Patent Description:
As a protective membrane for reticles (a. masks), the typical EUV pellicles will be inherently fragile and prone to breakage because they are ultra-thin (e.g., tens of nanometers thick) and macroscopically large (e.g., ~<NUM> x <NUM>). The EUV pellicles also need to be thin due to a transmittance requirement of higher than <NUM>%. The present situation is that pellicle ruptures may occur at any step and/or location during the use and/or transport of the reticle assemblies. The transfer and/or use for printing of a reticle assembly with a ruptured EUV pellicle may result in an increased distribution of pellicle fragments throughout an EUV scanner body or other tools (e.g., mask inspection tool, pod transfer tool, etc.).

To help mitigate this problem, sensors have been incorporated into EUV scanners to detect a reticle assembly with ruptured pellicles, and windows have been added to EUV reticle transport pods to permit observation/detection of the presence of a ruptured pellicle. However, an EUV pellicle may rupture at times when unobserved (e.g., when a reticle assembly is in the reticle library), and the immediate detection of and/or techniques for preventing such ruptures are still not widely available.

<CIT> discloses: A pellicle suitable for use with a patterning device for a lithographic apparatus. The pellicle comprising at least one breakage region which is configured to preferentially break, during normal use in a lithographic apparatus, prior to breakage of remaining regions of the pellicle. At least one breakage region comprises a region of the pellicle which has a reduced thickness when compared to surrounding regions of the pellicle.

<CIT> discloses: A lithographic apparatus comprising a support structure constructed to support a patterning device and associated pellicle, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam, and a projection system configured to project the patterned radiation beam onto a target portion of a substrate, wherein the support structure is located in a housing and wherein pressure sensors are located in the housing.

The invention pursued in this application is set out in the appended set of claims.

The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the present disclosure. The dimensions of the various features or elements may be arbitrarily expanded or reduced for clarity. In the following description, various aspects of the present disclosure are described with reference to the following drawings, in which:.

The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details, and aspects in which the present disclosure may be practiced. These aspects are described in sufficient detail to enable those skilled in the art to practice the present disclosure. Various aspects are provided for devices, and various aspects are provided for methods. It will be understood that the basic properties of the devices also hold for the methods and vice versa. Other aspects may be utilized and structural, and logical changes may be made without departing from the scope that is set out in the appended set of claims. The various aspects are not necessarily mutually exclusive, as some aspects can be combined with one or more other aspects to form new aspects.

In an aspect, the present disclosure is directed to an onboard sensor assembly for real-time monitoring of EUV pellicle membrane deflections and ruptures, as set out in the appended set of claims. In particular, the sensor assembly has optical components, including a light source, a light detector, and a reflector, and sensor components, including a pressure sensor and an accelerometer. The optical and sensor components are coupled to a controller, which in turn is coupled to one or more semiconductor process tools. The sensor assembly monitors the EUV pellicle that is attached to a pellicle support frame positioned on a reticle, which are all parts of the reticle assembly.

In another aspect, the present disclosure is directed to a pellicle monitoring system for monitoring a plurality of reticle assemblies, with each reticle assembly having a reticle, an EUV pellicle, a pellicle support frame, optical components, and sensor components, for which the optical and sensor components generate signals relating to monitoring the movements and condition of the EUV pellicle. The pellicle monitoring system further includes a system controller configured to be coupled with the plurality of reticle assemblies to receive signals from their optical and sensor components, and a data storage coupled with the system controller for storing the signals received from each reticle assembly and providing threshold data for pellicle deflection limits and a maximum number of pellicle deflection cycles. The plurality of reticle assemblies may be used in a semiconductor process system for EUV lithography, and a reticle assembly can be removed when ruptured or approaching a failure/rupture event.

