JP2825266B2 - Writing accuracy evaluation method for pattern writing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a charged beam writing evaluation method, and particularly to a semiconductor integrated device such as an LSI drawn by a charged beam on a sample such as a mask or a wafer. The present invention relates to a method for evaluating a circuit pattern.

(Prior Art) With the advance of semiconductor technology, higher speed and higher integration of semiconductor devices have been promoted.

Along with this, the necessity of pattern miniaturization has been increasing, and high-precision pattern formation to a line width of 0.25 μm and 0.1 μm has been required.

In such a fine device, it is difficult to form a pattern using an optical stepper which has been widely used in the past, and there is a strong demand for a lithography means capable of forming a pattern with higher precision.

Above all, charged beam lithography is attracting attention as the most promising method.

In the charged beam lithography, a variable shaped beam (VSB) method using a variable shaped beam has been adopted for the purpose of improving sleep.

Conventionally, the variable shaped beam has been mainly a rectangular beam, but recently, a triangular beam has begun to be used as a means for writing a pattern including oblique lines at high speed and with high accuracy.

Here, in order to draw a good pattern with high accuracy by adjusting a beam shift caused by a slight shift of an optical lens barrel or a control portion of the drawing apparatus, the pattern is evaluated under a certain standard. Various methods have been tried.

However, when a triangular beam is used, the control portion of the drawing apparatus becomes more complicated than when a conventional rectangular beam is used alone, and a sufficiently high-precision evaluation is performed on a pattern drawn using such a apparatus. Could not be performed.

(Problems to be Solved by the Invention) As described above, in the conventional charged beam drawing evaluation method, there is a limit to the evaluation of the triangular beam.

Also, there is a problem that there is no evaluation method that can easily perform high-precision evaluation with respect to rectangular beam evaluation.

The present invention has been made in view of the above circumstances, and has as its object to provide a method that can easily evaluate a triangular beam and a rectangular beam with high accuracy.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the above object, the invention according to claim 1 draws a horizontal pattern using a rectangular beam, and uses a triangular beam to form an oblique line having an inclination with respect to the horizontal pattern. In a writing accuracy evaluation method of a pattern writing apparatus for writing a pattern, the pattern writing apparatus is used to continuously irradiate the triangular beam onto a substrate to be processed, thereby writing a diagonal pattern in which a plurality of triangular patterns are connected. A hatching pattern drawing step, and a drawing precision deriving step of observing a connection state of the triangular patterns drawn in the diagonal pattern drawing step and obtaining a drawing accuracy of the triangular beam. On the basis of,
The drawing accuracy of the pattern drawing apparatus is evaluated.

According to a second aspect of the present invention, there is provided a method for evaluating a drawing accuracy of a pattern drawing apparatus that draws a horizontal pattern and a diagonal pattern having an inclination with respect to the horizontal pattern using a rectangular beam. Then, the rectangular beam is continuously irradiated on the substrate to be processed, and a diagonal pattern drawing step of drawing a diagonal pattern in which the rectangular patterns are connected, and observing a combined state of the rectangular patterns drawn in the diagonal pattern drawing step. A drawing accuracy deriving step of obtaining the drawing accuracy of the rectangular beam, based on the drawing accuracy obtained in the drawing accuracy deriving step,
The drawing accuracy of the pattern drawing apparatus is evaluated.

According to a third aspect of the present invention, there is provided a drawing accuracy evaluation method for a pattern drawing apparatus for drawing a horizontal pattern using a rectangular beam and drawing a diagonal pattern having an inclination with respect to the horizontal pattern using a triangular beam. A first diagonal pattern drawing step of continuously irradiating the triangular beam onto the substrate to be processed using the pattern drawing apparatus and drawing a diagonal pattern in which the triangular patterns are connected; and using the pattern drawing apparatus. A second oblique pattern drawing step of continuously irradiating the rectangular beam onto the substrate to be processed and drawing a diagonal pattern in which a plurality of rectangular patterns are connected; and a plurality of diagonal lines drawn in the second drawing step. A diagonal pattern selection step of selecting a diagonal pattern corresponding to the pattern width of the diagonal pattern drawn in the first drawing step from the pattern; A drawing accuracy deriving step of obtaining the drawing accuracy of the triangular beam based on the drawing accuracy of the rectangular beam that has drawn the oblique line pattern selected in the oblique line pattern selecting step. hand,
The drawing accuracy of the pattern drawing apparatus is evaluated.

According to a fourth aspect of the present invention, there is provided a method for evaluating a drawing accuracy of a pattern drawing apparatus for drawing a pattern using a rectangular beam, wherein the substrate to be processed is shifted using the pattern drawing apparatus at different widths. A continuous pattern irradiation step is performed to draw a connection pattern in which a plurality of rectangular patterns are connected in the horizontal direction, and a connection state of the rectangular patterns drawn in the connection pattern drawing step is observed. A drawing accuracy deriving step of obtaining a drawing accuracy, based on the drawing accuracy obtained in the drawing accuracy deriving step,
The drawing accuracy of the pattern drawing apparatus is evaluated.

