JP4068290B2 - Mask pattern correction method and correction apparatus - Google Patents

Description

マスク欠陥検査の限界寸法が１００ｎｍであり、▲１▼では隣接エッジ２２が補正対象となっているため、それが補正されることも考慮した上で最大補正量を決める必要がある。従って、（１６０−１００）／２＝３０ｎｍが最大補正量となる（Ｓ４）。▲２▼では、隣接エッジ２２が補正対象外でありそれは補正されないため、１６０−１００＝６０ｎｍが最大補正量となる。▲３▼▲４▼でも同様に求めると、それぞれ（５００−１００）／２＝２００ｎｍ，５００−１００＝４００ｎｍが最大補正量となる。全てのエッジに対して最大補正量が決まったら、この情報に基づいて設計パターンの各エッジを移動させる（Ｓ５）。そして、補正された設計パターンデータを基にマスクにパターンを形成することになる。。
【００３２】
このように本実施形態では、補正（エッジの移動工程）を行う前に各エッジ毎に最大補正量を決めた後、それぞれの最大補正量よりエッジ移動量が小さくなるように補正量を決める。こうすれば、図１（ａ）に示すような密集パターンでは▲１▼▲２▼のように、マスク欠陥検査限界の１００ｎｍ以下のエッジ間間隔を作らず、かつできる限り大きい最大補正量を設定することが可能となる。一方、図１（ｂ）に示すような孤立パターンでは▲３▼▲４▼のように、密集パターンに比べて大きい最大補正量を設定することが可能となる。この結果、マスク欠陥検査に影響を与えず、かつ補正精度を可能な限り劣化させることなく設計パターンの補正を行うことが可能となった。
【００３３】
（第２の実施形態）
第２の実施形態として、パターンのねじれを回避できる最大補正量の設定方法を説明する。
【００３４】
図３（ａ）のパターンの太線で示したエッジを補正する場合を考える。図中の３１，３２はパターン、３３は注目エッジ、３４は仕上がり形状を示している。太線で示した２つの注目エッジ３３（Ａ，Ｂ）に対して仕上り形状３４は外側にあるため、エッジＡ，Ｂは共にパターンに対して内側に補正されることが望ましい。このようなパターンを従来法で補正すると、仮に最大補正量が８０ｎｍ以上に設定されている場合には、図３（ｂ）に示すようにエッジＡ，Ｂが互いに内側に補正された結果、エッジＡとエッジＢの位置関係が入れ替わってしまい、パターンのねじれが発生する恐れがあった。このようになると、正しいシミュレーションを行うことができないため、正しい補正値を得ることができない。
【００３５】
本実施形態においては、補正前に補正対象エッジと隣接するエッジとの間隔を算出することができるので、ねじれパターンを発生しないように一方向に対する補正最大量を決定することができる。
【００３６】
図３（ａ）のパターンを用いて本実施形態による補正方法を説明する。まず、図３（ａ）のエッジＡを補正対象エッジであるとしたとき、補正を行う前にD.R.C.機能を用いてエッジＡとエッジＢとの間隔を算出する。ここで、マスク欠陥検査限界寸法が１００ｎｍであり、エッジＡとエッジＢとの間隔は１６０ｎｍであり、かつエッジＢは補正対象エッジであることも判断できるので、第１の実施形態で示した場合分けを行うと、エッジＡの一方向に対する最大補正量は（１００−１６０）／２＝−３０ｎｍと−方向に対する最大補正量を決定することができる。エッジＢに対しても同様に、−方向に対する最大補正量として−３０ｎｍを決定することができる。これにより、エッジ補正に伴うねじれパターンの発生を防止することができる。
【００３７】
そして、第１の実施形態に示した方法で＋方向の最大補正量を規定し、本実施形態に示した方法で−方向の最大補正量を規定することにより、マスク欠陥検査の限界寸法以下のパターンを作らず、かつねじれパターンも作らずに、かつ補正精度の劣化も可能な限り小さく抑えながら補正できることになる。
【００３８】
（第３の実施形態）
図４は、本発明の第３の実施形態に係わるマスクパターン補正装置の基本構成を示すブロック図である。なお、本装置は、例えば磁気ディスク等の記録媒体に記録されたプログラムを読み込み、このプログラムによって動作が制御されるコンピュータによって実現される。
【００３９】
図中の４１はマスクパターンの設計データ（設計パターン）とマスク上で許容される最短スペース幅Ｓlim 及び最短ライン幅Ｌlim を入力するためのパターン入力部、４２は注目するエッジが補正対象か否かを判定する第１の判定部、４３は注目エッジと隣接するエッジとの最短スペース距離Ｓmin 及び最短ライン距離Ｌmin のうち少なくとも一方を算出する算出部、４４は注目エッジに隣接するエッジが補正対象か否かを判定する第２の判定部、４５は判定結果に基づいてエッジ毎に最大移動可能量を演算する演算部、４６は演算結果を出力する出力部を示している。
【００４０】
図５に、上記補正装置を用いたマスクパターン補正方法の処理フローを示す。まず、補正対象エッジを含む設計パターンを入力する（Ｓ１）。このとき、マスク上で許容される最短スペース幅Ｓlim と最短ラインＬlim をそれぞれ入力する（Ｓ２）。
【００４１】
