Method for detecting a crack defect and detection system

Abstract

A crack defect detection method and a detection system, the crack defect detection method is used for detecting a crack defect in a passivation layer; the crack defect detection method comprises the following steps: performing deterioration treatment on a top passivation layer, so as to make a first type of crack in the passivation layer penetrate through the top passivation layer and expose a bottom passivation layer; performing a first corrosion treatment, so as to corrode the bottom passivation layer exposed by the first type of crack and the second type of crack in the passivation layer and expose a metal structure; performing a second corrosion treatment, so as to corrode the metal structure exposed by the first type of crack, the second type of crack and a third type of crack in the passivation layer; and detecting the crack based on a position of the metal structure corroded. The crack defect detection method and the detection system are beneficial to quickly, efficiently and accurately detecting the crack defect.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a method and system for detecting crack defects. Background Technology

[0002] With the development trend of very large-scale integrated circuits (VLSI), the feature size of integrated circuits continues to shrink, and the requirements for integrated circuit packaging technology are also constantly increasing. Existing packaging technologies include ball grid array (BGA), chip scale package (CSP), wafer level package (WLP), 3D packaging, and system in package (SiP).

[0003] With the continuous development of packaging technology, the diversification of packaging forms has brought severe challenges to chip packaging reliability. Passivation layers may develop cracks due to stress concentration during the manufacturing process, and these cracks will continue to worsen during subsequent environmental testing, seriously affecting chip reliability.

[0004] However, it is currently impossible to effectively and promptly detect the micro-cracks present in the passivation layer. Summary of the Invention

[0005] The problem solved by the embodiments of the present invention is to provide a method and system for detecting crack defects, which is beneficial for rapid, efficient and accurate detection of crack defects.

[0006] To address the aforementioned problems, this invention provides a method for detecting crack defects in a passivation layer. The passivation layer includes a bottom passivation layer covering the top surface and sidewalls of a metal structure, and a top passivation layer situated on top of the bottom passivation layer. The crack defects in the passivation layer include one or more of a first type of crack, a second type of crack, and a third type of crack. The first type of crack penetrates a portion of the thickness of the top passivation layer; the second type of crack penetrates both the top passivation layer and a portion of the thickness of the bottom passivation layer; and the third type of crack penetrates both the top passivation layer and the bottom passivation layer. The method for detecting crack defects includes: applying a passivation layer to the top passivation layer... The passivation layer undergoes a deterioration treatment to allow a first type of crack to penetrate the top passivation layer when a first type of crack exists in the passivation layer, thereby exposing the bottom passivation layer. A first corrosion treatment is performed to etch the bottom passivation layer exposed by the first and second types of cracks when a first type of crack and a second type of crack exist in the passivation layer, thereby exposing the metal structure. A second corrosion treatment is performed to etch the metal structure exposed by the first, second, and third types of cracks when a first type of crack, a second type of crack, and a third type of crack exist in the passivation layer. The cracks are detected based on their locations within the etched metal structure.

[0007] Optionally, the crack defect detection method is performed after the passivation layer is formed and before the encapsulation process.

[0008] Optionally, the crack defect detection method can be used during the unsealing analysis.

[0009] Optionally, the metal structure includes metal wires.

[0010] Optionally, the material of the metal structure includes one or more of aluminum, copper, cobalt, tungsten, and nickel.

[0011] Optionally, the step of detecting the crack based on the location of corrosion of the metal structure includes: after performing the second corrosion treatment, locating the location of corrosion of the metal structure using an optical microscope.

[0012] Optionally, the deterioration treatment process includes heat treatment.

[0013] Optionally, the heat treatment includes a thermal cycling test.

[0014] Optionally, the parameters of the thermal cycling test include: a temperature range of -65°C to 150°C, and a cycle time of 15 to 60 minutes.

[0015] Optionally, the first corrosion treatment step includes: using a first etchant to perform a first corrosion treatment on the bottom passivation layer exposed by the first type of crack and the second type of crack.

[0016] Optionally, the material of the bottom passivation layer includes silicon oxide; the first etching solution includes a mixed solution of acetic acid and ammonium fluoride.

[0017] Optionally, the first etching process may take 20 to 40 seconds.

[0018] Optionally, the second corrosion treatment step includes: using a second etching solution to perform a second corrosion treatment on the metal structure exposed by the first type of crack, the second type of crack, and the third type of crack.

[0019] Optionally, the material of the metal structure includes aluminum; the second etching solution includes a hydrochloric acid solution.

[0020] Optionally, the second etching process may take 5 to 10 minutes.

[0021] Accordingly, embodiments of the present invention also provide a crack defect detection system for detecting crack defects in a passivation layer. The passivation layer includes a bottom passivation layer covering the top surface and sidewalls of a metal structure and a top passivation layer located on the bottom passivation layer. The crack defects in the passivation layer include one or more of a first type of crack, a second type of crack, and a third type of crack. The first type of crack penetrates a portion of the thickness of the top passivation layer, the second type of crack penetrates the top passivation layer and a portion of the thickness of the bottom passivation layer, and the third type of crack penetrates both the top passivation layer and the bottom passivation layer. The crack defect detection system includes a passivation layer deterioration module for performing deterioration treatment on the top passivation layer, suitable for detecting crack defects in the passivation layer when... When the top passivation layer has a first type of crack, the first type of crack penetrates the top passivation layer to expose the bottom passivation layer; a first corrosion module is used to perform a first corrosion treatment, adapted to corrode the bottom passivation layer exposed by the first and second type cracks when the passivation layer has a first type of crack and a second type of crack, to expose the metal structure; a second corrosion module is used to perform a second corrosion treatment when the passivation layer has a first type of crack, a second type of crack, and a third type of crack, adapted to corrode the metal structure exposed by the first, second, and third type of cracks; a detection module is used to detect the cracks based on the location of the corrosion on the metal structure.

