Automatic probe landing

Abstract

To provide an automated method for landing a probe on a device under test (DUT).SOLUTION: An automated probe landing system 100 lands a probe on a device under test (DUT) by: positioning a conductive probe 114 above the DUT by a motion control device; applying electrical signals to between the conductive probe and the DUT; measuring electrical responses from the applied electrical signals; calculating impedance magnitude values and / or phase angle values based on the measured electrical response values; causing the conductive probe to move towards the DUT while continuing to calculate impedance magnitude values and / or phase angle values from measured electrical responses; determining that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude values and / or phase angle values; and signaling to the motion control device to stop moving the probe towards the DUT.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED PATENT APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 267,983, filed February 14, 2022, which claims the benefit of U.S. Application No. 17 / 943,847, filed September 13, 2022. [Background technology]

[0002] Charged particle beam (CPB) imaging systems can be used to study nanometer-scale objects. Typically, CPB imaging systems use a charged particle beam, such as an electron beam, that illuminates an object to visualize the object or features of the object that cannot be visualized using an optical microscope. For example, features smaller than the wavelength of light can be visualized using a CPB imaging system.

[0003] CPB imaging systems can display atomic detail with sub-nanometer resolution (e.g., down to about 0.1 nm resolution) at magnifications up to about 1 million times. CPB imaging systems include scanning electron microscopes (SEMs), focused ion beam (FIB) microscopes, and transmission electron microscopes (TEMs), among others.

[0004] A scanning electron microscope (SEM) is a type of CPB imaging system. In an SEM, an electron beam is scanned over the surface of an object. A detector collects reflected, absorbed, or backscattered, absorbed, and / or secondary electrons from the object's surface and converts the collected electrons into a signal that is used to generate a real-time, multi-dimensional visualization of the sample. Summary of the Invention [Problem to be solved by the invention]

[0005] Semiconductor processing has achieved single digit nanometer feature sizes (e.g., 5 nm feature sizes). In-situ manual probing into CPB systems has been demonstrated as a reliable technique for testing semiconductor devices containing single digit nanometer feature sizes, but is labor intensive and has low throughput. Automating the probing process increases the number of devices that can be tested and frees tool users to work more effectively in other areas of work. A key component of an automated probe is an automated landing surface. This disclosure focuses on solving the problem of how to automate a probe landing surface. [Means for solving the problem]

[0006] Aspects of an embodiment include an automated method for landing a probe on a device under test (DUT), the method including the steps of: positioning a conductive probe over the DUT by an automated motion control system; applying an electrical signal between the conductive probe and the DUT by a signal measurement circuit; measuring an electrical response from the applied electrical signal by the signal measurement circuit; calculating by a processor an impedance magnitude value and / or a phase angle value based on the measured electrical response value; moving the conductive probe toward the DUT while continuing to calculate, by the automated motion control system, an impedance magnitude value and / or a phase angle value from the measured electrical response; determining by the processor that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or phase angle value; and sending a signal by the processor to the automated motion control system to stop movement of the probe toward the DUT based on a change in the calculated impedance magnitude value and / or phase angle value. The motion control device can automatically stop the probe based on receiving a signal from the processor indicating that the probe has contacted a surface, where such indication of surface contact is based on the impedance and / or phase determination.

[0007] In some embodiments, determining that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or phase angle value includes determining by the processor a change in a rate of change of the calculated impedance magnitude value and / or phase angle value.

[0008] In some embodiments, the change in the calculated impedance magnitude value and / or phase angle value includes a value, or an average of the values, a change by a predetermined amount from a baseline, or a match / crossing with an absolute value.

[0009] In some embodiments, the change in the calculated impedance magnitude value and / or phase angle value includes a change in a noise measure, frequency, or profile from a baseline or from matching / intersecting with an absolute measure, frequency, or profile.

[0010] In some embodiments, the change in the calculated impedance magnitude value and / or phase angle value comprises a rate of change that changes from a baseline by a predetermined amount, or that meets / crosses an absolute rate of change.

[0011] Some embodiments may also include performing electrical tests on the DUT.

[0012] Some embodiments may also include determining that electrical testing of the DUT is complete, sending a signal to an operational control device to disconnect the conductive probe from the DUT, and determining, by the processor, that the conductive probe has disconnected from the DUT based on the aforementioned change in the calculated impedance magnitude value and / or phase angle value.

[0013] Some embodiments may also include determining a second DUT to test based on the test plan, and sending a signal to the operation control device to position the conductive probe over the second DUT.

[0014] In some embodiments, the step of placing the conductive probe over the second DUT further includes the steps of identifying coordinates of the second DUT and placing the conductive probe over the second DUT based on the coordinates of the second DUT.

[0015] In some embodiments, the step of positioning the conductive probe over the second DUT includes the steps of determining coordinates of the second DUT and positioning the second DUT under the conductive probe based on a transformation of the coordinates of the second DUT.

[0016] Some embodiments may also include determining a type of DUT from the received impedance magnitude values ​​and / or phase angle values ​​based at least in part on comparing the calculated impedance magnitude and phase angle with historical values.

[0017] Some embodiments may also include stopping testing of the DUT before testing of the DUT is completed, measuring impedance magnitude values ​​and / or phase angle values, determining that the conductive probe has drifted or moved from the DUT, repositioning the conductive probe on the DUT, and completing testing of the DUT.

[0018] Some embodiments may also include determining, by the processor, that the impedance magnitude value and / or phase angle value indicate proximity between the conductive probe and the DUT, and signaling a motion control device to increase or decrease a speed of movement of the conductive probe toward the DUT based on the proximity between the conductive probe and the DUT determined from the impedance magnitude value and / or phase angle value.

[0019] Some embodiments may also include determining, by the processor, that the impedance magnitude value and / or the phase angle value are indicative of a physical shape of the conductive probe, determining whether the physical shape of the conductive probe is suitable for contacting the DUT based on the impedance magnitude value and / or the phase angle value, and signaling a motion control device to stop and abort processing if the conductive probe does not have a physical shape for contacting the DUT, or signaling a motion control device to continue moving the probe toward the DUT if the conductive probe has a physical shape for contacting the DUT.

[0020] Aspects of an embodiment include a system comprising: a nanoprober including an actuator for fixing a conductive probe; a signal measurement circuit electrically coupled to the conductive probe, the signal measurement circuit applying a signal to the conductive probe and receiving a signal from the sample or applying a signal to the sample and receiving a signal from the conductive probe; a motion control system moving the nanoprober actuator based on information received from the signal measurement circuit; and a hardware processor determining that the information from the signal measurement circuit is indicative of proximity of the conductive probe to a target surface, determining that the information from the signal measurement circuit is indicative of suitability or quality of the conductive probe, determining that the information from the signal measurement circuit is indicative of the conductive probe having been brought to rest on the target surface, and signaling the motion control system to stop movement of the nanoprober positioning device based on the indication that the conductive probe has been brought to rest on the target surface.

[0021] In some embodiments, the motion control system lowers the conductive probe towards the DUT while the signal measurement circuit receives the electrical information and the processor calculates the magnitude of the impedance and the phase angle between the voltage and current based on the received electrical information.

[0022] In some embodiments, the processor determines that the magnitude of the received impedance or the phase angle between the voltage and current values ​​is indicative of the proximity of the tip of the conductive probe to the DUT and sends a signal to a motion control system to modify the speed of movement of the conductive probe towards the DUT based on the proximity.

[0023] In some embodiments, the processor determines that the magnitude of the received impedance or the phase angle between the voltage and current values ​​is indicative of landing an unusable probe tip on the DUT and signals the motion control system to stop moving the conductive probe towards the DUT and abort the landing.

[0024] In some embodiments, the processor determines whether the magnitude of the received impedance or the phase angle between the voltage and current values ​​meets or exceeds a threshold value, or any other change in behavior from a calculated criteria, determines that the conductive probe has contacted the DUT based on whether the magnitude of the impedance or the phase angle between the voltage and current values ​​meets or exceeds a threshold value, or any other change in behavior from a calculated criteria, and signals the motion control system to stop moving the conductive probe towards the DUT.

[0025] In some embodiments, the processor determines what the DUT is based on the stored information and performs electrical testing of the DUT via the signal measurement circuitry based on what the DUT is.

[0026] In some embodiments, the processor can determine that electrical testing of the DUT is complete and signal the motion control device to lift the conductive probe off the DUT or move the DUT away from the conductive probe.

[0027] In some embodiments, the processor can determine a second DUT to test based on the test plan, identify a position of the second DUT, and move one or both of a sample stage supporting the second DUT and the tip of the conductive probe so that the tip of the conductive probe is above the second DUT.

[0028] In some embodiments, the processor can determine coordinates of a second DUT and, based on the coordinates of the second DUT, signal the motion control system to position a conductive probe over the second DUT or signal the motion control system to position the DUT under an origin of a charged particle beam (CPB) device.

[0029] In some embodiments, the processor can determine coordinates of the second DUT and signal the motion control system to position the conductive probe over the second DUT based on a transformation of the coordinates of the second DUT.

[0030] In some embodiments, the processor may determine the type of DUT based on a comparison of the electrical information calculated from the received impedance magnitude values ​​and / or phase angle between the voltage and current values ​​to historical values.

[0031] In some embodiments, the processor can stop the electrical testing of the DUT before the electrical testing of the DUT is completed, determine via the current received via the signal measurement circuitry a value of the impedance magnitude and / or a phase angle between the voltage and current, determine that the conductive probe has drifted or moved away from the DUT, and signal the motion control system to reposition the conductive probe over the DUT to complete the electrical testing of the DUT.

[0032] Aspects of an embodiment include a system, the system including: a nanoprober system that secures a conductive probe; a motion control system; a signal measurement circuit that applies a signal to the conductive probe and receives a signal from the sample or applies a signal to the sample and receives a signal from the probe; the motion control system that moves a nanoprober positioning device based on information received from the signal measurement circuit; and a hardware processor that positions the conductive probe over a DUT by the motion control system; applies an electrical signal between the conductive probe and the DUT; measures an electrical response from the applied electrical signal; calculates, by the processor, an impedance magnitude value and / or a phase angle value based on the measured electrical response value; moves the conductive probe toward the DUT while continuing to calculate, by the motion control device, an impedance magnitude value and / or a phase angle value from the measured electrical response; determines, by the processor, that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or phase angle value; and signals, by the processor, the motion control device to stop moving the probe toward the DUT based on the change in the calculated impedance magnitude value and / or phase angle value.

