Abstract:
A method for auto enlarging bend portion width and a computer readable recording medium for storing program thereof are provided. The method can enlarge the bend portion width from an original width to an intended width in layout. Wherein, the terminals of the center line of the bend is a first turn point and a second turn point, respectively. The method includes following steps. First calculating the original width, the intended width, the coordinates of the first turn point and the second turn point to obtain a plurality coordinates of the corner-points of the polygon. Wherein, the width of the polygon is the intended width. Then add the polygon into the original layout.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a method of electric circuit layout, and particularly to automatic enlarging width of bend portion, and computer readable recording medium for storing program with aforesaid method. 
     2. Prior Art 
     In electric circuit layout, it is needed to implement a plurality of longitudinal and latitudinal circuit lines (leads) to obtain electric connection between the devices. Generally, aforesaid longitudinal and latitudinal electric lines interconnect by 90 degree angle. In considering on some electric characteristics or electric circuit area, a bend portion is usually needed to be implemented in the electric circuit sometimes. For example, in an integrated circuit, a gate electrode of transistor is designed to be a circuit line with 45 degree bending for saving electric circuit area. 
       FIG. 1  is a top view, schematically illustrating a conventional transistor which has a gate electrode with bend portion by 45 degrees. Referring to  FIG. 1 , the gate line  120  of the transistor  100  is designed to have 45-degree bend portion  121 , then the source contact window  110  and the drain contact window  130  are respectively implemented at two sides of the bend portion  121 . Therefore, the area of the transistor  120  can be significantly reduced. 
     However, during forming the gate line  120  with a line width W 0 , it is often that the edge of the bend portion  121  is over etched due to processing effect. As a result, the line width of the bend portion  121  is reduced to W 1 . If the line width W 0  is large enough, the influence of over etching is limited (W 1  is approximate to W 0 ), thus, characteristic of the transistor  100  (ratio of length to width of the channel) has no change almost. But, when more an advanced process (for example, process with line width smaller than 0.25 microns) is used to fabricate the transistor  100 , because the line width W 0  is thinner, the difference between W 0  and W 1  cannot be ignored. In order to ensure the ratio of length to width for the channel of the designed transistor  100 , a conventional method is to pre-enlarge the line width of the bend portion  121  to W 2 . 
     In the present practice, after circuit layout is finished by using the tool of electronic design automation, the 45 degree bend portion is manually searched one by one, and then the electronic design automation tools are manually manipulated to pull each edge of the 45 degree bend portion outward to be wider. Hence, in order to enlarge the line width of the 45 degree bend portion, often, much time is spent on circuit layout modification in layout engineering. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a method for automatically enlarging the width of the bend portion, the method can enlarge the width of the bend portion automatically without manual operation. The efficiency of layout can be improved. 
     Another objective of the present invention is to provide a computer readable recording medium for storing a program for the foregoing intended. 
     The present invention provides a method for automatically enlarging a width of a bend portion. The method can enlarge the width of the bend portion from an original width to an intended width in layout. The terminals of the center line of the bend portion are a first turn point and a second turn point, respectively. The method includes following steps. First, the original width, the intended width, the coordinates of the first turn point and the second turn point are used in calculation to obtain a plurality coordinates of the corner-points of the polygon. The width of the polygon is the desired intended width. Then, the polygon is added into the original layout, overlapping with the bend portion. 
     According to the method for automatically enlarging a width of a bend portion in a preferred embodiment of the invention, the calculation to obtain a plurality of coordinates of the corner-points of the polygon includes following steps. First, one point at each of the circuits coupled to the two terminals of the bend portion is selected as a first determination point and a second determination point, respectively. According to the first determination point, the second determination point, the first turn point and the second turn point, a corresponding calculation formula is determined, to obtain each coordinate of the corner-points of the polygon. 
     According to the method for automatically enlarging a width of the bend portion in a preferred embodiment of the invention, wherein the bend portion of the electric circuit bend portion is a 45 degree bend portion. Therefore, the step of calculation and obtaining the coordinates of the corner-points of the polygon includes following equation to get a coordinate difference of delta:
 
Delta=[(0.707 W   bend −0.499 W   normal )/RES+1]*RES.
 