次いで、注目するエッジが補正対象であるか否かを判定する（Ｓ３）。補正対象外である場合は、エッジ最大移動量ｘ＝０を設定する（Ｓ４）。補正対象である場合は、マスクパターン補正装置に組込まれたD.R.C.機能を用いて、補正対象エッジと隣接するエッジとの間隔を算出する（Ｓ５）。具体的には、エッジ間最短距離Ｓmim ，Ｌmin を算出し、更に最短距離とエッジとの成す角α，βを算出する。
【００４２】
次いで、注目エッジに隣接する隣接エッジが補正対象であるか否かを判定し（Ｓ６）、補正対象エッジか補正対象外エッジかに応じて場合分けを行う（Ｓ７，Ｓ８）。そして、決められたマスク欠陥検査の限界寸法値を用いて、場合分けに応じて演算処理を行い、各エッジに＋方向の最大補正量と−方向の最大補正量とをそれぞれ設定する（Ｓ９）。この設定が終了した後、この最大補正量の条件を満たすように補正を行い（Ｓ１０）、その結果である補正パターンを出力する（Ｓ１１）。
【００４３】
このような手順で補正を行うことにより、マスク欠陥検査限界寸法以下のパターンとねじれパターンを作らず、補正精度の劣化をできるだけ小さく抑えて補正を行うことができた。
【００４４】
（第４の実施形態）
第４の実施形態として、注目するエッジと隣接エッジとの最短距離を示す直線がそれぞれのエッジに対して９０度又は２７０度でない場合の例を説明する。図６は、本発明の第４の実施形態に係わるマスクパターン補正方法を説明するための図であり、６１，６２はパターン、７１は注目エッジ、７２は隣接エッジを示している。
【００４５】
図６に示すように、注目エッジ７１と隣接するエッジ７２との最短距離をＳmin とし、その最短距離を結ぶ直線と注目エッジ７１に対する垂線との成す角をα、隣接エッジ７２に対する垂線との成す角をβとし、マスク上許容される最小スペース幅をＳlim とし、この条件でのエッジ最大移動可能量をｘとする。このとき、以下の式が成り立つ。
【００４６】
Smin -Slim =x/cosα+x/cosβ
∴ｘ＝(Smin-Slim)/(1/cosα+1/cosβ)
この式は隣接エッジも補正対象の場合であり、隣接エッジが補正対象外の場合には、
Smin -Slim ＝ｘ／cos α
∴ｘ＝（Smin-Slim）／（1/cosα）
となる。この式により最大移動可能量ｘが算出できる。このｘの値に従って補正を行うことにより、マスク上許容される最短スペース幅をほぼ確保することができ、マスクプロセス負荷を低減させることができる。また、本実施形態ではスペースに対するエッジ最大移動可能量を算出する例を示したが、これはラインに対しても同様に適用することができる。
【００４７】
なお、本発明は上述した各実施形態に限定されるものではない。例えば、各実施形態で説明した補正方法に加え、補正精度の更なる向上をはかるために、マスクの最大補正量を補正計算を行う度に算出するようにしてもよい。言い換えると、マスクパターンの補正は通常、補正値を収束させるために繰り返し計算を行っているため、その繰り返しの度に実施形態で示したように最大補正量を算出することも可能である。既に補正された値を考慮しながら最大補正量を決定することによって、より精度良く補正を行うことが可能となる。
【００４８】
上記のように補正値を繰り返し計算により決定する場合、隣接エッジが補正されるエッジか否かを考慮せずに最大移動可能量を決定してもよい。これは、決定した最大移動可能量を加えた状態で、該エッジと隣接するエッジとの間隔に基づいて最大移動可能量を再決定することになり、隣接エッジが補正されるエッジか否かを考慮しなくても精度良い補正が可能となるためである。
【００４９】
また本発明は、コンピュータに実行させることのできるプログラムとして、例えば磁気ディスク（フロッピーディスク，ハードディスク等）、光ディスク（ＣＤ−ＲＯＭ，ＤＶＤ等）、半導体メモリなどの記録媒体に書き込んで各種装置に適用したり、通信媒体により伝送して各種装置に適用することも可能である。本装置を実現するコンピュータは、記録媒体に記録されたプログラムを読み込み、このプログラムによって動作が制御されることにより、上述した処理を実行することになる。
【００５０】
その他、本発明の要旨を逸脱しない範囲で、種々変形して実施することができる。
【００５１】
【発明の効果】
以上詳述したように本発明によれば、設計パターンのエッジを移動させる工程の前に、設計パターンの各エッジ毎にその周辺環境（注目エッジと隣接するエッジとの間隔、及び該隣接エッジが補正されるエッジか否か等）に基づいて該エッジの最大移動可能量を決定することにより、マスク欠陥検査限界寸法以下のパターンとねじれパターンを作らず、補正精度の劣化をできるだけ小さく抑えて補正を行うことができる。
【図面の簡単な説明】
【図１】第１の実施形態に係わるマスクパターン補正方法を説明するための図。
【図２】第１の実施形態によるマスク補正方法の処理フローを示す図。
【図３】第２の実施形態に係わるマスクパターン補正方法を説明するための図。
【図４】第３の実施形態に係わるマスクパターン補正装置の基本構成を示すブロック図。
【図５】第３の実施形態におけるマスクパターン補正方法の処理フローを示す図。
【図６】第４の実施形態に係わるマスクパターン補正方法を説明するための図。
【符号の説明】
１１，２１，３１，３２，６１，６２…パターン
１２，２２，３３，７１，７２…エッジ
３４…仕上がり形状
４１…パターン入力部
４２…第１の判定部
４３…算出部
４４…第２の判定部
４５…演算部
