JP3472564B2 - Pattern transfer mask, pattern transfer method, exposure method, method of manufacturing semiconductor device, and semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern transfer mask, a pattern transfer method, an exposure apparatus, a semiconductor manufacturing method and a semiconductor device. More specifically, the present invention relates to a pattern transfer mask and a pattern transfer method capable of correcting a variation in the pattern position caused by distortion of the pattern transfer mask, a semiconductor manufacturing method using the same, and a semiconductor device. is there.

[0002]

2. Description of the Related Art In recent years, miniaturization of semiconductor integrated circuits has progressed rapidly, and in order to form finer patterns,
Research and development of next-generation lithography, which replaces the conventionally used pattern transfer method (photolithography) using light, is being actively conducted.

A transfer method using an electron beam, EPL (El
ectron Projection Lithography) is a leading candidate for next generation lithography. The EPL is roughly classified into a reduction projection exposure system and a 1 × proximity transfer system. Compared with the reduction projection exposure method, the equal-magnification transfer method has advantages that the apparatus configuration can be simplified and higher throughput can be obtained. The method disclosed as one of the equal-magnification transfer methods includes a low energy electron beam proximity exposure method (LEEPL:
Low Energy Electron-beam Proximity projection Lith
(ography) (Journal of Vacuum Science & Technology
B, Vol.17, No6, p2897-p2902). Hereinafter, LEELP will be described as a typical example of the present invention.

FIG. 8 shows a low energy electron beam proximity exposure (L
EEPL: Low Energy Electron-beam Proximity proje
It is a cross-sectional schematic diagram for demonstrating the structure of the apparatus used for (ction lithography).

In FIG. 8, an electron beam 20 emitted from an electron beam emission source (cathode) 21 is indicated by an arrow.
Passes through the focusing electromagnetic field 23 and is focused into a parallel beam. The unnecessary portion of the electron beam 20 converged into the parallel beam is blocked by the limiting diaphragm 24. The electron beam 20 is swung by the main deflector 25A toward the target to be irradiated with the electron beam 20, and then swung back by the main deflector 25B so as to be parallel to the optical axis L. As a result, the electron beam 2
0 irradiates the stencil mask 300 almost vertically,
The pattern formed on the stencil mask 300 is transferred to a resist (not shown) on the semiconductor wafer 29.

By the way, a stencil mask 300 which is a pattern transfer mask used in LEEPL.
Is composed of a membrane region 2 made of a thin film of silicon or diamond having a thickness of about 0.5 μm, and a supporting substrate 1 supporting the membrane region 2. Also, the membrane area 2
A pattern is formed in the stencil holes as through holes.

In such a thin film mask having a thickness of less than 1 μm, the thin film serving as a mask substrate is easily deformed by the release of external force and internal stress, so that the thin film is pulled so as not to loosen. It is formed of a thin film having stress. However, as compared with a glass mask made of a glass substrate having a thickness of several mm or more, which has been conventionally used in photolithography, it is difficult for the thin film mask to obtain high-precision position accuracy.

Further, in the case of exposure by the same-magnification transfer method, the distortion of the pattern transfer mask is the same magnification and the pattern is transferred to the substrate to be processed. This is one of the more important issues than in the case of photolithography.

[0009] LEEPL is a 1 × transfer method, and a stencil mask used as a mask is a thin film having a thickness of about 0.5 μm. In particular, in the case of a stencil mask, to form a pattern by opening a stencil hole in the thin film itself to be the mask substrate, when the stencil hole is opened, the internal stress applied to prevent loosening of the thin film is released, Deformation of the thin film is likely to occur. Therefore, even if a pattern is formed by a mask drawing apparatus with high position accuracy, the position of the pattern is deformed after the stencil hole is punched. Further, this pattern deformation directly affects the substrate to be processed in the same size transfer method. Therefore, the problem of positional accuracy is an important issue.

In order to deal with this position accuracy problem, LE
In the EPL, the electron beam can be easily deflected by an electromagnetic field, and a measure is taken to correct this pattern position variation.

FIG. 9 is a schematic sectional view for explaining the function of the fine adjustment deflector. A method of correcting the variation in the pattern position will be described with reference to FIG. As shown by the arrow in FIG. 9, the electron beam 20 is slightly tilted by passing near the fine adjustment deflectors 26A and 26B. As a result, as shown in FIG. 9, the irradiation position of the electron beam 20 on the semiconductor wafer 29 changes by Δ. For example, the stencil mask 300 and the semiconductor wafer 2
When the proximity distance G of 9 is 50 μm, the electron beam 20 is 1 m
If rad is tilted, the irradiation position of the electron beam 20 on the semiconductor wafer 29 is Δ = 5 as compared with the case of vertical irradiation.
It changes by 0 nm. Thus, by slightly tilting the electron beam 20 using the fine adjustment deflectors 26A and 26B,
It is possible to correct the distortion of the pattern position of the mask.

