Semiconductor structures having dummy regions

Abstract

A semiconductor structure and a method for manufacturing the same include a substrate having a device region and a dummy region. The device region includes a plurality of N-type device cells having a plurality of operating N-type transistors and a plurality of P-type device cells having a plurality of operating P-type transistors. The dummy region includes a plurality of N-type dummy cells having a plurality of non-operating N-type transistors and a plurality of P-type dummy cells having a plurality of non-operating P-type transistors, and the total number of N-type device cells and P-type device cells is equal to the total number of N-type dummy cells and P-type dummy cells.

Description

Technology Field [Priority Data] This application claims priority to Provisional Application No. 63 / 651,546 filed on May 24, 2024, the entirety of which is incorporated herein by reference. The present invention relates to a semiconductor structure having a dummy region. Background Technology The semiconductor integrated circuit (IC) industry is experiencing rapid growth. Technological advancements in IC materials and design are producing generations of ICs in which each generation features smaller and more complex circuits than the previous one. In the evolution of ICs, functional density (i.e., the number of interconnected devices per chip area) generally increases, while geometric size (i.e., the minimum component (or line) that can be produced using the manufacturing process) decreases. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. This scaling down has also increased the complexity of IC processing and manufacturing, and similar developments in IC processing and manufacturing are required to realize this progress. This scaling down is also increasing the complexity of IC processing and manufacturing. For example, as integrated circuit (IC) technology advances toward smaller technology nodes, multi-gate devices have been introduced to improve gate control by increasing gate-channel coupling, reducing off-state current, and mitigating short-channel effects (SCE). Multi-gate devices generally refer to devices having gate structures or parts thereof positioned over more than one side of the channel region. Fin-like field effect transistors (FinFETs) and gate-all-around (GAAs) transistors are examples of multi-gate devices that have become popular and promising candidates for high-performance and low-leakage applications. Planar transistors can also be implemented for various performance considerations. Existing technologies for manufacturing semiconductor structures including device regions and dummy regions are generally sufficient for their intended purposes, but have not been completely satisfactory in all aspects. Prior art literature U.S. Patent Application Publication US2024 / 0096947 (March 21, 2024) Brief explanation of the drawing This disclosure is best understood from the specific details of how the invention described below is carried out when read together with the accompanying drawings. In accordance with standard practice in the art, it is emphasized that the various features are not drawn to actual scale and are used for illustrative purposes only. In fact, the dimensions of the various features may be increased or decreased at will to clarify the discussion. FIG. 1 is a flowchart of an exemplary method for designing a layout according to various embodiments of the present disclosure. FIGS. 2a and 2b are partial plan views of exemplary semiconductor structures according to various embodiments of the present disclosure. FIG. 3a illustrates a partial layout pattern of a subregion of an exemplary semiconductor structure according to various embodiments of the present disclosure. FIG. 3b illustrates an enlarged portion of a sub-region of an exemplary semiconductor structure according to various embodiments of the present disclosure. FIG. 4a illustrates a partial cross-sectional view of an enlarged portion following AA shown in FIG. 3b according to various embodiments of the present disclosure. FIG. 4b illustrates a partial cross-sectional view of an enlarged portion along the BB shown in FIG. 3b according to various embodiments of the present disclosure. FIG. 4c illustrates a partial cross-sectional view of an enlarged portion according to CC shown in FIG. 3b according to various embodiments of the present disclosure. FIG. 4d illustrates a partial cross-sectional view of an enlarged portion along DD shown in FIG. 3b according to various embodiments of the present disclosure. FIG. 4e illustrates a partial cross-sectional view of an enlarged portion following the EE shown in FIG. 3b according to various embodiments of the present disclosure. FIGS. 5A, FIGS. 5B, FIGS. 5C, FIGS. 5D, and FIGS. 5E illustrate partial alternative layout patterns of subregions of an exemplary semiconductor structure according to a first alternative embodiment of the present disclosure. FIGS. 6a, FIGS. 6b, FIGS. 6c, FIGS. 6d, FIGS. 6e, and FIGS. 6f illustrate partial alternative layout patterns of subregions of an exemplary semiconductor structure according to a second alternative embodiment of the present disclosure. FIGS. 7a, 7b, 7c, 7d, 7e, and 7f illustrate partial alternative layout patterns of subregions of an exemplary semiconductor structure according to a third alternative embodiment of the present disclosure. FIGS. 8a, FIGS. 8b, FIGS. 8c, FIGS. 8d, FIGS. 8e, and FIGS. 8f illustrate partial alternative layout patterns of subregions of an exemplary semiconductor structure according to a fourth alternative embodiment of the present disclosure. FIGS. 9a, FIGS. 9b, FIGS. 9c, FIGS. 9d, FIGS. 9e, and FIGS. 9f illustrate partial alternative layout patterns of subregions of an exemplary semiconductor structure according to a fifth alternative embodiment of the present disclosure. FIGS. 10a, FIGS. 10b, and FIGS. 10c illustrate partial alternative layout patterns of subregions of an exemplary semiconductor structure according to a sixth alternative embodiment of the present disclosure. FIG. 11 illustrates a partial alternative layout pattern of a sub-region of an exemplary semiconductor structure according to the seventh alternative embodiment of the present disclosure. FIG. 12 illustrates a partial alternative layout pattern of a sub-region of an exemplary semiconductor structure according to the eighth alternative embodiment of the present disclosure. FIG. 13 is a flowchart of an exemplary method for manufacturing a semiconductor structure according to various embodiments of the present disclosure. FIGS. 14a, FIGS. 15a, FIGS. 16a, FIGS. 17a, FIGS. 18a, FIGS. 19a, and FIGS. 20a illustrate partial cross-sectional views of a semiconductor structure taken along line C-C' as shown in FIG. 3b during various manufacturing stages in the method of FIG. 13 according to various embodiments of the present disclosure. FIGS. 14b, FIGS. 15b, FIGS. 16b, FIGS. 17b, FIGS. 18b, FIGS. 19b, and FIGS. 20b illustrate partial cross-sectional views of a semiconductor structure taken along line EE as shown in FIG. 3b during various manufacturing stages in the method of FIG. 13 according to various embodiments of the present disclosure. FIGS. 14c, FIGS. 15c, FIGS. 16c, FIGS. 17c, FIGS. 18c, FIGS. 19c, and FIGS. 20c illustrate partial cross-sectional views of a semiconductor structure taken along line D-D' as shown in FIG. 3b during various manufacturing stages in the method of FIG. 13 according to various embodiments of the present disclosure. FIG. 21 is a block diagram of a system for implementing one or more embodiments of the present disclosure including the method of FIG. 1. Specific details for implementing the invention The following description provides a number of different embodiments or examples for implementing different features of the provided subject matter. To simplify the disclosure, specific embodiments of components and configurations are described below. Of course, these are merely examples and are not intended to be limiting. For example, in the following description, the formation of a first feature over or on a second feature may include an embodiment in which the first and second features are formed in direct contact, and may also include an embodiment in which additional features are formed between the first feature and the second feature so that the first feature and the second feature do not come into direct contact. Additionally, the disclosure may repeat reference numbers and / or letters in various embodiments. Such repetition is for the purpose of simplicity and clarity and does not itself indicate a relationship between the various embodiments and / or configurations described. Spatial terms such as "below," "under," "low," "high," and "upper" may be used for convenience of description to indicate the relationship of a feature to one element or another as illustrated in the drawings. Spatial terms are intended to include different orientations of the device during use or operation, in addition to the orientations shown in the drawings. The device may be oriented in different ways (rotated 90 degrees or in other directions), and spatial descriptors used herein may be interpreted accordingly. Additionally, when a number or a range of numbers is described as "about," "approximately," etc., the term is intended to include a number within a reasonable range that takes into account variations inherently occurring during the manufacturing process, as understood by a person skilled in the art. For example, a number or a range of numbers encompasses a reasonable range including the stated number, such as within ±10% of the stated number, based on known manufacturing tolerances associated with manufacturing a feature having the characteristics associated with the number. For example, a material layer having a thickness of "about 5 nm" may encompass a dimensional range of 4.25 nm to 5.75 nm, provided that the manufacturing tolerance associated with depositing the material layer is known to be ±15% by those skilled in the art. Furthermore, the present disclosure may repeat reference numbers and / or letters in various examples. Such repetition is for the purpose of simplicity and clarity and does not imply a relationship between the various embodiments and / or configurations described. When forming a semiconductor structure such as a semiconductor chip, active semiconductor devices such as transistors are formed on a substrate. The transistors may be advanced transistors, such as fin-type field-effect transistors (FinFETs) or gate-all-around (GAA) transistors, or planar transistors. The transistors may be part of an integrated circuit (IC). The transistors fabricated on the substrate may be p-type transistors or n-type transistors. P-type transistors may be P-type metal-oxide-semiconductor (PMOS) transistors (e.g., including p-type source / drain features). N-type transistors may be N-type metal-oxide-semiconductor (NMOS) transistors (e.g., including n-type source / drain features). PMOS and NMOS transistors are formed within the device region of the substrate. In particular, the semiconductor structure includes a plurality of active regions (or "oxide definitions" (OD)) where the transistors are formed. The active region defines the area for each transistor, that is, the region where the transistor's source / drain features and channel regions are formed. The active region is defined between isolation regions provided by shallow trench isolation (STI) or field oxide (FOX) regions. Semiconductor devices, such as the transistors discussed above, are active devices formed on device regions of the substrate, along with passive devices in some cases. The substrate also includes dummy regions that may not contain functional devices. Semiconductor structures are formed starting with a design process. Computer-aided design (CAD) and electronic design automation (EDA) tools enable the design of these semiconductor devices. In some embodiments, the circuit design process begins with specifications that describe the desired functions of a semiconductor structure (e.g., an integrated circuit) and may include various performance requirements. Subsequently, in the logic design phase, the logical implementation of the semiconductor structure is described using one of several hardware description languages ​​[e.g., Verilog or VHDL at the register transfer logic (RTL) abstraction level]. EDA software tools can use libraries to synthesize abstract logic into a technology-dependent netlist. The output can also describe the behavior of circuits on the chip as well as the interconnections of inputs and outputs. After the logic design phase, the design proceeds to the physical design phase. The physical design generates a semiconductor structure design (e.g., chip design). The physical design includes various steps, including floor planning, placement and routing, layout versus schematic (LVS), and design rule check (DRC) determination. Once the design of a semiconductor structure, such as an integrated circuit chip, is completed, a file containing the layout of the semiconductor structure [e.g., a graphic data system (GDS) file] is generated. Subsequently, the information is provided to a manufacturing facility [e.g., taped-out]. Then, masks defining the layers of the layout are manufactured and used to manufacture the semiconductor structure itself. The present disclosure includes features that may be represented in the layout during the design process. One consideration in the logic design phase, and particularly in the physical design phase, is across-chip uniformity. Depending on the design, specific semiconductor manufacturing processes used to manufacture the chip introduce physical variation across the structure. Physical variation can lead to electrical performance and reliability issues. Accordingly, dummy regions are provided in a semiconductor structure (e.g., a chip) that includes functional / operational device regions (e.g., including active semiconductor devices such as the transistors discussed above). Dummy regions (or "non-functional regions") may include dummy transistors or components that do not provide electrical function to the semiconductor structure (e.g., are not interconnected). Dummy regions can mitigate loading effects during patterning, etching, polishing, film deposition, and / or other manufacturing processes. The present disclosure provides semiconductor structures, systems, and methods for defining dummy regions. The present disclosure provides designs for dummy regions that may be formed on a substrate together with device regions. In semiconductor structure design, a standard cell is a block of transistors that repeats according to a set of design rules across a design layout. Standard cells can be used for different functions. For example, a standard cell may be a static random access memory (SRAM) cell or a logic cell for logic operations. A standard cell may include one