CN113588798A - Real-time automatic focusing method of ultrasonic scanning microscope - Google Patents
Real-time automatic focusing method of ultrasonic scanning microscope Download PDFInfo
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- CN113588798A CN113588798A CN202110854539.3A CN202110854539A CN113588798A CN 113588798 A CN113588798 A CN 113588798A CN 202110854539 A CN202110854539 A CN 202110854539A CN 113588798 A CN113588798 A CN 113588798A
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- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
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Abstract
The invention discloses a real-time automatic focusing method of an ultrasonic scanning microscope, which calculates a focusing depth error by extracting the delay time of a first pulse echo peak value in ultrasonic echo data from a pulse trigger signal, controls an ultrasonic probe to move in the z direction according to a PID control algorithm and compensates the focusing depth error. After real-time automatic focusing is adopted, the warped sample can be imaged through one-time scanning, multiple traditional C scanning at different depths is not needed, the error of the focusing depth is small, and the warped sample is imaged uniformly.
Description
Technical Field
The invention belongs to the field of ultrasonic scanning microscopes, and particularly relates to a real-time automatic focusing method of an ultrasonic scanning microscope.
Background
An ultrasonic scanning microscope is a device for microscopic imaging of a sample using ultrasonic waves. Because the ultrasonic wave can penetrate through the surface of the sample, the ultrasonic scanning microscope can directly image the internal structure of the sample, and therefore, the ultrasonic scanning microscope is widely applied to the field of nondestructive testing, such as chip packaging defect detection, wafer bonding defect detection, composite material detection, welding detection and the like. The ultrasonic microscope focuses pulsed ultrasonic waves inside the sample, and the received pulse echoes contain material properties and height information of the sample. The section morphology and the three-dimensional morphology of the sample in all directions can be obtained by moving the probe to scan point by point in the horizontal plane above the sample.
C-scan is one of the most important detection modes of an ultrasonic scanning microscope, and can obtain a sectional image of a tested sample at a specific depth. The C scanning is to extract a peak value or a peak-to-peak value of a certain depth interval from the ultrasonic echo data as a pixel gray value of a pixel point of the plane, and after each pixel point in the plane is subjected to the processing, a whole C scanning image can be obtained. The higher the ultrasonic probe frequency of the ultrasonic microscope and the larger the numerical aperture, the higher the resolution, but the narrower the focusing depth range, and if a clear appearance of the internal structure of the sample is to be obtained, the depth of the target structure must be accurately focused.
For warped structure samples, such as thinned large area wafer samples, it is difficult for conventional high resolution ultrasonic scanning microscopes to obtain a complete internal structure in one scan because the target structure may not be at the same depth in the horizontal plane, but rather at a fixed distance from the curved surface. The traditional ultrasonic scanning microscope does not have a real-time automatic focusing function, and can obtain the complete morphology of a large-area warped sample only by scanning multiple different depths and splicing multiple layers of images, so that the detection speed is reduced, and the detection effect is difficult to guarantee.
Disclosure of Invention
The invention aims to provide a real-time automatic focusing method of an ultrasonic scanning microscope aiming at the defects of the prior art. The invention enables the high-resolution ultrasonic microscope to realize complete and rapid imaging of the warped sample.
The purpose of the invention is realized by the following technical scheme: a real-time automatic focusing method for ultrasonic scanning microscope includes manually focusing at initial scanning position, extracting the delay time of the first pulse echo peak value from pulse trigger signal at each scanning point, calculating focusing depth error, controlling the ultrasonic probe to move in Z direction according to PID control algorithm, correcting focusing error and real-time automatic focusing.
Further, manual focusing is performed at the initial scanning position, including:
moving the probe to an initial scanning position;
the height of the probe is manually adjusted, so that the ultrasonic waves are focused to a target focusing interface.
Further, the extracting the delay time of the first pulse echo peak from the pulse trigger signal at each scanning point comprises:
transmitting ultrasonic waves at each scanning point and receiving ultrasonic echo data;
and extracting the delay time of the first pulse echo peak value of the scanning point from the pulse trigger signal.
Further, according to the delay time, a depth of focus error is calculated, specifically, a depth of focus error e (i) of the ith scanning point is calculated according to the following formula:
e(i)＝k×[t(i)-t(1)]
k is half of the sound velocity of the medium where the sample is located, and t (i) and t (1) are the delay time of the first pulse echo peak value in the ultrasonic echo data of the ith scanning point and the initial scanning position from the pulse trigger signal respectively.
