Passive resonator, a system incorporating the passive resonator for real-time intra-process monitoring and control and an associated method

Disclosed is a resonator made up of three sections (i.e., first, second and third sections) of a semiconductor layer. The second section has an end abutting the first section, a middle portion (i.e., an inductor portion) coiled around the first section and another end abutting the third section. The first and third sections exhibit a higher capacitance to the wafer substrate than the second section. Also disclosed are a process control system and method that incorporate one or more of these resonators. Specifically, during processing by a processing tool, wireless interrogation unit(s) detect the frequency response of resonator(s) in response to an applied stimulus. The detected frequency response is measured and used as the basis for making real-time adjustments to input settings on the processing tool (e.g., as the basis for making real-time adjustments to the temperature setting(s) of an anneal chamber).

BACKGROUND

1. Field of the Invention

The embodiments of the invention generally relate to intra-process monitoring and control and, more particularly, to embodiments of a passive resonator capable of being wirelessly interrogated during processing by a processing tool, a system incorporating the passive resonator for real-time intra-process monitoring and control, and an associated method.

2. Description of the Related Art

As lithographic geometries are reduced for each successive semiconductor process generation, the effects of process variability have become significant first order issues. Designers are faced with creating tradeoffs between timing margin, power, and performance. Tighter process controls enable lower power, higher performance, and/or higher yielding products. However, the ability to control processes to tighter tolerances is limited by difficulties encountered in obtaining actual in-line (i.e., intra-process) measurements for a given wafer or for a given site on a given wafer.

For example, during rapid thermal anneal (RTA) processes, temperature variations can occur between RTA chambers and within a single chamber from wafer to wafer and at different locations on a single wafer. Such temperature variations can result in variations in dopant activation, dopant diffusion rates, etc., and can thereby result in performance variations from chip to chip and/or from device to device on a single chip. Unfortunately, local on-wafer temperature measurements can not generally be obtained during RTA processing. Thus, current RTA process control techniques involve iterative process and measurement sequences that are used to achieve average process conditions between and within RTA chambers. However, such techniques are costly in terms of time and yield. Therefore, there is a need in the art for an on-wafer (e.g., either on-chip or within the scribe-line) structure that allows for intra-process monitoring and, particularly, intra-anneal monitoring of on-wafer conditions (e.g., temperature) and that, thereby allows for real-time process control.

SUMMARY

In view of the foregoing, disclosed herein are embodiments of a passive resonator that can be formed in a single semiconductor layer of a semiconductor wafer, that can be used for intra-process monitoring and, particularly, intra-anneal monitoring of on-wafer conditions (e.g., temperature) and that, thereby can be used for real-time process control. This passive resonator can comprise three discrete sections of the same semiconductor layer (i.e., a first section, a second section and a third section). The first section can have a defined shape (e.g., a polygon or oval). The second section can have a first end positioned laterally adjacent to and abutting the first section, a middle portion coiled around the first section (i.e., a planar spiral coil inductor portion wrapped multiple times around the first section), and a second end opposite the first end. The third section can be positioned laterally adjacent to and can abut the second end of the second section. The dimensions and shapes of these three discrete sections can be such that the quality (Q) factor of the resonator, which represents the effect of electrical resistance, is at a level sufficient to ensure that the frequency response of the resonator is indicative of the resistance of the resonator, which in turn is indicative of the temperature of the resonator.

Also disclosed are embodiments of a process control system incorporating one or more the above-described passive resonators on a semiconductor wafer. Specifically, the process control system can comprise at least a processing tool, one or more wireless interrogation units and a controller in communication with the processing tool and the interrogation unit(s). The processing tool can process the semiconductor wafer. The interrogation unit(s) can be positioned adjacent to the resonator(s) and, during processing, can apply a stimulus signal to the resonator(s) and can further detect the frequency response of the resonator(s) in response to the stimulus signal. Based on the detected frequency response, the controller can automatically adjust input setting(s) for the processing tool. That is, detected frequency response can be measured and used, by the controller, as the basis for adjusting input setting(s) on the processing tool during processing (i.e., as the basis for making real-time adjustments). For example, during an anneal process performed on a semiconductor wafer by an anneal chamber, detected frequency response can be measured and used, by the controller, as the basis for adjusting temperature setting(s) of the anneal chamber.

Also disclosed are embodiments of a process control method incorporating one or more the above-described passive resonators on a semiconductor wafer. Specifically, the process control method can comprise processing the semiconductor wafer using a processing tool. During processing one or more wireless interrogation unit(s) can be used to apply a stimulus signal to the resonator(s) and further to detect the frequency response of the resonator(s) in response to the applied stimulus signal. Then, based on the frequency response and during processing, the input setting(s) for the processing tool can be automatically adjusted (e.g., by a controller in communication with both the processing tool and the interrogation unit(s)). That is, detected frequency response can be measured and used, by a controller, as the basis for adjusting input setting(s) on the processing tool in real-time. For example, during an anneal process performed on a semiconductor wafer by an anneal chamber, detected frequency response can be measured and used, by the controller, as the basis for adjusting the temperature setting(s) of the anneal chamber.

Also disclosed are embodiments of a non-transitory program storage device readable by a computer and tangibly embodying a program of instructions executable by the computer to perform the above-described process control method.

DETAILED DESCRIPTION

The embodiments of the invention and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description.

As mentioned above, as lithographic geometries are reduced for each successive semiconductor process generation, the effects of process variability have become significant first order issues. Designers are faced with creating tradeoffs between timing margin, power, and performance. Tighter process controls enable lower power, higher performance, and/or higher yielding products. However, the ability to control processes to tighter tolerances is limited by difficulties encountered in obtaining actual in-line (i.e., intra-process) measurements for a given wafer or for a given site on a given wafer.

For example, during rapid thermal anneal (RTA) processes, temperature variations can occur between RTA chambers and within a single chamber from wafer to wafer and at different locations on a single wafer. Such temperature variations can result in variations in dopant activation, dopant diffusion rates, etc., and can thereby result in performance variations from chip to chip and/or from device to device on a single chip. Unfortunately, local on-wafer temperature measurements can not generally be obtained during RTA processing. Thus, current RTA process control techniques involve iterative process and measurement sequences that are used to achieve average process conditions between and within RTA chambers. However, such techniques are costly in terms of time and yield. Therefore, there is a need in the art for an on-wafer (e.g., either on-chip or within the scribe-line) structure that allows for intra-process monitoring and, particularly, intra-anneal monitoring of on-wafer conditions (e.g., temperature) and that, thereby allows for real-time process control.

