A method for generating SDB isolation effect test structure and test structure

Abstract

The present invention provides a method for generating an SDB isolation effect test structure, including: obtaining layout information, and determining a test area in the layout; identifying a first MOA in the test area; recording a combination of a first SDB and a first MOA in contact with it as SDBseed1_cluster, and identifying a combination of two first MOAs in the SDBseed1_cluster as a test unit; laying a corresponding M1 on the first MOA to generate a strip of comb teeth, the comb teeth including a first comb tooth and a second comb tooth arranged at staggered intervals; forming the first comb tooth into a first comb structure, and forming the second comb tooth into a second comb structure; connecting the first comb structure and the second comb structure to different test ends, respectively, for testing the SDB isolation effect in the test unit. The steps are simple and can be applied to various practical designs for testing the isolation effect of SDB. The test structure provided by the present invention has a structure generated by the method of the present invention and has corresponding advantages.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor design and testing, and in particular relates to a method for generating a test structure for testing SDB isolation effect and a structure thereof. Background Art

[0002] Shallow trench isolation, or STI for short, is usually used in processes below 0.25µm. It uses a silicon nitride mask to deposit, pattern, and etch silicon to form a trench, which is then filled with deposited oxide for isolation from silicon. As integrated circuits are reduced to 14nm nodes or smaller, it becomes increasingly difficult to reduce the width of the shallow trench isolation area between active areas, resulting in the inability to further improve area utilization.

[0003] In order to solve this problem, in the prior art, a specially designed dummy gate is set between the two original effective active areas to form isolation, replacing the original shallow trench isolation method. For reference, Figure 1(a) shows that SDB isolation occupies a smaller area than STI isolation in Figure 1(b). This specially set dummy gate is called a single diffusion break (SDB), which is a structure used to electrically isolate the active areas on both sides of the SDB. However, how to effectively test whether the SDB really has a good isolation effect is still a technical problem in this field. Summary of the invention

[0004] The present invention is made based on the above-mentioned problems of the prior art, and aims to provide a method and structure for generating a SDB isolation effect test structure, which is suitable for testing the isolation effect of SDB.

[0005] The present invention provides a method for generating an SDB isolation effect test structure, step S1. acquiring layout information, including an active area, a gate, M0A, M0P, V0 and SDB, and determining a test area in the layout; the M0A is used to connect the active area; the M0P is used to connect the gate; the V0 is used to connect the M0A; the gate extension direction is taken as a first direction, and the second direction is perpendicular to the gate extension direction, and the SDB is used to electrically isolate the active areas on both sides thereof; step S2. identifying in the test area that the SDB that contacts the active areas on both sides is a first SDB, and the active areas that the first SDB contacts on both sides are the first active areas; identifying that the M0A located on the first active area, connected to V0, and not in contact with the M0P and non-first active areas is the first M0A; step S3. recording the combination of the first SDB and the first M0A on the first active area it contacts as SDBseed1 _cluster, and identify the combination of two first M0As in the SDBseed1_cluster as a test unit; identify V0 in the test unit as connection V0; step S4. lay the corresponding M1 on the first M0A in the test unit to generate strip-shaped comb teeth, and the connection V0 connects the first M0A and the comb teeth thereon; the comb teeth include first comb teeth and second comb teeth arranged at staggered intervals; step S5. connect the first comb teeth at one end in the first direction through M1 to form a first comb structure, and connect the second comb teeth at the other end in the first direction through M1 to form a second comb structure; the first comb structure and the second comb structure, as well as the connected test unit, constitute a test structure; the first comb structure and the second comb structure are respectively connected to different test ends for testing the SDB isolation effect in the test unit.

[0006] In a specific implementation, when laying M1 in step S4, it is ensured that M1 is within the test area and meets the preset layout design rules, and the test unit connected to M1 is discarded when M1 fails to meet the preset layout design rules.

[0007] Ensure that M1 is within the test area and meets the preset layout design rules. Specifically, when the vertical spacing between the edge connecting V0 and the M1 in the first direction does not meet the preset layout design rules, the edge of M1 in the first direction is translated outward until the vertical spacing meets the preset layout design rules, thereby achieving the extension of M1 in the first direction.

