JPH0622197B2 - Drawing method and device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a technique for drawing a fine figure by using a particle beam, and particularly to a technique suitable for realizing a high drawing precision in a drawing technique using a variable shaped beam.

[Background technology]

In a device for drawing a fine figure using charged particles such as electrons or ions, a changer is arranged in the middle of two apertures, and a variable shaped beam for arbitrarily changing the size of the beam irradiating a sample is used. Things can be considered.

However, in this drawing device, the time required for drawing can be greatly shortened, but the beam current increases in proportion to the size of the beam, and blurring occurs due to the repulsion of the charge of each particle in the beam (Coulomb effect). Has been clarified by the present inventor.

As means for solving this problem, there can be proposed a method of drawing a peripheral portion of a figure with a small beam, a method of using a high-voltage accelerating beam in which Coulomb effect and scattering inside the resist are small.

However, it is clear by the present inventors that in such a method, the backscattering of particles deeply penetrating the inside of the sample and the characteristic change due to the rise in the resist temperature due to the beam irradiation cause a large accuracy deterioration. I was killed. In particular, when the above-mentioned high-electron accelerating beam is used, both scattering and temperature rise are large, which is a problem.

Hereinafter, this problem will be described in detail with reference to the drawings. In a drawing apparatus using a variable shaped beam, as shown in FIG. 1, a figure is divided and drawn into a size smaller than a size that can be shot by the apparatus. In this case, drawing is performed from the corner of the figure in the order as shown by Irohani in FIG. 1, and the shot time in the figure is constant.

Even when the Coulomb effect is taken into consideration, as shown in FIG. 2, the shot order and shot time are essentially the same except that the peripheral shot area is limited to a small value. Is unavoidable.

FIG. 3 is a graph showing this, in which (a) shows the intensity distribution of the irradiation beam, (b) shows the distribution of the latent image generated inside the resist, and FIG. The portion on the straight line D occurs as a figure. In this case, due to the effect of the above-mentioned scattering and temperature, the latent image distribution at the edge portion of the figure has a gentle inclination as shown by the curve E in Fig. 3 (b), and due to a slight difference in the irradiation amount and the phenomenon condition. Dimensional changes occur, and the corners of the figure are rounded.
The figure becomes inaccurate as shown by the curve in (c).

[Object of the Invention] An object of the present invention is to provide a drawing technique capable of preventing a decrease in dimensional accuracy of a figure due to electron scattering inside the resist and a temperature rise, and shortening a drawing time.

The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[Outline of Invention]

The outline of a typical invention among the inventions disclosed in the present application will be briefly described as follows.

That is, the irradiation amount for drawing the internal figure of the drawing figure is made smaller than the irradiation amount for drawing the peripheral figure, and the irradiation amount for drawing the contour part is made zero than the irradiation amount for drawing the internal figure. By reducing the size including the case, it is possible to suppress the scattering of the beam and the temperature rise and obtain an accurate drawing figure.

Next, prior to the description of the embodiments of the present invention, a technology as a premise thereof will be described with reference to FIGS. 4 to 7.

FIG. 4 is a block diagram showing a drawing device according to the base technology of the present invention. In FIG. 4, 1 is a memory for storing data relating to a desired drawing figure, 2 is a division determination circuit connected to the memory 1, 3 is a division execution circuit connected to the division determination circuit 2, and 4 is a division execution circuit 3. And a shot decomposition circuit 5 connected to the division determination circuit 2 are control circuits connected to the shot decomposition circuit 4, and the control circuit 5 sends a control signal to a drawing operation unit (lens barrel unit) not shown. Then, a predetermined drawing operation is performed.

The memory 1 in which the drawing data is temporarily stored transfers the data to the division determination circuit 2 in sequence according to a command from a control computer (not shown). The division determination circuit 2 compares the short-side dimension of the data with the reference, and if the reference value is less than the reference value, the data is sent to the shot division circuit 4, and if it exceeds the reference value, the data is sent to the division execution circuit 3. The division execution circuit 3 converts the received data into a plurality of peripheral figure M ₁ , M ₂ ... M _n having a predetermined constant width, as shown in FIG.
N _n is divided into a plurality of internal figures N ₁ , N ₂ ... N _n , the data of the divided peripheral figures M _{1 to} M _n are sent to the shot decomposition circuit 4 first, and later the internal figures N _{1 to} N _n are divided. Send data. At this time, in the data of the internal figures N _{1 to} N _n , the portion designating the exposure shot time is changed to be shorter than the shot time of the data of the peripheral figure M _{1 to} M _n and is sent.

