JP3229904B2 - Step and repeat type charged particle beam writing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-and-repeat type charged particle beam drawing method for drawing a predetermined pattern on a material using an electron beam or an ion beam.

[0002]

2. Description of the Related Art For example, in electron beam writing of the step-and-repeat method, writing data is divided into a range (field) where writing is performed only by deflection of an electron beam, and a material is intermittently moved for each field. When the material is stopped, the pattern included in each field is drawn.

[0003]

FIG. 1 is a schematic diagram of a dashed line.
Two fields F₁, F₂In the field
FIG. Among them, the pattern P₁
Is the entire field F₁And the pattern P
₅Is all in field F₂Is included in.
Also, the pattern P₂, P₃, P₄Means both fields
Are arranged to straddle. Drawing such a pattern
First, a pattern that straddles both fields
P₂, P₃, P₄Data of each field
P_{twenty one}, P _{twenty two}, P₃₁, P₃₂, P₄₁, P₄₂Divided into
You. And field F₁Draw pattern included in
When you do, field F₁Center and electron beam light
The material is moved so that the axis coincides. afterwards,
Based on the pattern data, the pattern P₁, P_{twenty one},
P₃₁, P₄₁, Are drawn. Then, put the material in the field
Field F₂Center and optical axis
To match. Then, based on the pattern data,
P_{twenty two}, P₃₂, P₄₂, P₅Is drawn.

In such a drawing method, in order to perform drawing for each field, a pattern straddling an adjacent field is divided, and drawing is performed in a field to which each belongs. However, a step of mechanically moving the material (stage) is inserted between each drawing of the divided pattern. The mechanical movement of the material involves a non-negligible movement error, and as a result, as shown in FIG. 2, a pattern shift occurs in the field boundary at the time of drawing the divided pattern. This shift appears as an extreme step at the edge of the pattern, or the connection of the divided pattern cannot be performed due to the content of the movement error, and the pattern is missed at the field boundary. What is to be a pattern may be substantially two patterns. These steps are not preferable in terms of the performance of a device manufactured based on the drawing. In particular, if the pattern at the field boundary is lost, the chip or the like on which the drawing is performed becomes a completely defective product.

As one method of electron beam writing, there is a method in which an electron beam is shaped into a rectangular beam, the rectangular beam is shot on a material to be drawn, and a desired pattern is drawn while shifting the shot position. . In this case, the accuracy of the connection between the adjacent rectangular patterns becomes a problem. An improved method for this is described below.

FIG. 3 shows a pattern to be drawn.
Four belt-like pattern _D 1 to D ₄ are included. This pattern data is divided in advance for each field. Line L in the figure is a field boundary, is divided into two fields F ₁ and F _2. Note that f is the length of one side of the field. For this F ₁ and F ₂ of the pattern data, two drawing pattern data is created. One drawing pattern data is shown in FIG.
As shown in (b), shots are divided into fixed size B. For the size B, the maximum length of a rectangular electron beam is used. In the other drawing pattern data, as shown in FIGS. 5A and 5B, the first left end portion is divided by a length different from B, for example, B / 2, and the subsequent portions are constant. Is divided by the size B.

After the pattern division (shot division) as described above, a rectangular electron beam is shot on the material to be drawn with respect to the pattern data shown in FIG. At this time,
Shot time of each rectangular beam (dose of electron beam)
Is one of the basic times needed to expose the resist on the material
/ 2. After drawing based on the pattern data in FIG. 4 is completed, a rectangular electron beam shot is performed on the pattern data in FIG. Also at this time, the shot time of each rectangular beam is set to の of the basic time of drawing. According to such a drawing method, the connection between shots is different between the first and second shots, so that the accuracy of connection between shots based on each rectangular beam can be improved, but the fields F ₁ , F ₂ The problem of bridging the pattern between will still remain.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to provide a pattern writing method in which a rectangular beam is shot and a pattern is drawn without increasing the number of data so much. It is an object of the present invention to realize a step-and-repeat type charged particle beam writing method that can smoothly and smoothly connect patterns straddling.