[0022] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages: The crack defect detection method provided in this invention, through deterioration treatment, first corrosion treatment, and second corrosion treatment, can corrode the metal structure at the location of a first type of crack; through the first and second corrosion treatments, it can corrode the metal structure at the location of a second type of crack; and through the second corrosion treatment, it can corrode the metal structure at the location of a third type of crack. Therefore, this invention can not only detect minor crack defects that do not completely penetrate the passivation layer, improving the accuracy and effectiveness of crack defect detection, but also identify cracks of different severity and reliability risks using different steps. Furthermore, by performing deterioration treatment, first corrosion treatment, and second corrosion treatment on the top passivation layer, this invention can corrode the metal structure below the crack defect when a crack defect exists in the passivation layer. This facilitates the location of the crack defect based on the location of the corroded metal structure, which is beneficial for rapid, efficient, and accurate crack defect detection. In addition, in the actual detection process, different types of crack defects can be identified by selecting different steps.

[0023] In an alternative approach, the crack defect detection method is performed after the passivation layer is formed and before the packaging process, thereby detecting crack defects before packaging. This helps reduce invalid packaging and subsequent reliability testing, and consequently saves costs. Attached Figure Description

[0024] Figure 1 Schematic diagrams of two packaging structures are shown; Figure 2 This is an electron microscope image of a crack defect inside a passivation layer; Figure 3 This is a schematic flowchart of an embodiment of the crack defect detection method of the present invention; Figure 4 This is a schematic diagram of an embodiment of the passivation layer and the metal structure; Figure 5 This is a schematic diagram of three types of crack defects; Figures 6 to 8 This is a schematic diagram of the structure corresponding to each step in one embodiment of the crack defect detection method of the present invention; Figure 9 This is a top-view schematic diagram of a metal structure under an optical microscope; Figure 10 This is a functional block diagram of the crack defect detection system of the present invention. Detailed Implementation

[0025] As can be seen from the background technology, with the continuous development of packaging technology, the diversified packaging forms have brought severe challenges to the reliability of chip packaging. At present, it is impossible to effectively and timely detect the micro-cracks in the passivation layer.

[0026] We will now combine two packaging structures to analyze why it is impossible to effectively and timely detect the micro-cracks in the passivation layer.

[0027] refer to Figure 1 The diagram shows two schematic representations of the packaging structure. Figure 1 (a) shows a schematic diagram of a flip-chip-scale package or a flip-chip ball grid array package. Figure 1 (b) shows a schematic diagram of a wafer-level packaging structure.

[0028] like Figure 1 As shown in (a), chip 11 is bonded to substrate 10; as Figure 1 As shown in (b), multiple chips 12 are located on a wafer and are packaged at the wafer level.

[0029] In the semiconductor field, after the fabrication of multilayer metal lines in the back-end processes, a metal structure (not shown) and a passivation layer (not shown) covering both the metal structure and the chip surface are typically formed on the top surface of the chip. At the right-angle corners of the metal structure, stress concentration is prone to occur. Consequently, the passivation layer formed at these corners is susceptible to stress, potentially leading to cracks within the passivation layer (e.g., ...). Figure 2 (As shown in the dashed box A). Cracks and defects appearing inside the passivation layer will continue to worsen during subsequent high-temperature, high-pressure, and high-humidity environmental tests, leading to a decrease in chip reliability.

[0030] Currently, destructive physical analysis (DPA) is usually performed after environmental testing fails following encapsulation. However, this method cannot detect micro-cracks in the passivation layer in advance, leading to ineffective encapsulation and testing, wasting human and material resources, and potentially increasing costs.

[0031] Furthermore, due to the complexity of actual chip design and the minute size of cracks, they cannot be observed through optical microscopes. Therefore, they are usually carefully observed through high-magnification scanning electron microscopy (SEM), which greatly increases the workload and cannot quickly locate and detect cracks, easily consuming manpower and wasting a lot of SEM machine time.

[0032] Another detection method involves corroding the metal structure. If cracks exist in the passivation layer, the corrosive liquid will corrode the metal structure along the cracks. By observing the location of the corrosion, the cracks can be located. However, this method cannot detect tiny cracks that have not completely penetrated the passivation layer but pose a reliability risk.

[0033] To address the aforementioned technical problem, embodiments of the present invention provide a method for detecting crack defects in a passivation layer, wherein the passivation layer includes a bottom passivation layer covering the top surface and sidewalls of a metal structure and a top passivation layer located on the bottom passivation layer.

[0034] The crack defects in the passivation layer include one or more of the following: first type cracks, second type cracks, and third type cracks. The first type cracks penetrate a portion of the thickness of the top passivation layer, the second type cracks penetrate the top passivation layer and a portion of the thickness of the bottom passivation layer, and the third type cracks penetrate the top passivation layer and the bottom passivation layer.

[0035] refer to Figure 3 The diagram shows a flowchart of one embodiment of the crack defect detection method of the present invention.

[0036] In this embodiment, the method for detecting crack defects includes the following basic steps: Step S1: The top passivation layer is degraded to allow the first type of crack to penetrate the top passivation layer when there is a first type of crack in the passivation layer, thereby exposing the bottom passivation layer. Step S2: Perform a first etching treatment to etch the bottom passivation layer exposed by the first and second type of cracks when there are first and second type cracks in the passivation layer, so as to expose the metal structure. Step S3: Perform a second corrosion treatment to corrode the metal structure exposed by the first, second, and third type of cracks when there are first, second, and third type cracks in the passivation layer; Step S4: Detect the cracks based on the location of corrosion on the metal structure.