４６…出力部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mask pattern correction method, a mask pattern correction apparatus for correcting design pattern data which is a base for forming a pattern on an exposure mask, and a recording medium storing a program for mask pattern correction. .
[0002]
[Prior art]
Recent progress in semiconductor manufacturing technology is very remarkable, and semiconductors with a minimum processing dimension of 0.2 μm have already been mass-produced. Such miniaturization is realized by dramatic progress in fine pattern formation techniques such as a mask process technique, an optical lithography technique, and an etching technique.
[0003]
When the pattern size is large enough, the planar shape of the LSI pattern to be formed on the wafer is directly drawn as a design pattern, a mask pattern that is faithful to the design pattern is created, and the mask pattern is transferred onto the wafer by the projection optical system. Then, by etching the base, a pattern almost as designed can be formed on the wafer. However, as pattern miniaturization progresses, it has become difficult to faithfully form a pattern in each process, and a problem has arisen that the final finished dimension does not match the design pattern.
[0004]
In order to solve these problems, taking into account conversion differences in each process, means for creating a mask pattern different from the design pattern so that the final finished dimension becomes equal to the design pattern dimension (hereinafter referred to as mask data processing). ) Has become very important.
[0005]
Mask data processing includes MDP processing for changing a pattern using a graphic operation processing and a design rule checker (DRC), and optical proximity effect correction (OPC) processing for correcting an optical proximity effect (OPE). However, with the recent miniaturization of patterns, a higher-accuracy model using an optical model from the OPC processing (rule-based OPC processing) that has been performed using the conventional MDP processing method is used as a basis. OPC processing is becoming mainstream. In model-based OPC processing, a finished prediction simulation is performed assuming that a given design pattern is a pattern to be formed on a wafer, and correction is performed so that the simulation result substantially matches the design pattern.
