JPH0831727A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a fine pattern with high accuracy while largely improving a throughput by obtaining the area density of the pattern formed to an electron- beam photo-resist, determining a batch exposed unit region in response to the obtained area density and forming the pattern to the electron-beam photo-resist. CONSTITUTION:Area density in the exposure region of a pattern formed to an electron-beam photo-resist on a semiconductor substrate is acquired at the stage of a layout design. A partial batch exposure region 51 is determined according to formula b=k/a on the basis of the acquired area density. Where (a) represents regarding the substrate the resist, etc. That is, area density (a) is reduced, and the partial batch exposure region (b) is extended with the decrease of the modulation of the quantity of exposure within the range of exposure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, for example, a semiconductor memory device such as a DRAM,
Particularly, it relates to an electron beam exposure method.

[0002]

2. Description of the Related Art Semiconductor devices are manufactured by a number of processes, and among these many processes there are several photolithography processes. Generally, these photoengraving steps are performed by a transfer method using ultraviolet rays. That is, using an exposure mask, the exposure mask is irradiated with ultraviolet rays, the photosensitive resin coated on the semiconductor substrate is collectively irradiated with the pattern formed on the exposure mask, transfer is performed, and then the resist developing solution is applied. By developing the photosensitive resin using
A pattern is produced. However, such a transfer method using ultraviolet rays is not so fine as a pattern to be formed and is suitable for mass production, but it forms a semiconductor device having a fine pattern of a wavelength of ultraviolet rays or less. There was a problem that it was difficult.

In recent years, in the case of forming a semiconductor device having a fine pattern or in the case of forming a large number of semiconductor devices in a small amount, a manufacturing method using an electron beam wafer direct exposure technique has been considered. That is, the electron beam wafer direct exposure technique is a technique in which electrons emitted from an electron gun are focused into a desired shape by an electron lens, a diaphragm, and the like, and are moved to draw a set of fine patterns one after another. . In writing using an electron beam, a pattern can be created using data, and an exposure mask is not necessary.

However, in such an electron beam wafer direct exposure technique, since the electrons incident on the electron beam photosensitive resin are scattered, the exposure amount is insufficient for a fine pattern, and the pattern size becomes small or a large pattern is formed. In the area sandwiched between the two, the electron that is incident on the substrate is re-incident on the electron beam photosensitive resin, resulting in an excessive exposure amount, that is, a proximity effect, and a large amount of pattern data There is a problem that throughput is deteriorated because a processing method of drawing one by one is used.

One method for solving the proximity effect is described in, for example, J. Vac. Sci. Technol. B
10, Nov / Dec (1992). In other words, this J. Vac. Sci. Technol. B1
No. 0, Nov / Dec (1992), when using the electron beam wafer direct exposure technique, when the ratio of the area occupied by the pattern to be irradiated with the electron beam in the unit area is defined as the area density, the area density Depending on the size of
By changing the electron beam exposure amount by changing the irradiation time of the electron beam, the area with a small area density is exposed with a relatively large exposure amount, and the area with a large area density is exposed with a relatively small exposure amount. This is a method of preventing the deformation of the pattern due to the proximity effect by exposing with. As one method for realizing this method, it is conceivable to use the variable shaping electron beam exposure apparatus shown in FIG. 23, for example.

In FIG. 23, 1 is an electron gun for supplying electrons to be used for drawing, 16 is an electron beam bundle emitted from the electron gun 1, 2 is an extraction electrode for extracting the electron beam bundle 16 emitted from the electron gun, and 3 is An extraction voltage source 4 for supplying a voltage to the extraction electrode, 4 is an electron beam bundle 1 emitted from an electron gun.
6 is a first shaping aperture, 5 is a first deflection electrode capable of changing the traveling direction of the electron beam bundle 16 shaped by the first shaping aperture 4, and 6 is an electron beam bundle deflected by the first deflection electrode 5. 16 is a second shaping aperture, 7 is a reduction lens that can reduce the electron beam bundle 16 shaped by the second shaping aperture 6, and 8 is a first lens that can change the traveling direction of the electron beam bundle 16 that is reduced by the reduction lens 7. Two deflection electrodes, 9 is a focusing lens for focusing the electron beam bundle 16 deflected by the second deflection electrode 8, 10 is a wafer on which a photosensitive resin is applied and baked to remove the solvent, and 11 is a wafer on which the wafer 10 is moved. Is a stage that enables the lens, 12 is a lens control unit that controls the reduction lens 7 and the focusing lens 9, and 13 is a deflection electrode 5.
Deflection control means for controlling 8 and 8, and 14 is deflection control means 1
3, data control means for giving data to 3, reference numeral 15 for controlling the data control means 14 and lens control means 12, 54 for accelerating the electron beam bundle 16,
An accelerating voltage source for irradiating the wafer 10 and 55 denotes a blanking electrode for irradiating the electron beam bundle 16 on the blanking aperture indicated by 56.

Next, the operation of the variable shaped electron beam exposure apparatus having the above structure will be described. The electron beam flux is emitted from the electron gun 1 toward the extraction electrode 2 by the voltage supplied from the extraction voltage source 3. This electron beam bundle passes through the first shaping aperture 4. At this time, the shape of the cross section of the electron beam bundle is the same as the pattern drawn on the first shaping aperture plate 4. Deflection control means 13
The traveling direction of the electron beam bundle 16 is arbitrarily adjusted and changed by the first deflection electrode 5 controlled by. Next, this electron beam bundle 16 passes through the second shaping aperture 6. At this time, the cross section of the electron beam bundle 16 is controlled by the second deflecting electrode 5 so as to have a shape in which the pattern-cut portion of the first shaping aperture 4 and the pattern-cut portion of the second shaping aperture 6 are overlapped. It can be arbitrarily shaped.

