Method for operating scanning acoustic microscope and scanning acoustic microscope

Abstract

The invention relates to a method for operating a scanning acoustic microscope, in particular an ultrasonic scanning microscope, in which a sample is scanned in an X-Y plane by means of a transducer unit (10), in particular with one or more transducer elements (1, 2, 3, 4, 12, 14), each comprising a transducer (20) and a lens (21, 22), wherein the transducer unit (10) is moved in the X-direction for linear scanning of the sample, and wherein the transducer unit (10) is displaced in the Y-direction by a displacement increment (U, W) after one or more linear scans of the sample by the transducer unit (10), and wherein the magnitude of the displacement increment (U, W) of the transducer unit (10) in the Y-direction is varied for the scanning of the sample, wherein in particular, after the displacement of the transducer unit (10) in the Y-direction, at least one further linear scan of the sample is performed in the Y-direction by the transducer unit (10).

Description

Technical Field

[0001] The present invention relates to a method for operating a scanning acoustic microscope (particularly an ultrasonic scanning microscope), and a scanning acoustic microscope (particularly an ultrasonic scanning microscope). Background Art

[0002] Ultrasound microscopy or acoustic microscopy, also known as scanning acoustic microscopy (SAM), is used to scan a sample by ultrasound in a scanning method and process the reflected sound waves to generate an image of the sample structure therefrom.

[0003] Ultrasound microscopes therefore have ultrasound heads, which are also referred to as transducer heads. The ultrasound head therefore consists of an acoustic lens and a sound converter (transducer) connected thereto.

[0004] In the case of acoustic microscopy examinations, water is used as a coupling medium between the acoustic transducer and the sample to be examined in order to obtain a good transmission of the acoustic waves emitted by the transducer to the sample. For this purpose, a coupling medium with good properties for sound conduction is required.

[0005] In ultrasonic microscopy operating in the frequency range of 1 MHz to 5 GHz, the sample is usually immersed in a water tank and placed on a sample holder, and the sample is examined by the ultrasonic microscope in an immersed state. In another method, a water jet is used formed between the sound transducer and the sample to ensure a good sound connection into the sample.

[0006] Ultrasound microscopy is known from the prior art, in which a sample is scanned by ultrasound and the sound waves that pass through or are reflected are processed to generate an image therefrom. The imaging is non-destructive, wherein information about the internal structure of the sample is thereby obtained. Materials, electronic components, etc. can be analyzed or monitored by means of the images obtained in the scanning method.

[0007] Furthermore, in acoustic microscopy, a multi-channel transducer is used in which a large number of individual elements with a fixed focal length are arranged adjacent to each other. The pixel size in the Y direction (i.e., perpendicular to the scanning direction in the X direction) thus corresponds to the distance of the individual transducer elements from each other. In the case of using such a multi-channel transducer, a number of parallel linear scan lines are recorded simultaneously corresponding to the number of transducer elements. In the case of the transducer elements of a multi-channel transducer, the distance of the individual elements from each other is constant and cannot be changed, whereby the height of the line of the linear scan is fixed and the pixel size in the Y direction (i.e., perpendicular to the scanning direction in the X direction) always corresponds to the width of the individual transducer elements and is constant. Since the size of the individual elements in the Y direction (i.e., perpendicular to the scanning direction in the X direction) is very small, the aperture of the lens of the transducer element in this direction is very small, so that the resolution in the Y direction is very small. Summary of the invention

[0008] The object of the invention is to increase the application possibilities in scanning acoustic microscopy, respectively in acoustic microscopy for examining samples, such as wafers etc. Another object of the invention is to examine large-volume, correspondingly large-area samples in an efficient and simple manner, in particular with a high data throughput, by means of an acoustic microscope, in particular an ultrasound scanning microscope.

[0009] The object is solved by a method for operating a scanning acoustic microscope, in particular an ultrasound scanning microscope, wherein a sample is scanned in an XY plane by a transducer unit, in particular with one or more transducer elements, each comprising a transducer and a lens; wherein the transducer unit is moved in an X direction for a linear scan of the sample; wherein, after one or more linear scans of the sample by the transducer unit, the transducer unit is displaced in a Y direction by displacement increments, wherein the size of the displacement increments of the transducer unit in the Y direction is changed for the scanning of the sample; wherein in particular, after the displacement of the transducer unit in the Y direction, at least one further linear scan of the sample is performed by the transducer unit in the Y direction.

[0010] A particular advantage of the method is that during the inspection of a sample by a scanning method, the displacement increment of the transducer unit in the Y direction is changed during the execution of the scanning method, thereby enabling the scanning to inspect a specific area of ​​the sample with a higher (pixel) resolution and other less interesting areas of the sample with a lower (pixel) resolution, respectively. As a result, the time for the entire inspection of the sample can be shortened.

