Dynamic response analysis prober device

Abstract

The present invention relates to a prober device that shapes an input waveform of a dynamic electric signal to be input to one of probes, and observes an output waveform of the dynamic electric signal output through a sample, or preferably shapes the input waveform such that the output waveform of the dynamic electric signal output through the sample becomes approximately a pulse shape, when a response analysis of a dynamic signal is performed with respect to a fine-Structured device. With this, the response analysis of a high-speed dynamic signal equal to or greater than a megahertz level can be performed with respect to the fine-Structured device such as a minute transistor configuring an LSI.

Claims

1. A prober device comprising: a sample stage that holds a sample; a plurality of probes that come into contact with predetermined positions of the sample; a sample room in which the sample stage and the plurality of probes are disposed in an inside thereof; a charged particle beam microscope for observing the sample and the plurality of probes; an input waveform forming mechanism that shapes an input waveform of a dynamic electric signal to be input to one of the probes; and an output waveform observing mechanism for observing an output waveform of the dynamic electric signal output through the sample, wherein the input waveform forming mechanism shapes the input waveform such that the output waveform becomes rectangular when the plurality of probes is contacted with the contacts of a normal transistor of the sample, and the output waveform observing mechanism obtains the dynamic response characteristic of another transistor that receives the shaped input waveform of the sample.

2. The prober device according to claim 1, the input waveform forming mechanism is configured to adjust the input waveform such that the output waveform of the dynamic electric signal output through the sample becomes approximately a pulse shape.

3. The prober device according to claim 2, the input waveform forming mechanism is configured to shape the input waveform with at least one of a convex portion at a front part of the input waveform and a concave portion at a rear part of the input waveform.

4. The prober device according to claim 1, further comprising: a database in which the input waveform of the dynamic electric signal is recorded, the input waveform forming mechanism configured to form the input waveform recorded in the database according to a condition of the dynamic electric signal to be input.

5. The prober device according to claim 1, the input waveform forming mechanism configured to automatically form the input waveform based on equivalent circuit simulation of a measurement system.

6. The prober device according to claim 1, further comprising: a first CCD camera disposed above a top surface of the sample to observe the sample from above; and a second CCD camera disposed adjacent to a side surface of the sample to observe the sample from a lateral direction.

7. The prober device according to claim 1, the sample room is divided into a first sample observation region for observation by a scanning electron microscope, a second sample observation region for observation by an optical microscope, and a probe exchange region.

8. The prober device according to claim 7, the sample stage being movable between the first sample observation region, the second sample observation region, and the probe exchange region.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram of a measurement path of a prober device.

(2) FIG. 2A is a diagram illustrating a state where a probe is in contact with a sample.

(3) FIG. 2B is a diagram illustrating the state where the probe is in contact with the sample.

(4) FIG. 3 is a schematic diagram of the prober device for fine-Structured device characteristic evaluation of Example 1.

(5) FIG. 4A is a graph for explaining the influence of a frequency bandwidth on a pulse shape.

(6) FIG. 4B is a graph for explaining the influence of the frequency bandwidth on the pulse shape.

(7) FIG. 4C is a graph for explaining the influence of the frequency bandwidth on the pulse shape.

(8) FIG. 5 is a configuration diagram of a prober device for fine-Structured device characteristic evaluation of Example 2.

(9) FIG. 6 is a schematic diagram of a prober device for fine-Structured device characteristic evaluation of Example 3.

(10) FIG. 7 is a schematic diagram of a prober device for fine-Structured device characteristic evaluation of Example 4.

(11) FIG. 8 is a schematic diagram of a prober device for fine-Structured device characteristic evaluation of Example 5.

DESCRIPTION OF EMBODIMENTS

(12) In Example, disclosed is a prober device including a sample stage that holds a sample, a plurality of probes that come into contact with predetermined positions of the sample, a sample room in which the sample stage and the plurality of probes are disposed in an inside thereof, a charged particle beam microscope for observing the sample and the probe, an input waveform forming mechanism that shapes an input waveform of a dynamic electric signal to be input to one of the probes and an output waveform observing mechanism for observing an output waveform of the dynamic electric signal output through the sample.

