Dung dịch hiện Developer cho phép hiện hình những chi tiết tạo ra trên lớp cảm quang do tác dụng của nguồn UV. Quá trình này giống như quá trình rửa ảnh trong kỹ thuật nhiếp ảnh. | placement of other cells. At some point in the design process the SLL must be converted to a geometrical specification language for use by other CAD tools and for transmittal to the mask shop. XPOINT and YPOINT must be assigned numerical values to specify the location of the geometry before this conversion takes place. In addition to the use of symbolic parameters in an SLL programming constructs such as loops and conditionals can provide additional capability in the specification of a cell s layout. The use of an SLL to describe layout is much like the use of assembly language to describe the machine language binary program for a computer. An assembly language program uses mnemonics for the instructions and symbols for variables to simplify and expedite the process of programming a digital computer. Both forms describe the same end object the binary representation provides the most concise description while the assembly language is a preferable working medium for programmers An SLL description for the layout of the CMOS inverter of Fig. is given in Fig. . Note the verbose nature of this description compared to the geometrical specification file of Fig. . The description of Fig. demonstrates the use of variables to allow the inverter cell of Fig. to be stretched in either the VERT vertical or HORZ horizontal directions. Also a REPEAT statement is included to allow the cell to be repeated NR limes. RX and RY are the repeat distances along the A and y axes respectively. If the variables VERT and HORZ are each set to a value of 0 and NR is set to 4 the inverter cascade of Fig. is produced. The two variables VERT and HORZ can be used to stretch the inverter cell to match the pitch of adjacent cells by CELLNAME CMOS I NV BOX ND 1 F X-3 Y-0 DX 4 DY-4 BOX ND 1 F X-3 Y 4 DX-2 DY-4 BOX ND f F X-3 Y -8 DX 4 DY 4 BOX PD 1 F x 3 Y 20 DX-4 DY 4 BOX PD 1 F x 3 Y-24 DX-5 DY 4 BOX PD 1 F x 3 Y-28 DX 4 DY-4 BOX POLY X-0 Y-5 DX 7 DY-2 BOX POLY x
