JPH05251524A - Probe equipment and integrated circuit inspecting equipment - Google Patents

Abstract

PURPOSE:To make it possible to measure the voltage with a high space resolution and a high time resolution by providing the equipment with the specified crystal which induces an electro-optical effect and a connecting device which connects the crystal and the end of a probe at low electric resistance. CONSTITUTION:This equipment has a fine probe 6 whose end part is formed of conductive material and a cantilever 5 whose one end is provided with the probe 6 and the other end fixed on a moving body 2 which can relatively move in the X, Y and Z directions from end to end and top to down of a sample (fine wiring) 9. It also has connecting devices 4, 7 which connect the crystal 1 and the end of the probe 6 at low electric resistance and displacement detecting devices P1, P2 which detect the displacement caused to the cantilever 5 due to the relative approach of the probe 6 to the fine wiring 9. The probe 6 is brought into contact with the detected fine wiring 9 and thereby voltage is applied to the specified crystal 1 through the connecting devices 4, 7 to induce an electro-optical effect on the crystal 1. By this method, the voltage can be measured with a high space resolution and a high time resolution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for inspecting an electric circuit in an operating state, and in particular, it uses a novel probe suitable for performing operation diagnosis and analysis of an integrated circuit including fine wiring such as LSI. The present invention relates to a device configuration for performing voltage measurement by applying voltage to an integrated circuit test. Semiconductor integrated circuit (LSI)
In developing and manufacturing the device, test the device to find out the cause of malfunction (that is, perform failure analysis)
It is indispensable, but with the recent high integration of LSIs and the increase in the number of input / output (I / O) pins, I
It is becoming difficult to perform accurate design verification and failure analysis only by measuring the signal at the / O pin. For this reason,
Internal diagnosis and analysis such as voltage measurement and operation waveform measurement of fine wiring inside the LSI are required. For example, a method in which a probe having a sharp tip is brought into direct contact with a measurement location, a signal detected by the probe is amplified, and measurement is performed with an oscilloscope or the like is the simplest and basic method. However, it is extremely difficult to measure the voltage of the internal wiring and the internal electrode, which are much smaller than the size of the probe, and the measurement accuracy is insufficient, and there is a possibility of a secondary failure such as a short between wirings. Therefore, such a method naturally has its limits. Therefore, it is desired to develop a new measuring method.

[0002]

2. Description of the Related Art As a device suitable for measuring a wiring voltage of a miniaturized pattern, a device utilizing an electron beam or a light beam is known. A device using an electron beam measures the wiring voltage by irradiating a fine wiring (measurement point) in a semiconductor integrated circuit with an electron beam and detecting the amount of secondary electrons emitted from the measurement point. Yes, and utilizes the fact that the amount of detected secondary electrons correlates to the voltage at the measurement point.

On the other hand, as an example of an apparatus utilizing a light beam, a light beam transmitted through the crystal body or a light beam reflected from the crystal body while the light beam is applied to a predetermined crystal body arranged in the vicinity of the measuring point. It is known that the wiring voltage is measured by detecting the polarization amount of.
This is a phenomenon that when an external electric field (that is, a wiring voltage) is applied to a crystal, the refractive index of the crystal changes with anisotropy determined by the crystal structure, that is, an electro-optical effect (electro-op effect).
tic effect) is used. The principle of this electro-optical effect is described in, for example, the literature: Valdmanis JA, Electron.
Lett. 23, 1308-1310, 1987.

In connection with this, when measuring a change in voltage for a short time (for example, 1 ns or less), a pulsed beam is used instead of a continuous beam regardless of whether an electron beam or a light beam is used. A so-called sampling method is used, in which voltage measurement is performed.

[0005]

In an apparatus using an electron beam, it is necessary to narrow down the electron beam in accordance with the size of a fine measurement point, in which case the number of electrons in the beam decreases, and accordingly As a result, the number of secondary electrons also decreases, which causes a problem that the signal-to-noise ratio (S / N ratio) deteriorates. In order to avoid this, it is conceivable to increase the number of shots for one measurement point of the pulsed electron beam, but in this case, there is a problem that the time required for measurement becomes long. The same problem is also raised when the time width of the electron beam pulse is shortened in order to increase the “time resolution” of the measurement. By the way, considering the transit time effect of secondary electrons (blurring of measurement timing caused by slow traveling speed of secondary electrons), it is currently 5p.
About s (picosecond) is the upper limit of the time resolution, and it is extremely difficult in principle to realize a time resolution higher than this.

On the other hand, an apparatus using a light beam has realized an extremely high time resolution exceeding 0.5 ps, and the voltage resolution corresponding to the S / N ratio is also higher than that of the apparatus using an electron beam. However, since the spatial resolution is determined by the wavelength of light, there is a problem that it is extremely difficult to measure the wiring voltage of the ultrafine pattern. By the way, at present, it is possible to measure the voltage for a fine pattern up to about 1 μm (micrometer), but it is very difficult to measure the voltage for a fine pattern below that.

As described above, an apparatus using an electron beam has a good "spatial resolution" but is insufficient in terms of "measurement time" and "temporal resolution". Although excellent in terms of “time” and “temporal resolution”, they were insufficient in terms of “spatial resolution”, and both had opposite advantages and disadvantages. In addition, especially in a voltage measuring device using a light beam that utilizes the electro-optical effect, when probing fine submicron-order wiring compared to the wavelength of the light beam, electrical contact to the wiring may become insufficient. There was a problem that there was.

In view of the above problems in the prior art, a main object of the present invention is to provide a probe device capable of realizing voltage measurement with both improved spatial resolution and temporal resolution. Another object of the present invention is to provide an LSI inspection device capable of stably probing the voltage of the fine wiring without increasing the electrical load on the fine wiring, and thus contributing to the improvement of the accuracy of voltage measurement. To do.

Still another object of the present invention is to provide various improved examples of an apparatus suitable for performing operation diagnosis and analysis of an integrated circuit including fine wiring such as LSI.

[0010]

In order to solve the above-mentioned problems, according to a basic form of the present invention, a fine probe having at least its tip made of a conductive material, and the probe on one end side A cantilever having the other end fixed to a movable body that is attached and movable relative to the sample in each of the XYZ directions; a means for moving the movable body relative to the sample; A predetermined crystal body for inducing the effect, a connecting means for connecting the crystal body and the tip of the probe with low electrical resistance, and the cantilever caused by the relative proximity of the probe to the sample Displacement detecting means for detecting displacement, and the measurement using the electro-optical effect induced in the crystal body when the probe is brought into contact with the measurement point on the sample determined based on the detected displacement Voltage measuring hand to measure the voltage at the point When, the probe device characterized by comprising a are provided.

According to another aspect of the present invention, the probe device described above, monitor means for observing the vicinity of the wiring to be measured inside the integrated circuit, the probe device and monitor means are mounted, and And stage means provided so as to be movable relative to the wiring to be measured,
The stage means has an opening for enabling observation by the monitor means and probing by the probe device, and at least one of a monitor means stage for mounting the monitor means and a probe device stage for mounting the probe device. There is provided an integrated circuit inspection device having:

[0012]

In the basic mode of the present invention, when a fine probe is brought close to, for example, a fine wiring inside an integrated circuit, an atomic force between atoms acts between the probe and the fine wiring, and the force is exerted. The amount of displacement (deflection) depending on the size of the cantilever occurs. Therefore, by measuring the amount of bending, the shape and position of the fine wiring can be detected accurately and accurately. In addition, contact the probe with the detected fine wiring,
The electro-optical effect can be induced in the crystal body by applying the voltage generated in the probe (the voltage of the fine wiring) to the predetermined crystal body through the connecting means. As described above, it is possible to perform measurement with high “spatial resolution” and “temporal resolution”.

The details of other structural features and operations of the present invention will be described using the embodiments described below with reference to the accompanying drawings.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of the probe device of the present invention. In the figure, 1 is a crystal as a predetermined crystal body that induces an electro-optical effect, for example, BSO (Bi ₁₂ Si).
O ₂₀ ) crystal, 2 indicates a transparent probe substrate. The BSO crystal 1 has a transparent electrode (first electrode 3) such as an ITO (In ₂ O ₃ —SnO ₂ ) electrode adhered on the upper surface side and a metal electrode (second electrode) for reflecting light on the lower surface side. Electrode 4) of the probe substrate 2 is adhered, and the second electrode is adhered to one side of the probe substrate 2.

A base end 5a of a cantilever 5 is fixed to one end face 2a of the probe substrate 2, and a minute probe 6 is attached to a free end 5b of the cantilever 5. . This cantilever 5 is made of a material that is extremely flexible and has a light mass (for example, a spring constant of 1 to 1).
It is made of silicon nitride having a mass of about 10 ⁻⁷ to 10 ⁻¹¹ N at 0 N / m, and one surface is mirror-finished. The height of the probe 6 is about 3 μm, the length of the cantilever 5 is about 0.2 mm, and the size of the probe substrate 2 is about 1 mm × 2 mm.

Here, the cantilever 5 and the probe 6 are
Although it is composed of the same components as those included in a known scanning probe microscope, for example, an atomic force microscope (AFM), the difference from the AFM is that at least the tip portion of the probe 6 is present. For example, the cantilever 5 is covered with a metal film and has conductivity.
One surface is covered with a metal thin film of, for example, gold (Au) in order to improve the reflection of the laser beam, which is also conductive, the tip of the probe 6 and the cantilever 5.
The points are electrically connected to each other. Regarding the above AFM, for example, reference is made to G. Binnig, CF Q.
See uate, C. Gerber: Phys. Rev. Lett. 56,930, 1986.

The base end 5a of the cantilever 5 and the second electrode 4
The electrodes 4 together with the wiring 7 and the cantilever 5, the BSO crystal 1 and the probe 6 are connected to each other.
And a connecting means for connecting the tip end portion with low electrical resistance. In such a structure, when the probe 6 attached to the tip of the cantilever 5 is brought close to, for example, the fine wiring (made of a metal material) 9, the atoms forming the fine wiring 9 and the atoms forming the probe 6 are separated from each other. A so-called interatomic force acts between the two, and the cantilever 5 is deformed by a bending amount according to the magnitude of this acting force. For example, when the probe 6 is brought closer to the surface of the fine wiring 9 on the order of nm (nanometer), a repulsive force acts on the probe 6, so that the cantilever 5
Bends slightly in the direction away from the fine wiring 9.

The bending amount of the cantilever 5 is determined by irradiating _one surface (the surface opposite to the probe) of the cantilever 5 with the laser light P ₁ and reflecting angle of the reflected laser light P ₂ (with respect to the normal direction). It can be detected by measuring θ / 2). Therefore, by plotting the change of the reflection angle with respect to the horizontal position of the probe 6 while changing (that is, scanning) the planar relative positional relationship between the probe 6 and the fine wiring 9, It is possible to measure the height (H), width (W) and length (L), and to observe the three-dimensional spatial shape in the Z direction, the X direction and the Y direction, respectively. Further, while adjusting the relative height of the moving body (probe substrate 2 in this case) with respect to the fine wiring (sample) 9, the probe 6 is finely wired so that the reflection angle (θ / 2) becomes constant. 9
The three-dimensional shape of the sample surface can also be observed by scanning with respect to each other and plotting the height of the moving body 2 with respect to the horizontal position of the probe 6.

Moreover, the "spatial resolution" can be given in an extremely minute order corresponding to the size of an atom, and a much higher spatial resolution can be obtained as compared with a conventional device using a light beam. be able to. It should be noted that although it is possible in principle to obtain a spatial resolution on the order of atoms with a normal AFM, considering that recent wiring patterns have become wiring widths on the order of submicrons, as in the present embodiment. Sufficient measurement accuracy can be achieved even with a resolution of several tens of nm.

On the other hand, after detecting the position of the fine wiring 9,
When measuring the voltage of the fine wiring 9, first, the probe 6 is aligned right above the measurement point of the fine wiring 9, and then the probe substrate 2 is moved downward together with the BSO crystal 1 (or On the contrary, the sample 9 side is moved upward and the probe 6 and the fine wiring 9 are brought into contact with each other. The voltage at the measurement point of the fine wiring 9 is the probe 6, the cantilever 5, and the wiring 7.
Through the second electrode 4 and is applied to one surface of the BSO crystal 1. The potential of the first electrode 3 (for example, the ground potential or a predetermined bias potential) is applied to the other surface of the BSO crystal 1, whereby B
The SO crystal 1 changes its refractive index under the influence of an electric field having a magnitude corresponding to the potential difference between both surfaces (electro-optical effect). Therefore, by irradiating the BSO crystal 1 with the laser beam P ₃ given a predetermined polarization and measuring the polarization change of the reflected laser beam P ₄ , the magnitude of the voltage at the measurement point of the fine wiring 9 can be detected. You can For example, as shown in the figure, a circularly polarized laser beam P ₃ having a minor axis D _S3 and a major axis D _L3 equal to each other.
When the laser beam P _{4 which} is changed into an ellipse according to the magnitude of the measured voltage is observed, the minor axis D _{S4 of the} ellipse is irradiated.
And the major axis D _L4 , the magnitude of the measured voltage can be known.