In another aspect, the present disclosure is directed to a method for monitoring a plurality of reticle assemblies, for which each reticle assembly has a reticle, an EUV pellicle, a pellicle support frame, optical components, and sensor components. The optical and sensor components, which may be discrete units attached to the pellicle support frame, or built into the pellicle support frame (i.e., as an integral part thereof), may generate signals relating to monitoring the movements and condition of the EUV pellicle. The method further provides a system controller configured to be coupled with the plurality of reticle assemblies for receiving signals from their optical and sensor components, and the system controller is further coupled to data storage that stores the signals received from each reticle assembly and provides threshold data for the limits of pellicle deflections and maximum permitted pellicle deflection cycles to the system controller. In the various aspects, the components of the sensor assembly, including the optical and sensor components, and the system controller may communicate, i.e., receive and transmit their signals, via wire/trace connections or wirelessly.

In a further aspect, the method may use a model-based algorithm to predict when an EUV pellicle membrane may fail and prevent further use of a potentially "failing" pellicle membrane before rupture. In addition, the method may include one of the plurality of reticle assemblies being removed from use by a semiconductor process system when the EUV pellicle for one of the plurality of reticle assemblies reaches its pellicle deflection limit or maximum number of pellicle deflection cycles, or when the EUV pellicle is ruptured.

The technical advantages of the present disclosure may include, but are not limited to:.

To more readily understand and put into practical effect the present reticle assemblies with onboard sensors designs and the methods for their use to improve the performance of semiconductor process systems, particular aspects will now be described by way of examples provided in the drawings that are not intended as limitations. The advantages and features of the aspects herein disclosed will be apparent through reference to the following descriptions relating to the accompanying drawings. Furthermore, it is to be understood that the features of the various aspects described herein are not mutually exclusive and can exist in various combinations and permutations. For the sake of brevity, duplicate descriptions of features and properties may be omitted.

<FIG> shows an exemplary extreme ultraviolet (EUV) pellicle assembly <NUM> according to an aspect of the present disclosure. In this aspect, the pellicle assembly <NUM> includes an EUV pellicle <NUM> that may be a thin film or membrane attached to a pellicle support frame <NUM>, which has a plurality of attachment members <NUM>. The EUV pellicle <NUM> may be made of a plurality of materials, including dielectric materials (e.g., SiO2, SiNx, SiC, or graphite), conductive materials (e.g., metals), and/or semiconductors (e.g., polysilicon), and maybe tens of nanometers in thickness. The present pellicle assemblies may be configured with onboard sensor assemblies, which may be part of a reticle assembly as described below and may be fixedly or removably attached to a reticle.

In another aspect, the EUV pellicle <NUM> and pellicle support frame <NUM> may be made from a single layer of material, and the EUV pellicle <NUM> formed by back etching, or the EUV pellicle <NUM> may be synthesized by a plurality of means well known to those skilled in the art, including via chemical vapor deposition, physical vapor deposition, ion beam deposition, and atomic layer deposition onto a metal catalyst, and attached to the pellicle support frame <NUM>.

<FIG> and <FIG> show representative drawings of the deflection movements of an exemplary EUV pellicle <NUM> according to various aspects of the present disclosure. As shown in <FIG>, the EUV pellicle <NUM> may be attached to a pellicle support frame <NUM> having attachment members <NUM>, which are components of a pellicle assembly <NUM>. In this aspect, the EUV pellicle <NUM> may have a downward deflection movement that produces a concave shape 202a and a displacement Z<NUM> from its neutral position. As shown in <FIG>, the EUV pellicle <NUM> may have an upward deflection movement that produces a convex shape 202b and a displacement Z<NUM> from its neutral position.

In another aspect, the amplitude of the deflection movements (i.e., displacements Z<NUM> and Z<NUM>) of the EUV pellicle <NUM> will depend, in part, on the conditions for and the types of operations being performed by the various semiconductor process tools using or handling the reticle assembly. In addition, based on an understanding of the physical stresses on a pellicle as well as ongoing data generated by the present reticle assemblies, datasets of threshold deflection limits (i.e., maximum displacements for Z<NUM> and Z<NUM>) and maximum number of pellicle deflection cycles may be available in memory devices or databases for reference by SOCs and semiconductor process systems during the monitoring of reticle assemblies.

