CN112988792B

CN112988792B - Searching method and device for wafer yield problem database

Info

Publication number: CN112988792B
Application number: CN202110407543.5A
Authority: CN
Inventors: 徐文丞; 易丛文; 林孟喆; 戴静安
Original assignee: Raft Ferry Shanghai Technology Co ltd
Current assignee: Shenzhen Zhixian Future Industrial Software Co ltd
Priority date: 2021-04-15
Filing date: 2021-04-15
Publication date: 2022-05-31
Anticipated expiration: 2041-04-15
Also published as: CN112988792A

Abstract

The embodiment of the invention provides a method and a device for searching a wafer yield problem database, wherein the wafer yield problem database is pre-established and comprises a plurality of failure categories, relevant failure characteristics and corresponding evidentiary data, and the method comprises the following steps: determining a number of second wafer maps having a predetermined failure mode among the plurality of first wafer maps; extracting a first failure feature of the second wafer map to determine a first failure category of the second wafer map; determining a plurality of second failure categories in the plurality of failure categories and the matching number of the failure characteristics of the first failure category and the second failure categories according to the similarity of the failure characteristics of the first failure category and the plurality of failure categories; determining the matching number of the evidentiary data of the first failure category and each second failure category according to the similarity of the evidentiary data of the first failure category and the second failure category; and according to the failure characteristics and the matching number of the evidentiary data, carrying out first sequencing on a plurality of second failure categories and displaying the second failure categories.

Description

Searching method and device for wafer yield problem database

Technical Field

The invention relates to the field of chip manufacturing, in particular to a method and a device for searching a wafer yield problem database.

Background

During the semiconductor chip manufacturing process, wafer products having yield failures may be generated below a reference yield due to various unexpected (excessive) reasons from a normal process. Usually, yield engineers conduct analysis and investigation according to the failure characteristics of the faulty wafer, and find the cause of the problem and repair and solve the problem as soon as possible. Speed is extremely important in the process, and the problem can be found and solved one hour earlier, so that the problem of the yield of products passing through the production line within one hour can be solved. When finding a wafer with a yield failure, yield engineers usually analyze and check related data based on past experience and conjecture, and expect to find the cause of the problem in the shortest time. The experience of the yield engineer is usually limited to the recent yield failure problem experienced by an individual and cannot systematically cover all the problems occurring in the whole production line, so that the efficiency of searching and matching is not high, the problems are easily missed, the time is delayed, and the loss is caused.

Disclosure of Invention

The embodiment of the invention provides a method and a device for searching a wafer yield problem database. According to the method, for a wafer graph to be checked with a preset failure mode, failure features are extracted to obtain failure categories to be determined, then relevant failure features of the failure categories to be determined are matched with failure features relevant to all known failure categories in a wafer yield problem database established in advance, indicative data of the failure categories to be determined are matched with the indicative data of the known failure problems in the wafer yield problem database, and a sorted list of the known yield failure categories possibly matched with the failure categories to be determined is obtained from the database by combining the two matching results. By using the method, the efficiency and the capability of tracing the yield problem can be greatly improved.

The invention adopts a technical scheme for solving the technical problems, and provides a method for searching a wafer yield problem database, wherein the wafer yield problem database is established in advance and comprises a plurality of failure categories, failure characteristics related to the failure categories and corresponding evidentiary data, and the method comprises the following steps:

determining, among the plurality of first wafer maps, a number of second wafer maps in which a predetermined failure mode exists;

extracting a plurality of first failure characteristics in the plurality of second wafer maps;

determining a first failure category of each second wafer map according to the first failure characteristics;

determining a plurality of second failure categories in the plurality of failure categories and the matching number of the first failure category and the failure characteristics of each second failure category according to the similarity between the first failure characteristics related to the first failure category and the failure characteristics related to the plurality of failure categories;

obtaining evidentiary data corresponding to the first failure category;

determining the matching number of the first failure category and the evidentiary data of each second failure category according to the similarity of the evidentiary data corresponding to the first failure category and the evidentiary data corresponding to each second failure category;

performing first sequencing on the plurality of second failure categories according to the failure feature matching number and the evidentiary data matching number;

and displaying the plurality of second failure categories according to the result of the first sorting.

Preferably, the first ranking of the plurality of second failure categories according to the failure feature matching number and the evidentiary data matching number includes:

and performing first sequencing on the plurality of second failure categories according to the weighted sum of the failure feature matching number and the evidentiary data matching number.

