Defect detection method and system

Abstract

The invention provides a defect detection method and a defect detection system. According to the detection method, on the basis of learning that echo information of ultrasonic waves on film layers made of different materials is different, whether defects exist in a preset area or not can be judged according to whether the echo information of the film layers in the preset area is matched with standard information of the corresponding film layers or not. The detection method can be applied to defect judgment of all the film layers and can also be used for defect judgment of the contact holes, the convenient and efficient detection effect is achieved, and the product yield is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a defect detection method and a defect detection system. Background Art

[0002] With the advancement of semiconductor manufacturing technology, defect detection has become an indispensable means of improving semiconductor yield. During the production of large integrated circuits, it is necessary to promptly check for defects on the substrate at different process nodes to promptly explore the mechanism of defect generation, thereby enabling targeted optimization and improving product yield.

[0003] Specifically, the semiconductor manufacturing process typically includes thin film deposition, photolithography, and etching processes, which form the desired film layer on the substrate and perform patterning on the film layer. However, in actual manufacturing, problems such as process drift can easily lead to abnormalities in the deposited film layer or patterning, which in turn increases the risk of device failure. Therefore, it is necessary to provide a convenient and efficient defect detection method. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a defect detection method to conveniently and efficiently detect whether there are defects on a substrate and improve product yield.

[0005] To this end, the present invention provides a defect detection method, comprising: providing a substrate on which at least two film layers of different materials are stacked in sequence; scanning the substrate with ultrasound and collecting feedback information, wherein the feedback information at least includes echo information from the film layer in a predetermined area; and comparing the echo information of the film layer in the predetermined area with standard information of the corresponding film layer to determine whether there is a defect in the predetermined area.

[0006] Optionally, a contact hole is formed in the predetermined area, and the contact hole extends from the top film layer toward the target film layer below; wherein the feedback information includes echo information from the film layer at the bottom of the contact hole, and the echo information from the contact hole is compared with the standard information corresponding to the film layer at the bottom of the standard contact hole to determine whether the contact hole has defects.

[0007] Optionally, the detection method further includes: inferring the specific film layer where the bottom of the contact hole is located based on echo information from each film layer in the contact hole.

[0008] Optionally, the standard information corresponding to the standard contact hole includes standard information corresponding to the target film layer, but does not include standard information for other film layers located on the sides of the standard contact hole and above the target film layer. The method for detecting the contact hole includes: determining whether the echo information from the contact hole matches the standard information of the standard contact hole; if so, the contact hole is normal; if not, the contact hole is abnormal, and further analyzing the echo information of each film layer included in the echo information of the contact hole to infer the specific film layer where the bottom of the contact hole is located.

[0009] Optionally, the contact hole is further filled with a metal layer; wherein the echo information from the contact hole includes: echo information of the film layer at the bottom of the contact hole and echo information of the metal layer.

[0010] Optionally, at least two film layers made of different materials are stacked in sequence in the predetermined area; the feedback information includes echo information from each film layer in the predetermined area, and the echo information of each film layer is compared one by one with the standard information of the corresponding film layer to determine whether there is a film layer defect in the predetermined area, and / or the film layer where the defect is located, and / or the height position of the defect in the film layer where the defect is located.

[0011] Optionally, the substrate has a first region and a second region, wherein a contact hole is formed in the first region and no contact hole is formed in the second region. The feedback information includes: echo information from a film layer at a bottom of the contact hole in the first region; and echo information from each film layer in the second region.

[0012] Optionally, the method for acquiring standard information of each film layer includes: performing ultrasonic scanning on a standard substrate that meets expectations to obtain echo information of each film layer on the standard substrate, which is used to constitute the standard information of each film layer.

[0013] Optionally, the standard substrate has a first region and a second region, wherein a standard contact hole is formed in the first region and no contact hole is formed in the second region, wherein the standard contact hole extends downward from the top film layer and stops at the target film layer. The echo information from the first region includes standard information corresponding to the target film layer, but does not include standard information for other film layers above the target film layer and to the sides of the standard contact hole; and the echo information from the second region includes standard information for each film layer.

[0014] Optionally, the method of ultrasonically scanning the substrate includes: filling a liquid film between an ultrasonic transmitting end and a surface of the substrate, so that the ultrasonic wave scans the substrate via the liquid film.

[0015] Optionally, the standard information of the film layer includes the standard echo time and the standard signal intensity collected within the standard echo time, and the standard echo time and standard signal intensity corresponding to film layers of different materials are different; wherein, the echo information of the film layer to be detected is compared with the standard information of the corresponding film layer, including: judging whether the echo time and signal intensity from the film layer to be detected match the standard echo time and standard signal intensity of the corresponding film layer.