W bend  means the intended width, W normal  means an original width, and the RES means a resolution of circuit layout.
 
     In addition, the present invention provides a computer readable recording medium for storing program which is executable in computer system. The program can be used to enlarge the line width of the bend portion circuit line on the circuit layout from original width to intended width. The two terminals of the center line of the bend portion are a first turn point and a second turn point, respectively. The program includes following sets of instructions for reading out the layout, calculating the original width, the intended width, the coordinates of the first turn point and the second turn point, and obtaining a plurality coordinates of the corner-points of the polygon. The width of the bend portion is the intended width. And, the polygon is added into the original layout, and overlapping with the bend portion. 
     This invention can be used to calculate the original width, the intended width, the coordinates of the first turn point and the second turn point, and to obtain a plurality coordinates of the corner-points of the polygon. The width of the polygon is the intended width, the polygon is added into the original layout, overlapping with the bend portion. Therefore, this invention can enlarge the width of the bend portion automatically without manual operation, and improve efficiency of layout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.  FIG. 1  is a top view, schematically illustrating the bend gate electrode of a conventional transistor. 
         FIG. 2  is a process diagram, schematically illustrating the process of automatically enlarging a line width of the bend portion, according to a preferred embodiment of the invention. 
         FIGS. 3-18  are drawings, schematically illustrating the overlapping between the bend portion of electric circuit and the polygon. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 2  is a process diagram, schematically illustrating the process of automatically enlarging a line width of the bend portion, according to a preferred embodiment of the invention. Referring to  FIG. 2 , the method is used to enlarge circuit line bend portion width from original width to the intended width. In the embodiment, the circuit line can be the gate of transistor or the metal interconnection wire. 
     In order to easily describe the invention, an embodiment is taken to describe the method for auto-enlarging bend portion width in 45 degree bend. To those skilled in the ordinary art, the bend with any angle and the geometry shape can be extended according to the invention and the embodiment described below. In other words, the scope of this invention shall not be limited by following embodiments. 
       FIG. 3  shows the condition that 45 degree bend of circuit line overlaps the polygon in the embodiment of this invention. Referring to  FIG. 2  and  FIG. 3 , the terminals of the center line of the 45 degree bend portion is a first turn point with coordinate (x 2 ,y 2 ) and a second turn point with coordinate (x 3 ,y 3 ), respectively. First, the step S 210  to S 250  is performed. a calculation is performed, according to the original width, the intended width, the coordinates of the first turn point and the second turn point to obtain a plurality coordinates of the corner-points of the polygon (for example, corner points P 1  to P 6  in  FIG. 3 ), and the polygon width is the intended width. Then, the step S 260  is performed by adding the polygon to the original layout, and overlapping with the 45 degree bend portion. 
     In step S 210 , coordinates difference delta is calculated by:
 
Delta=[(0.707 W   bend −0.499 W   normal )/RES+1]*RES.
 
W bend  means the intended width of the bend portion to be enlarged (usually, the intended width is determined according to design rule taken by the manufacturer), W normal  means the original width, RES means the resolution of circuit layout. In aforesaid step S 220 , a first determination point and a second determination point are respectively set from any point in each of the circuits coupled to the terminals of the 45 degree bend portion. For example, coordinate (x 1 ,y 1 ) is selected as the first determination point in  FIG. 3 , and coordinate (x 4 ,y 4 ) is selected as the second determination point.
 
