Conductive film multi-probe measurement device and measurement method thereof

Abstract

A conductive film multi-probe measurement device and a measurement method thereof, which relate to the field of film detection technology, and solve the technical problem of controlling the probe force. The device comprises 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-applying component, the measurement base is provided with a movable base that can move up and down, and the measurement base is provided with an elastic return component for driving the movable base to return upward, and the probe base is fixed on the movable base; the measurement base is provided with a push rod, and a push rod driving component for driving the push rod to slide up and down, the lower end of the push rod is against the movable base, and the push rod is provided with a pressure sensor for detecting the vertical pressure borne by the push rod. The device and method provided by the present invention are suitable for measuring the square resistance of a conductive film.

Description

Technical Field

[0001] The invention relates to thin film detection technology, in particular to a conductive thin film multi-probe measuring device and a measuring method thereof. Background Art

[0002] The four-probe measurement method is widely used to measure the square resistance Rs in various fields, especially in the production and manufacturing of semiconductor integrated circuit chips. The four-probe measurement is an essential means for the detection of various conductive film preparation processes. The four-probe measurement of square resistance requires precise control of the penetration depth of the probe into the sample to ensure the accuracy of the measurement results.

[0003] Traditional four-probe measurement devices install the four-probe probe on a lifting frame, and control the height of the probe by driving the lifting frame up and down through an eccentric wheel (or other equipment). Each probe on the probe is equipped with a spring force mechanism. When this device measures the square resistance of the sample, the force applied by the probe on the sample is determined by the retraction stroke of the spring force mechanism.

[0004] 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, during long-term use, due to spring fatigue and other reasons, its elastic coefficient K may change, making it difficult to accurately control the probe force. Summary of the invention

[0005] In view of the defects existing in the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a conductive film multi-probe measurement device and a measurement method thereof which can accurately control the pressure of the probe on the sample being measured.

[0006] In order to solve the above technical problems, the present invention provides a conductive film multi-probe measuring device, comprising a measuring base and a probe seat; the probe seat is provided with a plurality of probes that can slide up and down, each probe is provided with an elastic force-applying component, the lower end of the elastic force-applying component is connected to the probe, and the upper end of the elastic force-applying 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 slide upward until the lower end of the probe is flush with the lower end of the probe seat; the characteristics are:

[0007] The measuring base is provided with a movable seat that can move up and down, and an elastic return component for driving the movable seat to return upward is provided on the measuring base, one end of the elastic return component is connected to the measuring base, and the other end is connected to the movable seat, and the probe seat is fixed on the movable seat;

[0008] 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, the lower end of the push rod abuts against the movable seat, and the push rod is provided with a pressure sensor for detecting the vertical pressure borne by the push rod.

[0009] Furthermore, a height measuring device for detecting the up and down sliding stroke of the push rod is provided on the measuring base.

[0010] The measuring method of the conductive film multi-probe measuring device provided by the present invention is characterized in that the specific steps are as follows:

[0011] The starting point of the push rod's downward stroke is defined as point a, the critical point when the push rod slides down to the point where the probe just touches the sample surface but does not exert pressure on the sample surface is defined as point b, and the critical point when the push rod slides down to the point where the probe just retracts upward to the end point of the stroke is defined as point c;

[0012] The sliding stroke of the push rod from point a to point b is defined as the first stage stroke; the sliding stroke of the push rod from point b to point c is defined as the second stage stroke;

[0013] The push rod driving component is used to drive the push rod to slide downward, and the vertical pressure borne by the push rod is measured by the pressure sensor;

[0014] The force on the probe is calculated in real time during the second stage of the push rod stroke, and the push rod stops sliding down when the calculated value of the force on the probe reaches the required set value;

[0015] The formula for calculating the probe force in the second stage of the push rod stroke is:

[0016] dlt_F = F_meas - F_calculate

[0017] Wherein, dlt_F is the force value of the probe, F_meas is the real-time value of the vertical pressure borne by the push rod in the second stage of the stroke, and F_calculate is the measured value of the vertical pressure borne by the push rod in the first stage of the stroke.

[0018] Furthermore, a height measuring device is used to measure the downward sliding stroke of the push rod, and a force curve of the probe in the second stage of the push rod is obtained based on the measured value of the downward sliding stroke of the push rod in the second stage of the stroke and the measured value of the vertical pressure borne by the push rod in the second stage of the stroke.

[0019] The conductive film multi-probe measuring device and measuring method provided by the present invention utilize an elastic return component to adjust the force of an elastic force-applying component on the probe, and implement feedback control of the needle lowering stroke and the probe force based on the measured value of the push rod's downward stroke and the measured value of the push rod's force, thereby achieving accurate and stable probe force control. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of a conductive thin film multi-probe measurement device according to an embodiment of the present invention;

[0021] Figure 2 , Figure 3 is a simplified diagram of the force mode of the conductive film multi-probe measurement device during the measurement process according to an embodiment of the present invention;

[0022] Figure 4 It is a schematic diagram of the relationship between the push rod stroke and the push rod force in the conductive film multi-probe measurement device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following is a further detailed description of an embodiment of the present invention in conjunction with the accompanying drawings, but this embodiment is not intended to limit the present invention. All similar structures and similar variations of the present invention should be included in the protection scope of the present invention. The commas in the present invention represent the relationship of and, and the English letters in the present invention are case-sensitive.

