阅读说明：本技术 反射镜阵列 (Reflection mirror array ) 是由 M·M·L·施特格侯 刚天 M·尤塞菲莫格哈德丹 于 2018-03-08 设计创作，主要内容包括：一种反射镜阵列,所述反射镜阵列中的至少一些反射镜包括反射表面和从与所述反射表面相反的表面延伸的臂,其中所述反射镜阵列还包括支撑结构,所述支撑结构设置有多个感测设备,所述感测设备配置成测量所述感测设备和从所述反射镜延伸的臂之间的间隙。(A kind of reflection mirror array, at least some of reflection mirror array reflecting mirror includes reflecting surface and the arm from the surface extension opposite with the reflecting surface, wherein the reflection mirror array further includes support construction, the support construction is provided with multiple sensor devices, and the sensor device is configured to measure the sensor device and from the gap between the arm that the reflecting mirror extends.)

1. a kind of reflection mirror array, at least some of described reflection mirror array reflecting mirror include reflecting surface and from it is described anti- The arm that the opposite surface of reflective surface extends, wherein the reflection mirror array further includes support construction, the support construction is provided with Multiple sensor devices, the sensor device are configured to measure the sensor device and between the arm that the reflecting mirror extends Gap.

2. reflection mirror array according to claim 1, wherein the sensor device be configured to measure the sensor device and Gap between the end of the arm of the reflecting mirror.

3. reflection mirror array according to claim 2, wherein magnet and inductive material are arranged in the arm of the reflecting mirror At least some of end.

4. reflection mirror array according to claim 3, wherein at least some of described sensor device includes multiple vortex Sensor.

5. a kind of system, including reflection mirror array according to any preceding claims, and further include processor, it is described Processor is configured to receive the sensor device and associated reflecting mirror when EUV radiation is incident on the reflection mirror array Arm between the gap measured, the processor is configured to the gap that will be measured and do not enter when EUV radiation The gap being previously measured when being mapped on the reflection mirror array is compared to provide gap measure of the change result.

6. system according to claim 5, wherein the processor be configured to by gap measure of the change result with previously obtained The gap measure of the change result obtained is compared.

7. system according to claim 5, wherein the processor be configured to using incident radiation power and it is described between Known relation between gap variation determines the power for the radiation being incident on the reflecting mirror.

8. system according to claim 7, wherein the known relation is expressed as a model, the model considers institute State the length of absorption of the reflecting mirror to radiation of reflection mirror array, the thermal expansion coefficient of the arm and the arm.

9. system according to claim 7, wherein the known relation includes indicating strong for multiple and different incident radiations The data of the gap variation of degree being stored.

10. a kind of lithographic equipment, comprising:

Irradiation system is configured to adjust radiation beam；

Support construction, is configured to support patterning device, and the patterning device can be assigned in the cross section of radiation beam In radiation beam pattern to form patterned radiation beam；

Substrate table is configured to keep substrate；With

Optical projection system is configured to project to the patterned radiation beam on the substrate,

Wherein the irradiation system includes reflection mirror array according to claim 1.

11. a kind of lithographic equipment, comprising:

Irradiation system is configured to adjust radiation beam；

Support construction, is configured to support patterning device, and the patterning device can be assigned in the cross section of radiation beam Radiation beam pattern is given to form patterned radiation beam；

Substrate table is configured to keep substrate；With

Optical projection system is configured to project to the patterned radiation beam on the substrate,

Wherein the irradiation system includes system according to claim 5, wherein the lithographic equipment further includes that setting exists Sensor on the substrate table, wherein the processor is configured to that the sensor device acquisition of the reflection mirror array will be used Measurement result is compared with the measurement result obtained using the sensor on the substrate table.

12. lithographic equipment according to claim 11, wherein the lithographic equipment further includes that setting is formed in the pattern Sensor in the support construction of device, and wherein the processor is configured to set using the sensing of the reflection mirror array The standby measurement result obtained is carried out with the measurement result obtained using the sensor in the support construction of the patterning device Compare.

13. a kind of method of the radiant power at measurement reflection mirror array, the reflection mirror array includes at least some reflecting mirrors, At least some reflecting mirrors include reflecting surface and the arm from the surface extension opposite with the reflecting surface, the reflecting mirror Array further includes the support construction for being provided with multiple sensor devices；

Wherein, the method includes use the sensor device measure the sensor device and from the reflecting mirror extend arm it Between gap.

14. according to the method for claim 13, wherein the measurement when not having EUV radiation to be incident on the reflection mirror array The gap, measures the gap when EUV radiation is incident on the reflection mirror array, and by the gap measured into Row is relatively to provide gap measure of the change result.

15. according to the method for claim 14, wherein the method also includes use the power of incident radiation and it is described between Known relation between gap variation determines the power for the radiation being incident on the reflecting mirror.

Technical field

The present invention relates to a kind of reflection mirror arrays and a kind of method for measuring radiant power.The reflection mirror array can be with structure At a part of lithographic equipment.

Background technique

Lithographic equipment is a kind of machine for being configured to for desired pattern being applied on substrate.For example, lithographic equipment can For in the manufacture of integrated circuit (IC).Lithographic equipment will can for example come from the pattern of patterning device (for example, mask) It projects on radiation-sensitive materials (resist) layer of setting on substrate.

The radiation wavelength that lithographic equipment is used to project a pattern on substrate has determined the spy that can be formed over the substrate The minimum dimension of sign.Lithographic equipment using EUV radiation (electromagnetic radiation with the wavelength within the scope of 4-20nm) can be used for It is formed on the substrate than conventional lithographic equipment (electromagnetic radiation that the conventional lithographic equipment can be for example 193nm using wavelength) Smaller feature.

The EUV radiation used by lithographic equipment is generated by the source that for example can be the source plasma generation with laser (LPP).Come It can change over time from the amount of the power output of EUV radiation source.If the EUV radiation from EUV radiation source is defeated Power out is too high, then this may damage the component of lithographic equipment.If the power of EUV radiation is too small, this can be dropped The speed that low lithographic equipment can operate, thus reduce per hour by lithographic equipment exposure substrate number (this is properly termed as giving birth to Yield).It is therefore desirable for the power of EUV radiation can be measured, because this measurement allows correspondingly to adjust EUV radiation source.

Summary of the invention

It can be desirable to providing one kind not by the method for the measurement radiant power of teaching in prior art, and provide a kind of configuration At the reflection mirror array of offer radiant power measurement.