Specifically, the weighted sum of the failure feature matching number and the evidentiary data matching number is obtained, and the weighted value of the evidentiary data matching number is higher than the failure feature matching number.

Preferably, the failure characteristics comprise one or more of a failure function composition characteristic, a failure pattern shape characteristic, a failure position characteristic and a failure pattern occurrence frequency characteristic.

Preferably, determining, according to similarity between a first failure feature related to the first failure category and failure features related to the multiple failure categories, a number of second failure categories in the multiple failure categories and a number of failure features of the first failure category and each of the second failure categories respectively matching the first failure category, includes:

determining a plurality of third failure categories in the plurality of failure categories and the matching number of the first failure category and the failure characteristics of each third failure category according to the similarity between the first failure characteristics related to the first failure category and the failure characteristics related to the plurality of failure categories;

performing second sorting on a plurality of third failure categories according to the failure feature matching number;

and taking a predetermined number of the third failure categories before the second sorted order as second failure categories.

In particular, the method further comprises,

and displaying the plurality of third failure categories according to the result of the second sorting.

Preferably, the plurality of second failure categories are presented as a result of the first ranking, including,

displaying the plurality of second failure categories and corresponding indicative data thereof according to the result of the first sorting,

and/or

And displaying the manual remark information corresponding to the plurality of second failure categories.

Preferably, the method further comprises the step of,

performing third sorting on the plurality of second failure categories according to the matching quantity of the evidentiary data;

and displaying the plurality of second failure categories according to the result of the third sorting.

Preferably, the method further comprises the step of,

and determining whether to add the first failure category as a new failure category to the wafer yield problem database according to the failure feature matching number and the evidentiary data matching number.

In a second aspect, an apparatus for searching a wafer yield problem database is provided, the wafer yield problem database being pre-established and including a plurality of failure categories, and failure characteristics and corresponding indicative data associated with the plurality of failure categories, the apparatus comprising:

a failure mode searching unit configured to determine, among the plurality of first wafer maps, a number of second wafer maps in which a predetermined failure mode exists;

a failure feature determination unit configured to extract a plurality of first failure features in the plurality of second wafer maps;

a first failure category determination unit configured to determine a first failure category of each second wafer map according to the first failure feature;

a failure feature matching number determination unit configured to determine, according to similarity between a first failure feature related to the first failure category and failure features related to the multiple failure categories, a number of second failure categories in the multiple failure categories and a number of failure feature matching numbers between the first failure category and each of the second failure categories;

the evidentiary data acquisition unit is configured to acquire the evidentiary data corresponding to the first failure category;

the verification data matching quantity determining unit is configured to determine the matching quantity of the first failure category and the verification data of each second failure category according to the similarity between the verification data corresponding to the first failure category and the verification data corresponding to each second failure category;

the sorting unit is configured to perform first sorting on the plurality of second failure categories according to the failure feature matching quantity and the evidentiary data matching quantity;

and the result display unit is configured to display the plurality of second failure categories according to the first sorted result.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of a method for searching a wafer yield problem database according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a wafer according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of wafer map classification results according to an embodiment of the present invention

FIG. 4 is a block diagram of a searching apparatus for a wafer yield problem database according to an embodiment of the present invention;

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

As mentioned above, in the conventional wafer products with yield failures, a yield engineer is usually relied on to analyze and investigate the failure characteristics of the failed wafers based on past experience, so as to find the cause of the problem. On one hand, such an analysis process is usually time-consuming, and it is very important for the chip production line to shorten the resolution time of the yield problem; on the other hand, the experience of the yield engineers is often limited to recently occurring yield failure problems experienced by individuals, and it is difficult to systematically cover various problems occurring over a long period of time throughout the production line, thereby affecting the ability of the yield engineers to discover problems.

In order to solve the above technical problems, the inventor proposes a method for searching a wafer yield problem database in this specification, which determines a wafer map of a specific failure mode from a wafer map to be checked, extracts failure features from the wafer map, classifies yield problems according to the failure features to obtain yield problems to be determined, and then determines a yield problem list possibly corresponding to the yield problems to be determined according to the failure features and indicative data of the yield problems to be determined and a weighting result of matching degrees of the failure features and indicative data of known yield problems in a pre-established yield problem database, or adds the yield problems to be determined as new yield problems to the yield problem database. By using the method, on one hand, the time for determining the yield problem can be greatly reduced, and on the other hand, the capability of determining the yield problem with longer time span and wider coverage area is improved.