[0016] Another object of the present invention is to provide a defect detection system, comprising: an ultrasonic detection device for scanning a substrate and collecting feedback information, wherein at least two film layers of different materials are stacked in sequence on the substrate, and the feedback information at least includes echo information from the film layer within a predetermined area; and a data processing unit for comparing the echo information of the film layer within the predetermined area with the standard information of the corresponding film layer one by one to determine whether there is a defect in the film layer within the predetermined area, and / or the film layer where the defect is located, and / or the height position of the defect in the film layer where the defect is located.

[0017] Optionally, a contact hole is formed in the predetermined area, the contact hole extending from the top film layer toward the target film layer below. The ultrasonic detection equipment is configured to collect echo information from the film layer at the bottom of the contact hole; and the data processing unit is configured to compare the echo information from the contact hole with standard information corresponding to the film layer at the bottom of a standard contact hole to determine whether the contact hole is abnormal.

[0018] Optionally, the data processing unit is further configured to infer a specific film layer where the bottom of the contact hole is located based on the echo information from the contact hole.

[0019] Optionally, at least two film layers made of different materials are sequentially stacked within the predetermined area. The ultrasonic detection device is configured to collect echo information from each film layer within the predetermined area; and the data processing unit is configured to compare the echo information of each film layer with standard information of the corresponding film layer to determine whether there are film defects within the predetermined area.

[0020] Optionally, the standard information of the film layer includes a standard echo time and a standard signal intensity collected within the standard echo time. The standard echo time and standard signal intensity corresponding to film layers of different materials are different. The data processing unit is configured to determine whether the echo time and signal intensity from the film layer to be tested match the standard echo time and signal intensity of the corresponding film layer.

[0021] In the defect detection method provided by the present invention, based on the knowledge that ultrasonic echo information differs for film layers of different materials, the presence of a defect in a predetermined area is determined based on whether the echo information of the film layer within the predetermined area matches the standard information of the corresponding film layer. This detection method can be applied to defect detection of individual film layers. For example, the presence of a film defect can be determined based on whether the echo information of the film layer to be detected matches the standard information of the corresponding film layer. Furthermore, this detection method can be applied to defect detection of contact holes. For example, the presence of a defect in the contact hole to be detected can be determined based on whether the echo information of the bottom film layer of the contact hole to be detected matches the standard information of the bottom film layer of a standard contact hole.

[0022] In addition, a further solution of this patent can also realize the simultaneous detection of defects in multiple film layers. Through a single test, it can be determined whether there are defects in multiple film layers, the film layer where each defect is located, and the height position of each defect in the film layer where the defect is located. It can also realize the simultaneous detection of multiple film layer areas and contact hole areas in a single test, which improves the type of detection area and detection efficiency. The defect type in different areas, the film layer where each defect is located, and the height position of each defect in the film layer where the defect is located are determined based on the time information and intensity peak information of the echo. This defect detection method can conveniently and efficiently detect whether there are defects on the substrate, which is conducive to improving product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. 4 is a flow chart of a defect detection method according to an embodiment of the present invention.

[0024] Figure 2 FIG. 4 is a schematic cross-sectional view of a substrate in one embodiment of the present invention.

[0025] Figure 3 FIG. 1 is a schematic diagram of echo information from various film layers on a substrate in one embodiment of the present invention.

[0026] Figure 4 FIG. 1 is a schematic diagram of standard echo information from various film layers on a substrate according to an embodiment of the present invention.

[0027] Figure 5 This is a schematic structural diagram of an ultrasonic detection device in an embodiment of the present invention scanning a substrate.

[0028] Figure 6 and Figure 7 They are respectively regional distribution diagrams of two substrates to be inspected in one embodiment of the present invention.

[0029] The accompanying drawings are numerals as follows:

[0030] 100-substrate;

[0031] 100a-first area;

[0032] 100b-second area;

[0033] 110-first film layer;

[0034] 120- second film layer;

[0035] 130-third film layer;

[0036] 210 / 220-contact hole;

[0037] 310- incentive unit;

[0038] 320-delay unit;

[0039] 330- piezoelectric unit;

[0040] 400-Liquid film. DETAILED DESCRIPTION

[0041] The core idea of ​​the present invention is to provide a defect detection method. Figure 1 As shown, the detection method includes the following steps.

[0042] Step S110 : providing a substrate, on which at least two film layers made of different materials are sequentially stacked.

[0043] Step S120 , scanning the substrate with ultrasound and collecting feedback information, wherein the feedback information at least includes echo information from the film layer in a predetermined area.