According to the first aspect of the invention, at least some of a kind of reflection mirror array, the reflection mirror array are provided Reflecting mirror includes reflecting surface and the arm from the surface extension opposite with the reflecting surface, wherein the reflection mirror array also wraps Support construction is included, the support construction is provided with multiple sensor devices, and the sensor device is configured to measure the sensor device And from the reflecting mirror extend arm between gap.

Sensor device and the temperature for passing through reflecting mirror and arm from the gap between the arm that reflecting mirror extends are determining.Reflecting mirror and The temperature of arm by the power of the radiation of mirror absorption in turn by being determined.Therefore, measuring the gap allows measurement to be incident on The power of radiation on reflecting mirror.

Sensor device can be configured to measure the gap between the end of the arm of the sensor device and the reflecting mirror.

Magnet and inductive material can be set in the end of at least some of the arm of the reflecting mirror.

Magnet and inductive material can be formed from different materials.Alternatively, magnet and inductive material may include phase Same material.

At least some of described sensor device may include multiple eddy current sensors.

Reflection mirror array can further include actuator, and the actuator is configured to for reflecting mirror to be moved to desired direction.

The actuator can be electromagnet.

According to the second aspect of the invention, a kind of system is provided, including the reflection mirror array according to first aspect, It and further include processor, the processor is configured to receive to sense when EUV radiation is incident on the reflection mirror array to set The gap measured between the arm of standby and associated reflecting mirror, the processor are configured to the gap that will be measured It is compared with the gap being previously measured when EUV radiation does not impinge on the reflection mirror array to provide gap variation Measurement result.

Gap measure of the change result can advantageously indicate the power for the radiation being incident on reflection mirror array.

The processor can be configured to by gap measure of the change result and the gap measure of the change result that had previously obtained into Row compares.

It is advantageous that this allows to measure the changed power for the radiation being incident on the reflecting mirror of reflection mirror array.Power becomes Changing measurement can be measured in a manner of relative value, without determining absolute power level.

The processor can be configured to true using the known relation between the power of incident radiation and gap variation It is incorporated into the power for the radiation being mapped on the reflecting mirror.

The known relation can be expressed as a model, and the model considers the reflecting mirror pair of the reflection mirror array The absorption of radiation, the thermal expansion coefficient of the arm and the arm length.

Known relation may include the data being stored for indicating the gap for multiple and different intensity of incident radiation and changing.

The optional feature of the second aspect of the present invention can be combined with the optional feature of the first aspect of the present invention.

According to the third aspect of the invention we, a kind of lithographic equipment is provided, comprising: irradiation system is configured to adjust radiation Beam；Support construction, is configured to support patterning device, and the patterning device can assign in the cross section of radiation beam Radiation beam pattern is to form patterned radiation beam；Substrate table is configured to keep substrate；And optical projection system, being configured to will be described Patterned radiation beam projects on the substrate, wherein the irradiation system includes described according to the first aspect of the invention Reflection mirror array.

The third aspect of the present invention can be combined with the optional feature of the first aspect of the present invention.

According to the fourth aspect of the invention, a kind of lithographic equipment is provided, comprising: irradiation system is configured to adjust radiation Beam；Support construction, is configured to support patterning device, and the patterning device can assign in the cross section of radiation beam Radiation beam pattern is to form patterned radiation beam；Substrate table is configured to keep substrate；And optical projection system, being configured to will be described Patterned radiation beam projects on the substrate, wherein the irradiation system includes described according to the second aspect of the invention System, wherein the lithographic equipment further includes the sensor being arranged on the substrate table, wherein the processor be configured to by The measurement result obtained using the sensor device of the reflection mirror array and the survey obtained using the sensor on the substrate table Amount result is compared.

The fourth aspect of the present invention can be combined with the optional feature of the second aspect of the present invention.

The system can further include the sensor being arranged in the support construction of the patterning device.The processing Device can be configured to the measurement result that the sensor device of the reflection mirror array will be used to obtain and formed using the pattern fill The measurement result that sensor in the support construction set obtains is compared.

According to the fifth aspect of the invention, a kind of method for measuring the radiant power at reflection mirror array is provided, it is described Reflection mirror array includes at least some reflecting mirrors, at least some reflecting mirrors include reflecting surface and from the reflecting surface The arm that opposite surface extends, the reflection mirror array further includes the support construction for being provided with multiple sensor devices；Wherein, described Method include measured using the sensor device sensor device and from the reflecting mirror extend arm between gap.

Sensor device and the temperature for passing through reflecting mirror and arm from the gap between the arm that reflecting mirror extends are determining.Reflecting mirror and The temperature of arm by the power of the radiation of mirror absorption in turn by being determined.Therefore, measuring the gap allows measurement to be incident on The power of radiation on reflecting mirror.

Gap can be measured when no EUV radiation is incident on reflection mirror array.Reflection can be incident in EUV radiation Gap is measured when on lens array.The gap measured can be compared to provide gap measure of the change result.

The method can further include carrying out gap measure of the change result with the gap measure of the change result previously obtained Compare.

The method can further include being determined using the known relation between the power of incident radiation and gap variation It is incident on the power of the radiation on the reflecting mirror.

The known relation can be expressed as a model, and the model considers reflecting mirror to the absorption of radiation, described The length of the thermal expansion coefficient of arm and the arm.

Known relation may include the data being stored for indicating the gap for multiple and different intensity of incident radiation and changing.

The method can further include identifying the damage to the reflecting mirror of reflection mirror array using gap measure of the change result Wound.

The reflection mirror array may be constructed a part of lithography system.The method can further include being changed using gap Measurement result identifies the local pollution to the radiation collector of lithography system.

The feature of the fifth aspect of the present invention can be combined with the feature of other aspects of the invention.

Detailed description of the invention

The embodiment of the present invention is only described by way of example referring now to the schematic figures of accompanying, in attached drawing In:

Fig. 1 depicts the lithography system including radiation source and lithographic equipment of embodiment according to the present invention；

Fig. 2 depicts the mirror assembly for constituting a part of the embodiment of the present invention；

Fig. 3 depicts mirror assembly, and reflecting mirror is oriented deviation balance orientation or balance direction (equilibrium orientation)；

Fig. 4 is depicted at balance orientation but EUV radiation is incident on the mirror assembly on reflecting mirror；

Fig. 5 depicts the measurement result obtained using the embodiment of the present invention；With

Fig. 6 depicts the EUV radiation reflected when executing the measurement of Fig. 5 from the collector of lithographic equipment.

