The analysis of the local pattern density of chip and inspection method
Technical field
The present invention relates to semiconductor integrated circuit and make the field, particularly relate to a kind of analysis and inspection method of pattern density of chip.
Background technology
Along with the continuous progress of integrated circuit processing technique, especially after 0.13 micron technique, the live width of silicon technology is all less than the wavelength length of exposing, so that the stability of technique is more and more difficult.The spin-off effects that just begins to consider technique early stage in design has produced a lot of Design Rule Checking (DRC, Design Rule Check) thus.Design Rule Checking comprises a lot of aspects.Wherein, the pattern density of whole and part (Pattern Density) all has a significant impact for macroscopical load (Macro Loading) of cmp (CMP, ChemicalMechanical Polarization) and etching.Just exist owing to active area (AA, Active Area) pattern density is violated design rule in the prior art, but DRC does not have inspection out, directly causes the case of product failure.
The Design Rule Checking of present local pattern density, be mainly: chip (chip) is divided into a plurality of local chip pieces according to the specific portion area, carry out the calculating of the pattern density of each described local chip piece, judge whether the pattern density of the described local chip piece of each piece reaches targeted graphical density.Described targeted graphical density range is according to CMP and the grand load request of etching technics, and according to the process layer under the described figure by he design rules specify.As shown in Figure 2, schematic diagram for the local pattern density inspection method one of prior art chip, this moment, step-length equaled the length of side of local chip piece, wherein the large square of solid line is chip, the little square of solid line is the local chip piece of first measurement pattern density, and dotted line is the local chip piece through second the adjacent measurement pattern density after the step-length.As shown in Figure 3, schematic diagram for the local pattern density inspection method two of prior art chip, step-length is less than the length of side of local chip piece at this moment, wherein the large square of solid line is chip, the little square of solid line is the local chip piece of first measurement pattern density, dotted line is the local chip piece through second measurement pattern density after the step-length, and second local chip piece can be overlapping with previous local chip piece.
Above-mentioned inspection method one and two all can be omitted certain situation, causes to check unsuccessfully.As shown in Figure 4, the large square of solid line is chip, and the little square of solid line is the local chip piece of measurement pattern density, and the little square of dotted line is the local chip piece that does not satisfy design rule of pattern density; Because prior art can only be measured the local chip piece shown in the little square of solid line, and can not be by measuring for the pattern density of the local chip piece shown in the little square of dotted line, so even when the pattern density of the local chip piece shown in the little square of all solid lines all reached targeted graphical density, the pattern density that can not determine the local chip piece shown in the little square of dotted line was normal value; When the pattern density of the local chip piece shown in the little square of dotted line exceeds desired value, will make the product failure.So existing, the local pattern density inspection method of prior art chip checks the blind area, so that the local chip piece shown in the little square of Fig. 4 dotted line is missed.
But, if simply local area is dwindled, can cause a lot of false alarms, must artificial examination, can not reach so on the contrary the effect of inspection.
Summary of the invention
Technical problem to be solved by this invention provides a kind of analysis and inspection method of local pattern density of chip, can check that pattern density occurs in the false alarm situation not increasing, and increases the checking ability of pattern density.
For solving the problems of the technologies described above, the analysis of the local pattern density of chip provided by the invention and inspection method comprise the steps:
Step 1, according to the size of the grand load request definition of cmp and etching technics local area; Described chip is divided into the structure that the local chip piece by a plurality of homalographics forms, and the area of each described local chip piece equals described local area; The size range of described local area is 0.0025 micron
2~250000 microns
2The shape of described local chip piece can be any special pattern such as rectangle, circle or oval etc.
Step 2, be the structure that the local chip fritter by a plurality of homalographics forms with each described local chip piece cutting, the area of each described local chip fritter is the fritter area.Each described local chip piece cutting is that the umber of local chip fritter is: 2~10
10Described local chip fritter is a special pattern such as rectangle, triangle etc.
Step 3, measure the pattern density of each described local chip fritter.
Step 4, according to the pattern density value of each measured described local chip fritter and draw out the two-dimentional contour map of the pattern density of described chip according to the physical location of each described local chip fritter on described chip.
Step 5, according to described two-dimentional contour map, the area that whether exists that the method that adopts manual calculations or programming to calculate is calculated in described two-dimentional contour map exceeds the zone of targeted graphical density range greater than described local area and pattern density value; Described targeted graphical density range is according to CMP and the grand load request of etching technics, and according to the process layer under the described figure by he design rules specify.
