Contact type surface topography measuring device

Abstract

The utility model discloses a contact type surface topography measuring device. The device comprises a test board, a measuring module and an upper computer. The measuring module comprises a probe, a pressure applying assembly, a capacitance sensor and a data processing circuit. The probe is connected with the pressure applying assembly, a probe head of the probe is perpendicular to the placing plane of the test board, and the pressure applying assembly provides pressure for the probe to press the placing plane, so that the probe head of the probe is kept in contact with the surface of the wafer to be tested; the capacitive sensor comprises a movable polar plate and a static polar plate; the movable polar plate is connected with the probe and can move relative to the static polar plate along the extension direction of the probe head along with the probe; the data processing circuit is respectively connected with the movable polar plate and the static polar plate, and the data processing circuit can generate digital quantity sampling data according to the capacitance value between the movable polar plate and the static polar plate. The upper computer is connected with the data processing circuit, and the surface appearance of the wafer to be measured is restored according to the digital quantity sampling data, so that the surface appearance of the wafer is measured by using the capacitive sensor, and the measurement accuracy is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to surface topography measurement field especially relates to a contact type surface topography measurement device. BACKGROUND

[0002] With the development level of industrial automation and semiconductor equipment field unceasing enhancement, the production flow is more and more high to object surface flatness and topography detection precision requirement, and traditional manual measurement method has been difficult to satisfy the pursuit of high-precision measurement of people.

[0003] The main means of object surface detection at present contains contact type detection and non-contact type detection, but, the whole machine equipment cost of existing non-contact type detection is extremely high, and the detection precision of contact type detection technology is low, which limits the rapid development of semiconductor industry. SUMMARY

[0004] The utility model provides a contact type surface topography measurement device to improve surface topography measurement precision.

[0005] The utility model provides a contact type surface topography measurement device, this contact type surface topography measurement device includes test table, measurement module and host computer;

[0006] The test table is used to place the wafer to be measured;

[0007] The measurement module includes probe, pressure assembly, capacitance sensor and data processing circuit, the probe is mechanically connected with the pressure assembly, the needle head of the probe is vertically arranged with the placement plane of the test table, the pressure assembly provides the pressure to the probe to the placement plane, makes the needle head of the probe keep contact with the surface of the wafer to be measured, the capacitance sensor includes moving plate and static plate, the moving plate is mechanically connected with the probe, and the moving plate can correspond with the movement stroke of the probe along the needle head extension direction, relative to the corresponding movement of the static plate, the data processing circuit is electrically connected with the capacitance sensor, and the data processing circuit can generate digital sampling data according to the capacitance value of the capacitance sensor;

[0008] The host computer is communicated with the data processing circuit, and the surface topography of the wafer to be measured is restored according to the digital sampling data.

[0009] Optionally, the capacitance sensor includes differential capacitance sensor.

[0010] Optionally, the data processing circuit includes capacitance voltage conversion subcircuit and analog-digital conversion chip.

[0011] The capacitive voltage conversion sub-circuit is electrically connected with the movable electrode plate and the static electrode plate respectively; the analog-digital conversion chip is electrically connected with the capacitive voltage conversion sub-circuit and is also in communication connection with the upper computer.

[0012] Optionally, the capacitive voltage conversion sub-circuit comprises a differential bus transceiver and an operational amplifier.

[0013] Optionally, the data processing circuit further comprises an operational amplification sub-circuit, which is arranged between the capacitive voltage conversion sub-circuit and the analog-digital conversion chip.

[0014] Optionally, the data processing circuit further comprises a radio frequency connector, which is connected with the output end of the operational amplification sub-circuit.

[0015] Optionally, the capacitive sensor comprises a single capacitive sensor.

[0016] Optionally, the contact surface topography measuring device further comprises a first motor, which is mechanically connected with the test table and drives the wafer to be measured on the test table to rotate and / or displace relative to the probe.

[0017] Optionally, the contact surface topography measuring device further comprises a second motor, which is mechanically connected with the measuring module and drives the probe to rotate and / or displace relative to the wafer to be measured on the test platform.

[0018] Optionally, the test table is an air floating platform.

[0019] The contact surface topography measuring device provided by the present application generates digital sampling data according to the capacitance value between the movable electrode plate and the static electrode plate through the data processing circuit, restores the surface topography of the wafer to be measured according to the digital sampling data, realizes the measurement of the surface topography of the wafer by the capacitive sensor, and improves the measurement accuracy.