Specific embodiment

Fig. 1 shows the lithography system according to an embodiment of the invention including reflection mirror array.Lithography system packet Include radiation source S O and lithographic equipment LA.Radiation source S O is configured to generate extreme ultraviolet (EUV) radiation beam B.Lithographic equipment LA includes: Irradiation system IL, is configured to support the support construction MT of patterning device MA (such as mask), optical projection system PS and is matched It is set to the substrate table WT of support substrate W.Irradiation system IL is configured to before radiation beam B is incident on patterning device MA Adjust radiation beam B.Optical projection system is configured as projecting to radiation beam B (patterning by mask MA now) on substrate W.Substrate W may include the pattern being previously formed.In this case, lithographic equipment will be patterned into radiation beam B with previously on substrate W The pattern of formation is aligned.

Radiation source S O, irradiation system IL and optical projection system PS can be constructed and arranged to allow they and outside It is environmentally isolated.The gas (such as hydrogen) of subatmospheric pressure can be provided in radiation source S O.It can be in irradiation system Vacuum is provided in IL and/or optical projection system PS.It can be provided in irradiation system IL and/or optical projection system PS and be far below atmospheric pressure Pressure under a small amount of gas (such as hydrogen).

Radiation source S O shown in Fig. 1 is the radiation source for being properly termed as the type in the source plasma generation with laser (LPP).Swash Light device 1 (such as can be CO₂Laser) it is arranged to deposit to energy in fuel via laser beam 2, such as emit from fuel The tin (Sn) that device 3 provides.Although mentioning tin in the following description, any suitable fuel can be used.Fuel can example Liquid form in this way, and may, for example, be metal or alloy.Fuel transmitter 3 may include nozzle, and the nozzle is configured to Along tin of the locus guiding towards plasma formation region 4 for example in the form of drop.Laser beam 2 is in plasma formation region It is incident on tin at 4.Laser energy deposition generates plasma 7 into tin at plasma formation region 4.In plasma Ion deactivation and compound period, emit from plasma 7 and radiate, including EUV radiation.

EUV radiation is received by near-normal incidence formula radiation collector 5 (sometimes more generally referred to as normal incidence radiation collector) Collection and focusing.Collector 5 can have multilayered structure, be arranged to reflection EUV radiation (for example, the phase with such as 13.5nm Hope the EUV radiation of wavelength).Collector 5 can have oval configuration, and there are two oval focuses for the configuration tool.First is burnt Point can be at plasma formation region 4, and the second focus can be at intermediate focus 6, as described below.

Laser 1 can be separated with radiation source S O.In this case, laser beam 2 can be by means of beam delivery system (not shown) is transmitted to radiation source S O from laser 1, the beam delivery system include for example suitable directional mirror and/or Beam expander, and/or other optical devices.Laser 1 and radiation source S O can be considered as radiating system together.

Radiation beam B is formed by the radiation that collector 5 reflects.Radiation beam B is focused at point 6 to form plasma formation region 4 image is used as the virtual radiation source of irradiation system IL.Point 6 where radiation beam B is focused is properly termed as intermediate focus. Radiation source S O is arranged so that intermediate focus 6 is located at or near the opening 8 in the enclosed construction 9 of radiation source.

Radiation beam B is passed into irradiation system IL from radiation source S O, and irradiation system IL is configured to adjust radiation beam. Irradiation system IL includes facet field reflector apparatus 10 and may include facet pupil reflector apparatus 11.Facet field reflecting mirror Device 10 is the reflection mirror array being made of the reflecting mirror that can be controlled respectively.The reflecting mirror of the array and associated actuator It is properly termed as mirror assembly together with sensor device.The direction (as described further below) of controller CT control reflecting mirror. Facet field reflector apparatus 10 and facet pupil reflector apparatus 11 together for radiation beam B provide desired cross-sectional shape and Desired angle intensity distribution.Radiation beam B passes through and is incident on from irradiation system IL and formed by the pattern that support construction MT is kept On device MA.Patterning device MA reflection radiation beam B simultaneously makes radiation beam B pattern.In addition to 10 He of facet field reflector apparatus Except facet pupil reflector apparatus 11 or facet field reflector apparatus 10 and facet pupil reflector apparatus 11 are replaced, irradiation is The IL that unites may include other reflecting mirrors or device.

After the reflection from patterning device MA, patterned radiation beam B enters optical projection system PS.Optical projection system Including multiple reflecting mirrors 13,14, the mirror arrangement projects on the substrate W kept by substrate table WT at by radiation beam B.It throws Shadow system PS, which can apply radiation beam, reduces the factor, to form the corresponding spy that there is feature to be less than on patterning device MA The image of sign.For example, the 4 diminution factor can be applied for.Although optical projection system PS has in Fig. 1 there are two reflecting mirror 13,14, But optical projection system may include any number of reflecting mirror (such as six reflecting mirrors).

Radiation source S O shown in FIG. 1 may include component (not shown).For example, spectral filter can be set in radiation source In.Spectral filter can be substantially transmission to EUV radiation, but to the radiation of other wavelength (such as infra-red radiation) base It is to stop in sheet.

Fig. 2 schematically depicts the mirror assembly 19 of facet field device 10 (this is the example of reflection mirror array).Instead The outer surface 22 for penetrating mirror 20 is reflexive to EUV radiation, such as with by the alternate multiple layers of multilayer knot formed of reflectivity Structure.The thickness of layer is selected such that provide the constructive interference of the EUV radiation reflected from layer boundary.

Arm 24 extends from the surface 26 opposite with reflecting surface 22 of reflecting mirror.Surface 26 is properly termed as the rear table of reflecting mirror Face.Arm 24 be connected to the rear surface 26 of reflecting mirror center (although it can connect in the rear surface of reflecting mirror it is a certain its It point at).Connection between arm 24 and reflecting mirror 20 is rigid, so that the movement of arm will lead to the movement of reflecting mirror.Leaf spring 28 also extend from the rear surface of reflecting mirror 20.Connector 34 receives leaf spring 28, and is connected to support construction 30 in turn.Connector 34 may, for example, be the ring being welded in support construction 30.Connector 34 can be metal.Leaf spring 28 can for example weld or It is bolted to connector 34.Connector 34 can have known thermal resistance.