[0044] In step S130 , the echo information of the film layer in the predetermined area is compared with the standard information of the corresponding film layer to determine whether there is a defect in the predetermined area.

[0045] Specifically, for films made of different materials, the corresponding echo information will be different. Therefore, it can be determined whether there is a defect in a predetermined area based on the echo information of the film layer in the area.

[0046] For example, a first film layer, a second film layer, and a third film layer made of different materials are sequentially formed within a predetermined region of a substrate. The collected feedback information includes echo information from the first film layer, echo information from the second film layer, and echo information from the third film layer. In this case, due to the different signal strengths of the echo information from the different material layers and the different echo times of the echo information from the film layers at different heights on the substrate, for example, the echo information from the first film layer includes echo information with a first signal strength collected within the first echo time, the echo information from the second film layer includes echo information with a second signal strength collected within the second echo time, and the echo information from the third film layer includes echo information with a third signal strength collected within the third echo time.

[0047] Alternatively, a contact hole is formed in a predetermined area of ​​the substrate, and the contact hole extends from the top film layer toward the target film layer below. At this time, the feedback information collected includes echo information from the film layer at the bottom of the contact hole. On this basis, the echo information from the contact hole can be compared with the standard information corresponding to the standard contact hole to determine whether the contact hole has defects.

[0048] Furthermore, when performing defect inspection on contact holes, the specific film layer where the bottom of the contact hole is located can be inferred based on the echo information from the contact hole. Specifically, the contact hole inspection method includes, for example, determining whether the echo information from the contact hole matches the standard information of a standard contact hole; if so, the contact hole is normal; if not, the contact hole is abnormal. The echo information of each film layer included in the echo information of the contact hole can be further analyzed to infer the specific film layer where the bottom of the contact hole is located. For example, a first film layer, a second film layer, and a third film layer are sequentially formed on a substrate, and the intended contact hole (i.e., the standard contact hole) extends downward from the third film layer to the first film layer. In this case, if the echo information of the contact hole to be inspected includes not only the echo information of the first film layer but also the echo information of the second film layer, it can be inferred that the contact hole is abnormal and its bottom stops in the second film layer and does not reach the target film layer.

[0049] Alternatively, the substrate has a first area and a second area, a contact hole is formed in the first area, and at least two film layers of different materials are stacked in sequence in the second area. In this case, the first area can be inspected for contact hole defects and the second area can be inspected for film layer defects at the same time.

[0050] The defect detection method and detection system proposed in the present invention are described in further detail below in conjunction with specific embodiments. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in illustrating the purpose of the embodiments of the present invention. It should be recognized that relative terms such as "above", "below", "top", "bottom", "above" and "below" shown in the drawings can be used to describe the relationship between various elements. These relative terms are intended to cover different orientations of elements other than the orientations depicted in the drawings. For example, if the device is inverted relative to the view in the drawing, an element described as being "above" another element would now be below that element.

[0051] In step S110, refer to Figure 2 As shown, a substrate 100 is provided, on which at least two film layers made of different materials are stacked in sequence.

[0052] For example Figure 2 In the example, a first film layer 110, a second film layer 120, and a third film layer 130 are sequentially formed on a substrate 100. The materials of the first film layer 110, the second film layer 120, and the third film layer 130 are all different. For example, the first film layer 110 may be a metal layer, such as an aluminum layer or a copper layer; the second film layer 120 may be a nitride layer, such as a silicon nitride layer; and the third film layer 130 may be an oxide layer, such as silicon oxide.

[0053] In this embodiment, the substrate 100 may further be formed with contact holes 210 / 220, which extend from the top film layer toward the target film layer below. That is, the contact holes to be formed sequentially penetrate the film layers above the target film layer and stop at the target film layer. Figure 2 In the example, the substrate 100 has a first region 100a and a second region 100b. A contact hole is formed in the first region 100a. The contact holes 210 / 220 in the first region 100a extend from the third film layer 130 toward the first film layer 110. That is, the first film layer 110 is the target film layer, and the second film layer 120 and the third film layer 130 are the film layers above the target film layer. The contact hole to be formed sequentially penetrates the third film layer 130 and the second film layer 120 and stops on the first film layer 110. That is, Figure 2 The contact hole 210 in the second region 100b satisfies the expected contact hole. In addition, no contact hole is formed in the second region 100b, that is, the first film layer 110, the second film layer 120 and the third film layer 130 therein are not patterned.