The position distortion in recent thin film mask manufacturing techniques is about 10 nm, and as described above, it is possible to sufficiently correct the pattern position distortion by slightly inclining the electron beam 20. Is.

[0013]

As described above,
In LEEPL, the irradiation position of the electron beam on the semiconductor wafer is corrected by finely adjusting the irradiation angle of the electron beam. Accordingly, it is possible to deal with the distortion of the position of the pattern caused by the deformation of the stencil mask, and it is possible to measure the improvement of the position accuracy.

However, in order to finely adjust the irradiation angle in this way, the in-plane distribution of the positional distortion is obtained for each stencil mask to be used, and the pattern is transferred while adjusting the irradiation angle for each mask. There was a problem in terms of processing efficiency.

Further, as described above, the stencil mask is given tensile stress in order to suppress slack. Since the pattern is formed as a through hole on the stencil mask, the stress is released at the portion opened as the stencil hole, and the mask is distorted. This distortion does not uniformly distort the entire stencil mask. That is, since the stress release is large in a portion having a large aperture ratio, the portion is deformed more, and the portion having a small aperture ratio is less deformed. Also,
In line and space, the stencil mask has a small deformation in the direction parallel to the line and a large deformation in the vertical direction. From this, it is easily inferred that the distortion of the thin film mask causes a nonlinear component in addition to the linear component.

Conventionally, in order to improve the positional accuracy, the relative linear distortion component between the layers of the semiconductor integrated circuit has been measured by measuring the overlay accuracy of overlay exposure. However, the position of the nonlinear distortion has not been measured, and the nonlinear distortion could not be corrected.

Therefore, the present invention suppresses the deformation of the pattern formed on the substrate to be processed due to the distortion of the pattern transfer mask without lowering the processing efficiency, and transfers the pattern faithful to the designed pattern. It proposes a method that makes it possible to do.

[0018]

A pattern transfer mask according to the present invention is a pattern transfer mask in which a pattern is formed as a through hole provided in a substrate and the pattern is transferred to a substrate to be processed by irradiation of a charged particle beam. A mask,
The pattern includes a plurality of unit patterns arranged at a predetermined gap, said unit patterns, said unit Pa
It includes a position measurement pattern arranged in the turn and used for measuring the coordinate position on the pattern transfer mask.

[0019]

The pattern transfer mask of the present invention is a pattern transfer mask in which a pattern is formed as a through hole provided in a substrate, and the pattern is transferred to a substrate to be processed by irradiation of a charged particle beam. , The pattern includes a position measurement pattern used to measure coordinate positions on a pattern transfer mask, and the position measurement pattern is transferred to a substrate to be processed to form a semiconductor device.
It is an element that constitutes a pattern .

Further, in the pattern transfer mask of the present invention, the size of the pattern is formed to be equal to the size of the pattern transferred onto the substrate to be processed.

[0022]

Next, in the pattern transfer method of the present invention, the pattern transfer mask having a pattern formed as a through hole provided in the substrate is irradiated with a charged particle beam to transfer the pattern onto the substrate to be processed. A method for transferring a pattern, comprising configuring a semiconductor device prior to transferring the pattern.
In order to do so , using some of the elements of the pattern to be transferred to the substrate to be processed as a measurement pattern, the step of measuring the coordinates on the pattern transfer mask of this measurement pattern, and from the measured coordinates, the measurement pattern A step of calculating a deviation amount from a design position, and an irradiation angle of the charged particle beam to the pattern transfer mask is controlled based on the deviation amount to irradiate the substrate to be processed with the charged particle beam. A step of moving the position to correct the shift amount and transferring the pattern.

[0024]

[0025]

The pattern transfer method of the present invention is
Kihaka the coordinate measurement of a constant pattern, and is characterized in that performed by irradiating an electromagnetic wave to the pattern transfer mask.

In the pattern transfer method of the present invention, the coordinates of the measurement pattern are measured on a stage on which the pattern transfer mask is placed.

Further, in the pattern transfer method of the present invention, a pattern transfer mask having a pattern formed as a through hole provided in the substrate is irradiated with a charged particle beam to transfer the pattern onto the substrate to be processed. A transfer method, wherein a semiconductor device is configured prior to transferring the pattern.
For using a part of the pattern element to be transferred to the substrate to be processed as a measurement pattern, a step of acquiring an image of this measurement pattern, and an image of the acquired measurement pattern,
A step of calculating the amount of deviation from the design position of the measurement pattern by comparing with the design data of the measurement pattern, and based on the amount of deviation, the irradiation angle of the charged particle beam to the mask for pattern transfer Is controlled to move the irradiation position of the charged particle beam onto the substrate to be processed, correct the deviation amount, and transfer the pattern.