[0033] In some embodiments, determining that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or phase angle value includes determining, by the processor, a change in a rate of change of the calculated impedance magnitude value and / or phase angle value.

[0034] In some embodiments, the change in the calculated impedance magnitude value and / or phase angle value includes a value, or an average of the values, a change by a predetermined amount from a baseline, or a match / crossing with an absolute value.

[0035] In some embodiments, the change in the calculated impedance magnitude value and / or phase angle value includes a change in a noise measure, frequency, or profile from a baseline or from matching / intersecting with an absolute measure, frequency, or profile.

[0036] In some embodiments, the change in the calculated impedance magnitude value and / or phase angle value comprises a rate of change that changes from a baseline by a predetermined amount, or that meets / crosses an absolute rate of change.

[0037] Some embodiments may also include performing electrical tests on the DUT.

[0038] Some embodiments may also include determining that electrical testing of the DUT is complete, sending a signal to an operational control device to disconnect the conductive probe from the DUT, and determining, by the processor, that the conductive probe has disconnected from the DUT based on the aforementioned change in the calculated impedance magnitude value and / or phase angle value.

[0039] Some embodiments may also include determining a second DUT to test based on the test plan, and sending a signal to the operation control device to position the conductive probe over the second DUT.

[0040] In some embodiments, placing the conductive probe over the second DUT further includes determining coordinates of the second DUT and placing the conductive probe over the second DUT based on the coordinates of the second DUT.

[0041] In some embodiments, positioning the conductive probe over the second DUT includes determining coordinates of the second DUT and positioning the second DUT under the conductive probe based on a transformation of the coordinates of the second DUT.

[0042] Some embodiments may also include determining a type of DUT based at least in part on comparing the calculated impedance magnitude and phase angle from the received impedance magnitude and / or phase angle values ​​with historical values.

[0043] Some embodiments may also include stopping testing of the DUT before testing of the DUT is completed, measuring an impedance magnitude value and / or a phase angle value, determining that the conductive probe has drifted or moved from the DUT, repositioning the conductive probe to the DUT, and completing testing of the DUT.

[0044] Some embodiments may also include determining, by the processor, that the impedance magnitude value and / or phase angle value indicate proximity between the conductive probe and the DUT, and sending a signal to a motion control device to increase or decrease a speed of movement of the conductive probe toward the DUT based on the proximity between the conductive probe and the DUT determined from the impedance magnitude value and / or phase angle value.

[0045] Some embodiments may also include determining, by the processor, that the impedance magnitude value and / or the phase angle value are indicative of a physical shape of the conductive probe, determining whether the physical shape of the conductive probe is suitable for contacting the DUT based on the impedance magnitude value and / or the phase angle value, and signaling a motion control device to stop and abort processing if the conductive probe does not have a physical shape for contacting the DUT, or signaling a motion control device to continue moving the probe toward the DUT if the conductive probe has a physical shape for contacting the DUT. [Brief description of the drawings]

[0046] [Figure 1A] FIG. 1 is a schematic diagram of components in a system having an automatic probe landing surface according to an embodiment of the present disclosure. [Figure 1B] FIG. 1 is a schematic diagram of components in a system having an automatic probe landing surface according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram of a top view of four nanoprobers on a sample stage in a vacuum chamber of a charged particle beam imaging system according to an embodiment of the present disclosure. [Figure 3A] FIG. 1 is a process flow diagram for landing a probe on a device and testing the device according to an embodiment of the present disclosure. [Figure 3B] FIG. 1 is a swim lane diagram of a probe landing surface treatment according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a process flow diagram for automatic probe landing to a landing location in a charged particle beam according to an embodiment of the present disclosure. [Figure 5A] 1 is a graphical representation of calculated impedance magnitude and phase angle corresponding to probe position relative to a device under test according to an embodiment of the present disclosure. [Figure 5B] 1 is a graphical representation illustrating how the rate of change of calculated impedance magnitude indicates probe tip position relative to the surface of a device under test in accordance with an embodiment of the present disclosure. [Figure 6A] 1 is an image showing an n-type metal oxide semiconductor (NMOS) device source probe landing and testing according to an embodiment of the present disclosure. [Figure 6B] 1 is a graph illustrating an n-type metal oxide semiconductor (NMOS) device source probe landing and testing according to an embodiment of the present disclosure. [Figure 6C] 1 is an image showing an n-type metal oxide semiconductor (NMOS) device source probe landing and testing according to an embodiment of the present disclosure. [Figure 6D] 1 is a graph illustrating an n-type metal oxide semiconductor (NMOS) device source probe landing and testing according to an embodiment of the present disclosure. [Figure 7A]1 is an image showing a p-type metal oxide semiconductor (PMOS) device source probe landing and testing according to an embodiment of the present disclosure. [Figure 7B] 1 is a graph illustrating a p-type metal oxide semiconductor (PMOS) device source probe landing and testing according to an embodiment of the present disclosure. [Figure 7C] 1 is an image showing a p-type metal oxide semiconductor (PMOS) device source probe landing and testing according to an embodiment of the present disclosure. [Figure 7D] 1 is a graph illustrating a p-type metal oxide semiconductor (PMOS) device source probe landing and testing according to an embodiment of the present disclosure. [Figure 8] 1 is a graphical representation of the change in impedance background signal with a change in probe tip profile, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] Unless otherwise noted, figures are not drawn to scale.

[0048] 1A-1B are schematic diagrams of a charged particle beam imaging system including a nanoprober and measurement and control circuitry according to an embodiment of the present disclosure. FIG. 1A shows a nanoprober coupled to a ceiling surface of a vacuum chamber, and FIG. 1B shows a nanoprober coupled to a mounting ring attached to a CPB column. The systems of FIG. 1A and FIG. 1B include a charged particle beam imaging system including a nanoprober and measurement and control circuitry according to an embodiment of the present disclosure.

[0049] FIG. 1A illustrates a first exemplary embodiment of an automated probe landing system 100 and a charged particle beam system 102 according to an embodiment of the present disclosure. The CPB system 102 can be a scanning electron microscope, a focused ion beam system, a combination SEM and FIB, or other type of CPB system for imaging micrometer and nanometer scale structures. The CPB system 102 includes a vacuum chamber 104. The CPB system 102 can include seals, pumps, and other equipment to create a vacuum in the vacuum chamber. The CPB system 102 includes a CPB imaging column 106. The CPB imaging column 106 can emit a charged particle beam, such as an electron beam, a positron beam, or a focused ion beam, toward a target. The CPB system 102 includes an electron detector 108 for detecting electrons as part of the imaging process. Within the vacuum chamber 104 is a sample stage 110 for holding a sample 124. The sample stage 110 can be controllable and trainable to automatically move to position a device under test (DUT) under the CPB imaging column 106. Stated another way, the sample stage 110 is an encoded sample stage 110. The sample stage 110 is also electrically connected to an external electronic system so that the sample stage 110 can function as an electrical return or electrical ground or can be biased. The sample stage 110 can include a return line 126 that can function as an electrical neutral or ground line. The return line 126 can complete a circuit between a conductive probe and a DUT so that a voltage applied to the DUT by the probe can cause a current to flow back through the return line 126 to a signal measurement circuit.

[0050] The DUT may be a circuit element such as a resistor or transistor, or the DUT may be a landing pad or contact pad or other electrode of a circuit element such as a transistor source or transistor drain contact. Any other landing area for making electrical contact to devices or materials on a chip may be referred to as a DUT.

[0051] The automated probe landing system 100 includes one or more nanoprobers 112. The nanoprobers 112 may include any device capable of nanometer or greater (i.e., sub-nanometer) resolution movement. The nanoprobers 112 may have one or more probes 114. The probes 114 may be metal wires (e.g., tungsten wires) that include tapered ends, such as those used in scanning tunneling microscopes or any other conductive material.

[0052] A nanoprober 112 or multiple nanoprobers (as shown) can be used in the CPB imaging system 102 to obtain additional information about the sample. Each nanoprober 112 can be controlled by a motion control system 122. The nanoprober 112 is electrically connected to the motion control system 122 through a vacuum pass-through 116, such as a sidewall of the vacuum chamber or a door of the vacuum chamber. In the embodiment shown in FIG. 1A, the nanoprober 112 can be fixed to the ceiling of the vacuum chamber 104. Typically, the vacuum chamber 104 for a CPB system is a large, heavy piece of equipment that is mechanically stable. Fixing the nanoprober 112 to the ceiling of the vacuum chamber 104 can provide mechanical stability to the nanoprober.

[0053] Briefly referring to FIG. 1B, FIG. 1B is a schematic diagram of a second embodiment of an automatic probe landing system 150 and a charged particle beam system 102 according to an embodiment of the present disclosure. The automatic probe landing system 150 is similar to the automatic probe landing system 100 described herein, but includes a mounting ring 154. The mounting ring 154 can be fixed to the CPB column or can surround the CPB column and be fixed to the ceiling of the vacuum chamber 104. The nanoprober 112 can be fixed to the mounting ring 154. An advantage of the mounting ring 154 is that the vacuum chamber 104 does not need to have mounting holes drilled, which can cause vacuum pressure issues. Instead, the mounting ring 154 can be securely fixed to the CPB column 106 using a bracket or other mechanism. An additional advantage of the mounting ring 154 is that the mounting ring 154 can be configured such that the center of the mounting ring 154 is coaxial with the CPB column 106. The mounting ring 154 can secure the nanoprober 112 at a known, fixed position about an origin that is coaxial with the CPB column and with the charged particle beam itself.

[0054] Returning to FIG. 1A, the motion control system 122 may be directly coupled to the nanoprober 112 or may be connected to the nanoprober through intermediate electronics, such as through the computer system 120. The motion control system 122 may be any type of control system capable of providing electrical signals to the nanoprober to move the nanoprober 112 or move the probe 114. The motion control system 122 may move the nanoprober 112 or move the probe 114 automatically (i.e., without operator input). The motion control system 122 and / or the computer 120 may include software or firmware embodied in a non-transitory medium. The software or firmware may include instructions that, when executed, cause the motion control system 122 to operate the nanoprober 112 to move the probe in one or more directions. For example, the motion control system 122 may respond to electrical information received from the probe 114 indicating that the probe has landed on the surface of the DUT and may stop the movement of the probe toward the DUT. The motion control system 122 may also move the probe up and away from the DUT in response to completion of a test.