Further, according to a PID control algorithm, the z-direction movement of the ultrasonic probe is controlled, and the focusing error is corrected, specifically: controlling the probe of the ith scanning point to move towards the z direction by a distance dz (i) to realize the compensation of the focus depth error, wherein dz (i) is calculated by the following formula:
dz(i)＝dz(i-1)+kp×[e(i)-e(i-1)]+ki×e(i)+kd×[e(i)-2×e(i-1)+e(i-2)]
wherein kp, ki and kd are proportional, integral and differential coefficients of PID control, and dz (1) ═ dz (2) ═ 0, respectively.
Further, the method comprises the following steps:
s1, manual focusing is performed at the initial scanning position.
And S2, extracting the delay time of the first pulse echo peak value at the initial scanning position from the pulse trigger signal.
And S3, moving the probe to the next scanning position, transmitting ultrasonic pulses and acquiring echo data.
And S4, extracting the delay time of the first pulse echo peak value at the current position from the pulse trigger signal.
S5, a focus depth error and the like are calculated.
And S6, controlling the probe to move in the z direction according to a PID control algorithm, and correcting the focusing error.
S7, judging whether the scanning is finished, if not, repeating the steps S3 to S6; if so, the scanning of the entire sample is complete.
Compared with the prior art, the invention has the following characteristics:
(1) the invention can image the warped sample by one-time scanning, does not need multiple traditional C scanning at different depths, and has faster detection speed;
(2) the invention has small error of the focusing depth after compensation, and even imaging of the warping sample without splicing multiple layers of images.
Drawings
FIG. 1 is a schematic diagram of the working principle of an ultrasonic scanning microscope provided by the present invention;
FIG. 2 is a flow chart of a real-time auto-focusing method for an ultrasonic scanning microscope according to the present invention;
FIG. 3 is a schematic diagram of ultrasonic echo data and pulse trigger signals in accordance with the present invention;
FIG. 4 is a schematic diagram of the focus depth error before and after real-time auto-focusing according to an embodiment of the present invention;
in the figure: an ultrasonic probe 1, ultrasonic waves 2, a sample upper surface 3 and a target focusing interface 4.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and those skilled in the art will be able to make similar modifications without departing from the spirit of the application and it is therefore not intended to be limited to the embodiments disclosed below.
Referring to fig. 1, the present invention relates to a real-time auto-focusing method for an ultrasonic scanning microscope, and is mainly directed to a warped sample or an inclined sample, wherein the upper surface of the warped sample or the inclined sample is a non-horizontal surface, and the relative distance between a target detection structure and the upper surface is fixed. In particular, the sample may be a warped wafer, a squeezed sample, a flexible composite, a chip placed with a tilt, or the like. The ultrasound probe 1 emits ultrasound waves 2 through the sample upper surface 3 focused to a target focus interface 4.
Referring to fig. 2, the method for real-time auto-focusing of an ultrasonic scanning microscope according to the present invention calculates a focusing depth error by extracting a delay time from a first pulse echo peak value in ultrasonic echo data to a pulse trigger signal, and controls an ultrasonic probe to move in a z direction according to a PID control algorithm to compensate the focusing depth error. Parameter calibration is completed at the initial scanning position, and manual focusing is performed to the depth of a target position, so that real-time automatic focusing can be performed at subsequent coordinate points, and a focusing depth error caused by sample warping is inhibited. The method specifically comprises the following steps:
in step S1, manual focusing is performed at the initial scanning position.
Specifically, the probe of the ultrasonic microscope is moved to a position above the initial scanning position of the sample, the height of the ultrasonic probe is manually adjusted, the ultrasonic wave is focused to a target focusing interface, and data acquisition is started.
Step S2, after focusing at the initial scanning position, transmits an ultrasonic wave and receives ultrasonic echo data, and extracts the delay time t (1) from the first pulse echo peak to the pulse trigger signal.
Specifically, referring to fig. 3, in the ultrasonic echo data, the first pulse echo is an echo signal of the upper surface of the sample, and the delay time t from the peak of the first pulse echo to the pulse trigger signal can be used to calculate the distance d between the upper surface of the sample and the ultrasonic probe, where d is k × t (1), where k is half of the sound velocity in the medium where the sample is located.