Further, in the pattern transfer method of the present invention, the measurement pattern image is acquired by irradiating the measurement pattern with a test charged particle beam having a cross section smaller than that of the charged particle beam. The feature is that a pattern image of the pattern is acquired.

Further, in the pattern transfer method of the present invention, the image of the measurement pattern is acquired by irradiating the measurement pattern with the test charged particle beam and reflecting the measurement pattern with respect to the test charged particle beam. This is performed by detecting an electronic signal, a secondary electron signal, or a transmitted electron signal.

[0031]

[0032]

In the pattern transfer method of the present invention, the image of the measurement pattern is acquired on the stage on which the pattern transfer mask is placed.

Further, in the pattern transfer method of the present invention, the pattern transfer mask is held at a distance such that deterioration of resolution due to diffraction or scattering of the irradiated charged particle beam with respect to the transferred substrate can be ignored. is there.

Next, the exposure apparatus of the present invention is an exposure apparatus for transferring a pattern onto a substrate to be processed, which has an electron beam emission source and a stage for mounting a pattern transfer mask. , a mask pattern transfer according to any one of claims 1 to 3, on the pattern transfer mask, a coordinate measuring means for measuring the coordinates of the measurement pattern, the measurement pattern, the deviation from the designed position It has coordinate comparison means for calculating the amount, and control means for controlling the irradiation angle of the charged particle beam based on the deviation amount. Further, the exposure apparatus of the present invention is an electron beam emission source.
And a stage for mounting the pattern transfer mask
And an exposure device for transferring a pattern onto a substrate to be processed.
4. The putter according to claim 1, which is a storage device.
On the pattern transfer mask and the pattern transfer mask,
Coordinate measuring means for measuring the coordinates of the measurement pattern,
The amount of deviation of the measurement pattern from the design position was calculated.
And a control means for controlling the irradiation angle of the charged particle beam based on the displacement amount and moving the irradiation position of the electron beam onto the substrate to be processed to correct the displacement amount. It is a thing.

The semiconductor device manufacturing method of the present invention uses the pattern transfer method according to any one of claims 4 to 15 .

The semiconductor device manufacturing method of the present invention measures the overlay accuracy using the measurement pattern transferred onto the substrate to be processed.

[0038]

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a position of a measurement pattern which is a part of a pattern actually formed on a pattern transfer mask prior to actual pattern transfer, By comparing with the design position of this measurement pattern, the deviation amount of the pattern actually formed on the mask from the design data is calculated, and the irradiation angle of the electron beam is calculated according to this deviation amount. The pattern is transferred under control. As a result, a pattern faithful to the design can be transferred to the substrate to be processed.

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be omitted or simplified.

Embodiment 1. FIG. 1 is a schematic top view for explaining the pattern transfer mask used in the first embodiment. Further, FIG. 1A is a diagram showing the entire pattern transfer mask, and FIG. 1B is a part of the pattern,
FIG.1 (c) is the figure which expanded the position measurement pattern.

In FIG. 1A, reference numeral 100 denotes a stencil mask which is a pattern transfer mask. Also, 1
Is a substrate constituting the stencil mask 100, and 2 is a membrane region which is a region for forming a pattern, and is supported by the substrate 1. Membrane area 2 is usually 0.5
It is formed by providing a pattern of stencil holes, which are through holes, on a thin film of silicon or diamond having a film thickness of about 2.0 μm. A structure in which a pattern is formed by providing a stencil hole which is a through hole as described above is called a stencil structure.

The membrane region 2 is usually a portion which becomes a membrane region after an etching stopper film is formed on a silicon substrate by a method such as CVD or thermal oxidation and a silicon or diamond thin film is deposited on the etching stopper film. The silicon substrate on the back surface of is removed by etching, and then the etching stopper film at this portion is removed.

Reference numeral 3 indicates a unit pattern formed in the membrane region 2. Although a plurality of unit patterns 3 are formed in the membrane region 2, they are finally separated into unit patterns to form one semiconductor device. The unit patterns may be the same pattern or different patterns.
Reference numeral 4 denotes a mask alignment mark for aligning the substrate.

In FIG. 1 (b), reference numeral 5 is a gap provided between the adjacent unit patterns 3 and other unit patterns 3, and here serves as a scribe lane. The scribe lane is usually used as a cutting margin for separating a plurality of semiconductor devices formed on a semiconductor substrate,
It is provided between the adjacent unit patterns. Further, 10 indicates a position measurement pattern provided in the gap (scribe lane) 5 and used as a measurement pattern.
In this example, the position measurement pattern 10 is provided at the position where the gap (scribe lane) 5 and the gap (scribe lane) 5 intersect.

