JP2830330B2 - Proximity effect correction method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a proximity effect correction method in pattern formation by direct writing or light exposure of a charged beam in a semiconductor manufacturing process.

2. Description of the Related Art Along with miniaturization and high density of patterns in a semiconductor integrated circuit device, when drawing or exposing a pattern in this way, a charged beam exposure apparatus or an optical reduction projection exposure apparatus is used. Correction for improving the dimensional accuracy of the pattern caused by the proximity effect is indispensable. A common way to compensate for proximity effects is
A pattern is divided into a plurality of elemental figures such as rectangles or triangles, and the desired pattern shape and dimensions can be obtained only by applying an appropriate amount of electron irradiation to each figure or by adding the pattern distortion caused by the proximity effect. For example, there is a method of processing original pattern data in advance. FIG. 16 is a flowchart showing a conventional proximity effect correction method, and FIG. 17 is a view for explaining the method. In FIG. 17, 1 and 2 are the uppermost cell A and the second cell.
In order to perform the above-described proximity effect correction operation, conventionally, FIG. 17 (a) is used to perform the above-described proximity effect correction calculation. ), After inputting the pattern design data having the cell hierarchical structure shown in FIG. 1) to the computer for performing the proximity effect correction operation (STEP 1), the lower cells B and C in this data are expanded on the uppermost cell A. Then, after all patterns have the same hierarchy (STEP 2), as shown in FIG. 17 (b), a plurality of rectangular sub-regions at a dividing line 11 indicated by a broken line are obtained.
Reference frame area divided into zones and having a typical rectangular width h with proximity effect around each sub-zone
12 (area indicated by the dot in the figure) is provided (STEP3),
For each sub-zone, the reference frame area for the pattern included in the sub-zone and for the element figure in the sub-zone of the pattern partially existing in the sub-zone and cut at the sub-zone boundary Perform calculations while taking in the effects of patterns and element figures in
4), a correction effect was obtained (STEP5). (For example, Journal Applied Physics J. Appl. Phys. 50 (19
1979) 4371-4387).

However, in the conventional method, in order to process a large-scale, highly integrated pattern, it is necessary to secure a work file, and a disk capacity for storing a final processing result, In addition, there is a problem that the time required for processing becomes enormous and cannot be used for operation. The present invention has been made in view of the above problems, and suppresses an increase in the amount of processed data.
An object of the present invention is to provide a proximity effect correction method capable of reducing processing time.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an exposure method for producing an exposure pattern on a substrate, comprising: a plurality of cells each including a set of design patterns corresponding to the exposure patterns; For the design data having a hierarchical structure in which the cells have a mutual inclusion relationship, a double nested inner and outer frame region having a width exerted by the proximity effect is set inside the boundary of each cell. Means for reorganizing a cell structure in which a boundary between the inner frame area and the outer frame area is a new cell boundary which replaces the conventional cell boundary; and Means for moving into a cell area and serving as a reference pattern area for performing a proximity effect correction operation on a pattern within the new cell boundary; A frame area serving as a reference pattern area for performing a proximity effect correction operation on a pattern in the immediately higher hierarchical cell; and the cell obtained by subtracting the inside of a new cell boundary of the immediately lower cell from the inside of the new cell boundary. Means for dividing the correction target pattern area into a plurality of sub-zone areas, and means for forming a frame area having a width exerted by the proximity effect around each of the sub-zones and attaching the frame area to the sub-zones Means for preparing for performing the above series of proximity effect correction operations are performed for each cell of each layer from the lowest hierarchical cell to the highest hierarchical cell while maintaining the hierarchical structure of the cells of the design pattern data. A proximity effect correction method comprising: a first means; and a second means for performing a proximity effect correction operation for each of the cells after the first means.

According to the present invention, the operation processing can be performed for each layer and for each cell by the above-described configuration, and for the same cell that exists under a plurality of highest-order cells, regardless of which layer this cell exists in, The proximity effect correction calculation is performed only on one representative cell, and the result may be applied to the same other cell as it is, so that the calculation time can be reduced. In addition, the maximum value of data to be processed at a time is calculated by subtracting the pattern data of all lower cells included in the cell from the sum of the pattern data in a single cell. In order to correct the pattern inside, the maximum amount of the pattern in the double frame that touches the cell boundary within the cell boundary of the immediately lower cell, which is necessary for correcting the pattern in Can be processed by providing a reasonable disk capacity.

Embodiment (Embodiment 1) Hereinafter, an embodiment of a method of correcting a proximity effect that occurs when direct writing is performed using an electron beam will be described. FIG. 1 is a flowchart showing the proximity effect correction means of the present invention;
FIG. 2 is an essential diagram for explaining the present embodiment corresponding to the cell arrangement configuration of FIG. 17 (a).
The figure does not show the patterns 5 to 10 in FIG. 17 (a). First, CAD for patterns with a cell hierarchy
The data is input to a computer for performing a proximity effect correction calculation (STEP 1). Next, a cell table corresponding to the cell hierarchy shown in FIG. 17 (a) given in FIG. 3 is created (STEP 2). In the cell table shown in FIG. 3, the left column is arranged in ascending order from 1 indicating the highest cell to 3 which is the hierarchy corresponding to the cell corresponding to the lowest in the considered cell configuration, and The column shows each cell name corresponding to these hierarchies. When a plurality of identical cells exist when a cell table is created, the lowest hierarchy among the hierarchies in which the same cells exist is registered. In FIG. 17 (a), the cell C exists at two places of the second hierarchy and the third hierarchy. In this example, the cell C is registered as the third hierarchy. In this example, only one cell in each layer exists on the cell table, but a plurality of cells may exist. Next, in STEP3 to STEP11, the pattern processing corresponding to the preparation for performing the proximity effect correction calculation is performed in the lowermost layer NMAX.