[0006]
As the correction amount in this case, an arbitrary value can be taken as long as there is no limitation. Therefore, the interval between an edge and an adjacent edge may be very small. If this interval is smaller than the resolution of the mask defect inspection, a pseudo defect is generated in the mask defect inspection, and the inspection must be performed with reduced inspection sensitivity. As a result, since the inspection sensitivity is low on the entire mask surface, there is a possibility that a defect that should originally be detected may be overlooked.
[0007]
In order to solve this problem, as proposed in Japanese Patent Laid-Open No. 11-174659, the corrected pattern is compared with the verification pattern in which each edge of the original pattern is resized by the maximum correction amount, and correction is performed. There is a method in which it is verified that the pattern is not corrected larger than the limited maximum correction amount, and if a correction amount larger than the maximum correction amount is included, the correction amount of that portion is changed.
[0008]
However, this type of method has the following problems (1) to (3).
[0009]
(1) If the maximum correction amount is limited so that the distance between corrected edges does not fall below a certain value, even for patterns that can be corrected further than the limited maximum correction amount, such as isolated patterns. Since the maximum correction amount is applied, the correction amount may not be achieved.
[0010]
(2) If pattern verification is performed after correcting without limiting the maximum correction amount and the correction amount is changed when the interval between edges is smaller than the limit, the correction accuracy itself deteriorates and the finished shape I cannot guarantee it.
[0011]
(3) When the edge is corrected to the inside of the pattern (corrected to make the pattern thinner), if the movement amount of the edge is defined only by the maximum correction amount, the pattern may be twisted in some cases .
[0012]
[Problems to be solved by the invention]
As described above, in the conventional mask pattern correction method, when the maximum correction amount for the edge is limited, the correction amount may not be achieved. Conversely, pattern verification is performed after correction without limiting the maximum correction amount. If this method is used to change the correction amount, the correction accuracy itself deteriorates and the finished shape cannot be guaranteed. Further, if the edge movement amount is defined only by the maximum correction amount, the pattern may be twisted.
[0013]
The present invention has been made in consideration of the above circumstances, and the object of the present invention is to suppress the deterioration of correction accuracy as much as possible while keeping the limit value of the mask defect inspection apparatus, and to prevent the twist pattern. It is an object of the present invention to provide a mask pattern correction method and correction apparatus capable of suppressing the occurrence, and a recording medium storing a mask pattern correction program.
[0014]
[Means for Solving the Problems]
(Constitution)
In order to solve the above problems, the present invention adopts the following configuration.
[0015]
That is, the present invention is a mask pattern correction method for correcting a design pattern as a base when forming a pattern on a mask so that the pattern formed on the mask is transferred onto the wafer as designed. Determining the maximum possible movement amount of each edge of the design pattern based on the surrounding environment, and moving the edges of the design pattern in accordance with the determined maximum movable amount. Features.
[0016]
Here, preferred embodiments of the present invention include the following.
[0017]
(1) As a step of determining the maximum movable amount, the maximum movable amount is determined based on the interval between the edge and the adjacent edge for each edge of the design pattern, and whether or not the adjacent edge is an edge to be corrected. decide.
[0019]
(2) In the step of determining the maximum movable amount, different values are determined depending on the moving direction.
[0020]
(3) In the process of determining the maximum movable amount, it must be determined according to the inspection limit dimension of the mask defect inspection apparatus.
[0021]
The present invention also provides a mask pattern correction method for correcting a design pattern as a base when forming a pattern on a mask so that the pattern formed on the mask is transferred onto the wafer as designed. A first step that defines the minimum space width Slim and the minimum line width Llim of the pattern allowed in step 2, a second step that determines whether or not the target edge is a correction target, and an edge adjacent to the target edge A third step of calculating at least one of the shortest space distance Smin and the shortest line distance Lmin, a fourth step of determining whether an edge adjacent to the target edge is a correction target, a second step and a second step And a fifth step of calculating a maximum movable amount for each edge based on the determination result in step 4.
[0022]
Here, in the third step, the angle α formed between the straight line indicating the shortest distance between the target edge and the adjacent edge and the perpendicular to the target edge, and the angle β formed between the adjacent edge and the straight line indicating the shortest distance are simultaneously calculated. When at least one of these angles is not 90 degrees or 270 degrees, it is desirable to calculate the maximum movable amount in consideration of the angles α and β in the calculation in the fifth step.