     Considering that there are sixteen conditions for producing polygon with 45 degree bend portion, in step S 230 , a corresponding calculation formula is determined by the first determination point, the second determination point, the first turn point and the second turn point. Then, following the result of step S 230 , a calculation formula is selected (S 240 - 1  to S 240 - 16 ). Then, according to the selected calculation formula, each of the coordinates of the corner points of the polygon is obtained (step S 250 ). 
     The foregoing 16 kinds of conditions for producing polygons with 45 degree bend are described below by referencing with  FIG. 3  to  FIG. 16 . The coordinates of the first determination point, the first turn point, the second turn point and the second determination point are (x 1 ,y 1 ), (x 2 ,y 2 ),(x 3 ,y 3 ) and (x 4 ,y 4 ) respectively, and w means W normal /2. 
     First Condition: 
     Referring to  FIG. 2  and  FIG. 3  simultaneously, when the determined results of the step S 230  is x 1 =x 2 , y 1 &lt;y 2 , x 2 &lt;x 3 , y 2 &lt;y 3 , x 3 =x 4 , y 3 &lt;y 4 , step S 240 - 1  is selected. Then, according to following formulas (first sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 3 +w, y 3+delta);
 
 P 2=( x 3 +w, y 3−delta);
 
 P 3=( x 2 +w, y 2−delta);
 
 P 4=( x 2 −w, y 2−delta);
 
 P 5=( x 2 −w, y 2+delta);
 
 P 6=( x 3 −w, y 3+delta).
 
     Second Condition: 
     Referring to  FIG. 2  and  FIG. 4  simultaneously, when the determined result of step S 230  is x 1 =x 2 , y 1 &gt;y 2 , x 2 &gt;x 3 , y 2 &gt;y 3 , x 3 =x 4 , y 3 &gt;y 4 , step S 240 - 2  is selected. Then, according to following formulas (second sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 2 +w, y 2+delta);
 
 P 2=( x 2 +w, y 2−delta);
 
 P 3=( x 3 +w, y 3−delta);
 
 P 4=( x 3 −w, y 3−delta);
 
 P 5=( x 3 −w, y 3+delta);
 
 P 6=( x 2 −w, y 2+delta).
 
     Third Condition: 
     Referring to  FIG. 2  and  FIG. 5  simultaneously, when the determined result of step S 230  is x 1 =x 2 , y 1 &lt;y 2 , x 2 &gt;x 3 , y 2 &lt;y 3 , x 3 =x 4 , y 3 &lt;y 4 , the step S 240 - 3  is selected. Then, according to following formulas (third sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 p 1=( x 3 +w, y 3+delta);
 
 p 2=( x 2 +w, y 2+delta);
 
 p 3=( x 2 +w, y 2−delta);
 
 p 4=( x 2 −w, y 2−delta);
 
 p 5=( x 3 −w, y 3−delta);
 
 p 6=( x 3 −w, y 3+delta).
 
     Fourth Condition: 
     Referring to  FIG. 2  and  FIG. 6  simultaneously, when the determined result of step S 230  is x 1 =x 2 , y 1 &gt;y 2 , x 2 &lt;x 3 , y 2 &gt;y 3 , x 3 =x 4 , y 3 &gt;y 4 , the step S 240 - 4  is selected. Then, according to following formulas (fourth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 2 +w, y 2+delta);
 
 P 2=( x 3 +w, y 3+delta);
 
 P 3=( x 3 +w, y 3−delta);
 
 P 4=( x 3 −w, y 3−delta);
 
 P 5=( x 2 −w, y 2−delta);
 
 P 6=( x 2 −w, y 2+delta).
 
     Fifth Condition: 
     Referring to  FIG. 2  and  FIG. 7  simultaneously, when the determined result of step S 230  is x 1 &lt;x 2 , y 1 =y 2 , x 2 &lt;x 3 , y 2 &lt;y 3 , x 3 &lt;x 4 , y 3 =y 4 , the step S 240 - 5  is selected. Then, according to following formulas (fifth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 3+delta,  y 3 +w );
 
 P 2=( x 3+delta,  y 3 −w );
 
 P 3=( x 2+delta,  y 2 −w );
 
 P 4=( x 2−delta,  y 2 −w );
 
 P 5=( x 2−delta,  y 2 +w );
 
 P 6=( x 3−delta,  y 3 +w ).
 