or more p-type transistors and one or more n-type transistors. In some embodiments, cells that are dummy cells may also be formed. The present disclosure includes dummy region layouts that may be provided as cells for implementation within a semiconductor structure as discussed below. FIG. 1 illustrates a method (100) that can be implemented to form a semiconductor structure layout. In an embodiment, the semiconductor structure is a chip, in particular an integrated circuit (IC) chip. The method (100) is merely illustrative and is not intended to limit the disclosure to what is explicitly illustrated herein. Additional steps may be provided before, during, and after the method (100), and some of the steps described may be replaced, deleted, or moved for additional embodiments of the method. For the sake of brevity, not all steps are described herein in detail. Referring to FIGS. 1 and FIGS. 2a through 3b, the method (100) comprises block 102, wherein device regions (204A) (or "functional regions (204A)") are identified on a layout of a semiconductor structure in a design process such as the physical design process discussed above. Features of semiconductor devices (e.g., gate structures) within the device regions (204A) may be operational (e.g., contributing to the function of the device). The method (100) and block (102) may be used to define a layout of semiconductor devices including active and passive devices, but are not limited thereto. Examples of active devices include, but are not limited to, transistors including metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJTs), high-voltage transistors, high-frequency transistors, p-channel and / or n-channel field effect transistors (PFETs / NFETs), FinFETs, GAA devices, nanosheet transistors (included as examples below), planar MOS transistors including elevated source / drain, etc. Other active devices include diodes. Examples of passive elements include, but are not limited to, capacitors, inductors, fuses, resistors, etc. The layout may include interconnect features that couple one or more of the active and passive devices together and to the input / output terminals of the semiconductor structure. In some embodiments, the device regions (204A) of the substrate may be configured to form a memory structure comprising a plurality of SRAM cells. Each SRAM cell comprises a plurality of N-type transistors and a plurality of P-type transistors. For example, a 6-transistor SRAM cell comprises four N-type transistors and two P-type transistors. Accordingly, for embodiments in which the device region (204A) is a memory structure comprising a plurality of 6T SRAM cells, the total number of functional N-type transistors in the device region (204A) may be greater than the total number of functional P-type transistors in the device region (204A). That is, the total number of N-type epitaxial source / drain features (NEPI) in the device region (204A) may be greater than the total number of P-type epitaxial source / drain features (PEPI) in the device region (204A). In other examples, the device regions (204A) may be configured to form a plurality of logic cells. For example, a NOR gate may include two N-type transistors and two P-type transistors. Accordingly, to form logic cells, the total number of N-type epitaxial source / drain features (NEPIs) in the device region (204A) may be equal to the total number of P-type epitaxial source / drain features (PEPIs) in the device region (204A). As a result, depending on various design requirements of the device region (204A), the total number of NEPIs in the device region (204A) may be greater than, equal to, or less than the total number of PEPIs in the device region (204A). A sub-region of the device region (204A) for forming a functional N-type transistor containing NEPIs may be referred to as a functional N-type cell, and a sub-region of the device region (204A) for forming a functional P-type transistor containing PEPIs may be referred to as a functional P-type cell.That is, N-type cells are defined for N-type transistors, and P-type cells are defined for P-type transistors. Depending on the various design requirements of the device region (204A), the number of functional P-type cells in the device region (204A) may be greater than, equal to, or smaller than the number of functional N-type cells in the device region (204A). Referring again to FIGS. 1 and FIGS. 2a through 3b, the method (100) includes a block 104 in which a dummy region (204B) is defined on a layout for a semiconductor structure. Operations in block 104 may be performed simultaneously with operations in block 102. The dummy region (204B) may include devices or features that do not provide electrical function to the semiconductor structure (e.g., IC chip). In other words, the features (e.g., gate structures) or devices of the dummy region (204B) may not operate and may be referred to as dummy features or dummy devices (e.g., dummy N-type transistors, dummy P-type transistors). The dummy region (204B) may include a structure realized using substantially the same manufacturing process as the device region. The dummy region(s) (204B) may be adjacent device regions (204A). For example, in the exemplary embodiment illustrated in FIG. 2b, when viewed from above, the dummy region (204B) surrounds the device region (204A). Referring again to FIGS. 1 and FIGS. 2a through 3b, the method (100) includes a block 106 in which a layout pattern of a dummy region (204B) is determined. In some embodiments, the dummy region (204B) includes transistor features (e.g., channel regions, gate structures, NEPI, PEPI) that are substantially identical to the features forming the transistors of the device region (204A), for example. In some additional embodiments, the transistor features of the dummy region (204B) are not connected (e.g., have no contacts) so as not to be interconnected with each other and / or with the input / output (I / O) of the semiconductor structure (e.g., IC chip). In particular, in some embodiments, operations in block 106 include defining specific sub-regions of a dummy region (204B) containing dummy N-type transistors substantially similar to functional n-type transistors in a device region (204A). In an embodiment, source / drain regions for forming NEPIs [including both NEPIs in the device region (204A) and NEPIs in the dummy region (204B)] in the manufacture of the chip are defined by a first masking element that simultaneously provides both first openings in the device region (204A) and second openings in the dummy region (204B). The first openings in the device region (204A) enable the formation of NEPIs of functional n-type transistors, and the second openings in the dummy region (204B) enable the formation of NEPIs of dummy n-type transistors. NEPIs are formed on portions of active regions exposed by the first opening or the second opening. In an embodiment, the NEPIs in the dummy region (204B) are substantially similar to and simultaneously formed with the NEPIs in the device region (204A). Operations in block 106 further include defining specific sub-regions of a dummy region (204B) containing dummy P-type transistors substantially similar to the functional p-type transistors in the device region (204A). Sub-regions of the dummy regions (204B) for forming dummy N-type transistors containing NEPIs may be referred to as dummy P-type cells, and sub-regions of the dummy regions (204B) for forming dummy P-type transistors containing PEPIs may be referred to as dummy P-type cells. Source / drain regions for forming PEPIs [including both PEPIs in the device region (204A) and PEPIs in the dummy region (204B)] in the manufacture of the chip are defined by a second masking element that simultaneously provides both third openings in the device region (204A) and fourth openings in the dummy region (204B). The third openings in the device region (204A) enable the formation of PEPIs of functional P-type transistors, and the fourth openings in the dummy region (204B) enable the formation of PEPIs of dummy P-type transistors. PEPIs are formed on portions of the active regions exposed by the third openings or the fourth openings. In an embodiment, PEPIs within the dummy region (204B) are substantially similar to and simultaneously formed with PEPIs within the device region (204A). In the present disclosure, dummy N-type cells and functional N-type cells may be substantially identical in structural aspects, and dummy N-type cells and functional N-type cells may use the same reference numeral (e.g., 304 shown in FIG. 3a), and dummy P-type cells and functional P-type cells may be substantially identical in structural aspects, and dummy P-type cells and functional P-type cells may use the same reference numeral (e.g., 302 shown in FIG. 3a). In the present disclosure, operations in block 106 include forming specific sub-regions to form dummy structures including active regions and non-functional gate structures, but do not include forming any of NEPIs and PEPIs. These sub-regions without NEPIs and PEPIs may be referred to as blank cells. The source / drain regions of the active regions within the blank cells are not exposed by either the openings of the first masking element or the openings of the second masking element. The opening ratio of the first masking element providing openings to form NEPIs (or "NEPI openings") affects the critical dimension ("CD") of the NEPIs. That is, a small opening ratio for the NEPIs (e.g., fewer NEPIs) can provide a larger NEPI CD. In some embodiments, the configurations (e.g., distributions, numbers) of the NEPIs and PEPIs within the dummy region (204B) allow the distribution of the EPI critical dimension (CD) among the devices of the semiconductor structure (e.g., chip) to converge. The operations in block 106 further include operations for determining layout patterns of dummy N-type cells, dummy P-type cells, and dummy blank cells so that the difference between the open ratio of NEPIs and the open ratio of PEPIs across the entire device region (204A) and dummy region (204B) can be reduced or even eliminated. In some embodiments, the number and distribution of dummy N-type cells, dummy P-type cells, and dummy blank cells within the dummy region (204B) enable convergence of the EPI critical dimension (CD) distribution among the devices of the semiconductor structure (e.g., chip). The configuration of the layout pattern of the dummy region (204B), including the location and amount of dummy N-type cells, dummy P-type cells, and blank cells, is optionally determined based on the configuration of the device region (204A) of block 102. In the present disclosure, the total number of dummy N-type cells in the dummy region (204B) and functional N-type cells in the device region (204A) is equal to the total number of dummy P-type cells in the dummy region (204B) and functional P-type cells in the device region (204A). In an embodiment, in the device region (204A), the number of functional N-type cells is equal to the number of functional P-type cells, and in the dummy region (204B), the number of dummy N-type cells is equal to the number of dummy P-type cells. In other embodiments, in the device region (204A), the number of functional N-type cells is greater than the number of functional P-type cells, and in the dummy region (204B), the number of dummy N-type cells is less than the number of dummy P-type cells. In another embodiment, in the device area (204A), the number of functional N-type cells is smaller than the number of functional P-type cells, and in the dummy area (204B), the number of dummy N-type cells is larger than the number of dummy P-type cells.For embodiments in which the locations and number of functional N-type cells and functional P-type cells within the device area (204A) are predetermined, the number of dummy N-type cells and dummy P-type cells within the dummy area (204B) can be flexibly arranged to achieve the aforementioned converging EPI critical dimension (CD) distribution. In another embodiment, the number of blank cells within the dummy area (204B) can be flexibly adjusted to improve design flexibility, reduce defects within the device area (204A), and reduce the cost of forming NEPIs and PEPIs. In another embodiment, the locations of dummy N-type cells and dummy P-type cells within the dummy area (204B) can be flexibly arranged within the dummy area (204B) so that the devices within the device area (204A) can have fewer defects. The method (100) further includes block 108 in which additional processes are performed. These additional processes may include additional design processes such as design rule checking, tape-out of the layout, manufacturing of photomasks according to the layout, and manufacturing of a semiconductor structure according to the photomasks. The manufactured semiconductor structure may include a dummy region having a plurality of N-type dummy cells having NEPIs and a plurality of P-type dummy cells having PEPIs, and in some embodiments, a plurality of blank cells not having NEPIs and PEPIs. Referring to FIG. 2a, a segment of a plan view of a semiconductor structure (200) is illustrated. The plan view includes a chip boundary region (202). The region between the edge of the semiconductor structure (200) and the chip boundary region (202) may provide an exclusion region that may not include any active or passive semiconductor devices. The semiconductor structure (200) includes a plurality of sub-regions (204). The sub-regions (204) may be similar to one another. In an embodiment, the various sub-regions (204) may be patterned to include different features. In an embodiment, the sub-regions (204) are formed by the same pattern. For reference purposes, a dashed line illustrates the stepping field of the photolithography process in an embodiment. In some embodiments, the stepper distance may be similar to the width of the sub-region (204) in the x-direction. In an embodiment, the sub-regions (204) define areas of, for example, approximately 18 μm x 18 μm in the manufactured device. Other suitable sizes are also possible. In some other embodiments, the stepper distance may be half the width of the sub-region (204) in the x-direction. The sub-region (204) may include a device region (204A) and a dummy region (204B) as illustrated in FIG. 2b. The device region (204A) may be defined as discussed above with reference to block 102 of the method (100). The dummy region (204B) may be defined as discussed above with reference to blocks 104-106 of the method (100). Each of the device region (204A) and the dummy region (204B) includes a plurality of active regions where semiconductor devices, such as transistors, are formed. For example, gate structures and source / drain features may be formed on the active regions. Each of the sub-regions (204), device regions (204A), and dummy regions (204B) is not limited to the illustrated rectangular plans, and, for example, polygonal structures including triangular, pentagonal, and