Is performed on all the cells registered in the cell table in descending order from the cells existing in the cell table to the cells existing in the uppermost layer 1. First, it is determined whether or not the cell is the highest cell, that is, whether it is a cell of the N = 1 layer. If not, the process proceeds to the following processing (STEP 3).
Let N be the currently considered hierarchy. Then, double frame frames nesting with each other are provided inside the cell boundaries of the cells in the N layers (STEP 4). For each cell, the width of the outer frame area (the area shown by the dots in FIG. 2) surrounded by the cell boundary and the outer frame frame, and the width of the outer frame area and the inner frame frame The width of the inner frame area (the area shown by hatching in FIG. 2) is h, and the size of h adopts a typical length that exerts the proximity effect. The above h is an amount determined according to the conditions such as the electron beam accelerating voltage, the type of register, and the coating thickness, if they are determined. Next, instead of the conventional cell environment, the cell structure in which the outer frame is set as a new cell boundary is reorganized (STEP 5). Further, the outer frame area is a new reference pattern area as a reference pattern area when performing the proximity effect correction calculation on the pattern of the correction target pattern area of the cell by taking into account the effect of the electron beam applied to the pattern in this area. Attach to the cell (STEP 6). Here, the correction target pattern area is an internal area surrounded by a new cell boundary of the cell. However,
When a lower cell exists below the cell, a region obtained by subtracting a region surrounded by a new cell boundary of the cell immediately below from the above-described internal region is a correction target pattern region. After completing steps 3 to 6 for all cells registered in the cell table existing in the considered layer N, the target layer is increased by one (STEP 7). STEP4 to STEP7
Until N = 1, the processing is omitted. Thereafter, for all the cells registered in the cell table of the target hierarchy N-1, the outer and inner frame regions of all the cells of the immediately lower hierarchy N included in each cell are set to the N The cell is expanded to the cell of the -1 layer, and the cell is made the same layer as the cell (STEP 8). Among the parts expanded to the cells of the (N-1) th layer, an operation of transferring the pattern in the cell outer frame region of the immediately lower layer N as a pattern in the cell of the (N-1) th layer is performed (STEP 9). And,
The pattern in the frame area inside the cell of the immediately lower layer N is attached to the cell of the N-1 layer as a reference pattern area for the correction target pattern area of the cell of the N-1 layer (STEP 10). As a result of the operations from STEP 4 to STEP 10, the frame region outside each cell becomes a reference pattern region for correction of a pattern within a new cell boundary, and at the same time, is duplicated as a pattern of the immediately upper cell. It has the dual character that the frame area inside each cell is a pattern within the new cell boundary and also serves as a reference pattern area when correcting the pattern of the cell immediately above it. become. As a result, by the operations from STEP 4 to STEP 10, one pattern file is created for each different new cell. FIG. 4 is a diagram for explaining this. That is, in the example shown in FIG. 3A where the cell H of the Nth hierarchy exists as the lower cell inside the cell G of the N-1th hierarchy, 169 is a cell boundary of the cell G, and 170 is a cell boundary.
Is a frame frame outside the cell G, 171 is a cell boundary of the cell H, 172 is a frame frame outside the cell H, 173 is a frame frame inside the cell H, and 174 is a frame area outside the cell G. Note that 170 coincides with the cell boundary of the new cell G 'for the cell G, and 172 coincides with the cell boundary of the new cell H' for the cell H. 175 is a region obtained by excluding a region within the cell boundary of cell H 'from within the cell boundary of cell G', 176 is a frame region outside cell H, 77 is a frame region inside cell H, and 78 is a frame region inside cell H 3 shows an area within the frame. FIG. 4 (b) shows a pattern file 79 associated with cell G 'for the cell configuration of FIG. 4 (a). The pattern file 79 is composed of four pattern subfiles. That is, the pattern subfile 80 in the reference pattern area 74 of the cell G ', the pattern subfile 81 in the area 75 to be the actual pattern to be corrected of the cell G', and the cell to be incorporated as the actual pattern to be corrected of the cell G ' The pattern sub-file 82 in the frame area 76 outside the lower cell H of G, and the pattern file in the pattern sub-file 83 in the frame area 77 inside the lower cell H of the cell G, which becomes the reference pattern area for the cell G '. 79 are composed. Regarding the same cell that exists under the highest cell, no matter what layer this cell is in, only one cell in the cell located in the lowest layer where this cell exists is in STEP4. From 1
If the processing up to 0 is performed and this is registered as the pattern file 79, the result can be applied to the same cell in other same layers and different layers. For each correction target pattern area of the sub-file 181 in FIG. 4 (b) in FIG.
Each sub-zone is divided into zones, and a reference frame having a width h, which is a reference pattern area used for correcting a pattern in the sub-zone, is provided around each sub-zone boundary (STEP 11). Here, the width h of the reference frame attached to the sub zone is the same as the frame area width h inside and outside the cell. This is necessary in the sense that a region that captures the effect of a close pattern is made consistent in a series of operations. However, the series of arithmetic processing may be different. The size of the sub-zone is determined based on the processing efficiency, calculation accuracy, and the like. There is no problem even if the size of each sub-zone is different for each cell as long as the above-mentioned points are considered. The series of processing from STEP 4 to STEP 11 only needs to be performed once for the same cell, and can be applied to the same cell arranged on the same layer and another layer. Hereinafter, the operations from STEP 3 to STEP 11 will be described in detail with reference to the drawings. By the operations so far, in FIG. 2, 13 and 14 indicate the outer and inner frame frames of the cell B, respectively, and 15 and 16 indicate the lower cell C immediately below the cell B, respectively.
