JPH11311628A - Displacement detection probe, position measuring device and position control device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a displacement detection probe, capable of composing a detection system suitable for integration in simple structure by composing a displacement detection system of a resistor, in which a resistance value changes with the temperature change of the probe. SOLUTION: A displacement detection probe 101 has a cantilever structure by the displacement detection probe provided with a dispacement system using piezoresistance. The change in the electrical resistance value of the displacement detection probe 101 is measured by a connected resistant measuring part 107. Since the measured value indicates a distance between a substrate 102 and the probe, a control part 106 controls the operation of a proximity control part 108 by means of the value. The proximity control part 108 has an actuator, and the distance between the specimen substrate 102 and the probe is determined by having the actuator driven practically. A scanning signal transmitted from a scanning signal generation part 5 is scanned through an amplifier 104 on a stage 103. Sweep width setting, sweep speed setting, positioning for a designated place or the like from the scanning signal generation part 105 are controlled by the control part 106.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement detection probe used for a measuring instrument such as a scanning probe microscope or the like, a fine processing machine using the same, or an ultra-high density recording / reproducing apparatus, and a position having the probe. The present invention relates to a measuring device and a position control device.

[0002]

2. Description of the Related Art In recent years, a probe is brought closer to a sample, and a physical probe (tunnel phenomenon, atomic force, or the like) generated at that time is used to directly observe a material surface and an electronic structure near the surface. Microscopes (hereinafter abbreviated as SPMs) have been developed, and real-space images of various physical quantities, whether single-crystal or amorphous, can be measured with high resolution. In the industrial field, in recent years, attention has been paid to the principle of high resolution of the atomic or molecular size of SPM and disclosed in JP-A-63-16155.
As disclosed in Japanese Patent Publication No. 2 and JP-A-63-161553, application and practical application to an information recording / reproducing apparatus by using a recording layer in a medium have been energetically advanced.

Further, with the recent progress of semiconductor process technology, the density of devices such as VLSI is increasing. Under such circumstances, it is necessary to fabricate and evaluate devices and processes in a large area, and SPM has been used as one of the techniques. However, although the resolution of SPM is high, it takes too much time for one probe to observe a large area, and it is not practical. Therefore, it has been studied to use a plurality of probes to perform observation by parallel processing (multiplication). In addition, due to recent advances in process technology, it has become relatively easy to form a plurality of such probes on the same substrate by a semiconductor process.

[0004]

When a recording / reproducing system or an observation system as described above is constructed, for example, in the case of a recording / reproducing system, in order to improve a transfer rate,
In the case of an observation system, it is necessary to evaluate a large area (wafer unit), and it is necessary to arrange several hundred to several thousand probes on a plane. In addition, in order to match the distance at which all of these two-dimensionally arranged probes can interact with the sample substrate, it is essential to control the distance between the substrate surface and the substrate on which the probe is formed. For this purpose, for example, it is necessary to provide a plurality of measurement mechanisms for measuring the distance between the probe substrate and the sample substrate on the probe substrate, and to keep the distance constant by feedback control. However, when such distance measurement is performed simultaneously at a plurality of points, it is necessary to configure a plurality of photodetection systems in the optical lever type AFM conventionally used, and the system is very complicated and large. Therefore, there is a problem in that it is not suitable for integration or the like.

Accordingly, the present invention solves the above-mentioned problems, and provides a displacement detection probe capable of forming a detection system suitable for integration with a simple structure, and a displacement detection and displacement control using the probe. An object of the present invention is to provide a position measuring device and a position control device which can be performed with high accuracy and can easily cope with complication of a system due to mixing with other functional probes.

[0006]

In order to achieve the above object, the present invention is characterized in that a displacement detection probe and a position measuring device and a position control device having the probe are configured as follows. It is. That is, the probe of the present invention is a probe provided with a displacement detection system, wherein the displacement detection system is constituted by a resistor whose resistance value changes with a change in temperature of the probe. Further, the probe of the present invention is characterized in that the probe is made of a semiconductor. Further, the probe of the present invention is characterized in that the probe is constituted by a piezoresistor. Further, the probe of the present invention is characterized in that the probe is formed of a platinum resistor. Further, a position measuring device according to the present invention includes any one of the above-described probes according to the present invention, and resistance measuring means for measuring a resistance value of a resistor of the probe, and the probe measured by the resistance measuring means. The distance between the probe and the substrate facing the probe is determined by the resistance value of the probe. Further, the position control device of the present invention includes any one of the above-described probes of the present invention, and resistance measuring means for measuring a resistance value of a resistor of the probe, and the probe measured by the resistance measuring means. Is characterized in that the distance between the probe and the substrate facing the probe is controlled to be constant with reference to the resistance value.