[0037] The crack defect detection method provided in this invention, through deterioration treatment, first corrosion treatment, and second corrosion treatment, can corrode the metal structure at the location of a first type of crack; through the first and second corrosion treatments, it can corrode the metal structure at the location of a second type of crack; and through the second corrosion treatment, it can corrode the metal structure at the location of a third type of crack. Therefore, this invention can not only detect minor crack defects that do not completely penetrate the passivation layer, improving the accuracy and effectiveness of crack defect detection, but also identify cracks of different severity and reliability risks using different steps. Furthermore, by performing deterioration treatment, first corrosion treatment, and second corrosion treatment on the top passivation layer, this invention can corrode the metal structure below the crack defect when a crack defect exists in the passivation layer. This facilitates the location of the crack defect based on the location of the corroded metal structure, which is beneficial for rapid, efficient, and accurate crack defect detection. In addition, in the actual detection process, different types of crack defects can be identified by selecting different steps.

[0038] To make the above-mentioned objects, features and advantages of the embodiments of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Figures 6 to 8 This is a schematic diagram of the structure corresponding to each step in one embodiment of the crack defect detection method of the present invention.

[0039] In this embodiment, the crack defect detection method is used to detect crack defects in the passivation layer.

[0040] Reference Figure 4 The diagram shows a schematic representation of an embodiment of the passivation layer and the metal structure.

[0041] like Figure 4 As shown, the passivation layer 100 includes a bottom passivation layer 110 covering the top surface and sidewalls of the metal structure 130 and a top passivation layer 120 located on the bottom passivation layer 110.

[0042] In this embodiment, the metal structure 130 includes metal lines. The metal lines are used to implement wiring on the chip to meet circuit design requirements.

[0043] As an example, the material of the metal structure 130 includes one or more of aluminum, copper, cobalt, tungsten, and nickel. In this embodiment, aluminum is used as an example material for the metal structure 130.

[0044] The passivation layer 100 is located on the surface of the chip and serves to protect the internal structure of the chip, as well as the metal structure 130.

[0045] In this embodiment, the passivation layer 100 is a multi-layer structure, including a bottom passivation layer 110 covering the top surface and sidewalls of the metal structure 130 and a top passivation layer 120 located on the bottom passivation layer 110.

[0046] In this embodiment, the bottom passivation layer 110 is made of silicon oxide, and the top passivation layer 120 is made of silicon nitride.

[0047] In the semiconductor field, stress concentration is prone to occur at the right-angle corner of the metal structure 130. The passivation layer 100 formed at the right-angle corner of the metal structure 130 is easily affected by stress, which in turn makes it easy for cracks to appear inside the passivation layer 100.

[0048] Reference Figure 5 The diagram shows three types of crack defects.

[0049] As an example, the crack defects in the passivation layer 100 include first-type cracks 201 (such as...). Figure 5 (a) shown), second type of crack 202 (as shown in the image) Figure 5 (b) and third-type crack 203 (as shown in the image) Figure 5 (c) shows one or more of the following: the first type of crack 201 penetrates a portion of the thickness of the top passivation layer 120; the second type of crack 202 penetrates the top passivation layer 120 and a portion of the thickness of the bottom passivation layer 110; and the third type of crack 203 penetrates the top passivation layer 120 and the bottom passivation layer 110.

[0050] Among them, the first type of crack 201 and the second type of crack 203 are minor crack defects with small depth that do not completely penetrate the passivation layer 100, but they still pose a reliability risk and are usually difficult to detect accurately using traditional detection methods.

[0051] In this embodiment, the method for detecting crack defects includes: refer to Figure 3 and Figure 6 ,in, Figure 6 The diagram shows the structure of the passivation layer after the degradation treatment. Step S1 is performed: the top passivation layer 120 is degraded so that when there is a first type of crack 201 in the passivation layer 120, the first type of crack 201 penetrates the top passivation layer 120 to expose the bottom passivation layer 110.

[0052] The deterioration treatment is used to further induce cracking of the top passivation layer 120, thereby completely cracking the top passivation layer 120 to expose the bottom passivation layer 110, which facilitates subsequent first corrosion treatment of the bottom passivation layer 110 through the first type of crack 201 penetrating the top passivation layer 120.

[0053] As an example, the deterioration process includes heat treatment. During heat treatment, stress in the top passivation layer 120 can be released, thereby accelerating the cracking of the first type of crack 201 so that the first type of crack 201 can completely penetrate the top passivation layer 120 after the deterioration process.

[0054] As a specific embodiment, the heat treatment includes a thermal cycling test (TCT). During the thermal cycling test, the sample is exposed to an environment of alternating high and low temperatures. The sample undergoes a cycle from low temperature to high temperature in a short period of time, which can accelerate the exposure of stress defects inside the component caused by problems such as mismatch in the thermal expansion coefficients of the materials. This can accelerate the cracking of the first type of crack 201 in the top passivation layer 120, so that the first type of crack 201 after the thermal cycling test can completely penetrate the top passivation layer 120.

[0055] In this embodiment, the parameters of the thermal cycling test include: a temperature range of -65°C to 150°C, and a cycle time of 15 to 60 minutes.

[0056] By setting the temperature variation range to -65℃ to 150℃, the top passivation layer 120 can be exposed to low and high temperature environments, and the large temperature variation range is beneficial to significantly accelerate the cracking of the first type of crack 201 in the top passivation layer 120.

