Virtual inking method for wafers

Abstract

The application provides a wafer virtual ink marking method. First, whether the wafer needs virtual ink marking for wafer testing is judged based on the number and distribution mode of the defective dies of the wafer. If yes, the failure source of the wafer is analyzed. When the failure source of the wafer cannot be analyzed, virtual ink marking is performed on at least part of the dies around each defective die. When the failure source of the wafer is analyzed, the wafer is divided into sub-regions based on the failure source of the wafer, and virtual ink marking is performed on all the dies in at least part of the sub-regions based on the distribution mode of the defective dies. The application does not need manual participation, the rules of virtual ink marking are uniform, the difference and misoperation of manual operation are avoided, and the efficiency of virtual ink marking is improved.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing technology, and in particular to a virtual ink-printing method for wafers. Background Technology

[0002] The general integrated circuit manufacturing process can be divided into the wafer manufacturing stage, the chip testing stage, and the chip packaging stage. As electronic products now emphasize thinness and small size, current packaging technologies are gradually moving towards advanced packaging technologies such as flip-chip packaging and multi-chip modules in order to reduce packaging size and improve integrated circuit performance. However, these advanced packaging methods are expensive. Therefore, it is best to perform wafer testing (CP testing) on ​​the wafer before packaging to remove defective chips on the wafer before the subsequent packaging process, thus saving unnecessary packaging costs.

[0003] After wafer testing, virtual ink application is often performed to mark the locations of defective dies. However, to improve throughput, current wafer testing is usually done by sampling rather than full testing. Dies not tested are typically assumed to be acceptable. This approach only works when there are no clusters of defective dies. Once clusters of defective dies are present, the dies surrounding those clusters are highly likely to be defective as well. If these are assumed to be acceptable and sent directly for packaging, it leads to wasted packaging costs and reduced yield. Furthermore, for high-requirement products such as automotive and military-grade products, even if full wafer testing is performed, dies surrounding clusters of defective dies, even if they are found to be acceptable, cannot be sent for packaging as finished products. Therefore, additional virtual ink application is required after wafer testing.

[0004] However, currently, virtual inkjet printing after wafer testing can usually only be done manually, which is inaccurate, inefficient, and prone to errors. Summary of the Invention

[0005] The purpose of this invention is to provide a virtual ink-printing method for wafers to solve the problems of poor accuracy, low efficiency, and error susceptibility in existing manual virtual ink-printing methods.

[0006] To achieve the above objectives, the present invention provides a virtual inkjet printing method for wafers, comprising:

[0007] Perform wafer testing on the wafer, and determine whether the wafer needs to undergo virtual inkjet printing based on the number and distribution of defective dies.

[0008] When it is determined that the wafer requires virtual inkjet printing for wafer testing, the failure sources of the wafer are analyzed; and,

[0009] When the source of failure of the wafer cannot be analyzed, virtual ink is applied to at least some of the wafers around each defective wafer. When the source of failure of the wafer is analyzed, the wafer is divided into sub-regions based on the source of failure of the wafer, and virtual ink is applied to all wafers in at least some of the sub-regions based on the distribution of the defective wafers.

[0010] Optionally, the wafer includes a central region and an edge region surrounding the central region. The step of determining whether the wafer needs virtual ink removal based on the number and distribution of defective dies includes:

[0011] The grain yield of the central region and the edge region are obtained respectively, and it is determined whether the grain yield of the central region is less than a first threshold and whether the grain yield of the edge region is less than a second threshold.

[0012] When the grain yield of the central region is determined to be less than the first threshold and / or the grain yield of the edge region is determined to be less than the second threshold, it is determined whether the defective grains satisfy a predetermined clustering rule; and,

[0013] When the defective die is determined to meet the clustering rules, it is determined that the wafer needs to undergo virtual inkjet printing for wafer testing.

[0014] Optionally, the clustering rule includes that, among the defective grains exceeding a first predetermined number, the number of qualified grains between each pair of adjacent defective grains is less than a second predetermined number, wherein the pair of adjacent defective grains includes two adjacent defective grains in the lateral, longitudinal, and two diagonal directions.