And step S3, moving the probe to the next scanning position, transmitting ultrasonic pulses and collecting echo data.
Specifically, the probe is moved to the next adjacent scanning position, the coordinate position is recorded as the position of the ith scanning point, and echo data are acquired.
In step S4, the delay time between the first pulse echo peak and the pulse trigger signal at the current position is extracted.
Specifically, the delay time t (i) of the first pulse echo peak from the pulse trigger signal is extracted from the ultrasonic echo data of the ith scanning point.
In step S5, a depth of focus error is calculated.
Specifically, according to the delay time t (i) of the ith scanning point, the focus depth error e (i) is calculated, and the calculation formula is e (i) × [ t (i) — t (1) ].
And step S6, controlling the probe to move in the z direction according to a PID control algorithm, and correcting the focusing error.
Specifically, the upper computer runs a PID control algorithm, controls the probe to move a certain distance dz (i) towards the z-axis direction, and corrects the focusing error. Specifically, dz (i) is calculated as:
dz(i)＝dz(i-1)+kp×[e(i)-e(i-1)]+ki×e(i)+kd×[e(i)-2×e(i-1)+e(i-2)]
and dz (i-1) is the z-direction moving distance of the probe at the i-1 th scanning point, e (i-1) and e (i-2) are focus depth errors of the i-1 th scanning point and the i-2 th scanning point respectively, and kp, ki and kd are proportional, integral and differential coefficients controlled by PID respectively. Note that dz (1) and dz (2) are forced to 0, and need not be calculated according to the above formula.
Step S7, judging whether the scanning is finished, if not, repeating the steps S3 to S6; if so, the scanning of the entire sample is complete.
Specifically, the condition of determining whether scanning is finished is that whether the current value i is equal to the preset total number of scanning points, if so, scanning is finished, if not, scanning is not finished, the loop is entered again, and the value i is increased by 1.
Referring to fig. 4, an embodiment of the present invention is a sample with a downward recess, comparing the effect of the sample before and after the real-time auto-focusing method is performed. In this embodiment, kp is 1, ki is 0.01, and kd is 0. It can be seen that, before the real-time automatic focusing is adopted, the error of the focusing depth is large, after the real-time automatic focusing is adopted, the error is obviously inhibited, and the absolute value of the maximum error is only 4% before the automatic focusing.
Claims (6)
1. A real-time automatic focusing method for an ultrasonic scanning microscope is characterized in that manual focusing is carried out at an initial scanning position, the delay time of a first pulse echo peak value of each scanning point from a pulse trigger signal is extracted, a focusing depth error is calculated, an ultrasonic probe is controlled to move in the z direction according to a PID control algorithm, the focusing error is corrected, and real-time automatic focusing is carried out.
2. The real-time auto-focusing method for the ultrasonic scanning microscope according to claim 1, wherein the manual focusing at the initial scanning position comprises:
moving the probe to an initial scanning position;
the height of the probe is manually adjusted, so that the ultrasonic waves are focused to a target focusing interface.
3. The real-time automatic focusing method for the ultrasonic scanning microscope as claimed in claim 1, wherein the step of extracting the delay time of the first pulse echo peak value of each scanning point from the pulse trigger signal comprises the following steps:
transmitting ultrasonic waves at each scanning point and receiving ultrasonic echo data;
and extracting the delay time of the first pulse echo peak value of the scanning point from the pulse trigger signal.
4. The real-time auto-focusing method for the ultrasonic scanning microscope according to claim 1, wherein the delay time is used to calculate the depth of focus error, specifically, the depth of focus error e (i) of the ith scanning point is calculated by the following formula:
e(i)＝k×[t(i)-t(1)]
k is half of the sound velocity of the medium where the sample is located, and t (i) and t (1) are the delay time of the first pulse echo peak value in the ultrasonic echo data of the ith scanning point and the initial scanning position from the pulse trigger signal respectively.