Next, the electron beam bundle 16 is condensed by the reduction lens 7 controlled by the lens control means 12, and the traveling direction is irradiated to a desired position on the wafer 10 by the deflection electrode 8 controlled by the deflection control means 13. Adjusted to be possible and condensed by the focusing lens 9,
The wafer 10 coated with the electron beam photosensitive resin is irradiated. The irradiated electron beam bundle 16 is exposed by exposing the electron beam photosensitive resin. Here, the exposure amount control of the electron beam is performed by controlling the time for blocking the electron beam bundle 16 irradiated on the wafer 10 by using the blanking electrode 55 and the blanking aperture 56. The shorter the exposure time, the smaller the value. Next, the photosensitive resin is developed using a resist developing solution to form a pattern. This completes one photoengraving process.

On the other hand, as one method for improving the throughput in the exposure using the variable shaped electron beam exposure apparatus, for example, the partial collective exposure electron beam exposure apparatus shown in FIG. 28 may be used. 28, reference numerals 1 to 5 and 7 to 15 indicate the same or corresponding portions as the variable shaping electron beam exposure apparatus shown in FIG.
Reference numeral 17 indicates a stencil mask. The stencil mask 17 is one of the exposure masks used at the time of exposure, and is an exposure mask in which a circuit pattern is formed by forming holes in a thin film substrate formed of silicon or the like as shown in FIG. 31, for example.

Next, the operation of the partial collective exposure electron beam exposure apparatus thus constructed will be described. The electron beam bundle 16 is emitted from the electron gun 1 toward the extraction electrode 2 by the voltage supplied from the extraction voltage source 3.
This electron beam bundle 16 passes through the first shaping aperture 4. At this time, the cross-sectional shape of the electron beam bundle 16 is exactly the same as the pattern drawn on the first shaping aperture. The traveling direction of the electron beam is arbitrarily adjusted and changed by the first deflection electrode 5 controlled by the deflection control means 13.

Next, the electron beam bundle 16 passes through the stencil mask 17. At this time, the cross section of the electron beam bundle 16 is shaped into a shape in which the pattern portion of the first shaping aperture 4 and the pattern portion of the stencil mask 17 are overlapped. Next, the electron beam bundle 16 is moved to the lens control means 1
Condensed by a reduction lens 7 controlled by 2,
It is adjusted by the second deflection electrode 8 controlled by the deflection control means 13 so that the advancing direction can be irradiated to a desired position on the wafer 10, condensed by the focusing lens 9, and transferred onto the wafer 10 coated with the electron beam photosensitive resin. Is irradiated. The irradiated electron beam bundle 16 exposes the electron beam photosensitive resin to light, and the electron beam photosensitive resin is developed to form a pattern.

[0012]

However, the proposed example using the partial batch exposure electron beam exposure apparatus shown in FIG. 28 performs batch exposure, so that throughput can be improved, but batch exposure is not possible. Since the amount of exposure is always constant, if the area for collective exposure is increased, a proximity effect occurs, making it difficult to form a fine pattern with high dimensional accuracy. On the contrary, if the area for collective exposure is made too small, the improvement in throughput is not so improved.

The present invention has been made in view of the above points, and an object of the present invention is to obtain a method of manufacturing a semiconductor device capable of forming a fine pattern with high accuracy and greatly improving throughput. is there.

[0014]

According to a first aspect of the present invention, in a method of manufacturing a semiconductor device, particularly an electron beam exposure method, a batch exposure is performed according to an area density of a pattern formed on an electron beam photosensitive resin. It changes the area.

In the invention according to claim 2, claim 1
In addition to the invention according to (1), the area for partial collective exposure is an area in which a plurality of pattern repeating unit areas are combined.

In the invention according to claim 3, claim 2
In addition to the invention according to (1), the repeating unit area of the pattern is an area of about 0.5 to 5 μm square.

In the invention according to claim 4, claim 1
In addition to the invention according to claim 3, the region for partial batch exposure is a region of about 3.0 to 10 μm square.

According to the invention of claim 5, claim 1
In addition to the invention according to claim 1, an area in which the modulation of the correction exposure amount for correcting the proximity effect is large is exposed by using a variable shaping electron beam exposure technique which has been used conventionally, and the other portion is defined by claim 1. Exposure is performed by using the invention according to the above.

In the invention according to claim 6, claim 5
In addition to the invention according to (1), the regions to be exposed by using the variable shaped electron beam exposure technique are all the corners of the regions to be exposed.

In the invention according to claim 7, claim 5
In addition to the invention according to the first aspect, the area to be exposed by using the variable shaped electron beam exposure technique is the entire peripheral portion of the area to be exposed.

In the invention according to claim 8, claim 5
In addition to the invention according to claim 7, the region to be exposed using the variable shaped electron beam exposure technique is a region having a width of 1.0 to 10 μm from the corner of the pattern or the periphery.

In the invention according to claim 9, the repeating unit area of the pattern formed on the electron beam photosensitive resin is as large as about 3.0 to 10 μm square, and the exposure amount to be corrected within the unit area is largely modulated. If there is a portion, the area is exposed using the variable shaping electron beam exposure technique, and for other areas, a partial batch exposure electron beam is performed for each repeating unit area of the pattern formed on the electron beam photosensitive resin. A pattern is formed by performing exposure.

In the invention according to claim 10, in addition to the invention according to claim 9, the area to be exposed by using the variable shaping electron beam exposure technique is a region having a corner portion or a peripheral portion of the pattern. It is a thing.

[0024]

According to the first aspect of the present invention, the step of determining the areal density of the pattern formed on the electron beam photosensitive resin, the step of determining the unit area to be collectively exposed according to the determined areal density, By the step of forming a pattern on the beam photosensitive resin, a unit area for collective exposure is determined so that the dimensional accuracy is high and the throughput is improved as much as possible, and the pattern is formed on the electron beam photosensitive resin.