[0055] The automatic probe landing system 100 also includes a signal measurement circuit 118. The signal measurement circuit 118 may include circuitry for applying electrical signals to the probe 114 and receiving electrical signals from the sample via the probe 114. The signal measurement circuit 118 may also receive signals via a return line 126. The signal measurement circuit 118 may communicate with the probe 114 via a vacuum pass-through 116. The signal measurement circuit 118 may provide signals to a computer 120 and / or a motion control system 122. For example, raw data from the probe 114 may be routed via the signal measurement circuit 118 to the computer 120, which may calculate a magnitude value of the impedance and / or a phase angle between the voltage and the current (for ease of explanation, the phase angle between the voltage and the current will simply be referred to as the "phase angle"). The impedance and / or phase angle may also be calculated by the signal measurement circuit 118 without departing from the scope of the present disclosure. The signal measurement circuitry 118 can also provide signals to a motion control system 122 , which can use signals from the signal measurement circuitry 118 to automatically control the nanoprober 112 .

[0056] Each of the signal measurement circuitry 118 and the motion control system 122 may be individual hardware units or may be packaged in a single unit, such as part of the computer 120. Any combination of packaging the signal measurement circuitry 118, the motion control system 122, and the computer 120 is contemplated by this disclosure. Additionally, although not shown, one or both of the signal measurement circuitry 118 or the motion control system 122 may be implemented using circuitry that is on, with, or in close proximity to the nanoprober 112. The nanoprober 112 may also be powered using a battery or other modular power source. Such an implementation choice reduces the number of external cables used for signal measurement, nanoprober control, and power supply.

[0057] The computer 120 may include one or more hardware processors, memory, storage, and peripheral components including user interface components such as a mouse, keyboard, monitor, joystick, or other type of user interface. The computer 120 may include software that allows an operator to control the CPB system 102. The monitor can be used to view images produced by the CPB system 102, including real-time imaging of the nanoprober 112 operation. The computer 120 may include hardware and software for performing signal measurements, performing signal calculations, running tests, automating the nanoprober, storing information, and performing other tasks related to automated probe movement and landing and device testing. The computer 120 may include signal measurement circuitry and operation control hardware and software as described herein.

[0058] FIG. 2 is a schematic diagram of a top view of four nanoprobers on a sample stage in a vacuum chamber of a charged particle beam imaging system according to an embodiment of the present disclosure. FIG. 2 shows a top view of the automatic probe mounting system of FIG. 1A or FIG. 1B. The automatic probe mounting system includes four nanoprobers 112a-112d. Each nanoprober 112a-112d includes a coarse positioner 202 and a fine positioner 204. Each of the coarse positioner 202 and the fine positioner 204 can be controlled by a motion control system 122. The motion control system 122 can control the coarse positioner 202 and the fine positioner 204 to move in the X-direction, the Y-direction, or the z-direction. (Those skilled in the art will know that other coordinate systems, such as polar coordinates, can be used to describe physical space and movement within physical space).

[0059] As shown in Figure 2, a nanoprober has coarse motion in the X, Y, and Z directions. Coarse motion can be achieved using actuators. A nanoprober also includes fine motion in the X, Y, and Z directions. Fine motion can be achieved using piezoelectric materials. Other mechanisms for coarse and fine motion can be used as long as each is vacuum compatible and achieves the desired motion resolution.

[0060] In an embodiment, the motion control system 122 can be manually operated. When manually operated, an operator provides control commands or signals to the nanoprober via a control interface, such as a joystick, mouse, keyboard, smart device, or other interface. The motion control system can convert the operator's signals into electrical signals that actuate fine or coarse movements of the nanoprober.

[0061] The nanoprobing system, located within the CPB imaging system, relied on humans to control the position of each probe. An operator, visually watching a live (e.g., SEM) image on a display, moves the probe using software control or a hardware controller. This type of control is "open loop" and the operator completes the targeting. Essentially, the operator sees the target for the contact point in the CPB imaging system image and sees the tip of the probe in the same image. The operator then provides input to the control software using a joystick, mouse movements, or other controller to move the probe to contact the target point.

[0062] Manual probing for in situ testing of semiconductor devices is a time-consuming and labor-intensive process. This disclosure describes a system and apparatus for automating the probe landing procedure so that in situ testing of single digit nanometer feature sizes can be accomplished without manual manipulation of a probing device.

[0063] As shown in Figures 1-2, a nanoprobing system located within the CPB imaging system can apply electrical signals to the probe. The nanoprobing system can measure the electrical response during the probe landing and lifting procedures and perform device testing. For example, the nanoprobing system can apply a voltage and measure the current (or apply a current and measure the voltage) during the probe landing procedure. The resulting impedance magnitude measurements and impedance phase angle measurements can be used to determine the height of the probe from the surface target and can be used to determine if the probe has landed on the target. Automation of the probe landing (and device testing) procedure can be achieved by using a closed-loop design, increasing throughput (or reducing time) while reducing labor costs. Automation can also make it easier to test more devices on a single chip in less time, and more chips overall.

[0064] 3A is a high level process flow for automated probe deposition on a device and device testing according to an embodiment of the present disclosure. It is understood that the automated probe deposition and device testing embodiment can be performed in a CPB imaging system under vacuum conditions. However, automation of probe deposition and device testing can be performed in any environment without departing from the scope of this disclosure. It is also understood that the deposition process is automated. One or more method operations are performed by one or a combination of a computer system, a signal measurement system, a motion controller, and a nanoprober device.

[0065] In FIG. 3A, first, a device under test (DUT) may be moved to a predetermined location in the vacuum chamber (302). For example, a sample stage supporting a chip containing the DUT may be positioned such that the DUT is located at a predetermined location in the CPB chamber. The predetermined location may be known or determined from CAD layout information. For example, the chip on which the DUT is fabricated may have a corresponding CAD map that includes coordinate or position values ​​for each device on the chip. This information may be used by an automated system to place the sample stage at a predetermined location. This predetermined location may be the "origin" of the CPB coordinate system and may coincide with the CPB. In an embodiment, the predetermined location may be any location within one or both of the scanning range of the CPB or the position range of the nano-probing system.

[0066] The nanoprobing system may have a coordinate system that may be mapped to a coordinate system of the CPB system such that the probe locations and the DUT locations are transposed to a common coordinate system. This transposition is beyond the scope of this disclosure. The nanoprober system may position the conductive probe in an X-direction and a Y-direction above the DUT (304). For example, a control system may use the coordinate system mapping to move the probe tip to a predetermined location in the X-direction and the Y-direction such that the conductive probe is above the DUT.

[0067] Prior to lowering the probe in z towards the DUT and during the landing process, measurements of the impedance magnitude and / or phase angle can be performed (306). The impedance magnitude and phase angle measurements are calculated by measuring the current. A voltage is applied across the probe and a current is measured between the probe and the sample stage. The impedance may include a resistance and / or a capacitance value. The probe is moved towards the DUT. Those skilled in the art will know that a current can be applied and a voltage can be measured. The impedance magnitude and phase angle measurements can be calculated from the measured voltage.

[0068] As the probe moves towards the DUT, impedance magnitude and phase angle values ​​are calculated and proximity information between the probe tip and the contact location is monitored. As the tip approaches the contact location, the rate of change of the impedance measurement begins to increase. Detection of the increase in the rate of change of the impedance measurement can be used to control the speed of movement of the probe tip towards the contact location.

[0069] When the distance between the probe tip and the DUT is large, the rate of change of the impedance magnitude and phase angle will be relatively small (e.g., no change is observed or the observed rate of change is slow). An increase in the rate of change of the impedance magnitude value and / or phase angle indicates to the probing system that the probe is approaching the DUT surface. The rate of change of the impedance magnitude value and / or phase angle value can be used to control the direction of movement of the probe tip. For example, the motion control system can move the probe tip towards the DUT surface while no change in the rate of change of the impedance magnitude value and / or phase angle value is observed. The motion control system can stop movement of the probe tip when an abrupt change in the rate of change of the impedance magnitude value and / or phase angle value is observed.

[0070] Additionally, the motion control system can control the speed of the probe tip based on the observed rate of change of the impedance magnitude and / or phase angle values. For example, the motion control system can move the probe tip quickly toward the DUT surface when little or no change is observed in the rate of change of the impedance magnitude and / or phase angle values. The motion control system can slow the speed of movement of the probe tip toward the DUT surface when a particular change is observed in the rate of change of the impedance magnitude and / or phase angle values. Slowing the probe tip provides a gentler landing on the surface and maintains the integrity of the probe tip with the DUT surface.

[0071] Impedance values ​​are also monitored for information on the suitability or quality of the probe tip for contacting the sample. As the probe tip approaches the contact location, the overall background trend of the impedance values ​​indicates the shape of the conductive probe tip. A very flat or constant background trend indicates a sharp tip with a very small tip radius. A non-constant, slightly sloping background may indicate a conductive probe tip with a large tip radius, and a larger background slope may indicate landing with the probe contact point further up the probe from the tip, where the probe tip bends away from the sample. In the last two situations, the automated probe landing sequence may determine that the probe is not suitable for use, abort the landing process, and alert the operator that the probe should be changed or replaced.

[0072] When the impedance magnitude and / or phase angle values ​​show a change, it is determined that the probe has landed and the control system stops the probe. The change can be a change from an acquired baseline, or an impedance component measuring a value or a moving average that meets / crosses a set absolute value. The change can also be other behaviors of the electrical signal, such as a change in the measured noise or the frequency of the noise.

[0073] In one non-limiting example, thresholds may be used by a control system to determine the landing surface of the probe and control the movement of the probe tip. For example, a non-contact electrical response may provide a first impedance magnitude value Z1 and a first impedance phase angle value θ1. An electrical response after the probe lands on the surface of the DUT may provide a second magnitude Z2 and a second phase angle θ2. A threshold landing surface magnitude Zt may be defined as Z1>Zt≧Z2. A threshold landing surface phase angle θt may be defined as θ2≧θt>θ1. Multiple thresholds may be set to define soft and hard contacts on the surface. A threshold magnitude Zsc and threshold Zhc for the soft landing surface may be defined as Z1>Zsc>Zhc, and Z2 may represent either a soft or hard landing surface depending on the value of Z2 and the thresholds Zsc and Zhc. A threshold phase angle θsc for a soft landing surface and a threshold phase angle θhc for a hard landing surface may be defined as θhc>θsc>θ1, where θ2 may represent either a soft landing surface or a hard landing surface depending on the value of θ2 and the thresholds θsc and θhc. Other thresholds may also be identified and stored. For example, a threshold rate of change of impedance may be determined and stored. The rate of change of impedance threshold may be used to determine whether a rate of change of impedance determined from a signal measurement indicates that the probe is approaching the surface of the DUT.

