JP4260310B2 - Micro contact type prober - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a probe of a contact-type microcontact prober for circuit testing, position control of the probe, and control of pushing force.
[0002]
[Prior art]
The prior art contact-type circuit probe of the test micro-contact type prober, for example a contact [113] tip on the probe-like cantilever [112] having a metal elasticity, as shown in FIG. 11 1 month attachment, shall have any moving mechanism of the XYZ stage such as the root portion of the probe to to align the probe to the measuring point [111] of the LSI circuit is known.
[0003]
To measure multiple points at the same time, from the measurement terminal arranged at equal intervals side by side the probe as shown in Figure 12 in an array, also known shall obtain a plurality of electrical signals. As a method of position adjustment, after moving in the same field of view housed under moving mechanism such as a stage measurement terminal or the probe of the subject of the objective lens [115] of the long focal the probe and the measurement terminal of the subject In some cases, electrical measurements were made by pressing the probe against the measurement terminal.
[0004]
[Problems to be solved by the invention]
As today, and circuit miniaturization of the subject, the cell size of the memory or the like for inspection come especially equal to or less than 1Myumx1myuemu, wherein the metallic cantilever tension, the processing of the processing and contacts the cantilever It has become difficult.
[0005]
Especially when cell Le is the inspection of memory cells arranged eg in the following equidistant 2~5μm may be aligned with a next a plurality of metal probes are getting I Do difficult spatially.
[0006]
Probes which are mainly used currently, since the probe due to the miniaturization of the cell resulting in sharp Tsu Na, pressing pressure of the subject surface, increases not to appropriate control. For example, by depositing a thin film of ferroelectric under the electrode and memory cell created as FeRAM, in such structure that the decor organic thin film under the electrode as TFT LCD, by increasing the pressing pressure of the probe, It increases the likelihood of damage to the thin film, Ru Ttei such needs control of small pressing force.
[0007]
If parallel solid there beside the multiple probes, unless equipped with tip height of the contactor become apart depth narrowing pressing of the probe, the pressing force is changed for each of the probe, faulty Ya contact by pushing shortage , Film damage due to excessive pressing occurs.
[0008]
Further, when the cell size is particularly 0.5μmx0.5μm below, alignment becomes difficult resolution deficiency in the current optical microscope.
[0009]
[Means for Solving the Problems]
The microcontact prober according to the present invention employs any of the following, preferably a configuration or method in which a plurality (including all) are combined within a range that does not contradict each other.
[0010]
· Conventional rather than metallic probe as, to use a micro probe the silicon by microfabrication processes used in atomic force microscopy (AFM) or the like based material.
[0011]
A probe (cantilever part) is a probe in which a plurality of contacts are created on one cantilever ( measurement cantilever ) for simultaneous measurement of a plurality of analyte measurement terminals . On both sides of the cantilever, preferably with elongated cantilever for Z distance control between the contacts and the object measurement terminal surface.
[0012]
- to adopt the Z distance control cantilever, it controls the movement speed of the contact to a subject measurement terminal, performs control so the amount of deflection of the pressing force measuring cantilever to control is constant.
[0013]
- and for the alignment of the measurement terminal contact, to create the alignment mark in the measurement for the cantilever. By aligning the marks with an optical microscope, the positional relationship between the contacts and the marks was arranged so that each contact would be directly above the measurement terminal.
[0014]
In order to align with a resolution higher than that of an optical microscope, the Z-distance control cantilever at one end is operated in the same manner as the AFM probe, and the cell shape is measured to confirm the cell position . Since the positional relationship between the probe of the cantilever and the cantilever contacts for measurement is known (as determined by initial setting), Ru can align the contacts directly on the cell.
[0015]
・ To make reliable contact, multiple carbon nanotubes are used as contacts.
[0016]
For example, a cantilever for Z distance control is provided with a conductive, those longer than the measuring cantilever is employed.