[0057] It should be noted that during the thermal cycling test, the duration of each cycle should not be too short or too long. If the duration of each cycle is too short, the temperature variation range will be insufficient to meet the process requirements; if the duration of each cycle is too long, it will easily increase the time required for deterioration treatment, thus wasting time. Therefore, in this embodiment, the duration of each cycle is 15 to 60 minutes.

[0058] In other embodiments, based on actual process requirements, other suitable methods may be used for deterioration treatment.

[0059] It should be noted that in specific implementation, when there are second-type cracks 202 in the passivation layer 100, during the deterioration process, the second-type cracks 202 will also crack more, and may even directly expose the metal structure 130.

[0060] refer to Figure 3 and Figure 7 Step S2: Perform a first corrosion treatment to corrode the bottom passivation layer 110 exposed by the first type of crack 201 and the second type of crack 202 when there are first type of crack 201 and second type of crack 202 in the passivation layer 100, so as to expose the metal structure 130.

[0061] The metal structure 130 is exposed so that it can be corroded.

[0062] As an example, the first corrosion treatment step includes: using a first etchant to perform a first corrosion treatment on the bottom passivation layer 110 exposed by the first type of crack 201 and the second type of crack 202. The first etchant can penetrate into the first type of crack 201 and the second type of crack 202, thereby corroding the bottom passivation layer 110.

[0063] More specifically, the sample is immersed in the first etching solution to perform a first etching treatment on the bottom passivation layer exposed by the first type of crack 201 and the second type of crack 202.

[0064] In this embodiment, the material of the bottom passivation layer 110 includes silicon oxide; the first etching solution includes a mixed solution of acetic acid (CH3COOH) and ammonium fluoride (NH4F).

[0065] As a specific embodiment, the volume percentage concentration of CH3COOH in the first corrosive solution is 32%, and the volume percentage concentration of NH4F is 13%.

[0066] In other embodiments, when the material of the bottom passivation layer is other materials, other suitable first etchant is selected to etch the bottom passivation layer.

[0067] It should be noted that the time for the first etching process should not be too short or too long. If the first etching process is too short, it is easy to increase the probability that the bottom passivation layer 110 exposed by the crack will not be completely etched away, which in turn increases the probability that the metal structure 130 will not be exposed. If the first etching process is too long, it is easy to waste process time. Therefore, in this embodiment, the time for the first etching process is 20 to 40 seconds.

[0068] refer to Figure 3 and Figure 8 Step S3: Perform a second corrosion treatment to corrode the metal structure 130 exposed by the first type of crack 201, the second type of crack 202 and the third type of crack 203 when the passivation layer 100 has a first type of crack 201, a second type of crack 202 and a third type of crack 203.

[0069] The corrosion exposes the metal structure 130 so that cracks can be located and detected based on the location of the corrosion on the metal structure 130.

[0070] In this embodiment, the metal structure 130 at the location of the first type of crack 201 can be corroded through deterioration treatment, first corrosion treatment, and second corrosion treatment; the metal structure 130 at the location of the second type of crack 202 can be corroded through the first corrosion treatment and second corrosion treatment; and the metal structure 130 at the location of the third type of crack 201 can be corroded through the second corrosion treatment. Therefore, based on the location of the corrosion of the metal structure 130, the crack can be detected, which not only can minor crack defects that have not completely penetrated the passivation layer 100 be detected, improving the accuracy and effectiveness of crack defect detection, but also can use different steps to identify cracks of different severity and with reliability risks.

[0071] Furthermore, this embodiment performs a deterioration treatment, a first corrosion treatment, and a second corrosion treatment on the top passivation layer 120, so that when there is a crack defect in the passivation layer 100, the metal structure 130 below the crack defect can be corroded. This facilitates the location of the crack defect based on the location of the corrosion of the metal structure 130, which is beneficial for the rapid, efficient, and accurate detection of crack defects.

[0072] In addition, different types of crack defects can be identified by selecting different steps during the actual testing process.

[0073] For example, in the actual testing process, if a crack defect can only be detected after the first and second corrosion treatment steps, it can be identified as a second type of crack 202; or, it can be selected to perform only the second corrosion treatment step. If a crack defect is detected at this time, the crack defect is a third type of crack 203; or, if a crack defect can only be detected after the deterioration treatment, the first corrosion treatment, and the second corrosion treatment steps, it can be identified as a first type of crack 201.

[0074] In this embodiment, the step of performing the second corrosion treatment includes: using a second corrosion solution to perform a second corrosion treatment on the metal structure 130 exposed by the first type of crack 201, the second type of crack 202 and the third type of crack 203.

[0075] Specifically, the second corrosive liquid can enter the first type of crack 201, the second type of crack 202 and the third type of crack 203, come into contact with the exposed metal structure 130, and then perform a second corrosion treatment on the exposed metal structure 130.

[0076] More specifically, the sample is immersed in a second etching solution to perform a second etching treatment on the metal structure 130 exposed by the first type of crack 201, the second type of crack 202, and the third type of crack 203.

[0077] In this embodiment, the material of the metal structure 130 includes aluminum; the second etching solution includes hydrochloric acid solution.

[0078] As a specific embodiment, the volume percentage concentration of the hydrochloric acid solution is 25%.

[0079] In other embodiments, when the material of the metal structure is other than other materials, other suitable second etchants are selected to etch the metal structure.