Therefore, leaf spring is connected to support construction 30 via connector 34 and thus supports reflecting mirror 20.Arm 24 is not attached to Support construction 30, but pass through the opening 32 in support construction.It is practical although depicting two leaf springs 28 in fig. 2 On, four leaf springs can be set, each leaf spring extends in different directions.For example, two leaf springs 28 can be spaced in the y-direction Connector 34 is fixed at the position opened.Other two leaf spring (not describing) can connect at position spaced apart in the x-direction To connector 34.

Although reflecting mirror 20 is connected to support construction 30 using four leaf springs by discribed embodiment, can provide The connection of other forms.For example, the leaf spring of different number can be set.Can provide various forms of elastic connections (for example, certain The spring of kind other forms).Similarly, the connector can have other shapes and/or configuration.In embodiment, it connects Device can be omitted.

Reflecting mirror 20 and arm 24 are resiliently biased to balance orientation by leaf spring 28.In this embodiment, balance orientation is corresponding It is basically parallel to the surface of support construction in the reflecting surface 22 of reflecting mirror 20, and corresponds to arm 24 and passes through in support construction The center of opening 32.However, in other embodiments, reflecting mirror 20 can be biased to a certain other balance orientation by leaf spring 28. When power is applied on arm 24, such as when pushing down on swing arm in fig. 2, leaf spring 28 be bent and allow reflecting mirror 20 orientation or Direction changes.When power is removed, leaf spring 28 makes reflecting mirror 20 return to its balance orientation (and make arm 24 return to its and balance orientation).

Magnet 40 is located at the end of arm 24.Inductance or 42 layers of inductive material are set on magnet 40 (for example, attached using screw It is connected to magnet or is glued on magnet).Magnet 40 allows to exert a force on arm 24, and arm and reflecting mirror 20 are moved to difference Direction.Inductive material 42 allows to measure the direction of arm 24 (and reflecting mirror 20).It may expect that magnet 40 has high intensity, because The intensity of magnet will be determined for the power (as described below) for being applied to arm 24 to constant current in electromagnet.Magnet 40 can be such as It is formed by SmCo.It is desirable that, 42 layers of inductive material have high irritability, because which dictates that being surveyed using eddy current sensor The signal strength (as described below) of amount.Inductive material 42 may, for example, be AlMgMn alloy.In general, magnet 40 and inductive material 42 It may include any suitable material.In embodiment, magnet 40 and inductive material 42 may include that homogenous material (such as is both Magnetic is the ferrous material or ferrous material of induction again).

Four electromagnet 44a-d are supported by the second support construction 46.Second support construction 46, which can connect to support, to reflect The support construction 30 of mirror 20, to provide single integrated support structure.Electromagnet is depicted from top with sectional view in fig. 2b 44a-d.As can be seen that two electromagnets 44a and 44c are separation in y-direction, and two electromagnets 44b and 44d are in x It is separation on direction.In order to make it easy to understand, using cartesian coordinate in the present specification, and used using common photoetching Example, wherein the direction of radiation beam is the direction z.It will be appreciated, however, that this is not intended to limit the invention to mirror assembly phase For the specific direction of radiation beam.Electromagnet 44a-d and magnet 40 on arm 24 are the examples of mirror actuator.It can be used The mirror actuator of other forms, such as some other form of electromagnetic actuators, or the permanent magnetism moved by mechanical actuator Body.

Eddy current sensor 48a-d is equipped in the end of each electromagnet 44a-d.Eddy current sensor 48a-d is retouched in fig. 2 c It draws and there is configuration identical with electromagnet 44a-d.Eddy current sensor 48a-d is the example of sensor device.It can be used The sensor device of its form.For example, sensor device may include optical sensor, which is arranged to measurement from magnetic The position of the radiation beam of the surface reflection of body 40 and/or phase.

Controller CT (referring to Fig. 1) conveys electrical current to electromagnet 44a-d, which is selected to generate magnetic field, described Desired power is applied to magnet 40 by magnetic field, so that magnet is moved to desired position.This causes arm 24 to rotate and makes to reflect Mirror 20 is moved to desired direction.The example that reflecting mirror is rotated to desired orientation using electromagnet is depicted in Fig. 3.Show at this In example, electric current flows through the first electromagnet 44a along the direction in the magnetic field for generating attraction magnet 40.Meanwhile electric current is worn in opposite direction Third electromagnet 44c is crossed, to generate the magnetic field of repulsive magnets 40.In addition, side of the electric current along the magnetic field for generating attraction magnet 40 To flowing through the second electromagnet 44b.Finally, electric current flows through the 4th electromagnet 44d along the direction in the magnetic field for generating repulsive magnets 40.Make Keep magnet mobile along positive y-direction as depicted and positive x direction (although this is invisible in Fig. 3) with the power on magnet 40. The movement causes leaf spring 28 to be bent and reflecting mirror 20 is rotated.Eddy current sensor 48a-d sense inductive material 42 in by magnetic The vortex of field induction.Therefore eddy current sensor 48a-d can determine the position of inductive material, therefore can determine the position of arm 24 It sets.This allows for the direction for calculating reflecting mirror 20.

The mirror assembly 19 described in Fig. 2 is a part of reflection mirror array.It is anti-that reflection mirror array can be facet field Penetrate lens device 10 (as depicted in fig. 1).In use, as being further noted that above, it may be desirable in facet pupil reflecting mirror Specific irradiation mode is formed at device 11.This can by select facet field reflector apparatus 10 reflecting mirror 20 direction with So that radiation beam is directed toward the certain desired position at facet pupil reflector apparatus 11.For example, reflecting mirror 20 can be determined It, to form dipole modes, or can be oriented at two regions directed radiation on facet pupil reflector apparatus 11 Four regions directed radiation on facet pupil reflector apparatus are to form quadrupole mode.Controller CT (referring to Fig. 1) can With the direction of the reflecting mirror 20 for controlling the array.Controller CT can be transported to associated with reflecting mirror 20 by control The electric current of electromagnet 44a-d realize above-mentioned control.Controller CT can receive to be passed from vortex associated with reflecting mirror The measurement result of sensor 48a-d, and can be used as these measurement results when control is transported to the electric current of electromagnet 44a-d Feedback.