[0054] It should be noted that when the preparation process or environmental factors drift, the depth of the contact hole formed may be insufficient and may not reach the target film layer. Figure 2 As shown in the figure, the contact hole 210 penetrates the third film layer 130 and the second film layer 120 to the first film layer 110 (i.e., the target film layer), meeting the depth requirement of the contact hole to be formed as expected; however, the contact hole 220 penetrates the third film layer 130 but does not penetrate the second film layer 120, and thus fails to reach the first film layer 110, thus failing to meet the depth requirement of the contact hole to be formed as expected, and the contact hole 220 has an abnormality.

[0055] In step S120, ultrasonic waves are used to scan substrate 100 and collect feedback information. The collected feedback information includes at least echo information from the film layer within the predetermined area. The vibration frequency of the ultrasonic waves used may be, for example, greater than 20 kHz. Furthermore, the film layer echo information may include, for example, the echo time and the signal strength (t, Q) collected during the echo time.

[0056] The inventors of the present invention have discovered that when ultrasonic waves act on films of different materials, the corresponding echo information obtained will be different, so it is possible to determine whether the scanned film has defects based on the echo information. Figure 2 For example, the feedback information from the second region 100b includes the echo information corresponding to the first film layer 110, the echo information corresponding to the second film layer 120, and the echo information corresponding to the third film layer 130. Figure 3 As shown, the echo information corresponding to the first film layer 110 includes the echo information of the first signal intensity Q1 collected within the first echo time t1, the echo information corresponding to the second film layer 120 includes the echo information of the second signal intensity Q2 collected within the second echo time t2, and the echo information corresponding to the third film layer 130 includes the echo information of the third signal intensity Q3 collected within the third echo time t3.

[0057] In this embodiment, contact holes 210 / 220 are also formed on the substrate 100. Therefore, when ultrasonically scanning the substrate 100, the feedback information collected also includes echo information from the film layer exposed at the bottom of the contact hole. On this basis, the specific film layer reached by the bottom of the contact hole can be further determined to determine whether the contact hole 210 / 220 is abnormal.

[0058] Specifically, when the depth of the contact hole reaches the target film layer, ultrasonic scanning can collect the data from the target film layer (for example Figure 2 The echo information of the first film layer 110 in the contact hole is collected, and since the other film layers above the target film layer at the contact hole position are removed, the other film layers above the target film layer (such as Figure 2However, when the depth of the contact hole does not reach the target film layer, the ultrasonic scanning can not only collect echo information from the target film layer (e.g. Figure 2 The echo information of the first film layer 110 in the target film can also be collected from other film layers above the target film layer (such as Figure 2 For example, Figure 2 In the embodiment, the echo information from the contact hole 210 includes the echo information (t1, Q1) corresponding to the first film layer 110. The echo information from the contact hole 220 includes both the echo information (t1, Q1) corresponding to the first film layer 110 and the echo information of the second film layer 120. In this case, the echo information of the second film layer 120 may deviate from the standard information of the second film layer 120.

[0059] In one example, for example, Figure 5 As shown, the ultrasonic detection device used has multiple ultrasonic transmitters, so that multiple ultrasonic transmitters can be used to scan the substrate 100 at the same time to improve the detection efficiency of the substrate 100. For example, each ultrasonic transmitter can be set on a chip, and multiple chips corresponding to the multiple ultrasonic transmitters can be arranged in an array, and each chip can be independently excited according to a predetermined timing. When multiple chip areas with the same structural design and arranged in an array are formed on the substrate 100, for example Figure 6 The substrate shown in FIG. 1 can now use multiple ultrasonic transmitters in the ultrasonic detection device to perform array scanning on multiple chip areas in the substrate; or, when the structural designs of the multiple chip areas set on the substrate 100 are different, for example Figure 7 The substrate shown can now control the corresponding ultrasonic transmitter to be excited for scanning.

[0060] Continue to refer Figure 5 As shown, the ultrasonic transmitter may include an excitation unit 310 and a piezoelectric unit 330. The excitation unit 310 may be configured to provide a required driving signal (e.g., an AC voltage of a predetermined frequency) and drive the piezoelectric unit 330 based on the driving signal, so that the piezoelectric unit 330 generates an ultrasonic signal corresponding to the driving signal. Optionally, the ultrasonic transmitter may further include a delay unit 320 to synchronize the ultrasonic signals between different ultrasonic transmitters, ensuring that the ultrasonic signals generated by each ultrasonic transmitter are aligned in time.

[0061] In a further solution, the method for ultrasonic scanning also includes: filling a liquid film 400 between the ultrasonic transmitting end and the surface of the substrate 100 (for example, water can be sprayed on the substrate surface to form a water film on the substrate surface), so that the ultrasonic wave will undergo refraction, reflection, and other phenomena when passing through the interface with different acoustic impedances between the liquid film 400 and the substrate 100. At this time, the dielectric materials with different impedances will undergo changes in waveform phase, energy, and other phenomena, thereby obtaining a higher intensity feedback signal.