[0023]
The present invention also provides a mask pattern correction apparatus for correcting a design pattern as a base when forming a pattern on a mask so that the pattern formed on the mask is transferred onto the wafer as designed. The input unit for inputting the minimum space width Slim and the minimum line width Llim allowed in step 1, the first determination unit for determining whether or not the target edge is the correction target, and the shortest of the adjacent edge to the target edge The calculation results for calculating at least one of the space distance Smin and the shortest line distance Lmin, the second determination unit for determining whether or not the edge adjacent to the target edge is a correction target, and the determination results of the determination units A calculation unit that calculates a maximum movable amount for each edge based on the output and an output unit that outputs a calculation result are provided.
[0024]
The present invention also provides a program for correcting a design pattern that is a basis for forming a pattern on a mask so that the pattern formed on the mask is transferred onto the wafer as designed. In a computer-readable recording medium storing a program for controlling, the program focuses on a first procedure that defines a minimum space width Slim and a minimum line width Llim of a pattern allowed on the mask. A second procedure for determining whether or not the edge is a correction target; a third procedure for calculating at least one of the shortest space distance Smin and the shortest line distance Lmin between the edge of interest and the adjacent edge; and the edge of interest For each edge based on the determination result in the fourth procedure for determining whether the edge adjacent to the correction target is the correction target and the second and fourth procedures And controlling the computer to execute a fifth procedure for calculating the maximum movable amount.
[0025]
(Function)
According to the present invention, prior to the step of moving the edge of the design pattern, for each edge of the design pattern, the surrounding environment (the distance between the edge of interest and the adjacent edge, and whether the adjacent edge is an edge to be corrected) Etc.), the mask that does not create a pattern that is less than the mask defect inspection limit dimension, does not create a twist pattern, and degrades the correction accuracy as much as possible. Pattern correction can be performed. As a result, the finished pattern shape formed on the wafer can be formed faithfully to the design pattern.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described below with reference to the illustrated embodiments.
[0027]
(First embodiment)
FIGS. 1A and 1B are views for explaining a mask pattern correction method according to the first embodiment of the present invention. (A) is an example where the distance between adjacent patterns is short (dense pattern), (b) is an example where the distance between adjacent patterns is long (isolated pattern), 11 and 21 in the figure indicate patterns, and 12 and 22 indicate edges. ing.
[0028]
In FIGS. 1A and 1B, it is assumed that the critical dimension of mask inspection sensitivity is 100 nm (converted on the wafer), and the shortest edge interval of the design pattern defined in advance by the design rule is 160 nm. In the conventional mask pattern correction method, the following two correction methods are mainly used. The first method is a method of performing correction by limiting the maximum correction amount allocated to all edges to (160-100) / 2 = 30 nm. The second method performs correction without limiting the maximum correction amount, creates verification data from design data, compares and verifies the corrected data and verification data, and the interval between edges is mask defect inspection. This is a method of changing the correction amount so as to be equal to or greater than the limit value.
[0029]
However, as described in the section of the prior art, the first method is effective for the dense pattern shown in FIG. 1 (a), but effective for the isolated pattern shown in FIG. 1 (b). Not a way. This is because an isolated pattern does not have a pattern around it, so that the mask dimension does not exceed the inspection limit value even with a correction amount of 30 nm or more. In the second method, since the finished shape on the wafer is changed by changing the correction amount after correction, there is a possibility that the correction accuracy is deteriorated.
[0030]
The processing flow of the mask correction method according to the present embodiment is shown in FIG. Assume that the edge 12 indicated by the thick line in FIGS. 1A and 1B is corrected. First, after inputting a design pattern (S1), before performing correction, the distance from the thick line edge 12 to the adjacent edge 22 is calculated using DRC or the like (S2). At the same time as calculating the distance, it is determined whether the adjacent edge 22 is an edge to be corrected or an edge not to be corrected (S3). Whether an edge is to be corrected or not can be determined by looking at the layer number assigned to the edge. As a result, the thick line edges 12 in FIGS. 1A and 1B are classified into the following four cases.