[0015] Optionally, performing virtual inking on at least a portion of the grains surrounding each defective grain includes at least one of performing virtual inking on a third predetermined number of grains on both sides of the defective grain in the transverse direction, performing virtual inking on a fourth predetermined number of grains on both sides of the defective grain in the longitudinal direction, performing virtual inking on a fifth predetermined number of grains on both sides of the defective grain in the first diagonal direction, and performing virtual inking on a sixth predetermined number of grains on both sides of the defective grain in the second diagonal direction.

[0016] Optionally, the wafer may have several failure sources. The wafer may be divided into sub-regions based on different failure sources, and virtual ink-printing may be performed on each sub-region. All virtual ink-printing results may be superimposed.

[0017] Optionally, the failure source of the wafer includes at least one of the exposure machine, the clamping machine, and the grinding machine.

[0018] Optionally, when the failure source of the wafer is the exposure machine, the wafer is divided into several sub-regions corresponding to the exposure field of view of the exposure machine, and virtual ink is applied to all the wafers in the sub-region where the defective wafers satisfy the clustering rules are located.

[0019] Optionally, the clamping machine has several grippers. When the failure source of the wafer is the clamping machine, the wafer is divided into several concentric rings, and based on the number of grippers, the outermost ring is divided into several arc-shaped sub-regions. Virtual ink is applied to all the wafers in the sub-regions where the defective wafers satisfy the clustering rules are located.

[0020] Optionally, the grinding disc of the grinding machine has several concentric ring grinding areas, and the grinding pressure applied to each grinding area is independently controlled. When the failure source of the wafer is the grinding machine, the wafer is divided into several concentric rings based on the number of grinding areas, and each ring is divided into several arc-shaped sub-regions. Virtual ink is applied to all the grains in the sub-region where the defective grains satisfy the clustering rules are located.

[0021] Optionally, the virtual ink-printing method for the wafer further includes:

[0022] The wafer is subjected to defect testing, and based on the size and type of the defects on the wafer, it is determined whether the wafer needs to undergo virtual inkjet printing for the defect testing.

[0023] When it is determined that the wafer requires virtual inkjet printing for the defect test, virtual inkjet printing is performed on the grains covered by the defect; and...

[0024] After the virtual inkjet printing for the wafer test is completed, the virtual inkjet printing results for the wafer test are superimposed with the virtual inkjet printing results for the defect test.

[0025] Optionally, when the ratio of the maximum width of the defect on the wafer to the width of the grain is greater than a third threshold and / or the type of the defect belongs to a specific type, it is determined that the wafer needs to undergo virtual ink-printing for the defect test.

[0026] Optionally, the specific types include bridging defects and open circuit defects.

[0027] Optionally, when performing virtual ink printing, only qualified dies on the wafer are virtual ink printed, and each qualified die is virtual ink printed only once.

[0028] In the virtual ink-printing method for wafers provided by this invention, the method first determines whether the wafer needs virtual ink-printing for wafer testing based on the number and distribution of defective dies. If so, the failure source of the wafer is analyzed. If the failure source cannot be identified, virtual ink-printing is performed on at least a portion of the dies surrounding each defective die. If the failure source is identified, the wafer is divided into sub-regions based on the failure source, and virtual ink-printing is performed on all dies in at least a portion of the sub-regions based on the distribution of defective dies. This invention eliminates the need for manual intervention, standardizes virtual ink-printing rules, avoids differences and errors in manual operation, and improves the efficiency of virtual ink-printing. Attached Figure Description

[0029] Figure 1 A flowchart of a virtual ink-printing method for wafers provided in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the wafer testing results provided in this embodiment;

[0031] Figures 3a-3c A partial distribution diagram of the three types of defective grains provided in the embodiments of the present invention;

[0032] Figure 4a A schematic diagram of a defective grain provided in an embodiment of the present invention;

[0033] Figures 4b to 4g The embodiments of the present invention provide six different methods for using... Figure 4a A schematic diagram showing at least some of the grains around the defective grains in the image being virtually ink-stained;

[0034] Figure 5a and Figure 5b The embodiments of the present invention provide two different methods for using... Figure 3a A schematic diagram showing at least some of the grains surrounding all the aforementioned defective grains being virtually ink-stained;

[0035] Figure 6a This is a schematic diagram illustrating how the wafer is divided into several sub-regions corresponding to the exposure field of view of the exposure machine, as provided in an embodiment of the present invention.