<FIG> shows an exemplary reticle assembly <NUM> with onboard optical components, i.e., a light source <NUM> and a reflector <NUM> (e.g., corner cube mirror), from a sensor assembly that may be used to monitor the deflection movements of an EUV pellicle <NUM> according to an aspect of the present disclosure. In addition, the reticle assembly <NUM> may include a pellicle assembly <NUM> having the EUV pellicle <NUM> and a pellicle support frame <NUM> with attachment members <NUM>, which are positioned on a reticle/mask <NUM> that has a patterning <NUM>.

In this aspect, for conducting scans to monitor the EUV pellicle <NUM>, the light source <NUM> may be configured to provide a light that is directed towards the EUV pellicle <NUM> and reflected towards the reflector <NUM>, which is aligned with the light source <NUM>. When the EUV pellicle <NUM> has a neutral position, the light may have a first reflection pattern R<NUM>, and when deflected downward by a distance Z<NUM> in a concave position 302a, the light may have a second reflection pattern R<NUM>, which may result in a different angle of reflection of the light by the EUV pellicle <NUM>. Although not shown, when the EUV pellicle <NUM> is deflected upward in a convex position, the light may have a third reflection pattern. The different reflection patterns may be detected by a light detector according to various aspects of the present disclosure as described below.

In another aspect, the EUV reticle/mask <NUM> and patterning <NUM> may consist of a plurality of layers (e.g., an EUV Bragg mirror with forty (<NUM>) or more alternating silicon, molybdenum layers for the mirror elements, and tantalum-based layer for the patterned absorbing elements). The multilayers act to reflect the extreme ultraviolet light through Bragg diffraction, with the reflectance being a function of the incident angle and wavelength. In yet another aspect, the light source <NUM> may be, for example, a light emitting diode or a laser, and the reflector <NUM> may be, for example, a corner cube mirror or a pair of linear array of mirrors with offset angles of reflection designed to impart a multitude of reflections off of the pellicle membrane.

<FIG> shows an exemplary reticle assembly <NUM> with optical components including a light source <NUM>, a reflector <NUM>, and a light detector <NUM> according to another aspect of the present disclosure for monitoring an EUV pellicle. The reticle assembly <NUM> includes an EUV pellicle <NUM>, which is attached to a pellicle frame support <NUM> having attachment members <NUM>, that is attached to a reticle/mask <NUM> in a standard assembly that has a patterning <NUM>. In this aspect, the light source <NUM> (e.g., a light emitting diode (LED)), and light detector <NUM> (e.g., a photodiode), may both be coupled by a signal line <NUM> (e.g., a conventional wire bond or a subtractive process lithographically produced trace on the surface of the reticle <NUM>), to a system-on-chip (SOC) <NUM> and may be surface bonded to the reticle <NUM>. In an aspect, the SOC <NUM> may include a processor/controller such as a central processing unit (CPU), microprocessor, etc..

It should be understood that the signal line <NUM> may be replaced with short-range wireless technologies (e.g., near field communication (NFC)) and all of the various components herein may be equipped with a NFC capability, including the SOC <NUM>, which may also be in wireless communications with a semiconductor process system.

As shown in <FIG>, the light source <NUM> may emit a light ray L<NUM> that is reflected by a bottom surface of the pellicle membrane <NUM> as light R<NUM> towards a reflector <NUM> (e.g., a corner cube mirror). The light R<NUM> may be reflected by the reflector <NUM> back towards the bottom surface of the pellicle membrane <NUM> as light M<NUM> and is thereafter reflected as light R<NUM> to the light detector or photodiode <NUM>. The photodiode <NUM> converts the light R<NUM> into an electrical current/signal.