[0011] Another advantage of the method is that the scanning method allows the use of a plurality of transducer units with a plurality of transducer elements, wherein the lateral dimensions of these transducer elements are greater than the pixel size, wherein restrictions on the free choice of the pixel size and losses in the resolution capability and detection sensitivity are avoided in the method according to the invention. Specifically, for example, the deviations of the individual transducer elements from a reference position are calibrated and entered into a calibration table. The surface to be scanned of the sample is divided in a transducer unit with transducer elements of the same focal length, wherein the sample is scanned line by line by each individual transducer element.

[0012] The acoustic microscope (particularly an ultrasonic scanning microscope) for implementing the method comprises a positioning system, at least one transducer unit (particularly, having a number of transducer elements), a pulse generator unit for the transducer unit, (preferably, having a number of pulse generators corresponding to the number of transducer elements), and a receiving unit (particularly, one receiving device for each transducer element). In addition, the acoustic microscope comprises a data processing system and a module for digitizing the received analog ultrasonic signal.

[0013] In the method according to the invention, it is preferred that, in the case of a transducer unit with several transducer elements, the lateral distances of these individual transducer elements are taken into account based on a (pre)calibration, so that the surface of the sample to be inspected and scanned will be scanned in an optimized manner. Thus, in the case of a continuous line-by-line (i.e. linear) scanning (in the X direction) with a predetermined and configurable number of image points per line, the distance from line to line in the Y direction can be freely selected. Preferably, the linear scanning is performed in the Y direction with the same small displacement increments until the maximum distance between transducer elements of the same characteristics is reached, and then the transducer unit is moved in the Y direction by this distance with large displacement increments in the Y direction, so that a high-resolution image of the surface to be inspected is generated with an increased analysis speed.

[0014] In a further development of the method, it is provided that a number of linear scans of the sample (in the X direction) are performed by the transducer unit, wherein after the linear scan of the sample the transducer unit is in each case displaced in the Y direction by a small displacement increment, which is preferably constant in each case; and after a number of linear scans of the sample a predetermined number n (n≥2, 3, ...) of times the transducer unit is displaced in the Y direction by a large displacement increment, which is preferably constant and is greater than the small displacement increment, And / or, after the linear scanning of the sample, the transducer unit is displaced in the Y direction with a large displacement increment, and the large displacement increment is preferably constant; and, after the transducer unit is displaced with the large displacement increment, several n (n≥2, 3, ...) linear scans of the sample are performed by the transducer unit, wherein, after each linear scan of the several n (n≥2, 3, ...) linear scans of the sample, in each case the transducer unit is displaced in the Y direction with a small displacement increment, and the small displacement increment is preferably constant, and the small displacement increment is smaller than the large displacement increment.

[0015] Thus, a high-resolution image of the surface to be inspected of the sample is obtained, wherein, for example, the distance of each linear scan of the pixel size (in the Y direction) is smaller than the distance of individual transducer elements (in the Y direction) of the (preferably linear) transducer element array. Specifically, the ratio of the distance of each linear scan of the pixel size to the distance of individual transducer elements (in the Y direction) is smaller than 1:10, specifically smaller than 1:100, further specifically 1:1000.

[0016] Furthermore, preferably, in the method, when the transducer unit is moved in a tortuous path in the XY plane relative to the sample. For this purpose, a corresponding positioning system is provided in order to move the transducer unit relative to the sample to be examined.

[0017] According to another exemplary embodiment, in the method it is provided that:

[0018] a.) scanning the sample by using a transducer unit for a scanning acoustic microscope, in particular an ultrasound scanning microscope, the transducer unit having a number of transducer elements each comprising a transducer and a lens, wherein at least two transducer elements comprise different focal lengths, or

[0019] b.) scanning the sample by using a transducer unit having several transducer elements each comprising a transducer and a (preferably acoustic) lens, wherein in particular the transducer elements comprise the same focal length and / or the transducer elements are arranged adjacent to each other in a linear or diamond arrangement in the Y direction.

[0020] Furthermore, a further development of the method is distinguished in that the transducer unit comprises a number of transducer elements arranged in the Y direction, preferably the number of transducer elements are arranged one behind the other and / or linearly, wherein a number of m (m≥2, 3, 4, ...) linear scans are performed in the X direction by the corresponding transducer elements, wherein the distances of the m (m≥2, 3, 4, ...) linear scans performed by the corresponding transducer elements are equidistant in the Y direction, and after performing m (m≥2, 3, 4, ...) linear scans by the transducer unit, the transducer unit is displaced in the Y direction by a displacement increment corresponding to the product of the equidistant distance of the linear scans and the number of m (m≥2, 3, 4, ...) linear scans and the number of transducer elements of the transducer unit in the Y direction.

