CN211554146U - Conductive film multi-probe measuring device - Google Patents

Abstract

A multi-probe measuring device for conductive thin films relates to the technical field of thin film detection and solves the technical problem of controlling probe force. The device includes a measurement base and a probe base; the probe base is provided with a plurality of probes, each probe is provided with an elastic force member, and the measurement base is provided with a movable seat that can move up and down, And on the measurement base, there is an elastic return part for driving the movable seat to return upward, and the probe seat is fixed on the movable seat; the measurement base is provided with a push rod, and is used for driving the push rod to slide up and down. The lower end of the push rod is against the movable seat, and the push rod is provided with a pressure sensor for detecting the vertical pressure that the push rod bears. The device provided by the utility model is suitable for measuring the sheet resistance of the conductive thin film.

Description

Conductive thin film multi-probe measurement device

technical field

The utility model relates to a thin film detection technology, in particular to a technology of a multi-probe measuring device for a conductive thin film.

Background technique

The four-probe measurement method is widely used in the measurement of sheet resistance Rs in various fields, especially in the production and manufacture of semiconductor integrated circuit chips. Using four probes to measure the sheet resistance requires precise control of the penetration depth of the probe into the sample to ensure the accuracy of the measurement results.

The traditional four-probe measuring device installs the four-probe probe on a lifting frame, and drives the lifting frame to move up and down through the eccentric wheel (or other equipment) to control the height of the probe. Spring energizing mechanism, when measuring the sheet resistance of the sample, the force exerted by the probe on the sample is determined by the retraction stroke of the spring energizing mechanism.

In actual use, the elastic coefficient of the probe spring is not a simple linear function of the stroke. In order to establish the relationship between the stroke and the spring force, a complex pre-calibration process is required; in addition, in long-term use, due to spring fatigue and other reasons, its The elastic coefficient K may vary, making it difficult to precisely control the probe force.

Utility model content

In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to provide a conductive film multi-probe measuring device that can precisely control the pressure of the probe on the sample to be measured.

In order to solve the above technical problems, the utility model provides a conductive film multi-probe measurement device, comprising a measurement base and a probe seat; the probe seat is provided with a plurality of probes that can slide up and down, each probe The upper end is provided with an elastic force component, the lower end of the elastic force component is connected to the probe, and the upper end of the elastic force component is connected to the probe seat; the lower end of each probe is lower than the lower end of the probe seat, and each probe can be Slide up until the lower end of the probe is flush with the lower end of the probe base; it is characterized by:

The measurement base is provided with a movable seat that can move up and down, and an elastic return part for driving the movable seat to return upward is provided on the measurement base. One end of the elastic return part is connected to the measurement base, and the other end is connected to the measurement base. a movable seat, the probe seat is fixed on the movable seat;

The measuring base is provided with a push rod that can slide up and down, and a push rod driving component for driving the push rod to slide up and down. Pressure sensor for vertical pressure.

Further, the measuring base is provided with a height measuring device for detecting the up and down sliding stroke of the push rod.

The measuring method of the conductive film multi-probe measuring device provided by the utility model has the following specific steps:

The starting point of the sliding stroke of the plunger is defined as point a, the critical point when the plunger is slid so that the probe just touches the sample surface but no pressure is applied to the sample surface is defined as point b, and the plunger is slid so that the probe is just up The critical point when retracting to the end of the stroke is defined as point c;

The sliding stroke of the push rod sliding from point a to point b is defined as the first stage stroke; the sliding stroke of the push rod sliding from point b to point c is defined as the second stage stroke;

Use the push rod driving part to drive the push rod to slide down, and use the pressure sensor to measure the vertical pressure on the push rod;

Calculate the force of the probe in real time during the second-stage stroke of the push rod, and stop the sliding of the push rod when the calculated value of the force of the probe reaches the required set value;

The calculation formula of the probe force in the second stage stroke of the push rod is:

dlt_F= F_meas-F_calculate

In the formula, dlt_F is the force value of the probe, F_meas is the real-time value of the vertical pressure that the push rod bears in the second-stage stroke, and F_calculate is the measured value of the vertical pressure that the push rod bears during the first-stage stroke.

Further, a height measuring device is used to measure the downward sliding stroke of the push rod, and the measured value is measured according to the downward sliding stroke of the push rod in the second stage of the stroke, and the vertical pressure measured by the push rod in the second stage of the stroke. If the value is obtained, the force curve of the probe in the second-stage stroke of the push rod is obtained.

The multi-probe measuring device of the conductive film provided by the utility model uses the elastic return part to adjust the force of the elastic force member on the probe, and realizes the measurement according to the measured value of the sliding stroke of the push rod and the measured value of the force of the push rod. The feedback control of lower needle stroke and probe force can realize precise and stable probe force control.

