Figure preprocess method before optical near-correctionTechnical field
The present invention relates to mask pattern design field, the figure pretreatment side before more particularly to a kind of optical near-correctionMethod.
Background technology
In semiconductor manufacturing of the precision below 0.13um technology nodes, the OPC (Optical based on modelProximity Correction, optical near-correction) method be widely used in key level and including ion noteIn the photoetching process for entering, the OPC methods based on model being capable of analogue exposure process (sometimes also include etch) very well by foundationModel, with reference to the pattern cut according to certain rule, the local figure distortion that can be good at completing various complex figures is mendedRepay.
OPC general principles based on model are that original figure is cut into many small fragments by certain rule, and each is smallThere are one or several impact points in fragment, correction pattern fragment is caused by the figure after optical near-correction while in simulationShape analog result is consistent with impact point.
But in original layout, it is understood that there may be some meet design rule but are unfavorable for the figure of optical near-correction,Or in optical near-correction pretreatment process, it is also possible to produce some to be unfavorable for the figure of optical near-correction, such asSmall projection, or small figure breach, these figures do not violate design rule in itself, but the presence of which can cause opticsThe result of near-correction is unreasonable.One of reason is during optical near-correction that these are small raised or small model OPCBreach is so easily caused adjacent normal figure and is unable to reach target as targeted graphical amendment, and the original idea that we correct is simultaneouslyThe unfavorable figures such as above-mentioned small raised or small gap are not needed to reach target.
In traditional OPC handling processes, eliminated using filling graph or figure removal small raised in figure orSmall gap, Fig. 1~Fig. 4 discloses one of processing method, and Fig. 1 is initial target figure, there is small projection, is utilizedThe DRC tool of Mentor companies finds qualified small raised Jog first, as shown in Fig. 2 between Jog and its adjacent side JA into270 ° of angles, the distance relation according to Jog and graph edge JA is formed comprising two minimum rectangle JF on side, as shown in figure 3, merging justBeginning targeted graphical and JF obtain new targeted graphical, as a result as shown in Figure 4.
Because conventional figure projection (Jog in such as Fig. 2) is vertical with graph edge (such as in 90 ° or 270 ° of angles), and withX-axis or Y-axis in the raised adjacent graph edge of the figure and coordinate system utilizes above-mentioned traditional side into 0 ° or 90 ° of anglesMethod can solve conventional figure projection, eliminate the adverse effect to OPC.
But the figure projection on hypotenuse is located at for some, as shown in Fig. 5~Fig. 7, existing DRC tool cannot be directJog graph edge filling regions adjacent thereto are formed, thus can not be solved with traditional processing method.
The content of the invention
The present invention provides the figure preprocess method before a kind of optical near-correction, raised for the figure on hypotenuse, entersRow pretreatment, obtains the targeted graphical eventually for optical near-correction, and so as to eliminate, be unfavorable in this figure optics adjacentThe factor of nearly correction.
To reach above-mentioned purpose, the present invention provides the figure preprocess method before a kind of optical near-correction, for removingIt is unfavorable for the pattern edge of optical near-correction in mask pattern, comprises the following steps：
Step one：One mask pattern is provided, initial graphics are defined as, is found out relative to described in the initial graphicsThe raised short side of the boundary protrusions of initial graphics, then polygon of the selection comprising the raised short side, is defined as the first polygon,The initial graphics are included in first polygon；
Step 2：By first polygon in step one towards the outside mobile of the initial graphics, several are obtainedSecond polygon, wherein the distance for moving is equal to the length of the raised short side, each described second polygon removal is describedInitial graphics obtain several the 3rd polygons；
Step 3：When a line in the 3rd polygon overlaps with the raised short side, by the 3rd polygonThe 4th polygon is defined as, is obtained after all 4th polygons are merged with the initial graphics eventually for carrying out opticsThe targeted graphical of near-correction.
Preferably, in the initial graphics, with horizontal direction as X-axis, in the plane where initial graphics withThe vertical direction of horizontal direction is Y-axis, sets up XY axle two-dimensional coordinate systems, and the initial graphics have hypotenuse, the raised short sideIt is raised relative to the hypotenuse.
Preferably, the hypotenuse and X-axis be at 45 ° or 135 ° of angle, the raised short side with X-axis into 0 ° or90 ° of angles.
Preferably, the length of the raised short side is less than 10nm.
Preferably, the length of the raised short side is 2nm.
Preferably, in step 2 by first polygon respectively along X axis it is right, be moved to the left, then along Y-axisUpwards, move down, respectively obtain four the second polygons.
Preferably, being realized by software Calibre SVRF instruments.
Preferably, the raised short side is on the figure lattice point based on minimum precision.
Compared with prior art, the beneficial effects of the invention are as follows：The present invention provides the figure before a kind of optical near-correctionPreprocess method, is unfavorable for the pattern edge of optical near-correction in mask pattern for removing, and specifically includes three steps：
Step one：One mask pattern is provided, initial graphics are defined as, is found out relative to initial graphics in initial graphicsBoundary protrusions raised short side, then selection comprising the raised short side polygon, be defined as the first polygon, first is polygonInitial graphics are included in shape；
Step 2：By the first polygon in step one towards the outside mobile of initial graphics, several are obtained second polygonShape, wherein the distance for moving is equal to the length of raised short side, by each second polygon removal initial graphics obtain several theThree polygons；
Step 3：It is the by the 3rd polygon definition when a line in the 3rd polygon overlaps with raised short sideFour polygons, obtain eventually for the target figure for carrying out optical near-correction after all 4th polygons are merged with initial graphicsShape.