The following U.S. Patent Applications, which are assigned to International Business Machines, Inc. and incorporated herein by reference, disclose on-wafer structures that allow for wireless process monitoring: U.S. Patent Application Publication No. 2009/0239313 of Anemikos et al. and U.S. Patent Application Publication No. 2009/0240452 of Anemikos et al. The on-wafer structures disclosed in these applications are vertically stacked inductor-capacitor-resistor (LCR) structures that typically include at least one metal layer. While such structures are suitable for some intra-process monitoring, they may not be suitable for use in conjunction with processes, such as rapid thermal anneal (RTA) processes, which occur prior to back end of the line (BEOL) metal layer formation.

In view of the foregoing disclosed herein are embodiments of a passive resonator that can be formed in a single semiconductor layer of a semiconductor wafer, that can be used for intra-process monitoring and, particularly, intra-anneal monitoring of on-wafer conditions (e.g., temperature) and that, thereby can be used for real-time process control. This passive resonator can comprise three discrete sections of the same semiconductor layer (i.e., a first section, a second section and a third section). The first section can have a defined shape (e.g., a polygon or oval). The second section can have a first end positioned laterally adjacent to and abutting the first section, a middle portion coiled around the first section (i.e., a planar spiral coil inductor portion wrapped multiple times around the first section), and a second end opposite the first end. The third section can be positioned laterally adjacent to and can abut the second end of the second section. Optionally, the third section can be at least partially wrapped around the second section. Finally, the sizes and shapes of these discrete sections can be such that the first and third sections exhibit a higher capacitance to the wafer substrate than the second section. Also disclosed herein are embodiments of a process control system and an associated method that incorporate one or more of these passive resonators. In the system and method embodiments, during processing by a processing tool, wireless interrogation unit(s) can detect the frequency response of passive resonator(s) in response to an applied stimulus signal. The detected frequency response can be measured and used as the basis for making real-time adjustments to input settings on the processing tool. For example, a measured frequency response of such a passive resonator can be indicative of the resistance exhibited by that resonator and, thereby indicative of the local temperature at that resonator. Thus, during an anneal process by an anneal chamber, measured frequency response of passive resonator(s) can be used as the basis for making real-time adjustments to the temperature setting(s) of the anneal chamber.

More particularly,FIG. 1is a horizontal cross-section illustration of an embodiment of a passive resonator100that can be formed in a single semiconductor layer104of a semiconductor wafer, that can be used for intra-process monitoring and, particularly, intra-anneal monitoring of on-wafer conditions (e.g., temperature) and that, thereby can be used for real-time process control.FIG. 2is a vertical cross-section illustration of the same passive resonator100(i.e., through the plane A-A′, as shown inFIG. 1).

Referring toFIGS. 1 and 2in combination, this passive resonator100can comprise a patterned portion of a semiconductor layer104above a semiconductor substrate101. In one embodiment, the semiconductor layer104can comprise a polysilicon layer, such as a gate polysilicon layer above a gate dielectric layer103, on a semiconductor-on-insulator (SOI) wafer or bulk semiconductor wafer, as shown. In other embodiments, the semiconductor layer104can comprise any other semiconductor layer above a semiconductor substrate. For example, the semiconductor layer104can comprise a single crystalline silicon layer above an insulator layer of a semiconductor-on-insulator (SOI) wafer. In either case, the passive resonator100can comprise three discrete sections within the patterned portion of the semiconductor layer104(i.e., a first section110, a second section120and a third section130).

The first section110of the passive resonator100can have a defined shape. For example, the first section110can be patterned in the shape of a polygon (e.g., a square, as shown, a rectangle, a hexagon, an octagon, etc.) or oval.

The second section120of the passive resonator100can have a first end121positioned laterally adjacent to and abutting the first section110, a second end122opposite the first end121and a middle portion between the first end121and the second end122. The middle portion of the second section120can be coiled multiple times around the first section110. Specifically, the middle portion of the second section120can comprise a planar spiral coil inductor wrapped multiple times around the first section110. Each coil in this inductor can have a defined shape that conforms to the shape of the first section110. For example, if the first section110is square, then each coil in the inductor can similarly have an essentially square shape, as shown. Alternatively, each coil in the inductor can have a defined shape that is different from the shape of the first section110. For example, if the first section110is square, each coil in the inductor can have a defined shape that is essentially circular or hexagon or any other suitable shape.

The third section130of the passive resonator100can be positioned laterally adjacent to and can abut the second end122of the second section120. The third section130can also have a defined shape that, optionally, wraps at least partially around the second section120(e.g., around at least three sides of the second section120, as shown).

As mentioned above, these discrete sections110,120,130of the resonator100are patterned from a semiconductor layer104. Those skilled in the art will recognize that the semiconductor layer104will have a sheet resistance with a thermal coefficient that causes changes in resistance as a function of changes in temperature. Thus, the dimensions and shapes of these three discrete sections110,120,130of the passive resonator100can be defined such that the quality (Q) factor of the resonator100, which represents the effect of electrical resistance, is at a level (e.g., Q>05) sufficient to ensure that the frequency response of the resonator100is indicative of the resistance of the resonator and, thereby indicative of the local temperature of the resonator100. Specifically, the dimensions and shapes of these discrete sections110,120,130of the passive resonator100can be defined such that the width of each coil in the inductor of the second section as well as the overall length of the inductor of the second section allows for the detection of resistivity changes as a function of temperature. That is, the inductor of the second section120can be configured so that changes in resistance can be detected in response to changes in temperature. The dimensions and shapes of these discrete sections110,120,130of the passive resonator100can further be defined such that the first and third sections110,130of the resonator100each exhibit a significantly higher capacitance to the wafer substrate101than the second section120, thereby raising the quality (Q) factor of the passive resonator100, which represents the effect of resistance, to a level (e.g., Q>0.5) that is sufficient to ensure that the measured frequency response of the passive resonator100(e.g., as measured in terms of Q amplitude vs. frequency) in response to an applied stimulus signal (e.g., a radio frequency energy in the form of a radio frequency pulse or sine voltage applied by a wireless interrogation unit, as discussed in greater detail below) will result in a curve that is indicative of the resistance of the semiconductor material that makes up the passive resonator100and, thereby indicative of the local temperature of the passive resonator100.