And 17 and 18 indicate the outer and inner frame frames of the lower cell C immediately below the cell A, respectively. The cell C, which is a lower cell of the cell B, becomes a new cell C 'having a cell boundary of 15, and the pattern of the outer frame area 21 in the cell C is incorporated into the upper cell B, and the cell B has 13 It becomes a new cell B 'as a cell boundary, and the pattern of the outer frame area 19 in the cell B is incorporated into the uppermost cell A. Cell C ', and the pattern of the outer frame area 23 in the cell C is the upper cell A
Is incorporated as a pattern. For the cell A, the frame area 20 inside the cell B and the frame area 24 inside the cell C immediately downstream of the cell A are attached to the cell A as a reference pattern area, and for the cell B ', the cell B
The frame area 22 inside the cell C, which is a lower cell of, is attached to the cell B 'as a reference pattern area. Fig. 5 (a)
FIG. 17 is a diagram showing a relationship of a hierarchical structure of cells corresponding to FIG. 17 (a). FIG. 5 (b) is a diagram showing a hierarchical structure as a result of the reorganization of the cell structure according to the present invention. A change as shown in FIG. 5B occurs due to a change in the cell environment of the lower cells B and C except for the highest cell A. FIG. 6 is a diagram for explaining the above situation by taking out the cell C 'which is a lower cell of the cell B'. Since no lower cell exists in the cell C ', the boundary 15
Is divided into rectangular sub-zones of an appropriate size, and a frame area having a width h is provided around each sub-zone. In this figure, a typical sub-zone 30 shown with diagonal lines
And 31, the reference frame area and
33 are arranged. In practice, reference frame areas are arranged for all sub zones. The reference frame area 32 of the sub zone 30 in contact with the cell boundary 15 overlaps a part of the area 22. Reference numeral 29 denotes a dividing line for forming a sub-zone. FIG. 7 is a diagram illustrating the above-described situation by taking out the cell B '. Border 13 of cell B '
The pattern area to be corrected, which is surrounded by the boundary 15 of the lower cell C 'and the lower cell C', is divided into rectangular sub-zones of an appropriate size, and a frame having a width h is provided in the enclosure. Representative subzones 36,37
And reference frame areas 39, 40
And 41 are arranged. In practice, reference frame areas are arranged for all sub zones. Cell boundary
The reference frame area 39 of the sub zone 36 contacting the part 13 overlaps a part of the area 19, and the reference frame area 40 of the sub zone 347 contacting the boundary 15 of the lower cell C ′ overlaps a part of the area 22. Reference numeral 42 denotes a dividing line for forming a sub zone. Hereinafter, an example in which the proximity effect is corrected by optimizing the exposure amount to be given to the explanation pattern for each pattern will be described (STEP 12). In FIG. 2, the initial estimation of the zero-th approximation is performed on a pattern existing in the external reference frame area 21 of the lowest cell C 'which is a lower cell of the cell B' or an element figure generated by dividing the pattern. The dose Q _init is given. In addition,
In this figure, the pattern is omitted. Where Q _init
Depends on the exposure parameters such as the electron beam acceleration voltage, the type of resist, and the coating thickness, and may be set to an approximate value obtained from conventional experimental experience. Based on this value, a correction operation is performed for each of the sub-zones belonging to each of the sub-zones in the cell C 'shown in FIG. 6 to determine the exposure amount for each of the sub-zones. . At this time, for the pattern in the reference frame area attached to each sub zone, the estimated value Q _init is given equally, or the adjacent sub
For the pattern in the reference frame area overlapping with the pattern in the zone, the corrected exposure amount is given. The correction operation for the pattern in the lower cell C 'immediately below the cell A given by the cell boundary 17 shown in FIG. 2 is performed in the cell C' in the lower cell of the cell B 'and surrounded by the cell boundary 15. It is sufficient that the result for the pattern is used as it is, and there is no need to perform a new correction operation. Next, the second
In the case of the cell C 'for all the patterns in the area obtained by subtracting the inside of the boundary 15 of the cell C' from the inside of the cell boundary 13 of the cell B 'shown in FIG. The correction calculation is performed for each sub-zone in the same manner as described above.
Finally, for the uppermost cell A, all the patterns inside the cell A except for the inside of the boundary 13 of the cell B 'and the inside of the boundary 17 of the cell C' shown in FIG. , A correction calculation is similarly performed for each sub-zone. In a series of operations from the cell C ′ to the cell A, the first time is calculated by assuming an estimated exposure amount Q _init for a pattern in the reference frame area. By updating and providing the exposure amount obtained in the previous series of operations, this series of operations is performed a plurality of times as necessary. In other words, a plurality of representative patterns that well represent the convergence of the solution of a series of iterative calculations within the reference frame area or sub-zone, and a series of corrections for each pattern as needed Monitor the amount of exposure determined through calculation, Until the E value defined by becomes smaller than the threshold value E _crit
Perform a series of operations repeatedly. Here, i is a sign indicating a specific pattern, m is the total number of patterns to be monitored,
n represents the number of repetitions of a series of operations. E _crit depends on exposure conditions and required correction accuracy. In this case, STEP
The proximity effect correction calculation in 12 need only be performed once for the same cell, and can be applied to the same cell arranged in the same hierarchy and another hierarchy. In addition, although the processing is sequentially performed from the lower cell to the upper cell, the processing may be started from any cell registered in the cell table. After completing the proximity effect correction calculation for all the cells registered in the cell table by the operations up to STEP 12, each of the cells for which the proximity effect correction has been completed for all the cells under the highest cell A Apply the cell operation result and complete the operation (STEP1
3).

