JP2000138159A - Mask pattern creation method and apparatus - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To enable easy creation of a rough mask pattern used for "IDEAL exposure technology". A method of creating a mask pattern used in multiple exposure, comprising creating target pattern data to be formed after exposure, performing a logical operation on predetermined fine line pattern data and the target pattern data, and The mask pattern surface is classified into a plurality of types of regions based on, and the regions are grouped by light transmittance, and it is determined whether a grouping pattern formed by the grouped regions satisfies a predetermined mask pattern design rule. And
The grouping pattern that does not satisfy the design rule is corrected, and after combining a plurality of grouping patterns, it is determined whether the pattern satisfies the design rule, and if the pattern does not satisfy the design rule, correction is performed. When a plurality of types are obtained, an image corresponding to each mask pattern data is calculated, and one of them is selected based on the image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a mask pattern, and more particularly, to a first exposure method represented by normal exposure such as projection exposure, and a second exposure method having a higher resolution than the first exposure method. The first exposure method is used in multiple exposure in which a plurality of types of patterns are overprinted using the second exposure method and a pattern having a minimum line width corresponding to the second exposure method (hereinafter, referred to as a target pattern) is formed. The present invention relates to a method and an apparatus for creating a mask pattern (hereinafter, referred to as a rough pattern) to be used in the method. The above multiple exposure includes, for example, a semiconductor chip such as an IC or LSI, a display element such as a liquid crystal panel, a detection element such as a magnetic head, and a CC.
It is used for manufacturing various devices such as an image sensor such as D.

[0002]

2. Description of the Related Art At present, the mainstream of a projection exposure apparatus used for manufacturing devices such as ICs, LSIs and liquid crystal panels by using a photolithography technique uses an excimer laser as a light source. However, in a projection exposure apparatus using this excimer laser as a light source, a line width of 0.1
It is difficult to form a fine pattern of 5 μm or less under the current condition.

In order to increase the resolution, it is theoretically necessary to increase the NA (numerical aperture) of the projection optical system or to reduce the wavelength of the exposure light. It is not easy to reduce the wavelength of the exposure light. That is, the depth of focus of the projection optical system is inversely proportional to the square of NA and proportional to the wavelength λ.
Is increased, the depth of focus becomes smaller, focusing becomes difficult, and productivity decreases. Also, the transmittance of most glass materials is extremely low in the far ultraviolet region. At present, a glass material that can be used practically in a region of an exposure wavelength λ = 150 nm or less corresponding to a fine pattern having a line width of 0.15 μm or less by ordinary exposure has not been realized.

Therefore, by performing double exposure of two-beam interference exposure and normal exposure on the substrate to be exposed, and by giving a multi-level exposure amount distribution to the substrate to be exposed at that time, higher resolution is achieved. Is disclosed in Japanese Patent Application No. 9-304232, "Exposure method and exposure apparatus".
(Hereinafter referred to as the prior application). In the embodiment of the earlier application, the two-beam interference exposure is performed with a line width of 0.1 μmL & S.
Exposure is performed by so-called coherent illumination using a (line and space) phase shift mask.
Ordinary exposure (for example, exposure by partial coherent illumination) is performed using a mask in which a pattern corresponding to an actual element pattern of 1 μm and having a partially different light transmittance is formed. According to the method of the prior application, the exposure wavelength λ is 2
48 nm (KrF excimer laser), using a projection exposure apparatus in which the image side NA of the projection optical system is 0.6 for the normal exposure,
A pattern with a minimum line width of 0.10 μm can be formed.

As another method of exposing a fine pattern, a so-called probe exposure method of drawing and exposing a photosensitive member using a probe is known. As a probe, an STM using near-field light, a laser beam, an electron beam, a tunnel current, an AFM using an atomic force, or the like can be used. However, when the entire exposure area is probe-exposed, there is a problem that the throughput is low. Therefore, a portion of the target pattern that can be dealt with by normal exposure is exposed by the normal exposure with an amount of light exceeding the exposure threshold of the photoreceptor, and a portion with insufficient resolution does not reach the exposure threshold of the photoreceptor alone, but when both are combined, It is considered that the same multivalued exposure amount distribution as described above is provided by overprinting with normal exposure and probe exposure having an amount of light exceeding the exposure threshold of the photoreceptor (for example, Japanese Patent Application No. No. 10-137476 "Exposure method and exposure apparatus").