(13) In addition, in the Example, it is disclosed that the input waveform is adjusted such that the output waveform of the dynamic electric signal output through the sample becomes approximately a pulse shape. In addition, in the Example, it is disclosed that the input waveform is convex at the front part of a waveform or is concave at the rear part of the waveform.

(14) In addition, in the Example, disclosed is the prober device including a database in which the input waveform of the dynamic electric signal is recorded, and the input waveform forming mechanism forms the input waveform recorded in the database according to a condition of the dynamic electric signal to be input.

(15) In addition, in the Example, disclosed is the prober device in which the input waveform forming mechanism automatically forms the input waveform based on equivalent circuit simulation of a measurement system.

(16) In addition, in the Example, disclosed is the prober device in which the input waveform forming mechanism automatically corrects the output waveform such that the output waveform becomes approximately rectangular based on the output waveform.

(17) Hereinafter, the above and other novel features and effects will be described with reference to the drawings.

Example 1

(18) FIG. 3 is a schematic diagram of the prober device for fine-Structured device characteristic evaluation of the Example.

(19) The prober device in the Example includes a probe 3 for measuring electric characteristics of the sample 4 by being brought into contact with a contact or the like on a sample 4 in a vacuum chamber 7 which can maintain vacuum therein, a SEM column 9 for irradiating the probe 3 and the sample 4 with an electron beam, and a secondary electron detector 10 for detecting secondary electrons generated from the probe 3 and the sample 4 by the irradiation with the electron beam.

(20) In addition, in the prober device, a probe driving mechanism (not shown) for driving the probe 3 and a sample stage 11 for moving a position of the sample 4 are provided.

(21) In a case where the electric characteristics of a transistor are obtained, since it is necessary to bring the probe into contact with each contact of a source, a drain, and a gate, at least three probes 3 are required. When considering the probe 3 to come in contact with a substrate, a preliminary probe for a case where damage occurs in the probe 3, or the like, the number of the probes may be more than three, and, for example, six or more probes may be provided.

(22) Movement of the probe 3 and the sample stage 11 is operated by a measurer using a control terminal (not shown).

(23) The probe 3 is moved to the desired contact, the probe 3 is brought into contact with the contact, a measurement signal is sent from the function generator 1 to an oscilloscope 6 via the probe 3, a voltage required for driving the transistor is applied by a semiconductor parameter analyzer 12, and dynamic response characteristics are obtained such that the electric characteristics of the sample 4 are analyzed and evaluated.

(24) Here, as described above, due to a unique configuration of the prober device, it is difficult to secure a frequency bandwidth to be transmitted. FIG. 4A to FIG. 4C are graphs for explaining the influence of the frequency bandwidth on the pulse shape. When a bandwidth of sufficient transmission frequency is secured, in a case where a pulse wave is transmitted to this system, a clean rectangular wave is maintained and output (FIG. 4A). Meanwhile, in a case where the frequency bandwidth of a transmission signal is small, a rising portion of a rectangle in a pulse waveform to be input deteriorates (FIG. 4B). This is because the pulse waveform is configured with a large number of frequency components, and the rising and falling portions of the rectangle in the pulse waveform correspond to a high-frequency component. That is, in the measurement system with a small transmission bandwidth, this high-frequency component deteriorates, and as a result, the rectangle of the obtained pulse waveform is not maintained in a rising shape as illustrated in FIG. 4B. Meanwhile, in other words, by observing the shape of the rising of this rectangle, characteristics of a measurement object at a higher frequency can be grasped.

(25) In the Example, when measuring dynamic response characteristics in the prober device, the input waveform is shaped such that an output signal waveform becomes rectangular and signal deterioration in a transmission system of the prober device is compensated. By comparing rising of a standard sample in which the rectangle is maintained with rising of an output signal of a comparative sample by using this transmission waveform, it is possible to measure differences in the sample characteristics at a higher frequency.

(26) FIG. 4C is a representative shape of the input waveform of which the waveform is shaped. Transmission deterioration in a portion corresponding to a rising or falling portion where deterioration is expected is corrected as a shape in which a voltage is rapidly raised or lowered to compensate for. In actual measurement, a rising amount and a rise time of the voltage of this shape are determined by the equivalent circuit simulation of the measurement system.