In the invention according to claim 2, claim 1
In addition to the operation of the electron beam exposure apparatus, a step of determining a repeating unit area smaller than the maximum collective exposure area of the electron beam exposure apparatus and a step of determining the area to be collectively exposed to be an integral multiple of the unit area An accurate pattern shape is exposed on the resin.

In the invention according to claim 3, claim 2
In addition to the effect of
The area of 5 μm square facilitates the determination of the area for collective exposure.

In the invention according to claim 4, claim 1
Further, in addition to the operation according to the third aspect, the area to be collectively exposed is set to about 3.0 to 10 μm square, which facilitates the determination of the area to be collectively exposed.

In the invention according to claim 5, claim 1
In addition to the operation according to, the step of determining the area to be exposed by the variable shaping electron beam exposure technique when the area for collective exposure determined from the area density is a certain value or less, and the variable shaping electron beam exposure technique. By the step of determining the partial collective exposure region when exposing a region other than the region to be exposed by, the collective exposure region larger than the region for collective exposure obtained from the area density is determined.

In the invention according to claim 6, claim 5
In addition to the operation related to the above, by making the area to be exposed by the variable shaping electron beam exposure technology a corner in the area to be exposed, it becomes easy to determine the area to be exposed by the variable shaping electron beam exposure technology. .

In the invention according to claim 7, claim 5
In addition to the operation related to the above, the region to be exposed by the variable shaping electron beam exposure technique is made to be a peripheral portion in the region to be exposed, thereby facilitating the determination of the region to be exposed by the variable shaping electron beam exposure technique. .

In the invention according to claim 8, claim 5 is provided.
In addition to the operation according to claim 7, the area to be exposed by the variable shaped electron beam exposure technique is 1.0 to 10
The area having a width of about μm facilitates the determination of the area to be exposed by the variable shaping electron beam exposure technique.

In the invention according to claim 9, the repeating unit area of the pattern formed on the electron beam photosensitive resin is as large as about 3.0 to 10 μm square, and the exposure amount to be corrected is largely modulated in the unit area. The variable shaped electron beam exposure technique is used to expose the existing regions, and the partial batch exposure electron beam exposure technique is used to expose the other regions for each repeating unit region of the pattern formed on the electron beam photosensitive resin. This facilitates the determination of the area to be exposed using the variable shaped electron beam exposure technique and the area to be exposed using the partial collective exposure electron beam exposure technique.

In the invention according to claim 10, in addition to the operation according to claim 9, the region to be exposed by using the variable shaping electron beam exposure technique is a region having a corner portion or a peripheral portion of the pattern. This facilitates the determination of the area to be exposed using the variable shaped electron beam exposure technique and the area to be exposed using the partial collective exposure electron beam exposure technique.

[0034]

【Example】

Example 1. A first embodiment of the present invention will be described with reference to FIGS. First, in order to help understanding of Example 1 of the present invention, a relationship between the position of the pattern on the wafer and the exposure amount of the electron beam when the pattern formed on the semiconductor substrate has a predetermined area density is investigated. The result of doing is explained.

FIG. 3 shows a wafer 20 having a plurality of chips 21,
This embodiment shows that there is a semiconductor memory element such as DRAM. FIG. 4 shows one chip 21 shown in FIG.
2 is an enlarged view of FIG. 1 in which memory cell arrays 22a and 22b, a peripheral circuit 23, and the like are incorporated. FIG. 5 is an enlarged view of the memory cell 22. Reference numeral 24 in the drawing denotes a region having one corner 26 of the memory cell array 22. FIG. 6 is an enlarged view of a region 24 having one corner 26 of the memory cell array 22a, and a region 25 surrounded by a broken line.
Indicates a region smaller than the maximum region in which partial collective exposure is possible, which is necessary to assist the description below.

An example of a pattern having an area density of 64% is shown in FIG. 7 using a region 27 which is several μm square from the corner 26 of the memory cell array 22a. FIG. 7 shows a case where the pattern formed on the electron beam photosensitive resin is present in the memory cell array 22a at a ratio of the area density of 64%, and the pattern 2 of 0.8 μm square is formed in the area of 1 μm square.
It shows that one 8 is present. However, here, for the sake of simplicity, the pattern 28 has a square shape,
In reality, it is considered that there are patterns of various shapes and sizes depending on the constituent parts of the semiconductor device to be manufactured.

An example of a pattern having an area density of 4% is
Region 2 of a few μm square from corner 26 of memory cell array 22a
9 is shown as shown in FIG. FIG. 8 shows a case where the pattern formed on the electron beam photosensitive resin is present in the memory cell array 22a at a ratio of the area density of 4%, and the 0.2 μm square pattern 30 is formed in the 1 μm square region. It indicates that one exists. However, although the shape of the pattern 30 is square here for simplification, in reality, it is considered that there are patterns of various shapes and sizes depending on the constituent portion of the semiconductor device to be manufactured.

Next, regarding the exposure dose in the case where the pattern formed on the electron beam photosensitive resin can be accurately formed, the case where the unit area for collective irradiation is 1 μm square and 5 μm square is measured by the area density method, for example, as described above. J. Vac. Sc
i. B10, Nov / Dec (1992) shows the results of investigations performed by the proximity effect correction by the areal density method shown in FIGS.