[0062] In step S130 , the echo information of the film layer in the predetermined area is compared with the standard information of the corresponding film layer to determine whether there is a defect in the predetermined area.

[0063] by Figure 2 For example, the feedback information for the second region 100b of the substrate 100 includes feedback information from the first film layer 110, the second film layer 120, and the third film layer 130. At this time, it is possible to determine whether there is a defect in the film layer in the region based on whether the echo information of each film layer matches the standard information of the corresponding film layer. If it is known that there is a defect in the region, the film layer where the defect is located can be further determined. Specifically, Figure 4 The graph of the standard information of the first film layer 110, the second film layer 120 and the third film layer 130 is shown in FIG. Figure 3 and Figure 4 As shown, the echo information (t1, Q1) of the first film layer 110 is compared with the corresponding first standard information (t1', Q1'), the echo information (t2, Q2) of the second film layer 120 is compared with the corresponding second standard information (t2', Q2'), and the echo information (t3, Q3) of the third film layer 130 is compared with the corresponding third standard information (t3', Q3'). When the echo information of each film layer matches the standard information of the corresponding film layer, it means that the film layer in that area is free of defects. If the echo information of a film layer does not match the corresponding standard information, it means that a defect exists in the film layer.

[0064] For example, Figure 2 and Figure 3 In the example, the collected echo information (t3, Q3) of the third film layer 130 matches the corresponding third standard information (t3', Q3'), but the echo information (t2, Q2) of the second film layer 120 deviates from the second standard information (t2', Q2'), and the echo information (t1, Q1) of the first film layer 110 deviates from the first standard information (t1', Q1'). It can be seen that there is a defect in the second film layer 120, which in turn causes abnormalities in the echo information fed back from the second film layer 120 and the first film layer 110.

[0065] In addition, it is possible to further determine whether there are defects in the corresponding film layer based on whether other intensity peaks are collected between adjacent echo times, such as Figure 3 In the example, an intensity peak Q4 is generated between t2 and t3. At this time, it can be inferred that there is a defect in the second film layer 120. The ultrasonic wave is partially reflected at the defect, thereby forming the defect intensity peak Q4. The height position of the defect in the second film layer 120 can also be determined based on the echo time corresponding to the defect intensity peak Q4. For example, Figure 3 Since the defect intensity peak Q4 is located between t2 and t3, close to t2, it can be determined that the height position of the defect corresponding to the defect intensity peak Q4 is located in the lower half of the second film layer 120 (i.e., close to the first film layer 110). In other words, in addition to determining whether a film layer has a defect and the film layer where the defect is located, the method of this patent can also determine the height position of the defect in the film layer where the defect is located by using the positional relationship between the defect intensity peak and the adjacent intensity peaks.

[0066] above Figure 3 The example of a defect in film layer 120 is used for description. However, when defects exist in film layer 110 or film layer 130, or both, defect intensity peaks Q5 and Q6 may be generated accordingly. Based on the defect intensity peaks, it is possible to determine whether there are defects in film layer 110 or 130 and the specific film layer where the defects are located. The height position of each defect in the film layer where the defect is located can also be determined by using the positional relationship between the defect intensity peak and the adjacent intensity peaks. Therefore, the method of this patent can realize the simultaneous detection of defects in multiple film layers. Through a single detection, it is possible to determine whether there are defects in multiple film layers, the film layer where each defect is located, and the height position of each defect in the film layer where the defect is located.

[0067] This embodiment also includes comparing the echo information from contact holes 210 / 220 with standard information corresponding to standard contact holes to determine whether contact holes 210 / 220 are defective. As described above, the contact holes to be formed sequentially penetrate each film layer above the target film layer and stop at the target film layer. Therefore, the standard information used to determine whether the contact holes are abnormal includes the echo information from the target film layer, but does not include the echo information of other film layers above the target film layer located to the side of the contact hole.

[0068] For example, Figure 2For example, the contact hole is expected to be formed by sequentially penetrating the third film layer 130 and the second film layer 120 and stopping at the first film layer 110. The corresponding standard information includes the echo information (t1, Q1) of the first film layer 110, but does not include the echo information of the second film layer 120 and the third film layer 130. During ultrasonic scanning, the echo information from contact hole 210 includes the echo information (t1, Q1) of the first film layer 110, but does not include the echo information of the second film layer 120 and the third film layer 130. This matches the corresponding standard information, indicating that the depth of contact hole 210 meets the expectations and contact hole 210 is normal. Furthermore, the echo information from contact hole 220 includes the echo information (t1, Q1) of the first film layer 110 and the echo information of the second film layer 120. This does not match the corresponding standard information, indicating that the depth of contact hole 220 does not meet the expectations and contact hole 220 is abnormal.