Fig. 4 is schematically depicted and the identical equipment described in Fig. 2 and Fig. 3.However, in figure 2 and figure 3, not having On incident to reflecting mirror 20, and in Fig. 4, on incident to reflecting mirror.In this embodiment, it is incident on reflecting mirror 20 On radiation include EUV radiation (schematically being depicted by arrow).Although reflecting mirror 20 reflects EUV radiation, it is not Full-reflector, but reflect about 60% incident EUV radiation.Therefore, a large amount of EUV radiation is absorbed and is caused anti-by reflecting mirror 20 Penetrate the heating of mirror.Arm 24 is metal (such as steel, copper or alloy), and is thermally connected to reflecting mirror.Arm 24 can be for example soldered Or it is soldered to reflecting mirror 20.Thermal connection between arm 24 and mirror 20 can make the arm quilt when reflecting mirror is heated to given temperature It is heated to substantially the same temperature.

The length of arm is several centimetres (for example, between 5 to 10 centimetres, for example, about 7 centimetres).Because arm 24 is by metal It constitutes, so it has significant thermal expansion coefficient.Therefore, when 24 heating of arm, arm expansion.The expansion of arm 24 makes 40 He of magnet Inductive material 42 is mobile towards eddy current sensor 48a-d and electromagnet 44a-d.Arm 24 due to being not secured to support construction 30 and Free extension.

The expansion of arm 24 is determined by the temperature of arm.The temperature of arm 24 is determined by the temperature of reflecting mirror 20 in turn, and is reflected The temperature of mirror 20 is determined by the amount of the EUV radiation of mirror absorption.The amount for the EUV radiation that reflecting mirror 20 absorbs is depended on and is incident on The power of EUV radiation on reflecting mirror.Therefore, the expansion for measuring arm 24, which provides to depend directly on, to be incident on reflecting mirror 20 The output of the power of EUV radiation.It can be surveyed by the variation at the interval between measurement inductive material 42 and eddy current sensor 48 Measure the expansion of arm 24.This can be referred to as the variation in the gap 60 between measurement inductive material 42 and eddy current sensor 48.Gap 60 instructions are at any between eddy current sensor 48a and 48c, therefore dotted line is by comprising to guide eyes.

Eddy current sensor can be used to measure the gap 60 between inductive material 42 and eddy current sensor 48a-d.Processing The output signal from eddy current sensor 48a-d can be used to measure gap 60 in device PR, is incident on reflection to allow to measure The power of EUV radiation on mirror 20.Although processor PR is depicted as the entity discrete with controller CT, processor can be with Constitute a part of controller.Processor PR can execute the calculating being further described above.

Gap 60 between inductive material 42 and eddy current sensor 48a-d can be by that will export from two eddy current sensors Signal be added together rather than subtract them determine (subtraction of eddy current signal be used for measure inductive material the direction x and y move It is dynamic).For example, can be added together by the signal of eddy current sensor 48a and the 48c output separated in y-direction with generation pair The measurement result in the gap 60 between inductive material 42 and eddy current sensor.By the eddy current sensor 48b that separates in the x direction and The signal of 48d output can be added together to obtain the second gap measurement.Any of these measurements in gap 60 All it is enough the power for allowing to measure the EUV radiation being incident on reflecting mirror 20.Accordingly, there exist some redundancies.The redundancy can have Allow to execute clearance measurement sharply, for example, even if one in eddy current sensor out of service.Alternatively, using the direction x It can be used for generating average measurements with the direction the y eddy current sensor 48a-d measurement result obtained.This can advantageously be improved Due to the accuracy of the clearance measurement that influences to reduce and obtain of the single eddy current sensor of for example non-correct measurement.

Eddy current sensor 48a-d generates alternating electromagnetic field.These alternating electromagnetic fields induce vortex in inductive material 42, The vortex is opposite with the alternating electromagnetic field generated by sensor 48a-d.Sensor detects the formation of secondary electromagnetic field, thus really Determine about the proximity of inductive material 42 or the information of degree of closeness.

In embodiment, gap 60 (Fig. 2) can be measured when no EUV radiation is incident on reflecting mirror 20, then when Gap 60 (Fig. 4) is then measured when EUV radiation is incident on reflecting mirror.Then the variation in gap 60 can be determined.Gap 60 Variation is directly determined by the power for the EUV radiation being incident on reflecting mirror 20.

In an embodiment of the present invention, the EUV radiation of about 200W can be incident on facet field reflector apparatus 10, greatly About 80W can be absorbed by facet field reflector apparatus.As a result, arm 24 occurs significantly to expand, to provide between several microns The variation of gap 60.This allows with the EUV radiation power of reasonable accuracy measurement incidence.

When arm 24 and reflecting mirror 20 are in its equilbrium position (as Fig. 2 and Fig. 4 describe), simplest form can be executed Clearance measurement.In the position, inductive material 42 is essentially symmetrically located at the direction the x direction eddy current sensor 48b, 48d and y and is vortexed Between sensor 48a, 48c.As a result, only indicating inductive material 42 and currents sensing from the signal that eddy current sensor 48a-d is exported Gap 60 between device 48a-d, and do not influenced by the direction x of inductive material or the displacement of the direction y.This allows with direct or simple Single mode determines gap.

However, when all reflecting mirrors 20 of array and associated arm 24 are all in its equilbrium position, in facet pupil At reflector apparatus 11 radiate it is final be distributed by not with the feelings in high accuracy and quality are used for as used in lithographic equipment The irradiation mode projected a pattern on substrate under condition is corresponding.Therefore, if to be in equilbrium position in all reflecting mirrors 20 In the case where execute clearance measurement, then can without using lithographic equipment come expose production substrate in the case where carry out gap survey Amount.Clearance measurement can be executed for example during the initial setting of lithographic equipment.Clearance measurement can be for example by pre- timing Between execute after section.In one example, clearance measurement can execute daily, weekly or after several weeks.In one example, Clearance measurement can execute after a batch of substrate has been exposed and before the substrate of next batch has been exposed. One batch can be made of 20 to 30 substrates (such as 25 substrates).

Clearance measurement can execute multiple reflecting mirrors 20 of reflection mirror array.This allows for determining across reflecting mirror battle array The EUV radiation power measurement of multiple positions of column.Compared with single EUV radiation power measurement, this is favourable, because it is distinguished The space localized variation of totality (generalised) variation and EUV radiation power of EUV radiation power.