Example 2

(27) In the Example, the failure analysis by the prober device for the fine-Structured device characteristic evaluation will be described. Hereinafter, differences from Example 1 will be mainly described.

(28) FIG. 5 is a configuration diagram of the prober device for the fine-Structured device characteristic evaluation of the Example. The prober device for evaluating the fine-Structured device characteristics includes the probe 3 for measuring the electric characteristics and the sample stage 11 in which the sample 4 of the electronic device or the like can be installed in the vacuum chamber 7.

(29) In addition, the prober device further includes the SEM column 9 for irradiating the probe 3 and the sample 4 with the electron beam, and the secondary electron detector 10 for detecting the secondary electrons generated from the probe 3 and the sample 4 by the irradiation with the electron beam.

(30) A turbo molecular pump 13 and a dry pump 14 for exhausting air in an inside thereof are provided in the vacuum chamber 7. As long as a pump can keep the inside of the vacuum chamber 7 in a vacuum state, a type of the pump is not limited, but the pump which can maintain higher vacuum and not contaminate the vacuum chamber 7 is preferable.

(31) The inside of the vacuum chamber 7 is divided by a sample observation region 15 by the SEM, a sample observation region 16 by an optical microscope, and a probe exchange region 17. By moving the sample stage 11 to these regions, it is possible to perform sample observation by the SEM, the sample observation by the optical microscope, and the exchange of the probe.

(32) The sample stage 11 is basically disposed under the SEM column 9. Furthermore, the probe 3 is disposed between the sample stage 11 and the SEM column 9. The number of the probes 3 is four in the Example. Then, the probe 3 is fixed to a probe driving device (not shown).

(33) The probe 3 is moved to the probe exchange region 17 and the probe 3 is pulled to a probe exchange chamber 18 by using a probe lifting rod 19 such that the probe 3 can be exchanged.

(34) In order to measure the electric characteristics of the sample 4, when the probe 3 is brought into contact with the sample 4, the sample stage 11 is moved to the sample observation region 16 first by the optical microscope. A first CCD camera 20 for observing the sample 4 in the top surface direction and a second CCD camera 21 for observing the sample 4 in the lateral direction are installed at the region. The probe 3 is driven while observing videos of these CCD cameras 20 and 21 such that it is possible to move the probe 3 to a position in which the desired contact is present with an accuracy of approximately 0.1 mm.

(35) In the sample 4, a size of a pattern which is actually desired to be measured is often 100 nm or less in diameter. Therefore, after the above positioning, the sample stage 11 is moved to the sample observation region 15 by the SEM. Then, the probe 3 is operated while observing a SEM image such that the probe 3 is moved to a measurement position more precisely.

(36) Each of the probes 3 is connected to a semiconductor parameter analyzer 12 for measuring the electric characteristics of the electronic device, the function generator 1 for generating a dynamic signal, and the oscilloscope 6 for observing a waveform of a dynamic response signal. The function generator 1 has a function which can arbitrarily create the signal waveform to be generated.

(37) An operation of the device, for example, the movement of the probe 3 and the sample stage 11 is controlled by a graphical user interface (GUI) displayed on a display 22. Regardless of the GUI, control by an operation panel or the like may be used.

(38) Next, a measurement method of the sample 4 will be described.

(39) First, by narrowing down the transistor estimated as defective from failure diagnosis or the like, the sample 4 is polished until a surface of a desired contact of the normal transistor is exposed.

(40) Next, after the sample 4 in which the surface of the contact is exposed is installed on the sample stage 11, the probe 3 is brought into contact with the contact. The probe 3 is brought into contact with the contact of each of the source, the drain, the gate, and the substrate of the transistor.

(41) The probe brought into contact with the drain and the substrate is connected to the semiconductor parameter analyzer 12, the probe brought into contact with the gate is connected to the function generator 1, and the probe brought into contact with the source is connected to the oscilloscope 6.