Description of drawings

1 is a schematic structural diagram of a multi-probe measuring device for conductive thin films according to an embodiment of the present invention;

FIG. 2 and FIG. 3 are simplified diagrams of the force-bearing mode of the multi-probe measuring device of the conductive thin film according to the embodiment of the present invention during the measurement process;

4 is a schematic diagram of the relationship between the stroke of the push rod and the force of the push rod in the conductive film multi-probe measurement device according to the embodiment of the present invention.

Detailed ways

The embodiments of the present utility model will be described in further detail below in conjunction with the accompanying drawings, but the present embodiments are not intended to limit the present utility model. Any similar structures and similar changes of the present utility model shall be included in the protection of the present utility model. Scope, the commas in the present utility model all represent the relationship of and, and the English letters in the present utility model are case-sensitive.

As shown in FIG. 1 , a conductive film multi-probe measurement device provided by an embodiment of the present invention includes a measurement base 1 and a probe base 2;

The probe base 2 is provided with a plurality of probes 3 that can slide up and down, each probe is provided with an elastic force member 4, the lower end of the elastic force member 4 is connected to the probe 3, and the elastic force member 4 is provided with a lower end. The upper end is connected to the probe base 2; the lower end of each probe 3 is lower than the lower end of the probe base 2, and each probe 3 can slide upward until the lower end of the probe is flush with the lower end of the probe base;

The measurement base 1 is provided with a movable seat 9 that can move up and down, and an elastic return member (not shown in the figure) for driving the movable seat 9 to return upward is provided on the measurement base 1. The elastic return member One end is connected to the measurement base 1, the other end is connected to the movable seat 9, and the probe seat 2 is fixed on the movable seat 9;

The measuring base 1 is provided with a push rod 5 that can slide up and down, and a push rod driving component 7 for driving the push rod to slide up and down. A pressure sensor 6 for measuring the vertical pressure of the push rod, and a height measuring device 8 for detecting the up and down sliding stroke of the push rod is provided on the base 1 .

In the embodiment of the present utility model, the elastic force component and the elastic return component are both springs, the pressure sensor adopts a piezoelectric pressure sensor, the height measuring device adopts a laser range finder, a push rod The driving component adopts a linear motor. In other embodiments of the present invention, the elastic force component and the elastic return component can also use other elastic components, the pressure sensor can also use other existing pressure sensors, and the height measuring device can also be used. Other existing distance measuring devices such as displacement sensors can be used, and other existing power output devices such as cylinders can also be used for the push rod driving components.

The working principle of the embodiment of the present utility model is as follows:

The movable seat 9, the probe seat 2 and the components installed on the probe seat (the probe 3, the elastic force member 4) constitute the measuring probe. Figures 2 and 3 are simplified force modes of the embodiment of the present invention during the measurement process. Fig. 2 and Fig. 3 k1 is the equivalent elastic coefficient of the elastic return component, k2 is the equivalent elastic coefficient of the elastic force component, M is the equivalent mass of the measuring probe, and F1 is the elastic return component acting on the Elastic force on the movable seat, G is the equivalent gravity of the measuring probe, F_P is the downward thrust exerted by the push rod on the movable seat;

In the initial state (the state shown in Fig. 2), the push rod 5 does not exert a downward thrust on the movable seat 9, and the elastic return part is only subjected to the gravity of the measuring probe. At this time, the magnitudes of F1 and G are equal and the direction On the contrary, at this time, the probe 3 has a distance D0 from the sample surface;

Utilize the push rod driving part 7 to drive the push rod 5 to slide down, so that the push rod 5 pushes the movable seat 9 in the measuring probe to overcome the elastic force of the elastic return part to slide down, and then push the measuring probe downward;

When the lower end of the probe 3 of the measuring probe just touches the surface of the sample (the state shown by 3a in Figure 3), F1 is proportional to the deformation extension of the elastic return part, there is F1=G+k1×D0, at this time push The downward thrust exerted by the rod on the movable seat is: F_P=F1-G;

As the push rod continues to move downward, the probe 3 begins to retract upwards due to the resistance of the sample, and the elastic force member also begins to contract, thereby generating an upward force on the measuring probe. At the point (the state shown by 3b in Figure 3, at this time the lower end of the probe is flush with the lower end of the probe base), the elastic force of the elastic force member remains constant, with F_pin=k2×ΔD1, where F_pin is the elastic force. The elastic force of the force component, ΔD1 is the contraction length of the elastic force component; at this time, F1= G+k1×(D0+ΔD1);

As the push rod continues to move downward, the elastic force F1 of the elastic return component and the downward thrust F_P of the push rod continue to increase, there is F1= G+k1×(D0+ΔD1+ΔD2), where D0+ΔD1 is the measuring probe The total stroke of the downward movement (also the sliding stroke of the push rod), the elastic force F1 of the elastic return part and the downward thrust F_P of the push rod cancel each other out.