Those skilled in the art will recognize that resistivity of the semiconductor layer104can be tailored by doping. Different dopants can be used to achieve different conductivity types in different semiconductor materials. For example, P-type conductivity can be achieved in silicon or polysilicon through the use of a Group III dopant, such as boron (B) or indium (In) and N-type conductivity can be achieved in silicon or polysilicon through the use of a Group V dopant, such as arsenic (As), phosphorous (P) or antimony (Sb). However, P-type conductivity can be achieved in gallium nitride (GaN) through the use of, for example, magnesium (MG) and N-type conductivity can be achieved in gallium nitride (GaN) through the use of, for example, silicon (Si). In any case, the resistivity of the semiconductor layer104can be decreased by increasing the dopant concentration and the particular resistivity characteristics of the semiconductor layer104must be understood so the passive resonator100can be designed with a high enough Q factor to resonate. In the embodiments of the passive resonator100disclosed herein, there is not a specific dopant concentration requirement. However, the higher the resistivity of the semiconductor layer104the better the resonant response. Furthermore, in the embodiments of the passive resonator100disclosed herein, there is also no specific requirement regarding the conductivity type of the dopant (e.g., N-type or P-type) because an AC field will be applied between101and103, as shown inFIG. 2.

Additionally, it should be noted the any spaces between the coils of the inductor of the second section120and also any spaces between each section110,120,130can be filled by dielectric material105. For example, if the passive resonator100comprises a patterned portion of a gate polysilicon layer, as shown, then one or more interlayer dielectric materials (e.g., silicon dioxide, silicon nitride, borophosphosilicate glass (BPSG), etc.) can fill the spaces between the coils of the inductor of the second section120and between each section110,120,130. Whereas, if the passive resonator100comprises a patterned portion of a single crystalline silicon layer of an SOI wafer, then one or more layers of shallow trench isolation (STI) fill materials (e.g., silicon dioxide, silicon nitride, etc.) can fill the spaces between the coils of the inductor of the second section120and between each section110,120,130.

Optionally, one or both of the first and third sections110and130of the passive resonator100, as described above, can be slotted. That is, the first and/or third sections110and130can have one or more slots140(i.e., narrow elongated depressions, grooves, notches, or openings). In one embodiment, the first and/or third sections110,130each slot140can extend vertically completely through the semiconductor layer104. The same dielectric material(s) that fill the spaces between the coils of the inductor of the second section120and between each section110,120,130can fill the slots140. Such slots140can reduce or eliminate (i.e., can be adapted to reduce or eliminate, configured to reduce or eliminate, etc.) heat generating eddy currents (i.e., Foucault currents), which could otherwise impact the accuracy of any temperature measurement calculated based on the frequency response of the passive resonator100in response to an applied stimulus signal.

It should be noted that this passive resonator100can be formed as either a scribe line structure (i.e., within the scribe lines of the semiconductor wafer) or, alternatively, as an on-chip structure (i.e., on a chip being formed on the semiconductor wafer).

Referring toFIG. 3, also disclosed are embodiments of a process control system300incorporating at least one passive resonator100, such as that described in detail above and illustrated inFIGS. 1-2, on a semiconductor wafer301. Specifically, the process control system300can comprise at least a semiconductor wafer301with one or more passive resonators100formed thereon, a processing tool355, at least one wireless interrogation unit340, at least one stimulus source320, at least one sensor330and a controller350in communication the interrogation unit(s)340via the stimulus source(s)320and sensor(s)330and further in communication with the processing tool355.

The processing tool355can process (i.e., can be adapted to process, configured to process, etc.) the semiconductor wafer301. For example, the processing tool355can comprise an anneal chamber that performs (i.e., that is adapted to perform, configured to perform, etc.) an anneal process, such as a rapid thermal anneal (RTA) process, on one or more semiconductor wafers. Such anneal chambers are well-known in the art and, thus, the details are omitted from this specification in order to allow the reader to focus on the salient aspects of the invention.

Each passive resonator100and each interrogation unit340can be uniquely configured so as to allow wireless communication and, particularly, inductive coupling for resonance detection during processing by the process tool350.

For example, an interrogation unit340can comprise an input node341that receives (i.e., that is adapted to receive, configured to receive, etc.) a stimulus signal360(e.g., a given radio frequency energy in the form of a radio frequency pulse or sine voltage) at one end, an output node342at the opposite end and a metal coil that extends from the input node341to the output node342. During processing by the processing tool355, the interrogation unit340can be positioned adjacent to the passive resonator100such that the passive resonator100and interrogation unit340are in close proximity, but physically separated (e.g., by a predetermined distance302). This close proximity allows the interrogation unit340to apply the stimulus signal360to the passive resonator100and further allows the passive resonator100and interrogation unit340to be inductively coupled so that the frequency response370of the passive resonator100, in response to the stimulus signal360, can be detected. To accomplish this, the stimulus source320and the sensor330can each be electrically connected or otherwise in communication with the input and output nodes341-342, respectively, of the interrogation unit340.

A stimulus source320can generate and apply (i.e., can be adapted to generate and apply, configured to generate and apply, etc.) the stimulus signal360to the passive resonator100through the interrogation unit340. For example, the stimulus source320can comprise a pulse generator that generates and applies (i.e., that is adapted to generate and apply, that is configured to generate and apply, etc.) a given radio frequency pulse to the input node341of the interrogation unit340. Alternatively, the stimulus source320can comprise a sine sweep generator that generates and applies (i.e., that is adapted to generate and apply, that is configured to generate and apply, etc.) a given sine voltage to the input node341of the interrogation unit. Additionally, as mentioned above, the interrogation unit340and passive resonator100are placed in close proximity such that, during interrogation, they are inductively coupled. Thus, the behavior of the passive resonator100in response to the applied stimulus signal360will impact the signal at the output node342of the interrogation unit340.