[0020] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0022] Figure 1A contact type surface topography measuring device composition schematic diagram is provided for the embodiment of the utility model;

[0023] Figure 2 A data processing circuit composition schematic diagram is provided for the embodiment of the utility model;

[0024] Figure 3 A capacitor voltage conversion subcircuit circuit schematic diagram is provided for the embodiment of the utility model;

[0025] Figure 4 A differential capacitor sensor structure schematic diagram is provided for the embodiment of the utility model;

[0026] Figure 5 Another data processing circuit composition schematic diagram is provided for the embodiment of the utility model;

[0027] Figure 6 Another contact type surface topography measuring device composition schematic diagram is provided for the embodiment of the utility model;

[0028] Figure 7 Still another contact type surface topography measuring device composition schematic diagram is provided for the embodiment of the utility model;

[0029] Figure 8 A local schematic diagram of the measured wafer surface topography restored by the host computer is provided for the embodiment of the utility model. DETAILED DESCRIPTION

[0030] In order to make the person in the art better understand the utility model scheme, the technical scheme in the embodiment of the utility model will be described clearly and completely in the following with the drawings in the embodiment of the utility model, obviously, the described embodiment is only a part of the embodiment of the utility model, rather than all the embodiments. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of the utility model protection.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] To address the problems mentioned in the background art, this utility model provides a contact-type surface topography measuring device, the composition of which is shown in the schematic diagram below. Figure 1 As shown, the contact surface morphology measurement device 100 includes a test stage 101, a measurement module 102, and a host computer 103. The test stage 101 is used to place the wafer to be tested. The measurement module 102 includes a probe 104, a pressure application component 105, a capacitance sensor 106, and a data processing circuit 107. The probe 104 is mechanically connected to the pressure application component 105. The tip of the probe 104 is perpendicular to the placement plane of the test stage 101. The pressure application component 105 provides pressure to the probe 104 against the placement plane, keeping the tip of the probe 104 in contact with the surface of the wafer under test. The capacitance sensor 106 includes a moving electrode b and a stationary electrode a. The moving electrode b is mechanically connected to the probe 104 and can move relative to the stationary electrode a as the probe 104 moves along its extension direction. The data processing circuit 107 is electrically connected to at least one of the moving electrode b and the stationary electrode a. The data processing circuit 107 can generate digital sampling data based on the capacitance value between the moving electrode b and the stationary electrode a. The host computer 103 is communicatively connected to the data processing circuit 107 and reconstructs the surface morphology of the wafer under test based on the digital sampling data.

[0033] Specifically, the test stage 101 refers to a placement stage used to support the wafer under test. During the measurement process, it can provide a placement plane for the wafer under test. In some embodiments, the movable components of the test stage 101 can also drive the placement plane and the wafer under test on it to move relative to the probe 104. For example, the placement plane provided by the test stage 101 can be parallel to the horizontal plane. With the movable components mechanically connected to the test stage 101, it moves horizontally relative to the probe 104 together with the wafer under test on it.

[0034] Probe 104 refers to a measuring needle that directly contacts the surface of the wafer being measured. During the measurement process, the tip of probe 104 contacts the surface of the wafer being measured under the pressure provided by the pressure application component 105, and slides on the surface of the wafer being measured as probe 104 moves relative to the wafer being measured. Probe 104 will be displaced in a direction perpendicular to the placement plane according to the morphology of the contacted surface. For example, during the test process with probe 104 on top and wafer being measured below, if probe 104 slides to a depression on the surface of the wafer being measured, probe 104 will be displaced downward; if probe 104 slides to a protrusion on the surface of the wafer being measured, probe 104 will be displaced upward.

[0035] The pressure application component 105 can both provide pressure to the probe 104 and limit the direction and stroke of the probe 104. Exemplarily, the pressure application component 105 may include an elastic force supply structure and / or an electromagnetic force supply structure. The elastic element in the elastic force supply structure can be mechanically connected to the root of the probe 104. During testing, the elastic element is compressed, thereby providing pressure to the probe 104 against the surface of the wafer under test based on the elastic force of the elastic element. The elastic element can be a cross spring. The two ends of the electromagnetic coil in the electromagnetic force supply structure are connected to a controllable current source. The pressure-applying metal element in the electromagnetic force supply structure passes through the coil and is mechanically connected to the root of the probe 104. During testing, the energized electromagnetic coil can provide induced electromagnetic force to the pressure-applying metal element, causing the tip of the probe 104 connected to it to press against the surface of the wafer under test and maintain contact with the surface of the wafer under test.