[0080] It should be noted that the time for the second etching treatment should not be too short or too long. If the second etching treatment time is too short, the metal structure 130 may not be etched or the etched area may be too small, which will increase the difficulty of subsequent crack detection based on the location of the etched metal structure 130. If the second etching treatment time is too long, it will waste process time. Therefore, in this embodiment, the time for the second etching treatment is 5 to 10 minutes.

[0081] refer to Figure 3 Step S4: Detect the cracks based on the location of corrosion on the metal structure 130.

[0082] Based on the location of corrosion of the metal structure 130, the cracks are detected, which not only improves the accuracy and effectiveness of crack defect detection by detecting minor cracks that have not completely penetrated the passivation layer 100, but also allows for the use of different steps to identify cracks of different severity and with reliability risks.

[0083] Furthermore, this embodiment performs a deterioration treatment, a first corrosion treatment, and a second corrosion treatment on the top passivation layer 120, so that when there is a crack defect in the passivation layer 100, the metal structure 130 below the crack defect can be corroded. This facilitates the location of the crack defect based on the location of the corrosion of the metal structure 130, which is beneficial for the rapid, efficient, and accurate detection of crack defects.

[0084] Specifically, cracks are usually quite small. Compared with direct observation of cracks, locating crack defects based on the location of corrosion of the metal structure 130 can magnify the defects at the crack location, making it easier to observe the location of corrosion of the metal structure 130 and thus facilitating the rapid and efficient location of crack defects.

[0085] In this embodiment, the step of detecting cracks based on the location of corrosion of the metal structure 130 includes: after performing the second corrosion treatment, using an optical microscope to locate the location of corrosion of the metal structure 130.

[0086] Specifically, the area of ​​the corroded region of the metal structure 130 is usually large, so that the location of the corrosion of the metal structure 130 can be located using an optical microscope. The operation is simple and can be completed in a general chemical laboratory.

[0087] Reference Figure 9 This shows a top-view schematic diagram of the metal structure 130 under an optical microscope. Figure 9 (a) shows a top view of the metal structure 130 before the deterioration treatment, the first corrosion treatment, and the second corrosion treatment. Figure 9 (b) shows a top view of the metal structure 130 after the deterioration treatment, the first corrosion treatment, and the second corrosion treatment.

[0088] like Figure 9 As shown, before the deterioration treatment, the first corrosion treatment, and the second corrosion treatment, the cracks were barely visible under an optical microscope. After the deterioration treatment, the first corrosion treatment, and the second corrosion treatment, the corroded location 200 of the metal structure 130 could be clearly and obviously observed under an optical microscope, thus facilitating the rapid and accurate location of the crack defects.

[0089] Accordingly, in specific implementations, after locating the corroded position of the metal structure 130 using an optical microscope, if necessary, an electron scanning microscope can also be used to observe the corroded position of the metal structure 130 to further observe the crack defects in the passivation layer 100 at that location.

[0090] It should be noted that the passivation layer 100 is transparent under an optical microscope; therefore, in... Figure 9 Only the metal structure 130 is shown in the diagram.

[0091] It should also be noted that in this embodiment, the crack defect detection method is performed after the passivation layer 100 is formed and before entering the packaging process. This allows for the detection of crack defects before packaging, which helps reduce invalid packaging and subsequent reliability testing, and consequently saves costs. In other embodiments, the crack defect detection method can also be performed during the depackaging analysis process.

[0092] Accordingly, the present invention also provides a crack defect detection system. Figure 10 This is a functional block diagram of an embodiment of the crack defect detection system of the present invention.

[0093] In this embodiment, the crack defect detection system is used to detect crack defects in the passivation layer.

[0094] Reference Figure 4 The diagram shows a schematic representation of an embodiment of the passivation layer and the metal structure.

[0095] like Figure 4 As shown, the passivation layer 100 includes a bottom passivation layer 110 covering the top surface and sidewalls of the metal structure 130 and a top passivation layer 120 located on the bottom passivation layer 110.

[0096] In this embodiment, the metal structure 130 includes metal lines. The metal lines are used to implement wiring on the chip to meet circuit design requirements. As an example, the material of the metal structure 130 includes one or more of aluminum, copper, cobalt, tungsten, and nickel. In this embodiment, aluminum is used as an example material for the metal structure 130.

[0097] The passivation layer 100 is located on the surface of the chip and serves to protect the internal structure of the chip, as well as the metal structure 130.

[0098] In this embodiment, the passivation layer 100 is a multi-layer structure, including a bottom passivation layer 110 covering the top surface and sidewalls of the metal structure 130 and a top passivation layer 120 located on the bottom passivation layer 110.

[0099] In this embodiment, the bottom passivation layer 110 is made of silicon oxide, and the top passivation layer 120 is made of silicon nitride.

[0100] In the semiconductor field, stress concentration is prone to occur at the right-angle corner of the metal structure 130. Consequently, the passivation layer formed at the right-angle corner of the metal structure 130 is easily affected by stress, which in turn makes it easy for cracks to appear inside the passivation layer 100.

[0101] Reference Figure 5 The diagram shows three types of crack defects.

[0102] As an example, the crack defects in the passivation layer 100 include first-type cracks 201 (such as...). Figure 5 (a) shown), second type of crack 202 (as shown in the image) Figure 5 (b) and third-type crack 203 (as shown in the image) Figure 5 (c) shows one or more of the following: the first type of crack 201 penetrates a portion of the thickness of the top passivation layer 120; the second type of crack 202 penetrates the top passivation layer 120 and a portion of the thickness of the bottom passivation layer 110; and the third type of crack 203 penetrates the top passivation layer 120 and the bottom passivation layer 110.