In another aspect, the signal from the photodiode <NUM> may be directed to the processor/controller (not shown) on the SOC <NUM> or a system controller of a tool (not shown) used in a semiconductor process system, and the controller determines whether: a) deflections of the pellicle membrane <NUM> from initial position are occurring, or b) a current is absent or below a current threshold indicating a rupture event. The pellicle deflections may be determined using a time-of-flight calculation performed by the controller and additional optical components may be employed.

In another aspect, if a tool (not shown) in the semiconductor process system takes control of the optical and sensor components of a reticle assembly, as set forth in the present disclosure, it will override the commands of the onboard SOC so that the monitoring of the pellicle may be optimized/synchronized with the operations of the tool; for example, an EUV scanner may command a reticle assembly to monitor/sample only when stepping (i.e., between shots).

In accordance with the present disclosure, the analysis of the displacement of a pellicle may use a finite element and/or non-linear membrane approach, which may be employed to model the relationship between the displacements and the accompanying bi-axial stress on the pellicle membrane. The pellicle membranes are subjected to repeated mechanical stresses, extreme temperature cycling, and harsh hydrogen radical environmental conditions that may result in a reduction in the strength of the pellicle membranes through embrittlement, oxidation, fracture and in some cases rupture, i.e., catastrophic failure. Regardless of the choice of pellicle membrane materials, a means for monitoring pellicle membrane deflection, as taught by the present disclosure, is advantageous for process control. The pellicle stress data that may be acquired by the present optical and sensor components may be used to anticipate/predict failures (i.e., rupture) due to pellicle membrane fatigue and prevent rupture.

In addition to the present capability to detect and determine the magnitude and direction of a pellicle membrane deflection, an analysis of the intensity of light reflected off the pellicle membrane as a function of the number of scanner shots or exposures may also be measured and used to determine changes, if any, in the pellicle membrane materials (e.g., oxidation of the polysilicon core, degradation of emissivity layer, etc.) and used as inputs to a model for predicting pellicle membrane failure. Also, information relating to changes in the pellicle membrane's optical properties may be valuable for lithographic process control, as such changes may affect the results of lithographic scans.

For example, when a measured magnitude of a deflection beyond a threshold value is detected or the maximum number of deflections is exceeded, a notification/alarm could be triggered to stop any processing using the affected reticle assembly. Similarly, when a rupture event is detected, a notification/alarm can be triggered to alert an operator, who can take appropriate action. It should be understood that the present disclosure may be effective when a reticle assembly is inside or outside of an EUV scanner; for example, if a pellicle ruptures/breaks during transport or while a reticle assembly is in a stocker, the rupture will be detected and the operator will be alerted to stop further operations or to prevent the loading of the reticle assembly with the ruptured pellicle into an EUV scanner.

<FIG> shows an exemplary reticle assembly <NUM> with optical components including a light source <NUM>, a reflector <NUM>, and a light detector <NUM> according to another aspect of the present disclosure for monitoring an EUV pellicle. The reticle assembly <NUM> includes an EUV pellicle <NUM>, which is attached to a pellicle frame support <NUM> having attachment members <NUM>, which are attached to a reticle/mask <NUM> in a standard assembly that has a patterning <NUM>.

In this aspect, the light source <NUM> may be a laser (e.g., an ultrashort pulse laser) connected to a fiber optic cable <NUM>, and light detector <NUM> may be a photodiode, both of which may be coupled by a signal line <NUM> (e.g., a conventional wire bond or a lithographically produced trace on the surface of the reticle <NUM>), to a system-on-chip (SOC) <NUM> and may be surface bonded to the reticle <NUM>. In another aspect, the optical components (i.e., the light source <NUM>, the reflector <NUM>, and the light detector <NUM>), may also be built into the pellicle frame support, which is typically fabricated from single crystal silicon.