[0036] The capacitive sensor 106 is a displacement sensor that detects the displacement of the probe 104 by utilizing changes in capacitance. Its core principle is based on the capacitance formula C = εA / d, where C is capacitance, ε is dielectric constant, A is electrode area, and d is electrode spacing. Exemplarily, the capacitive sensor 106 can be a cylindrical capacitive sensor, a surface capacitive sensor, a single-capacitive sensor, or a differential capacitive sensor. When the capacitive sensor 106 is a single-capacitive sensor (not shown in the figure), the stationary electrode a is on top and the moving electrode b is on the bottom. If the probe 104 slides to a protrusion on the surface of the wafer being measured, the root of the probe 104 correspondingly drives the moving electrode b of the capacitive sensor 106 away from the stationary electrode a, reducing the electrode spacing and thus increasing the capacitance. In other words, the capacitance of the single-capacitive sensor can reflect the displacement of the probe 104 in the direction perpendicular to the plane where it is placed. When the capacitance sensor 106 is a differential capacitance sensor (as shown in the figure), the moving plate b is positioned between the two stationary plates a. If the probe 104 slides to the protrusion on the surface of the wafer being measured, the root of the probe 104 correspondingly drives the moving plate b of the capacitance sensor 106 to move closer to the upper stationary plate a, causing a change in the capacitance difference between the two capacitors formed by the moving plate b and the two stationary plates a. The data processing circuit 107 refers to the processing circuit for capacitance change parameters, capable of detecting capacitance change parameters and generating corresponding digital sampling data, which is then transmitted to the host computer 103. For example, the data processing circuit 107 can be connected to the two stationary plates a of the differential capacitance sensor respectively. By measuring the voltage or charge difference on the two stationary plates a, the capacitance difference can be indirectly measured. The data processing circuit 107 may include an operational amplifier circuit and an analog-to-digital converter circuit.

[0037] The host computer 103 is a device for storing, querying and displaying measurement results. It can restore and display the surface morphology of the wafer under test according to the sliding trajectory of the probe 104 based on the digital sampling data transmitted by the data processing circuit 107. For example, the host computer 103 includes a computer and a display.

[0038] Figure 2 This is a schematic diagram of the composition of a data processing circuit according to an embodiment of the present invention. Figure 3 This is a circuit diagram of a capacitor voltage conversion sub-circuit proposed in an embodiment of the present invention, combined with... Figure 1 , Figure 2 and Figure 3 Another embodiment of this application provides another possible capacitance sensor 106, which includes a differential capacitance sensor. Another possible data processing circuit 107 includes a capacitance-to-voltage conversion sub-circuit 201 and an analog-to-digital converter chip 202. The capacitance-to-voltage conversion sub-circuit 201 is electrically connected to the moving electrode b and the stationary electrode a, respectively; the analog-to-digital converter chip 202 is electrically connected to the capacitance-to-voltage conversion sub-circuit 201 and also has a communicative connection with the host computer 103.

[0039] Specifically, Figure 4 This is a schematic diagram of the structure of a differential capacitance sensor provided in an embodiment of the present invention, combined with... Figures 1-4 A differential capacitance sensor is a sensor based on the principle of capacitance change. It consists of two stationary plates (a) and a moving plate (b) positioned between them. The differential capacitance sensor connects two capacitors in parallel to form an upper capacitor C. m and a lower capacitor C n The common plate between the two capacitors is the moving plate b. When the moving plate b moves up and down following the probe 104, the upper capacitor C... m and lower capacitor C n The capacitance value changes according to the corresponding electrode spacing d. Simultaneously, the charge on the upper and lower capacitors also transfers with the displacement of the moving plate b. The charges of the upper and lower capacitors are connected to the data processing circuit 107 using wires. After analysis and conversion by the data processing circuit 107, the charge is converted into a digital signal that can be recognized by the host computer 103. The host computer 103 can calculate the displacement of the moving plate b in the differential capacitance sensor based on the digital signal, thereby determining the displacement of the probe 104. For example, before the measurement begins, the probe 104 is in its initial position and the tip contacts the surface of the wafer being measured. At this time, the moving plate b of the differential capacitance sensor is located in the exact middle position between the two stationary plates a. During the measurement process, the upper capacitance C formed by the two stationary plates a with each stationary plate a is measured. m and lower capacitor C n The difference between the values ​​can determine the positional change of probe 104.