(42) After each of the probes 3 is brought into contact with each contact, a voltage of 1 V is applied to the drain and a voltage of 0 V is applied to the substrate (grounded). The voltage of 1 V is applied to the gate with the frequency of 100 MHz (pulse width 5 ns) by the function generator 1. A signal from the source at this time is observed with the oscilloscope 6.

(43) If an output response waveform is not the rectangular, the input waveform is shaped. By the waveform shaping, a rise time of 0.7 ns is realized from a pulse shape of 100 MHz. Next, by using the same measurement condition and the input waveform, the dynamic response waveform of the transistor estimated as the defective is observed. As a result, as compared to the normal transistor, in a case where deterioration is observed in the rise time, it can be determined that the transistor is in failure and defective.

Example 3

(44) In the Example, a case where the input waveform is selected from the database will be described. Hereinafter, differences from Examples 1 and 2 will be mainly described.

(45) FIG. 6 is a schematic diagram of the prober device for the fine-Structured device characteristic evaluation of the Example. In the Example, after the probe 3 is brought into contact with each of the contacts 8, the voltage of 1 V is applied to the drain, and the voltage of 0 V is applied to the substrate. When a signal is input to the gate by the function generator 1, the waveform is selected from a database 23 in which waveforms to be used are accumulated based on a frequency to be measured or a type of the sample. With this, an optimum input waveform is applied to the sample and the measurement of the dynamic response signal is performed by the oscilloscope 6.

Example 4

(46) In the Example, a case where the input waveform is determined by using search algorithm will be described. Hereinafter, differences from Examples 1 to 3 will be mainly described.

(47) FIG. 7 is a schematic diagram of the prober device for the fine-Structured device characteristic evaluation of the Example. In the Example, after the probe 3 is brought into contact with each of the contacts 8, the voltage of 1 V is applied to the drain and the voltage of 0 V is applied to the substrate. Before a signal is input to the gate by the function generator 1, an output simulation waveform is derived by using an equivalent circuit simulator of the measurement system in the input waveform. An optimum input waveform is determined by using the search algorithm that repeatedly corrects the simulation waveform to be input such that the waveform becomes rectangular. Performance of a simulation calculation and the search algorithm are performed by a calculation processing unit 24 that instructs the input waveform to the function generator 1. With this, the optimized input waveform is applied to the sample, and the measurement of the dynamic response signal is performed by the oscilloscope 6.

Example 5

(48) In the Example, a case where measurement of the dynamic response signal is performed while correcting the input waveform will be described. Hereinafter, differences from Examples 1 to 4 will be mainly described.

(49) FIG. 8 is a schematic diagram of the prober device for the fine-Structured device characteristic evaluation of the Example. In the Example, after the probe 3 is brought into contact with each of the contacts 8, the voltage of 1 V is applied to the drain and the voltage of 0 V is applied to the substrate. A signal is input to the gate by being automatically repeated by the function generator 1. At this time, the output waveform from the sample 4 is repeatedly obtained, and the measurement of the dynamic response signal is performed while the input waveform is not corrected such that the waveform becomes rectangular. The correction of the input waveform is performed in the calculation processing unit 24 that receives signal information from the oscilloscope 6. By sending a corrected result from the calculation processing unit 24 to the function generator 1, the input waveform to be generated is shaped.

REFERENCE SIGNS LIST

(50) 1 . . . function generator

(51) 2 . . . input cable

(52) 3 . . . probe

(53) 4 . . . sample

(54) 5 . . . output cable

(55) 6 . . . oscilloscope

(56) 7 . . . vacuum chamber

(57) 8 . . . contact

(58) 9 . . . SEM column

(59) 10 . . . secondary electron detector

(60) 11 . . . sample stage

(61) 12 . . . semiconductor parameter analyzer

(62) 13 . . . turbo molecular pump

(63) 14 . . . dry pump

(64) 15 . . . sample observation region by SEM

(65) 16 . . . sample observation region by optical microscope

(66) 17 . . . probe exchange region

(67) 18 . . . probe exchange chamber

(68) 19 . . . probe lifting rod

(69) 20 . . . CCD camera

(70) 21 . . . CCD camera

(71) 22 . . . display

(72) 23 . . . database

(73) 24 . . . calculation processing unit