[0031]

The critical dimension for mask defect inspection is 100 nm, and in (1), since the adjacent edge 22 is a correction target, it is necessary to determine the maximum correction amount in consideration of the correction. Accordingly, (160-100) / 2 = 30 nm is the maximum correction amount (S4). In (2), since the adjacent edge 22 is not subject to correction and is not corrected, 160-100 = 60 nm is the maximum correction amount. In the same way for (3) and (4), the maximum correction amounts are (500-100) / 2 = 200 nm and 500-100 = 400 nm, respectively. When the maximum correction amount is determined for all the edges, each edge of the design pattern is moved based on this information (S5). Then, a pattern is formed on the mask based on the corrected design pattern data. .
[0032]
As described above, in this embodiment, after the maximum correction amount is determined for each edge before the correction (edge moving step) is performed, the correction amount is determined so that the edge movement amount is smaller than each maximum correction amount. In this way, in the dense pattern as shown in FIG. 1 (a), as in (1) and (2), an interval between edges of 100 nm or less, which is the mask defect inspection limit, is not created, and the largest possible correction amount is set. It becomes possible to do. On the other hand, in the isolated pattern as shown in FIG. 1B, as shown in (3) and (4), it is possible to set a larger maximum correction amount than in the dense pattern. As a result, the design pattern can be corrected without affecting the mask defect inspection and without degrading the correction accuracy as much as possible.
[0033]
(Second Embodiment)
As a second embodiment, a method of setting a maximum correction amount that can avoid pattern twisting will be described.
[0034]
Consider a case where the edge indicated by the thick line in the pattern of FIG. In the figure, 31 and 32 are patterns, 33 is a target edge, and 34 is a finished shape. Since the finished shape 34 is on the outside with respect to the two target edges 33 (A, B) indicated by bold lines, it is desirable that both the edges A, B are corrected to the inside of the pattern. When such a pattern is corrected by the conventional method, if the maximum correction amount is set to 80 nm or more, the edges A and B are corrected inward as shown in FIG. The positional relationship between A and the edge B is switched, and there is a risk that the pattern is twisted. In this case, a correct simulation cannot be performed, and a correct correction value cannot be obtained.
[0035]
In this embodiment, since the interval between the correction target edge and the adjacent edge can be calculated before correction, the maximum correction amount in one direction can be determined so as not to generate a twist pattern.
[0036]
The correction method according to the present embodiment will be described using the pattern shown in FIG. First, assuming that the edge A in FIG. 3A is a correction target edge, the distance between the edge A and the edge B is calculated using the DRC function before correction. Here, the mask defect inspection limit dimension is 100 nm, the interval between the edge A and the edge B is 160 nm, and the edge B can also be determined to be a correction target edge. Therefore, the case shown in the first embodiment When dividing, the maximum correction amount for one direction of the edge A is (100−160) / 2 = −30 nm, and the maximum correction amount for the negative direction can be determined. Similarly, for edge B, −30 nm can be determined as the maximum correction amount for the −direction. Thereby, generation | occurrence | production of the twist pattern accompanying edge correction can be prevented.
[0037]
Then, the maximum correction amount in the + direction is specified by the method shown in the first embodiment, and the maximum correction amount in the-direction is specified by the method shown in the present embodiment, so that it is less than the critical dimension of the mask defect inspection. The correction can be performed without making a pattern, without forming a twist pattern, and suppressing deterioration in correction accuracy as much as possible.
[0038]
(Third embodiment)
FIG. 4 is a block diagram showing a basic configuration of a mask pattern correction apparatus according to the third embodiment of the present invention. The apparatus is realized by a computer that reads a program recorded on a recording medium such as a magnetic disk and whose operation is controlled by the program.
[0039]
In the figure, 41 is a pattern input unit for inputting mask pattern design data (design pattern) and the shortest space width Slim and shortest line width Llim allowed on the mask, and 42 is whether or not the target edge is a correction target. Is a first determination unit 43 for calculating at least one of the shortest space distance Smin and the shortest line distance Lmin between an edge of interest and an adjacent edge, and 44 is an edge adjacent to the edge of interest to be corrected A second determination unit that determines whether or not, 45 is a calculation unit that calculates the maximum movable amount for each edge based on the determination result, and 46 is an output unit that outputs the calculation result.