[0021] Advantageously, in the method, for example, the image resolution to be obtained is independent of the distance and arrangement of the individual transducer elements (eg of the array). Furthermore, these individual transducer elements are freely adjustable and individually optimizable with respect to their resolving power and their signal strength.

[0022] The image resolution obtained or to be obtained by the method is independent of the distance and arrangement of the individual transducer elements of the transducer unit or transducer array, wherein in particular the individual transducer elements can be configured as required with regard to their resolving power and their focal length.

[0023] Due to the use of transducer elements of different focal lengths in the transducer unit, according to the method in one embodiment, the surface or plane to be inspected of the sample is scanned in one or more depth planes, each depth plane being or to be determined by the respective focal length of the individual transducer elements of the transducer unit of the transducer array. Furthermore, according to another aspect, it is provided that the lateral deviation of each individual transducer element is calibrated and the scanning field is magnified by a corresponding amount, wherein possible deviations are corrected during the generation of gap-free and consistent images.

[0024] In a further exemplary embodiment, in the method, it is provided that the transducer unit (preferably having several transducer elements) comprises a length in the Y direction, wherein, after the transducer unit performs several linear scans in the X direction, the transducer unit is displaced in the Y direction with a displacement increment corresponding to the length of the transducer unit, wherein the respective distances of the several linear scans performed with the displacement increment corresponding to the length of the transducer unit before the transducer unit is displaced in the Y direction correspond to a natural fraction of the length of the transducer unit (length of the transducer unit / t, t≥2, 3, 4, ...).

[0025] Further, in a method according to a further development, it is provided that the transducer unit comprises several transducer elements arranged in the Y direction, preferably, the several transducer elements are arranged adjacent to each other and / or linearly, wherein the transducer elements each comprise a width in the Y direction, which width is preferably constant, wherein a number of p (p ≥ 2, 3, 4, ...) linear scans are performed in the X direction, wherein the distance between the p (p ≥ 2, 3, 4, ...) linear scans corresponds to a fraction of the width of the transducer element (width of the transducer element / p, p ≥ 2, 3, 4, ...), and after performing the p (p ≥ 2, 3, 4, ...) linear scans, the transducer unit is displaced in the Y direction by a displacement increment, which corresponds to a multiple of the width of the transducer element.

[0026] In one configuration of the method, preferably, after performing several linear scans by the transducer unit, the displacement increment of the transducer unit in the Y direction is corrected by a tolerance correction value, and the displacement increment is specifically a large displacement increment, wherein specifically, the tolerance correction value is formed so that the distance in the Y direction from the last linear scan before the transducer unit is displaced by the large displacement increment to the first linear scan after the transducer unit is displaced by the large displacement increment corresponds to the distance in the Y direction of several linear scans before and / or after the transducer unit is displaced by the large displacement increment, or wherein, specifically, the tolerance correction value is formed so that the distance between all linear scans of the transducer unit is constant.

[0027] In particular, the transducer unit comprises several transducer elements, wherein the transducer elements are operated in parallel. Preferably, the pulse generator for each transducer element and / or the receiving device for each transducer element are operated in parallel. Alternatively, in one configuration, the pulse operation is performed with a time offset of the total decay time of the transducer signal, wherein crosstalk of individual transducer elements is minimized and / or the signal of a transducer element caused by the acoustic wave does not interfere with adjacent transducer elements.

[0028] In the context of the invention, it is possible that, for carrying out the method, the transducer unit is provided with several transducer elements in a compact design, wherein the transducer elements are separated from one another, or with a monolithic block for the transducer elements.

[0029] Furthermore, in the method, in one configuration, it is provided that the distance between the transducer unit and the surface of the sample is controlled by the transducer elements. Alternatively, the distance control between the transducer unit and the sample can be achieved by weighting values ​​of various transducer elements (e.g., by using a corresponding algorithm).

[0030] To carry out the method, a transducer unit for a scanning acoustic microscope, in particular an ultrasound scanning microscope, is provided, the transducer unit having several transducer elements each comprising a transducer and a (preferably acoustic) lens, wherein at least two transducer elements comprise different focal lengths.

[0031] In the case of a transducer unit used in a scanning acoustic microscope, several linear scans are performed simultaneously in a (preferably single) scanning method, wherein, due to the different focal lengths of the transducer elements of the transducer unit, these scans are performed simultaneously in different planes of the sample. Thus, during the scanning operation, different scan fields of the sample to be examined are obtained in different planes of the sample.