FIG. 2 shows the overall system configuration including the apparatus shown in FIG. In the figure, the device of FIG. 1, that is, the BSO crystal 1, is attached to the upper part of a support 11 fixed to a base 10.
A probe including a probe substrate 2, a cantilever 5 and a probe 6 is attached. An arbitrary sample (for example, a semiconductor integrated circuit chip) 12 including fine wiring is arranged below the probe 6, and the sample 12 is finely held in a three-dimensional direction by an XYZ stage 13 using, for example, a piezo actuator. And stage 1
3 is held by the XYZ stage 14 so that it can be moved roughly.
The coarse movement stage 14 is fixed to the base 10.
The sample 12 is capable of coarse movement and fine movement in each of X, Y, and Z directions including the bending deformation direction (Z direction) of the cantilever 5 due to the atomic force, and these movements are performed between the probe and the probe. Is a relative movement of. Therefore, the probe substrate 2 which is one of the constituent elements of the probe and which fixes the base end 5a of the cantilever 5 has a function as a "moving body" described in the gist of the invention. The moving method is not limited to this example, and the sample 12 may be fixed and the substrate 2 side may be moved, or both may be relatively movable.

The laser light P ₁ generated by the first laser light source 15 is applied to one surface of the cantilever 5, and the laser light P ₂ reflected from the cantilever 5 has a reflection angle at a position detection light receiver (for example, PSD: Position Sensitive Det
16), the wiring detection / contact control unit 17 determines whether the surface area of the sample 12 is 3 based on the measurement result.
Dimensional information (line profile) is reproduced. The wiring detection / contact control unit 17 operates under the control of the system control unit 18 that controls the entire LSI inspection apparatus.

The laser light P ₃ generated by the second laser light source 19 is given a predetermined polarization through the polarizer 20 and the quarter-wave plate 21 (see FIG. 3A), and passes through the beam splitter 22. The BSO crystal 1 is irradiated (see FIG. 3B). Laser light P ₄ reflected from the BSO crystal 1 (see FIG. 3
(See (c)) passes through the beam splitter 22, and is further branched into two directions through the polarization beam splitter 23, and is guided to the photodetectors 24a and 24b, respectively. Each light receiver 24
The outputs of a and 24b are input to the voltage measurement control unit 26 through the differential amplifier 25. The voltage measurement control unit 26 receives, via the system control unit 18, information regarding the position of the measurement wiring detected by the wiring detection / contact control unit 17. The polarization beam splitter 23 cooperates with the polarizer 20 to form a Nicol prism, and has a function of selectively passing predetermined polarized light. In the configuration of FIG. 2, one of the laser beams split by the polarization beam splitter 23 corresponds to the light transmitted through the parallel Nicol and the other passes through the transmissive Nicol. These relationships are shown in FIGS. 3 (d) and 3 (e). In addition, in FIG. 4A to FIG.
Examples of other polarization states corresponding to (e) are shown.

The amount of light detected by the photodetectors 24a and 24b is the magnitude of the electric field of the BSO crystal 1, that is, the sample 12
In response to the magnitude of the voltage at any of the above measurement points, it decreases in the case of parallel Nicols and increases in the case of crossed Nicols. Therefore, the output of each photoreceiver 24a, 24b or the output of the photoreceiver By taking out from the voltage measurement control unit 26 in association with the position information of the measurement point, it is possible to obtain the voltage measurement result with improved “time resolution”. The material of the electro-optical crystal 1, the form of voltage application to the crystal, the optical paths and polarization states of the laser beams P ₃ and P ₄ for voltage measurement, and the number and arrangement of optical elements / detectors for polarization state analysis. It goes without saying that the above is not limited to this example.

In FIG. 2, 27 is a sample drive circuit for supplying a drive signal for operating the LSI chip 12 as a sample, 28 is a voltage measurement result from the voltage measurement control unit 26 and output from the sample drive circuit 27. A timing circuit for supplying a timing signal for optical sampling to the laser light source 19 in response to a trigger signal generated by the laser beam. A variable power supply for applying is shown.

FIG. 5 shows the configuration of another embodiment of the probe device of the present invention. The present embodiment is characterized in that the voltage measuring means (optical sampling system including the laser beams P ₃ and P ₄ ) is replaced with the “reflective type” in FIG. 1 and is “transmissive type”. A transparent electrode 4a having a light transmitting property is provided in place of the electrode 4, and the probe substrate 2 is also transparent.
The other structure and its operation are the same as those of the embodiment shown in FIG. 1, and the description thereof will be omitted.

Next, a voltage measuring method using the apparatus of FIG. 2 will be described with reference to the flowchart of FIG.
First, in step 30, the sample 12 is mounted on the fine movement stage 13, and then in step 31, the coarse movement stage 14 is moved in the horizontal XY directions to move the position of the sample 12.
The movement control at this time is performed, for example, by using an optical microscope so that the probe tip 6 of the probe is located above the rough target area where the measurement target portion (for example, fine wiring) is present, as described later. Be seen.

When the probe 6 reaches the sky above the area, in step 32, an uneven image of the surface of the sample 12, that is, a line profile is observed. In this observation, the probe 6 is lowered to the edge of the surface of the sample 12 (actually, the sample 12 is raised in the Z direction by the fine movement stage 13), and the stage 13 moves the sample 12 with respect to the probe 6 in XY direction. It is performed while scanning in the horizontal direction. As a result, the magnitude of the atomic force acting between the probe 6 and the sample 12 is measured from the amount of bending generated in the cantilever 5, or from the distance between the probe substrate 2 and the sample 12 that keeps the amount of bending constant. ..

In the next step 33, it is determined whether or not a wiring as a measurement target is found in the observation field of view (YES) (NO).
Is determined. If the determination result is NO, the process proceeds to step 34, the sample 12 is slightly moved by the stage 13, and then the process returns to step 32. If the wiring to be measured is found in step 33 (YES), step 3
In step 5, the stage 6 is slightly moved so that the positions of the probe 6 and the measurement target portion of the sample 12 coincide with each other. In the next step 36, the sample 12 is raised to bring the measurement target portion into contact with the probe 6. Next, in step 37, the laser light P ₄ reflected from the BSO crystal 1 of the probe is passed through the beam splitters 22 and 23 to the photodetectors 24a and 24b.
And the change in the refractive index of the BSO crystal 1, that is, the voltage at the measurement target site is measured based on the output. Then
Whether or not there is another measurement target in step 38 (YES) (N
If the determination result is YES, that is, if there is no other measurement target, this flow is “end”. If NO, that is, if there is another measurement target, the process returns to step 31. The above process is repeated.

As described above, according to the probe device of the present embodiment, when the probe 6 is brought close to the fine wiring to be measured, an atomic force acts between the probe 6 and the fine wiring, and the force Since the cantilever 5 is flexed in an amount corresponding to the size, the position of the fine wiring can be accurately and accurately detected by measuring the amount of the flexure, and the fine tip of the probe 6 can be detected in the fine wiring. Since the voltage measurement is performed by bringing them into contact with each other, the “spatial resolution” of the voltage measurement can be improved. Also,
The probe 6 is brought into contact with the detected fine wiring, and the voltage generated at the probe 6 is applied to the electro-optical crystal 1 through the connecting means (the cantilever 5, the wiring 7 and the electrode 4), so that the crystal 1 is applied to the crystal 1. Can induce electro-optic effect,
The "time resolution" of voltage measurement can be improved.

The force acting between the fine probe 6 and the fine wiring is not limited to the above atomic force. For example, electrostatic or magnetic force, or van der Waa
ls) May be power. 7 to 11 show modifications of the probe device shown in FIG. In the modification shown in FIG. 7, 40
Indicates a transparent plate disposed on one side of the cantilever 5 (reflecting surface of displacement measuring laser beam) side at a predetermined interval,
The transparent plate 40 functions as a restricting unit that restricts the amount of bending of the cantilever 5 to a predetermined amount or less. For example, FIG.
As shown in FIG. 7, when searching for a wiring in which the cantilever 5 and the transparent plate 40 are not in contact with each other, flexural deformation of the cantilever 5 is allowed smoothly, and the wiring voltage in which the cantilever 5 and the transparent plate 40 are in contact as shown in FIG. At the time of measurement, flexural deformation of the cantilever 5 is prohibited.

According to this structure, since the flexural deformation at the time of measuring the wiring voltage can be restricted to a predetermined amount or less, it is inconvenient when the spring constant of the cantilever 5 is made as small as possible, that is, the pushing force between the probe 6 and the measurement wiring. The advantage that the contact resistance can be prevented from increasing due to insufficient pressure and that the measurement accuracy of a minute voltage can be improved is obtained. In the configuration of FIG. 7, the case where the transparent plate is provided separately from the probe has been described, but the disposition form of the transparent plate is not limited to this. For example,
As in the modification shown in FIG. 8, the transparent plate 50 may be formed integrally with the probe substrate 2. In this case, since the cantilever 5 and the transparent plate 50 are in contact with each other as shown in FIG. 8B when the wiring voltage is measured, it is possible to restrict further bending deformation of the cantilever 5 as in the case of FIG. 7. FIG. 9 shows the specific configuration thereof, and in this example, a part of the probe substrate 2 is extended to form the transparent plate 50. It should be noted that a separately manufactured transparent plate may be attached to the probe substrate 2.

The regulating means (transparent plates 40, 50) is
Alternatively, the cantilever 5 may be elastically supported by the probe substrate 2 so as to be finely movable along the bending direction of the cantilever 5. Figure 1
In the modified example shown in 0, 60 is another cantilever (hereinafter, this cantilever is referred to as an auxiliary cantilever, which is provided on one side of the cantilever 5 (reflection surface of the displacement measuring laser beam) side with a predetermined interval. The cantilever 5 is referred to as a main cantilever). The sub cantilever 60 functions as a means for changing the spring constant of the entire cantilever, and is formed of a transparent material having a predetermined spring constant. When the main cantilever 5 is flexed and deformed by a predetermined amount or more, both cantilevers 5 and 60 contact each other (see FIG. 7B).

According to this structure, the flexural deformation of the main cantilever 5 at the time of measuring the wiring voltage can be elastically restricted by the total spring constant of the main cantilever 5 and the sub cantilever 60. Also, by adjusting the spring constant of the sub-cantilever 60, the elastic force for regulation can be freely changed. Therefore, it is possible to avoid an excessive contact force between the probe 6 and the measurement wiring at the time of measuring the wiring voltage, prevent damage to the measurement wiring, and prevent damage to the probe such as damage to the main cantilever 5. FIG. 11 shows a specific configuration thereof, and in this example, the main cantilever 5 and the sub cantilever 60 are attached to the side surface of the probe substrate 2.

In the example of FIG. 10, the sub-cantilever 6
Although 0 has a configuration of only one sheet, a plurality of sheets may be provided according to the measurement conditions. FIG. 12 shows the configuration of an embodiment of the LSI inspection apparatus of the present invention.

In the figure, reference numeral 100 is a scanning probe for probing the wiring of the LSI (for example, it corresponds to the portion excluding the optical system for voltage measurement and cantilever displacement measurement in FIG. 1), and 102 is for voltage measurement. The optical sampling means 104, the probe head (scanning probe 100 and the optical sampling means 102) are mounted, and the probe head stage is arranged so as to be finely movable in the XY horizontal direction. 106 is the surface of the sample (LSI). An optical microscope for observation, 108 is a CCD camera for converting an image observed by the optical microscope 106 into an image signal, and 110 is for the optical microscope mounted with the optical microscope 106 and arranged to be finely movable in the X direction. Stage, 11
Reference numeral 2 designates a first stage which is mounted with a probe head stage 104 and optical microscope stage 110, and is arranged so as to be capable of coarse movement in the XY horizontal direction, 114 is a vibration isolation table on which the first stage 112 is mounted, and , 116 are L provided to penetrate the first stage 112 and the vibration isolation table 114.
The opening for SI observation and probing is shown.

In this configuration, the wiring to be measured is observed by the optical microscope 106 through the opening 116, the scanning probe 100 is brought close to the wiring to be measured, the line profile is acquired, and the probe 100 is connected to the wiring to be measured. To position. The wiring voltage is guided to the electro-optic (EO) crystal by the probe 100 to induce the electro-optic effect. In this case, by setting the scanning probe to a length of 200 to 300 μm or less, voltage measurement can be performed without applying an electrical load to the fine wiring.

FIG. 13 shows a state of probing the wiring. FIG. 13A shows a wiring pattern in the peripheral portion of the LSI chip 120. In this example, the measurement wiring 122 is located between the adjacent bonding wires 124. Therefore, as shown in FIG.
Depending on the approaching direction, the probe and the bonding wire 124 interfere with each other, which is inconvenient. In the case of such a measurement pattern, it is necessary to change the approach direction as shown in FIG. 13C, that is, perform probing so that interference does not occur.

FIG. 14 shows an example of a structure capable of such probing. In this example, Z is mounted on the first stage 112 movable in the XY horizontal directions with respect to the vibration isolation table 114.
A second stage (rotary stage) 118 that is rotatable about the directional axis is mounted, and the probe head stage 104 and the optical microscope stage 110 are mounted on the rotary stage 118. As a result, it becomes possible to probe the wiring around the LSI chip where the placement of the scanning probe is restricted by the bonding wire as described above.

FIG. 15 shows another structural example capable of the above probing. In this example, a rotation stage 118a that is rotatable about the Z-direction axis is mounted on the vibration isolation table 114a, and a stage 130 that can be finely moved in the three XYZ directions and on which the LSI chip 120 is mounted is mounted. It is equipped with. As a result, the bonding and
LSI in which the placement of the scanning probe is restricted by the wire
There is an advantage that the wiring around the chip can be probed and the entire stage can be downsized by the absence of the first stage 112 as shown in FIG.