[0008] The test area determined in the layout in step S1 includes, from the outside to the inside, a first test area, a second test area and a third test area that are nested; the first test area is a rectangle, and the first comb structure and the second comb structure are therein, and the first comb structure and the second comb structure are used to test the SDB isolation effect in the third test area; the rectangular area obtained by translating the edge of the first test area inward by a preset first distance is the second test area; the rectangular area obtained by translating the edge of the second test area inward by a preset second distance is the third test area; the test unit in step S3 is in the third test area, and when M1 is laid in step S4, it is ensured that M1 is in the third test area. In a feasible implementation scheme, the test area determined in the layout in step S1 includes, from the outside to the inside, a first test area, a second test area and a third test area that are nested; the first test area is a rectangle, and the first comb structure and the second comb structure are therein, and the first comb structure and the second comb structure are used to test the SDB isolation effect in the third test area; the rectangular area obtained by translating the edge of the first test area inward by a preset first distance is the second test area; the rectangular area obtained by translating the edge of the second test area inward by a preset second distance is the third test area; the test unit in step S3 is in the third test area, and when laying M1 in step S4, ensure that M1 is in the third test area.

[0009] The second distance is the minimum spacing between M1s specified in the preset layout design rules.

[0010] In a particularly good practice, the second distance is 1µm.

[0011] Preferably, the first distance is 0.5µm.

[0012] In a preferred embodiment, one end of the first comb teeth in the first direction extends to the same straight line perpendicular to the first direction, and the other end of the second comb teeth in the first direction extends to the same straight line perpendicular to the first direction; and M1 connecting the first comb teeth together and / or M1 connecting the second comb teeth together are strip structures perpendicular to the first direction.

[0013] Optionally, the strip structure is between an edge of the first test area and an edge of the second test area; and a width of the strip structure in the first direction is equal to the first distance.

[0014] The width of the M1 laid in the step S4 in the second direction is equal to that of the first MOA.

[0015] In another feasible implementation scheme, in step S1, a plurality of test areas are determined in the layout, and a batch sampling test is performed on the SDB isolation effect in the layout.

[0016] Another aspect of the present invention provides a test structure, comprising a test terminal and a test area; the test area is obtained by using the above method for generating the SDB isolation effect test structure and is connected to the test terminal.

[0017] The present invention has the following beneficial effects: According to the method for generating an SDB isolation effect test structure involved in the present invention, (1) a method for forming a test structure by selecting several areas in a layout, retaining the front and middle section designs thereof, and automatically generating a metal layer M1, the process steps are simple and can be applied to various practical designs for testing the isolation effect of SDB. (2) A test structure provided by the present invention is obtained by using the method for generating an SDB isolation effect test structure of the present invention, which can realize the test of the SDB isolation effect and can perform a large-scale group sampling test on the SDB isolation part, which is convenient for subsequent winding to form a complete test chip, and is conducive to the optimization of production and design. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1( a ) and FIG. 1( b ) are schematic diagrams comparing SDB isolation and STI isolation.

[0019] Figure 2 It is a schematic diagram of a method for generating an SDB isolation effect test structure according to the first embodiment of the present invention.

[0020] Figure 3 It is a schematic diagram of the test area and the first SDB of the first embodiment of the present invention.

[0021] Figure 4 Schematic diagram of the first M0A and the first active area of ​​the first embodiment of the present invention.

[0022] Figure 5 It is a schematic diagram of a test unit according to the first embodiment of the present invention.

[0023] Figure 6 Schematic diagram of comb teeth of the first embodiment of the present invention.

[0024] Figure 7 It is a schematic diagram of the test structure of the first embodiment of the present invention.

[0025] Figure 8 It is a schematic diagram of the test structure of the second embodiment of the present invention. DETAILED DESCRIPTION

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments with reference to the following drawings.

[0027] The embodiments disclosed in the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments disclosed in the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments disclosed in the present invention are only for exemplary purposes and are not intended to limit the scope of protection disclosed in the present invention. The operations of the embodiments are described in a specific order in the following embodiments. The description of these orders is intended to better understand the details in the embodiments in order to fully understand the present invention, but the description of these orders does not necessarily correspond one-to-one with the method of the present invention, nor can it be used to limit the scope of the present invention.