[0032] In addition to the transducer for generating the sound signal and the acoustic lens for focusing, the individual transducer elements still include a pulse generator, a transmit / receive switch, a receiver for receiving the sound signal reflected or emitted by the sample, and an A / D converter for converting the received sound signal into a digital value for displaying a (grayscale) image. The ultrasonic signal reflected or emitted by the sample is measured and converted for generating an image. In addition, the propagation time of the signals or their phase shift can be obtained as further image information. In the scanning method, the sample is scanned pixel by pixel and line by line. Thereby, the converter unit or converter element is moved relative to the sample being inspected.

[0033] For this purpose, in a preferred further development of the transducer unit, it is provided that, preferably exclusively, two transducer elements having different focal lengths relative to the XY plane are arranged adjacent to each other in a linear arrangement in the Y direction or one behind each other in the X direction, or, preferably exclusively, two transducer elements having different focal lengths relative to the XY plane are arranged (in particular diagonally) displaced towards each other in the X direction and in the Y direction.

[0034] Furthermore, a further configuration of the transducer unit is distinguished in that the transducer unit comprises a number of transducer elements each having a first focal length and a number of transducer elements each having a second focal length, the second focal length being different from the first focal length relative to the XY plane,

[0035] wherein the transducer element arrays having a first focal length in the Y direction and arranged adjacent to each other (specifically linearly) and the transducer element arrays having a second focal length in the Y direction and arranged adjacent to each other (specifically linearly) are arranged one behind the other in the X direction,

[0036] or wherein an array of transducer elements arranged adjacent to each other (in particular linearly) having a first focal length in the Y direction and an array of transducer elements (1, 2, 3, 4, 12, 14) arranged adjacent to each other (in particular linearly) having a second focal length in the Y direction are arranged (in particular diagonally) displaced towards each other in the X direction and in the Y direction,

[0037] Or wherein the transducer elements having the first focal length and the transducer elements having the second focal length are arranged one behind the other in an alternating sequence (particularly diagonally) in the Y direction.

[0038] According to an advantageous further development, the transducer unit comprises in particular more than two transducer elements, each with a first focal length, and in particular more than two transducer elements, each with a second focal length. Due to the (in particular parallel or simultaneous) use of several arrays with several transducer elements for acoustic microscopy, in particular transducer elements with two or more first focal lengths and transducer elements with two or more second focal lengths, the application possibilities of acoustic microscopy are increased, since during the examination of the sample several, respectively exposed images are obtained simultaneously in each case in different planes by transducer elements with different focal lengths. Furthermore, due to the array, the time for the examination in a scanning method is shortened, since several transducer elements of one focal length scan the sample in the Y direction over a larger width or a wider scanning field.

[0039] Further, the object is solved by a scanning acoustic microscope, in particular an ultrasound scanning microscope, wherein the scanning acoustic microscope is formed by a transducer unit as described above or the scanning acoustic microscope is configured to perform a method for operating an acoustic microscope according to any of claims 1 to 11. In order to avoid repetitions, reference is explicitly made to the above explanations.

[0040] Incidentally, in the context of the present invention, a method for operating a scanning acoustic microscope (specifically an ultrasonic scanning microscope) is provided as a separate object of the present invention, wherein a sample is scanned in an XY plane by means of the above-mentioned transducer unit, specifically using one or more transducer elements each comprising a transducer and a lens; wherein the transducer unit moves in the X direction for linear scanning of the sample; wherein, after one or more linear scans of the sample are performed by the transducer unit, the transducer unit is displaced in the Y direction by a displacement increment, wherein the size of the displacement increment of the transducer unit in the Y direction is changed for the scanning of the sample; wherein specifically, after the transducer unit is displaced in the Y direction, at least one further linear scan of the sample is performed by the transducer unit in the Y direction.

[0041] In this case, it is provided that, in the above-mentioned scanning method, after each linear scan in the X direction, the sample to be examined is displaced in the Y direction by means of a transducer unit with a constant displacement increment. Preferably, the transducer unit comprises several transducer elements, which operate in parallel. In particular, according to another aspect, the transducer unit is moved in a zigzag path relative to the sample in the XY plane.

[0042] Further features of the present invention will become clear from the description of the embodiments according to the present invention and the claims and drawings. According to the embodiments of the present invention, individual features or a combination of several features can be realized.

[0043] In the context of the present invention, features identified with "specifically" or "preferably" are to be understood as optional features. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The invention will be described below based on a number of exemplary embodiments and with reference to the accompanying drawings without limiting the general inventive concept, and with regard to any details according to the invention that are not further described in the text, explicit reference is made to the accompanying drawings. They are shown below:

[0045] Figure 1a and Figure 1b schematically shows a perspective cross-sectional view of a transducer unit for an acoustic microscope in each case;

[0046] Figure 2a , Figure 2b schematically show in each case a perspective cross-sectional view of a further transducer unit for an acoustic microscope;

[0047] Figure 3 A single scanning field of a transducer unit of an acoustic microscope for examining a sample is schematically shown;

[0048] Figure 4Schematically shows the entire scanning field of a transducer unit of an acoustic microscope for examining a sample;

[0049] Figure 5 A schematic diagram showing in detail the tortuous scanning path of the transducer unit on the sample surface, and

[0050] Figure 6 The scanning field of another transducer unit is schematically shown.

