CN101241153B - Thin film electric resistivity automatic measuring instruments - Google Patents

Abstract

The present invention provides an automatic measuring instrument for films resistivity comprising of four probes, constant current source, voltage and current measurement module, controller and circuit switch module. Controller, constant current source, circuit switch module and voltage and current measurement module are connected in turn to form loop, the other two interfaces of circuit switch module are connected controller and four probes respectively, circuit switch module chooses two probes of four probes as current probes and others as voltage probes according to circuit switch signal of controller, constant current source produce constant current according to current control signal from controller and make the constant current pass through the current probes and voltage probes to induce electric potential difference, voltage and current measurement module measures constant current and electric potential difference and transmits them to controller to calculate resistivity. The present invention avoids changing circuit joint and probe position adjustment by manual manner, and enhances the speed and precision of measurement of films resistivity.

Description

Thin film electric resistivity automatic measuring instruments

Technical field

The present invention relates to the measuring technique of electronic material resistivity, particularly relate to the measuring technique of membraneous material resistivity.

Background technology

In electronic material research, resistivity is the important parameter of assessment material performance.For example in the research of nano wave-absorbing material, the purpose of its material design is to widen absorption band, the quality of absorbing property and the storage of material electric field energy are closely related with the loss size, and the complex permittivity in the material basic parameter is used to reflect this storage of material electric field energy and loss size just, and the accurate measurement of resistivity is the important step in the design of absorbing material as can be seen.

Measuring the general four probe method of using for material resistance finishes.This method requires the smooth and approximates infinity of print of measurement, DC current is fed sample by two probes in the four point probe, measure the electric potential difference of responding between other two probes, according to current value, the geometric parameter of potential difference values and material calculates resistivity value.General four point probe resistivity measurement equipment is to be the design of solid semiconductor Materials Measurement, and not exclusively is fit to the measurement of membraneous material resistivity.Membraneous material has its uniqueness with respect to the solid semiconductor material, be embodied in (1) film and generally adopt technology making such as sputter coating, himself shape is restricted, and four probe method requires the smooth and approximates infinity of print, therefore using traditional four-probe measurement MEASUREMENTS OF THIN resistivity of material need introduce a large amount of corrections, perfect correction system is very complicated, and common measuring system can not be finished; (2) resistivity of film is generally very little, needs higher voltage measurement precision and Current Control precision; (3) very thin thickness of film, sample is very easy with the manual measurement system time is scratched by probe pinpoint.

At the feature of film sample, change theoretical model, on the basis of traditional four probe method, designed two electrical measurement combined methods.Two electrical measurement combined methods are revised four point probe basic theories model according to the characteristics of membraneous material; Need switch current, voltage probe under this method, different current/voltage probes is selected corresponding three kinds of different circuit connecting modes, and three kinds of connected modes constitute three kinds of integrated modes in twos; By mathematic(al) manipulation, under every kind of pattern, can derive resistivity according to the measurement result that two kinds of connected modes obtain.The such resistivity value of theoretical proof is not influenced by size effect, for desirable print, resistivity value under three kinds of patterns should be consistent, and in the actual measurement, three measurement results necessarily have deviation, and deviation is mainly derived from two aspects: the first, and actual print is not evenly absolute, and the measured zone of each pattern difference slightly can be studied the print homogeneity by contrasting three measurement results; Second, the error of measuring equipment itself, owing to be high-precision measuring process, the influence of instrument itself can significantly be reflected in the measurement result, such as always having gap under the resistivity value under certain pattern and other patterns, must be probe or the circuit existing problems relevant with this pattern.Can reduce the error of this two aspect by the method for averaging, obtain measurement result more accurately.

The film resiativity measurement mechanism of two electrical measurement combined methods has appearred using in prior art at present, but these devices need to regulate by manual change circuit connecting mode and probe location in measuring process, measuring speed is slow, precision is low, and the control accuracy of constant current source and current-voltage measurement precision also can't guarantee under the situation of circuit structure frequent variations; Data handling procedure is used chip microcontroller more, has limited to the fitting function that two electrical measurement combined methods relate to and the computational accuracy of correction function.