A sensor330(i.e., signal sink) can measure (i.e., can be adapted to measure, configured to measure, etc.) the frequency response370of the passive resonator100in response to the stimulus signal360, as detected by the interrogation unit340. That is, the sensor330can determine the value of the frequency response370in response to the stimulus signal360. For example, if the stimulus source320is a pulse generator, then the sensor330can comprise a spectrum analyzer. This spectrum analyzer can measure (i.e., can be adapted to measure, configured to measure, etc.) the response of the resonator100at the output node342of the interrogation unit340and can further generate (i.e., can be adapted to generate, configured to generate, programmed to generate, etc.) a frequency spectrum (e.g., phase and amplitude vs. frequency). Similarly, if the stimulus source320is a sine sweep generator, the sensor330can comprise a spectrum analyzer that measures the response of the resonator100. In this case, the spectrum analyzer can further generate an amplitude spectrum and a phase spectrum. Such spectrum analyzer output can then be utilized to calculate the Q factor amplitude at a given target frequency, which in turn can be utilized as a measure of temperature.

It should be understood that the stimulus source320and sensor330can comprise discrete transmit and receive units connected to the interrogation unit340, as illustrated. Alternatively, the stimulus source320and sensor330can comprise a combined transmit and receive unit.

The controller350can be in communication with stimulus source320, with the sensor330and with the processing tool355. The controller350can operate (i.e., can be adapted to operate, programmed to operate, etc.) the system300in at least two different modes: (1) a production mode for making essentially real-time process control adjustments; and (2) a characterization/setup mode for generating look-up table(s)351that are used in the production mode.

In the production mode, the controller350can execute (i.e., be adapted to execute) instructions set forth in a process control program352stored in memory. Specifically, as directed by the process control program352, the controller350can initiate operation of the stimulus source320and thereby initiate interrogation of the passive resonator100by the interrogation unit340. Additionally, the controller350can receive the measured frequency response370from the sensor330and can automatically adjust (i.e., can be adapted to automatically adjust, configured to automatically adjust, programmed to automatically adjust, etc.) an input setting for the processing tool355based on that measured frequency response. That is, the detected frequency response of the passive resonator100can be measured by the sensor330and then used by the controller350, as the basis for adjusting the process control signals356sent to the processing tool355during processing (i.e., as the basis for making real-time adjustments).

For example, during an anneal process (e.g., a rapid thermal anneal (RTA) process) performed on a semiconductor wafer301by an anneal chamber355, the stimulus source320can generate and apply a given stimulus signal360to the passive resonator100through the interrogation unit340. The interrogation unit340can detect the frequency response370of the passive resonator100in response to that stimulus signal360and the sensor330can measure the frequency response370of the passive resonator100, as detected by the interrogation unit340. This measured frequency response370can be communicated to the controller350. Next, based on the measured frequency response370, the controller350can calculate the current quality (Q) factor of the passive resonator100, which represents the effect of electrical resistance and can, thereby determine (i.e., be adapted to determine, configured to determine, programmed to determine, etc.) the local temperature of that particular passive resistor100(i.e., the local temperature of the wafer at the passive resonator100) since the passive resonator100is custom designed so that resistance will be indicative of the local temperature.

In the characterization/set up mode, experiments can be performed to determine how the Q factor of a particular passive resonator100incorporated into a particular process control system300will modulate at different frequencies at different temperatures. Specifically,FIG. 4is a graph illustrating results of experimentation indicating modulation of the Q factor, as shown on the y-axis, and the measured frequency, as shown on the x-axis, at different temperatures, as shown in the three discrete curves401,402,403which represent three different temperature simulations for the same passive resonator100. Such results can be used to generate a look-up table(s)351, which correlate the calculated Q value and the measured frequency of a particular passive resonator100at different temperatures and which can be stored in memory.

In the production mode, the look-up table351, which was generated in the characterization/set up mode, can be used to infer the local temperature of the passive resonator100based on the measuring frequency and the calculating the Q factor. For example, referring toFIG. 4, if, in the production mode, the frequency is measured at 5 GHz and the Q factor is calculated at −0.6, then it can be inferred that the local temperature of the passive resonator is that temperature associated with curve402. Further accuracy can be obtained by taking a baseline measurement for each passive resonator100, prior to placing it in the RTA chamber tool. Once the local temperature of the passive resonator100is determined, that local temperature can be used by the controller340as the basis for adjusting (e.g., increasing or decreasing) a temperature setting of the anneal chamber355. Specifically, the controller350can determine (i.e., can be adapted to determine, configured to determine, programmed to determined, etc.) the difference between the local temperature of the passive resonator100and a specified temperature (e.g., the desired anneal temperature) and can automatically adjust (i.e., increase or decrease) a temperature setting on the anneal chamber in order to achieve the specified temperature or to automatically stop the anneal process, when the specified temperature or a temperature vs. time profile is met.

More specifically, in both the characterization/set up mode and the production mode, the process control program352can be loaded into the controller450when a wafer is loaded into the processing tool455. The controller350can repeatedly cause a stimulus signal360to be applied to the input341of the interrogation unit340via the signal source320and can measure the response370at the output342via the signal sink330. The measured response will include the parasitic responses of the on-wafer passive resonator100, which changes in response to the process tool (e.g. temperature of the structure100), the structure of the interrogation unit340itself and the other elements and wiring as shown inFIG. 3.

As mentioned above, the stimulus signal360can take any one of various different forms. For example, the stimulus signal360can comprise a SINC (sin(x)/x) signal or a short duration impulse signal). The resulting frequency response370can comprise a current waveform (e.g., current vs. time) measured by the signal sink360. This frequency response370can then be processed by the controller350(e.g., the controller450can perform a Fourier transform of this time domain signal). The Fourier transform results provide both an amplitude and phase vs. frequency response of the system, which includes the device under test (DUT) (i.e., the passive resonator100). Alternatively, the stimulus signal360can comprise a sine signal applied at the target frequency (or frequencies). In this case, the resulting frequency response can comprise a current and voltage response, which can be measured by the signal sink430(vs. time) and can be further processed by the controller350to create amplitude and phase vs. frequency relationships.

Also as mentioned above, the resulting frequency response370can be used by the controller350to calculate the Q factor of the passive resonator100. Conventional techniques can be used by the controller350to calculate the Q factor and these techniques may vary depending upon the type of measured response370. For example, if the controller350processes the frequency response into a Fourier transform, the controller350can further measure the width of a Fourier transform amplitude vs. frequency response around the frequency of interest, with the center measurement point being the peak value, and the left and right sides being that frequency at which a square root of two amplitude of the peak values is measured. The Q factor then becomes the measurement which is correlated to the process parameter of interest (e.g., the local temperature of the passive resonator100). Other techniques for calculating the Q factor of a resonator based on a frequency response are well-known in the art and, thus, the details are omitted from this specification in order to allow the reader to focus on the salient aspects of the invention.

