CN-122015630-A - Surface morphology detection probe device and method based on active deflection compensation

CN122015630ACN 122015630 ACN122015630 ACN 122015630ACN-122015630-A

Abstract

The invention discloses a surface morphology detection probe device and method based on active deflection compensation, wherein the device comprises an upper displacement measurement module and a lower displacement measurement module which are used for measuring vertical displacement of a contact pin by adopting a split multipole plate capacitance sensor structure, an upper force balance control module and a lower force balance control module which form a second closed-loop control system with the upper displacement measurement module and the lower displacement measurement module and are used for controlling constant contact force between the contact pin and the surface of a sample, a front deflection measurement module and a rear deflection measurement module which are used for detecting deflection of the contact pin in the scanning direction, a front deflection control correction module and a front deflection measurement module and a rear deflection measurement module form a first closed-loop control system which are used for calculating correction moment required by a closed-loop control algorithm and applying reverse driving force to counteract deflection caused by shearing force, and the two closed-loop systems work cooperatively to realize control of the probe in the horizontal direction and the vertical direction. The invention solves the problems of track deviation caused by shearing force and insufficient signal-to-noise ratio of displacement measurement when the existing probe scans complex morphology.

Inventors

ZHANG SHIHAN
ZHAO HUI
Sun Yinzhuang

Assignees

广东芯衡科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260206

Claims (7)

1. The surface morphology detection probe device based on active deflection compensation is characterized by comprising a cantilever rod and a rotating shaft arranged on the cantilever rod, wherein the cantilever rod and the rotating shaft can synchronously rotate, a contact pin is arranged at one end, close to the rotating shaft, of the cantilever rod, and an up-down displacement measurement module, an up-down force balance control module, a front-back deflection measurement module and a front-back deflection control correction module are arranged at the other end of the cantilever rod; The front-back deflection measuring module is used for detecting deflection of the contact pin in the scanning direction; The front-back deflection control correction module receives signals output by the front-back deflection measurement module, calculates required correction moment through a closed-loop control algorithm, and applies reverse driving force to counteract deflection caused by shearing force; the vertical displacement measuring module adopts a split type multipole plate capacitive sensor structure to measure the vertical displacement of the contact pin; the upper and lower force balance control module receives signals output by the upper and lower displacement measurement module and controls the contact force between the contact pin and the surface of the sample to be constant; The front-back deflection measuring module and the front-back deflection control correction module form a first closed-loop control system, the upper-lower displacement measuring module and the upper-lower force balance control module form a second closed-loop control system, and the two closed-loop systems work cooperatively to realize the control of the probe in the horizontal direction and the vertical direction.
2. The surface morphology detection probe device based on active runout compensation according to claim 1, wherein the front and rear runout measurement module adopts a differential capacitance sensor structure, and comprises a cantilever rod, a middle polar plate fixed on the cantilever rod and fixed polar plates on two sides.
3. The active deflection compensation-based surface topography sensing probe device of claim 2, wherein the cantilever bar undergoes a slight deflection in the scanning direction under the action of tangential shear force when the stylus is scanned, resulting in a decrease in the gap between the middle plate and the one side fixed plate and an increase in the gap between the other side fixed plate, the differential change causing a change in the opposite direction in the two sets of capacitance values, the capacitance measurement circuit converting the capacitance change to a voltage or current signal output, the signal being proportional to the deflection amount.
4. The surface morphology detection probe device based on active deflection compensation according to claim 1, wherein the split type multi-polar plate capacitive sensor structure comprises a middle polar plate and a plurality of independent polar plates on two sides, an insulating layer is arranged between the polar plates, when the middle polar plate deflects along with a rotating shaft, two groups of similar triangle geometric relations are formed between the middle polar plate and the polar plates on two sides, and high signal-to-noise ratio measurement of vertical displacement of a contact pin is achieved by measuring multiple groups of capacitance changes and calculating by utilizing the similar triangle proportional relations.
5. The active runout compensation-based surface topography detection probe device of claim 1, wherein the actuator of the front and back runout control correction module employs a piezoelectric ceramic driver or a voice coil motor.
6. The active runout compensation-based surface topography detection probe device of claim 4, wherein the insulating layer is ceramic, polymer, or air gap.
7. A method of surface topography detection using the active runout compensation based surface topography detection probe device of any one of claims 1 to 6, the method comprising the steps of: Step 1, placing a sample to be measured on a measurement platform, and adjusting a probe to an initial position to enable a contact pin to be in light contact with the surface of the sample; Step 2, starting a front-back deflection measuring module and an up-down displacement measuring module, and establishing an initial reference; Step 3, starting a back deflection control correction module and an up-down force balance control module, wherein the front-back deflection control correction module corrects the deflection of the scanning direction in real time according to a deflection measurement signal, and the up-down force balance control module maintains constant contact force; Step 4, driving the sample platform or the probe to perform scanning movement, and continuously collecting vertical displacement data of the contact pin by the up-down displacement measuring module; and 5, after the scanning is finished, obtaining the appearance information of the sample surface through data processing.