[0028] It should be noted that the flowcharts and block diagrams in the accompanying drawings illustrate the operation process that may be implemented according to the method of the embodiment of the present invention. It should also be noted that in some alternative implementations, the functions marked in the boxes may also occur in a different order than the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed alternately, depending on the purpose to be achieved by the steps involved. In addition, each box in the block diagram and / or flow chart, and the combination of boxes in the block diagram and / or flow chart, can be implemented by a dedicated hardware-based system that performs the specified functions or operations, or can be implemented by a combination of dedicated hardware and manual operations.

[0029] Embodiment 1

[0030] like Figure 2As shown, in an embodiment of the present invention, a method for generating an SDB isolation effect test structure is disclosed, comprising: step S1. acquiring layout information, including an active area, a gate, M0A, M0P, V0 and SDB, and determining a test area in the layout; the M0A is used to connect the active area; the M0P is used to connect the gate; the V0 is used to connect the M0A; with the gate extension direction as the first direction and the second direction perpendicular to the gate extension direction, the SDB is used to electrically isolate the active areas on both sides thereof; step S2. identifying in the test area that the SDB that contacts the active areas on both sides is the first SDB, and the active areas that the first SDB contacts on both sides are the first active areas; identifying that the M0A on the first active area, connected to V0, and not in contact with the M0P and the non-first active area is the first M0A; step S3. recording the combination of the first SDB and the first M0A on the first active area it contacts as SDBsee d1_cluster, and identify the combination of two first M0As in the SDBseed1_cluster as a test unit; identify V0 in the test unit as connection V0; step S4. lay the corresponding M1 on the first M0A in the test unit to generate strip-shaped comb teeth, and the connection V0 connects the first M0A and the comb teeth thereon; the comb teeth include first comb teeth and second comb teeth arranged at staggered intervals; step S5. connect the first comb teeth at one end in the first direction through M1 to form a first comb structure, and connect the second comb teeth at the other end in the first direction through M1 to form a second comb structure; the first comb structure and the second comb structure, as well as the connected test unit, constitute a test structure; connect the first comb structure and the second comb structure to their respective different test ends, so as to test the SDB isolation effect in the test unit.

[0031] In this embodiment, reference Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7, the first direction Y and the second direction X are perpendicular to each other. In this embodiment, the test area determined in the layout in step S1 includes a first test area A, a second test area B and a third test area C. The first test area A is a rectangle. Each side of the rectangle is moved inward along a direction perpendicular to the side by a preset first distance, and the reduced rectangular area is the second test area B. In this embodiment, the first distance is set to 0.5µm. The first distance can also be other preset values. 0.5µm is a better example of the practice in this embodiment, and the present invention cannot be limited thereto. Similarly, each side of the second test area B is moved inward along a direction perpendicular to the side by a preset second distance, and the reduced rectangular area is the third test area C. In this example, the second distance is preset to 1µm, which is also the minimum distance between M1 lines specified in the preset layout design rules in this embodiment. Of course, this is just a better example of the practice in this embodiment, and the present invention cannot be limited thereto.