[0007]

According to the present invention, the distance between the sample substrate and the resistor lever can be detected by the output value of the resistance measuring means by using the displacement detecting probe having the above-described simple structure. Further, the distance between the sample substrate and the resistor lever can be controlled by feedback control using the detected value. Therefore, according to the present invention, the distance between the distance measuring lever and the sample substrate can be detected with high accuracy, or the distance can be controlled with high precision.

[0008]

Embodiments of the present invention will be described below. [Embodiment 1] FIG. 1 is a diagram schematically showing a configuration of a position measuring device and a position control device using a probe of the present invention in Embodiment 1 of the present invention. Reference numeral 101 denotes a displacement detection probe having a displacement system using a piezoresistor, which has a cantilever structure. Details of the structure will be described later. The change in the electric resistance value of the probe is measured by the connected resistance measuring unit 107. As will be described later, since this measured value indicates the distance between the substrate 102 and the probe, the control unit 106 in the subsequent stage controls the operation of the approach control unit 108 using the measured value. The approach control unit 108 has an actuator (in this embodiment, a stacked piezoelectric actuator is used on the probe side), and determines the distance between the sample substrate 102 and the probe by actually driving the actuator. In this embodiment, conventional PID control is used as a control method. The stage 103 is scanned by applying a scanning signal output from the scanning signal generation unit 106 to a stage actuator (in this embodiment, a laminated piezoelectric actuator is used) as a drive signal through an amplifier 104. The scanning signal generation unit 105 is controlled by the control unit 106 to set the sweep width, set the sweep speed, and control the positioning to a designated place.

FIG. 2 shows a specific structure of the displacement detection probe 101 shown in FIG. The probe 101 is a cantilever and has a probe 201 at the tip. This probe is an n-type Si
A p-type piezoresistor 204 is formed on a substrate to form a lever, and the structure is as shown in the figure below.
The method of manufacturing this probe is described in JP-A-5-1964.
No. 58 was formed using the same process as that using an SOI substrate. 203 is a substrate and a cantilever arm, 204 is a piezoresistor, 201 is a probe,
205 is an insulator protection layer, and 202 is a metal wiring pattern. H is the effective length of the cantilever, W is the effective width of 1
/ 2, H indicate the thickness of the lever. The magnitude changes the mechanical properties (elastic constant and resonance frequency) of the lever and also affects the magnitude of the piezoresistance. The probe used in this example is W = 20 μm, L = 50 μ
m, H = 2 μm, piezoresistor thickness = 0.2 μm,
The resistance value R _init when no stress was applied was 14 kΩ (fluctuation between probes: 0.01%). The height of the probe is 2 μm, and the resonance frequency of the entire lever is 1
It was 120 kHz in the next mode.

In order to measure displacement by resistance using such a probe, a bridge circuit can be used. It is as shown in FIG. 7, and the resistance value (R
The change in s) is to be measured by the change in the potential difference between points A and B. The potential difference between the points A and B is detected by being amplified to a required magnification by a differential amplifier at the subsequent stage. At this time, in order to obtain a sufficient magnification, an initial state (a state in which the resistance does not change in the probe). A)
It is desirable that the potential difference between the points B is zero. In the case of actual measurement, a resistor for measuring a resistance change is inserted into a bridge as shown in FIG.

Now, the principle of performing position detection using such a probe will be described. The resistance of the resistor can be changed by heat, and the change depends on the material of the resistor. When the resistor is a metal resistor or the like, the resistance value increases as the temperature increases. This is a type in which lattice vibration becomes more intense due to a rise in temperature, and impedes the movement of electrons, which are current. On the other hand, in the case of a semiconductor or the like, since the amount of charge as a carrier increases due to a rise in temperature, a heat-active type in which current easily flows is used. Since the resistor of the probe used in this embodiment is a P-type semiconductor, it is considered that the latter phenomenon of thermal activation occurs predominantly. That is, the resistance value of the piezoresistor changes in the direction of decreasing with the temperature rise of the probe.