[0103] Among them, the first type of crack 201 and the second type of crack 203 are minor crack defects with small depth that do not completely penetrate the passivation layer 100, but they still pose a reliability risk and are usually difficult to detect accurately using traditional detection methods.

[0104] refer to Figure 10 In this embodiment, the crack defect detection system 30 includes: a passivation layer deterioration module 31, used to deteriorate the top passivation layer 120, adapted to allow the first type of crack 201 to penetrate the top passivation layer 120 when there is a first type of crack 201 in the top passivation layer 120, so as to expose the bottom passivation layer 110; and a first corrosion module 32, used to perform a first corrosion treatment, adapted to corrode the first type of crack when there is a first type of crack 201 and a second type of crack 202 in the passivation layer 100. The bottom passivation layer 110 exposed by the first type of crack 201 and the second type of crack 202 exposes the metal structure 130; the second corrosion module 33 is used to perform a second corrosion treatment when the passivation layer 100 has the first type of crack 201, the second type of crack 202 and the third type of crack 203, and is suitable for corroding the metal structure 130 exposed by the first type of crack 201, the second type of crack 202 and the third type of crack 203; the detection module 34 is used to detect the cracks based on the location of corrosion of the metal structure 130.

[0105] In the crack defect detection system 30, the passivation layer deterioration module 31, the first corrosion module 32 and the second corrosion module 33 can corrode the metal structure 130 at the location of the first type of crack 201; the first corrosion module 32 and the second corrosion module 33 can corrode the metal structure 130 at the location of the second type of crack 202; and the second corrosion module 33 can corrode the metal structure 130 at the location of the third type of crack 203.

[0106] Therefore, the detection system provided in this embodiment can not only detect minor crack defects that do not completely penetrate the passivation layer 100, improving the accuracy and effectiveness of crack defect detection, but also use different steps to identify cracks of different severity and with reliability risks.

[0107] Furthermore, this embodiment utilizes the passivation layer deterioration module 31, the first corrosion module 32, and the second corrosion module 33 to corrode the metal structure 130 below the crack defect when a crack defect exists in the passivation layer 100. This facilitates the detection module 34 in locating the crack defect based on the location of the corrosion of the metal structure 130, which is beneficial for rapid, efficient, and accurate detection of crack defects.

[0108] In addition, different types of crack defects can be identified by selecting different steps during the actual testing process.

[0109] Reference Figure 6The passivation layer deterioration module 31 is used to further induce cracking of the top passivation layer 120, thereby completely cracking the top passivation layer 120 to expose the bottom passivation layer 110, which facilitates subsequent first corrosion treatment of the bottom passivation layer 110 through the first type of crack 201 penetrating the top passivation layer 120.

[0110] As an example, the deterioration process includes heat treatment. During heat treatment, stress in the top passivation layer 120 can be released, thereby accelerating the cracking of the first type of crack 201 so that the first type of crack 201 can completely penetrate the top passivation layer 120 after the deterioration process.

[0111] As a specific embodiment, the heat treatment includes a thermal cycling test (TCT). During the thermal cycling test, the sample is exposed to an environment of alternating high and low temperatures. The sample undergoes a cycle from low temperature to high temperature in a short period of time, which can accelerate the exposure of stress defects inside the component caused by problems such as mismatch in the thermal expansion coefficients of the materials. This can accelerate the cracking of the first type of crack 201 in the top passivation layer 120, so that the first type of crack 201 after the thermal cycling test can completely penetrate the top passivation layer 120.

[0112] In this embodiment, the parameters of the thermal cycling test include: a temperature range of -65°C to 150°C, and a cycle time of 15 to 60 minutes.

[0113] By setting the temperature variation range to -65℃ to 150℃, the top passivation layer 120 can be exposed to low and high temperature environments, and the large temperature variation range is beneficial to significantly accelerate the cracking of the first type of crack 201 in the top passivation layer 120.

[0114] It should be noted that during the thermal cycling test, the duration of each cycle should not be too short or too long. If the duration of each cycle is too short, the temperature variation range will be insufficient to meet the process requirements; if the duration of each cycle is too long, it will easily increase the time required for deterioration treatment, thus wasting time. Therefore, in this embodiment, the duration of each cycle is 15 to 60 minutes.

[0115] In other embodiments, based on actual process requirements, other suitable methods may be used for deterioration treatment.

[0116] It should be noted that in specific implementation, when there are second-type cracks 202 in the passivation layer 100, during the deterioration process, the second-type cracks 202 will also crack more, and may even directly expose the metal structure 130.

[0117] Reference Figure 7The first corrosion module 32 performs a first corrosion treatment to corrode the bottom passivation layer 110 exposed by the first type of crack 201 and the second type of crack 202 when there are first type of crack 201 and second type of crack 202 in the passivation layer 100, so as to expose the metal structure 130, so that the second corrosion module 33 can perform corrosion treatment on the exposed metal structure 130.

[0118] As an example, a first etchant is used to perform a first etching treatment on the bottom passivation layer 110 exposed by the first type of crack 201 and the second type of crack 202. The first etchant can penetrate into the first type of crack 201 and the second type of crack 202, thereby etching the bottom passivation layer 110.

[0119] More specifically, the sample is immersed in the first etching solution to perform a first etching treatment on the bottom passivation layer 110 exposed by the first type of crack 201 and the second type of crack 202.

[0120] In this embodiment, the material of the bottom passivation layer 110 includes silicon oxide; the first etching solution includes a mixed solution of acetic acid (CH3COOH) and ammonium fluoride (NH4F).

[0121] As a specific embodiment, the volume percentage concentration of CH3COOH in the first corrosive solution is 32%, and the volume percentage concentration of NH4F is 13%.