[0032] In this embodiment, in step S2, the SDB in contact with the active area on both sides in the third test area C is identified as the first SDB and is recorded as SDBseed1, and the active area in contact with the SDBseed1, that is, the first active area, is recorded as SDBseed1_asd. The M0A located on the SDBSeed1_asd, not in contact with other active areas except SDBSeed1_asd, not in contact with M0P, and connected to at least one V0 is identified as SDBseed1_M0A, that is, the first MOA. The combination of SDBseed1 and the SDBseed1_M0A on the SDBseed1_asd in contact with the SDBseed1 is recorded as SDBseed1_cluster, and the combination of two SDBseed1_M0A in the SDBseed1_cluster is recorded as SDBseed2_cluster, that is, it is identified as a test unit. The V0 in the SDBseed2_cluster is recorded as connection_V0, that is, connection V0. SDBseed2_cluster refers to the test unit automatically sampled and selected in the third test area C, which is used to test the SDB isolation effect in the test unit. The corresponding equal width M1 is laid on the SDBseed1_M0A in the SDBseed2_cluster to generate a strip of comb teeth, which is recorded as connection_valid. In this embodiment, the width of the laid M1 is equal to the width of the first M0A in the second direction X, which is a better example of practice. The width of the laid M1, that is, the width of the generated comb teeth can also be unequal to the first M0A, and is not limited. Connection_V0 is used to connect SDBseed1_M0A and the connection_valid thereon. When laying connection_valid, it is necessary to ensure that M1 is in the third test area C and meets the preset layout design rules, and when M1 fails to meet the preset layout design rules, the test unit SDBseed2_cluster connected to M1 is abandoned. In this embodiment, M1 satisfies the preset layout design rule: when the distance between connection_V0 connecting M1 and SDBseed1_M0A and the edge of M1 perpendicular to the first direction Y in the first direction Y does not reach the preset layout design rule (in this embodiment, the preset layout design rule is to ensure the enclosure of M1 to V0, which is an enclosure rule that limits the distance that the edge of M1 must exceed the edge of V0), the edge in the second direction X is moved outward from M1 along the first direction Y to a distance that satisfies the preset layout design rule, thereby realizing the extension of M1 in the gate extension direction.

[0033] All connection_valid are divided into connection_valid_A and connection_all_B, that is, the comb teeth include the first comb teeth and the second comb teeth arranged at staggered intervals. It should be noted that for the first comb teeth and the second comb teeth, there are also gaps in the first direction Y in some actual situations. It is necessary to extend the straight line of each connection_valid along the center line of the gate to see the first comb teeth and the second comb teeth arranged at intervals. That is, in this embodiment, connection_valid_A and connection_valid_B are arranged at intervals. If each connection_valid is taken as a straight line where the center line of the gate extension direction is located, then for every two adjacent connection_valid_A lines, there must be a connection_valid_B line, and for every two adjacent connection_valid_B lines, there must be a connection_valid_A line.

[0034] In this embodiment, after one end of all connection_valid_A is extended along the first direction Y to the edge of the second test area B, all the ends of connection_valid_A are connected together through M1 perpendicular to the first direction Y, and the strip structure generated by the M1 used to connect one end of connection_valid_A is recorded as connection_extension_A, and the comb structure composed of connection_extension_A and all connection_valid_A, that is, the first comb structure is recorded as comb_A. After one end of all connection_valid_B is extended in the opposite direction along the first direction Y to the edge of the second test area B, they are connected together through M1 perpendicular to the first direction Y, and the strip structure generated by the M1 used to connect one end of connection_valid_B is recorded as connection_extension_B, and the comb structure composed of connection_extension_B and all connection_valid_B, that is, the second comb structure is recorded as comb_B. It is a better practice in this embodiment that the strip structure is perpendicular to the first direction Y. In some other embodiments, the strip structure can also be at other angles with the first direction Y, which is not limited.

[0035] The strip structures connection_extension_A and connection_extension_B are graphic areas that are not in the second test area B but in the first test area A, and the width of connection_extension_A and connection_extension_B in the first direction Y is 0.5µm in this embodiment, which is equal to the first distance. This is a good example of this embodiment. In some other embodiments, the width of connection_extension_A and connection_extension_B in the first direction Y can also be less than or greater than the first distance, and is not limited. Comb_A and comb_B are connected to two different test terminals test1 and test2 respectively, that is, the SDB isolation in the test area is detected.

[0036] Embodiment 2

[0037] like Figure 8 As shown, the difference between the second embodiment and the first embodiment is that there are three test areas determined in step S1, each test area is independent of each other, and each test area includes a corresponding test unit and a comb structure, which is used to perform batch sampling tests on the SDB isolation effect in the layout, which is beneficial to improve the test efficiency. The three test areas determined are an example of this embodiment, and there can actually be more than three or two, which is set according to the application situation in actual production and is not limited.

[0038] It should be noted that the above examples are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and many variations are possible. All variations that can be directly derived or associated with the contents disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

[0039] The above embodiments are preferred examples of the present invention and are not intended to limit the scope of protection of the present invention. For the purpose of clear description, many implementation details are described together in the above description. However, it should be understood that these implementation details should not be used to limit the present invention.