     Sixth Condition: 
     Referring to  FIG. 2  and  FIG. 8  simultaneously, when the determined result of step S 230  is x 1 &gt;x 2 , y 1 =y 2 , x 2 &gt;x 3 , y 2 &gt;y 3 , x 3 &gt;x 4 , y 3 =y 4 , the step S 240 - 6  is selected. Then, according to following formulas (sixth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 2+delta,  y 2 +w );
 
 P 2=( x 2+delta,  y 2 −w );
 
 P 3=( x 3+delta,  y 3 −w );
 
 P 4=( x 3−delta,  y 3 −w );
 
 P 5=( x 3−delta,  y 3 +w );
 
 P 6=( x 2−delta,  y 2 +w ).
 
     Seventh Condition: 
     Referring to  FIG. 2  and  FIG. 9  simultaneously, when the determined result of step S 230  is x 1 &lt;x 2 , y 1 =y 2 , x 2 &lt;x 3 , y 2 &gt;y 3 , x 3 &lt;x 4 , y 3 =y 4 , the step S 240 - 7  is selected. Then, according to following formulas (seventh sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 3+delta,  y 3 +w );
 
 P 2=( x 3+delta,  y 3 −w );
 
 P 3=( x 3−delta,  y 3 −w );
 
 P 4=( x 2−delta,  y 2 −w );
 
 P 5=( x 2−delta,  y 2 +w );
 
 P 6=( x 2+delta,  y 2 +w ).
 
     Eighth Condition: 
     Referring to  FIG. 2  and  FIG. 10  simultaneously, when the determined result of step S 230  is x 1 &gt;x 2 , y 1 =y 2 , x 2 &gt;x 3 , y 2 &lt;y 3 , x 3 &gt;x 4 , y 3 =y 4 , the step S 240 - 8  is selected. Then, according to following formulas (eighth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 2+delta,  y 2 +w );
 
 P 2=( x 2+delta,  y 2 −w );
 
 P 3=( x 2−delta,  y 2 −w );
 
 P 4=( x 3−delta,  y 3 −w );
 
 P 5=( x 3−delta,  y 3 +w );
 
 P 6=( x 3+delta,  y 3 +w ).
 
     Ninth Condition: 
     Referring to  FIG. 2  and  FIG. 11  simultaneously, when the determined result of step S 230  is x 1 &gt;x 2 , y 1 =y 2 , x 2 &gt;x 3 , y 2 &lt;y 3 , x 3 =x 4 , y 3 &lt;y 4 , the step S 240 - 9  is selected. Then, according to following formulas (ninth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 2+delta,  y 2 +w );
 
 P 2=( x 2+delta,  y 2 −w );
 
 P 3=( x 2−delta,  y 2 −w );
 
 P 4=( x 3 −w, y 3−delta);
 
 P 5=( x 3 −w, y 3+delta);
 
 P 6=( x 3 +w, y 3+delta).
 
     Tenth Condition: 
     Referring to  FIG. 2  and  FIG. 12  simultaneously, when the determined result of step S 230  is x 1 =x 2 , y 1 &gt;y 2 , x 2 &lt;x 3 , y 2 &gt;y 3 , x 3 &lt;x 4 , y 3 =y 4 , the step S 240 - 10  is selected. Then, according to following formulas (tenth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 3+delta,  y 3 +w );
 
 P 2=( x 3+delta,  y 3 −w );
 
 P 3=( x 3−delta,  y 3 −w );
 
 P 4=( x 2 −w, y 2−delta);
 
 P 5=( x 2 −w, y 2+delta);
 
 P 6=( x 2 +w, y 2+delta).
 
     Eleventh Condition: 
     Referring to  FIG. 2  and  FIG. 13  simultaneously, while determination result of step S 230  is x 1 =x 2 , y 1 &gt;y 2 , x 2 &gt;x 3 , y 2 &gt;y 3 , x 3 &gt;x 4 , y 3 =y 4 , the step S 240 - 11  is selected. Then, according to following formulas (eleventh sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 2 +w, y 2+delta);
 
 P 2=( x 2 +w, y 2−delta);
 
 P 3=( x 3−delta,  y 3 −w );
 
 P 4=( x 3−delta,  y 3 −w );
 
 P 5=( x 3−delta,  y 3 +w );
 
 P 6=( x 2 −w, y 2+delta).
 