[0040]
FIG. 5 shows a processing flow of a mask pattern correction method using the correction device. First, a design pattern including a correction target edge is input (S1). At this time, the shortest space width Slim and the shortest line Llim allowed on the mask are input (S2).
[0041]
Next, it is determined whether or not the target edge is a correction target (S3). If it is not subject to correction, the maximum edge movement amount x = 0 is set (S4). If it is a correction target, the distance between the correction target edge and the adjacent edge is calculated using the DRC function incorporated in the mask pattern correction apparatus (S5). Specifically, the shortest distances Smim and Lmin between the edges are calculated, and the angles α and β formed by the shortest distances and the edges are calculated.
[0042]
Next, it is determined whether or not the adjacent edge adjacent to the target edge is a correction target (S6), and the case is classified according to whether the edge is a correction target edge or a non-correction target edge (S7, S8). Then, using the determined critical dimension value for mask defect inspection, arithmetic processing is performed according to the case, and the maximum correction amount in the + direction and the maximum correction amount in the-direction are set for each edge (S9). . After this setting is completed, correction is performed so as to satisfy the condition of the maximum correction amount (S10), and a correction pattern as a result is output (S11).
[0043]
By performing the correction according to such a procedure, it was possible to perform the correction while minimizing the deterioration of the correction accuracy as much as possible without creating a pattern and a twist pattern which are smaller than the mask defect inspection limit dimension.
[0044]
(Fourth embodiment)
As a fourth embodiment, an example will be described in which a straight line indicating the shortest distance between an edge of interest and an adjacent edge is not 90 degrees or 270 degrees with respect to each edge. FIG. 6 is a diagram for explaining a mask pattern correction method according to the fourth embodiment of the present invention, in which 61 and 62 are patterns, 71 is a target edge, and 72 is an adjacent edge.
[0045]
As shown in FIG. 6, the shortest distance between the target edge 71 and the adjacent edge 72 is Smin, the angle between the straight line connecting the shortest distance and the perpendicular to the target edge 71 is α, and the perpendicular to the adjacent edge 72 is formed. The angle is β, the minimum space width allowed on the mask is Slim, and the maximum edge movable amount under this condition is x. At this time, the following equation holds.
[0046]
Smin -Slim = x / cosα + x / cosβ
∴x = (Smin-Slim) / (1 / cosα + 1 / cosβ)
This formula is for cases where adjacent edges are also subject to correction.
Smin -Slim = x / cos α
∴x = (Smin-Slim) / (1 / cosα)
It becomes. The maximum movable amount x can be calculated from this equation. By performing correction according to the value of x, the shortest space width allowed on the mask can be almost ensured, and the mask process load can be reduced. In the present embodiment, the example of calculating the maximum edge movement amount with respect to the space has been shown, but this can be similarly applied to the line.
[0047]
In addition, this invention is not limited to each embodiment mentioned above. For example, in addition to the correction method described in each embodiment, the maximum correction amount of the mask may be calculated every time correction calculation is performed in order to further improve the correction accuracy. In other words, the correction of the mask pattern is normally performed repeatedly to converge the correction value, so that the maximum correction amount can be calculated as shown in the embodiment each time the correction is repeated. By determining the maximum correction amount in consideration of the already corrected value, correction can be performed with higher accuracy.
[0048]
When the correction value is determined by repeated calculation as described above, the maximum movable amount may be determined without considering whether the adjacent edge is an edge to be corrected. In this state, with the determined maximum movable amount added, the maximum movable amount is re-determined based on the interval between the edge and the adjacent edge, and whether or not the adjacent edge is an edge to be corrected is determined. This is because accurate correction can be performed without consideration.
[0049]
Further, the present invention is applied to various apparatuses as programs that can be executed by a computer, for example, written on a recording medium such as a magnetic disk (floppy disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, etc. It can also be applied to various devices by being transmitted through a communication medium. A computer that implements this apparatus reads the program recorded on the recording medium, and controls the operation by this program, thereby executing the above-described processing.
[0050]
In addition, various modifications can be made without departing from the scope of the present invention.
[0051]
【The invention's effect】
As described above in detail, according to the present invention, before the step of moving the edge of the design pattern, the surrounding environment (the distance between the target edge and the adjacent edge, and the adjacent edge is determined for each edge of the design pattern. By determining the maximum movable amount of the edge based on whether or not it is the edge to be corrected, etc., it is possible to correct without minimizing the deterioration of the correction accuracy as much as possible without creating patterns and twist patterns that are less than the mask defect inspection limit dimension. It can be performed.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a mask pattern correction method according to a first embodiment.