Summary of the invention

The purpose of this invention is to provide a kind of thin film electric resistivity automatic measuring instruments, this device has avoided manual mode to change the circuit connection and probe location is regulated, and has improved speed and precision that film resiativity is measured.

The invention provides a kind of thin film electric resistivity automatic measuring instruments, comprise four point probe 6, constant current source (4) and voltage and current measurement module 5, it is characterized in that, also comprise controller 1 and circuit handover module 2, controller 1, constant current source 4, circuit handover module 2 and voltage and current measurement module 5 connect and compose the loop successively, the other two-port of circuit handover module 2 connects controller 1 and four point probe 6 respectively, circuit handover module 2 selects two probes in the four point probe 6 as current probe according to the circuit switching signal of coming self-controller 1, other two probes are as voltage probe, constant current source 4 produces steady current according to the current controling signal that comes self-controller 1, make it pass through current probe, voltage probe induced electricity potential difference, voltage and current measurement module 5 measures steady current and electric potential difference sends controller 1 to, controller 1 calculated resistance rate.

As a further improvement on the present invention, also be connected to probe location regulator 3 between described controller 1 and the four point probe 6, be used for adjusting the relative position of four point probe and sample according to the position control signal of controller 1.

The present invention is the thin film electric resistivity automatic measuring instruments according to two electrical measurement combined method designs, contain the circuit handover module in the device, relay under the control of computing machine in the circuit handover module disconnects with current/voltage connection terminal and four point probe or is connected, thereby automatic switch-over circuit connected mode, probe current and probe potential that the voltage and current measurement module records under each connected mode are poor, and pass to controller and calculate to calculate the resistivity of this film sample.Entire work process is to finish automatically under the control of computing machine, and the speed of comparing existing measuring instrument measurement is faster higher with measuring accuracy.

Description of drawings

Fig. 1 is a structural drawing of the present invention;

Fig. 2 is the probe arrangement mode under three kinds of patterns in two electrical measurement combined methods;

Fig. 3 is three kinds of circuit connecting mode synoptic diagram;

Fig. 4 is a circuit handover module structural drawing;

Fig. 5 is probe location controller structure figure;

Fig. 6 is software realization flow figure of the present invention;

Fig. 7 takes multiple measurements the result schematic diagram that obtains;

Fig. 8 is the selection of different test positions;

The comparison diagram as a result that Fig. 9 obtains in the diverse location test for distinct methods.

Embodiment

Describe the present invention in detail below in conjunction with drawings and Examples.

Design basis of the present invention is two electrical measurement combined methods, and two electrical measurement combined methods require measuring equipment to switch in three kinds of circuit connecting modes dynamically in measuring process, and Fig. 3 has provided the circuit connecting mode synoptic diagram, 1., 2., 3. and 4. is the probe sequence number.

Circuit connecting mode shown in Fig. 3 a represents that 1. and 2. probe is current probe, 3. and 4. probe is voltage probe, circuit connecting mode shown in Fig. 3 b represents that 1. and 4. probe is current probe, 3. and 2. probe is voltage probe, circuit connecting mode shown in Fig. 3 c represents that 1. and 3. probe is current probe, and 2. and 4. probe is voltage probe.

Three kinds of connected modes constitute three kinds of patterns in twos, and by mathematic(al) manipulation, the measurement result that obtains according to two kinds of connected modes under every kind of pattern derives resistivity.Pattern 1 shown in the circuit connecting mode corresponding diagram 2a shown in Fig. 3 b and Fig. 3 c, the pattern 2 shown in the circuit connecting mode corresponding diagram 2b shown in Fig. 3 a and Fig. 3 b, the mode 3 shown in the circuit connecting mode corresponding diagram 2c shown in Fig. 3 a and Fig. 3 c.V ₂₄Electric potential difference between the voltage probe of presentation graphs 3b correspondence, V ₂₃Electric potential difference, V between the voltage probe of presentation graphs 3c correspondence ₃₄Electric potential difference between the voltage probe of presentation graphs 3a correspondence.I ₁₂The steady current that the current probe of presentation graphs 3a correspondence passes through, I ₁₃The steady current that the current probe of presentation graphs 3c correspondence passes through, I ₁₄The steady current that the current probe of presentation graphs 3a correspondence passes through.