FIG. 16 shows the overall structure of the LSI inspection device 200 including the gantry 140. Inspection device 2
Since 00 does not like vibration, it is necessary to mount it on the pedestal 140 via a vibration isolation means such as an air damper 142.
Further, since the LSI chip is driven by the LSI tester, the test head 150 of the LSI tester is mounted on the vibration isolation table 11
It is necessary to have a structure that can be placed under

At this time, the test head 150 and the inspection device 2
The coupling of 00 requires measures for preventing the tilt of the stages 112 and 118 and eliminating the vibration of the test head 150. FIG. 17 schematically shows how the vibration isolation table 114 tilts due to the rotation of the rotary stage 118. If the center of gravity of the entire apparatus moves due to the rotation of the rotary stage 118 and the height correction action of the air damper 142 cannot be followed up, the stage 118 tilts. In this case, even if the optical axis of the optical microscope 106 is arranged so as to coincide with the central axis of rotation, “escape” of the visual field occurs. In order to prevent this, it is necessary to dispose the center of gravity of the inspection device on the rotary stage 118 as close to the rotation axis as possible. For example, if a counter balance (not shown) is arranged outside the rotary stage 118, it is possible to suppress the stage weight and correct the balance.

Further, in an inspection apparatus having a laser processing apparatus (not shown) for removing the insulating film on the surface of the LSI chip or inside to expose the wiring to be measured, the position of the center of gravity of the laser processing apparatus is the rotation axis of the stage. It is effective to arrange the laser processing device and the sampling optical system so that the laser processing device and the sampling optical system have a substantially symmetrical positional relationship with respect to the center of gravity of the sampling optical system, and the weights of the laser processing device and the sampling optical system are almost equal. is there.

The main cause of the relative vibration between the test head and the vibration isolation table is the rotation of the cooling fan inside the test head. This relative vibration has an amplitude of several tens of μm, and the vibration of the test head and the inspection device including the pedestal vibrates independently due to the floor vibration. Therefore, even if the vibration is fixed to a solid floor, the vibration with an amplitude of 1 μm or more should be avoided. Is not easy. The LSI is generally arranged at the center of a DUT (Device Under Test) board (for example, the DUT board 152 in FIG. 18) on the test head.
Since the test head and the vibration isolation table are placed close to each other, if the test head has a sufficiently high rigidity, grasp the test head with some clamping means to suppress the relative vibration between the test head and the inspection device. can do.

For example, as shown in FIG. 18, the test head 150 is provided with a guide pin 154, and the guide pin 154 is fitted into a corresponding guide hole 156 provided in the vibration isolation table 114. The relative position of the platform 114 can be determined. Further, as shown in FIG. 19, the clamp 160 driven by the actuator 158 grasps the test head 150 to form a mechanically integrated structure, whereby relative vibration can be eliminated.

When the natural vibration of the DUT board 152 poses a problem, the LSI package 120 is directly grasped by the clamp 164 driven by the actuator 162, as shown in FIGS. ,
By configuring the LSI package 120 to be mechanically installed on the vibration isolation table 114, the relative vibration can be almost completely removed. In this example, it is grasped that the side surface of the LSI package is sandwiched, but
The I package can also be fixed by vacuum suction of the flat surface of the package on the vibration isolation table.

Further, when deterioration of the band of the signal supplied to the LSI is allowed, for example, as shown in FIG.
The SI chip 120 and the socket 166 on which the SI chip 120 is mounted are fixed to the vibration isolation table 114 using, for example, screws 168, and the DU
By being connected to the T board 152 by the flexible wiring 170, it is possible to prevent the influence of vibration.

When constructing an LSI inspection device, an optical microscope and a probe head (scanning probe and optical sampling means) for roughly moving the field of view while observing the LSI.
Must be arranged so that they do not interfere with each other.
Further, in order to secure the scanning speed of the scanning probe, special consideration is required to reduce the weight of the scanning probe portion.

First, regarding the prevention of interference, there is a method of selectively using either an optical microscope or a probe head,
A method is considered in which the structure has essentially no interference. Figure 2
In the configuration example shown in FIG. 2, the objective lens 107 of the optical microscope is used by using the rotation holder 180 attached to the optical microscope 106.
Stage 10 for probe head
The probe head is retracted by the movement of 4. When the focus of the optical microscope 106 is short, since that would require close the optical microscope 106 to the sample (LSI chip 120), as shown in FIG. 6 (a), the voltage measurement laser beam P _3, P ₄ and the laser beams P ₁ and P ₂ for displacement measurement interfere with the optical microscope 106. Therefore, the optical microscope 106
When the LSI is not observed, that is, when the voltage is measured, the objective lens 107 is retracted to a position where it does not interfere with the probe head, as shown in FIG. .

Also, as shown in FIG. 23, interference can be similarly avoided by constructing the optical microscope 106 so that it can be mechanically moved upward in the Z-axis during voltage measurement. Further, as shown in FIG. 12, by moving the optical microscope 106 and the probe heads 100 and 102 together,
It is also possible to avoid interference. When an optical microscope with a long working distance and high resolution can be used, the EO sampling optical system (voltage measuring system) near the scanning probe is made thinner than the focal length.
It is possible to perform so-called "in-situ observation" in which the scanning probe is positioned while observing the LSI with an optical microscope.

FIG. 24 shows a structure of the probe scanning system (a) in the apparatus of FIG. 12 and a structure of a normal AFM scanning system (b).
It is shown schematically in comparison with. In the figure, 100 is a scanning probe, 101 is an AFM cantilever, 120 and 120a are samples, 184 is a vibration isolation table, 1
86 and 186a are bases, 188 is a stage movable in the XY directions, 190 and 190a are stages movable in the Z direction, 192 is a laser optical system for displacement measurement, and 194 and 1
94a is a base, and 196 and 196a are position detection optical receivers (P
SD) is shown. The difference between (a) and (b) is that the sample 120 is fixed and the probe scanning system is moved, or the AFM scanning system is fixed and the sample 120 is fixed.
This is due to the difference in moving a. In a normal AFM scanning system, the observation sample 120a is extremely small, so that the sample side can be scanned. Therefore, the AFM portion including the cantilever of the AFM, the laser optical system, the PSD, etc. can be fixed to the highly rigid stage. On the other hand, in the apparatus according to the present embodiment, the LSI (sample) 120 is mechanically installed on the vibration isolation table 184, so that it is necessary to move the entire probe scanning system. Therefore, it is necessary to consider the weight reduction for securing the rigidity and the scanning speed of the portion of the probe scanning system.

FIG. 25 shows some means for reducing the weight of parts of the probe scanning system. In the figure, the hatched portion is a portion that requires scanning. Since the EO sampling crystal is integrated with or placed close to the scanning probe 100, the scanning probe 100
The relative positional relationship between the sampling optical system 102 and the sampling optical system 102 needs to be kept substantially constant. In this case, in order to suppress variations in voltage measurement characteristics due to changes in laser irradiation points on the EO crystal, the position error needs to be kept at 10 μm or less.

FIG. 25A shows a configuration in which the scanning probe 100 and the sampling optical system 102 are mounted on a probe head stage 104 and the entire stage is subjected to AFM scanning. The problem is that the stage weight becomes heavy and the scanning speed decreases, and there are a coarse movement mechanism for moving the stage in units of several centimeters and a fine movement mechanism for AFM scanning (scanning a range of several μm with a resolution of several tens nm). It is necessary and unrealistic.

A more realistic arrangement is shown in FIG.
As shown in, there is a method in which the probe AFM stage 104a and the sampling optical system stage 104b are separately configured, mounted on the stage 112, and moved in synchronization with each other. It is easy to move the stage synchronously due to an error of about 10 μm. Further, since the AFM stage 104a is lightened, the scanning speed can be improved.

FIG. 25C shows a structure in which the AFM stage 104a is mounted on the probe head stage 104. Since the scanning range of the scanning probe 100 is from several μm to several tens of μm, the probe head stage 10
The movement accuracy of 4 is about 2 μm. For example, in FIG.
6, a configuration in which the AFM stage 210 shown in FIG. 27 is held by a probe head stage 220 as shown in FIG. 28 can be considered. In this case, the probe head stage 2
A configuration is suitable in which 20 performs coarse movement adjustment, and although not shown, the AFM stage 210 performs fine movement adjustment by, for example, a piezo actuator.

In FIG. 26, 212 is a laser light source for measuring cantilever displacement, and 214 is a laser light source 21.
A mirror 216 for directing the laser light from the laser beam 2 to the cantilever of the scanning probe 100a is a mirror for directing the laser light reflected from the cantilever to the light receiving system (lens 217 and PSD 218). 27 shows the structure of the scanning probe 100a provided at the tip of the AFM stage 210 of FIG. 26, and the probe basically has the same configuration as the probe device of FIG. . Further, FIG. 29 shows AA ′ of FIG.
1 schematically shows a cross-sectional structure along a line.

In order to reduce the size and weight of the AFM stage, it is effective to reduce the displacement detecting means in the AFM optical system. For example, as shown in FIG. 30, a means for measuring the displacement of the probe 6 of the scanning probe 100b in the Z direction with a scanning tunneling microscope (STM) probe 230 is provided, or as shown in FIGS. 26, 29 and 31. As described above, by bending the optical path of the cantilever displacement measuring laser beam, the height and size of the AFM stage can be suppressed,
It is effective for downsizing. In FIG. 30, 232 is a piezoelectric thin film for enabling the STM probe 230 to perform fine scanning in the Z direction, 234 is an insulating film, and 236 is a bias electrode. In addition, in FIG. 31, 210a, 21
0b is an AFM stage, 212a and 212b are laser light sources, 213a, 213b, 217a and 217b are lenses, 214a, 214b, 216a and 216b are mirrors, and 218a and 218b are PSDs.

The diameter of the portion of the scanning probe that contacts the wiring is, for example, 0.1 μm, which is very weak mechanically. 32 and 33 show a configuration example of a probe attaching / detaching mechanism. In the configuration illustrated in FIG. 32, the EO crystal 24
The transparent electrodes 244 and 248 are adhered to the transparent electrodes 244 and 248, respectively.
The transparent electrode 248 is switched and connected to the power source 252 of the holding voltage V ₁ through 50, and the transparent electrode 248 is the power source 254 of the bias voltage V ₂ .
It is connected to the. In this configuration, the switch 250
When switching to the ground (0V) side, EO crystal 246
Since a bias voltage V ₂ is applied to both ends of the probe 100c, the probe 100c is moved to the EO crystal 242 as shown in FIG.
Is released (released state). On the other hand, when the switch 250 is switched to the power supply 252 side, the holding voltage V ₁ is applied to the transparent electrode 244 of the EO crystal 242.
The crystals 242 are electrostatically adsorbed (holding state). In this configuration, the upper surface of the probe 100c serves as a reflection surface for sampling light. Since the influence of the holding voltage V ₁ is canceled by the round trip of the optical path, it does not affect the measurement result.

In the structure illustrated in FIG. 33, the diaphragm 260 holds the EO crystal 262, and the diaphragm 260 holds the EO crystal 262.
The upper lead portion 268 that expands and contracts with the piezoelectric thin film 266 provided on the
And the lower lead portion 270 allows the scanning probe 10
The base 272 holding 0c is held.
262 is a transparent electrode for transmitting the sampling laser light. According to this configuration, the EO crystal 262
Since the holding mechanism (base 272) of the probe 100c is completely separated, there is an advantage that the crystal is protected.

The EO crystal including the probe attaching / detaching mechanism shown in FIGS. 32 and 33 can be mounted on a base by mounting it on a lever as shown in FIG. 27, for example. Since the lever has a size of the order of several mm, it is produced by electric discharge machining. The lever and the base may be held with an adhesive such as gold paste. The EO crystal and the lever may be connected with a transparent adhesive. The correction of the surface of the EO crystal with respect to the EO optical system is performed by utilizing the bending of the lever portion due to the piezoelectric thin film. Further, the scanning of the scanning probe may be carried out by attaching the base to a piezo element or the like and performing triaxial scanning.

FIG. 34 schematically shows a holding mechanism for the spare probe. In this configuration, each spare probe 280
In contrast, each probe electrostatic attraction electrode 282 is provided. To attach or detach the probe, release the electrode currently attached to the tip of the lever, remove it with, for example, vacuum tweezers, then move to the position of the spare probe with the voltage for holding the probe still applied, and release the spare probe. As a result, the spare probe is electrostatically adsorbed to the EO crystal.

In addition to the method of dealing with the destruction of the probe by replacement as described above, for example, the contact pressure of the probe is positively controlled according to the material of the probe point, and the minimum value required for measuring the probe pressure is set. It is also possible to delay the destruction of the probe by setting to. For example, in FIG.
As shown in, L such as layout information (mask diagram)
SI design database 302, memory system 304 for storing alignment information for calculating stage coordinates for displaying a mask pattern coordinate system (CAD coordinates) and a wiring pattern designated by CAD coordinates on a microscope image,
A means (for example, a mouse) 306 for externally designating a measurement point, a means (for example, CRT) 308 for visually displaying a mask diagram, and operably connected to the respective components 302 to 308, and , Control device 3 for controlling the stage controller 312 in the LSI inspection device 310
00, it is possible to move the stage to a specified location on the design database and display design information such as a mask diagram of the portion displayed in the microscope image, allowing quick and rough movement to the measurement point. In addition, it is possible to read the material information of the measurement point from the design database and determine the contact pressure of the scanning probe.