[0006]

However, according to the research of the present inventors, the above-mentioned multiple exposure (hereinafter referred to as "IDEA
In order to perform the “L exposure technique” more effectively, the mask pattern (rough pattern) used in the first exposure method represented by the normal exposure has a shape different from the thin line pattern (target pattern) actually desired to be formed. In addition, the rough pattern must meet the design rules of width and spacing, and different mask transmittances should be set for each region. As a result, a line pattern finer than the rough pattern (fine line pattern) It is necessary to satisfy both conditions that a desired fine line pattern is obtained when overprinting, the design rule of the rough pattern is different for the mask transmittance, it is necessary to satisfy each area,
It became clear that the creator of the data had to decide the final rough pattern shape and transmittance setting in consideration of both conditions.

One of the places where the fine line pattern is used is M
Although the formation of the gate of an OS transistor is conceivable, today, integrated circuits form circuits by integrating hundreds of thousands to millions of transistors, and data creators use hundreds of thousands to millions of It is very difficult to determine the pattern shape and transmittance satisfying the above conditions for all of the gates.

[0008] Another problem is that the "ideal exposure technique" uses a Levenson mask because a fine line pattern is formed only in an area where the Levenson mask data exists. Line width and spacing). However, in a semiconductor process that is created using a number of exposure processes, there is no design method for optimally arranging data corresponding to each process in order to maximize the integration density and device performance. Was not established.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to facilitate creation of a mask pattern (rough pattern) used in the "IDEAL exposure technique".

[0010]

In order to achieve the above-mentioned object, a mask pattern forming method according to the present invention comprises a step of forming data of a target pattern to be formed after exposure; a step of forming predetermined fine line pattern data and the target pattern data; Performing a logical operation of the following; a step of classifying the mask pattern surface into a plurality of types of regions based on the result of the logical operation; and setting of one or more light transmittances required or permitted according to the type of the region Then, a step of grouping regions in which the same light transmittance can be selected for each light transmittance, and determining whether a grouping pattern formed by the grouped regions satisfies a predetermined mask pattern design rule. Judge,
A first modification step of modifying a grouping pattern that does not satisfy the design rule to satisfy the design rule;
Synthesizing a grouping pattern formed for each of the light transmittances and corrected as necessary, and using the data of the synthesized pattern as mask pattern data, and further forming the synthesized pattern as the mask pattern data. A second correction step for determining whether or not the design rule is satisfied and a correction when the design rule is not satisfied; and in each correction step, a plurality of types of correction results are obtained for the same grouping pattern or composite pattern. Obtained, or a plurality of types of synthesis results are obtained in the synthesis step, and as a result, when a plurality of types of the mask pattern data are obtained, an image corresponding to each mask pattern data is calculated and obtained. Selecting one of the image data based on the image data.

Further, the mask pattern forming apparatus of the present invention stores a target pattern data to be formed after exposure and predetermined fine line pattern data, and performs a logical operation on the fine line pattern data and the target pattern data. Means for classifying the mask pattern surface into a plurality of types of regions based on the result of the logical operation; and setting one or more light transmittances required or permitted according to the type of the regions, Means for grouping regions in which the selectivity can be selected for each light transmittance; and determining whether or not a grouping pattern formed by the grouped regions satisfies a predetermined mask pattern design rule. A grouping pattern that does not satisfy the condition, the first correcting means for correcting the pattern so as to satisfy the design rule, and a grouping pattern formed for each light transmittance. Means for synthesizing the grouped pattern corrected as necessary, outputting the data of the synthesized pattern as mask pattern data, determining whether the synthesized pattern satisfies the design rule, and A second correction unit for performing a correction when the design rule is not satisfied, and a plurality of types of correction results for the same grouping pattern or composite pattern obtained by each of the correction units; When a plurality of types of mask pattern data are obtained as a result, an image corresponding to each mask pattern data is calculated, and one of the images is selected based on the obtained image data. And means for performing the following.