In FIG. 1 (c), 10A indicates a slit constituting the position measuring pattern 10. The pattern is
The stencil structure formed as a through hole cannot form a closed pattern (donut pattern) like a donut shape. Therefore, the position measurement pattern 10 that is actually formed is formed in a box-like shape by the four slits 10A as shown in FIG.

In the stencil mask used in the first embodiment, as shown in FIG. 1, a unit pattern 3 which is an actual pattern required as a pattern to be actually transferred to the substrate to be processed, and a stencil mask used for measurement. The entire pattern is configured including the position measurement pattern 10.

FIG. 2 is a schematic sectional view for explaining the structure of the apparatus for electron beam proximity exposure used in the first embodiment of the present invention.

In FIG. 2, 21 indicates an electron beam emission source (cathode), and 22 indicates an extraction electrode (anode). A high voltage of several kV is applied between the electron beam emission source (cathode) 21 and the extraction electrode (anode) 22 by a high voltage source (not shown). Reference numeral 20 denotes an electron beam emitted from the electron beam emission source (cathode) 21 by this high voltage, and the direction indicated by this arrow shows the flow of the electron beam 20.

Reference numeral 23 denotes a focusing electromagnetic field for converging the electron beam 20 emitted from the electron beam emission source (cathode) 21 into a parallel beam, and 24 denotes the focused electron beam 20.
2 shows a restriction diaphragm for blocking unnecessary portions of.

Reference numeral 29 indicates a semiconductor wafer which is a substrate to be processed, and reference numeral 30 indicates a stage on which the stencil mask 100 is placed. The stencil mask 100 has a position measuring pattern 10 formed on the stencil mask 100.
The stage 30 so that the electron beam 20 is vertically irradiated.
Placed on. In addition, the pattern is actually formed on the semiconductor wafer 2
When transferring to 9, the stencil mask 100 is held at a distance from the semiconductor wafer 29 during the irradiation of the electron beam so that deterioration of resolution due to diffraction and scattering of the electron beam can be sufficiently ignored.

Reference numerals 25A and 25B are main deflectors, and 26A and 26B are fine adjustment deflectors. Main deflectors 25A and 2
The electron beam 20 directed to the target direction by 5B
The fine adjustment deflectors 26A and 26B adjust the irradiation angle of the stencil mask 100. The electron beam 20
Can be easily deflected by an electromagnetic field. Utilizing this property, the main deflectors 25A and 25B and the fine adjustment deflectors 26A and 26B deflect the electron beam 20.

27 is a backscattered electron detector, and 28 is
Shows a Faraday cup. The backscattered electron detector 27 is installed on the stencil mask 100 and detects backscattered electrons 20A reflected by the stencil mask 100 and secondary electrons 20B emitted by the stencil mask 100. Also,
The Faraday cup 28 is installed under the stencil mask 100, and the transmitted electrons 2 transmitted through the stencil mask 100 are transmitted.
0C is detected.

Reference numeral 31 is a coordinate measuring means, and 32 is a design coordinate storing means. Further, reference numeral 33 denotes a coordinate comparing means, which can obtain both the measurement coordinates and the design coordinates from the coordinate measuring means 31 and the design coordinate storage means 32 and calculate the deviation amount of the coordinates. Further, reference numeral 34 denotes a deflection driving means, which can control the main deflectors 25A and 25B and the fine adjustment deflectors 26A and 26B to adjust the direction of the electron beam 20. Reference numeral 35 indicates a laser interferometer.

FIG. 3 is a flow chart for explaining the pattern transfer method in the first embodiment, and FIG. 4 is a schematic sectional view for explaining the functions of the fine adjustment deflectors 26A and 26B. A pattern transfer method using the stencil mask 100 will be described with reference to FIG.

In FIG. 3, S1 is a step of placing the stencil mask on the apparatus, and S2 is a position measuring pattern 10.
Of measuring the coordinates on the pattern transfer mask 100, S3 is a step of calculating the amount of deviation of the measured coordinates of the position measuring pattern 10 from the design position, and S4 is
A process of controlling the irradiation angle of the stencil mask 100 with the electron beam 20 based on the amount of deviation to transfer the pattern onto the semiconductor wafer 29 which is the substrate to be processed will be described. Also,
Steps S1 to S3 are performed prior to step S4 in order to determine the irradiation angle of the electron beam during the actual pattern transfer.