Just be how to control the switching of three kinds of circuit connecting modes shown in Figure 3 based on the crucial part of the measurement mechanism of two electrical measurement combined methods.

As shown in Figure 1, the present invention includes controller 1, circuit handover module 2, four point probe 6, constant current source 4, voltage and current measurement module 5.The course of work is: at first controller 1 to circuit handover module 2 transtation mission circuit switching signals to determine circuit connecting mode, then controller 1 sends current controling signal to constant current source 4, constant current source 4 is applied to the electric current of appointment on the current probe of four point probe 6 by circuit handover module 2, build measurement environment, voltage probe meeting this moment induced electricity potential difference, potential difference on the voltage and current measurement module 5 measuring voltage probes and the current value on the current probe, and measurement result passed to controller 1; Controller 1 recording voltage value and current value, to circuit handover module 2 transtation mission circuit switching signals, voltage and current measurement module 5 is measured under new circuit connecting mode once more, and voltage and current measurement module 5 is measured once more; After the measurement result that obtains under whole three kinds of connected modes, controller 1 cuts out constant current source 4, and reset circuit handover module 2, calculates the value of resistivity at last according to three groups of measurement results.

As core of the present invention, circuit handover module 2 comprises current/voltage connection terminal 222 and circuit handover module 21.Current/voltage connection terminal 222 comprises current terminal I _InAnd I _Out, voltage terminal V+ and V-; Circuit handover module 21 comprises four relays.Concrete connected mode is referring to table 1 and Fig. 4, current terminal I _InFirst probe that connects constant current source 4 and four point probe 3.Current terminal I _OutThe common port and the voltage and current measurement module 5 that connect constant current source 4, relay I; The common port of relay I connects current terminal I _Out, normally opened contact connects the common port of relay II, and normally closed contact connects second probe of described four point probe 6; The common port of relay II connects the normally opened contact of relay I, and normally closed contact connects the 3rd probe of four point probe 6, and normally opened contact connects the four point probe of described four point probe 3; The common port of relay III connects voltage terminal V+, and normally closed contact connects the 3rd probe of four point probe 3, and normally opened contact connects second probe of described four point probe 6; The common port of relay IV connects voltage terminal V-, and normally closed contact connects four point probe, and normally opened contact connects the 3rd probe of described four point probe 3; Voltage terminal V+ connects the common port of described voltage and current measurement module 5 and relay III; Voltage terminal V-connects the common port of described voltage and current measurement module 5 and relay IV.

The concrete connected mode of table 1 circuit handover module

The changing method reference table 2 of three kinds of circuit connecting modes, by the common port and the normally closed contact of four relays, the switching of three kinds of circuit connecting modes of the closed and disconnected of normally opened contact control,

Table 2 circuit transfer relay maneuver

In the present embodiment, voltage and current measurement module 5 adopts digital multimeter.In order to adapt to the metering system of digital multimeter, digital multimeter connection terminal group 221 and relay V in circuit handover module 2, have also been set up.In digital multimeter connection terminal group, second connection terminal is a common port, constitute voltage measurement port and current measurement port with the first, the 3rd terminal respectively, first connection terminal connects voltage terminal V+, second connection terminal connects the normally opened contact of voltage terminal V-and relay V, and the 3rd connection terminal connects normally closed contact and the constant current source 4 of relay V.