Further, as shown in FIG. 36, the deviation between the data of the optical microscope image supplied through the image input means 314 in the LSI inspection device 310a and the data of the mask diagram supplied through the control device 300a. By including the alignment means 320 for correcting the position of the probe, it is possible to correct the position coordinates of the probe to be supplied to the probe position control means 316 and perform automatic probing together with the contact pressure information.

FIG. 37 shows a flowchart of the alignment correction process performed by the apparatus shown in FIG. First, in step 330, the measurement point is designated by the input means 306,
At the next step 331, the control device 300a reads the mask diagram information from the design database 302 and sends the mask diagram data to the alignment means 320. In step 332, the control device 300a notifies the stage controller 312 of the stage coordinates. Next step 3
In 33, the image input unit 314 inputs the optical microscope image and transfers the data to the alignment unit 320.
Next, in step 334, the alignment means 320 performs pattern matching between the data of the optical microscope image and the data of the mask diagram, and in the next step 335, the probe coordinates are calculated and the probe coordinate data is supplied to the probe position control means 316. To do. The above steps are processes related to coarse movement.

Next, at step 336, the image input means 3
14 inputs an AFM image of a predetermined area of about several μm square,
Further, in step 337, the control device 300a reads the mask diagram information of the corresponding region from the design database 302 and sends the data to the alignment means 320. In step 338, pattern matching is performed between the AFM image data and the mask diagram data, in the next step 339 the probe coordinates are calculated and the data is supplied to the probe position control means 316, and in step 340 the probe coordinate data is calculated. Based on the above, the probe is moved. The above steps are processes related to fine movement.

FIG. 38 shows a flow chart of the probe contact pressure determination processing performed by the apparatus of FIG. First, in step 350, a measurement point is designated by the input means 306, and in the next step 351, the control device 300a reads out information regarding the material of the measurement wiring from the design database 302. In step 352, it is determined whether the contact pressure of the material is defined (YES) or not (NO). If the determination result is YES, the process proceeds to step 353, and after setting the probe contact pressure, The flow is "end".

If the determination result in step 352 is NO, the contact pressure is increased by a predetermined amount in step 354.
Further, in step 355, the DC drift of the measured voltage is evaluated. Next, in step 356, it is determined whether or not the DC drift is less than or equal to the reference value (YES) (NO), and if the determination result is NO, the process returns to step 354, and gradually the DC drift no longer occurs. Increase the contact pressure. If the determination result in step 356 is YES, the process proceeds to step 357, the probe contact pressure is newly registered, and thereafter, the flow becomes “end”.

Next, the specific arrangement and structure of the LSI inspection apparatus of the present invention will be described with reference to FIGS. In the above-described inspection apparatus using the light beam, the pressing force of the fine probe is controlled with high accuracy to bring it into contact with the measurement wiring, thereby pulling out the wiring voltage to the voltage sensor unit by the light beam without breaking the wiring. It is possible to improve the "spatial resolution", which was insufficient for the diagnosis of future VLSI having a wiring width of 0.3 μm or less by using only the light beam. However, in the past, we have pursued extremely high spatial resolution of several angstroms.
In FM, the observation sample is almost plate-shaped or small, and even in the semiconductor industry field, even plate-shaped wafers can be observed relatively easily.
An LSI driven by an SI tester or the like, and a packaged LSI must be used as a sample.
A conventional AF is used as a probe device for the operation diagnosis and analysis of
It is difficult to use the device structure of M as it is. Further, when considering a voltage measuring system (EO system) utilizing the electro-optical effect as a voltage measuring means using laser light, it is difficult to combine it with an AFM probe with the conventional arrangement and structure.

That is, in the conventional arrangement / structure, the LSI
In order to obtain an AFM image of an LSI mounted on a driving device such as a tester, the sample portion becomes too large and the conventional AFM structure in which a sample is mounted on a three-dimensional stage and scanning / image acquisition is impossible. is there. Further, the lower surface of the mounting portion of the AFM probe and the voltage sensor portion has a wiring board for driving the LSI, a driving circuit and the like, and a considerably large free space is required for moving them, which is difficult with the conventional configuration. is there. In practical use, it is difficult to find a measurement wiring in an LSI chip of several tens of mm square by using only an AFM that can achieve a narrow visual field of 100 μm or less. Therefore, it is necessary to obtain a visual field of at least several 100 μm square. You need an optical microscope that can
It is difficult to arrange without interfering with the FM system and the EO system. In addition, in connection with this, an input section for a drive signal from an LSI tester or the like and a wiring board on which the LSI is mounted, or an LSI mounting base configured by a driving circuit or the like is mounted, and measurement wiring in a chip of several tens of mm square is mounted. There is no way to move it to search. Further, in the case of an LSI chip housed in a package, the chip is 0. Since it is provided at a portion recessed by several mm to 1 mm, the package wall and the AFM probe substrate collide with each other in the peripheral portion of the chip, and thus the measurement cannot be performed.

In order to eliminate such inconvenience, FIG.
In each of the examples shown in FIGS. 9 to 41, the following measures are taken. (A) A structure in which the scanning probe, the voltage sensor unit (EO sampling system), the cantilever displacement measuring unit, and the voltage measuring unit are all mounted on the fine movement stage, and fine movement of large parts such as the sample LSI and the drive circuit is unnecessary. .

(B) The fine movement stage has a single flat plate structure so that there is no protruding portion below the fine movement stage that interferes with the LSI, the wiring board necessary for driving the same, and the drive circuit. (C) The fine movement stage is mounted on the first coarse movement stage, and an optical microscope for large-field observation that is movable in synchronization with the first coarse movement stage is provided, and the optical microscope and the fine movement stage (scanning probe) are provided. And move as a unit,
The approximate position search of the measurement wiring was performed with an optical microscope, and the detailed position search and the positioning of the probe on the wiring were performed with a scanning probe.

(D) By mounting the entire three-dimensional fine movement stage on the rotary stage, the direction of the scanning probe can be arbitrarily changed, and the chip fixedly arranged in the recessed portion of the packaged LSI. The entire surface shape can be observed and probing is possible. (E) The fine movement stage is mounted on the frame mounted on the vibration isolation table,
The AF is installed together with the first coarse movement stage on which the SI mounting base is mounted, and the AFM probe is roughly positioned by the first coarse movement stage of the LSI mounting base to obtain an AFM image.
The M probe was moved on the fine movement stage.

(F) An optical microscope for large-field observation is mounted on a pedestal that is mechanically separated from the first coarse movement stage and the fine movement stage via the second coarse movement stage. The approximate position search can be performed with an optical microscope. By taking the above-mentioned means (a) to (f), the LSI mounted on the large-sized driving device is fixed, the optical microscope observation, the fine probe of the scanning probe and the voltage measurement by the laser beam, the LSI. It is possible to diagnose and analyze.

A detailed description will be given below with reference to FIGS. 39 to 41. FIG. 39 shows an example of a specific arrangement / structure. A performance board 402 is mounted on a station unit 400 of an LSI tester, which is an LSI driving device, and an LSI chip 406 to be diagnosed and analyzed is mounted on the board via an LSI socket 404. In addition, on the probe base 420 fixed on the LSI tester station unit 400, XY
Stages 430X, 4 capable of coarse movement in each Z direction
30Y and 430Z are mounted, and a coarse stage Z stage 430Z is provided with a rotary stage 440 that is rotationally driven by a motor 435. A fine movement Z stage 450Z driven by a piezo actuator 442 is engaged with the rotary stage 440, and the fine movement Z stage 450Z further includes a piezo actuator.
The fine movement XY stages 450X and 450Y driven by the actuator 444 are engaged. Each stage is controlled by driving means such as a pulse motor. The fine movement XY stages 450X and 450Y have a structure in which the central portion and the leaf spring forming portion are hollowed out from one plate (see FIG. 42), and the scanning probe 410 and the voltage sensor portion 416 are provided in the central portion. Support for holding (FIG. 42)
In 452). Further, a laser light source 412 for a laser beam for measuring cantilever displacement, a position sensor 414, and a voltage measuring unit 418 are mounted on the periphery of the fine movement XY stages 450X and 450Y.

An optical microscope 460 for large-field observation is mounted on the coarse movement Z stage 430Z via a mount 470. The optical microscope 460 includes a microscope mount 47.
Although it may be directly fixed to 0, for easier handling (for example, in order to retract the probe by a few millimeters during laser drilling of the insulating film or to clearly observe the tip of the probe, 3D stage 480X, 480 that can move about several mm (for adjustment, etc.)
It is desirable to mount via Y and 480Z. Also,
A laser light source 490 for opening a window of an insulating film such as an LSI passivation film or an interlayer insulating film is attached to the optical microscope 460, and the optical system of the optical microscope 460 is used in common to provide a sample surface (LSI surface) with a diameter of 1 to 1 mm. A laser beam of 2 μm can be emitted. In addition, 462 is a CCD camera and 464 is an objective part of the optical microscope 460.

FIG. 40 shows another example of the specific arrangement / structure. Here, the optical microscope 460 is configured completely independently of the LSI tester station unit 400 and the probe mount 420, and coarsely moves in each of the X, Y, and Z directions on a microscope mount 472 directly installed on the floor. It is mounted via possible stages 482X, 482Y, 482Z. With this configuration, since the height is relatively high, it is possible to eliminate the inconvenience that the shake of the optical microscope 460, which is easily affected by vibration, directly affects the AFM scanning system, and the AFM image can be stably obtained. There is an advantage that you can.

However, when performing a rough position search of the measurement wiring by the optical microscope 460, the second coarse movement stage (microscope stages 482X, 482Y, 482Z) is synchronized with the first coarse movement stages 430X, 430Y, 430Z. The scanning probe 410 can be always placed in the observation field of view and controlled, and if the first coarse movement stage is stopped and only the second coarse movement stage is moved, the scanning probe 410 can be moved. 410 is an LSI chip 406
It is possible that the optical microscope 460 goes out of the visual field without changing its relative position. Whichever control mode, 2
The relative positional relationship between the two coarse movement stages has a limit as apparent from FIG. Therefore, in order to prevent damage to the device due to carelessness, control is performed using relative coordinate data of both devices, and the movable range of the device is limited by a certain limiter.
It is desirable to provide.

FIG. 41 shows still another example of the specific arrangement / structure. In this embodiment, the first coarse movement stages 432X, 432Y, 432Z are mounted on the probe mount 422.
And an LSI mounting base 400a are mounted, and further LSI
Performance board 402, L on the mounting base 400a
The SI socket 404 and the LSI chip 406 are mounted in order. A rotation stage 440, which is driven to rotate by a motor 435, is provided in engagement with the probe mount 422. For other configurations, see FIG.
0 is the same as the embodiment. The LSI mounting table 400a
Is provided with a connector 401 for inputting an LSI drive signal. The LSI drive signal is transmitted from the connector 401 to the performance board 402 and the LSI socket 4.
It is supplied to the LSI chip 406 via 04.

Further, the optical microscope 460 has a second coarse movement stage (microscope stages 482X, 482Y, 482Z) on a microscope mount 472 directly installed on the floor.
Is installed through. In addition, 495 shows a vibration isolation mechanism. In the configuration of the present embodiment, when the rough position search of the measurement wiring by the optical microscope 460 is performed, it can be performed by moving the LSI chip 406 using the first coarse movement stage 432X, 432Y, 432Z.
It can also be realized by moving the optical microscope 460 using the coarse movement stages 482X, 482Y, and 482Z. However, the method of (2) has a limited range of movement, and in order to prevent inadvertent damage to the device, the range in which collision with the mounted object on the fine movement stage does not occur is determined in advance and the second coarse movement is performed. It is preferable to set a certain limit (limiter) on the coordinate value of the stage.

In either method, the optical microscope 46
If the measurement wiring can be placed within the field of view of 0, then the relative coordinates between the scanning probe 410 and the first coarse movement stage are known within a precision of a few tens of μm. Coarse movement stage of LSI chip 4
By moving 06, the target wiring can be easily put in the AFM field of view (about 100 μm square).

In this embodiment, the optical microscope 460 is used as the second coarse movement stage (microscope stages 482X, 4).
82Y, 482Z), the second coarse movement stage does not necessarily require the second coarse movement stage, although the second coarse movement stage increases the degree of freedom in observing the probe 410 itself and the sample LSI. FIG. 42 shows the fine movement stage (FIG. 39).
The configuration of the mounted object on the fine movement XY stages 450X and 450Y in FIG. 41 is shown. Here, the case where the electro-optical effect is used as the voltage measuring means by the light beam is shown.

The laser beam generated in the voltage measuring section 418 passes almost horizontally on the probe supporting section 452, and its direction is changed by a reflecting means such as a prism arranged on the electro-optic crystal of the voltage sensor section 416. And is incident on the electro-optic crystal. The light is reflected by the reflection film attached to the lower surface of the electro-optic crystal, follows the same path again, and returns to the voltage measurement unit 418,
After that, it is separated into two polarization components, and the voltage information is extracted. On the other hand, the laser light for measuring the cantilever displacement is generated from the laser light source 412 provided on the frame portion on the side of the fine movement stage, and is radiated to the cantilever of the scanning probe 410 via the mirror for adjusting the irradiation angle. The reflected light from the cantilever is detected by the position sensor 414 through an optical system including a detection angle adjusting mirror provided on the opposite frame portion.