First, step S1 of placing the stencil mask 100 on an apparatus for electron beam proximity exposure is performed. Here, the stencil mask 100 performs alignment (positioning) with the mask alignment mark 4 as a reference, and is accurately placed on the stage 30. As a result, the origin of coordinates on the stencil mask 100 and x, y
The coordinates are determined. Such alignment work may use the electron optical system of the device used for pattern transfer, or may use other optical means.

Aligned stencil mask 10
The position 0 is moved according to the coordinate data of the coordinate measurement mark on the stencil mask 100 stored in the design coordinate storage means 32 so that the position measurement pattern 10 comes directly below the optical axis of the electron optical system.

Next, step S2 of measuring the coordinates of the position measurement pattern 10 as a measurement pattern is performed. In FIG. 1, a high voltage of several kV is applied between the electron beam emission source (cathode) 21 and the extraction electrode (anode) 22,
An electron beam 20 is emitted from an electron beam emission source (cathode) 21. The emitted electron beam 20 converges and intersects by the focusing electromagnetic field 23, and reaches the stencil mask 100 at a point (crossover) where the area of the electron beam 20 is minimum. As the electron beam 20 to be irradiated at this time, an electron beam having a finer cross section than the electron beam used in the normal pattern transfer is used.

The deflection driving means 34 drives the main deflectors 25A and 25B, so that the position measurement pattern 10 can be obtained.
The electron beam 20 is irradiated above. Specifically, the deflection driving means 34 drives the main deflector 25A based on the design data, directs the electron beam 20 to the target direction, drives the main deflector 25B, and sets the optical axis L again. Swing back in a direction parallel and perpendicular to the stencil mask 100. The electron beam 20 scans the position measuring pattern 10 by the operation of the deflection driving means 34.

The deflection driving means 34 drives the deflection driving means 34 based on the design data. Therefore, if the stencil mask 100 is formed according to the design data and is not deformed, the electron beam 20 is emitted vertically from directly above the position measurement pattern 10.

In this way, based on the design data,
The electron beam 20 adjusted so that the irradiation angle becomes vertical,
When the stencil mask 100 is irradiated and reflected, the reflected electrons 20A and the stencil mask emits 2
The secondary electron 20B is captured by the backscattered electron detector 27. When the electron beam 20 passes through the stencil mask 100, the transmitted electrons 20C are captured by the Faraday cup 28.

Reflected electrons 20 A of the electron beam 20 and secondary electrons 2
The measured values of 0B and the transmitted electrons 20C and the output signal of the deflection driving means are transmitted to the coordinate measuring means 31. In the coordinate measuring means 31, a scanning electronic signal image is formed based on these transmitted data, and the shape of the designated position measuring pattern is read from the shape storing means (not shown),
The position of the position measurement pattern in the scanning electronic signal image is calculated by pattern matching. After that, the stencil mask 1 is added by adding the position of the position measurement pattern in the scanning electron signal image to the output of the laser interference length measuring machine 35.
The actual coordinates of the position measurement pattern 10 on 00 can be measured.

Next, step S3 of calculating the amount of deviation of the position measurement pattern 10 from the design position is performed based on the coordinates measured in step S2. First, the actual coordinates of the position measurement pattern 10 measured in step S2 are transmitted from the coordinate measuring means 31 to the coordinate comparing means 33. On the other hand, design coordinates of the position measurement pattern 10 are transmitted from the design coordinate storage means 32 to the coordinate comparison means 33. Based on this measured value and the design data from the storage means, the amount of deviation of the position measurement pattern 10 from the design coordinates is calculated.

Next, based on the shift amount calculated in step S3,
Step S4 of transferring the pattern while controlling the irradiation angle is performed. First, the setting of the focused electromagnetic field 23 is changed to the setting for pattern transfer. Further, the semiconductor wafer 29 is installed. In the case of pattern transfer using the stencil mask 100, the semiconductor wafer 29 and the stencil mask 100
The distance between and must be kept at a distance at which degradation of resolution due to diffraction and scattering of the electron beam during electron beam irradiation can be sufficiently ignored, and is preferably several tens nm.

The shift amount calculated in step S3 is transmitted from the coordinate comparing means 33 to the deflection driving means 34. The deflection driving means 34 controls the irradiation angle by adjusting the main deflectors 25A and 25B and the fine adjustment deflectors 26A and 26B so as to correct the amount of deviation from the design position.

As shown in FIG. 4, if the irradiation angle is adjusted by 1 mrad by the fine adjustment deflectors 26A and 26B, the irradiation position of the electron beam 20 on the semiconductor wafer 29 moves by Δ = 50 nm.

Thus, by irradiating the electron beam 20 while controlling the irradiation angle, it is possible to cancel the distortion of the stencil mask 100 and transfer the pattern to a position faithful to the design value.

