Method for auto enlarging bend portion width and computer readable recording medium for storing program thereof

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.

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. 1is a top view, schematically illustrating a conventional transistor which has a gate electrode with bend portion by 45 degrees. Referring toFIG. 1, the gate line120of the transistor100is designed to have 45-degree bend portion121, then the source contact window110and the drain contact window130are respectively implemented at two sides of the bend portion121. Therefore, the area of the transistor120can be significantly reduced.

However, during forming the gate line120with a line width W0, it is often that the edge of the bend portion121is over etched due to processing effect. As a result, the line width of the bend portion121is reduced to W1. If the line width W0is large enough, the influence of over etching is limited (W1is approximate to W0), thus, characteristic of the transistor100(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 transistor100, because the line width W0is thinner, the difference between W0and W1cannot be ignored. In order to ensure the ratio of length to width for the channel of the designed transistor100, a conventional method is to pre-enlarge the line width of the bend portion121to W2.

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=[(0.707Wbend−0.499Wnormal)/RES+1]*RES.
Wbendmeans the intended width, Wnormalmeans 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.

DESCRIPTION OF EMBODIMENTS

FIG. 2is 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 toFIG. 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. 3shows the condition that 45 degree bend of circuit line overlaps the polygon in the embodiment of this invention. Referring toFIG. 2andFIG. 3, the terminals of the center line of the 45 degree bend portion is a first turn point with coordinate (x2,y2) and a second turn point with coordinate (x3,y3), respectively. First, the step S210to S250is 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 P1to P6inFIG. 3), and the polygon width is the intended width. Then, the step S260is performed by adding the polygon to the original layout, and overlapping with the 45 degree bend portion.

In step S210, coordinates difference delta is calculated by:
Delta=[(0.707Wbend−0.499Wnormal)/RES+1]*RES.
Wbendmeans the intended width of the bend portion to be enlarged (usually, the intended width is determined according to design rule taken by the manufacturer), Wnormalmeans the original width, RES means the resolution of circuit layout. In aforesaid step S220, 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 (x1,y1) is selected as the first determination point inFIG. 3, and coordinate (x4,y4) is selected as the second determination point.

Considering that there are sixteen conditions for producing polygon with 45 degree bend portion, in step S230, 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 S230, a calculation formula is selected (S240-1to S240-16). Then, according to the selected calculation formula, each of the coordinates of the corner points of the polygon is obtained (step S250).

The foregoing 16 kinds of conditions for producing polygons with 45 degree bend are described below by referencing withFIG. 3toFIG. 16. The coordinates of the first determination point, the first turn point, the second turn point and the second determination point are (x1,y1), (x2,y2),(x3,y3) and (x4,y4) respectively, and w means Wnormal/2.

First Condition:

Fourteenth Condition

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.