(Operation) According to the first and second methods, it is easy to evaluate how accurately the oblique line is drawn by observing the pattern edge of the oblique line pattern in a short time.

According to the third method, the triangular beam is drawn by comparing and examining the degree of deviation of the shape of the pattern edge of the oblique line pattern formed by the triangular beam with the degree of the oblique line pattern shape formed by the reference rectangular beam. Easily done in a short time with quantitative evaluation of accuracy. For example, by composing several oblique patterns and triangular beams having different reference rectangular beam widths and comparing and examining the oblique patterns, it is possible to determine how many μm the oblique pattern of the triangular beam corresponds to the oblique beam of the rectangular beam. Can be quantitatively evaluated.

Further, according to the fourth method of the present invention, as the evaluation pattern, the deviations of different widths are sequentially formed, and the rectangular beams are linearly arranged.
By comparing and observing the drawing data and examining which size deviation it corresponds to, it is possible to quantitatively evaluate the drawing accuracy of the rectangular beam.

(Example) Hereinafter, a charged beam evaluation method according to an example of the present invention will be described in detail with reference to the drawings.

First, as shown in FIG. 1, four evaluation patterns P1, P2, P3, and P4 having different pattern widths are input to a writing control device as writing data, and the evaluation patterns are applied to a substrate surface by a charged beam to be evaluated. Is drawn on the resist film. Here, the pattern width of each evaluation patterning P1, P2, P3, P4 is set to 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, respectively. Then, each pattern surrounds the cross-shaped pattern in which the vertical line pattern and the horizontal line pattern which are respectively rectangularly divided in the center intersect, and this cross-shaped pattern, and the cross-shaped pattern forms a square which forms a part of a diagonal line. , And the diagonal pattern is composed of a number of triangular patterns combined to form an elongated rectangle.

Next, a method for evaluating the accuracy of charged beam writing using this evaluation pattern will be described.

By observing the shape of the evaluation pattern drawn on the resist film in this way, qualitative evaluation of the writing accuracy of the triangular beam can be easily performed. That is,
What is necessary is just to judge which pattern width evaluation pattern has the finishing accuracy that can be used as oblique lines.

For example, when a triangular beam that composes a diagonal pattern is drawn, if it is rotated or moved under the influence of a slight displacement of the optical lens barrel or control part, the diagonal line becomes stair-like or distorted. Qualitative beam evaluation is possible.

In addition, quantitative evaluation can be performed by comparing with the writing data of the evaluation pattern input to the writing control device.

In addition, in order to quantitatively evaluate the oblique line pattern formed by such a triangular beam, a second evaluation pattern as shown in FIG. 2 is formed, and which pattern of the second evaluation pattern is shifted. You may make it compare whether it is about the same.

In other words, the second evaluation pattern is obtained by changing the oblique line pattern of the first evaluation pattern shown in FIG.
It is formed by being divided into rectangular beams RB forming angles of degrees. That is, four evaluation patterns with different pattern widths
R1, R2, R3, and R4 are input to the drawing control device as drawing data, and drawing is performed on the resist film applied to the substrate surface by the charged beam to be evaluated. Where each evaluation pattern R
The pattern widths t of 1, R2, R3, and R4 are 0.1 μm, 0.15 μm,
0.2 μm, 0.25 μm. Each pattern has a cross-shaped pattern in which a vertical line pattern and a horizontal line pattern, each of which is rectangularly divided, intersect at the center, and a square such that the cross-shaped pattern forms a part of a diagonal line. 4 consisting of rectangular division patterns
And two oblique line patterns.

Since a rectangular beam is easier to perform quantitative evaluation than a triangular beam, quantitative evaluation is performed in advance for various beam widths, and the rectangular beam is used for evaluation of the triangular beam TB. That is, the beam width of this rectangular beam RB is 0.09 μm, 0.08 μm, 0.07 μm, 0.06 μm, 0.05 μm.
Drawing is performed by sequentially changing m, 0.04 μm, 0.03 μm, 0.02 μm, and 0.01 μm, and by comparing with these, quantitative pattern accuracy can be evaluated.

As a result of comparing the finished state of the pattern such as the position, rotation, and beam size of the drawn triangular beam in this manner, the oblique line pattern having a width of t = 0.1 μm is substantially equal to the pattern approximated to a rectangle of 0.02 μm in beam width. there were. From this, it can be seen that the finishing accuracy when using the triangular beam TB is 0.02 μm.

In addition, as the evaluation method of the second embodiment, the evaluation pattern of the rectangular division shown in FIG. 2 can be used alone for the evaluation of the rectangular beam RB as in the evaluation of the triangular beam.

Further, an evaluation method according to the third embodiment of the present invention will be described.