[0074] The thresholds may be stored and used during the probe landing procedure. For example, in one exemplary embodiment, the computer may determine and store one or more thresholds for the rate of change of impedance. Because the nanoprober system continuously measures impedance, the processor may calculate the rate of change of the measured impedance. The calculated rate of change of impedance may be compared to a threshold rate of change of impedance to determine the proximity of the probe to the surface of the DUT as the probe moves toward the surface of the DUT. If the processor determines that the rate of change of impedance is equal to or greater than a first threshold rate of change of impedance, the computer may determine that the probe is within a predetermined distance from the surface and may signal the motion control system to slow down the movement of the probe. If the processor determines that the rate of change of impedance is equal to or greater than a second threshold rate of change of impedance, the computer may determine that the probe has contacted the surface and may signal the motion control system to stop the movement of the probe.

[0075] After the DUT is positioned and the probe is positioned in the X and Y directions, the probe can be lowered in Z toward the DUT, either manually or automatically (308). In particular, the symbol Z is used for both impedance and directionality. For clarity, a lowercase z is used to indicate directionality. The z direction is orthogonal to the X and Y directions of a Cartesian coordinate system, where the z direction is toward or away from the sample stage. The coordinate system is shown in FIG. 2. The control system can apply a ramped control signal to move the probe in Z toward the DUT. In an embodiment, initially the nanoprober can move in large steps to cover a relatively large distance. As the probe approaches the surface, the steps become gradually or suddenly smaller. At some point or after a time when the system performs impedance and phase angle measurements, the nanoprober moves the probe in smallest increments toward the surface.

[0076] As the probe moves in z towards the DUT, the system can determine whether the resulting impedance magnitude value and / or phase angle value calculations indicate that the probe has landed on the DUT surface (310). Once the probe has landed, a stop signal is sent to the control system to stop the movement of the probe. In some embodiments, it may be beneficial to verify ohmic contact before acquiring test data. The probe can be lifted and re-landed (again, using impedance magnitude and phase angle calculations). After the impedance magnitude value and / or phase angle value calculations indicate the probe has landed, the probe can also be moved further in z towards the DUT to verify that ohmic contact is reached.

[0077] The DUT is tested and data is collected (314). In an embodiment, part of the probe landing and test automation includes training the system to recognize good DUT test results. Training can also be used to distinguish between faulty DUTs and poor or failed probe contacts on the DUT. Because the tests are intended to be performed automatically without operator observation, the system can automatically determine whether the test was performed successfully and whether the test resulted in a pass or fail for the DUT.

[0078] First, each DUT can have an associated theoretical electrical response. For example, a resistor has a theoretical resistance that, within a margin of error, will draw a predictable current in response to an applied voltage. The theoretical electrical response is called the characteristic operating parameters. Each DUT can include a set of one or more characteristic operating parameters against which observed data can be compared. If the observed data matches the characteristic operating parameters, the DUT is deemed to pass. If the DUT is deemed to pass, the system can move on to the next DUT by either moving the probe or moving the sample, or both.

[0079] If the observed data does not match the characteristic operating parameters, the system can determine if the DUT has failed or is defective, or if the probe landing has failed. After a DUT has failed, a number of implementation-specific options are available.

[0080] In some embodiments, the probe can be lifted and the DUT can be tested again. If the DUT fails again, the system can log the failure and move on to the next DUT. The electrical response of a failed DUT may simply be outside of characteristic operating parameters. Additionally, the electrical response of a failed DUT may be associated with one or more fault electrical responses. For example, a shorted resistor may produce a fault electrical response IV curve (such as a vertical line through the origin). These fault electrical responses can be used to confirm that the DUT is defective and to determine what the defect is.

[0081] The electrical response of these faults may be different than the electrical response due to a failed probe landing (which may be a probe that does not land on the DUT or does not make ohmic contact with the DUT when landed). Therefore, the electrical response observed during testing can be used to determine if the DUT has failed or is defective, or if the probe tip is not properly landed on the DUT, allowing for proper testing.

[0082] If the DUT is not the first DUT that failed, other considerations can be taken into account: An alert can be sent to the operator so that the DUT can be manually tested. The operator can manually retest the DUT to ensure that the probe tips are contacting the correct DUT and that the test is being performed properly. The operator can manually retest other DUTs to ensure that the tests are being performed properly. The operator can also conclude that the specimen is bad and begin testing a new specimen.

[0083] The electrical response from the test can be used to determine that the probe did not land properly on the DUT. For example, an intermittent signal response or high noise levels may suggest poor ohmic contact to the DUT. Landing on an oxide or other insulating layer may also have a characteristic electrical response (such as an I-V curve) that indicates a failed landing. Landing on another circuit component (the wrong DUT) may produce an indicative electrical response. For example, an I-V response from a resistor will be different than an I-V response from a transistor. If the probe fails to land, it is lifted and the landing process is retried. Of note, in some cases, a failed probe landing can lead to damage to the probe. In some cases, a failed probe landing may result in a retry of the landing with a different probe (e.g., from another nanoprober in the vacuum chamber). An operator can take an image of the probe to determine if damage has occurred. In some circumstances, an operator can manually change the probe.

[0084] Once the DUT test is complete, the probe is lifted (316). Probe lifting is automated and triggered by the completion of the DUT test. For example, a control system may automatically lift the probe after a certain amount of data has been acquired. The probe is lifted high enough from the tip to allow the stage to be moved without the probe inadvertently contacting features on the tip. Impedance and phase angle are measured while the probe is lifted to ensure a sufficient distance from the surface. The process can then resume with the next DUT. In some cases, the next DUT is close to the previous DUT and so there is no need to move the stage. Instead, the probe is positioned in X and Y. If the next DUT is far enough away, the stage is moved to place the next DUT in place.

[0085] If a DUT is detected to be defective, the automatic probe landing device can perform defect verification by going back to the previous DUT and running the test again on the previous DUT. If the results of the previous DUT test are the same or similar as before, the defect detected on the next DUT is not due to the probe. In some cases, if a defect is detected, the system can either alert the operator or log the defect and move on. The operator can choose to visually inspect the DUT, manually land the probe, and run the test to verify the defect. These options are implementation specific.

[0086] FIG. 3B is a swim-lane diagram 350 of a probe landing process according to an embodiment of the present disclosure. The swim-lane diagram 350 illustrates signal exchanges between various components of the system. For example, initially, the signal measurement circuitry 118 can apply a voltage between a conductive probe and a sample stage supporting the DUT (352). The signal measurement circuitry 118 can measure an electrical response from the DUT (354). The signal measurement circuitry 118 (or other component capable of performing signal analysis and calculations) can calculate an impedance magnitude value and / or a phase angle value from the received electrical response (356). The calculated impedance magnitude and phase angle values ​​can be compared to thresholds to determine whether the probe is approaching the DUT surface or whether the probe has landed. This process 352-358 can be performed until the signal measurement circuitry 118 (or other calculation component) determines that the probe has landed on the surface. (FIG. 5A illustrates how the impedance magnitude and phase angle change based on the proximity of the probe to the DUT surface). The impedance magnitude and phase angle thresholds for defining contact vs. no contact can be empirically predetermined for each DUT type, and the threshold magnitude and phase angle values ​​for defining light / soft or intermittent contact can also be empirically predetermined for each DUT type.

[0087] After the signal measurement circuitry begins measuring the electrical response from the probe, the motion control system 122 can begin moving the probe in the z-direction toward the DUT (362). The motion control system 122 can signal a coarse positioner (e.g., 202) of the nanoprober 112a (or other nanoprobers described herein) to move the probe toward the DUT. After a certain number of steps or a certain amount of time, the motion control system 122 can signal the coarse positioner to stop and can signal the fine positioner to move the probe in the z-direction toward the DUT. The details regarding the movement of the probe in z are implementation specific.

[0088] The motion control system 122 controls the z-direction movement of the probe based at least in part on the electrical response from the probe. The motion control system 122 can continue to move the probe in the z-direction toward the DUT until the electrical response from the probe indicates that the probe has landed (366). That is, when the calculated impedance magnitude value and / or phase angle value meet or cross a threshold value. In some cases, the electrical response from the probe can indicate that the probe has nearly landed or has "softly" landed (368). A soft landing is when the probe is in physical contact with the DUT surface but sufficient ohmic contact is not established to perform electrical testing of the DUT. In such cases, the motion control system 122 can slow the approach to avoid the probe colliding with the surface of the DUT and risking damaging the probe and / or the surface. In the case of a soft landing, the electrical response from the probe can alert the motion control system to slow the z-direction movement or to stop the z-direction movement and resume the z-direction movement at a slower rate. Figure 5A shows the light-touch electrical response for both magnitude and phase angle. Figure 5A also shows how the electrical response can change as the motion control system 122 continues to move the probe in the z-direction after soft landing is achieved to establish hard (or ohmic) contact with the surface of the DUT.

[0089] If the impedance magnitude value and / or phase angle value thresholds are met or exceeded, an alert can be issued to the motion control system to stop the probe moving in the z-direction (366). If the impedance magnitude value and / or phase angle value thresholds are met or exceeded, resulting in the probe stopping motion, the system can be triggered to start testing the DUT (370). The signal measurement circuit 118 can be responsible for electrical testing of the DUT. The signal measurement circuit 118 can receive instructions, for example, from a computer system or controller, to perform one or more tests specific to the DUT. For example, based on a CAD map of the chip and a test plan implemented by the controller, the system knows what the DUT is and what type of test is to be performed on the DUT. The DUT and the associated test plan can be stored in memory and accessed each time a test is performed. Additionally, the test results can also be stored in memory along with information relating the test result data to the corresponding DUT.

[0090] If the DUT passes the test (372), the passing test result for the DUT may alert the motion control system to lift the probe off the surface of the DUT (374). If the DUT fails the test (376), any number of implementation specific actions may be taken, including retesting (376), recording the failure by the DUT (378), retrying the probe landing as described above, etc. However, at some point the system will transition out of testing the DUT by having the motion control system 122 lift the probe off the DUT in the z-direction (374).