Graph edge on hypotenuse can be eliminated by above-mentioned steps raised, result uniformity is more after optical near-correctionGood, same target figure is by after optical near-correction, graphic difference is within a minimum figure lattice point.
Brief description of the drawings
Fig. 1 is initial target pictorial diagram in the prior art；
Fig. 2 is enlarged diagram at A in Fig. 1；
Fig. 3 is to form minimum rectangle JF schematic diagrames in the prior art；
Fig. 4 is to obtain targeted graphical schematic diagram in the prior art；
Fig. 5~Fig. 7 is the presence of raised pictorial diagram on hypotenuse；
The initial graphics schematic diagram that Fig. 8 is provided for the present invention；
Fig. 9 is enlarged diagram at B in Fig. 8；
Figure 10 obtains the first polygonal schematic diagram for what the present invention was provided；
Figure 11 is moved along the x-axis and is obtained the second polygonal schematic diagram for what the present invention was provided；
Figure 12 obtains the 3rd polygon and the 4th polygonal schematic diagram for what the present invention was provided according to Figure 11；
The schematic diagram that final goal figure is obtained according to Figure 11 that Figure 13 is provided for the present invention
Figure 14 obtains the second polygonal schematic diagram for what the present invention was provided along Y-axis movement；
Figure 15 obtains the 3rd polygon and the 4th polygonal schematic diagram for what the present invention was provided according to Figure 14；
The schematic diagram that final goal figure is obtained according to Figure 14 that Figure 16 is provided for the present invention；
The figure preprocess method flow chart that Figure 17 is provided for the present invention.
Specific embodiment
To enable the above objects, features and advantages of the present invention more obvious understandable, below in conjunction with the accompanying drawings to the present inventionSpecific embodiment be described in detail.
Figure 17 is refer to, with horizontal direction as X-axis, XY bis- is set up in the direction perpendicular to X-axis as Y-axis on this planeDimension coordinate system, the present invention provides the figure preprocess method before a kind of optical near-correction, unfavorable in mask pattern for removingIn the pattern edge of optical near-correction, comprise the following steps：
Step one：Fig. 8 is refer to, initial target figure Tgt is input into, qualified graph edge projection short side Ja is selected,It is so-called it is eligible refer to the raised short side Ja with coordinate system X-axis into 0 ° or 90 ° of angles, raised short side Ja is relative to initial target figureHypotenuse at 45 ° with X-axis or 135 ° of angle is raised on shape Tgt, and upper with initial target figure Tgt with projection short side Ja phases, respectively into 135 ° and 225 ° of angles, this body length of raised short side Ja is equal to 2nm for adjacent graph edge；Fig. 9 is refer to, all projections are selectedWith coordinate system X-axis into 0 ° of graph edge Jax at angle in short side Ja, select in all raised short side Ja with coordinate system X-axis at an angle of 90Graph edge is Jay；
Step 2：Figure 10 is refer to, all the first polygons comprising raised short side Ja and initial target figure Tgt are selectedPlg；Figure 11 is refer to, the first polygon Plg is moved right 2nm along coordinate system X axis, obtain the second polygon Plgx1；Polygon Plg moves left 2nm along coordinate system X axis, obtains the second polygon Plgx2；Polygon Plg along coordinate system YAxle moves up 2nm, obtains the second polygon Plgy3；Figure 14 is refer to, polygon Plg is moved down along coordinate system Y-axis2nm, obtains the second polygon Plgy4；
According to the polygon that above-mentioned steps are obtained, the polygon obtained after movement is patrolled with initial target figure TgtInverse is collected, Figure 12 and Figure 15 is refer to, obtains, as filled up polygon group in Figure 17, being also the 3rd polygon group Plg_EX1,Plg_EX2, Plg_EX3 and Plg_EX4：
Plg_EX1=Plgx1-Tgt
Plg_EX2=Plgx2-Tgt
Plg_EX3=Plgy3-Tgt
Plg_EX4=Plgy4-Tgt
Step 3：3rd polygon group obtained above, the figure obtained in the 3rd polygon Plg_EX1 of selection and step oneShape side Jax contact polygon for the 4th polygon Plg_F1 (that is have in the 4th polygon Plg_F1 a line be withWhat graph edge Jax overlapped), as shown in figure 12；The polygon that selection polygon group Plg_EX2 is contacted with graph edge Jax is the 4thPolygon Plg_F2, the polygon that selection polygon group Plg_EX3 is contacted with the graph edge Jay obtained in step one is more than the 4thSide shape Plg_F3, the polygon that selection polygon group Plg_EX4 is contacted with graph edge Jay is the 4th polygon Plg_F4, is such as schemedShown in 15；
Figure 13 and Figure 16 is refer to, merges all of 4th polygon that initial target figure Tgt and above-mentioned steps are obtained,Obtain final goal figure Tgt_F=Tgt+ ((Plg_F1+Plg_F2)+(Plg_F3+Plg_F4)).
It is preferred that the above method can be realized by software Calibre SVRF instruments, and raised short side Ja therein is equalThe on the figure lattice point based on minimum precision
Graph edge on hypotenuse can be eliminated by above-mentioned steps raised, result uniformity is more after optical near-correctionGood, same target figure is by after optical near-correction, graphic difference is within a minimum figure lattice point.
Obviously, those skilled in the art can carry out various changes and modification without deviating from spirit of the invention to inventionAnd scope.If these modifications of the invention and modification belong within the scope of the claims in the present invention and its equivalent technologies, thenThe present invention is also intended to including including these changes and modification.