     Twelfth Condition: 
     Referring to  FIG. 2  and  FIG. 14  simultaneously, when the determined result of step S 230  is x 1 &lt;x 2 , y 1 =y 2 , x 2 &lt;x 3 , y 2 &lt;y 3 , x 3 =x 4 , y 3 &lt;y 4 , the step S 240 - 12  is selected. Then, according to following formulas (twelfth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 3 +w, y 3+delta);
 
 P 2=( x 3 +w, y 3−delta);
 
 P 3=( x 2+delta,  y 2 −w );
 
 P 4=( x 2−delta,  y 2 −w );
 
 P 5=( x 2−delta,  y 2 +w );
 
 P 6=( x 3 −w, y 3+delta).
 
     Thirteenth Condition: 
     Referring to  FIG. 2  and  FIG. 15  simultaneously, when the determined result of step S 230  is x 1 =x 2 , y 1 &lt;y 2 , x 2 &lt;x 3 , y 2 &lt;y 3 , x 3 &lt;x 4 , y 3 =y 4 , the step S 240 - 13  is selected. Then, according to following formulas (thirteenth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 3+delta,  y 3 +w );
 
 P 2=( x 3+delta,  y 3 −w );
 
 P 3=( x 2 +w, y 2−delta);
 
 P 4=( x 2 −w, y 2−delta);
 
 P 5=( x 2 −w, y 2+delta);
 
 P 6=( x 3−delta,  y 3 +w ).
 
     Fourteenth Condition 
     Referring to  FIG. 2  and  FIG. 16  simultaneously, when the determined result of step S 230  is x 1 &gt;x 2 , y 1 =y 2 , x 2 &gt;x 3 , y 2 &gt;y 3 , x 3 =x 4 , y 3 &gt;y 4 , the step S 240 - 14  is selected. Then, according to following formulas (fourteenth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 2delta,  y 2 +w );
 
 P 2=( x 2delta,  y 2 −w );
 
 P 3=( x 3 +w, y 3−delta);
 
 P 4=( x 3 −w, y 3−delta);
 
 P 5=( x 3 −w, y 3+delta);
 
 P 6=( x 2delta,  y 2 +w ).
 
     Fifteenth Condition: 
     Referring to  FIG. 2  and  FIG. 17  simultaneously, when the determined result of step S 230  is x 1 &lt;x 2 , y 1 =y 2 , x 2 &lt;x 3 , y 2 &gt;y 3 , x 3 =x 4 , y 3 &gt;y 4 , the step S 240 - 15  is selected. Then, according to following formulas (fifteenth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 3 +w, y 3+delta);
 
 P 2=( x 3 +w, y 3−delta);
 
 P 3=( x 3 −w, y 3−delta);
 
 P 4=( x 2delta,  y 2   2 −w );
 
 P 5=( x 2delta,  y 2   2 +w );
 
 P 6=( x 2delta,  y 2   2 +w ).
 
     Sixteenth Condition: 
     Referring to  FIG. 2  and  FIG. 18  simultaneously, when the determined result of step S 230  is x 1 =x 2 , y 1 &lt;y 2 , x 2 &gt;x 3 , y 2 &lt;y 3 , x 3 &gt;x 4 , y 3 =y 4 , the step S 240 - 16  is selected. Then, according to following formulas (sixteenth sets of formulas), the corner points P 1 -P 6  of the polygon are respectively obtained:
 
 P 1=( x 2 +w, y 2+delta);
 
 P 2=( x 2 +w, y 2−delta);
 
 P 3=( x 2 −w, y 2−delta);
 
 P 4=( x 3−delta,  y 3 −w );
 
 P 5=( x 3−delta,  y 3 +w );
 
 P 6=( x 3+delta,  y 3 +w ).
 
     In conclusion, this invention can be used to calculate the original width, the intended width, the coordinates of the first turn point and the second turn point to obtain a plurality coordinates of the corner-points of the polygon, then adding the polygon into the original layout, overlapping with bend. Therefore, this invention can enlarge the width of the 45 degree bend portion automatically without manual operation, and improve efficiency of layout. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.