(Embodiment 2) FIG. 8 is a flowchart showing an embodiment in the case where a cell having an array structure is present, and FIG. 9 is a main view for explaining the present embodiment. First, CAD data of a pattern having a hierarchical structure of cells including cells having an array structure is input to a computer for performing a proximity effect correction operation (STEP 1). Next, as in the case of the first embodiment, a cell table corresponding to the design data shown in FIG. 9 is created (STEP 2). Next, the pattern processing corresponding to the preparation for performing the proximity effect from STEP 3 to STEP 11 is performed on each array element cell in the cell having the array structure, the cell having the array structure, and the cell including the array structure. Perform for upper cell. First, FIG. 9 shows a case where a cell E in which the same element cells F50 to 61 form a 4 × 3 array exists below the uppermost cell D. Within each element cell F is a pattern 64.
Here, reference numeral 43 denotes a cell boundary of the uppermost cell D, and reference numeral 44 denotes a cell boundary of the cell E formed in the array. The array element cells F in the cell E are classified into nine groups (STEP 9).
3). That is, the group G _{C of} the internal array element cells 60 and 61 not in contact with the boundary of the cell E, the upper left end 50, the upper right end 53,
G _TL , G _TR , G located at the lower left corner 58 and the lower right corner 55, respectively
_BL and G _BR groups, 51,52 groups located at the top
Group G _B of G _T, located at the lower end 56 and 57, a group G _L and G _R positioned at the left end 59 and right 54. For the array elements cell F60,61 belonging to the group G _C, its elementary cells regarded as one sub-zone is defined by the reference frame edge 62 Kakowari of the boundary with respect to one representative array element cell 60 A reference frame area 63 is provided (STEP 4). Double inner and outer frame frames are alternately nested inside the cell boundaries of the cells E formed by the array (ST
EP5). Here, 45 indicates the outer frame frame, and 46 indicates the inner frame frame. In the cell E constituted by the array, the width of the outer frame area 47 (area indicated by dots) surrounded by the cell boundary 44 and the outer frame frame 45, and the outer frame frame 45 and the inner frame The width of the inner frame region 48 surrounded by 46 is defined as h, and the size of h adopts a typical distance that exerts the proximity effect. The structure for setting the outer frame 45 as the cell boundary of the new cell E 'instead of the conventional cell boundary 44 is reorganized (ST
EP6). Of the array element cells F, groups G _TL ,
For cells associated with G _TR , G _BL , G _BR , G _T , G _B , G _L and G _R ,
Each element cell area is cut at the outer frame 45 of the cell E, which is the boundary of the cell E ', and a portion 47 indicated by a dot is deleted, and each group is replaced with a new cell F _TL replacing the conventional element cell F. _{, F TR, F BL, F} BR, F T, F B, to reconstruct as F _L and F _R (STEP7). The process of expanding the frame regions 47 and 48 outside and inside the cell E constituted by the array into the cell D is performed to make the cell D the same level as the cell D (STEP 8). However, in this embodiment, the cell D is set as the highest cell. However, if the cell D is not the highest cell, the processing from STEP3 to STEP10 in FIG. 1 is different as described in the first embodiment. This is performed for all cells up to the highest cell. The frame area outside the cell E in the part expanded to the top cell D
The operation in which the pattern in 47 is performed as the pattern in the cell D is performed (STEP 9). The pattern in the frame area 48 inside the cell E is attached to the cell D as a reference pattern area for the correction target pattern area of the cell D (STEP 10). The pattern area to be corrected excluding the inside of the new cell boundary 45 of the lower cell E composed of an array from the inside of the boundary 43 of the top cell D is divided into a plurality of sub zones, and Set a frame area around the zone with the width of the proximity effect (STEP 11). Hereinafter, a case where the proximity effect is corrected by optimizing the exposure amount to be given to the design pattern for each pattern as in the case of the first embodiment will be described. The proximity effect correction operation is performed on the design pattern including the cell having the array structure shown in FIG. 9 as follows (step 12). That is, first the representative cell 60 belonging to the inner G _C array element cells, the elements figures generated by dividing the existing pattern or pattern, in the reference frame area 63 associated therewith, the exposure of the zero approximation A quantity Q _init is given, and a proximity effect correction calculation is performed on the pattern within the cell boundary of the representative cell 60 based on the quantity Q _init . Next, the top cell D
For each of the sub-zones,
6 and 7 for the pattern in the sub zone area.
A correction operation is performed in the same manner as in the example in the figure (STEP 13). STEP
A series of correction operations in step 12 and step 13 are repeatedly performed until E becomes smaller than the threshold value E _{crit as} described above. Then apply equivalently to the performed proximity effect correction calculation results of all the array elements cell belonging to other G _C (array element cell 61 in this example) with respect to the representative cell 60 in the cell having the array structure . Next Group _{G TL, G TR, G BL} , G BR, G T, G B, G L and
G for all array elements cell belonging to _R, the cell F _TL is overlapped portion excluding the dot region 47 is a portion of the outer frame region of each element between cells E, F _TR, F
_{BL, F BR, F T,} F B, relative to the area of the F _L and F _R, applying a correction calculation result obtained in G _C. Thus, the calculation is completed (STEP 14).

(Embodiment 3) FIG. 10 is a flowchart showing an embodiment different from Embodiment 2 when cells having an array structure are present.
The figure is a view for explaining the embodiment. First, CAD data of a pattern having a hierarchical structure of cells including cells having an array structure is input to a computer for performing a proximity effect correction operation (STEP 1). Next, as in the case of the first embodiment, a cell table corresponding to the design data shown in FIG. 11 is created (STEP 2). Next, pattern processing corresponding to the preparation for performing the proximity effect from STEP 3 to STEP 11 is performed for each array element cell in the cell having the array structure.
This is performed for the cell having the array structure and the uppermost cell including the cell having the array structure. First, the eleventh
In the figure, the same element cell F5 is located below the uppermost cell D.