[0091] FIG. 4 is a process flow diagram illustrating the process of using impedance magnitude (Z) and phase angle (θ) measurements to determine when the probe has landed on a surface. First, reference and trigger (or threshold) values ​​for the device under test (DUT) can be determined (402). For example, impedance magnitude and phase angle values ​​can be measured while the probe is off the sample and after the probe has been manually (or automatically) touched down on the sample (404). Sufficient impedance magnitude and phase angle values ​​are calculated (406) for both the probe landing and probe lift scenarios so that an average value can be calculated (408). The amount of data collected for sufficient averaging is implementation specific. Averaging can also be skipped. Reference values ​​for the impedance magnitude and phase angle measurements can be used to determine when the probe has left the sample and when it has landed on the sample (410). Thresholds for a particular DUT can be saved for later use in probe landing and validation. A library of thresholds can be saved as a reference for each device or material.

[0092] When testing a particular device, the autoprobe landing device can either establish thresholds for that device or use stored values ​​as thresholds. Additionally, different landing scenarios can be profiled for each DUT. For example, the electrical response of a soft landing can be profiled to establish a soft landing criteria and trigger (or threshold).

[0093] In an exemplary embodiment, for any DUT, various electrical data can be collected and recorded during a preliminary characterization step during real-world operation of the probing system. Examples of electrical data include, among others, the signal-to-noise ratio (SNR) or SNR standard deviation experienced and measured upon landing of the probe, the rate of change of impedance magnitude and phase angle, the standard deviation of the rate of change of impedance magnitude and phase angle, the impedance magnitude and phase angle, and the standard deviation of the impedance magnitude signal or the standard deviation of the phase angle.

[0094] Contact measurement probes of many DUTs, including various DUT variations, can be performed and the results recorded. The DUT probe data can be compared to, for example, the signal-to-noise ratio of the probing system, or other electrical data. These recorded system noise values ​​and the DUT comparison data can be used to calculate a predetermined quantity that defines a sensitivity threshold or rate of change threshold that determines when the conductive probe has contacted the DUT.

[0095] Other metrics may also be observed or calculated and may be used to determine when the probe is approaching the surface, when the probe has landed, when the probe has drifted from the surface, and when the probe has been damaged. For example, the calculated impedance magnitude and / or change in impedance may include matching / crossing a value, or an average of values, a change of a predetermined amount from a reference, or an absolute value. The calculated impedance magnitude and / or change in impedance may include a noise measure, frequency, or profile change from a reference, or matching / crossing an absolute measure, frequency, or profile. The calculated impedance magnitude and / or change in impedance may include a rate of change that changes a predetermined amount from a reference, or a rate of change that matches / crosses an absolute rate of change.

[0096] A library of electrical information regarding the probe landing surface can be created for various devices. The magnitude and rate of change of the impedance of the DUT and the phase angle can be determined during testing and stored for each device. These values ​​can be used during operation as criteria, benchmarks, triggers, thresholds, etc. that the motion control system uses to determine if the probe has successfully landed on the surface of the DUT.

[0097] Historical data can be collected, updated, and refined over time through shared data and ongoing testing using data determined during operation of the system. Historical data can also be used to train the motion control system, for example, using machine learning training algorithms. The motion control system can be continually improved with each successful (and failed) landing.

[0098] Each time a probe is landed on a particular device, the observed and calculated electrical response information for the probe landing may be stored (for both successful and unsuccessful landings). As an example, for the first device, the calculated impedance magnitude and rate of change of phase angle may be stored. The rate of change information may be used to calculate thresholds or other information for future probe landings on the same or similar devices. The electrical information is refined over time with each successful probe landing using machine learning techniques or other algorithms. Machine learning techniques or other algorithms may be used to refine thresholds or benchmarks or triggers used to control probe movement during probe landing of a device. Using historical data to refine expectations, thresholds, benchmarks, etc. for controlling probe movement increases successful landings, thereby speeding up testing, reducing costs and increasing throughput.

[0099] Electrical response information from failed landings can also be used to refine the electrical information used for future probe landings on the same or similar devices. For example, electrical information from failed landings can be used to filter false positives and reduce future unsuccessful landings. A control system can be trained to recognize "bad" data. The control system can stop probe movement prior to landing, reposition the probe, and start over. Or, the control system can alert an operator that bad data was detected. In either case, preventing failed landings can save time and reduce the chance of damaging the probe tip or surface features.

[0100] Impedance magnitude and phase angle criteria can be obtained to distinguish between soft and hard landings. A soft landing is characterized as the probe touching the surface, the contact is light or soft, and the impedance is not yet stable. A hard contact is characterized as a mechanical push down where the impedance is stable. The difference between soft and hard contacts can be used to 1) establish the touchdown point, 2) continue moving the probe towards the target and firmly establish ohmic contact with the DUT, and 3) prevent the probe from crashing into the landing surface, which could damage the surface or the probe itself. An example of electrical measurements of soft and hard landings is shown in Figure 5A. An automated probe landing system can use the impedance magnitude and phase angle measurements to ensure contact quality, which improves the reliability of DUT electrical testing.

[0101] The reference impedance magnitude and phase angle values ​​can be used as triggers (or thresholds) for automated systems. For example, the threshold magnitude and / or phase angle values ​​can be used to determine when the probe controller should stop moving the probe towards the DUT. The reference values ​​can also be used when evaluating probe drift. For example, to the extent that the probe drifts from the DUT, the reference values ​​can be used to determine that the probe has moved away from the DUT and to reset the probe to the DUT.

[0102] The reference values ​​may include characteristic operating parameters of the DUT, such as those resulting from passing electrical tests. The reference values ​​may be specific to a particular structure or material, so that the reference values ​​can be used to verify that the probe landed on the intended target as opposed to a different structure on the surface.

[0103] The change in impedance magnitude and / or phase angle values ​​after landing (at contact) can be used as a stability control at contact by constantly monitoring the magnitude and / or phase angle measurements to correct for drift / creep. The change in magnitude and / or phase angle values ​​can also be used as a measurement of contact quality / verification.

[0104] Additionally, reference and trigger values ​​can be determined and stored to allow probe landing on oxide layers or other surfaces other than the DUT, providing the system with information on mis-deposition or failed landings.

[0105] The baseline values ​​can also be used to verify that the probe landed on the DUT and not elsewhere. In addition to location verification, the impedance magnitude and phase angle values ​​can also be used to verify the structure. For example, a structure with certain dimensions may have a different impedance response than certain other structures. Using knowledge of the DUT's dimensions, configuration, and electrical properties, baseline values ​​for the impedance magnitude and phase angle can be established, which can be used to verify that the probe contacted the correct DUT. Figures 6 and 7 show how NMOS and PMOS devices exhibit different magnitude and phase angle responses during the landing process.

[0106] After the DUT is placed in a predetermined desired position (e.g., the CPB origin), the probe can be positioned in X and Y so that it is above the DUT. Impedance magnitude and phase angle measurements can begin to be made at this point before beginning the downward (z) movement of the probe towards the DUT.

[0107] The probe moves towards the DUT while checking for a trigger (412). The motion control system moves the probe in the z-direction towards the DUT (414). Signal measurement circuitry measures the electrical response from the probe and calculates the impedance magnitude and phase angle so that it can determine whether to continue moving towards the surface or stop moving (416). When one or both of the measured magnitude or phase angle values ​​meet or exceed thresholds established by the reference measurements (418), the control system can stop the z-movement of the probe (420).

[0108] Verification data can be acquired to confirm that the probe is in contact with the surface (422). Collecting the verification data can include receiving an electrical response from the probe after landing and calculating impedance magnitude and / or phase angle values ​​(424). The verification data can be acquired a sufficient number of times to confidently conclude that the probe has landed on the target surface (426). If verification fails, the probe can be lifted, the XY position of the probe can be changed, and the probe landing process can be resumed. In some embodiments, if verification fails, CPB image data can be acquired to visually inspect the position of the probe. This image-based verification is outside the scope of this disclosure.

[0109] Once it is verified that the probes have been landed on the DUT, DUT testing can begin. Examples of DUT testing are shown in Figures 6A-6D and 7A-7D. Figures 6A-6D show the process and data for landing the probes and performing DUT measurements on an exemplary NMOS device according to an embodiment of the present disclosure. Figures 7A-7D show different probe landing and DUT measurements on an exemplary PMOS device according to an embodiment of the present disclosure.

[0110] FIG. 5A is a graphical representation of measured impedance and phase angle corresponding to probe position relative to a device under test according to an embodiment of the present disclosure. The dots on the graph represent Z and θ values. The Z and θ measurements can be provided to a control system that can automate the probe landing and movement sequence. FIG. 5 shows the change in impedance magnitude and phase angle as the probe moves from above the surface until the probe contacts the surface. In FIG. 5, a sample is used to average the magnitude and phase angle over time. In FIG. 5, between 0 and time t1, the probe is not in contact with the DUT. The magnitude is high while the probe is moving towards the DUT. At time t1, when the probe contacts the surface, a rapid rate of change in impedance magnitude and phase angle occurs. The magnitude and phase angle remain substantially constant during the contact period from t1 to t2.

[0111] When the probe is lifted at t2, the rate of change of the magnitude and phase angle of another impedance increases, and the magnitude and phase angle values ​​return to their previous non-contact levels. At time t3, the probe touches down again and there is another discontinuity in the magnitude and phase angle.

[0112] FIG. 5A also shows a soft contact situation, where there is a smaller discontinuity in the impedance magnitude and phase angle at time t4. However, the measured magnitude and phase angle levels are different for soft and hard contact (e.g., the magnitude and phase angle at time t4 are different from time t1). As the probe moves down in z after contact (the initial smaller discontinuity), the magnitude and phase angle change gradually over time between t4 and t5, as opposed to one sudden large discontinuity. The magnitude and phase angle reach relatively constant levels after time t5, which coincides with the large discontinuity at t1. At time t6, the probe is lifted again.

[0113] Between times t3 and t4, the probe is landed and lifted in rapid succession to show how the impedance magnitude and phase angle change due to probe drift, thermal effects, or other conditions.

[0114] The above process can be used to land one or more probes, for example landing multiple probes to enable different DUT test scenarios.