[0040] The capacitor-to-voltage conversion sub-circuit 201 refers to the conversion circuit and related components that convert capacitance change parameters into voltage signals. For example, the capacitor-to-voltage conversion sub-circuit 201 may include a differential bus transceiver 301 and an operational amplifier 302. The differential bus transceiver 301 is a key device for differential signal transmission. Its two input terminals are respectively connected to two capacitors in the differential capacitance sensor. The differential bus transceiver 301 can determine the logic state of the capacitance sensor 106 based on the voltage difference between the two capacitors, thereby generating a corresponding fluctuating voltage signal. For example, the differential bus transceiver 301 can be a differential bus transceiver of model LT1793IS8#PBF, which features high-speed transmission, strong anti-interference capability, and high reliability, making it suitable for high-precision measurement fields such as wafer surface topography measurement. Operational amplifier 302 is connected to the output of differential bus transceiver 301 to perform operational amplification on the fluctuating voltage output by differential bus transceiver 301. For example, operational amplifier 302 can be an operational amplifier of model TLE2071CD, which has the characteristics of low noise, high speed and low power consumption. It can amplify and filter the analog voltage signal output by differential bus transceiver 301 as the input buffer of the subsequent analog-to-digital converter chip 202.

[0041] An operational amplifier sub-circuit 203 may also be included between the analog-to-digital converter chip 202 and the capacitor voltage conversion sub-circuit 201. The operational amplifier sub-circuit 203 may include two operational amplifier circuits: one for filtering and further amplifying voltage signals greater than a preset potential in the voltage signal output from the preceding capacitor voltage conversion sub-circuit 201, and the other for filtering and further amplifying voltage signals less than a preset potential in the voltage signal output from the preceding capacitor voltage conversion sub-circuit 201. The two amplified signals are respectively input to the analog-to-digital converter chip 202. The analog-to-digital converter chip 202 is an integrated circuit that converts analog signals into digital signals. It converts continuous analog signals into discrete digital signals through three steps: sampling, quantization, and encoding. For example, the analog-to-digital converter chip 202 may be a CS5361-KSZ model. For example, the data processing circuit 107 may be integrated into a signal processing board.

[0042] The capacitance sensor and data processing circuit provided in this embodiment utilize a differential capacitance sensor to sample, analyze, and process the probe displacement. The differential capacitance sensor has high sampling accuracy, which, combined with the subsequent analysis and processing circuit, further improves the measurement accuracy of the device.

[0043] Figure 5 This is a schematic diagram of another data processing circuit proposed in an embodiment of the present invention, with reference to... Figure 5Another embodiment of this application provides yet another possible data processing circuit 107, which further includes an RF connector 401 connected to the output of the operational amplifier sub-circuit 203.

[0044] Specifically, the RF connector 401 refers to a dedicated connector for connecting RF cables or devices. For example, the RF connector 401 can be an RF connector of model KH-IPEX-K501-29. The RF connector 401 can connect to wireless communication devices, realizing a wireless connection between the data processing circuit 107 and the host computer 103, so that the contact surface topography measurement device 100 is not constrained by too many wires, improving the convenience of the device.

[0045] Figure 6 This is a schematic diagram of another contact surface morphology measuring device provided in an embodiment of the present invention, with reference to... Figure 6 Another embodiment of this application provides another contact surface morphology measurement device 100, which further includes at least one first motor 501. The first motor 501 is mechanically connected to the test stage 101 and drives the wafer under test on the test stage 101 to rotate and / or displace relative to the probe 104.

[0046] Specifically, the first motor 501 refers to a motor mounted on the test stage 101. The first motor 501 can drive at least some components of the test stage 101 to move, thereby causing the wafer under test on the test stage 101 to rotate and / or shift relative to the probe 104. For example, the first motor 501 may include a linear motor and / or a rotary motor. Three first motors 501 may be provided, each driving the wafer under test on the test stage 101 to move linearly along the X, Y, and Z axes of a three-dimensional coordinate system, enabling the probe 104 to perform omnidirectional testing of the wafer under test. Two first motors 501 can also drive the wafer under test on the test stage 101 to move linearly along the x and y axes of a three-dimensional coordinate system, while the third first motor 501 can drive the wafer under test on the test stage 101 to rotate around the R axis of a three-dimensional coordinate system.

[0047] Optionally, Figure 7 A schematic diagram of another contact surface morphology measuring device provided in this embodiment of the present invention is shown below. Figure 7 Another embodiment of this application provides a contact surface morphology measurement device 100, which further includes a second motor 502. The second motor 502 is mechanically connected to the measurement module 102 and drives the probe 104 to rotate and / or displace relative to the wafer under test on the test platform.