Example (cantilever part) shown in FIG. 1, a plurality of cantilever [C1] [C2] is created on the same chip [70]. The displacement detection of the cantilever [C1] [C2], M . Tortonese, R.A. C. Barrett, C.D. F. QuateAppl. Phys.Lett.62 (8) as in 1993,834 papers can also be employed self displacement type configuration using the Piezoreji scan Restorative resistance, using an external displacement detector such as an optical lever detector A configuration can also be employed. Cantilever portion is initially assumed that apart distance of several mm from the object measurement terminal. First, the cantilever part is brought close to the subject measurement terminal surface at high speed. First, the long Z-distance control cantilever [C1] comes into contact with the subject measurement terminal surface, thereby generating a deflection signal. Using the generation of this deflection signal as a trigger, the feed speed of Z coarse movement is switched to a low speed. Next, the measurement cantilever [C2] having a contact is brought into contact with the subject measurement terminal surface, and then low-speed feeding is performed until the pushing force enters the set amount range. Here the contact [3] an electrically check the contact of the measuring terminals will check the operation of each analyte row.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Below, we described with reference to the accompanying drawings of embodiments of this invention.
<Configuration of cantilever part>
The structure of the cantilever part shown in FIGS. 1, 2, 3, 4, 5, 6, 7, and 8 will be described. FIGS. 1 and 2 show a cantilever part that uses an external lever detector, for example, to detect the displacement of the cantilever. FIG. 3 shows the outer shape of the cantilever as in FIG. 1, but the displacement detection is embedded inside the cantilever. This is another embodiment using a self-detecting cantilever performed by a piezoresistor [72]. A constant current is passed through the piezoresistor [72], distortion due to the displacement of the cantilever is captured as a change in piezoresistance, and detected as a current change by a bridge circuit. FIG. 4 shows another embodiment of a cantilever portion having three or more cantilevers. The distance control cantilevers are provided at both ends, and a plurality of measurement cantilevers are provided at the center, and each measurement cantilever has a plurality of contacts.
[0018]
Spacing of contacts on neighboring case UGA Nchireba is arranged to be an integral multiple of the cell gap to be measured. Also, the reason why the measuring cantilever is composed of a plurality is that the spring constant of the cantilever is reduced, and when the cantilever part is tilted with respect to the cell to be measured, the pushing amount is adjusted with each cantilever and the pushing force is adjusted. Because.
[0019]
The following have been explained use to FIGS. Cantilever portion is longer Z distance control cantilever lengths [c1] (Length l1: 400~1000μm) and, cantilever for short measurement of the length of the contact [3] [c2] (length l2 : 100-500 μm) are arranged next to each other (the distance between the cantilever probe [40] and the contact [3] is an integer multiple of the cell pitch). The Z distance control cantilever [c1] is coated with a conductive metal such as gold to the needle tip [40] so as to have conductivity.
[0020]
FIG. 2 is a view of the cantilever of FIG. 1 viewed from the lateral direction . When the Z-distance control cantilever [c1] is in contact with the sample surface, the measurement cantilever [c2] is higher than the Z-distance control cantilever [c1] by h <100-300 μm (h = (l1 -l2) sinθ; l1: length of the cantilever of the Z distance control, l2: cantilever length for measurement, theta: a state of floating from the cantilever mounting angle) by sample surface.
Z distance control cantilever [c1], the tip radius of about 100-200 nm, the spring constant is 0.01~0.1N / m. Since the spring constant is soft, damage to the cantilever and damage to the sample surface are small even when the Z-distance control cantilever contacts the sample surface at high speed.
[0021]
Figure 5 shows a detail of the contact [3] a cantilever for measurement, including the arrangement and configuration of [c2]. The contact [3] is a protrusion having a height of about 10 μm, the tip radius is 100-200 nm, and the metal coating [31] is applied only to this protrusion. This metal coating [31] is wired [50] to the cantilever base [70] , and is connected to the connecting pad [60] at the base [70] . An external electrical tester ([12] in FIG. 9) is connected to the pad [60] , and various test signals can be applied between the contact [3] and the measurement terminal.
[0022]
As shown in the plan view of FIG. 6, the insulation between each contact [3] [75] it is separated by silicon oxide. The further opposite side of the contact [3] surfaces and contact [3], separated by a silicon oxide film [75] as shown in the sectional view of FIG. 7, on the opposite side of the contact [3] The cantilever surface is coated with metal [76] and can be connected to earth potential to serve as a shield electrode.
The interval between adjacent contacts [3] is made equal to the cell pitch to be inspected or an integer multiple of the pitch.