[0036] Figure 6b The embodiments of the present invention provide a basis for... Figure 6a A schematic diagram of virtual ink application to all grains in the three sub-regions;

[0037] Figure 7a This is a schematic diagram illustrating how the wafer is divided into three concentric rings, and each ring is further divided into six sub-regions, according to an embodiment of the present invention.

[0038] Figure 7bThe embodiments of the present invention provide a basis for... Figure 7a A schematic diagram of virtual ink application to all grains in one sub-region;

[0039] Figure 8 The embodiments of the present invention provide a basis for... Figure 8 A schematic diagram of virtual ink application to all grains in the three sub-regions;

[0040] Figure 9 To be Figure 7b The virtual inkjet results and Figure 8 A schematic diagram showing the superimposed virtual ink printing results;

[0041] Figure 10 This is a schematic diagram illustrating other steps of the virtual inkjet printing method for wafers provided in an embodiment of the present invention. Detailed Implementation

[0042] The specific embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0043] Figure 1 This is a flowchart of the virtual ink-printing method for a wafer provided in this embodiment. Figure 1 As shown, the virtual ink-printing method for wafers provided in this embodiment includes steps S100, S200 and S300.

[0044] Execute step S100 to perform wafer testing on the wafer, and determine whether the wafer needs to undergo virtual inkjet printing for wafer testing based on the number and distribution of defective dies on the wafer.

[0045] Specifically, Figure 2 This is a schematic diagram of the wafer testing results provided in this embodiment, as shown below. Figure 2 As shown, wafer testing (CP testing) is performed on the wafer to identify bad dies on the wafer. Figure 2 The darker shaded areas) and qualified grains (Good Die, Figure 2 During wafer testing (in the area with lighter shades), the defective chips identified will be virtually marked, which is equivalent to marking the defective chips. Unmarked chips are all qualified chips.

[0046] Optionally, wafer testing can be performed on each die on the wafer to accurately identify defective and qualified dies. Alternatively, wafer testing can be performed on a sample of the dies on the wafer. Defective dies identified in the sampling test will be treated as defective dies and subjected to virtual ink printing, while qualified dies identified in the sampling test and dies that have not been tested will be treated as qualified dies.

[0047] It should be understood that performing wafer testing on the wafer may or may not involve actually performing the wafer testing. For example, at least one wafer may be randomly selected from a batch of wafers for testing, and the wafer testing results of the selected wafers may be superimposed to obtain the wafer testing results of the other wafers in the same batch. Alternatively, at least one batch of wafers may be randomly selected from multiple batches for testing, and the wafer testing results of the selected wafers may be superimposed to obtain the wafer testing results of the other batches in the multiple batches. Examples will not be provided here.

[0048] It is understood that the wafer includes a central region and an edge region surrounding the central region. Since the edge region is close to the edge of the wafer, the die yield of the edge region is usually lower, while the central region is located at the center of the wafer, so the die yield of the central region is usually higher.

[0049] In this embodiment, if the wafer yield is extremely high and the defective dies are dispersed, it generally indicates that the wafer manufacturing process is normal, and no additional virtual inkjet printing is needed after wafer testing. Conversely, additional virtual inkjet printing is required. In this embodiment, the determination of whether the wafer needs virtual inkjet printing (additional virtual inkjet printing) is based on the number and distribution of defective dies. Specifically, the die yield of the central region and the edge region are obtained separately, and it is determined whether the die yield of the central region is less than a first threshold and whether the die yield of the edge region is less than a second threshold. When it is determined that the die yield of the central region is less than the first threshold and / or the die yield of the edge region is less than the second threshold, it indicates that the die yield of the central region and / or the die yield of the edge region is too low. Next, it is determined whether the defective dies meet the predetermined clustering rules. When the defective dies meet the clustering rules, it indicates that the distribution of the defective dies is concentrated, and it is determined that the wafer needs to undergo virtual ink-printing for wafer testing. That is, when the die yield in the central region and / or the die yield in the edge region is too low, and the distribution of the defective dies is concentrated, the wafer needs to undergo virtual ink-printing for wafer testing. If the die yield in the central region and the die yield in the edge region are high, and the distribution of the defective dies is not concentrated, then virtual ink-printing for wafer testing is not required (the result of the wafer testing is taken as the standard), and the wafer can be released to proceed to the next process.