As shown in <FIG>, in accordance with this aspect, the pellicle membrane <NUM> may have a core layer 502b with upper layer 502a and lower layer 502c. The core layer <NUM> may be formed of a silicon layer having properties of a single crystal, an amorphous or a polycrystalline with high transmittance and may be formed of a silicon layer containing boron (B), phosphorus (P), arsenic (Mo), or tungsten silicide (WSi), tantalum silicide (TaSi), and/or like materials. The center layer 502b may have a thickness of <NUM> or less and preferably has a transmittance of <NUM>% or more for an EUV exposure light of <NUM>.

In addition, the pellicle <NUM> may have the upper layer 502a and lower layer 502c for reinforcing the mechanical strength and thermal properties of the pellicle core layer 502b and protecting the pellicle membrane <NUM> from the high temperatures generated during the EUV scan process, including protecting against oxidation. In an aspect, the upper layer 502a and lower layer 502c may be formed of a metal (e.g., ruthenium (Ru), molybdenum (Mo), etc.), graphene, carbon nanotube (CNT), or metal silicide that have the required emissivity layers and are good reflectors for typical LED wavelengths, such as <NUM>, and for lasers.

<FIG> shows a top view of an exemplary reticle assembly <NUM> with a sensor assembly having optical components and sensor components according to another aspect of the present disclosure. The various elements of <FIG> may be included in a pellicle monitoring system to detect ruptured pellicle membranes and remove reticle assemblies with pellicles nearing a rupture event. The reticle assembly <NUM> includes an EUV pellicle <NUM>, which is attached to a pellicle frame support <NUM> having attachment members <NUM>, which are attached to a reticle/mask <NUM> with a pattern <NUM> in a standard assembly.

In this aspect, the optical components may include an LED light source <NUM>, a corner cube mirror reflector <NUM>, and a photodiode light detector <NUM> for optical monitoring of the EUV pellicle <NUM>. As shown in <FIG>, the LED light source <NUM>, the corner cube mirror reflector <NUM>, and the photodiode light detector may be positioned to be aligned across from each other to permit the reflection of light between them. It should be understood that the positions of the LED light source <NUM>, the corner cube mirror reflector <NUM>, and a photodiode light detector <NUM> may be relocated from those positions shown in <FIG>, provided they are sufficiently aligned to permit the reflection of light between them.

In an aspect, an onboard system on chip (SOC) <NUM> may be mounted on reticle <NUM>, and the sensor components may be provided as a separate device chip <NUM> having an accelerometer, pressure sensor, temperature sensor, etc. (not individually shown in <FIG>) that may be also mounted on the reticle <NUM>. Although not shown, the device chip <NUM> may be alternatively mounted onto the SOC <NUM>. In another aspect, a battery <NUM> may be mounted on the SOC <NUM> (not shown) or placed adjacent to and coupled with the SOC <NUM> as shown in <FIG>. In yet another aspect, an external power (i.e., a tool's power source) may be used to provide power to the SOC and onboard optical and sensor components. In a further aspect, the SOC <NUM> may be coupled with an external semiconductor process system controller <NUM>, which may be a tool's processor or a fab network/system controller, and a data storage component <NUM>, which may be a separate memory device mounted on the SOC <NUM>, a memory storage device for a tool, or a database unit for a fab network system.

<FIG> shows yet another exemplary reticle assembly <NUM> with a sensor assembly having a light source <NUM>, a pair of first and second linear array of mirrors or reflectors 714a and 714b, and a light detector <NUM> according to another aspect of the present disclosure for monitoring an EUV pellicle <NUM>. The reticle assembly <NUM> includes a standard assembly having a pellicle frame support <NUM> with attachment members <NUM> that are attached to a reticle/mask <NUM> that has a patterning <NUM>, and a SOC <NUM>.

In this aspect, the light source <NUM> (e.g., a light emitting diode (LED)), and light detector <NUM> (e.g., a photodiode), may both be coupled by a signal line <NUM> (e.g., a conventional wire bond or a lithographically produced trace on the surface of the reticle <NUM>), to a system-on-chip (SOC) <NUM> and may be surface bonded to the reticle <NUM>. It should be understood that the signal line <NUM> may be replaced with short-range wireless technologies (e.g., near field communication (NFC)) and all of the various components herein may be equipped with a NFC capability, including the SOC <NUM>, which may be in communications with a semiconductor process system.