In addition, the piezo actuator 444X, 2
Six leaf springs A to F are provided so that the stage can be finely moved in the two-dimensional direction by the pressing force of 444Y. FIG. 43 shows X for fine movement based on the action of the leaf spring.
The mode of operation of the Y stage is shown. In the figure, (a) shows the stage configuration when only the Y-direction piezo actuator 444Y is operated, and (b) shows the stage configuration when both the two-direction piezo actuators 444X and 444Y are operated. ing.

FIG. 44 is a diagram showing the reason why a rotary stage is required for probing a packaged LSI chip. In the figure, 404 is an LSI socket, 406 is an LSI chip, 406a is an LSI package, and 410 is a scanning probe. In the probing form as shown in FIG. 7A, there is a region R that cannot be measured, but as shown in FIG.
By rotating and changing the direction of the probe 410,
The entire surface of the LSI chip 406 can be observed, which in turn enables probing.

In this embodiment, the case where the probe is always in the visual field of the optical microscope has been described. However, as shown in FIG. For some, the working distance may not be sufficient. In that case, as shown in FIG.
It is also possible to selectively observe both microscopic images by separating them by about 0 to 50 mm).

As described above, according to the configurations of the embodiments shown in FIGS. 39 to 41, the voltage measurement of the fine wiring of the LSI mounted on the driving device such as the LSI tester is performed with high time resolution and space. This enables high resolution and high speed operation, and facilitates operation diagnosis and analysis inside a future VLSI. In each of the above-described embodiments, the case where the electro-optical effect is used as the voltage measuring means by the laser beam has been described, but the form of the voltage measuring means is not limited to this.

Next, regarding the arrangement and structure of the laser optical system for the low profile which contributes to the reduction of the device scale,
This will be described with reference to FIGS. 42 and 46 to 49.
In the inspection device using the light beam described above, in general, laser light is incident from the upper surface of the cantilever or the voltage sensor unit,
Further, since the optical path of the reflected light is also provided on the upper surface, there is a disadvantage that the configuration of the laser optical system becomes relatively large. That is, when performing internal diagnosis and analysis of the LSI, 1
It is necessary to find the target wiring (measurement wiring) from a large chip of 0 to 20 mm square. The ability to do this in a short time is an important factor in this type of analyzer. For this purpose, an optical microscope that can observe the entire chip from a wide range (low magnification) to a relatively narrow range (medium magnification) uses an AFM image (high magnification) with a fine probe.
It is essential to be able to use it together with. However, in a general inspection apparatus, even if an optical microscope is installed above, there is an optical path for a laser beam for cantilever displacement measurement, a laser beam for voltage measurement, etc. at this location, so it is extremely possible to realize it without mutual interference. Have difficulty.

Therefore, in this embodiment, a low profile laser optical system is realized by constructing the optical paths of the displacement measuring laser light and the voltage measuring laser light so as to be within the narrowest possible height range. . Specifically, the principle is to use a laser beam that is almost horizontal, and a laser beam reflection means is provided in the immediate vicinity of the laser beam irradiation target, so that the target (cantilever reflection surface or voltage sensor surface) is attached at a predetermined angle. It was possible to enter. With the above configuration, the laser optical path can be set within the height range of several tens of mm, and the installation space for the optical microscope can be secured.

Hereinafter, a specific description will be given with reference to the drawings.
Referring again to FIG. 42, the laser beam for measuring the cantilever displacement is radiated in a substantially horizontal form from the direction orthogonal to the longitudinal direction of the cantilever, unlike the normal AFM device, and the reflected light is in the opposite direction. The laser beam is detected (in a normal device, the laser beam is incident on the cantilever surface almost perpendicularly). In addition, the laser beam for voltage measurement is substantially horizontal from the root of the probe supporting portion 452, and is substantially vertical to the electro-optical crystal by the reflecting means (prism) provided on the electro-optical crystal of the voltage sensor portion 416. The light reflected by the reflecting surface on the back surface of the crystal follows almost the same optical path. The reflected light of the displacement measuring laser light is detected by the position sensor 41.
At 4, the laser beam spot position is measured, and the cantilever displacement amount is calculated from the measured value. In addition, the reflected light of the voltage measurement laser light is measured as the intensity of each component of P-polarized light and S-polarized light by the polarization component analysis unit provided in the voltage measurement unit 418 and converted into a voltage measurement value.

FIG. 46 shows the PP ′ line and the Q- line in FIG.
A cross-sectional configuration along line Q'is schematically shown. From these figures, it can be seen that a sufficient space for disposing the objective section of the optical microscope can be secured above the scanning probe 410. FIG. 47 shows the optical paths of the two laser beams in FIG. 42 in detail. Here, if the laser light for irradiating the displacement measuring laser light is reflected on the cantilever by the irradiation light adjusting mirror 413a, the direction of the reflected light is increased particularly in the Y direction due to a slight displacement (bending) of the cantilever. change. This is observed as a vertical displacement by the laser light position sensor 414 installed at the base of the probe support 452 by the two reflection mirrors 413b and 413c.

Further, when the displacement measuring laser beam is made to pass below the cantilever by the adjusting mirror 413a (sample surface position detection mode), the laser beam for displacement measurement is set at different places depending on the relative height between the sample surface and the probe section. Scattered. Therefore, if the laser passage position in the sample surface position detection mode is determined in advance, the position of the scattering point on the sample is observed with an optical microscope, and the height is adjusted so that the scattering point becomes the predetermined position. Then, the probe height can be easily adjusted. In FIG. 47, reference numeral 410 is a scanning probe including a cantilever, a substrate and a fine probe, 416a is an electro-optic crystal, and 416b is a reflection means (prism) provided on the crystal.

FIG. 48 shows another example of the optical path of laser light for realizing a low profile laser optical system. In this case, the laser light for voltage measurement is the same as in the above embodiment. The laser light for displacement measurement is supplied from a laser light source (not shown) provided at the base of the probe supporting portion 452 to the probe supporting portion 4.
The light beam follows an optical path substantially parallel to 52, is reflected by the mirror 415, is reflected by the reflecting surface of the cantilever, and is then reflected by the end surface of the substrate of the probe 410a, and then is reflected by the mirror 4.
It is reflected again at 15 and measured by a position sensor (not shown) installed at the base of the probe support 452. Similar to the case of FIG. 47, the present embodiment is also characterized in that the incident angle of the laser light on the cantilever reflecting surface is 70 to 80 ° (incident angle to the normal line), which is larger than that of a normal AFM.

FIG. 49 shows still another example of the optical path of laser light for realizing a low profile laser optical system. In this case, both the voltage measuring laser beam and the cantilever displacement measuring laser beam follow an optical path substantially parallel to the probe supporting portion 452, and are respectively reflected by the two reflecting means (prisms 416c and 416d) provided in the probe portion 410. The incident light is perpendicularly incident on the electro-optic crystal 416a and the cantilever portion, and the reflected light follows the respective optical paths in reverse.

When the voltage is measured by utilizing the electro-optic effect, the detection signal (for example, the photodetectors 24a, 24 in FIG. 2) is used.
It is necessary to know in advance the correspondence relationship between the output of b) and the measured voltage. However, when the wiring voltage is guided to the electro-optic crystal by the fine probe, in order to obtain the correspondence, it is necessary to bring the fine probe into contact with the wiring to which a known voltage is applied to perform signal detection. Further, for example, in order to obtain the impedance of the sample wiring, it is necessary to be able to measure both the voltage and the current, but there is a disadvantage that each of the above-mentioned devices can only measure the voltage. Further, if the probe is moved quickly when the probe is brought close to the sample in order to measure the sample shape and the sample voltage, the probe and the sample may collide.

In order to eliminate such an inconvenience, in this embodiment, an electrode is provided in the substrate holding portion of the cantilever, a switch is provided inside the holding portion or inside the cantilever substrate, and the probe potential can be controlled from the outside by the switch. I am trying. FIG. 50 shows an example of the configuration. In the figure, 500 is a scanning probe, 502 is a fine probe, 5
Reference numeral 04 is a conductive cantilever, 506 is a substrate supporting the cantilever, 508 is an electro-optic crystal, and 510 is EO.
Transparent electrodes for transmitting sampling laser light, 5
Reference numeral 12 is an electrode for reflecting a laser beam connected to the probe 502 via the cantilever 504, 514 is an electrode for switching,
Reference numeral 516 is a holder connecting electrode, and 518 is a switch for switching the connection between the probe-side electrode 512 and the holder connecting electrode 516 based on a control signal applied to the electrode 514.
Further, 520 is a holder for holding the probe 500, and 522 is an external variable power source (pulse generator or the like).
An electrode 524 for connecting the voltage signal from 530 to the holder connection electrode 516 and an electrode 524 for connecting the switch control signal to the switch electrode 514. According to this configuration, since the variable power source 530 can be connected to the wiring drawn out from the fine probe 502 via the cantilever 504, the electrode 512, the switch 518, the probe holder 520, etc., the detection signal-measured voltage Correspondence can be obtained.

Since the transparent electrode 510 on the side opposite to the probe-side electrode 512 of the crystal 508 must be set to some electric potential, an electrode connected to the transparent electrode is added, though not shown in the figure. Good. Further, although the switch 518 is built in the substrate 506 in the illustrated example, it may be provided inside or outside the holder. However, especially when measuring a high-speed signal, it is necessary to make the capacitance when the probe comes into contact with the wiring as small as possible, so the example in the figure is most preferable. Further, when the switch is built in the substrate, it may be integrated.

A method of acquiring the correspondence between the detection signal and the voltage will be described below with reference to FIG. Detection signal S
The relationship between the voltage V and the voltage V is as follows from FIG.
It is shown by the following formula. V = a + b × S …………………………………… (1) However, a and b are constants. By knowing the constants a and b in this equation in advance, the wiring voltage can be immediately known from the detection signal obtained when the probe contacts the wiring. To obtain the constant of the equation (1), a detection signal S _L when a known voltage V _L is applied to the probe electrode and voltage measurement is performed by the electro-optical effect, and a detection signal S _L when the voltage V _H is applied are detected. The signal S _H may be calculated by substituting it into the equation (1).

The number of applied voltage points is not limited to two,
By further increasing the number, the accuracy of the obtained constant can be improved. At this time, in addition to the method of applying a DC voltage to the probe electrode, there is also a method of applying a pulse signal (rectangular wave) to switch the measurement phase to obtain two sets of voltage and detection signal. When the pulse signal is applied, the phase control speed is faster than the voltage control speed, and therefore, there is an advantage that the processing can be performed at high speed.

Next, a method of measuring the circuit characteristics of the wiring portion will be described with reference to FIG. Various circuit characteristics can be known by applying a voltage signal from the pulse generation source 530 to the probe electrode and measuring the voltage by the electro-optical effect. For example, from the change in the voltage measurement value when the probe and the wiring 9 are in contact with each other (see FIG. 52B),
It is possible to know the input impedance, frequency characteristic, etc. of the probe contact point of the sample wiring 9 or the element connected to that point.

Further, as a matter of course, when performing an operation test of the input / output signals of the LSI to be tested by an LSI tester or the like, it can be used as a simple power supply probe for supplying an electric signal to the probe electrode. Next, a high speed control method of the height of the probe will be described with reference to FIG. A capacitance when the probe approaches the wiring 9 by connecting the capacitance measuring unit 540 to the probe electrode (probe 500) and using the probe height control unit 542 (specifically, the Z-direction moving stage described above). By detecting the change, the approximate height of the probe can be known. As the capacitance measuring unit 540, for example, a phenomenon of resonating at a specific capacitance when a signal of a predetermined frequency is applied can be used. Although this method cannot be expected to detect height with high accuracy, it has an advantage that it can be applied in a relatively wide range. By making the probe approach the wiring while monitoring the capacitance (that is, the probe height) and acting as a stop switch that stops the approach at a certain capacitance height, coarse control of the probe height can be performed at high speed. It can be carried out.

Next, a preferred embodiment for observing the surface shape without damaging the sample will be described with reference to FIGS. 54 to 58. When the signal of the LSI is to be measured by electrically contacting the fine probe and the LSI wiring, it is necessary to harden the cantilever in order to obtain sufficient electrical contact. However, when the cantilever is hard, observing the surface shape by a conventional method may damage the sample surface by the probe when the probe is moved in the horizontal direction. Dozens of μ to determine the measurement point of LSI wiring
When observing a wide area of about m square, the horizontal movement speed of the probe is high, so that the risk of damage becomes high. Also, LSI
In order to measure the voltage at a predetermined point of the above, it is necessary to determine the measurement position from the observation result of the surface shape, move the probe horizontally to that position, and then have the function of fixing the probe. Shape observation by discrete movement of the probe is preferable.

In order to solve such a problem, this embodiment provides the following means. (A) As shown in FIG. 54, the probe 552 of the scanning probe 550 is brought closer to the sample 560 from above (corresponding to scanning), and the sample surface shape is determined by the point where the probe 552 contacts the sample 560. To know However, the contact point is defined as follows (see FIG. 55).