In measuring process, need constantly to regulate the position of the relative sample of probe, for fear of manual operation print is produced damage, system realizes by software mode.The present invention increases probe location regulator 6, is used to come the position control signal adjustment four point probe of self-controller 1 and the relative position of sample.Probe location regulator 3 comprises vertical control assembly, horizontal control assembly, Spin Control parts and sample tray, vertical control assembly is used to control the upright position of four point probe with respect to pallet, horizontal control assembly is used to control the horizontal level of sample tray with respect to four point probe, the pallet middle part is provided with the disk 39 that is used for load sample, and Spin Control unit control disk is around its central horizontal rotation.

As shown in Figure 5, vertical control assembly comprises column 311, column 311 sidewalls are fixed with vertical stepper motor 31, vertical stepper motor 31 connects vertical spiral shell rod 33 tops, be with perpendicular displacement slide block 32 in vertical spiral shell rod 33 outers, upright position control step motor 31 makes perpendicular displacement slide block 32 move up and down along vertical spiral shell rod 33 by controlling vertical spiral shell rod 33 rotations, and four point probe is fixed in perpendicular displacement slide block 32 bottoms;

Horizontal control assembly comprises horizontal stepper motor 34, horizontal stepper motor 34 joins with horizontal spiral shell rod 35 1 ends, horizontal spiral shell rod 35 outers are with horizontal shift slide block 36, and horizontal stepper motor 34 makes horizontal shift slide block 36 move horizontally along horizontal spiral shell rod 35 by 35 rotations of controlling level spiral shell rod; Horizontal shift slide block 36 sidewalls are connected with described sample tray 37, and along with moving horizontally of sample tray horizontal level slide block 36, sample tray 37 also moves as respective horizontal;

The Spin Control parts comprise the rotating stepper motor 38 that joins by gear and described disk 39.

Measurement function realizes that by operation software control on computers software flow pattern as shown in Figure 6.Measurement can be at manual measurement and is measured under two kinds of patterns automatically and carry out.The user can freely control probe location under the manual mode, selects measurement pattern; Under the automatic mode, computing machine sends position control signal, and probe location control module 3 control step motors are to regulate probe location.

After controller 1 obtains three groups of electric current and voltages of three kinds of connection mode correspondences, beginning calculated resistance rate, detailed process is:

The electric current and voltage value that obtains under three kinds of connected modes is converted to measured value:

${\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="S2008100470317E00021.png,S2008100470317E00052.png"\; state="\{\{state\}\}">R</figure-callout>}}_1=\frac{V_{43}}{I_{12}}$ ${\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="S2008100470317E00021.png,S2008100470317E00053.png"\; state="\{\{state\}\}">R</figure-callout>}}_2=\frac{V_{23}}{I_{14}}$ ${\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="S2008100470317E00021.png,S2008100470317E00053.png"\; state="\{\{state\}\}">R</figure-callout>}}_3=\frac{V_{24}}{I_{13}}$

f ₁, f ₂, f ₃Be fitting function, itself and measured value satisfy formula (1)～(3),

$\frac{R_2}{R_3}=\frac{\ln 2}{f_1}+\mathrm{arsh}\left[2^{-(\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100470317E00021.png,S2008100470317E00052.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}+1)}\right]/\frac{\ln 2}{f_1}-\mathrm{arsh}\left[2^{-(\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100470317E00021.png,S2008100470317E00052.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}+1)}\right]---\left(1\right)$

$\frac{R_1}{R_2}=\frac{\ln 2}{f_2}-\mathrm{arsh}\left[2^{(\frac{1}{f_2}-1)}\right]/\frac{\ln 2}{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="S2008100470317E00021.png,S2008100470317E00053.png"\; state="\{\{state\}\}">f</figure-callout>}}_2}+\mathrm{arsh}\left[2^{(\frac{1}{f_2}-1)}\right]---\left(2\right)$