Cell E in which 0 to 61 are formed in a 4 × 3 array
Shows the case where exists. In each element cell F,
There is a pattern 64. Here, reference numeral 43 denotes a cell boundary of the uppermost cell D, and reference numeral 44 denotes a cell boundary of the cell E formed in the array. The array element cells F in the cell E are classified into two groups (STER3). That is, a group G _{C of} the internal array element cells 60 and 61 not in contact with the boundary of the cell E, and a group _GP of the other peripheral array element cells 50 to 59. For the array elements cell F60,61 belonging to the group G _C, it considers the elementary cells and one sub-zone, defined for one representative array element cell 60 in the reference frame frame 62 the boundary Kakowari A reference frame area 63 is provided (STEP 4). For the peripheral array element cells F50 to F59 belonging to the group _GP , double inner and outer frame frames nesting with each other are provided inside the cell boundary of each array element cell (STEP 5). FIG. 11 illustrates the situation of only the representative array element cell 53. That is, 67 indicates the outer frame frame, and 68 indicates the inner frame frame. The width of the outer frame area 65 (area indicated by dots) surrounded by the sub-zone boundary and the outer frame frame 67, and the inner frame surrounded by the outer frame frame 67 and the inner frame frame 68 The width of the region 66 is defined as h, and the size of h adopts a typical distance exerting the proximity effect. Instead of the conventional cell boundary, the cell structure in which the outer frame 67 is set as a new cell boundary and the cell F is registered as the cell F 'is reorganized (STEP 6). Also,
The pattern in the outer frame area 65 is recognized as a reference pattern when performing the proximity effect correction calculation on the pattern in the new cell boundary (STEP 7). Next, a process of expanding the outer and inner frame regions into the cell D is performed, and the same hierarchy as that of the cell D is used (STEP 8). However, in this embodiment, the cell D is set as the highest cell. However, when the cell D is not the highest cell, as described in the first embodiment, the cell D in FIG.
The processing from STEP 2 to STEP 10 is performed for all different cells up to the highest cell. The pattern in the outer frame area 65 in the portion expanded to the uppermost cell D is subjected to an operation of being incorporated as a pattern in the cell D (STEP 9). In addition, the pattern in the inner frame area 66 is attached to the cell D as a reference pattern area for the correction target pattern area of the cell D (STEP 10). STEP
Processing from 5 to STEP10 is carried out for only one representative cell F 'belonging to the G _P, the result may be applied equivalently to other array elements cell belonging to G _P. Top cell D
, The area inside the cell boundary of the internal array element cells F60 and 61 in the cell E, and the area inside the frame outside the peripheral array element cells F50 to 59 in the cell E. The pattern area to be corrected of the uppermost cell D from which the area is deleted is divided into a plurality of sub-zones, and a frame area having a width exerting the proximity effect is set around each sub-zone (STEP 11). Hereinafter, a case where the proximity effect is corrected by optimizing the exposure amount to be given to the design pattern for each pattern as in the case of the first embodiment will be described. The proximity effect correction operation is performed on the design pattern including the cell having the array structure shown in FIG. 11 as follows. That is, first the array element cell, relative to a typical internal array elements cell 60 belonging to the G _C, pattern exists in the reference frame area 63 associated therewith, or pattern element shapes that are generated by dividing the , The exposure amount Q _init of the zeroth approximation is given, and the proximity effect correction is performed on the pattern in the sub-zone area based on the exposure amount Q _init (STEP 12). next. With respect to the representative peripheral array element cells 53 belonging to the _GP , the reference pattern area, that is, the pattern existing in the outer frame area 65, or the zeroth approximation exposure to the element figure generated by dividing the pattern. The quantity Q _init is given, and the proximity effect correction calculation is performed on the pattern inside the new cell boundary 67 based on the quantity Q _init (STEP 13). Next, a correction operation is performed on the pattern in the sub-zone area for each sub-zone for the correction target pattern area of the top cell in the same manner as in the example of FIGS. 6 and 7 (STEP 14). ). A series of correction operations STEP12～STEP14, as described above is repeated until E is less than the threshold value E _crit. Above, the proximity effect correction calculation results made to typical array element cells 60 belonging to the G _C, equivalent to all array elements cell belonging to other G _C (array element cell 61 in this example) applied I do. Then a proximity effect correction calculation results made to a typical array element cells 53 belonging to the G _P, the array element cell 50 to 52 and 54 to the all array elements cell (this example belonging to other G _P The same applies to 59). Thus, the calculation is completed (STEP 15).