[0122] In other embodiments, when the material of the bottom passivation layer is other materials, other suitable first etchant is selected to etch the bottom passivation layer.

[0123] It should be noted that the time for the first etching process should not be too short or too long. If the first etching process is too short, it is easy to increase the probability that the bottom passivation layer 110 exposed by the crack will not be completely etched away, which in turn increases the probability that the metal structure 130 will not be exposed. If the first etching process is too long, it is easy to waste process time. Therefore, in this embodiment, the time for the first etching process is 20 to 40 seconds.

[0124] Reference Figure 8 The second corrosion module 33 is used to corrode the metal structure 130 exposed by the first type of crack 201, the second type of crack 202, and the third type of crack 203 when there are first type of crack 201, second type of crack 202, and third type of crack 203 in the passivation layer 100, so that the detection module 33 can locate the cracks based on the location of corrosion of the metal structure 130, so as to detect the cracks.

[0125] In this embodiment, the passivation layer deterioration module 31, the first corrosion module 32, and the second corrosion module 33 can corrode the metal structure 130 at the location of the first type of crack 201; the first corrosion module 32 and the second corrosion module 33 can corrode the metal structure 130 at the location of the second type of crack 202; and the second corrosion module 33 can corrode the metal structure 130 at the location of the third type of crack 201. Therefore, the detection module 34 detects the cracks based on the location of the corrosion of the metal structure 130. This not only allows for the detection of minor crack defects that have not completely penetrated the passivation layer 100, improving the accuracy and effectiveness of crack defect detection, but also enables the identification of cracks of different severity and with reliability risks using different steps.

[0126] Furthermore, this embodiment performs a deterioration treatment, a first corrosion treatment, and a second corrosion treatment on the top passivation layer 120, so that when there is a crack defect in the passivation layer 100, the metal structure 130 below the crack defect can be corroded. This facilitates the location of the crack defect based on the location of the corrosion of the metal structure 130, which is beneficial for the rapid, efficient, and accurate detection of crack defects.

[0127] In addition, different types of crack defects can be identified by selecting different steps during the actual testing process.

[0128] For example, in the actual testing process, if crack defects can only be detected through the first corrosion module 32 and the second corrosion module 33, then it can be determined to be a second type of crack 202; or, it can be selected that crack defects are detected only through the second corrosion module 33, then the crack defects are third type of crack 203; or, if crack defects can only be detected through the passivation layer deterioration module 31, the first corrosion module 32 and the second corrosion module 33, then it can be determined to be a first type of crack 201.

[0129] In this embodiment, a second etching solution is used to perform a second etching treatment on the metal structure 130 exposed by the first type of crack 201, the second type of crack 202, and the third type of crack 203.

[0130] Specifically, the second corrosive liquid can enter the first type of crack 201, the second type of crack 202 and the third type of crack 203, come into contact with the exposed metal structure 130, and then perform a second corrosion treatment on the exposed metal structure 130.

[0131] More specifically, the sample is immersed in a second etching solution to perform a second etching treatment on the metal structure 130 exposed by the first type of crack 201, the second type of crack 202, and the third type of crack 203.

[0132] In this embodiment, the material of the metal structure 130 includes aluminum; the second etching solution includes a hydrochloric acid solution.

[0133] As a specific embodiment, the volume percentage concentration of the hydrochloric acid solution is 25%.

[0134] In other embodiments, when the material of the metal structure is other than other materials, other suitable second etchants are selected to etch the metal structure.

[0135] It should be noted that the time for the second etching treatment should not be too short or too long. If the second etching treatment time is too short, the metal structure 130 may not be etched or the etched area may be too small, which will increase the difficulty for the detection module 34 to detect the crack based on the location of the etched metal structure 130. If the second etching treatment time is too long, it will waste process time. Therefore, in this embodiment, the time for the second etching treatment is 5 to 10 minutes.

[0136] The detection module 34 detects the cracks based on the location of corrosion of the metal structure 130. It can not only detect minor cracks that have not completely penetrated the passivation layer 100, thus improving the accuracy and effectiveness of crack defect detection, but also identify cracks of different severity and with reliability risks by using different steps.

[0137] Furthermore, this embodiment performs a deterioration treatment, a first corrosion treatment, and a second corrosion treatment on the top passivation layer 120, so that when there is a crack defect in the passivation layer 100, the metal structure 130 below the crack defect can be corroded. This facilitates the location of the crack defect based on the location of the corrosion of the metal structure 130, which is beneficial for the rapid, efficient, and accurate detection of crack defects.

[0138] Specifically, cracks are usually quite small. Compared with direct observation of cracks, locating crack defects based on the location of corrosion of the metal structure 130 can magnify the defects at the crack location, making it easier to observe the location of corrosion of the metal structure 130 and thus facilitating the rapid and efficient location of crack defects.

[0139] In this embodiment, the detection module 34 uses an optical microscope to locate the location of corrosion on the metal structure 130. Specifically, the area of ​​corrosion on the metal structure 130 is usually large, thus enabling the location of corrosion on the metal structure 130 to be located using an optical microscope. The operation is simple and can be completed in a general chemical laboratory.

[0140] Reference Figure 9 This shows a top-view schematic diagram of the metal structure 130 under an optical microscope. Figure 9(a) shows a top view of the metal structure 130 before the deterioration treatment, the first corrosion treatment, and the second corrosion treatment. Figure 9 (b) shows a top view of the metal structure 130 after the deterioration treatment, the first corrosion treatment, and the second corrosion treatment.