Fig. 1 is a flowchart of a method for searching a wafer yield problem database according to an embodiment of the present invention. The wafer yield problem database is pre-established, and includes a plurality of failure categories, failure characteristics related to the failure categories, and corresponding indicative data, as shown in fig. 1, the process of the method at least includes:

and step 11, determining a plurality of second wafer maps with preset failure modes in the plurality of first wafer maps.

The wafer map (wafer map) can be obtained according to the test result of the wafer function test. Generally, the wafer map shows the failure function and location of a failed die in the wafer. In one example, the disablement function also has a corresponding disablement function number. In general, in the semiconductor integrated circuit manufacturing process, high purity silicon is generally made into cylindrical rods (e.g., 6 inches, 8 inches or 12 inches in diameter), and the integrated circuit manufacturing enterprises laser cut these rods into very thin silicon wafer circles, and then use optical and chemical etching methods to form circuits and electronic components thereon, so that each silicon wafer after being manufactured has a large number of semiconductor chips, and these processed circular silicon wafers are wafer wafers. Functional testing is performed on a wafer, which is to perform functional (mainly electrical) testing on all chips (or dies) in the wafer. In different embodiments, a number of different functional tests may be performed, for example, one functional test may be to test whether a pad/pad or pin/pin is shorted, and to test whether a short is in the protection diode circuit. The test method may be to apply a current to the circuit and measure the voltage, if the voltage is too low, indicating a short circuit. Another functional test may be to test the I/O pin and open circuit of the protection diode circuit. The test method may be to apply a current to the circuit and measure the voltage, and if the voltage is too high, it indicates an open circuit. The specification is not limited to what kind of functional test is specifically adopted and the specific test mode thereof.

Fig. 2 shows a schematic view of a wafer provided by an embodiment of the present invention. As can be seen from the foregoing, semiconductor chips are produced by forming circuits on a wafer by various complex physicochemical processes. Usually, different electrical function tests are performed at the final stage of production to ensure the functionality of the product, and the pattern generated by combining the test results with the shape of the Wafer is the Wafer Map (Wafer Map). In the wafer map, the test completion result can be indicated on the position of each die by different colors, shapes or codes in units of die (chips not packaged). Therefore, the wafer map provides an important clue for tracing the cause of the abnormal product, and the spatial distribution of the wafer map and the model analysis thereof can be used to find out the cause of the low yield (such as the problem production equipment or the abnormal process step). The specific manner in which the wafer map is generated is not limited in this specification as long as the failure function and location of each failed die is shown therein. Failed die in the wafer map, i.e., die that failed the functional test therein. Typically, a failed die will only be labeled with one failure function, which in different examples may be, for example, the primary failure function or, for example, the failure function that first occurred during functional testing. The disabling function may also be of many specific types in different embodiments. For example, in one embodiment, the failure function may include a high frequency failure, a short circuit failure, an I/O pin open circuit failure, or a protection diode circuit open circuit failure. Each disabling function also has its own number. For example, in one example, the high frequency failure may be numbered as Bin2, the short circuit failure may be numbered as Bin3, and the I/O pin open failure or protection diode circuit open failure may be numbered as Bin 4. It is understood that different embodiments may have different failure function types and different failure function numbering manners, and the specific types and numbering manners of the failure functions are not limited in this specification.

In different embodiments, different specific failure modes, and different specific ways of determining failure modes, may be employed. Thus, in one embodiment, the failure mode may include a large area and/or continuous adjacent die functional failure. In a specific embodiment, it may be determined whether a plurality of wafer maps include a plurality of second wafer maps having a large area and/or a function failure of a consecutive adjacent die based on a preset rule according to a failure function and a location of a failed die included in each of the plurality of wafer maps. In another specific embodiment, a clustering operation may be further performed according to the failure functions and positions of failed dies included in each of the plurality of wafer maps, and it is determined whether a plurality of second wafer maps are included in the plurality of wafer maps according to the result of the clustering operation, where a large area and/or consecutive adjacent die function failures exist in the second wafer maps. For example, in one example, clustering may be performed based on a DBSCAN clustering algorithm to determine whether clusters including multiple failed dies can be obtained from a wafer map, thereby determining whether there is a large area and/or consecutive adjacent die functional failures in the wafer map.