[0115] FIG. 5B is a graphical representation 500 illustrating how the rate of change of the calculated impedance magnitude indicates the tip position of the probe relative to the surface of the device under test, according to an embodiment of the present disclosure. Similar to FIG. 5A, FIG. 5B is organized by time period. During the period t1 to t2, the tip of the probe may be stationary or moving towards the DUT. Starting at time t2, a small rate of change of the impedance magnitude is observed, indicating that the tip of the probe is approaching the surface of the DUT. The rate of change of the impedance magnitude during t2 to t3 may trigger a control system to slow down the speed of the tip of the probe as it approaches the surface. Starting at time t3, the rate of change of the impedance magnitude increases compared to the value calculated during the period t2 to t3. The rate of change of the impedance magnitude that increases during t3 to t4 may indicate that the tip of the probe is moving more slowly than during the period t2 to t3. The tip of the probe makes contact with the surface at time t4. This is shown as a very high rate of change of the impedance magnitude. From t5 to t6, the tip of the probe touches down on the surface of the DUT.

[0116] In some embodiments, a bias can be applied to the probe tip during landing to combat noise in the signal measurement.

[0117] As mentioned briefly earlier, measurements of the impedance magnitude and / or phase angle values ​​can be used to determine the surface and material that the probe has landed on. They can be used to verify that the probe has landed in the right place by distinguishing between dielectric and metallic or semiconducting structures. They can also distinguish between NMOS and PMOS structures, as shown in Figures 6 and 7.

[0118] 6A-6D are images and graphs illustrating an n-type metal oxide semiconductor (NMOS) device source probe landing and testing according to an embodiment of the present disclosure. The dots on the graphs represent Z and θ values. FIG. 6A is a diagram 600 showing a probe 602 hovering over a chip 604 containing multiple devices. The landing target 606 is the source contact of an NMOS device. (The DUT in this example is an NMOS device in general, and specifically, the source contact of an NMOS device). FIG. 6B is a diagram 610 showing the calculation of the magnitude and phase angle of the impedance of an NMOS source before and after landing the probe 602 on the source contact 606. As can be seen, a data point is collected before moving the probe in the z direction towards the source contact 606. At time t1, the probe 602 is lowered towards the DUT. The magnitude and phase angle are outside of their respective trigger values ​​before and during the time that the probe 602 moves towards the DUT. At time t2, the probe 602 contacts the source contact 606. FIG. 6C is a diagram 620 showing the probe 602 facing the source contact 606. It can be seen that at time t2, the magnitude drops and quickly crosses the trigger value, and the phase angle increases and also quickly crosses the trigger value. The magnitude and phase angle discontinuities advantageously provide a fast trigger to stop the movement of the probe 602. As shown in FIG. 5A, the magnitude and phase angle discontinuities are repeatable. The probe 602 can then be used to test an NMOS device through the source contact. This is shown in FIG. 6D. FIG. 6D is a graph 630 showing the drain current in response to a voltage applied to the NMOS source.

[0119] 7A-7D are images and graphs illustrating p-type metal oxide semiconductor (PMOS) device source probe landing and testing according to an embodiment of the present disclosure. FIG. 7A is a diagram 700 showing a probe 702 hovering over a chip 704 containing multiple devices. The landing target 706 is the source contact of a PMOS device. (The DUT in this example is a PMOS device in general, and the source contact of a PMOS device in particular). FIG. 7B is a diagram 710 showing the calculation of the magnitude and phase angle of the impedance of a PMOS source before and after landing the probe 702 on the source contact 706. As can be seen, a data point is collected before moving the probe in the z-direction towards the source contact 706. At time t1, the probe 702 is lowered towards the DUT. The magnitude and phase angle are outside of their respective trigger values ​​before and during the movement of the probe 702 towards the DUT. At time t2, the probe 702 makes contact with the source contact 706. FIG. 7C is a diagram 720 showing the probe 702 facing the source contact 706. It can be seen that at time t2, the magnitude drops, quickly crossing the trigger value, and the phase angle increases, also quickly crossing the trigger value. The magnitude and phase angle discontinuities advantageously provide a fast trigger to stop the movement of the probe 702. As shown in FIG. 5A, the magnitude and phase angle discontinuities are repeatable. The probe 702 can then be used to test a PMOS device through the source contact. This is shown in FIG. 7D. FIG. 7D is a graph 730 showing the drain current in response to a voltage applied to the PMOS source.

[0120] In some embodiments, signal noise, impedance magnitude, and impedance phase angle can be used to achieve detection of discontinuity or approach prior to landing detection. This approach detection can be used to slow probe movement to achieve a soft landing.

[0121] FIG. 8 is a graphical representation of the change in impedance background signal due to changes in the probe tip profile, according to an embodiment of the present disclosure. The background signal from the impedance magnitude calculation (and phase angle, although not shown) can be indicative of the geometric condition of the probe tip itself. A probe tip with a small radius of curvature, such as a new sharp probe tip, may be indicated by an impedance background signal that does not change or does not change rapidly over time. A probe tip with a large radius of curvature may have a small rate of change in the impedance background signal. Also, a damaged probe tip (such as a curled or flat tip) may have a higher rate of change in the impedance background signal compared to a tip with a large or small radius of curvature.

[0122] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0123] The term "communicating" as used within this document is intended to include transmitting, receiving, or both transmitting and receiving. This may be particularly useful in claims when describing the configuration of data transmitted by one device and received by another, although only one function of those devices is necessary to infringe a claim. Similarly, a two-way exchange of data between two devices (both devices transmitting and receiving during the exchange) may be described as "communicating" if only one function of those devices is claimed. The term "communicating" as used herein with respect to wireless communication signals includes transmitting wireless communication signals and / or receiving wireless communication signals. For example, a wireless communication unit capable of communicating wireless communication signals may include a wireless transmitter for transmitting wireless communication signals to at least one other wireless communication unit, and / or a wireless communication receiver for receiving wireless communication signals from at least one other wireless communication unit.

[0124] As used herein, unless otherwise specified, the use of ordinal adjectives such as "first," "second," "third," etc. to describe a common object merely indicates that different instances of a similar object are being referred to, and does not imply that the objects so described must be in a particular order in time, space, ranking, or in any other manner.

[0125] Some embodiments may be used with a variety of devices and systems, such as a personal computer (PC), desktop computer, mobile computer, laptop computer, notebook computer, tablet computer, server computer, handheld computer, handheld device, personal digital assistant (PDA) device, handheld PDA device, on-board device, off-board device, hybrid device, in-vehicle device, non-in-vehicle device, mobile or portable device, consumer device, non-mobile or non-portable device, wireless communication station, wireless communication device, wireless access point (AP), wired or wireless router, wired or wireless modem, video device, audio device, audio-video (A / V) device, wired or wireless network, wireless area network, wireless video area network (WVAN), local area network (LAN), wireless LAN (WLAN), personal area network (PAN), wireless PAN (WPAN), and the like.

[0126] Some embodiments may be implemented using one-way and / or two-way wireless communication systems, cellular radiotelephone communication systems, mobile phones, cellular telephones, wireless telephones, personal communication system (PCS) devices, PDA devices incorporating wireless communication devices, mobile or portable global positioning system (GPS) devices, devices incorporating GPS receivers or transceivers or chips, devices incorporating RFID elements or chips, multiple input multiple output (MIMO) transceivers or devices, single input multiple output (SIMO) transceivers or devices, single input single output (SISO) transceivers or devices, multiple input single output (MISO) transceivers or devices, devices with one or more internal and / or external antennas, digital video broadcast (DVB) devices or systems, multi-standard radio devices or systems, wired or wireless handheld devices, such as smartphones, wireless application protocol (WAP) transceivers, and the like. It may be used in conjunction with a IEEE 802.11b (protocol) device, etc.

[0127] Certain aspects of the present disclosure are described above with reference to block diagrams and flow diagrams of systems, methods, apparatuses, and / or computer program products according to various implementations. It will be understood that one or more blocks of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and flow diagrams, respectively, may be implemented by computer-executable program instructions. Similarly, according to some implementations, some blocks of the block diagrams and flow diagrams may not necessarily be performed in the order presented, or may not necessarily be performed at all. Certain aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, all of which may be generally referred to herein as "services," "circuits," "circuitry," "modules," and / or "systems."

[0128] The computer-executable program instructions may be loaded into a special-purpose computer or other specific machine, processor, or other programmable data processing apparatus to produce a specific machine, such that the instructions executed on the computer, processor, or other programmable data processing apparatus create means for implementing one or more functions specified in one or more blocks of the flow diagram. These computer program instructions may also be stored in a computer-readable storage medium or memory that causes the computer or other programmable data processing apparatus to function in a specific manner, such that the instructions stored on the computer-readable storage medium produce a product that includes instruction means for implementing one or more functions specified in one or more blocks of the flow diagram. By way of example, a particular implementation may provide a computer program product comprising a computer-readable storage medium having computer-readable program code or program instructions embodied therein, the computer-readable program code being adapted to be executed to implement one or more functions specified in one or more blocks of the flow diagram. The computer program instructions may also be loaded into a computer or other programmable data processing apparatus to produce a specific machine, such that the instructions executed on the computer or other programmable apparatus provide elements or steps for implementing the functions specified in one or more blocks of the flow diagram, such that a series of operational elements or steps are executed on the computer or other programmable apparatus to produce a computer-implemented process.

[0129] Thus, the blocks of the block diagrams and flow diagrams support combinations of means for performing the specified functions, combinations of elements or steps for performing the specified functions, and program instruction means for performing the specified functions. It will also be understood that each block of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and flow diagrams, can be implemented by a dedicated hardware-based computer system that performs the specified functions, elements, or steps, or a combination of dedicated hardware and computer instructions.

[0130] Unless otherwise specified or understood otherwise within the context in which it is used, conditional language such as "can," "may," "may," and "may," among others, is generally intended to convey that certain features, elements, and / or operations may be included in a particular implementation while not being included in other implementations. Thus, such conditional language is generally not intended to imply that the features, elements, and / or operations are in any way required for one or more implementations, or that one or more implementations necessarily include logic for determining, with or without user input or prompting, whether or not those features, elements, and / or operations are included in or performed in any particular implementation.

[0131] Many modifications and other implementations of the disclosure described herein will be apparent having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. It is therefore to be understood that the disclosure should not be limited to the particular implementations disclosed, and that modifications and other implementations are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0132] The following examples relate to embodiments according to the present disclosure.