[0012]

Since most of the methods of the present invention are computer-executable, the data creator merely creates and inputs data (target pattern data) having the same shape as the pattern to be finally formed on the resist. Since the subsequent generation of the mask pattern data can be automatically performed by the computer according to the above procedure, the optimum mask pattern can be efficiently created even in the design of a large-scale semiconductor integrated circuit.

Further, in the present invention, since each pattern area divided for each light transmittance on the mask pattern is modified so as to satisfy the mask pattern design rule, the shape of the mask pattern and the light transmittance are changed. Exposure can be performed on the substrate with good reproducibility (faithful to the setting), and the target pattern can be formed on the substrate to be exposed with good reproducibility.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of the present invention, "I
A first step of creating fine line pattern data (Nor) corresponding to a fine line pattern to be formed after exposure, and a logical operation of Levenson pattern data (LEV) and Nor And a third step of grouping the data generated in the second step according to the set value of the transmittance of the mask; and designing the grouped data as a rough mask pattern. A fourth step of determining whether the rule is satisfied, a fifth step of correcting the grouped data according to the fourth determination result, and a grouping after the fourth and fifth steps. A sixth step of reproducing a pattern using the data obtained and setting a mask transmittance in each area of the grouped data; and Nor after the sixth step. A seventh step of performing a logical operation to determine whether or not a desired fine line pattern can be formed; and, based on the seventh determination result, correcting the setting of the pattern and transmittance of the data reproduced in the sixth step. Steps, an iterative operation step of repeating the fourth to seventh steps to find a solution that satisfies both the conditions for the design rule of the rough mask pattern and the setting of the mask transmittance, and when a plurality of solutions are obtained, An eighth step of calculating an image corresponding to each rough mask pattern and selecting one of the images based on the obtained image data.

In the above method, the second step includes:
For example, a step of performing an AND operation of LEV and Nor to generate first operation data, and converting the first operation data to LE
V, generating second operation data, removing the first operation data from Nor, generating third operation data, and calculating O of the first, second, and third data.
Performing the R operation and then performing the inversion operation to generate fourth operation data. Further, as a pattern correction method for satisfying the design rule of the rough mask pattern, there is a method of reducing or enlarging data, or a method of moving one side of data at a location where the rule is violated.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 is a flowchart showing a rough pattern data generating method according to an embodiment of the present invention, and FIG. 2 is a flowchart showing the generating method more specifically. Here, as shown in FIG. 3, a line width (light transmitting portion) is used as a fine line pattern.
And the interval (light shielding portion) are both L (L & S = L, pitch 2)
L, L is a fine periodic pattern (Levenson pattern) LEV of, for example, 0.10 μm), and a rough pattern Rou for forming a target pattern (a pattern to be finally formed) Nor by overlapping printing with the Levenson pattern. The method will be described. Levenson pattern LE
V is printed, for example, by the two-beam interference exposure with an amount of light that does not reach the exposure threshold of the photoresist, and the rough pattern Rou is printed using, for example, a normal projection exposure apparatus. The portion to be left as a thin line of the target pattern Nor is arranged at a pitch of 2L or an integer multiple thereof. The light-transmitting portion of the rough pattern Rou is a portion that transmits a light amount equal to or more than the exposure threshold of the photoresist independently of the presence or absence of the exposure by the Levenson pattern LEV, and a portion of the photoresist that is exposed only after overlapping with the exposure by the Levenson pattern LEV. This is set to a portion that transmits a light amount equal to or larger than the threshold value. The size (each light-transmitting part) and the interval (light-shielding part) of the rough pattern Rou are each n of L
(Where n is an integer of 2 or more).