In the characterization/set up mode, the particular passive resonator100as incorporated into the system300is characterized in order to establish the mathematical relationship between the frequency response of the particular passive resonator100and the target process tool conditions. Specifically, during this characterization mode, the particular passive resonator100is interrogated at different process tool conditions in order to experimentally determine the mathematical relationship between the frequency response of the particular passive resonator100and the target process tool conditions. The mathematical relationship can then be used to establish lookup table(s)351, which can be used by the controller350in the production mode to make essentially real-time process control adjustments.

For example, if the processing tool355is a RTA chamber, a particular passive resonator100can first be interrogated with the RTA chamber set at room temperature or some other stable temperature. The wafer can be left in the RTA chamber long enough for the passive resonator100to reach the RTA chamber temperature. Next, the passive resonator100can be interrogated via the interrogation unit340(i.e., a stimulus signal360can be applied by the signal source320to the input of the interrogation unit340and the resulting response370at the output of the interrogation unit340can be measured by the signal sink330). The measured response can then be analyzed by the controller350(i.e., the controller350can calculate the Q factor of the passive resonator100). These processes can be repeated (e.g., manually or programmatically) for various different higher RTA chamber temperatures, again making sure that the wafer has been left in the RTA chamber long enough for the passive resonator to reach the RTA chamber temperature (e.g., as measured by a native chamber temperature sensor). Based on the results of these processes, the particular passive resonator100as incorporated into the system300can be characterized in order to establish the mathematical relationship between the frequency response of the particular passive resonator100and the target local temperature conditions. From the mathematical relationships, look-up table(s)351that correlate the measured response and process parameter (in this case, the Q factor and resistance as well as resistance and temperature) can be generated and stored and the process control program352can be updated, as necessary.

In production mode, the particular passive resonator100as incorporated into the system300is monitored and used to control the process parameter of interest. Specifically, during this production mode, the particular passive resonator100is interrogated by the interrogation unit340(as discussed in detail above) during processing. The controller350then calculates the Q factor based on the measured frequency response370and accesses the previously generated look-up table(s)351to determine if the results coincide with the target process conditions. If not, input settings on the process control tool can be adjusted accordingly. Such monitoring can also be performed in order to determine if the processing end point has been achieved. Thus, the system300incorporating the passive resonator100allows for real-time monitoring and control of a target process parameter.

For example, if the processing tool355is a RTA chamber, a particular passive resonator100can be interrogated by the interrogation unit340(as discussed in detail above) during processing. The controller350then calculates the Q factor of the resulting frequency response370and accesses the previously generated look-up table(s)351to determine if the results coincide with the target local temperature for the passive resonator100. The system300can then compensate for any temperature variations within the chamber or can determine that the process end point (e.g., a specific temperature or temperature vs. time profile) has been achieved. Thus, the system300incorporating the passive resonator100allows for real-time monitoring and control of the local target process temperature.

Referring toFIGS. 5 and 6, the above described process control system300can optionally incorporate multiple passive resonators100a-cacross the semiconductor wafer301so as to allow multiple local intra-process temperatures to be determined and, thereby to allow multiple local temperature settings on the anneal chamber to be automatically adjusted.

Specifically, referring toFIG. 5in combination withFIG. 3, one embodiment of the process control system300can further comprise multiple passive resonators100a-con a semiconductor wafer301and multiple interrogation units340a-cfor interrogating corresponding passive resonators100a-c. The passive resonators100a-ccan be at different locations across the semiconductor wafer301, either in the same semiconductor layer or in different semiconductor layers. Each interrogation unit340a-ccan be positioned adjacent to a corresponding one of the passive resonators100a-c. During processing by the processing tool355, each interrogation unit340a-ccan apply a stimulus signal to its corresponding passive resonator100a-cand can further detect the frequency response of its corresponding passive resonator100a-cin response to that stimulus signal. As in the previously described embodiment, a stimulus source can generate and apply a given stimulus signal to the passive resonator through each interrogation unit and a sensor can measure the frequency response of each passive resonator in response to the stimulus signal. It should be noted that in this embodiment discrete stimulus sources and sensors can be connected to each interrogation unit. Alternatively, a single stimulus source and a single sensor can be selectively connected (e.g., via a multiplexor) to each interrogation unit340a-c. Once the frequency responses of each of the passive resonators100a-care measured, the controller350can calculate corresponding Q factors of the passive resonators100a-cbased on the measured frequency responses, can determine the local temperatures of the passive resonators100a-cusing previously generated and stored look-up tables351and based on the corresponding calculated Q factors and measured frequencies, and can automatically adjust local temperature settings within the anneal chamber355based on the local temperatures.

Alternatively, referring toFIG. 6in combination withFIG. 3, another embodiment of the process control system300can further comprise multiple passive resonators100a-con a semiconductor wafer and a single interrogation unit340. The passive resonators100a-ccan be at different locations across the semiconductor wafer, either in the same semiconductor layer or in different semiconductor layer. The interrogation unit340can be positioned adjacent to each of the passive resonators100a-c. During processing by the processing tool355, the interrogation unit340can apply a stimulus signal to all of the passive resonators100a-cand can further detect the combined frequency responses of the passive resonators100a-cin response to the stimulus signal. To accomplish this, a stimulus source can generate and apply a given stimulus signal to the passive resonators100a-cthrough the interrogation unit and a sensor can measure the combined frequency responses of the passive resonators100a-cin response to the applied stimulus signal. Given the value of the combined frequency responses, the controller350can determine the individual frequency responses of each passive resonator100a-c.

Specifically, when a single440interrogation unit is used to interrogate multiple passive resonators100, as shown inFIG. 6, the multiple sites concurrently being excited and measured must be designed for separated frequency response peaks in the Q curves. For example, referring toFIG. 7, a first passive resonator would be designed to have one set of response curves. Such curves like the curves shown inFIG. 4and described in detail above, illustrate results of experimentation indicating modulation of the Q factor, as shown on the y-axis, and the measured frequency, as shown on the x-axis, at different temperatures, as shown in the three discrete curves711,712,713which represent three different temperature simulations for the same first passive resonator. In this case, the response curves have relative quiet zones at 3.5-4.5 GHz (see Zone1) and 9 GHz and above, and an active zone of interest from 5.5 to 6.5 GHz (see Zone2). Additionally, a second passive resonator would be designed to have another set of response curves. Such curves would similarly illustrate results of experimentation indicating modulation of the Q factor, as shown on the y-axis, and the measured frequency, as shown on the x-axis, at different temperatures, as shown in the three discrete curves721,722,723which represent three different temperature simulations for the same second passive resonator. The second passive resonator can specifically be design so that its response curves are active between approximately 3.5 GHz and 4.5 GHz (see Zone1) and quiet above 4.5 GHz (see Zone2) and, thus, only minimally impact measurements of the first passive resonator. Procedurally, the multiple passive resonators to be monitored would first be interrogated, prior to wafer processing at room temperature outside the RTA chamber, in order to establish a baseline measurement for those passive resonators at a known temperature. Then, process control tool measurements can be scaled to account for any structure to structure response variations between die sites across wafers.