In embodiment, the two groups of clearance measurements carried out in different time using incident EUV radiation can be compared.For Every group of clearance measurement can compare gap and the gap seen in the case where no EUV radiation is incident on reflecting mirror Compared with to obtain gap measure of the change result twice.If the EUV spoke in second of measurement, on essentially all reflecting mirror It penetrates power and has reduced (such as lesser gap variation instruction), then the overall decline of EUV radiation source output power has occurred.If EUV radiation power at most of reflecting mirrors is held essentially constant (gap variation is essentially identical), but at the reflecting mirror of subgroup EUV radiation power variation the gap of these reflecting mirrors (variation has significantly changed) have had occurred, then this representation space is locally asked Topic.Space local problem for example can be the local pollution on collector.Similarly, if it is observed that essentially all reflecting mirror EUV power all reduce (i.e. the gap variation of those reflecting mirrors is identical), but some in reflecting mirror observe EUV radiation function Rate fall is bigger (i.e. gap variation is smaller), then this may indicate that the power of EUV radiation source generally has dropped, but furthermore Pollution there are also space local problem, on such as collector.

Fig. 5 depicts the gap measure of the change executed on facet field reflector apparatus 10 using the embodiment of the present invention As a result (scale of instruction is as unit of micron).Fig. 6 is the photo of the collector 5 of lithographic equipment, and the measurement of Fig. 5 is in the collection It is obtained in device, the power for the EUV radiation that the photo instruction is reflected from collector.It can use to execute the time of clearance measurement It is restricted and (executes clearance measurement while executing other experiments measurement).Therefore, it is not directed to facet field reflector apparatus 10 Each reflecting mirror measure gap, but for reflecting mirror distribution (distributed) subgroup execute clearance measurement.So And in other embodiments, gap can be measured for the full reflection mirror of facet field reflector apparatus 10.In Fig. 5, it is Each reflecting mirror is numbered convenient for identification.

Gap is measured when on no incident to reflecting mirror.Then, when EUV radiation is incident on reflecting mirror, then Secondary measurement gap.Referring to Fig. 4, for each reflecting mirror 20, arm 24 has expansion, and this reduce inductive material 42 and currents sensings The size in the gap 60 between device 48a-d.The range of gap size variation is from less than 0.1 micron to greater than 2.5 microns.Gap 60 Variation be depicted as in Fig. 5.In Fig. 5, the small change in deeper shadow representation gap, and between shallower shadow representation The large change of gap.There is no reflecting mirror at the center of facet field reflector apparatus 10.This is because (as can be seen from Figure 6) In That position is not received by the radiation from collector 5.

Referring to Fig.1, received EUV radiation is EUV spoke by emitting from plasma 4 at facet field reflector apparatus 10 Penetrate the image of the collector 5 of irradiation.It follows that 60 measurement result of gap shown in fig. 5 should correspond to from as depicted in figure 6 The power of the EUV radiation of collector reflection.It can be seen that from the comparison of Fig. 5 and Fig. 6 and be implicitly present in this corresponding relationship.Therefore, In area 61 immediately below the center of collector 5, pollutant is had accumulated on collector, so that it no longer reflects EUV radiation, And occurs dark space in Fig. 6.Gap measurement in Fig. 5 indicates the dark space, wherein generation almost no or no The variation (for example, expansion less than 0.1 micron) in gap 60.In another example, in the right hand margin close to collector 5 Region 62 at gathered pollutant.The pollutant has reduced the power of EUV radiation, but still remains some EUV Radiation.(it is significantly less than and is receiving more in fig. 5 it may be seen that the gap in the region changes between 1 micron to 1.5 microns The gap variation observed in other positions of high power EUV radiation).In another example, the center of collector 5 just on There are a certain pollutants at the region 63 of side, but high power EUV radiation is received at the region of surface 64.Again in Fig. 5 In it is observed that wherein vary less (about 1 micron) close to the gap observed of reflecting mirror of opening, and on the area The gap variation in the region 66 of side is significantly larger (being greater than 2 microns).

As described above, the measurement executed to generate the discribed result of Fig. 5 is actually limited, and do not measure The gap 60 of all reflecting mirrors of facet field reflector apparatus 10.However, this limited measurement identification pollutant is in collector 5 On position, and additionally provide pollution level instruction (for example, pollutant weaken EUV radiation intensity).In other words It says, the power of the EUV radiation reflected by collector 5 is to allow to determine position and pollutant of the pollutant on collector 5 The mode of degree is measured.

The result obtained using gap measure of the change can be grouped together to provide to being incident on facet field reflecting mirror The measurement of total EUV radiation power on device 10.

As further described above, the measurement in gap 60 can be executed when reflecting mirror 20 and arm 24 are in its equilbrium position, Or it can be measured when reflecting mirror and arm rotation deviate its equilbrium position.The length of arm 24 is several centimetres (such as about 7 Centimetre), and the rotation of the angle of arm is a few milliradians.Therefore, its equilbrium position of arm rotation deviation will not be to inductive material 42 and whirlpool Gap between flow sensor 48a-d makes a significant impact.The measurement of output from eddy current sensor 48a-d still can be used In determining gap 60.The measurement is executed in the same manner as described above, that is, by that will come from one or more pairs of eddy current sensors The output phase of 48a and 48c, 48b and 48d are added together to measure.However, when the rotation of reflecting mirror 20 deviates its equilbrium position When, incidence angle of the EUV radiation on the reflecting mirror changes, this so influence the EUV radiation reflected by reflecting mirror ratio and by The ratio of the EUV radiation of absorption.This is because the thickness of the layer is selected to as described above, reflecting mirror includes series of layers There is provided the constructive interference of EUV radiation reflected from layer boundary, and inclined mirror will have and be presented to the increased layer of thickness The effect of EUV radiation.Since reflecting mirror 20 can change reflectivity and absorptivity in its inclination, inclined reflecting mirror is used The accuracy of the EUV radiation power measurement of acquisition will be reduced accordingly.It can be by executing the calibration of gap tilt effect and then executing Calibration is taken into account to improve the accuracy of measurement when subsequent measurement.But if when reflecting mirror is in its equilbrium position Measurement is executed, then avoids the possibility of the demand of calibration and the accuracy of measurement.By in reflecting mirror not at its equilbrium position The advantages of executing measurement and generating is that this allows to execute EUV radiation power measurement during the production of substrate exposes.This is that have Benefit, because it avoids the loss in productivity that can occur in the case where stopping substrate production to execute measurement.