Figure 4 is a schematic diagram of the relationship between the stroke of the push rod and the force of the push rod. The horizontal axis in Figure 4 is the downward sliding stroke of the push rod driven by the push rod driving component. The downward sliding stroke of the push rod can be measured by the height measuring device 8 So, the vertical axis in Fig. 4 is the vertical pressure that the push rod bears, and this vertical pressure can be measured by the pressure sensor 6;

Point a in Fig. 4 is the starting point of the sliding stroke of the push rod, point b is the critical point when the push rod slides down to the point where the probe just touches the surface of the sample but no pressure is applied to the surface of the sample, and point c is the point where the push rod slides down so that the probe The critical point when it is just retracted upwards to the stroke dead point, the d point is the sliding stroke dead point of the push rod;

As shown in Figure 4, during the downward sliding of the push rod, the process of the push rod being stressed is described by three oblique lines. The line segment bc represents the force state of the push rod in the upward retraction stage of the probe, and the oblique line segment cd represents the force state of the push rod in the stage of the fully retracted probe;

As can be seen from Figure 4, the slope of the oblique line segment bc is significantly different from the oblique line segment ab and the oblique line segment cd. This is because the elastic force of the elastic force member also changes as the probe retracts upward. At this time, the probe The magnitude of the force can be obtained from the difference between the actual measured force of the push rod and the force of the push rod in the stroke of the inclined line ab.

The measuring method of the embodiment of the present invention is as follows:

The starting point of the sliding stroke of the plunger is defined as point a, the critical point when the plunger is slid so that the probe just touches the sample surface but no pressure is applied to the sample surface is defined as point b, and the plunger is slid so that the probe is just up The critical point when retracting to the end of the stroke is defined as point c;

The sliding stroke of the push rod from point a to point b is defined as the first stage stroke (the oblique line segment ab in Figure 4); the sliding stroke of the push rod from point b to point c is defined as the second stage stroke (Figure 4). slash segment bc in 4);

Use the push rod driving part 7 to drive the push rod 5 to slide down (so that the push rod 5 pushes the measuring probe to move downward), and use the height measuring device 8 to measure the downward sliding stroke of the push rod, and use the pressure sensor 6 to measure the pressure of the push rod vertical pressure;

Calculate the force of the probe in real time during the second-stage stroke of the push rod, and stop the sliding of the push rod when the calculated value of the force of the probe reaches the required set value;

The calculation formula of the probe force in the second stage stroke of the push rod is:

dlt_F= F_meas-F_calculate

In the formula, dlt_F is the force value of the probe, F_meas is the real-time value of the vertical pressure that the push rod bears in the second-stage stroke, and F_calculate is the measured value of the vertical pressure that the push rod bears during the first-stage stroke.

In the second-stage stroke of the push rod, the probe force value dlt_F will gradually increase and reach saturation. The measured value of the vertical pressure during the stroke can be used to obtain the force curve of the probe in the second-stage stroke of the push rod. If the initial distance between the sample and the probe does not change in the next measurement, it can be determined according to the set lower pressure. The needle pressure and the recorded probe force curve can directly obtain the stroke of the push rod, and the push rod can be directly controlled to reach this stroke.

Claims (2)

1. A conductive film multi-probe measuring device comprises a measuring base and a probe seat; a plurality of probes capable of sliding up and down are arranged on the probe seat, each probe is provided with an elastic stressing component, the lower end of the elastic stressing component is connected with the probe, and the upper end of the elastic stressing component is connected with the probe seat; the lower end of each probe is lower than the lower end of the probe seat, and each probe can slide upwards until the lower end of the probe is flush with the lower end of the probe seat; the method is characterized in that:

the measuring base is provided with a movable seat capable of moving up and down, the measuring base is provided with an elastic return part for driving the movable seat to return upwards, one end of the elastic return part is connected with the measuring base, the other end of the elastic return part is connected with the movable seat, and the probe seat is fixed on the movable seat;

the measuring base is provided with a push rod capable of sliding up and down and a push rod driving part used for driving the push rod to slide up and down, the lower end of the push rod props against the movable seat, and the push rod is provided with a pressure sensor used for detecting the vertical pressure born by the push rod.

2. The conductive thin film multi-probe measuring device according to claim 1, characterized in that: and a height measurer for detecting the up-and-down sliding stroke of the push rod is arranged on the measuring base.

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