[0023]
FIG. 8 shows an example of another embodiment in which a plurality of carbon nanotubes [33] are formed as a contact [3] . In this case , the contact [3] is made by patterning a 1-3 μm square iron-based catalyst on the base [71] of the silicon cantilever [32], and in a hydrocarbon atmosphere such as ethane at 700 to 1000 ° C. When the phase growth is performed, a large number of carbon nanotubes having a uniform length perpendicular to the substrate grow from the places patterned with the iron-based catalyst. The carbon nanotubes are conductive, and the iron-based catalyst at the base and the cantilever base [70] may be wired with a thin metal wire [50], and the insulation [75] between the contacts may be separated by silicon oxide. When carbon nanotubes are used as the contact [3] , a voltage can be applied stably without the coating material popping out by field evaporation, compared to a metal-coated contact. In addition, the carbon nanotubes themselves are elastic and robust so that they can withstand multiple contact.
[0024]
<Main equipment configuration>
The configuration of the main part of the apparatus will be described with reference to FIG. An XYZ scanning scanner [2] is fixed to a moving mechanism (Z coarse movement mechanism) [1] that moves the cantilever close to the sample, and a cantilever base [70] is attached to the tip of the scanner. In addition, the subject [6] is electrically connected to the sample stage [5] by the sample stage contact [4], and is arranged to face the cantilever portion. In FIG. 9, cantilevers [c1] and [c2] are depicted as self-detecting cantilevers. The displacement signal of the measurement cantilever [c2] shown in FIG. 9 is amplified by the preamplifier [7] and input to the Z servo system [8]. The output signal is amplified by the Z-scanning controller [11]. As a result, the Z-axis of the XYZ scanning scanner [2] expands and contracts, so that the deflection of the measuring cantilever is constant, between the contact [3] and the measuring terminal The distance of [6] is controlled. On the other hand, the signal from the Z distance control cantilever [c1] shown in FIG. 9 is similarly amplified by the preamplifier [7] and input to [9] to the Z coarse motion controller and used as a control signal for the Z coarse motion mechanism [1]. It is used. The Z coarse movement mechanism is mainly composed of a mechanical system such as a differential screw and a reduction lever, and can move about mm in steps of 0.1 to 0.05 μm. Here, from a few mm on the measurement terminal surface to 0.1-0.3 mm, the Z coarse movement mechanical mechanism [1] is controlled to send at high speed, and the remaining 0.1-0.3 mm or less is sent at low speed.
[0025]
<Distance control operation and contact pushing force adjustment>
Then as FIG. 1, the operation of the Z coarse with the time chart of FIG. 10. Initially, the cantilever part is several mm away from the sample surface. When the Z coarse motion mechanism [1] is moved at high speed and the Z distance control cantilever [c1] contacts the sample surface as shown in FIG. 1 [FIG. 10: t0], the Z distance control cantilever is the measurement terminal. The displacement signal of the cantilever changes due to the force from the surface. This signal is input to the Z coarse controller [9], and the Z coarse mechanism [1] is switched to low speed feed. At this time [FIG. 10: t0], the measurement cantilever [c2] floats from the sample surface by approximately h. Next, at a low speed, approximately h> 100-300 μm (h: the difference in height between the Z-distance control cantilever and the measurement cantilever from the subject surface) is brought into contact with the measurement cantilever [c2]. [FIG. 10: t1] Thereafter, the contactor is pushed into the subject measurement terminal surface by Δh [FIG. 10: t2]. At this time , the measurement cantilever receives a force from the measurement terminal surface and the displacement signal of the cantilever changes. The pressing force is obtained by multiplying the spring constant of the measuring cantilever by Δh (cantilever pressing depth), and this amount can be controlled by a pressing force setting signal indicated by asterisks in FIG.
[0026]
When using a cantilever portion having a plurality of measurement cantilever [c2] shown in FIG. 4, respectively cantilevers [c1] the Z distance control across may take OR signal of [c1 ']. Even if Toritsui inclined cantilever base [70], either Z distance control cantilever signal closer to the sample surface can you to use as a signal Z rough movement controller [9].
[0027]
After contact with the measurement terminal of the subject and adjustment of the pressing force (after t2), various test signals are applied between the contact [3] and the measurement terminal from the external electrical test machine [12 ], and the electrical Evaluate.