On the other hand, a current flows through the lever for measuring its resistance value, and the lever generates heat by Joule heat. In the case of the probe used in this embodiment, 3
When a current of about 50 μA flows and there is no endothermic substance in the air, the temperature rises to about 50 ° C. However, when there is an endothermic substance such as a conductor nearby, the equilibrium point of the lever temperature changes as the substance is approached, and therefore the resistance value also changes. FIG. 4 shows a change in resistance value when the probe is actually brought close to the sample. The probe position on the horizontal axis is a direction approaching the probe as going to the right of the graph. The resistance value changes gradually according to the change in distance. This is because when the lever approaches the substrate, the temperature decreases and the resistance value increases. Further, greatly changes the probe position at a distance L ₀ when moved toward the sample substrate. This is because the probe disposed at the tip of the probe comes into contact with the sample substrate and the lever is bent, causing a large change in resistance.

Next, the position is measured from this signal change.
Positioned to measure the measured in advance in accordance with the lever characteristics shown in FIG. 4, to determine the distance to look at the resistance change from the position of the contact point L _0. Change of displacement and resistance value as a reference contact point L ₀ is smaller as the temperature change of the substrate can be neglected due to very larger that of the substrate as compared to the heat capacity of the lever, therefore the lever and the material of the substrate , Shape, method of preparation, and atmosphere alone, and conversely, if they are constant, characteristics with good reproducibility can be obtained.

The resistance-displacement characteristic to be measured in advance can be measured by a system exactly the same as the system of the present invention. In this case, it is necessary to take a sufficient time after setting the amount of displacement in order to suppress the creep phenomenon of the piezoelectric element as the driving mechanism. To measure the resistance, and to measure by using a vibration isolation table, a soundproof room, or the like to suppress external noise such as vibration. However, the measurement points need not be continuous, but can be measured discretely and approximated by a curve. After the characteristic measurement, the procedure of the actual distance measurement is as follows. First, the probe and the substrate are approached by the approach mechanism, and the resistance value R ₀ of the contact point L ₀ is obtained. Bring to a position to be measured a probe for measuring the resistance R _1. As a result, ΔR shown in FIG. 4 is obtained, and thus ΔL is obtained from the characteristic curve. Since the position L ₀ has been measured, the position of L ₁ was determined.

[Second Embodiment] In the second embodiment, the position control is performed using the configuration used in the first embodiment. First, the positions of the probe and the sample substrate are set as in the first embodiment. That is, a resistance value representing a desired distance is set from a contact point (L ₀ in FIG. 4) between the probe and the substrate, and a drive signal is applied to the piezoelectric drive element by the control unit 106 in FIG. . In this embodiment, the distance between the probe sample substrates was controlled by PID control.

Since the system of the present invention can also add a conventional AFM system, when a different system capable of measuring the displacement of the probe due to interference by a laser beam is prepared and measured, for example, the fluctuation is 1 nm or less. And this variation is ΔL
Was maintained up to about 10 μm. It was found that the position can be fixed with higher accuracy than this. In the measurement using this light, the position was measured by irradiating the laser as a light pulse so as not to raise the temperature of the lever.

[Embodiment 3] In the embodiment 3, the position detecting probe is constituted by a platinum resistor. The configuration is exactly the same as that of the block diagram shown in FIG. The configuration of the probe is as shown in FIG. 5, where 603 is a substrate and a cantilever arm (Si), 604 is a platinum resistor, and 601 is a probe (A).
u) and 602 are metal wiring patterns (Al). H is the effective thickness of the cantilever, W is の of the effective width, L
Indicates the effective length. The mechanical properties of this beam are determined by these sizes and materials. The beam needs to have a small elastic constant in order to reduce damage to the sample substrate when the lever comes into contact with the sample substrate. In the present embodiment, the one having W = 20 μm, H = 2 μm, and L = 50 μm was used. The thickness of the platinum resistor (604) is 500
Å was formed by sputtering. Resistance is 1.2 at room temperature
kΩ.