octagonal structures and circular structures including elliptical structures may be adopted without departing from the technical concept of the present invention. The device region (204A) may include functional n-type transistors, for example, NEPIs, channel regions, and gate structures for functional n-type transistors; and functional p-type transistors, for example, PEPIs, channel regions, and gate structures for functional p-type transistors. The dummy regions (204B) may include dummy n-type transistors, dummy p-type transistors, and blank cells. Dummy n-type transistors may be formed together with functional n-type transistors, and dummy p-type transistors may be formed together with functional p-type transistors. In some embodiments, the functional transistors in the device region (204A) and the dummy transistors in the dummy regions (204B) are realized using substantially the same manufacturing processes and have substantially the same internal structure. The blank cells in the dummy region (204B) may be realized using substantially the same manufacturing processes as the functional or dummy transistors, but have different internal structures. In some embodiments, transistors formed in the dummy region (204B) do not provide functionality to the formed structure (e.g., are not interconnected), while transistors formed in the device region (204A) are interconnected to form IC functionality of the structure (e.g., a chip). A semiconductor substrate (201) is provided when manufactured as a semiconductor structure (200). In an embodiment, the substrate (201) comprises silicon. Alternatively or additionally, the substrate (201) comprises another base semiconductor such as germanium; a compound semiconductor such as silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, and / or indium antimonide; an alloy semiconductor such as silicon germanium (SiGe), GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and / or GaInAsP; or a combination thereof. Alternatively, the substrate (201) is a semiconductor-on-insulator substrate such as a silicon-on-insulator (SOI) substrate, a silicon germanium-on-insulator (SGOI) substrate, or a germanium-on-insulator (GOI) substrate. Semiconductor-on-insulator substrates can be manufactured using separation by implantation of oxygen (SIOX), wafer bonding, and / or other suitable methods. In some embodiments, the selection of the number and configuration of dummy P-type cells (302), dummy N-type cells (304), and / or blank cells (306) may be performed as part of block 106 of the method (100). That is, the configuration of the dummy region (204B) may be dynamically adjusted based on the determined layout of the device region (204A). In some embodiments, the distribution of dummy P-type cells (302), dummy N-type cells (304), and / or blank cells (306) within the dummy region (204B) enables the convergence of the EPI critical dimension (CD) distribution among the devices of the semiconductor structure (e.g., chip). As discussed above, the dummy P-type cells (302) and dummy N-type cells (304) may be defined by corresponding masking elements formed in a photolithography process during the manufacture of the semiconductor substrate corresponding to the layouts of the sub-regions (204). The opening ratio of the mask element providing the NEPI aperture affects the NEPI CD. That is, a smaller opening ratio for the NEPI (e.g., fewer NEPI regions) can provide a larger NEPI CD. FIG. 3a illustrates a fragmentary layout view of a part of a semiconductor structure (200) (e.g., a sub-region (204)). The layout may be created and stored using the method (100) of FIG. 1 and / or the system (2100) of FIG. 21. The embodiment illustrated by FIG. 3a illustrates one configuration of the sub-region (204). Other possible configurations of the sub-region (204) are described below with reference to FIG. 5a through FIG. 12. Generally, in this disclosure, the layout or plan views are also examples of the semiconductor structure corresponding to the layout, since the layout will be manufactured into a semiconductor structure at the end of the manufacturing processes. Referring to FIG. 3a, the device region (204A) comprises P1 number of functional P-type cells (302) having p-type transistors and N1 number of functional N-type cells (304) having n-type transistors, where P1 is greater than or equal to 0 and N1 is greater than or equal to 0. As discussed above, depending on the various design requirements of the device region (204A), the number of functional P-type cells (P1) of the device region (204A) may be greater than, equal to, or less than the number of functional N-type cells (N1) of the device region (204A). In this illustrated embodiment, the device region (204A) has more functional P-type cells (302) than functional N-type cells (304). That is, the number N1 is less than the number P1. In the embodiment, the ratio of the number N1 to the number P1 is substantially 1:2. The positional arrangement of the functional P-type cells (302) and functional N-type cells (304) in the device area (204A') is merely an example and is not intended to be limiting. The dummy region (204B) comprises P2 dummy P-type cells (302) having p-type transistors, N2 dummy N-type cells (304) having n-type transistors, and M blank cells (306), wherein P2 is 0 or greater, N2 is 0 or greater, and M is 0 or greater. In the present disclosure, to achieve a converged EPI threshold dimension (CD) distribution among devices of a semiconductor structure (e.g., a chip), the total number of dummy N-type cells (304) in the dummy region (204B) and functional N-type cells (304) in the device region (204A) (i.e., N1+N2) is equal to the total number of dummy P-type cells in the dummy region (204B) and functional P-type cells in the device region (204A) (i.e., P1+P2). That is, the sub-region (204) includes an equal number of P-type cells (including both dummy and functional P-type cells) and N-type cells (including both dummy and functional N-type cells). The dummy P-type cells (302) and the functional P-type cells (302) may be collectively referred to as P-type cells (302), and the dummy N-type cells (304) and the functional N-type cells (304) may be collectively referred to as N-type cells (304). In this illustrated embodiment, the cells of the sub-region (204) [i.e., P-type cells (302), N-type cells (304), and blank cells (306)] are arranged in a 12 x 12 (column x row) array, the number of N1s is 16, and the number of P1s is 32. That is, the ratio of the number of P1s to the number of N1s is substantially 2. The number of N2 is 40, and the number of P2 is 24. That is, the ratio of the number of N2 to the number of P2 is substantially less than 2. The number of M is 32. As a result, the sub-region (204) includes an equal number of N-type cells and P-type cells (i.e., 56 in this embodiment). In the present disclosure, forming blank cells (306) provides additional advantages.For example, forming blank cells (306) within a dummy region (204B) reduces the total number of NEPIs and / or PEPIs to be formed on the substrate (201) without affecting the converged EPI critical dimension (CD) distribution, thereby reducing manufacturing costs. In this illustrated embodiment, the ratio of the number of M to the total number of cells (e.g., 302, 304, 306) in the sub-region (204) (i.e., N1+N2+P1+P2+M) is about 22%. In some embodiments, the ratio may be adjusted. That is, the sub-region (204) may have a different number of blank cells. By adjusting the percentage of blank cells (306), the arrangement of dummy P-type cells (302) and dummy N-type cells (304) can be dynamically adjusted so that the ratio of P-type cells (302) to N-type cells (304) can be adjusted to achieve desired device functions and performance. In the present disclosure (including embodiments described with reference to FIGS. 3a through 15), the ratio of M to the total number of cells in the sub-region (204) (i.e., N1+N2+P1+P2+M) is less than about 45%. If the ratio is greater than 45%, the total number of N-type cells (304) may be equal to the total number of P-type cells to achieve a converged EPI threshold dimension (CD) distribution, and the CDs of the NPEIs and PEPIs may be substantially the same, but the NPEIs and PEPIs take up less area, and the CDs of these EPIs become too large, resulting in unwanted parasitic capacitance. For embodiments in which blank cells (306) are placed right next to the device area (204A), as shown in FIG. 3a, the blank cells (306) can also act as a defect barrier to protect the functional cells within the device area (204A), thereby improving device performance.In this illustrated embodiment, the device area (204A) has more functional P-type cells (302) than functional N-type cells (304), and to further reduce defects in the device area (204A) to improve device performance, the dummy N-type cells (304) are arranged closer to the device area (204A) than the dummy P-type cells (304). That is, the distance between the dummy N-type cells (304) and the device area (204A) is smaller than the distance between the dummy P-type cells (304) and the device area (204A). In other words, the device area (204A) containing more functional P-type cells (302) is separated from the dummy P-type cells (302) by the dummy N-type cells (304). In this illustrated embodiment, the dummy P-type cells (302) are also separated from the blank cells (306) by the dummy N-type cells (304). FIG. 3b illustrates a partial layout view of a portion of a sub-region (204) illustrating an N-type cell (304), a blank cell (306), and a P-type cell (302) illustrated in FIG. 3a. Each of two adjacent cells in the sub-region (204) may be isolated by isolation features such as isolation features (402) and a dielectric structure (412) discussed below. FIG. 4a illustrates a cross-sectional view of a portion of a sub-region (204) taken along line AA as shown in FIG. 3b, FIG. 4b illustrates a cross-sectional view of a portion of a sub-region (204) taken along line BB as shown in FIG. 3b, FIG. 4c illustrates a cross-sectional view of a portion of a sub-region (204) taken along line CC as shown in FIG. 3b, FIG. 4d illustrates a cross-sectional view of a portion of a sub-region (204) taken along line DD as shown in FIG. 3b, and FIG. 4e illustrates a cross-sectional view of a portion of a sub-region (204) taken along line EE as shown in FIG. 3b.

[0055] As illustrated in FIG. 3b, a plurality of gate structures (404) extend in the Y direction in the top view. In some embodiments, the gate structures (404) of the N-type cell (304) are substantially in alignment with the gate structures (404) of the P-type cell (302) and the gate structures (404) of the blank cell (306). In an embodiment, a dielectric structure (412) (illustrated in FIG. 4a) is interposed between the gate structures (404) of the P-type cell (302) and the gate structures (404) of the blank cell (306), and between the gate structures (404) of the N-type cell (304) and the gate structures (404) of the blank cell (306). The gate structures (404) extend over each active region (406). In some embodiments as illustrated in FIG. 3b, the active regions (406) each extend in the X direction in the top view. In this illustrated embodiment, the active region (406) comprises fin elements. The fin elements extend vertically (e.g., in the Z direction) from the top surface of the substrate (201) and provide a plurality of sides and channel regions accessible from the top surface. In the top view, the fin elements may extend in the X direction substantially perpendicular to the gate structures (404). In other embodiments, the active region (406) comprises a planar semiconductor substrate region. In other embodiments, such as the embodiment to be described with reference to FIGS. 20a through 20c, the active region (406) comprises a plurality of nanostructures (e.g., nanowires or nanosheets) providing channel regions. In an embodiment, the active region (406) is silicon. However, other semiconductor materials as discussed below may additionally or alternatively be implemented for the substrate. There are isolation features (402) between the active regions (406). The isolation features (402) may also be referred to as shallow trench isolation (STI) features. In some embodiments, the isolation features (402) may include silicon oxide, silicon nitride, silicon oxynitride, fluorine-doped silicate glass (FSG), low-k dielectric, combinations thereof, and / or other suitable materials. The isolation features (402) may include a multilayer composition. Exemplary film deposition processes include low-pressure CVD (LPCVD), CVD, plasma-enhanced CVD (PECVD), physical vapor deposition (PVD), atomic layer deposition (ALD), thermal oxidation, e-beam evaporation, or other suitable film deposition techniques, or combinations thereof. The gate structure (404) comprises a gate dielectric layer and a gate electrode on the gate dielectric layer. In some embodiments, the gate structure (404) is a polysilicon gate providing a polysilicon electrode, and the gate dielectric layer may be silicon oxide. In some other embodiments, the gate structure (404) may be a high-k metal gate structure formed using a dummy gate structure (e.g., the poly gate discussed above) that is subsequently replaced through an alternative gate process. In some embodiments, the gate dielectric layer may comprise an interface layer and a high-k dielectric layer. The high-k gate dielectrics used and described herein comprise dielectric materials having a high dielectric constant, for example, a dielectric constant higher than that of thermal silicon oxide (~3.9). The interface layer may comprise a dielectric material such as silicon oxide, hafnium silicate, or silicon oxynitride. The interface layer may be formed using chemical oxidation, thermal oxidation, ALD, CVD, and / or other suitable methods. The high-K dielectric layer may comprise hafnium oxide, titanium oxide, hafnium zirconium oxide, tantalum oxide, hafnium silicon oxide, zirconium silicon oxide, lanthanum oxide, aluminum oxide, zirconium oxide, yttrium oxide, SrTiO3 (STO), BaTiO3 (BTO), BaZrO, hafnium lanthanum oxide, lanthanum silicon oxide, aluminum silicon oxide, hafnium tantalum oxide, hafnium titanium oxide, (Ba,Sr)TiO3 (BST), silicon nitride, silicon oxynitride, combinations thereof, or other suitable materials. The high-K dielectric layer may be formed by ALD, physical vapor deposition (PVD), CVD, oxidation, and / or other suitable methods.The gate electrode of the gate structure (404) may comprise a single layer, or alternatively, a multilayer structure such as a metal layer (work function metal layer) having a selected work function to enhance device performance, a liner layer, a wetting layer, an adhesive layer, a metal alloy, or various combinations of metal silicides. In various embodiments, the gate electrode may be formed by ALD, PVD, CVD, e-beam deposition, or other suitable processes. The gate electrode may comprise an n-type work function metal layer