[0024] like Figure 1 As shown, a conductive film multi-probe measuring device provided by an embodiment of the present invention comprises a measuring base 1 and a probe base 2;

[0025] The probe seat 2 is provided with a plurality of probes 3 that can slide up and down, each probe is provided with an elastic force-applying component 4, the lower end of the elastic force-applying component 4 is connected to the probe 3, and the upper end of the elastic force-applying component 4 is connected to the probe seat 2; the lower end of each probe 3 is lower than the lower end of the probe seat 2, and each probe 3 can slide upward until the lower end of the probe is flush with the lower end of the probe seat;

[0026] The measuring base 1 is provided with a movable base 9 that can move up and down, and an elastic return component (not shown in the figure) for driving the movable base 9 to return upward is provided on the measuring base 1, one end of the elastic return component is connected to the measuring base 1, and the other end is connected to the movable base 9, and the probe base 2 is fixed on the movable base 9;

[0027] 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, the lower end of the push rod 5 is against the movable seat, the push rod 5 is provided with a pressure sensor 6 for detecting the vertical pressure borne by the push rod, and the measuring base 1 is provided with a height measuring device 8 for detecting the upward and downward sliding stroke of the push rod.

[0028] In an embodiment of the present invention, the elastic force-applying component and the elastic return component are both springs, the pressure sensor is a piezoelectric pressure sensor, the height measuring device is a laser rangefinder, and the push rod driving component is a linear motor. In other embodiments of the present invention, the elastic force-applying component and the elastic return component may also be other elastic components, the pressure sensor may also be other existing pressure sensors, the height measuring device may also be other existing distance measuring devices such as a displacement sensor, and the push rod driving component may also be other existing power output devices such as a cylinder.

[0029] The working principle of the embodiment of the present invention is as follows:

[0030] The movable seat 9, the probe seat 2 and the components installed on the probe seat (probe 3, elastic force-applying component 4) constitute a measuring probe. Figure 2 , Figure 3 It is a simplified diagram of the force mode during the measurement process of the embodiment of the present invention, Figure 2 , Figure 3 Where 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, F1 is the elastic force of the elastic return component acting on the movable seat, G is the equivalent gravity of the measuring probe, and F_P is the downward thrust exerted by the push rod on the movable seat;

[0031] In the initial state ( Figure 2 In the state shown in the figure), the push rod 5 does not apply a downward thrust to the movable seat 9. At this time, the elastic return component is only subjected to the gravity of the measuring probe. At this time, F1 and G are equal in magnitude and opposite in direction. At this time, the probe 3 is at a distance D0 from the sample surface;

[0032] The push rod driving component 7 is used to drive the push rod 5 to slide downward, so that the push rod 5 pushes the movable seat 9 in the measuring probe to overcome the elastic force of the elastic return component and slide downward, thereby pushing the measuring probe downward;

[0033] When the lower end of the probe 3 of the measuring probe just touches the sample surface ( Figure 3 In the state shown in 3a in FIG), F1 is proportional to the deformation range of the elastic return component, and F1=G+k1×D0. At this time, the downward thrust exerted by the push rod on the movable seat is: F_P=F1-G;

[0034] As the push rod continues to move downward, the probe 3 begins to shrink upward due to the resistance of the sample, and the elastic force-applying component also begins to shrink, thereby generating an upward force on the measuring probe. When the probe 3 just retracts upward to the end point of the stroke ( Figure 3In the state shown in 3b, the lower end of the probe is flush with the lower end of the probe seat), the elastic force of the elastic force component remains constant, and F_pin=k2×ΔD1, where F_pin is the elastic force of the elastic force component, and ΔD1 is the contraction length of the elastic force component; at this time, F1= G+k1×(D0+ΔD1);

[0035] 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, and F1= G+k1×(D0+ΔD1+ΔD2), where D0+ΔD1 is the total downward stroke of the measuring probe (also the downward stroke of the push rod), and the elastic force F1 of the elastic return component and the downward thrust F_P of the push rod offset each other.