Obtained by sequentially collecting the vortex output signal from each reflecting mirror as depicted in figures 5 as a result, this Cause measurement relatively slow.However, in other embodiments, can concurrently receive the signal exported from eddy current sensor.Example Such as, facet field reflector apparatus 10 includes ten groups of reflecting mirrors, and can be by simultaneously from the eddy current signal that every group of reflecting mirror exports It receives and handles.In another embodiment, multiplexer can be used to circuit sequentially by exporting from all reflecting mirrors Eddy current signal is collected the data from each reflecting mirror and is stored it in memory for subsequent processing.This seed type Arrangement for example can rapidly can collect data in less than 10 seconds (such as in about 5 seconds).

The time scale for executing the measurement of embodiment according to the present invention is significantly less than when EUV radiation is not again incident on reflection The time constant that the temperature of reflecting mirror 20 and arm 24 declines when on mirror 20.Therefore, when EUV radiation does not impinge on reflection mirror array When upper, the embodiment of the present invention can be used and obtain accurate measurement result.Under any circumstance, as explained above, work as EUV When on incident to reflection mirror array (such as during producing exposure), the embodiment of the present invention can be used and obtain measurement knot Fruit.

As explained above in conjunction with Fig. 5 and Fig. 6, the embodiment of the present invention allows to identify the pollutant on collector 5 Local accumulation.The embodiment of the present invention also allows to detect the overall reduction of the power of EUV radiation at any time.Both of which is phase To measurement result, that is, the measurement result in gap 60 to be compared with the measurement result in the gap 60 previously obtained.However, logical It crosses using the known relation between the power of incident radiation and gap variation, the embodiment of the present invention can also be used to obtain EUV spoke Penetrate the absolute measurement result of power.In embodiment, it is known that relationship includes indicating between multiple and different intensity of incident radiation The data of gap variation being stored.In embodiment, it is known that relationship is expressed as a model, and it is right which considers reflecting mirror 20 Absorption, the thermal expansion coefficient of arm 24 and the length of arm of radiation.The model is also conceivable to the radiation emitted by plasma 4 Spectrum, the thermal resistance of leaf spring 28, the length of leaf spring and its thermal expansion coefficient.By considering the known relation, between given Gap 60 measures, and can measure the power for the EUV radiation being incident on reflecting mirror 20.

Determine that the power for the EUV radiation being incident on facet field reflector apparatus 10 allows to adjust spoke using feedback control Penetrate the power of the EUV radiation of source SO output.This allows the power of EUV radiation to keep relatively high, so that can expose per hour More substrates, while ensuring that not high attend the meeting of the power of EUV radiation damages the degree of lithographic equipment.

The component that most of EUV radiation are photo-etched equipment before it reaches substrate W absorbs.This affects lithographic equipment Operation, and can correspondingly apply correction.For example, the component that EUV radiation may be projected system PS absorbs, this effect Referred to as lens heat.This may introduce distortion or deformation in the pattern being projected.The component of adjustable optical projection system To reduce this distortion.The embodiment of the present invention allows to measure the function of EUV radiation in the upstream of most of components of lithographic equipment Rate, and therefore allow more accurately to estimate the amount of absorbed EUV radiation.This allows for more accurately executing lithographic equipment Adjustment (for example, lens heating correction).

Although facet field reflector apparatus 10 (example of reflection mirror array) has 336 in the discribed embodiment of Fig. 5 A reflecting mirror, but in other embodiments, the reflection mirror array of the reflecting mirror with some other quantity can be used.If The obvious lesser amount of reflecting mirror used will then accordingly decrease and be used to measure the spatial resolution of EUV radiation power.It is similar Correspondingly increase is used to measure the spatial resolution of EUV radiation power if increasing the quantity of reflecting mirror by ground.

Referring to Fig.1, the sensor S being arranged on substrate table WT can be used for measuring by the spy of facet field reflector apparatus 10 Determine the power of the EUV radiation of the reflection of reflecting mirror 20.Sensor S can directly detect EUV radiation, or may include turning EUV It is changed to the layer of the material for the longer wavelength that can be more easily detected.Because sensor S is located at irradiation system IL, patterning device MA With the downstream of optical projection system PS, so these three elements will have an impact the EUV radiation power seen at sensor S.But It is to influence all to may be known and/or be separately measurable in each of these elements, and remove its influence from measurement. Therefore, for given reflecting mirror 20, two measurement results can be obtained.The first measurement obtained using the embodiment of the present invention The result is that the measurement result of the power for the EUV radiation being incident on reflecting mirror 20.The second measurement result obtained using sensor S It is the measurement result of the power for the EUV radiation being reflected by reflecting mirror 20 on sensor.The two measurement results allow to identify Reflecting mirror there are the problem of, such as the problem due to caused by the reduction or deterioration of the reflectivity of reflecting mirror.It is normalized at one Example in, it is contemplated that at reflecting mirror 20 normalized radiant power be 100, thus sensor S at offer radiation Power is 1.If seeing significantly lower radiant power (such as 0.5), this can be construed as to imply that the reflection of reflecting mirror Rate is decreased (radiation of reflecting mirror reflection is less, and the radiation of absorption is more).Then it can adopt remedial measures anti-to mitigate Penetrate the influence that the reflectivity of mirror reduces.For example, the irradiation mode formed using facet field reflector apparatus 10 can be modified, to subtract Any influence of the reflecting mirror deteriorated less.During the maintenance of lithographic equipment, if deterioration reflecting mirror quantity it is sufficiently high with It will affect the operation of lithographic equipment as it, then can replace facet field reflector apparatus 10.

It is previously possible the EUV radiation reflected using sensor S measurement by each reflecting mirror of facet field reflector apparatus 10 Power.But since measurement is carried out in the downstream of irradiation system IL, patterning device MA and optical projection system PS, institute It is influenced with measurement by these elements, it is thus possible to will lead to the situation of some inaccuracy.The embodiment of the present invention advantageously mentions The measurement for the EUV radiation power being incident at the reflecting mirror 20 of facet field reflector apparatus 10 is supplied, the EUV radiation power is straight It connects and is measured at those reflecting mirrors.Therefore, the shadow of the measurement not exposure system IL, patterning device MA and optical projection system PS It rings, therefore more accurate measurement can be provided.Although sensor or video camera can be provided in radiation source S O itself to monitor EUV radiation power, but this is the environment of a rather harsh, is easily contaminated.The embodiment provides at this The outside of adverse circumstances is still at the position of the first optical component (facet field reflector apparatus) outside the adverse circumstances The measurement of EUV radiation power.Therefore, the embodiment of the present invention avoids potential pollution problem, while avoiding due to being located at Potential accuracy caused by element between radiation source and the position for executing measurement is insufficient.