As shown in <FIG>, in an aspect, the first and second linear array of mirrors 714a and 714b may have surfaces providing a plurality of different angles that will reflect light rays to slightly different regions of the bottom surface of the EUV pellicle membrane <NUM> with each subsequent reflection. In this aspect, the deflections of the pellicle <NUM> may be determined using a time-of-flight approach using passive optical elements (i.e., mirrors) to effect a multitude of reflections, e.g., <NUM>-<NUM> reflections, off of a pellicle membrane to make the light path length sufficiently long for measurement of a deflection (typically on the order of ~<NUM>-<NUM>) using relatively slow LED sources.

As shown in <FIG>, the light source <NUM> may emit a light ray L<NUM> that reflects from the bottom surface of the pellicle membrane <NUM> towards the first linear array of mirrors 714a as light R<NUM>. The light R<NUM> may be reflected by the first linear array of mirrors 714a as light M<NUM> back to the bottom surface of the pellicle membrane <NUM> and towards the second linear array of mirrors 714b. The second linear array of mirrors 714b reflects the light as light M<NUM> and the light is reflected back and forth between the first and second linear array of mirrors 714a and 714b as a plurality of M<NUM> and M<NUM> light rays until, at an appropriate time, the photodiode <NUM> converts a "final" light ray D<NUM> to an electrical current.

In another aspect, the current from the photodiode <NUM> may be directed to a processor (not shown) in the SOC <NUM>, or a tool (not shown) used in a semiconductor process system, to determine if: a) deflections of the pellicle membrane <NUM> from an initial position are occurring, or b) a current is absent or below a threshold indicating a rupture event.

<FIG> shows a top view of an exemplary reticle assembly <NUM> with a sensor assembly having optical components and sensor components according to another aspect of the present disclosure. The reticle assembly <NUM> includes an EUV pellicle <NUM>, which is attached to a pellicle frame support <NUM> having attachment members <NUM> that are attached to a reticle/mask <NUM> with a pattern <NUM> in a standard assembly.

In this aspect, the optical components may include an LED light source <NUM>, a first and second linear array of mirrors 814a and 814b, and a photodiode light detector <NUM> for optical monitoring of the EUV pellicle <NUM>. An onboard system on chip (SOC) <NUM> may be mounted on the reticle <NUM>. In an aspect, the sensor components may be provided as a separate device chip <NUM> having an accelerometer, pressure sensor, temperature sensor, etc. (not individually shown in <FIG>) that may be also mounted on the reticle <NUM>. Although not shown, the device chip <NUM> may be alternatively mounted onto the SOC <NUM>. In another aspect, a battery <NUM> may be mounted on the SOC <NUM> (not shown) or placed adjacent to and coupled with the SOC <NUM> as shown in <FIG>.

As shown in <FIG>, the first and second linear array of mirrors 814a and 814b may be positioned to be aligned across from each other to permit the reflection of light back and forth between them. It should be understood that the positions of the first and second linear array of mirrors 814a and 814b may be relocated from those positions shown in <FIG>, provided they are sufficiently aligned to permit the reflection of light between them. Similarly, the LED light source <NUM> may be suitably positioned to facilitate the reflection of light back and forth between the first and second linear array of mirrors 814a and 814b, and the photodiode light detector <NUM> may be suitably positioned to detect the light following an appropriate number of reflections the first and second linear array of mirrors 814a and 814b.

<FIG> shows an exemplary reticle assembly <NUM> having exemplary optical components, including a light source <NUM> and a light detector <NUM> of a sensor assembly, that are positioned in an upper portion of a pellicle frame support <NUM> in the reticle assembly <NUM>. In an aspect, the light source <NUM> and a light detector <NUM> are aligned to acquire measurements from light that is reflected from an upper surface of the pellicle <NUM>. The reticle assembly <NUM> may include various aspects and elements from the other reticle assemblies disclosed herein, including a reticle <NUM> with patterning <NUM> and a SOC <NUM>, as well as other conventional elements that are present in a reticle assembly.