Next, a data creation method according to this embodiment will be described with reference to FIGS. First, a pattern No. having the same shape as that to be finally formed on the photoresist
Create data of r. At this time, the data to be created as a thin line pattern (a pattern whose width or interval is L) is created so as to overlap the Levenson pattern LEV. It is assumed that the data of the Levenson pattern LEV has been input in advance.

Next, using the above two types of data, the following 4
One operation is performed to divide the data into four types of data as shown in FIG. Data A = LEV-D Data B = Nor-D Data C = Overall- (A OR BOR D) Data D = LEV AND Nor Here, based on the basic principle of “IDEAL exposure technology”, transmission through a portion without mask data is performed. Assuming that the transmittance is 0, the transmittance of the data area of the Levenson mask is 1, and the transmittance of the rough pattern mask is 1 and 2 depending on the data area, there are four types of transmittances 0, 1, 2, and 3 at the time of exposure by a combination of the two. Regions arise. At this time, by setting a threshold exposure amount between the areas 2 and 3 having high transmittance and the areas 0 and 1 having low transmittance, a desired amount of photoresist is formed on the photoresist corresponding to the area having a combination of 2 and 3 having high transmittance. A pattern is formed. The transmittances 0, 1, 2, and 3 shown here are for convenience, have no physical meaning, and are used for simplifying the description.

Considering data A to D under the above setting, data B corresponds to an area where a pattern is to be finally formed on a resist although LEV does not exist.
Rough pattern mask data with a transmittance of 2 must exist. Next, since the area of the data C is a place where there is no LEV data and a pattern is not finally formed on the resist, rough pattern mask data having a transmittance of 0 or 1 must be present. The selection of 0 or 1 is made later so as to satisfy the design rule relating to the width of the rough mask pattern. Since the area of data D has LEV data and corresponds to an area where a pattern is to be formed on the resist, rough pattern mask data having a transmittance of 1 or 2 must exist. Which of 1 and 2 is selected will be selected later so as to satisfy the design rule regarding the width of the rough mask pattern.

Next, data E is generated by performing an OR operation on data B and data D (FIG. 5). This area includes all areas to which the mask transmittance 2 may be assigned. Similarly, an OR operation of data B and data C is performed to generate data F (FIG. 6). This area includes all areas to which a mask transmittance of 1 may be assigned.

Next, the data E and F are modified so as to satisfy the design rule relating to the width of the rough pattern mask. Here, the width or interval of the LEV data or 1 / １ ／ of the pitch
2 is the minimum reference unit L, the minimum design rule of the rough pattern mask is twice as large as 2L, and the minimum design unit is L.
At this time, the data E and the data F are respectively reduced by L / 2 and then expanded by L / 2. That is, each side of the pattern represented by data E and data F is moved by L / 2 toward the inside of each pattern, and each side of the remaining pattern is moved toward the outside of each pattern by L / 2. Move by two. By this processing, the pattern area having the width L in the data E and the data F is removed, and the width 2 is obtained.
New data E1 and F1 in which only the L or more regions are extracted are generated.

Next, it is checked whether or not each of the data E1 and F1 satisfies the rough pattern interval rule (2L or more). If not, one or both sides of the data at the problem location are checked. The data is corrected by moving by L to satisfy the interval rule. After that, by moving the side, the data is again reduced and enlarged so as to satisfy the width rule, and new data E2 and F2 are generated. A plurality of E2s and F2s may occur depending on how the side moves. 5 and 6 also show examples of correction data E3 and F3 different from E2 and F2.

E2 is a candidate for an area to which a mask transmittance 2 is assigned, and F2 is a candidate for an area to which a mask transmittance 1 is assigned. Therefore, the data No. is stored in the area (FIG. 7) where OR of E2 and F2 is obtained.
r must be included. (E2
Both the area of OR F2) and the data Nor are compared, and a combination of the data E2 and the data F2 that does not satisfy the above condition is excluded.

Next, an area where data E2 and data F2 are ANDed is extracted. This region is assigned as a region of transmittance 1 or 2 so that the region to which each transmittance is assigned satisfies the design rule of the rough pattern. Those that do not satisfy the design rules at this stage are excluded. Through the above procedure, the final shape of the rough pattern and the allocation of the transmittance for each region are determined.