[0051] In the drawings, elements and / or parts of the same or similar types are provided with the same reference numerals, thereby omitting the corresponding re-introduction, respectively. DETAILED DESCRIPTION

[0052] Figure 1a and Figure 1b Schematic perspective views of a cross section of a transducer unit 10 for an acoustic microscope, in particular an ultrasound scanning microscope, are respectively shown.

[0053] Figure 1a The transducer unit 10 in the embodiment includes transducer elements 1, 2, 3, 4 in the Y direction (i.e., perpendicular to the scanning direction of the transducer unit 10 in the X direction), which are arranged in a linear arrangement adjacent to each other, and all of these transducer elements 1, 2, 3, 4 include the same focal length. The transducer elements 1, 2, 3, 4 are identical in construction and each includes a transducer 20 and an acoustic lens 21, which is arranged on the transducer 20 for focusing the ultrasound signal onto the sample to be detected.

[0054] exist Figure 1b In the exemplary embodiment of the invention, the transducer unit 10 comprises transducer elements 1, 12, 3 and 14 which are arranged linearly in an alternating order in the Y direction. The transducer elements 1 and 3 each have a (first) focal length, and the transducer elements 12 and 14 have a (second) focal length, which is different from the focal length of the transducer elements 1 and 3 and the focal length of the transducer elements 12 and 14. The transducer elements 12 and 14 here have a lens 22, which has a focal length different from the focal length of the lens 21 for the transducer elements 1 and 3.

[0055] exist Figure 2a and Figure 2b Schematic perspective views of cross sections of transducer units 10 for acoustic microscopes (particularly ultrasonic scanning microscopes) are shown in FIG.

[0056] according to Figure 2a and Figure 2b Another design of the transducer unit 10 is based on Figure 1a and Figure 1b The configurations of the transducer units 10 differ in the arrangement of the transducer elements.

[0057] In accordance with Figure 2a The configuration of the transducer unit 10 is Figure 1a Compared to the transducer unit 10 in FIG. 1 , the transducer elements 1 and 3 are displaced in the X direction relative to the transducer elements 2 and 4. The transducer elements 1 , 2, 3 and 4 each comprise the same focal length.

[0058] In accordance with Figure 2b The configuration of the transducer unit 10 is Figure 1b Compared to the transducer unit 10 in FIG. 1 , the transducer elements 1 and 3 are displaced in the X direction relative to the transducer elements 12 and 14. The transducer elements 1 and 3 comprise the same focal length which is different from the focal length of the transducer elements 12 and 14, respectively.

[0059] exist Figure 3 The schematic diagram shows the Figure 1a A single first scanning field 100.1 of a transducer unit 10 of a configuration, wherein the transducer elements 1, 2, 3, 4 comprise the same focal length for the sample to be examined. For example, by means of the transducer elements 1, 2, 3, 4 in the Y position Y1, image line Y1 transducer element 1, image line Y1 transducer element 2, image line Y1 transducer element 3, image line Y1 transducer element 4 are simultaneously obtained in a linear scan of the sample as a display (e.g. on a monitor) corresponding to the reflection signals of the transducer elements 1, 2, 3, 4 received from the sample in the scan in the X direction.

[0060] Next, in the end position, the transducer unit 10 is moved in the Y direction by a small displacement increment U from the Y position Y1 to the Y position Y2 (see Figure 5 ), so that in a linear scan of the sample, image line Y2 transducer element 1, image line Y2 transducer element 2, image line Y2 transducer element 3, image line Y2 transducer element 4 are obtained from the sample. Then, the transducer unit 10 is moved from the Y position Y2 to the Y position Y3 by a small displacement increment U (see Figure 5 ), wherein the image line Y3 transducer element 1, image line Y3 transducer element 2, image line Y3 transducer element 3, image line Y3 transducer element 4 are then obtained by transducer elements 1, 2, 3, 4. In a similar manner, the transducer unit 10 is further moved from the Y position Y3 to the Y position Y4 in the Y direction by a small displacement increment U (see Figure 5 ) so that in the subsequent linear scan in the X direction, image line Y4 transducer element 1, image line Y4 transducer element 2, image line Y4 transducer element 3, and image line Y4 transducer element 4 are simultaneously obtained.