First, as shown in FIG. 3, four evaluation patterns having different pattern widths are input to a writing control device using F1, F2, F3, and F4 as writing data, and a resist applied to a substrate surface by a charged beam to be evaluated. Draw on the film.

For each evaluation pattern, four linear evaluation patterns F1, F2, F3, and F4 having different pattern widths are input to the writing control device as writing data, and are charged on the resist film applied to the substrate surface by a charged beam to be evaluated. To draw. Here, the pattern width t of each evaluation pattern F1, F2, F3, F4 is 0.1 μm,
0.15μm, 0.2μm, 0.25μm. In each pattern, six rectangular beam patterns RB are shifted from each other z1... Z5.
Are connected in the horizontal direction so as to form a linear shape.

At the time of evaluation, it is possible to measure by evaluating how much the deviation is different from the drawing data.

Further, as a modification of the third embodiment, the shape of each pattern is changed to a rectangle as shown in FIGS.
Other shapes are also effective.

〔The invention's effect〕

As described above, according to the method of the present invention, as an evaluation pattern, a diagonal pattern is formed by a combination of triangular beams, and charging is easily performed in a short time by a method such as observing the pattern shape of the diagonal pattern. Evaluation of beam writing can be easily performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an evaluation pattern of the first embodiment of the present invention, FIG. 2 is a diagram showing an evaluation pattern of the second embodiment of the present invention, and FIG. 3 is a third embodiment of the present invention. FIGS. 4 to 6 are views showing a modification of the pattern of the third embodiment. P1, P2, P3, P4 ... evaluation pattern, R1, R2, R3, R4 ... evaluation pattern, F1, F2, F3, F4 ... evaluation pattern, TB ... triangular beam, RB ... rectangular beam.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/027 G03F 7/20

Claims (4)

(57) [Claims] 1. A drawing accuracy evaluation method for a pattern drawing apparatus for drawing a horizontal pattern using a rectangular beam and drawing a diagonal pattern having an inclination with respect to the horizontal pattern using a triangular beam. A diagonal pattern drawing step of continuously irradiating the substrate with the triangular beam on the target substrate to draw a diagonal pattern in which a plurality of triangular patterns are connected; and a combined state of the triangular patterns drawn in the diagonal pattern drawing step. And a drawing accuracy deriving step of observing the drawing accuracy of the triangular beam. The drawing accuracy of the pattern drawing apparatus is evaluated based on the drawing accuracy obtained in the drawing accuracy deriving step. A drawing accuracy evaluation method for a pattern drawing apparatus. 2. A drawing accuracy evaluation method for a pattern writing apparatus for writing a horizontal pattern and a diagonal pattern having an inclination with respect to the horizontal pattern using a rectangular beam. A beam is continuously irradiated on the substrate to be processed, a diagonal pattern drawing step of drawing a diagonal pattern in which the rectangular patterns are connected, and observing a combined state of the rectangular patterns drawn in the diagonal pattern drawing step, A drawing accuracy deriving step of obtaining a drawing accuracy, wherein the drawing accuracy of the pattern drawing device is evaluated based on the drawing accuracy obtained in the drawing accuracy deriving process. . 3. A drawing accuracy evaluation method for a pattern writing apparatus for writing a horizontal pattern using a rectangular beam and writing a diagonal pattern having an inclination with respect to the horizontal pattern using a triangular beam. A first diagonal pattern drawing step of continuously irradiating the substrate with the triangular beam on the substrate to be processed and drawing a diagonal pattern in which triangular patterns are connected; and using the pattern drawing apparatus, the rectangular beam A second oblique line pattern drawing step of continuously irradiating the substrate to be processed and drawing a diagonal pattern in which a plurality of rectangular patterns are connected; and a plurality of diagonal pattern drawn in the second drawing step. A diagonal pattern selection step of selecting a diagonal pattern corresponding to the pattern width of the diagonal pattern drawn in the first plotting step; A drawing accuracy deriving step of obtaining the drawing accuracy of the triangular beam based on the drawing accuracy of the rectangular beam that has drawn the oblique line pattern selected in the step, based on the drawing accuracy obtained in the drawing accuracy deriving step, A drawing accuracy evaluation method for a pattern writing device, wherein the writing accuracy of the pattern writing device is evaluated. 4. A drawing accuracy evaluation method for a pattern writing apparatus for writing a pattern using a rectangular beam, wherein the rectangular beam is continuously shifted on a substrate to be processed while shifting the rectangular beam by different widths using the pattern writing apparatus. Irradiate,
A connection pattern drawing step of drawing a connection pattern in which a plurality of rectangular patterns are connected in the horizontal direction; and a drawing accuracy deriving step of observing a connection state of the rectangular patterns drawn in the connection pattern drawing step and obtaining a drawing accuracy of the rectangular beam. The drawing accuracy of the pattern drawing apparatus is evaluated based on the drawing accuracy obtained in the drawing accuracy deriving step. A drawing accuracy evaluation method for a pattern drawing apparatus characterized by the above-mentioned.