[0050] As an optional embodiment, the first threshold may be greater than the second threshold. For example, the first threshold may be greater than 90% and the second threshold may be greater than 70%, but should not be limited thereto.

[0051] Furthermore, in this embodiment, the clustering rule includes that among the defective grains exceeding a first predetermined number, the number of qualified grains between each pair of adjacent defective grains is less than a second predetermined number, wherein the two adjacent defective grains include two adjacent defective grains in the lateral direction, the longitudinal direction, and the two diagonal directions. Figures 3a-3c This embodiment provides a local distribution diagram of the three types of defective grains. For example, if the first predetermined number is 6 and the second predetermined number is 2, Figure 3a The sample contains 8 (more than 6) defective grains, and the number of acceptable grains between any two adjacent defective grains is 0 or 1 (both less than 2). Figure 3a The defective grains in the cluster satisfy the clustering rules; Figure 3b The sample contains 7 (more than 6) defective grains, and the number of acceptable grains between each pair of adjacent defective grains is 1 (less than 2). Figure 3b The defective grains in the cluster satisfy the clustering rules; Figure 3c The middle contains 4 (less than 6) of the aforementioned defective grains, therefore Figure 3b The defective grains in the cluster do not satisfy the clustering rules. For example, if the first predetermined quantity is 3 and the second predetermined quantity is 1, Figure 3a The sample contains 8 defective grains, of which 7 (more than 3) of the defective grains have 0 (less than 1) qualified grains between each pair of adjacent defective grains. Figure 3a The defective grains in the cluster satisfy the clustering rules; Figure 3b The sample contains 7 (more than 3) defective grains, and the number of acceptable grains between each pair of adjacent defective grains is 1 (equal to 1). Therefore... Figure 3b The defective grains in the cluster do not satisfy the clustering rules; Figure 3c The sample contains 4 (more than 3) defective grains, and the number of acceptable grains between any two adjacent defective grains is 0 (less than 1). Therefore... Figure 3c The defective grains in the cluster satisfy the clustering rules.

[0052] Step S200: When it is determined that the wafer needs to undergo virtual inkjet printing for wafer testing, analyze the source of the wafer failure.

[0053] Specifically, when the grain yield of the central region and / or the edge region of the wafer is high and defective grains that satisfy the clustering rules are generated, the failure of the wafer is usually not a random failure, but related to the specific process. For example, the source of the wafer failure may be at least one of the exposure machine, the clamping machine and the grinding machine.

[0054] Understandably, since the grippers of the clamping machine typically hold the wafer by contacting its edge region, failures caused by the clamping machine will result in defective grains concentrating in the edge region of the wafer and accumulating at the contact point of the grippers. Similarly, since the exposure machine exposes each exposure area on the wafer individually using a single exposure field, failures caused by the exposure machine will result in defective grains concentrating in one or more exposure areas. Likewise, the polishing machine's polishing disc has several concentric polishing areas, each with an independent polishing pressure. That is, when polishing the wafer, the polishing pressure applied to each polishing area is independently controlled. Therefore, failures caused by the polishing machine will result in defective grains concentrating in one or more annular areas of the wafer.

[0055] As can be seen, when the failure sources are different, the distribution locations of the defective grains that satisfy the clustering rules will also be different, which can be used to analyze the failure source of the wafer. Of course, the method of analyzing the failure source of the wafer is not limited to this, and it can also be combined with other methods for analysis.

[0056] It should be understood that even if the distribution location of the defective grains that satisfy the clustering rules is related to the source of failure, there are still cases where the source of failure of the wafer cannot be accurately analyzed.

[0057] In step S300, when the failure source of the wafer cannot be analyzed, virtual ink is applied to at least some of the wafers around each defective wafer. When the failure source of the wafer is analyzed, the wafer is divided into sub-regions based on the failure source, and virtual ink is applied to all wafers in at least some of the sub-regions based on the distribution of the defective wafers.

[0058] Specifically, if the source of failure of the wafer cannot be analyzed, when performing virtual ink removal on at least a portion of the grains surrounding each defective grain, at least one of the following can be performed: virtual ink removal on a third predetermined number of grains on both sides of the defective grain along the lateral direction; virtual ink removal on a fourth predetermined number of grains on both sides of the defective grain along the longitudinal direction; virtual ink removal on a fifth predetermined number of grains on both sides of the defective grain along the first diagonal direction; and virtual ink removal on a sixth predetermined number of grains on both sides of the defective grain along the second diagonal direction.