[0061] exist Figure 4, the entire scanning field 100 of the transducer unit 10 of the acoustic microscope for sample inspection is schematically shown. After acquiring the entire scanning field 100.1 with four linear scans in the X direction, as shown in FIG. Figure 3 As shown in the figure, the transducer unit 10 is displaced in the Y direction with a displacement increment W, which is greater than the displacement increment U between the Y positions Y1, Y2, Y3, and Y4 (see Figure 5 ). Specifically, the displacement increment W of the transducer unit 10 in the Y direction corresponds to the length generated by the product of the equidistant distance U of the linear scan and the number of m (in the current case, m=4) linear scans and the number of transducer elements of the transducer unit 10 in the Y direction (in the current exemplary case: four).

[0062] In another configuration, the Y distance of the four linear scans in positions Y1, Y2, Y3 and Y4 corresponds to a small fraction of the width of transducer elements 1, 2, 3, 4, wherein after performing four linear scans in the X direction, the transducer unit is displaced in the Y direction by a displacement increment corresponding to a multiple of the transducer element width.

[0063] After acquiring and completing the display scan field 100.1, as Figure 3 As shown, and after moving a large displacement increment W in the Y direction (see Figure 5 ), the transducer unit 10 is moved from the Y position Y4 to the Y position Y5 to acquire the subsequent scanning field 100.2, wherein, in the scanning method for acquiring the scanning field 100.2, the transducer unit 10 is subsequently moved in a zigzag manner from the Y position Y5 to the further Y positions Y6, Y7 and Y8, so that by means of a linear scan of the sample corresponding image lines are generated for the four Y positions Y5, Y6, Y7 and Y8 by means of the transducer elements 1, 2, 3, 4. These method steps are repeated several times in a corresponding manner between the individual Y positions of the transducer unit 10 and between two consecutive scanning fields until the last scanning field 100.n of the Y positions Yn, Yn+1, Yn+2, Yn+3 has been scanned by the transducer elements 1, 2, 3, 4 and corresponding image lines have been generated.

[0064] In the context of the present invention, it is possible to use Figure 1b or Figure 2a or Figure 2b A transducer unit 10 of the schematic configuration or another transducer unit having a plurality of transducer elements is used to replace the transducer unit 10 of the schematic configuration Figure 1a A transducer unit 10 is arranged in a predetermined arrangement in the X direction and / or in the Y direction and / or comprises different focal lengths for acquiring the entire scanning field 100, wherein during the scanning method the transducer unit 10 is moved according to a scanning method with different displacement increments in the Y direction, in particular a zigzag scanning method.

[0065] Figure 5 A schematic diagram showing in detail the scanning route of the transducer unit 10 (see Figure 4 ), the transducer unit 10 having four transducer elements 1, 2, 3, 4 across a portion of the sample surface of the sample. To acquire the scanning fields 100.1 and 100.2, the transducer unit 10 is moved by a (small) displacement increment U in the Y direction between several Y positions Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8 of the respective scanning fields 100.1 and 100.2, respectively, and after acquiring the scanning fields 100.1 or 100.2, by a displacement increment W greater than the displacement increment U.

[0066] The movement of the transducer unit 10 is performed in the form of a meander 30, whereby the sample is scanned in a meandering manner. Thus, in order to acquire the entire scanning field 100, the Y increments of the meander 30 of the transducer unit 10 vary with the displacement increments U and W in the Y direction.

[0067] exist Figure 6 In an exemplary embodiment of , a transducer unit 10 is schematically shown with two transducer elements 1 and 12 and overall scanning fields 101 and 112 for the two transducer elements 1 and 12. In this configuration, the transducer elements 1 and 12 comprise different focal lengths.

[0068] As from Figure 6 As can be seen in FIG. 1 , the transducer elements 1 and 12 are arranged to be displaced diagonally in the X direction and in the Y direction on the transducer unit 10, so that when scanning the sample, the entire scanning field 101 for the transducer element 1 and the entire scanning field 112 for the transducer element 12 are also formed with an offset in the X direction and in the Y direction respectively. Therefore, the generated entire scan image 101, 102 obtained with the transducer elements 1 and 12 is displayed with an offset. In one configuration, the transducer unit 10 is moved across the sample in a zigzag manner so as to perform a linear scan through the transducer elements 1 and 12, wherein the Y increment is constant between two linear scans.

[0069] In another configuration (not shown here), instead of Figure 6 The transducer unit 10 shown in FIG. 1 , for example, Figure 2bThe transducer unit 10 represented in FIG. 1 is used for acquiring the entire scanning field 101 and 112, wherein the transducer unit 10 is moved in each case according to a scanning method with different displacement increments in the Y direction, in particular a zigzag method. Furthermore, other configurations of the scanning method are also possible by using a transducer unit with several transducer elements, which have different focal lengths, wherein the transducer unit is moved according to a scanning method with different displacement increments in the Y direction, in particular a zigzag method, during the acquisition of the entire scanning field.