E3 is substituted for E2, and F3 is substituted for F2.
Similarly, in the case of using No. 3, the final shape of the rough pattern and the allocation of the transmittance for each region are determined (FIGS. 8 and 9). FIG. 10 shows an example in which the data NOR is not partially included in the area where OR of E3 and F2 is obtained, and is excluded from the rough pattern candidates. Thereby, in this embodiment, three rough pattern candidates shown in FIGS. 7 to 9 are obtained.
At the stage of synthesizing E2 (or E3) and F2 (or F3), E2 (or E3) and F2 (or F3)
The shape of the resulting rough pattern differs depending on which part is adopted in 3). For example, if E2 and F2 are ORed with F2 priority, that is, the pattern E2
When the pattern F2 is superimposed on the above, the rough pattern candidate shown in FIG. Also, as shown in FIG. 9C, the pattern F is placed on the pattern E2.
If 3 is overlapped, FIG.
(D) or a rough pattern candidate shown at the right end of FIG. 11 is obtained. The obtained rough pattern or rough pattern candidate is displayed on a display as shown in FIG.

When a plurality of rough pattern candidates are obtained,
In this embodiment, an image corresponding to each rough pattern is calculated, and one optimal rough pattern is selected based on the obtained images. Hereinafter, calculation and selection of an image according to the present embodiment will be described with reference to FIGS. In the upper part of FIG. 12, three types of rough pattern candidates of this embodiment are shown as A, B, and C. FIG. 13 is a diagram showing a work flow for selecting an optimal arrangement from among these three types of rough pattern candidates. First, this flow will be described.

First, for each of the plurality of rough mask arrangement candidates A to C, the exposure amount distribution by the rough mask is calculated. In this case, data of an exposure apparatus (not shown) and its projection optical system are used. Next, similarly, the exposure distribution is calculated for fine exposure. Next, based on the exposure distribution obtained by these two calculations, a total exposure image obtained as a result of the multiple exposure is calculated for each candidate. Each of the items required as the shape of the target pattern to be obtained with respect to this total exposure image is input as a check item, and based on the check item, it is determined whether each candidate's total exposure image is superior or inferior. Extract. Specific examples of check items include line width uniformity of gate lines, short-circuit between gates, area of contact portions, and the like. Check items can be determined. Further, it is not always necessary to input check items numerically. That is, the tester, the designer, the operator, and the like can directly compare the displayed images without making any check item setting.

FIG. 12 is a diagram relating to a specific example relating to the selection of the optimum rough mask arrangement using the flow as shown in FIG. 13, and is an example in which the selection operation is performed on the three rough mask candidates obtained in this embodiment. The middle part of FIG. 12 shows an exposure amount distribution (rough exposure amount) by each rough mask. FIG.
FIG. 12 shows the result of first calculating the rough mask alone for each of the three rough mask arrangement candidates A, B, and C in the upper part of FIG.
The middle row shows the contour lines. The mask has three discrete steps,
It has patterns with transmittances of 0%, 50% and 100%, but the exposure amount distribution is continuous. The fine line has a line width of 0.15 μm, and the projection optical system has a wavelength of 248.
nm, NA 0.6. Next, the exposure amount distribution (not shown) by the common periodic fine exposure was calculated, and the exposure amount was appropriately added to obtain a total exposure image in the lower part of FIG.

All three have shapes close to the target pattern to be obtained, indicating that the design algorithm for selecting candidates was correct. In addition, comparing the details of each shape, it can be seen that they have different parts. The final rough mask arrangement is selected based on this difference.

In the present embodiment, these total exposure images are displayed on the screen shown in FIG. 11 by switching to the rough pattern candidates or together with the reduced screen of the rough pattern candidates, and by the tester, based on this total exposure image. Decided which candidate to choose. As check items, emphasis was placed on line width uniformity of the gate line portion and gate line interval. As a result, it was concluded that B was optimal, and B was selected. The reason for this is that A becomes narrower in the portion where the gate line interval is close to the upper and lower contact portions, and there is a possibility that the pattern is connected and the wiring is short-circuited. It was mentioned that it has been done.