[0048] Specifically, the second motor 502 refers to a motor mounted on the measurement module 102. The second motor 502 can drive the probe 104, pressure application component 105, and capacitance sensor 106 within the measurement module 102 to move together, thereby allowing the probe 104 to rotate and / or displace relative to the wafer under test on the test stage 101. For example, the second motor 502 may include a linear motor and / or a rotary motor. The measurement module 102 may have three second motors 502, each driving the probe 104 to move linearly along the x, y, and z axes of a three-dimensional coordinate system, enabling omnidirectional testing of the wafer under test. Additionally, two second motors 502 can also drive the probe 104 to move linearly along the x and y axes of a three-dimensional coordinate system, while the third second motor 502 can drive the probe 104 to rotate around the r-axis of a three-dimensional coordinate system.

[0049] For example, Figure 8 This is a partial schematic diagram of the surface morphology of the wafer under test restored by a host computer, provided in an embodiment of this utility model. Figure 7 and 8 The test platform 101 is an air-float platform. The wafer under test is placed on the placement plane provided by the air-float platform to ensure the stability of the wafer during the test. The wafer under test is placed on the air-float platform, and the two first motors 501 connected to the air-float platform move to drive the wafer under test along the X and Y axes, adjusting the angle, orientation, and position of the wafer under test relative to the probe 104 in the horizontal direction. After the measurement begins, the second motor 502 on the measurement module 102 drives the probe 104 to move downwards along the Z axis (the Z axis is perpendicular to the placement plane). When the probe 104 contacts the object under test, the second motor 502 stops running. After the initial position of the probe 104 and the wafer under test is determined, the first motor 501 on the test platform 101 drives the air-float platform to begin displacement. At this time, the probe 104 slides on the surface of the object under test, simultaneously causing a capacitance difference between the two capacitors of the capacitance sensor 106. Ultimately, the change in capacitance difference is transmitted to the signal processing board via wires. The signal processing board then performs secondary data processing on the data processing circuit 107. Finally, the host computer 103 displays the result on the display interface. Figure 8 A schematic diagram of the surface morphology shown.

[0050] The contact surface morphology measurement device provided in this embodiment utilizes a first motor and a second motor to achieve accurate control of the initial position and measurement position of the probe and the wafer under test, further improving the accuracy of the measurement.

[0051] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A contact surface topography measuring device, characterized in that The application relates to a wafer surface topography testing device. The device comprises a testing table, a measuring module and an upper computer. The testing table is used for placing a wafer to be measured. The measuring module comprises a probe, a pressure applying assembly, a capacitive sensor and a data processing circuit. The probe is mechanically connected with the pressure applying assembly.

2. The apparatus of claim 1, wherein, The needle of the probe is vertically arranged on the placing plane of the testing table.

3. The apparatus of claim 2, wherein, The pressure applying assembly provides pressure for the probe to press against the placing plane, so that the needle of the probe keeps in contact with the surface of the wafer to be measured. The capacitive sensor comprises a moving electrode plate and a static electrode plate.

4. The apparatus of claim 3, wherein, The moving electrode plate is mechanically connected with the probe.

5. The apparatus of claim 3, wherein, The moving electrode plate can correspondingly move relative to the static electrode plate along the movement stroke of the probe in the extending direction of the needle.

6. The apparatus of claim 5, wherein, The data processing circuit is electrically connected with the capacitive sensor.

7. The apparatus of claim 1, wherein, The data processing circuit can generate digital sampling data according to the capacitance value of the capacitive sensor.

8. The apparatus of claim 1, wherein, The upper computer is in communication connection with the data processing circuit. The upper computer restores the surface topography of the wafer to be measured according to the digital sampling data.

9. The apparatus of claim 8, wherein, The capacitive sensor is a differential capacitive sensor. The data processing circuit comprises a capacitive voltage conversion sub-circuit and an analog-digital conversion chip.

10. The apparatus of claim 1, wherein, The capacitive voltage conversion sub-circuit is electrically connected with the moving electrode plate and the static electrode plate respectively. The analog-digital conversion chip is electrically connected with the capacitive voltage conversion sub-circuit and is in communication connection with the upper computer. The capacitive voltage conversion sub-circuit comprises a differential bus transceiver and an operational amplifier. The data processing circuit further comprises an operational amplification sub-circuit. The operational amplification sub-circuit is arranged between the capacitive voltage conversion sub-circuit and the analog-digital conversion chip. The data processing circuit further comprises a radio frequency connector. The radio frequency connector is connected with the output end of the operational amplification sub-circuit. The capacitive sensor is a single capacitive sensor. The application further relates to a wafer surface topography testing device. The device comprises a first motor. The first motor is mechanically connected with the testing table. The first motor drives the wafer to be measured on the testing table to rotate and / or displace relative to the probe. The device further comprises a second motor. The second motor is mechanically connected with the measuring module. The second motor drives the probe to rotate and / or displace relative to the wafer to be measured on the testing table. The testing table is an air floating platform.

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