$\frac{R_3}{R_1}=\frac{\ln 2}{{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="S2008100470317E00021.png,S2008100470317E00053.png"\; state="\{\{state\}\}">f</figure-callout>}}_3}+\mathrm{arsh}\left[2^{(\frac{1}{f_3}-1)}\right]/-\frac{\ln 2}{{\mathrm{<figure-callout\; id="3"\; label="f"\; filenames="S2008100470317E00021.png,S2008100470317E00053.png"\; state="\{\{state\}\}">f</figure-callout>}}_3}+\mathrm{arsh}\left[2^{(\frac{1}{f_3}-1)}\right]---\left(3\right)$

With measured value R ₁, R ₂And R ₃Fitting function f is determined in substitution formula (1)～(3) ₁, f ₂, f ₃

Two electrical measurement combined methods can not be eliminated the influence of thickness of sample to resistivity measurement.Obtain electric potential difference V according to formula (4)～(6) according to the thin layer principle ₂₃, V ₃₄, V ₂₄Thickness correction function f ₄, f ₅, f ₆N value in the expression formula is big more more near ideal state

$f_4(W/S)=\frac{2(S/W)\ln 2}{F_{\mathrm{sn}}(W/S)}$ Wherein $F_{\mathrm{sn}}\left(\frac{W}{S}\right)=1+4\underset{n=1}{\overset{1}{\mathrm{\&Sigma;}}}(\frac{1}{\sqrt{{(2\mathrm{nW}/S)}^2+1}}-\frac{1}{\sqrt{{\left(2\mathrm{nW}\right)}^2+4}})---\left(4\right)$

$f_5(W/S)=\frac{3(S/W)\ln (4/3)}{F_{\mathrm{su}}(W/S)}$ Wherein $F_{\mathrm{su}}\left(\frac{W}{S}\right)=1+6\underset{n=1}{\overset{1}{\mathrm{\&Sigma;}}}(\frac{1}{\sqrt{{(2\mathrm{nW}/S)}^2+9}}+\frac{1}{\sqrt{{(2\mathrm{nW}/S)}^2+1}}-\frac{2}{\sqrt{{\left(2\mathrm{nW}\right)}^2+4}}---\left(5\right)$

$f_6(W/S)=\frac{(3/2)(S/W)\ln 3}{F_{\mathrm{per}}(W/S)}$ Wherein $F_{\mathrm{per}}\left(\frac{W}{S}\right)=1+3\underset{n=1}{\overset{1}{\mathrm{\&Sigma;}}}(\frac{1}{\sqrt{{(2\mathrm{nW}/S)}^2+1}}-\frac{1}{\sqrt{{\left(2\mathrm{nW}\right)}^2+9}})---\left(6\right)$

Calculate resistivity corresponding under each pattern according to formula (7)～(8):

Pattern 1 $\mathrm{\&rho;}=\frac{\mathrm{\&pi;}}{\mathrm{<figure-callout\; id="2"\; label="ln"\; filenames="S2008100470317E00021.png,S2008100470317E00053.png"\; state="\{\{state\}\}">ln</figure-callout>}2}\&times;\frac{V_{23}{f}_4\left(\mathrm{\&alpha;}\right)+V_{24}{f}_6\left(\mathrm{\&alpha;}\right)}{I}\&times;f_1\left(\frac{V_{23}{f}_4\left(\mathrm{\&alpha;}\right)}{V_{24}{f}_6\left(\mathrm{\&alpha;}\right)}\right)W---\left(7\right)$

Pattern 2 $\mathrm{\&rho;}=\frac{\mathrm{\&pi;}}{\mathrm{<figure-callout\; id="2"\; label="ln"\; filenames="S2008100470317E00021.png,S2008100470317E00053.png"\; state="\{\{state\}\}">ln</figure-callout>}2}\&times;\frac{V_{23}{f}_4\left(\mathrm{\&alpha;}\right)+V_{34}{f}_5\left(\mathrm{\&alpha;}\right)}{I}\&times;{\left(\frac{V_{34}{f}_5\left(\mathrm{\&alpha;}\right)}{V_{23}{f}_4\left(\mathrm{\&alpha;}\right)}\right)}^W---\left(8\right)$