In this way, the position measuring pattern transferred to the substrate to be processed together with the actual pattern may be used for measuring the overlay accuracy. As a result, the overlay accuracy can be kept high even when the mask position is distorted nonlinearly. Incidentally, in order to manage the overlay accuracy corresponding to the position distortion that occurs non-linearly, it is desirable that there are six or more position measurement patterns inside the transfer area.

In this embodiment, the case where a stencil mask 100 is used as a pattern transfer mask to manufacture a semiconductor wafer has been described as an example, but the present invention is not limited to this, and another pattern transfer mask may be used. It may be used or may be used to process another substrate to be processed.

Further, in this embodiment, the coordinate of the position measurement pattern is measured by acquiring the image of the position measurement pattern and comparing it with the design data, and the shift amount is calculated based on this coordinate. However, the present invention is not limited to this, and other means may be used within the scope of the present invention, such as obtaining the coordinates of the position measurement pattern and calculating the deviation amount from the coordinates.

Further, in order to detect the shift amount of the position measurement pattern, an electron beam having a smaller cross-sectional area than the electron beam used for pattern transfer was used. However, the present invention is not limited to this, and for example, one that uses an electron beam used for pattern transfer or one that uses an electromagnetic wave may be used. In particular, since electromagnetic waves are not easily affected by a disturbance magnetic field and a disturbance electric field, highly accurate position measurement is possible and effective.

Further, in this embodiment, the electron beam 20
Although the method of measuring the amount of deviation by irradiating with and transferring the pattern has been described, the present invention is not limited to this, and other charged particle beams may be irradiated.

Embodiment 2. FIG. 5 is a diagram showing a structure of a stencil mask which is a pattern transfer mask used in the second embodiment of the present invention. Reference numeral 200 denotes the stencil mask used in the second embodiment. Here, the pattern on the stencil mask 200 constitutes a pattern used as a memory device.

Reference numeral 6 indicates a block in which memory cells are arranged in a certain scale, and reference numeral 7 indicates a gap between the block 6 and another block 6. Thus, the memory device usually has a structure in which the blocks 6 are arranged. In the memory device, the degree of pattern integration is high inside the block 6, but the gap 7 between the block 6 and another block 6 has a low pattern density. Therefore, here, the position measurement pattern 10 is arranged in the low density portion around the block 6, that is, in the gap 7 between the blocks 6. Since the other parts are the same as those in the first embodiment, the description thereof will be omitted.

Such a stencil mask 200 has 1
This is effective when two semiconductor devices are large and it is not possible to provide a sufficient number of position measurement patterns between the patterns of the semiconductor devices. By using this, it is possible to transfer a pattern faithful to the design. . In addition, even in the case where the patterns of the plurality of semiconductor devices are arranged on the stencil mask with a gap therebetween, it is possible to provide more position measurement patterns and further improve the overlay accuracy. Then, the pattern can be transferred.

In the gap 7 around the normal block 6, dummy cells are arranged in order to improve the pattern forming accuracy. Therefore, arranging the position measurement pattern 10 adjacent to this does not affect the electrical characteristics of the device.

Although the case of transferring the pattern forming the semiconductor memory device has been described here,
It is not limited to this.

Third Embodiment FIG. 6 shows a pattern forming a logic device formed in the membrane region. Reference numeral 8 indicates a basic logic cell. In the logic device, basic logic cells 8 having a constant height are arranged in a strip shape. No active device is normally present in the gap 9 between the band of the basic logic cell 8 and the band 8 of another basic logic cell. Therefore, the position measurement pattern 10
Are arranged in the gap 9. The position measurement marks arranged on the element isolation layer, the gate layer, the lowermost contact, and the injection layer may be formed in the gap 9. Since the other parts are the same as those in the first embodiment, the description thereof will be omitted.

Although the case of the logic device has been described in this embodiment, in the case of the SOC (system on chip) device in which the memory device and the logic device are combined, the memory device as described in the second embodiment is used. And the case of the logic device described in the third embodiment may be applied to each case.

Fourth Embodiment FIG. 7 is a diagram for explaining a portion used as a measurement pattern among the patterns formed in the membrane region. Figure 7 (a)
In 10B, 10B shows an element pattern used as a measurement pattern, and also shows the pattern of the gate electrode.

In the above-described first to third embodiments, the case where the position measurement pattern is provided at an appropriate position as the measurement pattern and the coordinate is measured has been described. However, in this embodiment, the position measurement pattern is actually measured. An element pattern, which is a portion forming an actual pattern required as a pattern to be transferred, is also used as a measurement pattern. Since the other parts are the same as those in the first embodiment, the description thereof will be omitted.

The measurement pattern 10B constitutes a pattern of the gate electrode which is an element pattern required for the actual pattern. In this way, when the measurement pattern is selected from the actually required actual patterns, the parts of other patterns are It is necessary to select an element pattern having a shape that can be easily distinguished from.