As described above, according to the present invention, when a plurality of mask arrangement candidates are obtained, by calculating the optical image obtained by the exposure apparatus, it is determined whether the candidates are superior or inferior or not. This is to select the most suitable candidate.

In this embodiment, the total exposure image is displayed on the screen and the tester makes a decision. However, the decision can be made automatically by internal calculation using the input check items. In this case, The total exposure image need not be displayed on the screen. In addition, the check items may be input in advance, and then the image may be calculated. The order of the flow illustrated in FIG. 13 may be appropriately changed. In the present embodiment, the selection operation is performed by using an optical image. However, information on the development process, for example, the sensitivity characteristics of the resist may be appropriately added, and these are also within the scope of the present invention.

According to the present embodiment, the data creator only has to create data (target pattern data) having the same shape as the pattern to be finally formed on the resist, and then to create the rough pattern mask data. Can be automatically generated by the computer according to the above-described procedure. Even when a plurality of rough pattern mask data candidates are generated, the exposure state of each candidate automatically calculated and displayed on the screen is visually checked with a mouse or the like. In this case, one of the rough patterns may be selected by giving an instruction using the input device described above, so that an optimum rough pattern can be generated at high speed even in the design of a large-scale semiconductor integrated circuit.

In recent years, in designing a large-scale logic circuit, a circuit designer often designs a circuit by logic description without being conscious of an actual layout pattern. In this case, after a procedure of generating a physical layout pattern formed on a resist based on the logical description data from the logical description, a procedure of automatically generating rough pattern mask data for the "IDEAL exposure technique" of the present embodiment. The circuit designer can design a semiconductor integrated circuit using a fine pattern by the "IDEAL exposure technique" in the same manner as before only by adding.

When a mask is created using the calculation results of the above-described embodiments, for example, a layer that can be handled on a CAD (Computer Aided Design) tool is assigned to each piece of data having a different mask transmittance. It can be mask creation data. Alternatively, on the same layer, a branch number called a data type may be different for each transmittance to be used as mask creation data.

In the above-described embodiment, the Levenson pattern has been described with a two-beam interference exposure as a fine line pattern. However, the fine line pattern may be a near-field light, a laser beam, an electron beam, or an STM. Exposure may be performed by probe drawing using an AFM or the like. In this case, in the probe drawing, it is sufficient to draw only a portion of the Levenson pattern that overlaps with the transmittance 1 of the rough pattern with the light amount corresponding to the transmittance 1, and the writing time can be greatly reduced. In addition, the fine line pattern is not limited to a periodic pattern such as a Levenson pattern, and a pattern in which fine periodic patterns such as a checkered pattern and a Levenson pattern are double-exposed to be orthogonal to each other can be used. Further, a pattern in which line patterns are not arranged at an equal pitch can be used.

Embodiment of Device Production Method Next, an embodiment of a device production method using the above-described exposure apparatus or exposure method will be described. FIG. 14 shows a micro device (a semiconductor chip such as an IC or an LSI, a liquid crystal panel,
2 shows a flow of manufacturing a CCD, a thin-film magnetic head, a micromachine, and the like. In step 1 (circuit design), a device pattern is designed. Step 2 is a process for making a mask on the basis of the designed pattern. on the other hand,
In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon or glass. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 15 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 1
In 5 (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses a conventional exposure apparatus using the above-described rough mask, and a second exposure apparatus for exposing a fine pattern.
The circuit pattern of the mask is printed and exposed on the wafer by the light beam interference exposure apparatus or the probe exposure apparatus. Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the production method of this embodiment, it is possible to produce a highly integrated device, which was conventionally difficult to produce, at low cost.

[0040]

As described above, according to the present invention, the data creator only needs to create and input data (target pattern data) having the same shape as the pattern to be finally formed on the resist. Since the mask pattern data can be automatically generated by the computer according to the above procedure, the optimum mask pattern can be efficiently created even in the design of a large-scale semiconductor integrated circuit.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a rough pattern data creation method according to an embodiment of the present invention.