Mode 3 $\mathrm{\&rho;}=\frac{\mathrm{\&pi;}}{\mathrm{<figure-callout\; id="2"\; label="ln"\; filenames="S2008100470317E00021.png,S2008100470317E00053.png"\; state="\{\{state\}\}">ln</figure-callout>}2}\&times;\frac{V_{24}{f}_{64}\left(\mathrm{\&alpha;}\right)-V_{34}{f}_5\left(\mathrm{\&alpha;}\right)}{I}\&times;f_3\left(\frac{V_{24}{f}_6\left(\mathrm{\&alpha;}\right)}{V_{34}{f}_5\left(\mathrm{\&alpha;}\right)}\right)W---\left(9\right)$

α=W/S wherein

At last the resistivity of trying to achieve under three kinds of patterns is averaged, obtain final resistivity.

The present invention can be directly used in the measurement of film sample resistivity, introduces its operational effect with the example that is measured as of thin magnetic film resistivity.

Thin magnetic film adopts the method for sputter coating to make, and film is very thin and sample size is limited, is very easy to film is scratched when the traditional four point probe equipment of application carries out resistivity measurement, and measurement can't be carried out; And can not measure according to desirable print, need to introduce complicated size correction.Adopt two electrical measurement combined methods can improve measuring accuracy, use the measurement result that obtains that the present invention can be fast automatic this sample.

Be the verification system measuring stability, print has been carried out repeatedly measuring.Fig. 7 shows, and to be system carry out the result that measures for 20 times continuously to a slice print, and as can be seen, the result that each time measures is consistent substantially, and system stability is good.From measurement result as can be seen, the resistivity that obtains under three kinds of patterns in two electrical measurement combined methods is very approaching; The resistivity value that the Perloff method obtains and two electrical measurement combined method are also more approaching; And the resistivity value that traditional method obtains is less than the value that obtains with additive method, and big gap is arranged.These can obtain reasonable dismissal from theory.

Be of the influence of confirmatory measurement position, the existing resistivity value that relatively obtains in the different measuring position to measurement result.Testing used print is strip, gets at the center and peripheral place and a little tests as shown in Figure 8, and probe sequence is parallel to minor face; Get some the arbitrfary point on print, the not parallel any one side of probe.Test findings is as shown in Figure 9: it is little that influence is sent out to two electrical measurements combinations in the change measuring position; And the resistivity value that traditional method and Perloff method obtain has very big variation.As seen two electrical measurement combined methods are compared other measuring methods has stronger adaptability to the print size.

Claims (6)

1. thin film electric resistivity automatic measuring instruments, comprise four point probe (6), constant current source (4) and voltage and current measurement module (5), it is characterized in that, also comprise controller (1) and circuit handover module (2), controller (1), constant current source (4), circuit handover module (2) and voltage and current measurement module (5) connect and compose the loop successively, the other two-port of circuit handover module (2) connects controller (1) and four point probe (6) respectively, circuit handover module (2) selects two probes in the four point probe (6) as current probe according to the circuit switching signal of coming self-controller (1), other two probes are as voltage probe, constant current source (4) produces steady current according to the current controling signal that comes self-controller (1), make it pass through current probe, voltage probe induced electricity potential difference, voltage and current measurement module (5) is measured steady current and electric potential difference sends controller (1) to, controller (1) calculated resistance rate;

The circuit handover module (21) that described circuit handover module (2) comprises current/voltage connection terminal (222) and joins with it, current/voltage connection terminal (222) comprises current terminal I _InAnd I _Out, voltage terminal V+ and V-, circuit handover module (21) comprises first, second, third, fourth relay,

Current terminal I _InFirst probe that connects described constant current source (4) and described four point probe (6);

Current terminal I _OutThe common port and the voltage and current measurement module (5) that connect described constant current source (4), first relay;