(Embodiment 4) FIG. 12 is a flowchart showing an embodiment different from Embodiments 2 and 3 in the case where a cell having an array structure is present, and FIGS. 13 to 15 are essential diagrams for explaining the present embodiment. It is. First, CAD data of a pattern having a hierarchical structure of cells including cells having an array structure is input to a computer for performing a proximity effect correction operation (STEP 1). Next, as in the case of the first embodiment, a cell table corresponding to the design data shown in FIG. 13 is created (STEP 2). Next, STE
The pattern processing corresponding to the preparation for performing the proximity effect from R3 to STEP11 is performed by performing each array element cell in the cell having the array structure, the cell having the array structure, and the top cell including the cell having the array structure Perform for First, FIG. 13 shows a case in which a cell E in which the same element cells F50 to 61 form a 4 × 3 array exists below the uppermost cell D. There is a pattern 64 in each element cell F. Here, reference numeral 43 denotes a cell boundary of the uppermost cell D, and reference numeral 44 denotes a cell boundary of the cell E formed in the array. Double inner and outer frame frames nesting with each other are provided inside the cell boundaries of the cells E formed by the array (STEP 3). Here, 45 indicates the outer frame frame, and 46 indicates the inner frame frame. In the cell E constituted by the array, the width of the outer frame area 47 (area indicated by dots) surrounded by the cell boundary 44 and the outer frame frame 45, and the outer frame frame 45 and the inner frame Inner frame area 48 surrounded by frame 46
Is the width of h, and the size of h adopts a typical distance exerting the proximity effect. The cell structure for setting the outer frame 45 as the cell boundary of the new cell E 'instead of the conventional cell boundary 44 is reorganized (STEP 4). The array element cell F in the cell E is reconfigured using four types of new element cells S, T, U and W. FIG. 14 shows this reconstruction method. 70 is a cell boundary of the array element cell F. First
Width P _x shown in FIG. 14 (a), the elementary cells F height P _y, width h, the area s ₁ having a height h located in the upper left corner 72 of the array element cell, located in the lower left corner 73 A region s ₂ having a width h and a height h, and a region having a width h and a height h located at the lower right corner 74
s ₃ , an area s ₄ having a width h and a height h located at the upper right corner 75,
Width located 76 between the left corner of the s ₁ and s ₂ h, the height P _y -2 × h
, A region t ₂ having a width h located at 77 in the right corner between s ₃ and s ₄ , a height _Py −2 × h, and a region t ₂ between s ₁ and s _{4 in} the upper corner. A region u ₁ having a width P _x −2 × h and a height h located at
A region u ₂ having a width P _x −2 × h, a height h located at 79 between s ₂ and s _{3 in the} lower corner and s ₁ , t ₁ , s ₂ , u ₂ , s ₃ , t in the center _2, s ₄ and divided into nine regions in the area w at the position of 80 surrounded by u _1. Reference numeral 71 denotes a dividing line for distinguishing these nine areas. Next, for example, 60 array element cells F located at the center of FIG. 13 are considered as target element cells. The area s ₂ of the target element cell 73 and the area s ₃ of the element cell F existing adjacent to the left side of the target element cell 74
When the four regions of the region s ₁ and the target element cell and the lower left corner of the of that element cell F which is in contact at one point 75 of area s ₄ elements cell F of 72 present below and in contact with the target element cell A cell S is created by combining as shown in FIG. 14 (b). 81 is the boundary of this cell S. Next, the a region u ₁ of the target element cells 78, 79 second regions in the region u ₂ of the elements present cell F in contact on said target element cell, as shown in FIG. 14 (b) The cells are combined to create a cell U. 83 is the boundary of this cell U. Next, the region t ₁ of 76 of the target element cell and the region t ₂ of 77 of the element cell F existing to the left of the target element cell
Are combined as shown in FIG. 14 (b) to create a cell T. 82 is the boundary of this cell T. Finally, the area w of the target element cell 80 is registered as a cell W as shown in FIG. 14 (b) (STEP 5). Cell E '
The cell boundary is reconfigured using the new element cells S, T, U and W as shown in FIG. 15 (STEP 6). here
Reference numeral 85 denotes a cell environment of cells S, T, U and W. Then these 4
For each of the type array element cells, one is extracted as a representative array element cell, and a reference frame area is provided around the cell boundary (STEP 7). In FIG. 15, 8
6, 87, 88 and 89 are representative element cells of cells S, T, U and W, respectively, and 90, 91, 92 and 93 are reference frame areas of representative element cells S, T, U and W, respectively. . The process of expanding the outer and inner frame regions 47 and 48 of the cell E composed of the array into the cell D is performed to make the same level as the cell D (STEP
8). However, in this embodiment, the cell D is set as the highest cell. However, if the cell D is not the highest cell, the processing from STEP3 to STEP10 in FIG. 1 is different as described in the first embodiment. This is performed for all cells up to the highest cell. Among the parts expanded to the uppermost cell D, the pattern in the frame area 47 outside the cell E is subjected to an operation of being incorporated as a pattern in the cell D. (STEP9). And,
The pattern in the frame area 48 inside the cell E is the cell D
Is attached to the cell D as a reference pattern area for the correction target pattern area (STEP 10). The pattern area to be corrected excluding the inside of the new cell boundary 45 of the lower cell E composed of an array from the inside of the boundary 43 of the top cell D is divided into a plurality of sub zones, and Place a frame with a proximity effect width around the zone (STEP1
1). Hereinafter, a case will be described in which the proximity effect is corrected by optimizing the exposure amount for providing the design pattern for each pattern, as in the case of the first embodiment. The proximity effect correction operation is performed on the design pattern including the cell having the array structure shown in FIG. 13 as follows. That is, first, for each of the representative array element cells S, T, U, and W, 86, 87, 88, and 89, the patterns or patterns existing in the reference frame areas 90, 91, 92, and 93 associated with them are In the element figure generated by dividing,
The exposure amount Q _init of the zeroth approximation is given, and the proximity effect correction operation is performed on the pattern in the cell environment of each of the representative cells 86, 87, 88 and 89 based on this (STEP 12). Next, a correction operation is performed on the pattern in the sub-zone area for the correction target pattern area of the uppermost cell D in the same manner as in the examples of FIGS. 6 and 7 (STEP 13). STEP12 and ST
As described above, a series of correction operations of EP13 is performed by setting E to a threshold value E _crit
Repeat until smaller. Next, the result of the proximity effect correction operation performed on each of the representative cells 86, 87, 88, and 89 in the cell having the array structure is applied to all of the other element cells S, T, U, and W. Applies equivalently to array element cells. Thus, the calculation is completed (STEP 14).