Once the frequency responses of each of the passive resonators100a-care determined, the controller350can calculate the corresponding Q factors of the passive resonators100a-cbased on the individual frequency responses, can determine the local temperatures of the passive resonators100a-cusing previously generated and stored look-up tables351and based on the corresponding calculated Q factors and measured frequencies, and can automatically adjust local temperature settings within the anneal chamber355based on the local temperatures.

Referring toFIG. 8, also disclosed herein are embodiments of a method of forming a passive resonator100such as that described above and illustrated inFIGS. 1-2. The method of forming the passive resonator100can comprise providing a semiconductor wafer (e.g., a semiconductor-on-insulator (SOI) wafer, bulk semiconductor wafer or any other suitable semiconductor wafer) (802). The passive resonator100can be patterned (e.g., using conventional lithographic patterning techniques) and etched into a single semiconductor layer104on that semiconductor wafer (804). For example, in one embodiment, a gate dielectric layer103can be formed on the top surface of the semiconductor wafer. Next, a gate polysilicon layer104can be formed on the gate dielectric layer. The passive resonator100can then be patterned and etched into a portion of the gate polysilicon layer during the formation of polysilicon gate structures for other devices on the semiconductor wafer. Alternatively, the passive resonator100can be patterned and etched into any other semiconductor layer on the semiconductor wafer. For example, the passive resonator100can be patterned and etched into a single crystalline silicon layer above an insulator layer of a semiconductor-on-insulator (SOI) wafer. In either case, the passive resonator100can be patterned and etched at process804such that it comprises three discrete sections of this semiconductor layer104(i.e., a first section110, a second section120and a third section130).

The first section110of the passive resonator100can be patterned and etch such that it has a defined shape. For example, the first section110can be patterned and etched in the shape of a polygon (e.g., a square, as shown, a rectangle, a hexagon, an octagon, etc.) or oval.

The second section120of the passive resonator100can essentially simultaneously be patterned and etched such that it has a first end121positioned laterally adjacent to and abutting the first section110, a second end122opposite the first end121and a middle portion between the first end121and the second end122. The second section120can further be patterned and etched such that the middle portion is coiled multiple times around the first section110. Specifically, the second section120can be patterned and etched such that the middle portion comprises a planar spiral coil inductor wrapped multiple times around the first section110. Each coil in this inductor can have a defined shape that conforms to the shape of the first section110. For example, if the first section110is square, then each coil of the inductor can similarly have an essentially square shape, as shown. Alternatively, each coil in this inductor can have a defined shape that is different from the shape of the first section110. For example, if the first section110is square, then each coil in the inductor can have an essentially circular or hexagon or any other suitable shape.

The third section130of the passive resonator100can essentially simultaneously be patterned and etched such that it is positioned laterally adjacent to and abutting the second end122of the second section120. The third section130can also be patterned and etched so as to have a defined shape that, optionally, wraps at least partially around the second section120(e.g., around at least three sides of the second section120, as shown.

Prior to patterning and etching the semiconductor layer104at process804to form the passive resonator100, the dimensions and shapes of these discrete sections110,120,130as well as any doping must be defined. As mentioned above, these discrete sections110,120,130of the resonator100are patterned from a semiconductor layer104. Those skilled in the art will recognize that the semiconductor layer104will have a sheet resistance with a thermal coefficient that causes changes in resistance as a function of changes in temperature. Thus, the dimensions and shapes of these three discrete sections110,120,130of the passive resonator100can be defined such that the quality (Q) factor of the resonator100, which represents the effect of electrical resistance, is at a level (e.g., Q>05) sufficient to ensure that the frequency response of the resonator100is indicative of the resistance of the resonator and, thereby indicative of the local temperature of the resonator100. Specifically, the dimensions and shapes of the discrete sections110,120and130of the passive resonator100should be defined such that width of the coils in the inductor of the second section120as well as the overall length of that inductor allow for the detection of resistivity changes as a function of temperature (805). That is, the dimensions and shape of the inductor of the second section120can be defined so as to allow changes in resistance to be detected in response to changes in temperature. Additionally, the dimensions and shapes of these discrete sections110,120,130of the passive resonator100should be defined such that the first and third sections110,130of the resonator100each exhibit a significantly higher capacitance to the wafer substrate101than the second section120, thereby raising the quality (Q) factor of the passive resonator100to a level (e.g., Q>0.5) that is sufficient to ensure that the measured frequency response of the passive resonator100(e.g., as measured in terms of Q amplitude vs. frequency) in response to an applied stimulus signal (e.g., a given radio frequency energy in the form of a radio frequency pulse or sine voltage applied by a wireless interrogation unit, as discussed in greater detail below) will be indicative of the resistance of the semiconductor material that makes up the passive resonator100and, thereby indicative of the local temperature of the passive resonator100(806).

Those skilled in the art will recognize that resistivity of the semiconductor layer104can be tailored by doping. Different dopants can be used to achieve different conductivity types in different semiconductor materials. For example, P-type conductivity can be achieved in silicon or polysilicon through the use of a Group III dopant, such as boron (B) or indium (In) and N-type conductivity can be achieved in silicon or polysilicon through the use of a Group V dopant, such as arsenic (As), phosphorous (P) or antimony (Sb). However, P-type conductivity can be achieved in gallium nitride (GaN) through the use of, for example, magnesium (MG) and N-type conductivity can be achieved in gallium nitride (GaN) through the use of, for example, silicon (Si). In any case, the resistivity of the semiconductor layer104can be decreased by increasing the dopant concentration and the particular resistivity characteristics of the semiconductor layer104must be understood so the passive resonator100can be designed with a high enough Q factor to resonate. In the embodiments of the passive resonator100disclosed herein, there is not a specific dopant concentration requirement. However, the higher the resistivity of the semiconductor layer104the better the resonant response. Furthermore, in the embodiments of the passive resonator100disclosed herein, there is also no specific requirement regarding the conductivity type of the dopant (e.g., N-type or P-type) because an AC field will be applied between101and103, as shown inFIG. 2.

