regions of the grating for different locations of the focus point of the radiation beam, and from corresponding to a maximum contrast value One of the positions of the focus point is determined To determine the spot focus value. The lithography apparatus of claim 5, wherein the controller is configured to determine the spot focus value from a position corresponding to a highest contrast value determined from the detected radiation intensities. The lithography apparatus of claim 5, wherein the controller is configured to determine a contrast value at at least three different positions in the direction substantially parallel to the optical axes of the plurality of radiation beams, such that a curve The relationship between the contrast values and the corresponding positions is fitted, and the spot focus value is determined from a position corresponding to the maximum value of the curve. A lithography apparatus as claimed in claim 1, comprising an actuator system configured to move the grating in a direction substantially parallel to the optical axes of the plurality of radiation beams; and wherein The contrast values are determined for a single region of the raster at different locations in the direction. The lithography apparatus of claim 1, comprising an actuator system configured to move the grating in a direction substantially perpendicular to one of the optical axes of the plurality of radiation beams; and wherein The surface of the grating is configured to be at an oblique angle to the optical axes of the plurality of radiation beams, and the contrast values are determined for different regions of the grating. The lithography apparatus of claim 1, wherein: the surface of the grating is substantially parallel to the upper surface of the substrate stage; the actuator system is configured to control the substrate stage such that the plurality The upper surface of the substrate stage is substantially perpendicular to the optical axes of the plurality of radiation beams when the radiation beam is projected onto the substrate, and the upper portion of the substrate stage when the plurality of radiation beams are projected onto the grating The surface is at an oblique angle to the optical axes of the plurality of radiation beams; and the contrast values are determined for different regions of the grating. The lithography apparatus of claim 1, wherein the grating comprises a first grating component and a second grating component, the first grating component and the second grating component being disposed in the light substantially parallel to the plurality of radiation beams a different position in one of the axes; and the controller is configured to determine a first contrast value and a region for the region of the grating in each of the first grating component and the second grating component, respectively And a second contrast value, and comparing the first contrast value with the second contrast value to determine the spot focus value. A method for measuring spot focus of a radiation beam in a lithography apparatus, the lithography apparatus comprising: a programmable patterning element configured to provide a plurality of radiation beams; and a projection system Configuring to project the plurality of radiation beams onto a substrate to form respective radiation spots; the method comprising: sequentially projecting at least one of the radiation beam spots onto a plurality of different portions of a grating Detecting radiation intensity from the radiation beam spot reflected by the grating or from the grating at the plurality of locations; Determining a spot focus value from the detected radiation intensity corresponding to the plurality of portions, wherein the method further comprises determining a maximum detected radiation intensity for at least one region of the grating including the plurality of the different portions a contrast value of a difference between the minimum detected radiation intensities, and using the at least one contrast value to determine the spot focus value; and determining a respective contrast value of one or more regions of the grating, in the one or The surface of the grating in the plurality of regions is at a different position in a direction substantially parallel to one of the optical axes of the plurality of radiation beams, and is substantially parallel to the optical axes of the plurality of radiation beams The spot focus value is determined by determining one of the positions of the surface of the grating corresponding to the maximum contrast value in the direction. A method of fabricating a component, comprising: measuring a focus of the radiation beam spot of at least one of a plurality of radiation beams in a lithography apparatus using the method of claim 12; and using the detected spot focus value Controlling at least one parameter of the lithography device to control the projection of the plurality of radiation beams onto a substrate.