When the probe 552 is brought closer to the sample 560, the probe is attracted to the sample immediately before the contact, and when it further approaches a certain limit, the cantilever 554 begins to bend because it cannot be brought closer by repulsive force. That is, when the cantilever is sufficiently soft, the probe does not strictly contact the sample. However, when the cantilever is hard, the force generated by the bending overcomes the repulsive force, so that the probe comes into contact with the sample and damages the sample. Therefore, damage to the sample can be prevented by setting the point Z _{0 at} which the probe starts to be pulled by the sample by the attractive force as the contact point and stopping the approach at this point.

Further, the hardness of the cantilever is further increased,
When the bending in the opposite direction due to the attractive force cannot be detected, the point Z _{1 at} which the bending starts in the plus direction in FIG. 55 is defined as the contact point. (B) When the probe 550, that is, the probe 552 is horizontally moved (corresponding to scanning of, in FIG. 54), the probe height is feedback-controlled so that the deflection amount of the cantilever 554 becomes constant. At this time, in order to shorten the image acquisition time, it is necessary to shorten the horizontal movement time of the probe. However, if the feedback response speed is increased in accordance with this, the height may vibrate unstable when the horizontal position of the probe is fixed as in the case of voltage measurement. Therefore, the feedback control is effective only when the probe moves horizontally.

A detailed description will be given below with reference to the drawings. FIG. 56 shows a configuration example for realizing the probe control method corresponding to the above means (a). In the figure, a contact detection unit indicated by 570 is a characteristic portion which the conventional device does not have. The operation of each unit will be described below.

The light emitted from the laser light source 572 is reflected by the cantilever 554 and enters the angle detecting light receiver 574. The light receiver 574 for angle detection is the cantilever 55.
A signal proportional to the reflection angle that changes according to the bending of No. 4 is output. When observing the sample surface shape, the horizontal movement mechanism (not shown) moves the probe 552 or the sample 560 to the observation point, and the probe vertical movement mechanism 576 starts descending the probe 552. When the probe descends, the contact detector 570 monitors the angle signal (= deflection amount signal) from the light receiver 574, and immediately when the probe 552 contacts the sample 560, the probe height controller 578 immediately receives the “contact point”. A contact signal indicating “arrival” is transmitted. In response to the contact signal, the probe height control unit 578 instructs the probe vertical movement mechanism 576 to stop the probe descending, and after outputting the height at this time, raises the probe 552 to a fixed amount or a fixed position. Instruct. The above operation is repeated to measure the surface shape.

The operation of the contact detector 570 will be described in more detail. When the probe 552 is sufficiently separated from the sample 560,
The bending amount of the cantilever 554 is 0, and is registered (set) with this as a reference. Since the output from the photodetector 574 contains noise, the noise amount when the flexure amount is 0 is used as a threshold value, and the photodetector output (deflection amount signal) is greater than or equal to the threshold value by more than the threshold value. When it changes to, a contact signal is output. Therefore, since the height resolution is determined by the noise of the output signal of the light receiver 574, in order to improve the height resolution, the light receiver output signals may be averaged or the height may be measured a plurality of times. .

FIG. 57 shows a configuration example for realizing the probe control method corresponding to the above means (b). Here, only the case of movement in one direction (X direction) is shown, but the same applies to the case of two dimensions. The operation of each unit will be described below. The horizontal position X is set in the X register 582 by the computer CPU (not shown) and the image scanning counter 580. This data is converted into an analog signal by the D / A converter 584, and then the low pass filter (LPF) 5
It is sent to the X position braking unit 588 via 86. The X position braking unit 588 moves the X stage (not shown) by the designated voltage. At this time, the X position designation voltage is L
Since it goes through the PF 586, it changes slowly as shown in FIG.

On the other hand, the cantilever displacement detector 590 observes the amount of bending of the cantilever. The deflection amount measurement value and the value preset in the displacement designation unit 592 are subtracted by the differential amplifier 594, and the Z position braking unit 5 is passed through the switch 596.
Sent to 98. Thereby, control is performed so that the distance between the sample and the probe is kept constant. Also, LPF58
The voltage at the input / output terminal of 6 is input to the comparator 600, and
As shown by, the start (time point of t1) and the completion (time point of t2) of the voltage change are detected. With this detection signal,
Feedback to the Z position (that is, height) braking unit 598 is turned on / off. That is, the height feedback control is effective only while moving in the X direction. here,
The movement in the X direction needs to be slow enough compared to the feedback response speed. Reference numeral 602 denotes an A / D converter that converts the output signal of the Z position braking unit 598 into a digital signal, and 604 denotes an image display unit that displays a digitized image signal.

Although the LPF 586 is used in the configuration example of FIG. 57, a configuration using a ramp waveform generating circuit instead or a configuration using a digital adder / subtractor in front of the D / A converter 584 in the preceding stage may be used. Good. The point is that the specified voltage change is sufficiently slower than the response speed of the height feedback as shown in FIG. 58, and the start and completion of the change can be detected.

Next, FIG. 5 shows an example suitable for ensuring the electrical contact between the fine probe and the wiring at the time of voltage measurement.
This will be described with reference to FIGS. When voltage measurement is performed using the AFM function, the wiring must first be detected and the probe must be moved to the voltage measurement position. Next, it is necessary to press the probe against the wiring with a force sufficient to make electrical contact. Wiring is generally more prominent than the surrounding insulator, but in some cases, the wiring is buried in the insulator and there is no difference in height between the wiring and the surrounding area, or the entire insulation film is used. Is covered and the insulator near the wiring must be removed by electron beam or laser beam to measure voltage (again, there is no difference in height)
Cases must also be considered. Also, when electrically connecting the probe to the wiring, it is necessary to consider the case where the wiring surface is covered with an oxide film.

In view of such a situation, this embodiment provides the following means. (1) Means for searching the position of the wiring The wiring position is obtained from the one-dimensional or two-dimensional scanning image of the wiring surface obtained by the function of the AFM (see FIG. 59). If the hardness differs depending on the material of the sample, the amount that the probe bites into the sample surface when the probe is pressed against the sample is different (see Fig. 60 (a)). If it is small, it is considered to be soft, and if it is large, it is judged to be hard. The wiring position is obtained from the hardness image obtained by performing this operation while changing the horizontal position of the probe (see FIGS. 60 (b) and 60 (c)).

When any signal is applied to the wiring, the wiring position is obtained from the measurement result when the probe is horizontally scanned while measuring the voltage (see FIG. 61). When the probe side electrode (for example, the electrode 4 in FIG. 2) is electrically floating, the electric field inside the electro-optic crystal is irrespective of the signal applied to the transparent electrode (electrode 3 in FIG. 2) on the opposite side. Is almost 0. Therefore, it is used that the difference between the wiring voltage and the applied voltage between the transparent electrodes appears inside the crystal when the probe contacts the wiring and the potential of the probe-side electrode is determined. That is, a pulse signal is applied to the transparent electrode (see, for example, FIG.
In step (supplying a pulse signal from the variable power source 29), the wiring position is obtained from the voltage amplitude measurement result when the probe is horizontally scanned while performing voltage measurement. (2) Means for guaranteeing electrical connection between wiring and probe The electrical connection is established by pressing a certain amount based on the wiring height obtained by the function of the AFM (Fig. 62).
reference).

The constant pressing at this time means (a) bringing the probe height closer to the sample by a fixed amount, or (b) bringing the probe closer to the sample so that the cantilever deflection amount increases by a fixed amount. Is either. Similar to (1) described above, the microprobe is brought close to the sample little by little while performing voltage measurement, and the electrical connection is determined from the obtained measurement result (see FIG. 63).

As in (1) above, a pulse signal is applied to the transparent electrode to measure the voltage, and the probe is brought into close proximity to the sample little by little, and the electrical connection is determined from the voltage amplitude measurement result. To do. The flow chart of FIG. 64 shows a high level for ensuring wiring position search and electrical connection by applying a pulse signal asynchronous with the sample to the transparent electrode and performing voltage measurement (in-crystal electric field measurement) by the apparatus configuration of FIG. The measurement procedure from the determination of the depth to the voltage measurement is shown.

First, in step 650, a pulse signal is applied to the transparent electrode. Next, the electrical contact is confirmed at each horizontal position while performing horizontal scanning (step 651,
652,658). Although only the X direction is described in the figure,
If two-dimensional scanning is desired, the basic procedure is the same except that a double loop of X and Y is used. An electrical height search is performed while moving X in increments of ΔX from the scan start position Xa of X to the scan end position Xb (steps 653 to 653).
656). In the search, while gradually lowering the probe height in steps of ΔZ (step 656), measuring the voltage amplitude (step 654), the deflection of the cantilever reaches a limit,
Alternatively, when the measurement amplitude is not 0 and does not change (that is, when the electrical contact is made sufficiently), the process ends (step 65).
5).

When the horizontal search is completed, a one-dimensional profile of the measured amplitude with respect to the horizontal position is obtained.
Based on this, the horizontal position for measurement is determined by, for example, detecting the center of gravity (step 659). The height is detected at the determined horizontal position, the probe is pressed against the wiring so as to make sufficient electrical contact (step 660), the pulse application to the transparent electrode is stopped (step 661), and the voltage is measured. (Step 662).

During these operations, if no electrical contact can be obtained even if the bending amount is pushed to the limit, the point on the sample is an insulator, or the point is disconnected and electrically floated. It can be determined that the wiring. In the method of measuring voltage using the electro-optic effect, the difference between the two polarization-separated light detection signals detected by the photodetector such as a photodiode is proportional to the electric field strength in the electro-optic crystal (that is, the voltage at the measurement point). Therefore, this detection signal (for example, the photodetector 2 in FIG. 2)
The crystal applied voltage can be measured by obtaining the difference signal (outputs of 4a and 24b). However, in this case, the voltage value cannot be directly known from the detection signal unless the proportional coefficient of the difference signal and the voltage is known.

In order to deal with this inconvenience, in this embodiment, the proportional coefficient between the difference signal of the detection signal and the voltage is determined in advance. FIG. 65 shows a configuration for determining the proportional coefficient and performing voltage measurement using the proportional coefficient. The configuration shown is, for example, a portion included in the wiring detection / contact control unit 17, the system control unit 18, and the voltage measurement control unit 26 in FIG. In the figure, 670 is a voltage value conversion unit for converting a detection signal, that is, the difference signal S (t) into a voltage V (t), and 672 is a conversion coefficient (that is, a conversion coefficient) based on the data of the electrode film voltage or the known voltage and the detection signal. 3 shows a conversion coefficient determination unit that determines a proportional coefficient C ₀ , C ₁ ). The following three methods are conceivable as the method of determining the proportional coefficient by the conversion coefficient determining unit 672. (1) Method using the zero point method (see FIG. 66) First, the probe is moved to the operation wiring position (step 70).
1) and contact (step 702). Next, the voltage is measured by the zero point method while scanning the measurement phase t to obtain the voltage waveform (steps 703 to 710). The voltage measurement by the zero point method means that the transparent electrode film voltage is controlled by using the binary search method as shown in steps 705 to 710 so that the difference signal of the detection signals becomes zero. In this method, the voltage applied to the transparent electrode film is used as the wiring voltage.

Next, the voltage of the transparent electrode film is set to 0V (step 711). Further, the difference signal is measured while scanning the measurement phase t to obtain the difference signal waveform (step 71).
2-715). Next, proportional coefficients C ₀ and C ₁ that determine the correspondence are determined from the voltage waveform and the difference signal waveform (step 716). Thereafter, the probe is moved / contacted to the wiring to be measured to measure the difference signal, and the voltage value conversion unit 670 immediately converts the difference signal into a voltage value and outputs the voltage value. . (2) Method of using power line and GND line (Fig. 6
7) First, move the probe to the GND line (step 73).
1) Contact them (step 732) and measure the difference signal (step 733). Next, the probe is moved to the power line (step 734) and brought into contact (step 73).
5), measuring the difference signal (step 736). Then
From the difference signal detection results (S ₁ , S ₂ ) corresponding to the power supply voltage value and the GND voltage value, the proportional coefficients C ₀ , C ₁ that determine the correspondence are determined (step 737).

After that, in the same manner as in the method (1), the probe is moved / contacted to the wiring to be measured to measure the difference signal,
Using this difference signal and the proportional coefficient determined above, it is converted into a voltage value and output. (3) Method of using input pad (see FIG. 68) First, the voltage of the signal input pin of the device under test is measured using a sampling oscilloscope, an LSI tester or the like to obtain the voltage waveform V (t) (step 751). ). Next, the probe is moved (step 752) and brought into contact with the pad directly connected to the pin for which the voltage measurement has been performed (step 753). Next, the difference signal is measured while scanning the measurement phase to obtain the difference signal waveform S (t) (step 7
54). Next, the proportional coefficients C ₀ and C ₁ that determine the correspondence are determined from the voltage waveform and the difference signal waveform (step 75).
5).

Thereafter, similarly to the methods (1) and (2), the probe is moved and brought into contact with the wiring to be measured, the difference signal is measured, and this difference signal and the proportional coefficient determined above are calculated. Used to convert to voltage value. Next, the packaged LSI
An example suitable for observing the chip surface of (1) without any hindrance during voltage measurement will be described with reference to FIGS. 69 to 73.