[0069] It should be noted that the standard information described above (including the standard information of each film layer and the standard information corresponding to the standard contact hole) can be obtained by ultrasonically scanning a standard substrate that meets the expectations. For example, a standard substrate can be provided, which has a first area with a standard contact hole formed thereon and a second area without a contact hole formed thereon. By scanning the standard substrate, echo information from the first area is obtained, which includes the standard information corresponding to the target film layer, but does not include the standard information of other film layers above the target film layer, so as to obtain the standard information of the target film layer. Figure 2 For example, the first standard information (t1', Q1') of the first film layer 110 is included, but the echo information of the second film layer 120 and the third film layer 130 is not included; the echo information from the second region includes the standard information of each film layer. Figure 2 For example, the first standard information ( t1 ′, Q1 ′) of the first film layer 110 , the second standard information ( t2 ′, Q2 ′) of the second film layer 120 , and the third standard information ( t3 ′, Q3 ′) of the third film layer 130 .

[0070] During the detection of the contact hole, the specific film layer where the bottom of the contact hole is located can be further inferred based on the echo information of the contact hole. For example, when the echo information from the contact hole includes the echo information of the first film layer 110 and the second film layer 120, it can be determined that the bottom of the contact hole stops in the second film layer 120, for example Figure 2 middle contact hole 220 .

[0071] In an optional example, the present invention can use ultrasound to simultaneously Figure 2The inspection of regions 100a and 100b in the image is performed together with other regions. The regions inspected together can include various graphic types, such as the film region 100b, the contact hole region 100a, or other regions. This allows for simultaneous inspection of multiple film layers and contact hole regions in a single inspection, improving the types of inspection regions and inspection efficiency. Furthermore, the defect types in different regions, the film layers where each defect is located, and the height position of each defect within the film layer where the defect is located can be determined based on the time information and intensity peak information of the echo.

[0072] In an optional example, when the entire surface of the substrate 100 needs to be inspected, the feedback information of the substrate 100 can be directly compared with the standard information of the standard substrate. When a partial area of ​​the substrate 100 needs to be inspected, the area to be inspected can be positioned to achieve accurate scanning of the area to be inspected. Specifically, the method for scanning and positioning the area to be inspected includes: selecting the coordinates (X, Y) of the product unit shot to be inspected; then, further determining the coordinates (X0, Y0) of the chip area to be inspected from the product unit shot; and then, defining the coordinates (X01, Y01) of the area to be inspected within the chip area.

[0073] It should be noted that in the above example, the first region 100a of the substrate 100 can be inspected for contact hole defects, and the second region 100b of the substrate 100 can be inspected for film layer defects. However, in other examples, only contact hole defects can be inspected, or only the presence of defects in the film layer can be determined.

[0074] In addition, Figure 2 In the example, the contact hole is not filled with a metal layer. In this case, the standard information of the corresponding standard contact hole includes the echo information of the target film layer, but does not include the echo information of other film layers above the target film layer. However, in other examples, the contact hole may be filled with a metal layer (for example, a metal layer including tungsten material). In this case, the echo information from the contact hole includes the echo information of the film layer at the bottom of the contact hole and the echo information of the metal layer. This information is compared with the standard information of the standard contact hole filled with a metal layer to confirm whether there is any abnormality.

[0075] The present disclosure also provides a defect detection system, which can implement the above-mentioned detection method. Figure 5 As shown, the detection system includes an ultrasonic detection device and a data processing unit (not shown in the figure), wherein the ultrasonic detection device is used to scan the substrate 100 and collect feedback information, and the data processing unit is used to compare the feedback information from the substrate 100 with the standard information to determine whether there is a defect.

[0076] Specifically, at least two film layers of different materials are stacked in sequence on the substrate 100. The feedback information obtained by scanning the substrate includes at least echo information from the film layer in a predetermined area, and the echo information of the film layer in the predetermined area is compared with the standard information of the corresponding film layer to determine whether there is a defect in the predetermined area.

[0077] The standard information for a film layer includes a standard echo time and a standard signal intensity collected within the standard echo time. The standard echo time and standard signal intensity are different for films made of different materials. During comparison, the data processing unit determines whether the echo time and signal intensity from the film to be tested matches the standard echo time and signal intensity of the corresponding film layer.