[0009]

According to a first aspect of the present invention, there is provided a step-and-repeat type charged particle beam writing method in which a material to be written is intermittently moved for each field, and a predetermined material on the material is stopped when the material is stopped. This is a step-and-repeat method in which a field pattern is drawn with a charged particle beam.A rectangular beam is shot in each field, and a pattern of a desired size is drawn while shifting the shot position. In the charged particle beam writing method to be performed, the first field and the first field
For patterns drawn over the next second field adjacent to the field , the first and second types of patterns are used.
The first type of pattern is drawn using the pattern data.
Turn data is written from one end of the pattern
1st and 1st when the width is set in units of size
Next break (fields 1 and 2)
If the field boundary and the separator match,
Each pattern obtained by dividing the pattern at the position
Use the pattern data of the first drawing pattern for each field
There, as the second type of pattern data, one end of the pattern
Approximately 1/2 of the width of the writing beam size from the first
And then use the width of the writing beam size as a unit to
Next delimiter straddling the first and second fields when attached
(The boundaries and boundaries of the first and second fields match.
If you do, the pattern is
Of the second drawing pattern for each field obtained by dividing
Using pattern data, in each field, type 1 and
Using the second type of pattern data, the first drawing pattern and the
And the second drawing pattern are separated by the above-mentioned breaks.
By shooting the image beam, the first writing pattern
And the second drawing pattern are overlapped , and the first drawing
It is characterized in that the dose amount of the charged particle beam at the time of writing the pattern and the second writing pattern is reduced to approximately 1/2 from the reference amount. The step en according to claim 2
The method of drawing a charged particle beam by a repeat method is described in claim 1.
Between the first field and the second field
On the border between the two fields.
Divided into two patterns, and for each pattern data
Attribute, and according to the attribute,
By adding and subtracting each pattern width, the first and second
It is characterized by obtaining two drawing patterns. Contract
The step-and-repeat charged particle beam according to claim 3
The method of writing a film is to transfer the material to be drawn intermittently for each field.
Movement, and when the material is stopped,
Draw patterns with charged particle beam
Step-and-repeat method, with each field
Shot a beam shaped into a rectangle with the shot
Draw a pattern of the desired size while shifting the position
In the charged particle beam writing method, the first field
And a subsequent second field adjacent to this first field.
For patterns drawn over the
Draw using one type and second type of pattern data
To, as the first type of pattern data, pattern
From one end of the drawing beam width unit
Next delimiter straddling the first and second fields when attached
(The boundaries and boundaries of the first and second fields match.
If you do, the pattern is
Of the first drawing pattern for each field obtained by dividing
Using pattern data as the second type of pattern data
From the first drawing pattern on the first field side
Also, the width of the drawing beam size is almost 1 on the second field side.
/ 2, the writing beam from one end of the pattern
After drawing approximately 1/2 of the width of the size as the first break, draw
The first file is separated by the beam size width as a unit.
The pattern data of the second drawing pattern on the
2 than the first drawing pattern on the field side
Field side is almost half of the writing beam size width
The beam size drawn from one end of the pattern
Of the second field side separated by the width of
Using the pattern data of the second drawing pattern, each feature
Uses the first and second types of pattern data.
The first drawing pattern and the second drawing pattern
To be shots of the drawing beam separated by the delimiter
Thus, the first drawing pattern and the second drawing pattern
While drawing , the first drawing pattern and the second drawing pattern
Is the dose of the charged particle beam during writing a reference amount?
It is characterized in that it has been reduced to almost 1/2. Claim
Item 4. Step-and-repeat type charged particle beam according to item 4.
The drawing method according to claim 3, wherein the first field and the
The pattern drawn over the second field is
1 The pattern width on the field side is
Divide the two patterns so that they are several times larger,
In addition, the first drawing pattern is used.
is there.

[0010]

In the step and repeat method charged particle beam writing method based on the present invention, for the pattern to be drawn straddling adjacent Ri suits field, the first type
Using the second type of pattern data, the first drawing pattern
And the second drawing pattern. In the case of the present invention, it
At the time of each drawing, all shot division positions are different
Therefore, not only the connection of shots
It is possible to smoothly connect patterns in the boundary area
When connecting, there may be extreme steps at the joints,
Is prevented from becoming impossible. Also, the data
Can be significantly reduced .