When there are a plurality of shapes that are the same as the element pattern selected as the measurement pattern, the distance d between the element pattern and the measurement pattern must be larger than the distortion amount at the maximum pattern position.

Although the case where the gate electrode is used as the measurement pattern has been described here, the present invention is not limited to this, and as shown in FIG. 7B, it can be easily distinguished from other portions and has the same shape. The element pattern 10C having a sufficient distance from the element pattern of 10 may be selected as the measurement pattern.

In this way, it is not necessary to provide a position measurement pattern, and the actual pattern can be used for accurate alignment and then for accurate formation.

[0087]

As described above, in the present invention, the amount of deviation of the actually formed pattern transfer mask from the design position is calculated before the transfer of the pattern. Therefore, the distortion of the position can be measured with high accuracy, and by controlling the irradiation angle of the electron beam according to this, the shape of the designed pattern can be faithfully transferred to the substrate to be processed.

Further, according to the present invention, since it is not necessary to give the in-plane distribution of the distortion of each pattern transfer mask in advance, it is possible to suppress the deterioration of the processing efficiency.
An accurate pattern transfer can be performed.

Further, according to the present invention, even when the pattern formed on one pattern transfer mask includes a plurality of unit patterns separated by gaps,
Even in the case where one pattern is large and a plurality of unit patterns are included without being separated by a gap, a sufficient position measurement pattern can be provided, and thus accurate pattern transfer can be performed. .

Furthermore, according to the present invention, the amount of deviation can be measured using electromagnetic waves. Therefore, the disturbance magnetic field,
The amount of deviation can be measured without being affected by the disturbance electric field, and more accurate position measurement can be performed.

Further, according to the present invention, since the deviation amount can be measured by irradiating the electron beam having a cross section smaller than that of the electron beam at the time of normal pattern transfer, a smaller pattern can be detected. be able to. Therefore, the position measurement pattern can be miniaturized, the degree of freedom in design can be improved, and the degree of integration of the entire pattern can be improved.

Further, according to the present invention, the actual pattern forming the actual pattern can be substituted for the measurement pattern without providing the measurement pattern. Therefore, it is possible to correct the positional distortion without providing a special pattern, and it is possible to improve the integration degree of the entire pattern.

Further, according to the present invention, when the measurement pattern used to calculate the shift amount is transferred to the substrate to be processed, the transferred measurement pattern can be used to measure the overlay accuracy. As a result, the overlay accuracy can be kept high even when the mask position is distorted nonlinearly.

[Brief description of drawings]

FIG. 1 is a schematic top view for explaining a pattern transfer mask used in a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view for explaining the structure of an apparatus for electron beam proximity exposure used in the present invention.

FIG. 3 is a flowchart for explaining a pattern transfer method according to the present invention.

FIG. 4 is a schematic cross-sectional view for explaining the function of the fine adjustment deflector according to the present invention.

FIG. 5 is a diagram showing a structure of a stencil mask used in the second embodiment of the present invention.

FIG. 6 shows a pattern forming a logic device formed in a membrane region.

FIG. 7 is a diagram for explaining a portion used as a measurement pattern among the patterns formed in the membrane region used in the third embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view for explaining the structure of an apparatus used for low-energy electron beam proximity exposure.

FIG. 9 is a schematic cross-sectional view for explaining the function of the fine adjustment deflector.

[Explanation of symbols]

100, 200, 300 stencil mask 1 substrate 2 Membrane area 3 unit pattern 4 Mask alignment mark 5 Gap (Scribe Lane) 6 blocks Gap between 7 blocks 8 basic logic cells 9 gap 10 Position measurement pattern 10A slit 10B, 10C measurement pattern 20 electron beams 20A backscattered electron 20B secondary electron 20C transmitted electron 21 Electron beam emission source (cathode) 22 Extraction electrode (anode) 23 Focused electromagnetic field 24 Limit diaphragm 25A, 25B Main deflector 26A, 26B Fine adjustment deflector 27 Backscattered electron detector 28 Faraday Cup 29 Processed substrate (semiconductor wafer) 30 stages 31 Coordinate measuring means 32 design coordinate storage means 33 Coordinate comparison means 34 Deflection drive means 35 Laser interferometer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI H01L 21/30 541D (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 1/16 G03F 7 / 20 G03F 9/00

Claims (15)