FIG. 9 shows an area where a pattern formed on a semiconductor substrate is a repetition of the same shape, for example, 25 μm having one corner 26 of a memory cell array 22 of a DRAM.
Represents a corner area. As is clear from FIG. 9, as a result of performing the proximity effect correction based on the above-mentioned area density method with a unit area of 1 μm square, an exposure amount that can obtain a pattern of the designed value when a line and space of 1 μm is drawn Is 100%, the corrected exposure amount is 90% at a position close to the central portion of the memory cell array 22, that is, at the position indicated by reference numeral 52 in FIG. 9, and 145 at the corner 26 of the memory cell array 22 in the drawing. The exposure amount is indicated by%. Particularly, in the area 33 of 5 μm square from the corner 26 of the memory cell array 22, the corrected exposure amount is 120 to 145%.
And the difference is 25%. Therefore, in the above case, if the proximity effect correction is performed with a square of 1 μm and the drawing is performed based on the correction, the exposure can be performed with high dimensional accuracy.

On the other hand, with the pattern having the same area density, the unit area is 5 μm square, and the proximity effect correction similar to that of FIG. 9 is performed.
The corrected exposure dose obtained is shown in FIG. As is clear from FIG. 10, the region 34 5 μm square from the corner 26 of the pattern corresponds to the region 33 5 μm square from the corner of the pattern in FIG. 9. As described above, when the unit area is 1 μm square, the corrected exposure amount of the area 33 of 5 μm square from the corner of the memory cell array is 120 to 145%, which is a 25% modulation, but when the unit area is 5 μm square. In the region 34 including the corner 26 of the memory cell array 22, the correction exposure amount is 135%.
If exposure is performed for each unit area, the unit area is 5 μm compared to the case where the unit area is 1 μm square.
The dimensional accuracy is remarkably deteriorated for m-square ones.

Next, the case where the area density of the exposure region of the pattern formed on the electron beam photosensitive resin on the semiconductor substrate is 4% will be described. In this case as well, similar to FIGS. 9 and 10, the investigation results of the corrected exposure amount when the proximity effect is corrected using the 1 μm square as the unit area and when the proximity effect is performed using the 5 μm square as the unit area are shown. This is shown in FIGS.
As is apparent from FIG. 11, the correction exposure amount is 17 in the corner 35 of the memory cell array 22 and the region 40 of 5 μm square from the corner.
5%, which is the position 3 near the center of the memory cell array 22
The corrected exposure amount of No. 6 is 170%. Therefore, at the position 36 near the center of the memory cell array 22 and the corner 35, the corrected exposure amount is modulated by only 5%.

On the other hand, FIG. 12 shows the result of the proximity effect correction using a 5 μm square unit area. As is apparent from this, the correction exposure doses at the corners 35 of the memory cell array 22 and the positions 36 near the center of the memory cell array 22 are each 1
70% and 175%, and the difference is as small as 5%. Therefore, even if the unit area of 1 μm square is collectively exposed, it is 5 μm.
Even if the corners are used as a unit area and exposed at one time, the dimensional accuracy is good in any case. Furthermore, 5 μm
It is also apparent that when the corner is used as the unit area, the throughput is improved by 25 (= 5 × 5) times as compared with the case where the exposure is performed using 1 μm as the unit area.

As is apparent from FIGS. 9 to 12, when the area densities of 64% and 4% are compared, when the area density is relatively large at 64%, the unit area for collective exposure is as small as 1 μm. However, when the area density is relatively small at 4%, it is expected that the pattern dimension accuracy can be improved by forming the semiconductor device by performing the exposure by setting the unit area for collective exposure to 5 μm square, and If it is as small as 4%, the area to be exposed at once is 5 μm square and 1
Since the area is 25 (= 5 × 5) times that of the μm square,
It is possible to greatly improve the throughput.

Next, regarding a specific method of determining the partial collective exposure area, the area density in the exposure area of the pattern formed on the electron beam photosensitive resin on the semiconductor substrate was found and found in the layout design stage. Based on the areal density,
The partial collective exposure area is determined according to the following equation. b = k / a (1) where a is an area density, b is a partial collective exposure region, and k is a constant related to the substrate, resist, and the like. That is, the above equation (1)
Then, as the area density a becomes smaller and the modulation of the exposure amount becomes smaller in the exposure range, the partial batch exposure region b becomes larger and the area density a becomes larger, and the exposure amount becomes in the exposure range. When the modulation becomes larger, the partial batch exposure area b is made smaller, and thus the partial batch area b is determined so as to improve throughput as much as possible while ensuring necessary dimensional accuracy. .

However, the cell size for collective exposure is 10 μm
If the size is larger than the angle, the connection accuracy between cells and the current density distribution in the cells are deteriorated in the current electron beam drawing apparatus, the pattern dimensional accuracy is deteriorated, and the unit area for collective exposure is 3. If the size is less than 0 μm square, the throughput decreases, so the repeating unit area of the pattern formed on the electron beam photosensitive resin must be larger than 3.0 μm square and smaller than 10 μm square.

Based on such an idea, a concrete method of manufacturing a semiconductor device will be described with reference to FIGS. In general, the semiconductor manufacturing process is as shown in FIG.
First, market research will identify the specifications users need. Next, a circuit is designed based on this specification,
The layout design of the pattern to be transferred onto the wafer is performed based on the above circuit design and technical restrictions.

When the layout is designed, for example, D
The area density of the charge storage electrode (capacitor) and the area density of the wiring connection hole (contact hole) region of the memory cell of the RAM are obtained, and the values are 64% and 4%, respectively.
It was When the partial collective exposure region b depending on the equation (1) is determined according to this area density, the partial collective exposure region b
Are determined as shown in FIGS. 1 and 2, respectively. In FIG. 2, the collective exposure region 38 at the time of exposing the pattern for forming the contact hole region having the area density of 4% is
2 of the collective exposure region 37 at the time of exposing the pattern for forming the capacitor having the areal density of 64% shown in FIG.
It is shown to be five times larger. Also,
In FIG. 1, 31 indicates a pattern for forming a gate, and 32 in FIG. 2 indicates a pattern for forming a source diffusion region.