Lithographic equipment can include EUV radiation sensor at other positions.For example, can be at the output of irradiation system IL Sensor is set.It can be by the measurement result for using the embodiment of the present invention to obtain and from the sensor (or other sensors) Output be compared, to allow to determine related with lithographic equipment additional information.For example, being filled by comparing facet field reflecting mirror Set the EUV radiation power (as measured by using the embodiment of the present invention) at 10 and the EUV spoke at the output of irradiation system IL The power penetrated can determine the transmission (rate) of irradiation system.

The damage of reflecting mirror 20 can be by comparing the variation in the gap 60 seen for the reflecting mirror and for adjacent The variation in the gap that reflecting mirror is seen identifies.For example, if the variation in the gap 60 of reflecting mirror be significantly greater than it is adjacent anti- The variation in the gap 60 of mirror is penetrated, then this can be shown that the reflectivity of the reflecting mirror has significantly reduced and (receive nearly identical amounts with positive The adjacent mirror of EUV radiation compare, which is just absorbing more EUV radiation now).Therefore, it can identify that this is anti- Penetrating mirror is to have damaged.

The power for the EUV radiation being incident on substrate W is the output of lithographic equipment (even if per hour may be used with lithographic equipment With patterned substrate quantity) limiting factor.It is therefore generally desirable to which EUV radiation power is as high as possible.But if EUV spoke It penetrates the high power of ether to be incident on certain components of lithographic equipment, (such as protection pattern is formed certain components of lithographic equipment The pellicle of device MA) it may be damaged.Accordingly, it may be desirable to which EUV radiation source is will immediately lower than occur such as pellicle The horizontal power of parts damages operates.The embodiment provides the measurement of EUV radiation, the measurements of the EUV radiation Feedback can be used as by controller to adjust the operation of radiation source S O, EUV radiation power is thus maintained at aspiration level.This can To help to provide component of the good output without damage such as pellicle etc of lithographic equipment.

In embodiment, the present invention may be constructed a part of mask detection equipment.EUV can be used in mask detection equipment Radiation monitors the radiation reflected from mask using imaging sensor to irradiate mask.By the received figure of imaging sensor As for determining in mask with the presence or absence of defect.Mask detection equipment may include being configured as receiving from EUV radiation source EUV radiation simultaneously forms it into the optical device (such as reflecting mirror) in the radiation beam that guide to mask.Mask detection is set It is standby to may further include optical device (for example, reflecting mirror), be configured as collecting the EUV radiation reflected from mask and at Image as forming mask at sensor.Mask detection equipment may include processor, the processor be configured as analysis at It determines on mask as the image of the mask at sensor, and according to the analysis with the presence or absence of any defect.The processor can be with It is further configured to determine that whether the defects on mask detected when the lithographic equipment use has the mask can thrown Unacceptable defect is caused in image on shadow to substrate.

In embodiment, the present invention may be constructed a part of measurement equipment.The measurement equipment can be used for measuring Alignment of the pattern being projected formed in resist on substrate relative to pattern already existing on substrate.Opposite alignment This measurement, which can be referred to as, to be overlapped.Measurement equipment can be for example close to lithographic equipment, and can be used for handling lining Overlapping is measured before bottom (and resist).

Although herein, specifically being referred in the case of lithographic equipment to the embodiment of the present invention, this The embodiment of invention can be used for other equipment.The embodiment of the present invention may be constructed mask detection equipment, measurement equipment or survey Any equipment of the object of amount or processing such as chip (or other substrates) or mask (or other patterning devices) etc A part.These equipment may be generally referred to as lithography tool.Vacuum condition or environment (antivacuum) can be used in this lithography tool Condition.

Term " EUV radiation " may be considered that including wavelength within the scope of 4-20nm (such as within the scope of 13nm-14nm) Electromagnetic radiation.EUV radiation can have the wavelength less than 10nm, such as the wavelength within the scope of 4-10nm, such as 6.7nm or The wavelength of 6.8nm.

Although radiation source S O is portrayed as the source plasma generation with laser LPP by Fig. 1, any suitable source can by with In generation EUV radiation.For example, fuel (such as tin) can be converted into plasmoid to generate transmitting by using electric discharge The plasma of EUV.Such radiation source can be referred to as electric discharge and generate the source plasma (DPP).Electric discharge can be by electricity Source generates, which may be constructed a part of radiation source, or can be via electrical connection and be connected to dividing for radiation source S O Vertical entity.

Although herein can the use to lithographic equipment in ic manufacturing carried out with specific reference to should manage Solution, lithographic equipment described herein can have other application.Possible other application includes manufacture integrated optics system, magnetic domain The guidance of memory and detection pattern, flat-panel monitor, liquid crystal display (LCD), film magnetic head etc..

The embodiment of the present invention can be implemented with hardware, firmware, software or any combination thereof.The embodiment of the present invention is also It may be implemented as storing instruction on a machine-readable medium, which can be read and be held by one or more processors Row.Machine readable media may include for storing or transmitting the information in the form of machine (for example, computing device) is readable Any mechanism.For example, machine readable media may include read-only memory (ROM)；Random access memory (RAM)；Disk storage Deposit medium；Optical storage medium；Flash memory devices；Electricity, optics, acoustics or other forms transmitting signal (for example, carrying Wave, infrared signal, digital signal etc.) etc..In addition, firmware, software, routine, instruction can be described as executing herein it is certain Movement.It is understood, however, that such description is just for the sake of convenient, and such movement be actually by computing device, Processor, controller, or execute firmware, software, routine, instruction etc. or other devices generate.

Although specific embodiments of the present invention are hereinbefore described, it should be appreciated that, the present invention can with retouched The different modes stated are practiced.Description above is intended to be exemplary and not restrictive.Therefore, art technology Personnel are readily apparent that, can carry out without departing substantially from the scope of the claims set forth below to the described present invention Modification.