[0059] For example, Figure 4a This is a schematic diagram of a defective grain provided in this embodiment. Figure 4a In the diagram, the shaded areas represent the defective grains, while the other areas represent the qualified grains. Figures 4b to 4g This embodiment provides six different methods for using... Figure 4a A schematic diagram of virtual ink application to at least some of the grains surrounding defective grains. Figure 4b This demonstrates the case of virtually ink-spraying one grain on each side of the defective grain along the lateral direction. Figure 4c This demonstrates the case of virtually ink-spraying one grain on each side of the defective grain along the longitudinal direction. Figure 4d This demonstrates the case where virtual ink is applied to one grain on each side of the defective grain along the first diagonal direction (45° angle). Figure 4e This demonstrates the case where virtual ink is applied to one grain on each side of the defective grain along the second diagonal direction (-45° angle direction). Figure 4f This demonstrates the scenario where virtual ink is applied to one grain on each side of the defective grain simultaneously along the horizontal, vertical, first diagonal, and second diagonal directions. Figure 4g This demonstrates a scenario where virtual ink is applied to two grains on either side of the defective grain along the horizontal and vertical directions, and simultaneously, virtual ink is applied to one grain on either side of the defective grain along both the first and second diagonal directions. Of course, the scenario of virtually ink-applying at least some grains surrounding the defective grain is not limited to this. The specific values ​​of the third, fourth, fifth, and sixth predetermined quantities can be selected according to actual product needs, and virtual ink can also be applied to certain grains surrounding the defective grain, depending on the actual product requirements.

[0060] Figure 5a and Figure 5b This embodiment provides two different methods for... Figure 3a A schematic diagram of virtual ink application to at least some of the grains surrounding all the aforementioned defective grains. Figure 5a This demonstrates the scenario where virtual ink is applied to one grain on each side of all the aforementioned defective grains simultaneously along the horizontal, vertical, first diagonal, and second diagonal directions. Figure 5b This demonstrates the case of virtually ink-spraying two grains on either side of each of the aforementioned defective grains, applied longitudinally. Figure 5a and Figure 5b As can be seen, since the defective dies have been marked (virtual ink-printing) when the wafer is tested, when virtual ink-printing is performed on at least some dies around the defective die, only the qualified dies need to be virtual ink-printed, instead of repeating the virtual ink-printing on the defective die. Each qualified die is also virtual ink-printed only once, thereby avoiding the repeated virtual ink-printing on a die.

[0061] Furthermore, when the failure source of the wafer is analyzed, the wafer needs to be divided into sub-regions based on the failure source. Specifically, when the failure source of the wafer is the exposure equipment, the wafer is first divided into several sub-regions corresponding to the exposure field of view of the exposure equipment. Figure 6a This is a schematic diagram illustrating the division of the wafer into several sub-regions corresponding to the exposure field of view of the exposure machine, as provided in this embodiment. Figure 6a As shown, the sub-region corresponds one-to-one with the exposure field of view of the exposure machine. That is, the sub-region is the exposure area where the exposure machine exposes the wafer in one exposure process. It should be understood that the exposure field of view of the exposure machine is usually rectangular. However, when exposing the edge area of ​​the wafer, there will be an invalid area outside the wafer in the exposure field of view of the exposure machine. Therefore, the sub-region is not necessarily rectangular.

[0062] Next, based on the distribution pattern of the defective grains, virtual ink is applied to all grains in at least a portion of the sub-regions. Figure 6b The embodiment provided for Figure 6a A schematic diagram of virtual ink application to all grains in the three sub-regions, as shown below. Figure 6b As shown, in this embodiment, the defective grains that satisfy the clustering rules are located in three adjacent sub-regions. Therefore, virtual ink is applied to all grains in these three sub-regions, which is equivalent to marking all grains in these three sub-regions as defective grains.