Next, a mask is formed by making a hole in the thin film substrate which will be the stencil mask so as to leave a region other than the exposure pattern portion in the partial collective exposure region b of the capacitor. Further, a stencil mask 39 is formed on the same mask by forming a hole for forming a contact hole region in the partial collective exposure region, as shown in FIG. In the stencil mask 39, the mask forming mask portion 41 and the contact forming mask portion 42 are formed so as not to overlap with each other.

The stencil mask 39 is mounted on the partial collective exposure apparatus shown in FIG. In FIG. 15, FIG.
The same reference numerals as those given to the partial collective exposure apparatus shown in (2) indicate the same or corresponding portions.

Next, regarding the manufacturing method in the case of forming a pattern for forming the capacitor of the memory cell array on the photosensitive resin coated on the wafer, the electron beam photosensitive resin is coated and baked to remove the electrons. The wafer 10 from which the solvent of the beam photosensitive resin has been removed is placed on the stage 11, and the electron beam bundle 16 is directed from the electron gun 1 toward the extraction electrode 2 by the voltage supplied from the extraction voltage 3.
Is released. This electron beam bundle 16 passes through the first shaping aperture 4. At this time, the cross-sectional shape of the electron beam bundle 16 is exactly the same as the pattern drawn on the first shaping aperture. The traveling direction of the electron beam is arbitrarily adjusted and changed by the first deflection electrode 5 controlled by the deflection control means 13.

Next, as shown in FIG. 16, this electron beam bundle 16 is adjusted so as to hit the mask forming mask portion 41 of the stencil mask 39, and then passes through the stencil mask 39. At this time, the cross-section of the electron beam bundle has a pattern of the first shaping aperture 4 and the stencil mask 3.
The gate forming mask portion 41 of 9 is shaped to be overlapped. Next, the electron beam bundle 16 is condensed by the reduction lens 7 controlled by the lens control means 12, and the traveling direction can be irradiated to a desired position on the wafer 10 by the second deflection electrode 8 controlled by the deflection control means 13. The electron beam photosensitive resin is applied to the wafer 10 coated with the electron beam photosensitive resin. The irradiated electron beam bundle 16 exposes the electron beam photosensitive resin to light, and the electron beam photosensitive resin is developed to form a pattern for forming a capacitor. By repeating this operation, exposure is sequentially performed in the direction of arrow 50 as shown in FIG. 17 to form a pattern for forming a capacitor of the memory cell array. FIG.
In FIG. 7, reference numeral 51 indicates an area for collective exposure.

Next, a pattern for forming a contact hole is formed in the same manner as in forming a pattern for forming a capacitor. First, there is a manufacturing method for forming a pattern for forming a contact hole of a memory cell on a photosensitive resin applied on a wafer. The electron beam photosensitive resin is applied and baked to remove the solvent of the photosensitive resin. The blown wafer 10 is placed on the stage 11, and the electron beam bundle 16 is emitted from the electron gun 1 toward the extraction electrode 2 by the voltage supplied from the extraction voltage source 3. This electron beam bundle 16 passes through the first shaping aperture 4. At this time, the cross-sectional shape of the electron beam bundle 16 is exactly the shape of the hole formed in the first molding aperture 4. The traveling direction of the electron beam bundle is arbitrarily adjusted and changed by the first deflection electrode 5 controlled by the deflection control means 13.

Next, as shown in FIG. 20, this electron beam bundle 16 is adjusted so as to hit a mask portion 42 for forming a contact hole of the stencil mask 39, and passes through the stencil mask 39. At this time, the electron beam bundle 16
The cross section of is shaped into a shape in which the pattern portion of the first shaping aperture 4 and the contact hole forming mask portion 42 of the stencil mask 43 are overlapped. Next, the electron beam bundle 16 is condensed by the reduction lens 7 controlled by the lens control means 12, and the traveling direction can be irradiated to a desired position on the wafer 10 by the second deflection electrode 8 controlled by the deflection control means 13. The electron beam photosensitive resin is applied to the wafer 10 coated with the electron beam photosensitive resin. The irradiated electron beam bundle 16 exposes the electron beam photosensitive resin to light, and the electron beam photosensitive resin is developed to form a pattern for forming contact holes. Repeat this work,
As shown in FIG. 17, exposure is sequentially performed in the arrow direction to form a pattern for forming a contact hole in the memory cell array. In the first embodiment, the exposure is performed in the order of forming the capacitor and then the contact hole, but the process may be reversed depending on the type of product to be manufactured.

Example 2. Embodiment 2 of this invention is Embodiment 1
Will be described with reference to FIGS. 19 to 20. In the first embodiment, the partial collective exposure area b is determined and exposure is performed according to the equation (1), that is, b = k / a. However, when it is necessary to expose the pattern 43 as shown in FIG. 19, for example. In FIG. 19, a range 18 surrounded by a broken line is determined as a partial collective exposure region, and when exposure is performed, a pattern as shown in FIG. 20 is exposed on the photosensitive resin,
The accurate shape cannot be exposed.

Therefore, in the layout design stage,
As shown in FIG. 19, if the minimum repeating unit area 19 that is smaller than the maximum collective exposure area is determined, the above problem can be solved. That is, when the symbol 19 is the minimum repeating unit area in FIG. 19 and n is an integer, b = k / a ... (1) b = nc ... (2) Partial collective exposure area b so as to satisfy the above two expressions. , The partial collective exposure area b is always the repeating unit area c.
Therefore, it is considered that the pattern shape is not incomplete and the calculation time for determining the partial collective exposure region b is shortened.

However, as described in the first embodiment, when the cell size for collective exposure becomes 10 μm square or more, the connection accuracy between cells and the pattern dimensional accuracy decrease, and
Since throughput decreases when the unit area for collective exposure is 3.0 μm square or less, the repeating unit area of the pattern formed on the electron beam photosensitive resin must be larger than 3.0 μm square and smaller than 10 μm square. . Further, the minimum repeating unit area c has a size of 0.5 μm square or more even with the smallest memory cell in the present technology, and the dimensional accuracy becomes low if the minimum repeating unit area c is too large. Considering 0.5 ~ 5μ
It is desirable that the area is m-square.