[0070] All cited features, including also those features taken from the drawings alone, and individual features disclosed in combination with other features, are considered essential to the invention both individually and in combination. Embodiments according to the invention can be realized by individual features or a combination of several features.

[0071] Reference numerals list

[0072] 1, 2, 3, 4 transducer elements

[0073] 10 transducer units

[0074] 12, 14 Transducer elements

[0075] 20 transducers

[0076] 21, 22 lenses

[0077] 30 twists and turns

[0078] 100 Entire scan domain

[0079] 101 The entire scan domain

[0080] 100.1, 100.2, ..., 100.n scanning domain

[0081] 112 The entire scan area

[0082] U displacement increment

[0083] W displacement increment

Claims

1. A method for operating a scanning acoustic microscope, wherein the scanning acoustic microscope is particularly an ultrasonic scanning microscope; wherein: A sample is scanned in an XY plane by a transducer unit (10), specifically using one or more transducer elements (1, 2, 3, 4, 12, 14) each comprising a transducer and a lens; wherein the transducer unit (10) is moved in the X direction for linear scanning of the sample; wherein, after one or the linear scanning of the sample by the transducer unit (10), the transducer unit (10) is displaced in the Y direction by a displacement increment, wherein the size of the displacement increment of the transducer unit (10) in the Y direction is changed for the scanning of the sample; wherein, specifically, after the displacement of the transducer unit (10) in the Y direction, at least one further linear scan of the sample is performed by the transducer unit (10) in the Y direction.

2. The method according to claim 1, characterized in that performing several linear scans of the sample by means of the transducer unit (10), wherein after the linear scan of the sample the transducer unit (10) is in each case displaced in the Y direction by a small displacement increment (U), which is preferably constant in each case; and After performing a predetermined number n (n≥2, 3, ...) of linear scans on the sample, the transducer unit (10) is displaced in the Y direction by a large displacement increment (W), the large displacement increment (W) is preferably constant, the large displacement increment (W) is greater than the small displacement increment (U), and / or, after performing a linear scan on the sample, the transducer unit (10) is displaced in the Y direction by a large displacement increment (W), the large displacement increment (W) is preferably constant; and, After the transducer unit (10) is displaced by a large displacement increment (W), the sample is subjected to several n (n≥2, 3, ...) linear scans by the transducer unit (10), wherein after each of the several n (n≥2, 3, ...) linear scans of the sample, the transducer unit (10) is displaced in the Y direction by a small displacement increment (U) in each case, the small displacement increment (U) being preferably constant and smaller than the large displacement increment (W).

3. The method according to claim 1 or 2, characterized in that: The transducer unit (10) moves in a tortuous path relative to the sample in the XY plane.

4. The method according to any one of claims 1 to 3, characterized in that a.) scanning the sample by using a transducer unit (10) with a plurality of transducer elements (1, 2, 3, 4, 12, 14) each comprising a transducer (20) and a lens (21, 22), the transducer unit (10) being used for a scanning acoustic microscope, in particular an ultrasonic scanning microscope, wherein at least two transducer elements (1, 2, 3, 4, 12, 14) comprise different focal lengths, or b.) scanning the sample by using a transducer unit (10) with a plurality of transducer elements (1, 2, 3, 4, 12, 14) each comprising a transducer (20) and a lens (21, 22), wherein the lenses (21, 22) are preferably acoustic lenses, wherein, in particular, the transducer elements (1, 2, 3, 4, 12, 14) comprise the same focal length, and / or the transducer elements (1, 2, 3, 4, 12, 14) are arranged adjacent to each other in a linear or diamond arrangement in the Y direction.

5. The method according to any one of claims 1 to 4, characterized in that The transducer unit (10) comprises a plurality of transducer elements (1, 2, 3, 4, 12, 14) arranged in the Y direction, preferably, the plurality of transducer elements (1, 2, 3, 4, 12, 14) are arranged back and forth and / or linearly in the Y direction, wherein a plurality of m (m≥2, 3, 4, ...) linear scans are performed in the X direction by corresponding transducer elements (1, 2, 3, 4, 12, 14), wherein the m (m≥2, 3, 4, 12, 14) linear scans are performed by corresponding transducer elements (1, 2, 3, 4, 12, 14) 2, 3, 4, ...) times of linear scanning are equidistant in the Y direction, and, after performing m (m≥2, 3, 4, ...) times of linear scanning by the transducer unit (10), the transducer unit (10) is displaced in the Y direction by the displacement increment, and the displacement increment corresponds to the product of the equidistant distance of the linear scanning and the number of m (m≥2, 3, 4, ...) times of linear scanning and the number of the transducer elements (1, 2, 3, 4, 12, 14) of the transducer unit (10) in the Y direction.