[0063] Furthermore, when the failure source of the wafer is the clamping machine, the wafer is first divided into several concentric rings, and then the outermost ring is divided into several arc-shaped sub-regions based on the number of grippers. Figure 7a This embodiment provides a schematic diagram of dividing the wafer into three concentric rings, with each ring further divided into six sub-regions, as shown below. Figure 7a As shown, in this embodiment, the number of grippers is 3. For ease of operation, the wafer is directly divided into 6 fan-shaped regions along the radial direction. After the 6 fan-shaped regions are superimposed with the 3 concentric rings, each ring is divided into 6 arc-shaped sub-regions. Figure 7b The embodiment provided for Figure 7a A schematic diagram of virtual ink application to all grains in a sub-region, as shown below. Figure 7b As shown, in this embodiment, the defective grains that satisfy the clustering rules are located in a sub-region of the outermost ring. Therefore, all grains in this sub-region are virtually inkd (shaded area), which is equivalent to marking all grains in this sub-region as defective grains.

[0064] Furthermore, when the failure source of the wafer is the grinding machine, the wafer is divided into several concentric rings based on the number and size of the grinding areas, and each ring is further divided into several arc-shaped sub-regions. Please continue reading. Figure 7a In this embodiment, the number of grinding areas is also 3. For ease of operation, the wafer is directly divided into 6 fan-shaped areas along the radial direction. After the 6 fan-shaped areas are superimposed with the 3 concentric rings, each ring is divided into 6 arc-shaped sub-regions. Figure 8 The embodiment provided for Figure 8 A schematic diagram of virtual ink application to all grains in the three sub-regions, as shown below. Figure 8 As shown, in this embodiment, the defective grains that satisfy the clustering rules are located in three adjacent sub-regions of the middle ring. Therefore, all grains in these three sub-regions are virtually inkd (shaded), which is equivalent to marking all grains in these three sub-regions as defective grains.

[0065] In this embodiment, when the failure source of the wafer is the clamping machine and the grinding machine, the wafer is uniformly divided into 3 concentric rings, and each ring is uniformly divided into 6 arc-shaped sub-regions. However, this is not a limitation. The number of concentric rings and the number of arc-shaped sub-regions divided into the wafer by the two failure sources can be the same or different.

[0066] It is worth noting that when the wafer failure originates from the clamping machine, there is no requirement for the number of concentric rings divided into the wafer. However, the outermost ring needs to be divided into several arc-shaped sub-regions based on the number of grippers. Preferably, the contact position between each gripper and the wafer can be close to the axis of the corresponding sub-region, and the number of arc-shaped sub-regions divided into the outermost ring is twice the number of grippers. Furthermore, when the wafer failure originates from the grinding machine, there is no requirement for the number of arc-shaped sub-regions divided into each ring. However, the wafer needs to be divided into several concentric rings based on the number of grinding areas on the grinding wheel, and the number of grinding areas on the grinding wheel is equal to the number of concentric rings divided into the wafer.

[0067] Optionally, this embodiment is not limited to dividing the wafer into 3 concentric rings, but can also divide it into 2, 4 or 5 or more. Each ring is not limited to dividing into 6 arc-shaped sub-regions, but can also be divided into 2, 3, 4, 5 or 6 or more. These will not be explained in detail here.

[0068] Furthermore, when there are multiple sources of failure in the wafer, the wafer is divided into sub-regions based on different sources of failure and virtual ink is applied to each sub-region, and then all virtual ink application results are superimposed. Figure 9 To be Figure 7b The virtual inkjet results and Figure 8 A schematic diagram showing the superimposed virtual inkjet results, from Figure 9 As can be seen, after superimposing all the virtual ink-printing results, all the grains that underwent virtual ink-printing under different failure sources are regarded as defective grains.

[0069] It should be understood that since the defective grains have already undergone virtual ink-printing, when performing virtual ink-printing on all grains in the sub-region as a whole, only the qualified grains in the sub-region are virtual ink-printed, and it is not necessary to repeat the virtual ink-printing on the defective grains in the sub-region. Furthermore, each qualified grain is only virtual ink-printed once, thereby avoiding the repeated virtual ink-printing on a single grain.

[0070] Figure 10 This is a schematic diagram illustrating other steps of the virtual inkjet printing method for wafers provided in this embodiment. (See attached diagram.) Figure 10As shown, in this embodiment, the virtual ink-printing method for the wafer further includes steps S400, S500, and S600.

[0071] Step S400 is executed to perform defect testing on the wafer, and to determine whether the wafer needs to undergo virtual inkjet printing for the defect test based on the size and type of the defects on the wafer.