A stencil mask in which the mask pattern of the partial batch exposure region determined as described above is drawn is prepared, and the above stencil mask is set in the partial batch exposure electron beam exposure apparatus described in the first embodiment. Exposure is performed in the same manner as.

Example 3. A third embodiment of the present invention will be described with reference to FIGS. 9, 14, 21 to 23, and 30. First, in order to help understanding of Example 3 of the present invention,
The results of an examination of the relationship between the area of the pattern formed on the electron beam photosensitive resin on the semiconductor substrate and the exposure amount of the electron beam with respect to the position will be described.

As described in the first and second embodiments, when the area density is relatively large, the area capable of partial batch exposure becomes narrow, and the area capable of partial batch exposure is about 3.0 μm square or less. In such a case, the dimensional accuracy can be secured, but the throughput is significantly deteriorated. Further, when the partial collective exposure area exceeds 10 μm square, the throughput is improved, but the variable unit area of the exposure amount for the proximity effect correction becomes too large, the correction accuracy deteriorates, and the pattern dimensional accuracy decreases. However, the exposure for improving the dimensional accuracy without lowering the throughput is performed by using different methods for the case where the region where the corrected exposure amount is largely modulated and the region where the correction exposure amount is not so modulated are respectively used. It can be realized by performing.

In FIG. 9, it has been revealed that the portion where the exposure amount to be corrected is largely modulated is in the range of about 1 to 10 μm from the corner of the memory cell array and the periphery to the center of the memory cell array. Therefore, based on these things, the corner 26 of the memory cell array in FIG. 21 showing the region having one corner of the memory cell array,
And a range 44 of about 1 to 10 μm from the periphery is exposed by the variable shaped electron beam exposure technique described in the prior art, and the region near the center of the memory cell array is formed by the partial collective exposure method described in the first embodiment. Expose. At this time, since the modulation of the exposure amount to be corrected is small in the area near the center of the memory cell array, the batch exposure area can be set larger than the batch exposure area obtained from the area density.

When the corrected exposure amount is largely modulated only in a region of a few μm square from the corner 26 of the memory cell array, as shown in FIG. 22, the corner 26 of the memory cell array is shown.
Only the area 46 of several μm square is the area to be exposed by using the variable shaped electron beam exposure technique, and when the corrected exposure amount is largely modulated in the peripheral portion of the memory cell array, By exposing the area using the variable-shaped electron beam exposure technique, the exposure can be performed with high dimensional accuracy without lowering the throughput.

As described above, when the variable shaped electron beam exposure technique and the partial collective exposure electron beam exposure technique described in Embodiments 1 and 2 are required in the same process,
In the partial collective exposure electron beam exposure shown in FIG. 4, a stencil mask 39 used for electron beam exposure is provided with one rectangular hole, and a stencil mask 45 capable of variable shaped electron beam exposure is provided as shown in FIG. Exposure is performed using the rectangular portion 53 of the stencil mask 45 as a substitute for the second shaping aperture 6 of the shaping electron beam exposure apparatus. It does not matter which of the partial collective exposure electron beam exposure and the variable shaped electron beam exposure is performed first.

Example 4. A fourth embodiment of the present invention will be described with reference to FIGS. 5 and 24 to 27. In the above-described third embodiment, in the pattern design stage, as shown in FIG. 24, the repeating unit area 47 of the pattern formed on the electron beam photosensitive resin is determined to be smaller than the maximum collective exposure area.

However, as shown in FIG. 26, when the repeating unit area 42 of the pattern formed on the electron beam photosensitive resin at the time of layout design is as large as about 3.0 to 10 μm square, correction for proximity effect correction is performed. It is conceivable that the exposure amount may be greatly modulated within one repeating unit area. In this case, the variable unit electron beam exposure technique is used to perform exposure in the repeating unit area in which the corrected exposure amount is largely modulated, and for the other areas, the partial collective exposure electron beam is formed for each repeating unit area 47. Exposure is performed according to the exposure method.

FIG. 25 shows, for example, a region 24 having one corner 26 of a memory cell array of a DRAM and showing a portion corresponding to 24 in FIG. Further, in FIG. 25, 48 is also a repeating unit region having one corner 26 of the pattern formed on the electron beam photosensitive resin. When the correction exposure amount is largely modulated in the repeating unit area 48 having one corner of the memory cell portion of the DRAM as described above, as shown in FIG. 26, the repeating unit having one corner 26 is formed. A portion of the region 48 is exposed using the variable shaped electron beam exposure technique.

When the correction exposure amount is largely modulated in the peripheral portion of the DRAM memory cell array,
As shown in FIG. 27, the inside of the repeating unit region 49 forming the peripheral portion is exposed by the variable shaping electron beam exposure technique.

By performing exposure by the method as described above, the throughput of semiconductor device manufacturing, especially the throughput of the photolithography process is significantly improved as compared with the conventional one, or the dimensional accuracy is higher than the conventional one without impairing the throughput. Exposure can be performed.

[0068]

As described above, according to the first aspect of the invention, in the method of manufacturing a semiconductor device, particularly in the electron beam exposure method, the area for collective exposure is changed according to the area density of the exposed pattern. By doing so, it is possible to perform exposure with high dimensional accuracy, and it is possible to improve throughput by collectively exposing as large a range as possible.

In addition to the effect of the invention according to claim 1, the invention according to claim 2 sets the area for partial batch exposure to an integral multiple of the repeating unit area of the pattern formed on the electron beam photosensitive resin. Thus, it is expected that the partial batch exposure region can be easily determined and that the electron beam photosensitive resin can be accurately exposed in the shape of a pattern.