[0133] Example 1 is an automated method for landing a probe on a device under test (DUT), the method including the steps of: positioning a conductive probe over the DUT by an automated motion control system; applying an electrical signal between the conductive probe and the DUT by a signal measurement circuit; measuring an electrical response from the applied electrical signal by the signal measurement circuit; calculating, by a processor, an impedance magnitude value and / or a phase angle value based on the measured electrical response value; moving the conductive probe toward the DUT while continuing to calculate, by the automated motion control system, the impedance magnitude value and / or the phase angle value from the measured electrical response; determining, by the processor, that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or the phase angle value; and sending a signal by the processor to the automated motion control system to stop movement of the probe toward the DUT based on a change in the calculated impedance magnitude value and / or the phase angle value. The motion control device can automatically stop the probe based on receiving a signal from the processor indicating that the probe has contacted a surface, where such indication of surface contact is based on the impedance and / or phase determination.

[0134] Example 2 may include the subject matter described in example 1, wherein determining that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or phase angle value includes determining, by the processor, a change in a rate of change of the calculated impedance magnitude value and / or phase angle value.

[0135] Example 3 may include the subject matter of example 1 or 2, wherein the change in the calculated impedance magnitude value and / or phase angle value includes a value, or an average of the values, a change by a predetermined amount from a baseline, or a match / crossing with an absolute value.

[0136] Example 4 may include the subject matter of any of examples 1-3, wherein the change in the calculated impedance magnitude value and / or phase angle value comprises a change in a noise measurement, frequency, or profile from a baseline or from matching / intersecting with an absolute measure, frequency, or profile.

[0137] Example 5 may include the subject matter of any of examples 1-4, wherein the change in the calculated impedance magnitude value and / or phase angle value includes a rate of change that changes by a predetermined amount from a baseline, or a rate of change that meets / intersects an absolute rate of change.

[0138] Example 6 may include the subject matter of any of examples 1-5, further including performing an electrical test on the DUT.

[0139] Example 7 may include the subject matter described in Example 6 and may include determining that electrical testing of the DUT is completed; sending a signal to an operation control device to disconnect the conductive probe from the DUT; and determining, by the processor, that the conductive probe has disconnected from the DUT based on the aforementioned change in the calculated impedance magnitude value and / or phase angle value.

[0140] Example 8 may include the subject matter described in Example 7, and may also include determining a second DUT to test based on the test plan, and sending a signal to an operation control device to position the conductive probe over the second DUT.

[0141] Example 9 may include the subject matter described in Example 8, wherein the step of positioning the conductive probe over the second DUT further includes the steps of identifying coordinates of the second DUT and positioning the conductive probe over the second DUT based on the coordinates of the second DUT.

[0142] Example 10 may include the subject matter described in Example 8, wherein the step of positioning the conductive probe over the second DUT includes the steps of identifying coordinates of the second DUT and positioning the second DUT under the conductive probe based on a transformation of the coordinates of the second DUT.

[0143] Example 11 may include the subject matter of any of Examples 1-10, and may also include determining a type of DUT from the received impedance magnitude values ​​and / or phase angle values ​​based at least in part on comparing the calculated impedance magnitude and phase angle to previous values.

[0144] Example 12 may include the subject matter described in any of Examples 1-11, and may also include the steps of stopping testing of the DUT before testing of the DUT is completed, measuring an impedance magnitude value and / or a phase angle value, determining that the conductive probe has drifted or moved from the DUT, repositioning the conductive probe on the DUT, and completing testing of the DUT.

[0145] Example 13 may include the subject matter described in any of Examples 1-12, and may also include determining, by the processor, that the impedance magnitude value and / or the phase angle value indicate proximity between the conductive probe and the DUT, and signaling an operation control device to increase or decrease a speed of movement of the conductive probe toward the DUT based on the proximity between the conductive probe and the DUT determined from the impedance magnitude value and / or the phase angle value.

[0146] Example 14 may include the subject matter of any of Examples 1-13, and may also include determining, by the processor, that the impedance magnitude value and / or the phase angle value indicate a physical shape of the conductive probe; determining whether the physical shape of the conductive probe is suitable for contacting the DUT based on the impedance magnitude value and / or the phase angle value; and signaling the motion control device to stop and abort the processing if the conductive probe does not have a physical shape for contacting the DUT, or signaling the motion control device to continue moving the probe toward the DUT if the conductive probe has a physical shape for contacting the DUT.

[0147] Example 15 is a system comprising: a nanoprober including an actuator for fixing a conductive probe; a signal measurement circuit electrically coupled to the conductive probe, the signal measurement circuit applying a signal to the conductive probe and receiving a signal from the sample or applying a signal to the sample and receiving a signal from the conductive probe; a motion control system moving the nanoprober actuator based on information received from the signal measurement circuit; and a hardware processor determining that the information from the signal measurement circuit indicates proximity of the conductive probe to a target surface, determining that the information from the signal measurement circuit indicates suitability or quality of the conductive probe, determining that the information from the signal measurement circuit indicates that the conductive probe has landed on the target surface, and signaling the motion control system to stop movement of the nanoprober positioning device based on the indication that the conductive probe has landed on the target surface.

[0148] Example 16 may include the subject matter described in example 15, wherein the operational control system lowers the conductive probe toward the DUT while the signal measurement circuit receives the electrical information and the processor calculates an impedance magnitude and a phase angle between the voltage and current based on the received electrical information.

[0149] Example 17 may include the subject matter described in example 16, wherein the processor determines that the magnitude of the received impedance or the phase angle between the voltage and current values ​​is indicative of a proximity of the tip of the conductive probe to the DUT, and sends a signal to the motion control system to alter a speed of movement of the conductive probe based on the proximity to the DUT.

[0150] Example 18 may include the subject matter described in example 16, wherein the processor determines that the magnitude of the received impedance or the phase angle between the voltage and current values ​​indicates landing an unusable probe tip on the DUT and signals the motion control system to stop moving the conductive probe towards the DUT and abort the landing.

[0151] Example 19 may include the subject matter described in Example 16, wherein the processor determines whether the magnitude of the received impedance or the phase angle between the voltage and current values ​​meets or exceeds a threshold value, or any other change in behavior from a calculated criteria, determines that the conductive probe has contacted the DUT based on the magnitude of the impedance or the phase angle between the voltage and current values ​​meeting or exceeding a threshold value, or any other change in behavior from the calculated criteria, and signals the motion control system to stop moving the conductive probe toward the DUT.

[0152] Example 20 may include the subject matter of any of Examples 15-19, wherein the processor determines what the DUT is based on the stored information, and performs electrical testing of the DUT via the signal measurement circuitry based on what the DUT is.

[0153] Example 21 may include the subject matter described in Example 20, wherein the processor determines that an electrical test of the DUT is completed and signals the motion control device to lift the conductive probe from the DUT or move the DUT away from the conductive probe.

[0154] Example 22 may include the subject matter described in Example 21, and the processor may determine a second DUT to test based on the test plan, identify a position of the second DUT, and move one or both of a sample stage supporting the second DUT and the tip of the conductive probe so that the tip of the conductive probe is above the second DUT.

[0155] Example 23 may include the subject matter described in Example 22, wherein the processor identifies coordinates of a second DUT and, based on the coordinates of the second DUT, signals the motion control system to position the conductive probe over the second DUT or signals the motion control system to position the DUT under an origin of a charged particle beam (CPB) device.

[0156] Example 24 may include the system described in Example 23, wherein the processor identifies coordinates of a second DUT and signals the motion control system to position the conductive probe over the second DUT based on a transformation of the coordinates of the second DUT.

[0157] Example 25 may include the subject matter of any of Examples 15-24, wherein the processor determines the type of DUT based on a comparison of the electrical information calculated from the received impedance magnitude values ​​and / or phase angle between the voltage and current values ​​to past values.

[0158] Example 26 may include the subject matter of any of Examples 15-25, wherein the processor stops the electrical testing of the DUT before the electrical testing of the DUT is completed, determines via the current received via the signal measurement circuitry a value of the impedance magnitude and / or a phase angle between the voltage and the current, determines that the conductive probe has drifted or moved from the DUT, and signals the motion control system to reposition the conductive probe over the DUT to complete the electrical testing of the DUT.

[0159] Example 27 is a system including a nanoprober system that fixes a conductive probe; a motion control system; a signal measurement circuit that applies a signal to the conductive probe and receives a signal from the sample or applies a signal to the sample and receives a signal from the probe; a motion control system that moves a nanoprober positioning device based on information received from the signal measurement circuit; and a hardware processor that positions the conductive probe over a DUT by the motion control system, applies an electrical signal between the conductive probe and the DUT, measures an electrical response from the applied electrical signal, calculates an impedance magnitude value and / or a phase angle value based on the measured electrical response value by the processor, moves the conductive probe toward the DUT while continuing to calculate an impedance magnitude value and / or a phase angle value from the measured electrical response by the motion control device, determines that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or phase angle value, and signals the motion control device by the processor to stop moving the probe toward the DUT based on a change in the calculated impedance magnitude value and / or phase angle value.

[0160] Example 28 may include the subject matter described in example 27, wherein determining that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or phase angle value includes determining, by the processor, a change in a rate of change of the calculated impedance magnitude value and / or phase angle value.

[0161] Example 29 can include the subject matter of example 27 or 28, wherein the change in the calculated impedance magnitude value and / or phase angle value includes a value, or an average of the values, a change by a predetermined amount from a baseline, or a match / crossing with an absolute value.

[0162] Example 30 may include the subject matter of any of examples 27-29, wherein the change in the calculated impedance magnitude value and / or phase angle value comprises a change in a noise measure, frequency, or profile from a baseline or from matching / intersecting with an absolute measure, frequency, or profile.

[0163] Example 31 can include the subject matter of any of examples 27-30, wherein the change in the calculated impedance magnitude value and / or phase angle value includes a rate of change that changes by a predetermined amount from a baseline, or a rate of change that meets / intersects an absolute rate of change.

[0164] Example 32 may include the subject matter of any of Examples 27-31, and may also include performing an electrical test on the DUT.

[0165] Example 33 may include the subject matter described in Example 32, and may also include determining that electrical testing of the DUT is completed, sending a signal to an operation control device to disconnect the conductive probe from the DUT, and determining, by the processor, that the conductive probe has disconnected from the DUT based on the aforementioned change in the calculated impedance magnitude value and / or phase angle value.

[0166] Example 34 may include the subject matter described in Example 33, and may also include determining a second DUT to test based on the test plan, and sending a signal to the operation control device to position the conductive probe over the second DUT.

[0167] Example 35 may include the subject matter described in Example 34, wherein placing the conductive probe over the second DUT includes identifying coordinates of the second DUT and placing the conductive probe over the second DUT based on the coordinates of the second DUT.