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 6 shows an example of a variable area electron beam writing apparatus for carrying out the present invention. Reference numeral 1 denotes an electron gun that generates an electron beam EB. The electron beam EB generated from the electron gun 1 is irradiated onto a first shaping aperture 3 via an illumination lens 2. The aperture image of the first shaping aperture is formed on the second shaping aperture 6 by the shaping lens 4, and the position of the image can be changed by the shaping deflector 5. The image formed by the second forming aperture 6 is irradiated onto the drawing material 10 via the reduction lens 7 and the objective lens 8. The irradiation position on the drawing material 10 is
It can be changed by the positioning deflector 9.

A computer 11 transfers pattern data from an external memory 12 such as a magnetic disk memory to a pattern data memory 13. The pattern data from the pattern data memory 13 is supplied to a data width addition / subtraction circuit 15 via a data transfer circuit 14. The output data of the addition / subtraction circuit 15 (the first type and the
The two types of pattern data) are supplied to the shot divider 16 and divided into shots. A signal corresponding to the drawing data from the shot divider 16 performs a deflection control circuit 17 for controlling the shaping deflector 5, a control circuit 18 for controlling the positioning deflector 9, and blanking of an electron beam generated from the electron gun 1. It is supplied to a blanking control circuit 20 for controlling the blanking electrode 19. Further, the computer 11 controls a drive mechanism 22 of the stage 21 on which the material is placed for moving the material on a field-by-field basis. The operation of the electron beam writing apparatus having such a configuration is as follows.

The case of drawing the pattern shown in FIG. 3 will be described as an example. The example of FIG. 3 is a case in which a pattern is connected between fields in the X direction. The computer 11 first converts the data in the memory 12, converts the data into a format for drawing with a rectangular beam, and transfers the converted pattern data to the data memory 13 for storage. At this time, the single pattern data is made into two types of pattern data, and further, the data is divided into fields,
An attribute is assigned to each pattern in the field-divided pattern data.

[0014] This attribute for the one which is divided pattern data, the pattern Q ₁ belonging to the field F ₁
Pattern _Q 5 to Q belonging to to Q ₄ and the field _{F 2
8} are assigned the attributes shown in FIG. Further, with respect to the other pattern data, the pattern _Q 5 to Q ₈ belonging to the pattern _Q 1 to Q ₄ and the field _{F 2} belonging to the fields _{F 1,} the attributes shown in FIG. 8 are attached. There are two types of attributes, a front attribute and a rear attribute.
Is the width to be added or subtracted to ₁ to Q _8. The previous attribute, when performing drawing from the field F ₁ in the order of the field F _2, an attribute relative to the portion in contact with the field F ₂ of the pattern of field F _1, the rear attribute field F ₂ pattern fields is an attribute with respect to a portion in contact with the F _1. Further, the width of the front attribute is used for adding the pattern width, and the width of the rear attribute is used for subtracting the pattern width. The attribute -1 indicates that there is no pattern connection between the fields.

The pattern data stored in the data memory 13 is sequentially read out and supplied to a data width addition / subtraction circuit 15 via a data transfer circuit 14. In the first drawing for the same pattern data, the data width addition / subtraction circuit 15 performs addition / subtraction of each pattern based on the attributes shown in FIG. FIGS. 9A and 9B show the pattern data on which the addition and subtraction have been performed. The pattern data subjected to the addition / subtraction (first type pattern data, that is,
The pattern data of the first drawing pattern is supplied to the shot divider 16. For the first drawing pattern in FIG. 9, the shot divider 16 divides each pattern by the width B from the left end. Based on the data divided by the shot divider 16, the deflection control circuit 17 controls the shaping deflector 5, and the control circuit 18 controls the positioning deflector 9.

As a result, the unit patterns are sequentially shot on the material based on the divided pattern data, and the pattern drawing shown in FIG. 9 is performed. Therefore, the patterns Q ₂ to
For Q _4, last shot is performed extends over the field _{F 1} and the field _{F 2.} Moreover, the pattern _Q 6 to Q ₈ to be connected to the pattern _Q 2 to Q ₄ are,
The minute the first shot pattern _Q 2 ~Q ₄ is protruding,
This is done away from the field edge.

At this time, the blanking signal from the blanking control circuit 20 to the blanking electrode 19 causes the irradiation time of the electron beam to the material 10 (the dose of the electron beam) to be equal to the exposure of the resist on the material. This is half of the required basic time.