In this aspect, the optical components of the light source <NUM> and light detector <NUM>), may be built into the pellicle frame support <NUM> or be discreet units attached to the pellicle frame support <NUM> to monitor the movements of EUV pellicle <NUM>. The positioning of the light source <NUM> and a light detector <NUM> in the upper portion of the pellicle frame support <NUM> may simplify the construction of the reticle assembly <NUM>.

<FIG> shows a simplified decision diagram <NUM> of an exemplary method directed to the communications between one or more reticle assemblies and devices in a semiconductor process system according to an aspect of the present disclosure. In this aspect, as shown in step/node <NUM>, a device (e.g., an EUV scanner, inspection tool, stocker, etc.) may be activated for operations in a semiconductor process system. In step <NUM>, the device may be enabled to actively monitor and control the use of the reticle assemblies. In step <NUM>, as part of the active control, the device and the reticles may be required to optimize/synchronize their clock speeds for performing various tasks (e.g., monitoring when stepping by an EUV scanner (i.e., between scans/shots).

Further to this aspect, in step <NUM>, a pellicle in a reticle assembly may rupture and be detected by the device or a SOC onboard the reticle assembly, while being monitored by a device. The detection of such a rupture may lead to, in step <NUM>, a warning signal being transmitted to the device and/or an operator.

If no rupture occurs or is detected by the device or the SOC onboard the reticle assembly, in step <NUM>, the z-direction displacements during deflections of a pellicle may be monitored and compared against data for a threshold deflection limit that may be available in a data storage <NUM>. The detection of such a deflection having a magnitude exceeding the threshold deflection limit may lead to, in step <NUM>, a warning signal being transmitted to the device and an operator.

If no deflection exceeding the threshold deflection limit is detected by the device or the SOC onboard the reticle assembly, in step <NUM>, the total number of deflections of a pellicle may be monitored and compared against data for a maximum number of deflections limit for the pellicle that may be available in a data storage <NUM>. The detection of the total number of deflections exceeding the maximum number of deflections limit may lead to, in step <NUM>, a warning signal being transmitted to the device and an operator.

If no deflection exceeding the threshold deflection limit is detected by the device or the SOC onboard the reticle assembly, in step <NUM>, the device may continue monitoring by repeating steps <NUM> through <NUM>.

In the event that step <NUM> occurs, as shown in <FIG>, the warning signal transmitted to the device or an operator may lead to a collection of operational data (e.g., type of event, the number of the deflections, acceleration/velocity information, time stamp, pressure conditions, temperature conditions, etc.) from steps <NUM>, <NUM> or <NUM> being recorded in the data storage <NUM>. Such data/information may advance a user's ability to determine the root cause of a given pellicle failure and make modifications to eliminate that failure mode, which may provide a significant competitive advantage.

In addition, in step <NUM>, the warning signal transmitted to the device or an operator may lead to the stopping of the process or operation being performed by the device, and in step <NUM>, the at-issue reticle assembly may be taken offline and removed from further use to repaired or discarded.

In another aspect, if in step <NUM>, a device is not enabled to actively control the monitoring of a reticle assembly, an onboard SOC for a reticle assembly may monitor the condition of the pellicle in a "standalone mode" in accordance with the various aspects of the present disclosure. It is understood that the SOC may be in communications with a host tool, such as an EUV scanner or inspection tool, while in the standalone mode. In step <NUM>, for example, the reticle assembly having an onboard SOC may, using one or more sensor components, determine if the reticle assembly is being moved, e.g., using an accelerometer.