[0072] Specifically, after performing defect testing on the wafer, the size and type of defects on the wafer can be obtained. It should be understood that if the size of the defects on the wafer is large or the type of defects on the wafer belongs to a specific type, additional virtual inkjet printing is also required, i.e., virtual inkjet printing for the defect testing.

[0073] Furthermore, when the ratio of the maximum width of the defect on the wafer to the width of the grain is greater than a third threshold and / or the type of the defect belongs to a specific type, it is determined that the wafer needs to undergo virtual inkjet printing for the defect test.

[0074] Optionally, the third threshold can be designed according to the actual product requirements, and the specific type can be bridging defects and open circuit defects, etc., which will not be explained in detail here.

[0075] In step S500, when it is determined that the wafer needs to undergo virtual ink-printing for the defect test, virtual ink-printing is performed on the grains covered by the defect.

[0076] Specifically, when it is determined that the wafer needs to undergo virtual ink-printing for the defect test, even if the die covered by the defect is a qualified die, it still needs to undergo virtual ink-printing and be marked as a defective die, so as to meet the high requirements of the product.

[0077] As an optional embodiment, steps S400 and S500 can be performed before step S100, after step S300, or simultaneously with steps S100 to S300. The present invention does not impose any restrictions.

[0078] In step S600, after the virtual ink application for the wafer test is completed, the virtual ink application result for the wafer test is superimposed with the virtual ink application result for the defect test.

[0079] Specifically, when virtual inkjet printing is required for wafer testing and defect testing, after virtual inkjet printing is performed for wafer testing and defect testing respectively, the virtual inkjet printing results for wafer testing and the virtual inkjet printing results for defect testing are superimposed to meet the high requirements of the product.

[0080] Optionally, the virtual ink-printing results for the wafer test and the virtual ink-printing results for the defect test can be superimposed to send a warning message to the user.

[0081] It should be understood that "virtual ink printing" in this article does not refer to printing actual ink dots on the die, but rather to recording the position of the die. The virtual ink printing result includes the position of all the dies that have been "virtually ink printed", which is equivalent to marking the defective dies on the wafer.

[0082] In summary, the virtual ink-printing method for wafers provided in this invention first determines whether virtual ink-printing for wafer testing is required based on the number and distribution of defective dies. If so, the failure source of the wafer is analyzed. If the failure source cannot be identified, virtual ink-printing is performed on at least a portion of the dies surrounding each defective die. If the failure source is identified, the wafer is divided into sub-regions based on the failure source, and virtual ink-printing is performed on all dies in at least a portion of the sub-regions based on the distribution of defective dies. This invention eliminates the need for manual intervention, standardizes virtual ink-printing rules, avoids differences and errors in manual operation, and improves the efficiency of virtual ink-printing.

[0083] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0084] It should also be noted that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. 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 present invention shall still fall within the scope of protection of the present invention.

[0085] It should also be understood that, unless otherwise specified or indicated, the terms “first,” “second,” “third,” etc., in the specification are used only to distinguish the various components, elements, and steps in the specification, and not to indicate the logical or sequential relationships between the various components, elements, and steps.

[0086] Furthermore, it should be recognized that the terminology described herein is used only to describe particular embodiments and not to limit the scope of the invention. It must be noted that the singular forms “a” and “an” used herein and in the appended claims include plural bases unless the context clearly indicates otherwise. For example, a reference to “a step” or “an apparatus” means a reference to one or more steps or apparatuses, and may include secondary steps and secondary apparatuses. All conjunctions used should be understood in the broadest sense. Also, the word “or” should be understood to have the definition of logical “or” rather than logical “exclusive OR”, unless the context clearly indicates otherwise. Furthermore, implementation of the methods and / or devices in embodiments of the invention may include performing selected tasks manually, automatically, or in combination.