[0028]
<Alignment with measurement cell>
Here, the description will be made on the assumption that the subject is a two-dimensional array of spatially similar shapes such as memory cells.
The dimensions of each part of the cantilever for cell measurement are made as follows. The contact [3] on the measurement cantilever is arranged at equal intervals with the cell pitch or an integer multiple of the pitch, and the needle tip [40] of the Z distance control cantilever [c1 ] and the contact [3] The interval is made to be an integral multiple of the cell. Also, on the back or side of the measuring cantilever [c2], an alignment mark [Fig. 6:76] (size 1 μm x 1 μm or more) having a fixed positional relationship with the contact [3] is created and aligned with a microscope. Use as a guide for
[0029]
Micro-alignment with the cell is performed by applying a voltage to the XY axis of the XYZ scanning scanner while observing with an optical microscope so that the contact [3 ] on the measurement cantilever [c2] is directly above the cell. Make fine adjustments to the position. If the cell is too small to be seen with an optical microscope, the Z distance control cantilever [c1] is scanned in XY, and the Z scanner is controlled so that the displacement of this cantilever [c1] is constant. The cell shape can be obtained by performing the same operation. Based on the shape of the cell, the positional relationship between the contact and the cell is obtained, and alignment is possible.
[0030]
Naturally, the present invention cannot be construed as being limited to the above-described embodiment, but is construed based on the philosophy and spirit that flows in this specification and the like. Accordingly, the present invention naturally includes the following technical ideas.
[0031]
(1) As a probe for electrical testing, it has a conductive contact and a cantilever (cantilever), and controls the object surface measurement terminal and the pushing force of the contact from the deflection signal of the same or adjacent cantilever. In a microcontact prober that confirms contact, then applies an electrical signal to the circuit of the subject through the contact, and confirms the operation of the LSI circuit, and has a plurality of cantilevers as the probe for electrical testing, A micro-contact prober characterized in that one or more contacts are arranged next to each other on the same cantilever .
[0032]
Micro contact type prober
(2) The technology is characterized in that the contacts on the cantilever are conductive, the individual contacts are insulated, and the distance between the individual contacts is equal to or equal to the pitch of the cell to be measured. Micro-contact prober with ideal idea (1).
[0033]
(3) A fine contact prober according to the technical idea (1), wherein carbon nano-tube is used as a material of the contact.
[0034]
(4) A microcontact prober according to the technical idea (1), wherein the insulation between the contacts is performed by the silicon oxide layer of the SOI substrate.
[0035]
(5) The microcontact prober of the technical idea (1), wherein the contact surface and the back surface of the cantilever are insulated and the back surface is coated with a metal film.
[0036]
(6) A small cantilever made of silicon or silicon nitride has a plurality of conductive contacts for electrical measurement, and a measurement cantilever for extracting electrical signals from the contacts by wiring and a subject on both sides A microcontact prober with a probe that has a cantilever for controlling the distance to the surface.
[0037]
(7) A microcontact prober according to the technical idea (6) having a microscope guide mark in a fixed positional relationship with the contact on the side surface of the measurement cantilever or on the opposite side of the contact.
[0038]
(8) A microcontact prober according to the technical idea (1) or the technical idea (6), comprising a piezo scanner operating in the XY directions for controlling the micro position of the probe.
[0039]
(9) The microcontact prober according to the technical idea (1) or (2), which has a piezo scanner that operates in the Z direction for controlling the pushing force of the probe.
[0040]
【The invention's effect】
According to the present invention, electrical evaluation can be performed by directly contacting each miniaturized cell using the micro probe as described above. In addition, since the pressing force is controlled, electrical evaluation can be performed without causing contact failure due to insufficient pressing or damage to the thin film of the cell due to excessive pressing.
[0041]
When the resolution of the optical microscope is insufficient, the cell shape can be obtained by the same operation as the AFM, and the contact can be accurately positioned on the cell.
[Brief description of the drawings]
FIG. 1 is a perspective view of an external detector probe (cantilever part).
FIG. 2 is a side view of an external detector probe (cantilever part).
FIG. 3 is a schematic diagram of a probe (cantilever part) portion of a micro-micro contact prober. (A) is a perspective view of a probe using a self-detecting cantilever, and (b) is a cross-sectional view along the line AA ′ in (a).