If the reticle assembly is not being moved (e.g., at rest in storage or library), in step <NUM>, a monitoring frequency for the pellicle may be set at a low rate. For example, a reticle assembly sitting in a storage stocker with no movement for a month could be monitored at a low rate (e.g., 1x per minute or more). If the reticle assembly is being moved but not being used for scanning, in step <NUM>, a monitoring frequency for the pellicle may be set at a medium rate (e.g., 1x per a fraction of minute). On the other hand, a reticle assembly positioned in a critical tool, such as a scanner, would be monitored at a high frequency (e.g., 1x per second), while in printing. If the monitoring of the reticle assembly in steps <NUM> or <NUM> results in a detection of a rupture, as shown in step <NUM>, such a rupture may also lead to, in step <NUM>, a warning signal being transmitted to the device and/or an operator, as in step <NUM>.

<FIG> shows a simplified flow diagram for a further exemplary method according to a further aspect of the present disclosure. In an aspect, the present method may be able to provide monitoring of pellicles to prevent ruptures and to remove ruptured pellicles to prevent extending the contamination of a semiconductor process system with pellicle fragments and causing processing delays.

The operation <NUM> may be directed to providing a reticle assembly having a pellicle with an onboard sensor assembly, including optical and sensor components and a controller, for monitoring the condition of the pellicle.

The operation <NUM> may be directed to providing a connection between one or more devices in a semiconductor operations system and the onboard sensor assembly to monitor the pellicle and exchange data.

The operation <NUM> may be directed to providing data storage coupled with the semiconductor operations system that stores threshold data for pellicle deflection limits and maximum pellicle deflection cycles for the reticle assembly.

The operation <NUM> may be directed to removing the reticle assembly from further use by the semiconductor operations system when the pellicle deflection limit or maximum pellicle deflection cycles is reached, or if the pellicle is ruptured.

It will be understood that any specific property described herein for a specific reticle assembly or specific sensor assembly may also generally hold for any of the other reticle assembly or sensor assembly described herein. It will also be understood that any specific property described herein for a specific method may generally hold for any of the other methods described herein. Furthermore, it will be understood that for any tool, system, or method described herein, not necessarily all the components or operations described will be enclosed in the tool, system, or method, but only some (but not all) components or operations may be enclosed.

To more readily understand and put into practical effect the present reticle assemblies and sensor assemblies, they will now be described by way of examples. For the sake of brevity, duplicate descriptions of features and properties may be omitted.

The term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or operation or group of integers or operations but not the exclusion of any other integer or operation or group of integers or operations. This definition also applies to variations on the term "comprising" such as "comprise" and "comprises".

The term "coupled" (or "connected") herein may be understood as electrically coupled or as mechanically coupled, e.g., attached or fixed or attached, or just in contact without any fixation, and it will be understood that both direct coupling or indirect coupling (in other words: coupling without direct contact) may be provided.

The terms "and" and "or" herein may be understood to mean "and/or" as including either or both of two stated possibilities.

Claim 1:
A sensor assembly comprising:
optical components comprising a light source (<NUM>), a light detector (<NUM>), and a reflector (<NUM>);
sensor components comprising a pressure sensor and an accelerometer; and
a controller coupled to the optical components and the sensor components, the controller being further coupled to one or more semiconductor process tools;
wherein the sensor assembly is configured to monitor a pellicle (<NUM>) attached to a pellicle support frame (<NUM>) positioned on a reticle (<NUM>),
wherein the light source (<NUM>) is configured to direct light towards the pellicle (<NUM>) and the light reflected by the pellicle (<NUM>) toward the reflector (<NUM>);
wherein the reflector (<NUM>) is configured to receive the light from the pellicle (<NUM>) and reflect the light back toward the pellicle (<NUM>), the light being further reflected by the pellicle (<NUM>) toward the light detector (<NUM>); and
wherein the light detector (<NUM>) is configured to detect the light and generate signals that are transmitted to the controller, wherein the controller determines whether a movement of the pellicle (<NUM>) exceeds its threshold deflection limit or a maximum number of pellicle deflection cycles based on the signal, or whether the pellicle (<NUM>) is ruptured based on the signal.