[0078] In one example, combining Figure 2 As shown, a contact hole 210 / 220 is formed in a predetermined region (e.g., the first region 100a) of the substrate 100. The contact hole 210 / 220 extends from the top film layer toward the target film layer below. At this point, the ultrasonic testing equipment is used to collect echo information from the film layer at the bottom of the contact hole. The data processing unit compares the echo information from the contact hole 210 / 220 with the standard information corresponding to a standard contact hole to determine whether the contact hole 210 / 220 is abnormal. Furthermore, during defect detection of the contact hole, the data processing unit can also be used to infer the specific film layer where the bottom of the contact hole 210 / 220 is located based on the echo information from the contact hole. The specific determination method can be referred to the above embodiment and will not be repeated here.

[0079] In another example, combining Figure 2 As shown, at least two film layers (e.g., a first film layer 110, a second film layer 120, and a third film layer 130) made of different materials are sequentially stacked within a predetermined region (e.g., the second region 100b) of the substrate 100. In this case, the ultrasonic testing device can be used to collect echo information from each film layer within the predetermined region and, using a data processing unit, compare the echo information of each film layer with standard information for the corresponding film layer to determine whether there are film defects within the predetermined region. The specific determination method can be referred to the above embodiment and will not be repeated here.

[0080] In another example, combining Figure 2 As shown, the substrate 100 has both a first region 100a and a second region 100b. In this case, the inspection system can be used to simultaneously inspect the defects of the contact holes and the defects of the film layer.

[0081] Continue to refer Figure 5As shown, the ultrasonic detection device includes an ultrasonic transmitter, which may include an excitation unit 3310 and a piezoelectric unit 330. The excitation unit 310 can be used to provide a required driving signal (e.g., an AC voltage of a predetermined frequency) and drive the piezoelectric unit 330 based on the driving signal, so that the piezoelectric unit 330 can generate a corresponding ultrasonic signal according to the driving signal. Optionally, the ultrasonic transmitter may also include a delay unit 320 to synchronize the ultrasonic signals between different ultrasonic transmitters, ensuring that the ultrasonic signals generated by each ultrasonic transmitter are aligned in time.

[0082] In summary, the defect detection method provided by the present disclosure, based on the knowledge that ultrasonic echo information differs for film layers of different materials, can determine whether a defect exists in a predetermined area based on whether the echo information of the film layers within the predetermined area matches the standard information of the corresponding film layers. For example, the presence of a film defect in a predetermined area can be determined based on whether the echo information of each film layer within the predetermined area matches the standard information of the corresponding film layer. Alternatively, the presence of a contact hole defect in the predetermined area can be determined based on the difference between the echo information of the film layer at the bottom of the contact hole within the predetermined area and the standard information of the film layer within the standard contact hole. Therefore, the defect detection method provided by the present disclosure can promptly detect the presence of defects on a substrate, which is conducive to improving product yield.

[0083] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. Although the present invention has been disclosed as above with preferred embodiments, the above embodiments are not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

[0084] It should also be understood that, unless otherwise specified or indicated, the terms "first," "second," "third," and the like in the specification are merely used to distinguish between various components, elements, steps, and the like in the specification, and are not used to indicate a logical or sequential relationship between the various components, elements, and steps. Furthermore, it should be recognized that the terms described herein are only used to describe specific embodiments and are not intended to limit the scope of the invention. It should be noted that the singular forms "a" and "an" used herein and in the appended claims include plural references unless the context clearly indicates otherwise. For example, a reference to "a step" or "a device" means a reference to one or more steps or devices, and may include secondary steps and secondary devices. All conjunctions used should be understood in their broadest sense. Furthermore, the word "or" should be understood to have the definition of a logical "or," not a logical "exclusive or," unless the context clearly indicates otherwise.

Claims

1. A defect detection method, characterized in that: include: Providing a substrate, on which at least two film layers of different materials are sequentially stacked; Scanning the substrate with ultrasonic waves and collecting feedback information, wherein the feedback information at least includes echo information from a film layer in a predetermined area; The echo information of the film layer in the predetermined area is compared with the standard information of the corresponding film layer to determine whether there is a defect in the predetermined area.

2. The defect detection method according to claim 1, characterized in that: A contact hole is formed in the predetermined area, and the contact hole extends from the top film layer toward the target film layer below; The feedback information includes echo information from the film layer at the bottom of the contact hole, and the echo information from the contact hole is compared with standard information corresponding to the film layer at the bottom of a standard contact hole to determine whether the contact hole has defects.

3. The defect detection method according to claim 2, characterized in that: Also includes: The specific film layer where the bottom of the contact hole is located is inferred based on the echo information from each film layer in the contact hole.