or a p-type work function metal layer corresponding to the function of the device. The n-type work function metal layer may comprise Ti, Al, Ag, Mn, Zr, TiAl, TiAlC, TaC, TaCN, TaSiN, TaAl, TaAlC, TiAlN, other n-type work function materials, or combinations thereof. The p-type work function metal layer comprises TiN, TaN, Ru, Mo, Al, WN, ZrSi2, MoSi2, TaSi2, NiSi2, WCN, other p-type work function materials, or combinations thereof. Gate spacers (407) may be formed along the sidewall surfaces of the gate structures (404). In some embodiments, the gate spacers (407) may comprise silicon oxide, silicon oxycarbide, silicon carbonitride, silicon nitride, zirconium oxide, aluminum oxide, or a suitable dielectric material. The gate spacers (407) may be a single-layer structure or a multi-layer structure. For embodiments in which the semiconductor structure (200) comprises GAA transistors, the GAA transistors also comprise internal spacer features (409) disposed between two adjacent nanostructures. The internal spacer features (409) may include silicon nitride, silicon oxycarbonitride, silicon carbonitride, silicon oxide, silicon oxycarbonitride, silicon carbide, or silicon oxynitride. Between the gate structures (404), NEPIs (408) and PEPIs (410) are formed on the source / drain regions of the active regions (406). Epitaxy processes suitable for forming PEPIs (410) include CVD deposition techniques [e.g., VPE (vapor-phase epitaxy) and / or UHV-CVD (ultra-high vacuum CVD)], molecular beam epitaxy (MBE), and / or other suitable processes. The epitaxial growth process may use gases and / or liquid precursors that interact with the composition of the active region (406). When forming PEPIs (410) within P-type cells (302), source / drain regions for forming NEPIs thereon may be masked. In various embodiments, PEPIs (410) may comprise Si, Ge, AlGaAs, SiGe, boron-doped SiGe (SiGeB), or other suitable materials. PEPIs (410) may comprise p-type dopants such as boron or BF2 and / or their By introducing doping species comprising suitable dopants including combinations, they can be in-situ doped during the epitaxial process. In some embodiments, an injection process may be performed to dope the PEPIs (410). A suitable epitaxial process for forming the NEPIs (408) may be similar to the epitaxial process for forming the PEPIs (410). In various embodiments, the NEPIs (408) may comprise Si, GaAs, GaAsP, SiP, or other suitable materials. The NEPIs (408) can be in-situ doped during the epitaxial process by introducing doping species comprising suitable dopants including n-type dopants such as phosphorus or arsenic and / or combinations thereof. In some embodiments, an injection process may be performed to dope the NEPIs (408).Because the source / drain regions of the active regions (406) of the blank cells (306) are not exposed during the formation of the NEPIs (408) and PEPIs (410), the source / drain features of the active regions (406) of the blank cells (306) are not reset. As a result, the blank cells (306) do not contain the NEPIs (408) or PEPIs (410). When manufacturing the semiconductor structure (200), the source / drain regions and channel regions of the blank cells (306) within the FinFET-based semiconductor structure (200) or the planar MOSFET-based semiconductor structure (200) have the same composition (e.g., silicon); Source / drain regions (described with reference to FIGS. 20a through 20c) of blank cells (306) within a GAA transistor-based semiconductor structure (200) comprise a stack of alternating first semiconductor layers (e.g., Si) and second semiconductor layers (e.g., SiGe), and each channel region of blank cells (306) within the GAA transistor-based semiconductor structure (200) comprises a plurality of nanostructures. In some embodiments, contacts are formed on one or more of the gate electrodes or source / drain features of transistors of functional P-type cells (302) or functional N-type cells (304) within a device region (204A). A dielectric structure (412) is interposed in the NEPIs (408) and PEPIs (410) as well as in the gate structure (404). In an embodiment, the dielectric structure (412) may comprise a contact etch stop layer (CESL) and an interlayer dielectric (ILD) layer on top of the CESL. The CESL may comprise silicon nitride, silicon oxide, silicon oxynitride, and / or other materials known in the art, and may be formed by ALD, a plasma-enhanced chemical vapor deposition (PECVD) process, and / or other suitable film deposition or oxidation processes. In some embodiments, the ILD layer comprises tetraethylorthosilicate (TEOS) oxide, undoped silicate glass, or doped silicon oxide, such as borophosphosilicate glass (BPSG), fused silica glass (FSG), phosphosilicate glass (PSG), boron-doped silicon glass (BSG), and / or other suitable dielectric materials. The ILD layer can be formed by a PECVD process or other suitable film formation technology. Since the source / drain region of the active region (406) within the blank cell (306) is not reset, as illustrated in FIGS. 4b and 4d, the dielectric structure (412) is also placed over the active region (406) and in direct contact with the active region (406). In the embodiment described in FIG. 3a, the cells of the sub-region (204) [i.e., P-type cells (302), N-type cells (304), and blank cells (306)] are arranged in a 12 x 12 (column x row) array, the number of N1 of the functional N-type cells (304) is 16, the number of P1 of the functional P-type cells (302) is 32, the number of N2 of the dummy N-type cells (304) is 40, the number of P2 of the dummy P-type cells (302) is 24, the number of M of the blank cells (306) is 32, and in the top view, the blank cells (306) surround the device region (204A). In other alternative embodiments, such as those illustrated in FIGS. 5a through 5e and FIGS. 6a through 6f, for sub-regions (204) having the same device region (204A), the configuration of the dummy region (204B) can be flexibly adjusted to provide similar advantages described above. Layout views and cross-sectional views of the P-type cell (302), N-type cell (304), and blank cells (306) in subsequent embodiments are substantially the same as those described with reference to FIG. 3b and FIGS. 4a through 4e, and repetitive descriptions are omitted for simplification. FIGS. 5a through 5e illustrate an embodiment in which each of the sub-regions (500A-500E) has a number of M blank cells (306) different from that of the sub-region (204) [and accordingly a percentage of the blank cells (306) of the sub-region (204)], and the dummy N-type cells (304) provide isolation between the device region (204A) and the dummy P-type cells (302). More specifically, FIG. 5a illustrates a partial top view of a sub-region (500A) including the device region (204A) described above and a dummy region (204B1) surrounding the device region (204A). Dummy region (204B1) is similar to the dummy region (204B) described above, and two major differences between dummy region (204B1) and dummy region (204B) include that dummy region (204B1) does not contain the blank cells (306) described above, and that the number of N2 of dummy N-type cells (304) and the number of P2 of dummy P-type cells (302) are different from the number of dummy region (204B) illustrated by FIG. 3a. For example, in this illustrated embodiment, the number of N1 of functional N-type cells (304) is 16, the number of P1 of functional P-type cells (302) is 32, the number of N2 of dummy N-type cells (304) is 56, the number of P2 of dummy P-type cells (302) is 40, and the number of M of blank cells (306) is 0. Thus, the total number of N-type cells (i.e., N1+N2) is 72, the total number of P-type cells (i.e., P1+P2) is 72, and the percentage of the number of M blank cells (306) relative to the total number of cells in the sub-region (500A) is 0. FIG. 5b illustrates a partial top view of a sub-region (500B) comprising the device region (204A) described above and a dummy region (204B2) surrounding the device region (204A). The sub-region (500B) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B2) is similar to the dummy region (204B) described above, and two major differences between the dummy region (204B2) and the dummy region (204B) include that the dummy region (204B2) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (500B) is about 15%. For the sub-region (500B) having a 12 x 12 (column x row) array as shown in FIG. 5b, the number of N1 functional N-type cells (304) is 16, the number of P1 functional P-type cells (302) is 32, the number of N2 dummy N-type cells (304) is 46, the number of P2 dummy P-type cells (302) is 30, and the number of M blank cells (306) is 20. Thus, the total number of N-type cells (i.e., N1+N2) is 62, and the total number of P-type cells (i.e., P1+P2) is 62. FIG. 5c illustrates a partial top view of a sub-region (500C) comprising the device region (204A) described above and a dummy region (204B3) surrounding the device region (204A). The sub-region (500C) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B3) is similar to the dummy region (204B) described above, and two major differences between the dummy region (204B3) and the dummy region (204B) include that the dummy region (204B3) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (500C) is about 20%. For the sub-region (500C) having a 12 x 12 (column x row) array as shown in FIG. 5c, the number of N1 functional N-type cells (304) is 16, the number of P1 functional P-type cells (302) is 32, the number of N2 dummy N-type cells (304) is 42, the number of P2 dummy P-type cells (302) is 26, and the number of M blank cells (306) is 28. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 58. Each of the dummy P-type cells (302) is separated from the device area (204A) by either the dummy N-type cells (304) or the blank cells (306). FIG. 5d illustrates a partial top view of a sub-region (500D) comprising the device region (204A) described above and a dummy region (204B4) surrounding the device region (204A). The sub-region (500D) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B4) is similar to the dummy region (204B) described above, and two major differences between the dummy region (204B4) and the dummy region (204B) include that the dummy region (204B4) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (500D) is about 30%. For the sub-region (500D) having a 12 x 12 (column x row) array as shown in FIG. 5d, the number of functional N-type cells (304) N1 is 16, the number of functional P-type cells (302) P1 is 32, the number of dummy N-type cells (304) N2 is 36, the number of dummy P-type cells (302) P2 is 20, and the number of blank cells (306) M is 40. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 52. FIG. 5e illustrates a partial top view of a sub-region (500E) comprising the device region (204A) described above and a dummy region (204B5) surrounding the device region (204A). The sub-region (500E) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B5) is similar to the dummy region (204B) described above, and two major differences between the dummy region (204B5) and the dummy region (204B) include that the dummy region (204B5) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (500D) is about 45%. For the sub-region (500E) having a 12 x 12 (column x row) array as shown in FIG. 5e, the number of functional N-type cells (304) N1 is 16, the number of functional P-type cells (302) P1 is 32, the number of dummy N-type cells (304) N2 is 25, the number of dummy P-type cells (302) P2 is 9, and the number of blank cells (306) M is 62. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 41. In the embodiments described above with reference to FIGS. 3a and FIGS. 5a through 5e, all dummy N-type cells (304) are positioned immediately adjacent to the device area (204A) or the blank cells (306) so that the dummy P-type cells (302) are separated from the device area (204A). In some other alternative embodiments, the dummy P-type cells (302) and the dummy N-type cells (304) may each be positioned randomly. For example, FIGS. 6a through 6f each illustrates a partial top view of a sub-area (600A / 600B / 600C / 600D / 600E / 600F) comprising the device area (204A) described above and a corresponding dummy area (204B6 / 204B7 / 204B8 / 204B9 / 204B10 / 204B11) surrounding the device area (204A). The top view and cross-sectional view of the device area (204A), P-type cell (302), N-type cell (304), and blank cell (306) have been described above, and a repetitive description is omitted for simplification. The dummy P-type cells (302) and dummy N-type cells (304) within the dummy areas (204B6 / 204B7 / 204B8 / 204B9 / 204B10 / 204B11) are randomly arranged, and each of the dummy areas (204B6 / 204B7 / 204B8 / 204B9 / 204B10 / 204B11) has blank cells (306) of different percentages. More specifically, FIG. 6a illustrates a partial top view of a sub-region (600A) comprising the device region (204A) described above with reference to FIG. 3a and a dummy region (204B6) surrounding the device region (204A). The sub-region (600A) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B11) is similar to the dummy region (204B) described above, and the main difference between the dummy region (204B6) and the dummy region (204B) is that the dummy region (204B6) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302), and the dummy N-type cells (304) and dummy P-type cells (302) are randomly placed within the dummy region (204B) of the sub-region (600A). For example, in this illustrated embodiment, the number of N1 of the functional N-type cells (304) is 16, the number of P1 of the functional P-type cells (302) is 32, the number of N2 of the dummy N-type cells (304) is 56, the number of P2 of the dummy P-type cells (302) is 40, and the number of M of the blank cells (306) is 0. Thus, the total number of N-type cells (i.e., N1+N2) is 72, the total number of P-type cells (i.e., P1+P2) is 72, and the percentage of the number of M of the blank cells (306) relative to the total number of cells within the sub-region (600A) is 0. Each of the dummy P-type cells (302) may be placed immediately adjacent to the device area (204A) or placed far from the device area (204A). Likewise, each of the dummy N type cells (304) can be placed immediately adjacent to the device area (204A) or placed far from the device area (204A). FIG. 6b illustrates a partial top view of a sub-region (600B) comprising the device region (204A) described above and a dummy region (204B7) surrounding the device region (204A). The sub-region (600B) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B7) is similar to the dummy region (204B6) described above, and the difference between the dummy region (204B2) and the dummy region (204B7) is that the dummy region (204B7) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (600B) is about 15%. For the sub-region (600B) having a 12 x 12 (column x row) array as shown in FIG. 6b, the number of N1 functional N-type cells (304) is 16, the number of P1 functional P-type cells (302) is 32, the number of N2 dummy N-type cells (304) is 46, the number of P2 dummy P-type cells (302) is 30, and the number of M blank cells (306) is 20. Thus, the total number of N-type cells (i.e., N1+N2) is 62, and the total number of P-type cells (i.e., P1+P2) is 62. Each of the blank cells (306) is positioned immediately adjacent to the device area (204A). Each of the dummy P-type cells (302) may be positioned immediately adjacent to the device area (204A) or the blank cells (306). Each of the dummy P-type cells (302) may also be positioned away from the device area (204A). Similarly, each of the dummy N-type cells (304) may be positioned immediately adjacent to the device area (204A) or the blank cells (306), or each of the dummy N-type cells (304) may be positioned away from the device area (204A). FIG. 6c illustrates a partial top view of a sub-region (600C) comprising the device region (204A) described above and a dummy region (204B8) surrounding the device region (204A). The sub-region (600C) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B8) is similar to the dummy region (204B6) described above, and the main difference between the dummy region (204B8) and the dummy region (204B) is that the dummy region (204B8) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (600C) is about 20%. For the sub-region (600C) having a 12 x 12 (column x row) array as shown in FIG. 6c, the number of N1 functional N-type cells (304) is 16, the number of P1 functional P-type cells (302) is 32, the number of N2 dummy N-type cells (304) is 42, the number of P2 dummy P-type cells (302) is 26, and the number of M blank cells (306) is 28. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 58. The blank cells (306) are placed immediately adjacent to the device area (204A). Each of the dummy P-type cells (302) can be separated from the blank cells (306) by the dummy N-type cells (304) or placed immediately adjacent to the blank cells (306). Each of the dummy N-type cells (304) can be separated from the blank cells (306) by the dummy P-type cells (302) or placed immediately adjacent to the blank cells (306). FIG. 6d illustrates a partial top view of a sub-region (600D) comprising the device region (204A) described above and a dummy region (204B9) surrounding the device region (204A). The sub-region (600D) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B9) is similar to the dummy region (204B6) described above, and the main difference between the dummy region (204B9) and the dummy region (204B) is that the dummy region (204B9) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (600D) is about 22%. For the sub-region (600D) having a 12 x 12 (column x row) array as shown in FIG. 6d, the number of N1 functional N-type cells (304) is 16, the number of P1 functional P-type cells (302) is 32, the number of N2 dummy N-type cells (304) is 40, the number of P2 dummy P-type cells (302) is 24, and the number of M blank cells (306) is 32. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 56. The blank cells (306) are placed immediately adjacent to the device area (204A). Each of the dummy P-type cells (302) can be separated from the blank cells (306) by the dummy N-type cells (304) or placed immediately adjacent to the blank cells (306). Each of the dummy N-type cells (304) can be separated from the blank cells (306) by the dummy P-type cells (302) or placed immediately adjacent to the blank cells (306). FIG. 6e illustrates a partial top view of a sub-region (600E) comprising the device region (204A) described above and a dummy region (204B10) surrounding the device region (204A). The sub-region (600E) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B10) is similar to the dummy region (204B6) described above, and the main difference between the dummy region (204B10) and the dummy region (204B) is that the dummy region (204B10) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (600E) is about 30%. For the sub-region (600E) having a 12 x 12 (column x row) array as shown in FIG. 6e, the number of functional N-type cells (304) N1 is 16, the number of functional P-type cells (302) P1 is 32, the number of dummy N-type cells (304) N2 is 36, the number of dummy P-type cells (302) P2 is 20, and the number of blank cells (306) M is 40. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 52. The blank cells (306) are placed immediately adjacent to the device area (204A). Each of the dummy P-type cells (302) can be separated from the blank cells (306) by the dummy N-type cells (304) or placed immediately adjacent to the blank cells (306). Each of the dummy N-type cells (304) can be separated from the blank cells (306) by the dummy P-type cells (302) or placed immediately adjacent to the blank cells (306). FIG. 6f illustrates a partial top view of a sub-region (600F) comprising the device region (204A) described above and a dummy region (204B11) surrounding the device region (204A). The sub-region (600F) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B11) is similar to the dummy region (204B6) described above, and the main difference between the dummy region (204B11) and the dummy region (204B) is that the dummy region (204B11) has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (600F) is about 45%. For the sub-region (600F) having a 12 x 12 (column x row) array as shown in FIG. 6f, the number of N1 functional N-type cells (304) is 16, the number of P1 functional P-type cells (302) is 32, the number of N2 dummy N-type cells (304) is 25, the number of P2 dummy P-type cells (302) is 9, and the number of M blank cells (306) is 62. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 41. The blank cells (306) are placed immediately adjacent to the device area (204A). Each of the dummy P-type cells (302) can be separated from the blank cells (306) by the dummy N-type cells (304) or placed immediately adjacent to the blank cells (306). Each of the dummy N-type cells (304) can be separated from the blank cells (306) by the dummy P-type cells (302) or placed immediately adjacent to the blank cells (306). In the embodiments described with reference to FIGS. 3a, FIGS. 5a through 5e and FIGS. 6a through 6f, the device region (204A) has P1 number of functional P-type cells (302) and N1 number of functional N-type cells (304), and N1 is less than P1. In some other embodiments, N1 number of functional N-type cells (304) is greater than P1 number of functional P-type cells (302), and N2 number of dummy N-type cells (304) is less than P2 number of dummy P-type cells (302), so that the total number of N-type cells (i.e., N1+N2) is equal to the total number of P-type cells (304) (i.e., P1+P2). FIGS. 7a through 7f and FIGS. 8a through 8f illustrate these embodiments. More specifically, for the embodiments illustrated in FIGS. 7a through 7f, the sub-region includes a device region (204A') having more functional N-type cells (304) than functional P-type cells (302), and dummy P-type cells (302) are disposed immediately adjacent to the device region (204A') or immediately adjacent to blank cells (306). For the embodiments illustrated in FIGS. 8a through 8f, the sub-region includes a device region (204A') having more functional N-type cells (304) than functional P-type cells (302), and dummy P-type cells (302) and dummy N-type cells (304) may be disposed randomly within the dummy region. FIG. 7a illustrates a partial top view of a sub-region (700A) comprising a device area (204A') and a dummy area (204B1') surrounding the device area (204A'). The sub-region (700A) has an equal number of P-type cells (302) and N-type cells (304). In an embodiment, in the device area (204A'), the ratio of the number of functional N-type cells (304) N1 to the number of functional P-type cells (302) P1 is approximately 2:1. The positional arrangement of the functional P-type cells (302) and functional N-type cells (304) in the device area (204A') is merely illustrative and is not intended to be limiting. The dummy area (204B1') includes dummy N-type cells (304) and dummy P-type cells (302) and does not include blank cells (306). The ratio of the number of dummy P-type cells (302) P2 to the number of dummy N-type cells (304) N2 is less than 2, and the dummy P-type cells (302) are placed immediately adjacent to the device area (204A') to reduce device defects, and the dummy N-type cells (304) are separated from the device area (204A') by the dummy P-type cells (302). In this illustrated embodiment, the cells of the sub-area (700A) [i.e., P-type cells (302), N-type cells (304), and blank cells (306)] are arranged in a 12 x 12 (column x row) array, the number of N1 is 32, and the number of P1 is 16. The number of N2 is 40, and the number of P2 is 56. In this way, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 72. FIG. 7b illustrates a partial top view of a sub-region (700B) comprising the device region (204A') described above and a dummy region (204B2') surrounding the device region (204A'). The sub-region (700B) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B2') is similar to the dummy region (204B1') described above, and the difference between the dummy region (204B2') and the dummy region (204B1') is that the dummy region (204B2') has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (700B) is about 15%. For the sub-region (700B) having a 12 x 12 (column x row) array as shown in FIG. 7b, the number of functional P-type cells (302) P1 is 16, the number of functional N-type cells (304) N1 is 32, the number of dummy P-type cells (302) P2 is 46, the number of dummy N-type cells (304) N2 is 30, and the number of blank cells (306) M is 20. Thus, the total number of N-type cells (i.e., N1+N2) is 62, and the total number of P-type cells (i.e., P1+P2) is 62. Each of the blank cells (306) is positioned immediately adjacent to the device area (204A'). Each of the dummy P-type cells (302) is positioned immediately adjacent to the device area (204A') or immediately adjacent to the blank cells (306). The dummy N-type cells (304) are spaced from the device area (204A') by the blank cells (306) or the dummy P-type cells (302). FIG. 7c illustrates a partial top view of a sub-region (700C) comprising the device region (204A') described above and a dummy region (204B3') surrounding the device region (204A'). The sub-region (700C) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B3') is similar to the dummy region (204B1') described above, and the difference between the dummy region (204B3') and the dummy region (204B1') is that the dummy region (204B3') has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (700C) is about 20%. For the sub-region (700C) having a 12 x 12 (column x row) array as shown in FIG. 7c, the number of functional N-type cells (304) N1 is 32, the number of functional P-type cells (302) P1 is 16, the number of dummy N-type cells (304) N2 is 26, the number of dummy P-type cells (302) P2 is 42, and the number of blank cells (306) M is 28. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 58. Each of the blank cells (306) is placed immediately adjacent to the device area (204A'). Each of the dummy N-type cells (304) is separated from the device area (204A') by the dummy P-type cells (302) and the blank cells (306). FIG. 7d illustrates a partial top view of a sub-region (700D) comprising the device region (204A') described above and a dummy region (204B4') surrounding the device region (204A'). The sub-region (700D) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B4') is similar to the dummy region (204B1') described above, and the difference between the dummy region (204B4') and the dummy region (204B1') is that the dummy region (204B4') has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (700D) is about 22%. For the sub-region (700D) having a 12 x 12 (column x row) array as shown in FIG. 7d, the number of N1 functional N-type cells (304) is 32, the number of P1 functional P-type cells (302) is 16, the number of N2 dummy N-type cells (304) is 24, the number of P2 dummy P-type cells (302) is 40, and the number of M blank cells (306) is 32. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 56. Each of the blank cells (306) is placed immediately adjacent to the device area (204A'). Each of the dummy N-type cells (304) is separated from the device area (204A') by the dummy P-type cells (302) and the blank cells (306). FIG. 7e illustrates a partial top view of a sub-region (700E) comprising the device region (204A') described above and a dummy region (204B5') surrounding the device region (204A'). The sub-region (700E) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B5') is similar to the dummy region (204B1') described above, and the difference between the dummy region (204B5') and the dummy region (204B1') is that the dummy region (204B5') has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (500D) is about 30%. For the sub-region (700E) having a 12 x 12 (column x row) array as shown in FIG. 7e, the number of functional N-type cells (304) N1 is 32, the number of functional P-type cells (302) P1 is 16, the number of dummy N-type cells (304) N2 is 20, the number of dummy P-type cells (302) P2 is 36, and the number of blank cells (306) M is 40. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 52. The blank cells (306) are placed immediately adjacent to the device area (204A'). Each of the dummy N-type cells (304) is separated from the device area (204A') by the dummy P-type cells (302) and the blank cells (306). FIG. 7f illustrates a partial top view of a sub-region (700F) comprising the device region (204A') described above and a dummy region (204B6') surrounding the device region (204A'). The sub-region (700F) has an equal number of P-type cells (302) and N-type cells (304). The dummy region (204B6') is similar to the dummy region (204B1') described above, and the difference between the dummy region (204B6') and the dummy region (204B1') is that the dummy region (204B6') has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in this illustrated embodiment, the ratio of the number of blank cells (306) M to the total number of cells (e.g., 302, 304, 306) of the sub-region (500D) is about 45%. For the sub-region (700F) having a 12 x 12 (column x row) array as shown in FIG. 7f, the number of functional N-type cells (304) N1 is 32, the number of functional P-type cells (302) P1 is 16, the number of dummy N-type cells (304) N2 is 9, the number of dummy P-type cells (302) P2 is 25, and the number of blank cells (306) M is 62. Thus, the total number of N-type cells (i.e., N1+N2) and the total number of P-type cells (i.e., P1+P2) are each 41. The blank cells (306) are placed immediately adjacent to the device area (204A'). Each of the dummy N-type cells (304) is separated from the device area (204A') by the dummy P-type cells (302) and the blank cells (306). In the embodiments described with reference to FIGS. 7a through 7f, all dummy P-type cells (302) are positioned immediately adjacent to the device area (204A) or the blank cells (306) so that the dummy N-type cells (304) are separated from the device area (204A). In some other alternative embodiments, the dummy P-type cells (302) and the dummy N-type cells (304) may each be positioned randomly. For example, FIGS. 8a through 8f each illustrate a partial top view of a sub-region (800A / 800B / 800C / 800D / 800E / 800F) comprising the device region (204A') described above and the corresponding dummy region (204B7' / 204B8' / 204B9' / 204B10' / 204B11' / 204B12') surrounding the device region (204A'). The top view and cross-sectional view of the device region (204A') and the P-type cell (302), N-type cell (304), and blank cell (306) have been described above, and a repetitive description is omitted for simplification. The dummy P type cells (302) and dummy N type cells (304) within the dummy area (204B7' / 204B8' / 204B9' / 204B10' / 204B11' / 204B12') are randomly arranged, and each of the dummy area (204B7' / 204B8' / 204B9' / 204B10' / 204B11' / 204B12') has blank cells (306) of different percentages. More specifically, FIG. 8a illustrates a partial top view of a sub-region (800A) including the device area (204A') described above and a dummy area (204B7') surrounding the device area (204A'). FIG. 8b illustrates a partial top view of a sub-region (800B) including the device area (204A') described above and a dummy area (204B8') surrounding the device area (204A'). FIG. 8c illustrates a partial top view of a sub-region (800C) including the device area (204A') described above and a dummy area (204B9') surrounding the device area (204A'). FIG. 8d illustrates a partial top view of a sub-region (800D) including the device area (204A') described above and a dummy area (204B9') surrounding the device area (204A'). FIG. 8e illustrates a partial top view of a sub-region (800E) including the device area (204A') described above and a dummy area (204B10') surrounding the device area (204A'). FIG. 8f illustrates a partial top view of a sub-region (800F) including the device area (204A') described above and a dummy area (204B11') surrounding the device area (204A'). Each of the sub-regions (800A, 800B, 800C, 800D, 800E, 800F) has a corresponding number of P-type cells (302) and N-type cells (304). The dummy region (204B7' / 204B8' / 204B9' / 204B10' / 204B11' / 204B12') is similar to the dummy region (204B1') described above, and the main difference between the dummy region (204B7' / 204B8' / 204B9' / 204B10' / 204B11' / 204B12') and the dummy region (204B1') is that the dummy region () has a different number of blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302), and the dummy N-type cells (304) and dummy P-type cells (302) are the dummy cells of the corresponding sub-regions (800A, 800B, 800C, 800D, 800E, 800F). It includes being randomly placed within the area (204B). For example, in the illustrated embodiments, the ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-area (800A) is 0; the ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-area (800B) is about 15%; and the ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-area (800C) is about 20%; The ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-region (800D) is about 22%; the ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-region (800E) is about 30%; and the ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-region (800F) is about 45%.Each of the dummy P-type cells (302) within the sub-region (800A / 800B / 800C / 800D / 800E / 800F) may be placed immediately adjacent to the device area (204A') or placed far away from the device area (204A'). Likewise, each of the dummy N-type cells (304) may be placed immediately adjacent to the device area (204A') or placed far away from the device area (204A'). In the exemplified embodiments, for the sub-regions (800A, 800B, 800C, 800D, 800E, 800F) having a 12 x 12 (column x row) array as depicted in FIGS. 8a through 8f, the number N1 of functional N-type cells (304) is 32, and the number P1 of functional P-type cells (302) is 16. Within the sub-region (800A), the number N2 of dummy N-type cells (304) within the sub-region (800A) is 40, the number P2 of dummy P-type cells (302) within the sub-region (800A) is 56, and the number M of blank cells (306) is 0. In the sub-region (800B), the number N2 of dummy N-type cells (304) in the sub-region (800B) is 30, the number P2 of dummy P-type cells (302) in the sub-region (800B) is 46, and the number M of blank cells (306) is 20. In the sub-region (800C), the number N2 of dummy N-type cells (304) in the sub-region (800C) is 26, the number P2 of dummy P-type cells (302) in the sub-region (800C) is 42, and the number M of blank cells (306) is 28. In the sub-region (800D), the number of dummy N-type cells (304) in the sub-region (800D) is 24, the number of dummy P-type cells (302) in the sub-region (800D) is 40, and the number of blank cells (306) is 32. In the sub-region (800E), the number of dummy N-type cells (304) in the sub-region (800E) is 20, the number of dummy P-type cells (302) in the sub-region (800E) is 36, and the number of blank cells (306) is 40. In the sub-region (800F), the number of dummy N-type cells (304) in the sub-region (800F) is N2, the number of dummy P-type cells (302) in the sub-region (800F) is P2, and the number of blank cells (306) is M, which is 62. In the embodiments described with reference to FIGS. 3a through 6f, the number of N1 is smaller than the number of P1, and in the embodiments described with reference to FIGS. 7a through 8f, the number of N1 is larger than the number of P1. In some other embodiments, the number of N1 of the functional N-type cells (304) is equal to the number of P1 of the functional P-type cells (302), and the number of N2 of the dummy N-type cells (304) is equal to the number of P2 of the dummy P-type cells (302), and accordingly, the total number of N-type cells (304) (i.e., N1+N2) is equal to the total number of P-type cells (304) (i.e., P1+P2). FIGS. 9a through 9f illustrate these embodiments. For the embodiments illustrated by FIGS. 9a through 9f, each sub-region (900A / 900B / 900C / 900D / 900E / 900F) comprises a device region (204A) having an equal number of functional N-type cells (304) and functional P-type cells (302), and a corresponding dummy region (204B1" / 204B2" / 204B3" / 204B4" / 204B5" / 204B6") having an equal number of dummy N-type cells (304) and dummy P-type cells (302), each having a different percentage of blank cells (306) surrounding the device region (204A). The dummy P-type cells (302) and dummy N-type cells (304) may be randomly placed within the corresponding dummy region. That is, each of the dummy P-type cells (302) and dummy N-type cells (304) can be placed immediately adjacent to the device area (204A) or immediately adjacent to the blank cells (306). The top view and cross-sectional view of the P-type cell (302), N-type cell (304), and blank cell (306) have been described above, and a repetitive description is omitted for simplification. Each of the sub-regions (900A, 900B, 900C, 900D, 900E, 900F) has a corresponding number of P-type cells (302) and N-type cells (304). Each of the dummy regions (204B1" / 204B2" / 204B3" / 204B4" / 204B5" / 204B6") has a different number of M blank cells (306), and accordingly has a different number of dummy N-type cells (304) and dummy P-type cells (302). For example, in the illustrated embodiments, the ratio of the number of M blank cells (306) to the total number of cells (e.g., 302, 304, 306) of the sub-region (900A) is 0; The ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-region (900B) is approximately 15%; the ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-region (900C) is approximately 20%; the ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-region (900D) is approximately 22%; and the ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-region (900E) is approximately 30%; The ratio of the number of blank cells (306) to the total number of cells (e.g., 302, 304, 306) in the sub-region (900F) is approximately 45%. Each of the dummy P type cells (302) in the sub-region (900A / 900B / 900C / 900D / 900E / 900F) can be placed immediately adjacent to the device area (204A) or placed far away from the device area (204A). Likewise, each of the dummy N type cells (304) can be placed immediately adjacent to the device area (204A') or placed far away from the device area (204A). In the exemplified embodiments, for the sub-regions (900A, 900B, 900C, 900D, 900E, 900F) having a 12 x 12 (column x row) array as depicted in FIGS. 9a through 9f, the number N1 of functional N-type cells (304) is 24, and the number P1 of functional P-type cells (302) is 24. Within sub-region (900A), the number N2 of dummy N-type cells (304) within sub-region (800A) is 48, the number P2 of dummy P-type cells (302) within sub-region (800A) is 48, and the number M of blank cells (306) is 0. In the sub-region (900B), the number N2 of dummy N-type cells (304) in the sub-region (800B) is 38, the number P2 of dummy P-type cells (302) in the sub-region (800B) is 38, and the number M of blank cells (306) is 20. In the sub-region (900C), the number N2 of dummy N-type cells (304) in the sub-region (800C) is 34, the number P2 of dummy P-type cells (302) in the sub-region (800C) is 34, and the number M of blank cells (306) is 28. In the sub-region (900D), the number of dummy N-type cells (304) in the sub-region (800D) is 32, the number of dummy P-type cells (302) in the sub-region (800D) is 32, and the number of blank cells (306) is 32. In the sub-region (900E), the number of dummy N-type cells (304) in the sub-region (900E) is 28, the number of dummy P-type cells (302) in the sub-region (800E) is 28, and the number of blank cells (306) is 40. In the sub-region (900F), the number of dummy N-type cells (304) in the sub-region (800E) is 17, the number of dummy P-type cells (302) in the sub-region (800E) is 17, and the number of blank cells (306) is 62. In the embodiments described above with reference to FIGS. 3a through 9f, the cells of the sub-regions (i.e., P-type cells (302), N-type cells (304), and blank cells (306)) are arranged in a 12 x 12 (column x row) array. In some other embodiments, the cells of the sub-regions (i.e., P-type cells (302), N-type cells (304), and blank cells (306)) may have other arrangements. For example, FIGS. 10a through 10c illustrate sub-regions (1000A, 1000B, 1000C) having cells arranged in a 10 x 10 (column x row) array. Differences between the sub-regions (1000A, 1000B, 1000C) and the aforementioned sub-regions are reflected in the drawings, and repeated descriptions are omitted for the sake of simplification. In the embodiments described above with reference to FIGS. 2b through 10c, in the top view, a dummy region (e.g., 204B) surrounds a device region (e.g., 204A). In some other alternative embodiments, the dummy region may be positioned laterally adjacent to the device region. For example, FIG. 11 illustrates a sub-region (1100) comprising a device region (204A"') and a dummy region (204B"') laterally adjacent to the device region (204A"'). The total number of N-type cells (304) in the sub-region (1100) is equal to the total number of P-type cells (302) in the sub-region (1100). In the illustrated embodiment, within the sub-region (1100), the number of P1 of functional P-type cells (302) is greater than the number of N1 of functional N-type cells (304), and the number of P2 of dummy P-type cells (302) is less than the number of N2 of dummy N-type cells (304). In another embodiment, within the sub-region (1100), the number of P1 of functional P-type cells (302) is less than the number of N1 of functional N-type cells (304), and the dummy P-type The number of P2 cells (302) is greater than the number of N2 dummy N-type cells (304). In another embodiment, within the sub-region (1100), the number of P1 functional P-type cells (302) is equal to the number of N1 functional N-type cells (304), and the number of P2 dummy P-type cells (302) is equal to the number of N2 dummy N-type cells (304). The ratio of the number of blank cells (306) M in the dummy area of ​​the sub-region (1100) to the total number of the sub-region (1100) (i.e., N1+N2+P1+P2) is within the range of about 0 to about 45% in a manner similar to the embodiments described above with reference to FIGS. 3a through 10c. An alternative embodiment illustrated by FIG. 11 is applicable to the embodiments described above with reference to FIGS. 3a through 10c. In the embodiments described above with reference to FIGS. 2b through 11, where sub-regions (e.g., 204) contain blank cells (306), the blank cells (306) within the dummy region (e.g., 204B) are positioned immediately adjacent to the device region (e.g., 204A). In some other alternative embodiments, the blank cells (306) may also be positioned randomly. For example, the blank cells (306) within the sub-region (1200) illustrated by FIG. 12 are positioned between the dummy N-type cells (304) and the dummy P-type cells (302). Other positions are also possible. The alternative embodiment illustrated by FIG. 12 is applicable to the embodiments described above with reference to FIGS. 3a through 11. FIG. 13 illustrates a method (1300) that can be implemented to form a semiconductor structure [e.g., a semiconductor structure (200)]. In an embodiment, the semiconductor structure is a chip, in particular an integrated circuit (IC) chip. The method (1300) may be implemented after a layout for the semiconductor structure (1400) has been determined, as discussed above in relation to the method (100) of FIG. 1. The method (1300) is merely illustrative and is not intended to limit the disclosure to what is explicitly illustrated herein. Additional steps may be provided before, during, and after the method (1300), and some of the steps described may be replaced, deleted, or moved for additional embodiments of the method. For the sake of brevity, not all steps are described in detail herein. FIG. 13 is described together with FIG. 3b and with FIG. 14a through 20a, FIG. 14b through 20b, and FIG. 14c through 20c below. FIGS. 14a to 20a illustrate partial cross-sectional views of a portion of a semiconductor structure [e.g., an N-type transistor in an N-type cell (304)] taken along line C-C' as shown in FIG. 3b during multiple manufacturing stages of the method of FIG. 13, FIGS. 14b to 20b illustrate partial cross-sectional views of a portion of a semiconductor structure [e.g., a dummy feature in a blank cell (306)] taken along line D-D' as shown in FIG. 3b during multiple manufacturing stages of the method of FIG. 13, FIGS. 14c to 20c illustrate partial cross-sectional views of a portion of a semiconductor structure [e.g., a P-type transistor in a P-type cell (302)] taken along line EE as shown in FIG. 3b during multiple manufacturing stages of the method of FIG. 13. Referring to FIGS. 13 and FIGS. 14a through 14c, the method (1300) comprises a block 1302 in which active regions (406) are formed on a substrate (e.g., substrate (201)). In an embodiment, as described above with reference to FIGS. 4a through 4e, each of the active regions (406) comprises a pin having a uniform composition (e.g., silicon) in the Z direction. In this illustrated embodiment, each of the active regions (406) comprises a vertical stack of alternating channel layers (406a) interleaved by sacrificial layers (406b) of the upper portion of the substrate (201). Each channel layer (406a) may comprise a semiconductor material such as silicon, germanium, silicon carbide, silicon germanium, GeSn, SiGeSn, SiGeCSn, other suitable semiconductor materials, or a combination thereof, but each sacrificial layer (406b) has a composition different from that of the channel layer (406a). In an embodiment, the channel layer (406a) comprises silicon (Si), and the sacrificial layer (406b) comprises silicon germanium (SiGe). The channel layers (406a) and the sacrificial layers (406b) may be epitaxially deposited on a substrate (201) using molecular beam epitaxy (MBE), vapor-phase epitaxy (VPE), ultra-high vacuum CVD (UHV-CVD), and / or other suitable epitaxial growth processes. In some embodiments, each active region (406) may comprise a total of 3 to 10 pairs of alternating sacrificial layers (406b) and channel layers (406a), and of course, other configurations may also be applied depending on specific design requirements. Two adjacent active regions (406) may be isolated by an isolation feature [e.g., shallow trench isolation (STI) or field oxide (FOX)]. Referring to FIG. 13 and FIG. 15a through 15c, the method (1300) comprises a block 1304 in which gate stacks (1402) are formed on active regions (406). Each gate stack (1402) may include a dummy dielectric layer (e.g., silicon oxide) and a dummy gate electrode (e.g., polysilicon) disposed on the dummy dielectric layer. The gate stack (1402) may also include a gate-top hard mask layer (e.g., SiN) on the dummy gate electrode. A gate spacer (407) is formed to extend along the sidewalls of the dummy gate electrode (1402). The gate stack (1402) may be replaced by a gate structure (404) in a subsequent manufacturing process. Referring to FIG. 13 and FIG. 16a through 16c, the method (1300) comprises a block 1306 in which a first mask layer (1404) is formed on a substrate (201) and patterned using a first masking element to form an opening (1406N) that exposes the source / drain region of an N-type cell (304). The first masking element may be designed during the layout design process described with reference to FIG. 1. The first mask layer (1404) may be patterned using a combination of lithography and etching steps. While using the patterned first mask layer (1404) as an etching mask, an etching process is performed to recess the source / drain regions of the active regions (406) of the N-type cells (304) to form the openings (1406N). The number of openings (1406N) is a function of the open ratio of the first masking element. As illustrated in FIGS. 16b through 16c, the source / drain regions of the P-type cell (302) and the blank cells (306) are covered by the patterned first mask layer (1404). Referring to FIG. 13 and FIG. 17a through 17c, the method (1300) comprises a block 1308 in which NEPIs (408) of N-type cells (304) are formed within an opening (1406N). After forming the openings (1406N), inner spacer features (409) are formed between two adjacent channel layers (406a) and in direct contact with sacrificial layers (406b) within the channel regions of the N-type cells (304). The inner spacer features (409) may include silicon nitride, silicon oxycarbonitride, silicon carbonitride, silicon oxide, silicon oxycarbonitride, silicon carbide, or silicon oxynitride. Then, NEPIs (408) are formed within the opening (1406N). Exemplary NEPIs (408) may comprise silicon, phosphorus-doped silicon, arsenic-doped silicon, antimony-doped silicon, or other suitable materials, and may be doped in situ during an epitaxial process by introducing an n-type dopant such as phosphorus, arsenic, or antimony, or may be doped ex situ using a bonding injection process. The patterned first mask layer (1404) may be optionally removed after the formation of the NEPIs (408). Referring to FIG. 13 and FIG. 16a through 16c, the method (1300) comprises a block 1310 in which a second mask layer (1408) is formed on a substrate and patterned using a second masking element to form openings (1406P) that expose source / drain regions of P-type cells (302). The second masking element may be designed during the layout design process described with reference to FIG. 1. The second mask layer (1408) may be patterned using a combination of lithography and etching steps. While using the patterned second mask layer (1408) as an etching mask, an etching process is performed to recess the source / drain regions of the active regions (406) of the P-type cells (302) to form openings (1406P). The number of openings (1406P) is a function of the open ratio of the second masking element. As illustrated in FIGS. 18b through 18c, the source / drain regions of the NEPIs (408) and the blank cell (306) are covered by the patterned second mask layer (1408). Referring to FIG. 13 and FIG. 19a through 19c, the method (1300) comprises a block 1312 in which PEPIs (410) of P-type cells (302) are formed within an opening (1406P). After forming the openings (1406P), inner spacer features (409) are formed between two adjacent channel layers (406a) and in direct contact with sacrificial layers (406b) within the channel regions of the P-type cells (302). Then, PEPIs (410) are formed within the opening (1406P). Exemplary PEPIs (410) may comprise silicon, phosphorus-doped silicon, arsenic-doped silicon, antimony-doped silicon, or other suitable materials, and may be doped in situ during an epitaxial process by introducing an n-type dopant such as phosphorus, arsenic, or antimony, or may be doped ex situ using a bonding injection process. The patterned second mask layer (1408) may be optionally removed after the formation of the PEPIs (410). Referring to FIG. 13 and FIG. 20a through 20c, the method (1300) includes block 1314 in which additional processes are performed. These additional processes may include forming a dielectric structure (412), optionally removing gate stacks (1402) and sacrificial layers (406b) in channel regions, and forming gate structures (404). As shown by FIG. 20c, since the source / drain regions of the blank cells (306) are not reset to form openings for forming NEPIs or PEPIs, the source / drain regions of the blank cells (306) comprise a vertical stack of alternating channel layers (406a) (e.g., silicon) and sacrificial layers (406b) (e.g., silicon germanium), and the source / drain regions of the blank cells (306) (including the sacrificial layers (406b)) are in direct contact with the gate structure (404). These additional processes may also include forming gate vias, source / drain contacts, and metal lines on the transistors of the functional N-type cells (304) and functional P-type cells (302) to enable proper operation of the functional transistors. The transistors of the dummy N-type cells (304) and dummy P-type cells (302) and the features of the blank cells (306) are not electrically connected. FIG. 21 is a block diagram of a hardware system (2100) for implementing the methods and layout embodiments described with reference to FIG. 1 through 20c according to some embodiments. The system (2100) includes at least one processor (2102), a network interface (2104), an input and output (I / O) device (2106), storage (2108), memory (2112), and a bus (2110). The bus (2110) couples the network interface (2104), the I / O device (2106), the storage (2108), and the memory (2112) to the processor (2102). In some embodiments, memory (2112) includes random-access memory (RAM) and / or other volatile storage devices and / or read-only memory (ROM) and / or other non-volatile storage devices. Memory (2112) includes a kernel and user space configured to store program instructions to be executed by the processor (2102) and data accessed by the program instructions. In some embodiments, the network interface (2104) is configured to access program instructions stored remotely via the network and data accessed by the program instructions. The I / O device (2106) includes an input device and an output device configured to enable user interaction with the system (2100). The input device includes, for example, a keyboard, a mouse, etc. The output device includes, for example, a display, a printer, etc. The storage device (2108) is configured to store program instructions and data accessed by the program instructions. The storage device (2108) includes, for example, a magnetic disk and an optical disk. In some embodiments, when executing program instructions, the processor (2102) is configured to perform the method (100) and / or provide the layouts described above. In some embodiments, the program instructions are stored on one or more non-transient computer-readable recording media, such as optical disks, hard disks, and non-volatile memory devices. In some embodiments, a file containing the layouts described above is stored on a non-transient computer-readable storage medium. Based on the above description, it can be seen that the present disclosure provides advantages. However, other embodiments may provide additional advantages, and it is understood that not all advantages are necessarily disclosed herein, and that specific advantages are not required for all embodiments. For example, the present disclosure provides a system, structure, layout, and method that enables a chip to have an improved NPEI threshold dimension in terms of CD value and / or uniformity (CDU). n-type dummy cells and blank cells within a dummy region of a semiconductor structure may be selected and arranged (e.g., tuned) based on the design of the functional device region to provide improved CD and CDU. The present disclosure provides a number of different embodiments. A semiconductor structure and a method for manufacturing the same are disclosed herein. In one exemplary aspect, the present disclosure relates to a semiconductor structure. The semiconductor structure comprises a device region, and the device region comprises N1 first type device cells—each first type device cell comprises a plurality of operating N type devices—and P1 second type device cells—each second type device cell comprises a plurality of operating P type devices. The semiconductor structure also comprises a dummy region adjacent to the device region, and the dummy region comprises N2 first type dummy cells—each first type dummy cell comprises a plurality of non-operating N type devices—and P2 second type dummy cells—each second type dummy cell comprises a plurality of non-operating P type devices, and N1, P1, N2, and P2 are integers greater than or equal to 0, and the sum of N1 and N2 is substantially the same as the sum of P1 and P2. In some embodiments, the dummy region may also include a plurality of third-type dummy cells, each third-type dummy cell may include a non-operating gate structure over a fin-shaped active region, the fin-shaped active region extends longitudinally along a first direction and has a uniform composition along the first direction. In some embodiments, a plurality of operating N-type devices may include operating N-type transistors, and each of the operating N-type transistors may include a channel region on a substrate, n-type source / drain features coupled to the channel region, and an operating gate structure over the channel region. In some embodiments, the channel region may include a plurality of nanostructures, and an operating gate structure surrounds and lies over each of the plurality of nanostructures. In some embodiments, a plurality of non-operating N-type devices may include non-operating N-type transistors, and each of the non-operating N-type transistors may include a channel region on a substrate, n-type source / drain features coupled to the channel region, and an operating gate structure over the channel region. In some embodiments, the channel region may include a plurality of nanostructures, and a non-operating gate structure surrounds and lies over each of the plurality of nanostructures. In some embodiments, the number of N1 is greater than the number of P1, and the number of N2 is less than the number of P2. In some embodiments, when viewed from above, the first type dummy cells are spaced apart from the device region by the second type dummy cells. In some embodiments, the dummy region may also include M number of third type dummy cells, each third type dummy cell comprising a non-operating gate structure over a pin-shaped active region, the pin-shaped active region extends longitudinally along a first direction and has a uniform composition along the first direction, M is a positive integer, and the ratio of the number of M to the number of N1, the number of P1, the number of N2, and the number of P2 is less than 45%.In some embodiments, when viewed from above, third type dummy cells are placed between the second type dummy cells and the device area. In another exemplary embodiment, the present disclosure relates to a semiconductor structure. The semiconductor structure comprises a first channel region on a substrate, a first doped epitaxial feature coupled to the first channel region, a first gate structure on the first channel region, a second channel region on a substrate, a second epitaxial feature coupled to the second channel region, and a second gate structure on the second channel region, wherein the second epitaxial feature comprises a vertical stack of alternating first semiconductor layers and second semiconductor layers. In some embodiments, the semiconductor structure may also include a third channel region on a substrate, a doped third epitaxial feature coupled to the third channel region, and a third gate structure on the third channel region. In some embodiments, the doped first epitaxial feature and the doped third epitaxial feature have the same dopant polarity. In some embodiments, the doped first epitaxial feature and the doped third epitaxial feature have different dopant polarities. In some embodiments, the first channel region, the second channel region, and the third channel region may each include a plurality of first semiconductor layers. In some embodiments, the second gate structure is in direct contact with the second epitaxial feature. In another exemplary embodiment, the present disclosure relates to a method. The method comprises: providing a substrate having a first device region, a second device region, a first dummy region adjacent to the first device region and the second device region, and a second dummy region; forming a first active region, a second active region, a third active region, and a fourth active region, respectively, within the first dummy region, the second dummy region, the first device region, and the second device region; forming gate structures