The common port of first relay connects current terminal I _Out, normally opened contact connects the common port of second relay, and normally closed contact connects second probe of described four point probe (6);

The common port of second relay connects the normally opened contact of first relay, and normally closed contact connects the 3rd probe, and normally opened contact connects the four point probe of described four point probe (6);

The common port of the 3rd relay connects voltage terminal V+, and normally closed contact connects the 3rd probe, and normally opened contact connects second probe of described four point probe (6);

The common port of the 4th relay connects voltage terminal V-, and normally closed contact connects four point probe, and normally opened contact connects the 3rd probe of described four point probe (6);

Voltage terminal V+ connects the common port of described voltage and current measurement module (5) and the 3rd relay;

Voltage terminal V-connects the common port of described voltage and current measurement module (5) and the 4th relay;

The closed and disconnected of the common port of four relays and normally closed contact, normally opened contact is combined to form three kinds of circuit connecting modes, and is specific as follows:

First connected mode: the common port of four relays connects normally closed contact;

Second connected mode: the common port of four relays connects normally opened contact;

The 3rd connected mode: the common port of first and third relay connects normally opened contact, and the common port of second, four relays connects normally closed contact.

2. thin film electric resistivity automatic measuring instruments according to claim 1 is characterized in that, described voltage and current measurement module (5) adopts digital multimeter.

3. thin film electric resistivity automatic measuring instruments according to claim 2, it is characterized in that, described circuit handover module (2) also comprises digital multimeter connection terminal group (221) and the 5th relay, digital multimeter connection terminal group (221) comprises three connection terminals, second connection terminal is a common port, it is respectively with first, the 3rd connection terminal constitutes voltage measurement port and current measurement port, first connection terminal connects described voltage terminal V+, second connection terminal connects the normally opened contact of described voltage terminal V-and the 5th relay, and the 3rd connection terminal connects the normally closed contact and the constant current source (4) of the 5th relay.

4. thin film electric resistivity automatic measuring instruments according to claim 1, it is characterized in that, also be connected to probe location regulator (3) between described controller (1) and the four point probe (6), be used for adjusting the relative position of four point probe and sample according to the position control signal of controller (1).

5. thin film electric resistivity automatic measuring instruments according to claim 4, it is characterized in that, described probe location regulator (3) comprises vertical control assembly, horizontal control assembly, Spin Control parts and sample tray, vertical control assembly is used to control four point probe and moves up and down with respect to pallet, horizontal control assembly is used to control sample tray and moves horizontally with respect to four point probe, the pallet middle part is provided with the disk (39) that is used for load sample, the Spin Control parts are used to control disk around its central horizontal rotation, and described four point probe (6) is installed on vertical control assembly bottom.

6. thin film electric resistivity automatic measuring instruments according to claim 5 is characterized in that,

Described vertical control assembly comprises column (311), column (311) sidewall is fixed with vertical stepper motor (31), vertical stepper motor (31) connects vertical spiral shell rod (33) top, be with perpendicular displacement slide block (32) in vertical spiral shell rod (33) outer, upright position control step motor (31) makes perpendicular displacement slide block (32) move up and down along vertical spiral shell rod (33) by the vertical spiral shell rod of control (33) rotation, and described four point probe is fixed in perpendicular displacement slide block (32) bottom;

Described horizontal control assembly comprises horizontal stepper motor (34), horizontal stepper motor (34) joins with horizontal spiral shell rod (35) one ends, horizontal spiral shell rod (35) outer is with horizontal shift slide block (36), and horizontal stepper motor (34) makes horizontal shift slide block (36) move horizontally along horizontal spiral shell rod (35) by controlling level spiral shell rod (35) rotation; Horizontal shift slide block (36) sidewall is connected with described sample tray (37), and along with moving horizontally of sample tray horizontal level slide block (36), sample tray (37) also moves as respective horizontal;

Described Spin Control parts comprise the rotating stepper motor (38) that joins by gear and described disk (39).

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