1. Preparation of IC layout design
Complete the circuit principle diagram design, into the integrated circuit layout design, IC layout design of EDA tool system based on the platform, must rely on technology, which reflects the layout design rules set in the manufacturer, so in the layout design before the need to do the following work:
①Mastering the use of the layout editing module and the layout verification module tool in the nine day EDA system. Figure 1 shows the basic process of layout design under the ZeniLE environment. The layout validation process for ZeniVERI is shown in Figure 2.
②Read and understand the layout design rules. Design rules for electrical properties of geometry in the production of acceptable requirements and can be reached, these rules are a circuit between designers and process engineers to restrict each other contact means, layout design rules to make design standardization, and use these rules in the best yield and ensure the reliability of the circuit under the premise the minimum layout area as much as possible.
③The layout verification command file (command file) is designed. The layout validation requires four files (DRC, ERC, NE, and LVS) to support, and the nine day EDA system supports the Dracula form of the command file.
④If a semi custom standard unit is used to design the layout, a layout library with a uniform height of the basic circuit unit layout is needed to support it. These units can be different types of gate circuits, or flip flops, full adder, registers and other functional circuits. We can set up the library of graphics on the basis of the first three preparations. The semi customizing method can simplify the design and reduce the design cycle.
2. Layout design of IC layout
At present, nine days, EDA system can't automatically generate layout automatically, and manual layout design is needed in the layout edit module of ZeniLE. The layout of the integrated circuit layout includes layout, unit configuration and wiring. Generally, the layout should be reasonable, the unit is properly configured and the wiring is appropriate.
2.1 the layout should be reasonable
The rationality of integrated circuit layout design refers to the rationality of the chip function requirements and pinout layout logic IC is composed by different network register, adder and control logic circuit, the chip can be divided into many small regions, the logical arrangement of components in each area. Several criteria for examining the rationality of the layout are:
①Whether the distribution of the elicited end is used or compatible with the related circuit; whether it is in line with the arrangement requirements of the elicited line of the shell and shell.
②The unit with special requirements (for example, symmetry, proximity or far away) is properly arranged. For example, in the layout of CMOS circuit, we should try to keep the N area of N well and N tube far away from each other so as to reduce the value of beta NPN, which is especially important for output stage.
③If the layout is compact, in order to maximize the density of the package, we want the whole chip to be square as much as possible.
④The temperature distribution should be reasonable. The heating element is generally required to be placed in the center of the chip.