As described above, in the first, second, third and fourth embodiments, since the arithmetic processing is performed for each layer and for each cell, the arithmetic processing is performed after the conventional hierarchy of all cells is expanded. As compared with the case of performing the above, the amount of processed data per operation is reduced, and the required work file capacity is reduced. Furthermore, for the same cell in the design data, no matter at what level they exist, this is equivalent to preparing to perform the proximity effect correction operation only on the representative representative cell in the same cell group. Since the pattern processing and the proximity effect correction calculation are performed and the result can be equally applied to the same other cells, the calculation processing time is significantly reduced. Also,
When the arrangement of the pattern in the cell has a two-dimensional periodicity with respect to the cell having no array structure, the cell is reconfigured as a set of a plurality of array element cells. Later, the second, third and fourth embodiments can be applied. Further, in the second, third and fourth embodiments, when the size of the array element cell is too large as one processing unit, the inside of the array element cell is further divided into a plurality of sub-zones, Sub-elements in the array element cell
It is also possible to add and implement a means for correcting for each zone. In the first, second, third and fourth embodiments, the case where the number of cell layers of the design data is a maximum of three has been described. Also, the present invention can be similarly applied to a case where a plurality of types of arrays and a plurality of cells including an array exist in an arbitrary hierarchy. Also,
In the present embodiment, the method of adjusting the exposure amount to be irradiated to each pattern to an optimum value is used. However, this method is used to adjust the shape and size of the pattern or the element graphic to the optimum value. Even if it changes, it is possible to implement similarly. Further, although the present embodiment has been described only for direct writing with an electron beam, this is a proximity effect correction method which can be similarly applied to a proximity effect phenomenon occurring at the time of writing with an ion beam and exposure with light.

Advantageous Effects of the Invention As is apparent from the above description, according to the present invention, for design data having a hierarchical structure of cells, while maintaining the hierarchical structure, the proximity effect is obtained for each hierarchy and for each cell. By performing the correction operation, the amount of data to be processed at one time is reduced, and the pattern data of a large-scale VLSI chip can be processed in a short time using a reasonable amount of magnetic disk resources. Furthermore, for the same cell in the design data, no matter at what level they exist, this is equivalent to preparing to perform the proximity effect correction operation only on the representative representative cell in the same cell group. Since the pattern processing and the proximity effect correction calculation processing are performed and the result can be equally applied to the same other cells, the calculation processing time is significantly reduced. As described above, the present invention has an enormous effect in correcting the proximity effect.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the arithmetic processing in the first embodiment of the present invention, FIG. 2 is a cell layout diagram for explaining the present embodiment, and FIG. 3 is a cell table for explaining the present embodiment. FIG. 4, FIG. 4 is a diagram for explaining a pattern file, FIG. 5 is a diagram showing a cell hierarchy structure of the present embodiment, and FIGS. 6 and 7 are diagrams for explaining FIG. 2 in detail. FIG. 8, FIG. 8 is a flowchart showing the operation processing for the array cells in the second embodiment of the present invention, FIG. 9 is a cell layout diagram for explaining the present embodiment, and FIG. 10 is a third embodiment of the present invention. FIG. 11 is a flowchart showing an operation process for an array cell in the embodiment, FIG. 11 is a cell layout diagram for explaining the present embodiment, FIG. 12 is a flowchart showing an operation process for an array cell in a fourth embodiment of the present invention,
FIG. 13 is a cell layout diagram for explaining the present embodiment, FIG. 14 is a diagram showing a method for reconfiguring array element cells for explaining the present embodiment, and FIG. 15 is a diagram for explaining the present embodiment. Fig. 16 shows the reconstructed element cells, and Fig. 16 shows the conventional sub-zone
FIG. 17 is a flow chart showing processing by the frame method, and FIG. 17 is an arrangement diagram for explaining the conventional sub-zone frame method. 1 ... the cell boundary of the highest cell A, 2 ... the cell boundary of the cell B of the second hierarchy, 3, 4 ... the cell boundary of the cell C, 13 ... the outer frame within the cell B (cell B ' Cell boundaries), 14…
... inner frame within cell B, 15, 17 ... outer frame within cell C (cell boundary of cell C '), 16, 18 ...
Inner frame in cell C, 19 ... Outer frame in cell B (external reference frame in cell B '), 20
... The inner frame area in cell B (cell B 'of cell A)
, An inner frame area in cell C, 22, 24 an inner frame area in cell C, 29 a dividing line for forming a sub-zone, 30 , 31 …… Sub zone inside area, 32,33 …… Sub
Reference frame area attached to the zone, 36 to 38
Inside area of zone, 39 to 41... Reference frame area associated with sub-zone, 42... Dividing line for forming sub-zone, 43... Cell boundary of top cell D, 44.
Boundary of cell E composed of 3 element cells F, 45 ...
The outer frame within cell E (boundary of cell E '), 46 ...
... Inner frame within cell E, 47... Outer frame area within cell E (external reference frame area for cell D of cell E ′), 48. Internal reference frame area for cell E '),
49: a dividing line that gives a boundary of the element cell F; 62: a frame attached to the internal array element cell F; 63: a reference frame area of the internal array element cell F; 64: inside the array element cell F , Pattern 65, surrounding array element cell F
(Outer reference frame area of cell F ′), 66... Frame area inside the peripheral array element cell F, 67... Frame frame outside the peripheral array element cell F, 68. .., The boundary of the array element cell, 71... A dividing line for dividing the array element cell into nine regions, 72... At the upper left corner in the array element cell A region s ₁ , 71 having a width h located at a height h, a width h located at a lower left corner in an array element cell,
Areas s ₂ , 74 having a height h, width h located in the lower right corner in the array element cell, areas s ₃ , 75 having a height h, width h located in the upper right corner in the array element cell, Area with height h
s ₄ , 76… width h, height located at the left corner in the array element cell
P _y -2 × region t ₁ with h, 77 ...... width located right corner of the array element cell h, region t ₂ having a height P _y -2 × h, 78
... A region u ₁ having a width P _x −2 × h and a height h located at the upper corner in the array element cell, 79... A width P _x −2 × h and a height located at the lower corner in the array element cell Area u ₂ , 80... Having a height h, width P _x −2 × h, height _Py − located at the center in the array element cell
Region w having 2 × h, 81... Boundary of cell s created by combining regions s ₁ , s ₂ , s ₃ and s ₄ , 82... Cell created by combining regions t ₁ and t ₂ B boundary of T, 83 Boundary of cell U obtained by combining regions u ₁ and u ₂ , 84 Boundary of cell W created using region w, 85 Boundary of cells S, T, U and W , 86 ...