Once the discrete sections110,120,130are patterned and etched at process804, one or more dielectric materials105can be deposited so as to fill any spaces between the coils of the inductor of the second section120and between each section110,120,130(808). For example, if the passive resonator100is patterned into a portion of a gate polysilicon layer, as shown, then one or more interlayer dielectric materials (e.g., silicon dioxide, silicon nitride, borophosphosilicate glass (BPSG), etc.) can be deposited into the spaces between the coils of the inductor of the second section120and between each section110,120,130. Whereas, if the passive resonator100is patterned into a portion of a single crystalline silicon layer of an SOI wafer, then one or more layers of shallow trench isolation (STI) fill material (e.g., silicon dioxide, silicon nitride, etc.) can be deposited into the spaces between the coils of the inductor of the second section120and between each section110,120,130.

Optionally, one or both of the first and third sections110and130of the passive resonator100, as described above, can further be patterned and etched with slots140(807). That is, the first and/or third sections110and130can be patterned and etched so as to have one or more slots140(i.e., narrow elongated depressions, grooves, notches, or openings). In one embodiment, the first and/or third sections110,130can specifically be patterned and etched with multiple slots140such that each slot extends vertically completely through the semiconductor layer104. The same dielectric material(s)105that are deposited at process808to fill the spaces between the coils of the inductor of the second section120and between each section110,120,130can also fill the slots140. Such slots140can reduce or eliminate (i.e., can be adapted to reduce or eliminate, configured to reduce or eliminate, etc.) heat generating eddy currents (i.e., Foucault currents), which could otherwise impact the accuracy of any temperature measurement calculated based on the frequency response of the passive resonator100in response to an applied stimulus signal.

It should be noted that the passive resonator100can be formed at process804as either a scribe line structure (i.e., within the scribe lines of the semiconductor wafer) or, alternatively, as an on-chip structure (i.e., on a chip being formed on the semiconductor wafer).

Referring toFIG. 9in combination withFIG. 3, also disclosed are embodiments of a process control method incorporating at least one passive resonator100on a semiconductor wafer301. This process control method can comprise first characterizing a particular passive resonator100(901). Specifically, experiments can be performed to determine how the Q factor of a particular passive resonator100incorporated into a particular process control system300will modulate at different frequencies at different temperatures. For example,FIG. 4is a graph illustrating results of experimentation indicating modulation of the Q factor, as shown on the y-axis, and the measured frequency, as shown on the x-axis, at different temperatures, as shown in the three discrete curves401,402,403which represent three different temperature simulations for the same passive resonator100. Such results can be used to generate a look-up table(s)351, which correlate the calculated Q value and the measured frequency of a particular passive resonator100at different temperatures and which can be stored in memory.

Next, a semiconductor wafer301that incorporates such a passive resonator100can be processed using a processing tool355(902). For example, the processing tool355can comprise an anneal chamber that performs an anneal process, such as a rapid thermal anneal (RTA) process, on one or more semiconductor wafers. Such rapid thermal anneal processes are well-known in the art and, thus, the details are omitted from this specification in order to allow the reader to focus on the salient aspects of the invention.

This process control method can further comprise using a wireless interrogation unit340to wirelessly interrogate a passive resonator100on the semiconductor wafer during processing (904). Specifically, the passive resonator100and the interrogation unit340can be uniquely configured so as to allow wireless communication and, particularly, inductive coupling for resonance detection during processing by the process tool350. For example, the interrogation unit340can comprise an input node341that receives (i.e., that is adapted to receive, configured to receive, etc.) a stimulus signal360(e.g., a given radio frequency energy in the form of a radio frequency pulse or sine voltage) at one end, an output node342at the opposite end and a metal coil that extends from the input node341to the output node342. During processing by the processing tool355, the interrogation unit340can be positioned adjacent to the passive resonator100such that the passive resonator100and interrogation unit340are in close proximity, but physically separated (e.g., by a predetermined distance302). This close proximity allows the interrogation unit340to apply the stimulus signal360to the passive resonator100and further allows the passive resonator100and interrogation unit340to be inductively coupled so that the frequency response370of the passive resonator100, in response to the stimulus signal360, can be detected. To accomplish this, a stimulus source320and a sensor330can each be electrically connected or otherwise in communication with the input and output nodes341-342, respectively, of the interrogation unit340.

For example, during this interrogation process904, a stimulus signal360(e.g., a radio frequency pulse or sine voltage) can be generated and applied (e.g., by a stimulus source320, such as a pulse generator or sine sweep generator, respectively) to the passive resonator100through the interrogation unit340(905). The close proximity of the interrogation unit340and passive resonator100allows for inductive coupling such that the behavior of the passive resonator100in response to the applied stimulus signal360will impact the signal at the output node342of the interrogation unit340. Thus, the interrogation process904can further comprise detecting (e.g., by the interrogation unit340) the frequency response370of the passive resonator100in response to the applied stimulus signal360and measuring (e.g., by a sensor330) that frequency response370(i.e., determining the value of that frequency response370) (905). It should be noted that, if the stimulus source320is a pulse generator, then the sensor330can comprise a spectrum analyzer. This spectrum analyzer can measure the response of the resonator100at the output node342of the interrogation unit340and can further generate a frequency spectrum (e.g., phase and amplitude vs. frequency). Similarly, if the stimulus source320is a sine sweep generator, the sensor330can comprise a spectrum analyzer that measures the response of the resonator100. In this case, the spectrum analyzer can further generate an amplitude spectrum and a phase spectrum.

The measured frequency response370can then be used (e.g., by a controller350and as processing is still being performed) as the basis for automatically adjusting an input setting for the processing tool355(910). That is, the detected and measured frequency response370of the passive resonator100can then used as the basis for making real-time process adjustments.