The shot decomposition circuit 4 divides the received data into shot-capable dimensions and sends it to the shot control circuit 5.
Draws a desired figure L by controlling the beam size and shot time according to the data.

In this way, the desired drawing figure L is converted into the peripheral figure N _1-
When N _n and internal figures M _{1 to} M _n are divided and the irradiation time for drawing the internal figure is made shorter than the irradiation time for drawing the peripheral figure, the beam irradiation of the internal figure in the desired drawing figure is performed. By reducing the amount, the scattering of charged particles and the temperature rise inside the resist are suppressed. Therefore, when the intensity distribution of the irradiation beam is as shown in Fig. 6 (a), the latent image inside the resist is reduced. The distribution has a steep slope at the end of the latent image distribution, as shown in FIG. 6 (b),
Therefore, an accurate desired drawing figure L as shown in FIG. 6 (c) can be obtained.

By the way, if the irradiation time of the internal figure is shortened in order to sufficiently suppress the scattering and the temperature rise in accordance with the requirements of each drawing condition such as the characteristics of the resist, the beam acceleration voltage and the size of the drawn figure, the internal figure is reduced. Exposure amount of too small,
As shown in FIG. 7, there is a risk that a defect will occur at the center of the figure.

〔Example〕

This is prevented by the drawing method and apparatus of the present invention, the embodiment of which is shown in FIGS.

As shown in FIG. 8, it is advisable to double the outer edge contours of the internal figures N _{1 to} N _n to form the contour portion P and set the irradiation time of the contour portion P to the shortest.

That is, when the irradiation time of the contour portion P is shortened as described above, the irradiation intensity distribution of the irradiation beam becomes as shown in FIG. 9 (a), and the latent image distribution inside the resist in this case is shown in FIG. The state shown in (b) is reached, and the defect in FIG. 7 (b) is resolved.

Further, the irradiation amount in the contour portion P may be zero, that is, the shot may not be shot. In this case, the irradiation intensity distribution of the beam is as shown in FIG. 10 (a), and the latent image distribution inside the resist is as shown in FIG. 10 (b). The defect is eliminated as shown in FIG. 7 (b).

When the contour portion is not shot in this way, the number of drawing shots can be reduced and the drawing time can be shortened.

FIG. 11 is a block diagram showing an embodiment of the drawing apparatus according to the present invention, which is suitable for use in creating the contour portion P.

The difference from the case of FIG. 4 is that a double division determination circuit 6 for determining the necessity of contour double division, a contour division execution circuit 7 for executing contour division, and a data correction circuit 8 are provided. It is in.

The contour double division determination circuit 6 compares the short side dimension of the data with another reference value that is larger than the reference value used in the division determination circuit 2, and a small code gives a negative code to the data and a large one gives an affirmative code. Contour division execution circuit 7
Send to. This circuit 7 is the division execution circuit 3 of the above embodiment.
Similarly, the data of the peripheral figure M _{1 to} M _n divided is sent to the shot decomposition circuit 4. After that, in the case of a negative code, the data of the internal figures N _{1 to} N _n is rewritten with the shot time data by the previously added code to the shot disassembling circuit 4. 8 respectively. The data correction circuit 8 reduces the data size by a fixed amount for both XY, shortens the shot time or rewrites it to zero, and sends it to the shot decomposition circuit 4.
The shot decomposition circuit 4 divides the input data into shotable dimensions and sends the shot data to the shot control circuit 5. The control circuit 5 controls the beam size and the shot time according to the input data, and draws the figure having the contour portion P as shown in FIG. As a result, a latent image inside the resist as shown in FIG. 9 or 10 is obtained.

〔effect〕

(1) The irradiation dose for drawing the internal figure is smaller than the irradiation dose for drawing the peripheral figure, and it is smaller than the irradiation dose for drawing the internal figure, including the case where the irradiation dose for drawing the outline is zero. Therefore, while the beam increase is suppressed,
The scattering of the beam and the temperature rise inside the resist are suppressed, and the occurrence of blurring due to the repulsion of particles in the beam is suppressed,
The drawing accuracy is improved.

(2) In addition, since it is possible to make the slope at the end of the latent distribution steep, an accurate drawing figure can be obtained.

(3) Make the shot time of the internal figure shorter than the shot of the external figure, and further make the shot time of the contour section shorter than the shot of the internal figure, or do not perform the shot. It can be shortened.

