Semiconductor circuit with metal structure having different pitches

#In semiconductor process development, it is usually required wafer acceptance test (WAT) at a lower level metal layer (such as the 1st or 2nd level metal layer) to have quick feedback on both device performance and process margin. However, this will face a test robustness problem when the technology and metal pitcher continuously scale down to smaller feature sizes in advanced technology nodes. Therefore it requires the metal thickness (depth) thinner to maintain metal trench aspect ratio (depth/width) to have enough process margins for various fabrication processes (such as etching and metal deposition) during the formation of the corresponding metal layer. For example, during the formation of metal lines in this metal layer by a damascene process, it is challenge to etch an interlayer dielectric material to form trenches and vias with high aspect ratios when the metal layer is thick. Furthermore, it is challenge to deposit a metal in the trenches and/vias with high aspect ratio. On other side, a thinner metal layer easily causes WAT test failure due to various factors, such as high contact resistance or open, or probe punching through the test pads. Thinner metal layer is also conflicted with lower level metal test requirement.

#Packing density is also a challenge when the semiconductor is scaled down to small feature sizes. For example, a logic circuit includes various logic gates, such as inverters, NAND gates, AND gates, NOR gates and flip-flop. In deep sub-micron integrated circuit technology, the logic circuit progressed to smaller feature sizes for higher packing density. However, the existing structure of a logic circuit still has various aspects to be improved for its performance and further enhanced packing density.

#It is therefore desired to have an integrated circuit design and structure, and the method making the same to address the above issues with increased packing density.

#Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

#FIG. 1 is a sectional view of a semiconductor structure constructed according to various aspects of the present disclosure in one embodiment.

#FIG. 2 is a top view of an interconnection gate and the metal lines in the semiconductor structure of FIG. 1, in accordance with some embodiments.

#It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

#FIG. 1 is a sectional view of a semiconductor structure 100 constructed according to various aspects of the present disclosure in one embodiment. In some embodiments, the semiconductor structure 100 is formed on fin active regions and includes fin field-effect transistors (FinFETs). In some embodiments, the semiconductor structure 100 is formed on flat fin active regions and includes effect transistors (FETs). In various embodiments, the semiconductor structure 100 includes one or more standard cell to be incorporated and repeatedly used to integrated circuit designs. Those standard cells may include various basic circuit devices, such as inverter, NAND, NOR, AND, OR, and flip-flop, which are popular in digital circuit design for applications, such as central processing unit (CPU), graphic processing unit (GPU), and system on chip (SOC) chip designs. In the present embodiment, the semiconductor structure 100 includes a standard cell defined in the dashed lines 101.

#The semiconductor structure 100 includes a semiconductor substrate 102. The semiconductor substrate 102 includes silicon. Alternatively, the substrate 102 may include an elementary semiconductor, such as silicon or germanium in a crystalline structure; a compound semiconductor, such as silicon germanium, silicon carbide, gallium arsenic, gallium phosphide, indium phosphide, indium arsenide, and/or indium antimonide; or combinations thereof. Possible substrates 102 also include a silicon-on-insulator (SOI) substrate. SOI substrates are fabricated using separation by implantation of oxygen (SIMOX), wafer bonding, and/or other suitable methods.