In another embodiment, the failure mode may further include one or more of a failure rate of at least one function exceeding a reference failure rate and an overall wafer yield being lower than a reference yield, and in this embodiment, it may be determined whether a plurality of second wafer maps are included in the plurality of wafer maps based on at least a pre-obtained reference failure rate of each failure function, and a failure rate of at least one function in the second wafer maps exceeding the reference failure rate; and/or

Determining whether a plurality of second wafer maps are included in the plurality of wafer maps at least based on a pre-acquired wafer overall reference yield, wherein the overall yield of the second wafer maps is lower than the wafer overall reference yield.

In yet another embodiment, the failure mode may include the cumulative failure rate of the single-site die exceeding the site cumulative benchmark yield,

determining, among the plurality of first wafer maps, a number of second wafer maps in which a failure mode exists, comprising:

and determining whether the plurality of wafer maps comprise a plurality of second wafer maps or not at least based on the position accumulated reference yield acquired in advance, wherein the accumulated failure rate of a single-position tube core in the second wafer maps exceeds the position accumulated reference yield.

And 12, extracting a plurality of first failure characteristics in a plurality of second wafer maps.

In this step, the failure feature, i.e., the first failure feature, is extracted from the second wafer map obtained in step 11. In different embodiments, different specific failure characteristics may be extracted. In different embodiments, different failure characteristics may be provided.

In one embodiment, the failure characteristics in the second wafer map may be determined based on the failure function and location of each failed die in the wafer map where the failure mode exists.

In various embodiments, different failure characteristics may also be extracted based on the different aforementioned failure modes present in the second wafer map, for example, when a large area and/or consecutive adjacent die failures are present in the second wafer map, the extracted failure characteristics may include one or more of a component characteristic of the failure function, a failure pattern shape characteristic, a failure location characteristic, and a failure pattern occurrence frequency characteristic.

The specification does not limit the specific type and extraction manner of the failure feature.

And step 13, determining a first failure type of each second wafer map according to the failure characteristics.

In this step, according to the failure features of the second wafer maps extracted in step 12, failure classification is performed on the second wafer maps, that is, the first failure category is determined. The inventor finds that the closer the failure characteristics are to the wafer map, the greater the probability that the same reason or the like causes the failure is. Therefore, according to one embodiment, the failure characteristics of each second wafer map may be clustered, and the failure category of the second wafer map may be determined according to the obtained clustering result. For example, in one example, after the clustering operation, the plurality of second wafer maps are respectively placed in a plurality of clusters, and the failure features of the second wafer maps in the same cluster are close to each other in the feature space, so that it can be determined whether the second wafer maps belong to the same failure category at least according to whether the second wafer maps belong to the same cluster. Because the cluster result of the clustering operation is often influenced by parameter setting in different clustering algorithms, for example, the number of clusters obtained in the k-means clustering algorithm is determined by k parameters. Therefore, in different examples, the number of the clusters obtained may be adjusted by adjusting the parameter of the clustering operation. In addition, the obtained clusters can be screened according to a preset screening rule, and then the failure category can be determined according to the screened result.

In different embodiments, the clustering operations may be based on different clustering algorithms. For example, in one embodiment, the clustering algorithm may be a k-means clustering algorithm. In another embodiment, it may also be one of a BIRCH algorithm, a cancel algorithm.

Fig. 3 is a schematic diagram illustrating a wafer map classification result according to an embodiment of the invention. As shown in fig. 3, the wafer map surrounded by the boxes with different gray levels respectively belong to different failure categories.

Thus, the failure categories obtained in this step mean that they indicate different yield problems, so that the subsequent steps can be matched with known yield problems stored in the wafer yield database established in advance according to the failure categories.

And step 14, determining a plurality of second failure categories in the plurality of failure categories and the matching number of the first failure category and the failure characteristics of each second failure category according to the similarity between the first failure characteristics related to the first failure category and the failure characteristics related to the plurality of failure categories.

As mentioned above, the wafer yield problem database is pre-established, and includes a plurality of failure categories, which represent known yield problems, and the wafer yield problem database can also store failure characteristics related to the known failure categories. In this step, the first failure features associated with the first failure category are matched with the failure features of known failure categories in the wafer yield problem database according to similarity. In one example, whether the similarity reaches a predetermined threshold may be used as a condition whether to determine a feature match.