Claims

1. A virtual inkjet printing method for wafers, characterized in that, include: Perform wafer testing on the wafer, and determine whether the wafer needs to undergo virtual inkjet printing based on the number and distribution of defective dies. When it is determined that the wafer requires virtual inkjet printing for wafer testing, the failure sources of the wafer are analyzed; and, When the failure source of the wafer cannot be analyzed, virtual ink is applied to at least some of the wafers around each defective wafer. When the failure source of the wafer is analyzed, the wafer is divided into sub-regions based on the failure source of the wafer, and virtual ink is applied to all wafers in at least some of the sub-regions based on the distribution pattern of the defective wafers. The wafer includes a central region and an edge region surrounding the central region. The step of determining whether the wafer needs virtual ink removal based on the number and distribution of defective dies includes: The grain yield of the central region and the edge region are obtained respectively, and it is determined whether the grain yield of the central region is less than a first threshold and whether the grain yield of the edge region is less than a second threshold. When the grain yield of the central region is determined to be less than the first threshold and / or the grain yield of the edge region is determined to be less than the second threshold, it is determined whether the defective grains satisfy a predetermined clustering rule; and, When the defective die is determined to meet the clustering rules, it is determined that the wafer needs to undergo virtual inkjet printing for wafer testing.

2. The virtual ink-printing method for wafers as described in claim 1, characterized in that, The clustering rule includes that, among the defective grains exceeding a first predetermined number, the number of qualified grains between each pair of adjacent defective grains is less than a second predetermined number, wherein the two adjacent defective grains include two adjacent defective grains in the lateral, longitudinal, and two diagonal directions.

3. The virtual ink-printing method for wafers as described in claim 1, characterized in that, Virtual ink application to at least a portion of the grains surrounding each defective grain includes at least one of the following: virtual ink application to a third predetermined number of grains on both sides of the defective grain along the transverse direction; virtual ink application to a fourth predetermined number of grains on both sides of the defective grain along the longitudinal direction; virtual ink application to a fifth predetermined number of grains on both sides of the defective grain along the first diagonal direction; and virtual ink application to a sixth predetermined number of grains on both sides of the defective grain along the second diagonal direction.

4. The virtual ink-printing method for wafers as described in claim 1, characterized in that, The wafer has several failure sources. Based on different failure sources, the wafer is divided into sub-regions and virtual ink is applied to each sub-region. All virtual ink application results are then superimposed.

5. The virtual ink-printing method for wafers as described in claim 4, characterized in that, The failure sources of the wafer include at least one of the exposure equipment, clamping equipment, and grinding equipment.

6. The virtual ink-printing method for wafers as described in claim 5, characterized in that, When the failure source of the wafer is the exposure machine, the wafer is divided into several sub-regions corresponding to the exposure field of view of the exposure machine, and virtual ink is applied to all the wafers in the sub-region where the defective wafers satisfy the clustering rules are located.

7. The virtual ink-printing method for wafers as described in claim 5, characterized in that, The clamping machine has several grippers. When the failure source of the wafer is the clamping machine, the wafer is divided into several concentric rings, and based on the number of grippers, the outermost ring is divided into several arc-shaped sub-regions. Virtual ink is applied to all the wafers in the sub-regions where the defective wafers satisfy the clustering rules are located.

8. The virtual ink-printing method for wafers as described in claim 5, characterized in that, The grinding wheel of the grinding machine has several concentric ring grinding areas. The grinding pressure applied to each grinding area is independently controlled. When the failure source of the wafer is the grinding machine, the wafer is divided into several concentric rings based on the number of grinding areas, and each ring is divided into several arc-shaped sub-regions. Virtual ink is applied to all the grains in the sub-region where the defective grains satisfy the clustering rules are located.

9. The virtual ink-printing method for wafers as described in claim 1, characterized in that, The virtual ink-printing method for the wafer also includes: The wafer is subjected to defect testing, and based on the size and type of the defects on the wafer, it is determined whether the wafer needs to undergo virtual inkjet printing for the defect testing. When it is determined that the wafer requires virtual inkjet printing for the defect test, virtual inkjet printing is performed on the grains covered by the defect; and... After the virtual inkjet printing for the wafer test is completed, the virtual inkjet printing results for the wafer test are superimposed with the virtual inkjet printing results for the defect test.

10. The virtual ink-printing method for wafers as described in claim 9, characterized in that, When the ratio of the maximum width of the defect on the wafer to the width of the die is greater than a third threshold and / or the type of the defect belongs to a specific type, it is determined that the wafer needs to undergo virtual ink-printing for testing the defect; the specific type includes bridging defects and open circuit defects.

11. The virtual ink-printing method for a wafer as described in any one of claims 1-10, characterized in that, During virtual ink printing, only qualified dies on the wafer are virtual ink printed, and each qualified die is virtual ink printed only once.

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