When the displacement was measured by resistance using the lever described above, a bridge circuit was used as in the first embodiment. At this time, a current of 830 μA flowed through the lever at a voltage of 10 V, and the lever temperature was about 80 ° C. in the normal temperature atmosphere when there was no heat absorber near the lever. Since the platinum resistance is a metal resistance, the resistivity increases as the temperature increases. As in the first embodiment, since the temperature of the lever changes due to the change in thermal equilibrium due to the distance between the lever and the substrate, the resistance value changes according to the distance between the probe and the substrate. FIG. 6 shows an example of the change. The probe position on the horizontal axis is a direction approaching the probe as going to the right of the graph.

Next, as in the first embodiment, the position can be measured from this signal change. After the characteristic measurement shown in FIG. 6 as in the first embodiment, an actual distance measurement is performed. First, the probe and the substrate are brought close to each other by the approach mechanism, and the resistance value R ₀ at the contact point L ₀ is obtained. Bring to a position to be measured a probe for measuring the resistance R _1. As a result, ΔR shown in FIG. 6 is obtained, and thus ΔL is obtained from the characteristic curve. Since the position L ₀ has been measured, the position of L ₁ was determined.

[Embodiment 4] In Embodiment 4, the position control is performed using the configuration used in Embodiment 3. First, the positions of the probe and the sample substrate are set as in the first embodiment. That is, a resistance value indicating a desired distance is set from a contact point (L ₀ in FIG. 6) between the probe and the substrate, and a drive signal is applied to the piezoelectric drive element by the control unit 110 in FIG. . In this embodiment, the distance between the probe sample substrates was controlled by PID control. Since the system of the present invention can add a conventional AFM system, for example, when another system that can measure the displacement of the probe due to interference by laser light is prepared and measured, the fluctuation is 0.
This variation was 5 nm or less, and this variation was maintained until ΔL was about 10 μm. It was found that the position can be fixed with higher accuracy than this. In the measurement using this light, the position was measured by irradiating the laser as a light pulse so as not to raise the temperature of the lever.

[0021]

As described above, according to the present invention, by forming the probe with a resistor whose resistance value changes with a temperature change, a detection system suitable for integration can be formed with a simple structure. Can be performed using the probe.
A position that can perform displacement detection and displacement control with multiple probes, such as keeping two surfaces parallel, with high accuracy, and can easily cope with complication of the system due to mixing with other functional probes. A measuring device and a position control device can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a configuration of a position measurement and position control device used in a first embodiment.

FIG. 2 is a structure and an external view of a piezoresistive displacement detection probe.

FIG. 3 is a schematic diagram of a resistance measurement circuit.

FIG. 4 is a distance-dependent curve of a detected resistance value.

FIG. 5 is a structure and an outline view of a platinum displacement detection probe.

FIG. 6 is a distance-dependent curve of a detected resistance value.

FIG. 7 is a view for explaining measurement of a sample resistance by a bridge circuit.

[Explanation of symbols]

 101: Displacement detection probe 102: Substrate 103: Stage 104: Amplifier 105: Scan signal generation unit 106: Control unit 107: Resistance measurement unit 108: Access control unit 201: Probe 202: Metal wiring pattern 203: Cantilever arm 204 : Piezoresistor 205: Insulator protection layer 601: Probe 602: Metal wiring pattern 603: Cantilever arm 604: Platinum resistor

Claims (6)

[Claims] 1. A displacement detection probe comprising a displacement detection system, wherein the displacement detection system comprises a resistor whose resistance value changes with a change in temperature of the probe. 2. The displacement detection probe according to claim 1, wherein said probe is made of a semiconductor. 3. The displacement detection probe according to claim 1, wherein said probe is formed of a piezoresistor. 4. The displacement detection probe according to claim 1, wherein said probe is formed of a platinum resistor. 5. The probe according to claim 1, further comprising: a resistance measuring unit for measuring a resistance value of a resistor of the probe, wherein the resistance is measured by the resistance measuring unit. A position measuring device, wherein a distance between the probe and a substrate facing the probe is determined based on a resistance value of the probe. 6. The probe according to claim 1, further comprising: a resistance measuring unit for measuring a resistance value of a resistor of the probe, wherein the resistance is measured by the resistance measuring unit. A position control device characterized in that a distance between the probe and a substrate facing the probe is controlled to be constant with reference to a resistance value of the probe.