FIG. 2 is a diagram showing a processing flow of a mask correction method according to the first embodiment.
FIG. 3 is a view for explaining a mask pattern correction method according to a second embodiment.
FIG. 4 is a block diagram showing a basic configuration of a mask pattern correction apparatus according to a third embodiment.
FIG. 5 is a diagram showing a processing flow of a mask pattern correction method according to a third embodiment.
FIG. 6 is a view for explaining a mask pattern correction method according to a fourth embodiment.
[Explanation of symbols]
11, 21, 31, 32, 61, 62 ... patterns 12, 22, 33, 71, 72 ... edge 34 ... finished shape 41 ... pattern input unit 42 ... first determination unit 43 ... calculation unit 44 ... second determination Unit 45 ... Calculating unit 46 ... Output unit

Claims (8)

A mask pattern correction method for correcting a design pattern as a base when forming a pattern on a mask so that the pattern formed on the mask is transferred onto the wafer as designed.
For each edge of the design pattern, determining a maximum movable amount of the edge based on the surrounding environment, and moving the edge of the design pattern according to the determined maximum movable amount A mask pattern correction method characterized by the above.   In the step of determining the maximum movable amount, the maximum movable amount is determined based on an interval between each edge of the design pattern and an adjacent edge and whether the adjacent edge is an edge to be corrected. The mask pattern correcting method according to claim 1, wherein: 3. The mask pattern correction method according to claim 1, wherein the step of determining the maximum movable amount sets a different value depending on a moving direction. 4. 3. The mask pattern correction method according to claim 1, wherein the step of determining the maximum movable amount performs the determination according to an inspection limit dimension of a mask defect inspection apparatus. A mask pattern correction method for correcting a design pattern as a base when forming a pattern on a mask so that the pattern formed on the mask is transferred onto the wafer as designed.
A first step of defining a minimum space width Slim and a minimum line width Llim of a pattern allowed on the mask; a second step of determining whether or not the target edge is a correction target; and the target edge A third step of calculating at least one of the shortest space distance Smin and the shortest line distance Lmin with an adjacent edge, a fourth step of determining whether an edge adjacent to the target edge is a correction target, And a fifth step of calculating a maximum movable amount for each edge based on the determination results in the second and fourth steps. In the third step, the angle α formed between the straight line indicating the shortest distance between the target edge and the adjacent edge and the perpendicular to the target edge, and the angle β formed between the adjacent edge and the straight line indicating the shortest distance are simultaneously calculated. If at least one of the angles is not 90 degrees or 270 degrees, in the operation in the fifth step, alpha, according to claim 5, wherein computing the maximum movable amount angle in consideration of the β Mask pattern correction method. A mask pattern correction apparatus that corrects a design pattern as a base when forming a pattern on a mask so that the pattern formed on the mask is transferred onto the wafer according to a design value,
An input unit for inputting a minimum space width Slim and a minimum line width Llim of a pattern allowed on the mask, a first determination unit for determining whether or not the target edge is a correction target, and adjacent to the target edge A calculation unit that calculates at least one of the shortest space distance Smin and the shortest line distance Lmin with the edge, a second determination unit that determines whether an edge adjacent to the target edge is a correction target, and each determination unit A mask pattern correction apparatus comprising: a calculation unit that calculates a maximum movable amount for each edge based on the determination result; and an output unit that outputs the calculation result. A program for correcting by a computer a design pattern that is the basis for forming a pattern on a mask so that the pattern formed on the mask is transferred onto the wafer as designed.
A first procedure for defining a minimum space width Slim and a minimum line width Llim of a pattern allowed on the mask; a second procedure for determining whether or not the target edge is a correction target; A third procedure for calculating at least one of the shortest space distance Smin and the shortest line distance Lmin with an adjacent edge, a fourth procedure for determining whether an edge adjacent to the target edge is a correction target, A computer-readable recording medium storing a program for controlling the computer to execute a fifth procedure for calculating a maximum movable amount for each edge based on the determination results in the second and fourth procedures .

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