4. The defect detection method according to claim 3, characterized in that: The standard information corresponding to the standard contact hole includes the standard information corresponding to the target film layer, but does not include the standard information of other film layers located above the target film layer on the side of the standard contact hole; The detection method for the contact hole includes: Determining whether the echo information from the contact hole matches the standard information of the standard contact hole; If yes, then the contact hole has no abnormality; If not, the contact hole is abnormal, and the echo information of each film layer contained in the echo information of the contact hole is further analyzed to infer the specific film layer where the bottom of the contact hole is located.

5. The defect detection method according to claim 2, characterized in that: The contact hole is also filled with a metal layer; The echo information from the contact hole includes: echo information of the film layer at the bottom of the contact hole and echo information of the metal layer.

6. The defect detection method according to claim 1, characterized in that: At least two film layers made of different materials are sequentially stacked in the predetermined area; The feedback information includes echo information from each film layer within the predetermined area, and the echo information of each film layer is compared one by one with the standard information of the corresponding film layer to determine whether there is a defect in the film layer within the predetermined area, and / or the film layer where the defect is located, and / or the height position of the defect in the film layer where the defect is located.

7. The defect detection method according to claim 1, characterized in that: The substrate has a first region and a second region, a contact hole is formed in the first region, the contact hole extends from the top film layer toward the target film layer below, and no contact hole is formed in the second region; The feedback information includes: echo information from the film layer at the bottom of the contact hole in the first region; and echo information from each film layer in the second region.

8. The defect detection method according to claim 1, characterized in that: The method for acquiring the standard information of the film layer comprises: performing ultrasonic scanning on a standard substrate that meets expectations to obtain echo information of each film layer on the standard substrate, which is used to form the standard information of each film layer.

9. The defect detection method according to claim 8, characterized in that: The standard substrate has a first area and a second area, wherein a standard contact hole is formed in the first area, and no contact hole is formed in the second area, wherein the standard contact hole extends downward from the top film layer and stops on the target film layer; wherein The echo information from the first region includes: standard information corresponding to the target film layer, but does not include standard information of other film layers located above the target film layer at the side of the standard contact hole; The echo information from the second region includes: standard information of each film layer.

10. The defect detection method according to claim 1, characterized in that: The method for ultrasonically scanning the substrate comprises: filling a liquid film between an ultrasonic transmitting end and a surface of the substrate, so that the ultrasonic wave scans the substrate via the liquid film.

11. The defect detection method according to any one of claims 1 to 10, characterized in that: The standard information of the film layer includes the standard echo time and the standard signal strength collected within the standard echo time. The standard echo time and standard signal strength corresponding to the film layers of different materials are different. The method for comparing the echo information of the film layer in the predetermined area with the standard information of the corresponding film layer includes: determining whether the echo time and signal strength of the film layer in the predetermined area match the standard echo time and standard signal strength of the corresponding film layer.

12. A defect detection system, characterized in that: include: Ultrasonic detection equipment, used for scanning a substrate and collecting feedback information, wherein at least two layers of films made of different materials are sequentially stacked on the substrate, and the feedback information at least includes echo information from the film layers in a predetermined area; The data processing unit is used to compare the echo information of the film layer in the predetermined area with the standard information of the corresponding film layer to determine whether there is a defect in the predetermined area.

13. The defect detection system according to claim 12, characterized in that: A contact hole is formed in the predetermined area, and the contact hole extends from the top film layer toward the target film layer below; The ultrasonic detection device is used to collect echo information from the film layer at the bottom of the contact hole; The data processing unit is used to compare the echo information from the contact hole with the standard information corresponding to the film layer at the bottom of the standard contact hole to determine whether the contact hole is abnormal.

14. The defect detection system according to claim 13, characterized in that: The data processing unit is also used to infer the specific film layer where the bottom of the contact hole is located based on the echo information from the contact hole.

15. The defect detection system according to claim 12, characterized in that: At least two film layers made of different materials are sequentially stacked in the predetermined area; The ultrasonic detection equipment is used to collect echo information from each film layer in the predetermined area; The data processing unit is used to compare the echo information of each film layer with the standard information of the corresponding film layer one by one to determine whether there is a defect in the film layer in the predetermined area, and / or the film layer where the defect is located, and / or the height position of the defect in the film layer where the defect is located.

16. The defect detection system according to any one of claims 12 to 15, characterized in that: The standard information of the film layer includes the standard echo time and the standard signal strength collected within the standard echo time. The standard echo time and standard signal strength corresponding to the film layers of different materials are different. The data processing unit is used to determine whether the echo time and signal strength of the film layer in the predetermined area match the standard echo time and standard signal strength of the corresponding film layer.

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