Then, a second failure category of the plurality of known failure categories can be determined according to the matching condition of the failure characteristics of the plurality of known failure categories and the first failure category. For example, according to one embodiment, a determination of whether each known failure category is a second failure category may be made based on whether the known failure category has a failure characteristic that matches that of the first failure category.

According to another embodiment, a portion of the known failure categories having failure characteristics matching those of the first failure category may be determined as the second failure category according to a predetermined rule. Therefore, in one embodiment, the number of the plurality of third failure categories in the plurality of failure categories and the number of the first failure category respectively matched with the failure features of the respective third failure categories may be determined according to the similarity between the first failure feature related to the first failure category and the failure features related to the plurality of failure categories;

In one embodiment, the plurality of third failure categories may also be presented in a second ranked result.

And step 15, obtaining evidentiary data corresponding to the first failure category.

In this step, forensic data corresponding to the first failure category and associated with the failure may be obtained from the production equipment monitoring system. In different embodiments, there may be different specific forensic data. In one example, the indicative data includes one or more of a correlation other test data/correlation other test data link, a process tool detected data anomaly alarm/process tool detected data anomaly alarm link.

And step 16, determining the matching number of the first failure category and the evidentiary data of each second failure category according to the similarity of the evidentiary data corresponding to the first failure category and the evidentiary data corresponding to each second failure category.

The wafer yield problem database may also store forensic data corresponding to known failure categories. Therefore, in this step, according to the similarity between the forensic data corresponding to the second failure category in the yield problem database and the forensic data corresponding to the first failure category, it may be determined how much forensic data is matched between each second failure category and the first failure category, that is, the number of forensic data matched between each second failure category and the first failure category is determined. In different embodiments, according to different specific evidentiary data, different specific ways of determining whether the evidentiary data is matched or not may be used. The specification does not limit the specific manner of determining whether the evidentiary data matches or not.

According to various embodiments, the second failure category may also be ranked and presented according to the number of evidentiary data matches. Therefore, in one embodiment, the plurality of second failure categories may be further sorted according to the matching number of the evidentiary data; and displaying the plurality of second failure categories according to the result of the third sorting.

And step 17, performing first sequencing on the plurality of second failure categories according to the failure feature matching number and the evidentiary data matching number.

In this step, the second failure category is sorted according to the failure feature matching number and the evidentiary data matching number. Different specific ordering may be possible according to different embodiments.

For example, in one embodiment, the number of second failure categories may be first ordered according to a weighted sum of the number of failed feature matches and the number of forensic data matches. In another embodiment, the weighted sum of the number of failed feature matches and the number of forensic data matches is higher for the number of forensic data matches than for the number of failed feature matches.

And step 18, displaying a plurality of second failure categories according to the result of the first sorting.

In this step, the second failure category is displayed according to the sequence obtained after the sorting in step 17, which means that a yield problem list possibly corresponding to the yield problem to be determined is displayed, and the list is an ordered list sorted according to the degree of correspondence, and the speed of determining the yield problem can be greatly increased by using the list. According to various embodiments, data associated with the second failure category may also be presented along with the second failure category. Therefore, in one embodiment, the plurality of second failure categories and their corresponding indicative data and/or manual remark information corresponding to the plurality of second failure categories may be displayed according to the result of the first sorting. In some production scenarios, the investigators with known yield problems manually annotate failure-related information found in the investigation process into the implementation system, and the failure-related information of the manual annotation is the manual annotation information. Thus, in one example, the manual remark information may include one or more of whether it is in a machine maintenance cycle, whether it is affected by an online experiment, or not. In another embodiment, one or more of a number of second failure category related failure characteristics and investigative conclusions may also be presented.

In practice, a known failure category matching the first failure category may not be stored in the existing database, that is, no yield problem corresponding to the yield problem to be determined (the yield problem represented by the first failure category) is collected in the existing database. If it can be determined that a known failure category which can be matched with the first failure category is not stored in the existing database according to the failure characteristics and the indicative data, the first failure category can be further stored into the yield problem database as a new yield problem. Therefore, in one embodiment, it may also be determined whether to add the first failure category as a new failure category to the wafer yield problem database according to the failure feature matching number and the evidentiary data matching number.