6. The method according to any one of claims 1 to 5, characterized in that The transducer unit (10) preferably has a plurality of transducer elements (1, 2, 3, 4, 12, 14), and the transducer unit (10) includes a length in the Y direction; wherein, after the transducer unit (10) performs a plurality of linear scans in the X direction, the transducer unit (10) is displaced in the Y direction with a displacement increment corresponding to the length of the transducer unit (10); wherein, before the transducer unit (10) is displaced in the Y direction, each distance of the plurality of linear scans performed with a displacement increment corresponding to the length of the transducer unit (10) corresponds to a natural fraction of the length of the transducer unit (10) (the length of the transducer unit (10) / t, t≥2, 3, 4, ...).

7. The method according to any one of claims 1 to 5, characterized in that The transducer unit (10) comprises a plurality of transducer elements (1, 2, 3, 4, 12, 14) arranged in the Y direction, preferably, the plurality of transducer elements (1, 2, 3, 4, 12, 14) are arranged adjacent to each other and / or linearly in the Y direction; wherein the transducer elements (1, 2, 3, 4, 12, 14) each comprise a width in the Y direction, and the width is preferably constant; wherein a plurality of p (p ≥ 2, 3, 4, ...) linear scans are performed in the X direction, wherein p ( The distance between p (p ≥ 2, 3, 4, ...) sub-linear scans corresponds to a fraction of the width of the transducer element (1, 2, 3, 4, 12, 14) (the width of the transducer element (1, 2, 3, 4, 12, 14) / p, p ≥ 2, 3, 4, ...), and after performing p (p ≥ 2, 3, 4, ...) sub-linear scans, the transducer unit (10) is displaced in the Y direction by the displacement increment, and the displacement increment corresponds to a multiple of the width of the transducer element (1, 2, 3, 4, 12, 14).

8. The method according to any one of claims 5 to 7, characterized in that Specifically, after performing several linear scans by the transducer unit (10), the displacement increment (W) of the transducer unit (10) in the Y direction is corrected by a tolerance correction value, and the displacement increment is specifically a large displacement increment, wherein, specifically, the tolerance correction value is formed so that the distance in the Y direction from the last linear scan of the transducer unit (10) before being displaced by the large displacement increment (W) to the first linear scan after the transducer unit is displaced by the large displacement increment (W) corresponds to the distance in the Y direction of several linear scans before and / or after the transducer unit (10) is displaced by the large displacement increment (W), or wherein, specifically, the tolerance correction value is formed so that the distance between all linear scans of the transducer unit (10) is constant.

9. The method according to any one of claims 1 to 8, characterized in that The transducer unit (10) comprises a plurality of transducer elements (1, 2, 3, 4, 12, 14), wherein the transducer elements (1, 2, 3, 4, 12, 14) operate in parallel.

10. The method according to any one of claims 4 to 9, characterized in that In particular, in case a.), preferably exclusively, two transducer elements (1, 2, 3, 4, 12, 14) having different focal lengths relative to the XY plane are adjacent to each other in a linear arrangement in the Y direction or are arranged one behind the other in the X direction, or, preferably exclusively, two transducer elements (1, 2, 3, 4, 12, 14) having different focal lengths relative to the XY plane are arranged displaced toward each other in the X direction and in the Y direction, particularly diagonally.

11. The method according to any one of claims 4 to 10, characterized in that Specifically in case a.), the transducer unit (10) comprises a plurality of transducer elements (1, 2, 3, 4, 12, 14) each having a first focal length and a plurality of transducer elements (1, 2, 3, 4, 12, 14) each having a second focal length, the second focal length being different from the first focal length relative to the XY plane, wherein an array of transducer elements (1, 2, 3, 4, 12, 14) having the first focal length in the Y direction and being linearly arranged adjacent to each other and an array of transducer elements (1, 2, 3, 4, 12, 14) having the second focal length in the Y direction and being linearly arranged adjacent to each other are arranged one behind the other in the X direction, or wherein an array of transducer elements (1, 2, 3, 4, 12, 14) having the first focal length in the Y direction, in particular arranged linearly adjacent to one another, and an array of transducer elements (1, 2, 3, 4, 12, 14) having the second focal length in the Y direction, in particular arranged linearly adjacent to one another, are arranged displaced toward one another in the X direction and in the Y direction, in particular arranged diagonally, Or wherein a plurality of transducer elements (1, 2, 3, 4, 12, 14) having the first focal length and a plurality of transducer elements (1, 2, 3, 4, 12, 14) having the second focal length are arranged in an alternating order in front and behind in the Y direction, specifically in a linear arrangement.

12. A scanning acoustic microscope, in particular an ultrasonic scanning microscope, wherein: The scanning acoustic microscope is configured to perform the method according to any one of claims 1 to 11.

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