5. The real-time auto-focusing method for the ultrasonic scanning microscope according to claim 1, wherein the z-direction movement of the ultrasonic probe is controlled according to a PID control algorithm to correct the focusing error, specifically: controlling the probe of the ith scanning point to move towards the z direction by a distance dz (i) to realize the compensation of the focus depth error, wherein dz (i) is calculated by the following formula:
dz(i)＝dz(i-1)+kp×[e(i)-e(i-1)]+ki×e(i)+kd×[e(i)-2×e(i-1)+e(i-2)]
wherein kp, ki and kd are proportional, integral and differential coefficients of PID control, and dz (1) ═ dz (2) ═ 0, respectively.
6. The real-time automatic focusing method for the ultrasonic scanning microscope according to claim 1, comprising the following steps:
s1, manual focusing is performed at the initial scanning position.
And S2, extracting the delay time of the first pulse echo peak value at the initial scanning position from the pulse trigger signal.
And S3, moving the probe to the next scanning position, transmitting ultrasonic pulses and acquiring echo data.
And S4, extracting the delay time of the first pulse echo peak value at the current position from the pulse trigger signal.
S5, a focus depth error and the like are calculated.
And S6, controlling the probe to move in the z direction according to a PID control algorithm, and correcting the focusing error.
S7, judging whether the scanning is finished, if not, repeating the steps S3 to S6; if so, the scanning of the entire sample is complete.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002334678A (en) * | 2001-05-09 | 2002-11-22 | Jeol Ltd | Auto-focus method in scanned type charged particle beam device and scanned type charged particle beam device |
| JP2003107059A (en) * | 2001-09-27 | 2003-04-09 | Hitachi Kenki Fine Tech Co Ltd | Ultrasonic image apparatus and measurement method thereof |
| CN109276229A (en) * | 2018-08-15 | 2019-01-29 | 华中科技大学苏州脑空间信息研究院 | A kind of rapid focus system and method for opto-acoustic microscopic imaging |
| CN110118822A (en) * | 2018-02-07 | 2019-08-13 | 株式会社东芝 | Ultrasonic flaw detecting device and defect detection on ultrasonic basis |
| CN111007661A (en) * | 2019-12-02 | 2020-04-14 | 湖南国科智瞳科技有限公司 | Microscopic image automatic focusing method and device based on deep learning |
| CN111741210A (en) * | 2019-03-25 | 2020-10-02 | 高新兴科技集团股份有限公司 | Fast automatic focusing method and device based on fixed scene |
| CN112415735A (en) * | 2020-03-16 | 2021-02-26 | 中国科学院深圳先进技术研究院 | Real-time automatic focusing system for microscope |
| CN112630306A (en) * | 2020-08-20 | 2021-04-09 | 中国科学院大学 | Automatic focusing method and system based on point focusing transducer of ultrasonic microscope |
-
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- 2021-07-28 CN CN202110854539.3A patent/CN113588798B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002334678A (en) * | 2001-05-09 | 2002-11-22 | Jeol Ltd | Auto-focus method in scanned type charged particle beam device and scanned type charged particle beam device |
| JP2003107059A (en) * | 2001-09-27 | 2003-04-09 | Hitachi Kenki Fine Tech Co Ltd | Ultrasonic image apparatus and measurement method thereof |
| CN110118822A (en) * | 2018-02-07 | 2019-08-13 | 株式会社东芝 | Ultrasonic flaw detecting device and defect detection on ultrasonic basis |
| CN109276229A (en) * | 2018-08-15 | 2019-01-29 | 华中科技大学苏州脑空间信息研究院 | A kind of rapid focus system and method for opto-acoustic microscopic imaging |
| CN111741210A (en) * | 2019-03-25 | 2020-10-02 | 高新兴科技集团股份有限公司 | Fast automatic focusing method and device based on fixed scene |
| CN111007661A (en) * | 2019-12-02 | 2020-04-14 | 湖南国科智瞳科技有限公司 | Microscopic image automatic focusing method and device based on deep learning |
| CN112415735A (en) * | 2020-03-16 | 2021-02-26 | 中国科学院深圳先进技术研究院 | Real-time automatic focusing system for microscope |
| CN112630306A (en) * | 2020-08-20 | 2021-04-09 | 中国科学院大学 | Automatic focusing method and system based on point focusing transducer of ultrasonic microscope |
Non-Patent Citations (1)
| Title |
|---|
| 周丽平;孙志峻;张泉;: "显微视觉系统的自动聚焦及控制", 光学精密工程, no. 03 * |
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