After the first drawing is performed, a second drawing is performed on the same pattern data. The attributes for each pattern at this time are shown in FIG. The pattern data for the second drawing is transferred to the data transfer circuit 14.
Is supplied to the data width addition / subtraction circuit 15 through In the second drawing of the same pattern data, the data width addition / subtraction circuit 15 performs addition / subtraction of each pattern based on the attributes shown in FIG. FIG. 10 shows the pattern data on which the addition and subtraction have been performed. The pattern data subjected to the addition / subtraction (the second type of pattern data, that is, the second
The pattern data of the drawing pattern) is the shot divider 1
6. For the second drawing pattern in FIG. 10, the shot divider 16 determines that the left end of each pattern is B / 2.
The width is divided by the width B, and then the division is performed by the width B. Q5
About to Q8, division is performed by the width of B. Based on the data divided by the shot divider 16, a deflection control circuit 17
Controls the shaping deflector 5, and the control circuit 18 controls the positioning deflector 9.

As a result, each divided pattern data
The unit pattern is shot on the material in order based on
Ten patterns are drawn. Therefore, the pattern
Q₁, Q ₂, Q₄About the last shot
Ludo F₁And field F₂Is performed over Also,
This pattern Q₁, Q₂, Q₄Pattern to connect to
Q₅, Q₆, Q₈About the first shot putter
Q₁, Q₂, Q₄The end of the field
It is done apart. Note that this second drawing is also
It is executed at a dose of 1/2 of the reference dose of the material.
You.

As described above, the drawing shown in FIG. 3 is performed by dividing the pattern into two times, and at the time of each drawing, the divided positions of the shots are all different. Also, it is possible to prevent the drawing accuracy from being degraded even at the connection portion between the fields.

Next, one method for simplifying the attributes in the present invention, that is, for reducing the number of data will be described. When the pattern data of FIG. 3 is divided into fields, the division is not performed along the field boundaries but is performed at an integral multiple of the writing beam size B. FIG. 11 (a),
(B) shows the pattern data thus divided. At this time, the attributes given to each pattern data Q ₁ to Q _8, as shown in FIG. 12, only the presence or absence of data connection. The attribute 0 in FIG. 12 indicates the case without connection, and the attribute 1 indicates the case with connection.

Drawing is performed on the pattern data according to the following rules. First, in the first drawing, a normal drawing is performed without increasing or decreasing the data width. In the second drawing, the data with the post-connection is reduced by B / 2 on the right side. Also, the data with the previous connection is increased by B / 2 on the left side. Only the data without the previous connection has the first shot divided by B / 2.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, although a variable area type electron beam writing apparatus has been described as an example, the present invention can be applied to an ion beam writing apparatus. The method can be used not only for exposing the resist but also for ion implantation. Further, the present invention can be applied not only to the step-and-repeat method, but also to all methods of dividing a pattern and drawing each division. Also, for simplicity of description, only the connection of patterns in the X direction has been described, but the connection of patterns and fields in the Y direction is also performed in the same manner as in the X direction.

[0024]

As described above, in the step-and-repeat type charged particle beam writing method according to the present invention, the first and second types of pattern data are used.
When drawing the first drawing pattern and the second drawing pattern
At the time of each drawing,
Because everything is different, if only the joint part of the shot
Smooth connection of patterns at the field boundary
And the connection part has an extreme step
Therefore, it is possible to prevent the pattern from being disconnected.
Also, the amount of data can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a field and a pattern included therein.

FIG. 2 is a diagram for explaining a pattern shift at a field boundary portion.

FIG. 3 is a diagram showing a pattern to be drawn.

FIG. 4 is a diagram showing a pattern divided into shots for the first drawing.

FIG. 5 is a diagram showing a pattern divided into shots for the second drawing.

FIG. 6 shows an example of an electron beam writing system for implementing the method according to the invention.

FIG. 7 is a diagram for explaining attributes given to pattern data.

FIG. 8 is a diagram for explaining attributes given to pattern data.

FIG. 9 is a diagram showing a first drawing pattern according to the method of the present invention.

FIG. 10 is a diagram showing a second drawing pattern according to the method of the present invention.