Description

Surface morphology detection probe device and method based on active deflection compensation Technical Field The invention relates to the field of surface morphology detection, in particular to a surface morphology detection probe device and method based on active deflection compensation. Background In the fields of semiconductor manufacturing, precision machining, material science and the like, high-precision measurement of surface morphology is important. The contact type measuring equipment such as the step instrument and the like can detect the surface height change in real time by scanning the surface of the sample through the contact pin, and is widely applied to scenes such as film thickness measurement, step height detection, surface roughness evaluation and the like. The accuracy of the measurement directly influences the process control quality, namely the step height measurement error can cause the judgment misalignment of the thin film deposition process, the surface roughness deviation can influence the performance evaluation of the device, and the probe track deviation can cause the reconstruction distortion of the three-dimensional morphology. Therefore, ensuring the track precision and measurement stability of the probe in the scanning process is a key for improving the surface morphology detection reliability. In the actual measurement process, the probe structure faces two major technical challenges: First, when the stylus scans complex topography with a bevel or step, it is subject to tangential shear forces applied to the sample surface, resulting in unintended deflection of the probe in the scan direction (front-to-back direction). Such deflection can deviate the actual scanning trajectory of the stylus from a preset straight line path, introduce systematic horizontal position errors, and eventually lead to distortion of the measured surface topography. Particularly, when measuring high aspect ratio structures or steep steps, deflection errors caused by shearing force can reach hundreds of nanometers or even micrometers, and measurement accuracy is seriously affected. Second, the accuracy of the vertical displacement measurement of the probe directly determines the height resolution of the device. The signal-to-noise ratio of the sensor becomes a limiting factor under the nanoscale measurement requirements. Factors such as environmental vibration, electromagnetic interference, thermal noise and the like can introduce noise into weak displacement signals, and the repeatability and accuracy of measurement are reduced. At present, the existing surface morphology detection probes mainly adopt the following technical scheme: In terms of yaw control, conventional probe structures typically rely on mechanical damping or passive elastic elements to dampen yaw, lacking active detection and real-time compensation mechanisms. Some high-end devices are equipped with yaw detection sensors, but are only used for post-hoc data correction, and cannot dynamically eliminate the influence of shear force in the measurement process. The passive scheme has the advantages of delayed response when facing complex morphology, limited correction capability and difficulty in meeting the requirement of high-precision linear scanning. In terms of displacement measurement, the prior art mostly adopts an integral differential capacitive sensor structure. Commercial devices mainstream in the industry generally employ integral plates arranged one above the other to form differential capacitance pairs, and the vertical displacement of the probe is detected by measuring the capacitance change between the plates. Although the structure can realize the basic differential measurement function, the structure has the following defects that firstly, the whole polar plate area is larger, the influence of the edge effect and parasitic capacitance is obvious, the measurement sensitivity is reduced, secondly, the redundancy of a single differential pair is low, when the environmental interference or circuit noise is increased, the anti-interference capability is weaker, the measurement stability is reduced, thirdly, an effective geometric amplification mechanism is lacking, the capacitance variation is limited when the probe is subjected to tiny displacement, the signal-to-noise ratio is limited, and the nano-scale resolution requirement is difficult to meet. Disclosure of Invention Aiming at the problems, the invention provides a surface topography detection probe device and a surface topography detection method based on active deflection compensation, which aim to fundamentally solve the track deflection problem caused by shearing force and the signal-to-noise ratio bottleneck of displacement measurement so as to meet the increasing precision requirement of the advanced manufacturing field on the nano-scale surface topography detection. According to a first aspect of embodiments of the present disclosure, a surface topography det