... Representative element cell of cell S, 87 ... Representative element cell of cell T, 88 ... Representative element cell of cell U, 89 ... Representative element cell of cell W, 90 ... Reference frame area of representative element cell S,
91: Reference frame area of representative element cell T, 92: Reference frame area of representative element cell U, 93: Representative element cell W
..,... 169... Cell boundaries of cell G in the (N−1) th hierarchy, 170.
171... Cell boundary of N-th layer cell H, 172
…… frame frame outside cell H (cell boundary of cell H ′), 173… frame frame inside cell H, 174… frame area outside cell G, 175… cell boundary of cell G ′ 176 excluding the area within the cell boundary of cell H ′,
... frame area outside cell H, 177 ... frame area inside cell H, 178 ... area inside frame frame inside cell H, 179 ... pattern file attached to cell G ', 180 ... ... pattern subfile in area 174, 181 ...
… Pattern subfile in area 175, 182… area 176
183: Pattern subfile of area 177.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kenji Kawakita 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-1-245522 (JP, A) JP-A-59- 167018 (JP, A) JP-A-2-130815 (JP, A) JP-A-2-2110 (JP, A) JP-A-2-210814 (JP, A) JP-A-61-21215 (JP, A) JP-A-1-270317 (JP, A) JP-A-59-61131 (JP, A) JP-A-63-17526 (JP, A) JP-A-61-284921 (JP, A) JP-A-60-41220 (JP, A) JP-A-62-86718 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/027 G03F 7/20 504 G03K 7/20 521

Claims (10)

(57) [Claims] 1. A method of performing proximity effect correction on a design pattern having a hierarchical structure of cells when exposing a resist applied and formed on a substrate using a charged beam or light. Means for providing a first frame area having a predetermined width inside the cell, means for providing a second frame area having a predetermined width inside the first frame area, and pattern data in each of the cells. When the proximity effect correction is performed, a pattern in the second frame area and a pattern inside the second frame area are set as correction target patterns, a pattern in the first frame area is set as a reference pattern, and When performing the proximity effect correction on the pattern of the cell immediately above the respective cells, the pattern in the first frame region in each of the cells is subjected to the correction target pattern. Added as over emissions, and using the pattern of the second frame area of the in each cell in the reference pattern, the proximity effect correction method having means for performing proximity effect correction calculation. 2. The method according to claim 1, wherein a proximity effect correction operation is performed on one of the plurality of identical cells, and the result is applied to the other identical cells.
2. The proximity effect correction method according to item 1. 3. A cell according to claim 1, wherein, with respect to a cell having an array structure having an element cell as a basic unit, a peripheral element cell in contact with a boundary of the cell having the array structure is excluded from the cells having the array structure. Means for providing a frame region having a predetermined width outside the boundaries of the element cells for all the element cells;
When the proximity effect correction is performed on the data, the proximity effect correction calculation is performed by using all the pattern data in the element cell as a correction target pattern and using the pattern data in a frame area provided outside the element cell as a reference pattern. Proximity effect correction method comprising means. 4. The method according to claim 1, wherein, for a cell having a predetermined size, the first pattern is applied to all patterns except for a pattern in a first frame area provided inside a boundary of the cell. The area inside the frame area is
Dividing into sub-zones, providing a third frame area having a predetermined width outside the boundary of each of the sub-zones, and setting all pattern data in each of the sub-zones as correction target patterns; A proximity effect correction method including means for performing a proximity effect correction operation using a pattern in a frame area as a reference pattern. 5. When exposing a resist applied on a substrate using a charged beam or light, a cell having the array structure is subjected to proximity effect correction with respect to a design pattern including the cell having the array structure. In the method performed, the element cell is divided into nine 3 × 3 rectangular areas,
Of the four element cells that are in contact with each other, the four different rectangular areas at the corners of each element cell are aggregated to form a second cell, and the side of each of the element cells of the two element cells that are in contact with each other on one side Means for assembling the two different rectangular areas at corners to form third and fourth cells; and defining the rectangular area at the center of the element cell as a first cell;
Means for providing a frame region having a predetermined width outside the boundaries of the second, third, and fourth cells;
In performing the proximity effect correction on the pattern data in each of the third and fourth cells, all the pattern data in each of the first, second, third, and fourth cells are used as correction target patterns, and the first 2. The proximity effect correction method according to claim 1, further comprising means for performing a proximity effect correction operation using a pattern in a frame area provided outside each of the second, third, and fourth cells as a reference pattern. 6. The method according to claim 1, wherein the predetermined width of the first and second frame regions is longer than a scattering length of the backscattered electrons, which is a typical distance exerting the proximity effect. Proximity effect correction method. 7. The proximity effect correction method according to claim 3, wherein a width longer than a scattering length of backscattered electrons, which is a typical distance exerting the proximity effect, is adopted as the predetermined width of the frame region. . 8. The proximity device according to claim 4, wherein the predetermined width of the third frame region is a width longer than the scattering length of the backscattered electrons, which is a typical distance exerting the proximity effect. Effect correction method. 9. For a cell having no array structure,
When the pattern arrangement in the cell has a two-dimensional periodicity, a proximity effect correction operation is performed after reconstructing the cell as a set of a plurality of array element cells. Item 6. The proximity effect correction method according to item 3 or 5. 10. A method of dividing an array element cell in a cell having an array structure into a plurality of sub-zones and correcting a proximity effect for a pattern in the array element cell for each sub-zone. The proximity effect correction method according to claim 3, wherein the method is added.