FIG. 2 is a flowchart more specifically showing the creation method of FIG. 1;

FIG. 3 is an explanatory diagram showing a relationship between a Levenson pattern and a target pattern.

FIG. 4 is an explanatory diagram showing four types of weight regions obtained by a logical operation of Levenson pattern data and target pattern data.

FIG. 5 is an explanatory diagram showing a pattern obtained by grouping regions having the largest weight that can be selected, and how the pattern is modified so as to satisfy the design rule of a rough mask pattern.

FIG. 6 is an explanatory diagram showing a pattern obtained by grouping regions whose selectable weights are next to those of FIG. 5 and modifying the pattern so as to satisfy the design rule of a rough mask pattern.

FIG. 7 shows modified patterns E2 and F2 shown in FIGS. 5 and 6.
FIG. 9 is an explanatory diagram showing a state in which the shape of each weighted region is corrected, the transmittance is set according to the weight of each region, and a first rough mask pattern candidate is created.

FIG. 8 shows modified patterns E3 and F3 shown in FIGS. 5 and 6.
FIG. 11 is an explanatory diagram showing a state in which the shape of each weighted area is corrected, the transmittance is set according to the weight of each area, and a second rough mask pattern candidate is created.

FIG. 9 shows modified patterns E2 and F3 of FIGS. 5 and 6.
FIG. 11 is an explanatory diagram showing a state in which the shape of each weighted area is corrected, the transmittance is set according to the weight of each area, and a third rough mask pattern candidate is created.

FIG. 10 shows modified patterns E3 and F shown in FIGS. 5 and 6.
As a result of modifying the shape of each weight area by combining
FIG. 9 is an explanatory diagram illustrating a pattern that has become inappropriate as a rough mask pattern candidate.

FIG. 11 is an explanatory diagram showing a state where the rough mask pattern candidates of FIGS. 7 to 9 are displayed on a display.

FIG. 12 is a diagram of a rough exposure image and a total exposure image corresponding to each of the rough mask pattern candidates in FIGS. 7 to 9;

FIG. 13 is a flowchart illustrating an operation of selecting an optimum arrangement from a plurality of rough pattern candidates.

FIG. 14 is a diagram showing a flow of manufacturing a micro device.

FIG. 15 is a diagram showing a detailed flow of the wafer process in FIG. 14;

[Explanation of symbols]

LEV: Levenson pattern, Nor: target pattern,
Rou: Rough pattern.

Claims (12)