By using the searching method provided by the embodiment of the specification, after the yield problem to be determined occurs, according to the failure characteristics and the evidentiary data, the known yield problems are quickly searched and matched, the list of the known yield problems which are most likely to be matched with the yield problem to be determined and the failure related information of each known yield problem in the list are given, or the known yield problems are quickly deduced to be unknown yield problems, so that the speed of determining the yield problems is greatly increased, and the capability of finding the yield problems with longer time span and wider coverage is improved.

According to another embodiment, a searching apparatus for a wafer yield problem database is provided, and fig. 4 shows a structure diagram of the searching apparatus for the wafer yield problem database according to the embodiment of the present invention. The wafer yield problem database is pre-established and includes a plurality of failure categories, and failure characteristics and corresponding evidentiary data associated with the failure categories, as shown in fig. 4, the apparatus 400 includes:

a failure mode search unit 41 configured to determine, among the plurality of first wafer maps, a number of second wafer maps in which a predetermined failure mode exists;

a failure feature extraction unit 42 configured to extract a plurality of first failure features in the plurality of second wafer maps;

a first failure type determination unit 43 configured to determine a first failure type of each second wafer map according to the first failure feature;

a failure feature matching number determination unit 44 configured to determine, according to similarities between first failure features related to the first failure category and failure features related to the multiple failure categories, a number of second failure categories in the multiple failure categories and a number of failure feature matching numbers of the first failure category and each of the second failure categories, respectively;

a forensic data obtaining unit 45 configured to obtain forensic data corresponding to the first failure category;

a matching number determining unit 46 for the forensic data, configured to determine the matching number of the forensic data of the first failure category and the forensic data of each second failure category according to the similarity between the forensic data corresponding to the first failure category and the forensic data corresponding to each second failure category;

a sorting unit 47 configured to perform a first sorting on the plurality of second failure categories according to the failure feature matching number and the evidentiary data matching number;

and the result display unit 48 is configured to display the plurality of second failure categories according to the results of the first sorting.

According to an embodiment of yet another aspect, there is also provided a computer readable medium comprising a computer program stored thereon, which computer when executed performs the method described above.

According to an embodiment of a further aspect, there is also provided a computing device, including a memory and a processor, wherein the memory stores executable code, and the processor executes the executable code to implement the method described above.

The foregoing description has been directed to specific embodiments of this disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.

Those of skill would further appreciate that the various illustrative components and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied in hardware, a software module executed by a processor, or a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method for searching a wafer yield problem database, the wafer yield problem database being pre-established and including a plurality of failure categories, failure characteristics associated with the plurality of failure categories, and corresponding indicative data, the method comprising:

extracting a plurality of first failure features in the plurality of second wafer maps;

obtaining evidentiary data corresponding to the first failure category;

determining the matching quantity of the first failure category and the evidentiary data of each second failure category according to the similarity of the evidentiary data corresponding to the first failure category and the evidentiary data corresponding to each second failure category;

2. The method of claim 1, wherein the first ordering of the number of second failure categories according to the number of failure feature matches and the number of forensic data matches comprises:

3. The method of claim 2, wherein the weighted sum of the number of failed feature matches and the number of forensic data matches has a higher weight value than the number of failed feature matches.

4. The method of claim 1, wherein the failure characteristics comprise one or more of failure function composition characteristics, failure pattern shape characteristics, failure location characteristics, and failure pattern occurrence frequency characteristics.

5. The method of claim 1, wherein determining a number of second failure categories of the plurality of failure categories and a number of matching features of the first failure category with respective second failure categories based on similarities between the first failure features associated with the first failure category and the failure features associated with the plurality of failure categories comprises:

6. The method of claim 5, further comprising,

7. The method of claim 1, wherein presenting the number of second failure categories as a result of the first ordering includes,

and/or

8. The method of claim 1, further comprising,

9. The method of claim 1, further comprising,

10. An apparatus for searching a wafer yield problem database, the wafer yield problem database being pre-established and including a plurality of failure categories, failure characteristics associated with the plurality of failure categories, and corresponding indicative data, the apparatus comprising:

a failure mode exploring unit configured to determine, among the plurality of first wafer maps, a number of second wafer maps in which a predetermined failure mode exists;

a first failure type determination unit configured to determine a first failure type of each second wafer map according to the first failure feature;

a failure feature matching number determination unit configured to determine, according to similarities between first failure features related to the first failure category and failure features related to the plurality of failure categories, a number of second failure categories in the plurality of failure categories and a number of failure feature matches between the first failure category and each of the second failure categories, respectively;