According to the invention of claim 3, in addition to the effect of the invention of claim 2, the size of the repeating unit area of the pattern formed on the electron beam photosensitive resin is determined, so that the area of partial batch exposure can be achieved. It is expected that the decision will be easier.

According to the invention of claim 4, in addition to the effects of the invention of claims 1 to 3, the range of the size of the area for partial batch exposure can be determined, and thus the partial batch exposure area can be further improved. It can be expected that the decision will be easy.

According to a fifth aspect of the present invention, in addition to the effects of the first aspect, when the proximity effect correction of the exposure pattern is performed, the portion where the exposure amount to be corrected is largely modulated is the electron beam wafer directly. By exposing using the exposure technology, deterioration of dimensional accuracy is prevented, and for the area where the exposure amount to be corrected is hardly modulated, set the partial batch exposure area as large as possible, perform exposure, and The effect of improvement can be expected.

According to the invention of claim 6, in addition to the effect of the invention of claim 5, when the proximity effect correction is performed, an area where the exposure amount to be corrected has the largest modulation, that is, a corner of the area to be exposed It is expected that the parts are exposed by using the electron variable shaping electron beam contact exposure technique, and the other regions are exposed by the partial collective exposure electron beam with high dimensional accuracy and the throughput is improved.

According to the invention of claim 7, in addition to the effect of the invention of claim 5, all the areas where the exposure amount to be corrected has the largest modulation when the proximity effect is corrected, that is, all the areas to be exposed. The peripheral part is the region exposed by the variable shaping electron beam exposure technique, and the other region is the region exposed by the partial collective exposure electron beam exposure technique, thereby performing the exposure with high dimensional accuracy and improving the throughput. Can be expected.

In addition to the effects of the inventions of claims 5 to 7, the invention according to claim 8 further limits the area to be exposed by using the variable shaping electron beam exposure technique, thereby exposing with high dimensional accuracy. The effect of improving the throughput can be expected.

The invention according to claim 9 can be expected to have an effect of exposing with high dimensional accuracy and improving throughput.

In addition to the effect of the invention of claim 9, the invention according to claim 10 further limits the area to be exposed by using the variable shaping electron beam exposure technique, thereby exposing with high dimensional accuracy and improving throughput. The effect of making it possible can be expected.

[Brief description of drawings]

FIG. 1 is a diagram showing a partial collective exposure region for explaining a first embodiment of the present invention.

FIG. 2 is a diagram showing a partial collective exposure region for explaining the first embodiment of the present invention.

FIG. 3 is a plan view of a wafer necessary to help understand an embodiment of the present invention.

FIG. 4 is an enlarged view of a chip necessary to help understand an embodiment of the present invention.

FIG. 5 is an enlarged view of a memory cell array necessary for helping understanding of an embodiment of the present invention.

FIG. 6 is an enlarged view with one corner of a memory cell array necessary to help understand an embodiment of the present invention.

FIG. 7 is a conceptual diagram of a pattern having an area density of 64% necessary for helping understanding of an embodiment of the present invention.

FIG. 8 is a conceptual diagram of a pattern having an area density of 4% necessary for helping understanding of an embodiment of the present invention.

FIG. 9 is a diagram showing a corrected exposure amount when the area density required to help understanding of the embodiment of the present invention is 64%.

FIG. 10 is a diagram showing a corrected exposure amount in the case where the area density required to help understand the embodiment of the present invention is 64%.

FIG. 11 is a diagram showing a corrected exposure amount when the area density required to help understanding of the embodiment of the present invention is 4%.

FIG. 12 is a diagram showing a corrected exposure amount in the case where the area density required to help understanding of the embodiment of the present invention is 4%.

FIG. 13 is a diagram showing a manufacturing process of a semiconductor device necessary for helping understanding of the embodiment of the present invention.

FIG. 14 is a diagram showing a stencil mask necessary for explaining Embodiment 1 of the present invention.

FIG. 15 is a diagram showing a partial collective exposure electron beam exposure apparatus necessary for helping understanding of an embodiment of the present invention.

FIG. 16 is a diagram showing gate formation by partial collective exposure electron beam exposure necessary for helping understanding of the embodiment of the present invention.

FIG. 17 is a diagram showing an exposure sequence in partial batch exposure electron beam exposure in the same step necessary for helping understanding of the embodiment of the present invention.

FIG. 18 is a diagram showing formation of a source diffusion region by partial blanket exposure electron beam exposure necessary for helping understanding of an embodiment of the present invention.

FIG. 19 is a diagram necessary for explaining a second embodiment of the present invention.

FIG. 20 is a diagram necessary for explaining Embodiment 2 of the present invention.

FIG. 21 is a diagram necessary for explaining a third embodiment of the present invention.

FIG. 22 is a diagram necessary for explaining Embodiment 3 of the present invention.

FIG. 23 is a diagram showing a conventional variable shaping electron beam exposure apparatus.

FIG. 24 is a diagram necessary for explaining a fourth embodiment of the present invention.

FIG. 25 is a diagram necessary for explaining Embodiment 4 of the present invention.

FIG. 26 is a diagram necessary for explaining Embodiment 4 of the present invention.

FIG. 27 is a diagram necessary for explaining Embodiment 4 of the present invention.

FIG. 28 is a diagram showing a conventional partial batch exposure electron beam exposure apparatus.

FIG. 29 is a view showing a conventional stencil mask used for partial batch exposure electron beam exposure.

FIG. 30 is a diagram showing a stencil mask necessary for explaining an embodiment of the present invention.