[Claims] 1. A target pattern having a minimum line width corresponding to the line width of the fine line pattern is formed by overprinting a fine line pattern and a mask pattern having a minimum line width larger than the line width of the fine line pattern. A method of creating a mask pattern used in multiple exposure for forming a target pattern data to be formed after exposure, and performing a logical operation on predetermined fine line pattern data and the target pattern data. Classifying the mask pattern surface into a plurality of types of regions based on the result of the logical operation; setting one or more light transmittances required or permitted according to the types of the regions; A step of grouping selectable regions for each light transmittance; and a step of synthesizing a grouping pattern formed for each light transmittance. The data of the synthesized pattern is used as mask pattern data, and further, it is determined whether or not a grouped pattern formed by the grouped areas satisfies a predetermined mask pattern design rule, and the design rule is determined. A first correction step of correcting the grouping pattern that does not satisfy the design rule to satisfy the design rule; and determining whether or not the synthesized pattern satisfies the design rule after synthesizing the plurality of grouping patterns. And a second correction step of performing a correction when the design rule is not satisfied; and that in each of the correction steps, a plurality of types of correction results are obtained for the same grouping pattern or composite pattern; , A plurality of types of synthesis results are obtained, and as a result, If obtained, the image corresponding to each of the mask pattern data is calculated, based on the obtained image data mask pattern forming method characterized by comprising the step of selecting one of them. 2. The method according to claim 1, wherein a line width of the fine line pattern is L.
The target pattern has a line width and an interval that is an integer multiple of 1 or more of L, the mask pattern has a line width and an interval that is an integer multiple of 2 or more of L, and each of the correction steps includes:
First, each side of the grouping pattern or the composite pattern is moved by L / 2 toward the inside of the light transmission pattern, and then each side of the light transmission pattern remaining after the movement is moved by L / 2 toward the outside. 2. The method according to claim 1, wherein only the pattern having a width of L is erased. 3. The correcting step includes, in a portion where the width of the gap between the light transmission patterns in the grouping pattern or the composite pattern in which the pattern having the width L is erased is L, one or both sides of the gap. The width of the gap is corrected to 2L or more by moving the gap toward the outside of the gap by L, and then the pattern having the width of L is erased from the corrected pattern, and the same correction process as in claim 5 is performed again. 3. The method according to claim 2, wherein 4. A target pattern having a minimum line width corresponding to the line width of the fine line pattern is formed by overprinting the fine line pattern and a mask pattern having a minimum line width larger than the line width of the fine line pattern. A mask pattern forming apparatus used in multiple exposure for storing data of a target pattern to be formed after exposure and predetermined fine line pattern data, and a logic of the fine line pattern data and the target pattern data. Means for performing an operation; means for classifying the mask pattern surface into a plurality of types of regions based on the result of the logical operation; and setting of one or more light transmittances required or permitted in accordance with the type of the region, and Means for grouping the regions in which the light transmittance can be selected for each light transmittance, and a grouping pattern formed by the grouped regions. First correction means for determining whether a pattern satisfies a predetermined mask pattern design rule, and correcting a grouping pattern not satisfying the design rule so as to satisfy the design rule; and Means for synthesizing the grouped pattern formed for each and correcting as necessary, outputting the data of the synthesized pattern as mask pattern data, and determining whether the synthesized pattern satisfies the design rule. A second correction unit for performing a determination and a correction when the design rule is not satisfied; and a plurality of types of correction results for the same grouping pattern or composite pattern are obtained in each of the correction units; When a plurality of types of synthesis results are obtained by the means, and as a result, a plurality of types of the mask pattern data are obtained, Calculating the image corresponding to the respective mask pattern data, the mask pattern creating apparatus characterized by comprising a means for selecting one of them based on the obtained image data. 5. The apparatus according to claim 4, further comprising means for displaying the obtained mask pattern data.
The mask pattern creating apparatus described in the above. 6. The line width of the fine line pattern is L,
The target pattern has a line width and an interval that is an integer multiple of 1 or more of L, and the mask pattern has a line width and an interval that is an integer multiple of 2 or more of L.
First, each side of the grouping pattern or the composite pattern is moved by L / 2 toward the inside of the light transmission pattern, and then each side of the light transmission pattern remaining after the movement is moved by L / 2 toward the outside. 6. The apparatus according to claim 4, wherein only the pattern having the width L is erased. 7. In a portion where a width of a gap between light transmitting patterns in a grouping pattern or a composite pattern in which a pattern having a width L is erased is L, one or both sides of the gap are corrected. 7. A pattern having a width of L for the corrected pattern by moving the gap toward the outside of the gap by L to correct the width of the gap to 2L or more.
7. The mask pattern creating apparatus according to claim 6, wherein the mask pattern is erased in the same manner as in the above. 8. A program, wherein the method according to claim 1 is described in a language executable by a computer. 9. A recording medium on which the program according to claim 8 is recorded. 10. A mask, wherein a mask pattern formed by using the method according to claim 1 or the apparatus according to claim 4 is formed. 11. A predetermined fine line pattern and a mask pattern produced by the method according to claim 1 or the apparatus according to claim 4 corresponding to the fine line pattern. And overprinting on the substrate to be exposed by different exposure methods to give a multilevel exposure distribution on the substrate to be exposed, and setting an exposure threshold at an appropriate position of the multilevel exposure. Forming a target pattern having a minimum line width corresponding to the line width of the fine line pattern. 12. A device manufactured by using the exposure method according to claim 11.