When a probe of the type in which an electro-optic crystal is installed on a probe substrate as shown in FIGS. 1 and 5 is used while being held by a holder, for example, as shown in FIG. ) L
Inconvenience occurs when observing the surface of the SI chip 802. That is, since the chip 802 is arranged at a position deeper than the surface of the package 800 (for example, 1 mm), a part of the holder 812 (in some cases, a part of the probe 810) is provided at the peripheral portion of the deep part of the package. The LSI chip 802
The tip of the probe of the probe 810 cannot be brought into contact with the surface of the probe 810, and the observation region is limited. In the illustrated example, the portion indicated by R is an unmeasurable region. In order to deal with this, it is conceivable to increase the inclination of the probe with respect to the sample surface, but in this case, the probe also inclines with respect to the sample surface according to the inclination angle of the probe, so the line profile measurement is performed. At the same time, the probe wall surface comes into contact with the wall surface of the convex portion such as the wiring on the sample surface, which distorts the observed image and lowers the spatial resolution.

In order to eliminate such an inconvenience, this embodiment provides the following two modes. (A) First embodiment (see FIGS. 70 to 72) In the configuration illustrated in FIG. 70, the first substrate 822 that supports the cantilever 820 having the fine probe at the tip is an electro-optic crystal, and further on this crystal. A second substrate 830 is formed on
The feature is that the entire probe is held by holding the second substrate. The cantilever 820 equipped with a probe is adhered to the lower part of the first substrate 822, and a gold (Au) film 824 is adhered to the lower part of the electro-optic crystal to reflect the laser beam P ₃ for voltage measurement. A transparent conductive film 826 is adhered to the upper part to transmit the laser light. The second substrate 830 has a vertically long structure extending upward to facilitate holding, for example, 1
It has a length of about 5 mm in a square section of mm, and
It is made of, for example, glass or the like for transmitting a laser beam for voltage measurement. Further, the transparent conductive film 826 on the electro-optic crystal (first substrate 822) is grounded (GND).
The wiring pattern 828 is formed on the second substrate 8 so that it can be grounded to
It is formed along the side surface of 30. In this embodiment, the laser beam P ₃ for voltage measurement and the laser beam P ₁ for cantilever displacement measurement are applied to the probe in the vertical direction.

As described above, according to the structure of this embodiment, since the vertically elongated probe structure extends upward, positioning and the like are facilitated during holding, and almost the entire surface of the packaged LSI chip is It becomes possible to observe the area. FIG. 71 shows a modification of the above embodiment,
A voltage measurement laser beam P ₃ so as to be irradiated from the horizontal direction with respect to the probe, means for changing the optical path to the second substrate 830a top, an example in which, for example, a prism 832, a mirror or the like. This configuration example contributes to the realization of the above-described low profile laser optical system. It should be noted that, by forming the second substrate 830a so as to extend in each of the X, Y, and Z directions as illustrated, it becomes easy to hold the present probe by the probe holder portion 834 with high positional accuracy.

FIG. 72 shows another modification, in which the laser beam P ₁ for measuring cantilever displacement is measured from a direction (X direction in FIG. 71) substantially orthogonal to the longitudinal direction of the cantilever 820 (Y direction in FIG. 71). This is an example of irradiation of a cantilever. (B) Second Mode (see FIG. 73) In the configuration illustrated in FIG. 73, a part of the cantilever 850 is bent so as to have a convex shape with respect to the surface of the sample 840, and one end of the cantilever has an insulating property. Fixed to the probe substrate 854 held by the probe holder 852,
The cantilever 850, the bottom surface of the probe substrate 854, and the bottom surface of the probe holder 852 are largely inclined with respect to the surface of the sample 840 so that the probe 856 formed on the other end of the cantilever 850 abuts the surface of the sample 840 almost vertically. It is characterized by doing. Specifically, the probe 856 is attached to the convex direction of the bent cantilever 850, and the probe substrate 854 having a triangular side cross section is used. The probe as a whole has a probe 856 mounted on a probe holder 852 which is arranged with its bottom surface largely inclined.
It is mounted perpendicular to the 0 surface. Note that 858 indicates an electro-optic crystal.

As described above, according to the structure of the present embodiment, since the probe 856 is perpendicular to the surface of the sample 840, there is no deterioration in spatial resolution, and the bottom surface of the entire probe apparatus with respect to the surface of the sample 840. Since the angle is large, the LSI
Except in the special case where the edge of the chip and the wall of the recessed part of the package are very close to each other, almost the entire area of the surface of the LSI chip can be observed. This is the LSI
This contributes to the improvement of inspection accuracy and efficiency.

In the embodiment of FIG. 73, the laser beam for measuring the cantilever displacement is applied to the tilted part of the cantilever, but it is also possible to apply it to the horizontal part of the cantilever. Of course, it is not limited. Further, the mounting position of the electro-optic crystal is not limited to this example, and the voltage measurement method using laser light is not limited to this example.

The probe manufacturing method of this embodiment may be a method in which the cantilever is mechanically bent, but the following method can be considered as a more suitable manufacturing method. First, a pyramid-shaped hole is formed in a (100) Si substrate by anisotropic etching. The wall surface of the hole is the (111) plane and has an inclination of 55 °. Then, one side of the pyramid-shaped hole is cut out and a metal (for example, A
u) Form a film. This constitutes a cantilever. Next, a probe substrate is bonded to the cantilever, and a conductive fine probe is formed by metal vapor deposition via a mask. Next, a metal film for applying the voltage of the probe to the electro-optic crystal is formed on the probe holder, and then Si is etched to form a cantilever.

Alternatively, it can be manufactured by the following method. A metal (for example, Cr) film is formed on a Si substrate and patterned to form a conductive fine probe. Next, a probe substrate is adhered to the cantilever, a metal film is further formed on the surface on which the electro-optic crystal is attached, and then Si is etched to form the cantilever. Next, a metal (for example, Au) film having a stress larger than that of the material of the cantilever is attached to the surface of the cantilever opposite to the probe, so that the cantilever is curved in a convex shape. The angle of warp can be controlled by the film thickness or the like.

Next, a preferred embodiment for facilitating sample observation and wiring search will be described with reference to FIGS. 74 to 77. Generally, in order to shorten the measurement time in the internal diagnosis and analysis of the LSI, it is necessary to find the wiring to be measured in a short time. In this case, a means for observing the surface of the LSI chip (for example, an optical microscope) is used.
In the search process, the cantilever portion provided on the probe becomes a shadow, and it is difficult to find the target area on the surface of the LSI chip.

In order to eliminate this inconvenience, this embodiment provides the following two modes. (A) First mode (see FIGS. 74 and 75) In the configuration illustrated in FIG. 74, an optical microscope 870 for observing the surface of the LSI chip is provided and electrically connected to the fine probe 6. Moreover, it is characterized in that the wavelength filter 5A is formed on the surface of a conductive cantilever which can be bent (displaced) by an extremely small force received by the probe.

FIG. 75 shows the relationship between the reflectance of the cantilever and the wavelength of light. As shown in FIG. 75, the wavelength filter 5A is the observation light of the optical microscope 870 for observing the surface of the LSI to be measured. by transmitting for light having a wavelength lambda ₁ or less of the wavelength of the wavelength of the displacement measurement laser beam lambda
_It has the property of reflecting light with wavelengths near _two . Therefore, the surface of the LSI chip can be observed by the microscope 870 through the cantilever 5A with wavelength filter, and the displacement of the cantilever 5A can be measured by the displacement measuring laser beams P ₁ and P ₂ . The wavelength filter 872 inserted below the optical microscope 870 is a wavelength filter for generating microscope observation light having a wavelength of λ ₁ or less. However, as described above, the cantilever 5A itself has a filter function. Therefore, it is not always necessary to dispose this wavelength filter 872.

(B) Second Mode (see FIGS. 76 and 77) The configuration illustrated in FIG. 76 is characterized in that the conductive cantilever 5B is made transparent as compared with the configuration of FIG. FIG. 77 shows the relationship of the reflectance of the cantilever with respect to the incident angle of laser light. For example, the cantilever 5B and the fine probe 6 were made of Si ₃ N ₄ and the cantilever 5 was manufactured.
In order to make the thickness of B part 1 μm and to have conductivity, I
The characteristics when the TO electrode is attached to a 700 angstrom film are shown.

When a laser beam for displacement measurement is incident from the upper surface (almost vertical direction) of the cantilever as in the conventional AFM, the laser beam is hardly reflected by the cantilever and is transmitted as shown in FIG. Therefore, it is difficult to measure the displacement. Therefore, it is necessary to increase the incident angle of the displacement measuring laser beams P ₁ and P _{2 on} the cantilever 5B (for example, to about 60 degrees). In particular, when a laser beam of only S-polarized light is made incident, it is effective because the reflectance is high. Note that it is possible to obtain the required reflectance at an incident angle of 40 degrees, for example, by changing the method of forming the film of the cantilever 5B and the material. Also, cantilever 5B
Of the longitudinal direction to increase the angle of incidence of the displacement measurement laser beam, because the probe substrate 2 and the electro-optic crystal 1 is hinder displacement measurement beam, as shown, the displacement measurement laser beam P _1, P ₂ is The light is incident from a direction substantially perpendicular to the longitudinal direction of the cantilever 5B. With this configuration, it becomes easy to install an objective lens having a small working distance on the optical microscope 870 above the probe.

As described above, according to the configuration of this embodiment, the LS
In internal diagnosis and analysis of I, L through the cantilever
The SI chip surface can be observed with an optical microscope, and the target area of the LSI chip surface can be easily found. Therefore, the target wiring can be easily found, and the operability and the measurement time are improved. In the LSI inspection device in which the wiring voltage is guided to the electro-optic crystal by using the conductive fine probe as in each of the above-described embodiments, the probe is pressed against the wiring to be measured at the time of voltage measurement to obtain electrical continuity. I am trying. Therefore, repeated measurement causes problems such as wear and deformation of the probe. When the probe wears, an error occurs in a microscopic image obtained by mechanical scanning. Therefore, when the probe wears a certain amount or more, it is desirable to replace the probe. However, the replacement criteria of the probe, such as when and how the probe should be replaced, is not always clear.

Therefore, in the present embodiment, the above-mentioned inconvenience is solved by providing a means for judging whether or not the probe needs to be replaced. In this case, the following two forms are recommended. (A) A graph of the control voltage applied to the fine movement mechanism with respect to the atomic force acting between the probe and the sample (hereinafter referred to as force curve [see FIG. 78]) is used. The atomic force responds sensitively to the distance between the probe and the sample, and for example, the distance is 10 n.
When it becomes about m, it becomes an attractive region, and when the probe is further brought close to and brought into contact with the sample surface, repulsive force works. When the probe wears, there is an offset in the initial force curve. Therefore, wear of the probe can be determined by detecting this offset amount.

(B) If the probe wears, force
Since the curve has an offset, the image obtained by the AFM also has an offset overall. Therefore, the wear of the probe can be determined by calculating the average offset amount of the entire image. Hereinafter, a specific example corresponding to the above modes (a) and (b) will be described. FIG. 79 shows an operation sequence based on the form (a).

First, in step 901, the LSI (device) to be tested is set, and in the next step 902, the point where the force curve is acquired to determine the wear is determined. This point may be any point in the device, but it is preferable that the area is sufficiently larger than the tip portion of the probe, for example, on an area having a size of a pad in the chip, and actually Use a location different from the point where the voltage is measured. In the next step 903, the coordinates of the determined acquisition point are saved (stored). The data regarding the coordinates includes data regarding the X, Y, Z coordinates of the coarse movement mechanism and data regarding the X, Y, Z control voltages applied to the fine movement mechanism.

Next, at step 904, the AFM of the neighborhood
Get the image and save it in correspondence with the coordinates.
Next, in step 905, a force curve is acquired and this data is stored. In the next step 906, the inspection L
After performing a series of SI voltage measurements, in step 907,
Move the probe to the saved coordinates (that is, the force curve acquisition point). However, at this time, it does not always return to the original point depending on the backlash and accuracy of the coarse movement stage (see FIG. 80).

Therefore, in the next step 908, an AFM image is acquired, and in step 909, the stored data (AFM image data) is compared, and in the next step 910, an error ( That is, it is possible to accurately return to the original point by calculating (positional deviation). When returning to the original point, the force curve is acquired again (see step 911). Finally, in step 912, the stored force curve and the force curve acquired in step 911 are stored.
When the curves are compared, the force curve is offset by an amount corresponding to the amount of wear of the probe (see FIG. 81).

The offset amount is measured by setting a threshold value in the repulsive force region as shown in FIG. 81 and detecting the difference in control voltage at this value. In addition, when measuring the offset amount,
In order to be able to distinguish from the offset caused by the drift of the piezoelectric element used for the fine movement mechanism, it is necessary to use a piezoelectric element that has a small movement amount and has no hysteresis using a strain gauge or the like to make the drift amount extremely small. is there.

Further, as a specific example based on the form (b), there is a method of measuring the offset amount of the AFM acquired image. In this case, the operation sequence is almost the same as that of the above-mentioned embodiment, except that the acquired image is used instead of the force curve. The stored data and the used data are offset by the amount of wear of the probe, as in the case of using the force curve. Therefore, the amount of wear can be determined by calculating the average offset amount of the entire image.

This measurement of the amount of wear is always measured and stored every time the LSI (device) to be tested is replaced. Even if the same device is used, if the number of times of voltage measurement is large, the wear amount is measured according to the number of times of measurement. In this case, the total wear amount is calculated by adding the measured wear amount data, and when this value exceeds the predetermined allowable wear amount, it indicates that the probe has reached the end of its life (that is, the probe replacement time). It is also possible to generate a signal for

As described above, according to the configuration of this embodiment, it is possible to determine the life of the probe and to know whether or not the probe needs to be replaced.