(4) By providing the division determination circuit and the division execution circuit, if desired drawing figure data is input, predetermined division drawing can be executed without requiring complicated operations and software.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Nor.

For example, it is possible to divide desired drawing data into a peripheral figure and an internal figure in advance without using the drawing apparatus and input the data to a predetermined drawing apparatus to execute the drawing method. . However, there is a risk that the amount of input data to the drawing device will significantly increase.

Further, the means for reducing the irradiation amount of the beam is not limited to the shortening of the irradiation time, and may be the reduction of energy.

When the size (short side size) of the figure to be drawn is sufficiently small, it is not necessary to distinguish the peripheral figure from the internal figure.

In addition, when the peripheral figure is cut out, the beam for shooting the internal figure does not affect the accuracy of the drawn figure even if it is affected by blurring due to the Coulomb effect. Of course.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a drawing method, FIG. 2 is an explanatory view showing a divided figure drawing method, FIG. 3 (a) is a diagram showing the intensity distribution of an irradiation beam, and FIG. Of the latent image distribution, FIG. 4C is an explanatory diagram showing a drawing figure, FIG. 4 is a block diagram showing a drawing device as a premise of the present invention, and FIG. 5 is a drawing as a premise of the present invention. FIG. 6 (a) is a diagram showing the intensity distribution of the irradiation beam, FIG. 6 (b) is a diagram showing the latent image distribution of the resist, and FIG. 6 (c) is a diagram showing a drawing figure. FIG. 7 (a) is a diagram showing the intensity distribution of the irradiation beam, FIG. 7 (b) is a diagram showing the latent image distribution of the resist, and FIG. 8 is an embodiment of the drawing method according to the present invention. Explanatory drawing, FIG. 9 (a) is a diagram showing the intensity distribution of the irradiation beam, FIG. 9 (b) is a diagram showing the latent image distribution of the resist, and FIG. 10 (a) is the intensity distribution of the irradiation beam. Diagram, same FIG. 11B is a diagram showing the latent image distribution of the resist, and FIG. 11 is a block diagram showing an embodiment of the drawing apparatus according to the present invention. 1 ... Memory, 2 ... Division determination circuit, 3 ... Division execution circuit, 4 ... Shot decomposition circuit, 5 ... Control circuit, 6 ...
... Contour double division determination circuit, 7 ... Double division execution circuit, 8
...... Data correction circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Genya Matsuoka, 1-280, Higashi Koikekubo, Kokubunji City, Tokyo Metropolitan Research Laboratory, Hitachi, Ltd. (72) Takashi Matsuzaka, 1-280 Higashi Koikekubo, Kokubunji City, Tokyo Hitachi, Ltd. (56) References JP 55-118633 (JP, A) JP 53-120276 (JP, A) JP 52-117578 (JP, A) Actual development 59-140436 (JP , U)

Claims (4)

[Claims] 1. A drawing method for drawing a desired figure by irradiating a sample with a shape-changeable charged particle beam, wherein the desired figure is divided into a peripheral figure and an internal figure, and the internal figure is divided. Is divided into two parts, the irradiation amount for drawing the internal figure is made smaller than the irradiation amount for drawing the peripheral figure, and the irradiation amount for drawing the contour part formed by the double outline is A drawing method characterized in that the irradiation amount for drawing the contour is minimized by making the irradiation amount smaller than that for drawing the internal figure. 2. The drawing method according to claim 1, wherein the irradiation amount for drawing the contour portion is set to zero. 3. A drawing device for irradiating a sample with a shape-changeable charged particle beam to draw a desired figure, and a memory for storing data of a desired figure and a short side of the figure data from this memory. A division determination circuit for comparing a dimension with a reference value to determine that a figure having data exceeding the reference value should be divided into a peripheral figure and an internal figure, and comparing with a contour reference value larger than the reference value. For a figure of data that exceeds the contour reference value, a double division determination circuit that determines that the contour of the internal figure should be doubled, and the irradiation amount for drawing the internal figure is determined from the irradiation amount for drawing the peripheral figure. And a division execution circuit for setting the irradiation amount for drawing the contour portion to be smaller than the irradiation amount for drawing the internal figure so as to set the irradiation amount for drawing the contour portion to the minimum. Circuit Decomposing shot separation circuit shot possible dimension data of the drawing apparatus characterized by comprising a control circuit for controlling the writing operation by the data from this shot decomposition circuit. 4. The drawing apparatus according to claim 3, wherein the division execution circuit sets an irradiation amount for drawing the contour portion to zero.