FIG. 4 is a schematic diagram of a probe having three or more cantilevers.
FIG. 5 is a schematic diagram of a detailed description of a probe. (A) is a perspective view of a measurement cantilever, (b) is a view seen from the A direction in (a).
FIG. 6 is a plan view of a measurement cantilever.
FIG. 7 is a cross-sectional view of a measurement cantilever.
FIG. 8 is a schematic diagram of a probe, a position control mechanism (XYZ scanning scanner), and a control system of the probe of the micro / micro contact prober apparatus. (A) is a perspective view of a measurement cantilever using a carbon nanotube as a contact, and (b) is a view as seen from the A direction in (a).
FIG. 9 is a schematic view of a microcontact type prober apparatus according to the present invention.
FIG. 10 is a time cheat when the probe is approaching. It is a time cheat of operation.
FIG. 11 is a schematic diagram of a probe of a conventional microcontact prober.
FIG. 12 is a schematic diagram of a microcontact prober in which probes are arranged in a conventional array type.
[Explanation of symbols]
1 Z coarse movement mechanism 2 XYZ fine movement scanner 3 Probe (cantilever part)
4 Contact on the sample table 5 Sample table 6 Subject 7 Preamplifier 8 Z servo system 9 Z coarse controller 10 XY scan controller 11 Z scan controller 12 External electric circuit 20 Control computer ☆ Marking force setting signal

Claims (10)

A cantilever base,
One or more measurement cantilevers supported by the cantilever base, each of the one or more measurement cantilevers has a plurality of contacts, and each contact is wired to transmit a signal. A contact with a tip radius of 100 to 200 nm, and one or more measuring cantilevers for conducting an electrical test using each contact;
A Z-distance control cantilever that is supported by the cantilever base and has an arm portion longer than the measurement cantilever, and for acquiring information in the height direction with the subject measurement terminal surface;
A Z coarse movement mechanism that enables movement of the cantilever in the Z-axis direction ,
Using said Z distance control cantilever acquires information in the height direction of the subject measurement terminal surface, and based on the relevant information, for the measurement of the cantilever by controlling movement by the Z coarse positioner A microcontact prober characterized in that a contact provided on a cantilever is brought into contact with the subject measurement terminal surface, and an electrical test is performed with the measurement cantilever in that state . A microcontact prober according to claim 1,
The Z distance control cantilever is brought close to the subject measurement terminal surface at high speed,
When the Z-distance control cantilever contacts the subject measurement terminal surface, a deflection signal is generated based on information from the subject measurement terminal surface, and the deflection signal is used as a trigger to slow down the approach to the subject measurement terminal surface. switching,
The measurement cantilever is brought close to the subject measurement terminal surface at a low speed, the contactor is brought into contact with the subject measurement terminal surface, and a pushing force is applied to the contact portion by further pushing.
A micro-contact prober that performs low-speed feeding until the pushing force enters a set amount range .   3. The microcontact prober according to claim 1, wherein each contact provided on the measurement cantilever is insulated from each other including a wire connected to each contact. 4.   4. A microcontact prober according to claim 3, wherein the insulation between the contacts is taken by the silicon oxide layer of the SOI substrate.   The micro contact prober according to any one of claims 1 to 4, wherein the measurement cantilever has contacts arranged at an interval substantially equal to an arrangement interval of each cell to be measured.   The microcontact prober according to any one of claims 1 to 4, wherein the measurement cantilever has contacts arranged at an interval that is an integral multiple of the arrangement interval of each cell to be measured.   The microcontact prober according to any one of claims 1 to 6, wherein the contact is made of carbon nanotubes.   The micro contact prober according to any one of claims 1 to 7, wherein the measurement cantilever has a surface on which a contact is provided and a back surface insulated from each other, and the back surface is coated with a metal film. .   The measurement cantilever has a guide mark for controlling the position of the measurement cantilever with respect to the subject measurement terminal surface using an optical microscope on at least one of the side surface and the back surface of the surface provided with the contact. The microcontact type prober according to any one of claims 1 to 8.   10. The microcontact according to claim 1, comprising at least one of a piezo scanner operating in the XY direction and a piezo scanner operating in the Z direction for controlling the micro position of the measurement cantilever. Expression prober.

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