For example, during an anneal process (e.g., a rapid thermal anneal (RTA) process) performed on a semiconductor wafer301by an anneal chamber355at process905, a given stimulus signal360can be generated and applied to the passive resonator100through the interrogation unit340. The frequency response370of the passive resonator100in response to that stimulus signal360can be detected and measured. Based on the measured frequency response, the Q factor of the passive resonator100, which represents the effect of resistance, can be calculated (e.g., by a controller350) (911). Then, using the look-up table351generated and stored at process901, the temperature of that particular passive resistor100(i.e., the local temperature of the wafer at the passive resonator100) can be determined (e.g., by the controller350) based on the calculated Q factor and the measured frequency (911, see detailed discussion above with regard to the system embodiment). Finally, once the local temperature of the passive resonator100is determined, that local temperature can be used (e.g., also by the controller340) as the basis for adjusting (e.g., increasing or decreasing) a temperature setting of the anneal chamber355(911). Specifically, the difference between the determined temperature of the passive resonator100and a specified temperature (e.g., the desired anneal temperature) can determined (e.g., by the controller350) and the temperature setting on the anneal chamber can be automatically adjusted (e.g., increased or decreased) in order to achieve the specified temperature or to automatically stop the anneal process, when the specified temperature or a temperature vs. time profile is met.

The above-described process control method can optionally incorporate multiple passive resonators100a-cacross the semiconductor wafer301, as shown inFIGS. 5 and 6, so as to allow multiple local intra-process temperatures to be determined and, thereby to allow multiple local temperature settings on the anneal chamber to be automatically adjusted.

Specifically, one embodiment of the process control method can further incorporate the use of multiple passive resonators100a-con a single semiconductor wafer301and multiple interrogation units340a-cfor interrogating corresponding passive resonators100a-c(as shown inFIG. 5). The passive resonators100a-ccan be at different locations across the semiconductor wafer301, either in the same semiconductor layer or in different semiconductor layers. Each interrogation unit340a-ccan be positioned adjacent to a corresponding one of the passive resonators100a-c. During interrogation at process904, each interrogation unit340a-ccan apply a stimulus signal to its corresponding passive resonator100a-cand can further detect the frequency response of its corresponding passive resonator100a-cin response to that stimulus signal (906). As in the previously described embodiment, a stimulus source can generate and apply a given stimulus signal to the passive resonator through each interrogation unit and a sensor can measure the frequency response of each passive resonator in response to the stimulus signal. It should be noted that in this embodiment discrete stimulus sources and sensors can be connected to each interrogation unit. Alternatively, a single stimulus source and a single sensor can be selectively connected (e.g., via a multiplexor) to each interrogation unit340a-c. Once the frequency responses of each of the passive resonators100a-care measured, the corresponding Q factors of the passive resonators100a-ccan be calculated based on the measured frequency responses, the local temperatures of the passive resonators100a-ccan be determined using previously generated and stored look-up tables351and based on the corresponding calculated Q factors and measured frequencies, and local temperature settings within the anneal chamber355can be automatically adjust based on the local temperatures (911).

Alternatively, another embodiment of the process control method can incorporate the use of multiple passive resonators100a-con a semiconductor wafer and a single interrogation unit340(as shown inFIG. 6). The passive resonators100a-ccan be at different locations across the semiconductor wafer, either in the same semiconductor layer or in different semiconductor layer. The interrogation unit340can be positioned adjacent to each of the passive resonators100a-c. During interrogation at process904, the interrogation unit340can apply a stimulus signal to all of the passive resonators100a-cand can further detect the combined frequency responses of the passive resonators100a-cin response to the stimulus signal (907). To accomplish this, a stimulus source can generate and apply a given stimulus signal to the passive resonators100a-cthrough the interrogation unit and a sensor can measure the combined frequency responses of the passive resonators100a-cin response to the applied stimulus signal. Given the value of the combined frequency responses, the individual frequency responses of each passive resonator100a-ccan then be determined (e.g., by the controller350) (see detailed discussion above with regard to the system embodiment). Once the frequency responses of each of the passive resonators100a-care determined, the corresponding Q factors of the passive resonators100a-ccan be calculated based on the measured frequency responses, the local temperatures of the passive resonators100a-ccan be determined using previously generated and stored look-up tables351and based on the corresponding calculated Q factors and measured frequencies, and local temperature settings within the anneal chamber355can be automatically adjust based on the local temperatures (911).

It should further be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should further be understood that the terms “comprises” “comprising”, “includes” and/or “including”, as used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Additionally, it should be understood that the corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Therefore, disclosed above are embodiments of a passive resonator that can be formed in a single semiconductor layer of a semiconductor wafer, that can be used for intra-process monitoring and, particularly, intra-anneal monitoring of on-wafer conditions (e.g., temperature) and that, thereby can be used for real-time process control. This passive resonator can comprise three discrete sections of the same semiconductor layer (i.e., a first section, a second section and a third section). The first section can have a defined shape (e.g., a polygon or oval). The second section can have a first end positioned laterally adjacent to and abutting the first section, a middle portion coiled around the first section (i.e., a planar spiral coil inductor portion wrapped multiple times around the first section), and a second end opposite the first end. The third section can be positioned laterally adjacent to and can abut the second end of the second section. Optionally, the third section can be at least partially wrapped around the second section. Finally, the sizes and shapes of these discrete sections can be such that the first and third sections exhibit a higher capacitance to the wafer substrate than the second section.

Also disclosed above are embodiments of a process control system and an associated method that incorporate one or more of these passive resonators. In the system and method embodiments, during processing by a processing tool, wireless interrogation unit(s) can detect the frequency response of passive resonator(s) in response to an applied stimulus signal. The detected frequency response can be measured and used as the basis for making real-time adjustments to input settings on the processing tool. For example, a measured frequency response of such a passive resonator can be indicative of the resistance exhibited by that resonator and, thereby indicative of the local temperature at that resonator. Thus, during an anneal process by an anneal chamber, measured frequency response of passive resonator(s) can be used as the basis for making real-time adjustments to the temperature setting(s) of the anneal chamber.

As mentioned above, a passive resonator, such as that described above and illustrated inFIGS. 1-2, can be formed as a scribe line structure (i.e., within the scribe lines of the semiconductor wafer) or, alternatively, as an on-chip structure (i.e., on a chip being formed on the semiconductor wafer). Those skilled in the art will recognize that in addition to being used for intra-processing monitoring and control, as discussed in detail above, an on-chip passive resonator may similarly be wirelessly interrogated for post-production purposes. For example, an on-chip passive resonator could also be wirelessly interrogated for temperature sensing during testing and/or in the field.