[0036] Figure 4 It is a schematic diagram of the relationship between the push rod stroke and the push rod force. Figure 4 The horizontal axis in 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. Figure 4 The longitudinal axis in is the vertical pressure borne by the push rod, which can be measured by the pressure sensor 6;

[0037] Figure 4 Point a in the figure is the starting point of the push rod's downward stroke, point b is the critical point when the push rod slides down to the point where the probe just touches the sample surface but does not exert pressure on the sample surface, point c is the critical point when the push rod slides down to the point where the probe just retracts upward to the end point of the stroke, and point d is the end point of the push rod's downward stroke;

[0038] like Figure 4 As shown in the figure, during the downward sliding of the push rod, the force process of the push rod is described by three slashes, wherein the slash segment ab represents the force state of the push rod when the probe has not yet contacted the sample surface, the slash segment bc represents the force state of the push rod when the probe is retracted upward, and the slash segment cd represents the force state of the push rod when the probe is fully retracted;

[0039] Depend on Figure 4 It can be seen that the slope of the oblique line segment bc is significantly different from that of the oblique line segment ab and the oblique line segment cd. This is because the elastic force of the elastic force-applying component changes as the probe retracts upward. At this time, the magnitude of the force applied to the probe can be obtained by taking the difference between the actual measured push rod force and the push rod force in the oblique line segment ab stroke.

[0040] The measurement method of the embodiment of the present invention is as follows:

[0041] The starting point of the push rod's downward stroke is defined as point a, the critical point when the push rod slides down to the point where the probe just touches the sample surface but does not exert pressure on the sample surface is defined as point b, and the critical point when the push rod slides down to the point where the probe just retracts upward to the end point of the stroke is defined as point c;

[0042] The sliding stroke of the push rod from point a to point b is defined as the first stage stroke ( Figure 4 The oblique line segment ab in the figure); the sliding stroke of the push rod from point b to point c is defined as the second stage stroke ( Figure 4 The oblique line segment bc in it);

[0043] The push rod driving component 7 is used to drive the push rod 5 to slide downward (so that the push rod 5 pushes the measuring probe to move downward), and the downward sliding stroke of the push rod is measured by the height measuring device 8, and the vertical pressure borne by the push rod is measured by the pressure sensor 6;

[0044] The force on the probe is calculated in real time during the second stage of the push rod stroke, and the push rod stops sliding down when the calculated value of the force on the probe reaches the required set value;

[0045] The formula for calculating the probe force in the second stage of the push rod stroke is:

[0046] dlt_F = F_meas - F_calculate

[0047] Wherein, dlt_F is the force value of the probe, F_meas is the real-time value of the vertical pressure borne by the push rod in the second stage of the stroke, and F_calculate is the measured value of the vertical pressure borne by the push rod in the first stage of the stroke.

[0048] In the second stage of the push rod's stroke, the probe force value dlt_F will gradually increase and reach saturation. The probe force curve in the second stage of the push rod's stroke can be obtained based on the measured value of the push rod's downward sliding stroke in the second stage of the stroke and the measured value of the vertical pressure the push rod is borne in the second stage of the stroke. If the initial distance between the sample and the probe does not change during the next measurement, the push rod stroke can be directly calculated based on the set needle pressure and the recorded probe force curve, and the push rod can be directly controlled to reach this stroke.

Claims

1. A conductive film multi-probe measuring device, comprising a measuring base and a probe base; the probe base is provided with a plurality of probes that can slide up and down, each probe is provided with an elastic force-applying component, the lower end of the elastic force-applying component is connected to the probe, and the upper end of the elastic force-applying component is connected to the probe base; the lower end of each probe is lower than the lower end of the probe base, and each probe can slide upward until the lower end of the probe is flush with the lower end of the probe base; the characteristics are: The measuring base is provided with a movable seat that can move up and down, and an elastic return component for driving the movable seat to return upward is provided on the measuring base, one end of the elastic return component is connected to the measuring base, and the other end is connected to the movable seat, and 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, the lower end of the push rod abuts against the movable seat, and the push rod is provided with a pressure sensor for detecting the vertical pressure borne by the push rod.

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

3. The measuring method of the conductive thin film multi-probe measuring device according to claim 1 or 2, characterized in that: The starting point of the push rod's downward stroke is defined as point a, the critical point when the push rod slides down to the point where the probe just touches the sample surface but does not exert pressure on the sample surface is defined as point b, and the critical point when the push rod slides down to the point where the probe just retracts upward to the end point 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 sliding stroke of the push rod from point b to point c is defined as the second stage stroke; The push rod driving component is used to drive the push rod to slide downward, and the vertical pressure borne by the push rod is measured by the pressure sensor; The force on the probe is calculated in real time during the second stage of the push rod stroke, and the push rod stops sliding down when the calculated value of the force on the probe reaches the required set value; The formula for calculating the probe force in the second stage of the push rod stroke is: dlt_F = F_meas - F_calculate Wherein, dlt_F is the force value of the probe, F_meas is the real-time value of the vertical pressure borne by the push rod in the second stage of the stroke, and F_calculate is the measured value of the vertical pressure borne by the push rod in the first stage of the stroke.

4. The measuring method of the conductive film multi-probe measuring device according to claim 3, characterized in that: The downward sliding stroke of the push rod is measured by a height measuring device, and the probe force curve in the second stage of the push rod stroke is obtained according to the measured value of the downward sliding stroke of the push rod in the second stage of the stroke and the measured value of the vertical pressure borne by the push rod in the second stage of the stroke.

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