[Explanation of symbols]

1. Electron gun, 2. Extraction electrode, 3. Extraction voltage source, 4. First molding aperture, 5. First deflection electrode, 6. Second molding aperture, 7. Reduction lens,
8. Second deflection electrode, 9. Focusing lens, 10. Wafer, 11. Stage, 12. Lens control means, 1
3. Deflection control means, 14. Data control means,
15. Control computer, 16. Electron beam bundle, 17. Stencil mask, 18. 19. Partial collective exposure region obtained from area density, Minimum repeating unit area, 20. Wafer, 21. Chip, 22. Memory cell array, 2
3. Peripheral circuit, 24. 25. Region having one corner of memory cell array, 25. 26. Partial batch exposure An area narrower than the maximum area where electron beam exposure is possible, 26. A corner of the memory cell array, 27. 29. A region of several μm square from a corner of the memory cell array, 28.0.8 μm square pattern, 29. Area of several μm square from corner of memory cell array, 30.0.2 μ
m-square pattern, 31. 32. A pattern for forming a gate having an area density of 64%. 33. A pattern for forming a source diffusion region having an area density of 4%, 33. 34. A region of 5 μm square from the corner of the memory cell array, 34. A region including a corner of the memory cell array, 35. A corner of the memory cell array, 36. Position near the center of the memory cell array,
37. 38. Partial collective exposure region when the area density is 64%. 39. Partial collective exposure region when the area density is 4%. Stencil mask, 40. 41. A region of 5 μm square from the corner of the memory cell array, 41. Exposure mask portion for gate formation, 42. An exposure mask for forming a source diffusion region, 43. Exposure pattern, 44. 45. A region occupying about 1 to 10 μm from the periphery to the center of the memory cell array, 45. Stencil mask, 46. A region of a few μm square from the corner of the memory cell array, 47. A repeating unit area of the memory cell array, 48. A repeating unit area having one corner of the memory cell array, 49. A repeating unit region constituting a peripheral portion of the memory cell array, 50.
An arrow indicating the order of performing exposure, 51. Partial collective exposure region, 52. Position near the center of the memory cell array, 5
3. Rectangular hole, 54. Accelerating voltage source, 55. Blanking electrode, 56. Blanking aperture.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/8242 27/108

Claims (10)

[Claims] 1. A step of determining an areal density of a pattern formed on an electron beam photosensitive resin, a step of determining a unit area to be collectively exposed according to the obtained area density, and a step of existing in the unit area to be collectively exposed. A method of manufacturing a semiconductor device, comprising the step of irradiating an electron beam to each of the unit areas through a stencil mask on which a pattern is drawn to form a pattern on the electron beam photosensitive resin. 2. A step of obtaining an areal density of a pattern formed on an electron beam photosensitive resin, a step of determining a repeating unit area smaller than a maximum collective exposure area of an electron beam exposure apparatus, and Accordingly, the step of determining the area for collective exposure to be an integral multiple of the unit area, and the predetermined exposure amount for each unit area through the stencil mask depicting the pattern existing in the unit area for collective exposure And a step of forming a pattern on the electron beam photosensitive resin, the method for manufacturing a semiconductor device. 3. The method for manufacturing a semiconductor memory device according to claim 2, wherein the repeating unit region is a region of about 0.5 to 5 μm square. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the area for collective exposure is an area of about 3.0 to 10 μm square. 5. A step of obtaining an areal density of a pattern formed on an electron beam photosensitive resin, a step of deciding an area for collective exposure according to the obtained area density, and a step of setting the area for collective exposure to 1.0 In the case of about 3.0 μm square, the step of determining the area to be exposed by the variable shaping electron beam exposure technique, and the partial batch at the time of exposing the area other than the area to be exposed by the variable shaping electron beam exposure technique The step of determining the exposure area and the electron beam exposure of irradiating the partial batch exposure area with an electron beam having a predetermined exposure amount through a stencil mask in which a pattern existing in the area for the partial batch exposure is drawn. A method of manufacturing a semiconductor device, comprising a step of forming a pattern on a resin. 6. The method of manufacturing a semiconductor device according to claim 5, wherein the region to be exposed by the variable shaping electron beam exposure technique is a corner portion in the region to be exposed in the same process. 7. The method of manufacturing a semiconductor device according to claim 5, wherein the region to be exposed by the variable shaped electron beam exposure technique is a peripheral portion of the region to be exposed in the same process. 8. The region to be exposed by the variable shaping electron beam exposure technique is a region having a width of about 1.0 to 10 μm according to the areal density of the pattern formed on the electron beam photosensitive resin. 8. The method for manufacturing a semiconductor device according to claim 6 or 7. 9. When the repeating unit area of the pattern formed on the electron beam photosensitive resin is as large as about 3.0 to 10 μm square, the step of determining the areal density of the pattern formed on the electron beam photosensitive resin, According to the area density, a step of determining an exposure method in the repeating unit area of the pattern, and a pattern existing in the repeating unit area of the pattern is determined by the determined exposure method for each repeating unit area through a stencil mask. The electron beam having a predetermined exposure amount is formed by irradiating an electron beam having a predetermined exposure amount to form a pattern on the electron beam photosensitive resin or a pattern existing in the repeating unit area is formed by using a variable shaping electron beam exposure technique. And a step of forming the electron beam photosensitive resin on the electron beam photosensitive resin. 10. If the repeating unit area of the pattern formed on the electron beam photosensitive resin is as large as about 3.0 to 10 μm square, the step of determining the areal density of the pattern formed on the electron beam photosensitive resin; When the area density is equal to or more than a predetermined value, the exposure method uses the partial batch exposure electron beam exposure technology and the variable shaping electron beam exposure technology, and the exposure is performed in the same process by using a plurality of repeating unit areas of the above pattern. The repeating unit area forming the corner or the peripheral part of the area to be exposed is exposed by the variable shaping electron beam exposure technique,
A method of manufacturing a semiconductor device, comprising the step of exposing the remaining repetitive unit regions by a partial batch exposure electron beam exposure technique.