extending over the first active region, the second active region, the third active region, and the fourth active region; providing a first masking element having a first set of openings over the first dummy region and the first device region—the first masking element covers the second dummy region and the second device region—; and growing first epitaxial features having a first dopant type within the first dummy region and the first device region while providing the first masking element. The method comprises the steps of providing a second masking element having a second set of openings over a second dummy region and a second device region, wherein the second masking element covers a first dummy region and a first device region; and growing second epitaxial features having a second dopant type within the second dummy region and the second device region while providing the second masking element. In some embodiments, the first device region may include a plurality of functional N-type devices, the second device region may include a plurality of functional P-type devices, the first dummy region may include a plurality of non-functional N-type devices, the second dummy region may include a plurality of non-functional P-type devices, and the total number of functional P-type devices and non-functional P-type devices is equal to the total number of functional N-type devices and non-functional N-type devices. In some embodiments, the first active region, the second active region, the third active region, and the fourth active region may each include a stack of alternating channel layers and sacrificial layers on a substrate, and the method may also include, after growing the first epitaxial feature and the second epitaxial feature, selectively removing gate structures to form gate trenches, selectively removing portions of sacrificial layers disposed immediately below the gate structures to form gate openings, and forming gate stacks within the gate trenches and gate openings. In some embodiments, the gate stacks of the gate stacks within the second dummy region are in direct contact with the sacrifice layers. The foregoing provides an overview of the features of several embodiments. A person skilled in the art should be aware that they can readily use the disclosure of the present invention as a basis for devising or modifying other processes and structures to perform the same purposes and / or achieve the same advantages as the embodiments introduced herein. A person skilled in the art should also be aware that such equivalent configurations do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alternatives can be made without departing from the spirit and scope of the present disclosure. [Example 1] As a semiconductor structure, Device area; and Dummy area adjacent to the above device area Includes, The above device area is, N1 number of first-type device cells - each first-type device cell includes a plurality of operational N-type devices - and P1 number of second-type device cells - each second-type device cell includes a plurality of operational P-type devices. Includes, The above dummy area is, N2 first-type dummy cells - each first-type dummy cell includes a plurality of non-operational N-type devices - and P2 number of Type 2 dummy cells - each Type 2 dummy cell includes multiple non-operational P-type devices - Includes, A semiconductor structure in which N1, P1, N2, and P2 are integers greater than or equal to 0, and the sum of the number of N1 and the number of N2 is substantially the same as the sum of the number of P1 and the number of P2. [Example 2] In Example 1, A semiconductor structure wherein the above dummy region further comprises a plurality of third-type dummy cells, each third-type dummy cell comprises a non-operating gate structure on a fin-shaped active region, and the fin-shaped active region extends longitudinally along a first direction and has a uniform composition along the first direction. [Example 3] In Example 1, The above plurality of operating N-type devices include operating N-type transistors, and Each of the above-mentioned N-type transistors is, Channel region above the fin; n-type source / drain features coupled to the above channel region; and Operation gate structure above the channel area A semiconductor structure comprising [Example 4] In Example 3, A semiconductor structure in which the channel region comprises a plurality of nanostructures, and the operating gate structure wraps around and over each of the plurality of nanostructures. [Example 5] In Example 1, The above plurality of non-operating N-type devices include non-operating N-type transistors, and Each of the above non-operating N-type transistors is, Channel region on the substrate; n-type source / drain features coupled to the above channel region; and Non-operational gate structure above the channel region A semiconductor structure comprising [Example 6] In Example 5, A semiconductor structure wherein the channel region comprises a plurality of nanostructures, and the non-operating gate structure wraps around and over each of the plurality of nanostructures. [Example 7] In Example 1, A semiconductor structure in which the number of N1 is greater than the number of P1, and the number of N2 is smaller than the number of P2. [Example 8] In Example 7, A semiconductor structure in which, when viewed from above, the first type dummy cells are spaced apart from the device region by the second type dummy cells. [Example 9] In Example 7, The above dummy region further includes M number of third-type dummy cells, and Each third type dummy cell includes a non-operating gate structure on a pin-shaped active region, said pin-shaped active region extends longitudinally along a first direction and has a uniform composition along said first direction, A semiconductor structure in which M is a positive integer, and the ratio of the number of M to the total number of N1, P1, N2, and P2 is less than 45%. [Example 10] In Example 9, A semiconductor structure in which, when viewed from above, the third type dummy cells are disposed between the device region and the second type dummy cells. [Example 11] As a semiconductor structure, A first channel region on the substrate; A doped first epitaxial feature coupled to the first channel region; A first gate structure above the first channel region; A second channel region on the substrate above; A second epitaxial feature coupled to the second channel region; and The second gate structure above the second channel region Includes, A semiconductor structure wherein the second epitaxial feature comprises a vertical stack of alternating first semiconductor layers and second semiconductor layers. [Example 12] In Example 11, A third channel region on the substrate above; A doped third epitaxial feature coupled to the third channel region; and The third gate structure above the third channel area A semiconductor structure including more. [Example 13] In Example 12, A semiconductor structure in which the doped first epitaxial feature and the doped third epitaxial feature have the same dopant polarity. [Example 14] In Example 12, A semiconductor structure in which the doped first epitaxial feature and the doped third epitaxial feature have different dopant polarities. [Example 15] In Example 12, A semiconductor structure wherein the first channel region, the second channel region, and the third channel region each comprise a plurality of the first semiconductor layers. [Example 16] In Example 11, A semiconductor structure in which the second gate structure is in direct contact with the second epitaxial feature. [Example 17] As a method, A step of providing a substrate having a first device region, a second device region, a first dummy region and a second dummy region adjacent to the first device region and the second device region; A step of forming a first active region, a second active region, a third active region, and a fourth active region, respectively, within the first dummy region, the second dummy region, the first device region, and the second device region; A step of forming gate structures extending over the first active region, second active region, third active region, and fourth active region; Step of providing a first masking element having a first set of openings on the first dummy region and the first device region - the first masking element covers the second dummy region and the second device region - ; A step of growing first epitaxial features having a first dopant type within the first dummy region and the first device region while providing the first masking element; Step of providing a second masking element having a second set of openings on the second dummy region and the second device region - the second masking element covers the first dummy region and the first device region - ; and A step of growing second epitaxial features having a second dopant type within the second dummy region and the second device region while providing the second masking element. A method including [Example 18] In Example 17, A method wherein the first device region comprises a plurality of functional N-type devices, the second device region comprises a plurality of functional P-type devices, the first dummy region comprises a plurality of non-functional N-type devices, the second dummy region comprises a plurality of non-functional P-type devices, and the total number of the functional P-type devices and the non-functional P-type devices is equal to the total number of the functional N-type devices and the non-functional N-type devices. [Example 19] In Example 17, Each of the first active region, the second active region, the third active region, and the fourth active region comprises a stack of alternating channel layers and sacrificial layers on the substrate, and The above method is, After growing the first epitaxial feature and the second epitaxial feature, a step of selectively removing the gate structures to form gate trenches; A step of selectively removing portions of the sacrificial layers positioned immediately below the gate structures to form a gate opening; and Step of forming gate stacks within the gate trenches and gate openings A method that further includes. [Example 20] In Example 19, A method in which a gate stack among the gate stacks within the second dummy region is in direct contact with the sacrifice layers.

Claims

Claim 1 A semiconductor structure comprising: a device region; and a dummy region adjacent to the device region, wherein the device region comprises N1 first-type device cells - each first-type device cell comprises a plurality of operational N-type devices - and P1 second-type device cells - each second-type device cell comprises a plurality of operational P-type devices - and the dummy region comprises N2 first-type dummy cells - each first-type dummy cell comprises a plurality of non-operational N-type devices - and P2 second-type dummy cells - each second-type dummy cell comprises a plurality of non-operational P-type devices - and N1, P1, N2, and P2 are integers greater than or equal to 0, and the sum of the N1 number and the N2 number is equal to the sum of the P1 number and the P2 number. Claim 2 A semiconductor structure according to claim 1, wherein the dummy region further comprises a plurality of third-type dummy cells, each third-type dummy cell comprises a non-operating gate structure on a fin-shaped active region, and the fin-shaped active region extends longitudinally along a first direction and has a uniform composition along the first direction. Claim 3 A semiconductor structure according to claim 1, wherein the plurality of operating N-type devices include operating N-type transistors, and each of the operating N-type transistors includes a channel region on a fin; n-type source / drain features coupled to the channel region; and an operating gate structure on the channel region. Claim 4 A semiconductor structure according to paragraph 3, wherein the channel region comprises a plurality of nanostructures, and the operating gate structure wraps around and over each of the plurality of nanostructures. Claim 5 A semiconductor structure according to claim 1, wherein the plurality of non-operating N-type devices include non-operating N-type transistors, and each of the non-operating N-type transistors includes: a channel region on a substrate; n-type source / drain features coupled to the channel region; and a non-operating gate structure on the channel region. Claim 6 A semiconductor structure according to claim 5, wherein the channel region comprises a plurality of nanostructures, and the non-operating gate structure wraps around and over each of the plurality of nanostructures. Claim 7 A semiconductor structure according to claim 1, wherein the number of N1 is greater than the number of P1 and the number of N2 is smaller than the number of P2. Claim 8 A semiconductor structure according to claim 7, wherein, when viewed from above, the first type dummy cells are spaced apart from the device region by the second type dummy cells. Claim 9 A semiconductor structure according to claim 7, wherein the dummy region further comprises M third-type dummy cells, each third-type dummy cell comprises a non-operating gate structure on a fin-shaped active region, the fin-shaped active region extends longitudinally along a first direction and has a uniform composition along the first direction, M is a positive integer, and the ratio of the number of M to the total number of N1, P1, N2, and P2 is less than 45%. Claim 10 A method comprising: providing a substrate having a first device region, a second device region, a first dummy region and a second dummy region adjacent to the first device region and the second device region; forming a first active region, a second active region, a third active region, and a fourth active region, respectively, within the first dummy region, the second dummy region, the first device region, and the second device region; forming gate structures extending over the first active region, the second active region, the third active region, and the fourth active region; providing a first masking element having a first set of openings above the first dummy region and the first device region, wherein the first masking element covers the second dummy region and the second device region; growing first epitaxial features having a first dopant type within the first dummy region and the first device region while providing the first masking element; and a second masking having a second set of openings above the second dummy region and the second device region. A method comprising the step of providing an element - wherein the second masking element covers the first dummy region and the first device region -; and the step of growing second epitaxial features having a second dopant type within the second dummy region and the second device region while providing the second masking element.

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