Claims

1. A method for generating a SDB isolation effect test structure, characterized in that: include, Step S1. Obtain layout information, including active area, gate, M0A, M0P, V0 and SDB, and determine the test area in the layout; the M0A is used to connect the active area; the M0P is used to connect the gate; the V0 is used to connect the M0A; The gate extension direction is taken as a first direction, and the direction perpendicular to the gate extension direction is taken as a second direction, and the SDB is used to electrically isolate the active regions on both sides thereof; Step S2. In the test area, the SDB that contacts the active areas on both sides is identified as the first SDB, and the active areas that contact the first SDB on both sides are the first active areas; the M0A that is located on the first active area, connected to V0, and not in contact with the M0P and the non-first active area is identified as the first M0A; Step S3. Record the combination of the first SDB and the first MOA on the first active area it contacts as SDBseed1_cluster, and identify the combination of the two first MOAs in the SDBseed1_cluster as a test unit; identify V0 in the test unit as connection V0; Step S4. Laying the corresponding M1 on the first M0A in the test unit to generate strip-shaped comb teeth, wherein the connection V0 connects the first M0A and the comb teeth thereon; the comb teeth include first comb teeth and second comb teeth arranged at staggered intervals; Step S5. Connecting one end of the first comb teeth in the first direction through M1 to form a first comb structure, and connecting the other end of the second comb teeth in the first direction through M1 to form a second comb structure; the first comb structure and the second comb structure, as well as the connected test unit, form a test structure; The first comb structure and the second comb structure are connected to different test ends respectively to test the SDB isolation effect in the test unit.

2. The method for generating a SDB isolation effect test structure according to claim 1, characterized in that: When laying M1 in step S4, it is ensured that M1 is within the test area and meets the preset layout design rules, and when M1 fails to meet the preset layout design rules, the test unit connected to M1 is discarded.

3. The method for generating a SDB isolation effect test structure according to claim 2, characterized in that: Ensure that M1 is within the test area and meets the preset layout design rules, specifically: When the vertical spacing between the edge connecting V0 and the edge of M1 in the first direction does not meet the preset layout design rule, the edge of M1 in the first direction is translated outward until the vertical spacing meets the preset layout design rule, thereby extending the M1 in the first direction.

4. The method for generating a SDB isolation effect test structure according to claim 1, characterized in that: The test area determined in the layout in step S1 includes, from the outside to the inside, a first test area, a second test area, and a third test area that are nested; The first test area is rectangular, the first comb structure and the second comb structure are therein, and the first comb structure and the second comb structure are used to test the SDB isolation effect in the third test area; The rectangular area obtained by translating the edge of the first test area inwardly by a preset first distance is the second test area; the rectangular area obtained by translating the edge of the second test area inwardly by a preset second distance is the third test area; The test unit in step S3 is in the third test area, and when M1 is laid in step S4, it is ensured that M1 is in the third test area.

5. The method for generating a SDB isolation effect test structure according to claim 4, characterized in that: The second distance is the minimum spacing between M1s specified in the preset layout design rules.

6. The method for generating a SDB isolation effect test structure according to claim 4, characterized in that: One end of the first comb teeth in the first direction extends to the same straight line perpendicular to the first direction, and the other end of the second comb teeth in the first direction extends to the same straight line perpendicular to the first direction; and M1 connecting the first comb teeth together and / or M1 connecting the second comb teeth together are strip structures perpendicular to the first direction.

7. The method for generating a SDB isolation effect test structure according to claim 6, characterized in that: The strip structure is between the edge of the first test area and the edge of the second test area; the width of the strip structure in the first direction is equal to the first distance.

8. The method for generating a SDB isolation effect test structure according to claim 1, characterized in that: The width of the M1 laid in the step S4 in the second direction is equal to that of the first MOA.

9. A method for generating a SDB isolation effect test structure according to any one of claims 1 to 8, characterized in that: In step S1, a plurality of test areas are determined in the layout, and a batch sampling test is performed on the SDB isolation effect in the layout.

10. A test structure, characterized in that: The test structure in the test area is obtained by using the method for generating the SDB isolation effect test structure described in any one of claims 1 to 9, and is used to connect to the test end to test the SDB isolation effect in the test area.

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