[0146]

As described above, according to the present invention, it is possible to realize voltage measurement with improved spatial resolution and temporal resolution. Further, it is possible to make sufficient electrical contact with the fine wiring and to perform stable probing without increasing the electrical load on the fine wiring.
This greatly contributes to improving the accuracy of voltage measurement.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an embodiment of a probe device of the present invention.

FIG. 2 is a diagram showing an overall system configuration including the device of FIG.

FIG. 3 is a diagram showing an example of a polarization state of a sampling optical system.

FIG. 4 is a diagram showing another example of the polarization state of the sampling optical system.

FIG. 5 is a perspective view showing the configuration of another embodiment of the probe device of the present invention.

FIG. 6 is a flowchart showing a process for voltage measurement by the apparatus of FIG.

FIG. 7 is a diagram showing a first modification of the probe device of FIG.

8 is a diagram showing a second modification of the probe device of FIG.

9 is a perspective view showing the configuration of the probe device of FIG. 8. FIG.

10 is a diagram showing a third modification of the probe device of FIG.

11 is a perspective view showing the configuration of the probe device of FIG.

FIG. 12 is a perspective view showing the configuration of an embodiment of an LSI inspection apparatus of the present invention.

13 is a diagram showing a state of probing a wiring near a bonding wire by the apparatus of FIG.

FIG. 14 is a diagram showing a configuration example that enables the probing shown in FIG.

FIG. 15 is a diagram showing another configuration example that enables the probing shown in FIG.

FIG. 16 is a perspective view showing an overall configuration of an LSI inspection device including a gantry.

FIG. 17 is a diagram showing how the vibration isolation table tilts as the center of gravity moves due to rotation.

FIG. 18 is a diagram showing a first configuration example for fixing the relative positional relationship of the test LSI to the vibration isolation table.

FIG. 19 is a diagram showing a second configuration example for fixing the relative positional relationship of the test LSI to the vibration isolation table.

FIG. 20 is a diagram showing a third configuration example for fixing the relative positional relationship of the test LSI to the vibration isolation table.

FIG. 21 is a diagram showing a fourth configuration example for fixing the relative positional relationship of the test LSI to the vibration isolation table.

FIG. 22 is a diagram showing a configuration example for preventing interference between an optical microscope and a probe.

FIG. 23 is a diagram showing another configuration example for preventing interference between the optical microscope and the probe.

FIG. 24 is a diagram schematically showing the configuration of the probe scanning system in the embodiment of FIG. 12 in comparison with a normal AFM scanning system.

FIG. 25 is a diagram showing an arrangement example of stages for reducing the weight of a probe scanning system.

FIG. 26 is a perspective view showing an example of mounting an AFM stage suitable for weight reduction and size reduction.

27 is a perspective view showing the structure of the tip portion of the AFM stage of FIG. 26. FIG.

28 is a perspective view showing a configuration example in which the AFM stage of FIG. 26 is combined with a probe head stage.

29 is a schematic cross-sectional view taken along the line AA ′ of FIG. 28.

FIG. 30 is a diagram showing a configuration example of probe displacement detection means suitable for downsizing.

FIG. 31 is a plan view showing a configuration example of an AFM optical system suitable for weight reduction and size reduction.

FIG. 32 is a view showing an example of a probe attaching / detaching mechanism.

FIG. 33 is a view showing another example of a probe attaching / detaching mechanism.

FIG. 34 is a view showing a holding mechanism of a spare probe.

FIG. 35 is an L suitable for facilitating positioning of a voltage measurement point.
It is a block diagram which shows the structure of SI inspection apparatus.

FIG. 36 is a block diagram showing a configuration of an LSI inspection device capable of performing alignment correction by pattern matching.

37 is a flowchart showing a process for alignment correction by the apparatus of FIG.

38 is a flowchart showing a process for determining a probe contact pressure by the device of FIG. 36.

FIG. 39 is a partial cross-sectional view showing an example of a specific layout / structure of the LSI inspection apparatus of the present invention.

FIG. 40 is a partial cross-sectional view showing another example of the specific arrangement / structure of the LSI inspection apparatus of the present invention.

FIG. 41 is a partial cross-sectional view showing still another example of the specific arrangement and structure of the LSI inspection device of the present invention.

FIG. 42 is a perspective view schematically showing the configuration of a fine movement stage and its mounted product.

43 is a diagram for explaining the operation of the fine movement stage in FIG. 42. FIG.

FIG. 44 is a diagram for explaining the necessity of a rotary stage.

FIG. 45 is a configuration diagram in the case of selectively using an optical microscope and an AFM probe.

FIG. 46 is a schematic cross-sectional view taken along the line PP ′ and the line QQ ′ of FIG. 42.

FIG. 47 is a diagram showing in detail the optical path of the laser light in FIG. 42.

FIG. 48 is a diagram showing another example of the optical path of the laser light that realizes the low-profile laser optical system.

FIG. 49 is a diagram showing yet another example of the optical path of the laser light that realizes the low-profile laser optical system.

FIG. 50 is a diagram showing the configuration of a probe device in another embodiment of the LSI inspection device of the invention.

51 is a diagram for explaining a method of acquiring the correspondence relationship between the detection signal and the voltage by the device of FIG. 50.

52 is a diagram for explaining a method of measuring circuit characteristics by the device of FIG. 50.

53 is a view for explaining a method of controlling the height of the probe by the device of FIG. 50.

FIG. 54 is a diagram showing the concept of a probe control method suitable for preventing damage to a sample.

FIG. 55 is a diagram showing the relationship between the probe height and the bending amount of the cantilever.

56 is a diagram showing the configuration of an example for implementing the probe control method of FIG. 54. FIG.

FIG. 57 is a diagram showing the configuration of another embodiment for realizing the probe control method of FIG. 54.

FIG. 58 is an operation timing chart of each part in the configuration of FIG. 57.

FIG. 59 is a diagram for explaining an example of means for realizing a wiring position search.

FIG. 60 is a diagram for explaining another example of the means for realizing the wiring position search.

FIG. 61 is a diagram for explaining still another example of the means for realizing the wiring position search.

FIG. 62 is a diagram for explaining an example of means for ensuring electrical connection between the wiring and the probe.

FIG. 63 is a diagram for explaining another example of means for ensuring the electrical connection between the wiring and the probe.

FIG. 64 is a flowchart showing a process of voltage measurement based on a wiring position search and a guarantee of electrical connection.

FIG. 65 is a block diagram showing a configuration of a main part of an LSI inspection device suitable for speeding up voltage measurement using an electro-optical effect.

66 is a flowchart showing an example of processing performed by the conversion coefficient determination unit in FIG. 65.

67 is a flowchart illustrating another example of the process performed by the conversion coefficient determining unit in FIG. 65.

FIG. 68 is a flowchart showing yet another example of the processing performed by the conversion coefficient determination unit in FIG. 65.

FIG. 69 is a diagram for explaining a problem of the conventional probe device.

FIG. 70 is a diagram showing a configuration example of a probe device which solves the problem of FIG. 69.

71 is a diagram showing a modification of the probe device of FIG. 70. FIG.

72 is a diagram showing another modification of the probe device of FIG. 70. FIG.

73 is a diagram showing another configuration example of the probe device which solves the problem of FIG. 69. FIG.

FIG. 74 is a diagram showing a configuration example of a probe device suitable for facilitating sample observation and wiring search.

75 is a diagram showing the relationship between the reflectance and the wavelength of the cantilever in FIG. 74.

FIG. 76 is a diagram showing another configuration example of a probe device suitable for facilitating sample observation and wiring search.

77 is a diagram showing the relationship between the reflectance of the cantilever of FIG. 76 and the incident angle of laser light.

FIG. 78 is an explanatory diagram of a force curve.

FIG. 79 is an LSI suitable for determining the probe replacement time.
It is an operation | movement flowchart of an inspection apparatus.

FIG. 80 is a diagram showing a state of positional displacement when the probe is moved to the original point.

FIG. 81 is an explanatory diagram of a force curve for determining the wear amount of the probe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electro-optical crystal (predetermined crystal body) 2 ... Probe substrate (moving body) 3 ... Transparent electrode 4 ... Electrode (connecting means) 5 ... Cantilever 6 ... Fine probe 7 ... Wiring (connecting means) 9 ... Measurement target Fine wiring (sample) 12 ... Sample (semiconductor integrated circuit chip) 17 ... Position detecting light receiver (displacement detecting means) 106, 460, 870 ... Optical microscope (monitoring means) 112 ... First stage 116 ... Opening

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akio Ito 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa, Fujitsu Limited (72) Inventor Kazuyuki Ozaki 1015 Kamedota, Nakahara-ku, Kawasaki, Kanagawa 72) Inventor Shinichi Wakana 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa, Fujitsu Limited

Claims (15)

[Claims] 1. A fine probe having at least a tip made of a conductive material, the probe being attached to one end side, and XY between the sample and the probe.
A cantilever having the other end fixed to a movable body capable of relatively moving in each direction of Z, a means for moving the movable body relative to the sample, and a predetermined crystal body for inducing an electro-optical effect. Connection means for connecting the crystal body and the tip portion of the probe with low electrical resistance, and displacement detection means for detecting displacement generated in the cantilever due to relative proximity of the probe to the sample. A voltage measurement for measuring a voltage at the measurement point by utilizing an electro-optic effect induced in the crystal body when the probe is brought into contact with the measurement point on the sample determined based on the detected displacement A probe device comprising: 2. The probe device according to claim 1, monitor means for observing the vicinity of the wiring to be measured inside the integrated circuit, and the probe device and monitor means are mounted,
Stage means provided so as to be relatively movable with respect to the wiring to be measured, the stage means having an opening for enabling observation by the monitor means and probing by the probe device, An integrated circuit inspection device comprising at least one of a monitor means stage for mounting the monitor means and a probe device stage for mounting the probe device. 3. An anti-vibration table on which the stage means is mounted is further provided, and the stage means is movable in at least XY horizontal directions with respect to the anti-vibration table and has a Z axis as a center. The integrated circuit inspection apparatus according to claim 2, further comprising a rotatable table. 4. The integrated circuit inspection apparatus according to claim 3, further comprising means for fixing a relative positional relationship of the measured integrated circuit with respect to the vibration isolation table. 5. A control computer provided with the probe device according to claim 1, a design database in which information about a mask diagram of an integrated circuit is stored, and a stage control device capable of moving a stage to an arbitrary position. A means for storing alignment information for calculating stage coordinates for displaying a wiring pattern specified by the coordinate system of the mask figure and the coordinates of the mask figure on a microscope image on the computer; An integrated circuit inspection device, comprising: means for acquiring information about a material of a measurement wiring and determining a contact pressure of the probe of the probe device to the wiring according to the type of the material. 6. A stage as a first coarse movement means provided on a frame fixed to a station portion of a tester device for driving an integrated circuit such as an LSI and performing an external test so as to surround the LSI to be tested. Means, a rotary stage provided at a central portion of a moving table of the stage means, and a probe means according to claim 1 provided on the rotary stage for fine movement, and a second coarse movement means. And a monitor means for observing the LSI having the above. 7. A means for capturing and displaying a monitor image of the monitor means as digital data in an image memory, and a means for capturing the displacement amount of the cantilever of the probe device as image signal data and displaying it as at least a one-dimensional image. Control means for positioning the probe of the probe device at a location determined by using the image, and for making electrical contact using the fine movement stage means without cutting and breaking the wiring. The integrated circuit inspection device according to claim 6, wherein 8. The probe device according to claim 1, wherein the optical paths of the laser beam for measuring the displacement of the cantilever and the laser beam for measuring the voltage are both measured from the height of the fine probe at the tip of the cantilever. The probe device is arranged so as to fit within a predetermined height range on the opposite side. 9. The probe device according to claim 1, wherein an electrode connected to the probe is provided on the cantilever substrate, and the electrode is connected to an external voltage control means via a switch means. Probe device. 10. The integrated device comprising: the probe device according to claim 1; and means for controlling the height of the probe with respect to the sample to be constant when the probe horizontally moves. Circuit inspection device. 11. A probe device according to claim 1, means for searching a detailed position on the sample, means for ensuring electrical connection between a measurement point on the sample and the probe, An integrated circuit inspection device comprising: 12. The probe device according to claim 1, a means for applying a known voltage across the crystal body, and a change in the polarization state of light reflected from the crystal body, which is detected. An integrated circuit inspection apparatus comprising: means for calculating a correspondence relationship between a signal and a voltage; and means for converting a detection signal into a voltage value using the correspondence relationship. 13. The probe device according to claim 1, wherein a second substrate for transmitting light is provided on the first substrate made of the crystal, and the second substrate is held to hold the entire probe. A probe device characterized by: 14. The probe device according to claim 1, and monitor means for observing the surface of the integrated circuit to be measured, wherein the cantilever of the probe device has most or all of the observation light from the monitor means. While transmitting
An integrated circuit inspection device having a characteristic of reflecting a part or all of a displacement measuring laser beam. 15. The probe device according to claim 1, and the fineness of the probe device utilizing the change in the control voltage of the fine movement mechanism necessary to give a certain amount of minute displacement to the cantilever portion of the probe device. An integrated circuit inspection device comprising: a means for determining the amount of wear of the probe.