[0141] like Figure 9 As shown, before the deterioration treatment, the first corrosion treatment, and the second corrosion treatment, the cracks were barely visible under an optical microscope. After the deterioration treatment, the first corrosion treatment, and the second corrosion treatment, the corroded location 200 of the metal structure 130 could be clearly and obviously observed under an optical microscope, thus facilitating the rapid and accurate location of the crack defects.

[0142] Accordingly, in specific implementations, after locating the corroded position of the metal structure 130 using an optical microscope, if necessary, an electron scanning microscope can also be used to observe the corroded position of the metal structure 130 to further observe the crack defects in the passivation layer 100 at that location.

[0143] It should be noted that, in this embodiment, the crack defect detection system 30 is used to detect crack defects after the passivation layer 100 is formed and before entering the packaging process, so that crack defects can be detected before packaging, which helps to reduce invalid packaging and subsequent reliability testing, and correspondingly helps to save costs.

[0144] In other embodiments, the crack defect detection system can also be used to detect crack defects during the unsealing analysis process.

[0145] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for detecting crack defects, characterized in that, This is used to detect crack defects in a passivation layer, which includes a bottom passivation layer covering the top surface and sidewalls of a metal structure and a top passivation layer located on the bottom passivation layer; the crack defects in the passivation layer include one or more of a first type of crack, a second type of crack, and a third type of crack, wherein the first type of crack penetrates a portion of the thickness of the top passivation layer, the second type of crack penetrates the top passivation layer and a portion of the thickness of the bottom passivation layer, and the third type of crack penetrates the top passivation layer and the bottom passivation layer; The method for detecting crack defects includes: The top passivation layer is subjected to a deterioration process to allow the first type of crack to penetrate the top passivation layer when there is a first type of crack in the passivation layer, thereby exposing the bottom passivation layer. A first corrosion treatment is performed to etch the bottom passivation layer exposed by the first and second type of cracks when the passivation layer has first and second type of cracks, so as to expose the metal structure. A second corrosion treatment is performed to corrode the metal structure exposed by the first, second, and third type of cracks when the passivation layer has first, second, and third type of cracks. The cracks are detected based on the location of corrosion on the metal structure.

2. The method for detecting crack defects as described in claim 1, characterized in that, The crack defect detection method is performed after the passivation layer is formed and before the encapsulation process.

3. The method for detecting crack defects as described in claim 1, characterized in that, The crack defect detection method is used during the unsealing analysis process.

4. The method for detecting crack defects as described in claim 1, characterized in that, The metal structure includes metal wires.

5. The method for detecting crack defects as described in claim 1, characterized in that, The material of the metal structure includes one or more of aluminum, copper, cobalt, tungsten, and nickel.

6. The method for detecting crack defects as described in claim 1, characterized in that, The steps for detecting cracks based on the location of corrosion on the metal structure include: after performing a second corrosion treatment, locating the location of corrosion on the metal structure using an optical microscope.

7. The method for detecting crack defects as described in claim 1, characterized in that, The deterioration treatment process includes heat treatment.

8. The method for detecting crack defects as described in claim 7, characterized in that, The heat treatment includes thermal cycling tests.

9. The method for detecting crack defects as described in claim 8, characterized in that, The parameters for the thermal cycling test include: a temperature range of -65°C to 150°C, and a cycle time of 15 to 60 minutes.

10. The method for detecting crack defects as described in claim 1, characterized in that, The first corrosion treatment includes: using a first corrosion solution to perform a first corrosion treatment on the bottom passivation layer exposed by the first type of crack and the second type of crack.

11. The method for detecting crack defects as described in claim 10, characterized in that, The bottom passivation layer is made of silicon oxide; the first etching solution is a mixed solution of acetic acid and ammonium fluoride.

12. The method for detecting crack defects as described in claim 1, 10, or 11, characterized in that, The first etching process takes 20 to 40 seconds.

13. The method for detecting crack defects as described in claim 1, characterized in that, The second corrosion treatment includes: using a second corrosion solution to perform a second corrosion treatment on the metal structure exposed by the first type of crack, the second type of crack, and the third type of crack.

14. The method for detecting crack defects as described in claim 13, characterized in that, The material of the metal structure includes aluminum; the second etching solution includes hydrochloric acid solution.

15. The method for detecting crack defects as described in claim 1, 13, or 14, characterized in that, The second etching process takes 5 to 10 minutes.

16. A crack defect detection system, characterized in that, This is used to detect crack defects in a passivation layer, which includes a bottom passivation layer covering the top surface and sidewalls of a metal structure and a top passivation layer located on the bottom passivation layer; the crack defects in the passivation layer include one or more of a first type of crack, a second type of crack, and a third type of crack, wherein the first type of crack penetrates a portion of the thickness of the top passivation layer, the second type of crack penetrates the top passivation layer and a portion of the thickness of the bottom passivation layer, and the third type of crack penetrates the top passivation layer and the bottom passivation layer; The crack defect detection system includes: A passivation layer deterioration module is used to deteriorate the top passivation layer, and is adapted to allow the first type of crack to penetrate the top passivation layer when there is a first type of crack in the top passivation layer, so as to expose the bottom passivation layer. A first corrosion module is used to perform a first corrosion treatment, adapted to corrode the bottom passivation layer exposed by the first and second type of cracks when the passivation layer has a first type of crack and a second type of crack, so as to expose the metal structure. The second corrosion module is used to perform a second corrosion treatment when there are first-type cracks, second-type cracks, and third-type cracks in the passivation layer, and is suitable for corroding the metal structure exposed by the first-type cracks, second-type cracks, and third-type cracks. The detection module is used to detect the cracks based on the location of corrosion on the metal structure.

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