FIG. 11 is a diagram showing pattern data according to another embodiment of the present invention.

FIG. 12 is a diagram showing attributes given to the pattern data of FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron gun 2 Illumination lens 3, 6 Molding aperture 4 Molding lens 5, 9 Deflector 7 Reduction lens 8 Objective lens 10 Material 11 Computer 12 Memory 13 Data memory 14 Pattern transfer circuit 15 Data width addition / subtraction circuit 16 Shot splitter 17 Molding deflection Control circuit 18 positioning deflector control circuit 19 blanking electrode 20 blanking control circuit 21 stage 22 drive mechanism

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 7/20

Claims (4)

(57) [Claims] 1. A step-and-repeat method in which a material to be drawn is intermittently moved for each field, and a pattern of a predetermined field on the material is drawn by a charged particle beam when the material is stopped. In a charged particle beam writing method in which a beam shaped into a rectangle is shot in each field and a pattern of a desired size is drawn while shifting the shot position, a first field and a next field adjacent to the first field are drawn. matched
For patterns to be drawn over the subsequent second field , the first and second types of pattern data are used.
There so as to draw, as the first type of pattern data, one end of the pattern
From the drawing beam size width as a unit
Next break across the first and second fields of time
If the boundaries of the first and second fields match the break
The pattern at the position of the boundary on the boundary
Of the first drawing pattern for each field obtained
Used Ndeta, as the second type of pattern data, from one end of the pattern
Approximately 1/2 of the writing beam size width is used as the first break.
After that, put a break in the unit of writing beam size width
Next break across the first and second fields
(The boundaries of the first and second fields match
The pattern on the border)
The pattern of the second drawing pattern for each field obtained by dividing
Using turn data, in each field, type 1 and type 2 pattern data
And the first drawing pattern and the second drawing pattern
Shot the drawing beam in each of the above sections
Thus, the first drawing pattern and the second drawing pattern
Together draw over, step-and-repeat manner charged particle beam, characterized in that reduced to about one half the reference amount of the dose of the charged particle beam during the drawing of the first drawing pattern and the second drawing pattern Drawing method. 2. The method according to claim 1, wherein the first field, the second field,
Is drawn on the border between both fields
Into two patterns, each pattern Data
To the attributes, and according to the attributes, both fields
By adding and subtracting each pattern width on the
And obtaining a second drawing pattern.
Step and repeat method charged particle beam writing
Method. 3. The material to be drawn is intermittently transferred for each field.
Movement, and when the material is stopped,
Draw patterns with charged particle beam
Step-and-repeat method, with each field
Shot a beam shaped into a rectangle with the shot
Draw a pattern of the desired size while shifting the position
In the charged particle beam writing method, the first field and the first field are adjacent to each other.
A putter drawn over the subsequent second field
For patterns, the first and second types of pattern data are used.
There so as to draw, as the first type of pattern data, one end of the pattern
From the drawing beam size width as a unit
Next break across the first and second fields of time
If the boundaries of the first and second fields match the break
The pattern at the position of the boundary on the boundary
Of the first drawing pattern for each field obtained
And the second type of pattern data as the first field
In the second field than the first drawing pattern in
It is reduced by almost half of the width of the writing beam size.
Approximately の of the writing beam size width from one end of the pattern
Is the first break, then the width of the writing beam size
The second drawing pattern on the first field side
Turn pattern data and the second field side
The first field side than the first drawing pattern
Is increased by almost half of the width of the
From one end of the pattern in units of the writing beam size width
Of the second drawing pattern on the second field side
Pattern data of the first and second types in each field.
And the first drawing pattern and the second drawing pattern
Shot the drawing beam in each of the above sections
Thus, the first drawing pattern and the second drawing pattern
In addition to the overlapping drawing , the first drawing pattern and the second drawing pattern
Approximately 1/2 dough's weight standards amount of the charged particle beam
Step and repeat method characterized by reduced
Type charged particle beam drawing method. 4. The method according to claim 1, wherein the first field, the second field,
The pattern drawn over the first field side
Pattern width is an integral multiple of the writing beam size.
It is divided into two patterns, which are
4. The step of claim 3, wherein the step is a turn.
And-repeat type charged particle beam writing method.