(57) [Claims] 1. A pattern transfer mask in which a pattern is formed as a through hole provided in a substrate, and the pattern is transferred to a substrate to be processed by irradiation with a charged particle beam, wherein the pattern has a predetermined gap. Including multiple unit patterns placed in
Only the unit pattern is arranged in the unit pattern ,
A pattern transfer mask comprising a position measurement pattern used for measuring coordinate positions on the pattern transfer mask. 2. A pattern transfer mask in which a pattern is formed as a through hole provided in a substrate, and the pattern is transferred to a substrate to be processed by irradiation of a charged particle beam, wherein the pattern is a pattern transfer mask. The position measurement pattern provided for the measurement of the coordinate position on the above is included, and the position measurement pattern is a target for forming a semiconductor device.
A pattern transfer mask, which is an element that constitutes a pattern to be transferred to a processed substrate . 3. The pattern transfer mask according to claim 1, wherein the size of the pattern is equal to the size of the pattern transferred on the substrate to be processed. 4. A pattern transfer method for irradiating a pattern transfer mask having a pattern formed as a through hole provided on a substrate with a charged particle beam to transfer the pattern onto a substrate to be processed. The semiconductor device prior to the transfer of the
Therefore, using a part of the elements of the pattern to be transferred to the substrate to be processed as a measurement pattern, the step of measuring the coordinates on the pattern transfer mask of the measurement pattern, and from the measured coordinates, the measurement pattern, Calculating the amount of deviation from the design position, and controlling the irradiation angle of the charged particle beam to the pattern transfer mask based on the amount of deviation, and the irradiation position of the charged particle beam to the substrate to be processed. And a step of transferring the pattern by correcting the amount of displacement by moving the pattern, and transferring the pattern. 5. The coordinate measurement before Kihaka constant pattern, pattern transfer method according to claim 4, characterized in that by irradiating an electromagnetic wave to the pattern transfer mask. 6. The measurement of coordinates of the measurement pattern, the pattern transfer method according to claim 4 or 5 wherein the pattern transfer mask and performing on stage to be placed. 7. A pattern transfer method for irradiating a pattern transfer mask having a pattern formed as a through-hole provided on a substrate with a charged particle beam to transfer the pattern to a substrate to be processed. The semiconductor device prior to the transfer of the
Therefore, a step of acquiring an image of this measurement pattern by using a part of the elements of the pattern to be transferred to the substrate to be processed as a measurement pattern, and comparing the acquired image of the measurement pattern with the design data of the measurement pattern The step of calculating the amount of deviation of the measurement pattern from the design position by controlling the irradiation angle of the charged particle beam to the pattern transfer mask based on the amount of deviation, and the charged particle beam And a step of moving the irradiation position on the substrate to be processed to correct the deviation amount and transferring the pattern, the pattern transfer method. 8. The image of the measurement pattern is obtained by irradiating the measurement pattern with a test charged particle beam having a cross section smaller than that of the charged particle beam to obtain a pattern image of the measurement pattern. The pattern transfer method according to claim 7 . 9. The acquisition of the image of the measurement pattern is performed by irradiating the test pattern with the test charged particle beam to obtain a backscattered electron signal, a secondary electron signal, of the measurement pattern with respect to the test charged particle beam. Alternatively, the pattern transfer method according to claim 8, which is performed by detecting a transmitted electron signal. 10. The acquisition of the image of the measurement pattern, the pattern transfer method according to any one of claims 7 9 wherein the pattern transfer mask and performing on stage to be placed. 11. the pattern transfer mask, against the transferred substrate, claim 4, characterized in that to hold the distance negligible deterioration of resolution due to diffraction or scattering of the charged particle beam to be irradiated 10 The pattern transfer method according to any one of 1. 12. An exposure apparatus for transferring a pattern onto a substrate to be processed, comprising an electron beam emission source and a stage on which a pattern transfer mask is mounted, the exposure apparatus comprising: A pattern transfer mask, a coordinate measuring means for measuring the coordinates of the measurement pattern on the pattern transfer mask, and a coordinate comparison for calculating the deviation amount of the measurement pattern from the design position. An exposure apparatus comprising: a means for controlling the irradiation angle of the charged particle beam based on the deviation amount. 13. An exposure apparatus for transferring a pattern onto a substrate to be processed, comprising an electron beam emission source and a stage on which a pattern transfer mask is mounted, the exposure apparatus comprising: A pattern transfer mask, a coordinate measuring means for measuring the coordinates of the measurement pattern on the pattern transfer mask, and a coordinate comparison for calculating the deviation amount of the measurement pattern from the design position. Means for controlling the irradiation angle of the charged particle beam based on the deviation amount, and moving the irradiation position of the electron beam on the substrate to be processed to correct the deviation amount. Exposure equipment. 14. A method of manufacturing a semiconductor device, wherein the pattern transfer method according to claim 4 is used. 15. The method of manufacturing a semiconductor device according to claim 14, wherein overlay accuracy is measured using the measurement pattern transferred onto the substrate to be processed.