If the exist area of step 6 in described two-dimentional contour map exceeds the zone of targeted graphical density range greater than described local area and pattern density value, then need to revise design configuration; If the area that do not exist in described two-dimentional contour map exceeds the zone of targeted graphical density range greater than described local area and pattern density value, then do not need to revise design configuration.
Beneficial effect of the present invention is:
1, the present invention can increase the checking ability of pattern density, and method directly, simply is not easy to omit the zone of not satisfying pattern density.
2, because the present invention need not dwindle local area, namely not the checking ability that improves pattern density by dwindling local area, so the present invention can avoid too much false alarm occurring owing to dwindling local area.
Description of drawings
The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments:
Fig. 1 is the flow chart of the inventive method;
Fig. 2 is the schematic diagram of the local pattern density inspection method one of prior art chip;
Fig. 3 is the schematic diagram of the local pattern density inspection method two of prior art chip;
Fig. 4 is the local pattern density inspection method of prior art chip schematic diagram when undetected;
Fig. 5 is the two-dimentional contour map that embodiment of the invention method is drawn.
Embodiment
The below enumerates an embodiment of the invention and in conjunction with prior art advantage of the present invention is described.Chip for a requirement is measured is divided into the local chip piece of a plurality of rectangles to described chip according to the size of a local area, and supposes that the targeted graphical density range of the described local chip piece with local area size of this kind chip is<=30%.In embodiments of the present invention, described chip is divided into directions X 3 equal portions according to the size of described local area, 12 identical described local chip pieces of Y-direction 4 equal portions.
One, adopt a pair of described chip of local pattern density inspection method of prior art chip to check, obtain data as described in Table 1, can find out the pattern density that has checked altogether 12 each described local chip piece, and the pattern density of all described local chip pieces is all less than 30%.The check result that is the local pattern density inspection method one of prior art chip is qualified.
Table 1
X/Y |
X1 |
X2 |
X3 |
Y1 |
0.24 |
0.24 |
0.19 |
Y2 |
0.19 |
0.28 |
0.27 |
Y3 |
0.28 |
0.25 |
0.19 |
Y4 |
0.21 |
0.24 |
0.25 |
Two, adopt two pairs of described chips of local pattern density inspection method of prior art chip to check, the step-length of supposing directions X and Y-direction all is kept to above-mentioned half, and obtaining area as described in Table 2 is the pattern density data of the local chip piece of local area size.Can find out that the pattern density of all described local chip pieces is all less than 30%.The check result that is the local pattern density inspection method two of prior art chip is qualified.
Table 2
X/Y |
X1 |
X2 |
X3 |
X4 |
X5 |
Y1 |
0.24 |
0.26 |
0.24 |
0.22 |
0.19 |
Y2 |
0.23 |
0.28 |
0.28 |
0.23 |
0.21 |
Y3 |
0.19 |
0.26 |
0.28 |
0.27 |
0.27 |
Y4 |
0.21 |
0.27 |
0.28 |
0.26 |
0.23 |
Y5 |
0.28 |
0.28 |
0.25 |
0.24 |
0.19 |
Y6 |
0.26 |
0.25 |
0.23 |
0.25 |
0.24 |
Y7 |
0.21 |
0.24 |
0.24 |
0.27 |
0.25 |
Three, adopt analysis and the inspection method of the local pattern density of the chip that the embodiment of the invention provides that described chip is checked, after according to above-mentioned described local area described chip being divided into the described local chip piece of 12 identical rectangular shapes, also comprise the steps:
Step 2, be the structure that the local chip fritter by a plurality of homalographics forms with each described local chip piece cutting, cutting method is: each described local chip carries out obtaining in the cutting of directions X 4 equal portions, Y-direction 4 equal portions the described local chip fritter of 16 identical rectangular shapes.
Step 3, measure the pattern density of each described local chip fritter; Obtain data as described in Table 3.Can find out that the pattern density of the described local chip fritter of part is greater than 30%.