[0168] Example 36 may include the subject matter described in Example 34, wherein positioning the conductive probe over the second DUT includes identifying coordinates of the second DUT and positioning the second DUT under the conductive probe based on a transformation of the coordinates of the second DUT.

[0169] Example 37 may include the subject matter of any of Examples 27-36, and may also include determining a type of DUT from the received impedance magnitude values ​​and / or phase angle values ​​based at least in part on comparing the calculated impedance magnitude and phase angle to previous values.

[0170] Example 38 may include the subject matter of any of Examples 27-37, and may also include stopping testing of the DUT before testing of the DUT is completed, measuring an impedance magnitude value and / or a phase angle value, determining that the conductive probe has drifted or moved from the DUT, repositioning the conductive probe to the DUT, and completing testing of the DUT.

[0171] Example 39 may include the subject matter of any of Examples 27-38, and may also include determining, by the processor, that the impedance magnitude value and / or the phase angle value indicate proximity between the conductive probe and the DUT, and sending a signal to an operation control device to increase or decrease a speed of movement of the conductive probe toward the DUT based on the proximity between the conductive probe and the DUT determined from the impedance magnitude value and / or the phase angle value.

[0172] Example 40 may include the subject matter of any of Examples 27-39, and may also include determining, by the processor, that the impedance magnitude value and / or the phase angle value are indicative of a physical shape of the conductive probe, determining whether the physical shape of the conductive probe is suitable for contacting the DUT based on the impedance magnitude value and / or the phase angle value, and signaling the motion control device to stop and abort processing if the conductive probe does not have a physical shape for contacting the DUT, or signaling the motion control device to continue moving the probe toward the DUT if the conductive probe has a physical shape for contacting the DUT. [Explanation of symbols]

[0173] 100, 150 Automatic probe landing system 102 Charged Particle Beam System (CPB System) 104 Vacuum Chamber 106 CPB Imaging Column 108 Electron Detector 110 Sample stage 112, 112a-112d Nanoprober 114, 602, 702 Probes 116 Vacuum Pass-Through 118 Signal Measuring Circuit 120 Computer Systems 122 Motion Control System 124 samples 126 Return Line 154 Mounting ring 202 Rough positioning device 204 Precision Positioning Device 604, 704 chips 606, 706 Source contact, landing target

Claims

1. 1. A method for landing a probe on a device under test (DUT), comprising: using a motion control device to position a conductive probe over the DUT with the motion control device; applying an electrical signal between the conductive probe and the DUT; measuring an electrical response from the applied electrical signal; calculating, by a processor, a value of the impedance magnitude and / or a value of the phase angle between the voltage and the current based on the measured values ​​of the electrical response; moving the conductive probe towards the DUT while continuing to calculate, by the motion control device, impedance magnitude values ​​and / or phase angle values ​​between voltage and current from the measured electrical responses; determining, by the processor, that the conductive probe has contacted the DUT based on a change in the calculated impedance magnitude value and / or phase angle value; sending a signal by the processor to the motion control device to stop movement of the probe towards the DUT based on the change in the calculated impedance magnitude value and / or phase angle value; stopping, by the motion control device, the probe upon receipt of a signal from the processor; Including, The method, wherein the step of determining that the conductive probe has contacted the DUT based on a change in a calculated impedance magnitude value and / or phase angle value includes a step of determining by the processor a change in a rate of change of the calculated impedance magnitude value and / or phase angle value.

2. 2. The method of claim 1, wherein the change in the calculated impedance magnitude value and / or phase angle value comprises a value, or an average of a value, a change by a predetermined amount from a baseline, or a match / crossing with an absolute value.

3. 2. The method of claim 1 , wherein the change in the calculated impedance magnitude value and / or phase angle value comprises a change in a noise frequency or noise profile from a baseline or from matching / intersecting an absolute noise frequency or noise profile.

4. 2. The method of claim 1, wherein the change in the calculated impedance magnitude value and / or phase angle value comprises a rate of change that changes from a reference by a predetermined amount, or a rate of change that meets / crosses an absolute rate of change.

5. The method of claim 1 , further comprising the step of performing an electrical test on the DUT.

6. determining that the electrical testing of the DUT is complete; sending a signal to the motion control device to isolate the conductive probe from the DUT; determining, by a processor, that the conductive probe has become detached from the DUT based on the change in the calculated impedance magnitude value and / or phase angle value; The method of claim 5 further comprising:

7. determining a second DUT to test based on the test plan; sending a signal to the motion control device to position the conductive probe over the second DUT; The method of claim 6 further comprising:

8. The step of positioning the conductive probe over the second DUT comprises: identifying coordinates of the second DUT; positioning the conductive probe over the second DUT based on the coordinates of the second DUT; The method of claim 7, comprising:

9. The step of positioning the conductive probe over the second DUT comprises: identifying coordinates of the second DUT; positioning the second DUT under the conductive probe based on the transformation of the coordinates of the second DUT; The method of claim 7, comprising:

10. determining a type of the DUT based on a comparison of the calculated impedance magnitude and phase angle from the received impedance magnitude and / or phase angle values ​​with past values; The method of claim 1 further comprising:

11. before the electrical testing of the DUT is completed; stopping the electrical testing of the DUT; Measuring an impedance magnitude value and / or a phase angle value; determining that the conductive probe has drifted or moved away from the DUT; repositioning the conductive probe over the DUT; completing the electrical testing of the DUT; The method of claim 5 further comprising:

12. determining, by a processor, that the impedance magnitude value and / or phase angle value are indicative of proximity between the conductive probe and the DUT; sending a signal to the motion control device to increase or decrease a speed of movement of the conductive probe towards the DUT based on the proximity between the conductive probe and the DUT determined from the impedance magnitude value and / or the phase angle value; The method of claim 1 further comprising:

13. determining, by a processor, that the impedance magnitude value and / or phase angle value are indicative of a physical shape of the conductive probe; determining whether the physical configuration of the conductive probe is suitable for contacting the DUT based on the impedance magnitude value and / or phase angle value; if the conductive probe does not have a physical shape for contacting the DUT, sending a signal to the motion control device to stop and abort the method of landing a probe on the DUT; or if the conductive probe has a physical configuration for contacting the DUT, sending a signal to the motion control device to continue moving the probe toward the DUT; The method of claim 1 further comprising:

14. 1. A system comprising: a nanoprober including an actuator for fixing a conductive probe; a signal measurement circuit electrically coupled to the conductive probe, the signal measurement circuit applying a signal to the conductive probe and receiving a signal from a sample, or applying a signal to a sample and receiving a signal from the conductive probe; a motion control system that moves an actuator of the nanoprober based on values ​​of impedance magnitude and / or values ​​of phase angle between voltage and current received from the signal measurement circuit; 1. A hardware processor comprising: determining that a value of the impedance magnitude and / or a value of the phase angle between the voltage and the current from the signal measurement circuit is indicative of a proximity of the conductive probe to a surface of interest; determining that a value of the impedance magnitude and / or a value of the phase angle between the voltage and the current from the signal measurement circuit is indicative of the suitability or quality of the conductive probe; determining that an impedance magnitude value and / or a phase angle value between voltage and current from the signal measurement circuit indicates that the conductive probe has landed on a target surface; sending a signal to the motion control system to stop movement of the nanoprober positioner based on an indication that the conductive probe has contacted the target surface; A hardware processor; Equipped with The system, wherein determining that an impedance magnitude value and / or a phase angle value between voltage and current indicates that the conductive probe has landed on the target surface includes determining by the hardware processor a change in a rate of change of the impedance magnitude value and / or the phase angle value.

15. 15. The system of claim 14, wherein the motion control system lowers the conductive probe toward the surface of interest while the signal measurement circuit receives electrical information and the hardware processor calculates impedance magnitude and phase angle between voltage and current based on the received electrical information.

16. The hardware processor includes: determining that a magnitude of the received impedance or a phase angle between voltage and current values ​​is indicative of a proximity of the tip of the conductive probe to the surface of interest; The system of claim 15 , further comprising: sending a signal to a motion control system to vary a speed of movement of the conductive probe towards the target surface based on the proximity.

17. The hardware processor includes: determining that the magnitude of the impedance or the phase angle between the voltage and current values ​​received is indicative of an unusable probe tip landing on the target surface; 16. The system of claim 15, further comprising: a signal to the motion control system to stop movement of the conductive probe toward the target surface and abort the landing.

18. The hardware processor includes: determining whether the magnitude of the impedance or the phase angle between the received voltage and current values ​​meets or exceeds a threshold; determining that the conductive probe has contacted the surface of interest based on whether the magnitude of the impedance or the phase angle between voltage and current values ​​meets or exceeds the threshold; The system of claim 15 , further comprising: a signal to the motion control system to stop movement of the conductive probe toward the target surface.

19. The hardware processor includes: determining what the target surface is based on the stored information; The system of claim 14 , further comprising: performing electrical testing of the surface of interest via the signal measurement circuitry based on the identity of the surface of interest.

20. The hardware processor includes: determining that the electrical testing of the target surface is complete; 20. The system of claim 19, further comprising: sending a signal to the motion control system to lift the conductive probe off the target surface or move the target surface away from the conductive probe.

21. The hardware processor includes: determining a second DUT to test based on the test plan; Identifying a location of the second DUT; 21. The system of claim 20, further comprising: moving one or both of a sample stage supporting the second DUT and the tip of the conductive probe so that the tip of the conductive probe is above the second DUT.

22. The hardware processor includes: Identifying coordinates of the second DUT; 22. The system of claim 21, further comprising: based on the coordinates of the second DUT, sending a signal to the motion control system to position the conductive probe over the second DUT or sending a signal to the motion control system to position the surface of interest under an origin of a CPB device.

23. The hardware processor includes: Identifying coordinates of the second DUT; 23. The system of claim 22, further comprising: a signal to the motion control system to position the conductive probe over the second DUT based on the transformation of the coordinates of the second DUT.

24. The hardware processor includes: The system of claim 14, further comprising: determining the type of surface of interest based on a comparison of electrical information calculated from received impedance magnitude values ​​and / or phase angles between voltage and current values ​​with historical values.

25. The hardware processor includes: prior to completion of said electrical testing of said target surface; stopping said electrical testing of said target surface; determining an impedance magnitude value and / or a phase angle between voltage and current via the current received via said signal measurement circuit; determining that the conductive probe has drifted or moved away from the surface of interest; sending a signal to the motion control system to reposition the conductive probe over the target surface; 20. The system of claim 19, further comprising: a) completing said electrical testing of said surface of interest;

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