Table 3
X/Y |
X1 |
X2 |
X3 |
X4 |
X5 |
X6 |
X7 |
X8 |
X9 |
X10 |
X11 |
X12 |
Y1 |
0.15 |
0.21 |
0.26 |
0.24 |
0.13 |
0.31 |
0.24 |
0.18 |
0.26 |
0.41 |
0.17 |
0.18 |
Y2 |
0.26 |
0.28 |
0.36 |
0.27 |
0.15 |
0.26 |
0.13 |
0.17 |
0.16 |
0.14 |
0.09 |
0.22 |
Y3 |
0.25 |
0.16 |
0.24 |
0.24 |
0.24 |
0.21 |
0.19 |
0.34 |
0.37 |
0.11 |
0.08 |
0.24 |
Y4 |
0.26 |
0.18 |
0.11 |
0.35 |
0.39 |
0.37 |
0.28 |
0.25 |
0.23 |
0.09 |
0.1 |
0.17 |
Y5 |
0.15 |
0.16 |
0.13 |
0.39 |
0.33 |
0.35 |
0.24 |
0.18 |
0.26 |
0.24 |
0.23 |
0.15 |
Y6 |
0.26 |
0.21 |
0.19 |
0.37 |
0.21 |
0.39 |
0.28 |
0.15 |
0.18 |
0.35 |
0.21 |
0.33 |
Y7 |
0.19 |
0.14 |
0.09 |
0.32 |
0.33 |
0.31 |
0.26 |
0.29 |
0.41 |
0.33 |
0.34 |
0.25 |
Y8 |
0.18 |
0.11 |
0.08 |
0.12 |
0.35 |
0.19 |
0.28 |
0.31 |
0.37 |
0.21 |
0.15 |
0.34 |
Y9 |
0.14 |
0.12 |
0.26 |
0.39 |
0.33 |
0.31 |
0.24 |
0.18 |
0.26 |
0.14 |
0.09 |
0.22 |
Y10 |
0.26 |
0.28 |
0.36 |
0.37 |
0.35 |
0.18 |
0.26 |
0.28 |
0.16 |
0.21 |
0.14 |
0.11 |
Y11 |
0.34 |
0.21 |
0.19 |
0.34 |
0.31 |
0.19 |
0.21 |
0.19 |
0.24 |
0.37 |
0.42 |
0.11 |
Y12 |
0.39 |
0.26 |
0.28 |
0.25 |
0.18 |
0.17 |
0.44 |
0.25 |
0.16 |
0.21 |
0.14 |
0.11 |
Y13 |
0.16 |
0.2 |
0.26 |
0.39 |
0.33 |
0.14 |
0.11 |
0.18 |
0.24 |
0.35 |
0.33 |
0.21 |
Y14 |
0.26 |
0.18 |
0.3 |
0.17 |
0.35 |
0.19 |
0.08 |
0.33 |
0.34 |
0.245 |
0.31 |
0.11 |
Y15 |
0.16 |
0.14 |
0.09 |
0.22 |
0.21 |
0.35 |
0.21 |
0.25 |
0.25 |
0.35 |
0.14 |
0.15 |
Y16 |
0.32 |
0.11 |
0.08 |
0.24 |
0.21 |
0.25 |
0.3 |
0.35 |
0.45 |
0.25 |
0.14 |
0.11 |
Step 4, according to the pattern density value of each measured described local chip fritter and draw out the two-dimentional contour map of the pattern density of described chip according to the physical location of each described local chip fritter on described chip.Namely draw out the two-dimentional contour map that embodiment of the invention method is as shown in Figure 5 drawn according to data as described in Table 3.In Fig. 5,<=10%,<=20%,<=30%,<=40% and>40% value each mark with different colors, be beneficial to distinguish fast pattern density everywhere on the described chip.
Step 5, according to Fig. 5, find out the graph block greater than 30%, namely find out<=40% and>color block of 40% correspondence, whether the method that adopts manual calculations or programming to calculate is calculated greater than existing area greater than the graph block of described local area in 30% the graph block.Shown in dashed lines circled among Fig. 5, do not satisfy the pattern density standard at coordinate (3,3) to may exist between the coordinate (7,7) and namely exist greater than the described local chip piece with local area size of higher limit 30%.Can obtain the pattern density of two local chip pieces greater than higher limit 30% by calculating, described two local chip pieces are respectively coordinate (4,4) to coordinate (7,7) be that X4~X7, ordinate are local chip piece and the coordinate (4 of Y4~Y7 corresponding to abscissa as described in Table 3 namely, 3) be that X4~X7, ordinate are the local chip piece of Y3~Y6 corresponding to abscissa as described in Table 3 namely to coordinate (7,6).
Step 6, owing to exist two local chip pieces to exceed standard, so described chip design is defective, need to revise design configuration.
By above embodiment as can be known, employing embodiment of the invention method can increase the checking ability of pattern density really, and method directly, simply is not easy to omit the zone of not satisfying pattern density.And the present invention can also avoid too much false alarm occurring owing to dwindling local area.
More than by specific embodiment the present invention is had been described in detail, but these are not to be construed as limiting the invention.In the situation that does not break away from the principle of the invention, those skilled in the art also can make many distortion and improvement, and these also should be considered as protection scope of the present invention.